Patent Application
20220332758
The present application contains a sequence listing that is submitted via EFS-Web concurrent with the filing of this application, containing the file name “21105_0073P1_SL.txt” which is 5,443 bytes in size, created on Sep. 11, 2020, and is herein incorporated by reference in its entirety.
Alzheimer's disease (AD) is a massive global health problem affecting the rapidly growing aging population in U.S. and in the developed world. Drugs effectively preventing the devastating progression of Alzheimer's disease will be of immediate use in patients with preclinical as well as symptomatic Alzheimer's disease. The forecast is that in 2050 more than 1% of the global population will be living with Alzheimer's disease (Brookmeyer R, Johnson E, Ziegler-Graham K, Arrighi H M. Forecasting the global burden of Alzheimer's disease. Alzheimer's Dement [Internet]. 2007 July; 3(3):186-191). Importantly, it has been estimated that a one-year delay in the onset of Alzheimer's disease by 2020 would translate into 9 million fewer cases in 2050: a huge reduction in health care costs (Brookmeyer R, Johnson E, Ziegler-Graham K, Arrighi H M. Forecasting the global burden of Alzheimer's disease. Alzheimer's Dement [Internet]. 2007 July; 3(3):186-191). Thus, a need exists for new therapeutic strategies for treating Alzheimer's disease.
Disclosed herein are compositions comprising:
Disclosed herein are compounds having a structure represented by a formula (Tat1 8,9 TOD; SEQ ID NO: 3):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat1 8,9 Aib; SEQ ID NO: 4):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat5 8,9 Aib; SEQ ID NO: 5):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat1-Dendrite; SEQ ID NO: 6):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are Tat1 analogs with a beta-turn conformation at positions 4-5 and/or 8-9.
The present disclosure can be understood more readily by reference to the following detailed description of the invention, the figures and the examples included herein.
Before the present methods and compositions are disclosed and described, it is to be understood that they are not limited to specific synthetic methods unless otherwise specified, or to particular reagents unless otherwise specified, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, example methods and materials are now described.
Moreover, it is to be understood that unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, and the number or type of aspects described in the specification.
All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.
Definitions
As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.
The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list.
Ranges can be expressed herein as from “about” or “approximately” one particular value, and/or to “about” or “approximately” another particular value. When such a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” or “approximately,” it will be understood that the particular value forms a further aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint. It is also understood that there are a number of values disclosed herein and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. It is also understood that each unit between two particular units is also disclosed. For example, if “about 10 and 15” are disclosed, then 11, 12, 13, and 14 are also disclosed.
As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.
As used herein, the term “sample” is meant a tissue or organ from a subject; a cell (either within a subject, taken directly from a subject, or a cell maintained in culture or from a cultured cell line); a cell lysate (or lysate fraction) or cell extract; or a solution containing one or more molecules derived from a cell or cellular material (e.g., a polypeptide or nucleic acid), which is assayed as described herein. A sample may also be any body fluid or excretion (for example, but not limited to, blood, urine, stool, saliva, tears, bile) that contains cells or cell components.
As used herein, the term “subject” refers to the target of administration, e.g., a human. Thus the subject of the disclosed methods can be a vertebrate, such as a mammal, a fish, a bird, a reptile, or an amphibian. The term “subject” also includes domesticated animals (e.g., cats, dogs, etc.), livestock (e.g., cattle, horses, pigs, sheep, goats, etc.), and laboratory animals (e.g., mouse, rabbit, rat, guinea pig, fruit fly, etc.). In one aspect, a subject is a mammal. In another aspect, a subject is a human. The term does not denote a particular age or sex. Thus, adult, child, adolescent and newborn subjects, as well as fetuses, whether male or female, are intended to be covered.
As used herein, the term “patient” refers to a subject afflicted with a disease, disorder or condition or at risk for a disease, disorder or condition. The term “patient” includes human and veterinary subjects. In some aspects of the disclosed methods, the “patient” has been diagnosed with a need for treatment, such as, for example, prior to an administering step.
As used herein, the term “comprising” can include the aspects “consisting of” and “consisting essentially of.”
As used herein the terms “amino acid” and “amino acid identity” refers to one of the 20 naturally occurring amino acids or any non-natural analogues that may be in any of the antibodies, variants, or fragments disclosed. Thus “amino acid” as used herein means both naturally occurring and synthetic amino acids. For example, homophenylalanine, citrulline and norleucine are considered amino acids for the purposes of the invention. “Amino acid” also includes amino acid residues such as proline and hydroxyproline. The side chain may be in either the (R) or the (S) configuration. In an aspect, the amino acids are in the D- or L-configuration. If non-naturally occurring side chains are used, non-amino acid substituents may be used, for example to prevent or retard in vivo degradation.
“Inhibit,” “inhibiting” and “inhibition” mean to diminish or decrease an activity, level, response, condition, disease, or other biological parameter. This can include, but is not limited to, the complete ablation of the activity, response, condition, or disease. This may also include, for example, a 10% inhibition or reduction in the activity, response, condition, or disease as compared to the native or control level. Thus, in an aspect, the inhibition or reduction can be a 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%, or any amount of reduction in between as compared to native or control levels. In an aspect, the inhibition or reduction is 10-20, 20-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, or 90-100% as compared to native or control levels. In an aspect, the inhibition or reduction is 0-25, 25-50, 50-75, or 75-100% as compared to native or control levels.
“Treatment” and “treating” refer to administration or application of a therapeutic agent (e.g., a Tat 1 analog, peptide or polypeptide described herein) to a subject or performance of a procedure or modality on a subject for the purpose of obtaining a therapeutic benefit of a disease or health-related condition. For example, a treatment may include administration of a pharmaceutically effective amount of a peptide that is capable of activating degradation by the proteasome.
As used herein, the term “treating” refers to partially or completely alleviating, ameliorating, relieving, delaying onset of, inhibiting or slowing progression of, reducing severity of, and/or reducing incidence of one or more symptoms or features of a particular disease, disorder, and/or condition. Treatment can be administered to a subject who does not exhibit signs of a disease, disorder, and/or condition and/or to a subject who exhibits only early signs of a disease, disorder, and/or condition for the purpose of decreasing the risk of developing pathology associated with the disease, disorder, and/or condition. For example, the disease, disorder, and/or condition can be Alzheimer's disease.
A “variant” can mean a difference in some way from the reference sequence other than just a simple deletion of an N- and/or C-terminal amino acid residue or residues. Where the variant includes a substitution of an amino acid residue, the substitution can be considered conservative or non-conservative. Conservative substitutions can be those within the following groups: Ser, Thr, and Cys; Leu, ILe, and Val; Glu and Asp; Lys and Arg; Phe, Tyr, and Trp; and Gln, Asn, Glu, Asp, and His. Variants can include at least one substitution and/or at least one addition, there may also be at least one deletion. Variants can also include one or more non-naturally occurring residues. For example, they may include selenocysteine (e.g., seleno-L-cysteine) at any position, including in the place of cysteine. Many other “unnatural” amino acid substitutes are known in the art and are available from commercial sources. Examples of non-naturally occurring amino acids include D-amino acids, amino acid residues having an acetylaminomethyl group attached to a sulfur atom of a cysteine, a pegylated amino acid, and omega amino acids of the formula NH2(CH2)nCOOH wherein n is 2-6 neutral, nonpolar amino acids, such as sarcosine, t-butyl alanine, t-butyl glycine, N-methyl isoleucine, and norleucine. Phenylglycine may substitute for Trp, Tyr, or Phe; citrulline and methionine sulfoxide are neutral nonpolar, cysteic acid is acidic, and ornithine is basic. Proline may be substituted with hydroxyproline and retain the conformation conferring properties of proline.
As used herein, the term “prevent” or “preventing” refers to preventing in whole or in part, or ameliorating or controlling.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The Tat1 analogs and peptide-based compositions described herein can be useful for the treatment of Alzheimer's disease, and the prevention of Alzheimer's disease because they target early processed in Alzheimer's disease development. The compounds disclosed herein can attack the disease by multiple mechanisms and proved to be effective in cell culture and animal models of Alzheimer's disease. Importantly, they reduce the neural cell death and reduce or even reverse the Alzheimer's disease -related cognitive defects in model animals. None of the drugs currently in clinical or preclinical tests utilize the idea of direct activation of the catalytic core proteasome (Cummings J, Lee G, Ritter A, Zhong K. Alzheimer's disease drug development pipeline: 2018. Alzheimer's Dement Transl Res Clin Interv; 2018; 4:195-214). The compounds disclosed herein can be useful for augmentation of Alzheimer's disease as well as other neurodegenerative diseases (e.g., Parkinson's disease).
Disclosed herein are compounds, compositions, peptides and peptidomimetics that activate degradation by the proteasome and protect against Alzheimer's disease progression. Disclosed herein are compounds, compositions, peptides and peptidomimetics that can work as allosteric regulators of the proteasome and are based on a pharmacophore of strongly basic peptide moieties connected by a stable structural turn. Disclosed herein are compounds, compositions, peptides and peptidomimetics that can enhance several-fold the major peptidase activity (chymotrypsin-like; post-hydrophobic cleavages) of the core. This activity is responsible for majority of cleavages in the proteasomal protein substrates. The activation effect is preserved in the 26S assembly, which is the most advanced and most physiologically relevant among the proteasome assemblies sharing the catalytic core. The proteasome activity enhancement is evident not only in vitro but also in heads and brains of drug-treated flies and mice, respectively, with oral (flies, mice) or IP (mice) treatment route. The findings show that the compounds, compositions, peptides and peptidomimetics disclosed herein reduce cell death in a human cell culture model of Alzheimer's disease, reduce cognitive deficits in a fly model of Alzheimer's disease as well as reduce cognitive deficits in a mouse model of Alzheimer's disease Alzheimer's disease. Evidence is provided herein that shows that injection with these are compounds, compositions, peptides and peptidomimetics is capable of penetrating the blood brain barrier in mice and produces protective effects against Alzheimer's disease-like pathology in animals models of the disease. The results also show that the protective effects from these are compounds, compositions, peptides and peptidomimetics stem from enhanced proteasome function and likely employ multiple mutually supportive mechanisms. The results further demonstrate that these are compounds, compositions, peptides and peptidomimetics reduce levels of β-amyloid naturally present in Alzheimer's disease models and also levels of pre-formed introduced β-amyloid and reduce protein levels of BACE1.
Currently there is no effective treatment for Alzheimer's disease which is a mounting and extremely costly public health problem. The compounds, compositions, peptides, peptidomimetics and methods described herein represent the first demonstration that a direct enhancement of proteasome function with designer compounds can protect from Alzheimer's disease pathology and disease progression. An important aspect of the present disclosure is that these are compounds, compositions, peptides and peptidomimetics act through both β-amyloid dependent and independent mechanisms. This is important because most of the failed clinical trials for Alzheimer's disease have been based on technologies which target removal of β-amyloid. Most likely, such intervention comes too late during the irreversible progress of the disease. To the contrary, the compounds, compositions, peptides and peptidomimetics disclosed herein target earlier stages of disease development and thus may prevent neuronal damage. Multiple actions of the compounds, compositions, peptides and peptidomimetics described herein (e.g., activators) augmenting performance of the ubiquitin-proteasome pathway in general and the proteasome in particular: (i) general improvement of protein turnover in aging brain cells; (ii) prevention of formation of polymerization-prone toxic monomers; and (iii) elimination of the toxic monomers before they polymerize and irreversibly harm the cells in brain.
Proteasome is an important protease from the ubiquitin-proteasome pathway responsible for majority of regulated protein turnover in human cells. The giant protease consists of 20S catalytic core that can be decorated with specific protein regulatory modules to form 26S proteasome, distinct forms of “activated” proteasome and a variety of mixed-module assemblies. Small-molecule inhibitors of the catalytic core are established anti-cancer drugs. Small-molecule or peptide-based activators are scarce, with limited reports of in vitro and cell culture tests. The “detergent-activator” often used for in vitro tests with the core proteasome, sodium dodecyl sulfate, is unsuitable as a lead since it damages the enzyme and destroys its ability to interact with regulatory modules.
The compounds, compositions, peptides and peptidomimetics disclosed herein can be referred to as “the Tat compounds”, “Tat1 analog” or “Tat1 analogs” and are based on fragments of a viral protein, the HIV-1Tat that binds the 20S core proteasome and competes with the “activator” module. The peptide fragments of the viral protein such as Tat1 and Tat2 are ultimately degraded by the proteasome and thus unsuitable as leads in the unmodified form (Jankowska E, et al. Biopolymers. 2010; 93(5):481-495).
For example, in an aspect, following small-scale SAR studies, a structural beta turn was introduced to the strongly positive Tat1 structure to improve bio-stability and potency toward the core proteasome. The Tic-Oic (TO) provides a synthetic beta turn in Tat-TOD and also in simplified peptidomimetic Tat-3KTO (abbreviated as Tat-KTO) and in Tat-ATO, a negative control devoid of the strong positive charge. A stable beta turn was also introduced to the Tat1 structure by Aib, and a resulting mimetic was a strong activator. The three-turns-like and branching effect in a strong activator Tat Dendrite is achieved with the central benzene.
Tat-TOD and Tat-Den in vitro strongly enhance catalytic performance of the major peptidase (chymotrypsin-like, post-hydrophobic cleavages) of the latent human housekeeping core 20S proteasome at high nanomolar/low micromolar concentrations. The compounds also elevate peptidase activity of the fully assembled human 26S proteasome, an uncommon feature for non-protein regulators. Activation of the 20S core is preserved in the simplified Tat-KTO, however it is low in the ATO derivative, pointing at the significance of both positive charge and a stable structural turn for the biological effect on proteasome. Destabilization of the turn by introducing alanine residues to the Tat1 structure destroyed the activation potency. Introduction of two adjacent turns in the Tat1 structure (Tat1 51/55-TOD) eliminated the activation as well, likely due to a steric hindrance by two rigid turns.
It was tested whether a stable beta turn flanked by short peptide moieties with net positive charge is the proteasome-activating pharmacophore.
Treatment of Drosophila melanogaster that model aspects of Alzheimer's disease with either Tat1 8,9TOD or Tat-Dendrite (mixed into food) significantly enhances response to measures of learning, memory and functionality. Improved performance in olfaction aversion training and increased spontaneous activity was observed in elav-GS-Gal4>UAS-APP, UAS-Bace1 flies fed 1 μM Tat-TOD and 1 μM Tat-Den.
Treatment of Tat-TOD significantly enhances cell survival in a cell line that models aspects of Alzheimer's disease. The MC65 cell line overexpresses a C99 fragment of the β-amyloid precursor protein APP under withdrawal of tetracycline, which causes cell death. Treatment with Tat-TOD significantly reduces cell death in this line under conditions of tetracycline withdrawal.
Treatment of Tat-TOD significantly enhances proteasome activity in the central nervous system of mice 24 hours after intraperitoneal injection. Significant increases are seen in a cell line that models aspects of Alzheimer's disease. The MC65 cell line overexpresses a C99 fragment of the β-amyloid precursor protein APP under withdrawal of tetracycline that causes cell death. Treatment 0.04, 0.2 and 1 mg/kg.
Injection of hAPP(J20) mice (which model aspects of Alzheimer's disease pathogenesis) with Tat-TOD significantly reduces protein levels of β-amyloid and protein levels of BACE1 (part of β-amyloid machinery).
Injection of hAPP(J20) mice with Tat-TOD significantly enhances learning and memory based on performance in a novel object recognition.
As described herein, proteasome is an important enzyme of controlled proteolysis responsible for the catabolic arm of proteostasis. The proteasome-dependent functions include among many others, processes important for neuronal functions such as synaptic plasticity, vesicle transport, and synaptic signaling. Ominously, proteasome activity is known to be lowered and followed by deregulation of proteasome-related degradation in brains ravaged by Alzheimer's disease. Consequently, deterioration of the proteasome-related proteostasis would be expected to affect neuronal functions and to drive many of the physiological and symptomatic deficits observed under Alzheimer's disease. Thus, augmentation of the proteasome activity may at least prevent the progression of Alzheimer's disease. To meet the challenge, a set of Tat1 analogs (also herein referred to as proteasome-activating peptidomimetics) based on proteasome-binding and blood-brain-barrier-passing fragments of the viral protein HIV-1 Tat was developed. These compounds enhance the major peptidase activity of the proteasome in vitro by an allosteric mechanism. The activation effect is preserved in cellulo and in vivo. The compounds at low-micromolar concentrations reduce cell death in cell lines that either overexpress APP (amyloid precursor protein) or have been treated with β-amyloid. The peptides and peptidomimetics described herein effectively cross the blood brain barrier in mice and to reduce or even reverse Alzheimer's disease -related deficits in learning and memory in fruit fly and mouse models.
Compositions
Disclosed herein are Tat1 analogs. For example, Tat1 analogs can be any of SEQ ID NOs: 3-6. In some aspects, the Tat1 analog can be one or more of the sequences or structures shown in
Also disclosed herein are compositions, including pharmaceutical compositions comprising Tat1 analogs, or variants and/or fragments of Tat1 or Tat1 analogs. Disclosed herein are compositions, including pharmaceutical compositions, comprising a Tat1 analog, or variants and/or fragments of Tat1 or Tat1 analogs capable of activating 20S and/or 26S proteasome activity. Also, disclosed herein are compositions, including pharmaceutical compositions, comprising a Tat1 analog, or variants and/or fragments of Tat1 or Tat1 analogs, capable of ameliorating one or more symptoms of Alzheimer's disease in a subject. Further disclosed herein are compositions, including pharmaceutical compositions, comprising a Tat1 analog, or variants and/or fragments of Tat1 or Tat1 analogs capable of increasing turnover of amyloid precursor protein or β-secretase enzyme BACE1.
Disclosed herein are compositions comprising any of the peptides disclosed herein, including but not limited to Tat1 analogs. In some aspects the peptide can comprise the amino acid sequence GRKKRRQ-AibG-RPS (SEQ ID NO: 4), or a fragment or variant thereof; GRKKRRQ-AibG-QRRKKRG (SEQ ID NO: 5), or a fragment or variant thereof; or the amino acid sequence (Tat1-Dendrite) SEQ ID NO: 6, or a fragment or variant thereof.
Disclosed herein are compositions comprising peptides that comprise the amino acid sequence of SEQ ID NO: 3: GRKKRRQ-TOD-RPS; SEQ ID NO: 4: GRKKRRQ-AIBG-RPS; SEQ ID NO: 5: GRKKRRQ-AibG-QRRKKRG; or SEQ ID NO: 6: Tat1-Dendrite.
In some aspects, the peptides comprise the amino acid sequence GRKKRRQ-TOD-RPS (SEQ ID NO: 3). In some aspects, the peptides comprise the amino acid sequence GRKKRRQ-AIBG-RPS (SEQ ID NO: 4). In some aspects, the peptides comprise the amino acid sequence GRKKRRQ-AibG-QRRKKRG (SEQ ID NO: 5). In some aspects, the peptides comprise the amino acid sequence (Tat1-Dendrite) (SEQ ID NO: 6).
In some aspects, the peptides described herein can have at least 80% sequence identity to any of SEQ ID NOs: 1, and 3-6. In some aspects, the peptides described herein can have at least 85% sequence identity, at least 90% sequence identify, at least 95% sequence identity, or at least 98% sequence identity to any of SEQ ID NOs: 3-6.
In some aspects, any of the compositions described herein can further comprise a pharmaceutically acceptable carrier. In some aspects, any of the compositions described herein can be formulated for intravenous, subcutaneous or intranasal administration.
Disclosed herein are peptides that comprise variants of GRKKRRQRRRPS (SEQ ID NO: 1). In some aspects, the variants can comprise a sequence having at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99% identity to SEQ ID NO: 1. In some aspects, the variants retain at least 50%, 75%, 80%, 85%, 90%, 95% or 99% of the biological activity of the reference protein described herein.
Disclosed herein are peptides that comprise variants of GRKKRRQ-TOD-RPS (SEQ ID NO: 3), GRKKRRQ-AIBG-RPS (SEQ ID NO: 4), GRKKRRQ-AibG-QRRKKRG (SEQ ID NO: 5), or SEQ ID NO: 6 (Tat1-dendrite). In some aspects, the variants can comprise a sequence having at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99% identity to SEQ ID NO: 1, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, or SEQ ID NO: 6. In some aspects, the variants retain at least 50%, 75%, 80%, 85%, 90%, 95% or 99% of the biological activity of the reference protein described herein.
As used herein, the term “peptide” refers to a linear molecule formed by binding amino acid residues to each other via peptide bonds. As used herein, the term “polypeptide” refers to a polymer of (the same or different) amino acids bound to each other via peptide bonds.
In some aspects, the peptide or polypeptide can be of any length so long as the peptides described herein can activate 20S and/or 26S proteasome activity.
In some aspects, the peptides described herein can further comprise 1, 2, 2, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 amino acid residues at the N-terminal end of the disclosed peptides. In some aspects, the peptides described herein can further comprise 1, 2, 2, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 amino acid residues at the C-terminal end of the disclosed peptides disclosed herein. For example, disclosed herein a Ta1 analogs that comprise SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, or SEQ ID NO: 6 and further comprise 1, 2, 2, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 amino acid residues at the N-terminal or C-terminal end of the Tat1 analog. In some aspects, the amino acid residues that can be present at either the N-terminal end or the C-terminal end of any of the peptides disclosed herein can be unimportant for activating 20S and/or 26S proteasome activity. In some aspects, the amino acid residues added to the N-terminal end or the C-terminal end of the peptides disclosed herein may prevent ubiquitination, improve stability, help maintain the three dimensional structure of the peptide (e.g., Tat1 analog), or a combination thereof.
In some aspects, the peptides disclosed herein can further comprise one or more amino acid residues that comprise a modified side chain. In some aspects, one or more amino acids of any of the peptides disclosed here can have a modified side chain. Examples of side chain modifications include but are not limited to modifications of amino acid groups, such as reductive alkylation; amidination with methylacetimidate; acylation with acetic anhydride; carbamolyation of amino groups with cynate; trinitrobenzylation of amino acid with 2,4,6-trinitrobenzene sulfonic acid (TNBS); alkylation of amino groups with succinic anhydride; and pyridoxylation with pridoxal-5-phosphate followed by reduction with NaBH4.
In some aspects, a guanidine group of an arginine residue may be modified by the formation of a heterocyclic condensate using a reagent, such as 2,3-butanedione, phenylglyoxal, and glyoxal. In some aspects, the carboxyl group may be modified by carbodiimide activation via O-acylisourea formation, followed by subsequent derivatization, for example, to a corresponding amide.
In some aspects, a sulfhydryl group may be modified by methods, such as carboxymethylation with iodoacetic acid or iodoacetamide; performic acid oxidation with cysteic acid; formation of mixed disulfides by other thiol compounds; a reaction by maleimide, maleic anhydride, or other substituted maleimide; formation of mercury derivatives using 4-chloromercuribenzoate, 4-chloromercuriphenylsulfonic acid, phenylmercury chloride, 2-chloromercuri-4-nitrophenol, and other mercurial agents; and carbamolyation with cyanate at alkaline pH. In addition, the sulfhydryl group of cysteine may be substituted with a selenium equivalent, whereby a diselenium bond may be formed instead of at least one disulfide bonding site in the peptide.
In some aspects, the tryptophan residue may be modified by, for example, oxidation with N-bromosuccinimide or alkylation of the indole ring by 2-hydroxy-5-nitrobenzyl bromide or sulfonyl halide. Meanwhile, the tyrosine residue may be modified by nitration using tetranitromethane to form a 3-nitrotyrosine derivative.
In some aspects, the modification of the imidazole ring of a histidine residue may be accomplished by alkylation with an iodoacetic acid derivative or N-carbethoxylation with diethylpyrocarbonate.
In some aspects, the proline residue may be modified by, for example, hydroxylation at the 4-position.
In some aspects, the peptides described herein can be further modified to improve stability. In some aspects, any of the amino acid residues of the peptides described herein can be modified to improve stability. In some aspects, peptide can have at least one amino acid residue that has an acetyl group, a fluorenylmethoxy carbonyl group, a formyl group, a palmitoyl group, a myristyl group, a stearyl group, or polyethylene glycol. In some aspects, an acetyl protective group can be bound to the peptide described herein.
As used herein, the term “peptide” can also be used to include functional equivalents of the peptides described herein (e.g., functional equivalents of the Tat1 analogs disclosed herein). As used herein, the term “functional equivalents” can refer to amino acid sequence variants having an amino acid substitution, addition, or deletion in some of the amino acid sequence of the peptide or polypeptide while simultaneously having similar or improved biological activity, compared with the peptide as described herein. In some aspects, the amino acid substitution can be a conservative substitution. Examples of the naturally occurring amino acid conservative substitution include, for example, aliphatic amino acids (Gly, Ala, and Pro), hydrophobic amino acids (Ile, Leu, and Val), aromatic amino acids (Phe, Tyr, and Trp), acidic amino acids (Asp and Glu), basic amino acids (His, Lys, Arg, Gln, and Asn), and sulfur-containing amino acids (Cys and Met). In some aspects, the amino acid deletion can be located in a region that is not directly involved in the activity of the peptide and polypeptide disclosed herein.
In some aspects, the amino acid sequence of the peptides described herein can include a peptide sequence that has substantial identity to any of sequence of the peptides disclosed herein. As used herein, the term “substantial identity” means that two amino acid sequences, when optimally aligned and then analyzed by an algorithm normally used in the art, such as BLAST, GAP, or BESTFIT, or by visual inspection, share at least about 60%, 70%, 80%, 85%, 90%, or 95% sequence identity. Methods of alignment for sequence comparison are known in the art.
In some aspects, the amino acid sequence of the peptides described herein can include a peptide sequence that has some degree of identity or homology to any of sequences of the peptides disclosed herein. The degree of identity can vary and be determined by methods known to one of ordinary skill in the art. The terms “homology” and “identity” each refer to sequence similarity between two polypeptide sequences. Homology and identity can each be determined by comparing a position in each sequence which can be aligned for purposes of comparison. When a position in the compared sequence is occupied by the same amino acid residue, then the polypeptides can be referred to as identical at that position; when the equivalent site is occupied by the same amino acid (e.g., identical) or a similar amino acid (e.g., similar in steric and/or electronic nature), then the molecules can be referred to as homologous at that position. A percentage of homology or identity between sequences is a function of the number of matching or homologous positions shared by the sequences. The peptides described herein can have at least or about 25%, 50%, 65%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity or homology to the peptide or polypeptide, wherein the peptide is one or more of SEQ ID NOs: 1, 3-6.
Disclosed herein are compounds having a structure represented by a formula (Tat1 8,9 TOD; SEQ ID NO: 3):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat1 8,9 Aib; SEQ ID NO: 4):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat1-Dendrite; SEQ ID NO: 6):
or a pharmaceutically acceptable salt thereof.
Disclosed herein are compounds having a structure represented by a formula (Tat5 8,9 Aib; SEQ ID NO: 5):
or a pharmaceutically acceptable salt thereof.
As used herein, the term “stability” refers to storage stability (e.g., room-temperature stability) as well as in vivo stability. The foregoing protective group can protect the peptides described herein from the attack of protein cleavage enzymes in vivo.
Pharmaceutical Compositions
As disclosed herein, are pharmaceutical compositions, comprising the peptides and/or Tat1 analogs described herein. Also disclosed herein, are pharmaceutical compositions, comprising the peptides and/or Tat1 analogs described herein and a pharmaceutical acceptable carrier. Further disclosed herein are pharmaceutical compositions for increasing turnover of amyloid precursor protein or β-secretase enzyme BACE1; activating 20S or 26S proteosome activity; ameliorating one or more symptoms of Alzheimer's disease; or increasing 20S or 26S proteasome activity in a subject. In some aspects, the pharmaceutical compositions can comprise: a) a therapeutically effective amount of the peptides and/or Tat1 analogs described herein; and b) a pharmaceutically acceptable carrier.
The pharmaceutical compositions described above can be formulated to include a therapeutically effective amount of a peptides and/or Tat1 analogs disclosed herein. Therapeutic administration encompasses prophylactic applications. Based on genetic testing and other prognostic methods, a physician in consultation with their patient can choose a prophylactic administration where the patient has a clinically determined predisposition or increased susceptibility (in some cases, a greatly increased susceptibility) to Alzheimer's disease.
The pharmaceutical compositions described herein can be administered to the subject (e.g., a human patient) in an amount sufficient to delay, reduce, or preferably prevent the onset of clinical disease. Accordingly, in some aspects, the patient can be a human patient. In therapeutic applications, compositions can be administered to a subject (e.g., a human patient) already with or diagnosed with Alzheimer's disease in an amount sufficient to at least partially improve a sign or symptom or to inhibit the progression of (and preferably arrest) the symptoms of the condition, its complications, and consequences (e.g., developing Alzheimer's disease). An amount adequate to accomplish this is defined as a “therapeutically effective amount.” A therapeutically effective amount of a pharmaceutical composition can be an amount that achieves a cure, but that outcome is only one among several that can be achieved. As noted, a therapeutically effect amount includes amounts that provide a treatment in which the onset or progression of Alzheimer's disease or a symptom of Alzheimer's disease is ameliorated. One or more of the symptoms can be less severe. Recovery can be accelerated in an individual who has been treated.
In some aspects, the pharmaceutical composition can be formulated for intravenous administration. In some aspects, the pharmaceutical composition can be formulated for subcutaneous, intranasal, oropharyngeal or oral administration. The compositions can be formulated for administration by any of a variety of routes of administration, and can include one or more physiologically acceptable excipients, which can vary depending on the route of administration. As used herein, the term “excipient” means any compound or substance, including those that can also be referred to as “carriers” or “diluents.” Preparing pharmaceutical and physiologically acceptable compositions is considered routine in the art, and thus, one of ordinary skill in the art can consult numerous authorities for guidance if needed.
The pharmaceutical compositions as disclosed herein can be prepared for oral or parenteral administration. Pharmaceutical compositions prepared for parenteral administration include those prepared for intravenous (or intra-arterial), intramuscular, subcutaneous, intraperitoneal, transmucosal (e.g., intranasal, intravaginal, or rectal), or transdermal (e.g., topical) administration. Aerosol inhalation can also be used to deliver the peptides disclosed herein. Thus, compositions can be prepared for parenteral administration that include the peptides dissolved or suspended in an acceptable carrier, including but not limited to an aqueous carrier, such as water, buffered water, saline, buffered saline (e.g., PBS), and the like. One or more of the excipients included can help approximate physiological conditions, such as pH adjusting and buffering agents, tonicity adjusting agents, wetting agents, detergents, and the like. Where the compositions include a solid component (as they may for oral administration), one or more of the excipients can act as a binder or filler (e.g., for the formulation of a tablet, a capsule, and the like). Where the compositions are formulated for application to the skin or to a mucosal surface, one or more of the excipients can be a solvent or emulsifier for the formulation of a cream, an ointment, and the like.
The pharmaceutical compositions can be sterile and sterilized by conventional sterilization techniques or sterile filtered. Aqueous solutions can be packaged for use as is, or lyophilized, the lyophilized preparation, which is encompassed by the present disclosure, can be combined with a sterile aqueous carrier prior to administration. The pH of the pharmaceutical compositions typically will be between 3 and 11 (e.g., between about 5 and 9) or between 6 and 8 (e.g., between about 7 and 8). The resulting compositions in solid form can be packaged in multiple single dose units, each containing a fixed amount of the above-mentioned agent or agents, such as in a sealed package of tablets or capsules. The composition in solid form can also be packaged in a container for a flexible quantity, such as in a squeezable tube designed for a topically applicable cream or ointment.
Methods of Treatment
Disclosed herein are methods of increasing 20S or 26S proteasome activity in a subject. In some aspects, the methods can comprise administering to the subject with a disease a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier. In some aspects, the 20S or the 26S proteasome activity can be increased. In some aspects, the chymotrypsin-like activity of latent human 20S proteasome can be activated. In some aspects, the chymotrypsin-like activity of latent human 26S proteasome can be activated. In some aspects, the composition increases degradation of Aβ machinery/substrate. In some aspects, the disease can be Alzheimer's disease or a cancer. In some aspects, the cancer can be a blood cancer.
Disclosed herein are methods treating a disease. In some aspects, the treating of the disease requires proteasome activation. In some aspects, the methods can comprise administering to a subject with the disease a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier. In some aspects, the 20S or the 26S proteasome activity can be increased. In some aspects, the chymotrypsin-like activity of latent human 20S proteasome can be activated. In some aspects, the chymotrypsin-like activity of latent human 26S proteasome can be activated. In some aspects, the composition increases degradation of Aβ machinery/substrate. In some aspects, the disease can be Alzheimer's disease or a cancer. In some aspects, the cancer can be a blood cancer.
Disclosed herein are methods of increasing turnover of amyloid precursor protein or β-secretase enzyme BACE1. In some aspects, the methods can comprise administering to a subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier.
Disclosed herein are methods of increasing survival of neuroblasts. In some aspects, the methods can comprise administering to a subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier.
Disclosed herein are methods of reducing amyloid precursor protein levels. In some aspects, the methods can comprise administering to a subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier.
Disclosed herein are methods of improving cognitive function in a subject. In some aspects, the methods can comprise administering to the subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier.
Disclosed herein are methods of activating 20S or 26S proteosome activity. In some aspects, the methods can comprise administering to a subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier. In some aspects, the 20S or the 26S proteasome activity can be increased. In some aspects, the chymotrypsin-like activity of latent human 20S proteasome can be activated. In some aspects, the chymotrypsin-like activity of latent human 26S proteasome can be activated. In some aspects, the composition increases degradation of Aβ machinery/substrate.
Disclosed herein are methods of ameliorating one or more symptoms of Alzheimer's disease. In some aspects, the methods can comprise administering to a subject a therapeutically effective amount of a composition of any of the peptides or compounds or pharmaceutical compositions disclosed herein. In some aspects, the compositions can further comprise a pharmaceutically acceptable carrier. In some aspects, the 20S or the 26S proteasome activity can be increased. In some aspects, the chymotrypsin-like activity of latent human 20S proteasome can be activated. In some aspects, the chymotrypsin-like activity of latent human 26S proteasome can be activated. In some aspects, the composition increases degradation of Aβ machinery/substrate.
In some aspects, the methods can comprise administering a composition that can be formulated for intravenous, subcutaneous, intranasal, or oral administration.
In some aspects, the subject can be identified as being in need of treatment before the administration step. In some aspects, the subject can have Alzheimer's disease. In some aspects, the subject can have a cancer. In some aspects, the cancer can be a blood cancer.
Amounts effective for this use can depend on the severity of the condition, disease or disease or the severity of the risk of the condition, disease or disorder, and the weight and general state and health of the subject, but generally range from about 0.05 μg to about 1000 μg (e.g., 0.5-100 μg) of an equivalent amount of the peptide per dose per subject. Suitable regimes for initial administration and booster administrations are typified by an initial administration followed by repeated doses at one or more hourly, daily, weekly, or monthly intervals by a subsequent administration. For example, a subject can receive peptides in the range of about 0.05 to 1,000 μg equivalent dose per dose one or more times per week (e.g., 2, 3, 4, 5, 6, or 7 or more times per week). For example, a subject can receive 0.1 to 2,500 μg (e.g., 2,000, 1,500, 1,000, 500, 100, 10, 1, 0.5, or 0.1 μg) dose per week. A subject can also receive peptides in the range of 0.1 to 3,000 μg per dose once every two or three weeks. A subject can also receive 2 mg/kg every week (with the weight calculated based on the weight of the peptide.
The total effective amount of the peptides disclosed herein in the pharmaceutical compositions disclosed herein can be administered to a mammal as a single dose, either as a bolus or by infusion over a relatively short period of time, or can be administered using a fractionated treatment protocol in which multiple doses are administered over a more prolonged period of time (e.g., a dose every 4-6, 8-12, 14-16, or 18-24 hours, or every 2-4 days, 1-2 weeks, or once a month). Alternatively, continuous intravenous infusions sufficient to maintain therapeutically effective concentrations in the blood are also within the scope of the present disclosure.
The therapeutically effective amount of the peptides present within the compositions described herein and used in the methods as disclosed herein applied to mammals (e.g., humans) can be determined by one of ordinary skill in the art with consideration of individual differences in age, weight, and other general conditions (as mentioned above).
Kits
The kits can comprise one or more of the peptides or pharmaceutical compositions disclosed herein. The peptides or compositions described herein can be packaged in a suitable container labeled, for example, for use to treat Alzheimer's disease or a cancer. Accordingly, packaged products (e.g., sterile containers containing the composition described herein and packaged for storage, shipment, or sale at concentrated or ready-to-use concentrations) and kits, including at least one or more of the peptides as described herein and instructions for use, are also within the scope of the disclosure. A product can include a container (e.g., a vial, jar, bottle, bag, or the like) containing the peptides or compositions described herein. In addition, the kits further may include, for example, packaging materials, instructions for use, syringes, buffers or other control reagents for treating or monitoring the condition for which prophylaxis or treatment is required. The product may also include a legend (e.g., a printed label or insert or other medium describing the product's use (e.g., an audio- or videotape)). The legend can be associated with the container (e.g., affixed to the container) and can describe the manner in which the compound therein should be administered (e.g., the frequency and route of administration), indications therefor, and other uses. The peptides or compositions can be ready for administration (e.g., present in dose-appropriate units), and may include a pharmaceutically acceptable adjuvant, carrier or other diluent. Alternatively, the compounds can be provided in a concentrated form with a diluent and instructions for dilution.
Abstract. The proteasome has roles in neuronal proteostasis, including removal of misfolded or oxidized proteins, presynaptic protein turnover, as well as synaptic efficacy and plasticity. Proteasome dysfunction is a feature of Alzheimer's disease (Almeida, C. G., et al. The Journal of neuroscience: the official journal of the Society for Neuroscience 26, 4277-4288, doi:10.1523/JNEUROSCI.5078-05.2006 (2006); Shringarpure, R., et al. Cell Mol Life Sci 57, 1802-1809 (2000); and Rosen, K. M. et al. Journal of neuroscience research 88, 167-178, doi:10.1002/jnr.22178 (2010)). Artificially impairing proteasome can mimic many neurodegeneration-like phenotypes (Bedford, L. et al. J Neurosci 28, 8189-8198, doi:10.1523/JNEUROSCI.2218-08.2008 (2008); and Romero-Granados, R., et al. PLoS One 6, e28927, doi:10.1371/journal.pone.0028927 (2011)). The results disclosed herein show that manipulation of proteasome activity can influence the rate of Alzheimer's disease-like progression. The results also show that augmentation of proteasome function in flies and cell cultures delays Alzheimer's disease-like mortality, cell death and cognitive deficits. Described herein is a transgenic mouse with neuronal-specific proteasome overexpression. When crossed with a mouse model of Alzheimer's disease, reduced mortality and diminished Alzheimer's disease-like cognitive deficits result. To establish translational relevance, a set of proteasome activating peptide mimetics based on modification of the HIV protein TAT1 were developed. These agonists enhance 20S as well as 26S proteasome activity and stably penetrate the blood-brain-barrier. The results also show that treatment with these agonists protect against Alzheimer's disease-like cell death in a cell culture model of Alzheimer's disease and cognitive decline as well as mortality in fly, and mouse models of Alzheimer's disease. The protective effects observed from proteasome overexpression in the models described herein appear at least in part driven by increased turnover of the amyloid precursor protein (APP) or β-secretase enzyme BACE1 by the proteasome. The results disclosed herein demonstrate that proteasome plays an important role in Alzheimer's disease-like pathogenesis in diverse models of the disease, and thus that it may represent a new therapeutic target for Alzheimer's disease.
Alzheimer's disease affects millions world-wide, producing cognitive deficits and increased mortality. Brain tissue from patients with Alzheimer's disease have reduced proteasome function (Keller, J. N., et al. J Neurochem 75, 436-439, doi:10.1046/j.1471-4159.2000.0750436.x (2000); and Keck, S., et al. J Neurochem 85, 115-122, doi:10.1046/j.1471-4159.2003.01642.x (2003)). Proteasome represents the major, multifunctional and multi-subunit protease of the ubiquitin-proteasome-pathway (Keller, J. N., et al. J Neurochem 75, 436-439, doi:10.1046/j.1471-4159.2000.0750436.x (2000)). Proteasome impairment in Alzheimer's disease represents a robust feature of the disease occurring in mouse, cell culture and Drosophila models of Alzheimer's disease (
Alzheimer's disease was initially modelled through overexpression of wild-type human APP and BACE1, with expression limited to post-adulthood to avoid developmental artifacts (
Proteasome function was enhanced through overexpression of Prosβ5 (major, chymotrypsin-like peptidase in proteasome core (Heinemeyer, W., et al. J Biol Chem 272, 25200-25209, doi:10.1074/jbc.272.40.25200 (1997))). Proteasome assembly can be driven via an autoregulatory process where overexpression of Prosβ5 increases whole proteasome assembly and expression of other proteasome subunits in cell culture (Chondrogianni, N. et al. J Biol Chem 280, 11840-11850, doi:10.1074/jbc.M413007200 (2005)), C. elegans (Chondrogianni, N., et al. Faseb J 29, 611-622, doi:10.1096/fj.14-252189 (2015)) and Drosophila (Munkacsy, E. et al. Aging Cell, e13005, doi:10.1111/acel.13005 (2019); and Nguyen, N. N. et al. Sci Rep 9, 3170, doi:10.1038/s41598-019-39508-4 (2019)).
Prosβ5 overexpression prevents Alzheimer's disease-like proteasome activity deficits (
To investigate the translational potential, a transgenic mouse containing an additional copy of mouse PSMB5 (Prosβ5 orthologue) fused to the Neuron Specific Enolase promoter (Mi, J. et al. PLoS One 8, e83609, doi:10.1371/journal.pone.0083609 (2013)) (NSE-PSMB5) (
To establish if proteasome overexpression could protect against Alzheimer's disease-like deficits in a mouse model of Alzheimer's disease, NSE-PSMB5 was crossed with hAPP(J20) (Mucke, L. et al. J Neurosci 20, 4050-4058 (2000)) mice which overexpress familial-mutant human APP and recapitulate aspects of Alzheimer's disease pathogenesis (Wright, A. L. et al. PLoS One 8, e59586, doi:10.1371/journal.pone.0059586 (2013); Hong, S. et al. Science 352, 712-716, doi:10.1126/science.aad8373 (2016); Cheng, I. H. et al. J Biol Chem 282, 23818-23828, doi:10.1074/jbc.M701078200 (2007); and Saganich, M. J. et al. J Neurosci 26, 13428-13436, doi:10.1523/JNEUROSCI.4180-06.2006 (2006)) (
The proteasome protective effects may stem from degradation of the Aβ precursor machinery and substrate. Previous reports have shown APP, BACE1 and γ-secretase activating protein GSAP are degraded by the proteasome, and treatment of cells with proteasome inhibitors increases BACE1 and GSAP (Qing, H. et al. Faseb J 18, 1571-1573, doi:10.1096/fj.04-1994fje (2004); Nunan, J. et al. J Neurosci Res 74, 378-385, doi:10.1002/jnr.10646 (2003); and Chu, J., et al. J Neurochem 133, 432-439, doi:10.1111/jnc.13011 (2015)). Enhancing proteasome function in flies that overexpress hAPP and hBace1 resulted in significantly less detectable APP protein (
Next, it was determined whether pharmacologic manipulations which enhance proteasome function could also reduce Alzheimer's disease-like symptom presentation and progression. A set of peptidomimetics which activate the proteasome were developed. The design was based on proteasome-binding fragments of the viral protein HIV-1 Tat (Jankowska, E. et al. Biopolymers 93, 481-495, doi:10.1002/bip.21381 (2010)), which shares a short proteasome binding motif with the 11S/REG/PA28 natural proteasome activator (Huang, X. et al. J Mol Biol 323, 771-782, doi:10.1016/s0022-2836(02)00998-1 (2002)). Since proteasome activated with 11S takes significant part in the cellular immune response, the viral protein uses competition with 11S as a part of its anti-immune response strategy (Huang, X. et al. J Mol Biol 323, 771-782, doi:10.1016/s0022-2836(02)00998-1 (2002)). While Tat1 inhibits the artificially activated core proteasome (Witkowska, J., et al. J Pept Sci 20, 649-656, doi:10.1002/psc.2642 (2014); and Karpowicz, P. et al. PLoS One 10, e0143038, doi:10.1371/journal.pone.0143038 (2015)), its physiological relevance lies in the ability to activate the native latent core (Jankowska, E. et al. Biopolymers 93, 481-495, doi:10.1002/bip.21381 (2010)). A peptidemimetic composed of the 12AA proteasome binding region was generated. A peptide, Gly48-Arg58, is a well-known ‘cell-penetrating-peptide’ with blood-brain-barrier-passing capacity due to its highly positive charge and peculiar structure. The 12AA-residue is not sufficient to carry the transcription-stimulating functions of the full-length HIV-1 Tat protein (Ray, A. S. AIDS Rev 7, 113-125 (2005)). This positioned Tat1 peptide as an attractive lead for design of proteasome agonists with excellent absorption ability. The compositions disclosed herein have an improved proteasome-targeting efficiency and are more stable. Previous work indicated the potential presence of two structural turns (Jankowska, E. et al. Biopolymers 93, 481-495, doi:10.1002/bip.21381 (2010)). Destabilizing the turns by Ala-walking or stabilizing by introduction of synthetic turn-inducers led to the following the pharmacophore: a hook-like structure with a strongly positively charged peptide moiety connected by a β-type turn to short peptide fragment (Karpowicz, P. et al. PLoS One 10, e0143038, doi:10.1371/journal.pone.0143038 (2015)). Synthetic stabilization of the turn bestowed resistance to degradation by the proteasome to the peptidomimetic, TAT1-8,9TOD (Karpowicz, P. et al. PLoS One 10, e0143038, doi:10.1371/journal.pone.0143038 (2015)), which appeared to strongly activate in vitro the “workhorse” chymotrypsin-like activity of both latent 20S and assembled 26S proteasome (
The in vitro results indicate strong activation of the proteasome, thus, the next step was to establish the efficacy of the compounds disclosed herein in an Alzheimer's disease model. The compounds disclosed herein showed increased proteasome activity in flies (
Next, TAT1-8,9TOD was tested. The results showed that treatment of the TET-OFF APPN17-C99 overexpression cell line MC65 reduced Alzheimer's disease-like cell death (
These findings demonstrate the capacity of proteasome augmentation as a germane target for treatment of Alzheimer's disease-like symptoms in a range of model systems. The proteasome activating peptide mimetic TAT1-8,9TOD can be used as pharmacologic treatment. The findings also show that proteasome protective effects stem at least in part from increased degradation of Aβ machinery/substrate.
Experimental Procedures.
Fly Lines and Strain Maintenance. UAS-ProsBeta5 (Staudt, N. et al. PLoS Genet 1, e55, doi:10.1371/journal.pgen.0010055 (2005)) and Elav-GS-GAL4; UAS-hAPP; UAS-hBACE1 (56756) stocks were obtained from the Bloomington Drosophila Stock Center (NIH P40OD018537). The lines were maintained on agar-cornmeal-dextrose-yeast growth media (Ren, C., Finkel, S. E. & Tower, J. Exp Gerontol 44, 228-235, doi:10.1016/j.exger.2008.10.002 (2009)) in a humidified 24° C. incubator with 12:12-hour light:dark cycle. The crosses were set up with female virgins of the respective GAL4 driver line and male UAS-ProsBeta5 or W1118 flies. Progeny were collected within 48 hours of eclosion and allowed to mate on 10% sugar/yeast (SY10) media (Skorupa, D. A., et al. Aging Cell 7, 478-490, doi:10.1111/j.1474-9726.2008.00400.x (2008)) for another 48 hours. After this period, females were separated and sorted into sets of 25 flies per vial containing SY10 media supplemented either with 400 μM mifepristone (RU486) or ethanol vehicle, mixed directly into the food. 8 μM Blue Dye #1 was added to food containing RU486 for the purpose of identification. Carbon dioxide was used to briefly anesthetize flies for sorting. Flies were moved to vials of fresh media every two to three days.
Cell culture. Cells were cultured in EMEM (SK-N-SH), DMEM (MC65) supplemented with 10% heat-inactivated fetal bovine serum and antibiotics (100 U mL−1 penicillin, 100 μg mL−1 streptomycin, and 0.25 μg mL−1 of amphotericin B; Gibco-Invitrogen). Incubators were maintained at 5% CO2, and 37° C. Medium was replaced every 3-4days. For most experiments, cells were seeded at 100,000 cells mL−1 in either 6-well or 96 well plates 24 h prior to assay. In most cases, media was replaced with serum free optimem media 24 h prior to assay.
Transfections and imaging. Cells were seeded at 75,000 cells per well in 6 well plates. They were transfected the day after with 1.4 μg of NSE-PSMB5 vector or NSE empty vector control plus 1 μg of GFP-APP vector per well using Lipofectamine LTX and Plus reagent (Thermofisher #15338030) following manufacturer's instructions. Cells were passaged to a 96 well plates the day after transfection for some experiments. Cells were imaged with the Incucyte system (Sartorius) and images were analyzed with manufacturer's software for GFP Fluorescence intensity normalized by cell confluence.
NSE-PSMB5. A full length mouse PSMB5 plasmid was utilized (MR203485, Origene), PSMB5 was excised removing the Myc-DDK-tag, and cloned into the ShuttleNSE empty vector (50958, Addgene) (Mi, J. et al. PLoS One 8, e83609, doi:10.1371/journal.pone.0083609 (2013)) adjacent to the NSE promoter. The NSE-PSMB5 region was excised and microinjected into (C57BL/6 X SJL)F2 mouse eggs by the University of Michigan Transgenic Animal Model Core. Mice were then bred into a C57BL/6J Background for 3 generations. The mouse is still in a mixed background which may confound some of the outcome measures. To control for this, the experimental comparisons were made between littermates.
Mice. hAPP(J20) (Mucke, L. et al. J Neurosci 20, 4050-4058 (2000); Hsia, A. Y. et al. Proc Natl Acad Sci USA 96, 3228-3233, doi:10.1073/pnas.96.6.3228 (1999); Roberson, E. D. et al. Science 316, 750-754, doi:10.1126/science.1141736 (2007)) and NSE-PSMB5 mice were maintained by heterozygous crosses with C57BL/6J mice (Jackson Laboratories, Bar Harbor, Me.). Non-transgenic littermates were used as controls. Animals were house in ventilated cage racks under with up to 5 animals per cage under 12 hr light/dark cycles at 24° C. Animals received daily monitoring by Laboratory of Animal Research (LAR) staff and were transferred to new cages weekly.
Quantitative PCR. mRNA was isolated using standard Trizol method and cDNA prepared using High-capacity cDNA reverse transcriptase kit (Applied Biosystems). Quantitative PCR was carried out using SYBR Green and normalized to beta-actin.
Plate-based proteasome activity assay. Samples were homogenized by pestle in 100 μL chilled proteasome buffer (50 mM Tris, 5 mM MgCl2, 1 mM DTT, pH 7.4, vortexed and then centrifuged at 21,000 g at 4° C. for 15 minutes and supernatant transferred. Protein content was recorded by Bradford assay and samples diluted as appropriate. In a black 96-well plate, 10 μL of samples were added to 80 μL proteasome buffer supplemented with addition of 5 mM ATP for measuring 26S proteasome activity. Finally, 50 μM Suc-LLVY-AMC fluorogenic substrate in 10 μL proteasome buffer was added to each well to measure chymotrypsin-like activity. The plate was incubated at 37° C. in a SpectrumMax M2 plate reader for four hours with fluorescence measured every 10 minutes with 355 nm excitation and reading 460 nm emission. Total proteasome activity per sample was defined as the gradient of the linear trendline over this incubation period.
Drosophila lifespans. Flies were transferred to fresh media and survival scored every two to three days. dLife software (Linford, N. J., et al. J Vis Exp, doi:10.3791/50068 (2013)) was used to record survival and to compare median and maximum lifespan via Logrank analysis. Vials were randomized in terms of tray position and semi-blinded to reduce impacts of environment or investigator bias.
Olfactory aversion training. Experiments were performed broadly (Malik, B. R. & Hodge, J. J. J Vis Exp, e50107, doi:10.3791/50107 (2014)). Animals were exposed (via an air pump) in alternation to two neutral odors (3-octanol and 4-methylcyclohexanol, prepared as a 1/10 dilution in mineral oil) for 5 minutes under low red-light and a 100V 60 Hz shock was applied during exposure to one of the two odors. The odor associated with the electric shock was alternated between vials. After three training rounds per odor, animals were given one hour to recover then placed in a T-maze (Celexplorer labs) with opposing odors from either side. Flies were allowed two minutes to explore the maze after which the maze sections were sealed and the number of flies in each chamber scored.
Spontaneous activity and circadian rhythm. Spontaneous activity was monitored using a Trikinetic activity monitor, in which vials containing 20-25 flies were secured and activity recorded in a humidified 24° C. incubator with 12:12-hour light:dark cycles as described herein. Flies were allowed to acclimate for 8 hours prior to data collection. Activity was averaged for each twelve-hour cycle and normalized per fly.
Cell viability. Cell maintained in a clear 96 well plate. On the day of assay, 10 μl of WST-1 reagent (11644807001, Sigma Aldrich) was added to each well and cells incubated in a 37° C. 5% CO2 incubator for 2-4 hours. Absorbance was measured at 450 nm using a gemini series spectrophotometer.
Morris water maze (MWM) (Morris, R. J Neurosci Methods 11, 47-60 (1984); Galvan, V. et al. Reversal of Alzheimer's-like pathology and behavior in human APP transgenic mice by mutation of Asp664. Proc Natl Acad Sci USA 103, 7130-7135, doi:10.1073/pnas.0509695103 (2006); Butterfield, D. A. et al. Free Radic Biol Med 48, 136-144, doi:10.1016/j.freeradbiomed.2009.10.035 (2010); and Pierce, A. et al. J Neurochem 124, 880-893, doi:10.1111/jnc.12080 (2013)). This test provides measures of hippocampal-dependent spatial learning and memory. Animals are given a series of 4, 1 min trials, 20-30 min apart, per day for 5 days to find a submerged platform (˜1.5 or 1 cm below water level respectively) in a large tank (210 and 120 cm in diameter respectively) filled with opaque white-colored water at 24.0±1.0° C. surrounded by panels with geometric black and white designs that serve as distal cues. At the end of training, a probe trial in which the platform is lowered so that it is not available is administered to measure retention of the former platform location. The time each animal spends in the former location of the platform, the number of passes over that location provide a measure of memory. At the end of the probe trial, the platform will be raised to its previous location to maintain response-reinforcement contingency. Time-at-testing for groups will be alternated daily. Intertrial time will be ˜30 min. On week 2 of training, reversals are performed, followed by a probe trial. Data is collected using TopScan (CleverSys) or Noldus EthoVision by operators blinded to genotype and treatment.
Y maze. Working memory is assessed by placing animals in a Y-shaped maze made of black Plexiglas with 3 arms, with equal angles between all arms. Each animal is placed in a pseudo-randomized arm of the maze and allowed to move freely around the apparatus, while the sequence and number of arm entries for each animal per minute for a 5-min period is recorded using TopScan (CleverSys) software. The percentage of movements in which the three arms were represented (ABC, CAB, or BCA, but not BAB) is calculated, as well as alternations among arms, to estimate short-term memory of the last arms entered. The total number of possible alternations is the number of arm entries minus two. Additionally, the total number of arm entries is an indicator of activity.
Novel object recognition test. To measure recognition of a previously encountered object, animals are placed in an opacified rat cage with bedding for 10 min. The following (training) day, mice are returned to the chamber, which now contains two identical objects, and allowed to explore the arena for 5 minutes. Percent of time exploring each object is recorded using TopScan. During testing (4 hours after training) one of the objects in the box is replaced with a new object and the side of the replaced object randomized amongst animals. Mice are given 5 mins to explore the two objects, and percent time exploring each object is recorded using TopScan. A discrimination ratio calculated as (tnovel−tfamiliar)/(tnovel+tfamiliar) is used as a measure of retention of the priorly encountered object (positive and negative discrimination ratio values indicate a preference for exploration of the novel and familiar objects, respectively).
Statistics. Morris water maize was evaluated by two-way ANOVA followed by Tukey posthoc test. Y-Maze was evaluated by Two-way ANOVA followed by Bonferoni posthoc test. Olfaction Aversion Training was evaluated by Chi Squared. Lifespan analyses were evaluated by Log Rank investigation. Where not states statistical evaluations were performed by Student's T-Test.
Abstract. Proteasome is an element of controlled proteolysis responsible for catabolic arm of proteostasis. A proteasome can be a target for inhibition of its peptidolytic activities. This mechanism is utilized in clinical treatment of blood cancers because of a comfortable window of proteasome dependency of normal and cancerous cells. The latter are often addicted to proteasome activity as a motor of their high proliferative and metabolic capacity. The results described herein show that substantial augmentation of proteasome activity with specific pharmacological interventions can be achieved with Tat peptides leading to positive responses in symptoms of Alzheimer's disease in fly and mouse models. Described herein, is the molecular basis of proteasome activation with Tat derived peptides. It was tested whether an activation anchor responsible for upregulation of catalytic activity via allosteric signaling is connected via a β turn inducer to a specificity clamp that binds on an α surface of 20S proteasome achieving the proper location on α1 subunit. Elements that potentially control these effects were evaluated and mechanistic consequences of Tat binding to the α3 groove of proteasome is discussed herein.
Docking of Tat-TOD scaffold to the α ring of 20S proteasome shows preferential peptide binding in a groove between α1 and α2 subunits. The activity anchor penetrates deep between the subunits, whereas the specificity clamp is positioned on the surface of α1 subunit by the β turn. A block scheme of Tat1 derivatives showing position of the activity anchor connected to the specificity clamp through a β-turn. Tat-Den is built from three identical blocks playing roles of specificity clamps and activity anchors.
Tat proteins. Full length HIV-1 Tat protein stimulates transcription from a viral promoter by binding to the TAR hairpin of the RNA transcript. It functions as a transcriptional transactivator that increases the production of the full length viral RNA. Binding to TAR is mediated by a 10 residue long basic region of Tat that maps in part to Tat1 peptide. However, for regulatory function such as binding to elements of the transcriptional complex, Tat protein requires its 47 long N-terminal domain encompassing an acidic and cysteine rich domains and hydrophobic core (Ray A S. AIDS Rev [Internet]. 2005; 7(2):113-125). The basic domain has a helical structure when built into Arginine Rich Motif RNA binding protein (ARM) such as Tat. This structure is apparently not preserved in the excised peptide. On this basis, it was assumed that this important function of Tat protein is not sustained in Tat1 peptide.
Tat protein fragments. Conformationally constrained peptides, in context of proteasome binding and regulation.
Means to activate proteasome (Myeku N, Duff K E. Trends Mol Med [Internet]. Elsevier; 2018 Jan. 11; 24(1):18-29). (1) Natural activators of proteasome: phosphorylation, inhibition of DUBs (USP14 inhibitors) (Peth A, et al. Mol Cell. 2009 December; 36(5):794-804; and Lee B-H, et al. Nature [Internet]. 2010 September [cited 2015 Feb. 13]; 467(7312):179-184), clearance (Boland B, et al. Nat Rev Drug Discov [Internet]. 2018 Aug. 17; 17:660).(2) Natural protein modules—activators (e.g., PA28/REG/11S, PA200/Blm10, 19S). (3) Detergent (low concentration of sodium dodecyl sulfate; SDS). (4) Synthetic small molecule activators.
Incorporation of Tic (1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) and Oic (octahydroindole-2-carboxylic acid) residues into bradykinin sequence was applied to achieve structurally constrained peptides for study on a bradykinin receptor (Chakravarty S, et al. J Med Chem [Internet]. 1993 Aug. 20; 36(17):2569-71; and Kyle D J, et al. J Med Chem [Internet]. 1991 August; 34(8):2649-53). Extensive studies were carried on antimicrobial peptides that incorporated Tic Oic moieties showing promising actions toward select agents (Hicks R P. Bioorg Med Chem [Internet]. 2016; 24(18):4056-4065).
Application of β turn inducers to disrupt protein-protein interactions was explored for example in the case of a tyrosine kinase receptor (Burgess K. Acc Chem Res [Internet]. 2001 October; 34(10):826-35; and Larregola M, et al. J Pept Sci [Internet]. 2011; 17(9):632-643).
Conformational analysis of the Tic containing tripeptide antagonist of opioid receptor showed that L and D variants of the peptide always produced compact structures but pointing at the opposite site of the Tic residue (Wilkes B C, Schiller P W. Biopolymers [Internet]. 1994 September; 34(9):1213-1219). This change in the structure produced highly specific antagonists of δ or μ receptors, respectively. Tic is also used as a substitute for a planar amino acid such as tryptophan in tetrapeptide as a ligand of melanocortin receptor (Schlasner K N, et al. Molecules [Internet]. MDPI; 2019 Apr. 13; 24(8):1463).
Results and Discussion. The tested peptides (
Tat1 (GRKKRRQRRRPS; SEQ ID NO: 1) activated 20S proteasome 7 fold and 2 fold 26S proteasome (Table 1). Surprisingly, an AC50 parameter (a peptide concentration at which the half of maximum activation effect was measured) was lower for 26S than for 20S proteasome (Table 1). Substitution of a single residue of Tat1 with Ala along the whole length of the sequence showed a weak decrease of activating capabilities of ChT-L activity. A substantial drop of this potential was noted when two consecutive residues were substituted with Ala residues at positions from 3 to 6. Moreover, an elongation of the Ala stretch to 3 residues led to a complete abrogation of proteasome activation (
These observations were further confirmed by the docking of Tat-TOD scaffold to the α ring of 20S proteasome that shows preferential peptide binding in a groove between α1 and α2 subunits (
Next, Aib-Gly was introduced as a turn inducer at positions 8,9. This modification led to formation of a superior activator of both 20S and 26S proteasome with AC50 below 200 nM and 11 fold activation for 20S. The replacement of the C terminal (R-P-S; 10-12) sequence with a reversed N-terminal 1-8 sequence (Tat5-8,9Aib), created a surprisingly excellent activator slightly less potent than Tat1-8,9Aib. These results show that a relatively slight stiffening of the peptide with the Aib-Gly moiety improves peptide capability to interact with binding site. The lack of the specificity clamp (RPS) does not influence AC50, although it diminished the activating potential slightly.
These peptides competed with pRpt3 peptide (KDEQEHEFYK; SEQ ID NO: 2) for binding site, a 10 residue C-terminal fragment of Rpt3 protein which forms with other 5 ATPases a ring on the α face of 20S proteasome responsible for unfolding and threading substrates into the axial channel of the protease.
To determine if a simplified sequence of Tat1 can retain activating potential, TO peptides decorated with 3 lysines or 3 alanines on its both sides were prepared. The 3A-TO-3A peptide was totally inactive, whereas 3K-TO-3K retained substantial activating capabilities but with a disappointingly high AC50. This peptide is also a poor competitor with pRpt3 peptide that binds into the same pocket. Surprisingly, an additional 3K sequence but decorating a benzoyl moiety (creating Tat1-Den with three 3K peptides in a star like orientation) produced one of the best proteasome activators. It was concluded that a three-lysine sequence is sufficient to activate proteasome, however, activation occurred in the presence of an actual clamp formed by two other 3K sequences (Table 1,
Titration of latent 20S proteasome with most of the tested peptides presented a clear maximum after which a decrease in the activation was noted. Based on the fitted traces it seems that the activation may never drop to 100% since it would call for physically unachievable peptide concentrations. Tat-Den was a sole exception to this rule and likely reached a saturating effect. This type of response was characteristic for 26S proteasome with the following exceptions: Tat1-4,5TO and Tat1-8,9TO. The titration traces resembled in these cases those observed with 20S proteasome. It was then tested whether the maximum peak type response may correspond to the effect of occupancy at other binding sites where affinity or specificity is substantially lower. Likely, it does not correlate with potential competition with the substrate since Tat1 is digested by 20S proteasome and Tat1-8,9TOD is resistant to degradation.
Abstract. The proteasome is an important element of controlled proteolysis, responsible for the catabolic arm of proteostasis. By inducing apoptosis, small molecule inhibitors of proteasome peptidolytic activities are successfully utilized in treatment of blood cancers. However, the clinical potential of proteasome activation remains relatively unexplored. Described herein are short TAT peptides derived from the HIV-1 Tat protein and modified with synthetic turn-stabilizing residues as proteasome agonists. Molecular docking and biochemical studies point to the α1/α2 pocket of the core proteasome α ring as the binding site of TAT peptides. It was tested whether the TATs' pharmacophore consists of an N-terminal basic pocket-docking “activation anchor” connected via a β turn inducer to a C-terminal “specificity clamp” that binds on the proteasome a surface. By allosteric effects—including destabilization of the proteasomal gate—the compounds substantially augment activity of the core proteasome in vitro. Significantly, this activation is preserved in the lysates of cultured cells treated with the compounds.
Introduction. As the central protease of the ubiquitin-proteasome pathway, the proteasome has long been considered an attractive target for drugs potentially affecting multiple aspects of cell physiology [1]. Indeed, small molecules targeting the proteasome have entered the clinic with great success [2]. However, their scope at present is very limited: the proteasome-modifying compounds currently approved or clinically tested as drugs are competitive inhibitors and are used to treat advanced blood cancers [1,3]. Turning to the opposite side of pharmacological intervention into the proteasome: augmentation of catalytic activity. Since dysfunction of proteasome-mediated controlled protein degradation is a hallmark of both cellular aging [4,5] and neurodegenerative diseases [6-9], enhancement of the enzyme's activity should be considered an attractive therapeutic option. The complex structure of the catalytic core 20S proteasome (the “core particle”;
Described herein are a series of short, modified peptides based on the basic domain of the viral Human Immunodeficiency Virus-1 (HIV-1) Transcriptional Activator TAR (Tat) protein (
Results and Discussion. Design of TAT Peptides. A set of proteasome agonists were developed and designed to activate the proteasome in vitro, to support blood-brain-barrier (BBB) transition, and to stably augment the proteasome in the nervous system. This design was based on a basic domain of the Human Immunodeficiency Virus-1 (HIV-1) Transcriptional Activator TAR (Tat) protein 48GRKKRRQRRRPS59 (TAT1 (SEQ ID NO: 1); (1)), which contains a proteasome-binding RTP (REG/Tat-proteasome-binding site) motif [26]. This RTP motif is shared with subunits of the endogenous PA28/REG protein (proteasome activator/regulator with 28 kDa subunits; 11S), which targets pockets on the core proteasome α face [21] (
As the next step, the effects of introducing TO (Tic: L-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid, Oic: Octahydroindole-2-carboxylic acid), TOD (Tic D-Oic) or DABA (3,5-diaminobenzoic acid) as synthetic turn inducers in the important positions of TAT1 were assessed. Since the putative turn was flanked by predominantly basic sequences, the robustness of the design was explored by simplifying the Arg and Lys stretches to triple-Lys (Table 2).
TAT Peptides Activate the ChT-L Peptidase of the Human Proteasome in vitro and in Cellulo. As summarized in Table 3 and demonstrated in
Interestingly, two types of titration profiles with TAT peptides were observed (
Among the three proteasomal cleavage specificities, the “workhorse” ChT-L peptidase was significantly affected, as demonstrated for selected compounds (
Taken together, a structural constraint induced by a single turn placed close to the C-terminus and selected basic residues were important to achieve the strongest activation at the lowest peptide concentration.
The strong in vitro performance of TAT peptides led to the testing of selected activators on proteasome activity in cultured cells. Human neuroblastoma SK-N-SH (ATCC/American Type Culture Collection HTB-11) line was chosen as a representative for neural cells as these may become future targets of proteasome agonists in treatment of neurodegenerative diseases with compromised proteasome performance. None of the tested compounds at 1 μM significantly affected proliferation and viability of the cells after 24 h of treatment (see caption of
The α1/α2 Inter-Subunit Pocket on the a Face of Core Proteasome is the Primary Binding Site of TAT Peptides. The Binding Changes Conformational Equilibrium of the Proteasome's Gate. To gain mechanistic insight and to aid further modifications of the compounds, molecular docking of (5) to the human core proteasome was performed using Rhodium® software suite (Southwest Research Institute; SwRI; San Antonio). In its docking approach, different locations on the surface were seeded with 104 to 105 copies of a ligand conformer, generating trial candidate binding configurations. The inhibitor's seeded configurations were allowed to move independently over the surface, optimizing the coordinates of the binding location along a path to a local energy minimum on the surface. Certain ligand molecules starting at different locations converged to several common locations. The docking was performed in two steps. First, a square-well interatomic potential for docking, similar to the approach published by Vakser [33,34] was used for the primary docking. Next, the identified docking pose candidates were screened with a second tier docking for pose refinement, typical for the traditional docking codes.
As mentioned herein, the binding pockets on the α face accept “anchors” from natural protein ligands of the 20S core [25,36,37]. Certain anchoring peptides are known to interact with the α face in trans, most notably C-terminal “tails” of Rpt ATPase subunits of the 19S complex bearing the “HbYX” (hydrophobic-Y-any amino acid) C-terminal motif [38]. The 10-residue Rpt-derived C-terminal “tail” peptides (“Rpt peptides”) can be used as competitors with the Rpt subunits or with small allosteric ligands [19,38,39]. Importantly, the Rpt peptides interject between the subunits with their C-termini, whereas TAT peptides, according to the modeling, use their N-termini for this purpose. To test the specificity of interactions between TAT compounds and the α face, competition experiments were performed. The 20S core was challenged with selected TAT compounds after treatment with Rpt peptides. Peptides of Rpt2 (QEGTPEGLYL; SEQ ID NO: 10), Rpt3 (KDEQEHEFYK; SEQ ID NO: 11), Rpt5 (KKKANLQYYA; SEQ ID NO: 12) and Rpt6 (KNMSIKKLWK; SEQ ID NO: 13) subunits were selected, docking in α3/α4, α1/α2, α5/α6 and α2/α3 pockets, respectively. Tails of Rpt2, 3, and 5 display the canonical HbYX motif, whereas the LeuTrpLys C-terminus of Rpt6 may be considered “pseudo-HbYX”, with a bulky Trp replacing Tyr. Results of the competition experiments are presented as radar plots in
The putative binding site corresponds to one of the natural “anchoring spots” on the a face of the core proteasome. The inter-subunit pockets are used to attach regulatory proteins: PA28/REG (all pockets), PA200 (proteasome activator of 200 kDa; α5/α6 pocket), as well as the Rpt subunits of the 19S particle (all pockets except α6/α7 and α7/α1) [26, 36, 40]. Peptide-activators of the core that utilize the structure of docking fragments of these natural activators were found to bind into the α5/α6 pocket, while a small molecule activator TCH-165 reportedly preferred the α1/α2 site [19,20,41]. Binding of these ligands resulted in opening or at least destabilizing the gate in the center of the α face, as revealed by crystal structures, cryoEM (cryo-electron microscopy) and atomic force microscopy (AFM) imaging [19,20,25,40-43]. Gate opening is prerequisite for the uptake of substrates and release of products from the concealed catalytic chamber of the core proteasome (
In the light of significant proteasome-enhancing effects of TAT peptides observed both in cellulo (
Materials and Methods. Synthesis of Selected Peptides. Synthesis and properties (1) have been described[22], (2)-(5) and (9) have been described[24]. Synthesis and purification of (6) and (7) followed the procedures described in [24]. The peptides have been purified to at least 99% of purity.
Synthesis of TAT1-Den Peptide (8). Synthesis of (8) was performed on 0.25 mmol scale, according to Fmoc/tBu methodology, in a Liberty Blue™ automated microwave synthesizer (CEM Corporation). The TentaGel PHB resin was used as a solid support with an initial capacity of 0.23 mmol/g.
The following Fmoc-protected amino acid derivatives were used in the synthesis: Fmoc-Lys(Boc)-OH and Di-Fmoc-3,5-diaminobenzoic acid.
The first amino acid, Fmoc-Lys(Boc)-OH, was attached to the solid support using 1-methylimidazole (MeIm) and 1-(2-mesitylenesulfonyl)-3-nitro-1H-1,2,4-triazole (MSNT). 5 eq. of Fmoc-Ser(t-Bu)-OH (relative to the resin capacity) was dissolved in dichloromethane (DCM) with addition of a few drops of tetrahydrofuran. Next, 3.37 eq. of Melm and 5 eq. of MSNT were added, and the mixture stirred for 15 min. The mixture was then transferred to a round-bottom flask containing the resin swollen in DCM. The mixture was flushed with argon and left on a vertical shaker for 2 h, then the peptidyl resin was drained, washed and dried in a vacuum desiccator. The resin loading was determined as follows: a few milligrams of the dry peptidyl resin were transferred to a 2 mL test tube, 1 mL of 20% piperidine in dimethylformamide (DMF) was added, and the tube was shaken for 30 min. Then, the mixture was transferred to a 25 mL volumetric flask and filled with methanol. The solution was transferred to a quartz cuvette and the loading of the peptidyl resin was calculated from measurement of the absorbance at λ=301 nm.
The Fmoc-Lys(Boc)-resin was transferred into a reaction vessel and soaked prior the synthesis cycle in DMF for 30 min. In the next step, the Fmoc group was removed (deprotection cycle) using 30% solution of piperidine in DMF. The mixture was irradiated for 15 s with a 167 W microwave power (temperature 75° C.), then with a power of 31 W for 50 s (temperature in the range 89-90° C.). The solid support was then drained and washed four times with DMF, and the deprotection cycle was repeated. Next N-terminally protected amino acid was attached, using as a coupling solution a mixture of 0.5 M N,N′-diisopropylcarbodiimide (DIC) and 1 M Oxyma pure (racemization suppressor) in DMF. The coupling reaction step was carried out with a four-fold excess of an amino acid derivative, calculated based on the initial capacity of the solid support. The efficiency of this step was enhanced with microwave radiation of 162 W for 15 s (temperature 75° C.), then 33 W for 110 s (temperature in the range of 89-90° C.). The peptidyl resin was then drained and the coupling cycle was repeated. Next, the 30% piperidine solution in DMF was added to de-protect the N-terminal amino group. This step was carried out in the same conditions as described herein. Double coupling cycles with the use of DIC/Oxyma reagents were performed till the attachment of the third Fmoc-Lys(Boc)-OH residue (fifth residue in the sequence). Coupling of the fourth residue in the sequence (Di-Fmoc-3,5-diaminobenzoic acid) was carried out with a three-fold excess of the amino acid, calculated based on the initial capacity of the solid support. The efficiency of this step was enhanced by applying microwave irradiation (85 W for 60 s, temperature 40° C., then 25 W for 540 s, temperature in the range of 63-65° C.). The peptidyl resin was then drained and the coupling cycle was repeated. The residue was deprotected under the same conditions as described herein, with triple repetition of the cycle. Starting from the third residue in the sequence, the coupling reagents were switched to 1-Cyano-2-ethoxy-2-oxoethylidenaminooxy) dimethylamino-morpholino-carbenium hexafluoro phosphate COMU. The N-protected amino acid derivatives were coupled with the use of a three-fold excess of an amino acid, calculated based on the initial capacity of the solid support, 2.9-fold of COMU and 5.8-fold of diisopropylethylamine. The coupling efficiency was enhanced by applying microwave irradiation of 120 W for 60 s (temperature 60° C.), then 25 W for 30 s (temperature in the range of 78-80° C.). The peptidyl resin was then drained and the coupling cycle was repeated. The deprotection reagents and protocols were not changed. After completion of the synthesis, the peptidyl resin was washed four times with DMF, then three times with methanol and left overnight to dry in a vacuum desiccator.
Peptide Cleavage from the Solid Support. The peptide was cleaved from the solid support, along with the removal of protecting groups from amino acid side chains, using the mixture of trifluoroacetic acid (TFA), triisopropylsilane and water (92:4:4, v/v/v). The reaction was carried out for two hours on a laboratory shaker. The resin was then drained under the reduced pressure on a filter funnel and the filtrate was concentrated to a volume of about 2 mL with a vacuum evaporator. The remaining filtrate was treated with diethyl ether (cooled to about 4° C.). A white precipitate was obtained and centrifuged in a centrifuge tube for 15 min (4500×g). The supernatant was decanted and the pellet was treated with another portion of diethyl ether. The precipitate was washed this way three times, and then dried in a vacuum desiccator. The obtained crude product was dissolved in water and freeze-dried.
Purification. The compound was purified using a reversed-phase HPLC (RP-HPLC). The crude product was dissolved in water and injected onto a Jupiter® Proteo C12 semipreparative column (21.2 mm×250 mm, 90 Å, 4 μm; Phenomenex). The chromatographic separation was carried out using a linear gradient of 1-100% B over 75 min, and the eluents: A: 0.1% TFA in H2O and B: 0.1% TFA, 10% methanol in H2O. The eluent flow rate was 15 mL/min, UV detection at λ=223 nm. After the collection of the main fraction, solvents were evaporated using a vacuum evaporator. Next, the fraction was dissolved in water and injected onto the same semipreparative column. The second purification was carried out in a linear gradient of 1-40% B over 75 min with the eluents: A: 0.1% TFA in H2O and B: 0.1% TFA in 5% acetonitrile (ACN) in H2O. The eluent flow rate was 15 mL/min, UV detection at λ=223 nm.
Characterization of the Product with HPLC and Mass Spectrometry. The product was subjected to chromatographic analysis using RP-HPLC. Conditions: chromatographic column: Kinetex 2.1 mm×100 mm, 100 Å, 2.6 μm (Phenomenex); eluents: A: 0.1% TFA in H2O, B: 0.1% TFA, 80% ACN/H20; flow rate 0.5 mL/min; UV detection at A=223 nm; gradient 5-45% B over 7 min, temperature of an oven 40° C., Rt=4.42 min. The calculated molecular weight of the compound was confirmed using a LC-MS IT-TOF (Shimadzu) mass spectrometer. Peptide was injected directly into the ion source. Theoretical average molecular weight of the compound: 1305.2 Da, obtained m/z: 1304.81 [M]+.
Determination of Proteasome Activity. Human housekeeping core (20S) proteasome purified from erythrocytes was purchased from Boston Biochem, Inc. (Cambridge, Mass.) or from Enzo Life Sciences, Inc. (Farmingdale, N.Y.). Multiple batches of the proteasomes were used and performed reproducibly. The stock proteasome was diluted to 0.2 mg/mL working solution in “dilution buffer” (50 mM Tris/HCl, pH 8, 20% glycerol). The following model peptide substrates, releasing fluorescent 7-amino-4-methylcoumarin (AMC) reporter group after cleavage, were used: succinyl-LeuLeuValTyr-AMC (SEQ ID NO: 14) (for the ChT-L peptidase; SucLLVY-AMC; Bachem Bioscience Inc., Philadelphia, Pa.), butoxycarbonyl-LeuArgArg-AMC (T-L; Bachem Bioscience Inc., Philadelphia, Pa.) and carbobenzoxy-LeuLeuGlu-AMC (PGPH; Enzo Life Sciences Inc., Farmingdale, N.Y.). The substrates were used at concentration of 50 μM (ChT-L) or 100 μM (T-L, PGPH). Free AMC (Sigma-Aldrich, St. Louis, Mo.) was used as the standard. The C-terminal peptides derived from Rpt2, Rpt3, Rpt5 and Rpt6 were synthesized (standard solid-phase peptide chemistry) and purified to at least 98% purity by GenScript (Piscataway, N.J.). The TAT peptides, Rpt peptides (except Rpt6) and the peptide substrates were dissolved in anhydrous dimethylsulfoxide (DMSO; Sigma-Aldrich, St. Louis, Mo.) and such stock solutions were stored at −20° C. The total concentration of DMSO in final reaction mixtures never exceeded 3% (vol/vol). The Trp (tryptophan)-containing Rpt6 peptide was dissolved in ultrapure water and stored at −20° C., protected from light. The reaction was carried out in 96-well plates, in 100 μL of reaction mixture that consisted of 45 mM Tris/HCl, pH 8, 100 mM KCl, 1 mM EDTA (reaction buffer) and a fluorogenic peptide substrate, to which 200 ng (nearly 0.3 nmol) of proteasome were added. The addition of KCl/EDTA (ethylenediaminetetraacetic acid) to reaction buffer assured latency of the core proteasome. The proteasome was preincubated with a substrate for 10 min at room temperature, then 1 μL of DMSO or a desired concentration of a TAT peptide in 1 μL of DMSO were added. After mixing, the plate was transferred to a Fluoroskan Ascent plate reader (Thermo Fisher Scientific Inc., Waltham, Mass.) for 1 h (37° C.), with fluorescence readouts once per minute [54]. To test the competition with Rpt derived peptides, the Rpt peptide (1 μM) was added before the TAT peptide to the reaction mixture. The reaction rates were calculated from a linear segment of kinetic curves constructed from measurements in 1-min intervals. Reaction rates were calculated using a linear fit performed with the Slope Analyser and Enzyme Kinetics applications launched within Origin Pro 2019 (OriginLab Corporation, Northampton, Mass.). Specific ChT-L activity of the latent control 20S proteasome ranged from 3.4 to 6.0 nanomoles of AMC product released by 1 mg of 20S per minute (4.2±0.8; n=26). The data are presented as mean±SD from at least three independent experiments.
Cell Culture. Human SK-N-SH neuroblastoma cell line (ATCC® HTB-11™ American Type Culture Collection; Manassas, Va.) were cultured according to ATCC specifications (EMEM, 10% heat-inactivated FBS) The cells at passage 2-4 were treated with 1 μM TAT peptides or the DMSO vehicle diluted with the medium 1: 1000, for 24 h. The content of live cells was determined by the Trypan Blue-exclusion assay. The cells were harvested, washed twice in PBS, resuspended in dilution buffer (as described herein) and stored in −80° C. To prepare lysates, the thawed preparations were vortexed with glass beads and centrifuged for 5 min 5,000×g (4° C.). The supernatant was centrifuged for 20 min 14,000×g (4° C.). The resulting supernatant—“crude lysate” was diluted to 1 mg/mL of total protein with dilution buffer. 1 μg of lysate per assay (reaction buffer: 50 mM Tris/HCl pH 8, 0.1 mM MgCl2, 0.2 mM ATP, 0.1 mM dithiothreitol, 50 μM Suc-LLVY-AMC (SEQ ID NO: 14)) was used for determination of ChT-L activity in a 96-well format, as above. Activities in lysates were also tested in the presence of a high concentration (1 μM) of a strong competitive proteasome inhibitor Bortezomib. The resulting negligible degradation of the model substrate in the presence of bortezomib indicated that proteasome is the sole source of activity observed in the lysates.
Molecular Docking. Relative binding locations of (5) were determined on the surface of human core proteasome represented by crystal structure 5LE5 [35]. The 3D structures of (5) were used [24]. Docking poses were determined with Rhodium® 3.9 in four separate docking trials, as described in Results. For each trial, poses were generated on a grid covering the surface of the protein model, with 72 trial states per grid point, with resolution of 1.7 Å. Forty poses with the maximum cavity-filling scores were prepared and analyzed with PyMol v.1.5.0.5 (Schrodinger LLC, New York, N.Y. [55-57]). The top-ranking pose with ligand-proteasome contacts along both activation anchor and specificity clamp is presented.
Atomic Force Microscopy (AFM) Imaging. Single molecules of 20S proteasomes were imaged in tapping (oscillating) mode in liquid, with a scanner E of the Multimode Nanoscope IIIa (Bruker Inc., Santa Barbara, Calif.) [45]. The proteasomes were electrostatically attached to a muscovite mica substrate, covered with imaging buffer (5 mM Tris/HCl, pH 7) and scanned using cantilevers with the spring constant of 0.35 N/m from the SNL (Sharp Nitride Lever) probes (Bruker Inc., Santa Barbara, Calif.) tuned to 9-10 kHz. The amplitude set-point in the range of 1.5-2.0V, drive voltage of 300-500 mV and 3.05 Hz scanning rate were used. Scans of 1 μm2 fields (512×512 pixels) were collected in height-mode. The images of fields typically contained several dozens of top-view (“standing”) 20S proteasome particles. The gate status was deduced from a profile of raw height values of pixels measured by a probe scanning across the single proteasome particles [20,39]. In short, under the employed scanning conditions the proteasome a face with the central gate area was completely rendered by a six-pixel (11-12 nm) scan-line fragment. Numerical values of the height of particles of raw (after standard flattening) images were collected with a practical vertical resolution reaching 1 Å. When this scan-line presented a local minimum (a central dip), the particle was classified as containing the open gate. The particle was classified as an intermediate conformer when a plot of height values presented a concave function without a local minimum. When the function was convex, the particle was classified as containing the closed gate. The “events” of gate opening/closing were analysed for scans of distinct particles as well as multiple scans of the same particles.
Statistical Analysis. Experiments were performed at least in three independent replicates. The results are presented as a mean±SD. A two-tailed t-test was applied to compare the means. The comparisons were allowing for unequal variances with a Welch correction. Abundance of proteasome conformers was compared with the chi squared test and two-sample proportion test. A significance level was set at 0.05. Statistical analysis was performed using statistical procedures offered by OriginPro 2019 (OriginLabs, Northampton, Mass.). Reaction rates were calculated from a smoothed linear segment of kinetic traces using OriginPro 2019. Response curves (activity vs. compound concentration) were fitted with a nonlinear fitting application of OriginPro 2019. The AC50 and maximum activation fold was calculated based on the equations implemented to fit the response curves.
The half-life of Tat1 8,9 TOD in serum was about 2 hours (
Purified human 20S and 26S proteasomes were separated on non-denaturing polyacrylamide gel. The gel was overlayed with reaction buffer containing 100 microM fluorogenic peptide substrate Suc-LLVY-MCA (SEQ ID NO: 14) and 1% of vehicle solvent (DMSO) or the substrate and 1 microM Tat1 8,9 TOD. The gel was photographed after 15 min of incubation and then stained for the total protein content with Coomassie Brilliant Blue, and photographed.
The compounds were tested as follows: in neuroblast MC65 cell culture model with overexpressed C99 fragment of amyloid precursor protein (APP) upon tetracycline withdrawal or with external APP added; and in fruit fly (D. melanogaster) model of AD with overexpressed APP and BACE1. The compounds (1 μM) were mixed with food. Flies were trained to recognize “positive” and “negative” odors (olfaction aversion). The compounds were also treated in hAPP (J20) mice which overexpress a familial variant of APP. The compounds were injected for 14 days (1 mg/kg). Novel Object Recognition assay was used to test learning and memory.
The compounds were also tested in vitro with purified human housekeeping core proteasome, including competition of 1 μM mimetics with 1 μM peptide fragments of a face-docking Rpt subunits of 26S proteasome.
Single-molecule Atomic Force Microscopy (AFM) performed with native 20S particles.
Molecular docking studies were performed with Rhodium® (SwRI).
The results are shown in
This application claims the benefit of U.S. Provisional Application No. 62/900,217, filed Sep. 13, 2019. The content of this earlier filed application is hereby incorporated by reference herein in its entirety.
This invention was made with government support under grant number AG061051 awarded by the National Institutes of Health. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/050428 | 9/11/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62900217 | Sep 2019 | US |
