Molecular and Cellular Mechanisms of the Lysosomal Storage Disease Cystinosis

溶酶体贮积病胱氨酸中毒的分子和细胞机制

• 批准号: 10434057
• 负责人: ANA MARIA CUERVO
• 金额: $ 72.53万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-09 至 2026-05-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10434057
• 关键词: Affect; Animal Model; Apoptosis; Autophagocytosis; Biochemical; Brain; Cell Compartmentation; Cell Death; Cell model; Cell physiology; Cells; Cellular biology; Cessation of life; Child; Chronic Kidney Failure; Clinical; Complement; Complementary therapies; Cysteamine; Cystine; Cystinosis; Data; Defect; Deterioration; Development; Disease; Down-Regulation; Event; Eye; Failure; Fanconi Syndrome; Functional disorder; Goals; Growth; Homeostasis; Human; Human Pathology; Impairment; Injury to Kidney; Kidney; LDL-Receptor Related Protein 2; Lead; Link; Liver; Lysosomal Storage Diseases; Lysosomes; Mediating; Membrane; Microscopy; Molecular; Molecular Chaperones; Mus; Mutation; Organ; Pathogenesis; Pathology; Pathway interactions; Patients; Pharmaceutical Chemistry; Predisposition; Proteins; Recycling; Regulation; Renal function; Research; Resolution; Role; Testing; Tissues; cell dedifferentiation; detection of nutrient; human disease; improved; improved functioning; in vivo; mutant; nephropathic cystinosis; nervous system disorder; novel; novel therapeutics; pediatrician; receptor; reconstitution; repaired; small molecule; tissue injury; trafficking; translational approach; young adult

SUMMARY Lysosomal function is crucial for cell homeostasis, autophagy, nutrient sensing, apoptosis and tissue remodeling. In lysosomal storage disorders (LSDs), characterized by genetic defects leading to anomalous accumulation of metabolites in lysosomes, cells are affected by lysosomal malfunction frequently leading to cell death. Cystinosis is a lysosomal storage disorder resulting from defects in the cystine transporter cystinosin (CTNS). Increased levels of intra-lysosomal cystine lead to cell malfunction and progressive tissue deterioration, which is especially manifested in kidneys. As with most LSDs, this leads to a slow but irreversible deterioration, organ dysfunction and early death. Patients with nephropathic cystinosis develop proximal tubule cell dedifferentiation, Fanconi syndrome and progressive renal injury, which are not corrected by the current therapy, cysteamine. Thus, cell malfunction and tissue failure occur despite cystine depletion, suggesting that cystine accumulation is not the only cause of all the defects observed in cystinosis. We recently revealed a defective mechanism of chaperone- mediated autophagy (CMA) in cystinosis. Defective CMA is directly linked to human disease, including kidney pathologies and neurological disorders. CMA defects in cystinosis are caused by mislocalization and downregulation of the only lysosomal CMA receptor, LAMP2A. Defective CMA activity correlates with high susceptibility to cell death in cystinosis. Importantly, the defect was not rescued by cystine depleting therapies supporting that it is independent of lysosomal overload. Our data highlight that CMA impairment is an important contributor to the pathogenesis of cystinosis and underline the need for new treatments to complement cystine- depletion therapies. Our research plan aims to elucidate the molecular and cellular mechanisms leading to abnormal CMA activity in cystinosis. We also propose translational approaches that utilize small-molecule activators of CMA to improve cellular function in cystinosis. Our Specific Aims are: Aim 1: To elucidate the molecular basis of the regulation of LAMP2A function in cystinosis. To this end, we will study the interplay between the CTNS protein and the CMA receptor LAMP2A and elucidate the mechanisms that mediate LAMP2A trafficking and destabilization at the lysosomal membrane in cystinosis. Aim 2: To determine the molecular basis of the regulation of CMA activity in cystinosis. We will study the mechanisms mediated by CTNS to regulate CMA function and will test the hypothesis that the rescue of CMA activity improves the function of proximal tubule cells from cystinotic patients. Aim 3: To utilize small-molecule CMA activators, in vivo, to improve renal function in cystinotic mice. We will correct cellular and renal function in cystinotic mice using CMA activators, alone, or in combination with cysteamine. Our research is highly significant because it aims to elucidate molecular mechanisms associated with a devastating human pathology and will help develop new therapies for the treatment of cystinosis and other human diseases.

概括 溶酶体功能对于细胞稳态、自噬、营养感应、细胞凋亡和组织重塑至关重要。 溶酶体贮积症 (LSD)，其特征是遗传缺陷导致异常积累 由于溶酶体中的代谢物，细胞受到溶酶体功能障碍的影响，经常导致细胞死亡。胱氨酸病 是一种由胱氨酸转运蛋白胱氨酸 (CTNS) 缺陷引起的溶酶体贮积症。增加 溶酶体内胱氨酸的水平会导致细胞功能障碍和进行性组织恶化，尤其是 表现在肾脏。与大多数 LSD 一样，这会导致缓慢但不可逆转的恶化、器官功能障碍 和早逝。肾病性胱氨酸沉着症患者出现近端小管细胞去分化，Fanconi 综合征和进行性肾损伤，目前的疗法半胱胺无法纠正这些症状。因此，细胞 尽管胱氨酸耗尽，但仍会发生功能障碍和组织衰竭，这表明胱氨酸积累并不是 胱氨酸病中观察到的所有缺陷的唯一原因。我们最近揭示了伴侣的一个有缺陷的机制—— 胱氨酸中毒介导的自噬（CMA）。 CMA 缺陷与人类疾病（包括肾脏疾病）直接相关 病理学和神经系统疾病。胱氨酸病的 CMA 缺陷是由错误定位和 唯一的溶酶体 CMA 受体 LAMP2A 的下调。 CMA 活性缺陷与高 胱氨酸病对细胞死亡的敏感性。重要的是，胱氨酸消耗疗法未能挽救该缺陷 支持其独立于溶酶体过载。我们的数据强调 CMA 损伤是一个重要因素 胱氨酸病的发病机制的贡献者，并强调需要新的治疗方法来补充胱氨酸 耗尽疗法。我们的研究计划旨在阐明导致的分子和细胞机制 胱氨酸病中 CMA 活性异常。我们还提出了利用小分子的转化方法 CMA 激活剂可改善胱氨酸中毒的细胞功能。我们的具体目标是： 目标 1：阐明 胱氨酸中毒中 LAMP2A 功能调节的分子基础。为此，我们将研究相互作用 CTNS 蛋白和 CMA 受体 LAMP2A 之间的关系，并阐明介导 LAMP2A 的机制 胱氨酸病中溶酶体膜的运输和不稳定。目标 2：确定分子基础 胱氨酸中毒中 CMA 活性的调节。我们将研究 CTNS 介导的调节机制 CMA 功能并将检验拯救 CMA 活性可改善近曲小管功能的假设 来自胱氨酸患者的细胞。目标 3：利用小分子 CMA 激活剂在体内改善肾功能 在胱氨酸小鼠中。我们将单独使用 CMA 激活剂或联合使用 CMA 激活剂来纠正胱氨酸病小鼠的细胞和肾功能。 与半胱胺组合。我们的研究非常重要，因为它旨在阐明分子 与破坏性人类病理学相关的机制，将有助于开发新的疗法 治疗胱氨酸病和其他人类疾病。