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.

产品描述（由申请方提供）：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作用。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，并对靶组织发挥不同的生物学功能。脂联素多聚体是高度稳定的，并且不会自发地从一个物种相互转化为另一个物种。然而，目前尚不清楚不同脂联素种类的生物合成如何在细胞中调节。为了鉴定脂联素相互作用蛋白，我们以脂联素为诱饵，从人胎脑中筛选了一个酵母双杂交cDNA文库。这一筛选导致确定了一个 25 kDa蛋白，以前称为谷胱甘肽-S-转移酶（GST）-κ。GST-κ含有两个硫氧还蛋白结构域，并且C-末端硫氧还蛋白结构域与细菌二硫键-A（DsbA）氧化还原酶（一种参与革兰氏阴性菌周质中二硫键形成的酶）具有高度的结构和序列同源性。我们的初步研究表明，GST-κ和脂联素共定位于不同的细胞器结构和GST-κ与脂联素在体外和细胞中相互作用。此外，我们发现GST-κ在脂肪组织中高度表达，并且GST-κ的表达在肥胖小鼠和人类受试者中以及通过TNF 1a治疗而降低，并且由曲格列酮诱导。此外，我们发现通过RNAi抑制GST-κ显著且特异性地降低分化的3 T3-L1脂肪细胞中的脂联素水平和分泌。基于这些新的发现，我们推测GST-κ可能作为一种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。为了进一步验证这一假设，我们将：1）确定GST-κ是否调节3 T3-L1脂肪细胞中脂联素多聚体的组装和/或分泌; 2）阐明GST-κ调节脂联素多聚体组装和/或分泌的机制。 GST-κ调节脂联素多聚体多聚化和/或分泌;和3）产生脂肪组织特异性GST-κ敲除小鼠以确定GST-κ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，还将为胰岛素抵抗和2型糖尿病等代谢性疾病的新药物干预设计提供有价值的信息。公共卫生相关性：脂联素是一种脂肪组织来源的激素，具有抗糖尿病和抗炎作用。循环脂联素在细胞内发生多聚化，不同的寡聚体亚型发挥不同的生物学功能。该研究旨在阐明脂联素多聚化调节的生化和细胞机制，这将为胰岛素抵抗和2型糖尿病等代谢性疾病的新药物干预设计提供重要信息。