Patent Application
20230165975
This application claims priority from GB2004498.8 filed 27 Mar. 2020, the contents and elements of which are herein incorporated by reference for all purposes.
The present invention relates generally to methods and materials involving gene products that are expressed in an activity-dependent manner, which can be used in treating neurological disorders, such as epilepsy.
Neurological circuit disorders, characterized by abnormal firing of neurons, account for an enormous burden to society and are inadequately treated with drugs. For instance, epilepsy affects up to 1% of the population. Of these sufferers, 30% are refractory (“pharmacoresistant”) to pharmacological treatment, and surgical resection of the brain area where seizures arise (the epileptogenic zone) remains the best hope to achieve seizure freedom. However, such surgery is unsuitable for many due to risk of damage to eloquent regions of the cortex or white matter pathways involved in functions such as memory, language, vision or motor control (Kwan, P. et al (2011), N. Engl. J. Med. 365, 919-926; Picot, M.C. et al (2008), Epilepsia 49, 1230-1238).
New anti-epileptic drugs have had little impact on refractory epilepsy and people with uncontrolled seizures continue to experience co-morbidities, social exclusion, and a substantial risk of sudden unexpected death in epilepsy (SUDEP). Refractory epilepsy is mostly focal (that is, characterized by seizures arising from the epileptogenic zone) but primary generalized epilepsy can also be resistant to pharmacotherapy.
Although surgical resection of the epileptogenic zone can result in seizure freedom, it is unsuitable for 90% of people with refractory epilepsy. Furthermore, the extent of surgical resection is limited by risk of irreversible neurological deficit, meaning that many patients undergoing surgery continue to have seizures. Minimally invasive ablation procedures using lasers have a role in targeting inaccessible deep structures in the brain but are also limited by risk of damage to neighbouring structures. Deep brain stimulation and other neuromodulatory treatments are of limited effectiveness.
Gene therapy is a promising candidate as a rational replacement for surgical treatment of pharmacoresistant focal epilepsy. Examples include overexpression of neuropeptide Y and Y2 receptors (Woldbye et al, 2010), Kv1.1 overexpression (Wykes et al, 2012; Snowball et al. 2019; WO2018/229254); chemogenetics using designer receptors exclusively activated by designer drugs (DREADDs), e.g. hM4Di (Katzel, et al, 2014), and use of the enhanced glutamate-gated chloride channel eGluCI (Lieb et al, 2018).
However, current experimental gene therapies are based on either the permanent modification of neuronal excitability (neurotransmitter, ion channel or receptor overexpression) or the exogenous delivery of light or chemicals to achieve on-demand modulation of neuronal activity (optogenetics and chemogenetics). These approaches have limitations, due to off-target effects. They do not distinguish between neurons involved in seizures and intermingled ‘bystander’ neurons. By analogy, deep brain stimulation (DBS) is an example of a therapy (e.g., for Parkinson Disease, OCD and depression) targeted to specific brain sites, but it is not cell-type specific and can produce side effects. Furthermore, although optogenetics and chemogenetics can be used on demand, the decision when to activate the therapy by light or drug delivery requires an additional step, such as human intervention or a computer that detects seizures. A gene therapy that avoids some of these limitations is the use of eGluCl, which opens in response to accumulation of extracellular glutamate, as occurs in epilepsy, but the effectiveness of this approach in common forms of epilepsy is unknown, and it relies on permanent expression of a non-mammalian membrane protein, which may represent a risk of immunogenicity.
Thus, there is an urgent need to develop alternative therapies for refractory epilepsy, amongst other neurological disorders, with fewer off-target effects or side effects.
The inventors have found that by using a neuronal activity-dependent promoter to drive or alter expression of genes that affect neuronal properties, they can achieve selective modulation of neurons driving seizures or contributing to propagation of seizures in the brain. In this way, neurological disorders, such as refractory epilepsy, can be treated with fewer off-target effects or side effects.
For instance, in one case, when the potassium channel gene KCNA1 is put under the control of the activity-dependent c-Fos promoter, up-regulation of KCNA1 expression is induced in response to intense neuronal activity (e.g. a seizure), and this leads to a decrease in neuronal excitability and neurotransmitter release, resulting in a decrease in susceptibility to seizure initiation or propagation. If the circuit activity returns to near-normal levels, promoter activity decreases, and expression of the potassium channel returns to baseline. This gene therapy is thus specific both for neurons that are over-active (as opposed to bystander neurons) and for the duration that the hyperactivity persists.
In another case, when a fusion protein, composed of dCas9 (also known as endonuclease deficient cas9) and transcriptional activators, is put under the control of the activity-dependent c-Fos promoter, up-regulation of this protein is induced in response to intense neuronal activity (e.g. a seizure), and, in the presence of an appropriate single guide RNA (sgRNA), this can lead to altered expression of an endogenous gene. Altered expression of the endogenous gene (for example, KCNA1) then leads to a decrease in neuronal excitability and neurotransmitter release, resulting in a decrease in susceptibility to seizure initiation or propagation. If the circuit activity returns to near-normal levels, promoter activity decreases, and expression of the fusion protein (and the endogenous gene) returns to baseline. This gene therapy is thus, again, specific both for neurons that are over-active (as opposed to bystander neurons) and for the duration that the hyperactivity persists.
The activity of the c-Fos promoter has been shown to increase in response to several forms of intense neuronal activation (e.g. Hunt et al., 1987 PMID: 3112583; Singewald et al., 2003 PMID: 12586446), and c-Fos activation has also been reported in astrocytes (Morishita et al., PMID: 21785243), oligodendrocytes (Muir & Compston, 1996 PMID: 8926624) and microglia (Eun et al., 2004 PMID: 15522236). Thus, it could not have been predicted that use of an activity-dependent promoter in the treatment of epilepsy would lead to fewer off-target effects. Further, it could not be predicted that activity-dependent promoters used in this way would provide sufficient expression to have a functional effect, or improved functional effect, in vivo.
Accordingly, in one aspect the invention provides an expression vector or vector system for use in a method of treatment of a neurological disorder associated with neuronal hyperexcitability in a subject, the vector or vector system being as defined in the claims. Where relevant, the term “vector” may refer to “vector system” in the detailed description,
In another aspect, the invention provides an expression vector or expression vector system as defined in the claims.
In another aspect, the invention provides an in vitro method of making viral particles as defined in the claims. In another aspect, the invention provides a viral particle as defined in the claims, and such viral particles for use in methods as defined in the claims.
In another aspect, the invention provides a kit as defined in the claims.
In another aspect the invention provides a method of treatment of a neurological disorder, as defined in the claims. In another aspect, the invention provides a method of confirming the presence of a gene product, the method being as defined in the claims.
In another aspect, the invention provides a cell as defined in the claims.
Some particular aspects of the invention will now be discussed in more detail.
The term “neuronal activity-dependent promoter” (or “activity-dependent promoter” as used interchangeably herein) refers to a promoter that alters or drives expression of a target gene in response to changes in neuronal activity in neural cells. Such changes in neuronal activity may result from a neural cell that becomes hyperexcited, for example during a seizure.
The neural cell may be a neuron or a glial cell. In particularly preferred embodiments, the neural cell is a neuron. In some embodiments, the neuron is a cortical neuron.
In some preferred embodiments, the neuronal activity-dependent promoter is an immediate early gene (IEG) promoter. As used herein, the term “immediate early gene” (IEG) is a gene whose expression is increased immediately following a stimulus to a cell comprising the IEG. For example, genes expressed by neurons that exhibit a rapid increase in expression immediately following neuronal stimulation are neuronal lEGs. Such neuronal lEGs have been found to encode a wide variety of polypeptides including transcription factors, cytoskeletal polypeptides, growth factors, and metabolic enzymes as well as polypeptides involved in signal transduction. The identification of neuronal lEGs and the polypeptides they encode provides important information about the function of neurons in, for example, learning, memory, synaptic transmission, tolerance, and neuronal plasticity.
A number of suitable IEG promoters can be used in accordance with the invention. In some preferred embodiments, the IEG promoter comprises c-Fos (or “cFos”). c-Fos is a nuclear proto-oncogene which has been implicated in a number of important cellular events, including cell proliferation (Holt et al. (1986) Proc. Natl. Acad. Set USA 831:4794-4798; Riabowol et al. (1988) J. Cell. Biol. 8: 1670-1676), differentiation (Distel et al. (1987) Cell 49: 835-844; Lord et al. (1993) Mol Cell. Biol. 13:841-851), and tumorigenesis (Cantor et al. (1993) Proc. Natl. Acad. Sci. USA90:10932-10936; Miller et al. (1984) Cell 36:51-60; Ruther et al. (1989) Oncogene 4:861-865.
c-Fos encodes a 62 kDa protein which forms heterodimers with c-Jun, forming an AP-1 transcription factor which binds to DNA at an AP-1 element and stimulates transcription. Fos gene products can also repress gene expression. Sassone et al. (1988) Nature 334:314-319 showed c-Fos inhibits its own promoter, and Gius et al. (1990) and Hay et al. (1989) showed c-Fos inhibits early response genes Egr-1 and c-myc. AP-1 factors have also been shown to inhibit expression of the MHC class l and PEPCK genes (see Gurney et al.(1992) J Biol. Chem. 267: 18133-18139).
c-Fos regulatory region activation can occur in multiple cell types. Where the target cell is a neuron, a stimulus sufficient for c-Fos regulatory region activation may include but is not limited to e.g., neuronal activation, including synaptic activation, electrophysiological activation and the like.
In some embodiments, the c-Fos promoter has a nucleotide sequence comprising or consisting of the nucleotide sequence of SEQ ID NO: 3. In some embodiments, the c-Fos promoter has a nucleotide sequence comprising or consisting of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 3.
In some cases, the c-Fos promoter comprises CREB, SRE, AP1 and SIF motifs. In some cases, the c-Fos promoter consists of CREB, SRE, AP1 and SIF motifs.
CREB-TF (CREB, cAMP response element-binding protein) is a cellular transcription factor. It binds to certain DNA sequences called cAMP response elements (CRE), thereby increasing or decreasing the transcription of the genes. Serum response factor, also known as SRF, is a transcription factor protein. This protein binds to the serum response element (SRE) in the promoter region of target genes. This protein regulates the activity of many immediate early genes, for example c-fos, and thereby participates in cell cycle regulation, apoptosis, cell growth, and cell differentiation. Activator protein 1 (AP1) is a transcription factor that regulates gene expression in response to a variety of stimuli, including cytokines, growth factors, stress, and bacterial and viral infections. Sis-inducible factor (SIF) binding element confers sis/PDGF inducibility to the c-fos promoter.
In other embodiments, the activity-dependent promoter is Egr1 (also known as Zif268), Arc, Homer1a, Bdnf, Creb, Srf, Mef2, Fosb, and Npas4 or synthetic activity-dependent promoters such as PRAM (Sørensen et al., eLife 2016) and ESARE (Kawashima et al., Nature Methods 2013 PMID: 23852453), or part of them or combinations of the above, can be used instead of c-Fos.
In some embodiments, the Egr1 promoter has a nucleotide sequence comprising or consisting of the nucleotide sequence of SEQ ID NO: 18. In some embodiments, the Egr1 promoter has a nucleotide sequence comprising or consisting of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 18.
In some embodiments, the activity-dependent promoter is Arc or an Arc minimal sequence (mArc). Arc is an activity-regulated cytoskeleton-associated protein mostly expressed in glutamatergic neurons in hippocampus and neocortex, with little or no expression in glial cells. In some embodiments, the Arc or mArc promoter has a nucleotide sequence comprising or consisting of the nucleotide sequence of SEQ ID NO: 15. In some embodiments, the mArc promoter has a nucleotide sequence comprising or consisting of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 15. mArc promoter is a truncated version of the full-length Arc promoter.
In other embodiments, the activity-dependent promoter is PRAM (Promoter Robust Activity Marker) or parts of this synthetic promoter: NRAM (NPAS4 Robust Activity Marker) or FRAM (Fos Robust Activity Marker). PRAM consists of repeats of core NRE/AP-1 DNA motifs inserted into the central midline element (CME) to form a secondary structure favoured by transcriptional activation. They have a longer activation window, potentially able to drive more stable and less transient expression of the operatively linked gene. NRAM comprises the NPAS-4 Responsive Element (the consensus binding motif for NPAS4), with a minimal human c-fos promoter. FRAM consists of AP-1 modules (a consensus binding sequence for FOS/JUN family transcription factors) with a human c-fos minimal promoter (see e.g. Sun et al; Cell Volume 181, Issue 2, 16 Apr. 2020, Pages 410-423.e17). In some embodiments, the PRAM, FRAM and NRAM promoters comprise a nucleotide sequence comprising or consisting of the nucleotide sequence of SEQ ID NO: 17. In some embodiments, the promoter has a nucleotide sequence comprising or consisting of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 17.
In other embodiments, the activity-dependent promoter is E-SARE (Enhanced Synaptic Activity Responsive elements). This synthetic promoter contains five repeats of SARE motifs for CREB, MEF2 and SRF binding for transcription initiation, and a minimal Arc promoter (mArc). SARE is part of the Arc promoter. SARE motifs regulate the induction of the immediate-early gene Arc. Mef2 is a critical regulator in heart development and cardiac gene expression. In some embodiments, the E-SARE promoter has a nucleotide sequence comprising or consisting of the nucleotide sequence of SEQ ID NO: 16. In some embodiments, the E-SARE promoter has a nucleotide sequence comprising or consisting of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 16.
NRAM and E-SARE are both composed of sequences from natural promoters. NRAM comprises part of the Npas4 promoter. E-SARE is based on tandem repeats of sequences from the Arc promoter.
In some embodiments, the activity-dependent promoter suppresses the level of expression of a gene, for instance by driving transcription of a short hairpin RNA (shRNA), or another type of RNA that binds to the messenger RNA of an endogenous sodium channel, or other protein.
In some preferred embodiments, the gene that is operably linked to the activity-dependent promoter defined in the claims is KCNA1. KCNA1 (Gene ID 3736, also known as the Potassium Voltage-Gated Channel Subfamily A Member 1, KV1.1, HBK1 and RBK1) is a human gene that encodes the human Kv1.1 potassium channel subunit (also known as Potassium voltage-gated channel subfamily A member 1). By “wild-type KCNA1 gene” it is meant the nucleic acid molecule that is found in human cells and encodes the human Kv1.1 potassium channel subunit. The KCNA1 gene may include regulatory sequences upstream or downstream of the coding sequence. A nucleotide sequence for the wild-type KCNA1 gene, including the non-coding 5′ and 3′ untranslated regions (5′ and 3′ UTRs) is provided in NCBI Reference Sequence NM_000217.2. The coding sequence for the wild-type KCNA1 gene has the nucleotide sequence of SEQ ID NO: 4, which corresponds to positions 1106 to 2593 of NCBI Reference Sequence NM_000217.2.
In some preferred embodiments, the gene product encoded by the gene defined in the claims is the Kv1.1 potassium channel subunit. Kv1 family channels are made up of four subunits. Although four Kv1.1 subunits on their own can make up a functional channel, Kv1.1-containing potassium channels that occur in the mammalian nervous system typically also contain other subunits from the Kv1 family, and so a complete tetrameric channel may contain Kv1.1 together with Kv1.2 or Kv1.4 in various stoichiometries. The term ‘Kv1.1 channel’ is used interchangeably either to indicate a Kv1.1 channel subunit or to indicate a homotetrameric or heterotetrameric channel that contains at least one Kv1.1 subunit.
The Kv1.1 potassium channel is a voltage-gated delayed-rectifier potassium channel that is phylogenetically related to the Drosophila Shaker channel. The amino acid sequence for the wild-type Kv1.1 potassium channel subunit has the amino acid sequence of SEQ ID NO: 5 which is identical to the NCBI Reference Sequence NP_000208.2. Voltage-dependent potassium channels modulate excitability by opening and closing a potassium-selective pore in response to voltage. In many cases, potassium ion flow can be interrupted when an intracellular particle occludes the pore, a process known as fast inactivation. Kv1 potassium channel subunits have six putative transmembrane segments, and the loop between the fifth and sixth segment of each of the four Kv1 subunits that make up a complete channel forms the pore.
During normal production in cells, some of the KCNA1 RNA in the cell is edited by an adenosine deaminase acting on RNA (ADAR) that causes an isoleucine/valine (I/V) recoding event at a single position I400 that lies within the sixth transmembrane domain and lines the inner vestibule of the ion-conducting pore (Hoopengardner et al., Science 301(5634):832-6, 2003). At negative membrane potentials, channels containing unedited 1400 recover from inactivation at a rate around twenty times slower than their edited (V400) counterparts (Bhalla et al., 2004).
In some preferred embodiments, the present invention involves activity-dependent expression of a gene product that is an edited Kv1.1 potassium channel. An “edited Kv1.1 potassium channel” is a functional Kv1.1 potassium channel but contains the isoleucine/valine mutation described above. It is believed that these edited Kv1.1 potassium channels are much quicker at recovering from inactivation than their unedited counterparts.
In some embodiments, an edited Kv1.1 potassium channel has an amino acid sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the amino acid sequence shown in SEQ ID NO: 2 provided it also contains a valine amino acid residue at a position corresponding to amino acid residue 400 shown in SEQ ID NO: 2(the ‘edited position’). In some preferred embodiments, the edited Kv1.1 potassium channel has an amino acid sequence comprising or consisting of the amino acid sequence shown in SEQ ID NO: 2.
An edited Kv1.1 potassium channel that contains a valine amino acid residue at a position corresponding to amino acid residue 400 shown in SEQ ID NO: 2 can be identified by methods known in the art. For example, the edited position can be identified by a sequence alignment between the amino acid sequence of SEQ ID NO: 2 and the amino acid sequence of the edited Kv1.1 potassium channel of interest. Such sequence alignments can then be used to identify the edited position in the edited Kv1.1 potassium channel of interest which, at least in the alignment, is near, or at the same position as, the edited position at amino acid residue 400 in the amino acid sequence shown in SEQ ID NO: 2.
A functional Kv1.1 potassium channel is a protein that retains the normal activity of a potassium channel, e.g. the channels are able to open and close in response to voltage. Methods of testing that the Kv1.1 potassium channels are functional are known in the art and some of which are described herein. Briefly, a suitable method for confirming that the Kv1.1 potassium channel is functional involves transfecting cells with an expression vector encoding a Kv1.1 potassium channel and using electrophysiological techniques such as patch clamping to record currents of the potassium channels.
The wild-type Kv1.1 potassium channel comprises a tyrosine amino acid at position 379 as shown in SEQ ID NO: 5. In some embodiments, an edited Kv1.1 potassium channel comprises a tyrosine amino acid residue at a position corresponding to amino acid residue 379 shown in SEQ ID NO: 2.
In other embodiments, an edited Kv1.1 potassium channel comprises a valine amino acid residue at a position corresponding to amino acid residue 379 shown in SEQ ID NO: 2. An example of an edited Kv1.1 potassium channel with this amino acid sequence is shown in SEQ ID NO: 12. Without wishing to be bound by any particular theory, it is believed that a Y379V mutation reduces the sensitivity of Kv1.1 channels to tetraethyl ammonium (TEA) without altering the functional properties of the potassium channel. For example, this change in sensitivity allows transgenic Kv1.1 channels to be pharmacologically isolated from their wild-type counterparts in patch clamp electrophysiology experiments (Heeroma et al. 2009).
In some embodiments, an “engineered KCNA1 gene” is used. An engineered KCNA1 gene differs from the nucleotide sequence of the wild-type KCNA1 gene as described herein but still encodes for a functional Kv1.1 potassium channel. As used herein, an engineered KCNA1 gene has a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the nucleotide sequence shown in SEQ ID NO: 1. In some preferred embodiments, the engineered KCNA1 gene has a nucleotide sequence comprising or consisting of the nucleotide sequence shown in SEQ ID NO: 7.
As described above, an embodiment of the invention includes an engineered KCNA1 gene encoding an edited potassium channel that comprises a valine amino acid residue at position 379, as shown in SEQ ID NO: 12. An example of an engineered KCNA1 gene that encodes the amino acid sequence shown in SEQ ID NO: 12 is the nucleotide sequence shown in SEQ ID NO: 11. In some embodiments, the engineered KCNA1 gene has a nucleotide sequence comprising or consisting of the nucleotide sequence shown in SEQ ID NO: 11, or has at least 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the nucleotide sequence shown in SEQ ID NO: 11.
In other embodiments, the gene product is another protein that affects neuronal excitability or neurotransmitter release, including other potassium channels such as Kv1.2, or neurotransmitter receptors such as GABAa or GABAb receptors, adenosine A1 receptors, and NPY Y2 or Y5 receptors, or neuropeptides such as galanin, NPY or dynorphin.
In some preferred embodiments, the gene that is operably linked to the activity-dependent promoter is defined in the claims as KCNJ2. KCNJ2 encodes the inward-rectifying potassium chancel Kir2.1, which is normally expressed in skeletal muscle. Kir2.1 contributes to maintaining a negative resting membrane potential, thus reducing intrinsic excitability.
In some preferred embodiments, the gene product encoded by the gene defined in the claims is the inward-rectifying potassium channel Kir2.1, which is described above. The nucleotide sequence of KCNJ2 is provided herein.
In some embodiments, the KCNJ2 gene has a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the nucleotide sequence shown in SEQ ID NO: 13. In some embodiments, the Kir2.1 gene has an amino acid sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the amino acid sequence shown in SEQ ID NO: 14.
In another embodiment, the present invention involves activity-dependent expression of an intermediate gene product that indirectly affects neuronal excitability by altering (increasing or decreasing) the expression of a further gene or gene product, which may be an endogenous gene or gene product. The further/endogenous gene or gene product may be any gene or gene product described herein, such as KCNA1 or KCNJ2. Other further/endogenous genes or gene products include neurotransmitter receptors such as GABAa or GABAb receptors, adenosine A1 receptors, and NPY Y2 or Y5 receptors, or neuropeptides such as galanin, NPY or dynorphin.
Altering expression of the further gene or gene product by activity-dependent expression of the intermediate gene product can, in some cases, be achieved through activity-dependent expression of a fusion protein composed of dCas9 (also known as endonuclease deficient Cas9) and transcriptional activators. The fusion protein may also be composed of any suitable dcas protein, such spCas9 or saCas9. In the presence of an appropriate single guide RNA (sgRNA) this strategy, also known as CRISPR activation (CRISPRa) can lead to increased transcription of a further gene such as KCNA1 that reduces neuronal excitability. In some cases, the sgRNA targets a target sequence with 100% efficiency. The sgRNA may be constitutively expressed and operably linked to a separate promoter, such as RNA polymerase III (e.g. U6). The separate promoter may also be any promoter suitable to express sgRNA, such as an RNA polymerase, for example RNA polymerase II. The sgRNA and separate promoter may also be comprised by, or separate to, the expression vectors and vector systems disclosed herein. In some cases, the sgRNA may also be operably linked to the activity-dependent promoter, or to an intermediate inducible promoter such as Tet-On.
In some embodiments, the sgRNA comprises or consists of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to the nucleotide sequence shown in SEQ ID NO: 37.
Activity-dependent expression of an intermediate gene product to indirectly affect neuronal excitability may be achieved via an intermediate expression system, such as an intermediate inducible expression system. Such intermediate expression systems are, in a general sense, known in the art, and may be appropriately selected by the skilled person in order to optimise expression of the intermediate gene or further gene.
For example, the intermediate expression system may be an inducible expression system such as Tet-On. See e.g. Gaia Colasante et. al (Brain, Volume 143, Issue 3, March 2020, Pages 891-905, https://do|org/10.1093/brain/awaa045), the contents of which is incorporated herein by reference in its entirety. An exemplary embodiment of this aspect of the invention is shown in
Of the currently available inducible gene expression systems, Tet-On is the most widely characterised. In some embodiments, in order to improve brain penetration and reduce side-effects in human subjects, the intermediate inducible gene expression system may be a “GeneSwitch™” system. “GeneSwitch™”, uses a chimeric protein, consisting of a truncated human progesterone receptor that does not respond to endogenous steroids, along with a Gal4 DNA binding domain and a P65 activation domain. The receptor is activated by mifepristone, which frees the complex from co-repressors and allows it to initiate transcription of the desired gene in the nucleus by binding to an upstream activating sequence (UAS).
The intermediate expression system can also comprise expression of a modified ecdysone receptor that regulates an optimized ecdysone responsive promoter. The intermediate expression systems can also be based on cumate-induced binding of the cumate repressor to the cumate operator, rapamycin-induced interaction between FKBP12 and FRAP, FKCsA-induced interaction between FKBP and cyclophilin, ABA induced interaction between PYL1 and ABI1, and the “riboswitch” system. (Kallunki et al PMC6721553).
Constitutive CRISPRa to upregulate mouse Kcna1 expression has been reported to have an anti-epileptic effect (Colasante et al., 2020). However, it could not have been predicted that placing CRISPRa under the control of an activity-dependent promoter such as c-Fos, would lead to activity-dependent anti-epileptic activity with the advantageous properties disclosed herein, for example temporal reversibility and spatial specificity for neurons involved in seizures. The nucleotide sequences of dCas9 and the transcriptional activator VP64 are provided herein, as is the sequence of an sgRNA that recognises a promoter sequence of the mouse Kcna1 gene.
Alignment and calculation of percentage amino acid or nucleotide sequence identity can be achieved in various ways known to a person of skill in the art, for example, using publicly available computer software such as ClustalW 1.82, T-coffee or Megalign (DNASTAR) software. When using such software, the default parameters, e.g. for gap penalty and extension penalty, are preferably used. The default parameters of ClustalW 1.82 are: Protein Gap Open Penalty = 10.0, Protein Gap Extension Penalty = 0.2, Protein matrix = Gonnet, Protein/DNA ENDGAP = -1, Protein/DNA GAPDIST = 4.
The percentage identity can then be calculated from the multiple alignment as (N/T)*100, where N is the number of positions at which the two sequences share an identical residue, and T is the total number of positions compared. Alternatively, percentage identity can be calculated as (N/S)*100 where S is the length of the shorter sequence being compared. The amino acid/polypeptide/nucleic acid sequences may be synthesised de novo, or may be native amino acid/polypeptide/nucleic acid sequence, or a derivative thereof.
Due to the degeneracy of the genetic code, it is clear that any nucleic acid sequence could be varied or changed without substantially affecting the sequence of the protein encoded thereby, to provide a functional variant thereof. Suitable nucleotide variants are those having a sequence altered by the substitution of different codons that encode the same amino acid within the sequence, thus producing a silent change. Other suitable variants are those having homologous nucleotide sequences but comprising all, or portions of, sequence which are altered by the substitution of different codons that encode an amino acid with a side chain of similar biophysical properties to the amino acid it substitutes, to produce a conservative change. For example small non-polar, hydrophobic amino acids include glycine, alanine, leucine, isoleucine, valine, proline, and methionine. Large non-polar, hydrophobic amino acids include phenylalanine, tryptophan and tyrosine. The polar neutral amino acids include serine, threonine, cysteine, asparagine and glutamine. The positively charged (basic) amino acids include lysine, arginine and histidine. The negatively charged (acidic) amino acids include aspartic acid and glutamic acid.
In some embodiments, the level of expression of the gene product increases when the neuron becomes more excited and decreases when the neuron becomes less excited.
One aspect of the invention provides expression vectors for use, as defined in the claims, in a method of treatment of a neurological disorder associated with neuronal hyperexcitability in a subject. Said methods of treatment may be prophylactic.
In certain aspects, the invention also provides the use of expression vectors and viral particles as described herein for the manufacture of a medicament for the treatment of said neurological disorder of a human or animal subject, expression vectors as described herein for use in the treatment of a said neurological disorder of a human or animal subject, and methods of treatment of said neurological disorder which comprises administering the expression vectors and viral particles as described herein to an individual in need thereof. The animal subject may be a mouse or a rat.
In some embodiments, the method of treatment is self-limiting after seizures end (“close loop” or “closed loop” therapy).
The neurological disorders as described herein are associated with neuronal hyperexcitability. As used herein, “hyperexcitability” is a characteristic feature of epilepsy in which the likelihood that neural networks become hypersynchronized, with excessive neuronal firing, is increased. The underlying mechanisms are incompletely understood and may include loss of inhibitory neurons, such as GABAergic interneurons, that would normally balance out the excitability of other neurons, or changes in the intrinsic properties of excitatory neurons that make them more likely to fire abnormally. Among other possible mechanisms are that the levels of GABA and the sensitivity of GABAA receptors to the neurotransmitter may decrease, resulting in less inhibition.
Non-limiting examples of neurological disorders associated with neuronal hyperexcitability include seizure disorders (such as epilepsy), Alzheimer’s disease, multiple sclerosis, Parkinson’s disease, tremor and other movement disorders, chronic pain, migraine, major depression, bipolar disorder, anxiety, and schizophrenia. In particularly preferred embodiments, the treatment is for epilepsy, for example idiopathic, symptomatic, and cryptogenic epilepsy. In particularly preferred embodiments, the epilepsy is neocortical epilepsy, temporal lobe epilepsy, especially if it is resistant to drugs used at therapeutic concentrations (pharmacoresistant or refractory epilepsy).
In some cases, seizures are accompanied by a profound depolarization and bursts of firing of pyramidal neurons in the cortex at frequencies greater than 50 Hz, which rarely if ever occur in physiological circumstances. Although activity-dependent promoters have been used to tag neurons that have been recruited by very strong sensory or other stimuli (peripheral nociceptor stimulation, fear-inducing electric shocks, cocaine), recordings from neurons imply that seizures induce much higher levels of activity than such stimuli. Furthermore, the CNS regions where such sensory stimuli have been shown to induce activity-dependent promoter function are different from those typically involved in seizures.
In some preferred embodiments, the neurological disorder is a disorder characterized by episodes of abnormal cellular activity, such as migraine, cluster headache, trigeminal neuralgia, post-herpetic neuralgia, paroxysmal movement disorders, uni- or bipolar affective disorders, anxiety and phobias. In some such disorders (migraine in particular), the abnormal activity may result in neuronal depolarization and electrical silence known as cortical spreading depolarization or cortical spreading depression, and this phenomenon has been implicated in sudden unexpected death in epilepsy (SUDEP).
The treatments described herein may be used to quench or block epileptic activity. The treatments may be used to reduce the frequency of seizures. The treatments may be used to temporally (for example, over 2, 6, 24, 48 or 72 hours) or permanently reduce abnormal neuronal excitability.
In some embodiments, the vector does not affect spontaneous locomotion or memory in a subject, optionally wherein spontaneous locomotion or memory is measured using an open field test, object localisation test, or T maze test.
In some embodiments, the expression vectors are only locally active in the seizure focus of the brain of a subject. In some cases, the expression vectors are only locally active in neurons capable of driving a seizure and/ generating sustained firing. In some cases, the expression vectors are only locally active in over-depolarised neurons.
In some embodiments, the vector or vector system can cause a reduction in the spike frequency of a neuron of the subject by more than 5%, or by more than 10%, or by more than 20%, or by more than 30%, or by more than 40%, or by more than 50%, or by more than 60%, or by more than 70%, or by more than 80%, or by more than 90%, or by more than 91%, or by more than 92%, or by more than 93%, or by more than 94%, or by more than 95%, or by more than 96%, or by more than 97%, or by more than 98%, or by more than 99%, or by 100%.
In some embodiments, the vector or vector system can cause a reduction in the spike frequency of a neuron of the subject by more than 75%. The reduction in the spike frequency of the neuron can be measured using multi-electrode arrays on or after 21 DIV (days in vitro). The reduction in the spike frequency may also be measured using calcium imaging or extracellular field potential recordings on or after 21 DIV. The reduction in the spike frequency of the neuron is measured relative to a vector comprising SEQ ID NO: 6. In some cases, the neuron is a primary cortical neuron.
In some embodiments, the vector or vector system can cause fewer than 10 action potentials per second, or fewer than 5 action potentials per second, or fewer than 4 action potentials per second, or fewer than 3 action potentials per second, or fewer than 2 action potentials per second, or no action potentials per second, in a neuron. In some embodiments, the vector or vector system can cause a greater than 50%, greater that 55%, greater that 60%, greater that 65%, greater that 70%, greater that 75%, greater that 80%, greater that 85%, greater that 90%, greater that 95%, or 100% reduction in action potentials per second. The number of action potentials may be measured using ex vivo acute hippocampal slice electrophysiology.
In some embodiments, the vector or vector system can cause a resting membrane potential in a neuron of less than -50 mV, or less than -60 mV, or less than -70 mV, or less than -80 mV, or less than -90 mV, or less than -100 mV. In some embodiments, the vector or vector system can increase the threshold for action potentials in a neuron to more than 50 pA, or more than 75 pA, or more than 100 pA, or more than 150 pA, or more than 200 pA, or more than 250 pA, or more than 300 pA, or more than 350 pA, or more than 400 pA, or more than 450 pA, or more than 500 pA, or more than 550 pA, or more than 600 pA, or more than 700 pA, or more than 800 pA, or more than 900 pA, or more than 1000 pA, wherein the threshold is the sum of current threshold and holding cu rre nt.
In some embodiments, the vector or vector system can cause less than 5 spikes/second in a primary neuronal culture grown on multi-electrode arrays (MEAs), as described in the examples. Spike is defined as aggregate neuronal activity. In some embodiments, the vector or vector system can cause less than 10, or less than 5 bursts /minute in a primary neuronal culture grown on MEAs, as described in the examples. In some embodiments, the vector or vector system can cause burst durations of less than 200 msec in a primary neuronal culture grown on MEAs, as described in the examples. In some embodiments, the vector or vector system can cause a mean number of spikes per burst of less than 20, or less than 15 in a primary neuronal culture grown on MEAs, as described in the examples.
In some embodiments, the number of action potentials, resting membrane potential, or threshold for action potentials is measured in an acute hippocampal slice from a subject. In some embodiments, the number of action potentials, resting membrane potential, or threshold for action potentials is measured using acute hippocampal slice electrophysiology and/or patch clamp electrophysiology.
In some embodiments, the vector or vector system can cause a greater anti-epileptic effect in a neuron driving a second seizure in a subject, than the anti-epileptic effect in the neuron driving the first seizure in the subject. In some embodiments, the anti-epileptic effect is measured using any of the appropriate methods described herein.
In some cases, the vector or vector system can prevent a second seizure in a subject, wherein the second seizure is subsequent to a first seizure in the subject.
The viral particles and expression vectors described herein can be delivered to the subject in a variety of ways, such as direct injection of the viral particles into the brain. For example, the treatment may involve direct injection of the viral particles into the cerebral cortex, in particular the neocortex or hippocampal formation. Another site of injection is an area of cortical malformation or hamartoma suspected of generating seizures, as occurs in focal cortical dysplasia or tuberous sclerosis. The treatment may involve direct injection of the viral particles into the location in the brain where it is believed to be functionally associated with the disorder. For example, where the treatment is for myoclonic epilepsy this may involve direct injection of the viral particles into the motor cortex; where the treatment is for chronic or episodic pain, this may involve direct injection of the viral particles into the dorsal root ganglia, trigeminal ganglia or sphenopalatine ganglia; and where the treatment is for Parkinson’s disease, this may involve direct injection of the viral particles into the substantia nigra, subthalamic nucleus, globus pallidus or putamen. The particular method and site of administration would be at the discretion of the physician who would also select administration techniques using his/her common general knowledge and those techniques known to a skilled practitioner.
The invention may also be used to treat multiple epileptic foci simultaneously by injection directly into the multiple identified loci.
The patient may be one who has been diagnosed as having drug-resistant or medically-refractory epilepsy, by which is meant that epileptic seizures continue despite adequate administration of antiepileptic drugs.
The subject may be one who has been diagnosed as having well defined focal epilepsy affecting a single area of the neocortex of the brain. Focal epilepsy can arise, for example, from developmental abnormalities or following strokes, tumours, penetrating brain injuries or infections.
Following administration of the viral particles, the recipient individual may exhibit reduction in symptoms of the disease or disorder being treated. For example, for an individual being treated who has a seizure disorder such as epilepsy, the recipient individual may exhibit a reduction in the frequency or severity of seizures. This may have a beneficial effect on the disease condition in the individual.
The term “treatment,” as used herein in the context of treating a condition, pertains generally to treatment and therapy of a human, in which some desired therapeutic effect is achieved, for example, the inhibition of the progress of the condition, and includes a reduction in the rate of progress, a halt in the rate of progress, regression of the condition, amelioration of the condition, and cure of the condition. Treatment as a prophylactic measure (i.e., prophylaxis, prevention) is also included.
The viral particle can be delivered in a therapeutically-effective amount.
The term “therapeutically-effective amount” as used herein, pertains to that amount of the viral particle which is effective for producing some desired therapeutic effect, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired treatment regimen.
Similarly, the term “prophylactically effective amount,” as used herein pertains to that amount of the viral particle which is effective for producing some desired prophylactic effect, commensurate with a reasonable benefit/risk ratio, when administered in accordance with a desired treatment regimen.
“Prophylaxis” in the context of the present specification should not be understood to describe complete success i.e. complete protection or complete prevention. Rather prophylaxis in the present context refers to a measure which is administered in advance of detection of a symptomatic condition with the aim of preserving health by helping to delay, mitigate or avoid that particular condition.
While it is possible for the viral particle to be used (e.g., administered) alone, it is often preferable to present it as a composition or formulation e.g. with a pharmaceutically acceptable carrier or diluent.
The term “pharmaceutically acceptable,” as used herein, pertains to compounds, ingredients, materials, compositions, dosage forms, etc., which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of the subject in question (e.g., human) without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio. Each carrier, diluent, excipient, etc. must also be “acceptable” in the sense of being compatible with the other ingredients of the formulation.
In some embodiments, the composition is a pharmaceutical composition (e.g., formulation, preparation, medicament) comprising, or consisting essentially of, or consisting of as a sole active ingredient, viral particle as described herein, and a pharmaceutically acceptable carrier, diluent, or excipient.
As described in WO2008096268, in gene therapy embodiments employing delivery of the viral particle, the unit dose may be calculated in terms of the dose of viral particles being administered. Viral doses include a particular number of virus particles or plaque forming units (pfu). For embodiments involving adenovirus, particular unit doses include 103, 104, 106, 106, 107, 108, 109, 1010, 1011, 1012, 1013 or 1014 pfu. Particle doses may be somewhat higher (10 to 100 fold) due to the presence of infection-defective particles.
In some embodiments the methods or treatments of the present invention may be combined with other therapies, whether symptomatic or disease modifying.
The term “treatment” includes combination treatments and therapies, in which two or more treatments or therapies are combined, for example, sequentially or simultaneously.
For example it may be beneficial to combine treatment with a compound as described herein with one or more other (e.g., 1, 2, 3, 4) agents or therapies.
Appropriate examples of co-therapeutics will be known to those skilled in the art on the basis of the disclosure herein. Typically the co-therapeutic may be any known in the art which it is believed may give therapeutic effect in treating the diseases described herein, subject to the diagnosis of the individual being treated. For example epilepsy can sometimes be ameliorated by directly treating the underlying etiology, but anticonvulsant drugs, such as phenytoin, gabapentin, lamotrigine, levetiracetam, carbamazepine, clobazam, topiramate, and others, which suppress the abnormal electrical discharges and seizures, are the mainstay of conventional treatment (Rho & Sankar, 1999, Epilepsia 40: 1471-1483).
The particular combination would be at the discretion of the physician who would also select dosages using his/her common general knowledge and dosing regimens known to a skilled practitioner.
The agents (i.e. viral particle, plus one or more other agents) may be administered simultaneously or sequentially, and may be administered in individually varying dose schedules and via different routes. For example, when administered sequentially, the agents can be administered at closely spaced intervals (e.g., over a period of 5-10 minutes) or at longer intervals (e.g., 1, 2, 3, 4 or more hours apart, or even longer periods apart where required), the precise dosage regimen being commensurate with the properties of the therapeutic agent(s).
An expression vector as used herein is a DNA molecule used to transfer and express foreign genetic material in a cell. Such vectors include a promoter sequence operably linked to the gene encoding the protein to be expressed. “Promoter” means a minimal DNA sequence sufficient to direct transcription of a DNA sequence to which it is operably linked. “Promoter” is also meant to encompass those promoter elements sufficient for promoter-dependent gene expression controllable for cell type specific expression; such elements may be located in the 5′ or 3′ regions of the native gene. Alternatively, an expression vector may be an RNA molecule that undergoes reverse transcription to DNA as a result of the reverse transcriptase enzyme.
An expression vector may also include a termination codon and expression enhancers. Any suitable vectors, enhancers and termination codons may be used to express the gene product, such as an edited Kv1.1 potassium channel, from an expression vector according to the invention. Suitable vectors include plasmids, binary vectors, phages, phagemids, viral vectors and artificial chromosomes (e.g. yeast artificial chromosomes or bacterial artificial chromosomes). As described in more detail below, preferred expression vectors include viral vectors such as AAV vectors.
An expression vector may additionally include a reporter gene encoding a reporter protein. An example of a reporter protein is a green fluorescent protein (“GFP”). A reporter gene may be operably linked to its own promoter or, more preferably, may be operably linked to the same promoter as the gene product as defined in the invention. As an example, the KCNA1 gene and reporter gene may be located either side of a sequence encoding a 2A peptide, such as a T2A peptide. 2A peptides are short (~20 amino acids) sequences that permit multicistronic gene expression from single promoters by impairing peptide bond formation during ribosome-mediated translation (Szymczak and Vignali, 2005). Having the reporter gene operably linked to the same promoter as the gene product, is thought to act as a reliable indicator of gene product expression. An expression vector including a reporter gene may be particularly useful in preclinical applications, for example for use in animal models where it can be used to help assess the localisation of gene expression. The gene encoding GFP may be GFP, dsGFP or dscGFP.
In other embodiments, the expression vector lacks a sequence encoding a reporter protein. This may be preferred for regulatory reasons, for example. In embodiments of the invention, reporting or detecting the gene product of the disclosure may be achieved in different ways - for example based on its engineered sequence. In some embodiments, the expression vector lacks a sequence encoding GFP and/or a sequence encoding a 2A peptide, such as a T2A peptide.
Generally speaking, those skilled in the art are well able to construct vectors and design protocols for recombinant gene expression. Suitable vectors can be chosen or constructed, containing, in addition to the elements of the invention described above, appropriate regulatory sequences, including promoter sequences, terminator fragments, polyadenylation sequences, marker genes and other sequences as appropriate. Molecular biology techniques suitable for the expression of polypeptides in cells are well known in the art. For further details see, for example, Molecular Cloning: a Laboratory Manual: 2nd edition, Sambrook et al, 1989, Cold Spring Harbor Laboratory Press or Current Protocols in Molecular Biology, Second Edition, Ausubel et al. eds., John Wiley & Sons, (1995, and periodic supplements).
The term “operably linked” used herein includes the situation where a selected gene and promoter are covalently linked in such a way as to place the expression of the gene (i.e. polypeptide coding) under the influence or control of the promoter. Thus, a promoter is operably linked to a gene if the promoter is capable of effecting transcription of the gene into RNA in a cell. Where appropriate, the resulting RNA transcript may then be translated into a desired protein or polypeptide. The promoter is suitable to effect expression of the operably linked gene in a mammalian cell. Preferably, the mammalian cell is a human cell.
The disclosed genes, such as an engineered KCNA1 gene, and gene products, such as an edited Kv1.1 potassium channel, can have the requisite features and sequence identity as described herein in relation to the expression vectors.
In some preferred embodiments, the expression vector comprises or consists of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to one of the following sequences:
mArc-dsGFP-KCNA1 (SEQ ID NO: 19); mArc-dsGFP-KCNJ2 (SEQ ID NO: 21); ESARE-dsGFP-KCNA1 (SEQ ID NO: 23); ESARE-dsGFP-KCNJ2 (SEQ ID NO: 25); NRAM-hCfos-dsGFP-KCNA1 (SEQ ID NO: 27); NRAM-hCfos -dsGFP-KCNJ2 (SEQ ID NO: 29); Egr1-dsGFP-KCNA1 (SEQ ID NO: 31); Egr1-dsGFP-KCNJ2 (SEQ ID NO: 33).
In some embodiments, the expression vector is as shown in any one of
A preferred expression vector for use with the present invention is a viral vector, such as a lentiviral or AAV vector. A particularly preferred expression vector is an adeno associated viral vector (AAV vector).
In some instances, the vector is a recombinant AAV vector. AAV vectors are DNA viruses of relatively small size that can integrate, in a stable and site-specific manner, into the genome of the cells that they infect. They are able to infect a wide spectrum of cells without inducing significant effects on cellular growth, morphology or differentiation. The AAV genome has been cloned, sequenced and characterized. It encompasses approximately 4700 bases and contains an inverted terminal repeat (ITR) region of approximately 145 bases at each end, which serves as an origin of replication for the virus. The remainder of the genome is divided into two essential regions that carry the encapsidation functions: the left-hand part of the genome, that contains the rep gene involved in viral replication and expression of the viral genes; and the right-hand part of the genome, that contains the cap gene encoding the capsid proteins of the virus.
AAV vectors may be prepared using standard methods in the art. Adeno-associated viruses of any serotype are suitable (see, e.g., Blacklow, pp. 165-174 of “Parvoviruses and Human Disease” J. R. Pattison, ed. (1988); Rose, Comprehensive Virology 3:1, 1974; P. Tattersall “The Evolution of Parvovirus Taxonomy” in Parvoviruses (J R Kerr, S F Cotmore. M E Bloom, R M Linden, C R Parrish, Eds.) p5-14, Hudder Arnold, London, UK (2006); and D E Bowles, J E Rabinowitz, R J Samulski “The Genus Dependovirus” (J R Kerr, S F Cotmore. M E Bloom, R M Linden, C R Parrish, Eds.) p15-23, Hudder Arnold, London, UK (2006), the disclosures of which are hereby incorporated by reference herein in their entireties). Methods for purifying for vectors may be found in, for example, U.S. Pat. Nos. 6,566,118, 6,989,264, and 6995006 and International Patent Application Publication No.: W0/1999/011764 titled “Methods for Generating High Titer Helper-free Preparation of Recombinant AAV Vectors”, the disclosures of which are herein incorporated by reference in their entirety.
Preparation of hybrid vectors is described in, for example, PCT Application No. PCT/US2005/027091, the disclosure of which is herein incorporated by reference in its entirety. The use of vectors derived from the AAVs for transferring genes in vitro and in vivo has been described (See e.g., International Patent Application Publication Nos: WO 1/18088 and WO 93/09239; U.S. Pat. Nos. 4,797,368, 6,596,535, and 5,139,941; and European Patent No: 0488528, all of which are herein incorporated by reference in their entirety). These publications describe various AAV-derived constructs in which the rep and/or cap genes are deleted and replaced by a gene of interest, and the use of these constructs for transferring the gene of interest in vitro (into cultured cells) or in viva (directly into an organism). The replication defective recombinant AAVs according to the invention can be prepared by co-transfecting a plasmid containing the nucleic acid sequence of interest flanked by two AAV inverted terminal repeat (ITR) regions, and a plasmid carrying the AAV encapsidation genes (rep and cap genes), into a cell line that is infected with a human helper virus (for example an adenovirus). The AAV recombinants that are produced are then purified by standard techniques.
In some instances, useful AAV vectors for the expression constructs as described herein include those encapsidated into a virus particle (e.g. AAV virus particle including, but not limited to, AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, AAV13, AAV14, AAV15, AAV16 and AAVrh10). Accordingly, the instant disclosure includes a recombinant virus particle (recombinant because it contains a recombinant polynucleotide) comprising any of the vectors described herein.
In some embodiments, the viral vector contains a sequence encoding a reporter protein, such as a fluorescent protein. In other embodiments the viral vector lacks a sequence encoding a reporter protein, such as a fluorescent protein.
In some embodiments, the vector comprises a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identity to the nucleotide sequence of SEQ ID NO: 8, SEQ ID NO: 9, or SEQ ID NO: 10. In some embodiments, the viral vector is the nucleotide sequence of SEQ ID NO: 8, SEQ ID NO: 9, or SEQ ID NO: 10.
In some preferred embodiments, the viral vector comprises or consists of a nucleotide sequence having at least 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% sequence identity to one of the following sequences:
AAV- mArc-dsGFP-KCNA1 (SEQ ID NO: 20); AAV- mArc-dsGFP-KCNJ2 (SEQ ID NO: 22); AAV- ESARE-dsGFP-KCNA1 (SEQ ID NO: 24); AAV- ESARE-dsGFP-KCNJ2 (SEQ ID NO: 26); AAV- NRAM-hCfos -dsGFP-KCNA1 (SEQ ID NO: 28); AAV- NRAM-hCfos -dsGFP-KCNJ2 (SEQ ID NO: 30); AAV- Egr1-dsGFP-KCNA1 (SEQ ID NO: 32); Egr1-dsGFP-KCNJ2 (SEQ ID NO: 34).
In some embodiments, the viral vector additionally comprises genes encoding viral packaging and envelope proteins.
In some embodiments, the viral vector is a lentiviral vector. In some embodiments, the lentiviral vector is a non-integrating lentiviral vector (NILV). Vector particles produced from these vectors do not integrate their viral genome into the genome of the cells and therefore are useful in applications where transient expression is required or for sustained episomal expression such as in quiescent cells. NILVs can be developed by mutations in the integrase enzyme or by altering the 5′ LTR and/or the 3′ LTR to prevent integrase from attaching these sequences. These modifications eliminate integrase activity without affecting reverse transcription and transport of the pre-integration complex to the nucleus. Without wishing to be bound by any particular theory, when a NILV enters a cell the lentiviral DNA is expected to remain as remains in the nucleus as an episome, leading to sustained expression in non-dividing cells (post-mitotic cells) such as neurons.
In some embodiments, the vector further comprises an AmpR gene, and/or a hGh poly(A) signal gene, and/or one or more origin of replication genes.
The invention also includes in vitro methods of making viral particles, such as lentiviral particles or adeno-associated viral particles. In one embodiment, this method involves transducing mammalian cells with a viral vector as described herein and expressing viral packaging and envelope proteins necessary for particle formation in the cells and culturing the transduced cells in a culture medium, such that the cells produce viral particles that are released into the medium. An example of a suitable mammalian cell is a human embryonic kidney (HEK) 293 cell.
It is possible to use a single expression vector that encodes all the viral components required for viral particle formation and function. Most often, however, multiple plasmid expression vectors or individual expression cassettes integrated stably into a host cell are utilised to separate the various genetic components that generate the viral vector particles.
In some embodiments, expression cassettes encoding the one or more viral packaging and envelope proteins have been integrated stably into a mammalian cell. In these embodiments, transducing these cells with a viral vector described herein is sufficient to result in the production of viral particles without the addition of further expression vectors.
In other embodiments, the in vitro methods involve using multiple expression vectors. In some embodiments, the method comprises transducing the mammalian cells with one or more expression vectors encoding the viral packaging and envelope proteins that encode the viral packaging and envelope proteins necessary for particle formation.
Examples of suitable viral packaging and envelope proteins and expression vectors encoding these proteins are commercially available and well known in the art. In general, the viral packaging expression vector or expression cassette expresses the gag, pol, rev, and tat gene regions of HIV-1 which encode proteins required for vector particle formation and vector processing. In general, the viral envelope expression vector or expression cassette expresses an envelope protein such as VSV-G. In some cases, the packaging proteins are provided on two separate vectors - one encoding Rev and one encoding Gag and Pol. Examples of lentiviral vectors along with their associated packaging and envelope vectors include those of Dull, T. et al., “A Third-generation lentivirus vector with a conditional packaging system” J. Virol 72(11):8463-71 (1998), which is herein incorporated by reference.
The ssDNA AAV genome contains two open reading frames, Rep and Cap, flanked by two 145 base inverted terminal repeats (ITRs) fundamental for the synthesis of the complementary DNA strand. Rep and Cap produce multiple proteins (Rep78, Rep68, Rep52, Rep40, which are required for the AAV life cycle; and VP1, VP2, VP3, which are capsid proteins). The transgene will be inserted between the ITRs and Rep and Cap in trans. An AAV2 backbone is commonly used and is described in Srivastava et al., J. Virol., 45: 555-564 (1983). Cis-acting sequences directing viral DNA replication (ori), packaging (pkg) and host cell chromosome integration (int) are contained within the ITRs. AAVs also require a helper plasmid containing genes from adenovirus. These genes (E4, E2a and VA) mediate AAV replication. An example of a pAAV plasmid is available from Addgene (Cambridge, MA, USA) as plasmid number 112865 or 60958.
Following release of viral particles, the culture medium comprising the viral particles may be collected and, optionally the viral particles may be separated from the culture medium. Optionally, the viral particles may be concentrated.
Following production and optional concentration, the viral particles may be stored, for example by freezing at -80° C. ready for use by administering to a cell and/or use in therapy.
The invention also provides viral particles, for example those produced by the methods described herein. As used herein, a viral particle comprises a DNA or RNA genome packaged within the viral envelope that is capable of infecting a cell, e.g. a mammalian cell. A viral particle may be integrase deficient, e.g. it may contain a mutant integrase enzyme or contain alterations in the 5′ and/or 3′ LTRs as described herein.
The invention also provides a cell comprising the nucleic acid or vector described above. In some embodiments, this cell is a mammalian cell such as a human cell. In some embodiments, the cell is a human embryonic kidney cell (HEK) 293. In some embodiments, the cell is derived from a neuroblastoma cell-line.
The invention also provides kits that comprise an expression vector as described herein and one or more viral packaging and envelope expression vectors also described herein. In some embodiments the viral packaging expression vector is an integrase-deficient viral packaging expression vector.
The invention also provides a method of confirming the presence of a gene product as described herein, such as engineered KCNA1, in a cell.
A limitation of clinical translation using certain gene sequences is that it is difficult to detect their expression against the background endogenous channels present in the brain.
The sequences of gene product as described herein may differ from endogenous wild-type gene products found in cells, such that when this gene is transcribed into RNA it incorporates a unique RNA sequence (an ‘RNA-fingerprint’). This RNA-fingerprint permits specific tracking of transgene expression with RNA-targeted techniques that would otherwise fail to distinguish between transgenic and endogenous gene products. This is particularly useful where it is important to determine the localisation of gene expression without having to include sequences encoding fluorescent tags or epitopes that could potentially result in immunogenicity.
For example, tissue removed from patients who have been treated with a gene product could be examined to determine where and in which cell types (excitatory neurons as expected, or inhibitory neurons or glial cells) the gene product was present. Such tissue could be obtained, for instance, from epilepsy surgery in the event of epilepsy gene therapy failure, or post-mortem. This data is expected to be useful for preclinical dosage calculation, biodistribution studies, regulatory approval and further clinical development on gene therapy.
Thus, in one embodiment the method comprises transducing a cell with an expression vector as described herein or administering a viral particle as described herein to a cell under conditions that permit expression of a gene product of interest and detecting the presence of the gene product RNA in the cell using a hybridisation assay. This method can be carried out in vitro or ex vivo, for example in cell culture or in cells explanted from a human or animal body. Alternatively, the method can be carried out in vivo, for example where the viral particles are administered to a cell in a human or animal subject before extracting the cells or tissues from the human or animal subject in order to detect the presence of gene product RNA in the cell using a hybridisation assay.
In some embodiments, cells or tissues are extracted from a subject who has been treated with viral particles of the invention in order to examine localisation of the expressed gene product. Such tissue could be obtained, for instance, from epilepsy surgery in the event of epilepsy gene therapy failure, or post-mortem.
The invention also provides an in vitro or ex vivo method of confirming the presence of gene product in a cell that has been obtained from a subject administered with a viral particle described herein, the method comprising detecting the presence of engineered gene product RNA in the cell using a hybridisation assay.
Hybridisation assays are known in the art and generally involve using complementary nucleic acid probes (such as in situ hybridization using labelled probe, Northern blot and related techniques). In some embodiments, the hybridisation assay is an in situ hybridisation assay using a labelled probe, such as a fluorescently labelled probe.
As used herein, the term “probe” refers to a nucleic acid used to detect a complementary nucleic acid. Typically the probe is an RNA probe.
Suitable selective hybridisation conditions for oligonucleotides of 17 to 30 bases include hybridization overnight at 42° C. in 6X SSC and washing in 6X SSC at a series of increasing temperatures from 42 oC to 65 oC. One common formula for calculating the stringency conditions required to achieve hybridization between nucleic acid molecules of a specified sequence homology is (Sambrook et al., 1989): Tm = 81.5 oC + 16.6 Log [Na+] + 0.41 (% G+C) - 0.63 (% formamide) - 600/#bp in duplex.
Any sub-titles herein are included for convenience only, and are not to be construed as limiting the disclosure in any way. The invention will now be further described with reference to the following non-limiting Figures and Examples. Other embodiments of the invention will occur to those skilled in the art in the light of these. The disclosure of all references cited herein, inasmuch as it may be used by those skilled in the art to carry out the invention, is hereby specifically incorporated herein by cross-reference.
One aspect of the invention is a method to treat epilepsy using activity-dependent promoters in order to selectively target the neurons driving seizures, or contributing to propagating seizures, (darker shading in
Some current experimental gene therapies rely on permanent modification of neuronal excitability, for example using a Kv1.1 ion channel under the control of a cell-specific promoter, and which may not discriminate between neurons involved in seizure and healthy neurons (
Neuronal excitation elicits the rapid induction of a set of genes called immediate early genes (IEGs) such as c-Fos and Arc. c-Fos may discriminate between those neurons involved or not in the seizures, as increased expression of c-Fos in specific neurons after seizures has been observed in mouse models, and in human epileptic brains, where c-Fos has a transient expression.
Using a c-Fos promoter in an adeno-associated viral vector enables up-regulation of expression of the effector gene (KCN1A) encoding the potassium channel Kv1.1, which in turn reduces neuronal firing. The increased expression of KCNA1 is predicted to restore normal neuronal behaviour in the epileptic focus. After the circuit activity returns to near-normal levels, the promoter activity decreases and the expression of the potassium channel returns to baseline (
The c-Fos promoter will be activated by a seizure and then switch on immediately, staying on for 6-12 hours. In this lag of time the therapeutic gene will be express and protein transcribed. The protein will stay stable for longer time (KCNA1 is supposed to be stable in the membrane for >96 hrs).
In this case the patients are “protected” from seizures for days, and as many patients experience seizures in clusters, the treatment should reduce the number of seizures experienced within a cluster. Furthermore, a rescue of clustered seizures may lead to a restoration of a physiological state that can result in no more seizures at all.
If other seizures occur later, the system will be switched on again.
Primary mature cortical neurons were stimulated with pro-convulsant drugs and c-fos expression was assessed by immunofluorescence at different time points (2, 6, 24 and 48) after fixation.
A minimal promoter of c-Fos with a part of the 5′UTR and a chimeric intron to boost the expression of the transgene was used. The promoter was then inserted into an AAV backbone with the dsGFP and KCNA1 codon optimised.
Also, a minimal promoter for Arc was used to boost the expression of the transgene. The promoter was inserted into an AAV backbone with KCNJ2.
Also,
Primary cortical neurons were grown on multi-electrode arrays (MEAs) for 21 DIV and transduced at 7 DIV with either AAV c-Fos-dsGFP or AAV c-Fos-dsGFP-KCNA1. Network activity was assessed at 21 DIV. Repeats were n=6 (C-Fos-dsGFP) and n=7 (C-Fos-KCNA1).
Also, primary cortical neurons were grown on multi-electrode arrays (MEAs) for 21 DIV (days in vitro) and transduced at 7 DIV with either AAV c-Fos-dsGFP or AAV c-Fos-dsGFP-KCNA1 or c-Fos-dsGFP-KCNJ2 or mArc-dsGFP-KCNA1 or mArc-dsGFP-KCNJ2 or ESARE-dsGFP-KCNA1. Network activity was assessed at 21 DIV. Repeats were n=6 (C-Fos-dsGFP), n=7 (C-Fos-KCNA1), n=16 (c-Fos-dsGFP-KCNJ2), n=6 (mArc-dsGFP-KCNA1), n=5 (mArc-dsGFP-KCNJ2), and n= 5 (ESARE-dsGFP-KCNA1).
Also,
As discussed in example 5,
Primary cortical neurons were grown on multi-electrode arrays (MEAs) for 21 DIV and transduced at 7 DIV with either AAV c-Fos-dsGFP or AAV c-Fos-dsGFP-KCNA1. Network activity was assessed at 21 DIV, and at different time points (2, 6, 24, 48 hrs) after addition of 30 µM picrotoxin (baseline/ 0 hr). Repeats were n=6 (c-Fos-dsGFP) and n=7 (c-Fos-dsKCNA1).
Also, primary cortical neurons were grown on multi-electrode arrays (MEAs) for 21 DIV and transduced at 7 DIV with either c-Fos-dCAS9-VP64-GFP or c-Fos-dCAS9-VP64-GFP-KCNA1 (2 AAVs). Network activity was assessed at 21 DIV, and at different time points (2, 6, 24,48 hrs) after addition of 30 µM picrotoxin (baseline/ 0 hr). Repeats were n=16 (c-Fos-dCAS9-VP64-GFP) and n=10 (c-Fos-dCAS9-VP64-GFP-KCNA1).
Also,
Acute pilocarpine injections in the visual cortex were performed after viral injection of either AAV Camk2a-GFP or AAV cfos-GFP. Acute pilocarpine injections lead to focal seizures. The spread of the virus and the number of neurons positive for GFP were evaluated.
Because the virus serotype used is the same (AAV9), the spread of transduction is comparable and this provides direct evidence that the treatment will not affect bystander neurons that do not participate in the seizure. Thus, the therapeutic effect is specifically targeted to neurons that become over-activated.
A schematic of the experimental procedure is shown in
A chronic rat model of temporal lobe epilepsy (TLE) was created using intraperitoneal (IP) injection of kainic acid (KA). After 12 weeks EEG transmitters and cannulas were implanted and the rats were recorded continuously for 5 weeks (Baseline). Then, AAV-cfos-dsGFP or AAV-cfos-dsGFP-KCNA1 (as shown in
Acute intraperitoneal Pentylenetetrazole (PTZ) injections were performed after viral injection of either AAV cfos-GFP or c-Fos-dsGFP-KCNJ2 or mArc-dsGFP-KCNA1, mArc-dsGFP-KCNJ2 or ESARE-dsGFP-KCNA1, or ESARE-dsGFP-KCNA1 or NRAM-dsGFP-KCNA1. Acute PTZ injections lead to a single tonic-clonic generalised seizure. The effect on fluorescent cells (activated by the seizure) after >2 hours was evaluated with single cell patch clamp. The experimental setup is shown in
Because the fluorescence is selective to a small subset of neurons, this provides direct evidence that the treatment will not affect bystander neurons that do not participate in the seizure. Thus, the therapeutic effect is specifically targeted to neurons that become over-activated. The transient expression of either KCNA1 or KCNJ2 is enough to reduce neuronal excitability. This provides direct evidence that the treatment selectively decreases the activity of hyperexcitable neurons participating in the seizure.
Two consecutive acute intraperitoneal Pentylenetetrazole (PTZ) injections were performed after viral injection of either AAV cfos-GFP or c-Fos-dsGFP-KCNJ2. Each PTZ injection normally leads to a single tonic-clonic generalised seizure allowing the protective effect of the activity-dependent therapy to be evaluated with the second injection. The experimental set up is shown in
A chronic mouse model of temporal lobe epilepsy (TLE) was created using intra-amygdala injection of kainic acid (KA). After 2 weeks EEG transmitters and cannulas were implanted and the mice were recorded continuously for 2 weeks (Baseline). Then, AAV-cfos-dsGFP or AAV-cfos-dsGFP-KCNA1 (as shown in
These data confirm the self-regulated anti-epileptic effect of the activity-dependent gene therapy.
In some cases, the construct of
Mice were tested for different behaviour using open field, Object Location Test and T-Maze Spontaneous Alternation before and after injection with either AAV-cfos-dsGFP or AAV-cfos-dsGFP-KCNA1.
These data confirm that activity-dependent gene therapy well tolerated.
The following embodiments E1 to E33 also form part of the invention:
E1. An expression vector for use in a method of treatment of a neurological disorder associated with neuronal hyperexcitability in a subject, the vector comprising:
E2. The expression vector for use of E1, wherein the level of expression of the gene product increases when the neuron becomes more excited and decreases when the neuron becomes less excited.
E3. The expression vector for use according to any one of the above embodiments, wherein the promoter is a pyramidal neuronal activity-dependent promoter.
E4. The expression vector for use according to any one of the above embodiments, wherein the promoter is an immediate early gene (IEG) promoter.
E5. The expression vector for use according to any one of the above embodiments, wherein the promoter is c-Fos, Arc, or Egr1.
E6. The expression vector for use according to any one of the above embodiments, wherein the promoter has a nucleotide sequence comprising or consisting of the nucleotide sequence shown in SEQ ID NO: 3 or a nucleotide sequence having at least 80% identity to the nucleotide sequence shown in SEQ ID NO: 3.
E7. The expression vector for use according to any one of the above embodiments, wherein the gene is an ion channel gene, and the gene product is an ion channel.
E8. The expression vector for use according to any one of the above embodiments, wherein the gene is a potassium ion channel gene, and the gene product is a potassium ion channel.
E9. The expression vector for use according to any one of the above embodiments, wherein the gene is a KCNA1 gene, and the gene product is a Kv1.1 potassium channel.
E10. The expression vector for use according to any one of the above embodiments, wherein the gene is an engineered KCNA1 gene, and the gene product is an edited Kv1.1 potassium channel.
E11. The expression vector for use according to any one of the above embodiments, wherein the engineered KCNA1 gene has a nucleotide sequence having at least 90% sequence identity to the nucleotide sequence shown in SEQ ID NO: 1, and
wherein the edited Kv1.1 potassium channel has an amino acid sequence having at least 90% sequence identity to the amino acid sequence shown in SEQ ID NO: 2 and comprises a valine amino acid residue at a position corresponding to amino acid residue 400 shown in SEQ ID NO: 2.
E12. The expression vector for use of any of the above embodiments, wherein the method of treatment is close-loop therapy.
E13. The expression vector for use according to any one of the above embodiments, wherein the neurological disorder is a seizure disorder.
E14. The expression vector for use according to E13, wherein the seizure disorder is epilepsy, optionally neocortical epilepsy, temporal lobe epilepsy or refractory epilepsy.
E15. The expression vector for use according to any one of E1-12, wherein the neurological disorder is Parkinson’s disease, chronic pain, sudden unexpected death in epilepsy (SUDEP), migraine, cluster headache, trigeminal neuralgia, post-herpetic neuralgia, paroxysmal movement disorders, uni- or bipolar affective disorders, anxiety, or phobias.
E16. The expression vector for use according to any one of the above embodiments, wherein the vector is a viral vector.
E17. The expression vector for use according to E16, wherein the viral vector is a recombinant adeno-associated virus (AAV) vector, or a lentiviral vector, optionally wherein the lentiviral vector is a non-integrating lentiviral vector.
E18. The expression vector for use according to E16, wherein the vector comprises a nucleotide sequence having at least 95% identity to the nucleotide sequence of SEQ ID NO: 8, SEQ ID NO: 9 or SEQ ID NO: 10.
E19. An expression vector comprising:
E20 An in vitro method of making viral particles comprising:
E21. An in vitro method of E20, wherein the method comprises transducing the mammalian cells with one or more viral packaging and envelope expression vectors that encode the viral packaging and envelope proteins necessary for particle formation.
E22. An in vitro method of E20 or E21, wherein the one or more packaging proteins includes a non-functional integrase enzyme such that the vector is unable to incorporate its viral genome into the genome of the cell.
E23. An in vitro method of any one of E20-22, further comprising separating the viral particles from the culture medium and optionally concentrating the viral particles.
E24. A viral particle produced by the method of any one of E20-23, the viral particle optionally comprising an RNA molecule or DNA molecule transcribed from the expression vector of any of E1-19.
E25. A viral particle comprising a single stranded RNA molecule or DNA molecule encoding a gene as described in any one of E1-19,
E26. A kit comprising an expression vector of any one of E1-19 and one or more viral packaging and envelope expression vectors that encode viral packaging and envelope proteins necessary for particle formation when expressed in a cell.
E27. A kit of E26, wherein the viral packaging expression vector is an integrase-deficient viral packaging expression vector.
E28. A viral particle of E24 or E25 for use in a method of treatment, wherein the method of treatment is defined in any one of E12-15.
E29. A method of treatment of a neurological disorder as defined in any one of E1 and 12-15, comprising administering to an individual with the neurological disorder the expression vector as defined in any one of E1-19, or the viral particle of E24 or E25.
E30. A method of confirming the presence of a gene product as defined in any one of E1-19, the method comprising:
E31. An in vitro or ex vivo method of confirming the presence of a gene product as defined in any one of E1-19 that has been obtained from a subject administered with a viral particle of E24 or E25, the method comprising:
detecting the presence of the gene product in the cell using a hybridisation assay.
E32. A method of E29 or E30, wherein the hybridisation assay is an in situ hybridisation assay using a labelled RNA probe, optionally wherein the labelled RNA probe is fluorescently labelled.
E33. A cell comprising the expression vector of any one of E1-19.
wherein n is T or C
Amino acid sequence of an edited human Kv1.1 compr
Nucleotide sequence of the cfos promoter (SEQ ID N
Nucleotide sequence of wild-type KCNA1 coding sequ
Amino acid sequence of wild-type human Kv1.1, comp
Nucleotide sequence of cfos-GFP construct (SEQ ID
Nucleotide sequence of cfos-dsGFP-KCNA1 construct
Nucleotide sequence of optimised AAV-cfos-dsGFP-KC
Nucleotide sequence of cfos-KCNA1 construct (SEQ I
Nucleotide sequence of optimised AAV-cfos-KCNA1 ve
Engineered human KCNA1 gene encoding an edited Kv1
Amino acid sequence of an edited human Kv1.1 compr
Nucleotide sequence of an exemplary KCNJ2 gene (SE
Amino acid sequence of Kir2.1 (SEQ ID NO: 14) MGSV
Nucleotide sequence of the mArc promoter (SEQ ID NO
Nucleotide sequence of the ESARE promoter (SEQ ID
Nucleotide sequence of the NRAM-human cFos promote
Nucleotide sequence of the Eqr1 promoter (SEQ ID N
Nucleotide sequence of mArc-dsGFP-KCNA1 construct
Nucleotide sequence of optimised AAV- mArc-dsGFP-K
Nucleotide sequence of mArc-dsGFP-KCNJ2 construct
Nucleotide sequence of optimised AAV- mArc-dsGFP-K
Nucleotide sequence of ESARE-dsGFP-KCNA1 construct
Nucleotide sequence of optimised AAV- ESARE-dsGFP-
Nucleotide sequence of ESARE-dsGFP-KCNJ2 construct
Nucleotide sequence of optimised AAV- ESARE-dsGFP-
Nucleotide sequence of NRAM-hCfos-dsGFP-KCNA1 cons
Nucleotide sequence of optimised AAV- NRAM-hCfos -
Nucleotide sequence of NRAM-hCfos -dsGFP-KCNJ2 con
Nucleotide sequence of optimised AAV- NRAM-hCfos -
Nucleotide sequence of Eqr1-dsGFP-KCNA1 construct
Nucleotide sequence of optimised AAV- Eqr1-dsGFP-K
Nucleotide sequence of Egr1-dsGFP-KCNJ2 construct
Nucleotide sequence of optimised AAV- Egr1-dsGFP-K
Nucleotide sequence of Tet-On-dCAS9VP64 construct
Nucleotide sequence of optimised AAV- Tet-On-dCAS9
Nucleotide sequence of sgRNA KCNA1 (SEQ ID NO: 37)
Nucleotide sequence of sgRNA LacZ (control) (SEQ I
Nucleotide sequence of optimised AAV- sgRNA KCNA1-
Nucleotide sequence of optimised AAV- sgRNA LacZ-c
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004498.8 | Mar 2020 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/058210 | 3/29/2021 | WO |
