Exploring the pathophysiology and treatment of LCHADD retinopathy

探索 LCHADD 视网膜病变的病理生理学和治疗

• 批准号: 10470841
• 负责人: Melanie B Gillingham
• 金额: $ 37.35万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10470841
• 关键词: 3-Hydroxyacyl-CoA dehydrogenase; Address; Animals; Blindness; Blood; CRISPR/Cas technology; Cell Culture Techniques; Cell Differentiation process; Cells; Cessation of life; Child; Childhood; Chronic; Coculture Techniques; Color Visions; Complication; Defect; Deterioration; Development; Diet therapy; Disease; Early Diagnosis; Early Intervention; Early treatment; Electroretinography; Exhibits; Experimental Models; Fatty Acids; Fibroblasts; Functional disorder; Future; Gene Transfer; Genes; Genetic; Goals; Hepatic; Hydrogen Peroxide; Impairment; In Vitro; Ketones; Knock-in; Light; Lipids; Liver; Mediating; Metabolic; Mitochondria; Modality; Modeling; Molecular; Mus; Muscle; Mutation; Natural History; Neonatal Screening; Organ; Outcome; Oxidative Stress; Oxides; Oxidoreductase; Palmitates; Pathologic; Pathology; Patients; Peripheral; Phenotype; Photoreceptors; Pigments; Plasma; Point Mutation; Predisposition; Production; Protein Deficiency; Recombinant adeno-associated virus (rAAV); Retina; Retinal Degeneration; Retinal Diseases; Retinal Pigments; Retinal gene therapy; Role; Series; Structure; Structure of retinal pigment epithelium; Testing; Time; Toxic effect; Toxin; Vision; Visual Acuity; Wild Type Mouse; acylcarnitine; adeno-associated viral vector; cell type; design; experimental study; fatty acid oxidation; gene therapy; human disease; in vitro Model; induced pluripotent stem cell; macula; mouse model; mutant mouse model; novel; novel therapeutics; oxidation; oxidative damage; preservation; prevent; response; restoration; retinal damage; visual performance

Project Summary Progressive retinopathy with vision loss is a unique complication of Long-chain 3-Hydroxyacyl-CoA Dehydrogenase Deficiency (LCHADD) and mitochondrial Trifunctional Protein Deficiency (TFPD), rare genetic fatty acid oxidation (FAO) disorders. Gradual macular pigment clumping, followed by progressive deterioration of the retina occurs in almost all LCHADD patients beginning in childhood and progressing over time. This manifests initially as decreased night vision, progresses to loss of color vision, and ultimately to decreased central vision. While early diagnosis through newborn screening and sustained dietary therapy can slow progression, no successful treatment directed at retinopathy currently exists, and children with LCHADD/TFPD continue to suffer progressive blindness. Novel treatments for LCHADD-associated retinopathy are needed but appropriate experimental models have been lacking. We recently created 2 models of LCHADD-retinopathy; a murine knockin of c.1528G>C, the common mutation in the HADHA gene that causes LCHADD, and cultured RPE-like cells differentiated from induced pluripotent stem cells (iPSC) derived from patients' fibroblasts. The pathophysiology of LCHADD-associated retinopathy is not completely understood but begins with loss of retinal pigment epithelium (RPE). Two potential molecular mechanisms include; energy deficit due to decreased FAO to support normal RPE functions, or selective toxicity of accumulating partially oxidized fatty acid metabolites. Children with lower blood concentrations of LCHADD-specific 3-hydroxy-acylcarnitines have preserved retinal function implying that retinal damage may be mediated through accumulation of toxic fatty acid intermediates. If so, then gene therapy directed toward a peripheral organ such as muscle or liver could lower circulating toxic metabolites, prevent retinal degeneration, and address other LCHADD-associated complications. Alternatively, retinal preservation may require the restoration of LCHAD activity directly in RPE, and circulating acylcarnitines are simply a marker of partial FAO in the retina. We will use our 2 models of LCHADD-retinopathy to test which approach will prevent RPE dysfunction and retinal degeneration. LCHADD-RPE exhibit decreased ability to oxidize palmitate, accumulated acylcarnitines and neutral lipids, and increased susceptibility to H2O2 oxidative stress in comparison to wild type (WT) RPE. We propose a series of experiments to test LCHADD-associated RPE alterations such as lipid processing and sensitivity to H2O2 treatment under different FAO conditions compared to WT RPE. Additionally, the LCHADD-mouse has decreased visual performance and electroretinogram (ERG) responses compared to WT mice. Our goal is to characterize the visual acuity, retinal structure and function of LCHADD mice and to test the effects of hepatic versus retinal directed gene therapy approaches. The outcome of these experiments will expand our understanding of LCHAD-specific pathology and provide the basis for a translational effort to treat LCHADD retinopathy, potentially with retinal gene therapy, a new treatment modality of which OHSU is a national leader.

项目概要 伴有视力丧失的进行性视网膜病变是长链 3-羟基酰基辅酶 A 的独特并发症 脱氢酶缺乏症 (LCHADD) 和线粒体三功能蛋白缺乏症 (TFPD)，罕见遗传性疾病 脂肪酸氧化（FAO）疾病。黄斑色素逐渐聚集，随后逐渐恶化 几乎所有 LCHADD 患者都从儿童时期开始出现视网膜损伤，并随着时间的推移而进展。这 最初表现为夜视力下降，进展为色觉丧失，最终表现为色觉下降 中心视野。虽然通过新生儿筛查和持续饮食治疗进行早期诊断可以减缓 进展，目前尚无针对视网膜病变的成功治疗方法，以及患有 LCHADD/TFPD 的儿童 继续遭受进行性失明。需要针对 LCHADD 相关视网膜病变的新疗法，但 一直缺乏合适的实验模型。我们最近创建了 2 个 LCHADD 视网膜病变模型；一个 c.1528G>C（HADHA 基因中导致 LCHADD 的常见突变）的小鼠敲入，并培养 RPE 样细胞由源自患者成纤维细胞的诱导多能干细胞 (iPSC) 分化而来。 LCHADD 相关视网膜病变的病理生理学尚未完全了解，但始于 视网膜色素上皮（RPE）损失。两种潜在的分子机制包括：由于能量不足 减少FAO以支持正常的RPE功能，或积累部分氧化脂肪的选择性毒性 酸性代谢物。血液中 LCHADD 特异性 3-羟基酰基肉碱浓度较低的儿童 保留的视网膜功能意味着视网膜损伤可能是通过有毒脂肪的积累介导的 酸中间体。如果是这样，那么针对肌肉或肝脏等外周器官的基因治疗可以 降低循环有毒代谢物，预防视网膜变性，并解决其他 LCHADD 相关问题 并发症。或者，视网膜保存可能需要直接在 RPE 中恢复 LCHAD 活性， 循环酰基肉碱只是视网膜中部分FAO的标记。我们将使用我们的 2 种型号 LCHADD-视网膜病变，测试哪种方法可以预防 RPE 功能障碍和视网膜变性。 LCHADD-RPE 表现出氧化棕榈酸酯、积累酰基肉碱和中性的能力下降 与野生型 (WT) RPE 相比，脂质含量增加，并且对 H2O2 氧化应激的敏感性增加。我们建议 一系列实验来测试 LCHADD 相关的 RPE 改变，例如脂质加工和对 与WT RPE 相比，不同FAO 条件下的H2O2 处理。此外，LCHADD 鼠标还具有 与 WT 小鼠相比，视觉表现和视网膜电图（ERG）反应下降。我们的目标是 表征 LCHADD 小鼠的视力、视网膜结构和功能，并测试肝脏的影响 与视网膜定向基因治疗方法相比。这些实验的结果将扩展我们的 了解 LCHAD 特异性病理学并为治疗 LCHADD 的转化工作提供基础 视网膜病变，可能采用视网膜基因疗法，这是一种新的治疗方式，OHSU 是该疗法的全国领先者。