Mechanisms of ER-Protein Quality Control in Podocytes

足细胞内质网蛋白质量控制机制

基本信息

批准号：
10579572
负责人：
Ling Qi
金额：
$ 39.96万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-01 至 2023-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10579572
关键词：
Adult Affect Age Autophagocytosis Autophagosome Biogenesis Biology Cell Count Cell Death Cell Survival Cell physiology Child Complex Data Defect Degradation Pathway Disease Electrons Endoplasmic Reticulum Ensure Female Filtration Foot Process Growth Health Homeostasis Human Impairment In Vitro Integral Membrane Protein Investments Laboratories Link Longevity Mediating Microscopic Modeling Molecular Mus Nephrotic Syndrome Pathogenesis Pathologic Physiological Physiology Play Proteins Proteinuria Proteomics Quality Control Role Structure System Testing Therapeutic Work Yeasts autosome clinically relevant gain of function in vivo insight interest loss of function male misfolded protein mouse model mutant nephrin podocyte premature prevent protein aggregation protein complex protein degradation protein folding response slit diaphragm synergism

项目摘要

Mechanisms of ER Protein Quality Control in Podocytes SUMMARY My laboratory has a long-standing interest in protein folding and degradation within the endoplasmic reticulum (ER) by defining the physiological and pathological importance of mammalian ER quality-control machineries in vivo. ER-associated degradation (ERAD) is the principal protein quality-control mechanism responsible for targeting misfolded proteins in the ER for cytosolic proteasomal degradation. The SEL1L-HRD1 protein complex represents the most conserved branch of ERAD. We recently showed that mice with Sel1L deficiency in podocytes develop proteinuria at ~5 weeks of age and die prematurely with a median life span of ~14 weeks for both males and females (Yoshida et al. 2021 J CIin Invest). Electron microscopic analyses revealed foot process effacement and impaired slit diaphragm in the absence of Sel1L. Mechanistically, we showed that SEL1L-HRD1 ERAD in podocytes plays a critical role in the maturation of nascent nephrin in the ER, without affecting podocyte cell number and survival. In our recent work, our preliminary data suggested a possible crosstalk, or likely synergism, between ERAD and another key degradative pathway autophagy in podocytes. We propose to test the overarching hypothesis that the SEL1L-HRD1 ERAD protein complex plays a critical role in podocytes by coordinating the activation of autophagy, which ensures cellular homeostasis and filtration function. This model challenges/expands the current paradigm in ER biology by placing SEL1L-HRD1 ERAD at the center of cellular function in normal physiology and disease pathogenesis. Using various mouse models, we will accomplish the following Aims: (1) Demonstrate the pathophysiological importance of the crosstalk between SEL1L-HRD1 ERAD and autophagy in podocytes; (2) Determine how SEL1L-HRD1 ERAD controls autophagy activity in podocytes; and (3) Delineate the pathological importance and mechanism of ERAD and autophagy in the pathogenesis of nephrin disease mutants involved in nephrotic syndrome. This study will provide unprecedented insights into the crosstalk among key ER quality control machineries in podocytes, and shed new light on the therapeutic potential of targeting ER homeostasis in podocytes. RELEVANCE TO HUMAN HEALTH: Defects in podocytes and in the formation slit diaphragm, a specialized structure involving many transmembrane proteins, underlie nephrotic syndrome, affecting children and adults of all ages. While the ER quality control systems are presumably integrated to maintain ER homeostasis, the crosstalk between quality-control systems has not yet been investigated in vivo. This study will establish the pathophysiological significance of ERAD and the crosstalk between ERAD and autophagy in podocytes in health and diseases.

足细胞内质网蛋白质量控制机制概括我的实验室长期以来对内质网内的蛋白质折叠和降解感兴趣（ER）通过定义哺乳动物 ER 质量控制机制的生理和病理重要性体内。 ER 相关降解 (ERAD) 是主要的蛋白质质量控制机制，负责针对内质网中错误折叠的蛋白质进行胞质蛋白酶体降解。 SEL1L-HRD1 蛋白复合物代表 ERAD 最保守的分支。我们最近发现 Sel1L 缺陷的小鼠足细胞在约 5 周龄时出现蛋白尿并过早死亡，中位寿命约 14 周男性和女性（Yoshida et al. 2021 J CIin Invest）。电子显微镜分析揭示足部突起在没有 Sel1L 的情况下，会出现消失和狭缝隔膜受损的情况。从机制上讲，我们表明 SEL1L-HRD1 足细胞中的 ERAD 在 ER 中新生去氧肾上腺素的成熟中起着关键作用，而不影响足细胞细胞数量和存活率。在我们最近的工作中，我们的初步数据表明可能存在串扰，或者可能 ERAD 与足细胞中另一个关键降解途径自噬之间的协同作用。我们建议测试总体假设是 SEL1L-HRD1 ERAD 蛋白复合物通过以下方式在足细胞中发挥关键作用：协调自噬的激活，确保细胞稳态和过滤功能。这个型号通过将 SEL1L-HRD1 ERAD 置于细胞的中心，挑战/扩展了 ER 生物学的当前范式在正常生理和疾病发病机制中发挥作用。使用各种鼠标模型，我们将完成以下目标：(1) 证明 SEL1L-HRD1 之间串扰的病理生理学重要性足细胞中的 ERAD 和自噬； (2)确定SEL1L-HRD1 ERAD如何控制自噬活性足细胞； (3) 描述 ERAD 和自噬在细胞中的病理重要性和机制涉及肾病综合征的肾病蛋白疾病突变体的发病机制。这项研究将提供前所未有的深入了解足细胞中关键 ER 质量控制机制之间的串扰，并为解释针对足细胞内质网稳态的治疗潜力。与人类健康的相关性：足细胞和狭缝隔膜的形成缺陷，这是一种专门的涉及许多跨膜蛋白的结构，是肾病综合征的基础，影响儿童和成人所有年龄段。虽然 ER 质量控制系统大概是为了维持 ER 稳态而整合的，质量控制系统之间的串扰尚未在体内进行研究。这项研究将建立健康中 ERAD 的病理生理学意义以及 ERAD 与足细胞自噬之间的串扰和疾病。