Regulation and Function of Adiponectin Oligomerization

脂联素寡聚化的调控和功能

• 批准号: 7997090
• 负责人: FENG LIU
• 金额: $ 9.9万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-14 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7997090
• 关键词: Adipocytes; Adipose tissue; Affect; Agonist; Anti-Inflammatory Agents; Anti-inflammatory; Antiatherogenic; Biochemical; Biogenesis; Biological Process; Blood Circulation; Brain; C-terminal; Cells; Cultured Cells; Defect; Development; Diabetes Mellitus; Dimerization; Disulfides; Enzymes; Family; Figs - dietary; Genes; Glutathione S-Transferase; Gram-Negative Bacteria; Hormones; Human; Impairment; In Vitro; Inflammatory; Insulin Resistance; Intervention; Knockout Mice; Lead; Light; Metabolic Diseases; Molecular; Molecular Weight; Mus; Names; Non-Insulin-Dependent Diabetes Mellitus; Obese Mice; Organelles; Oxidoreductase; Peroxisome Proliferator-Activated Receptors; Pharmaceutical Preparations; Physiological; Plasma; Play; Protein Disulfide Isomerase; Protein Isoforms; Proteins; RNA Interference; Regulation; Research; Role; Screening procedure; Sequence Homology; Serine; Signal Pathway; Specificity; Structure; TNF gene; Testing; Thioredoxin; Tissues; Yeasts; adipokines; adiponectin; base; cDNA Library; cytokine; design; diabetic; disulfide bond; fetal; human subject; in vitro activity; in vivo; insulin sensitizing drugs; insulin signaling; interest; member; novel; novel therapeutics; obesity treatment; periplasm; public health relevance; response; troglitazone; yeast two hybrid system

DESCRIPTION (provided by applicant): Adiponectin is an adipose tissue-derived hormone with anti-diabetic, anti-atherogenic, and anti-inflammatory functions. Circulating adiponectin exists as trimer, hexamer, and high molecular weight species which activate divergent signaling pathways and exert distinct biological functions on their target tissues. Adiponectin multimers are highly stable and do not interconvert from one species to another spontaneously. However, it is currently unknown how the biogenesis of the different adiponectin species is regulated in cells. To identify adiponectin interacting proteins involved in regulating adiponectin function, we screened a yeast two-hybrid cDNA library derived from human fetal brain, using adiponectin as bait. This screening led to the identification of a 25 kDa protein, previously named glutathione-S-transferase (GST)-kappa. GST-kappa contains two thioredoxin domains and the C-terminal thioredoxin domain shares high structural and sequence homology to bacterial disulfide-bond-A (DsbA) oxidoreductase, an enzyme involved in disulfide bond formation in the periplasm of Gram-negative bacteria. Our preliminary studies showed that GST-kappa and adiponectin are co-localized in distinct cellular organelle structures and GST-kappa interacts with adiponectin in vitro and in cells. In addition, we found that GST-kappa is highly expressed in adipose tissue and the expression of GST-kappa is reduced in obese mice and human subjects and by TNF1a-treatment, and is induced by troglitazone. Furthermore, we found that suppression of GST-kappa by RNAi markedly and specifically reduced adiponectin levels and secretion in differentiated 3T3-L1 adipocytes. Based on these novel findings, we hypothesize that GST-kappa may function as a protein disulfide isomerase and play an important role in regulating adiponectin multimerization and secretion. To further test this hypothesis, we will: 1) determine whether GST-kappa regulates adiponectin multimeric assembly and/or secretion in 3T3-L1 adipocytes; 2) elucidate the mechanism by which GST-kappa regulates adiponectin multimeric multimerization and/or secretion; and 3) generate adipose tissue-specific GST-kappa knockout mice to determine the physiological roles of GST-kappa in vivo. Results from these studies will not only shed light on our understanding of the mechanism regulating adiponectin multimerization and secretion, but will also provide valuable information on the design of new pharmacological interventions for metabolic diseases such as insulin resistance and type 2 diabetes. PUBLIC HEALTH RELEVANCE: Adiponectin is an adipose tissue-derived hormone with anti-diabetic and anti- inflammatory functions. Circulating adiponectin undergoes multimerization in cells and different oligomer isoforms exert distinct biological functions. The proposed study seeks to elucidate the biochemical and cellular mechanisms by which adiponectin multimerization is regulated, which will provide important information on the design of new pharmacological interventions for metabolic diseases such as insulin resistance and type 2 diabetes.

描述（申请人提供）：脂联素是一种脂肪组织来源的激素，具有抗糖尿病、抗动脉粥样硬化和抗炎功能。循环脂联素以三聚体、六聚体和高分子量形式存在，它们激活不同的信号传导途径并在其靶组织上发挥不同的生物学功能。脂联素多聚体高度稳定，不会自发地从一种物质相互转化为另一种物质。然而，目前尚不清楚不同脂联素种类的生物合成在细胞中是如何调节的。为了鉴定参与调节脂联素功能的脂联素相互作用蛋白，我们以脂联素为诱饵，筛选了源自人胎脑的酵母双杂交 cDNA 文库。此次筛查确定了 25 kDa 蛋白质，以前称为谷胱甘肽-S-转移酶 (GST)-kappa。 GST-kappa 包含两个硫氧还蛋白结构域，C 端硫氧还蛋白结构域与细菌二硫键-A (DsbA) 氧化还原酶具有高度的结构和序列同源性，细菌二硫键-A (DsbA) 氧化还原酶是一种参与革兰氏阴性细菌周质中二硫键形成的酶。我们的初步研究表明，GST-kappa 和脂联素共定位于不同的细胞器结构中，并且 GST-kappa 在体外和细胞内与脂联素相互作用。此外，我们发现GST-kappa在脂肪组织中高表达，并且GST-kappa的表达在肥胖小鼠和人类受试者中以及通过TNF1a治疗而降低，并且由曲格列酮诱导。此外，我们发现，RNAi 抑制 GST-kappa 显着且特异性地降低了分化的 3T3-L1 脂肪细胞中的脂联素水平和分泌。基于这些新发现，我们假设 GST-kappa 可能作为蛋白质二硫键异构酶发挥作用，并在调节脂联素多聚化和分泌中发挥重要作用。为了进一步检验这一假设，我们将： 1) 确定 GST-kappa 是否调节 3T3-L1 脂肪细胞中脂联素多聚体的组装和/或分泌； 2）阐明其机制 GST-kappa 调节脂联素多聚体多聚化和/或分泌； 3) 生成脂肪组织特异性 GST-kappa 敲除小鼠，以确定 GST-kappa 在体内的生理作用。这些研究的结果不仅有助于我们了解脂联素多聚化和分泌的调节机制，还将为设计针对胰岛素抵抗和2型糖尿病等代谢性疾病的新药理学干预措施提供有价值的信息。公众健康相关性：脂联素是一种脂肪组织来源的激素，具有抗糖尿病和抗炎功能。循环脂联素在细胞中发生多聚化，不同的寡聚物亚型发挥不同的生物学功能。拟议的研究旨在阐明脂联素多聚化调节的生化和细胞机制，这将为设计针对胰岛素抵抗和2型糖尿病等代谢性疾病的新药理学干预措施提供重要信息。