The mechanism of cone cell death in Retinitis Pigmentosa.
TL;DR: Compared with aqueous humor samples from control patients, those from patients with RP show significant elevation of carbonyl content on proteins indicating oxidative damage and a reduction in the ratio of reduced to oxidized glutathione indicating depletion of a major component of the antioxidant defense system from ongoing oxidative stress.
About: This article is published in Progress in Retinal and Eye Research.The article was published on 2017-09-01. It has received 197 citations till now. The article focuses on the topics: Rod cell & Oxidative stress.
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University of California, San Francisco1, Massachusetts Eye and Ear Infirmary2, Foundation Fighting Blindness3, University of Texas Health Science Center at Houston4, University of Florida5, Duke University6, Helen Wills Neuroscience Institute7, Vision Institute8, University of Pittsburgh9, Johns Hopkins University School of Medicine10, Rutgers University11
TL;DR: This research presents a novel and scalable approach, called “Smart Gene Regulation,” which aims to provide real-time information about the activity of the immune cells in the eyes of the visually-impaired.
Abstract: Inherited retinal degenerations (IRDs) represent a diverse group of progressive, visually debilitating diseases that can lead to blindness in which mutations in genes that are critical to retinal function lead to progressive photoreceptor cell death and associated vision loss. IRDs are genetically heterogeneous, with over 260 disease genes identified to date.1 The development of treatments and cures to modify the rate of disease progression has been limited to date, with some success of neurotrophic factor therapy and gene therapies reported from clinical trials.2–11 The best example of treatment success is gene augmentation therapy for IRD caused by mutations in the RPE65 gene, which recently received US Food and Drug Administration (FDA) approval, which in fact represented the first FDA-approved gene therapy (GT) for any genetically inherited disease.4–9 Recent developments in the IRD field have advanced understanding of the mechanisms responsible for vision loss, creating new opportunities to intervene in the course of disease by developing new therapeutic approaches. In 2013, a Delphi-style gathering of IRD experts led to the identification, by consensus, of top priorities to advance therapeutic efforts for IRDs, including the need for systematic genotyping, improved standardization of visual function testing, development of more rigorous and widespread data collection protocols, and increased data sharing.12 This document summarizes more recent advances in the IRD field and outlines specific knowledge gaps. These knowledge gaps present opportunities for further investigation to enable development of therapies that may slow down or prevent vision loss, or restore vision, in affected patients.
Atrophic age-related macular degeneration (AMD) is included among the target inherited retinal diseases of interest because first, understanding AMD may contribute to understanding of inherited macular diseases, and second, understanding of the genetics and mechanism of inherited macular degenerations may contribute to understanding of AMD.
146 citations
Cites background from "The mechanism of cone cell death in..."
...Studies of the noncell autonomous nature of cone cell death in rodcone degenerations has led to recognition of metabolic and oxidative stress in photoreceptor dysfunction and death.(29,30) These studies have also identified supportive factors such as RdCVF and NRF2 that could be used to develop nongene specific treatments that may be beneficial to groups of disorders that are caused by mutations in a variety of different genes and that could potentially also help at later stages of the disease process....
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Journal Article•
TL;DR: In this paper, the role of microglia as a contributor to photoreceptor degeneration in the rd10 mouse model of retinitis pigmentosa (RP) was explored.
Abstract: Retinitis pigmentosa (RP) is a photoreceptor-degenerative disease caused by various mutations and is characterized by death of rod photoreceptor cell followed by gradual death of cone photoreceptors. The molecular mechanisms that lead to rod and cone death are not yet fully understood. Neuroinflammation contributes to the progression of many chronic neurodegenerative disorders. However, it remains to be determined how microglia contribute to photoreceptor disruption in RP. In this study, we explored the role of microglia as a contributor to photoreceptor degeneration in the rd10 mouse model of RP. First, we demonstrated that microglia activation was an early alteration in RP retinas. Inhibition of microglia activation by minocycline reduced photoreceptor apoptosis and significantly improved retinal structure and function and visual behavior in rd10 mice. Second, we identified that minocycline exerted its neuroprotective effects through both anti-inflammatory and anti-apoptotic mechanisms. Third, we found that Cx3cr1 deficiency dysregulated microglia activation and subsequently resulted in increased photoreceptor vulnerability in rd10 mice, suggesting that the Cx3cl1/Cx3cr1 signaling pathway might protect against microglia neurotoxicity. We concluded that suppression of neuroinflammatory responses could be a potential treatment strategy aimed at improving photoreceptor survival in human RP.
134 citations
TL;DR: The metabolic needs of the neural retina profoundly influence blood vessel supply in development and in disease, and understanding the specific fuels used in the retina to generate ATP and supply building blocks for biosynthesis, as well as the vaso-proliferative response to the lack of fuel are also key to neurovascular development.
90 citations
TL;DR: An evaluation of the available literature reveals that a large group of patients suffering from hereditary photoreceptor degeneration carry mutations that are likely to trigger cGMP-dependent cell death, making this pathway a prime target for future therapy development.
81 citations
TL;DR: Current considerations regarding the administration of LuxturnaTM in the clinic are presented, becoming the first approved gene therapy product for a genetic disease in the USA and in the European Union.
66 citations
References
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TL;DR: It is proposed that superoxide dismutase may protect vascular tissue stimulated to produce superoxide and NO under pathological conditions by preventing the formation of peroxynitrite.
Abstract: Superoxide dismutase reduces injury in many disease processes, implicating superoxide anion radical (O2-.) as a toxic species in vivo. A critical target of superoxide may be nitric oxide (NO.) produced by endothelium, macrophages, neutrophils, and brain synaptosomes. Superoxide and NO. are known to rapidly react to form the stable peroxynitrite anion (ONOO-). We have shown that peroxynitrite has a pKa of 7.49 +/- 0.06 at 37 degrees C and rapidly decomposes once protonated with a half-life of 1.9 sec at pH 7.4. Peroxynitrite decomposition generates a strong oxidant with reactivity similar to hydroxyl radical, as assessed by the oxidation of deoxyribose or dimethyl sulfoxide. Product yields indicative of hydroxyl radical were 5.1 +/- 0.1% and 24.3 +/- 1.0%, respectively, of added peroxynitrite. Product formation was not affected by the metal chelator diethyltriaminepentaacetic acid, suggesting that iron was not required to catalyze oxidation. In contrast, desferrioxamine was a potent, competitive inhibitor of peroxynitrite-initiated oxidation because of a direct reaction between desferrioxamine and peroxynitrite rather than by iron chelation. We propose that superoxide dismutase may protect vascular tissue stimulated to produce superoxide and NO. under pathological conditions by preventing the formation of peroxynitrite.
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TL;DR: This review provides a comprehensive summary on the chemical properties of 4-hydroxyalkenals and malonaldehyde, the mechanisms of their formation and their occurrence in biological systems and methods for their determination, as well as the many types of biological activities described so far.
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TL;DR: The data support the idea of a "beneficial" role for bilirubin as a physiological, chain-breaking antioxidant.
Abstract: Bilirubin, the end product of heme catabolism in mammals, is generally regarded as a potentially cytotoxic, lipid-soluble waste product that needs to be excreted. However, it is here that bilirubin, at micromolar concentrations in vitro, efficiently scavenges peroxyl radicals generated chemically in either homogeneous solution or multilamellar liposomes. The antioxidant activity of bilirubin increases as the experimental concentration of oxygen is decreased from 20% (that of normal air) to 2% (physiologically relevant concentration). Furthermore, under 2% oxygen, in liposomes, bilirubin suppresses the oxidation more than alpha-tocopherol, which is regarded as the best antioxidant of lipid peroxidation. The data support the idea of a "beneficial" role for bilirubin as a physiological, chain-breaking antioxidant.
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TL;DR: This chapter discusses the methods used for the qualitative and quantitative determination of aldehydes in biological systems and focuses on 4-hydroxynonenal and malondialdehyde, which are in many instances the most abundant individual aldehyde resulting from lipid peroxidation.
Abstract: Publisher Summary This chapter discusses the methods used for the qualitative and quantitative determination of aldehydes in biological systems. It focuses on 4-hydroxynonenal (HNE) and malondialdehyde (MDA). 4-Hydroxynonenal is produced as a major product of the peroxidative decomposition of polyunsaturated fatty acids (PUFA) and possesses cytotoxic, hepatotoxic, mutagenic, and genoroxic properties. Increased levels of HNE are found in plasma and various organs under conditions of oxidative stress. In addition to HNE, lipid peroxidation generates many other aldehydes that may also be of toxicological significance. Malondialdehyde is in many instances the most abundant individual aldehyde resulting from lipid peroxidation, and its determination by thiobarbituric acid (TBA) is one of the most common assays in lipid peroxidation studies. In vitro MDA can alter proteins, DNA, RNA, and many other biomolecules. Recently, it has been demonstrated with monoclonal antibodies that malonaldehyde-altered protein occurs in atheroma of hyperlipidemic rabbits.
3,113 citations