Redox Triggering of Glomerular NALP3 Inflammasomes in Hyperhomocysteinemia

高同型半胱氨酸血症中肾小球 NALP3 炎症小体的氧化还原触发

• 批准号: 8397308
• 负责人: Justine M Abais-Battad
• 金额: $ 3.39万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-10 至 2014-08-09
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8397308
• 关键词: Abbreviations; Acetaminophen; Adaptor Signaling Protein; Age; Aging; Apoptosis; Applications Grants; Cardiovascular Diseases; Cardiovascular system; Caspase-1; Cell membrane; Cells; Chronic; Diabetes Mellitus; Diet; Elderly; Electron Spin Resonance Spectroscopy; End stage renal failure; Folate; Functional disorder; Genes; Genetic; Goals; Gout; Hepatotoxicity; Homocysteine; Homocystine; Hyperhomocysteinemia; Immune System Diseases; Immune system; Impaired cognition; In Vitro; Inflammation; Inflammatory; Inflammatory Response; Injury; Interleukins; Kidney; Knock-out; Knockout Mice; Laboratories; Lead; Link; Mediating; Membrane; Metabolic Diseases; Modeling; Molecular Sieve Chromatography; Multienzyme Complexes; Multiprotein Complexes; Mus; NADPH Oxidase; Oxidation-Reduction; Pathology; Patients; Phase; Plasma; Play; Prevention; Proteins; Reactive Oxygen Species; Recruitment Activity; Renal function; Reporting; Research Proposals; Risk Factors; Role; Sclerosis; Signal Transduction; Silicosis; Superoxides; T-Lymphocyte; Testing; Work; age related; cytokine; extracellular; glomerulosclerosis; in vivo; macrophage; new therapeutic target; novel; overexpression; podocyte; protein complex; receptor; senescence; sex; therapeutic target

DESCRIPTION (provided by applicant): The overall goal of this proposal is to clarify the mechanisms underlying end-stage renal disease that occurs as a result from aging and hyperhomocysteinemia (hHcys). While there are many factors contributing to elevated plasma homocysteine (Hcys) such as sex, genetics, and kidney function, age itself is a major contributor, where upwards of 30% of the elderly suffer from hHcys. We have most recently demonstrated the importance of inflammasome activation in Hcys-induced glomerular damage; however, the precise mechanisms mediating this effect remain unknown. The inflammasome, a novel multiprotein complex, has been shown to play an essential role in the early initiation of the innate immune system. Aside from immune diseases, activation of the inflammasome has recently been linked to non-immune, metabolic diseases such as diabetes, gout, silicosis, and acetaminophen-induced liver toxicity. This grant proposal hypothesizes that elevated extracellular Hcys concentrations activate NADPH oxidase (Nox) to produce reactive oxygen species (ROS) and thereby activate NALP3 inflammasomes in podocytes and increase the downstream recruitment of inflammatory cells in glomeruli, resulting in podocyte injury, local inflammation and ultimately glomerular sclerosis. To test this hypothesis, three specific aims are proposed. Specific Aim 1 will determine whether the in vitro formation and activation of NALP3 inflammasomes by Hcys in mouse podocytes are associated with Nox-mediated redox signaling and will seek to explore the mechanisms mediating the precise action of Nox-derived ROS on inflammasome activation. Specific Aim 2 will attempt to test whether in vivo hHcys-induced activation of NALP3 inflammasomes and associated glomerular injury are blocked by selective inhibition of local Nox activity and expression or by knocking out the gp91phox gene in mice. Specific Aim 3 will determine whether in vivo pharmacological activation of Nox and overexpression of gp91phox gene enhance inflammasome formation in glomeruli of hyperhomocysteinemic mice and to observe whether gene rescuing in gp91phox knockout mice restores hHcys-induced activation of podocyte inflammasomes. This proposal will be the first to examine the triggering role of Nox-mediated redox signaling in inflammasome activation and the first to link both Nox and the inflammasome to the early initiating mechanisms leading to glomerular damage induced by Hcys. Results from these proposed studies may lead to the discovery of new therapeutic targets for the prevention and treatment of glomerular damage and the eventual end-stage renal disease that occurs in patients with hHcys, especially in the elderly. PUBLIC HEALTH RELEVANCE: Hyperhomocysteinemia (hHcys) is a risk factor known to majorly contribute to aging and many of its accompanied ailments including compromised kidney function, cardiovascular disease, cognitive decline and impaired mobility. This proposal seeks to understand how hHcys causes renal glomerular injury, and we believe that in an NADPH oxidase-mediated fashion, a new protein complex termed the inflammasome triggers glomerular injury during hHcys. It is our hope that our proposed studies may discover new and very early phase therapeutic targets for the prevention of age-related glomerular injury induced by hHcys.

描述（由申请方提供）：本提案的总体目标是阐明衰老和高同型半胱氨酸血症（hHcys）导致的终末期肾病的潜在机制。虽然有许多因素导致血浆同型半胱氨酸（HCys）升高，如性别，遗传和肾功能，但年龄本身是一个主要因素，其中超过30%的老年人患有HCys。我们最近已经证明了炎症小体激活在Hcy诱导的肾小球损伤中的重要性，然而，介导这种作用的确切机制仍然未知。炎性小体是一种新型的多蛋白复合物，已被证明在炎症的早期启动中起重要作用。 先天免疫系统除了免疫性疾病之外，炎性小体的激活最近已与非免疫性代谢性疾病如糖尿病、痛风、硅肺和对乙酰氨基酚诱导的肝毒性相关联。该资助提案假设升高的细胞外Hcys浓度激活NADPH氧化酶（Nox）以产生活性氧（ROS），从而激活足细胞中的NALP3炎性体并增加肾小球中炎性细胞的下游募集，导致足细胞损伤、局部炎症和最终肾小球硬化。为了检验这一假设，提出了三个具体目标。具体目标1将确定小鼠足细胞中Hcys对NALP 3炎性小体的体外形成和活化是否与Nox介导的氧化还原信号传导相关，并将寻求探索介导Nox衍生的ROS对炎性小体活化的精确作用的机制。具体目标2将尝试测试是否通过选择性抑制局部Nox活性和表达或通过敲除小鼠中的gp91phox基因来阻断体内hHcys诱导的NALP 3炎性体活化和相关肾小球损伤。具体目标3将确定体内Nox的药理学激活和gp91phox基因的过表达是否增强高同型半胱氨酸血症小鼠肾小球中的炎性小体形成，并观察gp91phox敲除小鼠中的基因拯救是否恢复hHcys诱导的足细胞炎性小体激活。这一建议将是第一个检查的触发作用的Nox介导的氧化还原信号在炎症体激活和第一个连接的Nox和炎症体的早期启动机制，导致肾小球损伤的半胱氨酸诱导。从这些拟议的研究结果可能会导致发现新的治疗靶点，用于预防和治疗肾小球损伤和最终的终末期肾病，发生在hHcys患者，特别是老年人。 公共卫生相关性：高同型半胱氨酸血症（hHcys）是已知主要导致衰老及其许多伴随疾病的风险因素，包括肾功能受损、心血管疾病、认知能力下降和活动能力受损。该建议旨在了解hHcys如何引起肾小球损伤，我们认为在NADPH氧化酶介导的方式中，一种称为炎性体的新蛋白复合物在hHcys期间触发肾小球损伤。我们希望我们提出的研究可能会发现新的和非常早期的治疗靶点，用于预防由hHcys诱导的年龄相关性肾小球损伤。