Essential Role of Very Long Chain Fatty Acids in Retinal Function

极长链脂肪酸在视网膜功能中的重要作用

• 批准号: 10018024
• 负责人: Martin-Paul Agbaga
• 金额: $ 36.25万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-30 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10018024
• 关键词: Adolescent; Affect; Age-Months; Alleles; Animal Model; Ataxia; Attenuated; Biochemical Reaction; Birth; Blindness; Brain; Cell Culture Techniques; Cells; Cerebellum; Cessation of life; Child; Deformity; Dehydration; Development; Disease; Disease Progression; Dominant-Negative Mutation; Enzymes; Essential Fatty Acids; Exons; Fatty Acids; Film; Fish Oils; Gait abnormality; Genes; Goals; Health; Human; In Vitro; Japanese Population; Knock-in; Knock-out; Life; Long-Evans Rats; Macular degeneration; Maintenance; Modeling; Molecular; Mus; Mutation; Neonatal; Nerve Degeneration; Outcome; Pathologic; Pathology; Patients; Permeability; Phenotype; Photoreceptors; Point Mutation; Polyunsaturated Fatty Acids; Property; Proteins; Public Health; Quality Control; Quality of life; Rattus; Retina; Retinal Degeneration; Role; Saturated Fatty Acids; Seizures; Skin; Spinocerebellar Ataxias; Stargardt' s disease; Structure; Testing; Testis; Therapeutic; Tissues; Very Long Chain Fatty Acid; Waxes; Work; autosomal dominant mutation; biophysical properties; cohort; design; early childhood; experimental study; fatty acid biosynthesis; human disease; in vivo; insight; keratinocyte; macula; macular dystrophy; meibomian gland; mortality; motor impairment; mutant; novel; skin lesion; sperm cell; targeted treatment; therapeutic target; tissue culture

Abstract Very long chain fatty acids (VLC-FA, ≥ C28) are synthesized by the Elongation of Very Long Chain Fatty Acids-4 (ELOVL4) enzyme and are essential for life such that depletion of tissue VLC-FA (due to knockout of ELOVL4) causes neonatal lethality. The ELOVL4 protein is expressed in the retina, Meibomian glands, brain, skin, and testes. In each of these tissues, the enzyme makes two different classes of VLC-FA. One class is VLC-saturated fatty acids (VLC-SFA) that are found mainly in the skin, brain, Meibomian glands and tear film. The other is VLC-polyunsaturated fatty acids (VLC-PUFA) that are found in the retina, testes and sperm. Since VLC-FA are essential for the normal function of these tissues, mutations in ELOVL4 cause distinct tissue- specific disorders like Stargardt-like macular dystrophy (STGD3), spinocerebellar ataxia-34 (SCA34), skin pathologies, seizures and death. However, the mechanisms by which one tissue makes mainly VLC-SFA and the other VLC-PUFA, and how the VLC-FA exert their importance in each tissue remain unknown. We seek to understand the molecular basis of this phenomenon with the goal of developing therapeutic targets for attenuating disease progression. Our lab and others have shown that conditional deletion of retinal Elovl4 or expression of the mutant Elovl4 leads to depletion of VLC-SFA and VLC-PUFA, which affect retinal structure and function. We also showed that the STGD3 mutant ELOVL4 lacks VLC-PUFA biosynthesis and exerts a dominant negative effect on wild type ELOVL4 (WT ELOVL4) in vitro and in vivo causing decreased VLC-FA biosynthesis. These suggest that VLC-FA are necessary for maintenance of photoreceptor health and function. To understand how one set of mutations causes vision loss and another causes ataxia, we successfully generated a Long Evans (LE) rat knock-in model of the SCA34 ELOVL4 mutation (c.736T>G) that recapitulates the human disorder. Consequently, we now have animal models of STGD3 and SCA34. We hypothesize that tissue-specific factors determine which type of fatty acid is made in specific tissues and that the pathological differences found in patients with STGD3 and SCA34 result from differences in the types of VLC-FAs produced directly by the mutant enzymes or from effects of the mutant enzymes on VLC-FA produced by the wild type ELOVL4 enzyme. We propose two specific aims: 1) To determine how different ELOVL4-expressing tissues control the VLC-SFA and VLC-PUFA biosynthetic activity of ELOVL4. 2) To determine how the different ELOVL4 mutations affect the quality and quantity of the VLC-FA that they synthesize. The results would provide better mechanistic insight into the relative contributions of the depletion of VLC-FA and the mutant ELOVL4 in the progression of the mutant ELOVL4 disorders. This could potentially provide an immediate positive impact by paving the way for development of potential therapeutic approaches to rescue these disorders.

抽象的 很长的链脂肪酸（VLC-FA，≥C28）通过非常长的链脂肪的伸长来合成 酸-4（elovl4）酶，对生命至关重要，使组织VLC-FA的耗竭（由于敲除 Elovl4）引起新生儿致死性。 ELOVL4蛋白在视网膜，Meibomian网格，大脑， 皮肤和睾丸。在这些组织中的每一个中，酶生产两种不同类别的VLC-FA。一个课是 VLC饱和的脂肪酸（VLC-SFA）主要在皮肤，大脑，梅博米亚网格和撕裂膜中发现。 另一个是在视网膜，睾丸和精子中发现的VLC-饱和脂肪酸（VLC-PUFA）。自从 VLC-FA对于这些时间的正常功能至关重要，ELOVL4中的突变会导致不同的组织 特定疾病，例如类似Stargardt的黄斑营养不良症（STGD3），脊髓脑性共济失调-34（SCA34），皮肤 病理，癫痫发作和死亡。但是，一个组织主要使VLC-SFA和 另一个VLC-PUFA，以及VLC-FA如何在每个组织中施加重要性。我们寻求 了解这种现象的分子基础，目的是为 减弱疾病进展。我们的实验室和其他实验室表明，视网膜Elovl4或 突变体Elovl4的表达导致VLC-SFA和VLC-PUFA的耗竭，这会影响残余结构 和功能。我们还表明，STGD3突变体Elovl4缺乏VLC-PUFA生物合成并执行A 在体外和体内对野生型Elovl4（WT Elovl4）的主要负面影响，导致VLC-FA降低 生物合成。这些表明VLC-FA对于维持感光受体健康和功能是必需的。 要了解一组突变如何导致视力丧失和另一个原因引起共济失调，我们成功地 产生了SCA34 ElOVL4突变（c.736t> g）的长埃文斯（LE）大鼠敲门模型 概括人类障碍。因此，我们现在拥有STGD3和SCA34的动物模型。我们 假设组织特异性因素确定在特定组织中制造了哪种类型的脂肪酸，并且 在STGD3和SCA34患者中发现的病理差异是由于类型的差异而引起的 直接由突变酶或突变酶对VLC-FA的影响产生的VLC-FA 由野生型Elovl4酶产生。我们提出了两个具体目标：1）确定不同的不同 ELOVL4表达的组织控制ELOVL4的VLC-SFA和VLC-PUFA生物合成活性。 2）到 确定不同的ELOVL4突变如何影响它们的VLC-FA的质量和数量 合成。结果将为部署的相对贡献提供更好的机械洞察力 VLC-FA和突变体Elovl4疾病进展中的突变体Elovl4。这可能是可能的 通过粘贴开发潜在治疗方法的方式来提供直接的积极影响 营救这些疾病。