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Sample records for retinal gene therapy

  1. Nanoparticles for Retinal Gene Therapy

    PubMed Central

    Conley, Shannon M.; Naash, Muna I.

    2010-01-01

    Ocular gene therapy is becoming a well-established field. Viral gene therapies for the treatment of Leber’s congentinal amaurosis (LCA) are in clinical trials, and many other gene therapy approaches are being rapidly developed for application to diverse ophthalmic pathologies. Of late, development of non-viral gene therapies has been an area of intense focus and one technology, polymer-compacted DNA nanoparticles, is especially promising. However, development of pharmaceutically and clinically viable therapeutics depends not only on having an effective and safe vector but also on a practical treatment strategy. Inherited retinal pathologies are caused by mutations in over 220 genes, some of which contain over 200 individual disease-causing mutations, which are individually very rare. This review will focus on both the progress and future of nanoparticles and also on what will be required to make them relevant ocular pharmaceutics. PMID:20452457

  2. What Is Next for Retinal Gene Therapy?

    PubMed

    Vandenberghe, Luk H

    2015-04-15

    The field of gene therapy for retinal blinding disorders is experiencing incredible momentum, justified by hopeful results in early stage clinical trials for inherited retinal degenerations. The premise of the use of the gene as a drug has come a long way, and may have found its niche in the treatment of retinal disease. Indeed, with only limited treatment options available for retinal indications, gene therapy has been proven feasible, safe, and effective and may lead to durable effects following a single injection. Here, we aim at putting into context the promise and potential, the technical, clinical, and economic boundaries limiting its application and development, and speculate on a future in which gene therapy is an integral component of ophthalmic clinical care. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  3. Clinical applications of retinal gene therapy.

    PubMed

    Lipinski, Daniel M; Thake, Miriam; MacLaren, Robert E

    2013-01-01

    Many currently incurable forms of blindness affecting the retina have a genetic etiology and several others, such as those resulting from retinal vascular disturbances, respond to repeated, potentially indefinite administration of molecular based treatments. The recent clinical advances in retinal gene therapy have shown that viral vectors can deliver genes safely to the retina and the promising initial results from a number of clinical trials suggest that certain diseases may potentially be treatable. Gene therapy provides a means of expressing proteins within directly transduced cells with far greater efficacy than might be achieved by traditional systemic pharmacological approaches. Recent developments have demonstrated how vector gene expression may be regulated and further improvements to vector design have limited side effects and improved safety profiles. These recent steps have been most significant in bringing gene therapy into the mainstream of ophthalmology. Nevertheless translating retinal gene therapy from animal research into clinical trials is still a lengthy process, including complexities in human retinal diseases that have been difficult to model in the laboratory. The focus of this review is to summarize the genetic background of the most common retinal diseases, highlight current concepts of gene delivery technology, and relate those technologies to pre-clinical and clinical gene therapy studies.

  4. [Gene therapy for inherited retinal dystrophies].

    PubMed

    Côco, Monique; Han, Sang Won; Sallum, Juliana Maria Ferraz

    2009-01-01

    The inherited retinal dystrophies comprise a large number of disorders characterized by a slow and progressive retinal degeneration. They are the result of mutations in genes that express in either the photoreceptor cells or the retinal pigment epithelium. The mode of inheritance can be autosomal dominant, autosomal recessive, X linked recessive, digenic or mitochondrial DNA inherited. At the moment, there is no treatment for these conditions and the patients can expect a progressive loss of vision. Accurate genetic counseling and support for rehabilitation are indicated. Research into the molecular and genetic basis of disease is continually expanding and improving the prospects for rational treatments. In this way, gene therapy, defined as the introduction of exogenous genetic material into human cells for therapeutic purposes, may ultimately offer the greatest treatment for the inherited retinal dystrophies. The eye is an attractive target for gene therapy because of its accessibility, immune privilege and translucent media. A number of retinal diseases affecting the eye have known gene defects. Besides, there is a well characterized animal model for many of these conditions. Proposals for clinical trials of gene therapy for inherited retinal degenerations owing to defects in the gene RPE65, have recently received ethical approval and the obtained preliminary results brought large prospects in the improvement on patient's quality of life.

  5. Gene therapy for inherited retinal degenerations.

    PubMed

    Dalkara, Deniz; Sahel, José-Alain

    2014-03-01

    Gene therapy is quickly becoming a reality applicable in the clinic for inherited retinal diseases. Progress over the past decade has moved proof-of-concept gene therapies from bench to bedside. The remarkable success in safety and efficacy, in the phase I/II clinical trials for the form of the severe childhood-onset blindness, Leber's Congenital Amaurosis (LCA) type II (due to mutations in the RPE65 gene) generated significant interest and opened up possibilities for a new era of retinal gene therapies. Success in these clinical trials was due to combining the favorable features of both the retina as a target organ and adeno-associated virus (AAV) as a vector. The retina offers several advantages for gene therapy approaches. It is an anatomically defined structure that is readily accessible for therapy and has some degree of immune privilege, making it suitable for application of viral vectors. AAV, on the other hand, is a non-pathogenic helper dependent virus that has little immunogenicity. This viral vector transduces quiescent cells efficiently and thanks to its small size diffuses well in the interneural matrix, making it suitable for applications in neural tissue. Building on this initial clinical success with LCA II, we have now many opportunities to extend this proof-of-concept to other retinal diseases. This article will discuss what are some of the most imminent targets for such therapies and what are the challenges that we face in moving these therapies to the clinic.

  6. A Comprehensive Review of Retinal Gene Therapy

    PubMed Central

    Boye, Shannon E; Boye, Sanford L; Lewin, Alfred S; Hauswirth, William W

    2013-01-01

    Blindness, although not life threatening, is a debilitating disorder for which few, if any treatments exist. Ocular gene therapies have the potential to profoundly improve the quality of life in patients with inherited retinal disease. As such, tremendous focus has been given to develop such therapies. Several factors make the eye an ideal organ for gene-replacement therapy including its accessibility, immune privilege, small size, compartmentalization, and the existence of a contralateral control. This review will provide a comprehensive summary of (i) existing gene therapy clinical trials for several genetic forms of blindness and (ii) preclinical efficacy and safety studies in a variety of animal models of retinal disease which demonstrate strong potential for clinical application. To be as comprehensive as possible, we include additional proof of concept studies using gene replacement, neurotrophic/neuroprotective, optogenetic, antiangiogenic, or antioxidative stress strategies as well as a description of the current challenges and future directions in the ocular gene therapy field to this review as a supplement. PMID:23358189

  7. Prospectives for gene therapy of retinal degenerations.

    PubMed

    Thumann, Gabriele

    2012-08-01

    Retinal degenerations encompass a large number of diseases in which the retina and associated retinal pigment epithelial (RPE) cells progressively degenerate leading to severe visual disorders or blindness. Retinal degenerations can be divided into two groups, a group in which the defect has been linked to a specific gene and a second group that has a complex etiology that includes environmental and genetic influences. The first group encompasses a number of relatively rare diseases with the most prevalent being Retinitis pigmentosa that affects approximately 1 million individuals worldwide. Attempts have been made to correct the defective gene by transfecting the appropriate cells with the wild-type gene and while these attempts have been successful in animal models, human gene therapy for these inherited retinal degenerations has only begun recently and the results are promising. To the second group belong glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). These retinal degenerations have a genetic component since they occur more often in families with affected probands but they are also linked to environmental factors, specifically elevated intraocular pressure, age and high blood sugar levels respectively. The economic and medical impact of these three diseases can be assessed by the number of individuals affected; AMD affects over 30 million, DR over 40 million and glaucoma over 65 million individuals worldwide. The basic defect in these diseases appears to be the relative lack of a neurogenic environment; the neovascularization that often accompanies these diseases has suggested that a decrease in pigment epithelium-derived factor (PEDF), at least in part, may be responsible for the neurodegeneration since PEDF is not only an effective neurogenic and neuroprotective agent but also a potent inhibitor of neovascularization. In the last few years inhibitors of vascularization, especially antibodies against vascular endothelial cell

  8. Prospectives for Gene Therapy of Retinal Degenerations

    PubMed Central

    Thumann, Gabriele

    2012-01-01

    Retinal degenerations encompass a large number of diseases in which the retina and associated retinal pigment epithelial (RPE) cells progressively degenerate leading to severe visual disorders or blindness. Retinal degenerations can be divided into two groups, a group in which the defect has been linked to a specific gene and a second group that has a complex etiology that includes environmental and genetic influences. The first group encompasses a number of relatively rare diseases with the most prevalent being Retinitis pigmentosa that affects approximately 1 million individuals worldwide. Attempts have been made to correct the defective gene by transfecting the appropriate cells with the wild-type gene and while these attempts have been successful in animal models, human gene therapy for these inherited retinal degenerations has only begun recently and the results are promising. To the second group belong glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy (DR). These retinal degenerations have a genetic component since they occur more often in families with affected probands but they are also linked to environmental factors, specifically elevated intraocular pressure, age and high blood sugar levels respectively. The economic and medical impact of these three diseases can be assessed by the number of individuals affected; AMD affects over 30 million, DR over 40 million and glaucoma over 65 million individuals worldwide. The basic defect in these diseases appears to be the relative lack of a neurogenic environment; the neovascularization that often accompanies these diseases has suggested that a decrease in pigment epithelium-derived factor (PEDF), at least in part, may be responsible for the neurodegeneration since PEDF is not only an effective neurogenic and neuroprotective agent but also a potent inhibitor of neovascularization. In the last few years inhibitors of vascularization, especially antibodies against vascular endothelial cell

  9. Retinal Gene Therapy: Current Progress and Future Prospects

    PubMed Central

    Ku, Cristy A.; Pennesi, Mark E.

    2015-01-01

    Clinical trials treating inherited retinal dystrophy caused by RPE65 mutations had put retinal gene therapy at the forefront of gene therapy. Both successes and limitations in these clinical trials have fueled developments in gene vectors, which continue to further advance the field. These novel gene vectors aim to more safely and efficiently transduce retinal cells, expand the gene packaging capacity of AAV, and utilize new strategies to correct the varying mechanisms of dysfunction found with inherited retinal dystrophies. With recent clinical trials and numerous pre-clinical studies utilizing these novel vectors, the future of ocular gene therapy continues to hold vast potential. PMID:26609316

  10. Gene replacement therapy for retinal CNG channelopathies.

    PubMed

    Schön, Christian; Biel, Martin; Michalakis, Stylianos

    2013-10-01

    Visual phototransduction relies on the function of cyclic nucleotide-gated channels in the rod and cone photoreceptor outer segment plasma membranes. The role of these ion channels is to translate light-triggered changes in the second messenger cyclic guanosine 3'-5'-monophosphate levels into an electrical signal that is further processed within the retinal network and then sent to higher visual centers. Rod and cone photoreceptors express distinct CNG channels. The rod photoreceptor CNG channel is composed of one CNGB1 and three CNGA1 subunits, whereas the cone channel is formed by one CNGB3 and three CNGA3 subunits. Mutations in any of these channel subunits result in severe and currently untreatable retinal degenerative diseases like retinitis pigmentosa or achromatopsia. In this review, we provide an overview of the human diseases and relevant animal models of CNG channelopathies. Furthermore, we summarize recent results from preclinical gene therapy studies using adeno-associated viral vectors and discuss the efficacy and translational potential of these gene therapeutic approaches.

  11. Progress in gene targeting and gene therapy for retinitis pigmentosa

    SciTech Connect

    Farrar, G.J.; Humphries, M.M.; Erven, A.

    1994-09-01

    Previously, we localized disease genes involved in retinitis pigmentosa (RP), an inherited retinal degeneration, close to the rhodopsin and peripherin genes on 3q and 6p. Subsequently, we and others identified mutations in these genes in RP patients. Currently animal models for human retinopathies are being generated using gene targeting by homologous recombination in embryonic stem (ES) cells. Genomic clones for retinal genes including rhodopsin and peripherin have been obtained from a phage library carrying mouse DNA isogenic with the ES cell line (CC1.2). The peripherin clone has been sequenced to establish the genomic structure of the mouse gene. Targeting vectors for rhodopsin and peripherin including a neomycin cassette for positive selection and thymidine kinase genes enabling selection against random intergrants are under construction. Progress in vector construction will be presented. Simultaneously we are developing systems for delivery of gene therapies to retinal tissues utilizing replication-deficient adenovirus (Ad5). Efficacy of infection subsequent to various methods of intraocular injection and with varying viral titers is being assayed using an adenovirus construct containing a CMV promoter LacZ fusion as reporter and the range of tissues infected and the level of duration of LacZ expression monitored. Viral constructs with the LacZ reporter gene under the control of retinal specific promoters such as rhodopsin and IRBP cloned into pXCJL.1 are under construction. An update on developments in photoreceptor cell-directed expression of virally delivered genes will be presented.

  12. Gene therapy in animal models of autosomal dominant retinitis pigmentosa.

    PubMed

    Rossmiller, Brian; Mao, Haoyu; Lewin, Alfred S

    2012-01-01

    Gene therapy for dominantly inherited genetic disease is more difficult than gene-based therapy for recessive disorders, which can be treated with gene supplementation. Treatment of dominant disease may require gene supplementation partnered with suppression of the expression of the mutant gene either at the DNA level, by gene repair, or at the RNA level by RNA interference or transcriptional repression. In this review, we examine some of the gene delivery approaches used to treat animal models of autosomal dominant retinitis pigmentosa, focusing on those models associated with mutations in the gene for rhodopsin. We conclude that combinatorial approaches have the greatest promise for success.

  13. Gene therapy in animal models of autosomal dominant retinitis pigmentosa

    PubMed Central

    Rossmiller, Brian; Mao, Haoyu

    2012-01-01

    Gene therapy for dominantly inherited genetic disease is more difficult than gene-based therapy for recessive disorders, which can be treated with gene supplementation. Treatment of dominant disease may require gene supplementation partnered with suppression of the expression of the mutant gene either at the DNA level, by gene repair, or at the RNA level by RNA interference or transcriptional repression. In this review, we examine some of the gene delivery approaches used to treat animal models of autosomal dominant retinitis pigmentosa, focusing on those models associated with mutations in the gene for rhodopsin. We conclude that combinatorial approaches have the greatest promise for success. PMID:23077406

  14. Non-syndromic retinal ciliopathies: translating gene discovery into therapy.

    PubMed

    Estrada-Cuzcano, Alejandro; Roepman, Ronald; Cremers, Frans P M; den Hollander, Anneke I; Mans, Dorus A

    2012-10-15

    Homozygosity mapping and exome sequencing have accelerated the discovery of gene mutations and modifier alleles implicated in inherited retinal degeneration in humans. To date, 158 genes have been found to be mutated in individuals with retinal dystrophies. Approximately one-third of the gene defects underlying retinal degeneration affect the structure and/or function of the 'connecting cilium' in photoreceptors. This structure corresponds to the transition zone of a prototypic cilium, a region with increasing relevance for ciliary homeostasis. The connecting cilium connects the inner and outer segments of the photoreceptor, mediating bi-directional transport of phototransducing proteins required for vision. In fact, the outer segment, connecting cilium and associated basal body, forms a highly specialized sensory cilium, fully dedicated to photoreception and subsequent signal transduction to the brain. At least 21 genes that encode ciliary proteins are implicated in non-syndromic retinal dystrophies such as cone dystrophy, cone-rod dystrophy, Leber congenital amaurosis (LCA), macular degeneration or retinitis pigmentosa (RP). The generation and characterization of vertebrate retinal ciliopathy animal models have revealed insights into the molecular disease mechanism which are indispensable for the development and evaluation of therapeutic strategies. Gene augmentation therapy has proven to be safe and successful in restoring long-term sight in mice, dogs and humans suffering from LCA or RP. Here, we present a comprehensive overview of the genes, mutations and modifier alleles involved in non-syndromic retinal ciliopathies, review the progress in dissecting the associated retinal disease mechanisms and evaluate gene augmentation approaches to antagonize retinal degeneration in these ciliopathies.

  15. Gene Therapy Approaches For The Treatment Of Retinal Disorders

    PubMed Central

    Petit, Lolita; Punzo, Claudio

    2016-01-01

    There is an impelling need to develop effective therapeutic strategies for patients with retinal disorders. Gleaning from the large quantity of information gathered over the past two decades on the mechanisms governing degeneration of the retina, it is now possible to devise innovative therapies based on retinal gene transfer. Different gene-based approaches are under active investigation. They include strategies to correct the specific genetic defect in inherited retinal diseases, strategies to delay the onset of blindness independently of the disease-causing mutations and strategies to reactivate residual cells at late stages of the diseases. In this review, we discuss the status of application of these technologies, outlining the future therapeutic potential for many forms of retinal blinding diseases. PMID:27875674

  16. Correction of Monogenic and Common Retinal Disorders with Gene Therapy.

    PubMed

    Sengillo, Jesse D; Justus, Sally; Cabral, Thiago; Tsang, Stephen H

    2017-01-27

    The past decade has seen major advances in gene-based therapies, many of which show promise for translation to human disease. At the forefront of research in this field is ocular disease, as the eye lends itself to gene-based interventions due to its accessibility, relatively immune-privileged status, and ability to be non-invasively monitored. A landmark study in 2001 demonstrating successful gene therapy in a large-animal model for Leber congenital amaurosis set the stage for translation of these strategies from the bench to the bedside. Multiple clinical trials have since initiated for various retinal diseases, and further improvements in gene therapy techniques have engendered optimism for alleviating inherited blinding disorders. This article provides an overview of gene-based strategies for retinal disease, current clinical trials that engage these strategies, and the latest techniques in genome engineering, which could serve as the next frontline of therapeutic interventions.

  17. Correction of Monogenic and Common Retinal Disorders with Gene Therapy

    PubMed Central

    Sengillo, Jesse D.; Justus, Sally; Cabral, Thiago; Tsang, Stephen H.

    2017-01-01

    The past decade has seen major advances in gene-based therapies, many of which show promise for translation to human disease. At the forefront of research in this field is ocular disease, as the eye lends itself to gene-based interventions due to its accessibility, relatively immune-privileged status, and ability to be non-invasively monitored. A landmark study in 2001 demonstrating successful gene therapy in a large-animal model for Leber congenital amaurosis set the stage for translation of these strategies from the bench to the bedside. Multiple clinical trials have since initiated for various retinal diseases, and further improvements in gene therapy techniques have engendered optimism for alleviating inherited blinding disorders. This article provides an overview of gene-based strategies for retinal disease, current clinical trials that engage these strategies, and the latest techniques in genome engineering, which could serve as the next frontline of therapeutic interventions. PMID:28134823

  18. Gene Therapy in the Retinal Degeneration Slow Model of Retinitis Pigmentosa

    PubMed Central

    Cai, Xue; Conley, Shannon M.; Naash, Muna I.

    2011-01-01

    Human blinding disorders are often initiated by hereditary mutations that insult rod and/or cone photoreceptors and cause subsequent cellular death. Generally, the disease phenotype can be predicted from the specific mutation as many photoreceptor genes are specific to rods or cones; however certain genes, such as Retinal Degeneration Slow (RDS), are expressed in both cell types and cause different forms of retinal disease affecting rods, cones, or both photoreceptors. RDS is a transmembrane glycoprotein critical for photoreceptor outer segment disc morphogenesis, structural maintenance, and renewal. Studies using animal models with Rds mutations provide valuable insight into Rds gene function and regulation; and a better understanding of the physiology, pathology, and underlying degenerative mechanisms of inherited retinal disease. Furthermore, these models are an excellent tool in the process of developing therapeutic interventions for the treatment of inherited retinal degenerations. In this paper, we review these topics with particular focus on the use of rds models in gene therapy. PMID:20238065

  19. [Specific gene therapy for hereditary retinal dystrophies - an update].

    PubMed

    Stieger, K; Lorenz, B

    2014-03-01

    Treatment possibilities based on specific gene therapy strategies have become reality for a small number of patients with hereditary retinal dystrophies and are currently under investigation in several clinical trials worldwide. The most advanced studies are for patients suffering from mutations in the RPE65 gene. In addition, studies are ongoing for patients with disease causing mutations in the MERTK, REP1, ABCA4, or Myosin7A gene. Depending on the size of the gene copy to be transferred, two vectors are currently used in clinical trials: vectors based on adeno-associated virus (AAV) or on lentivirus (equine infectious anaemia virus, EIAV). An important aspect of current research includes the capacity to objectively measure the treatment effect in patients, since this is currently limited. This article gives an overview of the current state of specific gene therapy for hereditary retinal dystrophies. Georg Thieme Verlag KG Stuttgart · New York.

  20. Nanoparticle-based Technologies for Retinal Gene Therapy

    PubMed Central

    Adijanto, Jeffrey; Naash, Muna I

    2015-01-01

    For patients with hereditary retinal diseases, retinal gene therapy offers significant promise for the prevention of retinal degeneration. While adeno-associated virus (AAV)-based systems remain the most popular gene delivery method due to their high efficiency and successful clinical results, other delivery systems, such as non-viral nanoparticles (NPs) are being developed as additional therapeutic options. NP technologies come in several categories (e.g., polymer, liposomes, peptide compacted DNA), several of which have been tested in mouse models of retinal disease. Here, we discuss the key biochemical features of the different NPs that influence how they are internalized into cells, escape from endosomes, and are delivered into the nucleus. We review the primary mechanism of NP uptake by retinal cells and highlight various NPs that have been successfully used for in vivo gene delivery to the retina and RPE. Finally, we consider the various strategies that can be implemented in the plasmid DNA to generate persistent, high levels of gene expression. PMID:25592325

  1. Novel adeno-associated viral vectors for retinal gene therapy.

    PubMed

    Vandenberghe, L H; Auricchio, A

    2012-02-01

    Vectors derived from adeno-associated virus (AAV) are currently the most promising vehicles for therapeutic gene delivery to the retina. Recently, subretinal administration of AAV2 has been demonstrated to be safe and effective in patients with a rare form of inherited childhood blindness, suggesting that AAV-mediated retinal gene therapy may be successfully extended to other blinding conditions. This is further supported by the great versatility of AAV as a vector platform as there are a large number of AAV variants and many of these have unique transduction characteristics useful for targeting different cell types in the retina including glia, epithelium and many types of neurons. Naturally occurring, rationally designed or in vitro evolved AAV vectors are currently being utilized to transduce several different cell types in the retina and to treat a variety of animal models of retinal disease. The continuous and creative development of AAV vectors provides opportunities to overcome existing challenges in retinal gene therapy such as efficient transfer of genes exceeding AAV's cargo capacity, or the targeting of specific cells within the retina or transduction of photoreceptors following routinely used intravitreal injections. Such developments should ultimately advance the treatment of a wide range of blinding retinal conditions.

  2. Angiogenic gene therapy does not cause retinal pathology.

    PubMed

    Prokosch, Verena; Stupp, Tobias; Spaniol, Kristina; Pham, Emmanuel; Nikol, Sigrid

    2014-01-01

    The potential negative influence of angiogenic gene therapy on the development or progression of retinal pathologies such as diabetic retinopathy (DR) or age-related macular degeneration (AMD) has led to the systematic exclusion of affected patients from trials. We investigated the role of nonviral fibroblast factor 1 (NV1FGF) in two phase II, multinational, double-blind, randomized, placebo-controlled, gene therapy trials (TALISMAN 201 and 211). One hundred and fifty-two subjects with critical limb ischemia or claudication were randomized to receive eight intramuscular injections of 2.5 ml of NV1FGF at 0.2 mg/ml or 0.4 mg/dl or placebo. One hundred and fifty-two patients received a plasmid dose of NV1FGF of up to 32 mg or placebo. All patients underwent a systematic ophthalmologic examination at baseline and at 3, 6 or 12 months following gene therapy. Twenty-six of these patients (Münster subgroup) received a retinal fluorescence angiography at baseline and at final examination. Among those 26 patients, four of nine patients with diabetes suffered from nonproliferative DR. Three patients showed non-exsudative AMD. No change of retinal morphology or function was observed in Münster subgroup of both TALISMAN trials independent of the intramuscular NV1FGF dosage applied. Angiogenic gene therapy using NV1FGF is safe even in diabetics. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Gene therapy of inherited retinal degenerations: prospects and challenges.

    PubMed

    Trapani, Ivana; Banfi, Sandro; Simonelli, Francesca; Surace, Enrico M; Auricchio, Alberto

    2015-04-01

    Because of its favorable anatomical and immunological characteristics, the eye has been at the forefront of translational gene therapy. Dozens of promising proofs of concept have been obtained in animal models of inherited retinal degenerations (IRDs), and some of them have been relayed to the clinic. The results from the first clinical trials for a congenital form of blindness have generated great interest and have demonstrated the safety and efficacy of intraocular administrations of viral vectors in humans. However, this progress has also generated new questions and posed challenges that need to be addressed to further expand the applicability of gene therapy in the eye, including safe delivery of viral vectors to the outer retina, treatment of dominant IRDs as well as of IRDs caused by mutations in large genes, and, finally, selection of the appropriate IRDs and patients to maximize the efficacy of gene transfer. This review summarizes the strategies that are currently being exploited to overcome these challenges and drive the clinical development of retinal gene therapy.

  4. Prospects for retinal cone-targeted gene therapy.

    PubMed

    Alexander, John J; Hauswirth, William W

    2008-06-01

    Gene therapy strategies that target therapeutic genes to retinal cones are a worthy goal both because cone photoreceptor diseases are severely vision limiting and because many retinal diseases that do not affect cones directly eventually lead to cone loss, the reason for eventual blindness. Human achromatopsia is a genetic disease of cones that renders them nonfunctional but otherwise intact. Thus, animal models of achromatopsia were used in conjunction with adeno-associated virus (AAV) vectors whose serotype efficiently transduces cones and with a promoter that limits transgene expression to cones. In the Gnat2(cpfl3) mouse model of one genetic form of human achromatopsia, we were able to demonstrate recovery of normal cone function and visual acuity after a single subretinal treatment of vector that supplied wild-type Gnat2 protein to cones. This validates the overall strategy of targeting cones using recombinant viral vectors and justifies a more complete examination of animal models of cone disease as a prelude to considering a clinical gene therapy trial. Copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.

  5. Range of retinal diseases potentially treatable by AAV-vectored gene therapy.

    PubMed

    Hauswirth, William W; Li, Quihong; Raisler, Brian; Timmers, Adrian M; Berns, Kenneth I; Flannery, John G; LaVail, Matthew M; Lewin, Alfred S

    2004-01-01

    Viable strategies for retinal gene therapy must be designed to cope with the genetic nature of the disease and/or the primary pathologic process responsible for retinal malfunction. For dominant gene defects the aim must be to destroy the presumably toxic gene product, for recessive gene defects the direct approach aims to provide a wild-type copy of the gene to the affected retinal cell type, and for diseases of either complex or unknown genetic origin, more general cell survival strategies that deal with preserving affected retinal cells are often the best and only option. Hence examples of each type of therapy will be briefly discussed in several animal models, including ribozyme therapy for autosomal dominant retinitis pigmentosa in the transgenic P23H opsin rat, beta-PDE gene augmentation therapy for autosomal recessive retinitis pigmentosa in the rd mouse, glial cell-derived neurotrophic factor (GDNF) gene therapy for autosomal dominant RP in the transgenic S334ter opsin rat and pigment epithelial cell-derived neurotrophic factor (PEDF) gene therapy for neovascular retinal disease in rodents. Each employs a recombinant AAV vectored passenger gene controlled by one of several promoters supporting either photoreceptor-specific expression or more general retinal cell expression depending on the therapeutic requirements.

  6. Gene therapy for retinal ganglion cell neuroprotection in glaucoma.

    PubMed

    Wilson, A M; Di Polo, A

    2012-02-01

    Glaucoma is the leading cause of irreversible blindness worldwide. The primary cause of glaucoma is not known, but several risk factors have been identified, including elevated intraocular pressure and age. Loss of vision in glaucoma is caused by the death of retinal ganglion cells (RGCs), the neurons that convey visual information from the retina to the brain. Therapeutic strategies aimed at delaying or halting RGC loss, known as neuroprotection, would be valuable to save vision in glaucoma. In this review, we discuss the significant progress that has been made in the use of gene therapy to understand mechanisms underlying RGC degeneration and to promote the survival of these neurons in experimental models of optic nerve injury.

  7. [Progress in research on pathogenic genes and gene therapy for inherited retinal diseases].

    PubMed

    Zhu, Ling; Cao, Cong; Sun, Jiji; Gao, Tao; Liang, Xiaoyang; Nie, Zhipeng; Ji, Yanchun; Jiang, Pingping; Guan, Minxin

    2017-02-10

    Inherited retinal diseases (IRDs), including retinitis pigmentosa, Usher syndrome, Cone-Rod degenerations, inherited macular dystrophy, Leber's congenital amaurosis, Leber's hereditary optic neuropathy are the most common and severe types of hereditary ocular diseases. So far more than 200 pathogenic genes have been identified. With the growing knowledge of the genetics and mechanisms of IRDs, a number of gene therapeutic strategies have been developed in the laboratory or even entered clinical trials. Here the progress of IRD research on the pathogenic genes and therapeutic strategies, particularly gene therapy, are reviewed.

  8. AAV-mediated gene therapy in mouse models of recessive retinal degeneration

    PubMed Central

    Pang, Ji-jing; Lei, Lei; Dai, Xufeng; Shi, Wei; Liu, Xuan; Dinculescu, Astra; McDowell, J. Hugh

    2013-01-01

    In recent years, more and more mutant genes that cause retinal diseases have been detected. At the same time, many naturally occurring mouse models of retinal degeneration have also been found, which show similar changes to human retinal diseases. These, together with improved viral vector quality allow more and more traditionally incurable inherited retinal disorders to become potential candidates for gene therapy. Currently, the most common vehicle to deliver the therapeutic gene into target retinal cells is the adeno-associated viral vector (AAV). Following delivery to the immuno-priviledged subretinal space, AAV-vectors can efficiently target both retinal pigment epithelium and photoreceptor cells, the origin of most retinal degenerations. This review focuses on the AAV-based gene therapy in mouse models of recessive retinal degenerations, especially those in which delivery of the correct copy of the wild-type gene has led to significant beneficial effects on visual function, as determined by morphological, biochemical, electroretinographic and behavioral analysis. The past studies in animal models and ongoing successful LCA2 clinical trials, predict a bright future for AAV gene replacement treatment for inherited recessive retinal diseases. PMID:22300136

  9. Preclinical studies on specific gene therapy for recessive retinal degenerative diseases.

    PubMed

    Stieger, Knut; Chauveau, Christine; Rolling, Fabienne

    2010-10-01

    Inherited retinal diseases are non-lethal and have a wide level of genetic heterogeneity. Many of the genes involved have now been identified and their function elucidated, providing a major step towards the development of gene-based treatments. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV) because they mediate long-term transgene expression in a variety of retinal cell types and elicit minimal immune responses. Extensive preclinical evaluation of gene transfer strategies in small and large animal models is key to the development of successful gene-based therapies for the retina. These preclinical studies have already allowed the field to reach the point where gene therapy to treat inherited blindness has been brought to clinical trial. In this manuscript, we focus on recombinant AAV-mediated specific gene therapy for recessive retinal degenerative diseases we describe the preclinical studies for the treatment of retinal degeneration caused by retinal pigmented epithelium (RPE) cells or photoreceptor defects and the immune response induced by retinal rAAV gene transfer.

  10. AAV-mediated gene therapy for retinal disorders in large animal models.

    PubMed

    Stieger, Knut; Lhériteau, Elsa; Lhéariteau, Elsa; Moullier, Phillip; Rolling, Fabienne

    2009-01-01

    Retinal gene therapy holds great promise for the treatment of inherited and noninherited blinding diseases such as retinitis pigmentosa and age-related macular degeneration. The most widely used vectors for ocular gene delivery are based on adeno-associated virus (AAV) because they elicit minimal immune responses and mediated long-term transgene expression in a variety of retinal cell types. Extensive preclinical evaluation of new strategies in large animal models is key to the development of successful gene-based therapies for the retina. Because of differences in the retinal structures among species and unique structures such as the macula and fovea in the primate retina, nonhuman primates are widely used as preclinical animal models. But the observation of inherited retinal degenerations in dogs, which share a number of clinical and pathologic similarities with humans, has led to the characterization of several canine models for retinal diseases, one of which has already responded successfully to AAV-mediated gene therapy. This article presents a review and detailed discussion of the various large animal models available for the study of AAV-mediated gene-based therapies in the retina.

  11. Gene Therapy for Retinitis Pigmentosa Caused by MFRP Mutations: Human Phenotype and Preliminary Proof of Concept

    PubMed Central

    Dinculescu, Astra; Estreicher, Jackie; Zenteno, Juan C.; Aleman, Tomas S.; Schwartz, Sharon B.; Huang, Wei Chieh; Roman, Alejandro J.; Sumaroka, Alexander; Li, Qiuhong; Deng, Wen-Tao; Min, Seok-Hong; Chiodo, Vince A.; Neeley, Andy; Liu, Xuan; Shu, Xinhua; Matias-Florentino, Margarita; Buentello-Volante, Beatriz; Boye, Sanford L.; Cideciyan, Artur V.

    2011-01-01

    Abstract Autosomal recessive retinitis pigmentosa (RP), a heterogeneous group of degenerations of the retina, can be due to mutations in the MFRP (membrane-type frizzled-related protein) gene. A patient with RP with MFRP mutations, one of which is novel and the first splice site mutation reported, was characterized by noninvasive retinal and visual studies. The phenotype, albeit complex, suggested that this retinal degeneration may be a candidate for gene-based therapy. Proof-of-concept studies were performed in the rd6 Mfrp mutant mouse model. The fast-acting tyrosine-capsid mutant AAV8 (Y733F) vector containing the small chicken β-actin promoter driving the wild-type mouse Mfrp gene was used. Subretinal vector delivery on postnatal day 14 prevented retinal degeneration. Treatment rescued rod and cone photoreceptors, as assessed by electroretinography and retinal histology at 2 months of age. This AAV-mediated gene delivery also resulted in robust MFRP expression predominantly in its normal location within the retinal pigment epithelium apical membrane and its microvilli. The clinical features of MFRP-RP and our preliminary data indicating a response to gene therapy in the rd6 mouse suggest that this form of RP is a potential target for gene-based therapy. PMID:22142163

  12. Gene therapy for retinitis pigmentosa caused by MFRP mutations: human phenotype and preliminary proof of concept.

    PubMed

    Dinculescu, Astra; Estreicher, Jackie; Zenteno, Juan C; Aleman, Tomas S; Schwartz, Sharon B; Huang, Wei Chieh; Roman, Alejandro J; Sumaroka, Alexander; Li, Qiuhong; Deng, Wen-Tao; Min, Seok-Hong; Chiodo, Vince A; Neeley, Andy; Liu, Xuan; Shu, Xinhua; Matias-Florentino, Margarita; Buentello-Volante, Beatriz; Boye, Sanford L; Cideciyan, Artur V; Hauswirth, William W; Jacobson, Samuel G

    2012-04-01

    Autosomal recessive retinitis pigmentosa (RP), a heterogeneous group of degenerations of the retina, can be due to mutations in the MFRP (membrane-type frizzled-related protein) gene. A patient with RP with MFRP mutations, one of which is novel and the first splice site mutation reported, was characterized by noninvasive retinal and visual studies. The phenotype, albeit complex, suggested that this retinal degeneration may be a candidate for gene-based therapy. Proof-of-concept studies were performed in the rd6 Mfrp mutant mouse model. The fast-acting tyrosine-capsid mutant AAV8 (Y733F) vector containing the small chicken β-actin promoter driving the wild-type mouse Mfrp gene was used. Subretinal vector delivery on postnatal day 14 prevented retinal degeneration. Treatment rescued rod and cone photoreceptors, as assessed by electroretinography and retinal histology at 2 months of age. This AAV-mediated gene delivery also resulted in robust MFRP expression predominantly in its normal location within the retinal pigment epithelium apical membrane and its microvilli. The clinical features of MFRP-RP and our preliminary data indicating a response to gene therapy in the rd6 mouse suggest that this form of RP is a potential target for gene-based therapy.

  13. Dawn of ocular gene therapy: implications for molecular diagnosis in retinal disease.

    PubMed

    Zaneveld, Jacques; Wang, Feng; Wang, Xia; Chen, Rui

    2013-02-01

    Personalized medicine aims to utilize genomic information about patients to tailor treatment. Gene replacement therapy for rare genetic disorders is perhaps the most extreme form of personalized medicine, in that the patients' genome wholly determines their treatment regimen. Gene therapy for retinal disorders is poised to become a clinical reality. The eye is an optimal site for gene therapy due to the relative ease of precise vector delivery, immune system isolation, and availability for monitoring of any potential damage or side effects. Due to these advantages, clinical trials for gene therapy of retinal diseases are currently underway. A necessary precursor to such gene therapies is accurate molecular diagnosis of the mutation(s) underlying disease. In this review, we discuss the application of Next Generation Sequencing (NGS) to obtain such a diagnosis and identify disease causing genes, using retinal disorders as a case study. After reviewing ocular gene therapy, we discuss the application of NGS to the identification of novel Mendelian disease genes. We then compare current, array based mutation detection methods against next NGS-based methods in three retinal diseases: Leber's Congenital Amaurosis, Retinitis Pigmentosa, and Stargardt's disease. We conclude that next-generation sequencing based diagnosis offers several advantages over array based methods, including a higher rate of successful diagnosis and the ability to more deeply and efficiently assay a broad spectrum of mutations. However, the relative difficulty of interpreting sequence results and the development of standardized, reliable bioinformatic tools remain outstanding concerns. In this review, recent advances NGS based molecular diagnoses are discussed, as well as their implications for the development of personalized medicine.

  14. Dawn of ocular gene therapy: implications for molecular diagnosis in retinal disease

    PubMed Central

    Jacques, ZANEVELD; Feng, WANG; Xia, WANG; Rui, CHEN

    2013-01-01

    Personalized medicine aims to utilize genomic information about patients to tailor treatment. Gene replacement therapy for rare genetic disorders is perhaps the most extreme form of personalized medicine, in that the patients’ genome wholly determines their treatment regimen. Gene therapy for retinal disorders is poised to become a clinical reality. The eye is an optimal site for gene therapy due to the relative ease of precise vector delivery, immune system isolation, and availability for monitoring of any potential damage or side effects. Due to these advantages, clinical trials for gene therapy of retinal diseases are currently underway. A necessary precursor to such gene therapies is accurate molecular diagnosis of the mutation(s) underlying disease. In this review, we discuss the application of Next Generation Sequencing (NGS) to obtain such a diagnosis and identify disease causing genes, using retinal disorders as a case study. After reviewing ocular gene therapy, we discuss the application of NGS to the identification of novel Mendelian disease genes. We then compare current, array based mutation detection methods against next NGS-based methods in three retinal diseases: Leber’s Congenital Amaurosis, Retinitis Pigmentosa, and Stargardt’s disease. We conclude that next-generation sequencing based diagnosis offers several advantages over array based methods, including a higher rate of successful diagnosis and the ability to more deeply and efficiently assay a broad spectrum of mutations. However, the relative difficulty of interpreting sequence results and the development of standardized, reliable bioinformatic tools remain outstanding concerns. In this review, recent advances NGS based molecular diagnoses are discussed, as well as their implications for the development of personalized medicine. PMID:23393028

  15. Gene Therapy and Stem Cell Transplantation in Retinal Disease: The New Frontier.

    PubMed

    MacLaren, Robert E; Bennett, Jean; Schwartz, Steven D

    2016-10-01

    Gene and cell therapies have the potential to prevent, halt, or reverse diseases of the retina in patients with currently incurable blinding conditions. Over the past 2 decades, major advances in our understanding of the pathobiologic basis of retinal diseases, coupled with growth of gene transfer and cell transplantation biotechnologies, have created optimism that previously blinding retinal conditions may be treatable. It is now possible to deliver cloned genes safely and stably to specific retinal cell types in humans. Preliminary results testing gene augmentation strategies in human recessive diseases suggest promising safety and efficacy profiles, including improved visual function outcomes over extended periods. Additional gene-based strategies under development include approaches to autosomal dominant disease ("gain of function"), attempts to deliver genes encoding therapeutic proteins with proven mechanisms of action interfering with specific disease pathways, and approaches that could be used to render retinal cells other than atrophied photoreceptors light sensitive. In the programs that are the furthest along-pivotal regulatory safety and efficacy trials studying individuals with retinal degeneration resulting from RPE65 mutations-initial results reveal a robust safety profile and clinically significant improvements in visual function, thereby making this program a frontrunner for the first approved gene therapy product in the United States. Similar to gene therapy, progress in regenerative or stem cell-based transplantation strategies has been substantial. It is now possible to deliver safely stem cell-derived, terminally differentiated, biologically and genetically defined retinal pigment epithelium (RPE) to the diseased human eye. Although demonstration of clinical efficacy is still well behind the gene therapy field, multiple programs investigating regenerative strategies in RPE disease are beginning to enroll subjects, and initial results suggest

  16. Leber's congenital amaurosis and the role of gene therapy in congenital retinal disorders

    PubMed Central

    Sharif, Walid; Sharif, Zuhair

    2017-01-01

    Leber's congenital amaurosis (LCA) and recent gene therapy advancement for treating inherited retinopathies were extensive literature reviewed using MEDLINE, PubMed and EMBASE. Adeno-associated viral vectors were the most utilised vectors for ocular gene therapy. Cone photoreceptor cells might use an alternate pathway which was not reliant of the retinal pigment epithelium (RPE) derived retinoid isomerohydrolase (RPE65) to access the 11-cis retinal dehydechromophore. Research efforts dedicated on the progression of a gene-based therapy for the treatment of LCA2. Such gene therapy approaches were extremely successful in canine, porcine and rodent LCA2 models. The recombinant AAV2.hRPE65v2 adeno-associated vector contained the RPE65 cDNA and was replication deficient. Its in vitro injection in target cells induced RPE65 protein production. The gene therapy trials that were so far conducted for inherited retinopathies have generated promising results. Phase I clinical trials to cure LCA and choroideremia demonstrated that adeno-associated viral vectors containing RPE genes and photoreceptors respectively, could be successfully administered to inherited retinopathy patients. A phase III trial is presently ongoing and if successful, it will lead the way to additional gene therapy attempts to cure monogenic, inherited retinopathies. PMID:28393043

  17. Gene Therapy for the Retinal Degeneration of Usher Syndrome Caused by Mutations in MYO7A.

    PubMed

    Lopes, Vanda S; Williams, David S

    2015-01-20

    Usher syndrome is a deaf-blindness disorder. One of the subtypes, Usher 1B, is caused by loss of function of the gene encoding the unconventional myosin, MYO7A. A variety of different viral-based delivery approaches have been tested for retinal gene therapy to prevent the blindness of Usher 1B, and a clinical trial based on one of these approaches has begun. This review evaluates the different approaches.

  18. Non-Invasive Gene Transfer by Iontophoresis for Therapy of an Inherited Retinal Degeneration

    PubMed Central

    Souied, Eric H.; Reid, Silvia N. M.; Piri, Natik I.; Lerner, Leonid E.; Nusinowitz, Steven; Farber, Debora B.

    2009-01-01

    Despite extensive research on many of the genes responsible for inherited retinal degenerations leading to blindness, no effective treatment is currently available for patients affected with these diseases. Among the therapeutic approaches tested on animal models of human retinal degeneration, gene therapy using different types of viral vectors as delivery agents has yielded promising results. We report here our results on a non-invasive, non-viral delivery approach using transscleral iontophoresis for transfer of plasmid DNA into mouse retina. Proof of principle experiments were carried out using plasmid containing GFP cDNA to demonstrate expression of the transferred gene in the retina after single applications of iontophoresis. Various parameters for multiple applications of iontophoresis were optimized to sustain GFP gene expression in mouse photoreceptors. Subsequently, repeated iontophoresis of plasmid containing normal β-phosphodiesterase (β-PDE) cDNA was performed in the rd1 mouse, an animal model of autosomal recessive retinitis pigmentosa caused by a mutant β-PDE gene. In normal mice, transscleral iontophoresis of the GFP plasmid provided a significant increase in fluorescence of the retina in the treated versus non-treated eyes. In rd1 mice, repeated iontophoresis of β-PDE cDNA plasmid partially rescued photoreceptors morphologically, as observed by microscopy, and functionally, as recorded on ERG measurements, without adverse effects. Therefore, transscleral iontophoresis of plasmid DNA containing therapeutic genes may be an efficient, safe and non-invasive method for the treatment of retinal degenerations. PMID:18653181

  19. AAV-mediated Gene Therapy Halts Retinal Degeneration in PDE6β-deficient Dogs.

    PubMed

    Pichard, Virginie; Provost, Nathalie; Mendes-Madeira, Alexandra; Libeau, Lyse; Hulin, Philippe; Tshilenge, Kizito-Tshitoko; Biget, Marine; Ameline, Baptiste; Deschamps, Jack-Yves; Weber, Michel; Le Meur, Guylène; Colle, Marie-Anne; Moullier, Philippe; Rolling, Fabienne

    2016-05-01

    We previously reported that subretinal injection of AAV2/5 RK.cpde6β allowed long-term preservation of photoreceptor function and vision in the rod-cone dysplasia type 1 (rcd1) dog, a large animal model of naturally occurring PDE6β deficiency. The present study builds on these earlier findings to provide a detailed assessment of the long-term effects of gene therapy on the spatiotemporal pattern of retinal degeneration in rcd1 dogs treated at 20 days of age. We analyzed the density distribution of the retinal layers and of particular photoreceptor cells in 3.5-year-old treated and untreated rcd1 dogs. Whereas no rods were observed outside the bleb or in untreated eyes, gene transfer halted rod degeneration in all vector-exposed regions. Moreover, while gene therapy resulted in the preservation of cones, glial cells and both the inner nuclear and ganglion cell layers, no cells remained in vector-unexposed retinas, except in the visual streak. Finally, the retinal structure of treated 3.5-year-old rcd1 dogs was identical to that of unaffected 4-month-old rcd1 dogs, indicating near complete preservation. Our findings indicate that gene therapy arrests the degenerative process even if intervention is initiated after the onset of photoreceptor degeneration, and point to significant potential of this therapeutic approach in future clinical trials.

  20. RPE65: Role in the visual cycle, human retinal disease, and gene therapy

    PubMed Central

    Cai, Xue; Conley, Shannon M.; Naash, Muna I.

    2010-01-01

    RPE65 is an isomerohydrolase expressed in retinal pigment epithelium. It is critical for the regeneration of the visual pigment necessary for both rod and cone-mediated vision. Mutations in human RPE65 cause Leber’s congenital amaurosis and other forms of autosomal recessive retinitis pigmentosa which are associated with early-onset blindness. Several RPE65 animal models including two different mouse models and a naturally occurring canine model have been thoroughly characterized to determine the mechanisms that underlie RPE65 associated retinal dystrophies. More recently, substantial effort has gone into designing gene therapies for these diseases. Based on several encouraging reports from animal models, at least three clinical trials are currently underway for the treatment of LCA using modified AAV vectors carrying the RPE65 cDNA and have reported positive preliminary results. PMID:19373675

  1. RPE65: role in the visual cycle, human retinal disease, and gene therapy.

    PubMed

    Cai, Xue; Conley, Shannon M; Naash, Muna I

    2009-06-01

    RPE65 is an isomerohydrolase expressed in retinal pigment epithelium. It is critical for the regeneration of the visual pigment necessary for both rod and cone-mediated vision. Mutations in human RPE65 cause Leber's congenital amaurosis and other forms of autosomal recessive retinitis pigmentosa which are associated with early-onset blindness. Several RPE65 animal models including two different mouse models and a naturally occurring canine model have been thoroughly characterized to determine the mechanisms that underlie RPE65 associated retinal dystrophies. More recently, substantial effort has gone into designing gene therapies for these diseases. Based on several encouraging reports from animal models, at least three clinical trials are currently underway for the treatment of LCA using modified AAV vectors carrying the RPE65 cDNA and have reported positive preliminary results.

  2. Gene therapy for inherited retinal degenerations: initial successes and future challenges

    NASA Astrophysics Data System (ADS)

    Gupta, Priya R.; Huckfeldt, Rachel M.

    2017-10-01

    Inherited retinal degenerations are a clinically and genetically heterogeneous group of conditions that have historically shared an untreatable course. In recent years, however, a wide range of therapeutic strategies have demonstrated efficacy in preclinical studies and entered clinical trials with a common goal of improving visual function for patients affected with these conditions. Gene therapy offers a particularly elegant and precise opportunity to target the causative genetic mutations underlying these monogenic diseases. The present review will provide an overview of gene therapy with particular emphasis on key clinical results to date and challenges for the future.

  3. Personalized Medicine: Cell and Gene Therapy Based on Patient-Specific iPSC-Derived Retinal Pigment Epithelium Cells.

    PubMed

    Li, Yao; Chan, Lawrence; Nguyen, Huy V; Tsang, Stephen H

    2016-01-01

    Interest in generating human induced pluripotent stem (iPS) cells for stem cell modeling of diseases has overtaken that of patient-specific human embryonic stem cells due to the ethical, technical, and political concerns associated with the latter. In ophthalmology, researchers are currently using iPS cells to explore various applications, including: (1) modeling of retinal diseases using patient-specific iPS cells; (2) autologous transplantation of differentiated retinal cells that undergo gene correction at the iPS cell stage via gene editing tools (e.g., CRISPR/Cas9, TALENs and ZFNs); and (3) autologous transplantation of patient-specific iPS-derived retinal cells treated with gene therapy. In this review, we will discuss the uses of patient-specific iPS cells for differentiating into retinal pigment epithelium (RPE) cells, uncovering disease pathophysiology, and developing new treatments such as gene therapy and cell replacement therapy via autologous transplantation.

  4. Hypoxia-regulated retinal glial cell-specific promoter for potential gene therapy in disease.

    PubMed

    Prentice, Howard M; Biswal, Manas R; Dorey, C Kathleen; Blanks, Janet C

    2011-11-01

    Retinal Müller cells span the retina and secrete several trophic factors and represent the functional link between blood vessels and neurons, making them attractive targets for gene therapy. Therefore, a hypoxia-regulated, retinal glial cell-specific vector was constructed and tested for its response to hypoxia. A hybrid promoter containing domains of human glial fibrillary acidic protein (GFAP) and several hypoxia-responsive and aerobically silenced elements (HRSE) was incorporated separately into plasmid vectors for generation of self-complementary adeno-associated virus. Müller cells trasfected with plasmids or virus were compared with other cell lines using standard The mouse model of oxygen-induced retinopathy (OIR) was used to analyze retinas from mice exposed to high oxygen or room air to evaluate the induction of the regulated promoter. The regulated promoter was silenced under aerobic conditions in comparison with unregulated promoter in Müller cells. Hypoxia induced a 12-fold and 16-fold increase in promoter activity in primary Müller cells and human Müller cell lines, respectively. In the OIR model, intravitreal injection of the regulated promoter at postnatal day 7 (P7) resulted in high levels of green fluorescent protein expression only in retinal Müller cells at P17. GFP expression was absent in retinas of mice only exposed to room air. In vivo studies confirm normoxia silencing, hypoxic induction, and cell specificity of the regulated promoter in the mouse retina. This hypoxia-regulated, retinal glial cell-specific AAV vector provides a platform for gene therapy within regions of retinal hypoxia which are found in diabetic retinopathy and age-related macular degeneration.

  5. A long-term efficacy study of gene replacement therapy for RPGR-associated retinal degeneration

    PubMed Central

    Wu, Zhijian; Hiriyanna, Suja; Qian, Haohua; Mookherjee, Suddhasil; Campos, Maria M.; Gao, Chun; Fariss, Robert; Sieving, Paul A.; Li, Tiansen; Colosi, Peter; Swaroop, Anand

    2015-01-01

    Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene account for >70% of X-linked retinitis pigmentosa (XLRP) and 15–20% of all inherited retinal degeneration. Gene replacement therapy for RPGR-XLRP was hampered by the relatively slow disease progression in mouse models and by difficulties in cloning the full-length RPGR-ORF15 cDNA that includes a purine-rich 3′-coding region; however, its effectiveness has recently been demonstrated in four dogs with RPGR mutations. To advance the therapy to clinical stage, we generated new stable vectors in AAV8 or AAV9 carrying mouse and human full-length RPGR-ORF15-coding sequence and conducted a comprehensive long-term dose-efficacy study in Rpgr-knockout mice. After validating their ability to produce full-length proteins that localize to photoreceptor connecting cilia, we evaluated various vector doses in mice during a 2-year study. We demonstrate that eyes treated with a single injection of mouse or human RPGR-ORF15 vector at an optimal dose maintained the expression of RPGR-ORF15 throughout the study duration and exhibited higher electroretinogram amplitude, thicker photoreceptor layer and better targeting of opsins to outer segments compared with sham-treated eyes. Furthermore, mice that received treatment at an advanced age also showed remarkable preservation of retinal structure and function. Retinal toxicity was observed at high vector doses, highlighting the importance of careful dose optimization in future clinical experiments. Our long-term dose-efficacy study should facilitate the design of human trials with human RPGR-ORF15 vector as a clinical candidate. PMID:25877300

  6. Plasticity of the human visual system after retinal gene therapy in patients with Leber's congenital amaurosis.

    PubMed

    Ashtari, Manzar; Zhang, Hui; Cook, Philip A; Cyckowski, Laura L; Shindler, Kenneth S; Marshall, Kathleen A; Aravand, Puya; Vossough, Arastoo; Gee, James C; Maguire, Albert M; Baker, Chris I; Bennett, Jean

    2015-07-15

    Much of our knowledge of the mechanisms underlying plasticity in the visual cortex in response to visual impairment, vision restoration, and environmental interactions comes from animal studies. We evaluated human brain plasticity in a group of patients with Leber's congenital amaurosis (LCA), who regained vision through gene therapy. Using non-invasive multimodal neuroimaging methods, we demonstrated that reversing blindness with gene therapy promoted long-term structural plasticity in the visual pathways emanating from the treated retina of LCA patients. The data revealed improvements and normalization along the visual fibers corresponding to the site of retinal injection of the gene therapy vector carrying the therapeutic gene in the treated eye compared to the visual pathway for the untreated eye of LCA patients. After gene therapy, the primary visual pathways (for example, geniculostriate fibers) in the treated retina were similar to those of sighted control subjects, whereas the primary visual pathways of the untreated retina continued to deteriorate. Our results suggest that visual experience, enhanced by gene therapy, may be responsible for the reorganization and maturation of synaptic connectivity in the visual pathways of the treated eye in LCA patients. The interactions between the eye and the brain enabled improved and sustained long-term visual function in patients with LCA after gene therapy.

  7. Gene therapy rescues photoreceptor blindness in dogs and paves the way for treating human X-linked retinitis pigmentosa.

    PubMed

    Beltran, William A; Cideciyan, Artur V; Lewin, Alfred S; Iwabe, Simone; Khanna, Hemant; Sumaroka, Alexander; Chiodo, Vince A; Fajardo, Diego S; Román, Alejandro J; Deng, Wen-Tao; Swider, Malgorzata; Alemán, Tomas S; Boye, Sanford L; Genini, Sem; Swaroop, Anand; Hauswirth, William W; Jacobson, Samuel G; Aguirre, Gustavo D

    2012-02-07

    Hereditary retinal blindness is caused by mutations in genes expressed in photoreceptors or retinal pigment epithelium. Gene therapy in mouse and dog models of a primary retinal pigment epithelium disease has already been translated to human clinical trials with encouraging results. Treatment for common primary photoreceptor blindness, however, has not yet moved from proof of concept to the clinic. We evaluated gene augmentation therapy in two blinding canine photoreceptor diseases that model the common X-linked form of retinitis pigmentosa caused by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene, which encodes a photoreceptor ciliary protein, and provide evidence that the therapy is effective. After subretinal injections of adeno-associated virus-2/5-vectored human RPGR with human IRBP or GRK1 promoters, in vivo imaging showed preserved photoreceptor nuclei and inner/outer segments that were limited to treated areas. Both rod and cone photoreceptor function were greater in treated (three of four) than in control eyes. Histopathology indicated normal photoreceptor structure and reversal of opsin mislocalization in treated areas expressing human RPGR protein in rods and cones. Postreceptoral remodeling was also corrected: there was reversal of bipolar cell dendrite retraction evident with bipolar cell markers and preservation of outer plexiform layer thickness. Efficacy of gene therapy in these large animal models of X-linked retinitis pigmentosa provides a path for translation to human treatment.

  8. Assessment of different virus-mediated approaches for retinal gene therapy of Usher 1B.

    PubMed

    Lopes, Vanda S; Diemer, Tanja; Williams, David S

    2014-01-01

    Usher syndrome type 1B, which is characterized by congenital deafness and progressive retinal degeneration, is caused by the loss of the function of MYO7A. Prevention of the retinal degeneration should be possible by delivering functional MYO7A to retinal cells. Although this approach has been used successfully in clinical trials for Leber congenital amaurosis (LCA2), it remains a challenge for Usher 1B because of the large size of the MYO7A cDNA. Different viral vectors have been tested for use in MYO7A gene therapy. Here, we review approaches with lentiviruses, which can accommodate larger genes, as well as attempts to use adeno-associated virus (AAV), which has a smaller packaging capacity. In conclusion, both types of viral vector appear to be effective. Despite concerns about the ability of lentiviruses to access the photoreceptor cells, a phenotype of the photoreceptors of Myo7a-mutant mice can be corrected. And although MYO7A cDNA is significantly larger than the nominal carrying capacity of AAV, AAV-MYO7A in single vectors also corrected Myo7a-mutant phenotypes in photoreceptor and RPE cells. Interestingly, however, a dual AAV vector approach was found to be much less effective.

  9. Usher syndrome: animal models, retinal function of Usher proteins, and prospects for gene therapy

    PubMed Central

    Williams, David S.

    2009-01-01

    Usher syndrome is a deafness-blindness disorder. The blindness occurs from a progressive retinal degeneration that begins after deafness and after the retina has developed. Three clinical subtypes of Usher syndrome have been identified, with mutations in any one of six different genes giving rise to type 1, in any one of three different genes to type 2, and in one identified gene causing Usher type 3. Mutant mice for most of the genes have been studied; while they have clear inner ear defects, retinal phenotypes are relatively mild and have been difficult to characterize. The retinal functions of the Usher proteins are still largely unknown. Protein binding studies have suggested many interactions among the proteins, and a model of interaction among all the proteins in the photoreceptor synapse has been proposed. However this model is not supported by localization data from some laboratories, or the indication of any synaptic phenotype in mutant mice. An earlier suggestion, based on patient pathologies, of Usher protein function in the photoreceptor cilium continues to gain support from immunolocalization and mutant mouse studies, which are consistent with Usher protein interaction in the photoreceptor ciliary/periciliary region. So far, the most characterized Usher protein is myosin VIIa. It is present in the apical RPE and photoreceptor ciliary/periciliary region, where it is required for organelle transport and clearance of opsin from the connecting cilium, respectively. Usher syndrome is amenable to gene replacement therapy, but also has some specific challenges. Progress in this treatment approach has been achieved by correction of mutant phenotypes in Myo7a-null mouse retinas, following lentiviral delivery of MYO7A. PMID:17936325

  10. Modern retinal laser therapy

    PubMed Central

    Kozak, Igor; Luttrull, Jeffrey K.

    2014-01-01

    Medicinal lasers are a standard source of light to produce retinal tissue photocoagulation to treat retinovascular disease. The Diabetic Retinopathy Study and the Early Treatment Diabetic Retinopathy Study were large randomized clinical trials that have shown beneficial effect of retinal laser photocoagulation in diabetic retinopathy and have dictated the standard of care for decades. However, current treatment protocols undergo modifications. Types of lasers used in treatment of retinal diseases include argon, diode, dye and multicolor lasers, micropulse lasers and lasers for photodynamic therapy. Delivery systems include contact lens slit-lamp laser delivery, indirect ophthalmocope based laser photocoagulation and camera based navigated retinal photocoagulation with retinal eye-tracking. Selective targeted photocoagulation could be a future alternative to panretinal photocoagulation. PMID:25892934

  11. Lighting a candle in the dark: advances in genetics and gene therapy of recessive retinal dystrophies.

    PubMed

    den Hollander, Anneke I; Black, Aaron; Bennett, Jean; Cremers, Frans P M

    2010-09-01

    Nonsyndromic recessive retinal dystrophies cause severe visual impairment due to the death of photoreceptor and retinal pigment epithelium cells. These diseases until recently have been considered to be incurable. Molecular genetic studies in the last two decades have revealed the underlying molecular causes in approximately two-thirds of patients. The mammalian eye has been at the forefront of therapeutic trials based on gene augmentation in humans with an early-onset nonsyndromic recessive retinal dystrophy due to mutations in the retinal pigment epithelium-specific protein 65kDa (RPE65) gene. Tremendous challenges still lie ahead to extrapolate these studies to other retinal disease-causing genes, as human gene augmentation studies require testing in animal models for each individual gene and sufficiently large patient cohorts for clinical trials remain to be identified through cost-effective mutation screening protocols.

  12. Lighting a candle in the dark: advances in genetics and gene therapy of recessive retinal dystrophies

    PubMed Central

    den Hollander, Anneke I.; Black, Aaron; Bennett, Jean; Cremers, Frans P.M.

    2010-01-01

    Nonsyndromic recessive retinal dystrophies cause severe visual impairment due to the death of photoreceptor and retinal pigment epithelium cells. These diseases until recently have been considered to be incurable. Molecular genetic studies in the last two decades have revealed the underlying molecular causes in approximately two-thirds of patients. The mammalian eye has been at the forefront of therapeutic trials based on gene augmentation in humans with an early-onset nonsyndromic recessive retinal dystrophy due to mutations in the retinal pigment epithelium–specific protein 65kDa (RPE65) gene. Tremendous challenges still lie ahead to extrapolate these studies to other retinal disease–causing genes, as human gene augmentation studies require testing in animal models for each individual gene and sufficiently large patient cohorts for clinical trials remain to be identified through cost-effective mutation screening protocols. PMID:20811160

  13. A review of therapeutic prospects of non-viral gene therapy in the retinal pigment epithelium

    PubMed Central

    Koirala, Adarsha; Conley, Shannon M.; Naash, Muna I.

    2013-01-01

    Ocular gene therapy has been extensively explored in recent years as a therapeutic avenue to target diseases of the cornea, retina and retinal pigment epithelium (RPE). Adeno-associated virus (AAV)-mediated gene therapy has shown promise in several RPE clinical trials but AAVs have limited payload capacity and potential immunogenicity. Traditionally however, non-viral alternatives have been plagued by low transfection efficiency, short-term expression and low expression levels. Recently, these drawbacks have begun to be overcome by the use of specialty carriers such as polylysine, liposomes, or polyethyleneimines, and by inclusion of suitable DNA elements to enhance gene expression and longevity. Recent advancements in the field have yielded non-viral vectors that have favorable safety profiles, lack immunogenicity, exhibit long-term elevated gene expression, and show efficient transfection in the retina and RPE, making them poised to transition to clinical applications. Here we discuss the advancements in nanotechnology and vector engineering that have improved the prospects for clinical application of non-viral gene therapy in the RPE. PMID:23796578

  14. Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease

    PubMed Central

    Beltran, William A.; Cideciyan, Artur V.; Iwabe, Simone; Swider, Malgorzata; Kosyk, Mychajlo S.; McDaid, Kendra; Martynyuk, Inna; Ying, Gui-Shuang; Shaffer, James; Deng, Wen-Tao; Boye, Sanford L.; Lewin, Alfred S.; Hauswirth, William W.; Jacobson, Samuel G.; Aguirre, Gustavo D.

    2015-01-01

    Inherited retinal degenerations cause progressive loss of photoreceptor neurons with eventual blindness. Corrective or neuroprotective gene therapies under development could be delivered at a predegeneration stage to prevent the onset of disease, as well as at intermediate-degeneration stages to slow the rate of progression. Most preclinical gene therapy successes to date have been as predegeneration interventions. In many animal models, as well as in human studies, to date, retinal gene therapy administered well after the onset of degeneration was not able to modify the rate of progression even when successfully reversing dysfunction. We evaluated consequences of gene therapy delivered at intermediate stages of disease in a canine model of X-linked retinitis pigmentosa (XLRP) caused by a mutation in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene. Spatiotemporal natural history of disease was defined and therapeutic dose selected based on predegeneration results. Then interventions were timed at earlier and later phases of intermediate-stage disease, and photoreceptor degeneration monitored with noninvasive imaging, electrophysiological function, and visual behavior for more than 2 y. All parameters showed substantial and significant arrest of the progressive time course of disease with treatment, which resulted in long-term improved retinal function and visual behavior compared with control eyes. Histology confirmed that the human RPGR transgene was stably expressed in photoreceptors and associated with improved structural preservation of rods, cones, and ON bipolar cells together with correction of opsin mislocalization. These findings in a clinically relevant large animal model demonstrate the long-term efficacy of RPGR gene augmentation and substantially broaden the therapeutic window for intervention in patients with RPGR-XLRP. PMID:26460017

  15. Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease.

    PubMed

    Beltran, William A; Cideciyan, Artur V; Iwabe, Simone; Swider, Malgorzata; Kosyk, Mychajlo S; McDaid, Kendra; Martynyuk, Inna; Ying, Gui-Shuang; Shaffer, James; Deng, Wen-Tao; Boye, Sanford L; Lewin, Alfred S; Hauswirth, William W; Jacobson, Samuel G; Aguirre, Gustavo D

    2015-10-27

    Inherited retinal degenerations cause progressive loss of photoreceptor neurons with eventual blindness. Corrective or neuroprotective gene therapies under development could be delivered at a predegeneration stage to prevent the onset of disease, as well as at intermediate-degeneration stages to slow the rate of progression. Most preclinical gene therapy successes to date have been as predegeneration interventions. In many animal models, as well as in human studies, to date, retinal gene therapy administered well after the onset of degeneration was not able to modify the rate of progression even when successfully reversing dysfunction. We evaluated consequences of gene therapy delivered at intermediate stages of disease in a canine model of X-linked retinitis pigmentosa (XLRP) caused by a mutation in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene. Spatiotemporal natural history of disease was defined and therapeutic dose selected based on predegeneration results. Then interventions were timed at earlier and later phases of intermediate-stage disease, and photoreceptor degeneration monitored with noninvasive imaging, electrophysiological function, and visual behavior for more than 2 y. All parameters showed substantial and significant arrest of the progressive time course of disease with treatment, which resulted in long-term improved retinal function and visual behavior compared with control eyes. Histology confirmed that the human RPGR transgene was stably expressed in photoreceptors and associated with improved structural preservation of rods, cones, and ON bipolar cells together with correction of opsin mislocalization. These findings in a clinically relevant large animal model demonstrate the long-term efficacy of RPGR gene augmentation and substantially broaden the therapeutic window for intervention in patients with RPGR-XLRP.

  16. Therapy for acute retinal necrosis.

    PubMed

    Kawaguchi, Tatsushi; Spencer, Doran B; Mochizuki, Manabu

    2008-01-01

    Acute retinal necrosis is a progressive necrotizing retinopathy caused by herpes simplex virus (HSV) or varicella zoster virus (VZV). The mainstay of its treatment is antiviral therapy against these pathogenic organisms, such as intravenous acyclovir or oral valacyclovir. Systemic and topical corticosteroids together with antiviral therapy are used as an anti-inflammatory treatment to minimize damages to the optic nerve and retinal blood vessels. Because the majority of severe cases of the disease show occlusive retinal vasculitis, a low dosage of aspirin is used as anti-thrombotic treatment. Vitreo-retinal surgery is useful to repair rhegmatogenous retinal detachment, one of the main late-stage complications. Moreover, recent articles have reported some encouraging results of prophylactic vitrectomy before rhegmatogenous retinal detachment occurs. The efficacy of laser photocoagulation to prevent the development or extension of rhegmatogenous retinal detachment is controversial. Despite these treatments, the visual prognosis of acute retinal necrosis is still poor, in particular VZV-induced acute retinal necrosis.

  17. Retinal gene therapy with a large MYO7A cDNA using adeno-associated virus.

    PubMed

    Lopes, V S; Boye, S E; Louie, C M; Boye, S; Dyka, F; Chiodo, V; Fofo, H; Hauswirth, W W; Williams, D S

    2013-08-01

    Usher 1 patients are born profoundly deaf and then develop retinal degeneration. Thus they are readily identified before the onset of retinal degeneration, making gene therapy a viable strategy to prevent their blindness. Here, we have investigated the use of adeno-associated viruses (AAVs) for the delivery of the Usher 1B gene, MYO7A, to retinal cells in cell culture and in Myo7a-null mice. MYO7A cDNA, under control of a smCBA promoter, was packaged in single AAV2 and AAV5 vectors and as two overlapping halves in dual AAV2 vectors. The 7.9-kb smCBA-MYO7A exceeds the capacity of an AAV vector; packaging of such oversized constructs into single AAV vectors may involve fragmentation of the gene. Nevertheless, the AAV2 and AAV5 single vector preparations successfully transduced photoreceptor and retinal pigment epithelium cells, resulting in functional, full-length MYO7A protein and correction of mutant phenotypes, suggesting successful homologous recombination of gene fragments. With discrete, conventional-sized dual AAV2 vectors, full-length MYO7A was detected, but the level of protein expression was variable, and only a minority of cells showed phenotype correction. Our results show that MYO7A therapy with AAV2 or AAV5 single vectors is efficacious; however, the dual AAV2 approach proved to be less effective.

  18. Retinal gene therapy in patients with choroideremia: initial findings from a phase 1/2 clinical trial.

    PubMed

    MacLaren, Robert E; Groppe, Markus; Barnard, Alun R; Cottriall, Charles L; Tolmachova, Tanya; Seymour, Len; Clark, K Reed; During, Matthew J; Cremers, Frans P M; Black, Graeme C M; Lotery, Andrew J; Downes, Susan M; Webster, Andrew R; Seabra, Miguel C

    2014-03-29

    Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1). We assessed the effects of retinal gene therapy with an adeno-associated viral (AAV) vector encoding REP1 (AAV.REP1) in patients with this disease. In a multicentre clinical trial, six male patients (aged 35-63 years) with choroideremia were administered AAV.REP1 (0·6-1·0×10(10) genome particles, subfoveal injection). Visual function tests included best corrected visual acuity, microperimetry, and retinal sensitivity tests for comparison of baseline values with 6 months after surgery. This study is registered with ClinicalTrials.gov, number NCT01461213. Despite undergoing retinal detachment, which normally reduces vision, two patients with advanced choroideremia who had low baseline best corrected visual acuity gained 21 letters and 11 letters (more than two and four lines of vision). Four other patients with near normal best corrected visual acuity at baseline recovered to within one to three letters. Mean gain in visual acuity overall was 3·8 letters (SE 4·1). Maximal sensitivity measured with dark-adapted microperimetry increased in the treated eyes from 23·0 dB (SE 1·1) at baseline to 25·3 dB (1·3) after treatment (increase 2·3 dB [95% CI 0·8-3·8]). In all patients, over the 6 months, the increase in retinal sensitivity in the treated eyes (mean 1·7 [SE 1·0]) was correlated with the vector dose administered per mm(2) of surviving retina (r=0·82, p=0·04). By contrast, small non-significant reductions (p>0·05) were noted in the control eyes in both maximal sensitivity (-0·8 dB [1·5]) and mean sensitivity (-1·6 dB [0·9]). One patient in whom the vector was not administered to the fovea re-established variable eccentric fixation that included the ectopic island of surviving retinal pigment epithelium that had been exposed to vector. The initial results of this retinal gene therapy trial are

  19. Hypotrichosis and juvenile macular dystrophy caused by CDH3 mutation: A candidate disease for retinal gene therapy

    PubMed Central

    Singh, Mandeep S.; Broadgate, Suzanne; Mathur, Ranjana; Holt, Richard; Halford, Stephanie; MacLaren, Robert E.

    2016-01-01

    Hypotrichosis with juvenile macular dystrophy (HJMD) is an autosomal recessive disorder that causes childhood visual impairment. HJMD is caused by mutations in CDH3 which encodes cadherin-3, a protein expressed in retinal pigment epithelium (RPE) cells that may have a key role in intercellular adhesion. We present a case of HJMD and analyse its phenotypic and molecular characteristics to assess the potential for retinal gene therapy as a means of preventing severe visual loss in this condition. Longitudinal in vivo imaging of the retina showed the relative anatomical preservation of the macula, which suggested the presence of a therapeutic window for gene augmentation therapy to preserve visual acuity. The coding sequence of CDH3 fits within the packaging limit of recombinant adeno-associated virus vectors that have been shown to be safe in clinical trials and can efficiently target RPE cells. This report expands the number of reported cases of HJMD and highlights the phenotypic characteristics to consider when selecting candidates for retinal gene therapy. PMID:27157923

  20. Low molecular weight oligochitosans for non-viral retinal gene therapy.

    PubMed

    Puras, G; Zarate, J; Aceves, M; Murua, A; Díaz, A R; Avilés-Triguero, M; Fernández, E; Pedraz, J L

    2013-02-01

    Ultrapure oligochitosans have recently been evaluated as a promising tool for corneal gene therapy; however, there are no reports regarding the potential use of this polymer in other ocular tissues. We have prepared and characterized at pH 7.1 oligochitosan/pCMS-EGFP polyplexes to evaluate the transfection efficiency in rat retinas after subretinal and intravitreal administration. Polyplexes were characterized in terms of shape, size, surface charge, DNA condensation, and transfection efficiency in HEK-293 and ARPE-19 culture cells. Polyplexes were positively charged, around 10 mV, and size oscillated between 256.5 ± 56 and 67.3 ± 0.44 nm, depending on the nitrogenous/phosphate ratio. Polyplexes efficiently protected the plasmid against enzymatic digestion. A drastic increase in transfection efficiency was observed when pH slightly decreased from 7.4 to 7.1 in both HEK-293 (from 19.1% to 51.5%) and ARPE-19 (from 2.0% to 36.5%) cells (data normalized to Lipofectamine™ 2000). In rat retinas, subretinal administrations transfected cells mainly in the RPE layer, whereas intravitreal injections transfected cells in the inner nuclear and plexiform layers of the retina and mainly in the ganglion cell layer. This study establishes the base for future treatments of genetic retinal disorders with low molecular weight oligochitosan polyplexes.

  1. AAV-Mediated Lysophosphatidylcholine Acyltransferase 1 (Lpcat1) Gene Replacement Therapy Rescues Retinal Degeneration in rd11 Mice

    PubMed Central

    Dai, Xufeng; Han, Juanjuan; Qi, Yan; Zhang, Hua; Xiang, Lue; Lv, Jineng; Li, Jie; Deng, Wen-Tao; Chang, Bo; Hauswirth, William W.; Pang, Ji-jing

    2014-01-01

    Purpose. The retinal degeneration 11 (rd11) mouse is a newly discovered, naturally occurring animal model with early photoreceptor dysfunction and rapid rod photoreceptor degeneration followed by cone degeneration. The rd11 mice carry a spontaneous mutation in the lysophosphatidylcholine acyltransferase 1 (Lpcat1) gene. Here, we evaluate whether gene replacement therapy using the fast-acting tyrosine-capsid mutant AAV8 (Y733F) can arrest retinal degeneration and restore retinal function in this model. Methods. The AAV8 (Y733F)-smCBA-Lpcat1 was delivered subretinally to postnatal day 14 (P14) rd11 mice in one eye only. At 10 weeks after injection, treated rd11 mice were examined by visually-guided behavior, electroretinography (ERG) and spectral domain optical coherence tomography (SD-OCT), and then killed for morphologic and biochemical examination. Results. Substantial scotopic and photopic ERG signals were maintained in treated rd11 eyes, whereas untreated eyes in the same animals showed extinguished signals. The SD-OCT (in vivo) and light microscopy (in vitro) showed a substantial preservation of the outer nuclear layer in most parts of the treated retina only. Almost wild-type LPCAT1 expression in photoreceptors with strong rod rhodopsin and M/S cone opsin staining, and normal visually-guided water maze behavioral performances were observed in treated rd11 mice. Conclusions. The results demonstrate that the tyrosine-capsid mutant AAV8 (Y733F) vector is effective for treating rapidly degenerating models of retinal degeneration and, moreover, is more therapeutically effective than AAV2 (Y444, 500, 730F) vector with the same promoter-cDNA payload. To our knowledge, this is the first demonstration of phenotypic rescue by gene therapy in an animal model of retinal degeneration caused by Lpcat1 mutation. PMID:24557352

  2. Retinal blinding disorders and gene therapy--molecular and clinical aspects.

    PubMed

    Lorenz, Birgit; Preising, Markus; Stieger, Knut

    2010-10-01

    Retinal blinding disorders together have a prevalence of 1 in 2000 humans world wide and represent a significant impact on the quality of life as well as the possibility to attain personal achievements. Mutations in genes that are expressed either in RPE cells, photoreceptors or bipolar cells can cause varying forms of degenerative or stationary retinal disorders, as the presence of the encoded proteins is crucial for normal function, maintenance and synaptic interaction. The degree of damage caused by different mutations depends upon the type of mutation within the gene, resulting in either total absence or the presence of a non-functional or potentially toxic protein. Potential treatment strategies require the identification of the cell type, in which the mutated gene is expressed for later targeting by viral vector mediated gene transfer. In the first part of this review, the authors present different cellular pathways that take place either in the RPE, photoreceptors, or bipolar cells. Furthermore, the authors demonstrate why genetic and molecular testing methods, which clearly identify the disease causing mutations, are crucial for attaining the correct diagnosis in order to identify patients suitable to be treated by upcoming new therapeutic methods. In the second part, a short clinical classification of the most important forms of retinal blinding disorders is given, together with clinical aspects concerning the problems that arise when facing low residual visual perception and the enormous heterogeneity of symptoms within these disorders.

  3. Plasticity of the human visual system after retinal gene therapy in patients with Leber’s congenital amaurosis

    PubMed Central

    Ashtari, Manzar; Zhang, Hui; Cook, Philip A.; Cyckowski, Laura L.; Shindler, Kenneth S.; Marshall, Kathleen A.; Aravand, Puya; Vossough, Arastoo; Gee, James C.; Maguire, Albert M.; Baker, Chris I.; Bennett, Jean

    2015-01-01

    Much of our knowledge of the mechanisms underlying plasticity in the visual cortex in response to visual impairment, vision restoration, and environmental interactions comes from animal studies. We evaluated human brain plasticity in a group of patients with Leber’s congenital amaurosis (LCA), who regained vision through gene therapy. Using non-invasive multimodal neuroimaging methods, we demonstrated that reversing blindness with gene therapy promoted long-term structural plasticity in the visual pathways emanating from the treated retina of LCA patients. The data revealed improvements and normalization along the visual fibers corresponding to the site of retinal injection of the gene therapy vector carrying the therapeutic gene in the treated eye compared to the visual pathway for the untreated eye of LCA patients. After gene therapy, the primary visual pathways (for example, geniculostriate fibers) in the treated retina were similar to those of sighted control subjects, whereas the primary visual pathways of the untreated retina continued to deteriorate. Our results suggest that visual experience, enhanced by gene therapy, may be responsible for the reorganization and maturation of synaptic connectivity in the visual pathways of the treated eye in LCA patients. The interactions between the eye and the brain enabled improved and sustained long-term visual function in patients with LCA after gene therapy. PMID:26180100

  4. Long-term rescue of cone photoreceptor degeneration in retinitis pigmentosa 2 (RP2)-knockout mice by gene replacement therapy.

    PubMed

    Mookherjee, Suddhasil; Hiriyanna, Suja; Kaneshiro, Kayleigh; Li, Linjing; Li, Yichao; Li, Wei; Qian, Haohua; Li, Tiansen; Khanna, Hemant; Colosi, Peter; Swaroop, Anand; Wu, Zhijian

    2015-11-15

    Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR or RP2 gene. With a goal to develop gene therapy for the XLRP-RP2 disease, we first performed detailed characterization of the Rp2-knockout (Rp2-KO) mice and observed early-onset cone dysfunction, which was followed by progressive cone degeneration, mimicking cone vision impairment in XLRP patients. The mice also exhibited distinct and significantly delayed falling phase of photopic b-wave of electroretinogram (ERG). Concurrently, we generated a self-complementary adeno-associated viral (AAV) vector carrying human RP2-coding sequence and demonstrated its ability to mediate stable RP2 protein expression in mouse photoreceptors. A long-term efficacy study was then conducted in Rp2-KO mice following AAV-RP2 vector administration. Preservation of cone function was achieved with a wide dose range over 18-month duration, as evidenced by photopic ERG and optomotor tests. The slower b-wave kinetics was also completely restored. Morphologically, the treatment preserved cone viability, corrected mis-trafficking of M-cone opsin and restored cone PDE6 expression. The therapeutic effect was achieved even in mice that received treatment at an advanced disease stage. The highest AAV-RP2 dose group demonstrated retinal toxicity, highlighting the importance of careful vector dosing in designing future human trials. The wide range of effective dose, a broad treatment window and long-lasting therapeutic effects should make the RP2 gene therapy attractive for clinical development. Published by Oxford University Press 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  5. Long-term rescue of cone photoreceptor degeneration in retinitis pigmentosa 2 (RP2)-knockout mice by gene replacement therapy

    PubMed Central

    Mookherjee, Suddhasil; Hiriyanna, Suja; Kaneshiro, Kayleigh; Li, Linjing; Li, Yichao; Li, Wei; Qian, Haohua; Li, Tiansen; Khanna, Hemant; Colosi, Peter; Swaroop, Anand; Wu, Zhijian

    2015-01-01

    Retinal neurodegenerative diseases are especially attractive targets for gene replacement therapy, which appears to be clinically effective for several monogenic diseases. X-linked forms of retinitis pigmentosa (XLRP) are relatively severe blinding disorders, resulting from progressive photoreceptor dysfunction primarily caused by mutations in RPGR or RP2 gene. With a goal to develop gene therapy for the XLRP-RP2 disease, we first performed detailed characterization of the Rp2-knockout (Rp2-KO) mice and observed early-onset cone dysfunction, which was followed by progressive cone degeneration, mimicking cone vision impairment in XLRP patients. The mice also exhibited distinct and significantly delayed falling phase of photopic b-wave of electroretinogram (ERG). Concurrently, we generated a self-complementary adeno-associated viral (AAV) vector carrying human RP2-coding sequence and demonstrated its ability to mediate stable RP2 protein expression in mouse photoreceptors. A long-term efficacy study was then conducted in Rp2-KO mice following AAV-RP2 vector administration. Preservation of cone function was achieved with a wide dose range over 18-month duration, as evidenced by photopic ERG and optomotor tests. The slower b-wave kinetics was also completely restored. Morphologically, the treatment preserved cone viability, corrected mis-trafficking of M-cone opsin and restored cone PDE6 expression. The therapeutic effect was achieved even in mice that received treatment at an advanced disease stage. The highest AAV-RP2 dose group demonstrated retinal toxicity, highlighting the importance of careful vector dosing in designing future human trials. The wide range of effective dose, a broad treatment window and long-lasting therapeutic effects should make the RP2 gene therapy attractive for clinical development. PMID:26358772

  6. Retinal morphology of patients with achromatopsia during early childhood: implications for gene therapy.

    PubMed

    Yang, Paul; Michaels, Keith V; Courtney, Robert J; Wen, Yuquan; Greninger, Daniel A; Reznick, Leah; Karr, Daniel J; Wilson, Lorri B; Weleber, Richard G; Pennesi, Mark E

    2014-07-01

    intervention. Neither age alone nor genotype alone predicts the degree of photoreceptor loss or preservation. Thus, in anticipation of future gene therapy trials in humans, we propose that handheld spectral-domain optical coherence tomography is an important tool for the early assessment and stratification of macular architecture in young children with achromatopsia.

  7. Gene therapy in the second eye of RPE65-deficient dogs improves retinal function

    PubMed Central

    Annear, MJ; Bartoe, JT; Barker, SE; Smith, AJ; Curran, PG; Bainbridge, JW; Ali, RR; Petersen-Jones, SM

    2012-01-01

    The purpose of this study was to evaluate whether immune responses interfered with gene therapy rescue using subretinally delivered recombinant adeno-associated viral vector serotype 2 carrying the RPE65 cDNA gene driven by the human RPE65 promoter (rAAV2.hRPE65p.hRPE65) in the second eye of RPE65−/− dogs that had previously been treated in a similar manner in the other eye. Bilateral subretinal injection was performed in nine dogs with the second eye treated 85–180 days after the first. Electroretinography (ERG) and vision testing showed rescue in 16 of 18 treated eyes, with no significant difference between first and second treated eyes. A serum neutralizing antibody (NAb) response to rAAV2 was detected in all treated animals, but this did not prevent or reduce the effectiveness of rescue in the second treated eye. We conclude that successful rescue using subretinal rAAV2.hRPE65p.hRPE65 gene therapy in the second eye is not precluded by prior gene therapy in the contralateral eye of the RPE65−/− dog. This finding has important implications for the treatment of human LCA type II patients. PMID:20703309

  8. Cell and gene therapy.

    PubMed

    Rao, Rajesh C; Zacks, David N

    2014-01-01

    Replacement or repair of a dysfunctional gene combined with promoting cell survival is a two-pronged approach that addresses an unmet need in the therapy of retinal degenerative diseases. In this chapter, we discuss various strategies toward achieving both goals: transplantation of wild-type cells to replace degenerating cells and to rescue gene function, sequential gene and cell therapy, and in vivo reprogramming of rods to cones. These approaches highlight cutting-edge advances in cell and gene therapy, and cellular lineage conversion in order to devise new therapies for various retinal degenerative diseases.

  9. Gene Augmentation Therapy Restores Retinal Function and Visual Behavior in a Sheep Model of CNGA3 Achromatopsia.

    PubMed

    Banin, Eyal; Gootwine, Elisha; Obolensky, Alexey; Ezra-Elia, Raaya; Ejzenberg, Ayala; Zelinger, Lina; Honig, Hen; Rosov, Alexander; Yamin, Esther; Sharon, Dror; Averbukh, Edward; Hauswirth, William W; Ofri, Ron

    2015-09-01

    Achromatopsia is a hereditary form of day blindness caused by cone photoreceptor dysfunction. Affected patients suffer from congenital color blindness, photosensitivity, and low visual acuity. Mutations in the CNGA3 gene are a major cause of achromatopsia, and a sheep model of this disease was recently characterized by our group. Here, we report that unilateral subretinal delivery of an adeno-associated virus serotype 5 (AAV5) vector carrying either the mouse or the human intact CNGA3 gene under the control of the red/green opsin promoter results in long-term recovery of visual function in CNGA3-mutant sheep. Treated animals demonstrated shorter maze passage times and a reduced number of collisions with obstacles compared with their pretreatment status, with values close to those of unaffected sheep. This effect was abolished when the treated eye was patched. Electroretinography (ERG) showed marked improvement in cone function. Retinal expression of the transfected human and mouse CNGA3 genes at the mRNA level was shown by polymerase chain reaction (PCR), and cone-specific expression of CNGA3 protein was demonstrated by immunohistochemisrty. The rescue effect has so far been maintained for over 3 years in the first-treated animals, with no obvious ocular or systemic side effects. The results support future application of subretinal AAV5-mediated gene-augmentation therapy in CNGA3 achromatopsia patients.

  10. Gene Augmentation Therapy Restores Retinal Function and Visual Behavior in a Sheep Model of CNGA3 Achromatopsia

    PubMed Central

    Banin, Eyal; Gootwine, Elisha; Obolensky, Alexey; Ezra-Elia, Raaya; Ejzenberg, Ayala; Zelinger, Lina; Honig, Hen; Rosov, Alexander; Yamin, Esther; Sharon, Dror; Averbukh, Edward; Hauswirth, William W; Ofri, Ron

    2015-01-01

    Achromatopsia is a hereditary form of day blindness caused by cone photoreceptor dysfunction. Affected patients suffer from congenital color blindness, photosensitivity, and low visual acuity. Mutations in the CNGA3 gene are a major cause of achromatopsia, and a sheep model of this disease was recently characterized by our group. Here, we report that unilateral subretinal delivery of an adeno-associated virus serotype 5 (AAV5) vector carrying either the mouse or the human intact CNGA3 gene under the control of the red/green opsin promoter results in long-term recovery of visual function in CNGA3-mutant sheep. Treated animals demonstrated shorter maze passage times and a reduced number of collisions with obstacles compared with their pretreatment status, with values close to those of unaffected sheep. This effect was abolished when the treated eye was patched. Electroretinography (ERG) showed marked improvement in cone function. Retinal expression of the transfected human and mouse CNGA3 genes at the mRNA level was shown by polymerase chain reaction (PCR), and cone-specific expression of CNGA3 protein was demonstrated by immunohistochemisrty. The rescue effect has so far been maintained for over 3 years in the first-treated animals, with no obvious ocular or systemic side effects. The results support future application of subretinal AAV5-mediated gene-augmentation therapy in CNGA3 achromatopsia patients. PMID:26087757

  11. CNTF Gene Therapy Confers Lifelong Neuroprotection in a Mouse Model of Human Retinitis Pigmentosa

    PubMed Central

    Lipinski, Daniel M; Barnard, Alun R; Singh, Mandeep S; Martin, Chris; Lee, Edward J; Davies, Wayne I L; MacLaren, Robert E

    2015-01-01

    The long-term outcome of neuroprotection as a therapeutic strategy for preventing cell death in neurodegenerative disorders remains unknown, primarily due to slow disease progression and the inherent difficulty of assessing neuronal survival in vivo. Employing a murine model of retinal disease, we demonstrate that ciliary neurotrophic factor (CNTF) confers life-long protection against photoreceptor degeneration. Repetitive retinal imaging allowed the survival of intrinsically fluorescent cone photoreceptors to be quantified in vivo. Imaging of the visual cortex and assessment of visually-evoked behavioral responses demonstrated that surviving cones retain function and signal correctly to the brain. The mechanisms underlying CNTF-mediated neuroprotection were explored through transcriptome analysis, revealing widespread upregulation of proteolysis inhibitors, which may prevent cellular/extracellular matrix degradation and complement activation in neurodegenerative diseases. These findings provide insights into potential novel therapeutic avenues for diseases such as retinitis pigmentosa and amyotrophic lateral sclerosis, for which CNTF has been evaluated unsuccessfully in clinical trials. PMID:25896245

  12. Cone specific promoter for use in gene therapy of retinal degenerative diseases.

    PubMed

    Dyka, Frank M; Boye, Sanford L; Ryals, Renee C; Chiodo, Vince A; Boye, Shannon E; Hauswirth, William W

    2014-01-01

    Achromatopsia (ACHM) is caused by a progressive loss of cone photoreceptors leading to color blindness and poor visual acuity. Animal studies and human clinical trials have shown that gene replacement therapy with adeno-associate virus (AAV) is a viable treatment option for this disease. Although there have been successful attempts to optimize capsid proteins for increased specificity, it is simpler to restrict expression via the use of cell type-specific promoters. To target cone photoreceptors, a chimeric promoter consisting of an enhancer element of interphotoreceptor retinoid-binding protein promoter and a minimal sequence of the human transducin alpha-subunit promoter (IRBPe/GNAT2) was created. Additionally, a synthetic transducin alpha-subunit promoter (synGNAT2/GNAT2) containing conserved sequence blocks located downstream of the transcriptional start was created. The strength and specificity of these promoters were evaluated in murine retina by immunohistochemistry. The results showed that the chimeric, (IRBPe/GNAT2) promoter is more efficient and specific than the synthetic, synGNAT2/GNAT2 promoter. Additionally, IRBPe/GNAT2-mediated expression was found in all cone subtypes and it was improved over existing promoters currently used for gene therapy of achromatopsia.

  13. Cone Specific Promoter for Use in Gene Therapy of Retinal Degenerative Diseases

    PubMed Central

    Dyka, Frank M.; Boye, Sanford L.; Ryals, Renee C.; Chiodo, Vince A.; Boye, Shannon E.; Hauswirth, William W.

    2015-01-01

    Achromatopsia (ACHM) is caused by a progressive loss of cone photoreceptors leading to color blindness and poor visual acuity. Animal studies and human clinical trials have shown that gene replacement therapy with adeno-associate virus (AAV) is a viable treatment option for this disease. Although there have been successful attempts to optimize capsid proteins for increased specificity, it is simpler to restrict expression via the use of cell type-specific promoters. To target cone photoreceptors, a chimeric promoter consisting of an enhancer element of inter-photoreceptor retinoid-binding protein promoter and a minimal sequence of the human transducin alpha-subunit promoter (IRBPe/GNAT2) was created. Additionally, a synthetic transducin alpha-subunit promoter (synGNAT2/GNAT2) containing conserved sequence blocks located downstream of the transcriptional start was created. The strength and specificity of these promoters were evaluated in murine retina by immunohistochemistry. The results showed that the chimeric, (IRBPe/GNAT2) promoter is more efficient and specific than the synthetic, synGNAT2/GNAT2 promoter. Additionally, IRBPe/GNAT2-mediated expression was found in all cone subtypes and it was improved over existing promoters currently used for gene therapy of achromatopsia. PMID:24664760

  14. Gene therapy with brain-derived neurotrophic factor as a protection: retinal ganglion cells in a rat glaucoma model.

    PubMed

    Martin, Keith R G; Quigley, Harry A; Zack, Donald J; Levkovitch-Verbin, Hana; Kielczewski, Jennifer; Valenta, Danielle; Baumrind, Lisa; Pease, Mary Ellen; Klein, Ronald L; Hauswirth, William W

    2003-10-01

    To develop a modified adenoassociated viral (AAV) vector capable of efficient transfection of retinal ganglion cells (RGCs) and to test the hypothesis that use of this vector to express brain-derived neurotrophic factor (BDNF) could be protective in experimental glaucoma. Ninety-three rats received one unilateral, intravitreal injection of either normal saline (n = 30), AAV-BDNF-woodchuck hepatitis posttranscriptional regulatory element (WPRE; n = 30), or AAV-green fluorescent protein (GFP)-WPRE (n = 33). Two weeks later, experimental glaucoma was induced in the injected eye by laser application to the trabecular meshwork. Survival of RGCs was estimated by counting axons in optic nerve cross sections after 4 weeks of glaucoma. Transgene expression was assessed by immunohistochemistry, Western blot analysis, and direct visualization of GFP. The density of GFP-positive cells in retinal wholemounts was 1,828 +/- 299 cells/mm(2) (72,273 +/- 11,814 cells/retina). Exposure to elevated intraocular pressure was similar in all groups. Four weeks after initial laser treatment, axon loss was 52.3% +/- 27.1% in the saline-treated group (n = 25) and 52.3% +/- 24.2% in the AAV-GFP-WPRE group (n = 30), but only 32.3% +/- 23.0% in the AAV-BDNF-WPRE group (n = 27). Survival in AAV-BDNF-WPRE animals increased markedly and the difference was significant compared with those receiving either AAV-GFP-WPRE (P = 0.002, t-test) or saline (P = 0.006, t-test). Overexpression of the BDNF gene protects RGC as estimated by axon counts in a rat glaucoma model, further supporting the potential feasibility of neurotrophic therapy as a complement to the lowering of IOP in the treatment of glaucoma.

  15. Antisense Oligonucleotide Therapy for Inherited Retinal Dystrophies.

    PubMed

    Gerard, Xavier; Garanto, Alejandro; Rozet, Jean-Michel; Collin, Rob W J

    2016-01-01

    Inherited retinal dystrophies (IRDs) are an extremely heterogeneous group of genetic diseases for which currently no effective treatment strategies exist. Over the last decade, significant progress has been made utilizing gene augmentation therapy for a few genetic subtypes of IRD, although several technical challenges so far prevent a broad clinical application of this approach for other forms of IRD. Many of the mutations leading to these retinal diseases affect pre-mRNA splicing of the mutated genes . Antisense oligonucleotide (AON)-mediated splice modulation appears to be a powerful approach to correct the consequences of such mutations at the pre-mRNA level , as demonstrated by promising results in clinical trials for several inherited disorders like Duchenne muscular dystrophy, hypercholesterolemia and various types of cancer. In this mini-review, we summarize ongoing pre-clinical research on AON-based therapy for a few genetic subtypes of IRD , speculate on other potential therapeutic targets, and discuss the opportunities and challenges that lie ahead to translate splice modulation therapy for retinal disorders to the clinic.

  16. Long-Term Gene Therapy Causes Transgene-Specific Changes in the Morphology of Regenerating Retinal Ganglion Cells

    PubMed Central

    Rodger, Jennifer; Drummond, Eleanor S.; Hellström, Mats; Robertson, Donald; Harvey, Alan R.

    2012-01-01

    Recombinant adeno-associated viral (rAAV) vectors can be used to introduce neurotrophic genes into injured CNS neurons, promoting survival and axonal regeneration. Gene therapy holds much promise for the treatment of neurotrauma and neurodegenerative diseases; however, neurotrophic factors are known to alter dendritic architecture, and thus we set out to determine whether such transgenes also change the morphology of transduced neurons. We compared changes in dendritic morphology of regenerating adult rat retinal ganglion cells (RGCs) after long-term transduction with rAAV2 encoding: (i) green fluorescent protein (GFP), or (ii) bi-cistronic vectors encoding GFP and ciliary neurotrophic factor (CNTF), brain-derived neurotrophic factor (BDNF) or growth-associated protein-43 (GAP43). To enhance regeneration, rats received an autologous peripheral nerve graft onto the cut optic nerve of each rAAV2 injected eye. After 5–8 months, RGCs with regenerated axons were retrogradely labeled with fluorogold (FG). Live retinal wholemounts were prepared and GFP positive (transduced) or GFP negative (non-transduced) RGCs injected iontophoretically with 2% lucifer yellow. Dendritic morphology was analyzed using Neurolucida software. Significant changes in dendritic architecture were found, in both transduced and non-transduced populations. Multivariate analysis revealed that transgenic BDNF increased dendritic field area whereas GAP43 increased dendritic complexity. CNTF decreased complexity but only in a subset of RGCs. Sholl analysis showed changes in dendritic branching in rAAV2-BDNF-GFP and rAAV2-CNTF-GFP groups and the proportion of FG positive RGCs with aberrant morphology tripled in these groups compared to controls. RGCs in all transgene groups displayed abnormal stratification. Thus in addition to promoting cell survival and axonal regeneration, vector-mediated expression of neurotrophic factors has measurable, gene-specific effects on the morphology of injured adult

  17. Retinitis Pigmentosa: Genes and Disease Mechanisms

    PubMed Central

    Ferrari, Stefano; Di Iorio, Enzo; Barbaro, Vanessa; Ponzin, Diego; Sorrentino, Francesco S; Parmeggiani, Francesco

    2011-01-01

    Retinitis pigmentosa (RP) is a group of inherited disorders affecting 1 in 3000-7000 people and characterized by abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium of the retina which lead to progressive visual loss. RP can be inherited in an autosomal dominant, autosomal recessive or X-linked manner. While usually limited to the eye, RP may also occur as part of a syndrome as in the Usher syndrome and Bardet-Biedl syndrome. Over 40 genes have been associated with RP so far, with the majority of them expressed in either the photoreceptors or the retinal pigment epithelium. The tremendous heterogeneity of the disease makes the genetics of RP complicated, thus rendering genotype-phenotype correlations not fully applicable yet. In addition to the multiplicity of mutations, in fact, different mutations in the same gene may cause different diseases. We will here review which genes are involved in the genesis of RP and how mutations can lead to retinal degeneration. In the future, a more thorough analysis of genetic and clinical data together with a better understanding of the genotype-phenotype correlation might allow to reveal important information with respect to the likelihood of disease development and choices of therapy. PMID:22131869

  18. A Hypoxia-Responsive Glial Cell–Specific Gene Therapy Vector for Targeting Retinal Neovascularization

    PubMed Central

    Biswal, Manas R.; Prentice, Howard M.; Dorey, C. Kathleen; Blanks, Janet C.

    2014-01-01

    Purpose. Müller cells, the major glial cell in the retina, play a significant role in retinal neovascularization in response to tissue hypoxia. We previously designed and tested a vector using a hypoxia-responsive domain and a glial fibrillary acidic protein (GFAP) promoter to drive green fluorescent protein (GFP) expression in Müller cells in the murine model of oxygen-induced retinopathy (OIR). This study compares the efficacy of regulated and unregulated Müller cell delivery of endostatin in preventing neovascularization in the OIR model. Methods. Endostatin cDNA was cloned into plasmids with hypoxia-regulated GFAP or unregulated GFAP promoters, and packaged into self-complementary adeno-associated virus serotype 2 vectors (scAAV2). Before placement in hyperoxia on postnatal day (P)7, mice were given intravitreal injections of regulated or unregulated scAAV2, capsid, or PBS. Five days after return to room air, on P17, neovascular and avascular areas, as well as expression of the transgene and vascular endothelial growth factor (VEGF), were compared in OIR animals treated with a vector, capsid, or PBS. Results. The hypoxia-regulated, glial-specific, vector-expressing endostatin reduced neovascularization by 93% and reduced the central vaso-obliteration area by 90%, matching the results with the unregulated GFAP-Endo vector. Retinas treated with the regulated endostatin vector expressed substantial amounts of endostatin protein, and significantly reduced VEGF protein. Endostatin production from the regulated vector was undetectable in retinas with undamaged vasculature. Conclusions. These findings suggest that the hypoxia-regulated, glial cell–specific vector expressing endostatin may be useful for treatment of neovascularization in proliferative diabetic retinopathy. PMID:25377223

  19. Cone-Specific Promoters for Gene Therapy of Achromatopsia and Other Retinal Diseases.

    PubMed

    Ye, Guo-Jie; Budzynski, Ewa; Sonnentag, Peter; Nork, T Michael; Sheibani, Nader; Gurel, Zafer; Boye, Sanford L; Peterson, James J; Boye, Shannon E; Hauswirth, William W; Chulay, Jeffrey D

    2016-01-01

    Adeno-associated viral (AAV) vectors containing cone-specific promoters have rescued cone photoreceptor function in mouse and dog models of achromatopsia, but cone-specific promoters have not been optimized for use in primates. Using AAV vectors administered by subretinal injection, we evaluated a series of promoters based on the human L-opsin promoter, or a chimeric human cone transducin promoter, for their ability to drive gene expression of green fluorescent protein (GFP) in mice and nonhuman primates. Each of these promoters directed high-level GFP expression in mouse photoreceptors. In primates, subretinal injection of an AAV-GFP vector containing a 1.7-kb L-opsin promoter (PR1.7) achieved strong and specific GFP expression in all cone photoreceptors and was more efficient than a vector containing the 2.1-kb L-opsin promoter that was used in AAV vectors that rescued cone function in mouse and dog models of achromatopsia. A chimeric cone transducin promoter that directed strong GFP expression in mouse and dog cone photoreceptors was unable to drive GFP expression in primate cones. An AAV vector expressing a human CNGB3 gene driven by the PR1.7 promoter rescued cone function in the mouse model of achromatopsia. These results have informed the design of an AAV vector for treatment of patients with achromatopsia.

  20. Gene Therapy in Patient-specific Stem Cell Lines and a Preclinical Model of Retinitis Pigmentosa With Membrane Frizzled-related Protein Defects

    PubMed Central

    Li, Yao; Wu, Wen-Hsuan; Hsu, Chun-Wei; Nguyen, Huy V; Tsai, Yi-Ting; Chan, Lawrence; Nagasaki, Takayuki; Maumenee, Irene H; Yannuzzi, Lawrence A; Hoang, Quan V; Hua, Haiqing; Egli, Dieter; Tsang, Stephen H

    2014-01-01

    Defects in Membrane Frizzled-related Protein (MFRP) cause autosomal recessive retinitis pigmentosa (RP). MFRP codes for a retinal pigment epithelium (RPE)-specific membrane receptor of unknown function. In patient-specific induced pluripotent stem (iPS)-derived RPE cells, precise levels of MFRP, and its dicistronic partner CTRP5, are critical to the regulation of actin organization. Overexpression of CTRP5 in naïve human RPE cells phenocopied behavior of MFRP-deficient patient RPE (iPS-RPE) cells. AAV8 (Y733F) vector expressing human MFRP rescued the actin disorganization phenotype and restored apical microvilli in patient-specific iPS-RPE cell lines. As a result, AAV-treated MFRP mutant iPS-RPE recovered pigmentation and transepithelial resistance. The efficacy of AAV-mediated gene therapy was also evaluated in Mfrprd6/Mfrprd6 mice—an established preclinical model of RP—and long-term improvement in visual function was observed in AAV-Mfrp-treated mice. This report is the first to indicate the successful use of human iPS-RPE cells as a recipient for gene therapy. The observed favorable response to gene therapy in both patient-specific cell lines, and the Mfrprd6/Mfrprd6 preclinical model suggests that this form of degeneration caused by MFRP mutations is a potential target for interventional trials. PMID:24895994

  1. Gene therapy in patient-specific stem cell lines and a preclinical model of retinitis pigmentosa with membrane frizzled-related protein defects.

    PubMed

    Li, Yao; Wu, Wen-Hsuan; Hsu, Chun-Wei; Nguyen, Huy V; Tsai, Yi-Ting; Chan, Lawrence; Nagasaki, Takayuki; Maumenee, Irene H; Yannuzzi, Lawrence A; Hoang, Quan V; Hua, Haiqing; Egli, Dieter; Tsang, Stephen H

    2014-09-01

    Defects in Membrane Frizzled-related Protein (MFRP) cause autosomal recessive retinitis pigmentosa (RP). MFRP codes for a retinal pigment epithelium (RPE)-specific membrane receptor of unknown function. In patient-specific induced pluripotent stem (iPS)-derived RPE cells, precise levels of MFRP, and its dicistronic partner CTRP5, are critical to the regulation of actin organization. Overexpression of CTRP5 in naïve human RPE cells phenocopied behavior of MFRP-deficient patient RPE (iPS-RPE) cells. AAV8 (Y733F) vector expressing human MFRP rescued the actin disorganization phenotype and restored apical microvilli in patient-specific iPS-RPE cell lines. As a result, AAV-treated MFRP mutant iPS-RPE recovered pigmentation and transepithelial resistance. The efficacy of AAV-mediated gene therapy was also evaluated in Mfrp(rd6)/Mfrp(rd6) mice--an established preclinical model of RP--and long-term improvement in visual function was observed in AAV-Mfrp-treated mice. This report is the first to indicate the successful use of human iPS-RPE cells as a recipient for gene therapy. The observed favorable response to gene therapy in both patient-specific cell lines, and the Mfrp(rd6)/Mfrp(rd6) preclinical model suggests that this form of degeneration caused by MFRP mutations is a potential target for interventional trials.

  2. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy.

    PubMed

    Nash, Benjamin M; Wright, Dale C; Grigg, John R; Bennetts, Bruce; Jamieson, Robyn V

    2015-04-01

    Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs.

  3. Preclinical potency and safety studies of an AAV2-mediated gene therapy vector for the treatment of MERTK associated retinitis pigmentosa.

    PubMed

    Conlon, Thomas J; Deng, Wen-Tao; Erger, Kirsten; Cossette, Travis; Pang, Ji-jing; Ryals, Renee; Clément, Nathalie; Cleaver, Brian; McDoom, Issam; Boye, Shannon E; Peden, Marc C; Sherwood, Mark B; Abernathy, Corinne R; Alkuraya, Fowzan S; Boye, Sanford L; Hauswirth, William W

    2013-03-01

    Abstract Proof of concept for MERTK gene replacement therapy has been demonstrated using different viral vectors in the Royal College of Surgeon (RCS) rat, a well characterized model of recessive retinitis pigmentosa that contains a mutation in the Mertk gene. MERTK plays a key role in renewal of photoreceptor outer segments (OS) by phagocytosis of shed OS tips. Mutations in MERTK cause impaired phagocytic activity and accumulation of OS debris in the interphotoreceptor space that ultimately leads to photoreceptor cell death. In the present study, we conducted a series of preclinical potency and GLP-compliant safety evaluations of an adeno-associated virus type 2 (AAV2) vector expressing human MERTK cDNA driven by the retinal pigment epithelium-specific, VMD2 promoter. We demonstrate the potency of the vector in RCS rats by improved electroretinogram (ERG) responses in treated eyes compared with contralateral untreated controls. Toxicology and biodistribution studies were performed in Sprague-Dawley (SD) rats injected with two different doses of AAV vectors and buffer control. Delivery of vector in SD rats did not result in a change in ERG amplitudes of rod and cone responses relative to balanced salt solution control-injected eyes, indicating that administration of AAV vector did not adversely affect normal retinal function. In vivo fundoscopic analysis and postmortem retinal morphology of the vector-injected eyes were normal compared with controls. Evaluation of blood smears showed the lack of transformed cells in the treated eyes. All injected eyes and day 1 blood samples were positive for vector genomes, and all peripheral tissues were negative. Our results demonstrate the potency and safety of the AAV2-VMD2-hMERTK vector in animal models tested. A GMP vector has been manufactured and is presently in clinical trial.

  4. An update on retinal laser therapy.

    PubMed

    Lock, Jane Huan-Jing; Fong, Kenneth Choong Sian

    2011-01-01

    Since its discovery in the 1940s, retinal photocoagulation has evolved immensely. Although the first photocoagulators used incandescent light, it was the invention of the laser that instigated the widespread use of photocoagulation for treatment of retinal diseases. Laser permits selection of electromagnetic wavelength, energy levels, spot size and pulse duration. These variables are crucial for accurate targeting of retinal tissue and prevention of detrimental side-effects such as central blind spots. There is ongoing clinical research dedicated to optimising such parameters and many innovative modes of laser delivery are now being offered. Laser photocoagulation is the mainstay of treatment for various retinal and macular diseases. Considering the escalating prevalence of such conditions and widespread use of photocoagulation, it is important for optometrists to grasp the basic principles and be aware of new developments in retinal laser therapy. © 2010 The Authors. Clinical and Experimental Optometry © 2010 Optometrists Association Australia.

  5. Developing an Outcome Measure With High Luminance for Optogenetics Treatment of Severe Retinal Degenerations and for Gene Therapy of Cone Diseases

    PubMed Central

    Cideciyan, Artur V.; Roman, Alejandro J.; Jacobson, Samuel G.; Yan, Boyuan; Pascolini, Michele; Charng, Jason; Pajaro, Simone; Nirenberg, Sheila

    2016-01-01

    Purpose To present stimuli with varied sizes, colors, and patterns over a large range of luminance. Methods The filter bar used in scotopic MP1 was replaced with a custom slide-in tray that introduces light from an external projector driven by an additional computer. MP1 software was modified to provide retinal tracking information to the computer driving the projector. Retinal tracking performance was evaluated by imaging the system input and the output simultaneously with a high-speed video system. Spatial resolution was measured with achromatic and chromatic grating/background combinations over scotopic and photopic ranges. Results The range of retinal illuminance achievable by the modification was up to 6.8 log photopic Trolands (phot-Td); however, in the current work, only a lower range over −4 to +3 log phot-Td was tested in human subjects. Optical magnification was optimized for low-vision testing with gratings from 4.5 to 0.2 cyc/deg. In normal subjects, spatial resolution driven by rods, short wavelength-sensitive (S-) cones, and long/middle wavelength-sensitive (L/M-) cones was obtained by the choice of adapting conditions and wavelengths of grating and background. Data from a patient with blue cone monochromacy was used to confirm mediation. Conclusions The modified MP1 can be developed into an outcome measure for treatments in patients with severe retinal degeneration, very low vision, and abnormal eye movements such as those for whom treatment with optogenetics is planned, as well as for patients with cone disorders such as blue cone monochromacy for whom treatment with gene therapy is planned to improve L/M-cone function above a normal complement of rod and S-cone function. PMID:27309625

  6. Developing an Outcome Measure With High Luminance for Optogenetics Treatment of Severe Retinal Degenerations and for Gene Therapy of Cone Diseases.

    PubMed

    Cideciyan, Artur V; Roman, Alejandro J; Jacobson, Samuel G; Yan, Boyuan; Pascolini, Michele; Charng, Jason; Pajaro, Simone; Nirenberg, Sheila

    2016-06-01

    To present stimuli with varied sizes, colors, and patterns over a large range of luminance. The filter bar used in scotopic MP1 was replaced with a custom slide-in tray that introduces light from an external projector driven by an additional computer. MP1 software was modified to provide retinal tracking information to the computer driving the projector. Retinal tracking performance was evaluated by imaging the system input and the output simultaneously with a high-speed video system. Spatial resolution was measured with achromatic and chromatic grating/background combinations over scotopic and photopic ranges. The range of retinal illuminance achievable by the modification was up to 6.8 log photopic Trolands (phot-Td); however, in the current work, only a lower range over -4 to +3 log phot-Td was tested in human subjects. Optical magnification was optimized for low-vision testing with gratings from 4.5 to 0.2 cyc/deg. In normal subjects, spatial resolution driven by rods, short wavelength-sensitive (S-) cones, and long/middle wavelength-sensitive (L/M-) cones was obtained by the choice of adapting conditions and wavelengths of grating and background. Data from a patient with blue cone monochromacy was used to confirm mediation. The modified MP1 can be developed into an outcome measure for treatments in patients with severe retinal degeneration, very low vision, and abnormal eye movements such as those for whom treatment with optogenetics is planned, as well as for patients with cone disorders such as blue cone monochromacy for whom treatment with gene therapy is planned to improve L/M-cone function above a normal complement of rod and S-cone function.

  7. Genes and Gene Therapy

    MedlinePlus

    ... correctly, a child can have a genetic disorder. Gene therapy is an experimental technique that uses genes to ... or prevent disease. The most common form of gene therapy involves inserting a normal gene to replace an ...

  8. Antiangiogenic Eye Gene Therapy.

    PubMed

    Corydon, Thomas J

    2015-08-01

    The idea of treating disease in humans with genetic material was conceived over two decades ago and with that a promising journey involving development and efficacy studies in cells and animals of a large number of novel therapeutic reagents unfolded. In the footsteps of this process, successful gene therapy treatment of genetic conditions in humans has shown clear signs of efficacy. Notably, significant advancements using gene supplementation and silencing strategies have been made in the field of ocular gene therapy, thereby pinpointing ocular gene therapy as one of the compelling "actors" bringing gene therapy to the clinic. Most of all, this success has been facilitated because of (1) the fact that the eye is an effortlessly accessible, exceedingly compartmentalized, and immune-privileged organ offering a unique advantage as a gene therapy target, and (2) significant progress toward efficient, sustained transduction of cells within the retina having been achieved using nonintegrating vectors based on recombinant adeno-associated virus and nonintegrating lentivirus vectors. The results from in vivo experiments and trials suggest that treatment of inherited retinal dystrophies, ocular angiogenesis, and inflammation with gene therapy can be both safe and effective. Here, the progress of ocular gene therapy is examined with special emphasis on the potential use of RNAi- and protein-based antiangiogenic gene therapy to treat exudative age-related macular degeneration.

  9. AAV8(Y733F)-mediated gene therapy in a Spata7 knockout mouse model of Leber congenital amaurosis and retinitis pigmentosa.

    PubMed

    Zhong, H; Eblimit, A; Moayedi, Y; Boye, S L; Chiodo, V A; Chen, Y; Li, Y; Nichols, R M; Hauswirth, W W; Chen, R; Mardon, G

    2015-08-01

    Loss of SPATA7 function causes the pathogenesis of Leber congenital amaurosis and retinitis pigmentosa. Spata7 knockout mice mimic human SPATA7-related retinal disease with apparent photoreceptor degeneration observed as early as postnatal day 15 (P15). To test the efficacy of adeno-associated virus (AAV)-mediated gene therapy for rescue of photoreceptor survival and function in Spata7 mutant mice, we employed the AAV8(Y733F) vector carrying hGRK1-driven full-length FLAG-tagged Spata7 cDNA to target both rod and cone photoreceptors. Following subretinal injection of this vector, FLAG-tagged SPATA7 was found to colocalize with endogenous SPATA7 in wild-type mice. In Spata7 mutant mice initially treated at P15, we observed improvement of photoresponse, photoreceptor ultrastructure and significant alleviation of photoreceptor degeneration. Furthermore, we performed treatments at P28 and P56 and found that all treatments (P15-P56) can ameliorate rod and cone loss in the long term (1 year); however, none efficiently protect photoreceptors from degeneration by 86 weeks of age as only a small amount of treated photoreceptors can survive to this time. This study demonstrates long-term improvement of photoreceptor function by AAV8(Y733F)-introduced Spata7 expression in a mouse model as potential treatment of the human disease, but also suggests that treated mutant photoreceptors still undergo progressive degeneration.

  10. AAV8(Y733F)-mediated gene therapy in a Spata7 knockout mouse model of Leber congenital amaurosis and retinitis pigmentosa

    PubMed Central

    Zhong, Hua; Eblimit, Aiden; Moayedi, Yalda; Boye, Sanford L; Chiodo, Vince A; Chen, Yiyun; Li, Yumei; Nichols, Ralph M; Hauswirth, William W; Chen, Rui; Mardon, Graeme

    2016-01-01

    Loss of SPATA7 function causes the pathogenesis of Leber congenital amaurosis and retinitis pigmentosa. Spata7 knockout mice mimic human SPATA7–related retinal disease with apparent photoreceptor degeneration observed as early as postnatal day 15 (P15). To test the efficacy of adeno-associated virus (AAV)-mediated gene therapy for rescue of photoreceptor survival and function in Spata7 mutant mice, we employed the AAV8(Y733F) vector carrying hGRK1-driven full-length FLAG-tagged Spata7 cDNA to target both rod and cone photoreceptors. Following subretinal injection of this vector, FLAG-tagged SPATA7 was found to co-localize with endogenous SPATA7 in wild-type mice. In Spata7 mutant mice initially treated at P15, we observed improvement of photoresponse, photoreceptor ultrastructure, and significant alleviation of photoreceptor degeneration. Furthermore we performed treatments at P28 and P56 and found that all treatments (P15-P56) can ameliorate rod and cone loss in the long term (1 year); however, none efficiently protect photoreceptors from degeneration by 86 weeks of age since only a small amount of treated photoreceptors can survive to this time. This study demonstrates long-term improvement of photoreceptor function by AAV8(Y733F)-introduced Spata7 expression in a mouse model as potential treatment of the human disease but also suggests that treated mutant photoreceptors still undergo progressive degeneration. PMID:25965394

  11. Gene Therapy

    MedlinePlus

    ... cells in an effort to treat or stop disease. Genes contain your DNA — the code that controls much of your body's form and function, from making you grow taller to regulating your body systems. Genes that don't work properly can cause disease. Gene therapy replaces a faulty gene or adds ...

  12. Stem Cell Therapies in Retinal Disorders

    PubMed Central

    Garg, Aakriti; Yang, Jin; Lee, Winston; Tsang, Stephen H.

    2017-01-01

    Stem cell therapy has long been considered a promising mode of treatment for retinal conditions. While human embryonic stem cells (ESCs) have provided the precedent for regenerative medicine, the development of induced pluripotent stem cells (iPSCs) revolutionized this field. iPSCs allow for the development of many types of retinal cells, including those of the retinal pigment epithelium, photoreceptors, and ganglion cells, and can model polygenic diseases such as age-related macular degeneration. Cellular programming and reprogramming technology is especially useful in retinal diseases, as it allows for the study of living cells that have genetic variants that are specific to patients’ diseases. Since iPSCs are a self-renewing resource, scientists can experiment with an unlimited number of pluripotent cells to perfect the process of targeted differentiation, transplantation, and more, for personalized medicine. Challenges in the use of stem cells are present from the scientific, ethical, and political realms. These include transplant complications leading to anatomically incorrect placement, concern for tumorigenesis, and incomplete targeting of differentiation leading to contamination by different types of cells. Despite these limitations, human ESCs and iPSCs specific to individual patients can revolutionize the study of retinal disease and may be effective therapies for conditions currently considered incurable. PMID:28157165

  13. Gene Therapy

    PubMed Central

    Scheller, E.L.; Krebsbach, P.H.

    2009-01-01

    Gene therapy is defined as the treatment of disease by transfer of genetic material into cells. This review will explore methods available for gene transfer as well as current and potential applications for craniofacial regeneration, with emphasis on future development and design. Though non-viral gene delivery methods are limited by low gene transfer efficiency, they benefit from relative safety, low immunogenicity, ease of manufacture, and lack of DNA insert size limitation. In contrast, viral vectors are nature’s gene delivery machines that can be optimized to allow for tissue-specific targeting, site-specific chromosomal integration, and efficient long-term infection of dividing and non-dividing cells. In contrast to traditional replacement gene therapy, craniofacial regeneration seeks to use genetic vectors as supplemental building blocks for tissue growth and repair. Synergistic combination of viral gene therapy with craniofacial tissue engineering will significantly enhance our ability to repair and replace tissues in vivo. PMID:19641145

  14. Gene therapy.

    PubMed

    Williamson, B

    1982-07-29

    Gene therapy is not yet possible, but may become feasible soon, particularly for well understood gene defects. Although treatment of a patient raises no ethical problems once it can be done well, changing the genes of an early embryo is more difficult, controversial and unlikely to be required clinically.

  15. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy

    PubMed Central

    Nash, Benjamin M.; Wright, Dale C.; Grigg, John R.; Bennetts, Bruce

    2015-01-01

    Retinal dystrophies (RDs) are degenerative diseases of the retina which have marked clinical and genetic heterogeneity. Common presentations among these disorders include night or colour blindness, tunnel vision and subsequent progression to complete blindness. The known causative disease genes have a variety of developmental and functional roles with mutations in more than 120 genes shown to be responsible for the phenotypes. In addition, mutations within the same gene have been shown to cause different disease phenotypes, even amongst affected individuals within the same family highlighting further levels of complexity. The known disease genes encode proteins involved in retinal cellular structures, phototransduction, the visual cycle, and photoreceptor structure or gene regulation. This review aims to demonstrate the high degree of genetic complexity in both the causative disease genes and their associated phenotypes, highlighting the more common clinical manifestation of retinitis pigmentosa (RP). The review also provides insight to recent advances in genomic molecular diagnosis and gene and cell-based therapies for the RDs. PMID:26835369

  16. Gene Therapy.

    PubMed

    Thorne, Barb; Takeya, Ryan; Vitelli, Francesca; Swanson, Xin

    2017-03-14

    Gene therapy refers to a rapidly growing field of medicine in which genes are introduced into the body to treat or prevent diseases. Although a variety of methods can be used to deliver the genetic materials into the target cells and tissues, modified viral vectors represent one of the more common delivery routes because of its transduction efficiency for therapeutic genes. Since the introduction of gene therapy concept in the 1970s, the field has advanced considerably with notable clinical successes being demonstrated in many clinical indications in which no standard treatment options are currently available. It is anticipated that the clinical success the field observed in recent years can drive requirements for more scalable, robust, cost effective, and regulatory-compliant manufacturing processes. This review provides a brief overview of the current manufacturing technologies for viral vectors production, drawing attention to the common upstream and downstream production process platform that is applicable across various classes of viral vectors and their unique manufacturing challenges as compared to other biologics. In addition, a case study of an industry-scale cGMP production of an AAV-based gene therapy product performed at 2,000 L-scale is presented. The experience and lessons learned from this largest viral gene therapy vector production run conducted to date as discussed and highlighted in this review should contribute to future development of commercial viable scalable processes for vial gene therapies.

  17. Gene therapy.

    PubMed

    Drugan, A; Miller, O J; Evans, M I

    1987-01-01

    Severe genetic disorders are potentially correctable by the addition of a normal gene into tissues. Although the technical problems involving integration, stable expression, and insertional damage to the treated cell are not yet fully solved, enough scientific progress has already been made to consider somatic cell gene therapy acceptable from both the ethical and scientific viewpoints. The resolutions to problems evolving from somatic cell gene therapy will help to overcome the technical difficulties encountered presently with germ line gene manipulation. This procedure would then become morally permissible as it will cause, in time, a reduction in the pool of abnormal genes in the population. Enhancement genetic engineering is technically feasible but morally unacceptable. Eugenic genetic engineering is not technically possible or ethically permissible in the foreseeable future.

  18. Gene therapy research in Asia.

    PubMed

    Deng, H-X; Wang, Y; Ding, Q-R; Li, D-L; Wei, Yu-Quan

    2017-09-07

    Gene therapy has shown great potential for the treatment of diseases that previously were either untreatable or treatable but not curable with conventional schemes. Recent progress in clinical gene therapy trials has emerged in various severe diseases, including primary immunodeficiencies, leukodystrophies, Leber's congenital amaurosis, haemophilia, as well as retinal dystrophy. The clinical transformation and industrialization of gene therapy in Asia have been remarkable and continue making steady progress. A total of six gene therapy-based products have been approved worldwide, including two drugs from Asia. This review aims to highlight recent progress in gene therapy clinical trials and discuss the prospects for the future in China and wider Asia.Gene Therapy advance online publication, 7 September 2017; doi:10.1038/gt.2017.62.

  19. Gene therapy for retinitis pigmentosa and Leber congenital amaurosis caused by defects in AIPL1: effective rescue of mouse models of partial and complete Aipl1 deficiency using AAV2/2 and AAV2/8 vectors

    PubMed Central

    Tan, Mei Hong; Smith, Alexander J.; Pawlyk, Basil; Xu, Xiaoyun; Liu, Xiaoqing; Bainbridge, James B.; Basche, Mark; McIntosh, Jenny; Tran, Hoai Viet; Nathwani, Amit; Li, Tiansen; Ali, Robin R.

    2009-01-01

    Defects in the photoreceptor-specific gene encoding aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) are clinically heterogeneous and present as Leber Congenital Amaurosis, the severest form of early-onset retinal dystrophy and milder forms of retinal dystrophies such as juvenile retinitis pigmentosa and dominant cone-rod dystrophy. [Perrault, I., Rozet, J.M., Gerber, S., Ghazi, I., Leowski, C., Ducroq, D., Souied, E., Dufier, J.L., Munnich, A. and Kaplan, J. (1999) Leber congenital amaurosis. Mol. Genet. Metab., 68, 200–208.] Although not yet fully elucidated, AIPL1 is likely to function as a specialized chaperone for rod phosphodiesterase (PDE). We evaluate whether AAV-mediated gene replacement therapy is able to improve photoreceptor function and survival in retinal degeneration associated with AIPL1 defects. We used two mouse models of AIPL1 deficiency simulating three different rates of photoreceptor degeneration. The Aipl1 hypomorphic (h/h) mouse has reduced Aipl1 levels and a relatively slow degeneration. Under light acceleration, the rate of degeneration in the Aipl1 h/h mouse is increased by 2–3-fold. The Aipl1−/− mouse has no functional Aipl1 and has a very rapid retinal degeneration. To treat the different rates of degeneration, two pseudotypes of recombinant adeno-associated virus (AAV) exhibiting different transduction kinetics are used for gene transfer. We demonstrate restoration of cellular function and preservation of photoreceptor cells and retinal function in Aipl1 h/h mice following gene replacement therapy using an AAV2/2 vector and in the light accelerated Aipl1 h/h model and Aipl1−/− mice using an AAV2/8 vector. We have thus established the potential of gene replacement therapy in varying rates of degeneration that reflect the clinical spectrum of disease. This is the first gene replacement study to report long-term rescue of a photoreceptor-specific defect and to demonstrate effective rescue of a rapid photoreceptor

  20. Developing Cellular Therapies for Retinal Degenerative Diseases

    PubMed Central

    Bharti, Kapil; Rao, Mahendra; Hull, Sara Chandros; Stroncek, David; Brooks, Brian P.; Feigal, Ellen; van Meurs, Jan C.; Huang, Christene A.; Miller, Sheldon S.

    2014-01-01

    Biomedical advances in vision research have been greatly facilitated by the clinical accessibility of the visual system, its ease of experimental manipulation, and its ability to be functionally monitored in real time with noninvasive imaging techniques at the level of single cells and with quantitative end-point measures. A recent example is the development of stem cell–based therapies for degenerative eye diseases including AMD. Two phase I clinical trials using embryonic stem cell–derived RPE are already underway and several others using both pluripotent and multipotent adult stem cells are in earlier stages of development. These clinical trials will use a variety of cell types, including embryonic or induced pluripotent stem cell–derived RPE, bone marrow– or umbilical cord–derived mesenchymal stem cells, fetal neural or retinal progenitor cells, and adult RPE stem cells–derived RPE. Although quite distinct, these approaches, share common principles, concerns and issues across the clinical development pipeline. These considerations were a central part of the discussions at a recent National Eye Institute meeting on the development of cellular therapies for retinal degenerative disease. At this meeting, emphasis was placed on the general value of identifying and sharing information in the so-called “precompetitive space.” The utility of this behavior was described in terms of how it could allow us to remove road blocks in the clinical development pipeline, and more efficiently and economically move stem cell–based therapies for retinal degenerative diseases toward the clinic. Many of the ocular stem cell approaches we discuss are also being used more broadly, for nonocular conditions and therefore the model we develop here, using the precompetitive space, should benefit the entire scientific community. PMID:24573369

  1. The Role of the Human Visual Cortex in Assessment of the Long-Term Durability of Retinal Gene Therapy in Follow-on RPE65 Clinical Trial Patients.

    PubMed

    Ashtari, Manzar; Nikonova, Elena S; Marshall, Kathleen A; Young, Gloria J; Aravand, Puya; Pan, Wei; Ying, Gui-Shuang; Willett, Aimee E; Mahmoudian, Mani; Maguire, Albert M; Bennett, Jean

    2017-06-01

    Gene therapy (GT) has offered immense hope to individuals who are visually impaired because of RPE65 mutations. Although GT has shown great success in clinical trials enrolling these individuals, evidence for stability and durability of this treatment over time is still unknown. Herein we explored the value of functional magnetic resonance imaging (fMRI) as an objective measure to assess independently the longevity of retinal GT. Individuals with RPE65 mutations who underwent GT in their worse-seeing eye in a phase 1 clinical trial received a second subretinal injection in their contralateral eye in a follow-on clinical trial. Functional magnetic resonance imaging (MRI) was performed longitudinally to assess brain responses of patients with RPE65 mutations after stimulation of their most recently treated eye before and 1 to 3 years after GT. Seven participants with RPE65 mutations who were part of the follow-on clinical trial gave informed consent to participate in a longitudinal neuroimaging fMRI study. All participants underwent fMRI using a 3-Tesla MRI system and a 32-channel head coil. Participants' cortical activations were assessed using a block design paradigm of contrast reversing checkerboard stimuli delivered using an MRI-compatible video system. The primary parameters being measured in this study were the qualitative and quantitative fMRI cortical activations produced by our population in response to the visual task. Functional MRI results showed minimal or no cortical responses before GT. Significant increase in cortical activation lasting at least 3 years after GT was observed for all participants. Repeated measures analysis showed significant associations between cortical activations and clinical measures such as full-field light sensitivity threshold for white, red, and blue colors; visual field; and pupillary light reflex. Participants with RPE65 mutations showed intact visual pathways, which became responsive and strengthened after treatment

  2. Genes and mutations causing retinitis pigmentosa

    PubMed Central

    Daiger, SP; Sullivan, LS; Bowne, SJ

    2013-01-01

    Retinitis pigmentosa (RP) is a heterogeneous set of inherited retinopathies with many disease-causing genes, many known mutations, and highly varied clinical consequences. Progress in finding treatments is dependent on determining the genes and mutations causing these diseases, which includes both gene discovery and mutation screening in affected individuals and families. Despite the complexity, substantial progress has been made in finding RP genes and mutations. Depending on the type of RP, and the technology used, it is possible to detect mutations in 30–80% of cases. One of the most powerful approaches to genetic testing is high-throughput ‘deep sequencing’, that is, next-generation sequencing (NGS). NGS has identified several novel RP genes but a substantial fraction of previously unsolved cases have mutations in genes that are known causes of retinal disease but not necessarily RP. Apparent discrepancy between the molecular defect and clinical findings may warrant reevaluation of patients and families. In this review, we summarize the current approaches to gene discovery and mutation detection for RP, and indicate pitfalls and unsolved problems. Similar considerations apply to other forms of inherited retinal disease. PMID:23701314

  3. Gene expression changes during retinal development and rod specification

    PubMed Central

    Carrigan, Matthew; Hokamp, Karsten; Farrar, G. Jane

    2015-01-01

    Purpose Retinitis pigmentosa (RP) typically results from individual mutations in any one of >70 genes that cause rod photoreceptor cells to degenerate prematurely, eventually resulting in blindness. Gene therapies targeting individual RP genes have shown efficacy at clinical trial; however, these therapies require the surviving photoreceptor cells to be viable and functional, and may be economically feasible for only the more commonly mutated genes. An alternative potential treatment strategy, particularly for late stage disease, may involve stem cell transplants into the photoreceptor layer of the retina. Rod progenitors from postnatal mouse retinas can be transplanted and can form photoreceptors in recipient adult retinas; optimal numbers of transplantable cells are obtained from postnatal day 3–5 (P3–5) retinas. These cells can also be expanded in culture; however, this results in the loss of photoreceptor potential. Gene expression differences between postnatal retinas, cultured retinal progenitor cells (RPCs), and rod photoreceptor precursors were investigated to identify gene expression patterns involved in the specification of rod photoreceptors. Methods Microarrays were used to investigate differences in gene expression between cultured RPCs that have lost photoreceptor potential, P1 retinas, and fresh P5 retinas that contain significant numbers of transplantable photoreceptors. Additionally, fluorescence-activated cell sorting (FACS) sorted Rho-eGFP-expressing rod photoreceptor precursors were compared with Rho-eGFP-negative cells from the same P5 retinas. Differential expression was confirmed with quantitative polymerase chain reaction (q-PCR). Results Analysis of the microarray data sets, including the use of t-distributed stochastic neighbor embedding (t-SNE) to identify expression pattern neighbors of key photoreceptor specific genes, resulted in the identification of 636 genes differentially regulated during rod specification. Forty-four of these

  4. Rearing Light Intensity Affects Inner Retinal Pathology in a Mouse Model of X-Linked Retinoschisis but Does Not Alter Gene Therapy Outcome.

    PubMed

    Marangoni, Dario; Yong, Zeng; Kjellström, Sten; Vijayasarathy, Camasamudram; A Sieving, Paul; Bush, Ronald A

    2017-03-01

    To test the effects of rearing light intensity on retinal function and morphology in the retinoschisis knockout (Rs1-KO) mouse model of X-linked retinoschisis, and whether it affects functional outcome of RS1 gene replacement. Seventy-six Rs1-KO mice were reared in either cyclic low light (LL, 20 lux) or moderate light (ML, 300 lux) and analyzed at 1 and 4 months. Retinal function was assessed by electroretinogram and cavity size by optical coherence tomography. Expression of inward-rectifier K+ channel (Kir4.1), water channel aquaporin-4 (AQP4), and glial fibrillary acidic protein (GFAP) were analyzed by Western blotting. In a separate study, Rs1-KO mice reared in LL (n = 29) or ML (n = 27) received a unilateral intravitreal injection of scAAV8-hRs-IRBP at 21 days, and functional outcome was evaluated at 4 months by electroretinogram. At 1 month, no functional or structural differences were found between LL- or ML-reared Rs1-KO mice. At 4 months, ML-reared Rs1-KO mice showed significant reduction of b-wave amplitude and b-/a-wave ratio with no changes in a-wave, and a significant increase in cavity size, compared to LL-reared animals. Moderate light rearing increased Kir4.1 expression in Rs1-KO mice by 4 months, but not AQP4 and GFAP levels. Administration of scAAV8-hRS1-IRBP to Rs1-KO mice showed similar improvement of inner retinal ERG function independent of LL or ML rearing. Rearing light conditions affect the development of retinal cavities and post-photoreceptor function in Rs1-KO mice. However, the effect of rearing light intensity does not interact with the efficacy of RS1 gene replacement in Rs1-KO mice.

  5. Rearing Light Intensity Affects Inner Retinal Pathology in a Mouse Model of X-Linked Retinoschisis but Does Not Alter Gene Therapy Outcome

    PubMed Central

    Marangoni, Dario; Yong, Zeng; Kjellström, Sten; Vijayasarathy, Camasamudram; A. Sieving, Paul; Bush, Ronald A.

    2017-01-01

    Purpose To test the effects of rearing light intensity on retinal function and morphology in the retinoschisis knockout (Rs1-KO) mouse model of X-linked retinoschisis, and whether it affects functional outcome of RS1 gene replacement. Methods Seventy-six Rs1-KO mice were reared in either cyclic low light (LL, 20 lux) or moderate light (ML, 300 lux) and analyzed at 1 and 4 months. Retinal function was assessed by electroretinogram and cavity size by optical coherence tomography. Expression of inward-rectifier K+ channel (Kir4.1), water channel aquaporin-4 (AQP4), and glial fibrillary acidic protein (GFAP) were analyzed by Western blotting. In a separate study, Rs1-KO mice reared in LL (n = 29) or ML (n = 27) received a unilateral intravitreal injection of scAAV8-hRs-IRBP at 21 days, and functional outcome was evaluated at 4 months by electroretinogram. Results At 1 month, no functional or structural differences were found between LL- or ML-reared Rs1-KO mice. At 4 months, ML-reared Rs1-KO mice showed significant reduction of b-wave amplitude and b-/a-wave ratio with no changes in a-wave, and a significant increase in cavity size, compared to LL-reared animals. Moderate light rearing increased Kir4.1 expression in Rs1-KO mice by 4 months, but not AQP4 and GFAP levels. Administration of scAAV8-hRS1-IRBP to Rs1-KO mice showed similar improvement of inner retinal ERG function independent of LL or ML rearing. Conclusions Rearing light conditions affect the development of retinal cavities and post-photoreceptor function in Rs1-KO mice. However, the effect of rearing light intensity does not interact with the efficacy of RS1 gene replacement in Rs1-KO mice. PMID:28297725

  6. Biology and therapy of inherited retinal degenerative disease: insights from mouse models.

    PubMed

    Veleri, Shobi; Lazar, Csilla H; Chang, Bo; Sieving, Paul A; Banin, Eyal; Swaroop, Anand

    2015-02-01

    Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases.

  7. Biology and therapy of inherited retinal degenerative disease: insights from mouse models

    PubMed Central

    Veleri, Shobi; Lazar, Csilla H.; Chang, Bo; Sieving, Paul A.; Banin, Eyal; Swaroop, Anand

    2015-01-01

    Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases. PMID:25650393

  8. Transcorneal Electrical Stimulation Therapy for Retinal Disease

    ClinicalTrials.gov

    2012-05-03

    Retinitis Pigmentosa; Macula Off; Primary Open Angle Glaucoma; Hereditary Macular Degeneration; Treated Retina Detachment; Retinal Artery Occlusion; Retinal Vein Occlusion; Non-Arthritic-Anterior-Ischemic Optic-Neuropathy; Hereditary Autosomal Dominant Optic Atrophy; Dry Age Related Macular Degeneration; Ischemic Macula Edema

  9. [Developments in gene delivery vectors for ocular gene therapy].

    PubMed

    Khabou, Hanen; Dalkara, Deniz

    2015-05-01

    Gene therapy is quickly becoming a reality applicable in the clinic for inherited retinal diseases. Its remarkable success in safety and efficacy, in clinical trials for Leber's congenital amaurosis (LCA) type II generated significant interest and opened up possibilities for a new era of retinal gene therapies. Success in these clinical trials was mainly due to the favorable characteristics of the retina as a target organ. The eye offers several advantages as it is readily accessible and has some degree of immune privilege making it suitable for application of viral vectors. The viral vectors most frequently used for retinal gene delivery are lentivirus, adenovirus and adeno-associated virus (AAV). Here we will discuss the use of these viral vectors in retinal gene delivery with a strong focus on favorable properties of AAV. Thanks to its small size, AAV diffuses well in the inter-neural matrix making it suitable for applications in neural retina. Building on this initial clinical success with LCA II, we have now many opportunities to extend this proof-of-concept to other retinal diseases using AAV as a vector. This article will discuss what are some of the most imminent cellular targets for such therapies and the AAV toolkit that has been built to target these cells successfully. We will also discuss some of the challenges that we face in translating AAV-based gene therapies to the clinic.

  10. Identification of genes and pathways involved in retinal neovascularization by microarray analysis of two animal models of retinal angiogenesis.

    PubMed

    Recchia, Franco M; Xu, Lili; Penn, John S; Boone, Braden; Dexheimer, Phillip J

    2010-02-01

    Comparative retinal gene expression analysis in two rodent models of oxygen-induced retinopathy (OIR) was performed to identify the genes and pathways involved in retinal neovascularization. Three independent experimental runs were conducted for each species, according to standard protocols for induction of OIR. Total retinal RNA was isolated at two time points, corresponding to the early response to relative hypoxia (P13 in mouse, P15 in rat) and to the later phase of maximum retinal neovascularization (P18 in mouse, P20 in rat) and was used to prepare labeled probes for hybridization. Gene expression was compared between normal and experimental conditions for each species at each time point. Probesets with a false-discovery rate of genes were confirmed by quantitative rtPCR. At the early time point, there were changes in 43 genes in each species, with two in common. Increased expression of members of the VEGF and ephrin receptor signaling pathways were identified in both models. At the later time point, there were changes in 26 genes in the rat and in 1622 in the mouse, with 13 in common. Four pathways were identified in both models. Genes and pathways known to be involved in angiogenesis, as well as other biologically plausible genes and pathways, were identified. This work serves as a comprehensive resource for the study of retinal neovascularization and identification of potential rational targets for antiangiogenic therapy.

  11. Identification of Genes and Pathways Involved in Retinal Neovascularization by Microarray Analysis of Two Animal Models of Retinal Angiogenesis

    PubMed Central

    Xu, Lili; Penn, John S.; Boone, Braden; Dexheimer, Phillip J.

    2010-01-01

    Purpose. Comparative retinal gene expression analysis in two rodent models of oxygen-induced retinopathy (OIR) was performed to identify the genes and pathways involved in retinal neovascularization. Methods. Three independent experimental runs were conducted for each species, according to standard protocols for induction of OIR. Total retinal RNA was isolated at two time points, corresponding to the early response to relative hypoxia (P13 in mouse, P15 in rat) and to the later phase of maximum retinal neovascularization (P18 in mouse, P20 in rat) and was used to prepare labeled probes for hybridization. Gene expression was compared between normal and experimental conditions for each species at each time point. Probesets with a false-discovery rate of ≤0.05 were considered significantly different and were classified as cellular functions or biological pathways. Changes in expression of selected genes were confirmed by quantitative rtPCR. Results. At the early time point, there were changes in 43 genes in each species, with two in common. Increased expression of members of the VEGF and ephrin receptor signaling pathways were identified in both models. At the later time point, there were changes in 26 genes in the rat and in 1622 in the mouse, with 13 in common. Four pathways were identified in both models. Conclusions. Genes and pathways known to be involved in angiogenesis, as well as other biologically plausible genes and pathways, were identified. This work serves as a comprehensive resource for the study of retinal neovascularization and identification of potential rational targets for antiangiogenic therapy. PMID:19834031

  12. Overview of retinal differentiation potential of mesenchymal stem cells: A promising approach for retinal cell therapy.

    PubMed

    Salehi, Hossein; Amirpour, Noushin; Razavi, Shahnaz; Esfandiari, Ebrahim; Zavar, Reihaneh

    2017-03-01

    Retinal disease caused by retinal cell apoptosis leads to irreversible vision loss. Stem cell investigation efforts have been made to solve and cure retinal disorders. There are several sources of stem cells which have been used in these experiments. Numerous studies demonstrated that transplanted stem cells can migrate into and integrate in different layers of retina. Among these, mesenchymal stem cells (MSCs) were considered a promising source for cell therapy. Here, we review the literature assessing the potential of MSCs to differentiate into retinal cells in vivo and in vitro as well as their clinical application. However, more investigation is required to define the protocols that optimize stem cell differentiation and their functional integration in the retina.

  13. Gene therapy: Myth or reality?

    PubMed

    Fischer, Alain

    2016-01-01

    Gene therapy has become a reality, although still a fragile one. Clinical benefit has been achieved over the last 17years in a limited number of medical conditions for which pathophysiological studies determined that they were favorable settings. They include inherited disorders of the immune system, leukodystrophies, possibly hemoglobinopathies, hemophilia B, and retinal dystrophies. Advances in the treatment of B-cell leukemias and lymphomas have also been achieved. Advances in vector development and possible usage of gene editing may lead to significant advances over the next years.

  14. Effects of Subretinal Gene Transfer at Different Time Points in a Mouse Model of Retinal Degeneration

    PubMed Central

    Dai, Xufeng; Zhang, Hua; Han, Juanjuan; He, Ying; Zhang, Yangyang; Qi, Yan; Pang, Ji-jing

    2016-01-01

    Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is necessary for photoreceptors to generate an important lipid component of their membranes. The absence of LPCAT1 results in early and rapid rod and cone degeneration. Retinal degeneration 11 (rd11) mice carry a mutation in the Lpcat1 gene, and are an excellent model of early-onset rapid retinal degeneration (RD). To date, no reports have documented gene therapy administration in the rd11 mouse model at different ages. In this study, the AAV8 (Y733F)-smCBA-Lpcat1 vector was subretinally injected at postnatal day (P) 10, 14, 18, or 22. Four months after injection, immunohistochemistry and analysis of retinal morphology showed that treatment at P10 rescued about 82% of the wild-type retinal thickness. However, the diffusion of the vector and the resulting rescue were limited to an area around the injection site that was only 31% of the total retinal area. Injection at P14 resulted in vector diffusion that covered approximately 84% of the retina, and we found that gene therapy was more effective against RD when exposure to light was limited before and after treatment. We observed long-term preservation of electroretinogram (ERG) responses, and preservation of retinal structure, indicating that early treatment followed by limited light exposure can improve gene therapy effectiveness for the eyes of rd11 mice. Importantly, delayed treatment still partially preserved M-cones, but not S-cones, and M-cones in the rd11 retina appeared to have a longer window of opportunity for effective preservation with gene therapy. These results provide important information regarding the effects of subretinal gene therapy in the mouse model of LPCAT1-deficiency. PMID:27228218

  15. Cone photoreceptors are the main targets for gene therapy of NPHP5 (IQCB1) or NPHP6 (CEP290) blindness: generation of an all-cone Nphp6 hypomorph mouse that mimics the human retinal ciliopathy.

    PubMed

    Cideciyan, Artur V; Rachel, Rivka A; Aleman, Tomas S; Swider, Malgorzata; Schwartz, Sharon B; Sumaroka, Alexander; Roman, Alejandro J; Stone, Edwin M; Jacobson, Samuel G; Swaroop, Anand

    2011-04-01

    Leber congenital amaurosis (LCA), a severe autosomal recessive childhood blindness, is caused by mutations in at least 15 genes. The most common molecular form is a ciliopathy due to NPHP6 (CEP290) mutations and subjects have profound loss of vision. A similarly severe phenotype occurs in the related ciliopathy NPHP5 (IQCB1)-LCA. Recent success of retinal gene therapy in one form of LCA prompted the question whether we know enough about human NPHP5 and NPHP6 disease to plan such treatment. We determined that there was early-onset rapid degeneration of rod photoreceptors in young subjects with these ciliopathies. Rod outer segment (OS) lamination, when detectable, was disorganized. Retinal pigment epithelium lipofuscin accumulation indicated that rods had existed in the past in most subjects. In contrast to early rod losses, the all-cone human fovea in NPHP5- and NPHP6-LCA of all ages retained cone nuclei, albeit with abnormal inner segments and OS. The rd16 mouse, carrying a hypomorphic Nphp6 allele, was a good model of the rod-dominant human extra-foveal retina. Rd16 mice showed normal genesis of photoreceptors, including the formation of cilia, followed by abnormal elaboration of OS and rapid degeneration. To produce a model of the all-cone human fovea in NPHP6-LCA, we generated rd16;Nrl-/- double-mutant mice. They showed substantially retained cone photoreceptors with disproportionate cone function loss, such as in the human disease. NPHP5- and NPHP6-LCA across a wide age spectrum are thus excellent candidates for cone-directed gene augmentation therapy, and the rd16;Nrl-/- mouse is an appropriate model for pre-clinical proof-of-concept studies.

  16. Cell-Based Therapy for Degenerative Retinal Disease.

    PubMed

    Zarbin, Marco

    2016-02-01

    Stem cell-derived retinal pigment epithelium (RPE) and photoreceptors (PRs) have restored vision in preclinical models of human retinal degenerative disease. This review discusses characteristics of stem cell therapy in the eye and the challenges to clinical implementation that are being confronted today. Based on encouraging results from Phase I/II trials, the first Phase II clinical trials of stem cell-derived RPE transplantation are underway. PR transplant experiments have demonstrated restoration of visual function in preclinical models of retinitis pigmentosa and macular degeneration, but also indicate that no single approach is likely to succeed in overcoming PR loss in all cases. A greater understanding of the mechanisms controlling synapse formation as well as the immunoreactivity of transplanted retinal cells is urgently needed.

  17. Advances in bone marrow stem cell therapy for retinal dysfunction.

    PubMed

    Park, Susanna S; Moisseiev, Elad; Bauer, Gerhard; Anderson, Johnathon D; Grant, Maria B; Zam, Azhar; Zawadzki, Robert J; Werner, John S; Nolta, Jan A

    2017-01-01

    The most common cause of untreatable vision loss is dysfunction of the retina. Conditions, such as age-related macular degeneration, diabetic retinopathy and glaucoma remain leading causes of untreatable blindness worldwide. Various stem cell approaches are being explored for treatment of retinal regeneration. The rationale for using bone marrow stem cells to treat retinal dysfunction is based on preclinical evidence showing that bone marrow stem cells can rescue degenerating and ischemic retina. These stem cells have primarily paracrine trophic effects although some cells can directly incorporate into damaged tissue. Since the paracrine trophic effects can have regenerative effects on multiple cells in the retina, the use of this cell therapy is not limited to a particular retinal condition. Autologous bone marrow-derived stem cells are being explored in early clinical trials as therapy for various retinal conditions. These bone marrow stem cells include mesenchymal stem cells, mononuclear cells and CD34(+) cells. Autologous therapy requires no systemic immunosuppression or donor matching. Intravitreal delivery of CD34(+) cells and mononuclear cells appears to be tolerated and is being explored since some of these cells can home into the damaged retina after intravitreal administration. The safety of intravitreal delivery of mesenchymal stem cells has not been well established. This review provides an update of the current evidence in support of the use of bone marrow stem cells as treatment for retinal dysfunction. The potential limitations and complications of using certain forms of bone marrow stem cells as therapy are discussed. Future directions of research include methods to optimize the therapeutic potential of these stem cells, non-cellular alternatives using extracellular vesicles, and in vivo high-resolution retinal imaging to detect cellular changes in the retina following cell therapy.

  18. EIAV-Based Retinal Gene Therapy in the shaker1 Mouse Model for Usher Syndrome Type 1B: Development of UshStat

    PubMed Central

    Zallocchi, Marisa; Binley, Katie; Lad, Yatish; Ellis, Scott; Widdowson, Peter; Iqball, Sharifah; Scripps, Vicky; Kelleher, Michelle; Loader, Julie; Miskin, James; Peng, You-Wei; Wang, Wei-Min; Cheung, Linda; Delimont, Duane; Mitrophanous, Kyriacos A.; Cosgrove, Dominic

    2014-01-01

    Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE) and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene. Subretinal injections of EIAV-CMV-GFP, EIAV-RK-GFP (photoreceptor specific), EIAV-CMV-MYO7A (UshStat) or EIAV-CMV-Null (control) vectors were performed in shaker1 mice. GFP and myosin VIIa expression was evaluated histologically. Photoreceptor function in EIAV-CMV-MYO7A treated eyes was determined by evaluating α-transducin translocation in photoreceptors in response to low light intensity levels, and protection from light induced photoreceptor degeneration was measured. The safety and tolerability of subretinally delivered UshStat was evaluated in macaques. Expression of GFP and myosin VIIa was confirmed in the RPE and photoreceptors in shaker1 mice following subretinal delivery of the EIAV-CMV-GFP/MYO7A vectors. The EIAV-CMV-MYO7A vector protected the shaker1 mouse photoreceptors from acute and chronic intensity light damage, indicated by a significant reduction in photoreceptor cell loss, and restoration of the α-transducin translocation threshold in the photoreceptors. Safety studies in the macaques demonstrated that subretinal delivery of UshStat is safe and well-tolerated. Subretinal delivery of EIAV-CMV-MYO7A (UshStat) rescues photoreceptor phenotypes in the shaker1 mouse. In addition, subretinally delivered UshStat is safe and well-tolerated in macaque safety studies These data support the clinical development of UshStat to treat Usher type 1B syndrome. PMID:24705452

  19. EIAV-based retinal gene therapy in the shaker1 mouse model for usher syndrome type 1B: development of UshStat.

    PubMed

    Zallocchi, Marisa; Binley, Katie; Lad, Yatish; Ellis, Scott; Widdowson, Peter; Iqball, Sharifah; Scripps, Vicky; Kelleher, Michelle; Loader, Julie; Miskin, James; Peng, You-Wei; Wang, Wei-Min; Cheung, Linda; Delimont, Duane; Mitrophanous, Kyriacos A; Cosgrove, Dominic

    2014-01-01

    Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE) and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene. Subretinal injections of EIAV-CMV-GFP, EIAV-RK-GFP (photoreceptor specific), EIAV-CMV-MYO7A (UshStat) or EIAV-CMV-Null (control) vectors were performed in shaker1 mice. GFP and myosin VIIa expression was evaluated histologically. Photoreceptor function in EIAV-CMV-MYO7A treated eyes was determined by evaluating α-transducin translocation in photoreceptors in response to low light intensity levels, and protection from light induced photoreceptor degeneration was measured. The safety and tolerability of subretinally delivered UshStat was evaluated in macaques. Expression of GFP and myosin VIIa was confirmed in the RPE and photoreceptors in shaker1 mice following subretinal delivery of the EIAV-CMV-GFP/MYO7A vectors. The EIAV-CMV-MYO7A vector protected the shaker1 mouse photoreceptors from acute and chronic intensity light damage, indicated by a significant reduction in photoreceptor cell loss, and restoration of the α-transducin translocation threshold in the photoreceptors. Safety studies in the macaques demonstrated that subretinal delivery of UshStat is safe and well-tolerated. Subretinal delivery of EIAV-CMV-MYO7A (UshStat) rescues photoreceptor phenotypes in the shaker1 mouse. In addition, subretinally delivered UshStat is safe and well-tolerated in macaque safety studies These data support the clinical development of UshStat to treat Usher type 1B syndrome.

  20. Let There Be Light: Gene and Cell Therapy for Blindness.

    PubMed

    Dalkara, Deniz; Goureau, Olivier; Marazova, Katia; Sahel, José-Alain

    2016-02-01

    Retinal degenerative diseases are a leading cause of irreversible blindness. Retinal cell death is the main cause of vision loss in genetic disorders such as retinitis pigmentosa, Stargardt disease, and Leber congenital amaurosis, as well as in complex age-related diseases such as age-related macular degeneration. For these blinding conditions, gene and cell therapy approaches offer therapeutic intervention at various disease stages. The present review outlines advances in therapies for retinal degenerative disease, focusing on the progress and challenges in the development and clinical translation of gene and cell therapies. A significant body of preclinical evidence and initial clinical results pave the way for further development of these cutting edge treatments for patients with retinal degenerative disorders.

  1. Let There Be Light: Gene and Cell Therapy for Blindness

    PubMed Central

    Dalkara, Deniz; Goureau, Olivier; Marazova, Katia; Sahel, José-Alain

    2016-01-01

    Retinal degenerative diseases are a leading cause of irreversible blindness. Retinal cell death is the main cause of vision loss in genetic disorders such as retinitis pigmentosa, Stargardt disease, and Leber congenital amaurosis, as well as in complex age-related diseases such as age-related macular degeneration. For these blinding conditions, gene and cell therapy approaches offer therapeutic intervention at various disease stages. The present review outlines advances in therapies for retinal degenerative disease, focusing on the progress and challenges in the development and clinical translation of gene and cell therapies. A significant body of preclinical evidence and initial clinical results pave the way for further development of these cutting edge treatments for patients with retinal degenerative disorders. PMID:26751519

  2. Gene Augmentation for X-Linked Retinitis Pigmentosa Caused by Mutations in RPGR

    PubMed Central

    Beltran, William A.; Cideciyan, Artur V.; Lewin, Alfred S.; Hauswirth, William W.; Jacobson, Samuel G.; Aguirre, Gustavo D.

    2015-01-01

    X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is a severe and early onset form of retinal degeneration, and no treatment is currently available. Recent evidence in two clinically relevant canine models shows that adeno-associated viral (AAV)-mediated RPGR gene transfer to rods and cones can prevent disease onset and rescue photoreceptors at early- and mid-stages of degeneration. There is thus a strong incentive for conducting long-term, preclinical efficacy and safety studies, while concomitantly pursuing the detailed phenotypic characterization of XLRP disease in patients that may benefit from such corrective therapy. PMID:25301933

  3. Subvisible retinal laser therapy: titration algorithm and tissue response.

    PubMed

    Lavinsky, Daniel; Sramek, Christopher; Wang, Jenny; Huie, Philip; Dalal, Roopa; Mandel, Yossi; Palanker, Daniel

    2014-01-01

    Laser therapy for diabetic macular edema and other retinal diseases has been used within a wide range of laser settings: from intense burns to nondamaging exposures. However, there has been no algorithm for laser dosimetry that could determine laser parameters yielding a predictable extent of tissue damage. This multimodal imaging and structural correlation study aimed to verify and calibrate a computational model-based titration algorithm for predictable laser dosimetry ranging from nondamaging to intense coagulative tissue effects. Endpoint Management, an algorithm based on a computational model of retinal photothermal damage, was used to set laser parameters for various levels of tissue effect. The algorithm adjusts both power and pulse duration to vary the expected level of thermal damage at different percentages of a reference titration energy dose. Experimental verification was conducted in Dutch Belted rabbits using a PASCAL Streamline 577 laser system. Titration was performed by adjusting laser power to produce a barely visible lesion at 20 ms pulse duration, which is defined as the nominal (100%) energy level. Tissue effects were then determined for energy levels of 170, 120, 100, 75, 50, and 30% of the nominal energy at 1 hour and 3, 7, 30, and 60 days after treatment. In vivo imaging included fundus autofluorescence, fluorescein angiography, and spectral-domain optical coherence tomography. Morphologic changes in tissue were analyzed using light microscopy, as well as scanning and transmission electron microscopy. One hundred and seventy percent and 120% levels corresponded to moderate and light burns, respectively, with damage to retinal pigment epithelium, photoreceptors, and at highest settings, to the inner retina. 50% to 75% lesions were typically subvisible ophthalmoscopically but detectable with fluorescein angiography and optical coherence tomography. Histology in these lesions demonstrated some selective damage to retinal pigment epithelium and

  4. Neuroprotective therapy for argon-laser-induced retinal injury

    NASA Astrophysics Data System (ADS)

    Belkin, Michael; Rosner, Mordechai; Solberg, Yoram; Turetz, Yosef

    1999-06-01

    Laser photocoagulation treatment of the central retina is often complicated by an immediate side effect of visual impairment, caused by the unavoidable laser-induced destruction of the normal tissue lying adjacent to the lesion and not affected directly by the laser beam. Furthermore, accidental laser injuries are at present untreatable. A neuroprotective therapy for salvaging the normal tissue might enhance the benefit obtained from treatment and allow safe perifoveal photocoagulation. We have developed a rat model for studying the efficacy of putative neuroprotective compounds in ameliorating laser-induced retinal damage. Four compounds were evaluated: the corticosteroid methylprednisolone, the glutamate-receptor blocker MK-801, the anti-oxidant enzyme superoxide dismutase, and the calcim-overload antagonist flunarizine. The study was carried out in two steps: in the first, the histopathological development of retinal laser injuries was studied. Argon laser lesions were inflicted in the retinas of 18 pigmented rats. The animals were sacrificed after 3, 20 or 60 days and their retinal lesions were evaluated under the light microscope. The laser injury mainly involved the outer layers of the retina, where it destroyed significant numbers of photoreceptor cells. Over time, evidence of two major histopathological processes was observed: traction of adjacent nomral retinal cells into the central area of the lesion forming an internal retinal bulging, and a retinal pigmented epithelial proliferative reaction associated with subretinal neovascularization and invations of the retinal lesion site by phagocytes. The neuroprotective effects of each of the four compounds were verified in a second step of the study. For each drug tested, 12 rats were irradiated wtih argon laser inflictions: six of them received the tested agent while the other six were treated with the corresponding vehicle. Twenty days after laser expsoure, the rats were sacrificed and their lesions were

  5. Gene therapy for blindness.

    PubMed

    Sahel, José-Alain; Roska, Botond

    2013-07-08

    Sight-restoring therapy for the visually impaired and blind is a major unmet medical need. Ocular gene therapy is a rational choice for restoring vision or preventing the loss of vision because most blinding diseases originate in cellular components of the eye, a compartment that is optimally suited for the delivery of genes, and many of these diseases have a genetic origin or genetic component. In recent years we have witnessed major advances in the field of ocular gene therapy, and proof-of-concept studies are under way to evaluate the safety and efficacy of human gene therapies. Here we discuss the concepts and recent advances in gene therapy in the retina. Our review discusses traditional approaches such as gene replacement and neuroprotection and also new avenues such as optogenetic therapies. We conjecture that advances in gene therapy in the retina will pave the way for gene therapies in other parts of the brain.

  6. The gene therapy revolution in ophthalmology

    PubMed Central

    Al-Saikhan, Fahad I.

    2013-01-01

    The advances in gene therapy hold significant promise for the treatment of ophthalmic conditions. Several studies using animal models have been published. Animal models on retinitis pigmentosa, Leber’s Congenital Amaurosis (LCA), and Stargardt disease have involved the use of adeno-associated virus (AAV) to deliver functional genes into mice and canines. Mice models have been used to show that a mutation in cGMP phosphodiesterase that results in retinitis pigmentosa can be corrected using rAAV vectors. Additionally, rAAV vectors have been successfully used to deliver ribozyme into mice with a subsequent improvement in autosomal dominant retinitis pigmentosa. By using dog models, researchers have made progress in studying X-linked retinitis pigmentosa which results from a RPGR gene mutation. Mouse and canine models have also been used in the study of LCA. The widely studied form of LCA is LCA2, resulting from a mutation in the gene RPE65. Mice and canines that were injected with normal copies of RPE65 gene showed signs such as improved retinal pigment epithelium transduction, visual acuity, and functional recovery. Studies on Stargardt disease have shown that mutations in the ABCA4 gene can be corrected with AAV vectors, or nanoparticles. Gene therapy for the treatment of red–green color blindness was successful in squirrel monkeys. Plans are at an advanced stage to begin clinical trials. Researchers have also proved that CD59 can be used with AMD. Gene therapy is also able to treat primary open angle glaucoma (POAG) in animal models, and studies show it is economically viable. PMID:24227970

  7. The gene therapy revolution in ophthalmology.

    PubMed

    Al-Saikhan, Fahad I

    2013-04-01

    The advances in gene therapy hold significant promise for the treatment of ophthalmic conditions. Several studies using animal models have been published. Animal models on retinitis pigmentosa, Leber's Congenital Amaurosis (LCA), and Stargardt disease have involved the use of adeno-associated virus (AAV) to deliver functional genes into mice and canines. Mice models have been used to show that a mutation in cGMP phosphodiesterase that results in retinitis pigmentosa can be corrected using rAAV vectors. Additionally, rAAV vectors have been successfully used to deliver ribozyme into mice with a subsequent improvement in autosomal dominant retinitis pigmentosa. By using dog models, researchers have made progress in studying X-linked retinitis pigmentosa which results from a RPGR gene mutation. Mouse and canine models have also been used in the study of LCA. The widely studied form of LCA is LCA2, resulting from a mutation in the gene RPE65. Mice and canines that were injected with normal copies of RPE65 gene showed signs such as improved retinal pigment epithelium transduction, visual acuity, and functional recovery. Studies on Stargardt disease have shown that mutations in the ABCA4 gene can be corrected with AAV vectors, or nanoparticles. Gene therapy for the treatment of red-green color blindness was successful in squirrel monkeys. Plans are at an advanced stage to begin clinical trials. Researchers have also proved that CD59 can be used with AMD. Gene therapy is also able to treat primary open angle glaucoma (POAG) in animal models, and studies show it is economically viable.

  8. Myocardial gene therapy

    NASA Astrophysics Data System (ADS)

    Isner, Jeffrey M.

    2002-01-01

    Gene therapy is proving likely to be a viable alternative to conventional therapies in coronary artery disease and heart failure. Phase 1 clinical trials indicate high levels of safety and clinical benefits with gene therapy using angiogenic growth factors in myocardial ischaemia. Although gene therapy for heart failure is still at the pre-clinical stage, experimental data indicate that therapeutic angiogenesis using short-term gene expression may elicit functional improvement in affected individuals.

  9. Recent Advances of Stem Cell Therapy for Retinitis Pigmentosa

    PubMed Central

    He, Yuxi; Zhang, Yan; Liu, Xin; Ghazaryan, Emma; Li, Ying; Xie, Jianan; Su, Guanfang

    2014-01-01

    Retinitis pigmentosa (RP) is a group of inherited retinal disorders characterized by progressive loss of photoreceptors and eventually leads to retina degeneration and atrophy. Until now, the exact pathogenesis and etiology of this disease has not been clear, and many approaches for RP therapies have been carried out in animals and in clinical trials. In recent years, stem cell transplantation-based attempts made some progress, especially the transplantation of bone marrow-derived mesenchymal stem cells (BMSCs). This review will provide an overview of stem cell-based treatment of RP and its main problems, to provide evidence for the safety and feasibility for further clinical treatment. PMID:25141102

  10. Using induced pluripotent stems cells to understand retinal ciliopathy disease mechanisms and develop therapies

    PubMed Central

    Ramsden, Conor; Jovanovic, Katarina; Coffey, Peter J.; Hardcastle, Alison J.; Cheetham, Michael E.

    2016-01-01

    The photoreceptor cells in the retina have a highly specialized sensory cilium, the outer segment, which is important for detecting light. Mutations in cilia related genes often result in retinal degeneration. The ability to reprogram human cells into induced pluripotent stem cells (iPSCs) and then differentiate them into a wide range of different cell types has revolutionized our ability to study human disease. To date, however, the challenge of producing fully differentiated photoreceptors in vitro has limited the application of this technology in studying retinal degeneration. In this review we will discuss recent advances in stem cell technology and photoreceptor differentiation. In particular, the development of photoreceptors with rudimentary outer segments that can be used to understand disease mechanisms and as an important model to test potential new therapies for inherited retinal ciliopathies. PMID:27911706

  11. Gene therapy for vision loss -- recent developments.

    PubMed

    Stieger, Knut; Lorenz, Birgit

    2010-11-01

    Retinal gene therapy mediated by adeno-associated virus (AAV) based gene transfer was recently proven to improve photoreceptor function in one form of inherited retinal blinding disorder associated with mutations in the RPE65 gene. Several clinical trials are currently ongoing, and more than 30 patients have been treated to date. Even though only a very limited number of patients will greatly benefit from this still experimental treatment protocol, the technique itself has been shown to be safe and will likely be used in other retinal disorders in the near future. A canine model for achromatopsia has been treated successfully as well as mouse models for different forms of Leber congenital amaurosis (LCA). For patients with autosomal dominant retinitis pigmentosa (adRP), a combined gene knockdown and gene addition therapy is being developed using RNA interference to block mRNA of the mutant allele. For those patients suffering from RP with unknown mutations, an AAV based transfer of bacterial forms of rhodopsin in the central retina might be an option to reactivate residual cones in the future.

  12. Gene therapy review.

    PubMed

    Moss, Joseph Anthony

    2014-01-01

    The use of genes to treat disease, more commonly known as gene therapy, is a valid and promising tool to manage and treat diseases that conventional drug therapies cannot cure. Gene therapy holds the potential to control a wide range of diseases, including cystic fibrosis, heart disease, diabetes, cancer, and blood diseases. This review assesses the current status of gene therapy, highlighting therapeutic methodologies and applications, terminology, and imaging strategies. This article presents an overview of roadblocks associated with each therapeutic methodology, along with some of the scientific, social, and ethical issues associated with gene therapy.

  13. Highly efficient retinal gene delivery with helper-dependent adenoviral vectors

    PubMed Central

    Lam, Simon; Cao, Huibi; Wu, Jing; Duan, Rongqi; Hu, Jim

    2015-01-01

    There have been significant advancements in the field of retinal gene therapy in the past several years. In particular, therapeutic efficacy has been achieved in three separate human clinical trials conducted to assess the ability of adeno-associated viruses (AAV) to treat of a type of Leber’s congenital amaurosis caused by RPE65 mutations. However, despite the success of retinal gene therapy with AAV, challenges remain for delivering large therapeutic genes or genes requiring long DNA regulatory elements for controlling their expression. For example, Stargardt’s disease, a form of juvenile macular degeneration, is caused by defects in ABCA4, a gene that is too large to be packaged in AAV. Therefore, we investigated the ability of helper dependent adenovirus (HD-Ad) to deliver genes to the retina as it has a much larger transgene capacity. Using an EGFP reporter, our results showed that HD-Ad can transduce the entire retinal epithelium of a mouse using a dose of only 1 × 105 infectious units and maintain transgene expression for at least 4 months. The results demonstrate that HD-Ad has the potential to be an effective vector for the gene therapy of the retina. PMID:26161435

  14. Gene panel sequencing in Brazilian patients with retinitis pigmentosa.

    PubMed

    Costa, Kárita Antunes; Salles, Mariana Vallim; Whitebirch, Chris; Chiang, John; Sallum, Juliana Maria Ferraz

    2017-01-01

    Retinal dystrophies constitute a group of diseases characterized by clinical variability and pronounced genetic heterogeneity. Retinitis pigmentosa is the most common subtype of hereditary retinal dystrophy and is characterized by a progressive loss of peripheral field vision (Tunnel Vision), eventual loss of central vision, and progressive night blindness. The characteristics of the fundus changes include bone-spicule formations, attenuated blood vessels, reduced and/or abnormal electroretinograms, changes in structure imaged by optical coherence tomography, and subjective changes in visual function. The different syndromic and nonsyndromic forms of retinal dystrophies can be attributed to mutations in more than 250 genes. Molecular diagnosis for patients with retinitis pigmentosa has been hampered by extreme genetic and clinical heterogeneity between retinitis pigmentosa and other forms of retinal dystrophies. Next generation sequencing (NGS) technologies are among the most promising techniques to identify pathogenic variations in retinal dystrophies. The purpose of this study was to discover the molecular diagnosis for Brazilian patients clinically diagnosed with a retinitis pigmentosa pattern of inheritance by using NGS technologies. Sixteen patients with the clinical diagnosis of retinitis pigmentosa were included in the study. Their DNA was sequenced in a panel with 132 genes related to retinal dystrophies using the Illumina(®) platform. Sequence analysis and variation calling was performed using Soft Genetics(®), NextGene, and Geneticist Assistant software. The criteria for pathogenicity analysis were established according to the results of prediction programs (Polyphen 2, Mutation taster and MetaCore™) and comparison of pathogenic variations found with databases. The identified potentially pathogenic variations were all confirmed by Sanger sequencing. There were 89 variations predicted as pathogenic, but only 10 of them supported the conclusion of the

  15. Delivery of antioxidant enzyme genes to protect against ischemia/reperfusion-induced injury to retinal microvasculature.

    PubMed

    Chen, Baihua; Caballero, Sergio; Seo, Soojung; Grant, Maria B; Lewin, Alfred S

    2009-12-01

    Retinal ischemia/reperfusion (I/R) injury results in the generation of reactive oxygen species (ROS). The aim of this study was to investigate whether delivery of the manganese superoxide dismutase gene (SOD2) or the catalase gene (CAT) could rescue the retinal vascular damage induced by I/R in mice. I/R injury to the retina was induced in mice by elevating intraocular pressure for 2 hours, and reperfusion was established immediately afterward. One eye of each mouse was pretreated with plasmids encoding manganese superoxide dismutase or catalase complexed with cationic liposomes and delivered by intravitreous injection 48 hours before initiation of the procedure. Superoxide ion, hydrogen peroxide, and 4-hydroxynonenal (4-HNE) protein modifications were measured by fluorescence staining, immunohistochemistry, and Western blot analysis 1 day after the I/R injury. At 7 days after injury, retinal vascular cell apoptosis and acellular capillaries were quantitated. Superoxide ion, hydrogen peroxide, and 4-HNE protein modifications increased at 24 hours after I/R injury. Administration of plasmids encoding SOD2 or CAT significantly reduced levels of superoxide ion, hydrogen peroxide, and 4-HNE. Retinal vascular cell apoptosis and acellular capillary numbers increased greatly by 7 days after the injury. Delivery of SOD2 or CAT inhibited the I/R-induced apoptosis of retinal vascular cell and retinal capillary degeneration. Delivery of antioxidant genes inhibited I/R-induced retinal capillary degeneration, apoptosis of vascular cells, and ROS production, suggesting that antioxidant gene therapy might be a treatment for I/R-related disease.

  16. Delivery of Antioxidant Enzyme Genes to Protect against Ischemia/Reperfusion-Induced Injury to Retinal Microvasculature

    PubMed Central

    Chen, Baihua; Caballero, Sergio; Seo, Soojung; Grant, Maria B.; Lewin, Alfred S.

    2013-01-01

    Purpose Retinal ischemia/reperfusion (I/R) injury results in the generation of reactive oxygen species (ROS). The aim of this study was to investigate whether delivery of the manganese superoxide dismutase gene (SOD2) or the catalase gene (CAT) could rescue the retinal vascular damage induced by I/R in mice. Methods I/R injury to the retina was induced in mice by elevating intraocular pressure for 2 hours, and reperfusion was established immediately afterward. One eye of each mouse was pretreated with plasmids encoding manganese superoxide dismutase or catalase complexed with cationic liposomes and delivered by intravitreous injection 48 hours before initiation of the procedure. Superoxide ion, hydrogen peroxide, and 4-hydroxynonenal (4-HNE) protein modifications were measured by fluorescence staining, immunohistochemistry, and Western blot analysis 1 day after the I/R injury. At 7 days after injury, retinal vascular cell apoptosis and acellular capillaries were quantitated. Results Superoxide ion, hydrogen peroxide, and 4-HNE protein modifications increased at 24 hours after I/R injury. Administration of plasmids encoding SOD2 or CAT significantly reduced levels of superoxide ion, hydrogen peroxide, and 4-HNE. Retinal vascular cell apoptosis and acellular capillary numbers increased greatly by 7 days after the injury. Delivery of SOD2 or CAT inhibited the I/R-induced apoptosis of retinal vascular cell and retinal capillary degeneration. Conclusions Delivery of antioxidant genes inhibited I/R-induced retinal capillary degeneration, apoptosis of vascular cells, and ROS production, suggesting that antioxidant gene therapy might be a treatment for I/R-related disease. PMID:19628743

  17. Retinal Vasculitis

    PubMed Central

    Rosenbaum, James T.; Sibley, Cailin H.; Lin, Phoebe

    2016-01-01

    Purpose of review Ophthalmologists and rheumatologists frequently miscommunicate in consulting on patients with retinal vasculitis. This report seeks to establish a common understanding of the term, retinal vasculitis, and to review recent papers on this diagnosis. Recent findings 1) The genetic basis of some rare forms of retinal vascular disease have recently been described. Identified genes include CAPN5, TREX1, and TNFAIP3; 2) Behçet’s disease is a systemic illness that is very commonly associated with occlusive retinal vasculitis; 3) retinal imaging including fluorescein angiography and other newer imaging modalities has proven crucial to the identification and characterization of retinal vasculitis and its complications; 4) although monoclonal antibodies to IL-17A or IL-1 beta failed in trials for Behçet’s disease, antibodies to TNF alpha, either infliximab or adalimumab, have demonstrated consistent benefit in managing this disease. Interferon treatment and B cell depletion therapy via rituximab may be beneficial in certain types of retinal vasculitis. Summary Retinal vasculitis is an important entity for rheumatologists to understand. Retinal vasculitis associated with Behçet’s disease responds to monoclonal antibodies that neutralize TNF, but the many other forms of non-infectious retinal vasculitis may require alternate therapeutic management. PMID:26945335

  18. Selective retinal therapy with a continuous line scanning laser

    NASA Astrophysics Data System (ADS)

    Paulus, Yannis M.; Jain, ATul; Gariano, Ray F.; Nomoto, Hiroyuki; Schuele, Georg; Sramek, Christopher; Charalel, Resmi; Palanker, Daniel

    2010-02-01

    This study evaluates the effects of exposure duration, beam diameter, and power on the safety, selectivity, and healing of retinal lesions created using a continuous line scanning laser. A 532 nm laser (PASCALTM) with retinal beam diameters of 40 and 66 μm was applied to 60 eyes of 30 Dutch-Belted rabbits. Retinal exposure duration varied from 15 to 60 μs. Lesions were acutely assessed by ophthalmoscopy and fluorescein angiography (FA). RPE flatmounts were evaluated with live-dead fluorescent assay (LD). Histological analysis was performed at 1 hour, 1 and 3 days, 1 and 2 weeks, and 1 and 2 months following laser treatment. Ophthalmoscopic visibility (OV) of the lesions corresponded to photoreceptor damage on histological analysis at 1 hour. In subvisible lesions, FA and LD yielded similar thresholds of RPE damage. The ratios of the threshold of rupture and of OV to FA visibility (measures of safety and selectivity) increased with decreasing duration and beam diameter. Above the threshold of OV, histology showed focal RPE damage and photoreceptor loss at one day without inner retinal effects. By one week, continuity of photoreceptor and RPE layers was restored. By 1 month, photoreceptors appeared normal while hypertrophy and hyperpigmentation of the RPE persisted. Retinal therapy with a fast scanning continuous laser achieves selective targeting of the RPE and, at higher power, of the photoreceptors. The damage zone in the photoreceptor layer is quickly filled-in, likely due to photoreceptor migration from adjacent zones. Continuous scanning laser can treat large retinal areas within standard eye fixation time.

  19. Retinal gene delivery by adeno-associated virus (AAV) vectors: Strategies and applications.

    PubMed

    Schön, Christian; Biel, Martin; Michalakis, Stylianos

    2015-09-01

    Adeno-associated virus (AAV) vectors are the most widely used vehicle systems for neuronal gene transfer. This popularity is based on the non-pathogenic nature of AAVs and their versatility making them a multifunctional vector system for basic research and clinical applications. AAVs are successfully applied in clinical and pre-clinical gene therapy studies for inherited retinal disorders. Their excellent transduction profile and efficiency also boosted the use of AAV vectors in basic research. The AAV vector system can be easily modified and adjusted at multiple levels to allow for optimized and specific gene expression in target cells. Here, we will provide an overview on the AAV vector system and its applications focusing on gene transfer into retinal cells. Furthermore, we will outline and discuss strategies for the optimization of AAV gene transfer by modifications to the AAV vector expression cassette, the AAV capsid or the routes of vector administration.

  20. Harnessing the Potential of Human Pluripotent Stem Cells and Gene Editing for the Treatment of Retinal Degeneration.

    PubMed

    Ovando-Roche, Patrick; Georgiadis, Anastasios; Smith, Alexander J; Pearson, Rachael A; Ali, Robin R

    2017-01-01

    A major cause of visual disorders is dysfunction and/or loss of the light-sensitive cells of the retina, the photoreceptors. To develop better treatments for patients, we need to understand how inherited retinal disease mutations result in the dysfunction of photoreceptors. New advances in the field of stem cell and gene editing research offer novel ways to model retinal dystrophies in vitro and present opportunities to translate basic biological insights into therapies. This brief review will discuss some of the issues that should be taken into account when carrying out disease modelling and gene editing of retinal cells. We will discuss (i) the use of human induced pluripotent stem cells (iPSCs) for disease modelling and cell therapy; (ii) the importance of using isogenic iPSC lines as controls; (iii) CRISPR/Cas9 gene editing of iPSCs; and (iv) in vivo gene editing using AAV vectors. Ground-breaking advances in differentiation of iPSCs into retinal organoids and methods to derive mature light sensitive photoreceptors from iPSCs. Furthermore, single AAV systems for in vivo gene editing have been developed which makes retinal in vivo gene editing therapy a real prospect. Genome editing is becoming a valuable tool for disease modelling and in vivo gene editing in the retina.

  1. Retinal remodeling.

    PubMed

    Jones, B W; Kondo, M; Terasaki, H; Lin, Y; McCall, M; Marc, R E

    2012-07-01

    Retinal photoreceptor degeneration takes many forms. Mutations in rhodopsin genes or disorders of the retinal pigment epithelium, defects in the adenosine triphosphate binding cassette transporter, ABCR gene defects, receptor tyrosine kinase defects, ciliopathies and transport defects, defects in both transducin and arrestin, defects in rod cyclic guanosine 3',5'-monophosphate phosphodiesterase, peripherin defects, defects in metabotropic glutamate receptors, synthetic enzymatic defects, defects in genes associated with signaling, and many more can all result in retinal degenerative disease like retinitis pigmentosa (RP) or RP-like disorders. Age-related macular degeneration (AMD) and AMD-like disorders are possibly due to a constellation of potential gene targets and gene/gene interactions, while other defects result in diabetic retinopathy or glaucoma. However, all of these insults as well as traumatic insults to the retina result in retinal remodeling. Retinal remodeling is a universal finding subsequent to retinal degenerative disease that results in deafferentation of the neural retina from photoreceptor input as downstream neuronal elements respond to loss of input with negative plasticity. This negative plasticity is not passive in the face of photoreceptor degeneration, with a phased revision of retinal structure and function found at the molecular, synaptic, cell, and tissue levels involving all cell classes in the retina, including neurons and glia. Retinal remodeling has direct implications for the rescue of vision loss through bionic or biological approaches, as circuit revision in the retina corrupts any potential surrogate photoreceptor input to a remnant neural retina. However, there are a number of potential opportunities for intervention that are revealed through the study of retinal remodeling, including therapies that are designed to slow down photoreceptor loss, interventions that are designed to limit or arrest remodeling events, and

  2. Gene therapy for haemophilia.

    PubMed

    Sharma, Akshay; Easow Mathew, Manu; Sriganesh, Vasumathi; Neely, Jessica A; Kalipatnapu, Sasank

    2014-11-14

    Haemophilia is a genetic disorder which is characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy has recently been prompted as a curative treatment modality. To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B. We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of last search: 06 November 2014. Eligible trials included randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX. No trials of gene therapy for haemophilia were found. No trials of gene therapy for haemophilia were identified. No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the effects of gene therapy for haemophilia. Gene therapy for haemophilia is still in its nascent stages and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

  3. AAV-mediated gene therapy in Dystrophin-Dp71 deficient mouse leads to blood-retinal barrier restoration and oedema reabsorption.

    PubMed

    Vacca, Ophélie; Charles-Messance, Hugo; El Mathari, Brahim; Sene, Abdoulaye; Barbe, Peggy; Fouquet, Stéphane; Aragón, Jorge; Darche, Marie; Giocanti-Aurégan, Audrey; Paques, Michel; Sahel, José-Alain; Tadayoni, Ramin; Montañez, Cecilia; Dalkara, Deniz; Rendon, Alvaro

    2016-07-15

    Dystrophin-Dp71 being a key membrane cytoskeletal protein, expressed mainly in Müller cells that provide a mechanical link at the Müller cell membrane by direct binding to actin and a transmembrane protein complex. Its absence has been related to blood-retinal barrier (BRB) permeability through delocalization and down-regulation of the AQP4 and Kir4.1 channels (1). We have previously shown that the adeno-associated virus (AAV) variant, ShH10, transduces Müller cells in the Dp71-null mouse retina efficiently and specifically (2,3). Here, we use ShH10 to restore Dp71 expression in Müller cells of Dp71 deficient mouse to study molecular and functional effects of this restoration in an adult mouse displaying retinal permeability. We show that strong and specific expression of exogenous Dp71 in Müller cells leads to correct localization of Dp71 protein restoring all protein interactions in order to re-establish a proper functional BRB and retina homeostasis thus preventing retina from oedema. This study is the basis for the development of new therapeutic strategies in dealing with diseases with BRB breakdown and macular oedema such as diabetic retinopathy (DR). © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. History of gene therapy.

    PubMed

    Wirth, Thomas; Parker, Nigel; Ylä-Herttuala, Seppo

    2013-08-10

    Two decades after the initial gene therapy trials and more than 1700 approved clinical trials worldwide we not only have gained much new information and knowledge regarding gene therapy in general, but also learned to understand the concern that has persisted in society. Despite the setbacks gene therapy has faced, success stories have increasingly emerged. Examples for these are the positive recommendation for a gene therapy product (Glybera) by the EMA for approval in the European Union and the positive trials for the treatment of ADA deficiency, SCID-X1 and adrenoleukodystrophy. Nevertheless, our knowledge continues to grow and during the course of time more safety data has become available that helps us to develop better gene therapy approaches. Also, with the increased understanding of molecular medicine, we have been able to develop more specific and efficient gene transfer vectors which are now producing clinical results. In this review, we will take a historical view and highlight some of the milestones that had an important impact on the development of gene therapy. We will also discuss briefly the safety and ethical aspects of gene therapy and address some concerns that have been connected with gene therapy as an important therapeutic modality.

  5. Use of an Adult Rat Retinal Explant Model for Screening of Potential Retinal Ganglion Cell Neuroprotective Therapies

    PubMed Central

    Bull, Natalie D.; Johnson, Thomas V.; Welsapar, Guncha; DeKorver, Nicholas W.; Tomarev, Stanislav I.

    2011-01-01

    Purpose. To validate an established adult organotypic retinal explant culture system for use as an efficient medium-throughput screening tool to investigate novel retinal ganglion cell (RGC) neuroprotective therapies. Methods. Optimal culture conditions for detecting RGC neuroprotection in rat retinal explants were identified. Retinal explants were treated with various recognized, or purported, neuroprotective agents and cultured for either 4 or 7 days ex vivo. The number of cells surviving in the RGC layer (RGCL) was quantified using histologic and immunohistochemical techniques, and statistical analyses were applied to detect neuroprotective effects. Results. The ability to replicate previously reported in vivo RGC neuroprotection in retinal explants was verified by demonstrating that caspase inhibition, brain-derived neurotrophic factor treatment, and stem cell transplantation all reduced RGCL cell loss in this model. Further screening of potential neuroprotective pharmacologic agents demonstrated that betaxolol, losartan, tafluprost, and simvastatin all alleviated RGCL cell loss in retinal explants, supporting previous reports. However, treatment with brimonidine did not protect RGCL neurons from death in retinal explant cultures. Explants cultured for 4 days ex vivo proved most sensitive for detecting neuroprotection. Conclusions. The current adult rat retinal explant culture model offers advantages over other models for screening potential neuroprotective drugs, including maintenance of neurons in situ, control of environmental conditions, and dissociation from other factors such as intraocular pressure. Verification that neuroprotection by previously identified RGC-protective therapies could be replicated in adult retinal explant cultures suggests that this model could be used for efficient medium-throughput screening of novel neuroprotective therapies for retinal neurodegenerative disease. PMID:21345987

  6. Regeneration of the retina: toward stem cell therapy for degenerative retinal diseases.

    PubMed

    Jeon, Sohee; Oh, Il-Hoan

    2015-04-01

    Degenerative retinal diseases affect millions of people worldwide, which can lead to the loss of vision. However, therapeutic approaches that can reverse this process are limited. Recent efforts have allowed the possibility of the stem cell-based regeneration of retinal cells and repair of injured retinal tissues. Although the direct differentiation of pluripotent stem cells into terminally differentiated photoreceptor cells comprises one approach, a series of studies revealed the intrinsic regenerative potential of the retina using endogenous retinal stem cells. Muller glial cells, ciliary pigment epithelial cells, and retinal pigment epithelial cells are candidates for such retinal stem cells that can differentiate into multiple types of retinal cells and be integrated into injured or developing retina. In this review, we explore our current understanding of the cellular identity of these candidate retinal stem cells and their therapeutic potential for cell therapy against degenerative retinal diseases.

  7. Human gene therapy.

    PubMed

    Sandhu, J S; Keating, A; Hozumi, N

    1997-01-01

    Human gene therapy and its application for the treatment of human genetic disorders, such as cystic fibrosis, cancer, and other diseases, are discussed. Gene therapy is a technique in which a functioning gene is inserted into a human cell to correct a genetic error or to introduce a new function to the cell. Many methods, including retroviral vectors and non-viral vectors, have been developed for both ex vivo and in vivo gene transfer into cells. Vectors need to be developed that efficiently transfer genes to target cells, and promoter systems are required that regulate gene expression according to physiologic needs of the host cell. There are several safety and ethical issues related to manipulating the human genome that need to be resolved. Current gene therapy efforts focus on gene insertion into somatic cells only. Gene therapy has potential for the effective treatment of genetic disorders, and gene transfer techniques are being used for basic research, for example, in cancer, to examine the underlying mechanism of disease. There are still many technical obstacles to be overcome before human gene therapy can become a routine procedure. The current human genome project provides the sequences of a vast number of human genes, leading to the identification, characterization, and understanding of genes that are responsible for many human diseases.

  8. [Gene therapy and ethics].

    PubMed

    Müller, H; Rehmann-Sutter, C

    1995-01-10

    Gene therapy represents a new strategy to treat human disorders. It was originally conceived as a cure for severe monogenetic disorders. Since its conception, the spectrum of possible application for gene therapy has been to include the treatment of acquired diseases, such as various forms of cancer and some viral infections, most notably human immune deficiency virus (HIV) and hepatitis B virus. Since somatic gene therapy does not cause substantially new ethical problems, it has gained broad approval. This is by no means the case with germ-line gene therapy. Practically all bodies who were evaluating the related ethical aspects wanted to ban its medical application on grounds of fundamental and pragmatic considerations. In this review, practical and ethical views concerning gene therapy are summarized which were presented at the "Junitagung 1994" of the Swiss Society for Biomedical Ethics in Basle.

  9. Stem cell therapy: a novel approach for vision restoration in retinitis pigmentosa.

    PubMed

    Uy, Harvey Siy; Chan, Pik Sha; Cruz, Franz Marie

    2013-01-01

    Unfortunately, at present, degenerative retinal diseases such as retinitis pigmentosa remains untreatable. Patients with these conditions suffer progressive visual decline resulting from continuing loss of photoreceptor cells and outer nuclear layers. However, stem cell therapy is a promising approach to restore visual function in eyes with degenerative retinal diseases such as retinitis pigmentosa. Animal studies have established that pluripotent stem cells when placed in the mouse retinitis pigmentosa models have the potential not only to survive, but also to differentiate, organize into and function as photoreceptor cells. Furthermore, there is early evidence that these transplanted cells provide improved visual function. These groundbreaking studies provide proof of concept that stem cell therapy is a viable method of visual rehabilitation among eyes with retinitis pigmentosa. Further studies are required to optimize these techniques in human application. This review focuses on stem cell therapy as a new approach for vision restitution in retinitis pigmentosa.

  10. Clinical Characteristics and Current Therapies for Inherited Retinal Degenerations

    PubMed Central

    Sahel, José-Alain; Marazova, Katia; Audo, Isabelle

    2015-01-01

    Inherited retinal degenerations (IRDs) encompass a large group of clinically and genetically heterogeneous diseases that affect approximately 1 in 3000 people (>2 million people worldwide) (Bessant DA, Ali RR, Bhattacharya SS. 2001. Molecular genetics and prospects for therapy of the inherited retinal dystrophies. Curr Opin Genet Dev 11: 307–316.). IRDs may be inherited as Mendelian traits or through mitochondrial DNA, and may affect the entire retina (e.g., rod–cone dystrophy, also known as retinitis pigmentosa, cone dystrophy, cone–rod dystrophy, choroideremia, Usher syndrome, and Bardet-Bidel syndrome) or be restricted to the macula (e.g., Stargardt disease, Best disease, and Sorsby fundus dystrophy), ultimately leading to blindness. IRDs are a major cause of severe vision loss, with profound impact on patients and society. Although IRDs remain untreatable today, significant progress toward therapeutic strategies for IRDs has marked the past two decades. This progress has been based on better understanding of the pathophysiological pathways of these diseases and on technological advances. PMID:25324231

  11. Clinical characteristics and current therapies for inherited retinal degenerations.

    PubMed

    Sahel, José-Alain; Marazova, Katia; Audo, Isabelle

    2014-10-16

    Inherited retinal degenerations (IRDs) encompass a large group of clinically and genetically heterogeneous diseases that affect approximately 1 in 3000 people (>2 million people worldwide) (Bessant DA, Ali RR, Bhattacharya SS. 2001. Molecular genetics and prospects for therapy of the inherited retinal dystrophies. Curr Opin Genet Dev 11: 307-316.). IRDs may be inherited as Mendelian traits or through mitochondrial DNA, and may affect the entire retina (e.g., rod-cone dystrophy, also known as retinitis pigmentosa, cone dystrophy, cone-rod dystrophy, choroideremia, Usher syndrome, and Bardet-Bidel syndrome) or be restricted to the macula (e.g., Stargardt disease, Best disease, and Sorsby fundus dystrophy), ultimately leading to blindness. IRDs are a major cause of severe vision loss, with profound impact on patients and society. Although IRDs remain untreatable today, significant progress toward therapeutic strategies for IRDs has marked the past two decades. This progress has been based on better understanding of the pathophysiological pathways of these diseases and on technological advances. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Glaucoma, Stem Cells, and Gene Therapy: Where Are We Now?

    PubMed

    Daliri, Karim; Ljubimov, Alexander V; Hekmatimoghaddam, Seyedhossein

    2017-08-31

    Glaucoma is the second most common cause of blindness, affecting 70~80 million people around the world. The death of retinal ganglion cells (RGCs) is the main cause of blindness related to this disease. Current therapies do not provide enough protection and regeneration of RGCs. A novel opportunity for treatment of glaucoma is application of technologies related to stem cell and gene therapy. In this perspective we will thus focus on emerging approaches to glaucoma treatment including stem cells and gene therapy.

  13. Gene therapy for haemophilia.

    PubMed

    Sharma, Akshay; Easow Mathew, Manu; Sriganesh, Vasumathi; Reiss, Ulrike M

    2016-12-20

    Haemophilia is a genetic disorder characterized by spontaneous or provoked, often uncontrolled, bleeding into joints, muscles and other soft tissues. Current methods of treatment are expensive, challenging and involve regular administration of clotting factors. Gene therapy has recently been prompted as a curative treatment modality. This is an update of a published Cochrane Review. To evaluate the safety and efficacy of gene therapy for treating people with haemophilia A or B. We searched the Cochrane Cystic Fibrosis & Genetic Disorders Group's Coagulopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of last search: 18 August 2016. Eligible trials include randomised or quasi-randomised clinical trials, including controlled clinical trials comparing gene therapy (with or without standard treatment) with standard treatment (factor replacement) or other 'curative' treatment such as stem cell transplantation for individuals with haemophilia A or B of all ages who do not have inhibitors to factor VIII or IX. No trials of gene therapy for haemophilia were found. No trials of gene therapy for haemophilia were identified. No randomised or quasi-randomised clinical trials of gene therapy for haemophilia were identified. Thus, we are unable to determine the safety and efficacy of gene therapy for haemophilia. Gene therapy for haemophilia is still in its nascent stages and there is a need for well-designed clinical trials to assess the long-term feasibility, success and risks of gene therapy for people with haemophilia.

  14. Treatment of ocular disorders by gene therapy.

    PubMed

    Solinís, M Ángeles; del Pozo-Rodríguez, Ana; Apaolaza, Paola S; Rodríguez-Gascón, Alicia

    2015-09-01

    Gene therapy to treat ocular disorders is still starting, and current therapies are primarily experimental, with most human clinical trials still in research state, although beginning to show encouraging results. Currently 33 clinical trials have been approved, are in progress, or have been completed. The most promising results have been obtained in clinical trials of ocular gene therapy for Leber Congenital Amaurosis, which have prompted the study of several ocular diseases that are good candidates to be treated with gene therapy: glaucoma, age-related macular degeneration, retinitis pigmentosa, or choroideremia. The success of gene therapy relies on the efficient delivery of the genetic material to target cells, achieving optimum long-term gene expression. Although viral vectors have been widely used, their potential risk associated mainly with immunogenicity and mutagenesis has promoted the design of non-viral vectors. In this review, the main administration routes and the most studied delivery systems, viral and non-viral, for ocular gene therapy are presented. The primary ocular disease candidates to be treated with gene therapy have been also reviewed, including the genetic basis and the most relevant preclinical and clinical studies.

  15. Regulated Gene Therapy.

    PubMed

    Breger, Ludivine; Wettergren, Erika Elgstrand; Quintino, Luis; Lundberg, Cecilia

    2016-01-01

    Gene therapy represents a promising approach for the treatment of monogenic and multifactorial neurological disorders. It can be used to replace a missing gene and mutated gene or downregulate a causal gene. Despite the versatility of gene therapy, one of the main limitations lies in the irreversibility of the process: once delivered to target cells, the gene of interest is constitutively expressed and cannot be removed. Therefore, efficient, safe and long-term gene modification requires a system allowing fine control of transgene expression.Different systems have been developed over the past decades to regulate transgene expression after in vivo delivery, either at transcriptional or post-translational levels. The purpose of this chapter is to give an overview on current regulatory system used in the context of gene therapy for neurological disorders. Systems using external regulation of transgenes using antibiotics are commonly used to control either gene expression using tetracycline-controlled transcription or protein levels using destabilizing domain technology. Alternatively, specific promoters of genes that are regulated by disease mechanisms, increasing expression as the disease progresses or decreasing expression as disease regresses, are also examined. Overall, this chapter discusses advantages and drawbacks of current molecular methods for regulated gene therapy in the central nervous system.

  16. Promising and delivering gene therapies for vision loss.

    PubMed

    Carvalho, Livia S; Vandenberghe, Luk H

    2015-06-01

    The maturity in our understanding of the genetics and the pathogenesis of disease in degenerative retinal disorders has intersected in past years with a novel treatment paradigm in which a genetic intervention may lead to sustained therapeutic benefit, and in some cases even restoration of vision. Here, we review this prospect of retinal gene therapy, discuss the enabling technologies that have led to first-in-human demonstrations of efficacy and safety, and the road that led to this exciting point in time.

  17. Parkinson's disease: gene therapies.

    PubMed

    Coune, Philippe G; Schneider, Bernard L; Aebischer, Patrick

    2012-04-01

    With the recent development of effective gene delivery systems, gene therapy for the central nervous system is finding novel applications. Here, we review existing viral vectors and discuss gene therapy strategies that have been proposed for Parkinson's disease. To date, most of the clinical trials were based on viral vectors to deliver therapeutic transgenes to neurons within the basal ganglia. Initial trials used genes to relieve the major motor symptoms caused by nigrostriatal degeneration. Although these new genetic approaches still need to prove more effective than existing symptomatic treatments, there is a need for disease-modifying strategies. The investigation of the genetic factors implicated in Parkinson's disease is providing precious insights in disease pathology that, combined with innovative gene delivery systems, will hopefully offer novel opportunities for gene therapy interventions to slow down, or even halt disease progression.

  18. Gene therapy for hemophilia.

    PubMed

    Hortelano, G; Chang, P L

    2000-01-01

    Hemophilia A and B are X-linked genetic disorders caused by deficiency of the coagulation factors VIII and IX, respectively. Because of the health hazards and costs of current product replacement therapy, much effort is devoted to the development of gene therapy for these disorders. Approaches to gene therapy for the hemophilias include: ex vivo gene therapy in which cells from the intended recipients are explanted, genetically modified to secrete Factor VIII or IX, and reimplanted into the donor; in vivo gene therapy in which Factor VIII or IX encoding vectors are directly injected into the recipient; and non-autologous gene therapy in which universal cell lines engineered to secrete Factor VIII or IX are enclosed in immuno-protective devices before implantation into recipients. Research into these approaches is aided by the many murine and canine models available. While problems of achieving high and sustained levels of factor delivery, and issues related to efficacy, safety and cost are still to be resolved, progress in gene therapy for the hemophilias has been encouraging and is likely to reach human clinical trial in the foreseeable future.

  19. 76 FR 22405 - Cellular, Tissue and Gene Therapies Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... HUMAN SERVICES Food and Drug Administration Cellular, Tissue and Gene Therapies Advisory Committee... be open to the public. Name of Committee: Cellular, Tissue and Gene Therapies Advisory Committee... gene therapy products for the treatment of retinal disorders. Topics to be considered include the...

  20. Vector platforms for gene therapy of inherited retinopathies

    PubMed Central

    Trapani, Ivana; Puppo, Agostina; Auricchio, Alberto

    2014-01-01

    Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina’s compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs’ limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations. PMID:25124745

  1. Vector platforms for gene therapy of inherited retinopathies.

    PubMed

    Trapani, Ivana; Puppo, Agostina; Auricchio, Alberto

    2014-11-01

    Inherited retinopathies (IR) are common untreatable blinding conditions. Most of them are inherited as monogenic disorders, due to mutations in genes expressed in retinal photoreceptors (PR) and in retinal pigment epithelium (RPE). The retina's compatibility with gene transfer has made transduction of different retinal cell layers in small and large animal models via viral and non-viral vectors possible. The ongoing identification of novel viruses as well as modifications of existing ones based either on rational design or directed evolution have generated vector variants with improved transduction properties. Dozens of promising proofs of concept have been obtained in IR animal models with both viral and non-viral vectors, and some of them have been relayed to clinical trials. To date, recombinant vectors based on the adeno-associated virus (AAV) represent the most promising tool for retinal gene therapy, given their ability to efficiently deliver therapeutic genes to both PR and RPE and their excellent safety and efficacy profiles in humans. However, AAVs' limited cargo capacity has prevented application of the viral vector to treatments requiring transfer of genes with a coding sequence larger than 5 kb. Vectors with larger capacity, i.e. nanoparticles, adenoviral and lentiviral vectors are being exploited for gene transfer to the retina in animal models and, more recently, in humans. This review focuses on the available platforms for retinal gene therapy to fight inherited blindness, highlights their main strengths and examines the efforts to overcome some of their limitations.

  2. Gene therapy for hemophilia.

    PubMed

    Chuah, M K; Evens, H; VandenDriessche, T

    2013-06-01

    Hemophilia A and B are X-linked monogenic disorders resulting from deficiencies of factor VIII and FIX, respectively. Purified clotting factor concentrates are currently intravenously administered to treat hemophilia, but this treatment is non-curative. Therefore, gene-based therapies for hemophilia have been developed to achieve sustained high levels of clotting factor expression to correct the clinical phenotype. Over the past two decades, different types of viral and non-viral gene delivery systems have been explored for hemophilia gene therapy research with a variety of target cells, particularly hepatocytes, hematopoietic stem cells, skeletal muscle cells, and endothelial cells. Lentiviral and adeno-associated virus (AAV)-based vectors are among the most promising vectors for hemophilia gene therapy. In preclinical hemophilia A and B animal models, the bleeding phenotype was corrected with these vectors. Some of these promising preclinical results prompted clinical translation to patients suffering from a severe hemophilic phenotype. These patients receiving gene therapy with AAV vectors showed long-term expression of therapeutic FIX levels, which is a major step forwards in this field. Nevertheless, the levels were insufficient to prevent trauma or injury-induced bleeding episodes. Another challenge that remains is the possible immune destruction of gene-modified cells by effector T cells, which are directed against the AAV vector antigens. It is therefore important to continuously improve the current gene therapy approaches to ultimately establish a real cure for hemophilia.

  3. Hydroxyl PAMAM dendrimer-based gene vectors for transgene delivery to human retinal pigment epithelial cells

    NASA Astrophysics Data System (ADS)

    Mastorakos, Panagiotis; Kambhampati, Siva P.; Mishra, Manoj K.; Wu, Tony; Song, Eric; Hanes, Justin; Kannan, Rangaramanujam M.

    2015-02-01

    Ocular gene therapy holds promise for the treatment of numerous blinding disorders. Despite the significant progress in the field of viral and non-viral gene delivery to the eye, significant obstacles remain in the way of achieving high-level transgene expression without adverse effects. The retinal pigment epithelium (RPE) is involved in the pathogenesis of retinal diseases and is a key target for a number of gene-based therapeutics. In this study, we addressed the inherent drawbacks of non-viral gene vectors and combined different approaches to design an efficient and safe dendrimer-based gene-delivery platform for delivery to human RPE cells. We used hydroxyl-terminated polyamidoamine (PAMAM) dendrimers functionalized with various amounts of amine groups to achieve effective plasmid compaction. We further used triamcinolone acetonide (TA) as a nuclear localization enhancer for the dendrimer-gene complex and achieved significant improvement in cell uptake and transfection of hard-to-transfect human RPE cells. To improve colloidal stability, we further shielded the gene vector surface through incorporation of PEGylated dendrimer along with dendrimer-TA for DNA complexation. The resultant complexes showed improved stability while minimally affecting transgene delivery, thus improving the translational relevance of this platform.Ocular gene therapy holds promise for the treatment of numerous blinding disorders. Despite the significant progress in the field of viral and non-viral gene delivery to the eye, significant obstacles remain in the way of achieving high-level transgene expression without adverse effects. The retinal pigment epithelium (RPE) is involved in the pathogenesis of retinal diseases and is a key target for a number of gene-based therapeutics. In this study, we addressed the inherent drawbacks of non-viral gene vectors and combined different approaches to design an efficient and safe dendrimer-based gene-delivery platform for delivery to human RPE

  4. Course of cytomegalovirus retinitis in the era of highly active antiretroviral therapy: five-year outcomes.

    PubMed

    Jabs, Douglas A; Ahuja, Alka; Van Natta, Mark; Lyon, Alice; Srivastava, Sunil; Gangaputra, Sapna

    2010-11-01

    To describe the 5-year outcomes of patients with cytomegalovirus (CMV) retinitis and AIDS in the era of highly active antiretroviral therapy (HAART). Prospective, multicenter, observational study. A total of 503 patients with AIDS and CMV retinitis. Follow-up every 3 months with medical history, ophthalmologic examination, laboratory testing, and retinal photographs. Participants were classified as having previously diagnosed CMV retinitis and immune recovery (CD4+ T cells ≥ 100 cells/μl), previously diagnosed retinitis and immune compromise, and newly diagnosed CMV retinitis (diagnosis <45 days before enrollment). Mortality, retinitis progression (movement of the border of a CMV lesion ≥ ½ disc diameter or occurrence of a new lesion), retinal detachment, immune recovery uveitis (IRU), and visual loss (< 20/40 and ≥ 20/200). Overall mortality was 9.8 deaths/100 person-years (PY). Rates varied by group at enrollment from 3.0/100 PY for those with previously diagnosed retinitis and immune recovery to 26.1/100 PY for those with newly diagnosed retinitis. The rate of retinitis progression was 7.0/100 PY and varied from 1.4/100 PY for those with previously diagnosed retinitis and immune recovery to 28.0/100 PY for those with newly diagnosed retinitis. The rate of retinal detachment was 2.3/100 eye-years (EY) and varied from 1.2/100 EY for those with previously diagnosed retinitis and immune recovery to 4.9/100 EY for those with newly diagnosed retinitis. The rate of IRU was 1.7/100 PY and varied from 1.3/100 PY for those with previously diagnosed retinitis and immune recovery at enrollment to 3.6/100 PY for those with newly diagnosed retinitis who subsequently experienced immune recovery. The rates of visual loss to < 20/40 and to ≤ 20/200 were 7.9/100 EY and 3.4/100 EY, respectively; they varied from 6.1/100 EY and 2.7/100 EY for those with previously diagnosed retinitis and immune recovery to 11.8/100 EY and 5.1/100 EY for those with newly diagnosed

  5. Gene therapy in periodontics.

    PubMed

    Chatterjee, Anirban; Singh, Nidhi; Saluja, Mini

    2013-03-01

    GENES are made of DNA - the code of life. They are made up of two types of base pair from different number of hydrogen bonds AT, GC which can be turned into instruction. Everyone inherits genes from their parents and passes them on in turn to their children. Every person's genes are different, and the changes in sequence determine the inherited differences between each of us. Some changes, usually in a single gene, may cause serious diseases. Gene therapy is 'the use of genes as medicine'. It involves the transfer of a therapeutic or working gene copy into specific cells of an individual in order to repair a faulty gene copy. Thus it may be used to replace a faulty gene, or to introduce a new gene whose function is to cure or to favorably modify the clinical course of a condition. It has a promising era in the field of periodontics. Gene therapy has been used as a mode of tissue engineering in periodontics. The tissue engineering approach reconstructs the natural target tissue by combining four elements namely: Scaffold, signaling molecules, cells and blood supply and thus can help in the reconstruction of damaged periodontium including cementum, gingival, periodontal ligament and bone.

  6. Gene therapy for hemophilia.

    PubMed

    Ponder, Katherine P

    2006-09-01

    This review will highlight the progress achieved in the past 2 years on using gene therapy to treat hemophilia in animals and humans. There has been substantial progress in using gene therapy to treat animals with hemophilia. Novel approaches for hemophilia A in mice include expression of Factor VIII in blood cells or platelets derived from ex-vivo transduced hematopoietic stem cells, or in-vivo transfer of transposons expressing Factor VIII into endothelial cells or hepatocytes. Advances in large-animal models include the demonstration that neonatal administration of a retroviral vector expressing canine Factor VIII completely corrected hemophilia A in dogs, and that double-stranded adeno-associated virus vectors resulted in expression of Factor IX that is 28-fold that obtained using single-stranded adeno-associated virus vectors. In humans, one hemophilia B patient achieved 10% of normal activity after liver-directed gene therapy with a single-stranded adeno-associated virus vector expressing human Factor IX. Expression fell at 1 month, however, which was likely due to an immune response to the modified cells. Gene therapy has been successful in a patient with hemophilia B, but expression was unstable due to an immune response. Abrogating immune responses is the next major hurdle for achieving long-lasting gene therapy.

  7. Gene therapy for newborns.

    PubMed

    Kohn, D B; Parkman, R

    1997-07-01

    Application of gene therapy to treat genetic and infectious diseases may have several advantages if performed in newborns. Because of the minimal adverse effect of the underlying disease on cells of the newborn, the relatively small size of infants, and the large amount of future growth, gene therapy may be more successful in newborns than in older children or adults. The presence of umbilical cord blood from newborns provides a unique and susceptible target for the genetic modification of hematopoietic stem cells. In our first trial of gene therapy in newborns, we inserted a normal adenosine deaminase gene into umbilical cord blood cells of three neonates with a congenital immune deficiency. The trial demonstrated the successful transduction and engraftment of stem cells, which continue to contribute to leukocyte production more than 3 years later. A similar approach may be taken to insert genes that inhibit replication of HIV-1 into umbilical cord blood cells of HIV-1-infected neonates. Many other metabolic and infectious disorders could be treated by gene therapy during the neonatal period if prenatal diagnoses are made and the appropriate technical and regulatory requirements have been met.

  8. Distilling a Visual Network of Retinitis Pigmentosa Gene-Protein Interactions to Uncover New Disease Candidates

    PubMed Central

    Boloc, Daniel; Castillo-Lara, Sergio; Marfany, Gemma; Gonzàlez-Duarte, Roser; Abril, Josep F.

    2015-01-01

    Background Retinitis pigmentosa (RP) is a highly heterogeneous genetic visual disorder with more than 70 known causative genes, some of them shared with other non-syndromic retinal dystrophies (e.g. Leber congenital amaurosis, LCA). The identification of RP genes has increased steadily during the last decade, and the 30% of the cases that still remain unassigned will soon decrease after the advent of exome/genome sequencing. A considerable amount of genetic and functional data on single RD genes and mutations has been gathered, but a comprehensive view of the RP genes and their interacting partners is still very fragmentary. This is the main gap that needs to be filled in order to understand how mutations relate to progressive blinding disorders and devise effective therapies. Methodology We have built an RP-specific network (RPGeNet) by merging data from different sources: high-throughput data from BioGRID and STRING databases, manually curated data for interactions retrieved from iHOP, as well as interactions filtered out by syntactical parsing from up-to-date abstracts and full-text papers related to the RP research field. The paths emerging when known RP genes were used as baits over the whole interactome have been analysed, and the minimal number of connections among the RP genes and their close neighbors were distilled in order to simplify the search space. Conclusions In contrast to the analysis of single isolated genes, finding the networks linking disease genes renders powerful etiopathological insights. We here provide an interactive interface, RPGeNet, for the molecular biologist to explore the network centered on the non-syndromic and syndromic RP and LCA causative genes. By integrating tissue-specific expression levels and phenotypic data on top of that network, a more comprehensive biological view will highlight key molecular players of retinal degeneration and unveil new RP disease candidates. PMID:26267445

  9. Measurements of retinal temperature increase during photodynamic therapy for choroidal neovascularization

    NASA Astrophysics Data System (ADS)

    Chen, Hongxia; Yang, Zaifu; Gu, Ying; Li, Xiaoxia; Zhao, Youquan; Zhang, Luyong; Qiu, Haixia

    2010-11-01

    To study the risk of retinal thermal injury from 532 nm laser during photodynamic therapy (PDT) for choroidal neovascularization (CNV) by measuring the retinal temperature increase of rabbit eyes. A microthermocouple technique was developed to measure retinal temperature increase during PDT in pigmented and non-pigmented rabbit eyes. The 532 nm laser exposures were performed with 100-s duration, 2-mm spot size, and retinal irradiance ranging from 400 to 1600 mW/cm2. A K-type microthermocouple was inserted through the sclerotomy and advanced until the tip reached the retina at the posterior pole. The thermocouple was connected a computer that recorded and analyzed retinal temperature data. The results showed that the retinal temperature increase during laser exposure was proportional to retinal irradiance with a particular spot diameter, exposure duration, wavelength, and fundus pigmentation. And the measured retinal temperature increases in pigmented rabbits were a little higher than those in albino rabbits under the same radiant condition. Retinal threshold irradiance required for visible lesions at laser wavelength of 532 nm with 2.0-mm spot size and 100-s duration was 1657 mW/cm2 in albino and 1003 mW/cm2 in pigmented rabbits, respectively, corresponding to retinal temperature increase of about 8 °C and 6 °C. The measured temperatures in albino and pigmented rabbit eyes were both lower than the model predictions, especially in pigmented rabbits. Therefore, further parameter modifying should be performed to obtain accuracy prediction of retinal temperature.

  10. Genes and Mutations Causing Autosomal Dominant Retinitis Pigmentosa

    PubMed Central

    Daiger, Stephen P.; Bowne, Sara J.; Sullivan, Lori S.

    2015-01-01

    Retinitis pigmentosa (RP) has a prevalence of approximately one in 4000; 25%–30% of these cases are autosomal dominant retinitis pigmentosa (adRP). Like other forms of inherited retinal disease, adRP is exceptionally heterogeneous. Mutations in more than 25 genes are known to cause adRP, more than 1000 mutations have been reported in these genes, clinical findings are highly variable, and there is considerable overlap with other types of inherited disease. Currently, it is possible to detect disease-causing mutations in 50%–75% of adRP families in select populations. Genetic diagnosis of adRP has advantages over other forms of RP because segregation of disease in families is a useful tool for identifying and confirming potentially pathogenic variants, but there are disadvantages too. In addition to identifying the cause of disease in the remaining 25% of adRP families, a central challenge is reconciling clinical diagnosis, family history, and molecular findings in patients and families. PMID:25304133

  11. Combined intravitreal bevacizumab and photodynamic therapy for retinal angiomatous proliferation.

    PubMed

    Saito, Masaaki; Shiragami, Chieko; Shiraga, Fumio; Nagayama, Dai; Iida, Tomohiro

    2008-12-01

    To clarify the efficiency of combined therapy with intravitreal bevacizumab injections and photodynamic therapy (PDT) in patients with retinal angiomatous proliferation (RAP). Retrospective, observational, consecutive case series. We retrospectively reviewed 11 consecutive eyes with RAP (10 patients; six men, four women) treated with intravitreal bevacizumab injection and PDT. Patients ranged in age from 63 to 89 years old (average, 79 years). No patients had undergone previous treatment, and patients were followed for at least six months. PDT was applied one or two days after the intravitreal bevacizumab (1.25 mg) injection. The mean best-corrected visual acuity (BCVA) levels at baseline and one, three, and six months after treatment were 0.16, 0.27, 0.31, and 0.29, respectively. A significant improvement in the mean BCVA was observed one, three, and six months after intravitreal bevacizumab injection and PDT (P < .01). The mean improvement in BCVA six months from baseline was 2.64 lines. The BCVA at six months improved in six eyes (54.5%, improved by three lines or more) and was stable in five eyes (45.5%). No patient had a decrease in the BCVA of three or more lines during any six months. The central retinal thickness significantly decreased from 496 +/- 189 microm to 175 +/- 33 microm at six months (P < .001). No patients required retreatment during any six months. No complications such as severe vision loss, endophthalmitis, or systemic events developed. Combined intravitreal bevacizumab and PDT for RAP effectively maintained or improved VA and reduced or eliminated edema in the short-term.

  12. Hydroxyl PAMAM dendrimer-based gene vectors for transgene delivery to human retinal pigment epithelial cells†

    PubMed Central

    Mastorakos, Panagiotis; Kambhampati, Siva P.; Mishra, Manoj K.; Wu, Tony; Song, Eric; Hanes, Justin

    2016-01-01

    Ocular gene therapy holds promise for the treatment of numerous blinding disorders. Despite the significant progress in the field of viral and non-viral gene delivery to the eye, significant obstacles remain in the way of achieving high-level transgene expression without adverse effects. The retinal pigment epithelium (RPE) is involved in the pathogenesis of retinal diseases and is a key target for a number of gene-based therapeutics. In this study, we addressed the inherent drawbacks of non-viral gene vectors and combined different approaches to design an efficient and safe dendrimer-based gene-delivery platform for delivery to human RPE cells. We used hydroxyl-terminated polyamidoamine (PAMAM) dendrimers functionalized with various amounts of amine groups to achieve effective plasmid compaction. We further used triamcinolone acetonide (TA) as a nuclear localization enhancer for the dendrimer-gene complex and achieved significant improvement in cell uptake and transfection of hard-to-transfect human RPE cells. To improve colloidal stability, we further shielded the gene vector surface through incorporation of PEGylated dendrimer along with dendrimer-TA for DNA complexation. The resultant complexes showed improved stability while minimally affecting transgene delivery, thus improving the translational relevance of this platform. PMID:25213606

  13. Recombinant AAV-mediated gene transfer to the retina: gene therapy perspectives.

    PubMed

    Rolling, F

    2004-10-01

    Retinal degenerative diseases such as retinal macular degeneration and retinitis pigmentosa constitute a broad group of diseases that all share one critical feature, the progressive apoptotic loss of cells in the retina. There is currently no effective treatment available by which the course of these disorders can be modified, and visual dysfunction often progresses to total blindness. Gene therapy represents an attractive approach to treating retinal degeneration because the eye is easily accessible and allows local application of therapeutic vectors with reduced risk of systemic effects. Furthermore, transgene expression within the retina and effects of treatments may be monitored by a variety of noninvasive examinations. An increasing number of strategies for molecular treatment of retinal disease rely on recombinant adeno-associated virus (rAAV) as a therapeutic gene delivery vector. Before rAAV-mediated gene therapy for retinal degeneration becomes a reality, there are a number of important requirements that include: (1) evaluation of different rAAV serotypes, (2) screening of vectors in large animals in order to ensure that they mediate safe and long-term gene expression, (3) appropriate regulation of therapeutic gene expression, (4) evaluation of vectors carrying a therapeutic gene in relevant animal models, (5) identification of suitable patients, and finally (6) manufacture of clinical grade vector. All these steps towards gene therapy are still being explored. Outcomes of these studies will be discussed in the order in which they occur, from vector studies to preclinical assessment of the therapeutic potential of rAAV in animal models of retinal degeneration.

  14. Gene Therapy for Skin Diseases

    PubMed Central

    Gorell, Emily; Nguyen, Ngon; Lane, Alfred; Siprashvili, Zurab

    2014-01-01

    The skin possesses qualities that make it desirable for gene therapy, and studies have focused on gene therapy for multiple cutaneous diseases. Gene therapy uses a vector to introduce genetic material into cells to alter gene expression, negating a pathological process. This can be accomplished with a variety of viral vectors or nonviral administrations. Although results are promising, there are several potential pitfalls that must be addressed to improve the safety profile to make gene therapy widely available clinically. PMID:24692191

  15. Alphaviruses in Gene Therapy

    PubMed Central

    Lundstrom, Kenneth

    2015-01-01

    Alphavirus vectors present an attractive approach for gene therapy applications due to the rapid and simple recombinant virus particle production and their broad range of mammalian host cell transduction. Mainly three types of alphavirus vectors, namely naked RNA, recombinant particles and DNA/RNA layered vectors, have been subjected to preclinical studies with the goal of achieving prophylactic or therapeutic efficacy, particularly in oncology. In this context, immunization with alphavirus vectors has provided protection against challenges with tumor cells. Moreover, alphavirus intratumoral and systemic delivery has demonstrated substantial tumor regression and significant prolonged survival rates in various animal tumor models. Recent discoveries of the strong association of RNA interference and disease have accelerated gene therapy based approaches, where alphavirus-based gene delivery can play an important role. PMID:25961488

  16. Gene Therapy and Children (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Gene Therapy and Children KidsHealth > For Parents > Gene Therapy and ... by a "bad" gene. continue Two Types of Gene Therapy The two forms of gene therapy are: Somatic ...

  17. The ethics of gene therapy.

    PubMed

    Chan, Sarah; Harris, John

    2006-10-01

    Recent developments have progressed in areas of science that pertain to gene therapy and its ethical implications. This review discusses the current state of therapeutic gene technologies, including stem cell therapies and genetic modification, and identifies ethical issues of concern in relation to the science of gene therapy and its application, including the ethics of embryonic stem cell research and therapeutic cloning, the risks associated with gene therapy, and the ethics of clinical research in developing new therapeutic technologies. Additionally, ethical issues relating to genetic modification itself are considered: the significance of the human genome, the distinction between therapy and enhancement, and concerns regarding gene therapy as a eugenic practice.

  18. Progressive Outer Retinal Necrosis and Immunosuppressive Therapy in Myasthenia Gravis

    PubMed Central

    Coisy, Solène; Ebran, Jean-Marc; Milea, Dan

    2014-01-01

    Introduction Progressive outer retinal necrosis (PORN) is a rare but devastating infectious retinitis associated with varicella zoster virus (VZV) and responsible for severe visual loss. Case Report A 59-year-old man treated for generalized myasthenia with oral azathioprine and prednisone presented with severe unilateral necrotizing retinitis. Polymerase chain reaction of the aqueous and vitreous humors was diagnostic for VZV PORN. Conclusion VZV PORN is a severe potential ocular complication of immunosuppression, prompting urgent diagnosis and appropriate treatment. PMID:24926266

  19. Progressive outer retinal necrosis and immunosuppressive therapy in myasthenia gravis.

    PubMed

    Coisy, Solène; Ebran, Jean-Marc; Milea, Dan

    2014-01-01

    Progressive outer retinal necrosis (PORN) is a rare but devastating infectious retinitis associated with varicella zoster virus (VZV) and responsible for severe visual loss. A 59-year-old man treated for generalized myasthenia with oral azathioprine and prednisone presented with severe unilateral necrotizing retinitis. Polymerase chain reaction of the aqueous and vitreous humors was diagnostic for VZV PORN. VZV PORN is a severe potential ocular complication of immunosuppression, prompting urgent diagnosis and appropriate treatment.

  20. Gene therapy for mucopolysaccharidosis

    PubMed Central

    Ponder, Katherine P; Haskins, Mark E

    2012-01-01

    Mucopolysaccharidoses (MPS) are due to deficiencies in activities of lysosomal enzymes that degrade glycosaminoglycans. Some attempts at gene therapy for MPS in animal models have involved intravenous injection of vectors derived from an adeno-associated virus (AAV), adenovirus, retrovirus or a plasmid, which primarily results in expression in liver and secretion of the relevant enzyme into blood. Most vectors can correct disease in liver and spleen, although correction in other organs including the brain requires high enzyme activity in the blood. Alternative approaches are to transduce hematopoietic stem cells, or to inject a vector locally into difficult-to-reach sites such as the brain. Gene therapy holds great promise for providing a long-lasting therapeutic effect for MPS if safety issues can be resolved. PMID:17727324

  1. Dendrimer-based targeted intravitreal therapy for sustained attenuation of neuroinflammation in retinal degeneration.

    PubMed

    Iezzi, Raymond; Guru, Bharath R; Glybina, Inna V; Mishra, Manoj K; Kennedy, Alexander; Kannan, Rangaramanujam M

    2012-01-01

    Retinal neuroinflammation, mediated by activated microglia, plays a key role in the pathogenesis of photoreceptor and retinal pigment epithelial cell loss in age-related macular degeneration and retinitis pigmentosa. Targeted drug therapy for attenuation of neuroinflammation in the retina was explored using hydroxyl-terminated polyamidoamine (PAMAM) dendrimer-drug conjugate nanodevices. We show that, upon intravitreal administration, PAMAM dendrimers selectively localize within activated outer retinal microglia in two rat models of retinal degeneration, but not in the retina of healthy controls. This pathology-dependent biodistribution was exploited for drug delivery, by covalently conjugating fluocinolone acetonide to the dendrimer. The conjugate released the drug in a sustained manner over 90 days. In vivo efficacy was assessed using the Royal College of Surgeons (RCS) rat retinal degeneration model over a four-week period when peak retinal degeneration occurs. One intravitreal injection of 1 μg of FA conjugated to 7 μg of the dendrimer was able to arrest retinal degeneration, preserve photoreceptor outer nuclear cell counts, and attenuate activated microglia, for an entire month. These studies suggest that PAMAM dendrimers (with no targeting ligands) have an intrinsic ability to selectively localize in activated microglia, and can deliver drugs inside these cells for a sustained period for the treatment of retinal neuroinflammation.

  2. Perspectives of Stem Cell-Based Therapy for Age-Related Retinal Degenerative Diseases.

    PubMed

    Holan, Vladimir; Hermankova, Barbora; Kossl, Jan

    2017-03-17

    Retinal degenerative diseases, which include age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy and glaucoma, mostly affect the elderly population, and are the most common cause of decreased quality of vision or even blindness. So far, there is no satisfactory treatment protocol to prevent, stop or cure these disorders. A great hope and promise for patients suffering from retinal diseases is represented by stem cell-based therapy which could replace diseased or missing retinal cells, and support regeneration. In this respect, mesenchymal stem cells (MSCs) which can be obtained from the particular patient, and used as autologous cells, have turned out to be a promising stem cell type for treatment. Here we show that MSCs can differentiate into cells expressing markers of retinal cells, inhibit production of proinflammatory cytokines by retinal tissue and produce a number of growth and neuroprotective factors for retinal regeneration. All of these properties make MSCs a prospective cell type for cell-based therapy of age-related retinal degenerative diseases.

  3. Transposons for gene therapy!

    PubMed

    Ivics, Zoltán; Izsvák, Zsuzsanna

    2006-10-01

    Gene therapy is a promising strategy for the treatment of several inherited and acquired human diseases. Several vector platforms exist for the delivery of therapeutic nucleic acids into cells. Vectors based on viruses are very efficient at introducing gene constructs into cells, but their use has been associated with genotoxic effects of vector integration or immunological complications due to repeated administration in vivo. Non-viral vectors are easier to engineer and manufacture, but their efficient delivery into cells is a major challenge, and the lack of their chromosomal integration precludes long-term therapeutic effects. Transposable elements are non-viral gene delivery vehicles found ubiquitously in nature. Transposon-based vectors have the capacity of stable genomic integration and long-lasting expression of transgene constructs in cells. Molecular reconstruction of Sleeping Beauty, an ancient transposon in fish, represents a cornerstone in applying transposition-mediated gene delivery in vertebrate species, including humans. This review summarizes the state-of-the-art in the application of transposable elements for therapeutic gene transfer, and identifies key targets for the development of transposon-based gene vectors with enhanced efficacy and safety for human applications.

  4. [Progress on study of achromatopsia and targeted gene therapy].

    PubMed

    Dai, Xu-feng; Pang, Ji-jing

    2012-08-01

    Achromatopsia is an early onset retinal dystrophy that causes severe visual impairment. To date, four genes have been found to be implicated in achromatopsia-associated mutations: guanine nucleotide-binding protein (GNAT2), cyclic nucleotide-gated channel alpha-3 (CNGA3), cyclic nucleotide-gated channel beta-3 (CNGB3) and phosphodiesterase 6C (PDE6C). Even with early onset, the slow progress and the good responses to gene therapy in animal models render achromatopsia a very attractive candidate for human gene therapy after the successful of the Phase I clinical trials of Leber's congenital amaurosis. With the development of molecular genetics and the therapeutic gene replacement technology, the adeno-associated viral (AAV) vector-mediated gene therapy for achromatopsia in the preclinical animal experiments achieved encouraging progress in the past years. This article briefly reviews the recent research achievements of achromatopsia with gene therapy.

  5. nanosheets for gene therapy

    NASA Astrophysics Data System (ADS)

    Kou, Zhongyang; Wang, Xin; Yuan, Renshun; Chen, Huabin; Zhi, Qiaoming; Gao, Ling; Wang, Bin; Guo, Zhaoji; Xue, Xiaofeng; Cao, Wei; Guo, Liang

    2014-10-01

    A new class of two-dimensional (2D) nanomaterial, transition metal dichalcogenides (TMDCs) such as MoS2, MoSe2, WS2, and WSe2 which have fantastic physical and chemical properties, has drawn tremendous attention in different fields recently. Herein, we for the first time take advantage of the great potential of MoS2 with well-engineered surface as a novel type of 2D nanocarriers for gene delivery and therapy of cancer. In our system, positively charged MoS2-PEG-PEI is synthesized with lipoic acid-modified polyethylene glycol (LA-PEG) and branched polyethylenimine (PEI). The amino end of positively charged nanomaterials can bind to the negatively charged small interfering RNA (siRNA). After detection of physical and chemical characteristics of the nanomaterial, cell toxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Polo-like kinase 1 (PLK1) was investigated as a well-known oncogene, which was a critical regulator of cell cycle transmission at multiple levels. Through knockdown of PLK1 with siRNA carried by novel nanovector, qPCR and Western blot were used to measure the interfering efficiency; apoptosis assay was used to detect the transfection effect of PLK1. All results showed that the novel nanocarrier revealed good biocompatibility, reduced cytotoxicity, as well as high gene-carrying ability without serum interference, thus would have great potential for gene delivery and therapy.

  6. Development of gene and stem cell therapy for ocular neurodegeneration

    PubMed Central

    Zhang, Jing-Xue; Wang, Ning-Li; Lu, Qing-Jun

    2015-01-01

    Retinal degenerative diseases pose a serious threat to eye health, but there is currently no effective treatment available. Recent years have witnessed rapid development of several cutting-edge technologies, such as gene therapy, stem cell therapy, and tissue engineering. Due to the special features of ocular structure, some of these technologies have been translated into ophthalmological clinic practice with fruitful achievements, setting a good example for other fields. This paper reviews the development of the gene and stem cell therapies in ophthalmology. PMID:26086019

  7. Gene therapy in pancreatic cancer.

    PubMed

    Liu, Si-Xue; Xia, Zhong-Sheng; Zhong, Ying-Qiang

    2014-10-07

    Pancreatic cancer (PC) is a highly lethal disease and notoriously difficult to treat. Only a small proportion of PC patients are eligible for surgical resection, whilst conventional chemoradiotherapy only has a modest effect with substantial toxicity. Gene therapy has become a new widely investigated therapeutic approach for PC. This article reviews the basic rationale, gene delivery methods, therapeutic targets and developments of laboratory research and clinical trials in gene therapy of PC by searching the literature published in English using the PubMed database and analyzing clinical trials registered on the Gene Therapy Clinical Trials Worldwide website (http://www. wiley.co.uk/genmed/ clinical). Viral vectors are main gene delivery tools in gene therapy of cancer, and especially, oncolytic virus shows brighter prospect due to its tumor-targeting property. Efficient therapeutic targets for gene therapy include tumor suppressor gene p53, mutant oncogene K-ras, anti-angiogenesis gene VEGFR, suicide gene HSK-TK, cytosine deaminase and cytochrome p450, multiple cytokine genes and so on. Combining different targets or combination strategies with traditional chemoradiotherapy may be a more effective approach to improve the efficacy of cancer gene therapy. Cancer gene therapy is not yet applied in clinical practice, but basic and clinical studies have demonstrated its safety and clinical benefits. Gene therapy will be a new and promising field for the treatment of PC.

  8. Gene therapy in pancreatic cancer

    PubMed Central

    Liu, Si-Xue; Xia, Zhong-Sheng; Zhong, Ying-Qiang

    2014-01-01

    Pancreatic cancer (PC) is a highly lethal disease and notoriously difficult to treat. Only a small proportion of PC patients are eligible for surgical resection, whilst conventional chemoradiotherapy only has a modest effect with substantial toxicity. Gene therapy has become a new widely investigated therapeutic approach for PC. This article reviews the basic rationale, gene delivery methods, therapeutic targets and developments of laboratory research and clinical trials in gene therapy of PC by searching the literature published in English using the PubMed database and analyzing clinical trials registered on the Gene Therapy Clinical Trials Worldwide website (http://www. wiley.co.uk/genmed/ clinical). Viral vectors are main gene delivery tools in gene therapy of cancer, and especially, oncolytic virus shows brighter prospect due to its tumor-targeting property. Efficient therapeutic targets for gene therapy include tumor suppressor gene p53, mutant oncogene K-ras, anti-angiogenesis gene VEGFR, suicide gene HSK-TK, cytosine deaminase and cytochrome p450, multiple cytokine genes and so on. Combining different targets or combination strategies with traditional chemoradiotherapy may be a more effective approach to improve the efficacy of cancer gene therapy. Cancer gene therapy is not yet applied in clinical practice, but basic and clinical studies have demonstrated its safety and clinical benefits. Gene therapy will be a new and promising field for the treatment of PC. PMID:25309069

  9. Cardiac Gene Therapy

    PubMed Central

    Chaanine, Antoine H.; Kalman, Jill; Hajjar, Roger J.

    2010-01-01

    Heart failure is a chronic progressive disorder where frequent and recurrent hospitalizations are associated with high mortality and morbidity. The incidence and the prevalence of this disease will increase with the increase in the number of the aging population of the United States. Understanding the molecular pathology and pathophysiology of this disease will uncover novel targets and therapies that can restore the function or attenuate the damage of malfunctioning cardiomyocytes by gene therapy that becomes an interesting and a promising field for the treatment of heart failure as well as other diseases in the future. Of equal importance is developing vectors and delivery methods that can efficiently transduce the majority of the cardiomyocytes, that can offer a long term expression and that can escape the host immune response. Recombinant adeno-associated virus vectors have the potential to become a promising novel therapeutic vehicles for molecular medicine in the future. PMID:21092890

  10. Retinal vascular regeneration.

    PubMed

    Otani, Atsushi; Friedlander, Martin

    2005-01-01

    We discuss the potential use of stem cells for therapeutic angiogenesis in the treatment of retinal diseases. We demonstrate that the clinical utility of these EPC may be not limited in the treatment of ischemic retinal diseases but may also have application for the treatment of retinal degenerative disorders and for a form of cell-based gene therapy. One of the greatest potential benefits of bone marrow derived EPC therapy is the possible use of autologous grafts. Nonetheless, potential toxicities and unregulated cell growth will need to be carefully evaluated before this approach is brought to the clinics.

  11. Promising and delivering gene therapies for vision loss

    PubMed Central

    Carvalho, Livia S.; Vandenberghe, Luk H.

    2014-01-01

    The maturity in our understanding of the genetics and the pathogenesis of disease in degenerative retinal disorders has intersected in past years with a novel treatment paradigm in which a genetic intervention may lead to sustained therapeutic benefit, and in some cases even restoration of vision. Here, we review this prospect of retinal gene therapy, discuss the enabling technologies that have led to first-in-human demonstrations of efficacy and safety, and the road that led to this exciting point in time. PMID:25094052

  12. Gene therapy in keratoconus

    PubMed Central

    Farjadnia, Mahgol; Naderan, Mohammad; Mohammadpour, Mehrdad

    2015-01-01

    Keratoconus (KC) is the most common ectasia of the cornea and is a common reason for corneal transplant. Therapeutic strategies that can arrest the progression of this disease and modify the underlying pathogenesis are getting more and more popularity among scientists. Cumulating data represent strong evidence of a genetic role in the pathogenesis of KC. Different loci have been identified, and certain mutations have also been mapped for this disease. Moreover, Biophysical properties of the cornea create an appropriate candidate of this tissue for gene therapy. Immune privilege, transparency and ex vivo stability are among these properties. Recent advantage in vectors, besides the ability to modulate the corneal milieu for accepting the target gene for a longer period and fruitful translation, make a big hope for stupendous results reasonable. PMID:25709266

  13. Identical mutation in a novel retinal gene causes progressive rod-cone degeneration in dogs and retinitis pigmentosa in humans.

    PubMed

    Zangerl, Barbara; Goldstein, Orly; Philp, Alisdair R; Lindauer, Sarah J P; Pearce-Kelling, Susan E; Mullins, Robert F; Graphodatsky, Alexander S; Ripoll, Daniel; Felix, Jeanette S; Stone, Edwin M; Acland, Gregory M; Aguirre, Gustavo D

    2006-11-01

    Progressive rod-cone degeneration (prcd) is a late-onset, autosomal recessive photoreceptor degeneration of dogs and a homolog for some forms of human retinitis pigmentosa (RP). Previously, the disease-relevant interval was reduced to a 106-kb region on CFA9, and a common phenotype-specific haplotype was identified in all affected dogs from several different breeds and breed varieties. Screening of a canine retinal EST library identified partial cDNAs for novel candidate genes in the disease-relevant interval. The complete cDNA of one of these, PRCD, was cloned in dog, human, and mouse. The gene codes for a 54-amino-acid (aa) protein in dog and human and a 53-aa protein in the mouse; the first 24 aa, coded for by exon 1, are highly conserved in 14 vertebrate species. A homozygous mutation (TGC --> TAC) in the second codon shows complete concordance with the disorder in 18 different dog breeds/breed varieties tested. The same homozygous mutation was identified in a human patient from Bangladesh with autosomal recessive RP. Expression studies support the predominant expression of this gene in the retina, with equal expression in the retinal pigment epithelium, photoreceptor, and ganglion cell layers. This study provides strong evidence that a mutation in the novel gene PRCD is the cause of autosomal recessive retinal degeneration in both dogs and humans.

  14. Gene therapy rescues cone function in congenital achromatopsia.

    PubMed

    Komáromy, András M; Alexander, John J; Rowlan, Jessica S; Garcia, Monique M; Chiodo, Vince A; Kaya, Asli; Tanaka, Jacqueline C; Acland, Gregory M; Hauswirth, William W; Aguirre, Gustavo D

    2010-07-01

    The successful restoration of visual function with recombinant adeno-associated virus (rAAV)-mediated gene replacement therapy in animals and humans with an inherited disease of the retinal pigment epithelium has ushered in a new era of retinal therapeutics. For many retinal disorders, however, targeting of therapeutic vectors to mutant rods and/or cones will be required. In this study, the primary cone photoreceptor disorder achromatopsia served as the ideal translational model to develop gene therapy directed to cone photoreceptors. We demonstrate that rAAV-mediated gene replacement therapy with different forms of the human red cone opsin promoter led to the restoration of cone function and day vision in two canine models of CNGB3 achromatopsia, a neuronal channelopathy that is the most common form of achromatopsia in man. The robustness and stability of the observed treatment effect was mutation independent, but promoter and age dependent. Subretinal administration of rAAV5-hCNGB3 with a long version of the red cone opsin promoter in younger animals led to a stable therapeutic effect for at least 33 months. Our results hold promise for future clinical trials of cone-directed gene therapy in achromatopsia and other cone-specific disorders.

  15. Gene therapy rescues cone function in congenital achromatopsia

    PubMed Central

    Komáromy, András M.; Alexander, John J.; Rowlan, Jessica S.; Garcia, Monique M.; Chiodo, Vince A.; Kaya, Asli; Tanaka, Jacqueline C.; Acland, Gregory M.; Hauswirth, William W.; Aguirre, Gustavo D.

    2010-01-01

    The successful restoration of visual function with recombinant adeno-associated virus (rAAV)-mediated gene replacement therapy in animals and humans with an inherited disease of the retinal pigment epithelium has ushered in a new era of retinal therapeutics. For many retinal disorders, however, targeting of therapeutic vectors to mutant rods and/or cones will be required. In this study, the primary cone photoreceptor disorder achromatopsia served as the ideal translational model to develop gene therapy directed to cone photoreceptors. We demonstrate that rAAV-mediated gene replacement therapy with different forms of the human red cone opsin promoter led to the restoration of cone function and day vision in two canine models of CNGB3 achromatopsia, a neuronal channelopathy that is the most common form of achromatopsia in man. The robustness and stability of the observed treatment effect was mutation independent, but promoter and age dependent. Subretinal administration of rAAV5–hCNGB3 with a long version of the red cone opsin promoter in younger animals led to a stable therapeutic effect for at least 33 months. Our results hold promise for future clinical trials of cone-directed gene therapy in achromatopsia and other cone-specific disorders. PMID:20378608

  16. An audit of genetic testing in diagnosis of inherited retinal disorders: a prerequisite for gene-specific intervention.

    PubMed

    Pradhan, Monika; Hayes, Ian; Vincent, Andrea

    2009-09-01

    There has been an exponential increase in the number of genes implicated in inherited retinal disease over the last decade, but the genetic and phenotypic heterogeneity limited mutation detection. The high cost of sequencing and long turn around times meant that gene testing was not a viable option, particularly in New Zealand. Recently, advancements including development of micro-array-based mutation analysis and non-for-profit laboratories have resulted in affordable and time-efficient testing. This has enabled genetic diagnostics to become an integral component of the work-up for inherited retinal disease. Genetic testing for inherited retinal disorders was initiated via the Ocular Genetic Clinic in Auckland 2 years ago. A retrospective audit of genetic testing over this period was carried out. The results of these tests and outcomes are discussed. Thirty-five probands have undergone genetic testing for retinal disorders. This has included X-Linked Retinoschisis, Leber Congenital Amaurosis, Retinitis Pigmentosa, Albinism, Achromatopsia, Usher syndrome, Stargardt disease and Mitochondrial disease. Of these, 54% of tests (19/35) showed a rare variant or pathogenic mutation. Three couples have proceeded to investigate the options of prenatal diagnosis and/or pre-implantation genetic diagnosis. The introduction of genetic testing, largely via disease arrays, has been highly successful at clarifying disease genotype in our cohort. It is now a timely and cost-effective investigation that should be elemental to the assessment of inherited retinal disease. Genetic testing in an opportune fashion permits genetic counselling, enables families to make reproductive choices and might allow the possibility of gene therapy interventions.

  17. [Basic principles of gene therapy].

    PubMed

    Vieweg, J

    1996-09-01

    The rapid development of recombinant DNA technology and our enhanced understanding of the genetic basis of human disease has facilitated the development of new molecular therapeutic modalities, termed gene therapy. Gene therapy involves the transfer of functional genes into somatic cells and their expression in target tissues in order to replace absent genes, correct defective genes, or induce antitumoral activity in the tumor-bearing host. Currently, an increasing number of gene therapy strategies are being investigated in experimental and clinical trials. Despite substantial progress, a number of technical and logistical hurdles must still be overcome before gene therapy can be safety and effectively applied in the human patient. Since gene therapy involves complex cell processing and can be time consuming and costly, simplifications or even alternative approaches will be necessary in order to establish this therapy as suitable for clinical use. This report reviews various gene therapy strategies and gene delivery techniques currently under clinical or experimental investigation. Special emphasis is given to cytokine gene therapy using gene-modified tumor vaccines for cancer treatment.

  18. Features specific to retinal pigment epithelium cells derived from three-dimensional human embryonic stem cell cultures — a new donor for cell therapy

    PubMed Central

    Li, Zhengya; Li, Qiyou; Xu, Haiwei; Yin, Zheng Qin

    2016-01-01

    Retinal pigment epithelium (RPE) transplantation is a particularly promising treatment of retinal degenerative diseases affecting RPE-photoreceptor complex. Embryonic stem cells (ESCs) provide an abundant donor source for RPE transplantation. Herein, we studied the time-course characteristics of RPE cells derived from three-dimensional human ESCs cultures (3D-RPE). We showed that 3D-RPE cells possessed morphology, ultrastructure, gene expression profile, and functions of authentic RPE. As differentiation proceeded, 3D-RPE cells could mature gradually with decreasing proliferation but increasing functions. Besides, 3D-RPE cells could form polarized monolayer with functional tight junction and gap junction. When grafted into the subretinal space of Royal College of Surgeons rats, 3D-RPE cells were safe and efficient to rescue retinal degeneration. This study showed that 3D-RPE cells were a new donor for cell therapy of retinal degenerative diseases. PMID:27009841

  19. Human Gene Therapy: Genes without Frontiers?

    ERIC Educational Resources Information Center

    Simon, Eric J.

    2002-01-01

    Describes the latest advancements and setbacks in human gene therapy to provide reference material for biology teachers to use in their science classes. Focuses on basic concepts such as recombinant DNA technology, and provides examples of human gene therapy such as severe combined immunodeficiency syndrome, familial hypercholesterolemia, and…

  20. Human Gene Therapy: Genes without Frontiers?

    ERIC Educational Resources Information Center

    Simon, Eric J.

    2002-01-01

    Describes the latest advancements and setbacks in human gene therapy to provide reference material for biology teachers to use in their science classes. Focuses on basic concepts such as recombinant DNA technology, and provides examples of human gene therapy such as severe combined immunodeficiency syndrome, familial hypercholesterolemia, and…

  1. Gene regulation in cancer gene therapy strategies.

    PubMed

    Scanlon, Ian; Lehouritis, Panos; Niculescu-Duvaz, Ion; Marais, Richard; Springer, Caroline J

    2003-10-01

    Regulation of expression in gene therapy is considered to be a very desirable goal, preventing toxic effects and improving biological efficacy. A variety of systems have been reported in an ever widening range of applications, this paper describes these systems with specific reference to cancer gene therapy.

  2. A CTRP5 gene S163R mutation knock-in mouse model for late-onset retinal degeneration

    PubMed Central

    Chavali, Venkata R.M.; Khan, Naheed W.; Cukras, Catherine A.; Bartsch, Dirk-Uwe; Jablonski, Monica M.; Ayyagari, Radha

    2011-01-01

    Late-onset retinal macular degeneration (L-ORD) is an autosomal dominant inherited disorder caused by a single missense mutation (S163R) in the CTRP5/C1QTNF5 protein. Early phenotypic features of L-ORD include: dark adaptation abnormalities, nyctalopia, and drusen deposits in the peripheral macular region. Apart from posterior segment abnormalities, these patients also develop abnormally long anterior lens zonules. In the sixth decade of life the rod and cone function declines, accompanied by electroretinogram (ERG) abnormalities. Some patients also develop choroidal neovascularization and glaucoma. In order to understand the disease pathology and mechanisms involved in retinal dystrophy, we generated a knock-in (Ctrp5+/−) mouse model carrying the disease-associated mutation in the mouse Ctrp5/C1QTNF5 gene. These mice develop slower rod-b wave recovery consistent with early dark adaptation abnormalities, accumulation of hyperautofluorescence spots, retinal pigment epithelium abnormalities, drusen, Bruch's membrane abnormalities, loss of photoreceptors, and retinal vascular leakage. The Ctrp5+/−mice, which have most of the pathological features of age-related macular degeneration, are unique and may serve as a valuable model both to understand the molecular pathology of late-onset retinal degeneration and to evaluate therapies. PMID:21349921

  3. A CTRP5 gene S163R mutation knock-in mouse model for late-onset retinal degeneration.

    PubMed

    Chavali, Venkata R M; Khan, Naheed W; Cukras, Catherine A; Bartsch, Dirk-Uwe; Jablonski, Monica M; Ayyagari, Radha

    2011-05-15

    Late-onset retinal macular degeneration (L-ORD) is an autosomal dominant inherited disorder caused by a single missense mutation (S163R) in the CTRP5/C1QTNF5 protein. Early phenotypic features of L-ORD include: dark adaptation abnormalities, nyctalopia, and drusen deposits in the peripheral macular region. Apart from posterior segment abnormalities, these patients also develop abnormally long anterior lens zonules. In the sixth decade of life the rod and cone function declines, accompanied by electroretinogram (ERG) abnormalities. Some patients also develop choroidal neovascularization and glaucoma. In order to understand the disease pathology and mechanisms involved in retinal dystrophy, we generated a knock-in (Ctrp5(+/-)) mouse model carrying the disease-associated mutation in the mouse Ctrp5/C1QTNF5 gene. These mice develop slower rod-b wave recovery consistent with early dark adaptation abnormalities, accumulation of hyperautofluorescence spots, retinal pigment epithelium abnormalities, drusen, Bruch's membrane abnormalities, loss of photoreceptors, and retinal vascular leakage. The Ctrp5(+/-) mice, which have most of the pathological features of age-related macular degeneration, are unique and may serve as a valuable model both to understand the molecular pathology of late-onset retinal degeneration and to evaluate therapies.

  4. Retinitis Pigmentosa.

    ERIC Educational Resources Information Center

    Carr, Ronald E.

    1979-01-01

    The author describes the etiology of retinitis pigmentosa, a visual dysfunction which results from progressive loss of the retinal photoreceptors. Sections address signs and symptoms, ancillary findings, heredity, clinical diagnosis, therapy, and research. (SBH)

  5. Retinitis Pigmentosa.

    ERIC Educational Resources Information Center

    Carr, Ronald E.

    1979-01-01

    The author describes the etiology of retinitis pigmentosa, a visual dysfunction which results from progressive loss of the retinal photoreceptors. Sections address signs and symptoms, ancillary findings, heredity, clinical diagnosis, therapy, and research. (SBH)

  6. [Gene therapy. Methods and applications].

    PubMed

    Jonassen, T O; Grinde, B; Orstavik, I

    1994-04-10

    Modern techniques in molecular biology and cell biology will probably make gene therapy, i.e. therapeutic transfer of genes to the patient's cells, available for treatment of many genetic diseases, cancer, cardiovascular diseases and infectious diseases. For genetic diseases the treatment will involve the transfer of a functional copy of the defect gene. The strategy for treatment of cancer may include the transfer of genes that induce the death of cancer cells via toxic molecules, and genes that enhance the immune response to tumour cells. After several years of preclinical studies, the National Institutes of Health in the USA has, up to February 1994, approved 56 protocols for clinical trials in human gene therapy. Most of the protocols include use of viruses to aid gene delivery. This paper briefly reviews the scientific basis for gene therapy, and discusses some clinical applications of somatic gene therapy in humans.

  7. Gene therapy for psychiatric disorders.

    PubMed

    Gelfand, Yaroslav; Kaplitt, Michael G

    2013-01-01

    Gene therapy has become of increasing interest in clinical neurosurgery with the completion of numerous clinical trials for Parkinson disease, Alzheimer disease, and pediatric genetic disorders. With improved understanding of the dysfunctional circuitry mediating various psychiatric disorders, deep brain stimulation for refractory psychiatric diseases is being increasingly explored in human patients. These factors are likely to facilitate development of gene therapy for psychiatric diseases. Because delivery of gene therapy agents would require the same surgical techniques currently being employed for deep brain stimulation, neurosurgeons are likely to lead the development of this field, as has occurred in other areas of clinical gene therapy for neurologic disorders. We review the current state of gene therapy for psychiatric disorders and focus specifically on particular areas of promising research that may translate into human trials for depression, drug addiction, obsessive-compulsive disorder, and schizophrenia. Issues that are relatively unique to psychiatric gene therapy are also discussed.

  8. Localization of a new autosomal dominant retinitis pigmentosa gene on chromosome 17p screeningof candidate genes

    SciTech Connect

    Greenberg, J.; Goliath, R.; Shugart, Y.Y.

    1994-09-01

    A new gene locus for autosomal dominant retinitis pigmentosa (ADRP) on 17p has been identified in a large South African (SA) family consisting of 28 living affected individuals in 4 successive generations. This is the first ADRP gene to be reported from SA. The human recoverin (RCVN) gene, which codes for a retinal-specific protein important in recovery to the dark state after visual excitation, has been mapped to 17p13.1 and was considered as a prime candidate gene for the disorder in this family. Mutation screening (using 8 different electrophoretic conditions to resolve heteroduplexes and SSCPs) did not produce any evidence of RCVN being involved in the pathogenesis of ADRP in this SA family. In addition, a mobility shift detected within exon 1 of the RCVN gene did not track with the ADRP phenotype. RP patients from 77 SA families and 30 normal individuals are being examined to establish the frequency of this polymorphism in the SA population. Highly polymorphic markers from 17p13 are now being sought in order to establish the minimum region containing this novel ADRP-SA gene. Two additional recently described retinal-expressed cDNAs, guanylyl cyclase and pigment epithelium-derived factor, which map to 17p13.1, will be tested for tight linkage to ADRP-SA.

  9. [Gene replacement therapy in achromatopsia type 2].

    PubMed

    Mühlfriedel, R; Tanimoto, N; Seeliger, M W

    2014-03-01

    Achromatopsia is an autosomal recessive inherited retinal disease caused by a complete loss of cone photoreceptor function. About 80 % of achromatopsia patients show mutations in the alpha or beta subunit (A3 and B3) of the cGMP controlled cation channel CNG (cyclic nucleotide-gated channel) of cone photoreceptors. Homologous to the human disease, CNGA3 deficient mice reveal a loss of cone specific functionality leading to degeneration of affected cone photoreceptors. The Institute for Ophthalmic Research in Tübingen has now succeeded in curing achromatopsia ACHM2 in an animal model. In this article, we explain the recombinant adeno-associated virus-based approach in detail. Furthermore, applied non-invasive diagnostic techniques for quality and success control, ERG, SLO and OCT, are described. The success of the therapy is indicated by a restored cone photoreceptor function as well as the neuronal processing of retinal signals resulting in a specific, cone-mediated behaviour. The outstanding results derived from the animal model are the starting point for the first human translation of a gene therapy for achromatopsia in Germany.

  10. Apolipoprotein E gene polymorphisms and retinal vascular signs: The Atherosclerosis Risk in Communities (ARIC) Study

    USDA-ARS?s Scientific Manuscript database

    Our objective was to examine the association between apolipoprotein E (APOE) gene polymorphisms and retinal microvascular signs. We used a population-based, cross-sectional study. Participants from the Atherosclerosis Risk in Communities Study (n=10,036; aged 49-73 years) had retinal photographs tak...

  11. Incidence of cytomegalovirus retinitis in the era of highly active antiretroviral therapy.

    PubMed

    Sugar, Elizabeth A; Jabs, Douglas A; Ahuja, Alka; Thorne, Jennifer E; Danis, Ronald P; Meinert, Curtis L

    2012-06-01

    To estimate the incidence of cytomegalovirus (CMV) retinitis in the era of highly active antiretroviral therapy (HAART) and to characterize the factors associated with increased risk of CMV retinitis. Prospective cohort study. A total of 1600 participants with acquired immunodeficiency syndrome (AIDS) but without CMV retinitis at enrollment who completed at least 1 follow-up visit in the Longitudinal Study of the Ocular Complications of AIDS (LSOCA) were seen every 6 months to obtain disease and treatment history, ophthalmic examination, and laboratory testing. Incidence of CMV retinitis and risk factors for incident CMV retinitis were assessed. The incidence rate of CMV retinitis in individuals with AIDS was 0.36/100 person-years (PY) based upon 29 incident cases during 8134 PY of follow-up. The rate was higher for those with a CD4+ T cell count at the immediately prior visit below 50 cells/μL (3.89/100 PY, P < .01), whereas only 1 individual with a CD4+ T cell count of 50 to 99 cells/μL and 2 individuals with a CD4+ T cell count >100 cells/μL developed CMV retinitis. Having a CD4+ T cell count below 50 cells/μL at the clinical visit prior to CMV retinitis evaluation was the single most important risk factor (HR: 136, 95% CI: 30 to 605, P < .0001) for developing retinitis. Patients with AIDS, especially those with severely compromised immune systems, remain at risk for developing CMV retinitis in the HAART era, although the incidence rate is reduced from that observed in the pre-HAART era. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Gene Therapy for Autoimmune Disease.

    PubMed

    Shu, Shang-An; Wang, Jinjun; Tao, Mi-Hua; Leung, Patrick S C

    2015-10-01

    Advances in understanding the immunological and molecular basis of autoimmune diseases have made gene therapy a promising approach to treat the affected patients. Gene therapy for autoimmune diseases aims to regulate the levels of proinflammatory cytokines or molecules and the infiltration of lymphocytes to the effected sites through successful delivery and expression of therapeutic genes in appropriate cells. The ultimate goal of gene therapy is to restore and maintain the immune tolerance to the relevant autoantigens and improve clinical outcomes for patients. Here, we summarize the recent progress in identifying genes responsible for autoimmune diseases and present examples where gene therapy has been applied as treatments or prevention in autoimmune diseases both in animal models and the clinical trials. Discussion on the advantages and pitfalls of gene therapy strategies employed is provided. The intent of this review is to inspire further studies toward the development of new strategies for successful treatment of autoimmune diseases.

  13. Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success.

    PubMed

    Jacobson, Samuel G; Aleman, Tomas S; Cideciyan, Artur V; Sumaroka, Alexander; Schwartz, Sharon B; Windsor, Elizabeth A M; Traboulsi, Elias I; Heon, Elise; Pittler, Steven J; Milam, Ann H; Maguire, Albert M; Palczewski, Krzysztof; Stone, Edwin M; Bennett, Jean

    2005-04-26

    Mutations in RPE65, a gene essential to normal operation of the visual (retinoid) cycle, cause the childhood blindness known as Leber congenital amaurosis (LCA). Retinal gene therapy restores vision to blind canine and murine models of LCA. Gene therapy in blind humans with LCA from RPE65 mutations may also have potential for success but only if the retinal photoreceptor layer is intact, as in the early-disease stage-treated animals. Here, we use high-resolution in vivo microscopy to quantify photoreceptor layer thickness in the human disease to define the relationship of retinal structure to vision and determine the potential for gene therapy success. The normally cone photoreceptor-rich central retina and rod-rich regions were studied. Despite severely reduced cone vision, many RPE65-mutant retinas had near-normal central microstructure. Absent rod vision was associated with a detectable but thinned photoreceptor layer. We asked whether abnormally thinned RPE65-mutant retina with photoreceptor loss would respond to treatment. Gene therapy in Rpe65(-/-) mice at advanced-disease stages, a more faithful mimic of the humans we studied, showed success but only in animals with better-preserved photoreceptor structure. The results indicate that identifying and then targeting retinal locations with retained photoreceptors will be a prerequisite for successful gene therapy in humans with RPE65 mutations and in other retinal degenerative disorders now moving from proof-of-concept studies toward clinical trials.

  14. Gene therapy for hemophilia.

    PubMed

    Rogers, Geoffrey L; Herzog, Roland W

    2015-01-01

    Hemophilia is an X-linked inherited bleeding disorder consisting of two classifications, hemophilia A and hemophilia B, depending on the underlying mutation. Although the disease is currently treatable with intravenous delivery of replacement recombinant clotting factor, this approach represents a significant cost both monetarily and in terms of quality of life. Gene therapy is an attractive alternative approach to the treatment of hemophilia that would ideally provide life-long correction of clotting activity with a single injection. In this review, we will discuss the multitude of approaches that have been explored for the treatment of both hemophilia A and B, including both in vivo and ex vivo approaches with viral and nonviral delivery vectors.

  15. Gene therapy for hemophilia

    PubMed Central

    Rogers, Geoffrey L.; Herzog, Roland W.

    2015-01-01

    Hemophilia is an X-linked inherited bleeding disorder consisting of two classifications, hemophilia A and hemophilia B, depending on the underlying mutation. Although the disease is currently treatable with intravenous delivery of replacement recombinant clotting factor, this approach represents a significant cost both monetarily and in terms of quality of life. Gene therapy is an attractive alternative approach to the treatment of hemophilia that would ideally provide life-long correction of clotting activity with a single injection. In this review, we will discuss the multitude of approaches that have been explored for the treatment of both hemophilia A and B, including both in vivo and ex vivo approaches with viral and nonviral delivery vectors. PMID:25553466

  16. Gene therapy for deafness.

    PubMed

    Kohrman, D C; Raphael, Y

    2013-12-01

    Hearing loss is the most common sensory deficit in humans and can result from genetic, environmental or combined etiologies that prevent normal function of the cochlea, the peripheral sensory organ. Recent advances in understanding the genetic pathways that are critical for the development and maintenance of cochlear function, as well as the molecular mechanisms that underlie cell trauma and death, have provided exciting opportunities for modulating these pathways to correct genetic mutations, to enhance the endogenous protective pathways for hearing preservation and to regenerate lost sensory cells with the possibility of ameliorating hearing loss. A number of recent animal studies have used gene-based therapies in innovative ways toward realizing these goals. With further refinement, some of the protective and regenerative approaches reviewed here may become clinically applicable.

  17. Ex vivo gene therapy and vision.

    PubMed

    Gregory-Evans, Kevin; Bashar, A M A Emran; Tan, Malcolm

    2012-04-01

    Ex vivo gene therapy, a technique where genetic manipulation of cells is undertaken remotely and more safely since it is outside the body, is an emerging therapeutic strategy particularly well suited to targeting a specific organ rather than for treating a whole organism. The eye and visual pathways therefore make an attractive target for this approach. With blindness still so prevalent worldwide, new approaches to treatment would also be widely applicable and a significant advance in improving quality of life. Despite being a relatively new approach, ex vivo gene therapy has already achieved significant advances in the treatment of blindness in pre-clinical trials. In particular, advances are being achieved in corneal disease, glaucoma, retinal degeneration, stroke and multiple sclerosis through genetic re-programming of cells to replace degenerate cells and through more refined neuroprotection, modulation of inflammation and replacement of deficient protein. In this review we discuss the latest developments in ex vivo gene therapy relevant to the visual pathways and highlight the challenges that need to be overcome for progress into clinical trials.

  18. Immunotherapy and gene therapy.

    PubMed

    Simpson, Elizabeth

    2004-02-01

    The Immunotherapy and Gene Therapy meeting of the Academy of Medical Sciences reviewed the state-of-the-art and translational prospects for therapeutic interventions aimed at killing tumor cells, correcting genetic defects and developing vaccines for chronic infections. Crucial basic science concepts and information about dendritic cells, the structure and function of T-cell receptors, and manipulation of the immune response by cytokine antagonists and peptides were presented. This information underpins vaccine design and delivery, as well as attempts to immunomodulate autoimmune disease. Results from studies using anticancer DNA vaccines, which include appropriate signals for both the innate and adaptive immune response, were presented in several talks. The vaccines incorporated helper epitopes and cancer target epitopes such as immunoglobulin idiotypes (for lymphomas and myelomas), melanoma-associated antigens (for melanoma and other solid tumors) and minor histocompatibility antigens (for leukemia). The results of using vaccines employing similar principles and designed to reduce viral load in HIV/AIDS patients were also presented. The introduction of suicide genes incorporating the bacterial enzyme nitroreductase gene (ntr) targeted at tumor cells prior to administration of the prodrug CB-1954, converted by ntr into a toxic alkylating agent, was discussed against the background of clinical trials and improved suicide gene design. The introduction into hematopoietic stem cells of missing genes for the common gamma-chain, deficiency of which causes severe combined immunodeficiency (SCID), used similar retroviral transduction. The outcome of treating six SCID patients in the UK, and ten in France was successful immune reconstitution in the majority of patients, but in two of the French cases a complication of lymphoproliferative disease due to insertional mutagenesis was observed. The adoptive transfer of T-cells specific for minor histocompatibility antigens (for

  19. Gene Therapy and Children (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Gene Therapy and Children KidsHealth > For Parents > Gene Therapy ... that don't respond to conventional therapies. About Genes Our genes help make us unique. Inherited from ...

  20. Retinitis Pigmentosa Treatment with Western Medicine and Traditional Chinese Medicine Therapies

    PubMed Central

    Xu, Jian; Peng, Qinghua

    2015-01-01

    Current management of retinitis pigmentosa (RP) includes an attempt at slowing down the degenerative process through therapies that use either Western or traditional Chinese medicine (TCM). Novel therapies in Western medicine (WM) include use of tailor-made gene therapy, transplantation of stem cells, or neuroprotection treatment. TCM treatment includes two major approaches. These are orally applied herbal decoctions and acupuncture. In fact, all TCM treatments are based on the differentiation of a symptom-complex, which is the characteristic essence of TCM. Thus, diagnosed RP may be treated via the liver, the kidney, and the spleen. The principle behind these treatments is to invigorate the blood and brighten the eyes by toning up the liver and the kidney. Also treatments to cope with deficiencies in the two concepts that are unique and fundamental to TCM are considered: Qi or “vital energy” and Yin and Yang or the harmony of all the opposite elements and forces that make up existence. In particular, the Qi deficiency that results from blood stasis is addressed in these treatments. This paper also puts forward the existing problems and the prospect of the future development on integrating TCM with WM. PMID:26124961

  1. Targeting inflammation in emerging therapies for genetic retinal disease.

    PubMed

    Viringipurampeer, Ishaq A; Bashar, Abu E; Gregory-Evans, Cheryl Y; Moritz, Orson L; Gregory-Evans, Kevin

    2013-01-01

    Genetic retinal diseases such as age-related macular degeneration and monogenic diseases such as retinitis pigmentosa account for some of the commonest causes of blindness in the developed world. Diverse genetic abnormalities and environmental causes have been implicated in triggering multiple pathological mechanisms such as oxidative stress, lipofuscin deposits, neovascularisation, and programmed cell death. In recent years, inflammation has also been highlighted although whether inflammatory mediators play a central role in pathogenesis or a more minor secondary role has yet to be established. Despite this, numerous interventional studies, particularly targeting the complement system, are underway with the promise of novel therapeutic strategies for these important blinding conditions.

  2. Targeting Inflammation in Emerging Therapies for Genetic Retinal Disease

    PubMed Central

    Viringipurampeer, Ishaq A.; Bashar, Abu E.; Gregory-Evans, Cheryl Y.; Moritz, Orson L.; Gregory-Evans, Kevin

    2013-01-01

    Genetic retinal diseases such as age-related macular degeneration and monogenic diseases such as retinitis pigmentosa account for some of the commonest causes of blindness in the developed world. Diverse genetic abnormalities and environmental causes have been implicated in triggering multiple pathological mechanisms such as oxidative stress, lipofuscin deposits, neovascularisation, and programmed cell death. In recent years, inflammation has also been highlighted although whether inflammatory mediators play a central role in pathogenesis or a more minor secondary role has yet to be established. Despite this, numerous interventional studies, particularly targeting the complement system, are underway with the promise of novel therapeutic strategies for these important blinding conditions. PMID:23509666

  3. Gene therapy for malignant glioma.

    PubMed

    Okura, Hidehiro; Smith, Christian A; Rutka, James T

    2014-01-01

    Glioblastoma multiforme (GBM) is the most frequent and devastating primary brain tumor in adults. Despite current treatment modalities, such as surgical resection followed by chemotherapy and radiotherapy, only modest improvements in median survival have been achieved. Frequent recurrence and invasiveness of GBM are likely due to the resistance of glioma stem cells to conventional treatments; therefore, novel alternative treatment strategies are desperately needed. Recent advancements in molecular biology and gene technology have provided attractive novel treatment possibilities for patients with GBM. Gene therapy is defined as a technology that aims to modify the genetic complement of cells to obtain therapeutic benefit. To date, gene therapy for the treatment of GBM has demonstrated anti-tumor efficacy in pre-clinical studies and promising safety profiles in clinical studies. However, while this approach is obviously promising, concerns still exist regarding issues associated with transduction efficiency, viral delivery, the pathologic response of the brain, and treatment efficacy. Tumor development and progression involve alterations in a wide spectrum of genes, therefore a variety of gene therapy approaches for GBM have been proposed. Improved viral vectors are being evaluated, and the potential use of gene therapy alone or in synergy with other treatments against GBM are being studied. In this review, we will discuss the most commonly studied gene therapy approaches for the treatment of GBM in preclinical and clinical studies including: prodrug/suicide gene therapy; oncolytic gene therapy; cytokine mediated gene therapy; and tumor suppressor gene therapy. In addition, we review the principles and mechanisms of current gene therapy strategies as well as advantages and disadvantages of each.

  4. A case of atypical progressive outer retinal necrosis after highly active antiretroviral therapy.

    PubMed

    Woo, Se Joon; Yu, Hyeong Gon; Chung, Hum

    2004-06-01

    This is a report of an atypical case of progressive outer retinal necrosis (PORN) and the effect of highly active antiretroviral therapy (HAART) on the clinical course of viral retinitis in an acquired immunodeficiency syndrome (AIDS) patient. A 22-year-old male patient infected with human immunodeficiency virus (HIV) presented with unilaterally reduced visual acuity and a dense cataract. After cataract extraction, retinal lesions involving the peripheral and macular areas were found with perivascular sparing and the mud-cracked, characteristic appearance of PORN. He was diagnosed as having PORN based on clinical features and was given combined antiviral treatment. With concurrent HAART, the retinal lesions regressed, with the regression being accelerated by further treatment with intravenous acyclovir and ganciclovir. This case suggests that HAART may change the clinical course of PORN in AIDS patients by improving host immunity. PORN should be included in the differential diagnosis of acute unilateral cataract in AIDS patients.

  5. Retinal Diseases Caused by Mutations in Genes Not Specifically Associated with the Clinical Diagnosis.

    PubMed

    Wang, Xia; Feng, Yanming; Li, Jianli; Zhang, Wei; Wang, Jing; Lewis, Richard A; Wong, Lee-Jun

    2016-01-01

    When seeking a confirmed molecular diagnosis in the research setting, patients with one descriptive diagnosis of retinal disease could carry pathogenic variants in genes not specifically associated with that description. However, this event has not been evaluated systematically in clinical diagnostic laboratories that validate fully all target genes to minimize false negatives/positives. We performed targeted next-generation sequencing analysis on 207 ocular disease-related genes for 42 patients whose DNA had been tested negative for disease-specific panels of genes known to be associated with retinitis pigmentosa, Leber congenital amaurosis, or exudative vitreoretinopathy. Pathogenic variants, including single nucleotide variations and copy number variations, were identified in 9 patients, including 6 with variants in syndromic retinal disease genes and 3 whose molecular diagnosis could not be distinguished easily from their submitted clinical diagnosis, accounting for 21% (9/42) of the unsolved cases. Our study underscores the clinical and genetic heterogeneity of retinal disorders and provides valuable reference to estimate the fraction of clinical samples whose retinal disorders could be explained by genes not specifically associated with the corresponding clinical diagnosis. Our data suggest that sequencing a larger set of retinal disorder related genes can increase the molecular diagnostic yield, especially for clinically hard-to-distinguish cases.

  6. Retinal Diseases Caused by Mutations in Genes Not Specifically Associated with the Clinical Diagnosis

    PubMed Central

    Feng, Yanming; Li, Jianli; Zhang, Wei; Wang, Jing; Lewis, Richard A.; Wong, Lee-Jun

    2016-01-01

    Purpose When seeking a confirmed molecular diagnosis in the research setting, patients with one descriptive diagnosis of retinal disease could carry pathogenic variants in genes not specifically associated with that description. However, this event has not been evaluated systematically in clinical diagnostic laboratories that validate fully all target genes to minimize false negatives/positives. Methods We performed targeted next-generation sequencing analysis on 207 ocular disease-related genes for 42 patients whose DNA had been tested negative for disease-specific panels of genes known to be associated with retinitis pigmentosa, Leber congenital amaurosis, or exudative vitreoretinopathy. Results Pathogenic variants, including single nucleotide variations and copy number variations, were identified in 9 patients, including 6 with variants in syndromic retinal disease genes and 3 whose molecular diagnosis could not be distinguished easily from their submitted clinical diagnosis, accounting for 21% (9/42) of the unsolved cases. Conclusion Our study underscores the clinical and genetic heterogeneity of retinal disorders and provides valuable reference to estimate the fraction of clinical samples whose retinal disorders could be explained by genes not specifically associated with the corresponding clinical diagnosis. Our data suggest that sequencing a larger set of retinal disorder related genes can increase the molecular diagnostic yield, especially for clinically hard-to-distinguish cases. PMID:27788217

  7. Retinal Changes Induced by Heavy Particles: A New Therapy Modality

    DTIC Science & Technology

    1975-11-01

    time. The changes in this x-ray series were erythema and edema of the lids, conjunctivitis, and an iritis . A chronic purulent lacrimatlon was...radiation produced edema, iritis , and cloud- ing of the vitreous within 24 hours without a retinal lesion. The nature of the lesions produced by the

  8. Inherited retinal diseases in dogs: advances in gene/mutation discovery

    PubMed Central

    Miyadera, Keiko

    2015-01-01

    1. Inherited retinal diseases (RDs) are vision-threatening conditions affecting humans as well as many domestic animals. Through many years of clinical studies of the domestic dog population, a wide array of RDs has been phenotypically characterized. Extensive effort to map the causative gene and to identify the underlying mutation followed. Through candidate gene, linkage analysis, genome-wide association studies, and more recently, by means of next-generation sequencing, as many as 31 mutations in 24 genes have been identified as the underlying cause for canine RDs. Most of these genes have been associated with human RDs providing opportunities to study their roles in the disease pathogenesis and in normal visual function. The canine model has also contributed in developing new treatments such as gene therapy which has been clinically applied to human patients. Meanwhile, with increasing knowledge of the molecular architecture of RDs in different subpopulations of dogs, the conventional understanding of RDs as a simple monogenic disease is beginning to change. Emerging evidence of modifiers that alters the disease outcome is complicating the interpretation of DNA tests. In this review, advances in the gene/mutation discovery approaches and the emerging genetic complexity of canine RDs are discussed. PMID:26120276

  9. Inherited retinal diseases in dogs: advances in gene/mutation discovery.

    PubMed

    Miyadera, Keiko

    1. Inherited retinal diseases (RDs) are vision-threatening conditions affecting humans as well as many domestic animals. Through many years of clinical studies of the domestic dog population, a wide array of RDs has been phenotypically characterized. Extensive effort to map the causative gene and to identify the underlying mutation followed. Through candidate gene, linkage analysis, genome-wide association studies, and more recently, by means of next-generation sequencing, as many as 31 mutations in 24 genes have been identified as the underlying cause for canine RDs. Most of these genes have been associated with human RDs providing opportunities to study their roles in the disease pathogenesis and in normal visual function. The canine model has also contributed in developing new treatments such as gene therapy which has been clinically applied to human patients. Meanwhile, with increasing knowledge of the molecular architecture of RDs in different subpopulations of dogs, the conventional understanding of RDs as a simple monogenic disease is beginning to change. Emerging evidence of modifiers that alters the disease outcome is complicating the interpretation of DNA tests. In this review, advances in the gene/mutation discovery approaches and the emerging genetic complexity of canine RDs are discussed.

  10. Stem cell-based therapeutic applications in retinal degenerative diseases

    PubMed Central

    Huang, Yiming; Enzmann, Volker; Ildstad, Suzanne T.

    2012-01-01

    Retinal degenerative diseases that target photoreceptors or the adjacent retinal pigment epithelium (RPE) affect millions of people worldwide. Retinal degeneration (RD) is found in many different forms of retinal diseases including retinitis pigmentosa (RP), age-related macular degeneration (AMD), diabetic retinopathy, cataracts, and glaucoma. Effective treatment for retinal degeneration has been widely investigated. Gene-replacement therapy has been shown to improve visual function in inherited retinal disease. However, this treatment was less effective with advanced disease. Stem cell-based therapy is being pursued as a potential alternative approach in the treatment of retinal degenerative diseases. In this review, we will focus on stem cell-based therapies in the pipeline and summarize progress in treatment of retinal degenerative disease. PMID:20859770

  11. Gene therapy in metachromatic leukodystrophy.

    PubMed

    Sevin, C; Cartier-Lacave, N; Aubourg, P

    2009-01-01

    Metachromatic leukodystrophy (MLD) is a lysosomal storage disease caused by deficiency of the lysosomal enzyme arylsulfatase A. Deficiency of this enzyme results in intralysosomal storage of sphingolipid cerebroside 3-sulfates (sulfatides), which are abundant in myelin and neurons. A pathological hallmark of MLD is demyelination and neurodegeneration, causing various and ultimately lethal neurological symptoms. This review discusses the potential therapeutic application of hematopoietic stem cell gene therapy and intracerebral gene transfer (brain gene therapy) in patients with MLD.

  12. Comparative gene expression study and pathway analysis of the human iris- and the retinal pigment epithelium

    PubMed Central

    ten Brink, Jacoline B.; Moerland, Perry D.; Heine, Vivi M.; Bergen, Arthur A.

    2017-01-01

    Background The retinal pigment epithelium (RPE) is a neural monolayer lining the back of the eye. Degeneration of the RPE leads to severe vision loss in, so far incurable, diseases such as age-related macular degeneration and some forms of retinitis pigmentosa. A promising future replacement therapy may be autologous iris epithelial cell transdifferentiation into RPE in vitro and, subsequently, transplantation. In this study we compared the gene expression profiles of the iris epithelium (IE) and the RPE. Methods We collected both primary RPE- and IE cells from 5 freshly frozen human donor eyes, using respectively laser dissection microscopy and excision. We performed whole-genome expression profiling using 44k Agilent human microarrays. We investigated the gene expression profiles on both gene and functional network level, using R and the knowledge database Ingenuity. Results The major molecular pathways related to the RPE and IE were quite similar and yielded basic neuro-epithelial cell functions. Nonetheless, we also found major specific differences: For example, genes and molecular pathways, related to the visual cycle and retinol biosynthesis are significantly higher expressed in the RPE than in the IE. Interestingly, Wnt and aryl hydrocarbon receptor (AhR-) signaling pathways are much higher expressed in the IE than in the RPE, suggesting, respectively, a possible pluripotent and high detoxification state of the IE. Conclusions This study provides a valuation of the similarities and differences between the expression profiles of the RPE and IE. Our data combined with that of the literature, represent a most comprehensive perspective on transcriptional variation, which may support future research in the development of therapeutic transplantation of IE. PMID:28827822

  13. Comparative gene expression study and pathway analysis of the human iris- and the retinal pigment epithelium.

    PubMed

    Bennis, Anna; Ten Brink, Jacoline B; Moerland, Perry D; Heine, Vivi M; Bergen, Arthur A

    2017-01-01

    The retinal pigment epithelium (RPE) is a neural monolayer lining the back of the eye. Degeneration of the RPE leads to severe vision loss in, so far incurable, diseases such as age-related macular degeneration and some forms of retinitis pigmentosa. A promising future replacement therapy may be autologous iris epithelial cell transdifferentiation into RPE in vitro and, subsequently, transplantation. In this study we compared the gene expression profiles of the iris epithelium (IE) and the RPE. We collected both primary RPE- and IE cells from 5 freshly frozen human donor eyes, using respectively laser dissection microscopy and excision. We performed whole-genome expression profiling using 44k Agilent human microarrays. We investigated the gene expression profiles on both gene and functional network level, using R and the knowledge database Ingenuity. The major molecular pathways related to the RPE and IE were quite similar and yielded basic neuro-epithelial cell functions. Nonetheless, we also found major specific differences: For example, genes and molecular pathways, related to the visual cycle and retinol biosynthesis are significantly higher expressed in the RPE than in the IE. Interestingly, Wnt and aryl hydrocarbon receptor (AhR-) signaling pathways are much higher expressed in the IE than in the RPE, suggesting, respectively, a possible pluripotent and high detoxification state of the IE. This study provides a valuation of the similarities and differences between the expression profiles of the RPE and IE. Our data combined with that of the literature, represent a most comprehensive perspective on transcriptional variation, which may support future research in the development of therapeutic transplantation of IE.

  14. Co-culture of Retinal and Endothelial Cells Results in the Modulation of Genes Critical to Retinal Neovascularization.

    PubMed

    Kumar, Ravindra; Harris-Hooker, Sandra; Kumar, Ritesh; Sanford, Gary

    2011-11-23

    Neovascularization (angiogenesis) is a multistep process, controlled by opposing regulatory factors, which plays a crucial role in several ocular diseases. It often results in vitreous hemorrhage, retinal detachment, neovascularization glaucoma and subsequent vision loss. Hypoxia is considered to be one of the key factors to trigger angiogenesis by inducing angiogenic factors (like VEGF) and their receptors mediated by hypoxia inducible factor-1 (HIF-1α) a critical transcriptional factor. Another factor, nuclear factor kappa B (NFκB) also regulates many of the genes required for neovascularization, and can also be activated by hypoxia. The aim of this study was to elucidate the mechanism of interaction between HRPC and HUVEC that modulates a neovascularization response. Human retinal progenitor cells (HRPC) and human umbilical vein endothelial cells (HUVEC) were cultured/co-cultured under normoxia (control) (20% O2) or hypoxia (1% O2) condition for 24 hr. Controls were monolayer cultures of each cell type maintained alone. We examined the secretion of VEGF by ELISA and influence of conditioned media on blood vessel growth (capillary-like structures) via an angiogenesis assay. Total RNA and protein were extracted from the HRPC and HUVEC (cultured and co-cultured) and analyzed for the expression of VEGF, VEGFR-2, NFκB and HIF-1α by RT-PCR and Western blotting. The cellular localization of NFκB and HIF-1α were studied by immunofluorescence and Western blotting. We found that hypoxia increased exogenous VEGF expression 4-fold in HRPC with a further 2-fold increase when cultured with HUVEC. Additionally, we found that hypoxia induced the expression of the VEGF receptor (VEGFR-2) for HRPC co-cultured with HUVEC. Hypoxia treatment significantly enhanced (8- to 10-fold higher than normoxia controls) VEGF secretion into media whether cells were cultured alone or in a co-culture. Also, hypoxia was found to result in a 3- and 2-fold increase in NFκB and HIF-1α m

  15. Available Evidence on Leber Congenital Amaurosis and Gene Therapy.

    PubMed

    Alkharashi, Maan; Fulton, Anne B

    2017-01-01

    Leber congenital amaurosis (LCA) is a group of severe inherited retinal dystrophies that lead to early childhood blindness. In the last decade, interest in LCA has increased as advances in genetics have been applied to better identify, classify, and treat LCA. To date, 23 LCA genes have been identified. Gene replacement in the RPE65 form of LCA represents a major advance in treatment, although limitations have been recognized. In this article, we review the clinical and genetic features of LCA and evaluate the evidence available for gene therapy in RPE65 disease.

  16. Gene therapy: progress and predictions.

    PubMed

    Collins, Mary; Thrasher, Adrian

    2015-12-22

    The first clinical gene delivery, which involved insertion of a marker gene into lymphocytes from cancer patients, was published 25 years ago. In this review, we describe progress since then in gene therapy. Patients with some inherited single-gene defects can now be treated with their own bone marrow stem cells that have been engineered with a viral vector carrying the missing gene. Patients with inherited retinopathies and haemophilia B can also be treated by local or systemic injection of viral vectors. There are also a number of promising gene therapy approaches for cancer and infectious disease. We predict that the next 25 years will see improvements in safety, efficacy and manufacture of gene delivery vectors and introduction of gene-editing technologies to the clinic. Gene delivery may also prove a cost-effective method for the delivery of biological medicines. © 2015 The Authors.

  17. Hypoxia-Inducible Factor-1α Target Genes Contribute to Retinal Neuroprotection

    PubMed Central

    Cheng, Lin; Yu, Honghua; Yan, Naihong; Lai, Kunbei; Xiang, Mengqing

    2017-01-01

    Hypoxia-inducible factor (HIF) is a transcription factor that facilitates cellular adaptation to hypoxia and ischemia. Long-standing evidence suggests that one isotype of HIF, HIF-1α, is involved in the pathogenesis of various solid tumors and cardiac diseases. However, the role of HIF-1α in retina remains poorly understood. HIF-1α has been recognized as neuroprotective in cerebral ischemia in the past two decades. Additionally, an increasing number of studies has shown that HIF-1α and its target genes contribute to retinal neuroprotection. This review will focus on recent advances in the studies of HIF-1α and its target genes that contribute to retinal neuroprotection. A thorough understanding of the function of HIF-1α and its target genes may lead to identification of novel therapeutic targets for treating degenerative retinal diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal vein occlusions. PMID:28289375

  18. Genomic Approaches For the Discovery of Genes Mutated in Inherited Retinal Degeneration

    PubMed Central

    Siemiatkowska, Anna M.; Collin, Rob W.J.; den Hollander, Anneke I.; Cremers, Frans P.M.

    2014-01-01

    In view of their high degree of genetic heterogeneity, inherited retinal diseases (IRDs) pose a significant challenge for identifying novel genetic causes. Thus far, more than 200 genes have been found to be mutated in IRDs, which together contain causal variants in >80% of the cases. Accurate genetic diagnostics is particularly important for isolated cases, in which X-linked and de novo autosomal dominant variants are not uncommon. In addition, new gene- or mutation-specific therapies are emerging, underlining the importance of identifying causative mutations in each individual. Sanger sequencing of selected genes followed by cost-effective targeted next-generation sequencing (NGS) can identify defects in known IRD-associated genes in the majority of the cases. Exome NGS in combination with genetic linkage or homozygosity mapping studies can aid the identification of the remaining causal genes. As these are thought to be mutated in <1% of the cases, validation through functional modeling in, for example, zebrafish and/or replication through the genotyping of large patient cohorts is required. In the near future, whole genome NGS in combination with transcriptome NGS may reveal mutations that are currently hidden in the noncoding regions of the human genome. PMID:24939053

  19. [Basic principles and clinical application of retinal laser therapy].

    PubMed

    Framme, C; Roider, J; Brinkmann, R; Birngruber, R; Gabel, V-P

    2008-04-01

    The scientific background of laser photocoagulation of the ocular fundus was studied extensively by several investigators in the 1970 s and 1980 s. The basic principles were successfully resolved during that time and clinical consequences for proper application of the laser photocoagulation for various diseases were deduced. The present paper gives an overview about the physical basics of laser-tissue interactions during and after retinal laser treatment and the particular laser strategies in the treatment of different retinal diseases. Thus, it addresses the issue of the impact on tissue of laser parameters as wavelength, spot size, pulse duration and laser power. Additionally, the different biological tissue reactions after laser treatment are presented, such as, e. g., for retinopexia or macular treatments as well as for diabetic retinopathies. Specific laser strategies such as the selective laser treatment of the RPE (SRT) or the transpupillary thermotherapy (TTT) are presented and discussed.

  20. Anti-VEGF Therapy for Retinal Vein Occlusions.

    PubMed

    Campa, Claudio; Alivernini, Giuseppe; Bolletta, Elena; Parodi, Maurizio Battaglia; Perri, Paolo

    2016-01-01

    Retinal vein occlusion (RVO) is the second most common cause of visual loss in the Western World. RVO is usually classified into branch RVO (BRVO) and central RVO (CRVO) according to the anatomical site of the vascular occlusion. The pathogenesis of RVO is not yet fully understood, however an important event is the intraluminal thrombus formation, which is usually secondary to several conditions such as hypertension, hyperlipidemia, diabetes and thrombophilia. The blockage of venous circulation causes an elevation of intraluminal pressure in the capillaries, leading to hemorrhages and leakage of fluid within the retina, increase of interstitial pressure and a consequent reduction of retinal perfusion. Ischemia may develop resulting in secretion of vascular endothelial growth factor (VEGF) that causes further vascular leakage and retinal oedema. VEGF has therefore a leading role in RVO pathogenesis and symptoms. As a consequence use of anti-VEGF agents by intravitreal injections has become very common with the aim to improve the clinical outcomes in these patients. Currently 2 anti-VEGF agents (ranimizumab and aflibercept) have been FDA (Food and Drug Administration) and EMA (European Medicine Agency) approved for the treatment of RVO, while another VEGF inhibitor (bevacizumab) is often used "off-label" in clinical practice. Many treatment regimens have been suggested in the clinical trials with these drugs, as monthly injections or injections when needed, however the ideal regimen has not been defined yet. We conducted a systematic review searching MEDLINE for the following terms: retinal vein occlusion, ranibizumab, bevacizumab, aflibercept, vascular endothelial growth factor, macular oedema. Data were extracted by one author (AG and BE) and checked by a second (BPM, CC). Aim of this article was to review available data for each drug, focusing on their efficacy and safety trying to compare their advantages and limits.

  1. Gene Therapy of Inherited Retinopathies: A Long and Successful Road from Viral Vectors to Patients

    PubMed Central

    Colella, Pasqualina

    2012-01-01

    Abstract Inherited retinopathies (IRs) are common and untreatable blinding conditions inherited mostly as monogenic due to mutations in genes expressed in retinal photoreceptors (PRs) and in retinal pigment epithelium (RPE). Over the last two decades, the retina has emerged as one of the most favorable target tissues for gene therapy given its small size and its enclosed and immune-privileged environment. Different types of viral vectors have been developed, especially those based on the adeno-associated virus (AAV), which efficiently deliver therapeutic genes to PRs or RPE upon subretinal injections. Dozens of successful proofs of concept of the efficacy of gene therapy for recessive and dominant IRs have been generated in small and large models that have paved the way to the first clinical trials using AAV in patients with Leber congenital amaurosis, a severe form of childhood blindness. The results from these initial trials suggest that retinal gene therapy with AAV is safe in humans, that vision can be improved in patients that have suffered from severe impairment of visual function, in some cases for decades, and that readministration of AAV to the subretinal space is feasible, effective, and safe. However, none of the trials could match the levels of efficacy of gene therapy observed in a dog model of the disease, suggesting that there is room for improvement. In conclusion, these results bode well for further testing of AAV-mediated retinal gene therapy in patients with other monogenic and complex forms of blindness. PMID:22734691

  2. Gene therapy of inherited retinopathies: a long and successful road from viral vectors to patients.

    PubMed

    Colella, Pasqualina; Auricchio, Alberto

    2012-08-01

    Inherited retinopathies (IRs) are common and untreatable blinding conditions inherited mostly as monogenic due to mutations in genes expressed in retinal photoreceptors (PRs) and in retinal pigment epithelium (RPE). Over the last two decades, the retina has emerged as one of the most favorable target tissues for gene therapy given its small size and its enclosed and immune-privileged environment. Different types of viral vectors have been developed, especially those based on the adeno-associated virus (AAV), which efficiently deliver therapeutic genes to PRs or RPE upon subretinal injections. Dozens of successful proofs of concept of the efficacy of gene therapy for recessive and dominant IRs have been generated in small and large models that have paved the way to the first clinical trials using AAV in patients with Leber congenital amaurosis, a severe form of childhood blindness. The results from these initial trials suggest that retinal gene therapy with AAV is safe in humans, that vision can be improved in patients that have suffered from severe impairment of visual function, in some cases for decades, and that readministration of AAV to the subretinal space is feasible, effective, and safe. However, none of the trials could match the levels of efficacy of gene therapy observed in a dog model of the disease, suggesting that there is room for improvement. In conclusion, these results bode well for further testing of AAV-mediated retinal gene therapy in patients with other monogenic and complex forms of blindness.

  3. Gene therapy for the eye focus on mutation-independent approaches.

    PubMed

    Dalkara, Deniz; Duebel, Jens; Sahel, José-Alain

    2015-02-01

    This review will discuss retinal gene therapy strategies with a focus on mutation-independent approaches to treat a large number of patients without knowledge of the mutant gene. These approaches rely on the secretion of neurotrophic factors to slow down retinal degeneration and the use of optogenetics to restore vision in late-stage disease. Success in clinical application of adeno-associated virus (AAV)-mediated gene therapy for Leber's congenital amaurosis established the feasibility of retinal gene therapy. More clinical trials are currently on their way for recessive diseases with known mutations. However, the genetic and mechanistic diversity of the retinal diseases presents an enormous obstacle for the development of gene therapies tailored to each patient-specific mutation. To extend gene therapy's promise to a large number of patients, evidence suggests retina-specific trophic factors, such as rod-derived cone viability factor, can be used to slow down loss of cone cells responsible for our high acuity vision. In parallel, it has been shown that microbial opsins are able to restore light sensitivity when expressed in blind retinas. Recent findings imply that using the viral technology that has been demonstrated as well tolerated in patients, there are opportunities to develop widely applicable gene therapeutic interventions in clinical ophthalmology.

  4. Gene therapy for Leber congenital amaurosis: advances and future directions.

    PubMed

    Hufnagel, Robert B; Ahmed, Zubair M; Corrêa, Zélia M; Sisk, Robert A

    2012-08-01

    Leber congenital amaurosis (LCA) is a congenital retinal dystrophy that results in significant and often severe vision loss at an early age. Comprehensive analysis of the genetic mutations and phenotypic correlations in LCA patients has allowed for significant improvements in understanding molecular pathways of photoreceptor degeneration and dysfunction. The purpose of this article is to review the literature on the subject of retinal gene therapy for LCA, including historical descriptions, preclinical animal studies, and human clinical trials. A literature search of peer-reviewed and indexed publications from 1996-2011 using the PubMed search engine was performed. Key terms included "Leber congenital amaurosis", LCA, RPE65, "cone-rod dystrophy", "gene therapy", and "human trials" in various combinations. Seminal articles prior to 1996 were selected from primary sources and reviews from the initial search. Articles were chosen based on pertinence to clinical, genetic, and therapeutic topics reviewed in this manuscript. Fundus photographs from LCA patients were obtained retrospectively from the clinical practice of one of the authors (R.A.S). Herein, we reviewed the literature on LCA as a genetic disease, the results of human gene therapy trials to date, and possible future directions towards treating inherited retinal diseases at the genetic level. Original descriptions of LCA by Theodor Leber and subsequent research demonstrate the severity of this disease with early-onset blindness. Discoveries of the causative heritable mutations revealed genes and protein products involved in photoreceptor development and visual transduction. Animal models have provided a means to test novel therapeutic strategies, namely gene therapy. Stemming from these experiments, three independent clinical trials tested the safety of subretinal delivery of viral gene therapy to patients with mutations in the RPE65 gene. More recently, efficacy studies have been conducted with encouraging

  5. Gene Therapy for Infectious Diseases

    PubMed Central

    Bunnell, Bruce A.; Morgan, Richard A.

    1998-01-01

    Gene therapy is being investigated as an alternative treatment for a wide range of infectious diseases that are not amenable to standard clinical management. Approaches to gene therapy for infectious diseases can be divided into three broad categories: (i) gene therapies based on nucleic acid moieties, including antisense DNA or RNA, RNA decoys, and catalytic RNA moieties (ribozymes); (ii) protein approaches such as transdominant negative proteins and single-chain antibodies; and (iii) immunotherapeutic approaches involving genetic vaccines or pathogen-specific lymphocytes. It is further possible that combinations of the aforementioned approaches will be used simultaneously to inhibit multiple stages of the life cycle of the infectious agent. PMID:9457428

  6. Gene therapy: proceed with caution.

    PubMed

    Grobstein, C; Flower, M

    1984-04-01

    On 6 February 1984 the Recombinant DNA Advisory Committee of the National Institutes of Health approved a recommendation that the committee provide prior review of research protocols involving human gene therapy. Grobstein and Flower trace the development of public policy in response to concerns about the dangers of gene therapy, especially as it applies to germ line alteration. They offer guidelines and propose principles for an oversight body to confront the immediate and long term technical, social, and ethical implications of human genetic modification. An accompanying article presents a plea for the development of gene therapy by the mother of three children who have sickle cell anemia.

  7. Cell therapy using retinal progenitor cells shows therapeutic effect in a chemically-induced rotenone mouse model of Leber hereditary optic neuropathy

    PubMed Central

    Mansergh, Fiona C; Chadderton, Naomi; Kenna, Paul F; Gobbo, Oliviero L; Farrar, G Jane

    2014-01-01

    Primary mitochondrial disorders occur at a prevalence of one in 10 000; ∼50% of these demonstrate ocular pathology. Leber hereditary optic neuropathy (LHON) is the most common primary mitochondrial disorder. LHON results from retinal ganglion cell pathology, which leads to optic nerve degeneration and blindness. Over 95% of cases result from one of the three common mutations in mitochondrial genes MTND1, MTND4 and MTND6, which encode elements of the complex I respiratory chain. Various therapies for LHON are in development, for example, intravitreal injection of adeno-associated virus carrying either the yeast NDI1 gene or a specific subunit of mammalian Complex I have shown visual improvement in animal models. Given the course of LHON, it is likely that in many cases prompt administration may be necessary before widespread cell death. An alternative approach for therapy may be the use of stem cells to protect visual function; this has been evaluated by us in a rotenone-induced model of LHON. Freshly dissected embryonic retinal cells do not integrate into the ganglion cell layer (GCL), unlike similarly obtained photoreceptor precursors. However, cultured retinal progenitor cells can integrate in close proximity to the GCL, and act to preserve retinal function as assessed by manganese-enhanced magnetic resonance imaging, optokinetic responses and ganglion cell counts. Cell therapies for LHON therefore represent a promising therapeutic approach, and may be of particular utility in treating more advanced disease. PMID:24569607

  8. The promise of gene therapy.

    PubMed

    Pergament, Eugene

    2016-04-01

    The promise of gene therapy performed in the preimplantation and prenatal periods of pregnancy is rapidly becoming a reality. New technologies capable of making designed changes in single nucleotides make germline gene therapy possible. The article reviews the ethical and technical challenges of germline gene therapy. Clustered regularly interspaced short palindromic repeats and related technologies are capable of deleting and inserting specific DNA sequences in mutated genes so as to correct the targeted DNA. The ability to target specific gene mutations will offer unique opportunities to at risk families, particularly those whose genotypes prevent any chance of a normal pregnancy outcome. Other applications of gene-modifying technologies on gametes, zygotes, and embryos are likely in the near future. There will be renewed debates on the potentially controversial applications of these technologies because of their capability to genetically alter the human germline and thereby future generations.

  9. Autosomal Dominant Retinal Degeneration and Bone Loss in Patients with a 12-bp Deletion in the CRX Gene

    PubMed Central

    Tzekov, Radouil T.; Liu, Yuhui; Sohocki, Melanie M.; Zack, Donald J.; Daiger, Stephen P.; Heckenlively, John R.; Birch, David G.

    2008-01-01

    Purpose To define the phenotypic expression of a deletion in the gene encoding the transcription factor CRX in a large, seven-generation, white family. Methods Fourteen affected individuals, all heterozygous for the Leu146del12 mutation in the cone-rod homeobox gene (CRX), and four nonaffected relatives from the same family were examined with visual function tests, and 10 underwent bone mineral density (BMD) measurement. Results The ability of the mutated CRX protein to transactivate rhodopsin promoter was decreased by approximately 25%, and its ability to react synergistically with neural retinal leucine zipper (NRL) was reduced by more than 30%. The affected members of the family had an autosomal dominant ocular condition most closely resembling Leber congenital amaurosis (LCA) with severe visual impairment at an early age. Depending on age, affected members showed varying degrees of significant visual acuity loss, elevated dark-adaptation thresholds, significantly reduced cone and rod electroretinogram (ERG) amplitudes, and progressive constriction of the visual fields, in most cases leading to complete blindness. Six affected members had reduced levels of BMD in the spine and the hip (osteopenia). Four affected female members who were receiving long-term hormonal replacement therapy (HRT) demonstrated normal values of BMD. Conclusions This large deletion of the CRX gene is associated with a severe form of autosomal dominant retinal degeneration. Affected members not receiving HRT showed reduced BMD (osteopenia). This phenotype may reflect the abnormal influence of mutant CRX on both retinal and pineal development. PMID:11328746

  10. Gene Therapy in Heart Failure.

    PubMed

    Fargnoli, Anthony S; Katz, Michael G; Bridges, Charles R; Hajjar, Roger J

    2016-10-28

    Heart failure is a significant burden to the global healthcare system and represents an underserved market for new pharmacologic strategies, especially therapies which can address root cause myocyte dysfunction. Modern drugs, surgeries, and state-of-the-art interventions are costly and do not improve survival outcome measures. Gene therapy is an attractive strategy, whereby selected gene targets and their associated regulatory mechanisms can be permanently managed therapeutically in a single treatment. This in theory could be sustainable for the patient's life. Despite the promise, however, gene therapy has numerous challenges that must be addressed together as a treatment plan comprising these key elements: myocyte physiologic target validation, gene target manipulation strategy, vector selection for the correct level of manipulation, and carefully utilizing an efficient delivery route that can be implemented in the clinic to efficiently transfer the therapy within safety limits. This chapter summarizes the key developments in cardiac gene therapy from the perspective of understanding each of these components of the treatment plan. The latest pharmacologic gene targets, gene therapy vectors, delivery routes, and strategies are reviewed.

  11. Gene therapy on the move

    PubMed Central

    Kaufmann, Kerstin B; Büning, Hildegard; Galy, Anne; Schambach, Axel; Grez, Manuel

    2013-01-01

    The first gene therapy clinical trials were initiated more than two decades ago. In the early days, gene therapy shared the fate of many experimental medicine approaches and was impeded by the occurrence of severe side effects in a few treated patients. The understanding of the molecular and cellular mechanisms leading to treatment- and/or vector-associated setbacks has resulted in the development of highly sophisticated gene transfer tools with improved safety and therapeutic efficacy. Employing these advanced tools, a series of Phase I/II trials were started in the past few years with excellent clinical results and no side effects reported so far. Moreover, highly efficient gene targeting strategies and site-directed gene editing technologies have been developed and applied clinically. With more than 1900 clinical trials to date, gene therapy has moved from a vision to clinical reality. This review focuses on the application of gene therapy for the correction of inherited diseases, the limitations and drawbacks encountered in some of the early clinical trials and the revival of gene therapy as a powerful treatment option for the correction of monogenic disorders. PMID:24106209

  12. Retinitis pigmentosa

    PubMed Central

    Hamel, Christian

    2006-01-01

    Retinitis pigmentosa (RP) is an inherited retinal dystrophy caused by the loss of photoreceptors and characterized by retinal pigment deposits visible on fundus examination. Prevalence of non syndromic RP is approximately 1/4,000. The most common form of RP is a rod-cone dystrophy, in which the first symptom is night blindness, followed by the progressive loss in the peripheral visual field in daylight, and eventually leading to blindness after several decades. Some extreme cases may have a rapid evolution over two decades or a slow progression that never leads to blindness. In some cases, the clinical presentation is a cone-rod dystrophy, in which the decrease in visual acuity predominates over the visual field loss. RP is usually non syndromic but there are also many syndromic forms, the most frequent being Usher syndrome. To date, 45 causative genes/loci have been identified in non syndromic RP (for the autosomal dominant, autosomal recessive, X-linked, and digenic forms). Clinical diagnosis is based on the presence of night blindness and peripheral visual field defects, lesions in the fundus, hypovolted electroretinogram traces, and progressive worsening of these signs. Molecular diagnosis can be made for some genes, but is not usually performed due to the tremendous genetic heterogeneity of the disease. Genetic counseling is always advised. Currently, there is no therapy that stops the evolution of the disease or restores the vision, so the visual prognosis is poor. The therapeutic approach is restricted to slowing down the degenerative process by sunlight protection and vitaminotherapy, treating the complications (cataract and macular edema), and helping patients to cope with the social and psychological impact of blindness. However, new therapeutic strategies are emerging from intensive research (gene therapy, neuroprotection, retinal prosthesis). PMID:17032466

  13. Transcriptome of Atoh7 retinal progenitor cells identifies new Atoh7-dependent regulatory genes for retinal ganglion cell formation.

    PubMed

    Gao, Zhiguang; Mao, Chai-An; Pan, Ping; Mu, Xiuqian; Klein, William H

    2014-11-01

    The bHLH transcription factor ATOH7 (Math5) is essential for establishing retinal ganglion cell (RGC) fate. However, Atoh7-expressing retinal progenitor cells (RPCs) can give rise to all retinal cell types, suggesting that other factors are involved in specifying RGCs. The basis by which a subpopulation of Atoh7-expressing RPCs commits to an RGC fate remains uncertain but is of critical importance to retinal development since RGCs are the earliest cell type to differentiate. To better understand the regulatory mechanisms leading to cell-fate specification, a binary genetic system was generated to specifically label Atoh7-expressing cells with green fluorescent protein (GFP). Fluorescence-activated cell sorting (FACS)-purified GFP(+) and GFP(-) cells were profiled by RNA-seq. Here, we identify 1497 transcripts that were differentially expressed between the two RPC populations. Pathway analysis revealed diminished growth factor signaling in Atoh7-expressing RPCs, indicating that these cells had exited the cell cycle. In contrast, axon guidance signals were enriched, suggesting that axons of Atoh7-expressing RPCs were already making synaptic connections. Notably, many genes enriched in Atoh7-expressing RPCs encoded transcriptional regulators, and several were direct targets of ATOH7, including, and unexpectedly, Ebf3 and Eya2. We present evidence for a Pax6-Atoh7-Eya2 pathway that acts downstream of Atoh7 but upstream of differentiation factor Pou4f2. EYA2 is a protein phosphatase involved in protein-protein interactions and posttranslational regulation. These properties, along with Eya2 as an early target gene of ATOH7, suggest that EYA2 functions in RGC specification. Our results expand current knowledge of the regulatory networks operating in Atoh7-expressing RPCs and offer new directions for exploring the earliest aspects of retinogenesis. © 2014 Wiley Periodicals, Inc.

  14. Gene Therapy for Childhood Neurofibromatosis

    DTIC Science & Technology

    2014-05-01

    AD_________________ Award Number: W81XWH-13-1-0101 TITLE: Gene Therapy for Childhood ...May 2014 4. TITLE AND SUBTITLE Gene Therapy for Childhood Neurofibromatosis 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-13-1-0101 5c...technology. This approach still represents a plausible and very different way to treat childhood neurofibromatosis, as well as other solid tumors

  15. Gene Therapy for Pituitary Tumors

    PubMed Central

    Seilicovich, Adriana; Pisera, Daniel; Sciascia, Sandra A.; Candolfi, Marianela; Puntel, Mariana; Xiong, Weidong; Jaita, Gabriela; Castro, Maria G.

    2009-01-01

    Pituitary tumors are the most common primary intracranial neoplasms. Although most pituitary tumors are considered typically benign, others can cause severe and progressive disease. The principal aims of pituitary tumor treatment are the elimination or reduction of the tumor mass, normalization of hormone secretion and preservation of remaining pituitary function. In spite of major advances in the therapy of pituitary tumors, for some of the most difficult tumors, current therapies that include medical, surgical and radiotherapeutic methods are often unsatisfactory and there is a need to develop new treatment strategies. Gene therapy, which uses nucleic acids as drugs, has emerged as an attractive therapeutic option for the treatment of pituitary tumors that do not respond to classical treatment strategies if the patients become intolerant to the therapy. The development of animal models for pituitary tumors and hormone hypersecretion has proven to be critical for the implementation of novel treatment strategies and gene therapy approaches. Preclinical trials using several gene therapy approaches for the treatment of anterior pituitary diseases have been successfully implemented. Several issues need to be addressed before clinical implementation becomes a reality, including the development of more effective and safer viral vectors, uncovering novel therapeutic targets and development of targeted expression of therapeutic transgenes. With the development of efficient gene delivery vectors allowing long-term transgene expression with minimal toxicity, gene therapy will become one of the most promising approaches for treating pituitary adenomas. PMID:16457646

  16. Gene therapy for age-related macular degeneration.

    PubMed

    Moore, Nicholas A; Bracha, Peter; Hussain, Rehan M; Morral, Nuria; Ciulla, Thomas A

    2017-10-01

    In neovascular age related macular degeneration (nAMD), gene therapy to chronically express anti-vascular endothelial growth factor (VEGF) proteins could ameliorate the treatment burden of chronic intravitreal therapy and improve limited visual outcomes associated with 'real world' undertreatment. Areas covered: In this review, the authors assess the evolution of gene therapy for AMD. Adeno-associated virus (AAV) vectors can transduce retinal pigment epithelium; one such early application was a phase I trial of AAV2-delivered pigment epithelium derived factor gene in advanced nAMD. Subsequently, gene therapy for AMD shifted to the investigation of soluble fms-like tyrosine kinase-1 (sFLT-1), an endogenously expressed VEGF inhibitor, binding and neutralizing VEGF-A. After some disappointing results, research has centered on novel vectors, including optimized AAV2, AAV8 and lentivirus, as well as genes encoding other anti-angiogenic proteins, including ranibizumab, aflibercept, angiostatin and endostatin. Also, gene therapy targeting the complement system is being investigated for geographic atrophy due to non-neovascular AMD. Expert opinion: The success of gene therapy for AMD will depend on the selection of the most appropriate therapeutic protein and its level of chronic expression. Future investigations will center on optimizing vector, promoter and delivery methods, and evaluating the risks of the chronic expression of anti-angiogenic or anti-complement proteins.

  17. Progressive morphological changes and impaired retinal function associated with temporal regulation of gene expression after retinal ischemia/reperfusion injury in mice

    PubMed Central

    2013-01-01

    Retinal ischemia/reperfusion (I/R) injury is an important cause of visual impairment. However, questions remain on the overall I/R mechanisms responsible for progressive damage to the retina. In this study, we used a mouse model of I/R and characterized the pathogenesis by analyzing temporal changes of retinal morphology and function associated with changes in retinal gene expression. Transient ischemia was induced in one eye of C57BL/6 mice by raising intraocular pressure to 120 mmHg for 60 min followed by retinal reperfusion by restoring normal pressure. At various time points post I/R, retinal changes were monitored by histological assessment with H&E staining and by SD-OCT scanning. Retinal function was also measured by scotopic ERG. Temporal changes in retinal gene expression were analyzed using cDNA microarrays and real-time RT-PCR. In addition, retinal ganglion cells and gliosis were observed by immunohistochemistry. H&E staining and SD-OCT scanning showed an initial increase followed by a significant reduction of retinal thickness in I/R eyes accompanied with cell loss compared to contralateral control eyes. The greatest reduction in thickness was in the inner plexiform layer (IPL) and inner nuclear layer (INL). Retinal detachment was observed at days 3 and 7 post- I/R injury. Scotopic ERG a- and b-wave amplitudes and implicit times were significantly impaired in I/R eyes compared to contralateral control eyes. Microarray data showed temporal changes in gene expression involving various gene clusters such as molecular chaperones and inflammation. Furthermore, immunohistochemical staining confirmed Müller cell gliosis in the damaged retinas. The time-dependent changes in retinal morphology were significantly associated with functional impairment and altered retinal gene expression. We demonstrated that I/R-mediated morphological changes the retina closely associated with functional impairment as well as temporal changes in retinal gene expression. Our

  18. Vectors for cancer gene therapy.

    PubMed

    Zhang, J; Russell, S J

    1996-09-01

    Many viral and non-viral vector systems have now been developed for gene therapy applications. In this article, the pros and cons of these vector systems are discussed in relation to the different cancer gene therapy strategies. The protocols used in cancer gene therapy can be broadly divided into six categories including gene transfer to explanted cells for use as cell-based cancer vaccines; gene transfer to a small number of tumour cells in situ to achieve a vaccine effect; gene transfer to vascular endothelial cells (VECs) lining the blood vessels of the tumour to interfere with tumour angiogenesis; gene transfer to T lymphocytes to enhance their antitumour effector capability; gene transfer to haemopoietic stem cells (HSCs) to enhance their resistance to cytotoxic drugs and gene transfer to a large number of tumour cells in situ to achieve nonimmune tumour reduction with or without bystander effect. Each of the six strategies makes unique demands on the vector system and these are discussed with reference to currently available vectors. Aspects of vector biology that are in need of further development are discussed in some detail. The final section points to the potential use of replicating viruses as delivery vehicles for efficient in vivo gene transfer to disseminated cancers.

  19. The ADAMTS18 gene is responsible for autosomal recessive early onset severe retinal dystrophy.

    PubMed

    Peluso, Ivana; Conte, Ivan; Testa, Francesco; Dharmalingam, Gopuraja; Pizzo, Mariateresa; Collin, Rob W J; Meola, Nicola; Barbato, Sara; Mutarelli, Margherita; Ziviello, Carmela; Barbarulo, Anna Maria; Nigro, Vincenzo; Melone, Mariarosa A B; Simonelli, Francesca; Banfi, Sandro

    2013-01-28

    Inherited retinal dystrophies, including Retinitis Pigmentosa and Leber Congenital Amaurosis among others, are a group of genetically heterogeneous disorders that lead to variable degrees of visual deficits. They can be caused by mutations in over 100 genes and there is evidence for the presence of as yet unidentified genes in a significant proportion of patients. We aimed at identifying a novel gene for an autosomal recessive form of early onset severe retinal dystrophy in a patient carrying no previously described mutations in known genes. An integrated strategy including homozygosity mapping and whole exome sequencing was used to identify the responsible mutation. Functional tests were performed in the medaka fish (Oryzias latipes) model organism to gain further insight into the pathogenic role of the ADAMTS18 gene in eye and central nervous system (CNS) dysfunction. This study identified, in the analyzed patient, a homozygous missense mutation in the ADAMTS18 gene, which was recently linked to Knobloch syndrome, a rare developmental disorder that affects the eye and the occipital skull. In vivo gene knockdown performed in medaka fish confirmed both that the mutation has a pathogenic role and that the inactivation of this gene has a deleterious effect on photoreceptor cell function. This study reveals that mutations in the ADAMTS18 gene can cause a broad phenotypic spectrum of eye disorders and contribute to shed further light on the complexity of retinal diseases.

  20. Gene Therapy for Metabolic Diseases

    PubMed Central

    Chandler, Randy J.; Venditti, Charles P.

    2016-01-01

    SUMMARY Gene therapy has recently shown great promise as an effective treatment for a number of metabolic diseases caused by genetic defects in both animal models and human clinical trials. Most of the current success has been achieved using a viral mediated gene addition approach, but gene-editing technology has progressed rapidly and gene modification is being actively pursued in clinical trials. This review focuses on viral mediated gene addition approaches, because most of the current clinical trials utilize this approach to treat metabolic diseases. PMID:27853673

  1. Gene Therapy in Heart Failure

    PubMed Central

    Vinge, Leif Erik; Raake, Philip W.; Koch, Walter J.

    2008-01-01

    With increasing knowledge of basic molecular mechanisms governing the development of heart failure (HF), the possibility of specifically targeting key pathological players is evolving. Technology allowing for efficient in vivo transduction of myocardial tissue with long-term expression of a transgene enables translation of basic mechanistic knowledge into potential gene therapy approaches. Gene therapy in HF is in its infancy clinically with the predominant amount of experience being from animal models. Nevertheless, this challenging and promising field is gaining momentum as recent preclinical studies in larger animals have been carried out and, importantly, there are 2 newly initiated phase I clinical trials for HF gene therapy. To put it simply, 2 parameters are needed for achieving success with HF gene therapy: (1) clearly identified detrimental/beneficial molecular targets; and (2) the means to manipulate these targets at a molecular level in a sufficient number of cardiac cells. However, several obstacles do exist on our way to efficient and safe gene transfer to human myocardium. Some of these obstacles are discussed in this review; however, it primarily focuses on the molecular target systems that have been subjected to intense investigation over the last decade in an attempt to make gene therapy for human HF a reality. PMID:18566312

  2. Perspectives on Best Practices for Gene Therapy Programs

    PubMed Central

    Cheever, Thomas R.; Berkley, Dale; Braun, Serge; Brown, Robert H.; Byrne, Barry J.; Chamberlain, Jeffrey S.; Cwik, Valerie; Duan, Dongsheng; Federoff, Howard J.; High, Katherine A.; Kaspar, Brian K.; Klinger, Katherine W.; Larkindale, Jane; Lincecum, John; Mavilio, Fulvio; McDonald, Cheryl L.; McLaughlin, James; Weiss McLeod, Bonnie; Mendell, Jerry R.; Nuckolls, Glen; Stedman, Hansell H.; Tagle, Danilo A.; Vandenberghe, Luk H.; Wang, Hao; Wernett, Pamela J.; Wilson, James M.; Porter, John D.

    2015-01-01

    Abstract With recent successes in gene therapy trials for hemophilia and retinal diseases, the promise and prospects for gene therapy are once again garnering significant attention. To build on this momentum, the National Institute of Neurological Disorders and Stroke and the Muscular Dystrophy Association jointly hosted a workshop in April 2014 on “Best Practices for Gene Therapy Programs,” with a focus on neuromuscular disorders. Workshop participants included researchers from academia and industry as well as representatives from the regulatory, legal, and patient advocacy sectors to cover the gamut from preclinical optimization to intellectual property concerns and regulatory approval. The workshop focused on three key issues in the field: (1) establishing adequate scientific premise for clinical trials in gene therapy, (2) addressing regulatory process issues, and (3) intellectual property and commercialization issues as they relate to gene therapy. The outcomes from the discussions at this workshop are intended to provide guidance for researchers and funders in the gene therapy field. PMID:25654329

  3. Gene therapy and peripheral nerve repair: a perspective.

    PubMed

    Hoyng, Stefan A; de Winter, Fred; Tannemaat, Martijn R; Blits, Bas; Malessy, Martijn J A; Verhaagen, Joost

    2015-01-01

    Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan's, Parkinson's (PD) and Alzheimer's disease (AD), retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV) and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translational research on gene therapy to promote peripheral nervous system (PNS) repair. This short review first summarizes the results of gene therapy in animal models for peripheral nerve repair. Secondly, we identify key areas of future research in the domain of PNS-gene therapy. Finally, a perspective is provided on the path to clinical translation of PNS-gene therapy for traumatic nerve injuries. In the latter section we discuss the route and mode of delivery of the vector to human patients, the efficacy and safety of the vector, and the choice of the patient population for a first possible proof-of-concept clinical study.

  4. Gene therapy and peripheral nerve repair: a perspective

    PubMed Central

    Hoyng, Stefan A.; de Winter, Fred; Tannemaat, Martijn R.; Blits, Bas; Malessy, Martijn J. A.; Verhaagen, Joost

    2015-01-01

    Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan’s, Parkinson’s (PD) and Alzheimer’s disease (AD), retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV) and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translational research on gene therapy to promote peripheral nervous system (PNS) repair. This short review first summarizes the results of gene therapy in animal models for peripheral nerve repair. Secondly, we identify key areas of future research in the domain of PNS-gene therapy. Finally, a perspective is provided on the path to clinical translation of PNS-gene therapy for traumatic nerve injuries. In the latter section we discuss the route and mode of delivery of the vector to human patients, the efficacy and safety of the vector, and the choice of the patient population for a first possible proof-of-concept clinical study. PMID:26236188

  5. Gene therapy in the cornea.

    PubMed

    Mohan, Rajiv R; Sharma, Ajay; Netto, Marcelo V; Sinha, Sunilima; Wilson, Steven E

    2005-09-01

    Technological advances in the field of gene therapy has prompted more than three hundred phase I and phase II gene-based clinical trials for the treatment of cancer, AIDS, macular degeneration, cardiovascular, and other monogenic diseases. Besides treating diseases, gene transfer technology has been utilized for the development of preventive and therapeutic vaccines for malaria, tuberculosis, hepatitis A, B and C viruses, AIDS, and influenza. The potential therapeutic applications of gene transfer technology are enormous. The cornea is an excellent candidate for gene therapy because of its accessibility and immune-privileged nature. In the last two decades, various viral vectors, such as adeno, adeno-associated, retro, lenti, and herpes simplex, as well as non-viral methods, were examined for introducing DNA into corneal cells in vitro, in vivo and ex vivo. Most of these studies used fluorescent or non-fluorescent marker genes to track the level and duration of transgene expression in corneal cells. However, limited studies were directed to evaluate prospects of gene-based interventions for corneal diseases or disorders such as allograft rejection, laser-induced post-operative haze, herpes simplex keratitis, and wound healing in animal models. We will review the successes and obstacles impeding gene therapy approaches used for delivering genes into the cornea.

  6. In vivo versus ex vivo CRISPR therapies for retinal dystrophy

    PubMed Central

    Bakondi, Benjamin

    2017-01-01

    SUMMARY Two therapeutic paths have been proposed to treat inherited retinal dystrophy using clustered regularly interspaced short palindromic repeats (CRISPR). One strategy is to genetically correct patient cells ex vivo for autologous transplant, whereas the second is to modify cells in vivo by delivering CRISPR effectors to the retina. The feasibility of both editing strategies has been demonstrated within three years of CRISPR’s adaptation to mammalian systems. However, the functional integration of transplanted cells into host retinae has been a long-standing challenge that currently represents the 2025 moonshot of the National Eye Institute’s Audacious Goals Initiative. The clinical translatability of each path is discussed with regard to current investigations and whether cell replacement can be circumvented by in vivo editing. PMID:28163772

  7. Apoptotic genes in cancer therapy.

    PubMed

    Opalka, Bertram; Dickopp, Alexandra; Kirch, Hans-Christoph

    2002-01-01

    Induction of apoptosis in malignant cells is a major goal of cancer therapy in general and of certain cancer gene therapy strategies in particular. Numerous apoptosis-regulating genes have been evaluated for this purpose. Besides the most prominent p53 gene others include p16, p21, p27, E2F genes, FHIT, PTEN and CASPASE genes. Recently, the potential for therapy of an adenoviral gene, E1A, known for a long time for its apoptosis-inducing activity, has been discovered. In experimental settings, these genes have proven their tumor-suppressive and apoptosis-inducing activity. Clinical trials are currently being performed with selected genes. By far the most studies transfer the p53 gene using retro- or adenoviral vectors. Disease stabilization or other benefits were observed in a limited number of patients when p53 was applied alone or in combination with cytotoxic drugs. A second proapoptotic gene that has entered clinical trials is adenovirus E1A. Here, too, disease stabilization as well as/or local regression in one case have been demonstrated in selected patients. In all cases, side effects were tolerable. To further improve E1A as a therapeutic transgene, we have deleted transforming domains from the adenovirus 5 and 12 13S cDNAs. Mutants were derived which had completely lost their transforming activity in combination with the E1B oncogene but retained a pronounced tumor-suppressive activity. Cells transduced with these constructs showed a highly reduced ability to grow in soft agar, and tumor growth in nude mice could be substantially suppressed. Outgrowing tumors had lost E1A expression when analyzed in Western blots. These E1A constructs may represent valuable tools for cancer gene therapy in the future.

  8. Lung gene therapy-How to capture illumination from the light already present in the tunnel.

    PubMed

    Xia, Emily; Munegowda, Manjunatha Ankathatti; Cao, Huibi; Hu, Jim

    2014-09-01

    Gene therapy has been considered as the most ideal medical intervention for genetic diseases because it is intended to target the cause of diseases instead of disease symptoms. Availability of techniques for identification of genetic mutations and for in vitro manipulation of genes makes it practical and attractive. After the initial hype in 1990s and later disappointments in clinical trials for more than a decade, light has finally come into the tunnel in recent years, especially in the field of eye gene therapy where it has taken big strides. Clinical trials in gene therapy for retinal degenerative diseases such as Leber's congenital amaurosis (LCA) and choroideremia demonstrated clear therapeutic efficacies without apparent side effects. Although these successful examples are still rare and sporadic in the field, they provide the proof of concept for harnessing the power of gene therapy to treat genetic diseases and to modernize our medication. In addition, those success stories illuminate the path for the development of gene therapy treating other genetic diseases. Because of the differences in target organs and cells, distinct barriers to gene delivery exist in gene therapy for each genetic disease. It is not feasible for authors to review the current development in the entire field. Thus, in this article, we will focus on what we can learn from the current success in gene therapy for retinal degenerative diseases to speed up the gene therapy development for lung diseases, such as cystic fibrosis.

  9. Gene therapy for bone regeneration.

    PubMed

    Luo, Jeffrey; Sun, Michael H; Kang, Quan; Peng, Ying; Jiang, Wei; Luu, Hue H; Luo, Qing; Park, Jae Yoon; Li, Yien; Haydon, Rex C; He, Tong-Chuan

    2005-04-01

    Efficacious bone regeneration could revolutionize the clinical management of many bone and musculoskeletal disorders. Bone has the unique ability to regenerate and continuously remodel itself throughout life. However, clinical situations arise when bone is unable to heal itself, as with segmental bone loss, fracture non-union, and failed spinal fusion. This leads to significant morbidity and mortality. Current attempts at improved bone healing have been met with limited success, fueling the development of improved techniques. Gene therapy in many ways represents an ideal approach for augmenting bone regeneration. Gene therapy allows specific gene products to be delivered to a precise anatomic location. In addition, the level of transgene expression as well as the duration of expression can be regulated with current techniques. For bone regeneration, the gene of interest should be delivered to the fracture site, expressed at appropriate levels, and then deactivated once the fracture has healed. Delivery of biological factors, mostly bone morphogenetic proteins (BMPs), has yielded promising results both in animal and clinical studies. There has also been tremendous work on discovering new growth factors and exploring previously defined ones. Finally, significant advances are being made in the delivery systems of the genes, ranging from viral and non-viral vectors to tissue engineering scaffolds. Despite some public hesitation to gene therapy, its use has great potential to expand our ability to treat a variety of human bone and musculoskeletal disorders. It is conceivable that in the near future gene therapy can be utilized to induce bone formation in virtually any region of the body in a minimally invasive manner. As bone biology and gene therapy research progresses, the goal of successful human gene transfer for augmentation of bone regeneration draws nearer.

  10. Delivery systems for gene therapy.

    PubMed

    Mali, Shrikant

    2013-01-01

    The structure of DNA was unraveled by Watson and Crick in 1953, and two decades later Arber, Nathans and Smith discovered DNA restriction enzymes, which led to the rapid growth in the field of recombinant DNA technology. From expressing cloned genes in bacteria to expressing foreign DNA in transgenic animals, DNA is now slated to be used as a therapeutic agent to replace defective genes in patients suffering from genetic disorders or to kill tumor cells in cancer patients. Gene therapy provides modern medicine with new perspectives that were unthinkable two decades ago. Progress in molecular biology and especially, molecular medicine is now changing the basics of clinical medicine. A variety of viral and non-viral possibilities are available for basic and clinical research. This review summarizes the delivery routes and methods for gene transfer used in gene therapy.

  11. Prediction of Cis-Regulatory Elements Controlling Genes Differentially Expressed by Retinal and Choroidal Vascular Endothelial Cells.

    PubMed

    Choi, Dongseok; Appukuttan, Binoy; Binek, Sierra J; Planck, Stephen R; Stout, J Timothy; Rosenbaum, James T; Smith, Justine R

    2008-01-01

    Cultured endothelial cells of the human retina and choroid demonstrate distinct patterns of gene expression. We hypothesized that differential gene expression reflected differences in the interactions of transcription factors and respective cis-regulatory motifs(s) in these two emdothelial cell subpopulations, recognizing that motifs often exist as modules. We tested this hypothesis in silico by using TRANSFAC Professional and CisModule to identify cis-regulatory motifs and modules in genes that were differentially expressed by human retinal versus choroidal endothelial cells, as identified by analysis of a microarray data set. Motifs corresponding to eight transcription factors were significantly (p < 0.05) differentially abundant in genes that were relatively highly expressed in retinal (i.e., GCCR, HMGIY, HSF1, p53, VDR) or choroidal (i.e., E2F, YY1, ZF5) endothelial cells. Predicted cis-regulatory modules were quite different for these two groups of genes. Our findings raise the possibility of exploiting specific cis-regulatory motifs to target therapy at the ocular endothelial cells subtypes responsible for neovascular age-related macular degeneration or proliferative diabetic retinopathy.

  12. Gene delivery into mouse retinal ganglion cells by in utero electroporation

    PubMed Central

    Garcia-Frigola, Cristina; Carreres, Maria Isabel; Vegar, Celia; Herrera, Eloisa

    2007-01-01

    Background The neural retina is a highly structured tissue of the central nervous system that is formed by seven different cell types that are arranged in layers. Despite much effort, the genetic mechanisms that underlie retinal development are still poorly understood. In recent years, large-scale genomic analyses have identified candidate genes that may play a role in retinal neurogenesis, axon guidance and other key processes during the development of the visual system. Thus, new and rapid techniques are now required to carry out high-throughput analyses of all these candidate genes in mammals. Gene delivery techniques have been described to express exogenous proteins in the retina of newborn mice but these approaches do not efficiently introduce genes into the only retinal cell type that transmits visual information to the brain, the retinal ganglion cells (RGCs). Results Here we show that RGCs can be targeted for gene expression by in utero electroporation of the eye of mouse embryos. Accordingly, using this technique we have monitored the morphology of electroporated RGCs expressing reporter genes at different developmental stages, as well as their projection to higher visual targets. Conclusion Our method to deliver ectopic genes into mouse embryonic retinas enables us to follow the course of the entire retinofugal pathway by visualizing RGC bodies and axons. Thus, this technique will permit to perform functional studies in vivo focusing on neurogenesis, axon guidance, axon projection patterning or neural connectivity in mammals. PMID:17875204

  13. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) cause the RP10 form of autosomal dominant retinitis pigmentosa

    PubMed Central

    Bowne, Sara J.; Sullivan, Lori S.; Blanton, Susan H.; Cepko, Constance L.; Blackshaw, Seth; Birch, David G.; Hughbanks-Wheaton, Dianna; Heckenlively, John R.; Daiger, Stephen P.

    2008-01-01

    Autosomal dominant retinitis pigmentosa (adRP) is a heterogeneous set of progressive retinopathies caused by several distinct genes. One locus, the RP10 form of adRP, maps to human chromosome 7q31.1 and may account for 5–10% of adRP cases among Americans and Europeans. We identified two American families with the RP10 form of adRP by linkage mapping and used these families to reduce the linkage interval to 3.45 Mb between the flanking markers D7S686 and RP-STR8. Sequence and transcript analysis identified 54 independent genes within this region, at least 10 of which are retinal-expressed and thus candidates for the RP10 gene. A screen of retinal transcripts comparing retinas from normal mice to retinas from crx−/crx− knockout mice (with poorly differentiated photoreceptors) demonstrated a 6-fold reduction in one candidate, inosine monophosphate dehydrogenase 1 (IMPDH1; EC 1.1.1.205). Since many of the genes known to cause retinitis pigmentosa are under CRX control in photoreceptors, IMPDH1 became a high-priority candidate for mutation screening. DNA sequencing of affected individuals from the two American RP10 families revealed a GAC→AAC transition in codon 226 substituting an asparagine for an aspartic acid in both families. The identical mutation was also found in a British RP10 family. The Asp226Asn missense mutation is present in all affected individuals tested and absent from unaffected controls. The aspartic acid at codon 226 is conserved in all IMPDH genes, in all species examined, including bacteria, suggesting that this mutation is highly deleterious. Subsequent screening of probands from 60 other adRP families revealed an additional family with this mutation, confirming its association with retinitis pigmentosa and the relatively high frequency of this mutation. Another IMPDH1 substitution, Val268Ile, was also observed in this cohort of patients but not in controls. IMPDH1 is a ubiquitously expressed enzyme, functioning as a homotetramer, which

  14. Mutations in the inosine monophosphate dehydrogenase 1 gene (IMPDH1) cause the RP10 form of autosomal dominant retinitis pigmentosa.

    PubMed

    Bowne, Sara J; Sullivan, Lori S; Blanton, Susan H; Cepko, Constance L; Blackshaw, Seth; Birch, David G; Hughbanks-Wheaton, Dianna; Heckenlively, John R; Daiger, Stephen P

    2002-03-01

    Autosomal dominant retinitis pigmentosa (adRP) is a heterogeneous set of progressive retinopathies caused by several distinct genes. One locus, the RP10 form of adRP, maps to human chromosome 7q31.1 and may account for 5-10% of adRP cases among Americans and Europeans. We identified two American families with the RP10 form of adRP by linkage mapping and used these families to reduce the linkage interval to 3.45 Mb between the flanking markers D7S686 and RP-STR8. Sequence and transcript analysis identified 54 independent genes within this region, at least 10 of which are retinal-expressed and thus candidates for the RP10 gene. A screen of retinal transcripts comparing retinas from normal mice to retinas from crx-/crx- knockout mice (with poorly differentiated photoreceptors) demonstrated a 6-fold reduction in one candidate, inosine monophosphate dehydrogenase 1 (IMPDH1; EC 1.1.1.205). Since many of the genes known to cause retinitis pigmentosa are under CRX control in photoreceptors, IMPDH1 became a high-priority candidate for mutation screening. DNA sequencing of affected individuals from the two American RP10 families revealed a GAC-->AAC transition in codon 226 substituting an asparagine for an aspartic acid in both families. The identical mutation was also found in a British RP10 family. The Asp226Asn missense mutation is present in all affected individuals tested and absent from unaffected controls. The aspartic acid at codon 226 is conserved in all IMPDH genes, in all species examined, including bacteria, suggesting that this mutation is highly deleterious. Subsequent screening of probands from 60 other adRP families revealed an additional family with this mutation, confirming its association with retinitis pigmentosa and the relatively high frequency of this mutation. Another IMPDH1 substitution, Val268Ile, was also observed in this cohort of patients but not in controls. IMPDH1 is a ubiquitously expressed enzyme, functioning as a homotetramer, which

  15. Human germline gene therapy reconsidered.

    PubMed

    Resnik, D B; Langer, P J

    2001-07-20

    This paper reevaluates the notion of human germline gene therapy (HGLGT) in light of developments in biomedicine, biotechnology, and ethical and policy analysis. The essay makes the following key points. First, because the distinction among "therapy," "prevention," and "enhancement" is not clear in human genetics, "gene therapy" is an inadequate descriptor of the process and goals of germline genetic alterations. The alternate use of the phrase "human germline genome modification" (HGLGM) could avoid a misleading label. Second, procedures that could be construed as genetic "enhancement" may not be as morally problematic as some have supposed, once one understands that the boundaries between therapy, prevention, and enhancement are not obvious in genetic medicine. Third, HGLGM might be the medically and morally most appropriate way of avoiding the birth of a child with a genetic disease in only a small range of cases. Fourth, there are still many ethical and scientific problems relating to the safety and efficacy of HGLGM.

  16. [Gene therapy and hospital strategy].

    PubMed

    Leclercq, B

    1993-10-01

    Gene therapy raises strong interrogations among hospital managers. Actually, hospital environment is disturbed and moving as well in a legislative political and statutory level as in an economical (competition, consumerism, proximity of the establishments) and demographic one (ageing, new pathologies). The fast development of medical technologies amplifies this disturbance. In front of that environment, the hospital has to anticipate the arriving of gene therapy without underestimating the deontological, medical, economical and judicial risks. The decisions of implantation have to be taken in a collective way, and seriously planned and estimated on a medical and economical level. The way to train people and to forecast their careers don't have to be underestimated in consideration of the challenge which is represented by the gene therapy.

  17. Gene Therapy in Corneal Transplantation

    PubMed Central

    Qazi, Yureeda; Hamrah, Pedram

    2014-01-01

    Corneal transplantation is the most commonly performed organ transplantation. Immune privilege of the cornea is widely recognized, partly because of the relatively favorable outcome of corneal grafts. The first-time recipient of corneal allografts in an avascular, low-risk setting can expect a 90% success rate without systemic immunosuppressive agents and histocompatibility matching. However, immunologic rejection remains the major cause of graft failure, particularly in patients with a high risk for rejection. Corticosteroids remain the first-line therapy for the prevention and treatment of immune rejection. However, current pharmacological measures are limited in their side-effect profiles, repeated application, lack of targeted response, and short duration of action. Experimental ocular gene therapy may thus present new horizons in immunomodulation. From efficient viral vectors to sustainable alternative splicing, we discuss the progress of gene therapy in promoting graft survival and postulate further avenues for gene-mediated prevention of allogeneic graft rejection. PMID:24138037

  18. Vision from next generation sequencing: multi-dimensional genome-wide analysis for producing gene regulatory networks underlying retinal development, aging and disease.

    PubMed

    Yang, Hyun-Jin; Ratnapriya, Rinki; Cogliati, Tiziana; Kim, Jung-Woong; Swaroop, Anand

    2015-05-01

    Genomics and genetics have invaded all aspects of biology and medicine, opening uncharted territory for scientific exploration. The definition of "gene" itself has become ambiguous, and the central dogma is continuously being revised and expanded. Computational biology and computational medicine are no longer intellectual domains of the chosen few. Next generation sequencing (NGS) technology, together with novel methods of pattern recognition and network analyses, has revolutionized the way we think about fundamental biological mechanisms and cellular pathways. In this review, we discuss NGS-based genome-wide approaches that can provide deeper insights into retinal development, aging and disease pathogenesis. We first focus on gene regulatory networks (GRNs) that govern the differentiation of retinal photoreceptors and modulate adaptive response during aging. Then, we discuss NGS technology in the context of retinal disease and develop a vision for therapies based on network biology. We should emphasize that basic strategies for network construction and analyses can be transported to any tissue or cell type. We believe that specific and uniform guidelines are required for generation of genome, transcriptome and epigenome data to facilitate comparative analysis and integration of multi-dimensional data sets, and for constructing networks underlying complex biological processes. As cellular homeostasis and organismal survival are dependent on gene-gene and gene-environment interactions, we believe that network-based biology will provide the foundation for deciphering disease mechanisms and discovering novel drug targets for retinal neurodegenerative diseases. Published by Elsevier Ltd.

  19. Hereditary Retinal Dystrophy.

    PubMed

    Hohman, Thomas C

    2016-12-30

    As our understanding of the genetic basis for inherited retinal disease has expanded, gene therapy has advanced into clinical development. When the gene mutations associated with inherited retinal dystrophies were identified, it became possible to create animal models in which individual gene were altered to match the human mutations. The retina of these animals were then characterized to assess whether the mutated genes produced retinal phenotypes characteristic of disease-affected patients. Following the identification of a subpopulation of patients with the affected gene and the development of techniques for the viral gene transduction of retinal cells, it has become possible to deliver a copy of the normal gene into the retinal sites of the mutated genes. When this was performed in animal models of monogenic diseases, at an early stage of retinal degeneration when the affected cells remained viable, successful gene augmentation corrected the structural and functional lesions characteristic of the specific diseases in the areas of the retina that were successfully transduced. These studies provided the essential proof-of-concept needed to advance monogenic gene therapies into clinic development; these therapies include treatments for: Leber's congenital amaurosis type 2, caused by mutations to RPE65, retinoid isomerohydrolase; choroideremia, caused by mutations to REP1, Rab escort protein 1; autosomal recessive Stargardt disease, caused by mutations to ABCA4, the photoreceptor-specific ATP-binding transporter; Usher 1B disease caused by mutations to MYO7A, myosin heavy chain 7; X-linked juvenile retinoschisis caused by mutations to RS1, retinoschisin; autosomal recessive retinitis pigmentosa caused by mutations to MERTK, the proto-oncogene tyrosine-protein kinase MER; Leber's hereditary optic neuropathy caused by mutations to ND4, mitochondrial nicotinamide adenine dinucleotide ubiquinone oxidoreductase (complex I) subunit 4 and achromatopsia, caused by

  20. Timing of Antioxidant Gene Therapy: Implications for Treating Dry AMD

    PubMed Central

    Biswal, Manas R.; Han, Pingyang; Zhu, Ping; Wang, Zhaoyang; Li, Hong; Ildefonso, Cristhian J.; Lewin, Alfred S.

    2017-01-01

    Purpose To investigate whether antioxidant gene therapy protects the structure and function of retina in a murine model of RPE atrophy, and to determine whether antioxidant gene therapy can prevent degeneration once it has begun. Methods We induced mitochondrial oxidative stress in RPE by conditional deletion of Sod2, the gene for manganese superoxide dismutase (MnSOD). These mice exhibited localized atrophy of the RPE and overlying photoreceptors. We restored Sod2 to the RPE of one eye using adeno-associated virus (AAV) by subretinal injection at an early (6 weeks) and a late stage (6 months), injecting the other eye with an AAV vector expressing green fluorescent protein (GFP). Retinal degeneration was monitored over a period of 9 months by electroretinography (ERG) and spectral-domain optical coherence tomography (SD-OCT). Immunohistochemical and histologic analyses were conducted to measure oxidative stress markers and to visualize retinal structure. Results One month after delivery, the AAV-Sod2 injection resulted in production of MnSod in the RPE and negligible expression in the neural retina. Electroretinography and OCT suggested no adverse effects due to increased expression of MnSOD or subretinal injection. Decrease in the ERG response and thinning retinal thickness was significantly delayed in eyes with early treatment with the Sod2 vector, but treatment at 6 months of age did not affect the ERG decline seen in these mice. Conclusions We conclude that antioxidant gene therapy may be effective in preventing the detrimental effects of oxidative stress, but may not be beneficial once substantial tissue damage has occurred. PMID:28241311

  1. Gene therapy for Down syndrome.

    PubMed

    Fillat, Cristina; Altafaj, Xavier

    2012-01-01

    The presence of an additional copy of HSA21 chromosome in Down syndrome (DS) individuals leads to the overexpression of 30-50% of HSA21 genes. This upregulation can, in turn, trigger a deregulation on the expression of non-HSA21 genes. Moreover, the overdose of HSA21 microRNAs (miRNAs) may result in the downregulation of its target genes. Additional complexity can also arise from epigenetic changes modulating gene expression. Thus, a myriad of transcriptional and posttranscriptional alterations participate to produce abnormal phenotypes in almost all tissues and organs of DS individuals. The study of the physiological roles of genes dysregulated in DS, as well as their characterization in murine models with gene(s) dosage imbalance, pointed out several genes, and functional noncoding elements to be particularly critical in the etiology of DS. Recent findings indicate that gene therapy strategies-based on the introduction of genetic elements by means of delivery vectors-toward the correction of phenotypic abnormalities in DS are also very promising tool to identify HSA21 and non-HSA21 gene candidates, contributing to DS phenotype. In this chapter, we focus on the impact of normalizing the expression levels of up or downregulated genes to rescue particular phenotypes of DS. Attempts toward gene-based treatment approaches in mouse models will be discussed as new opportunities to ameliorate DS alterations.

  2. Association between missense mutations in the BBS2 gene and nonsyndromic retinitis pigmentosa.

    PubMed

    Shevach, Elia; Ali, Manir; Mizrahi-Meissonnier, Liliana; McKibbin, Martin; El-Asrag, Mohammed; Watson, Christopher M; Inglehearn, Chris F; Ben-Yosef, Tamar; Blumenfeld, Anat; Jalas, Chaim; Banin, Eyal; Sharon, Dror

    2015-03-01

    A large number of genes can cause inherited retinal degenerations when mutated. It is important to identify the cause of disease for a better disease prognosis and a possible gene-specific therapeutic intervention. To identify the cause of disease in families with nonsyndromic retinitis pigmentosa. Patients and family members were recruited for the study and underwent clinical evaluation and genetic analyses. Identification of sequence variants in genes using next-generation sequencing. We performed exome sequencing for 4 families, which was followed by Sanger sequencing of the identified mutations in 120 ethnicity-matched patients. In total, we identified 4 BBS2 missense mutations that cause nonsyndromic retinitis pigmentosa. Three siblings of Moroccan Jewish ancestry were compound heterozygotes for p.A33D and p.P134R, and 6 patients belonging to 4 families of Ashkenazi Jewish ancestry were homozygous for either p.D104A or p.R632P, or compound heterozygous for these 2 mutations. The mutations cosegregated with retinitis pigmentosa in the studied families, and the affected amino acid residues are evolutionarily conserved. Our study shows that BBS2 mutations can cause nonsyndromic retinitis pigmentosa and highlights yet another candidate for this genetically heterogeneous condition.

  3. Significant changes in endogenous retinal gene expression assessed 1 year after a single intraocular injection of AAV-CNTF or AAV-BDNF

    PubMed Central

    LeVaillant, Chrisna J; Sharma, Anil; Muhling, Jill; Wheeler, Lachlan PG; Cozens, Greg S; Hellström, Mats; Rodger, Jennifer; Harvey, Alan R

    2016-01-01

    Use of viral vectors to deliver therapeutic genes to the central nervous system holds promise for the treatment of neurodegenerative diseases and neurotrauma. Adeno-associated viral (AAV) vectors encoding brain-derived neurotrophic factor (BDNF) or ciliary derived neurotrophic factor (CNTF) promote the viability and regeneration of injured adult rat retinal ganglion cells. However, these growth-inducing transgenes are driven by a constitutively active promoter, thus we examined whether long-term AAV-mediated secretion of BDNF or CNTF affected endogenous retinal gene expression. One year after the intravitreal injection of AAV-green fluorescent protein (GFP), bi-cistronic AAV-BDNF-GFP or AAV-CNTF-GFP, mRNA was extracted and analyzed using custom 96 well polymerase chain reaction arrays. Of 93 test genes, 56% showed significantly altered expression in AAV-BDNF-GFP and/or AAV-CNTF-GFP retinas compared with AAV-GFP controls. Of these genes, 73% showed differential expression in AAV-BDNF versus AAV-CNTF injected eyes. To focus on retinal ganglion cell changes, quantitative polymerase chain reaction was undertaken on mRNA (16 genes) obtained from fixed retinal sections in which the ganglion cell layer was enriched. The sign and extent of fold changes in ganglion cell layer gene expression differed markedly from whole retinal samples. Sustained and global alteration in endogenous mRNA expression after gene therapy should be factored into any interpretation of experimental/clinical outcomes, particularly when introducing factors into the central nervous system that require secretion to evoke functionality. PMID:27933306

  4. Significant changes in endogenous retinal gene expression assessed 1 year after a single intraocular injection of AAV-CNTF or AAV-BDNF.

    PubMed

    LeVaillant, Chrisna J; Sharma, Anil; Muhling, Jill; Wheeler, Lachlan Pg; Cozens, Greg S; Hellström, Mats; Rodger, Jennifer; Harvey, Alan R

    2016-01-01

    Use of viral vectors to deliver therapeutic genes to the central nervous system holds promise for the treatment of neurodegenerative diseases and neurotrauma. Adeno-associated viral (AAV) vectors encoding brain-derived neurotrophic factor (BDNF) or ciliary derived neurotrophic factor (CNTF) promote the viability and regeneration of injured adult rat retinal ganglion cells. However, these growth-inducing transgenes are driven by a constitutively active promoter, thus we examined whether long-term AAV-mediated secretion of BDNF or CNTF affected endogenous retinal gene expression. One year after the intravitreal injection of AAV-green fluorescent protein (GFP), bi-cistronic AAV-BDNF-GFP or AAV-CNTF-GFP, mRNA was extracted and analyzed using custom 96 well polymerase chain reaction arrays. Of 93 test genes, 56% showed significantly altered expression in AAV-BDNF-GFP and/or AAV-CNTF-GFP retinas compared with AAV-GFP controls. Of these genes, 73% showed differential expression in AAV-BDNF versus AAV-CNTF injected eyes. To focus on retinal ganglion cell changes, quantitative polymerase chain reaction was undertaken on mRNA (16 genes) obtained from fixed retinal sections in which the ganglion cell layer was enriched. The sign and extent of fold changes in ganglion cell layer gene expression differed markedly from whole retinal samples. Sustained and global alteration in endogenous mRNA expression after gene therapy should be factored into any interpretation of experimental/clinical outcomes, particularly when introducing factors into the central nervous system that require secretion to evoke functionality.

  5. Differential gene expression profiling of large and small retinal ganglion cells

    PubMed Central

    Ivanov, Dmitry; Dvoriantchikova, Galina; Barakat, David J.; Nathanson, Lubov; Shestopalov, Valery I.

    2014-01-01

    Different sub-populations of retinal ganglion cells (RGCs) vary in their sensitivity to pathological conditions such as retinal ischemia, diabetic retinopathy and glaucoma. Comparative transcriptomic analysis of such groups will likely reveal molecular determinants of differential sensitivity to stress. However, gene expression profiling of primary neuronal sub-populations represent a challenge due to the cellular heterogeneity of retinal tissue. In this manuscript, we report the use of a fluorescent neural tracer to specifically label and selectively isolate RGCs with different soma sizes by fluorescence-activated cell sorting (FACS) for the purpose of differential gene expression profiling. We identified 145 genes that were more active in the large RGCs and 312 genes in the small RGCs. Differential data were validated by quantitative RT-PCR, several corresponding proteins were confirmed by immunohistochemistry. Functional characterization revealed differential activity of genes implicated in synaptic transmission, neurotransmitter secretion, axon guidance, chemotaxis, ion transport and tolerance to stress. An in silico reconstruction of cellular networks suggested that differences in pathway activity between the two sub-populations of RGCs are controlled by networks interconnected by SP-1, Erk2(MAPK1), Egr1, Egr2 and, potentially, regulated via transcription factors C/EBPbeta, HSF1, STAT1- and c-Myc. The results show that FACS-aided purification of retrogradely labeled cells can be effectively utilized for transcriptional profiling of adult retinal neurons. PMID:18640154

  6. A novel mutation in retinitis pigmentosa GTPase regulator gene with a distinctive retinitis pigmentosa phenotype in a Chinese family.

    PubMed

    Sheng, Xunlun; Li, Zili; Zhang, Xinfang; Wang, Jing; Ren, Hongwang; Sun, Yanbo; Meng, Ruihua; Rong, Weining; Zhuang, Wenjuan

    2010-08-15

    To screen the mutation in the retinitis pigmentosa GTPase regulator (RPGR) ORF15 in a large Chinese family with X-linked recessive retinitis pigmentosa and describe the phenotype in affected male and female carriers. Ophthalmic examination was performed on 77 family members to identify affected individuals and to characterize the disease phenotype. PCR and direct sequencing were used for screening mutations in the RPGR gene. Mutation screening demonstrated a novel mutation ORF15+577_578 delAG, which caused an open reading frameshift and resulted in premature truncation of the RPGR protein. The mutation was detected in eight affected male individuals and 14 obligate female carriers of the family and was found to segregate with the phenotype in this family. The mutation led to a severe retinitis pigmentosa (RP) phenotype in male-affected individuals, with some variability in the age of onset of night blindness and visual acuity, but was recessive in female carriers without an RP phenotype. However, the state associated with the carrier was moderate to high myopia with the refractive error ranging from -5.00 D to 22.00 D in 14 female carriers. This novel mutation in RPGR ORF15 causes a serious RP phenotype in males and no RP phenotype in female carriers. Moderate to high myopia was a particular feature for female carriers in this pedigree. Our finding expands the spectrum of RPGR mutations causing X-linked RP and expands phenotypic spectrum of the disease in a Chinese family. This finding will be useful for further genetic consultations and genetic diagnosis.

  7. A novel mutation in retinitis pigmentosa GTPase regulator gene with a distinctive retinitis pigmentosa phenotype in a Chinese family

    PubMed Central

    Zhang, Xinfang; Wang, Jing; Ren, Hongwang; Sun, Yanbo; Meng, Ruihua; Rong, Weining

    2010-01-01

    Purpose To screen the mutation in the retinitis pigmentosa GTPase regulator (RPGR) ORF15 in a large Chinese family with X-linked recessive retinitis pigmentosa and describe the phenotype in affected male and female carriers. Methods Ophthalmic examination was performed on 77 family members to identify affected individuals and to characterize the disease phenotype. PCR and direct sequencing were used for screening mutations in the RPGR gene. Results Mutation screening demonstrated a novel mutation ORF15+577_578 delAG, which caused an open reading frameshift and resulted in premature truncation of the RPGR protein. The mutation was detected in eight affected male individuals and 14 obligate female carriers of the family and was found to segregate with the phenotype in this family. The mutation led to a severe retinitis pigmentosa (RP) phenotype in male-affected individuals, with some variability in the age of onset of night blindness and visual acuity, but was recessive in female carriers without an RP phenotype. However, the state associated with the carrier was moderate to high myopia with the refractive error ranging from −5.00 D to 22.00 D in 14 female carriers. Conclusions This novel mutation in RPGR ORF15 causes a serious RP phenotype in males and no RP phenotype in female carriers. Moderate to high myopia was a particular feature for female carriers in this pedigree. Our finding expands the spectrum of RPGR mutations causing X-linked RP and expands phenotypic spectrum of the disease in a Chinese family. This finding will be useful for further genetic consultations and genetic diagnosis. PMID:20806050

  8. Ethics of Gene Therapy Debated.

    ERIC Educational Resources Information Center

    Borman, Stu

    1991-01-01

    Presented are the highlights of a press conference featuring biomedical ethicist LeRoy Walters of Georgetown University and attorney Andrew Kimbrell of the Foundation on Economic Trends. The opposing points of view of these two speakers serve to outline the pros and cons of the gene therapy issue. (CW)

  9. Ethics of Gene Therapy Debated.

    ERIC Educational Resources Information Center

    Borman, Stu

    1991-01-01

    Presented are the highlights of a press conference featuring biomedical ethicist LeRoy Walters of Georgetown University and attorney Andrew Kimbrell of the Foundation on Economic Trends. The opposing points of view of these two speakers serve to outline the pros and cons of the gene therapy issue. (CW)

  10. Vision from next generation sequencing: Multi-dimensional genome-wide analysis for producing gene regulatory networks underlying retinal development, aging and disease

    PubMed Central

    Yang, Hyun-Jin; Ratnapriya, Rinki; Cogliati, Tiziana; Kim, Jung-Woong; Swaroop, Anand

    2015-01-01

    Genomics and genetics have invaded all aspects of biology and medicine, opening uncharted territory for scientific exploration. The definition of “gene” itself has become ambiguous, and the central dogma is continuously being revised and expanded. Computational biology and computational medicine are no longer intellectual domains of the chosen few. Next generation sequencing (NGS) technology, together with novel methods of pattern recognition and network analyses, has revolutionized the way we think about fundamental biological mechanisms and cellular pathways. In this review, we discuss NGS-based genome-wide approaches that can provide deeper insights into retinal development, aging and disease pathogenesis. We first focus on gene regulatory networks (GRNs) that govern the differentiation of retinal photoreceptors and modulate adaptive response during aging. Then, we discuss NGS technology in the context of retinal disease and develop a vision for therapies based on network biology. We should emphasize that basic strategies for network construction and analyses can be transported to any tissue or cell type. We believe that specific and uniform guidelines are required for generation of genome, transcriptome and epigenome data to facilitate comparative analysis and integration of multi-dimensional data sets, and for constructing networks underlying complex biological processes. As cellular homeostasis and organismal survival are dependent on gene-gene and gene-environment interactions, we believe that network-based biology will provide the foundation for deciphering disease mechanisms and discovering novel drug targets for retinal neurodegenerative diseases. PMID:25668385

  11. Gene therapy for primary immunodeficiencies.

    PubMed

    Thrasher, Adrian J

    2008-05-01

    Primary immunodeficiencies are a group of disorders that are highly amenable to gene therapy because of their defined pathophysiology and the accessibility of the hematopoietic system to molecular intervention. The development of this new therapeutic modality has been driven by the established morbidity and mortality associated with conventional allogeneic stem cell transplantation, particularly in the human leukocyte antigen-mismatched setting. Recently, several clinical studies have shown that gamma retroviral gene transfer technology can produce major beneficial therapeutic effects, but, as for all cellular and pharmacologic treatment approaches, with a finite potential for toxicity. Newer developments in vector design showing promise in overcoming these issues are likely to establish gene therapy as an efficacious strategy for many forms of primary immunodeficiencies.

  12. [Gene therapy and Alzheimer's disease].

    PubMed

    Li, Jian; Li, Wenwen; Zhou, Jun

    2015-04-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the presence of extracellular β-amyloid in the senile plaques, intracellular aggregates of abnormal phosphorylation of tau protein in the neurofibrillary tangles, neuronal loss and cerebrovascular amyloidosis. The manifestations of clinical symptoms include memory impairment, cognitive decline, altered behavior and language deficit. Currently available drugs in AD therapy consist of acetylcholinesterase inhibitors, NMDA receptor antagonists, non-steroidal anti-inflammatory drugs, etc. These drugs can only alleviate the symptoms of AD. Gene therapy is achieved by vector-mediated gene transfer technology, which can delivery DNA or RNA into target cells to promote the expression of a protective or therapeutic protein and silence certain virulence genes.

  13. Safety and Efficacy of Human Wharton's Jelly-Derived Mesenchymal Stem Cells Therapy for Retinal Degeneration

    PubMed Central

    Leow, S. N.; Luu, Chi D.; Hairul Nizam, M. H.; Mok, P. L.; Ruhaslizan, R.; Wong, H. S.; Wan Abdul Halim, Wan Haslina; Ng, M. H.; Ruszymah, B. H. I.; Chowdhury, S. R.; Bastion, M. L. C.; Then, K. Y.

    2015-01-01

    Purpose To investigate the safety and efficacy of subretinal injection of human Wharton’s Jelly-derived mesenchymal stem cells (hWJ-MSCs) on retinal structure and function in Royal College of Surgeons (RCS) rats. Methods RCS rats were divided into 2 groups: hWJ-MSCs treated group (n = 8) and placebo control group (n = 8). In the treatment group, hWJ-MSCs from healthy donors were injected into the subretinal space in one eye of each rat at day 21. Control group received saline injection of the same volume. Additional 3 animals were injected with nanogold-labelled stem cells for in vivo tracking of cells localisation using a micro-computed tomography (microCT). Retinal function was assessed by electroretinography (ERG) 3 days before the injection and repeated at days 15, 30 and 70 after the injection. Eyes were collected at day 70 for histology, cellular and molecular studies. Results No retinal tumor formation was detected by histology during the study period. MicroCT scans showed that hWJ-MSCs stayed localised in the eye with no systemic migration. Transmission electron microscopy showed that nanogold-labelled cells were located within the subretinal space. Histology showed preservation of the outer nuclear layer (ONL) in the treated group but not in the control group. However, there were no significant differences in the ERG responses between the groups. Confocal microscopy showed evidence of hWJ-MSCs expressing markers for photoreceptor, Müller cells and bipolar cells. Conclusions Subretinal injection of hWJ-MSCs delay the loss of the ONL in RCS rats. hWJ-MSCs appears to be safe and has potential to differentiate into retinal-like cells. The potential of this cell-based therapy for the treatment of retinal dystrophies warrants further studies. PMID:26107378

  14. Divergent roles of clock genes in retinal and suprachiasmatic nucleus circadian oscillators.

    PubMed

    Ruan, Guo-Xiang; Gamble, Karen L; Risner, Michael L; Young, Laurel A; McMahon, Douglas G

    2012-01-01

    The retina is both a sensory organ and a self-sustained circadian clock. Gene targeting studies have revealed that mammalian circadian clocks generate molecular circadian rhythms through coupled transcription/translation feedback loops which involve 6 core clock genes, namely Period (Per) 1 and 2, Cryptochrome (Cry) 1 and 2, Clock, and Bmal1 and that the roles of individual clock genes in rhythms generation are tissue-specific. However, the mechanisms of molecular circadian rhythms in the mammalian retina are incompletely understood and the extent to which retinal neural clocks share mechanisms with the suprachiasmatic nucleus (SCN), the central neural clock, is unclear. In the present study, we examined the rhythmic amplitude and period of real-time bioluminescence rhythms in explants of retina from Per1-, Per2-, Per3-, Cry1-, Cry2-, and Clock-deficient mice that carried transgenic PERIOD2::LUCIFERASE (PER2::LUC) or Period1::luciferase (Per1::luc) circadian reporters. Per1-, Cry1- and Clock-deficient retinal and SCN explants showed weakened or disrupted rhythms, with stronger effects in retina compared to SCN. Per2, Per3, and Cry2 were individually dispensable for sustained rhythms in both tissues. Retinal and SCN explants from double knockouts of Cry1 and Cry2 were arrhythmic. Gene effects on period were divergent with reduction in the number of Per1 alleles shortening circadian period in retina, but lengthening it in SCN, and knockout of Per3 substantially shortening retinal clock period, but leaving SCN unaffected. Thus, the retinal neural clock has a unique pattern of clock gene dependence at the tissue level that it is similar in pattern, but more severe in degree, than the SCN neural clock, with divergent clock gene regulation of rhythmic period.

  15. AAV-Mediated CRISPR/Cas Gene Editing of Retinal Cells In Vivo.

    PubMed

    Hung, Sandy S C; Chrysostomou, Vicki; Li, Fan; Lim, Jeremiah K H; Wang, Jiang-Hui; Powell, Joseph E; Tu, Leilei; Daniszewski, Maciej; Lo, Camden; Wong, Raymond C; Crowston, Jonathan G; Pébay, Alice; King, Anna E; Bui, Bang V; Liu, Guei-Sheung; Hewitt, Alex W

    2016-06-01

    Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein (Cas) has recently been adapted to enable efficient editing of the mammalian genome, opening novel avenues for therapeutic intervention of inherited diseases. In seeking to disrupt yellow fluorescent protein (YFP) in a Thy1-YFP transgenic mouse, we assessed the feasibility of utilizing the adeno-associated virus 2 (AAV2) to deliver CRISPR/Cas for gene modification of retinal cells in vivo. Single guide RNA (sgRNA) plasmids were designed to target YFP, and after in vitro validation, selected guides were cloned into a dual AAV system. One AAV2 construct was used to deliver Streptococcus pyogenes Cas9 (SpCas9), and the other delivered sgRNA against YFP or LacZ (control) in the presence of mCherry. Five weeks after intravitreal injection, retinal function was determined using electroretinography, and CRISPR/Cas-mediated gene modifications were quantified in retinal flat mounts. Adeno-associated virus 2-mediated in vivo delivery of SpCas9 with sgRNA targeting YFP significantly reduced the number of YFP fluorescent cells of the inner retina of our transgenic mouse model. Overall, we found an 84.0% (95% confidence interval [CI]: 81.8-86.9) reduction of YFP-positive cells in YFP-sgRNA-infected retinal cells compared to eyes treated with LacZ-sgRNA. Electroretinography profiling found no significant alteration in retinal function following AAV2-mediated delivery of CRISPR/Cas components compared to contralateral untreated eyes. Thy1-YFP transgenic mice were used as a rapid quantifiable means to assess the efficacy of CRISPR/Cas-based retinal gene modification in vivo. We demonstrate that genomic modification of cells in the adult retina can be readily achieved by viral-mediated delivery of CRISPR/Cas.

  16. Gene Therapy Shows Promise for Aggressive Lymphoma

    MedlinePlus

    ... fullstory_163824.html Gene Therapy Shows Promise for Aggressive Lymphoma Over one-third of patients appeared disease- ... 2017 (HealthDay News) -- An experimental gene therapy for aggressive non-Hodgkin lymphoma beat back more than a ...

  17. Controversies in Anticoagulant Therapy in Vitreo-Retinal Surgery.

    PubMed

    Grzybowski, Andrzej; Kupidura-Majewski, Konrad; Kupidura, Paulina

    2015-01-01

    The number of elderly patients using anticoagulant and antiplatelet treatment in prevention of thromboembolism has significantly increased in recent years. It was believed for many years that those patients may be at higher risk for hemorhages during ocular surgery. Different strategies were proposed to prevent these complications, including discontinuation of anticoagulants, dose reduction, or substitution with low molecular weight heparin. The objective of this work was to evaluate the results of studies presenting the results of vitreoretinal surgeries in patients continuing antiplatelet and/or anticoagulant treatment. We performed a PubMed search of possible intraoperative and postoperative hemorrhages in patients receiving anticoagulant and/or antiplatelet therapy during vitreoretinal surgery in 2007-2014. In most of the studies reviewed there was no substantial increase in intraoperative and postoperative hemorrhages risks during vitreoretinal surgery. However, in some studies, a substantially increased risk has been identified. We conclude that the available data is insufficient to decide whether to continue or discontinue anticoagulant and/or antiplatelet therapy during vitreoretinal surgery and we recommend an individualized approach in consultation with the patient's medical doctors and anesthesiologists.

  18. Immune recovery uveitis in AIDS patients with cytomegalovirus retinitis treated with highly active antiretroviral therapy in Venezuela.

    PubMed

    Arevalo, J Fernando; Mendoza, Aristides J; Ferretti, Yolanda

    2003-08-01

    To determine the characteristics of immune recovery uveitis (IRU) in acquired immunodeficiency syndrome (AIDS) patients with inactive cytomegalovirus (CMV) retinitis who responded to highly active antiretroviral therapy (HAART) in a Venezuelan population. We examined 34 patients (50 eyes) with AIDS (HAART responders) and healed CMV retinitis. Patients were observed for a median of 19.3 months following an increase in the CD4 cell count. Ten eyes were treated with sub-Tenon space corticosteroid injections. An age-matched control group of patients with healed CMV retinitis who did not have IRU (30 eyes of 20 patients) was included to compare CMV surface area and complications. We found that 12 (37.5%) of 32 HAART responders developed IRU (18 eyes). The clinical findings of these 18 eyes with IRU are presented. The clinical spectrum of inflammation included vitritis, macular edema, epiretinal membranes, anterior uveitis, macular hole, retinal detachment with proliferative vitreoretinopathy, and cataract. Eyes with IRU had a mean CMV surface area of 31.7%. However, eyes without IRU (control group) had a mean CMV surface area of 35% (P = 0.41). Periocular treatment resulted in vision improvement (in 90% of eyes) without reactivation of retinitis. Symptomatic IRU developed in a significant number of patients with CMV retinitis following successful HAART in a Venezuelan population. CMV surface area does not seem to be a risk factor for the development of IRU. Eyes with IRU respond favorably to antiinflammatory therapy without reactivation of retinitis.

  19. Comparison of intravitreal triamcinolone acetonide with photodynamic therapy and intravitreal bevacizumab with photodynamic therapy for retinal angiomatous proliferation.

    PubMed

    Saito, Masaaki; Shiragami, Chieko; Shiraga, Fumio; Kano, Mariko; Iida, Tomohiro

    2010-03-01

    To compare the efficacy of combined therapy with intravitreal triamcinolone (IVTA) and photodynamic therapy (PDT; IVTA plus PDT) with intravitreal bevacizumab (IVB) and PDT (IVB plus PDT) for patients with retinal angiomatous proliferation (RAP). Retrospective, observational case series. We retrospectively reviewed 25 treatment-naïve eyes of 22 Japanese patients (11 men, 11 women) with retinal angiomatous proliferation. Twelve eyes of 11 patients were treated with combined therapy of IVTA plus PDT from September 1, 2004, through July 31, 2006. Thirteen eyes of 11 patients were treated with combined therapy of IVB plus PDT from February 1, 2007, through January 31, 2008. In 12 eyes treated with IVTA plus PDT, the mean best-corrected visual acuity (BCVA) levels at baseline and 12 months were 0.29 and 0.13, respectively. A significant (P < .05) decline in the mean BCVA from baseline was observed at 12 months. In 13 eyes treated with IVB plus PDT, the mean BCVA levels at baseline and 12 months were 0.25 and 0.37. A significant (P < .05) improvement in the mean BCVA from baseline was observed. At 12 months, the difference in BCVA between the 2 groups was significant (P < .05). The mean numbers of treatments at 12 months in the IVTA plus PDT group and the IVB plus PDT group were 2.7 and 1.6, respectively. The difference between the 2 treatments reached significance (P < .05). No complications developed. Compared with IVTA plus PDT, IVB plus PDT was significantly more effective in maintaining and improving visual acuity and in reducing the number of treatment for patients with retinal angiomatous proliferation. (c) 2010 Elsevier Inc. All rights reserved.

  20. Image Defocus and Altered Retinal Gene Expression in Chick: Clues to the Pathogenesis of Ametropia

    PubMed Central

    McGlinn, Alice M.; Baldwin, Donald A.; Tobias, John W.; Iuvone, P. Michael; Khurana, Tejvir S.

    2011-01-01

    Purpose. Because of the retina's role in refractive development, this study was conducted to analyze the retinal transcriptome in chicks wearing a spectacle lens, a well-established means of inducing refractive errors, to identify gene expression alterations and to develop novel mechanistic hypotheses about refractive development. Methods. One-week-old white Leghorn chicks wore a unilateral spectacle lens of +15 or −15 D for 6 hours or 3 days. With total RNA from the retina/(retinal pigment epithelium, RPE), chicken gene microarrays were used to compare gene expression levels between lens-wearing and contralateral control eyes (n = 6 chicks for each condition). Normalized microarray signal intensities were evaluated by analysis of variance, using a false discovery rate of <10% as the statistical criterion. Selected differentially expressed genes were validated by qPCR. Results. Very few retina/RPE transcripts were differentially expressed after plus lens wear. In contrast, approximately 1300 transcripts were differentially expressed under each of the minus lens conditions, with minimal overlap. For each condition, low fold-changes typified the altered transcriptome. Differentially regulated genes under the minus lens conditions included many potentially informative signaling molecules and genes whose protein products have roles in intrinsic retinal circadian rhythms. Conclusions. Plus or minus lens wear induce markedly different, not opposite, alterations in retina/RPE gene expression. The initial retinal responses to defocus are quite different from those when the eye growth patterns are well established, suggesting that different mechanisms govern the initiation and persistence or progression of refractive errors. The gene lists identify promising signaling candidates and regulatory pathways for future study, including a potential role for circadian rhythms in refractive development. PMID:21642623

  1. Targeted Gene Therapy for Breast Cancer

    DTIC Science & Technology

    2004-06-01

    From the studies performed during the last one year, we determined the effects of AAV-mediated anti-angiogenic gene therapy as a combination therapy...angiogenic gene therapy in combination with chemotherapy. In the next year, we will determine whether such a combination therapy would provide regression of established tumors.

  2. Gene Therapy for Primary Immunodeficiencies

    PubMed Central

    Rivat, Christine; Santilli, Giorgia; Gaspar, H. Bobby

    2012-01-01

    Abstract For over 40 years, primary immunodeficiencies (PIDs) have featured prominently in the development and refinement of human allogeneic hematopoietic stem cell transplantation. More recently, ex vivo somatic gene therapy using autologous cells has provided remarkable evidence of clinical efficacy in patients without HLA-matched stem cell donors and in whom toxicity of allogeneic procedures is likely to be high. Together with improved preclinical models, a wealth of information has accumulated that has allowed development of safer, more sophisticated technologies and protocols that are applicable to a much broader range of diseases. In this review we summarize the status of these gene therapy trials and discuss the emerging application of similar strategies to other PIDs. PMID:22691036

  3. American Society of Gene & Cell Therapy

    MedlinePlus

    ... Join ASGCT! Job Bank Donate Media The American Society of Gene & Cell Therapy The American Society of Gene & Cell Therapy is the primary professional membership organization for gene and cell therapy. The Society's members are scientists, physicians, patient advocates, and other ...

  4. Safe Gene Therapy for Type 1 Diabetes

    DTIC Science & Technology

    2010-10-01

    Safe Gene Therapy for Type 1 Diabetes PRINCIPAL INVESTIGATOR: Massimo Trucco, M.D...4. TITLE AND SUBTITLE Safe Gene Therapy for Type 1 Diabetes New Advanced Technology to Improve Prediction and Prevention 5a. CONTRACT NUMBER...scientific skepticism, the prospect of gene therapy -based treatments remains intriguing and the use of human stem cell research carries with it enor- mous

  5. Gene therapy of benign gynecological diseases☆

    PubMed Central

    Hassan, Memy H.; Othman, Essam E.; Hornung, Daniela; Al-Hendy, Ayman

    2015-01-01

    Gene therapy is the introduction of genetic material into patient’s cells to achieve therapeutic benefit. Advances in molecular biology techniques and better understanding of disease pathogenesis have validated the use of a variety of genes as potential molecular targets for gene therapy based approaches. Gene therapy strategies include: mutation compensation of dysregulated genes; replacement of defective tumor-suppressor genes; inactivation of oncogenes; introduction of suicide genes; immunogenic therapy and antiangiogenesis based approaches. Preclinical studies of gene therapy for various gynecological disorders have not only shown to be feasible, but also showed promising results in diseases such as uterine leiomyomas and endometriosis. In recent years, significant improvement in gene transfer technology has led to the development of targetable vectors, which have fewer side-effects without compromising their efficacy. This review provides an update on developing gene therapy approaches to treat common gynecological diseases such as uterine leiomyoma and endometriosis. PMID:19446586

  6. Eyes open to stem cells: safety trial may pave the way for cell therapy to treat retinal disease in patients

    PubMed Central

    2011-01-01

    A clinical trial using human embryonic stem cell (hESC) therapy for an inherited retinal degenerative disease is about to commence. The Advanced Cell Technology (ACT) trial will treat patients with Stargardt's macular dystrophy using transplanted retinal pigment epithelium derived from hESCs. Currently, no effective treatment is available for Stargardt's disease so a stem cell-based therapy that can slow progression of this blinding condition could represent a significant breakthrough. While there are some hurdles to clear, the ACT trial is a fine example of translational research that could eventually pave the way for a range of stem cell therapies for the retina and other tissues. PMID:22152341

  7. Replication-dependent histone genes are actively transcribed in differentiating and aging retinal neurons.

    PubMed

    Banday, Abdul Rouf; Baumgartner, Marybeth; Al Seesi, Sahar; Karunakaran, Devi Krishna Priya; Venkatesh, Aditya; Congdon, Sean; Lemoine, Christopher; Kilcollins, Ashley M; Mandoiu, Ion; Punzo, Claudio; Kanadia, Rahul N

    2014-01-01

    In the mammalian genome, each histone family contains multiple replication-dependent paralogs, which are found in clusters where their transcription is thought to be coupled to the cell cycle. Here, we wanted to interrogate the transcriptional regulation of these paralogs during retinal development and aging. We employed deep sequencing, quantitative PCR, in situ hybridization (ISH), and microarray analysis, which revealed that replication-dependent histone genes were not only transcribed in progenitor cells but also in differentiating neurons. Specifically, by ISH analysis we found that different histone genes were actively transcribed in a subset of neurons between postnatal day 7 and 14. Interestingly, within a histone family, not all paralogs were transcribed at the same level during retinal development. For example, expression of Hist1h1b was higher embryonically, while that of Hist1h1c was higher postnatally. Finally, expression of replication-dependent histone genes was also observed in the aging retina. Moreover, transcription of replication-dependent histones was independent of rapamycin-mediated mTOR pathway inactivation. Overall, our data suggest the existence of variant nucleosomes produced by the differential expression of the replication-dependent histone genes across retinal development. Also, the expression of a subset of replication-dependent histone isotypes in senescent neurons warrants re-examining these genes as "replication-dependent." Thus, our findings underscore the importance of understanding the transcriptional regulation of replication-dependent histone genes in the maintenance and functioning of neurons.

  8. Orthopedic Gene Therapy in 2008

    PubMed Central

    Evans, Christopher H; Ghivizzani, Steven C; Robbins, Paul D

    2008-01-01

    Orthopedic disorders, although rarely fatal, are the leading cause of morbidity and impose a huge socioeconomic burden. Their prevalence will increase dramatically as populations age and gain weight. Many orthopedic conditions are difficult to treat by conventional means; however, they are good candidates for gene therapy. Clinical trials have already been initiated for arthritis and the aseptic loosening of prosthetic joints, and the development of bone-healing applications is at an advanced, preclinical stage. Other potential uses include the treatment of Mendelian diseases and orthopedic tumors, as well as the repair and regeneration of cartilage, ligaments, and tendons. Many of these goals should be achievable with existing technologies. The main barriers to clinical application are funding and regulatory issues, which in turn reflect major safety concerns and the opinion, in some quarters, that gene therapy should not be applied to nonlethal, nongenetic diseases. For some indications, advances in nongenetic treatments have also diminished enthusiasm. Nevertheless, the preclinical and early clinical data are impressive and provide considerable optimism that gene therapy will provide straightforward, effective solutions to the clinical management of several common debilitating disorders that are otherwise difficult and expensive to treat. PMID:19066598

  9. Photoreceptor Rescue by an Abbreviated Human RPGR Gene in a Murine Model of X-linked Retinitis Pigmentosa

    PubMed Central

    Pawlyk, Basil S.; Adamian, Michael; Sun, Xun; Bulgakov, Oleg V.; Shu, Xinhua; Smith, Alexander J.; Berson, Eliot L.; Ali, Robin R.; Khani, Shahrokh; F.Wright, Alan; Sandberg, Michael A.; Li, Tiansen

    2015-01-01

    The X-linked RP3 gene codes for the ciliary protein RPGR and accounts for over 10% of inherited retinal degenerations. The critical RPGR-ORF15 splice variant contains a highly repetitive purine-rich linker region that renders it unstable and difficult to adapt for gene therapy. To test the hypothesis that the precise length of the linker region is not critical for function, we evaluated whether AAV-mediated replacement gene therapy with a human ORF15 variant containing in-frame shortening of the linker region could reconstitute RPGR function in vivo. We delivered human RPGR-ORF15 replacement genes with deletion of most (314-codons, “short form”) or 1/3 (126-codons, “long form”) of the linker region to Rpgr null mice. Human RPGR-ORF15 expression was detected post-treatment with both forms of ORF15 transgenes. However, only the long form correctly localized to the connecting cilia and led to significant functional and morphological rescue of rods and cones. Thus the highly repetitive region of RPGR is functionally important but that moderate shortening of its length, which confers the advantage of added stability, preserves its function. These findings provide a theoretical basis for optimizing replacement gene design in clinical trials for X-linked RP3. PMID:26348595

  10. Cancer gene therapy: challenges and opportunities.

    PubMed

    Scanlon, Kevin J

    2004-01-01

    Understanding the molecular basis of human disease has been the corner-stone of rationally designed molecular therapies. Medicine has a long history of treating patients with cell therapies (i.e., blood transfusions) and protein therapies (i.e., growth factors and cytokines). Gene therapies are the newest therapeutic strategy for treating human diseases. Where will gene therapy be in five years after the euphoria and frustrations of the last 14 years? This is a complex question, but the primary challenge for gene therapy will be to successfully deliver an efficacious dose of a therapeutic gene to the defective tissue. Will the delivery systems return to the early clinical trials of ex vivo gene therapy or will there still be a high demand for systemic therapy? Will systemic therapy continue to depend on viral vectors, or will non-viral and nano-particles become the new mode for gene delivery? The future success of gene therapy will be built on achievements in other fields, such as medical devices, cell therapy, protein therapy and nano-particle technology. This review describes the advances being made in the gene therapy field, as well as addressing the challenges of the near future for cancer gene therapy.

  11. Leber Hereditary Optic Neuropathy Gene Therapy Clinical Trial Recruitment

    PubMed Central

    Lam, Byron L.; Feuer, William J.; Abukhalil, Fawzi; Porciatti, Vittorio; Hauswirth, William W.; Guy, John

    2011-01-01

    Objective To describe the patient profiles of the Leber hereditary optic neuropathy (LHON) Gene Therapy Clinical Trial, year 1. This study aims to identify and characterize affected patients and carriers with the G11778A mutation in mitochondrial DNA for planned gene therapy that will use “allotopic expression” by delivering a normal nuclear-encoded ND4 gene into the nuclei of retinal ganglion cells via an adeno-associated virus vector injected into the vitreous. Methods Patients with LHON with visual loss as well as asymptomatic maternally related family members were molecularly screened for ND1, ND4, and ND6 mutations in mitochondrial DNA commonly associated with LHON. All patients and maternal relatives also underwent complete neuro-ophthalmic examination, automated visual field testing, pattern electroretinogram (PERG), and OCT3. Results Twenty-five subjects with LHON and 21 carriers positive for the G11778A mitochondrial DNA mutation were recruited. Three additional mutations in the ND4 gene, G11719A, G11947A, or G11914A, were detected. Mean retinal nerve fiber layer (RNFL) thickness was 78.3 μm up to 32 months after visual loss. It was 63.5 μm for all affected patients and 100.7 μm for carriers (P<.01). Mean PERG amplitude was lower in affected patients (40% of normal) than in carriers (94% of normal) (P<.01). Four carriers with PERG amplitudes less than 75% of normal had Early Treatment Diabetic Retinopathy Study acuity more than 20/25, mean defect more than −2 dB, and average RNFL thickness more than 80 μm. Conclusions Potential candidates for future gene therapy may include affected patients, as late as 32 months after loss of vision, with mildly reduced RNFL thickness or carriers with low PERG amplitudes and normal RNFL thickness, if the PERG amplitude is a predictor of conversion to LHON in these carriers. PMID:20837795

  12. A novel start codon mutation of the MERTK gene in a patient with retinitis pigmentosa.

    PubMed

    Jinda, Worapoj; Poungvarin, Naravat; Taylor, Todd D; Suzuki, Yutaka; Thongnoppakhun, Wanna; Limwongse, Chanin; Lertrit, Patcharee; Suriyaphol, Prapat; Atchaneeyasakul, La-Ongsri

    2016-01-01

    Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of inherited retinal degenerations characterized by progressive loss of photoreceptor cells and RPE functions. More than 70 causative genes are known to be responsible for RP. This study aimed to identify the causative gene in a patient from a consanguineous family with childhood-onset severe retinal dystrophy. To identify the defective gene, whole exome sequencing was performed. Candidate causative variants were selected and validated using Sanger sequencing. Segregation analysis of the causative gene was performed in additional family members. To verify that the mutation has an effect on protein synthesis, an expression vector containing the first ten amino acids of the mutant protein fused with the DsRed2 fluorescent protein was constructed and transfected into HEK293T cells. Expression of the fusion protein in the transfected cells was measured using fluorescence microscopy. By filtering against public variant databases, a novel homozygous missense mutation (c.3G>A) localized in the start codon of the MERTK gene was detected as a potentially pathogenic mutation for autosomal recessive RP. The c.3G>A mutation cosegregated with the disease phenotype in the family. No expression of the first ten amino acids of the MerTK mutant fused with the DsRed2 fluorescent protein was detected in HEK293T cells, indicating that the mutation affects the translation initiation site of the gene that may lead to loss of function of the MerTK signaling pathway. We report a novel missense mutation (c.3G>A, p.0?) in the MERTK gene that causes severe vision impairment in a patient. Taken together with previous reports, our results expand the spectrum of MERTK mutations and extend our understanding of the role of the MerTK protein in the pathogenesis of retinitis pigmentosa.

  13. A novel start codon mutation of the MERTK gene in a patient with retinitis pigmentosa

    PubMed Central

    Jinda, Worapoj; Poungvarin, Naravat; Taylor, Todd D.; Suzuki, Yutaka; Thongnoppakhun, Wanna; Limwongse, Chanin; Lertrit, Patcharee; Suriyaphol, Prapat

    2016-01-01

    Purpose Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of inherited retinal degenerations characterized by progressive loss of photoreceptor cells and RPE functions. More than 70 causative genes are known to be responsible for RP. This study aimed to identify the causative gene in a patient from a consanguineous family with childhood-onset severe retinal dystrophy. Methods To identify the defective gene, whole exome sequencing was performed. Candidate causative variants were selected and validated using Sanger sequencing. Segregation analysis of the causative gene was performed in additional family members. To verify that the mutation has an effect on protein synthesis, an expression vector containing the first ten amino acids of the mutant protein fused with the DsRed2 fluorescent protein was constructed and transfected into HEK293T cells. Expression of the fusion protein in the transfected cells was measured using fluorescence microscopy. Results By filtering against public variant databases, a novel homozygous missense mutation (c.3G>A) localized in the start codon of the MERTK gene was detected as a potentially pathogenic mutation for autosomal recessive RP. The c.3G>A mutation cosegregated with the disease phenotype in the family. No expression of the first ten amino acids of the MerTK mutant fused with the DsRed2 fluorescent protein was detected in HEK293T cells, indicating that the mutation affects the translation initiation site of the gene that may lead to loss of function of the MerTK signaling pathway. Conclusions We report a novel missense mutation (c.3G>A, p.0?) in the MERTK gene that causes severe vision impairment in a patient. Taken together with previous reports, our results expand the spectrum of MERTK mutations and extend our understanding of the role of the MerTK protein in the pathogenesis of retinitis pigmentosa. PMID:27122965

  14. In utero and ex vivo Electroporation for Gene Expression in Mouse Retinal Ganglion Cells

    PubMed Central

    Petros, Timothy J; Rebsam, Alexandra; Mason, Carol A

    2009-01-01

    The retina and its sole output neuron, the retinal ganglion cell (RGC), comprise an excellent model in which to examine biological questions such as cell differentiation, axon guidance, retinotopic organization and synapse formation[1]. One drawback is the inability to efficiently and reliably manipulate gene expression in RGCs in vivo, especially in the otherwise accessible murine visual pathways. Transgenic mice can be used to manipulate gene expression, but this approach is often expensive, time consuming, and can produce unwanted side effects. In chick, in ovo electroporation is used to manipulate gene expression in RGCs for examining retina and RGC development. Although similar electroporation techniques have been developed in neonatal mouse pups[2], adult rats[3], and embryonic murine retinae in vitro[4], none of these strategies allow full characterization of RGC development and axon projections in vivo. To this end, we have developed two applications of electroporation, one in utero and the other ex vivo, to specifically target embryonic murine RGCs[5, 6]. With in utero retinal electroporation, we can misexpress or downregulate specific genes in RGCs and follow their axon projections through the visual pathways in vivo, allowing examination of guidance decisions at intermediate targets, such as the optic chiasm, or at target regions, such as the lateral geniculate nucleus. Perturbing gene expression in a subset of RGCs in an otherwise wild-type background facilitates an understanding of gene function throughout the retinal pathway. Additionally, we have developed a companion technique for analyzing RGC axon growth in vitro. We electroporate embryonic heads ex vivo, collect and incubate the whole retina, then prepare explants from these retinae several days later. Retinal explants can be used in a variety of in vitro assays in order to examine the response of electroporated RGC axons to guidance cues or other factors. In sum, this set of techniques enhances

  15. Mutation analysis in 129 genes associated with other forms of retinal dystrophy in 157 families with retinitis pigmentosa based on exome sequencing

    PubMed Central

    Xu, Yan; Guan, Liping; Xiao, Xueshan; Zhang, Jianguo; Li, Shiqiang; Jiang, Hui; Jia, Xiaoyun; Yang, Jianhua; Guo, Xiangming; Yin, Ye; Wang, Jun

    2015-01-01

    Purpose Mutations in 60 known genes were previously identified by exome sequencing in 79 of 157 families with retinitis pigmentosa (RP). This study analyzed variants in 129 genes associated with other forms of hereditary retinal dystrophy in the same cohort. Methods Apart from the 73 genes previously analyzed, a further 129 genes responsible for other forms of hereditary retinal dystrophy were selected based on RetNet. Variants in the 129 genes determined by whole exome sequencing were selected and filtered by bioinformatics analysis. Candidate variants were confirmed by Sanger sequencing and validated by analysis of available family members and controls. Results A total of 90 candidate variants were present in the 129 genes. Sanger sequencing confirmed 83 of the 90 variants. Analysis of family members and controls excluded 76 of these 83 variants. The remaining seven variants were considered to be potential pathogenic mutations; these were c.899A>G, c.1814C>G, and c.2107C>T in BBS2; c.1073C>T and c.1669C>T in INPP5E; and c.3582C>G and c.5704–5C>G in CACNA1F. Six of these seven mutations were novel. The mutations were detected in five unrelated patients without a family history, including three patients with homozygous or compound heterozygous mutations in BBS2 and INPP5E, and two patients with hemizygous mutations in CACNA1F. None of the patients had mutations in the genes associated with autosome dominant retinal dystrophy. Conclusions Only a small portion of patients with RP, about 3% (5/157), had causative mutations in the 129 genes associated with other forms of hereditary retinal dystrophy. PMID:25999675

  16. Gene therapy on demand: site specific regulation of gene therapy.

    PubMed

    Jazwa, Agnieszka; Florczyk, Urszula; Jozkowicz, Alicja; Dulak, Jozef

    2013-08-10

    Since 1990 when the first clinical gene therapy trial was conducted, much attention and considerable promise have been given to this form of treatment. Gene therapy has been used with success in patients suffering from severe combined immunodeficiency syndromes (X-SCID and ADA-deficiency), Leber's congenital amaurosis, hemophilia, β-thalassemia and adrenoleukodystrophy. Last year, the first therapeutic vector (Glybera) for treatment of lipoprotein lipase deficiency has been registered in the European Union. Nevertheless, there are still several numerous issues that need to be improved to make this technique more safe, effective and easily accessible for patients. Introduction of the therapeutic gene to the given cells should provide the level of expression which will restore the production of therapeutic protein to normal values or will provide therapeutic efficacy despite not fully physiological expression. However, in numerous diseases the expression of therapeutic genes has to be kept at certain level for some time, and then might be required to be switched off to be activated again when worsening of the symptoms may aggravate the risk of disease relapse. In such cases the promoters which are regulated by local conditions may be more required. In this article the special emphasis is to discuss the strategies of regulation of gene expression by endogenous stimuli. Particularly, the hypoxia- or miRNA-regulated vectors offer the possibilities of tight but, at the same time, condition-dependent and cell-specific expression. Such means have been already tested in certain pathophysiological conditions. This creates the chance for the translational approaches required for development of effective treatments of so far incurable diseases.

  17. Gene therapy for heart failure.

    PubMed

    Greenberg, Barry

    2017-04-01

    Novel strategies are needed to treat the growing population of heart failure patients. While new drug and device based therapies have improved outcomes over the past several decades, heart failure patients continue to experience amongst the lowest quality of life of any chronic disease, high likelihood of being hospitalized and marked reduction in survival. Better understanding of many of the basic mechanisms involved in the development of heart failure has helped identify abnormalities that could potentially be targeted by gene transfer. Despite success in experimental animal models, translating gene transfer strategies from the laboratory to the clinic remains at an early stage. This review provides an introduction to gene transfer as a therapy for treating heart failure, describes some of the many factors that need to be addressed in order for it to be successful and discusses some of the recent studies that have been carried out in heart failure patients. Insights from these studies highlight both the enormous promise of gene transfer and the obstacles that still need to be overcome for this treatment approach to be successful. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Gene therapy for heart failure.

    PubMed

    Greenberg, Barry

    2015-09-01

    Heart failure is a major public health problem throughout the world and it is likely that its prevalence will continue to grow over the next several decades. Despite advances in the treatment of heart failure, morbidity and mortality remain unacceptably high. Gene transfer therapy provides a novel strategy for targeting abnormalities in cardiac cells that adversely affect cardiac function. New vectors for gene delivery, mainly adeno-associated viruses (AAVs) that are preferentially taken up by cardiomyocytes, can result in sustained transgene expression. The cardiac isoform of sarco(endo)plasmic reticulum Ca(2+)ATPase (SERCA2a) plays a major role in regulating calcium levels in cardiomyocytes. Abnormal calcium handling by the failing heart caused by a reduction in SERCA2a activity adversely affects both systolic and diastolic function. The Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID) study was a Phase 2a double-blind, randomized, placebo-controlled, dose-finding study that was performed in patients with advanced heart failure due to systolic dysfunction. Eligible patients received AAV/SERCA2a or placebo by direct antegrade infusion into the coronary circulation. At the end of 12 months, patients receiving high-dose therapy (i.e. 1×10(13) DNase Resistant Particles) had evidence of favorable changes in several clinically relevant domains compared to patients treated with placebo. There were no safety concerns at any dose of AAV/SERCA2a. Patients treated with AAV/SERCA2a exhibited a striking reduction in cardiovascular events that persisted through 36 months of follow-up compared to patients who received placebo. Transgene expression was detected in the myocardium of patients receiving AAV/SERCA2a gene therapy as long as 31 months after delivery. A second Phase 2b study, CUPID 2, designed to confirm this favorable effect on heart failure events, is currently underway with the results expected to be presented later in

  19. Retinitis Pigmentosa and Bilateral Idiopathic Demyelinating Optic Neuritis in a 6-Year-Old Boy with OFD1 Gene Mutation

    PubMed Central

    Wang, Xun; Zheng, Cong; Liu, Wen

    2017-01-01

    To identify the cause of a sudden binocular vision decrease in patients with retinitis pigmentosa and bilateral idiopathic demyelinating optic neuritis is difficult, but early diagnosis and treatment significantly improve the prognosis. Here, we report a 6-year-old boy with a progressive binocular vision decrease in 38 days. The patient had a history of night blindness, a mottled retina without pigmentation, extinguished electroretinographic response, tritanopia, and an absent ellipsoid zone outside the macula fovea by optical coherence tomography in both eyes. His condition was diagnosed as retinitis pigmentosa (RP) with idiopathic demyelinating optic neuritis (IDON). After corticosteroid therapy, visual acuity recovered to OD: 0.5 and OS: 0.4. Genetic analysis revealed a G985S variant in the oral-facial-digital syndrome 1 gene. Ophthalmologists should pay attention to the existence of other complications in patients with RP who suffer a sudden decrease in vision. A gene survey can help clarify this diagnosis. To our knowledge, this is the first report of a patient with RP and ON, as well as genetic testing results. Nevertheless, the pathogenicity of the variant needs further confirmation. PMID:28191358

  20. In vitro differentiation of adipose-tissue-derived mesenchymal stem cells into neural retinal cells through expression of human PAX6 (5a) gene.

    PubMed

    Rezanejad, Habib; Soheili, Zahra-Soheila; Haddad, Farhang; Matin, Maryam M; Samiei, Shahram; Manafi, Ali; Ahmadieh, Hamid

    2014-04-01

    The neural retina is subjected to various degenerative conditions. Regenerative stem-cell-based therapy holds great promise for treating severe retinal degeneration diseases, although many drawbacks remain to be overcome. One important problem is to gain authentically differentiated cells for replacement. Paired box 6 protein (5a) (PAX6 (5a)) is a highly conserved master control gene that has an essential role in the development of the vertebrate visual system. Human adipose-tissue-derived stem cell (hADSC) isolation was performed by using fat tissues and was confirmed by the differentiation potential of the cells into adipocytes and osteocytes and by their surface marker profile. The coding region of the human PAX6 (5a) gene isoform was cloned and lentiviral particles were propagated in HEK293T. The differentiation of hADSCs into retinal cells was characterized by morphological characteristics, quantitative real-time reverse transcription plus the polymerase chain reaction (qPCR) and immunocytochemistry (ICC) for some retinal cell-specific and retinal pigmented epithelial (RPE) cell-specific markers. hADSCs were successfully isolated. Flow cytometric analysis of surface markers indicated the high purity (~97 %) of isolated hADSCs. After 30 h of post-transduction, cells gradually showed the characteristic morphology of neuronal cells and small axon-like processes emerged. qPCR and ICC confirmed the differentiation of some neural retinal cells and RPE cells. Thus, PAX6 (5a) transcription factor expression, together with medium supplemented with fibronectin, is able to induce the differentiation of hADSCs into retinal progenitors, RPE cells and photoreceptors.

  1. Acute intensive insulin therapy exacerbates diabetic blood-retinal barrier breakdown via hypoxia-inducible factor-1α and VEGF

    PubMed Central

    Poulaki, Vassiliki; Qin, Wenying; Joussen, Antonia M.; Hurlbut, Peter; Wiegand, Stanley J.; Rudge, John; Yancopoulos, George D.; Adamis, Anthony P.

    2002-01-01

    Acute intensive insulin therapy is an independent risk factor for diabetic retinopathy. Here we demonstrate that acute intensive insulin therapy markedly increases VEGF mRNA and protein levels in the retinae of diabetic rats. Retinal nuclear extracts from insulin-treated rats contain higher hypoxia-inducible factor-1α (HIF-1α) levels and demonstrate increased HIF-1α–dependent binding to hypoxia-responsive elements in the VEGF promoter. Blood-retinal barrier breakdown is markedly increased with acute intensive insulin therapy but can be reversed by treating animals with a fusion protein containing a soluble form of the VEGF receptor Flt; a control fusion protein has no such protective effect. The insulin-induced retinal HIF-1α and VEGF increases and the related blood-retinal barrier breakdown are suppressed by inhibitors of p38 mitogen-activated protein kinase (MAPK) and phosphatidylinositol (PI) 3-kinase, but not inhibitors of p42/p44 MAPK or protein kinase C. Taken together, these findings indicate that acute intensive insulin therapy produces a transient worsening of diabetic blood-retinal barrier breakdown via an HIF-1α–mediated increase in retinal VEGF expression. Insulin-induced VEGF expression requires p38 MAPK and PI 3-kinase, whereas hyperglycemia-induced VEGF expression is HIF-1α–independent and requires PKC and p42/p44 MAPK. To our knowledge, these data are the first to identify a specific mechanism for the transient worsening of diabetic retinopathy, specifically blood-retinal barrier breakdown, that follows the institution of intensive insulin therapy. PMID:11901189

  2. Gene Therapy for PRPH2-Associated Ocular Disease: Challenges and Prospects

    PubMed Central

    Conley, Shannon M.; Naash, Muna I.

    2014-01-01

    The peripherin-2 (PRPH2) gene encodes a photoreceptor-specific tetraspanin protein called peripherin-2/retinal degeneration slow (RDS), which is critical for the formation and maintenance of rod and cone outer segments. Over 90 different disease-causing mutations in PRPH2 have been identified, which cause a variety of forms of retinitis pigmentosa and macular degeneration. Given the disease burden associated with PRPH2 mutations, the gene has long been a focus for preclinical gene therapy studies. Adeno-associated viruses and compacted DNA nanoparticles carrying PRPH2 have been successfully used to mediate improvement in the rds−/− and rds+/− mouse models. However, complexities in the pathogenic mechanism for PRPH2-associated macular disease coupled with the need for a precise dose of peripherin-2 to combat a severe haploinsufficiency phenotype have delayed the development of clinically viable genetic treatments. Here we discuss the progress and prospects for PRPH2-associated gene therapy. PMID:25167981

  3. Fine genetic mapping of a gene for autosomal recessive retinitis pigmentosa on chromosome 6p21

    SciTech Connect

    Shugart, Yin Y.; Banerjee, P.; Knowles, J.A.

    1995-08-01

    The inherited retinal degenerations known as retinitis pigmentosa (RP) can be caused by mutations at many different loci and can be inherited as an autosomal recessive, autosomal dominant, or X-linked recessive trait. Two forms of autosomal recessive (arRP) have been reported to cosegregate with mutations in the rhodopsin gene and the beta-subunit of rod phosphodiesterase on chromosome 4p. Genetic linkage has been reported on chromosomes 6p and 1q. In a large Dominican family, we reported an arRp gene near the region of the peripherin/RDS gene. Four recombinations were detected between the disease locus and an intragenic marker derived from peripherin/RDS. 26 refs., 2 figs., 1 tab.

  4. A patient homozygous for the SCA6 gene with retinitis pigmentosa.

    PubMed

    Fukutake, T; Kamitsukasa, I; Arai, K; Hattori, T; Nakajima, T

    2002-05-01

    The present authors studied a 55-year-old-patient homozygous for the SCA6 gene who experienced frequent attacks of positional vertigo at 37 years of age with subsequent staggering gait and night blindness. Retinitis pigmentosa (RP), as well as cerebellar ataxia and vertical antidirectional nystagmus, were detected. The subject's parents were first cousins, and two of his three male cousins, whose parents were also first cousins, had RP without ataxia or nystagmus. The numbers of CAG repeats in the expanded alleles of the SCA6 gene found by molecular analysis were 21 and 21. The genetic results were negative for SCA1, SCA2, SCA3, SCA7 and dentatorubral pallidoluysian atrophy. The retinal degeneration in this patient is most likely to be secondary to a genetic disorder of autosomal or X-linked recessive inheritance rather than SCA6. Other reported cases of patients homozygous for the SCA6 gene are also reviewed.

  5. Mesenchymal stem cell therapy in retinal and optic nerve diseases: An update of clinical trials

    PubMed Central

    Labrador-Velandia, Sonia; Alonso-Alonso, María Luz; Alvarez-Sanchez, Sara; González-Zamora, Jorge; Carretero-Barrio, Irene; Pastor, José Carlos; Fernandez-Bueno, Iván; Srivastava, Girish Kumar

    2016-01-01

    Retinal and optic nerve diseases are degenerative ocular pathologies which lead to irreversible visual loss. Since the advanced therapies availability, cell-based therapies offer a new all-encompassing approach. Advances in the knowledge of neuroprotection, immunomodulation and regenerative properties of mesenchymal stem cells (MSCs) have been obtained by several preclinical studies of various neurodegenerative diseases. It has provided the opportunity to perform the translation of this knowledge to prospective treatment approaches for clinical practice. Since 2008, several first steps projecting new treatment approaches, have been taken regarding the use of cell therapy in patients with neurodegenerative pathologies of optic nerve and retina. Most of the clinical trials using MSCs are in I/II phase, recruiting patients or ongoing, and they have as main objective the safety assessment of MSCs using various routes of administration. However, it is important to recognize that, there is still a long way to go to reach clinical trials phase III-IV. Hence, it is necessary to continue preclinical and clinical studies to improve this new therapeutic tool. This paper reviews the latest progress of MSCs in human clinical trials for retinal and optic nerve diseases. PMID:27928464

  6. Heat shock protein expression as guidance for the therapeutic window of retinal laser therapy

    NASA Astrophysics Data System (ADS)

    Wang, Jenny; Huie, Philip; Dalal, Roopa; Lee, Seungjun; Tan, Gavin; Lee, Daeyoung; Lavinksy, Daniel; Palanker, Daniel

    2016-03-01

    Unlike conventional photocoagulation, non-damaging retinal laser therapy (NRT) limits laser-induced heating to stay below the retinal damage threshold and therefore requires careful dosimetry. Without the adverse effects associated with photocoagulation, NRT can be applied to critical areas of the retina and repeatedly to manage chronic disorders. Although the clinical benefits of NRT have been demonstrated, the mechanism of therapeutic effect and width of the therapeutic window below damage threshold are not well understood. Here, we measure activation of heat shock response via laser-induced hyperthermia as one indication of cellular response. A 577 nm laser is used with the Endpoint Management (EpM) user interface, a titration algorithm, to set experimental pulse energies relative to a barely visible titration lesion. Live/dead staining and histology show that the retinal damage threshold in rabbits is at 40% of titration energy on EpM scale. Heat shock protein 70 (HSP70) expression in the retinal pigment epithelium (RPE) was detected by whole-mount immunohistochemistry after different levels of laser treatment. We show HSP70 expression in the RPE beginning at 25% of titration energy indicating that there is a window for NRT between 25% and 40% with activation of the heat shock protein expression in response to hyperthermia. HSP70 expression is also seen at the perimeter of damaging lesions, as expected based on a computational model of laser heating. Expression area for each pulse energy setting varied between laser spots due to pigmentation changes, indicating the relatively narrow window of non-damaging activation and highlighting the importance of proper titration.

  7. Retinal sensitivity after selective retina therapy (SRT) on patients with central serous chorioretinopathy.

    PubMed

    Yasui, Ayako; Yamamoto, Manabu; Hirayama, Kumiko; Shiraki, Kunihiko; Theisen-Kunde, Dirk; Brinkmann, Ralf; Miura, Yoko; Kohno, Takeya

    2017-02-01

    To assess retinal sensitivity after selective retina therapy (SRT) in patients with central serous chorioretinopathy (CSCR). Seventeen eyes of 17 patients with CSCR lasting longer than 3 months were treated with SRT (wavelength 527 nm Nd: YLF laser, 50-150 μJ/pulse, spot diameter 200 μm). Measurement of best-corrected visual acuity (BCVA), optical coherence tomography, fluorescence angiography, and microperimetry (MAIA™) were conducted before, and 1 and 3 months after treatment. Microperimetry was performed in the central 10° of the macula, and at the test spots applied near the vascular arcade for energy titration. In addition to the treatment effect, all test irradiation spots were thoroughly analyzed with regard to their sensitivity changes. The mean logMAR BCVA had improved from 0.06 to 0.02 after 1 month (p = 0.11) and to 0.03 after 3 months (p = 0.003). Eleven out of 17 eyes (64.7%) showed complete resolution of subretinal fluid after 3 months. Retinal sensitivity in the central 10° increased after 1 month (median: 25.9 dB) and 3 months (26.6 dB) as compared with that before treatment (23.0 dB) (p < 0.001). Analysis of the test spots revealed a slight decrease in retinal sensitivity after 1 month (ΔdB = -0.5 ± 2.1, p = 0.006), while there was no significant difference from baseline after 3 months (ΔdB = -0.3 ± 2.2, p = 0.09). No correlation was found between laser energy and the change in focal retinal sensitivity. Results suggest that SRT is a safe and effective treatment for persistent CSCR and does not leave permanent scotoma regardless of irradiation energy in the therapeutic range.

  8. Subretinal injection of gene therapy vectors and stem cells in the perinatal mouse eye.

    PubMed

    Wert, Katherine J; Skeie, Jessica M; Davis, Richard J; Tsang, Stephen H; Mahajan, Vinit B

    2012-11-25

    The loss of sight affects approximately 3.4 million people in the United States and is expected to increase in the upcoming years.(1) Recently, gene therapy and stem cell transplantations have become key therapeutic tools for treating blindness resulting from retinal degenerative diseases. Several forms of autologous transplantation for age-related macular degeneration (AMD), such as iris pigment epithelial cell transplantation, have generated encouraging results, and human clinical trials have begun for other forms of gene and stem cell therapies.(2) These include RPE65 gene replacement therapy in patients with Leber's congenital amaurosis and an RPE cell transplantation using human embryonic stem (ES) cells in Stargardt's disease.(3-4) Now that there are gene therapy vectors and stem cells available for treating patients with retinal diseases, it is important to verify these potential therapies in animal models before applying them in human studies. The mouse has become an important scientific model for testing the therapeutic efficacy of gene therapy vectors and stem cell transplantation in the eye.(5-8) In this video article, we present a technique to inject gene therapy vectors or stem cells into the subretinal space of the mouse eye while minimizing damage to the surrounding tissue.

  9. Gene therapy for carcinoma of the breast

    PubMed Central

    Stoff-Khalili, MA; Dall, P; Curiel, DT

    2007-01-01

    In view of the limited success of available treatment modalities for breast cancer, alternative and complementary strategies need to be developed. The delineation of the molecular basis of breast cancer provides the possibility of specific intervention by gene therapy through the introduction of genetic material for therapeutic purposes. In this regard, several gene therapy approaches for carcinoma of the breast have been developed. These approaches can be divided into six broad categories: (1) mutation compensation, (2) molecular chemotherapy, (3) proapoptotic gene therapy, (4) antiangiogenic gene therapy, (5) genetic immunopotentiation, and (6) genetic modulation of resistance/sensitivity. Clinical trials for breast cancer have been initiated to evaluate safety, toxicity, and efficacy. Combined modality therapy with gene therapy and chemotherapy or radiation therapy has shown promising results. It is expected that as new therapeutic targets and approaches are identified and advances in vector design are realized, gene therapy will play an increasing role in clinical breast cancer treatment. PMID:16410823

  10. Differential Gene Expression in Explanted Human Retinal Pigment Epithelial Cells 12-Hours Post-Exposure to 532 nm, 120 ps Pulsed Laser Light

    DTIC Science & Technology

    2004-04-01

    years or younger, either sex, with no mitigating ocular or retinal pathology such as glaucoma, diabetic retinopathy, retinitis pigmentosa , etc. Donor: The...USAFA TR 2004-01 Differential Gene Expression in Explanted Human Retinal Pigment Epithelial Cells 12-hours Post-Exposure to 532 nm, 120 ps Pulsed...TR 2004-01 This article, "Differential Gene Expression in Explanted Human Retinal Pigment Epithelial Cells 12-hours Post-Exposure to 532 nm, 120 ps

  11. Advancement and prospects of tumor gene therapy.

    PubMed

    Zhang, Chao; Wang, Qing-Tao; Liu, He; Zhang, Zhen-Zhu; Huang, Wen-Lin

    2011-03-01

    Gene therapy is one of the most attractive fields in tumor therapy. In past decades, significant progress has been achieved. Various approaches, such as viral and non-viral vectors and physical methods, have been developed to make gene delivery safer and more efficient. Several therapeutic strategies have evolved, including gene-based (tumor suppressor genes, suicide genes, antiangiogenic genes, cytokine and oxidative stress-based genes) and RNA-based (antisense oligonucleotides and RNA interference) approaches. In addition, immune response-based strategies (dendritic cell- and T cell-based therapy) are also under investigation in tumor gene therapy. This review highlights the progress and recent developments in gene delivery systems, therapeutic strategies, and possible clinical directions for gene therapy.

  12. In vivo-directed evolution of a new adeno-associated virus for therapeutic outer retinal gene delivery from the vitreous.

    PubMed

    Dalkara, Deniz; Byrne, Leah C; Klimczak, Ryan R; Visel, Meike; Yin, Lu; Merigan, William H; Flannery, John G; Schaffer, David V

    2013-06-12

    Inherited retinal degenerative diseases are a clinically promising focus of adeno-associated virus (AAV)-mediated gene therapy. These diseases arise from pathogenic mutations in mRNA transcripts expressed in the eye's photoreceptor cells or retinal pigment epithelium (RPE), leading to cell death and structural deterioration. Because current gene delivery methods require an injurious subretinal injection to reach the photoreceptors or RPE and transduce just a fraction of the retina, they are suitable only for the treatment of rare degenerative diseases in which retinal structures remain intact. To address the need for broadly applicable gene delivery approaches, we implemented in vivo-directed evolution to engineer AAV variants that deliver the gene cargo to the outer retina after injection into the eye's easily accessible vitreous humor. This approach has general implications for situations in which dense tissue penetration poses a barrier for gene delivery. A resulting AAV variant mediated widespread delivery to the outer retina and rescued the disease phenotypes of X-linked retinoschisis and Leber's congenital amaurosis in corresponding mouse models. Furthermore, it enabled transduction of primate photoreceptors from the vitreous, expanding its therapeutic promise.

  13. Response to aflibercept as secondary therapy in patients with persistent retinal edema due to central retinal vein occlusion initially treated with bevacizumab or ranibizumab.

    PubMed

    Eadie, James A; Ip, Michael S; Kulkarni, Amol D

    2014-12-01

    Recent advances have given practitioners options for the treatment of macular edema secondary to central retinal vein occlusion. These options include steroid injections and implants as well as anti-vascular endothelial growth factor medications. However, there is little in the medical literature to guide secondary therapy when an initial treatment strategy is insufficient. The authors present encouraging results from the treatment of six consecutive cases of central retinal vein occlusion treated with aflibercept as a secondary therapy for macular edema refractory to repeated intravitreal bevacizumab or ranibizumab injections. A retrospective review of six consecutive cases of central retinal vein occlusion with persistent macular edema despite regular anti-vascular endothelial growth factor injections that were transitioned to aflibercept was conducted. Optical coherence tomography and visual acuity data were examined. All six eyes from the six patients included showed either complete or near complete resolution of macular edema with one or two injections of aflibercept. The improvement in edema was accompanied by lasting modest visual gains in three of the six patients and in subjective visual improvement in four of the six patients. The six eyes in this series all responded favorably to aflibercept as a secondary therapy. Although the sample size is too small to draw definitive conclusions, the results are encouraging.

  14. Gene therapy restores vision in a canine model of childhood blindness.

    PubMed

    Acland, G M; Aguirre, G D; Ray, J; Zhang, Q; Aleman, T S; Cideciyan, A V; Pearce-Kelling, S E; Anand, V; Zeng, Y; Maguire, A M; Jacobson, S G; Hauswirth, W W; Bennett, J

    2001-05-01

    The relationship between the neurosensory photoreceptors and the adjacent retinal pigment epithelium (RPE) controls not only normal retinal function, but also the pathogenesis of hereditary retinal degenerations. The molecular bases for both primary photoreceptor and RPE diseases that cause blindness have been identified. Gene therapy has been used successfully to slow degeneration in rodent models of primary photoreceptor diseases, but efficacy of gene therapy directed at photoreceptors and RPE in a large-animal model of human disease has not been reported. Here we study one of the most clinically severe retinal degenerations, Leber congenital amaurosis (LCA). LCA causes near total blindness in infancy and can result from mutations in RPE65 (LCA, type II; MIM 180069 and 204100). A naturally occurring animal model, the RPE65-/- dog, suffers from early and severe visual impairment similar to that seen in human LCA. We used a recombinant adeno-associated virus (AAV) carrying wild-type RPE65 (AAV-RPE65) to test the efficacy of gene therapy in this model. Our results indicate that visual function was restored in this large animal model of childhood blindness.

  15. RPE65 gene therapy slows cone loss in Rpe65-deficient dogs.

    PubMed

    Mowat, F M; Breuwer, A R; Bartoe, J T; Annear, M J; Zhang, Z; Smith, A J; Bainbridge, J W B; Petersen-Jones, S M; Ali, R R

    2013-05-01

    Recent clinical trials of retinal pigment epithelium gene (RPE65) supplementation therapy in Leber congenital amaurosis type 2 patients have demonstrated improvements in rod and cone function, but it may be some years before the effects of therapy on photoreceptor survival become apparent. The Rpe65-deficient dog is a very useful pre-clinical model in which to test efficacy of therapies, because the dog has a retina with a high degree of similarity to that of humans. In this study, we evaluated the effect of RPE65 gene therapy on photoreceptor survival in order to predict the potential benefit and limitations of therapy in patients. We examined the retinas of Rpe65-deficient dogs after RPE65 gene therapy to evaluate the preservation of rods and cone photoreceptor subtypes. We found that gene therapy preserves both rods and cones. While the moderate loss of rods in the Rpe65-deficient dog retina is slowed by gene therapy, S-cones are lost extensively and gene therapy can prevent that loss, although only within the treated area. Although LM-cones are not lost extensively, cone opsin mislocalization indicates that they are stressed, and this can be partially reversed by gene therapy. Our results suggest that gene therapy may be able to slow cone degeneration in patients if intervention is sufficiently early and also that it is probably important to treat the macula in order to preserve central function.

  16. Episomal vectors for gene therapy.

    PubMed

    Ehrhardt, Anja; Haase, Rudolf; Schepers, Aloys; Deutsch, Manuel J; Lipps, Hans Joachim; Baiker, Armin

    2008-06-01

    The increasing knowledge of the molecular and genetic background of many different human diseases has led to the vision that genetic engineering might be used one day for their phenotypic correction. The main goal of gene therapy is to treat loss-of-function genetic disorders by delivering correcting therapeutic DNA sequences into the nucleus of a cell, allowing its long-term expression at physiologically relevant levels. Manifold different vector systems for the therapeutic gene delivery have been described over the recent years. They all have their individual advantages but also their individual limitations and must be judged on a careful risk/benefit analysis. Integrating vector systems can deliver genetic material to a target cell with high efficiency enabling long-term expression of an encoded transgene. The main disadvantage of integrating vector systems, however, is their potential risk of causing insertional mutagenesis. Episomal vector systems have the potential to avoid these undesired side effects, since they behave as separate extrachromosomal elements in the nucleus of a target cell. Within this article we present a comprehensive survey of currently available episomal vector systems for the genetic modification of mammalian cells. We will discuss their advantages and disadvantages and their applications in the context of basic research, biotechnology and gene therapy.

  17. Stem cell directed gene therapy.

    PubMed

    Engel, B C; Kohn, D B

    1999-05-01

    A potential therapeutic approach to HIV-1 infection is the genetic modification of cells of a patient to make them resistant to HIV-1. Hematopoietic stem cells are an attractive target for gene therapy of AIDS because of their ability to generate a broad repertoire of mature T lymphocytes, as well as the monocytic cells (macrophages, dendritic cells and microglia) which are also involved in HIV-1 pathogenesis. A number of synthetic "anti-HIV-1 genes" have been developed which inhibit HIV-1 replication. However, current methods for gene transfer into human hematopoietic stem cells, using retroviral vectors derived from the Moloney murine leukemia virus, have been minimally effective. Clinical trials performed to date in which hematopoietic cells from HIV-1-positive patients have been transduced with retroviral vectors and then reinfused have produced low to undetectable levels of gene-containing peripheral blood leukocytes. New vector delivery systems, such as lentiviral vectors, need to be developed to ensure efficient gene transfer and persistent transgene expression to provide life-long resistance to the cells targeted by HIV-1.

  18. RITONAVIR-ASSOCIATED TOXICITY MIMICKING RETINITIS PIGMENTOSA IN AN HIV-INFECTED PATIENT ON HIGHLY ACTIVE ANTIRETROVIRAL THERAPY.

    PubMed

    Papavasileiou, Evangelia; Younis, Saad; Zygoura, Vasiliki; Quijano, Claudia; Jackson, Timothy L

    2017-01-01

    To report ritonavir-associated retinal pigment epithelium toxicity in a patient infected with the HIV on highly active antiretroviral therapy including ritonavir. Retrospective single case report. The authors describe a case of gradual onset of blurry vision in both eyes in an HIV-positive male. Visual acuity, clinical examination findings, and functional testing (electroretinogram and Goldmann perimetry) were reviewed. Diagnostic imaging, including fundus photography, spectral domain optical coherence tomography, fluorescein angiography, and fundus autofluorescence were assessed. 59-year-old HIV-infected male, treated with ritonavir for eight years, presented with a history of decreased night vision and peripheral field loss. Ophthalmologic examination confirmed the diagnosis of retinal toxicity. Goldmann perimetry showed areas of central and para-central scotomas. Electroretinograms demonstrated mild to moderate photoreceptor dysfunction. Fundus examination revealed a diffuse pattern of retinal pigment epithelium mottling in both eyes. Spectral domain optical coherence tomography confirmed the presence of choroidal thinning, whereas fundus autofluorescence showed mottled hypoautofluorescence. Although ritonavir-associated retinal toxicity is clinically uncommon, the clinical features of our findings support this diagnosis. Consideration of highly active antiretroviral therapy-associated retinal toxicity should be given to the differential diagnosis in HIV-positive patients with retinopathy of unclear etiology. This report also highlights the need for constant monitoring of patients using the ritonavir for early detection of possible retinal toxicity.

  19. In Vivo Fluorescence Retinal Imaging Following AAV2-Mediated Gene Delivery in the Rat Retina.

    PubMed

    Lee, Joo Yong; Hwang, Yoonha; Kim, Ji Hyun; Kim, Yu Sun; Jung, Bok Kyoung; Kim, Pilhan; Lee, Heuiran

    2016-06-01

    The purpose of this study was to evaluate longitudinal gene expression patterns by retinal imaging using a modified custom-built confocal laser-scanning microscope in experimental rats after intravitreal injection of recombinant adeno-associated virus 2 (rAAV2-green fluorescent protein [GFP]). Ten 9-week-old Wistar rats were divided into two groups: experimental group (group 1) that received a rAAV2-GFP intravitreal injection and control group (group 2) that received a vehicle. After anesthesia using a Zoletil intraperitoneal injection, 8 μL rAAV2-GFP in group 1 or vehicle in group 2 was injected intravitreally using a 33-G Hamilton syringe. In vivo fluorescence retinal images were acquired under anesthesia at 2, 4, 6, and 13 days after rAAV or vehicle delivery. Differences in GFP fluorescence were identified starting from day 2 after the intravitreal injection of rAAV2-GFP in group 1. Between days 4 and 6, the intensity and area of fluorescence in the retina began to increase and peaked at day 13. Based on the pattern of GFP expression, the axon of the nerve fiber layer ganglion cell was identified. In group 2, eyes treated with the vehicle showed a small amount of autofluorescence in a limited area for up to 2 weeks, with no increase in intensity during this period. In vivo retinal imaging confirmed gene expression within 2 weeks after the intravitreal injection of rAAV2-GFP. Gene transfer and expression in the rat retina occurs quickly in 2 days and appears to peak within 2 weeks of gene delivery. In vivo retinal imaging may be a useful noninvasive tool to continuously monitor gene expression in the retina over time.

  20. Pseudo-Fovea Formation After Gene Therapy for RPE65-LCA

    PubMed Central

    Cideciyan, Artur V.; Aguirre, Geoffrey K.; Jacobson, Samuel G.; Butt, Omar H.; Schwartz, Sharon B.; Swider, Malgorzata; Roman, Alejandro J.; Sadigh, Sam; Hauswirth, William W.

    2015-01-01

    Purpose. The purpose of this study was to evaluate fixation location and oculomotor characteristics of 15 patients with Leber congenital amaurosis (LCA) caused by RPE65 mutations (RPE65-LCA) who underwent retinal gene therapy. Methods. Eye movements were quantified under infrared imaging of the retina while the subject fixated on a stationary target. In a subset of patients, letter recognition under retinal imaging was performed. Cortical responses to visual stimulation were measured using functional magnetic resonance imaging (fMRI) in two patients before and after therapy. Results. All patients were able to fixate on a 1° diameter visible target in the dark. The preferred retinal locus of fixation was either at the anatomical fovea or at an extrafoveal locus. There were a wide range of oculomotor abnormalities. Natural history showed little change in oculomotor abnormalities if target illuminance was increased to maintain target visibility as the disease progressed. Eleven of 15 study eyes treated with gene therapy showed no differences from baseline fixation locations or instability over an average of follow-up of 3.5 years. Four of 15 eyes developed new pseudo-foveas in the treated retinal regions 9 to 12 months after therapy that persisted for up to 6 years; patients used their pseudo-foveas for letter identification. fMRI studies demonstrated that preservation of light sensitivity was restricted to the cortical projection zone of the pseudo-foveas. Conclusions. The slow emergence of pseudo-foveas many months after the initial increases in light sensitivity points to a substantial plasticity of the adult visual system and a complex interaction between it and the progression of underlying retinal disease. The visual significance of pseudo-foveas suggests careful consideration of treatment zones for future gene therapy trials. (ClinicalTrials.gov number, NCT00481546.) PMID:25537204

  1. Pseudo-fovea formation after gene therapy for RPE65-LCA.

    PubMed

    Cideciyan, Artur V; Aguirre, Geoffrey K; Jacobson, Samuel G; Butt, Omar H; Schwartz, Sharon B; Swider, Malgorzata; Roman, Alejandro J; Sadigh, Sam; Hauswirth, William W

    2014-12-23

    The purpose of this study was to evaluate fixation location and oculomotor characteristics of 15 patients with Leber congenital amaurosis (LCA) caused by RPE65 mutations (RPE65-LCA) who underwent retinal gene therapy. Eye movements were quantified under infrared imaging of the retina while the subject fixated on a stationary target. In a subset of patients, letter recognition under retinal imaging was performed. Cortical responses to visual stimulation were measured using functional magnetic resonance imaging (fMRI) in two patients before and after therapy. All patients were able to fixate on a 1° diameter visible target in the dark. The preferred retinal locus of fixation was either at the anatomical fovea or at an extrafoveal locus. There were a wide range of oculomotor abnormalities. Natural history showed little change in oculomotor abnormalities if target illuminance was increased to maintain target visibility as the disease progressed. Eleven of 15 study eyes treated with gene therapy showed no differences from baseline fixation locations or instability over an average of follow-up of 3.5 years. Four of 15 eyes developed new pseudo-foveas in the treated retinal regions 9 to 12 months after therapy that persisted for up to 6 years; patients used their pseudo-foveas for letter identification. fMRI studies demonstrated that preservation of light sensitivity was restricted to the cortical projection zone of the pseudo-foveas. The slow emergence of pseudo-foveas many months after the initial increases in light sensitivity points to a substantial plasticity of the adult visual system and a complex interaction between it and the progression of underlying retinal disease. The visual significance of pseudo-foveas suggests careful consideration of treatment zones for future gene therapy trials. (ClinicalTrials.gov number, NCT00481546.). Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

  2. Leber Congenital Amaurosis due to RPE65 Mutations and its Treatment with Gene Therapy

    PubMed Central

    Cideciyan, Artur V.

    2010-01-01

    Leber congenital amaurosis (LCA) is a rare hereditary retinal degeneration caused by mutations in more than a dozen genes. RPE65, one of these mutated genes, is highly expressed in the retinal pigment epithelium where it encodes the retinoid isomerase enzyme essential for the production of chromophore which forms the visual pigment in rod and cone photoreceptors of the retina. Congenital loss of chromophore production due to RPE65-deficiency together with progressive photoreceptor degeneration cause severe and progressive loss of vision. RPE65-associated LCA recently gained recognition outside of specialty ophthalmic circles due to early success achieved by three clinical trials of gene therapy using recombinant adeno-associated virus (AAV) vectors. The trials were built on multitude of basic, pre-clinical and clinical research defining the pathophysiology of the disease in human subjects and animal models, and demonstrating the proof-of-concept of gene (augmentation) therapy. Substantial gains in visual function of clinical trial participants provided evidence for physiologically relevant biological activity resulting from a newly introduced gene. This article reviews the current knowledge on retinal degeneration and visual dysfunction in animal models and human patients with RPE65 disease, and examines the consequences of gene therapy in terms of improvement of vision reported. PMID:20399883

  3. Gene expression changes within Müller glial cells in retinitis pigmentosa.

    PubMed

    Roesch, Karin; Stadler, Michael B; Cepko, Constance L

    2012-01-01

    Retinitis pigmentosa (RP) is a progressive retinal degeneration in which the retina loses nearly all of its photoreceptor cells and undergoes major structural changes. Little is known regarding the role the resident glia, the Müller glia, play in the progression of the disease. In this article, we define gene expression changes in Müller glial cells (MGCs) from two different mouse models of RP, the retinal degeneration 1 (rd1) and rhodopsin knockout (Rhod-ko) models. The RNA repertoire of single MGCs was comprehensively profiled, and a comparison was made between MGCs from wild-type (WT) and mutant retinas. Two time points were chosen for analysis, one at the peak of rod photoreceptor death and one during the period of cone photoreceptor death. Retinas were dissociated, and single MGCs were chosen under a dissecting microscope using a micropipette. Single cell cDNAs were generated and genome-wide profiles were obtained by hybridization to Affymetrix arrays. A comparison was made among all samples to discover the changes in gene expression during the periods of rod and cone photoreceptor death. MGCs respond to retinal degeneration by undergoing gliosis, a process marked by the upregulation of glial fibrillary acidic protein (Gfap). Many additional transcripts were found to change. These can be placed into functional clusters, such as retinal remodeling, stress response, and immune-related response. A high degree of heterogeneity among the individual cells was observed, possibly due to their different spatial proximities to dying cells and/or inherent heterogeneity among MGCs.

  4. In Vivo CRISPR/Cas9 Gene Editing Corrects Retinal Dystrophy in the S334ter-3 Rat Model of Autosomal Dominant Retinitis Pigmentosa.

    PubMed

    Bakondi, Benjamin; Lv, Wenjian; Lu, Bin; Jones, Melissa K; Tsai, Yuchun; Kim, Kevin J; Levy, Rachelle; Akhtar, Aslam Abbasi; Breunig, Joshua J; Svendsen, Clive N; Wang, Shaomei

    2016-03-01

    Reliable genome editing via Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 may provide a means to correct inherited diseases in patients. As proof of principle, we show that CRISPR/Cas9 can be used in vivo to selectively ablate the rhodopsin gene carrying the dominant S334ter mutation (Rho(S334)) in rats that model severe autosomal dominant retinitis pigmentosa. A single subretinal injection of guide RNA/Cas9 plasmid in combination with electroporation generated allele-specific disruption of Rho(S334), which prevented retinal degeneration and improved visual function.

  5. In Vivo CRISPR/Cas9 Gene Editing Corrects Retinal Dystrophy in the S334ter-3 Rat Model of Autosomal Dominant Retinitis Pigmentosa

    PubMed Central

    Bakondi, Benjamin; Lv, Wenjian; Lu, Bin; Jones, Melissa K; Tsai, Yuchun; Kim, Kevin J; Levy, Rachelle; Akhtar, Aslam Abbasi; Breunig, Joshua J; Svendsen, Clive N; Wang, Shaomei

    2016-01-01

    Reliable genome editing via Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 may provide a means to correct inherited diseases in patients. As proof of principle, we show that CRISPR/Cas9 can be used in vivo to selectively ablate the rhodopsin gene carrying the dominant S334ter mutation (RhoS334) in rats that model severe autosomal dominant retinitis pigmentosa. A single subretinal injection of guide RNA/Cas9 plasmid in combination with electroporation generated allele-specific disruption of RhoS334, which prevented retinal degeneration and improved visual function. PMID:26666451

  6. Gene therapy in the cornea: 2005--present.

    PubMed

    Mohan, Rajiv R; Tovey, Jonathan C K; Sharma, Ajay; Tandon, Ashish

    2012-01-01

    Successful restoration of vision in human patients with gene therapy affirmed its promise to cure ocular diseases and disorders. The efficacy of gene therapy is contingent upon vector and mode of therapeutic DNA introduction into targeted cells/tissues. The cornea is an ideal tissue for gene therapy due to its ease of access and relative immune-privilege. Considerable progress has been made in the field of corneal gene therapy in last 5 years. Several new gene transfer vectors, techniques and approaches have evolved. Although corneal gene therapy is still in its early stages of development, the potential of gene-based interventions to treat corneal abnormalities has begun to surface. Identification of next generation viral and nanoparticle vectors, characterization of delivered gene levels, localization, and duration in the cornea, and significant success in controlling corneal disorders, particularly fibrosis and angiogenesis, in experimental animal disease models, with no major side effects have propelled gene therapy a step closer toward establishing gene-based therapies for corneal blindness. Recently, researchers have assessed the delivery of therapeutic genes for corneal diseases and disorders due to trauma, infections, chemical, mechanical, and surgical injury, and/or abnormal wound healing. This review provides an update on the developments in gene therapy for corneal diseases and discusses the barriers that hinder its utilization for delivering genes in the cornea.

  7. Gene Therapy in the Cornea: 2005-present

    PubMed Central

    Mohan, Rajiv R.; Tovey, Jonathan C.K.; Sharma, Ajay; Tandon, Ashish

    2011-01-01

    Successful restoration of vision in human patients with gene therapy affirmed its promise to cure ocular diseases and disorders. The efficacy of gene therapy is contingent upon vector and mode of therapeutic DNA introduction into targeted cells/tissues. The cornea is an ideal tissue for gene therapy due to its ease of access and relative immune-privilege. Considerable progress has been made in the field of corneal gene therapy in last 5 years. Several new gene transfer vectors, techniques and approaches have evolved. Although corneal gene therapy is still in its early stages of development, the potential of gene-based interventions to treat corneal abnormalities have begun to surface. Identification of next generation viral and nanoparticle vectors, characterization of delivered gene levels, localization, and duration in the cornea, and significant success in controlling corneal disorders, particularly fibrosis and angiogenesis, in experimental animal disease models, with no major side effects have propelled gene therapy a step closer towards establishing gene-based therapies for corneal blindness. Recently, researchers have assessed the delivery of therapeutic genes for corneal diseases and disorders due to trauma, infections, chemical, mechanical, and surgical injury, and/or abnormal wound healing. This review provides an update on the developments in gene therapy for corneal diseases and discusses the barriers that hinder its utilization for delivering genes in the cornea. PMID:21967960

  8. Progress of mesenchymal stem cell therapy for neural and retinal diseases

    PubMed Central

    Ng, Tsz Kin; Fortino, Veronica R; Pelaez, Daniel; Cheung, Herman S

    2014-01-01

    Complex circuitry and limited regenerative power make central nervous system (CNS) disorders the most challenging and difficult for functional repair. With elusive disease mechanisms, traditional surgical and medical interventions merely slow down the progression of the neurodegenerative diseases. However, the number of neurons still diminishes in many patients. Recently, stem cell therapy has been proposed as a viable option. Mesenchymal stem cells (MSCs), a widely-studied human adult stem cell population, have been discovered for more than 20 years. MSCs have been found all over the body and can be conveniently obtained from different accessible tissues: bone marrow, blood, and adipose and dental tissue. MSCs have high proliferative and differentiation abilities, providing an inexhaustible source of neurons and glia for cell replacement therapy. Moreover, MSCs also show neuroprotective effects without any genetic modification or reprogramming. In addition, the extraordinary immunomodulatory properties of MSCs enable autologous and heterologous transplantation. These qualities heighten the clinical applicability of MSCs when dealing with the pathologies of CNS disorders. Here, we summarize the latest progress of MSC experimental research as well as human clinical trials for neural and retinal diseases. This review article will focus on multiple sclerosis, spinal cord injury, autism, glaucoma, retinitis pigmentosa and age-related macular degeneration. PMID:24772238

  9. Hematopoietic Stem Cell Expansion and Gene Therapy

    PubMed Central

    Watts, Korashon Lynn; Adair, Jennifer; Kiem, Hans-Peter

    2012-01-01

    Hematopoietic stem cell (HSC) gene therapy remains a highly attractive treatment option for many disorders including hematologic conditions, immunodeficiencies including HIV/AIDS, and other genetic disorders like lysosomal storage diseases, among others. In this review, we discuss the successes, side effects, and limitations of current gene therapy protocols. In addition, we describe the opportunities presented by implementing ex vivo expansion of gene-modified HSCs, as well as summarize the most promising ex vivo expansion techniques currently available. We conclude by discussing how some of the current limitations of HSC gene therapy could be overcome by combining novel HSC expansion strategies with gene therapy. PMID:21999373

  10. Form-Deprivation Myopia in Chick Induces Limited Changes in Retinal Gene Expression

    PubMed Central

    McGlinn, Alice M.; Baldwin, Donald A.; Tobias, John W.; Budak, Murat T.; Khurana, Tejvir S.; Stone, Richard A.

    2007-01-01

    Purpose Evidence has implicated the retina as a principal controller of refractive development. In the present study, the retinal transcriptome was analyzed to identify alterations in gene expression and potential signaling pathways involved in form-deprivation myopia of the chick. Methods One-week-old white Leghorn chicks wore a unilateral image-degrading goggle for 6 hours or 3 days (n = 6 at each time). Total RNA from the retina/(retinal pigment epithelium) was used for expression profiling with chicken gene microarrays (Chicken GeneChips; Affymetrix, Santa Clara, CA). To identify gene expression level differences between goggled and contralateral nongoggled eyes, normalized microarray signal intensities were analyzed by the significance analysis of microarrays (SAM) approach. Differentially expressed genes were validated by real-time quantitative reverse transcription–polymerase chain reaction (qPCR) in independent biological replicates. Results Small changes were detected in differentially expressed genes in form-deprived eyes. In chickens that had 6 hours of goggle wear, downregulation of bone morphogenetic protein 2 and connective tissue growth factor was validated. In those with 3 days of goggle wear, downregulation of bone morphogenetic protein 2, vasoactive intestinal peptide, preopro-urotensin II–related peptide and mitogen-activated protein kinase phosphatase 2 was validated, and upregulation of endothelin receptor type B and interleukin-18 was validated. Conclusions Form-deprivation myopia, in its early stages, is associated with only minimal changes in retinal gene expression at the level of the transcriptome. While the list of validated genes is short, each merits further study for potential involvement in the signaling cascade mediating myopia development. PMID:17652709

  11. Improvement and Decline in Vision with Gene Therapy in Childhood Blindness

    PubMed Central

    Jacobson, Samuel G.; Cideciyan, Artur V.; Roman, Alejandro J.; Sumaroka, Alexander; Schwartz, Sharon B.; Heon, Elise; Hauswirth, William W.

    2015-01-01

    Summary Retinal gene therapy for Leber’s congenital amaurosis, an autosomal recessive childhood blindness, has been widely considered to be safe and efficacious. Three years after therapy, improvement in vision was maintained, but the rate of loss of photoreceptors in the treated retina was the same as that in the untreated retina. Here we describe long-term follow-up data from three treated patients. Topographic maps of visual sensitivity in treated regions, nearly 6 years after therapy for two of the patients and 4.5 years after therapy for the third patient, indicate progressive diminution of the areas of improved vision. PMID:25936984

  12. Course of Ocular Function in PRPF31 Retinitis Pigmentosa.

    PubMed

    Hafler, Brian P; Comander, Jason; Weigel DiFranco, Carol; Place, Emily M; Pierce, Eric A

    2016-01-01

    Mutations in pre-mRNA splicing factors are the second most common cause of autosomal dominant retinitis pigmentosa, and a major cause of vision loss. The development of gene augmentation therapy for disease caused by mutations in PRPF31 necessitates defining pretreatment characteristics and disease progression of patients with PRPF31-related retinitis pigmentosa. We show rates of decline of visual field area -6.9% per year and 30-Hz flicker cone response of -9.2% per year, which are both similar to observed rates for retinitis pigmentosa. We hypothesize that RNA splicing factor retinitis pigmentosa will be amenable to treatment by AAV-mediated gene therapy, and that understanding the clinical progression rates of PRPF31 retinitis pigmentosa will help with the design of gene therapy clinical trials.

  13. Gene therapy for bone healing.

    PubMed

    Evans, Christopher H

    2010-06-23

    Clinical problems in bone healing include large segmental defects, spinal fusions, and the nonunion and delayed union of fractures. Gene-transfer technologies have the potential to aid healing by permitting the local delivery and sustained expression of osteogenic gene products within osseous lesions. Key questions for such an approach include the choice of transgene, vector and gene-transfer strategy. Most experimental data have been obtained using cDNAs encoding osteogenic growth factors such as bone morphogenetic protein-2 (BMP-2), BMP-4 and BMP-7, in conjunction with both nonviral and viral vectors using in vivo and ex vivo delivery strategies. Proof of principle has been convincingly demonstrated in small-animal models. Relatively few studies have used large animals, but the results so far are encouraging. Once a reliable method has been developed, it will be necessary to perform detailed pharmacological and toxicological studies, as well as satisfy other demands of the regulatory bodies, before human clinical trials can be initiated. Such studies are very expensive and often protracted. Thus, progress in developing a clinically useful gene therapy for bone healing is determined not only by scientific considerations, but also by financial constraints and the ambient regulatory environment.

  14. Gene therapy for bone healing

    PubMed Central

    Evans, Christopher H.

    2015-01-01

    Clinical problems in bone healing include large segmental defects, nonunion and delayed union of fractures, and spinal fusions. Gene-transfer technologies have the potential to aid healing by permitting the local delivery and sustained expression of osteogenic gene products within osseous lesions. Key questions for such an approach include the choice of transgene, vector and gene-transfer strategy. Most experimental data have been obtained using cDNAs encoding osteogenic growth factors such as bone morphogenetic protein-2 (BMP-2), BMP-4 and BMP-7, in conjunction with both nonviral and viral vectors using in vivo and ex vivo delivery strategies. Proof of principle has been convincingly demonstrated in small-animal models. Relatively few studies have used large animals, but the results so far are encouraging. Once a reliable method has been developed, it will be necessary to perform detailed pharmacological and toxicological studies, as well as satisfy other demands of the regulatory bodies, before human clinical trials can be initiated. Such studies are very expensive and often protracted. Thus, progress in developing a clinically useful gene therapy for bone healing is determined not only by scientific considerations, but also by financial constraints and the ambient regulatory environment. PMID:20569532

  15. Fishing for age-related visual system mutants: behavioral screening of retinal degeneration genes in zebrafish.

    PubMed

    Li, Lei; Li, Yuhao; Chen, Dongyan; Shao, Jinping; Li, Xinle; Xu, Chen

    2010-02-01

    The zebrafish (Danio rerio) has recently become a mainstream model system for genetic studies of human diseases, such as neurological degenerative diseases, heart diseases, immuno-system disorders, etc. In this article, we will review some recent findings of the usefulness of zebrafish as a model vertebrate for behavioral screening of mutations in vertebrate visual system, for example, genes involved in age-related retinal degeneration.

  16. AAV-Mediated Clarin-1 Expression in the Mouse Retina: Implications for USH3A Gene Therapy.

    PubMed

    Dinculescu, Astra; Stupay, Rachel M; Deng, Wen-Tao; Dyka, Frank M; Min, Seok-Hong; Boye, Sanford L; Chiodo, Vince A; Abrahan, Carolina E; Zhu, Ping; Li, Qiuhong; Strettoi, Enrica; Novelli, Elena; Nagel-Wolfrum, Kerstin; Wolfrum, Uwe; Smith, W Clay; Hauswirth, William W

    2016-01-01

    Usher syndrome type III (USH3A) is an autosomal recessive disorder caused by mutations in clarin-1 (CLRN1) gene, leading to progressive retinal degeneration and sensorineural deafness. Efforts to develop therapies for preventing photoreceptor cell loss are hampered by the lack of a retinal phenotype in the existing USH3 mouse models and by conflicting reports regarding the endogenous retinal localization of clarin-1, a transmembrane protein of unknown function. In this study, we used an AAV-based approach to express CLRN1 in the mouse retina in order to determine the pattern of its subcellular localization in different cell types. We found that all major classes of retinal cells express AAV-delivered CLRN1 driven by the ubiquitous, constitutive small chicken β-actin promoter, which has important implications for the design of future USH3 gene therapy studies. Within photoreceptor cells, AAV-expressed CLRN1 is mainly localized at the inner segment region and outer plexiform layer, similar to the endogenous expression of other usher proteins. Subretinal delivery using a full strength viral titer led to significant loss of retinal function as evidenced by ERG analysis, suggesting that there is a critical limit for CLRN1 expression in photoreceptor cells. Taken together, these results suggest that CLRN1 expression is potentially supported by a variety of retinal cells, and the right combination of AAV vector dose, promoter, and delivery method needs to be selected to develop safe therapies for USH3 disorder.

  17. The Pathway From Genes to Gene Therapy in Glaucoma: A Review of Possibilities for Using Genes as Glaucoma Drugs.

    PubMed

    Borrás, Teresa

    2017-01-01

    Treatment of diseases with gene therapy is advancing rapidly. The use of gene therapy has expanded from the original concept of re-placing the mutated gene causing the disease to the use of genes to con-trol nonphysiological levels of expression or to modify pathways known to affect the disease. Genes offer numerous advantages over conventional drugs. They have longer duration of action and are more specific. Genes can be delivered to the target site by naked DNA, cells, nonviral, and viral vectors. The enormous progress of the past decade in molecular bi-ology and delivery systems has provided ways for targeting genes to the intended cell/tissue and safe, long-term vectors. The eye is an ideal organ for gene therapy. It is easily accessible and it is an immune-privileged site. Currently, there are clinical trials for diseases affecting practically every tissue of the eye, including those to restore vision in patients with Leber congenital amaurosis. However, the number of eye trials compared with those for systemic diseases is quite low (1.8%). Nevertheless, judg-ing by the vast amount of ongoing preclinical studies, it is expected that such number will increase considerably in the near future. One area of great need for eye gene therapy is glaucoma, where a long-term gene drug would eliminate daily applications and compliance issues. Here, we review the current state of gene therapy for glaucoma and the possibilities for treating the trabecular meshwork to lower intraocular pressure and the retinal ganglion cells to protect them from neurodegeneration.

  18. Gene therapy for obesity: progress and prospects.

    PubMed

    Gao, Mingming; Liu, Dexi

    2014-06-01

    Advances in understanding the molecular basis of obesity and obesity-associated diseases have made gene therapy a vital approach in coping with this world-wide epidemic. Gene therapy for obesity aims to increase or decrease gene product in favor of lipolysis and energy expenditure, leading toward fat reduction and loss of body weight. It involves successful delivery and expression of therapeutic genes in appropriate cells. The ultimate goal of gene therapy is to restore and maintain energy homeostasis. Here we summarize progress made in recent years in identifying genes responsible for obesity and present examples where the gene therapy approach has been applied to treating or preventing obesity. Discussion on advantages and limitations of gene therapy strategies employed is provided. The intent of this review is to inspire further studies toward the development of new strategies for successful treatment of obesity and obesity-associated diseases.

  19. Gene therapy for allergic diseases.

    PubMed

    Chuang, Ya-Hui; Yang, Yao-Hsu; Wu, Si-Jie; Chiang, Bor-Luen

    2009-06-01

    Allergic diseases, such as allergic asthma, allergic rhinitis, atopic dermatitis, conjunctivitis, urticaria, food allergy, and/or anaphylaxis, are associated with the skewing of immune responses towards a T helper 2 (TH2) phenotype, resulting in eosinophilic inflammation. TH2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13, promote IgE production, mast cell differentiation, and eosinophil growth, migration and activation which then lead to the pathologic abnormalities in allergic diseases. Moreover, the impaired function of regulatory T cells has been noted in allergic diseases. To date, treatments for allergic diseases, such as antihistamines, corticosteroids, bronchodilators and some allergen-specific immunotherapy, are effective but costly and require long-term and recurrent drug administration. Gene therapy has been shown to be an easy, effective, and convenient treatment by delivering the allergen or the therapeutic protein in the form of plasmid DNA in vivo to modulate allergic immune responses. We summarize here the recent advances of gene therapy in allergic diseases and discuss the challenges in clinical application.

  20. Investor Outlook: Significance of the Positive LCA2 Gene Therapy Phase III Results.

    PubMed

    Schimmer, Joshua; Breazzano, Steven

    2015-12-01

    Spark Therapeutics recently reported positive phase III results for SPK-RPE65 targeting the treatment of visual impairment caused by RPE65 gene mutations (often referred to as Leber congenital amaurosis type 2, or LCA2, but may include other retinal disorders), marking an important inflection point for the field of gene therapy. The results highlight the ability to successfully design and execute a randomized trial of a gene therapy and also reinforce the potentially predictive nature of early preclinical and clinical data. The results are expected to pave the way for the first approved gene therapy product in the United States and should sustain investor interest and confidence in gene therapy for many approaches, including retina targeting and beyond.

  1. Improved Intravitreal AAV-Mediated Inner Retinal Gene Transduction after Surgical Internal Limiting Membrane Peeling in Cynomolgus Monkeys.

    PubMed

    Takahashi, Kazuhisa; Igarashi, Tsutomu; Miyake, Koichi; Kobayashi, Maika; Yaguchi, Chiemi; Iijima, Osamu; Yamazaki, Yoshiyuki; Katakai, Yuko; Miyake, Noriko; Kameya, Shuhei; Shimada, Takashi; Takahashi, Hiroshi; Okada, Takashi

    2017-01-04

    The retina is an ideal target for gene therapy because of its easy accessibility and limited immunological response. We previously reported that intravitreally injected adeno-associated virus (AAV) vector transduced the inner retina with high efficiency in a rodent model. In large animals, however, the efficiency of retinal transduction was low, because the vitreous and internal limiting membrane (ILM) acted as barriers to transduction. To overcome these barriers in cynomolgus monkeys, we performed vitrectomy (VIT) and ILM peeling before AAV vector injection. Following intravitreal injection of 50 μL triple-mutated self-complementary AAV serotype 2 vector encoding EGFP, transduction efficiency was analyzed. Little expression of GFP was detected in the control and VIT groups, but in the VIT+ILM group, strong GFP expression was detected within the peeled ILM area. To detect potential adverse effects, we monitored the retinas using color fundus photography, optical coherence tomography, and electroretinography. No serious side effects associated with the pretreatment were observed. These results indicate that surgical ILM peeling before AAV vector administration would be safe and useful for efficient transduction of the nonhuman primate retina and provide therapeutic benefits for the treatment of retinal diseases.

  2. Recent progress in cerebrovascular gene therapy.

    PubMed

    Sato, Naoyuki; Shimamura, Munehisa; Morishita, Ryuichi

    2005-07-01

    Gene therapy provides a potential strategy for the treatment of cardiovascular disease such as peripheral arterial disease, myocardial infarction, restenosis after angioplasty, and vascular bypass graft occlusion. Currently, more than 20 clinical studies of gene therapy for cardiovascular disease are in progress. Although cerebrovascular gene therapy has not proceeded to clinical trials, in contrast to cardiovascular gene therapy, there have been several trials in experimental models. Three major potential targets for cerebrovascular gene therapy are vasospasm after subarachnoid hemorrhage (SAH), ischemic cerebrovascular disease, and restenosis after angioplasty, for which current therapy is often inadequate. In experimental SAH models, strategies using genes encoding a vasodilating protein or decoy oligodeoxynucleotides have been reported to be effective against vasospasm after SAH. In experimental ischemic cerebrovascular disease, gene therapy using growth factors, such as Brain-derived neurotrophic factor (BDNF), Fibroblast growth factor-2 (FGF-2), or Hepatocyte growth factor (HGF), has been reported to be effective for neuroprotection and angiogenesis. Nevertheless, cerebrovascular gene therapy for clinical human treatment still has some problems, such as transfection efficiency and the safety of vectors. Development of an effective and safe delivery system for a target gene will make human cerebrovascular gene therapy possible.

  3. Immunomodulatory gene therapy in lysosomal storage disorders.

    PubMed

    Koeberl, Dwight D; Kishnani, Priya S

    2009-12-01

    Significant advances in therapy for lysosomal storage disorders have occurred with an accelerating pace over the past decade. Although enzyme replacement therapy has improved the outcome of lysosomal storage disorders, antibody responses have occurred and sometimes prevented efficacy, especially in cross-reacting immune material negative patients with Pompe disease. Preclinical gene therapy experiments have revealed the relevance of immune responses to long-term efficacy. The choice of regulatory cassette played a critical role in evading humoral and cellular immune responses to gene therapy in knockout mouse models, at least in adult animals. Liver-specific regulatory cassettes prevented antibody formation and enhanced the efficacy of gene therapy. Regulatory T cells prevented transgene directed immune responses, as shown by adoptive transfer of antigen-specific immune tolerance to enzyme therapy. Immunomodulatory gene therapy with a very low vector dose could enhance the efficacy of enzyme therapy in Pompe disease and other lysosomal storage disorders.

  4. Immunomodulatory gene therapy in lysosomal storage disorders

    PubMed Central

    Koeberl, D.D.; Kishnani, P.S.

    2010-01-01

    Significant advances in therapy for lysosomal storage disorders have occurred with an accelerating pace over the past decade. Although enzyme replacement therapy has improved the outcome of lysosomal storage disorders, antibody responses have occurred and sometimes prevented efficacy, especially in cross-reacting immune material negative patients with Pompe disease. Preclinical gene therapy experiments have revealed the relevance of immune responses to long-term efficacy. The choice of regulatory cassette played a critical role in evading humoral and cellular immune responses to gene therapy in knockout mouse models, at least in adult animals. Liver-specific regulatory cassettes prevented antibody formation and enhanced the efficacy of gene therapy. Regulatory T cells prevented transgene directed immune responses, as shown by adoptive transfer of antigen-specific immune tolerance to enzyme therapy. Immunomodulatory gene therapy with a very low vector dose could enhance the efficacy of enzyme therapy in Pompe disease and other lysosomal storage disorders. PMID:19807648

  5. Targeted Gene Therapy for Breast Cancer

    DTIC Science & Technology

    1998-08-01

    AD AWARD NUMBER DAMD17-97-1-7232 TITLE: Targeted Gene Therapy for Breast Cancer PRINCIPAL INVESTIGATOR: Jinha M. Park CONTRACTING ORGANIZATION...FUNDING NUMBERS Targeted Gene Therapy for Breast Cancer DAMD17-97-1-7232 6. AUTHOR(S) Jinha M. Park 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8...of surface mAb has been internalized by receptor-mediated endocytosis. These mAbs show promise in the specific delivery of gene therapy vectors

  6. Cardiac gene therapy: are we there yet?

    PubMed

    Matkar, P N; Leong-Poi, H; Singh, K K

    2016-08-01

    The incidence of cardiovascular disease (CVD) is increasing throughout the world and is associated with elevated morbidity and mortality. Gene therapy to treat cardiac dysfunction is gaining importance because of the limited therapeutic benefit offered by pharmacotherapies. The growing knowledge of the complex signaling pathways and the development of sophisticated vectors and delivery systems, are facilitating identification and targeting of specific molecular candidates involved in initiation and progression of CVDs. Several preclinical and clinical studies have shown the therapeutic efficiency of gene therapy in different disease models and patients. Hence, gene therapy might plausibly become an unconventional treatment modality for CVD patients. In this review, we summarize the gene delivery carriers, modes of delivery, recent preclinical/clinical studies and potential therapeutic targets. We also briefly discuss the existing limitations of gene therapy, technical challenges surrounding gene carriers and delivery systems, and some approaches to overcome these limitations for bringing CVD gene therapy one step closer to reality.

  7. Update on clinical gene therapy in childhood

    PubMed Central

    Qasim, Waseem; Gaspar, H Bobby; Thrasher, Adrian J

    2007-01-01

    The successful use of gene therapy to correct rare immune system disorders has highlighted the enormous potential of such therapies. We review the current state of gene therapy for childhood immune system disorders, and consider why these conditions have been particularly amenable to genetic correction. As with all emerging therapies, there have been unexpected side effects and their underlying mechanisms are the subject of intense research. Minimising such risks through improved vector design will play an important role in developing the next generation of gene based therapies and extending their applicability. PMID:17954483

  8. Retinal characteristics during 1 year of insulin pump therapy in type 1 diabetes: a prospective, controlled, observational study.

    PubMed

    Klefter, Oliver Niels; Hommel, Eva; Munch, Inger Christine; Nørgaard, Kirsten; Madsbad, Sten; Larsen, Michael

    2016-09-01

    To investigate changes in retinal metabolism, function, structure and morphology in relation to initiation of insulin pump therapy (continuous subcutaneous insulin infusion, CSII). Visual acuity, retinopathy level, dark adaptation kinetics, retinal and subfoveal choroidal thickness, macular perfusion velocities, retinal vessel diameters and blood oxygen saturations were measured at baseline and after 1, 4, 16, 32 and 52 weeks in 31 patients with type 1 diabetes who started CSII and 20 patients who continued multiple daily insulin injections (MDI). One year of CSII reduced haemoglobin A1c (HbA1c ) by 1.6% (17.8 mmol/mol) compared with 0.3% (3.1 mmol/mol) in the MDI group (p < 0.0001). Central retinal thickness increased by 1.5% in the CSII group (within-group p = 0.0098; between-group p = 0.063) without producing macular oedema. No detectable change was found in any other primary outcome measure. The proportion of patients with retinopathy worsening did not differ between groups. At baseline, longer disease duration was associated with higher retinal artery oxygen saturation (p = 0.014) and lower macular venous perfusion velocity (p = 0.045). One year of CSII led to an HbA1c reduction relative to continued MDI and a small increase in retinal thickness but not to early retinopathy worsening or to changes in retinal vascular, structural or functional characteristics. Longer duration of type 1 diabetes appears to be associated with lower macular venous perfusion velocity and higher retinal artery oxygen saturation. The latter could potentially reflect cumulative glycaemia. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  9. Renal-Retinal Ciliopathy Gene Sdccag8 Regulates DNA Damage Response Signaling

    PubMed Central

    Airik, Rannar; Slaats, Gisela G.; Guo, Zhi; Weiss, Anna-Carina; Khan, Naheed; Ghosh, Amiya; Hurd, Toby W.; Bekker-Jensen, Simon; Schrøder, Jacob M.; Elledge, Steve J.; Andersen, Jens S.; Kispert, Andreas; Castelli, Maddalena; Boletta, Alessandra; Giles, Rachel H.

    2014-01-01

    Nephronophthisis-related ciliopathies (NPHP-RCs) are developmental and degenerative kidney diseases that are frequently associated with extrarenal pathologies such as retinal degeneration, obesity, and intellectual disability. We recently identified mutations in a gene encoding the centrosomal protein SDCCAG8 as causing NPHP type 10 in humans. To study the role of Sdccag8 in disease pathogenesis, we generated a Sdccag8 gene-trap mouse line. Homozygous Sdccag8gt/gt mice lacked the wild-type Sdccag8 transcript and protein, and recapitulated the human phenotypes of NPHP and retinal degeneration. These mice exhibited early onset retinal degeneration that was associated with rhodopsin mislocalization in the photoreceptors and reduced cone cell numbers, and led to progressive loss of vision. By contrast, renal histologic changes occurred later, and no global ciliary defects were observed in the kidneys. Instead, renal pathology was associated with elevated levels of DNA damage response signaling activity. Cell culture studies confirmed the aberrant activation of DNA damage response in Sdccag8gt/gt-derived cells, characterized by elevated levels of γH2AX and phosphorylated ATM and cell cycle profile abnormalities. Our analysis of Sdccag8gt/gt mice indicates that the pleiotropic phenotypes in these mice may arise through multiple tissue-specific disease mechanisms. PMID:24722439

  10. Identification of a rhodopsin gene mutation in a large family with autosomal dominant retinitis pigmentosa.

    PubMed

    Yu, Xinping; Shi, Wei; Cheng, Lulu; Wang, Yanfang; Chen, Ding; Hu, Xuting; Xu, Jinling; Xu, Limin; Wu, Yaming; Qu, Jia; Gu, Feng

    2016-01-22

    Retinitis pigmentosa (RP) is a genetically highly heterogeneous retinal disease and one of the leading causes of blindness in the world. Next-generation sequencing technology has enormous potential for determining the genetic etiology of RP. We sought to identify the underlying genetic defect in a 35-year-old male from an autosomal-dominant RP family with 14 affected individuals. By capturing next-generation sequencing (CNGS) of 144 genes associated with retinal diseases, we identified eight novel DNA variants; however, none of them cosegregated for all the members of the family. Further analysis of the CNGS data led to identification of a recurrent missense mutation (c.403C > T, p.R135W) in the rhodopsin (RHO) gene, which cosegregated with all affected individuals in the family and was not observed in any of the unaffected family members. The p.R135W mutation has a reference single nucleotide polymorphism (SNP) ID (rs104893775), and it appears to be responsible for the disease in this large family. This study highlights the importance of examining NGS data with reference SNP IDs. Thus, our study is important for data analysis of NGS-based clinical genetic diagnoses.

  11. Gene based therapies for kidney regeneration.

    PubMed

    Janssen, Manoe J; Arcolino, Fanny O; Schoor, Perry; Kok, Robbert Jan; Mastrobattista, Enrico

    2016-11-05

    In this review we provide an overview of the expanding molecular toolbox that is available for gene based therapies and how these therapies can be used for a large variety of kidney diseases. Gene based therapies range from restoring gene function in genetic kidney diseases to steering complex molecular pathways in chronic kidney disorders, and can provide a treatment or cure for diseases that otherwise may not be targeted. This approach involves the delivery of recombinant DNA sequences harboring therapeutic genes to improve cell function and thereby promote kidney regeneration. Depending on the therapy, the recombinant DNA will express a gene that directly plays a role in the function of the cell (gene addition), that regulates the expression of an endogenous gene (gene regulation), or that even changes the DNA sequence of endogenous genes (gene editing). Some interventions involve permanent changes in the genome whereas others are only temporary and leave no trace. Efficient and safe delivery are important steps for all gene based therapies and also depend on the mode of action of the therapeutic gene. Here we provide examples on how the different methods can be used to treat various diseases, which technologies are now emerging (such as gene repair through CRISPR/Cas9) and what the opportunities, perspectives, potential and the limitations of these therapies are for the treatment of kidney diseases.

  12. A NOVEL LARGE HOMOZYGOUS DELETION IN THE CELLULAR RETINALDEHYDE-BINDING PROTEIN GENE (RLBP1) IN A PATIENT WITH RETINITIS PUNCTATA ALBESCENS.

    PubMed

    Bagheri, Saghar; Pantrangi, Madhulatha; Sodhi, Simrat K; Bagheri, Sayeh; Oellers, Patrick; Scholl, Hendrik P N

    2017-08-18

    To report the phenotypic and genotypic data of a patient with retinitis punctata albescens carrying a novel deletion in the RLBP1 gene. A woman of Iranian descent in her forties with a history of progressive visual deterioration since early childhood exhibited phenotypic features of retinitis punctata albescens with multiple white dots in the posterior pole and macular atrophy in both eyes. The microarray analysis identified a ∼2.160 kb homozygous deletion corresponding to a minimum deletion boundary of chr15q26.1:89,756,882-89,759,041/GRCh37 (hg19), which encompasses exon 6 of the RLBP1 gene. We describe a novel large homozygous deletion in the RLBP1 gene encoding the cellular retinaldehyde-binding protein in a patient of Iranian descent with retinitis punctata albescens. Genotype-phenotype studies may provide more information about the functions of the RLBP1 encoding proteins and the disease course, because RLBP1 mutations are associated with high phenotypic variability and are therefore a necessity for future tailored individual therapies.

  13. Loss of heterozygosity for the NF2 gene in retinal and optic nerve lesions of patients with neurofibromatosis 2

    PubMed Central

    Chan, Chi-Chao; Koch, Christian A; Kaiser-Kupfer, Muriel I; Parry, Dilys M; Gutmann, David H; Zhuang, Zhengping; Vortmeyer, Alexander O

    2008-01-01

    Individuals affected with the neurofibromatosis 2 (NF2) cancer predisposition syndrome develop specific ocular lesions. To determine whether these lesions result from altered NF2 gene expression, microdissection and PCR were used to investigate 40 ocular lesions from seven eyes of four NF2 patients for LOH, with markers that flank the NF2 gene on chromosome 22q. NF2 protein (merlin) expression was also evaluated in these lesions, using immunohistochemistry. Retinal hamartoma was observed in all seven eyes, including one with combined pigment epithelial and retinal hamartoma (CPERH). Retinal tufts were present in four eyes (three patients), retinal dysplasia in two eyes (two patients), optic nerve neurofibroma in one eye, iris naevoid hyperplasia in two eyes (two patients) and pseudophakia in all eyes. Markers were informative in three patients (six eyes from three unrelated families). One patient was non-informative due to prolonged decalcification. All retinal and optic nerve, but not iris lesions, demonstrated consistent LOH for the NF2 gene. Merlin was not expressed in the retina, optic nerve, or iris lesions. These results suggest that inactivation of the NF2 gene is associated with the formation of a variety of retinal and optic nerve lesions in NF2 patients. PMID:12210058

  14. Gene therapy returns to centre stage.

    PubMed

    Naldini, Luigi

    2015-10-15

    Recent clinical trials of gene therapy have shown remarkable therapeutic benefits and an excellent safety record. They provide evidence for the long-sought promise of gene therapy to deliver 'cures' for some otherwise terminal or severely disabling conditions. Behind these advances lie improved vector designs that enable the safe delivery of therapeutic genes to specific cells. Technologies for editing genes and correcting inherited mutations, the engagement of stem cells to regenerate tissues and the effective exploitation of powerful immune responses to fight cancer are also contributing to the revitalization of gene therapy.

  15. Gene therapy for ocular diseases meditated by ultrasound and microbubbles (Review)

    PubMed Central

    WAN, CAIFENG; LI, FENGHUA; LI, HONGLI

    2015-01-01

    The eye is an ideal target organ for gene therapy as it is easily accessible and immune-privileged. With the increasing insight into the underlying molecular mechanisms of ocular diseases, gene therapy has been proposed as an effective approach. Successful gene therapy depends on efficient gene transfer to targeted cells to prove stable and prolonged gene expression with minimal toxicity. At present, the main hindrance regarding the clinical application of gene therapy is not the lack of an ideal gene, but rather the lack of a safe and efficient method to selectively deliver genes to target cells and tissues. Ultrasound-targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene- and drug delivery. When gene-loaded microbubbles are injected, UTMD is able to enhance the transport of the gene to the targeted cells. High-amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane. Thereby, the efficiency of gene therapy can be significantly improved. The UTMD-mediated gene delivery system has been widely used in pre-clinical studies to enhance gene expression in a site-specific manner in a variety of organs. With reasonable application, the effects of sonoporation can be spatially and temporally controlled to improve localized tissue deposition of gene complexes for ocular gene therapy applications. In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood-retinal barrier with no significant side effects. The present review discusses the current status of gene therapy of ocular diseases as well as studies on gene therapy of ocular diseases meditated by UTMD. PMID:26151686

  16. Towards gene therapy for deafness.

    PubMed

    Di Domenico, Marina; Ricciardi, Carmela; Martone, Tiziana; Mazzarella, Nicoletta; Cassandro, Claudia; Chiarella, Giuseppe; D'Angelo, Luigi; Cassandro, Ettore

    2011-10-01

    Many hearing disorders are associated with the damage or loss of sensory hair cells (HC) which can produce a profound and irreversible deafness. Apoptosis pathway is reported to play an important role leading to rapid expansion of the HC lesion after exposure to intense noise. Furthermore, progress made over the last year in understanding molecular mechanisms involved in the proliferative and regenerative capacity of sensory cells in the mammalian inner ear has raised the possibility that targeted therapies might prevent the loss of these cells and preserve the patient's hearing. A first step towards the successful therapeutic exploitation is a better understanding of the different pathways that control survival and proliferation of sensory cells. In this review, we provide an overview of recent findings concerning the possibility to prevent apoptosis in auditory cells. We also show the current knowledge on the molecular mechanisms involved in the potential regenerative behavior of these cells and the progress of gene therapy to prevent deafness noise-induced.

  17. NGS-based Molecular diagnosis of 105 eyeGENE(®) probands with Retinitis Pigmentosa.

    PubMed

    Ge, Zhongqi; Bowles, Kristen; Goetz, Kerry; Scholl, Hendrik P N; Wang, Feng; Wang, Xinjing; Xu, Shan; Wang, Keqing; Wang, Hui; Chen, Rui

    2015-12-15

    The National Ophthalmic Disease Genotyping and Phenotyping Network (eyeGENE(®)) was established in an effort to facilitate basic and clinical research of human inherited eye disease. In order to provide high quality genetic testing to eyeGENE(®)'s enrolled patients which potentially aids clinical diagnosis and disease treatment, we carried out a pilot study and performed Next-generation sequencing (NGS) based molecular diagnosis for 105 Retinitis Pigmentosa (RP) patients randomly selected from the network. A custom capture panel was designed, which incorporated 195 known retinal disease genes, including 61 known RP genes. As a result, disease-causing mutations were identified in 52 out of 105 probands (solving rate of 49.5%). A total of 82 mutations were identified, and 48 of them were novel. Interestingly, for three probands the molecular diagnosis was inconsistent with the initial clinical diagnosis, while for five probands the molecular information suggested a different inheritance model other than that assigned by the physician. In conclusion, our study demonstrated that NGS target sequencing is efficient and sufficiently precise for molecular diagnosis of a highly heterogeneous patient cohort from eyeGENE(®).

  18. Retinal Gene Expression Changes Related to IOP Exposure and Axonal Loss in DBA/2J Mice

    PubMed Central

    Panagis, Lambros; Zhao, Xiujun; Ge, Yongchao; Ren, Lizhen; Mittag, Thomas W.

    2011-01-01

    Purpose. To determine the effects of cumulative IOP exposure and axonal damage on retinal gene expression in DBA/2 mice. Methods. DBA/2J, DBA/2Jpe (pearl), and C57BL/6 mice from 3 to 12 months of age were used. IOP was measured with a rebound tonometer, and optic nerve (ON) damage was determined by grading of ON sections. Retinal RNA was subjected to microarray analysis. Comparisons explored the effects of cumulative IOP exposure (cIOPx) as well as ON damage (ONd) in the DBA/2J animals compared with that in the C57BL/6 and pearl mice. RT-PCR was performed to confirm some of the genes and bioinformatic analysis to identify affected gene networks. Results. Microarrays revealed that an increasing number of genes were up- or downregulated in 9- and 12-month DBA/2J mice with various degrees of ONd. A smaller number of genes were expressed differentially between eyes with different cIOPx at the same age, from 6 months on. Expression of 1385 and 1133 genes differed between DBA/2J animals and C57BL/6 or pearl mice, respectively, and some them were confirmed by RT-PCR. Bioinformatics analysis identified functional gene networks, including members of the complement system, that appeared to be related to cIOPx, ONd, or both. Conclusions. Gene expression changes occur in retinas of DBA/2 mice with various amounts of cIOPx as well as ONd. Genes involved, code for proteins with diverse cellular functions and include among others the complement system. cIOPx and ONd affect common as well as unique gene sets. PMID:21908583

  19. Tyrosine triple mutated AAV2-BDNF gene therapy in a rat model of transient IOP elevation

    PubMed Central

    Igarashi, Tsutomu; Kobayashi, Maika; Kameya, Shuhei; Fujimoto, Chiaki; Nakamoto, Kenji; Takahashi, Hisatomo; Igarashi, Toru; Miyake, Noriko; Iijima, Osamu; Hirai, Yukihiko; Shimada, Takashi; Okada, Takashi; Takahashi, Hiroshi

    2016-01-01

    Purpose We examined the neuroprotective effects of exogenous brain-derived neurotrophic factor (BDNF), which provides protection to retinal ganglion cells (RGCs) in rodents, in a model of transient intraocular pressure (IOP) elevation using a mutant (triple Y-F) self-complementary adeno-associated virus type 2 vector encoding BDNF (tm-scAAV2-BDNF). Methods The tm-scAAV2-BDNF or control vector encoding green fluorescent protein (GFP; tm-scAAV2-GFP) was intravitreally administered to rats, which were then divided into four groups: control, ischemia/reperfusion (I/R) injury only, I/R injury with tm-scAAV2-GFP, and tm-scAAV2-BDNF. I/R injury was then induced by transiently increasing IOP, after which the rats were euthanized to measure the inner retinal thickness and cell counts in the RGC layer. Results Intravitreous injection of tm-scAAV2-BDNF resulted in high levels of BDNF expression in the neural retina. Histological analysis showed that the inner retinal thickness and cell numbers in the RGC layer were preserved after transient IOP elevation in eyes treated with tm-scAAV2-BDNF but not in the other I/R groups. Significantly reduced glial fibrillary acidic protein (GFAP) immunostaining after I/R injury in the rats that received tm-scAAV2-BDNF indicated reduced retinal stress, and electroretinogram (ERG) analysis confirmed preservation of retinal function in the tm-scAAV2-BDNF group. Conclusions These results demonstrate the feasibility and effectiveness of neuroprotective gene therapy using tm-scAAV2-BDNF to protect the inner retina from transiently high intraocular pressure. An in vivo gene therapeutic approach to the clinical management of retinal diseases in conditions such as glaucoma, retinal artery occlusion, hypertensive retinopathy, and diabetic retinopathy thus appears feasible. PMID:27440998

  20. Clinical outcome after switching therapy from ranibizumab and/or bevacizumab to aflibercept in central retinal vein occlusion.

    PubMed

    Pfau, Maximilian; Fassnacht-Riederle, Heidi; Becker, Matthias D; Graf, Nicole; Michels, Stephan

    2015-01-01

    After 48 months, unresolved macular edema secondary to central retinal vein occlusion (CRVO) is present in more than half of the patients treated with ranibizumab/bevacizumab. Switching therapy to aflibercept, a more recent vascular endothelial growth factor-A (VEGF-A) inhibitor, as well as VEGF-B and placental growth factor inhibitor, might improve the clinical outcome in patients with CRVO who respond insufficiently to ranibizumab/bevacizumab. The presented study is a retrospective analysis of CRVO patients (n = 13) responding insufficiently to ranibizumab and/or bevacizumab (requiring treatment every 6 weeks or more frequently). Treatment in these patients was switched to aflibercept, which was administered based on a 'treat and extend' regime. The injection interval, relapse-free interval, central retinal thickness, central retinal volume, visual acuity, and intraocular pressure (IOP) were evaluated prior to switching to aflibercept and at month 6 and year 1 after switching therapy. From baseline to year 1 after switching therapy to aflibercept, the mean injection interval (primary end point) increased by 0.51 months (p = 0.023) and the relapse-free interval by 3.02 weeks (p = 0.003). The mean central retinal thickness decreased by 195.84 µm and the mean central retinal volume (6 mm diameter) by -1.81 mm3 (p = 0.007). Correspondingly, the mean ETDRS score increased from 66.15 at baseline to 76.54 letters at year 1 after switching therapy to aflibercept (+10.38 letters, p = 0.021). The IOP was not statistically significantly affected (-1.2 mm Hg, p = 0.196). Switching therapy from intravitreal ranibizumab/bevacizumab to aflibercept in insufficiently responding macular edema secondary to CRVO elongates the injection interval and the relapse-free interval and provides an improved anatomical as well as functional outcome. © 2015 S. Karger AG, Basel.

  1. Comparison of treatment regimens for cytomegalovirus retinitis in patients with AIDS in the era of highly active antiretroviral therapy.

    PubMed

    Jabs, Douglas A; Ahuja, Alka; Van Natta, Mark; Dunn, J P; Yeh, Steven

    2013-06-01

    To describe the outcomes of different treatment approaches for cytomegalovirus (CMV) retinitis in the era of highly active antiretroviral therapy (HAART). Prospective cohort study, the Longitudinal Study of the Ocular Complications of AIDS. A total of 250 patients with CMV retinitis and a CD4+ T-cell count <100 cells/μl (n = 221) at enrollment or incident retinitis (n = 29) during cohort follow-up. The effects of systemic therapy (vs. intraocular therapy only) on systemic outcomes and the effect of intraocular therapies (ganciclovir implants, intravitreal injections) on ocular outcomes were evaluated. Mortality, CMV dissemination, retinitis progression, and treatment side effects. Regimens containing systemic anti-CMV therapy were associated with a 50% reduction in mortality (adjusted hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.3-0.7; P = 0.006), a 90% reduction in new visceral CMV disease (adjusted HR, 0.1; 95% CI, 0.04-0.4; P = 0.004), and among those with unilateral CMV retinitis at presentation, an 80% reduction in second eye disease (adjusted HR, 0.2; 95% CI, 0.1-0.5; P = 0.0005) when compared with those using only intraocular therapy (implants or injections). Compared with systemic treatment only, regimens containing intravitreal injections had greater rates of retinitis progression (adjusted HR, 3.4; P = 0.004) and greater visual field loss (for loss of one half of the normal field, adjusted HR, 5.5; P < 0.01). Intravitreal implants were not significantly better than systemic therapy (adjusted HR for progression, 0.5; P = 0.26; adjusted HR for loss of one half of the visual field, 0.5; P = 0.45), but the sample size was small. Hematologic and renal side effect rates were similar between those groups with and without systemic anti-CMV therapy. The rate of endophthalmitis was 0.017 per eye-year (EY) (95% CI, 0.006-0.05) among those treated with intravitreal injections and 0.01 per EY (95% CI, 0.002-0.04) among those treated with an implant. In the

  2. Approaches to mitochondrial gene therapy.

    PubMed

    D'Souza, Gerard G M; Weissig, Volkmar

    2004-09-01

    Since their discovery during the end of the 80's the number of diseases found to be associated with defects in the mitochondrial genome has grown significantly. Organs affected by mutations in mitochondrial DNA (mtDNA) include in decreasing order of vulnerability the brain, skeletal muscle, heart, kidney and liver. Hence neuromuscular and neurodegenerative diseases represent the two largest groups of mtDNA diseases. Despite major advances in understanding mtDNA defects at the genetic and biochemical level, there is however no satisfactory treatment available to the vast majority of patients. This is largely due to the fact that most of these patients have respiratory chain defects, i.e. defects that involve the final common pathway of oxidative metabolism, making it impossible to bypass the defect by administering alternative metabolic carriers of energy. Conventional biochemical treatment having reached an impasse, the exploration of gene therapeutic approaches for patients with mtDNA defects is warranted. For now mitochondrial gene therapy appears to be only theoretical and speculative. Any possibility for gene replacement is dependent on the development of an efficient mitochondrial transfection vector. In this review we describe the current state of the development of mitochondria-specific DNA delivery systems. We summarize our own efforts in exploring the properties of dequalinium and other similar cationic bolaamphiphiles with delocalized charge centers, for the design of a vector suited for the transport of DNA to mitochondria in living cells. Further, we outline some unique hurdles that need to be overcome if the development of such delivery systems is to progress.

  3. Gene therapy oversight: lessons for nanobiotechnology.

    PubMed

    Wolf, Susan M; Gupta, Rishi; Kohlhepp, Peter

    2009-01-01

    Oversight of human gene transfer research ("gene therapy") presents an important model with potential application to oversight of nanobiology research on human participants. Gene therapy oversight adds centralized federal review at the National Institutes of Health's Office of Biotechnology Activities and its Recombinant DNA Advisory Committee to standard oversight of human subjects research at the researcher's institution (by the Institutional Review Board and, for some research, the Institutional Biosafety Committee) and at the federal level by the Office for Human Research Protections. The Food and Drug Administration's Center for Biologics Evaluation and Research oversees human gene transfer research in parallel, including approval of protocols and regulation of products. This article traces the evolution of this dual oversight system; describes how the system is already addressing nanobiotechnology in gene transfer: evaluates gene therapy oversight based on public opinion, the literature, and preliminary expert elicitation; and offers lessons of the gene therapy oversight experience for oversight of nanobiotechnology.

  4. Current status of gene therapy for cancer.

    PubMed

    Walther, Wolfgang; Schlag, Peter M

    2013-11-01

    In recent years, remarkable progress has been made in the development of cancer gene therapy into an applicable treatment modality for immunogene, suicide, gene correction and oncolytic therapies. New exciting developments for gene suppression or miRNA therapies are under way. The efforts are focused on more efficient and specific attack at known and novel targets, improvement of vector delivery and therapeutic efficacy. In this review, promising and new gene therapy approaches and clinical studies are briefly discussed to highlight important future directions of preclinical and clinical efforts. Apart from progress for vector development and even more important, improvements for suicide, T-cell-based, oncolytic virus therapies were achieved. In addition, new emerging therapies are successfully developed, which are particularly promising for siRNA-based technologies applied to gene suppression therapy. Novel approaches, such as transcription factor ODN-based decoy, complement the spectrum of current cancer gene therapy. In summary, cancer gene therapy has made remarkable progress in the improvement/refinement of existing strategies and delivery systems. The field is moving toward a therapeutic option, which will also be applicable for the treatment of disseminated metastases. Furthermore, numerous new approaches are about to be translated in clinical trials.

  5. Tissue response to micropulse modulation in retinal laser therapy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wang, Jenny; Quan, Yi; Dalal, Roopa; Palanker, Daniel V.

    2017-02-01

    Micropulse modulation in retinal laser therapy was intended to confine tissue heating around the light-absorbing layers, such as RPE and choroid, while the transparent retina is heated less as a result of slow heat diffusion. Current implementations use micropulses of 100-300μs at 500Hz, with overall pulse envelope of 100-300ms. The effect of such modulation compared to continuous-wave (CW) is not well characterized and misleading comparisons are made in the literature between exposures of different average power or overall duration. In this study, we modeled and measured the retinal tissue response to pulse trains with duty cycles from 4% (80μs pulse at 500Hz) to CW at overall envelope of 200ms and 20ms. Three thresholds of tissue response were measured in Dutch-belted rabbits: immediate (<3s after laser delivery) and delayed (1-5min) ophthalmoscopic visibility of lesions corresponding to photoreceptor damage, as well as fluorescein angiography visibility indicating RPE damage. Both the model and experimental results show that tissue response to micropulse modulation with long pulse envelope (200ms) is not significantly different from CW exposures at the same average power and duration. Heat confinement is improved with lower duty cycle (2%) and shorter pulse envelope (20ms), however further decrease in exposure duration raises the temperature dangerously close to vaporization. Pulse modulation cannot improve the therapeutic range of non-damaging thermal therapy since it is defined by the Arrhenius integral, regardless of the time course of hyperthermia. However, it does allow greater thermal stress to the RPE and underlying choroid while avoiding damage to neural retina.

  6. Gene expression changes in the retina following subretinal injection of human neural progenitor cells into a rodent model for retinal degeneration

    PubMed Central

    Jones, Melissa K.; Lu, Bin; Saghizadeh, Mehrnoosh

    2016-01-01

    Purpose Retinal degenerative diseases (RDDs) affect millions of people and are the leading cause of vision loss. Although treatment options for RDDs are limited, stem and progenitor cell–based therapies have great potential to halt or slow the progression of vision loss. Our previous studies have shown that a single subretinal injection of human forebrain derived neural progenitor cells (hNPCs) into the Royal College of Surgeons (RCS) retinal degenerate rat offers long-term preservation of photoreceptors and visual function. Furthermore, neural progenitor cells are currently in clinical trials for treating age-related macular degeneration; however, the molecular mechanisms of stem cell–based therapies are largely unknown. This is the first study to analyze gene expression changes in the retina of RCS rats following subretinal injection of hNPCs using high-throughput sequencing. Methods RNA-seq data of retinas from RCS rats injected with hNPCs (RCShNPCs) were compared to sham surgery in RCS (RCSsham) and wild-type Long Evans (LEsham) rats. Differential gene expression patterns were determined with in silico analysis and confirmed with qRT-PCR. Function, biologic, cellular component, and pathway analyses were performed on differentially expressed genes and investigated with immunofluorescent staining experiments. Results Analysis of the gene expression data sets identified 1,215 genes that were differentially expressed between RCSsham and LEsham samples. Additionally, 283 genes were differentially expressed between the RCShNPCs and RCSsham samples. Comparison of these two gene sets identified 68 genes with inverse expression (termed rescue genes), including Pdc, Rp1, and Cdc42ep5. Functional, biologic, and cellular component analyses indicate that the immune response is enhanced in RCSsham. Pathway analysis of the differential expression gene sets identified three affected pathways in RCShNPCs, which all play roles in phagocytosis signaling. Immunofluorescent

  7. Channelrhodopsin-2 gene transduced into retinal ganglion cells restores functional vision in genetically blind rats.

    PubMed

    Tomita, Hiroshi; Sugano, Eriko; Isago, Hitomi; Hiroi, Teru; Wang, Zhuo; Ohta, Emi; Tamai, Makoto

    2010-03-01

    To test the hypothesis that transduction of the channelrhodopsin-2 (ChR2) gene, a microbial-type rhodopsin gene, into retinal ganglion cells of genetically blind rats will restore functional vision, we recorded visually evoked potentials and tested the experimental rats for the presence of optomotor responses. The N-terminal fragment of the ChR2 gene was fused to the fluorescent protein Venus and inserted into an adeno-associated virus to make AAV2-ChR2V. AAV2-ChR2V was injected intravitreally into the eyes of 6-month-old dystrophic RCS (rdy/rdy) rats. Visual function was evaluated six weeks after the injection by recording visually evoked potentials (VEPs) and testing optomotor responses. The expression of ChR2V in the retina was investigated histologically. We found that VEPs could not be recorded from 6-month-old dystrophic RCS rats that had not been injected with AAV2-ChR2V. In contrast, VEPs were elicited from RCS rats six weeks after injection with AAV2-ChR2V. The VEPs were recorded at stimulation rates <20Hz, which was the same as that of normal rats. Optomotor responses were also significantly better after the AAV2-ChR2V injection. Expression of ChR2V was observed mainly in the retinal ganglion cells. These findings demonstrate that visual function can be restored in blind rats by transducing the ChR2V gene into retinal ganglion cells.

  8. Mutation of CERKL, a Novel Human Ceramide Kinase Gene, Causes Autosomal Recessive Retinitis Pigmentosa (RP26)

    PubMed Central

    Tuson, Miquel; Marfany, Gemma; Gonzàlez-Duarte, Roser

    2004-01-01

    Retinitis pigmentosa (RP), the main cause of adult blindness, is a genetically heterogeneous disorder characterized by progressive loss of photoreceptors through apoptosis. Up to now, 39 genes and loci have been implicated in nonsyndromic RP, yet the genetic bases of >50% of the cases, particularly of the recessive forms, remain unknown. Previous linkage analysis in a Spanish consanguineous family allowed us to define a novel autosomal recessive RP (arRP) locus, RP26, within an 11-cM interval (17.4 Mb) on 2q31.2-q32.3. In the present study, we further refine the RP26 locus down to 2.5 Mb, by microsatellite and single-nucleotide polymorphism (SNP) homozygosity mapping. After unsuccessful mutational analysis of the nine genes initially reported in this region, a detailed gene search based on expressed-sequence-tag data was undertaken. We finally identified a novel gene encoding a ceramide kinase (CERKL), which encompassed 13 exons. All of the patients from the RP26 family bear a homozygous mutation in exon 5, which generates a premature termination codon. The same mutation was also characterized in another, unrelated, Spanish pedigree with arRP. Human CERKL is expressed in the retina, among other adult and fetal tissues. A more detailed analysis by in situ hybridization on adult murine retina sections shows expression of Cerkl in the ganglion cell layer. Ceramide kinases convert the sphingolipid metabolite ceramide into ceramide-1-phosphate, both key mediators of cellular apoptosis and survival. Ceramide metabolism plays an essential role in the viability of neuronal cells, the membranes of which are particularly rich in sphingolipids. Therefore, CERKL deficiency could shift the relative levels of the signaling sphingolipid metabolites and increase sensitivity of photoreceptor and other retinal cells to apoptotic stimuli. This is the first genetic report suggesting a direct link between retinal neurodegeneration in RP and sphingolipid-mediated apoptosis. PMID

  9. Gene therapy prospects--intranasal delivery of therapeutic genes.

    PubMed

    Podolska, Karolina; Stachurska, Anna; Hajdukiewicz, Karolina; Małecki, Maciej

    2012-01-01

    Gene therapy is recognized to be a novel method for the treatment of various disorders. Gene therapy strategies involve gene manipulation on broad biological processes responsible for the spreading of diseases. Cancer, monogenic diseases, vascular and infectious diseases are the main targets of gene therapy. In order to obtain valuable experimental and clinical results, sufficient gene transfer methods are required. Therapeutic genes can be administered into target tissues via gene carriers commonly defined as vectors. The retroviral, adenoviral and adeno-associated virus based vectors are most frequently used in the clinic. So far, gene preparations may be administered directly into target organs or by intravenous, intramuscular, intratumor or intranasal injections. It is common knowledge that the number of gene therapy clinical trials has rapidly increased. However, some limitations such as transfection efficiency and stable and long-term gene expression are still not resolved. Consequently, great effort is focused on the evaluation of new strategies of gene delivery. There are many expectations associated with intranasal delivery of gene preparations for the treatment of diseases. Intranasal delivery of therapeutic genes is regarded as one of the most promising forms of pulmonary gene therapy research. Gene therapy based on inhalation of gene preparations offers an alternative way for the treatment of patients suffering from such lung diseases as cystic fibrosis, alpha-1-antitrypsin defect, or cancer. Experimental and first clinical trials based on plasmid vectors or recombinant viruses have revealed that gene preparations can effectively deliver therapeutic or marker genes to the cells of the respiratory tract. The noninvasive intranasal delivery of gene preparations or conventional drugs seems to be very encouraging, although basic scientific research still has to continue.

  10. Gene therapy for high-grade glioma

    PubMed Central

    Natsume, Atsushi

    2008-01-01

    The treatment of high-grade gliomas remains difficult despite recent advances in surgery, radiotherapy and chemotherapy. True advances may emerge from the increasing understanding in molecular biology and discovery of novel mechanisms for the delivery of tumoricidal agents. In an attempt to overcome this formidable neoplasm, molecular approaches using gene therapy have been investigated clinically since 1992. The clinical trials have mainly been classified into three approaches: suicide gene therapy, immune gene therapy and oncolytic viral therapy. In this article, we review these approaches, which have been studied in previous and ongoing clinical trials. PMID:19262115

  11. The RPGRIP1-deficient dog, a promising canine model for gene therapy

    PubMed Central

    Lhériteau, Elsa; Libeau, Lyse; Stieger, Knut; Deschamps, Jack-Yves; Mendes-Madeira, Alexandra; Provost, Nathalie; Lemoine, Francoise; Mellersh, Cathryn; Ellinwood, N. Matthew; Cherel, Yan; Moullier, Philippe

    2009-01-01

    Purpose To evaluate the RPGRIP1-deficient miniature longhaired dachshund (MLHD) dog as a potential candidate for gene therapy. Methods Six RPGRIP1-deficient MLHD dogs from our dog colony have been observed for two years using a variety of noninvasive procedures. These included bilateral full-field electroretinograms (ERG) to evaluate retinal function, fundus photographs to evaluate retinal vascularization, and optical coherence tomographs (OCT) to evaluate retinal thickness. We also performed histological examination of hematoxylin- and eosin-stained retinal sections as well as sections labeled in situ by the terminal dUTP nick end labeling (TUNEL) method. Results ERG findings showed that as early as 2 months of age, cone function was lost while rod function was preserved. However, by 9 months of age, both cone and rod functions could not be detected. Functional visual assessment based on the ability to avoid obstacles showed that vision was retained up to the age of 11 months. Both OCT and histopathology studies revealed a progressive thinning of the outer nuclear layer (ONL) over the first 2 years of age. TUNEL labeling identified apoptotic photoreceptor cell death as the cause of this thinning of the ONL. Conclusions A treatment strategy should consist in initiating gene therapy as early as possible after birth to prevent or delay the loss of rod function. In the MLHD, successful subretinal delivery of a therapeutic vector is feasible at 2 months of age and may prevent or delay the loss of rod function. PMID:19223988

  12. Dog Models for Blinding Inherited Retinal Dystrophies

    PubMed Central

    Komáromy, András M.

    2015-01-01

    Abstract Spontaneous canine models exist for several inherited retinal dystrophies. This review will summarize the models and indicate where they have been used in translational gene therapy trials. The RPE65 gene therapy trials to treat childhood blindness are a good example of how studies in dogs have contributed to therapy development. Outcomes in human clinical trials are compared and contrasted with the result of the preclinical dog trials. PMID:25671556

  13. Dog models for blinding inherited retinal dystrophies.

    PubMed

    Petersen-Jones, Simon M; Komáromy, András M

    2015-03-01

    Spontaneous canine models exist for several inherited retinal dystrophies. This review will summarize the models and indicate where they have been used in translational gene therapy trials. The RPE65 gene therapy trials to treat childhood blindness are a good example of how studies in dogs have contributed to therapy development. Outcomes in human clinical trials are compared and contrasted with the result of the preclinical dog trials.

  14. Ipsilateral and Contralateral Retinal Ganglion Cells Express Distinct Genes during Decussation at the Optic Chiasm

    PubMed Central

    Marcucci, Florencia; Cerullo, Isadora

    2016-01-01

    The increasing availability of transcriptomic technologies within the last decade has facilitated high-throughput identification of gene expression differences that define distinct cell types as well as the molecular pathways that drive their specification. The retinal projection neurons, retinal ganglion cells (RGCs), can be categorized into distinct morphological and functional subtypes and by the laterality of their projections. Here, we present a method for purifying the sparse population of ipsilaterally projecting RGCs in mouse retina from their contralaterally projecting counterparts during embryonic development through rapid retrograde labeling followed by fluorescence-activated cell sorting. Through microarray analysis, we uncovered the distinct molecular signatures that define and distinguish ipsilateral and contralateral RGCs during the critical period of axonal outgrowth and decussation, with more than 300 genes differentially expressed within these two cell populations. Among the differentially expressed genes confirmed through in vivo expression validation, several genes that mark “immaturity” are expressed within postmitotic ipsilateral RGCs. Moreover, at least one complementary pair, Igf1 and Igfbp5, is upregulated in contralateral or ipsilateral RGCs, respectively, and may represent signaling pathways that determine ipsilateral versus contralateral RGC identity. Importantly, the cell cycle regulator cyclin D2 is highly expressed in peripheral ventral retina with a dynamic expression pattern that peaks during the period of ipsilateral RGC production. Thus, the molecular signatures of ipsilateral and contralateral RGCs and the mechanisms that regulate their differentiation are more diverse than previously expected. PMID:27957530

  15. Molecular analysis of the ABCA4 gene in Turkish patients with Stargardt disease and retinitis pigmentosa.

    PubMed

    Ozgül, Riza Köksal; Durukan, Hakan; Turan, Ayse; Oner, Cihan; Ogüs, Ay; Farber, Debora B

    2004-05-01

    The clinical importance of sequence variations in the ABCA4 gene has been extensively discussed during the last decade. Mutations in the ABCA4 gene are involved in several forms of inherited retinal degenerations. We screened all 50 exons of the ABCA4 gene in a cohort of 5 Stargardt Disease (STGD) and 35 autosomal recessive retinitis pigmentosa (arRP) patients of Turkish descent to assess the nature of ABCA4 mutant alleles in this population. Our results revealed the presence of three novel mutations: c.160T>G (p.C54G), c.2486C>T (p.T829M), and c.973-6C>A; two mutations previously reported, c.634C>T (p.R212C) and c.4253+4C>T, and several polymorphic changes in the ABCA4 gene among Turkish patients affected with Stargardt and arRP. To our knowledge this report represents the first published study of ABCA4 mutations in the Turkish population resulting in STGD. Copyright 2004 Wiley-Liss, Inc.

  16. Engineering Factor Viii for Hemophilia Gene Therapy

    PubMed Central

    Roberts, Sean A.; Dong, Biao; Firrman, Jenni A.; Moore, Andrea R.; Sang, Nianli; Xiao, Weidong

    2012-01-01

    Current treatment of hemophilia A by intravenous infusion of factor VIII (fVIII) concentrates is very costly and has a potential adverse effect of developing inhibitors. Gene therapy, on the other hand, can potentially overcome these limitations associated with fVIII replacement therapy. Although hemophilia B gene therapy has achieved promising outcomes in human clinical trials, hemophilia A gene therapy lags far behind. Compared to factor IX, fVIII is a large protein which is difficult to express at sustaining therapeutic levels when delivered by either viral or non-viral vectors. To improve fVIII gene delivery, numerous strategies have been exploited to engineer the fVIII molecule and overcome the hurdles preventing long term and high level expression. Here we reviewed these strategies, and discussed their pros and cons in human gene therapy of hemophilia A. PMID:23565342

  17. Gene therapy for ocular diseases meditated by ultrasound and microbubbles (Review).

    PubMed

    Wan, Caifeng; Li, Fenghua; Li, Hongli

    2015-10-01

    The eye is an ideal target organ for gene therapy as it is easily accessible and immune‑privileged. With the increasing insight into the underlying molecular mechanisms of ocular diseases, gene therapy has been proposed as an effective approach. Successful gene therapy depends on efficient gene transfer to targeted cells to prove stable and prolonged gene expression with minimal toxicity. At present, the main hindrance regarding the clinical application of gene therapy is not the lack of an ideal gene, but rather the lack of a safe and efficient method to selectively deliver genes to target cells and tissues. Ultrasound‑targeted microbubble destruction (UTMD), with the advantages of high safety, repetitive applicability and tissue targeting, has become a potential strategy for gene‑ and drug delivery. When gene‑loaded microbubbles are injected, UTMD is able to enhance the transport of the gene to the targeted cells. High‑amplitude oscillations of microbubbles act as cavitation nuclei which can effectively focus ultrasound energy, produce oscillations and disruptions that increase the permeability of the cell membrane and create transient pores in the cell membrane. Thereby, the efficiency of gene therapy can be significantly improved. The UTMD‑mediated gene delivery system has been widely used in pre‑clinical studies to enhance gene expression in a site‑specific manner in a variety of organs. With reasonable application, the effects of sonoporation can be spatially and temporally controlled to improve localized tissue deposition of gene complexes for ocular gene therapy applications. In addition, appropriately powered, focused ultrasound combined with microbubbles can induce a reversible disruption of the blood‑retinal barrier with no significant side effects. The present review discusses the current status of gene therapy of ocular diseases as well as studies on gene therapy of ocular diseases meditated by UTMD.

  18. Cancer gene therapy targeting cellular apoptosis machinery.

    PubMed

    Jia, Lin-Tao; Chen, Si-Yi; Yang, An-Gang

    2012-11-01

    The unraveling of cellular apoptosis machinery provides novel targets for cancer treatment, and gene therapy targeting this suicidal system has been corroborated to cause inflammation-free autonomous elimination of neoplastic cells. The apoptotic machinery can be targeted by introduction of a gene encoding an inducer, mediator or executioner of apoptotic cell death or by inhibition of anti-apoptotic gene expression. Strategies targeting cancer cells, which are achieved by selective gene delivery, specific gene expression or secretion of target proteins via genetic modification of autologous cells, dictate the outcome of apoptosis-based cancer gene therapy. Despite so far limited clinical success, gene therapy targeting the apoptotic machinery has great potential to benefit patients with threatening malignancies provided the availability of efficient and specific gene delivery and administration systems.

  19. Gene Therapy for Leber's Congenital Amaurosis is Safe and Effective Through 1.5 Years After Vector Administration

    PubMed Central

    Simonelli, Francesca; Maguire, Albert M; Testa, Francesco; Pierce, Eric A; Mingozzi, Federico; Bennicelli, Jeannette L; Rossi, Settimio; Marshall, Kathleen; Banfi, Sandro; Surace, Enrico M; Sun, Junwei; Redmond, T Michael; Zhu, Xiaosong; Shindler, Kenneth S; Ying, Gui-Shuang; Ziviello, Carmela; Acerra, Carmela; Wright, J Fraser; McDonnell, Jennifer Wellman; High, Katherine A; Bennett, Jean; Auricchio, Alberto

    2009-01-01

    The safety and efficacy of gene therapy for inherited retinal diseases is being tested in humans affected with Leber's congenital amaurosis (LCA), an autosomal recessive blinding disease. Three independent studies have provided evidence that the subretinal administration of adeno-associated viral (AAV) vectors encoding RPE65 in patients affected with LCA2 due to mutations in the RPE65 gene, is safe and, in some cases, results in efficacy. We evaluated the long-term safety and efficacy (global effects on retinal/visual function) resulting from subretinal administration of AAV2-hRPE65v2. Both the safety and the efficacy noted at early timepoints persist through at least 1.5 years after injection in the three LCA2 patients enrolled in the low dose cohort of our trial. A transient rise in neutralizing antibodies to AAV capsid was observed but there was no humoral response to RPE65 protein. The persistence of functional amelioration suggests that AAV-mediated gene transfer to the human retina does not elicit immunological responses which cause significant loss of transduced cells. The persistence of physiologic effect supports the possibility that gene therapy may influence LCA2 disease progression. The safety of the intervention and the stability of the improvement in visual and retinal function in these subjects support the use of AAV-mediated gene augmentation therapy for treatment of inherited retinal diseases. PMID:19953081

  20. Gene therapy for Leber's congenital amaurosis is safe and effective through 1.5 years after vector administration.

    PubMed

    Simonelli, Francesca; Maguire, Albert M; Testa, Francesco; Pierce, Eric A; Mingozzi, Federico; Bennicelli, Jeannette L; Rossi, Settimio; Marshall, Kathleen; Banfi, Sandro; Surace, Enrico M; Sun, Junwei; Redmond, T Michael; Zhu, Xiaosong; Shindler, Kenneth S; Ying, Gui-Shuang; Ziviello, Carmela; Acerra, Carmela; Wright, J Fraser; McDonnell, Jennifer Wellman; High, Katherine A; Bennett, Jean; Auricchio, Alberto

    2010-03-01

    The safety and efficacy of gene therapy for inherited retinal diseases is being tested in humans affected with Leber's congenital amaurosis (LCA), an autosomal recessive blinding disease. Three independent studies have provided evidence that the subretinal administration of adeno-associated viral (AAV) vectors encoding RPE65 in patients affected with LCA2 due to mutations in the RPE65 gene, is safe and, in some cases, results in efficacy. We evaluated the long-term safety and efficacy (global effects on retinal/visual function) resulting from subretinal administration of AAV2-hRPE65v2. Both the safety and the efficacy noted at early timepoints persist through at least 1.5 years after injection in the three LCA2 patients enrolled in the low dose cohort of our trial. A transient rise in neutralizing antibodies to AAV capsid was observed but there was no humoral response to RPE65 protein. The persistence of functional amelioration suggests that AAV-mediated gene transfer to the human retina does not elicit immunological responses which cause significant loss of transduced cells. The persistence of physiologic effect supports the possibility that gene therapy may influence LCA2 disease progression. The safety of the intervention and the stability of the improvement in visual and retinal function in these subjects support the use of AAV-mediated gene augmentation therapy for treatment of inherited retinal diseases.

  1. Gene therapy for childhood immunological diseases.

    PubMed

    Kohn, D B

    2008-01-01

    Gene therapy using autologous hematopoietic stem cells (HSC) that are corrected with the normal gene may have a beneficial effect on blood cell production or function, without the immunologic complications of allogeneic HSC transplantation. Childhood immunological diseases are highly favorable candidates for responses to gene therapy using HSC. Hemoglobinopathies, lysosomal and metabolic disorders and defects of hematopoietic stem and progenitor cells should also be ameliorated by gene therapy using autologous HSC. At present, gene therapy has been beneficial for patients with XSCID, ADA-deficient SCID and chronic granulomatous disease. The principle that partial marrow conditioning increases engraftment of gene-corrected HSC has been demonstrated. Clinical trials are being developed in Europe and the United States to treat several other genetic blood cell disorders. This progress is tempered by the serious complication observed in XSCID patients developing T lymphoproliferative disease. New methods for gene transfer (lentiviral and foamy viral vectors, semi-viral systems and gene correction) may retain or further increase the efficacy and decrease the risks from gene therapy using HSC. Ultimately, the relative benefits and risks of autologous gene therapy will be weighed against other available options (for example, allogeneic HSCT) to determine the treatment of choice.

  2. Nuclear receptor NR2E3 gene mutations distort human retinal laminar architecture and cause an unusual degeneration.

    PubMed

    Jacobson, Samuel G; Sumaroka, Alexander; Aleman, Tomas S; Cideciyan, Artur V; Schwartz, Sharon B; Roman, Alejandro J; McInnes, Roderick R; Sheffield, Val C; Stone, Edwin M; Swaroop, Anand; Wright, Alan F

    2004-09-01

    Mutations in the nuclear receptor gene, NR2E3, cause a disorder of human retinal photoreceptor development characterized by hyperfunction and excess of the minority S (short wavelength or blue) cone photoreceptor type, but near absence of function of the majority rod receptor. NR2E3 disease can also progress to blindness. How the human retina accommodates mis-specified types and numbers of neurons and advances to retinal degeneration are unknown. We studied the retinal organization in vivo of patients with NR2E3 mutations. Early human NR2E3 disease with S cone hyperfunction showed thickened retinal layers within an otherwise normally structured retina. With visual loss, however, lamination was coarse and there was a strikingly thick and bulging appearance to the retina, localized to an annulus encircling the central fovea. This pattern was not found in other retinal degenerations. The abnormal laminar retinal architecture of early NR2E3 disease may be due in part to larger cells with an S cone phenotype in place of rods that failed to differentiate. The later-stage dysplastic appearance suggests a previously unrecognized proliferative response in human retinal degeneration.

  3. Dosage Thresholds for AAV2 and AAV8 Photoreceptor Gene Therapy in Monkey

    PubMed Central

    Vandenberghe, Luk H.; Bell, Peter; Maguire, Albert M.; Cearley, Cassia N.; Xiao, Ru; Calcedo, Roberto; Wang, Lili; Castle, Michael J.; Maguire, Alexandra C.; Grant, Rebecca; Wolfe, John H.; Wilson, James M.; Bennett, Jean

    2016-01-01

    Gene therapy is emerging as a therapeutic modality for treating disorders of the retina. Photoreceptor cells are the primary cell type affected in many inherited diseases of retinal degeneration. Successfully treating these diseases with gene therapy requires the identification of efficient and safe targeting vectors that can transduce photoreceptor cells. One serotype of adeno-associated virus, AAV2, has been used successfully in clinical trials to treat a form of congenital blindness that requires transduction of the supporting cells of the retina in the retinal pigment epithelium (RPE). Here, we determined the dose required to achieve targeting of AAV2 and AAV8 vectors to photoreceptors in nonhuman primates. Transgene expression in animals injected subretinally with various doses of AAV2 or AAV8 vectors carrying a green fluorescent protein transgene was correlated with surgical, clinical, and immunological observations. Both AAV2 and AAV8 demonstrated efficient transduction of RPE, but AAV8 was markedly better at targeting photoreceptor cells. These preclinical results provide guidance for optimal vector and dose selection in future human gene therapy trials to treat retinal diseases caused by loss of photoreceptors. PMID:21697530

  4. Candidate diseases for prenatal gene therapy.

    PubMed

    David, Anna L; Waddington, Simon N

    2012-01-01

    Prenatal gene therapy aims to deliver genes to cells and tissues early in prenatal life, allowing correction of a genetic defect, before irreparable tissue damage has occurred. In contrast to postnatal gene therapy, prenatal application may target genes to a large population of stem cells, and the smaller fetal size allows a higher vector to target cell ratio to be achieved. Early gestation delivery may allow the development of immune tolerance to the transgenic protein, which would facilitate postnatal repeat vector administration if needed. Moreover, early delivery would avoid anti-vector immune responses which are often acquired in postnatal life. The NIH Recombinant DNA Advisory Committee considered that a candidate disease for prenatal gene therapy should pose serious morbidity and mortality risks to the fetus or neonate, and not have any effective postnatal treatment. Prenatal gene therapy would therefore be appropriate for life-threatening disorders, in which prenatal gene delivery maintains a clear advantage over cell transplantation or postnatal gene therapy. If deemed safer and more efficacious, prenatal gene therapy may be applicable for nonlethal conditions if adult gene transfer is unlikely to be of benefit. Many candidate diseases will be inherited congenital disorders such as thalassaemia or lysosomal storage disorders. However, obstetric conditions such as fetal growth restriction may also be treated using a targeted gene therapy approach. In each disease, the condition must be diagnosed prenatally, either via antenatal screening and prenatal diagnosis, for example, in the case of hemophilias, or by ultrasound assessment of the fetus, for example, congenital diaphragmatic hernia. In this chapter, we describe some examples of the candidate diseases and discuss how a prenatal gene therapy approach might work.

  5. Targeted Gene Therapy for Breast Cancer

    DTIC Science & Technology

    2005-06-01

    or transduced son, WI). A mouse monoclonal anti-human VEGF with 100 multiplicities of infection (MOI) of rAAV-sFlt-l. receptor-1 (FIt-1 receptor...only partial amounts of the cancer patients correlate with advanced and metastatic deficient protein/enzyme for phenotypic correction of disease and...activity of matrix metalloproteinase. Cancer Res 2000;60: 4- sulfatase to the retinal pigment epithelium of feline mucopolysacchar- 5410-3. idosis VI. J Gene Med 2002;4:613-321.

  6. High-Throughput Retina-Array for Screening 93 Genes Involved in Inherited Retinal Dystrophy

    PubMed Central

    Song, Jin; Smaoui, Nizar; Ayyagari, Radha; Stiles, David; Benhamed, Sonia; MacDonald, Ian M.; Daiger, Stephen P.; Tumminia, Santa J.; Hejtmancik, Fielding

    2011-01-01

    Purpose. Retinal dystrophy (RD) is a broad group of hereditary disorders with heterogeneous genotypes and phenotypes. Current available genetic testing for these diseases is complicated, time consuming, and expensive. This study was conducted to develop and apply a microarray-based, high-throughput resequencing system to detect sequence alterations in genes related to inherited RD. Methods. A customized 300-kb resequencing chip, Retina-Array, was developed to detect sequence alterations of 267,550 bases of both sense and antisense sequence in 1470 exons spanning 93 genes involved in inherited RD. Retina-Array was evaluated in 19 patient samples with inherited RD provided by the eyeGENE repository and four Centre d'Etudes du Polymorphisme Humaine reference samples through a high-throughput experimental approach that included an automated PCR assay setup and quantification, efficient post-quantification data processing, optimized pooling and fragmentation, and standardized chip processing. Results. The performance of the chips demonstrated that the average base pair call rate and accuracy were 93.56% and 99.86%, respectively. In total, 304 candidate variations were identified using a series of customized screening filters. Among 174 selected variations, 123 (70.7%) were further confirmed by dideoxy sequencing. Analysis of patient samples using Retina-Array resulted in the identification of 10 known mutations and 12 novel variations with high probability of deleterious effects. Conclusions. This study suggests that Retina-Array might be a valuable tool for the detection of disease-causing mutations and disease severity modifiers in a single experiment. Retinal-Array may provide a powerful and feasible approach through which to study genetic heterogeneity in retinal diseases. PMID:22025579

  7. Recent advances in fetal gene therapy.

    PubMed

    Buckley, Suzanne M K; Rahim, Ahad A; Chan, Jerry K Y; David, Anna L; Peebles, Donald M; Coutelle, Charles; Waddingtont, Simon N

    2011-04-01

    Over the first decade of this new millennium gene therapy has demonstrated clear clinical benefits in several diseases for which conventional medicine offers no treatment. Clinical trials of gene therapy for single gene disorders have recruited predominantly young patients since older subjects may have suffered irrevocablepathological changes or may not be available because the disease is lethal relatively early in life. The concept of fetal gene therapy is an extension of this principle in that diseases in which irreversible changes occur at or beforebirth can be prevented by gene supplementation or repair in the fetus or associated maternal tissues. This article ccnsiders the enthusiasm and skepticism held for fetal gene therapy and its potential for clinical application. It coversa spectrum of candidate diseases for fetal gene therapy including Pompe disease, Gaucher disease, thalassemia, congenital protein C deficiency and cystic fibrosis. It outlines successful and not-so-successful examples of fetal gene therapy in animal models. Finally the application and potential of fetal gene transfer as a fundamental research tool for developmental biology and generation of somatic transgenic animals is surveyed.

  8. Gene therapy for sickle cell disease.

    PubMed

    Olowoyeye, Abiola; Okwundu, Charles I

    2016-11-14

    Sickle cell disease encompasses a group of genetic disorders characterized by the presence of at least one hemoglobin S (Hb S) allele, and a second abnormal allele that could allow abnormal hemoglobin polymerisation leading to a symptomatic disorder.Autosomal recessive disorders (such as sickle cell disease) are good candidates for gene therapy because a normal phenotype can be restored in diseased cells with only a single normal copy of the mutant gene. This is an update of a previously published Cochrane Review. The objectives of this review are:to determine whether gene therapy can improve survival and prevent symptoms and complications associated with sickle cell disease;to examine the risks of gene therapy against the potential long-term gain for people with sickle cell disease. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register, which comprises of references identified from comprehensive electronic database searches and searching relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 15 August 2016. All randomised or quasi-randomised clinical trials (including any relevant phase 1, 2 or 3 trials) of gene therapy for all individuals with sickle cell disease, regardless of age or setting. No trials of gene therapy for sickle cell disease were found. No trials of gene therapy for sickle cell disease were reported. No randomised or quasi-randomised clinical trials of gene therapy for sickle cell disease were reported. Thus, no objective conclusions or recommendations in practice can be made on gene therapy for sickle cell disease. This systematic review has identified the need for well-designed, randomised controlled trials to assess the benefits and risks of gene therapy for sickle cell disease.

  9. Achromatopsia as a potential candidate for gene therapy.

    PubMed

    Pang, Ji-Jing; Alexander, John; Lei, Bo; Deng, Wentao; Zhang, Keqing; Li, Qiuhong; Chang, Bo; Hauswirth, William W

    2010-01-01

    Achromatopsia is an autosomal recessive retinal disease involving loss of cone function that afflicts approximately 1 in 30,000 individuals. Patients with achromatopsia usually have visual acuities lower than 20/200 because of the central vision loss, photophobia, complete color blindness and reduced cone-mediated electroretinographic (ERG) amplitudes. Mutations in three genes have been found to be the primary causes of achromatopsia, including CNGB3 (beta subunit of the cone cyclic nucleotide-gated cation channel), CNGA3 (alpha subunit of the cone cyclic nucleotide-gated cation channel), and GNAT2 (cone specific alpha subunit of transducin). Naturally occurring mouse models with mutations in Cnga3 (cpfl5 mice) and Gnat2 (cpfl3 mice) were discovered at The Jackson Laboratory. A natural occurring canine model with CNGB3 mutations has also been found. These animal models have many of the central phenotypic features of the corresponding human diseases. Using adeno-associated virus (AAV)-mediated gene therapy, we and others show that cone function can be restored in all three models. These data suggest that human achromatopsia may be a good candidate for corrective gene therapy.

  10. Achromatopsia as a Potential Candidate for Gene Therapy

    PubMed Central

    Pang, Ji-jing; Alexander, John; Lei, Bo; Deng, Wentao; Zhang, Keqing; Li, Qiuhong; Chang, Bo; Hauswirth, William W.

    2013-01-01

    Achromatopsia is an autosomal recessive retinal disease involving loss of cone function that afflicts approximately 1 in 30,000 individuals. Patients with achromatopsia usually have visual acuities lower than 20/200 because of the central vision loss, photophobia, complete color blindness and reduced cone-mediated electroretinographic (ERG) amplitudes. Mutations in three genes have been found to be the primary causes of achromatopsia, including CNGB3 (beta subunit of the cone cyclic nucleotide-gated cation channel), CNGA3 (alpha subunit of the cone cyclic nucleotide-gated cation channel), and GNAT2 (cone specific alpha subunit of transducin). Naturally occurring mouse models with mutations in Cnga3 (cpfl5 mice) and Gnat2 (cpfl3 mice) were discovered at The Jackson Laboratory. A natural occurring canine model with CNGB3 mutations has also been found. These animal models have many of the central phenotypic features of the corresponding human diseases. Using adeno-associated virus (AAV)-mediated gene therapy, we and others show that cone function can be restored in all three models. These data suggest that human achromatopsia may be a good candidate for corrective gene therapy. PMID:20238068

  11. Molecular study of the rhodopsin gene in retinitis pigmentosa patients in the Basque Country.

    PubMed Central

    Alvarez, A I; Arostegui, E; Martin, R; Duran, M; Onaindia, M L; Molina, M; Tejada, M I

    1998-01-01

    Retinitis pigmentosa (RP) is a degenerative disorder affecting the outer segment of the retina and leading to night blindness and progressive visual field loss. The rhodopsin gene encodes a photolabile pigment located in the rod outer segments constituting around 80-90% of its protein content and is the initiation point for the visual cascade upon absorption of a single photon. Seventy-five unrelated, isolated RP families in the Basque Country, with at least one affected member, were diagnosed at our hospital after ophthalmic examination and electroretinogram analysis. The patients received genetic counselling according to their individual case based on their clinical diagnosis. The modes of inheritance found from pedigree studies were the following: 20% (15/75) were classified as autosomal dominant retinitis pigmentosa (ADRP), 17.33% (13/75) were autosomal recessive (ARRP), 2.66% (2/75) were unclassified (NC), and 60% (45/75) were sporadic cases (SCRP). From these families, 75 unrelated and affected index cases together with 22 affected relatives and 42 unaffected relatives were screened for mutations in the rhodopsin gene by GC clamped denaturing gradient gel electrophoresis. Our results showed that five ADRP, three ARRP, 15 SCRP, and one NC families had alterations in this gene. Only three of these alterations, that is 4% (3/75) (95% CL 0-8), appeared to be responsible for the disease. This represents a lower percentage than the 10% previously reported. PMID:9610801

  12. Molecular study of the rhodopsin gene in retinitis pigmentosa patients in the Basque Country.

    PubMed

    Alvarez, A I; Arostegui, E; Martin, R; Duran, M; Onaindia, M L; Molina, M; Tejada, M I

    1998-05-01

    Retinitis pigmentosa (RP) is a degenerative disorder affecting the outer segment of the retina and leading to night blindness and progressive visual field loss. The rhodopsin gene encodes a photolabile pigment located in the rod outer segments constituting around 80-90% of its protein content and is the initiation point for the visual cascade upon absorption of a single photon. Seventy-five unrelated, isolated RP families in the Basque Country, with at least one affected member, were diagnosed at our hospital after ophthalmic examination and electroretinogram analysis. The patients received genetic counselling according to their individual case based on their clinical diagnosis. The modes of inheritance found from pedigree studies were the following: 20% (15/75) were classified as autosomal dominant retinitis pigmentosa (ADRP), 17.33% (13/75) were autosomal recessive (ARRP), 2.66% (2/75) were unclassified (NC), and 60% (45/75) were sporadic cases (SCRP). From these families, 75 unrelated and affected index cases together with 22 affected relatives and 42 unaffected relatives were screened for mutations in the rhodopsin gene by GC clamped denaturing gradient gel electrophoresis. Our results showed that five ADRP, three ARRP, 15 SCRP, and one NC families had alterations in this gene. Only three of these alterations, that is 4% (3/75) (95% CL 0-8), appeared to be responsible for the disease. This represents a lower percentage than the 10% previously reported.

  13. Altered glial gene expression, density, and architecture in the visual cortex upon retinal degeneration.

    PubMed

    Cornett, Ashley; Sucic, Joseph F; Hillsburg, Dylan; Cyr, Lindsay; Johnson, Catherine; Polanco, Anthony; Figuereo, Joe; Cabine, Kenneth; Russo, Nickole; Sturtevant, Ann; Jarvinen, Michael K

    2011-11-08

    Genes encoding the proteins of cytoskeletal intermediate filaments (IF) are tightly regulated, and they are important for establishing neural connections. However, it remains uncertain to what extent neurological disease alters IF gene expression or impacts cells that express IFs. In this study, we determined the onset of visual deficits in a mouse model of progressive retinal degeneration (Pde6b(-) mice; Pde6b(+) mice have normal vision) by observing murine responses to a visual task throughout development, from postnatal day (PND) 21 to adult (N=174 reliable observations). Using Q-PCR, we evaluated whether expression of the genes encoding two Type III IF proteins, glial fibrillary acidic protein (GFAP) and vimentin was altered in the visual cortex before, during, and after the onset of visual deficits. Using immunohistochemical techniques, we investigated the impact of vision loss on the density and morphology of astrocytes that expressed GFAP and vimentin in the visual cortex. We found that Pde6b(-) mice displayed 1) evidence of blindness at PND 49, with visual deficits detected at PND 35, 2) reduced GFAP mRNA expression in the visual cortex between PND 28 and PND 49, and 3) an increased ratio of vimentin:GFAP-labeled astrocytes at PND 49 with reduced GFAP cell body area. Together, these findings demonstrate that retinal degeneration modifies cellular and molecular indices of glial plasticity in a visual system with drastically reduced visual input. The functional consequences of these structural changes remain uncertain.

  14. [Gene therapy of neurological diseases].

    PubMed

    Kahn, A; Haase, G; Akli, S; Guidotti, J E

    1996-01-01

    transgenes transferred through adenoviral vectors, we have constructed vectors with cDNAs or genes for various neutrophic factors: CNTF, NT3, BDNF and GDNF. These vectors were biologically active on target cells, ex vivo and in vivo. In the pmn mouse model of progressive motor neuronal degeneration, some of these vectors, alone or combined, allowed for prolongation of life of homozygous animals by more than two fold, and for decrease in the demyelination of phrenic nerve axons. Finally, we have also constructed an adenoviral vector carrying the alpha-hexosaminidase cDNA, encoding the enzyme subunit deficient in Tay Sachs patients. This vector permitted to normalize ganglioside metabolism in Tay Sachs fibroblasts and is currently tested in knock out mice deficient in hexosaminidase A. In spite of all these encouraging results, we are nevertheless aware that progress in vector design and delivery strategies will be needed before gene therapy can become a realistic therapeutical strategy in humans.

  15. Differential proteomics and functional research following gene therapy in a mouse model of Leber congenital amaurosis.

    PubMed

    Zheng, Qinxiang; Ren, Yueping; Tzekov, Radouil; Zhang, Yuanping; Chen, Bo; Hou, Jiangping; Zhao, Chunhui; Zhu, Jiali; Zhang, Ying; Dai, Xufeng; Ma, Shan; Li, Jia; Pang, Jijing; Qu, Jia; Li, Wensheng

    2012-01-01

    Leber congenital amaurosis (LCA) is one of the most severe forms of inherited retinal degeneration and can be caused by mutations in at least 15 different genes. To clarify the proteomic differences in LCA eyes, a cohort of retinal degeneration 12 (rd12) mice, an LCA2 model caused by a mutation in the RPE65 gene, were injected subretinally with an AAV vector (scAAV5-smCBA-hRPE65) in one eye, while the contralateral eye served as a control. Proteomics were compared between untreated rd12 and normal control retinas on P14 and P21, and among treated and untreated rd12 retinas and control retinas on P42. Gene therapy in rd12 mice restored retinal function in treated eyes, which was demonstrated by electroretinography (ERG). Proteomic analysis successfully identified 39 proteins expressed differently among the 3 groups. The expression of 3 proteins involved in regulation of apoptosis and neuroptotection (alpha A crystallin, heat shock protein 70 and peroxiredoxin 6) were investigated further. Immunofluorescence, Western blot and real-time PCR confirmed the quantitative changes in their expression. Furthermore, cell culture studies suggested that peroxiredoxin 6 could act in an antioxidant role in rd12 mice. Our findings support the feasibility of gene therapy in LCA2 patients and support a role for alpha A crystallin, heat shock protein 70 and peroxiredoxin 6 in the pathogenetic mechanisms involved in LCA2 disease process.

  16. Gene therapy for B cell lymphomas.

    PubMed

    Fielding, A K; Russell, S J

    1997-01-01

    The use of genes or genetically modified cells for therapeutic benefit is likely to have a significant therapeutic role for patients with B cell lymphomas in the future. To date, most gene therapy strategies applicable to the therapy of these diseases have not reached the point of clinical study. Adoptive immunotherapy using donor leucocyte infusion to treat aggressive B cell neoplasms in immunosuppressed patients has, however, shown great promise clinically, and studies of idiotypic vaccination in patients with low grade B cell neoplasms are also under way. Results from in vitro and animal studies continue to suggest that it may become possible to use the immune system for therapeutic benefit, and many current basic research strategies in the gene therapy of B cell non-Hodgkin's lymphoma are based on immune modulation of T cells or tumour cells themselves. Other major approaches to gene therapy for B cell malignancies include the introduction of directly toxic or "suicide genes" into B cells or the chemoprotection of haemopoietic stem cells by the introduction of drug resistance genes. All of these approaches require efficient and accurate gene transfer as well as correct expression of the gene product within the target cell. Although some way from therapeutic use, specific targeting of gene delivery is an area of active investigation and will be of value in many of the gene therapy strategies applicable to B cell lymphomas.

  17. Vectors--shuttle vehicles for gene therapy.

    PubMed

    Wilson, J M

    1997-01-01

    Gene therapy is being considered for the treatment of various inherited and acquired disorders. The basic premise of this new therapeutic modality is manipulation of gene expression towards a therapeutic end. The early development of the field focused on a technique called ex vivo gene therapy in which autologous cells are genetically manipulated in culture prior to transplantation. Recent advances have stimulated the development of in vivo gene therapy approaches based on direct delivery of the therapeutic gene to cells in vivo. The rate-limiting technologies of gene therapy are the gene delivery vehicles, called vectors, used to accomplish gene transfer. The most efficient vectors are based on recombinant versions of viruses with retroviral vectors serving as prototypes. This viral vector system has been exploited in ex vivo approaches of gene therapy in which cultured, dividing cells are transduced with the recombinant virus resulting in integration of the proviral DNA into the chromosomal DNA of the recipient cell. The use of retroviral vectors in gene therapy has been restricted to ex vivo approaches because of difficulties in purifying the virion and the requirement that the target cell is dividing at the time of transduction. More recently, vectors based on adenoviruses have been developed for in vivo gene therapy. These viruses can be grown in large quantities and highly purified. Importantly, they efficiently transduce the recombinant genome into non-dividing cells. Applications include in vivo gene delivery to a variety of targets such as muscle, lung, liver and the central nervous system. Clinical trials of in vivo delivery with adenoviruses have been undertaken for the treatment of cystic fibrosis.

  18. Noncoding RNA for Cancer Gene Therapy.

    PubMed

    Zhong, Xiaomin; Zhang, Dongmei; Xiong, Minmin; Zhang, Lin

    Gene therapy is a prospective strategy to modulate gene expression level in specific cells to treat human inherited diseases, cancers, and acquired disorders. A subset of noncoding RNAs, microRNAs (miRNAs) and small interference RNAs (siRNAs), compose an important class of widely used effectors for gene therapy, especially in cancer treatment. Functioning through the RNA interference (RNAi) mechanism, miRNA and siRNA show potent ability in silencing oncogenic factors for cancer gene therapy. For a better understanding of this field, we reviewed the mechanism and biological function, the principles of design and synthesis, and the delivery strategies of noncoding RNAs with clinical potentials in cancer gene therapy.

  19. Retinoids for Treatment of Retinal Diseases

    PubMed Central

    Palczewski, Krzysztof

    2010-01-01

    Knowledge about retinal photoreceptor signal transduction and the visual cycle required for normal eyesight has expanded exponentially over the past decade. Substantial progress in human genetics has allowed identification of candidate genes and complex networks underlying inherited retinal diseases. Natural mutations in animal models that mimic human diseases have been characterized and advanced genetic manipulation now permits generation of small mammalian models of human retinal diseases. Pharmacological repair of defective visual processes in animal models not only validates their involvement in vision but also provides great promise for developing improved therapies for the millions that are progressing towards blindness or are almost completely robbed of eyesight. PMID:20435355

  20. Retinoids for treatment of retinal diseases.

    PubMed

    Palczewski, Krzysztof

    2010-06-01

    Knowledge about retinal photoreceptor signal transduction and the visual cycle required for normal eyesight has increased exponentially over the past decade. Substantial progress in human genetics has facilitated the identification of candidate genes and complex networks underlying inherited retinal diseases. Natural mutations in animal models that mimic human diseases have been characterized and advanced genetic manipulation can now be used to generate small mammalian models of human retinal diseases. Pharmacological repair of defective visual processes in animal models not only validates their involvement in vision, but also provides great promise for the development of improved therapies for millions who are progressing towards blindness or are almost completely robbed of their eyesight.

  1. A novel nonsense mutation in rhodopsin gene in two Indonesian families with autosomal recessive retinitis pigmentosa.

    PubMed

    Kartasasmita, Arief; Fujiki, Keiko; Iskandar, Erwin; Sovani, Iwan; Fujimaki, Takuro; Murakami, Akira

    2011-03-01

    To report a novel, identical nonsense mutation in the rhodopsin (RHO) gene in two Indonesian families with autosomal recessive retinitis pigmentosa (arRP). Mutation screening for the RHO gene was performed in 38 unrelated patients with retinitis pigmentosa (RP) by direct sequencing. Clinical features were also characterized, through complete ophthalmologic examination. Family members of RP patients testing positive for the RHO gene were subjected to genetic and clinical examination. To assess the founder effect in the two families, haplotype analysis also was performed. A novel homozygous nonsense mutation was detected in two patients by a G to A transition at nucleotide position 482 in exon 2 of the RHO gene, resulting in substitution of a tryptophan-to-stop at codon 161 (c.482G>A, p.W161X). Examination of family members of these 2 patients showed that the affected members were homozygous and unaffected carriers were heterozygous for the p.W161X mutation. Haplotype analysis revealed that members of the two families carried the same disease-associated variants in markers (IVS1 RHO and D3S2322). No p.W161X mutations were detected in 45 normal Indonesian subjects, nor were any mutations detected in exons 1-5 of the RHO gene in the remaining 36 RP patients. We detected a novel, recessive nonsense mutation (p.W161X) in the RHO gene of two families through mutation screening of RHO in 38 Indonesian RP patients. Haplotype analysis suggested that p.W161X was the founder mutation.

  2. Evaluation of the United States Public Health Service guidelines for discontinuation of anti-CMV therapy after immune recovery in patients with CMV retinitis

    PubMed Central

    Holbrook, Janet T.; Colvin, Ryan; Van Natta, Mark L.; Thorne, Jennifer E.; Bardsley, Mark; Jabs, Douglas A.

    2011-01-01

    Purpose To evaluate US Public Health Service (USPHS) guidelines for discontinuing anti-CMV therapy in patients with AIDS who have immune recovery and quiescent retinitis after initiating highly active anti-retroviral therapy (HAART). Design Cohort study of patients with CMV retinitis (Longitudinal Study of Ocular Complications of AIDS). Methods Participants had CMV retinitis and CD4+ T-cell counts of 50 cells/uL or fewer enrolled from 1998 to 2009 who demonstrated sustained immune recovery (two consecutive CD4+ T-cell counts of 100 cells/uL or more at least 6 months apart) and inactive retinitis. Participants were classified into 2 groups according to anti-CMV treatment after immune recover: (1) continued anti-CMV therapy and (2) discontinued therapy. We evaluated survival, visual acuity, and CMV retinitis activity; we employed propensity scores to adjust for confounding factors for these analyses. Results Of 152 participants reviewed, 71 demonstrated immune recovery; 37 of whom discontinued therapy and 34 who continued therapy. At immune recovery, participants continuing therapy tended to be older (44 vs 40 years, P=0.09), have bilateral retinitis (53% vs 32%, P=0.10), and have lower CD4+ T-cell counts (148 vs 207 cells/μL, P<0.001). There were no statistical differences in any of the clinical outcomes (death, retinitis progress, visual acuity or incidence of bilateral retinitis). Both groups lost visual acuity during follow-up, on average 1.2 letters per year (P<0.01). Conclusion Discontinuation of anti-CMV therapy after immune recovery did not increase the risk of poor outcomes. These results support the current guidelines for discontinuation of anti-CMV therapy after achievement of sustained immune recovery. PMID:21742304

  3. Evaluation of the United States public health service guidelines for discontinuation of anticytomegalovirus therapy after immune recovery in patients with cytomegalovirus retinitis.

    PubMed

    Holbrook, Janet T; Colvin, Ryan; van Natta, Mark L; Thorne, Jennifer E; Bardsley, Mark; Jabs, Douglas A

    2011-10-01

    To evaluate United States Public Health Service (USPHS) guidelines for discontinuing anticytomegalovirus (CMV) therapy in patients with AIDS who have immune recovery and quiescent retinitis after initiating highly active antiretroviral therapy. Cohort study of patients with CMV retinitis (Longitudinal Study of Ocular Complications of AIDS). Participants had CMV retinitis and CD4+ T-cell counts of 50 cells/μL or fewer enrolled from 1998 through 2009 who demonstrated sustained immune recovery (2 consecutive CD4+ T-cell counts of 100 cells/μL or more at least 6 months apart) and inactive retinitis. Participants were classified into 2 groups according to anti-CMV treatment after immune recover: (1) continued anti-CMV therapy and (2) discontinued therapy. We evaluated survival, visual acuity, and CMV retinitis activity; we used propensity scores to adjust for confounding factors for these analyses. Of 152 participants reviewed, 71 demonstrated immune recovery, 37 of whom discontinued therapy and 34 of whom continued therapy. At immune recovery, participants continuing therapy tended to be older (44 vs 40 years; P = .09), have bilateral retinitis (53% vs 32%; P = .10), and have lower CD4+ T-cell counts (148 vs 207 cells/μL; P < .001). There were no statistical differences in any of the clinical outcomes (death, retinitis progress, visual acuity, or incidence of bilateral retinitis). Both groups lost visual acuity during follow-up, on average 1.2 letters per year (P < .01). Discontinuation of anti-CMV therapy after immune recovery did not increase the risk of poor outcomes. These results support the current guidelines for discontinuation of anti-CMV therapy after achievement of sustained immune recovery. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. The Jeremiah Metzger Lecture: gene therapy for inherited disorders: from Christmas disease to Leber's amaurosis.

    PubMed

    High, Katherine A

    2009-01-01

    This paper will focus on recent developments in the field of gene therapy for inherited disorders. From a historical perspective, this Metzger lecture is a follow-on to one presented by Dr. William Kelley in 1987, entitled "Current Status of Human Gene Therapy" (Transactions Am Clin. Climatol. Assoc. 99:152-169) (1). In 1987, gene transfer studies in human subjects were yet to be undertaken; the first clinical studies, infusion of genetically modified autologous T cells into two young girls with ADA-SCID, would not take place until 1990 (2). Today's lecture will summarize progress since that time in one area, that of in vivo gene transfer for genetic disease. I will describe progress in two areas, gene therapy for the bleeding disorder hemophilia B, and for a subset of retinal degenerative disorders termed Leber's congenital amaurosis, due to mutations in the gene encoding retinal pigment epithelium-specific 65 kilodalton protein (RPE65). This lecture will demonstrate the interconnected nature of progress in these two areas, as careful delineation of the obstacles in hemophilia led to the realization that success could be achieved in Leber's.

  5. In Vivo Noninvasive Imaging for Gene Therapy

    PubMed Central

    2003-01-01

    Gene therapy is reaching a stage where some clinical benefits have been demonstrated on patients involved in phase I/II clinical trials. However, in many cases, the clinical benefit is hardly measurable and progress in the improvement of gene therapy formulations is hampered by the lack of objective clinical endpoints to measure transgene delivery and to quantitate transgene expression. However, these endpoints rely almost exclusively on the analysis of biopsies by molecular and histopathological methods. These methods provide only a limited picture of the situation. Therefore, there is a need for a technology that would allow precise, spacio-temporal measurement of gene expression on a whole body scale upon administration of the gene delivery vector. In the field of gene therapy, a considerable effort is being invested in the development of noninvasive imaging of gene expression and this review presents the various strategies currently being developed. PMID:12721514

  6. Gene Therapy Techniques for Peripheral Arterial Disease

    SciTech Connect

    Manninen, Hannu I.; Maekinen, Kimmo

    2002-03-15

    Somatic gene therapy is the introduction of new genetic material into selective somatic cells with resulting therapeutic benefits. Vascular wall and, subsequently, cardiovascular diseases have become an interesting target for gene therapy studies.Arteries are an attractive target for gene therapy since vascular interventions, both open surgical and endovascular, are well suited for minimally invasive, easily monitored gene delivery. Promising therapeutic effects have been obtained in animal models in preventing post-angioplasty restenosis and vein graft thickening, as well as increasing blood flow and collateral development in ischemic limbs.First clinical trials suggest a beneficial effect of vascular endothelial growth factor in achieving therapeutic angiogenesis in chronic limb ischemia and the efficacy of decoy oligonucleotides to prevent infrainguinal vein graft stenosis. However, further studies are mandatory to clarify the safety issues, to develop better gene delivery vectors and delivery catheters, to improve transgene expression, as well as to find the most effective and safe treatment genes.

  7. [Gene therapy: current status and promise].

    PubMed

    Kaneda, Y

    2001-04-01

    As of summer 2000, more than 400 protocols developed for human gene therapy have been reported, and there have been recent successful applications in some diseases such as arteriosclerosis obliterance, immunodeficiency X-1 (SCID-X1) and hemophilia B. However, complications have also occurred. Successful gene therapy is dependent on the development of an effective gene delivery system. One approach is development of chimeric vector systems that combine at least two different vector systems. However, a perfect vector system has not yet been constructed. Difficulties of in vivo gene transfer appear to result from resistance of living cells to invasion by foreign materials and from interference of cellular functions. We should reevaluate what barriers in tissues affect in vivo gene transfection and how to solve these problems for gene therapy. Moreover, in Japan, there should be more extensive preparation of social systems to promote clinical trials based on basic research.

  8. Biodegradable nanoparticles for gene therapy technology

    NASA Astrophysics Data System (ADS)

    Hosseinkhani, Hossein; He, Wen-Jie; Chiang, Chiao-Hsi; Hong, Po-Da; Yu, Dah-Shyong; Domb, Abraham J.; Ou, Keng-Liang

    2013-07-01

    Rapid propagations in materials technology together with biology have initiated great hopes in the possibility of treating many diseases by gene therapy technology. Viral and non-viral gene carriers are currently applied for gene delivery. Non-viral technology is safe and effective for the delivery of genetic materials to cells and tissues. Non-viral systems are based on plasmid expression containing a gene encoding a therapeutic protein and synthetic biodegradable nanoparticles as a safe carrier of gene. Biodegradable nanoparticles have shown great interest in drug and gene delivery systems as they are easy to be synthesized and have no side effect in cells and tissues. This review provides a critical view of applications of biodegradable nanoparticles on gene therapy technology to enhance the localization of in vitro and in vivo and improve the function of administered genes.

  9. State-of-the-art human gene therapy: part II. Gene therapy strategies and clinical applications.

    PubMed

    Wang, Dan; Gao, Guangping

    2014-09-01

    In Part I of this Review (Wang and Gao, 2014), we introduced recent advances in gene delivery technologies and explained how they have powered some of the current human gene therapy applications. In Part II, we expand the discussion on gene therapy applications, focusing on some of the most exciting clinical uses. To help readers to grasp the essence and to better organize the diverse applications, we categorize them under four gene therapy strategies: (1) gene replacement therapy for monogenic diseases, (2) gene addition for complex disorders and infectious diseases, (3) gene expression alteration targeting RNA, and (4) gene editing to introduce targeted changes in host genome. Human gene therapy started with the simple idea that replacing a faulty gene with a functional copy can cure a disease. It has been a long and bumpy road to finally translate this seemingly straightforward concept into reality. As many disease mechanisms unraveled, gene therapists have employed a gene addition strategy backed by a deep knowledge of what goes wrong in diseases and how to harness host cellular machinery to battle against diseases. Breakthroughs in other biotechnologies, such as RNA interference and genome editing by chimeric nucleases, have the potential to be integrated into gene therapy. Although clinical trials utilizing these new technologies are currently sparse, these innovations are expected to greatly broaden the scope of gene therapy in the near future.

  10. STATE-OF-THE-ART HUMAN GENE THERAPY: PART II. GENE THERAPY STRATEGIES AND APPLICATIONS

    PubMed Central

    Wang, Dan; Gao, Guangping

    2015-01-01

    In Part I of this Review, we introduced recent advances in gene delivery technologies and explained how they have powered some of the current human gene therapy applications. In Part II, we expand the discussion on gene therapy applications, focusing on some of the most exciting clinical uses. To help readers to grasp the essence and to better organize the diverse applications, we categorize them under four gene therapy strategies: (1) gene replacement therapy for monogenic diseases, (2) gene addition for complex disorders and infectious diseases, (3) gene expression alteration targeting RNA, and (4) gene editing to introduce targeted changes in host genome. Human gene therapy started with the simple idea that replacing a faulty gene with a functional copy can cure a disease. It has been a long and bumpy road to finally translate this seemingly straightforward concept into reality. As many disease mechanisms unraveled, gene therapists have employed a gene addition strategy backed by a deep knowledge of what goes wrong in diseases and how to harness host cellular machinery to battle against diseases. Breakthroughs in other biotechnologies, such as RNA interference and genome editing by chimeric nucleases, have the potential to be integrated into gene therapy. Although clinical trials utilizing these new technologies are currently sparse, these innovations are expected to greatly broaden the scope of gene therapy in the near future. PMID:25227756

  11. Mutation Screening of Multiple Genes in Spanish Patients with Autosomal Recessive Retinitis Pigmentosa by Targeted Resequencing

    PubMed Central

    González-del Pozo, María; Borrego, Salud; Barragán, Isabel; Pieras, Juan I.; Santoyo, Javier; Matamala, Nerea; Naranjo, Belén; Dopazo, Joaquín; Antiñolo, Guillermo

    2011-01-01

    Retinitis Pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. RP is the leading cause of visual loss in individuals younger than 60 years, with a prevalence of about 1 in 4000. The molecular genetic diagnosis of autosomal recessive RP (arRP) is challenging due to the large genetic and clinical heterogeneity. Traditional methods for sequencing arRP genes are often laborious and not easily available and a screening technique that enables the rapid detection of the genetic cause would be very helpful in the clinical practice. The goal of this study was to develop and apply microarray-based resequencing technology capable of detecting both known and novel mutations on a single high-throughput platform. Hence, the coding regions and exon/intron boundaries of 16 arRP genes were resequenced using microarrays in 102 Spanish patients with clinical diagnosis of arRP. All the detected variations were confirmed by direct sequencing and potential pathogenicity was assessed by functional predictions and frequency in controls. For validation purposes 4 positive controls for variants consisting of previously identified changes were hybridized on the array. As a result of the screening, we detected 44 variants, of which 15 are very likely pathogenic detected in 14 arRP families (14%). Finally, the design of this array can easily be transformed in an equivalent diagnostic system based on targeted enrichment followed by next generation sequencing. PMID:22164218

  12. Mutation spectrum of the rhodopsin gene among patients with autosomal dominant retinitis pigmentosa

    SciTech Connect

    Dryja, T.P.; Han, L.B.; Cowley, G.S.; McGee, T.L.; Berson, E.L. )

    1991-10-15

    The authors searched for point mutations in every exon of the rhodopsin gene in 150 patients from separate families with autosomal dominant retinitis pigmentosa. Including the 4 mutations the authors reported previously, they found a total of 17 different mutations that correlate with the disease. Each of these mutations is a single-base substitution corresponding to a single amino acid substitution. Based on current models for the structure of rhodopsin, 3 of the 17 mutant amino acids are normally located on the cytoplasmic side of the protein, 6 in transmembrane domains, and 8 on the intradiscal side. Forty-three of the 150 patients (29%) carry 1 of these mutations, and no patient has more than 1 mutation. In every family with a mutation so far analyzed, the mutation cosegregates with the disease. They found one instance of a mutation in an affected patient that was absent in both unaffected parents (i.e., a new germ-line mutation), indicating that some isolate cases of retinitis pigmentosa carry a mutation of the rhodopsin gene.

  13. Genes associated with retinitis pigmentosa and allied diseases are frequently mutated in the general population.

    PubMed

    Nishiguchi, Koji M; Rivolta, Carlo

    2012-01-01

    Retinitis pigmentosa and other hereditary retinal degenerations (HRD) are rare genetic diseases leading to progressive blindness. Recessive HRD are caused by mutations in more than 100 different genes. Laws of population genetics predict that, on a purely theoretical ground, such a high number of genes should translate into an extremely elevated frequency of unaffected carriers of mutations. In this study we estimate the proportion of these individuals within the general population, via the analyses of data from whole-genome sequencing. We screened complete and high-quality genome sequences from 46 control individuals from various world populations for HRD mutations, using bioinformatic tools developed in-house. All mutations detected in silico were validated by Sanger sequencing. We identified clear-cut, null recessive HRD mutations in 10 out of the 46 unaffected individuals analyzed (∼22%). Based on our data, approximately one in 4-5 individuals from the general population may be a carrier of null mutations that are responsible for HRD. This would be the highest mutation carrier frequency so far measured for a class of Mendelian disorders, especially considering that missenses and other forms of pathogenic changes were not included in our assessment. Among other things, our results indicate that the risk for a consanguineous couple of generating a child with a blinding disease is particularly high, compared to other genetic conditions.

  14. Novel deletions involving the USH2A gene in patients with Usher syndrome and retinitis pigmentosa

    PubMed Central

    García-García, Gema; Jaijo, Teresa; Aparisi, Maria J.; Larrieu, Lise; Faugère, Valérie; Blanco-Kelly, Fiona; Ayuso, Carmen; Roux, Anne-Francoise; Millán, José M.

    2014-01-01

    Purpose The aim of the present work was to identify and characterize large rearrangements involving the USH2A gene in patients with Usher syndrome and nonsyndromic retinitis pigmentosa. Methods The multiplex ligation-dependent probe amplification (MLPA) technique combined with a customized array-based comparative genomic hybridization (aCGH) analysis was applied to 40 unrelated patients previously screened for point mutations in the USH2A gene in which none or only one pathologic mutation was identified. Results We detected six large deletions involving USH2A in six out of the 40 cases studied. Three of the patients were homozygous for the deletion, and the remaining three were compound heterozygous with a previously identified USH2A point mutation. In five of these cases, the patients displayed Usher type 2, and the remaining case displayed nonsyndromic retinitis pigmentosa. The exact breakpoint junctions of the deletions found in USH2A in four of these cases were characterized. Conclusions Our study highlights the need to develop improved efficient strategies of mutation screening based upon next generation sequencing (NGS) that reduce cost, time, and complexity and allow simultaneous identification of all types of disease-causing mutations in diagnostic procedures. PMID:25352746

  15. Cancer suicide gene therapy: a patent review.

    PubMed

    Navarro, Saúl Abenhamar; Carrillo, Esmeralda; Griñán-Lisón, Carmen; Martín, Ana; Perán, Macarena; Marchal, Juan Antonio; Boulaiz, Houria

    2016-09-01

    Cancer is considered the second leading cause of death worldwide despite the progress made in early detection and advances in classical therapies. Advancing in the fight against cancer requires the development of novel strategies, and the suicide gene transfer to tumor cells is providing new possibilities for cancer therapy. In this manuscript, authors present an overview of suicide gene systems and the latest innovations done to enhance cancer suicide gene therapy strategies by i) improving vectors for targeted gene delivery using tissue specific promoter and receptors; ii) modification of the tropism; and iii) combining suicide genes and/or classical therapies for cancer. Finally, the authors highlight the main challenges to be addressed in the future. Even if many efforts are needed for suicide gene therapy to be a real alternative for cancer treatment, we believe that the significant progress made in the knowledge of cancer biology and characterization of cancer stem cells accompanied by the development of novel targeted vectors will enhance the effectiveness of this type of therapeutic strategy. Moreover, combined with current treatments, suicide gene therapy will improve the clinical outcome of patients with cancer in the future.

  16. Targeted Gene Therapies: Tools, Applications, Optimization

    PubMed Central

    Humbert, Olivier; Davis, Luther; Maizels, Nancy

    2012-01-01

    Many devastating human diseases are caused by mutations in a single gene that prevent a somatic cell from carrying out its essential functions, or by genetic changes acquired as a result of infectious disease or in the course of cell transformation. Targeted gene therapies have emerged as potential strategies for treatment of such diseases. These therapies depend upon rare-cutting endonucleases to cleave at specific sites in or near disease genes. Targeted gene correction provides a template for homology-directed repair, enabling the cell's own repair pathways to erase the mutation and replace it with the correct sequence. Targeted gene disruption ablates the disease gene, disabling its function. Gene targeting can also promote other kinds of genome engineering, including mutation, insertion, or gene deletion. Targeted gene therapies present significant advantages compared to approaches to gene therapy that depend upon delivery of stably expressing transgenes. Recent progress has been fueled by advances in nuclease discovery and design, and by new strategies that maximize efficiency of targeting and minimize off-target damage. Future progress will build on deeper mechanistic understanding of critical factors and pathways. PMID:22530743

  17. Gene Therapy for Diseases and Genetic Disorders

    MedlinePlus

    ... notable advancements are the following: Gene Therapy for Genetic Disorders Severe Combined Immune Deficiency (ADA-SCID) ADA- ... in preclinical animal models of this disease. Other genetic disorders After many years of laboratory and preclinical ...

  18. Gene Therapy: A Paradigm Shift in Dentistry

    PubMed Central

    Siddique, Nida; Raza, Hira; Ahmed, Sehrish; Khurshid, Zohaib; Zafar, Muhammad Sohail

    2016-01-01

    Gene therapy holds a promising future for bridging the gap between the disciplines of medicine and clinical dentistry. The dynamic treatment approaches of gene therapy have been advancing by leaps and bounds. They are transforming the conventional approaches into more precise and preventive ones that may limit the need of using drugs and surgery. The oral cavity is one of the most accessible areas for the clinical applications of gene therapy for various oral tissues. The idea of genetic engineering has become more exciting due to its advantages over other treatment modalities. For instance, the body is neither subjected to an invasive surgery nor deep wounds, nor is it susceptible to systemic effects of drugs. The aim of this article is to review the gene therapy applications in the field of dentistry. In addition, therapeutic benefits in terms of treatment of diseases, minimal invasion and maximum outcomes have been discussed. PMID:27834914

  19. Gene Therapy: A Paradigm Shift in Dentistry.

    PubMed

    Siddique, Nida; Raza, Hira; Ahmed, Sehrish; Khurshid, Zohaib; Zafar, Muhammad Sohail

    2016-11-10

    Gene therapy holds a promising future for bridging the gap between the disciplines of medicine and clinical dentistry. The dynamic treatment approaches of gene therapy have been advancing by leaps and bounds. They are transforming the conventional approaches into more precise and preventive ones that may limit the need of using drugs and surgery. The oral cavity is one of the most accessible areas for the clinical applications of gene therapy for various oral tissues. The idea of genetic engineering has become more exciting due to its advantages over other treatment modalities. For instance, the body is neither subjected to an invasive surgery nor deep wounds, nor is it susceptible to systemic effects of drugs. The aim of this article is to review the gene therapy applications in the field of dentistry. In addition, therapeutic benefits in terms of treatment of diseases, minimal invasion and maximum outcomes have been discussed.

  20. Progression of Retinal Pigment Epithelial Atrophy in Antiangiogenic Therapy of Neovascular Age-Related Macular Degeneration

    PubMed Central

    Schütze, Christopher; Wedl, Manuela; Baumann, Bernhard; Pircher, Michael; Hitzenberger, Christoph K.; Schmidt-Erfurth, Ursula

    2015-01-01

    Purpose To monitor retinal pigment epithelial (RPE) atrophy progression during antiangiogenic therapy of neovascular age-related macular degeneration (AMD) over 2 years using polarization-sensitive optical coherence tomography (OCT). Design Prospective interventional case series. Methods setting: Clinical practice. study population: Thirty patients (31 eyes) with treatment-naïve neovascular AMD. observation procedures: Standard intravitreal therapy (0.5 mg ranibizumab) was administered monthly during the first year and pro re nata (PRN; as-needed) during the second year. Spectral-domain (SD) OCT and polarization-sensitive OCT (selectively imaging the RPE) examinations were performed at baseline and at 1, 3, 6, 12, and 24 months using a standardized protocol. RPE-related changes were evaluated using a semi-automated polarization-sensitive OCT segmentation algorithm and correlated with SD OCT and fundus autofluorescence (FAF) findings. main outcome measures: RPE response, geographic atrophy (GA) progression. Results Atrophic RPE changes included RPE thinning, RPE porosity, focal RPE atrophy, and development of GA. Early RPE loss (ie, RPE porosity, focal atrophy) increased progressively during initial monthly treatment and remained stable during subsequent PRN-based therapy. GA developed in 61% of eyes at month 24. Mean GA area increased from 0.77 mm2 at 12 months to 1.10 mm2 (standard deviation = 1.09 mm2) at 24 months. Reactive accumulation of RPE-related material at the lesion borders increased until month 3 and subsequently decreased. Conclusions Progressive RPE atrophy and GA developed in the majority of eyes. RPE migration signifies certain RPE plasticity. Polarization-sensitive OCT specifically images RPE-related changes in neovascular AMD, contrary to conventional imaging methods. Polarization-sensitive OCT allows for precisely monitoring the sequence of RPE-related morphologic changes. PMID:25769245

  1. Retinitis pigmentosa and allied conditions today: a paradigm of translational research

    PubMed Central

    2010-01-01

    Monogenic human retinal dystrophies are a group of disorders characterized by progressive loss of photoreceptor cells leading to visual handicap. Retinitis pigmentosa is a type of retinal dystrophy where degeneration of rod photoreceptors occurs at the early stages. At present, there are no available effective therapies to maintain or improve vision in patients affected with retinitis pigmentosa, but post-genomic studies are allowing the development of potential therapeutic approaches. This review summarizes current knowledge on genes that have been identified to be responsible for retinitis pigmentosa, the involvement of these genes in the different forms of the disorder, the role of the proteins encoded by these genes in retinal function, the utility of genotyping, and current efforts to develop novel therapies. PMID:20519033

  2. Combination Systemic and Intravitreal Antiviral Therapy in The Management of Acute Retinal Necrosis Syndrome (An American Ophthalmological Society Thesis)

    PubMed Central

    Flaxel, Christina J.; Yeh, Steven; Lauer, Andreas K.

    2013-01-01

    Purpose: To compare the outcomes of combination systemic and intravitreal antiviral therapy vs systemic antiviral therapy alone for treating acute retinal necrosis syndrome (ARN). We hypothesize that combination therapy might result in superior visual acuity (VA) and retinal detachment (RD) outcomes vs traditional systemic antiviral therapy alone. Methods: A retrospective, interventional, comparative single-center study of patients with ARN. We reviewed demographic data, herpesvirus diagnoses, polymerase chain reaction (PCR) results, VA, RD, and the use of systemic and intravitreal antiviral therapy. Outcome measures included VA improvement by 2 or more lines, severe visual loss, VA ≤20/200, and RD. Results: We studied 29 eyes of 24 patients, treated from 1987 through 2009. Mean age was 42.6 years and mean follow-up was 44.0 months. Twelve patients (14 eyes) were treated with combined systemic and intravitreal antiviral therapy and 12 patients (15 eyes) with systemic therapy alone. Kaplan-Meier survival analysis revealed that patients receiving combination intravitreal and systemic antiviral therapy were more likely to have VA improved by 2 lines or greater (P=.006). Patients receiving combination therapy also showed a decreased incidence of progression to severe visual loss (0.13/patient-years [PY]) compared to patients receiving systemic therapy alone (0.54/PY, P=.02) and had decreased incidence of RD (0.29/PY vs 0.74/PY, P=.03). Conclusions: Combination oral and intravitreal antiviral therapy may improve visual and functional outcomes in patients with ARN. Clinicians should consider prompt administration of combination systemic and intravitreal antiviral therapy as first-line treatment for patients with clinical features of ARN. PMID:24385671

  3. Gene Therapy for Post-Traumatic Osteoarthritis

    DTIC Science & Technology

    2015-10-01

    chronic, degenerative, often crippling disease that primarily affects large weight bearing joints. There is strong evidence that interleukin - 1 (IL- 1 ) is a...Osteoarthritis (OA) Gene Therapy Equine Adeno-Associated Virus (AAV) Interleukin - 1 Receptor Antagonist (IL-1Ra) Post-traumatic OA (PTOA) Self...AD______________ AWARD NUMBER: W81XWH-14- 1 -0498 TITLE: Gene Therapy for Post-Traumatic Osteoarthritis PRINCIPAL INVESTIGATOR: Steven C

  4. Early Gene Expression Changes in the Retinal Ganglion Cell Layer of a Rat Glaucoma Model

    PubMed Central

    Guo, Ying; Johnson, Elaine C.; Cepurna, William O.; Dyck, Jennifer A.; Doser, Tom

    2011-01-01

    Purpose. To identify patterns of early gene expression changes in the retinal ganglion cell layer (GCL) of a rodent model of chronic glaucoma. Methods. Prolonged elevation of intraocular pressure (IOP) was produced in rats by episcleral vein injection of hypertonic saline (N = 30). GCLs isolated by laser capture microdissection were grouped by grading of the nerve injury (<25% axon degeneration for early injury; >25% for advanced injury). Gene expression was determined by cDNA microarray of independent GCL RNA samples. Quantitative PCR (qPCR) was used to further examine the expression of selected genes. Results. By array analysis, 533 GCL genes (225 up, 308 down) were significantly regulated in early injury. Compared to only one major upregulated gene class of metabolism regulation, more were downregulated, including mitochondria, ribosome, proteasome, energy pathways, protein synthesis, protein folding, and synaptic transmission. qPCR confirmed an early upregulation of Atf3. With advanced injury, 1790 GCL genes were significantly regulated (997 up, 793 down). Altered gene categories included upregulated protein synthesis, immune response, and cell apoptosis and downregulated dendrite morphogenesis and axon extension. Of all the early changed genes, 50% were not present in advanced injury. These uniquely affected genes were mainly associated with upregulated transcription regulation and downregulated protein synthesis. Conclusions. Early GCL gene responses to pressure-induced injury are characterized by an upregulation of Atf3 and extensive downregulation in genes associated with cellular metabolism and neuronal functions. Most likely, these changes represent those specific to RGCs and are thus potentially important for enhancing RGC survival in glaucoma. PMID:21051717

  5. Transcriptional Profile Analysis of RPGRORF15 Frameshift Mutation Identifies Novel Genes Associated with Retinal Degeneration

    PubMed Central

    Genini, Sem; Zangerl, Barbara; Slavik, Julianna; Acland, Gregory M.; Beltran, William A.

    2010-01-01

    Purpose. To identify genes and molecular mechanisms associated with photoreceptor degeneration in a canine model of XLRP caused by an RPGR exon ORF15 microdeletion. Methods. Expression profiles of mutant and normal retinas were compared by using canine retinal custom cDNA microarrays. qRT-PCR, Western blot analysis, and immunohistochemistry (IHC) were applied to selected genes, to confirm and expand the microarray results. Results. At 7 and 16 weeks, respectively, 56 and 18 transcripts were downregulated in the mutant retinas, but none were differentially expressed (DE) at both ages, suggesting the involvement of temporally distinct pathways. Downregulated genes included the known retina-relevant genes PAX6, CHML, and RDH11 at 7 weeks and CRX and SAG at 16 weeks. Genes directly or indirectly active in apoptotic processes were altered at 7 weeks (CAMK2G, NTRK2, PRKCB, RALA, RBBP6, RNF41, SMYD3, SPP1, and TUBB2C) and 16 weeks (SLC25A5 and NKAP). Furthermore, the DE genes at 7 weeks (ELOVL6, GLOD4, NDUFS4, and REEP1) and 16 weeks (SLC25A5 and TARS2) are related to mitochondrial functions. qRT-PCR of 18 genes confirmed the microarray results and showed DE of additional genes not on the array. Only GFAP was DE at 3 weeks of age. Western blot and IHC analyses also confirmed the high reliability of the transcriptomic data. Conclusions. Several DE genes were identified in mutant retinas. At 7 weeks, a combination of nonclassic anti- and proapoptosis genes appear to be involved in photoreceptor degeneration, whereas at both 7 and 16 weeks, the expression of mitochondria-related genes indicates that they may play a relevant role in the disease process. PMID:20574030

  6. Magnetic nanoparticles: Applications in gene delivery and gene therapy.

    PubMed

    Majidi, Sima; Zeinali Sehrig, Fatemeh; Samiei, Mohammad; Milani, Morteza; Abbasi, Elham; Dadashzadeh, Kianoosh; Akbarzadeh, Abolfazl

    2016-06-01

    Gene therapy is defined as the direct transfer of genetic material to tissues or cells for the treatment of inherited disorders and acquired diseases. For gene delivery, magnetic nanoparticles (MNPs) are typically combined with a delivery platform to encapsulate the gene, and promote cell uptake. Delivery technologies that have been used with MNPs contain polymeric, viral, as well as non-viral platforms. In this review, we focus on targeted gene delivery using MNPs.

  7. Human Studies of Angiogenic Gene Therapy

    PubMed Central

    Gupta, Rajesh; Tongers, Jörn; Losordo, Douglas W.

    2009-01-01

    Despite significant advances in medical, interventional, and surgical therapy for coronary and peripheral arterial disease, the burden of these illnesses remains high. To address this unmet need, the science of therapeutic angiogenesis has been evolving for almost two decades. Early pre-clinical studies and phase I clinical trials achieved promising results with growth factors administered as recombinant proteins or as single-agent gene therapies, and data accumulated through 10 years of clinical trials indicate that gene therapy has an acceptable safety profile. However, more rigorous phase II and phase III clinical trials have failed to unequivocally demonstrate that angiogenic agents are beneficial under the conditions and in the patients studied to date. Investigators have worked to understand the biology of the vascular system and to incorporate their findings into new treatments for patients with ischemic disease. Recent gene- and cell-therapy trials have demonstrated the bioactivity of several new agents and treatment strategies. Collectively, these observations have renewed interest in the mechanisms of angiogenesis and deepened our understanding of the complexity of vascular regeneration. Gene therapy that incorporates multiple growth factors, approaches that combine cell and gene therapy, and the administration of "master switch" agents that activate numerous downstream pathways are among the credible and plausible steps forward. In this review, we will examine the clinical development of angiogenic therapy, summarize several of the lessons learned during the conduct of these trials, and suggest how this prior experience may guide the conduct of future preclinical investigations and clinical trials. PMID:19815827

  8. Gene delivery to mitotic and postmitotic photoreceptors via compacted DNA nanoparticles results in improved phenotype in a mouse model of retinitis pigmentosa.

    PubMed

    Cai, Xue; Conley, Shannon M; Nash, Zack; Fliesler, Steven J; Cooper, Mark J; Naash, Muna I

    2010-04-01

    The purpose of the present study was to test the therapeutic efficiency and safety of compacted-DNA nanoparticle-mediated gene delivery into the subretinal space of a juvenile mouse model of retinitis pigmentosa. Nanoparticles containing the mouse opsin promoter and wild-type mouse Rds gene were injected subretinally into mice carrying a haploinsufficiency mutation in the retinal degeneration slow (rds(+ or -)) gene at postnatal day (P)5 and 22. Control mice were either injected with saline, injected with uncompacted naked plasmid DNA carrying the Rds gene, or remained untreated. Rds mRNA levels peaked at postinjection day 2 to 7 (PI-2 to PI-7) for P5 injections, stabilized at levels 2-fold higher than in uninjected controls for both P5 and P22 injections, and remained elevated at the latest time point examined (PI-120). Rod function (measured by electroretinography) showed modest but statistically significant improvement compared with controls after both P5 and P22 injections. Cone function in nanoparticle-injected eyes reached wild-type levels for both ages of injections, indicating full prevention of cone degeneration. Ultrastructural examination at PI-120 revealed significant improvement in outer segment structures in P5 nanoparticle-injected eyes, while P22 injection had a modest structural improvement. There was no evidence of macrophage activation or induction of IL-6 or TNF-alpha mRNA in P5 or P22 nanoparticle-dosed eyes at either PI-2 or PI-30. Thus, compacted-DNA nanoparticles can efficiently and safely drive gene expression in both mitotic and postmitotic photoreceptors and retard degeneration in this model. These findings, using a clinically relevant treatment paradigm, illustrate the potential for application of nanoparticle-based gene replacement therapy for treatment of human retinal degenerations.-Cai, X., Conley, S. M., Nash, Z., Fliesler, S. J., Cooper, M. J., Naash, M. I. Gene delivery to mitotic and postmitotic photoreceptors via compacted DNA

  9. Gene therapy for human genetic disease?

    PubMed

    Friedmann, T; Roblin, R

    1972-03-03

    In our view, gene therapy may ameliorate some human genetic diseases in the future. For this reason, we believe that research directed at the development of techniques for gene therapy should continue. For the foreseeable future, however, we oppose any further attempts at gene therapy in human patients because (i) our understanding of such basic processes as gene regulation and genetic recombination in human cells is inadequate; (ii) our understanding of the details of the relation between the molecular defect and the disease state is rudimentary for essentially all genetic diseases; and (iii) we have no information on the short-range and long-term side effects of gene therapy. We therefore propose that a sustained effort be made to formulate a complete set of ethicoscientific criteria to guide the development and clinical application of gene therapy techniques. Such an endeavor could go a long way toward ensuring that gene therapy is used in humans only in those instances where it will prove beneficial, and toward preventing its misuse through premature application. Two recent papers have provided new demonstrations of directed genetic modification of mammalian cells. Munyon et al. (44) restored the ability to synthesize the enzyme thymidine kinase to thymidine kinase-deficient mouse cells by infection with ultraviolet-irradiated herpes simplex virus. In their experiments the DNA from herpes simplex virus, which contains a gene coding for thymidine kinase, may have formed a hereditable association with the mouse cells. Merril et al. (45) reported that treatment of fibroblasts from patients with galactosemia with exogenous DNA caused increased activity of a missing enzyme, alpha-D-galactose-l-phosphate uridyltransferase. They also provided some evidence that the change persisted after subculturing the treated cells. If this latter report can be confirmed, the feasibility of directed genetic modification of human cells would be clearly demonstrated, considerably