Patent Application
20060154870
This invention relates to methods for prevention or treatment of diseases or disorders related to excessive formation of vascular tissue or blood vessels, i.e. any disease or disorder in which angiogenesis is involved. The method is based on the use of targeted inhibition (or blocking) of neuropeptide Y (NPY) Y2 receptor mediated actions. The invention also concerns novel antisense oligonucleotides and their use in said methods as well as novel antisense oligonucleotides and their use in investigating the development of said diseases or disorders in experimental animals.
The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference.
NPY is a neurotransmitter of the sympathetic nervous system, co-stored with noradrenaline in peripheral sympathetic nerve endings and released in response to strenuous sympathetic stimulation (Lundberg, Fried, et al. 1986 (1)). When released from peripheral nerve terminals to arterial periadventitia NPY causes direct endothelium-independent vasoconstriction via stimulation vascular smooth-muscle cell receptors (Edvinsson, Emson, et al. 1983 (2); Edvinsson 1985 (3); Abounader, Villemure, et al. 1995 (4)).
NPY is widely expressed in the central and peripheral nervous systems and has many physiological functions such as in the control of metabolism and endocrine functions and in regulation of cardiovascular homeostasis.
In addition to release from peripheral nerve endings to arterial periadventitia, NPY and NPY mRNA are also expressed extraneuronally in the endothelium of peripheral vessels (Loesch, Maynard, et al. 1992 (5); Zukowska-Grojec, Karwatowska-Prokopczuk, et al. 1998 (6)). The minor proportion of circulating NPY level, derived from the endothelial cells has been implicated to act as an autocrine and paracrine mediator and to stimulate its receptors Y1 and Y2 found on the endothelium (Sanabria and Silva 1994 (7); Jackerott and Larsson 1997 (8); Zukowska-Grojec, Karwatowska-Prokopczuk, et al. 1998 (6). In addition to NPY, the endothelium can also produce NPY[3-36], a more specific Y2 agonist, from circulating native NPY by a serine protease dipeptidyl peptidase IV (Mentlein, Dahms, et al. 1993 (9)). Recent studies have demonstrated that stimulation of endothelial NPY receptors leads to vasodilatation (Kobari, Fukuuchi, et al. 1993 (10); Torffvit & Edvinsson 1997 (11)) primarily through Y2 receptor activation (You, Edvinsson, et al. 2001 (12)). In experimental study settings NPY has shown mitogenic action on smooth muscle tissue and vascular growth promoting properties. Grant and Zukowska demonstrated that NPY is a potent angiogenic factor that has promising potential to the revascularization of ischemic tissue (Grant and Zukowska 2000 (13)). The mitogenic effect of NPY has been speculated to be mediated via Y1 or Y2 receptors (Zukowska-Grojec, Pruszczyk et al. 1993 (14); Nilsson and Edvinsson 2000 (15)) and vascular growth promotion is mediated by inducible Y1, Y2, or Y5 receptors (Zukowska-Grojec Z, Karwatowska-Prokopczuk et al. 1998 (6)).
Angiogenesis is involved in a variety of human diseases. The NPY system and Y2 receptor has been shown to play a role in the regulation of the formation of blood vessels and to be active during the development of retinopathy (Zukowska-Grojec Z, et. al.1998 (6); Lee E W, et al. 2003(16); Ekstrand A J et al. 2003(17)). Thus, identification of agents blocking the NPY mediated action thorough Y2 receptor may have potential applications in the treatment of a variety of human diseases.
It was recently reported that a rather common Leu7Pro polymorphism located in the signal peptide of the prepro-NPY is associated with higher prevalence of diabetic retinopathy in type 2 diabetic patients (Niskanen, Voutilainen-Kaunisto et al. 2000 (18)). This study linked the NPY system with the development of diabetic retinopathy. However, it has not earlier been suggested to treat or prevent such diseases by affecting the NPY Y2 receptor.
According to one aspect, this invention concerns a method for treating or preventing a disease or disorder related to excessive formation of vascular tissue or blood vessels in a patient, said method comprising administering to said patient an agent affecting the NPY Y2 receptor.
According to another aspect, this invention concerns an antisense oligonucleotide having a length ranging from 7 to 40 nuclotides, wherein said antisense oligonucleotide is complementary to any sequence of the human NPY Y2 receptor mRNA.
According to a third aspect, the invention concerns an antisense oligonucleotide having a length ranging from 7 to 40 nuclotides, wherein said antisense oligonucleotide is complementary to any sequence of animal NPY Y2 receptor mRNA.
According to a fourth aspect, the invention concerns a method for investigating the development of a disease or disorder related to excessive formation of vascular tissue or blood vessels in an experimental animal using an antisense oligonucleotide having a length ranging from 7 to 40 nuclotides, wherein said antisense oligonucleotide is complementary to any sequence of animal NPY Y2 receptor mRNA.
According to a fifth aspect, the invention concerns a pharmaceutical composition comprising a therapeutically effective amount of an antisense oligonucleotide or a mixture of antisense oligonucleotides in a pharmaceutically acceptable carrier, said oligonucleotide having a length ranging from 7 to 40 nuclotides and being complementary to any sequence of the human NPY Y2 receptor mRNA.
According to a sixth aspect, the invention concerns an expression vector including a nucleotide sequence encoding an antisense oligonucleotide having a length ranging from 7 to 40 nuclotides and being complementary to any sequence of the human or animal NPY Y2 receptor mRNA, in a manner which allows expression of said antisense oligonucleotide in a mammalian cell.
Our current results conducted using living cells derived from humans demonstrate that the antisense molecules directed against human NPY Y2 receptor mRNA are effective inhibitors of angiogenesis. Thus any compound preventing the NPY Y2 receptor transmission could be a potent inhibitor of tumor angiogenesis, and could have a more general interest in every disease in which angiogenesis is involved.
The wording “disease or disorder related to excessive formation of vascular tissue or blood vessels in a patient” shall be understood to cover any such disease or disorder which can be treated or prevented by an agent to antagonize or block or prevent or modify the action of the NPY Y2 receptor.
Examples of diseases, the treatment of which could be clinically greatly benefited from the down regulation, or blockage of Y2 receptor, or prevention of the action of naive NPY or fragments of NPY (e.g. NPY 3/36 or 13-16, which are endogenous) on Y2 receptor are non-neoplastic pathologic conditions characterized by excessive angiogenesis, such as neovascular glaucoma, any form of retinopathy, all proliferative retinopathies including proliferative diabetic retinopathy, retinopathy of prematurity, macular degeneration, maculopathy, micro- or macrovascular eye complications caused by diabetes, nephropathy, diabetic nephropathy, rubeosis iridis, hemangiomas, angiofibromas, and psoriasis. This method is also effective for treating subjects with tumors and neoplasms, including malignant tumors and neoplasms, such as blastomas, carcinomas or sarcomas, and especially highly vascular tumors and neoplasms. Some examples of tumors that can be treated with the invention include epidermoid tumors, squamous tumors, such as head and neck tumors, colorectal tumors, prostate tumors, breast tumors, lung tumors, including small cell and nonsmall cell lung tumors, pancreatic tumors, thyroid tumors, ovarian tumors, and liver tumors, vascularized skin cancers, including squamous cell carcinoma, basal cell carcinoma, and skin cancers that can be treated by suppressing the growth of neovasculature. Other cancers that can be treated by the method according to this invention include Kaposi's sarcoma, CNS neoplasms (neuroblastomas, capillary hemangioblastomas, meningiomas and cerebral metastases), melanoma, gastrointestinal and renal carcinomas and sarcomas, rhabdomyosarcoma, glioblastoma, preferably glioblastoma multiforme, and leiomyosarcoma.
However, the diseases or disorders are not restricted to the aforementioned list. Furthermore, the wording “disease or disorder related to excessive formation of vascular tissue or blood vessels in a patient” includes further prevention of diseases or disorder directly derivable from the aforementioned conditions. Thus, for example, this wording also includes the prevention of predisposition to vision loss and blindness, which are consequences of retinopathy. Also metabolic diseases and cardiovascular diseases are included.
The diseases or disorders to be prevented or treated according to the method of this invention are particularly retinopathies or retinal neovascularization processes in diabetes like type I or type II diabetes, other metabolic diseases or cardiovascular diseases.
The term “NPY Y2 receptor” shall be understood to mean a receptor encoded by NPY Y2 receptor gene and mRNA (Gehlert, Beavers et al. 1996 (19); Rose P M, Fernandes et al. 1995 (20)) or active for NPY or a peptide fragment of NPY. Such a fragment can, for example, be the peptide fragment of NPY3-36, NPY13-36 (Wimalawansa 1995 (21), Grandt el al. 1996 (22)) or N-acetyl [Leu(28,31)] NPY 24-36 (Smith-White and Potter 1999 (23)) or the like.
The term “agent” shall be understood to include the compound itself (racemic form as well as isomers), and any pharmaceutically acceptable derivatives thereof, such as salts or esters and templates. It shall be also understood to include peptide compounds and derivatives antagonising NPY Y2 receptor. It shall be also understood to include agents that direct the action of endogenous NPY Y2 receptor agonists and ligands away from NPY Y2 receptor, thus attenuating NPY Y2 receptor action. It shall be also understood to include any agent aimed at influencing any phases of NPY Y2 receptor transcription and translation processes, and any device or instrument (genetic or other) needed for this mentioned action.
The active agent to be administered can in principle be either an NPY Y2 antagonist, or a combination of an antagonist in a said NPY Y2 receptor and an agonist or an antagonist in another receptor, for example in NPY Y5 receptor. The same agent can thus be an antagonist in said NPY Y2 receptor and an agonist or an antagonist in another receptor. The same agent can thus be also a partial agonist.
According to a preferable embodiment of this invention, the agent is an NPY receptor antagonist. Y2 receptor antagonists have been described before in the literature. As an example can be mentioned BIIE 0246 (Doods, Gaida et al 1998 (24)). The suitable agent is, however, not restricted to the aforementioned examples. Any compound acting as a Y2 receptor antagonist is useful in the method according to this invention.
It is also believed that an agent blocking or influencing/inhibiting the action of dipeptidyl peptidase IV and therefore prevention of the catabolism of NPY to NPY3-36 and the action of NPY3-36 and native NPY towards NPY Y2 receptor could be useful. As an example can be mentioned Dipeptidyl Peptidase IV Inhibitor P32/98 (Pospisilik, Stafford et al. 2002 (25)) and dipeptidyl peptidase IV inhibitor isoleucine thiazolidide (Rahfeld J, Schierhorn et al 1991 (26)). The suitable agent is, however, not restricted to the aforementioned examples. Alternatively, an antisense oligonucleotide, an aptamer or an antibody directed to dipeptidyl peptidase IV would also be useful.
It is also believed that a combination of action on the Y1 and Y5 receptor in addition to Y2 antagonism and could be useful.
An Y2-receptor antagonistic molecule with a property of intrinsic NPY receptor stimulating activity on Y1- and or Y5-receptors, which by acting on NPY Y2 and/or Y1 and/or Y5-receptors prevents the development and progression of retinopathy and nephropathy, and which blocks inappropriate (excessive) vasculoproliferative actions (potential retinopathy and nephropathy and related conditions promoting effects of excess endogenous NPY) of endogenous NPY and growth hormone and insulin like growth factor-I. Thus it is also believed that antagonising NPY Y2 action prevents the development and progression of retinopathy and nephropathy through reducing growth hormone and insulin like growth factor-I.
Thus, according to another embodiment of this invention the Y2 receptor antagonist is also a Y1 or/and Y5-receptor agonist or antagonist.
According to a further embodiment, a separate Y1 and/or Y5 receptor agonist or antagonist is administered in combination with the Y2 receptor agonist.
According to further embodiments, this invention also concerns any method by which the prevention or down regulation of the action of NPY Y2 receptor is possible such a the use of an antisense oligonucleotide, modified nucleotide, sequence of combination of different kinds of nucleotides or any other sequence able to antagonize the action of NPY Y2 receptor or prevent or modify the NPY Y2 receptor synthesis, modification, activity, ligand binding, metabolism or degradation. The antisense oligonucleotide can be a DNA molecule or an RNA molecule. Ribozymes cleaving the NPY Y2 receptor mRNA are also included.
The ribozyme technology is described for example in the following publications: Ribozyme protocols: Turner, Philip C (editor) (27); Rossi J J. 1999 (28); and Ellington A D, Robertson M P, Bull J. 1997 (29).
Also small interfering RNA molecules would be useful (30).
According to a further alternative, the agent affecting the NPY Y2 receptor can be an antibody raised against said receptor or raised against an Y2-specific epitope on the NPY peptide. NPY receptor specific antibodies are known in the art, but they have been used only to study the distribution of the Y2-receptor and other NPY receptors.
According to still another alternative, the agent affecting the NPY Y2 receptor can be an aptamer affecting the Y2 receptor or a Y2-specific NPY-conformation. An aptamer is an oligonucleotide affecting the protein. Many antisense oligonucleotides have also the ability to interact with peptides. There are known NPY aptamers affecting the Y2-specific NPY-conformation and thereby preventing the NPY from binding to the Y2 receptor. Also aptamers affecting the NPY receptor are known. For publications relating to aptamers, see references 31-33.
The novel antisense oligonucleotides complementary to any sequence of the human or animal NPY Y2 receptor mRNA, which according to the broadest definition can be of a length ranging from 7 to 40 nucleotides, have preferably a length ranging from 15 to 25 nucleotides, most preferably about 20 nucleotides.
The term “complementary” means that the antisense oligonucleotide sequence can form hydrogen bonds with the target mRNA sequence by Watson-Crick or other base-pair interactions. The term shall be understood to cover also sequences which are not 100% complementary. It is believed that lower complementarity, even as low as 50% or more, may work. However, 100% complementarity is preferred.
In
Normal, unmodified antisense oligonucleotides have low stability under physiological conditions because of its degradation by enzymes present in the living cell. It is therefore highly desirable to modify the antisense oligonucleotide according to known methods so as to enhance its stability against chemical and enzymatic degradation.
Modifications of antisense oligonucleotides are extensively disclosed in prior art. Reference is made to Draper et al., U.S. Pat. No. 5,612,215, which in turn lists a number of patents and scientific papers concerning this technique. It is known that removal or replacement of the 2′-OH group from the ribose unit gives a better stability. Eckstein et al., WO 92/07065 and U.S. Pat. No. 5,672,695 discloses the replacement of the ribose 2′-OH group with halo, amino, azido or sulfhydryl groups. Sproat et al., U.S. Pat. No. 5,334,711, discloses the replacement of hydrogen in the 2′-OH group by alkyl or alkenyl, preferably methyl or allyl groups. Furthermore, the internucleotidic phosphodiester linkage can, for example, be modified so that one ore more oxygen is replaced by sulfur, amino, alkyl or alkoxy groups. Preferable modification in the internucleotide linkages are phosphorothioate linkages. Also the base in the nucleotides can be modified. Usman and Blatt, 2000 (35), disclose a new class of nuclease-resistant ribozymes, where the 3′ end of the antisense oligonucleotide is protected by the addition of an inverted 3′-3′ deoxyabasic sugar.
A preferable antisense oligonucleotide is a nucleotide chain wherein one or more of the internucleotide linkages are modified, and/or wherein the oligonucleotide contains locked nucleic acid (LNA) modifications and/or wherein the oligonucleotide contains peptide nucleic acid (PNA) modifications. Margaret F Taylor, 2001 (36) discloses a great variety of modifications. According to this publication, the sugar unit can, for example also be replaced by a morpholino group. This publication further discloses that different kinds of modifications inhibits the mRNA translation in different ways. All kinds of modifications described in this article are incorporated herein by reference.
The PNA technology is described in Ray A and Norden, 2000 (37).
Another preferable antisense oligonucleotide is a nucleotide chain wherein one or more of the sugar units are modified, and/or one or more of the internucleotide linkages are modified, and/or one or more of the bases are modified and/or the oligonucleotide is end-protected by an inverted deoxyabasic sugar.
As an example of preferred embodiments can be mentioned any NPY Y2 receptor targeted sequence of antisense deoxynucleotide phosphorothioates or oligonucleotides containing locked nucleic acids or peptide nucleic acids or ribozyme. Specific preferable examples are AS-1, which is 5′-CCT CTG CAC CTA TTG GAC CC-3′ (SEQ ID NO:2); AS-2, which is 5′-GTTTGTGGCCCGTATTGTTCC-3′, (SEQ ID NO:3) and AS-3, which is 5′-GGCCACTGTTCTTTCTGACC-3′, (SEQ ID NO:4) or longer sequences comprising these chains of nucleotides. All antisense sequences that can recognize and bind any part of the human NPY Y2 receptor mRNA sequence, including all occurring variations due to polymorphism in the human NPY Y2 receptor gene are also concerned.
As further examples of useful antisenses can be mentioned the sequences listed below (SEQ ID NO:7 to SEQ ID NO:37):
Combinations of antisenses are also useful. Two or more of the antisense sequences SEQ ID NOs:2-4 or SEQ ID NOs:7-37 can be used, or any of these sequences can be used in combination with other antisense oligonucleotides such as human vascular endothelial growth factor antisense (VEGF-AS, 5′-GCCTCGGCTTGTCACATCTGC-3′, (SEQ ID NO:41).
The suitable agent is, however, not restricted to the aforementioned examples. Any compound acting as a Y2 receptor antagonist or attenuating Y2 receptor action is useful in the method according to this invention.
According to a further embodiment, this invention also concerns a novel antisense oligonucleotide having a length ranging from 7 to 40 nucleotides, wherein said antisense oligonucleotide is complementary to any sequence of animal NPY Y2 receptor mRNA. The experimental animal is preferable a rodent such as a rat or mouse. The term “complementary” shall have the same meaning as presented above for the human sequence.
These antisense oligonucleotides preferably contains one or more modifications as described above.
The invention concerns methods for investigating the development of a disease or disorder related to excessive formation of vascular tissue or blood vessels, particularly any form of retinopathy, in an experimental animal using such antisense oligonucleotides complementary to animal NPY Y2 receptor mRNA.
As an example can be mentioned any NPY Y2 receptor targeted sequence of antisense deoxynucleotide phosphorothioates or oligonucleotides containing locked nucleic acids or peptide nucleic acids or ribozyme. As an example of the sequence is a sequence containing 5′-CCT CTG CAC CTA ATG GGC CC-3′ (SEQ ID NO:38) corresponding to rat NPY Y2 mRNA. The suitable agent is, however, not restricted to the aforementioned example.
For the purpose of this invention, the NPY receptor active agent can be administered by various routes. The suitable administration forms include, for example, oral or topical formulations; parenteral injections including intraocular, intravitreous, intravenous, intramuscular, intraperitoneal, intradermal and subcutaneous injections; and transdermal, intraurethral or rectal formulations; and inhaled and nasal formulations. Suitable oral formulations include e.g. conventional or slow-release tablets and gelatine capsules.
The antisense oligonucleotides according to this invention can be administered to the individual by various methods. According to one method, the sequence may be administered as such, as complexed with a cationic lipid, packed in a liposome, incorporated in cyclodextrins, bioresorbable polymers or other suitable carrier for slow release adiministration, biodegradable nanoparticle or a hydrogel. For some indications, antisense oligonucleotides may be directly delivered ex vivo to cells or tissues with or without the aforementioned vehicles.
In addition to direct delivery of the antisense oligonucleotide, an antisense oligonucleotide-encoding sequence can be incorporated into an expression vector, and said vector administered to the patient. The expression vector can be a DNA sequence, such as a DNA plasmid capable of eukaryotic expression, or a viral vector. Such a viral vector is preferably based on an adenovirus, an alphavirus, an adeno-associated virus, a retrovirus or a herpes virus. Preferably, the vector is delivered to the patient in similar manner as the antisense oligonucleotide described above. The delivery of the expression vector can be systemic, such as intravenous, intramuscular or intraperitoneal administration, or local delivery to target tissue.
The required dosage of the NPY receptor active agents will vary with the particular condition being treated, the severity of the condition, the duration of the treatment, the administration route and the specific compound being employed.
The invention will be illuminated by the following non-restrictive Experimental Section.
Experimental Section
The present study was undertaken to determine the impact of NPY Y2 receptor targeted intervention on neovascularization and development of retinopathy. Development of retinopathy was induced to newborn rats by cyclic hyperoxia and following relative ischemia-induced retinal neovascularization. Hyperoxemia is toxic to developing retinal vessels causing damage and hypoxia in the retina. After moving to normal air, relative hypoxia follows further promoting neovascularization of the retina.
Three groups of rat puppies were subjected for different treatments; 1) vehicle, 2) NPY Y2 receptor targeted antisense oligonucleotide sequence, and 3) scramble oligonucleotide sequence containing the same oligonucleotides as NPY Y2 receptor targeted antisense oligonucleotide sequence. The treatments were administered intraperitoneally. The retinal vessels were investigated and retinopathic changes were compared between treatment groups.
Retinopathy was assessed after injection of fluorescent-labelled dextran to the circulation. The eyes were flat-mounted on slides and the retinal vessels were visualized and investigated by fluorescence microscopy. Statistical differences were calculated between the study groups.
Retinal Neovascularization Protocol
Study protocol was approved by the Joint Ethics Committee of Turku University. Development of retinopathy was induced to newborn rats (Sprague Dawley) by cyclic hyperoxia and following relative ischemia. Hyperoxia is toxic to developing retinal vessels causing damage and hypoxia in the retina, which induces neovascularization. After moving to normal air, relative hypoxia follows further promoting neovascularization of the retina. Hypoxia is one of the major causes of retinal neovascularization in human retinopathies also. The newborn rats were kept in a hyperoxic incubator with their mothers. Retinal neovascularization was induced simultaneously for all three groups of puppies. One treatment group consisted originally of 7 puppies, which underwent cyclic hyperoxia at the age of 3 days, continued until at the age of 14 days and remained in normal room air from the age of 14 to 17 days. The amount of oxygen inside the incubator was kept at 40% and 80% in 12 hour cycles for 10 days (days from 3 to 13).
Treatments
The three groups of puppies were subjected for different treatments; 1) plain vehicle, 2) NPY Y2 receptor targeted antisense oligodeoxynucleotide sequence (5′-CCT CTG CAC CTA ATG GGC CC-3′ (SEQ ID NO:38), containing 20 thioate modified bases) diluted in vehicle and 3) scramble oligodeoxynucleotide sequence containing the same deoxynucleotides as NPY Y2 receptor targeted antisense oligodeoxynucleotide sequence but in a random order (5′-CCA TGG TAA TCC GCC GCT CC-3′ (SEQ ID NO:39), containing 20 thioate modified bases) diluted in vehicle. The treatments were administered intraperitoneally. The retinal vessels were investigated and retinopathic changes were compared between treatment groups. The used NPY Y2 receptor targeted antisense deoxynucleotide sequence was designed complementary to next 20 bases from NPY Y2 gene transcription initiation codon (ATG).
Assessment of Retinopathy and Retinal Neovascularization
At the age of 20 days, rats were decapitated and eyes were collected. Retinopathy and retinal neovascularization was assessed after an injection of fluorescent-labelled dextran to the circulation trough heart puncture. One eye from each puppy was used for visualization of retinal vessels. The eyes were flat-mounted on slides and the retinal vessels were visualized and investigated by fluorescence microscopy. Pictures of retinas were acquired using a Leica DMR/DC100 microscope and Leica DC Wiever software.
Statistical Methods
The amount of retinal capillaries was analyzed by counting the amount of vessels crossed by a constant length line using plot profile analysis (Image-J 2.6 program). Each retina was analyzed in 3-5 representative areas and the mean values were used for further statistical analysis. Only unfolded retinal preparations were used in order to avoid artificial images of neovascularization. Five eyes from study group 1, and four eyes from study groups 2 and 3 were found unfolded and used for fluorescence microscopy and statistical analyses. Differences between study populations were calculated using Oneway anova followed by post hoc tests (Tukey HSD). P-value les than 0.05 was considered statistically significant. The results are expressed as mean ±SD and range.
Results
Retinal neovascularization and retinopathy was statistically significantly different between the treatment groups (p<0.001, Oneway anova). In vehicle and scramble treatment groups, the fluorescein images showed clearly an irregular and disrupted retinal capillary vessel formation, which was accompanied with blurred fluorescent emitting areas (
Table 1 below shows the mean values of quantitated neovascularization, representing retinopathy, in the three different study groups. The development of retinopathy was evident in vehicle and scramble treated groups of puppies, whereas prevented in NPY Y2 antisense treated group.
*Tukey HSD, compared to Vehicle.
#Tukey HSD, compared to Scramble.
This study demonstrates that development of retinopathy and retinal neovascularizations can be prevented by NPY Y2-receptor targeted oligonucleotide antisense therapy, evidenced by comparison to plain vehicle and control non Y2-antisense deoxyoligonucleotide sequence. The result of this study first time emphasizes the role of NPY Y2-receptor in the treatment and prevention of retinopathy and retinal neovascularization.
Our finding of prevention of retinopathy and inappropriate vascular proliferation with NPY Y2 receptor targeted antisense therapy is novel. Only one previous study has linked NPY-system and potentially altered NPY action with diabetic retinopathy (Niskanen, Voutilainen-Kaunisto et al. 2000 (18)). This finding is of therapeutic potential for prevention and treatment of diabetic retinopathy and closely related diseases due to inappropriate vascular proliferation. Therefore diabetic nephropathy is also potentially preventable and treatable with NPY Y2 receptor targeted therapy, since diabetic nephropathy is also associated with in appropriate vessel growth and vascular tissue mitogenesis (Del Prete, Anglani et al. 1998 (38)). In addition, elevated immunoreactive NPY concentrations has been associated with diabetic nephropathy (Satoh, Satoh et al. 1999 (39)).
Hypoxia induce vascular proliferation is commonly used experimental model for studying the mechanisms involved in pathophysiology of retinopathy and effects of novel therapies to treat and prevent retinopathy (Smith, Shen et al. 1999 (40); Smith, Kopchick et al. 1997 (41); Ozaki, Seo et al. 2000 (42)). The used retinopathy model has its limitations but can be considered sufficient and useful in order to elucidate receptor level mechanisms leading to and involved in the patophysiology of variety of retinopathies, since vascular damage and ischemia are essentially involved in the development of retinal neovascularization in all retinopathies. Preventing NPY Y2 receptor action blocks retinal neovascularization and is therefore an excellent target for treatment of diabetes associated retinopathy, other proliferative retinopathies like retinopathy of prematurity and other ischemic retinopathies.
A further experiment was carried out in order to study the effect of single antisense molecules and their combinations in the prevention of endothelial cell tube formation by immortal human umbilical vein endothelial cells (hTERT-HUVECs).
Cell Culture
Immortal human umbilical vein endothelial cells (hTERT-HUVECs) were obtained from Geron Corporation (Menlo Park, Calif., U.S.A.). hTERT-HUVECs were maintained on a gelatin-coated 100-mm dishes (Coming Costar, N.Y., U.S.A) in growth medium, composed of M199 medium (Gibco, Paisley, Scotland) supplement with 15% (v/v) heat-inactivated fetal bovine serum (Gibco BRL), 2 mM L-glutamine (Gibco BRL), 100 units/ml penicillin/streptomycin (Gibco BRL), 10 units/ml heparin (Sigma) and 20 μg/ml endothelial cell growth factor (Roche Biomolecules) at 37° C. in a humified incubator with 5% CO2 atmosphere. Experiments were performed with cells between passages 20 and 24.
Oligonucleotides
The following phosphorothioate oligonucleotides were synthesized: human neuropeptide Y2-receptor mRNA antisense molecules (AS-1, namely 5′-CCTCTGCACCTATTGGACCC-3′, (SEQ ID NO:2); AS-2, namely 5′-GTTTGTGGCCCGTATTGTTCC-3′, (SEQ ID NO:3); AS-3, namely 5′-GGCCACTGTTCTTTCTGACC-3′, (SEQ ID NO:4); AS-1 control, sequence: 5′-CCCAGGTTATCCACGTCTCC-3′ (SEQ ID NO:40), and human vascular endothelial growth factor antisense (VEGF-AS, sequence: 5′-GCCTCGGCTTGTCACATCTGC-3′, (SEQ ID NO:41)).
Liposomes
N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethyl ammonium methylsulfate (DOTAP) and 1,2-dioleoyl-3-phosphatidylethanolamine (DOPE) were purchased from Avanti Polar Lipids. Cationic liposomes composed of DOTAP/DOPE (1:1 by mol) were prepared as previously described (Ruponen et al., 2001 (43)).
Transfection Protocol
hTERT-HUVECs (5×104 cells/well) were seeded onto gelatin-coated 48-multiwell plates (Coming Costar, N.Y., U.S.A) and incubated overnight. For transfection, the growth medium was replaced with 400 μl of transfection medium (M199 medium supplement with 2 mM L-glutamine and 100 units/ml penicillin/ streptomycin). Oligonucleotides (final concentration 1 μM) and DOTAP/DOPE liposomes in sterile water were first diluted in MES-HEPES buffered saline (50 mM MES, 50 mM HEPES, 75 mM NaCl, pH 7.2) and then mixed together at a charge ratio +1. The transfection mixture was allowed to stand at room temperature for 20 min and the oligonucleotide/liposome complexes (100 μl) were added dropwise to each well.
Endothelial Tube Formation Assay
After transfection for 4 h hTERT-HUVECs were harvested after trypsin treatment, suspended in growth medium (200 μl) and seeded in growth factor-reduced Matrigel (BD Biosciences) coated 96-well plates (Coming Costar, N.Y., U.S.A). After incubation for 3 h cells were fixed in 4% paraformaldehyde. The formation of tubular structures in each well (7 fields/well) was digitally captured using a Nicon Eclipse TE300 Inverted Microscope (Nicon, Tokyo, Japan) equipped with a Nicon F-601 digital camera (Nicon, Tokyo, Japan). Photographs were taken at 4× magnification.
The efficacy in prevention of formation of tubular structures by hTERT-HUVECs of all 5 synthesized antisense molecules were compared against each others alone and in combination. The number of tubular structures was analyzed by using Adobe Photoshop 5.5 (Adobe Systems Inc., San Jose, Calif., U.S.A) and the results were expressed as means ±SEM of three independent experiments. A set of three experiments was repeated.
Results
It will be appreciated that the methods of the present invention can be incorporated in the form of a variety of embodiments, only a few of which are disclosed herein. It will be apparent for the expert skilled in the field that other embodiments exist and do not depart from the spirit of the invention. Thus, the described embodiments are illustrative and should not be construed as restrictive.
The present application is a divisional of U.S. patent application Ser. No. 10/462,039 filed on 16 Jun. 2003, which in turn is related to and claims priority under 35 U.S.C. § 119(e) to U.S. provisional patent application Ser. No. 60/509,044 filed 27 Jun. 2002, each incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60509044 | Jun 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10462039 | Jun 2003 | US |
| Child | 11372212 | Mar 2006 | US |
