Adiporedoxin, a Novel Player in Adipokine Secretion

Adiporedoxin，脂肪因子分泌的新参与者

• 批准号: 8293640
• 负责人: PAUL F PILCH
• 金额: $ 35.59万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-16 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8293640
• 关键词: Active Sites; Acute; Address; Adipocytes; Adipose tissue; Adrenergic Agents; Affect; Area; Biology; Blood; Body Weight; Brain; Cell Line; Cell membrane; Cells; Cellular Stress; Complement; Cysteine; DNA Sequence Rearrangement; Data; Development; Diet; Disease; Dominant-Negative Mutation; Drug or chemical Tissue Distribution; Endoplasmic Reticulum; Energy Metabolism; Enzymes; Event; Family; Fatty Acids; Fatty acid glycerol esters; Gene Targeting; Goals; Health; Hormones; Human; Hydrogen Peroxide; Hypoxia; Immunoprecipitation; In Vitro; Infection; Insulin; Insulin Receptor; Insulin Resistance; Leptin; Lipids; Liver; Mass Spectrum Analysis; Mediating; Membrane; Membrane Proteins; Molecular; Molecular Chaperones; Mono-S; Mus; Muscle; Names; Obesity; Organ; Organism; Oxidation-Reduction; Physiological; Process; Production; Property; Proteins; Proteome; Quality Control; Regulation; Role; Stress; Structure; Substrate Interaction; Testing; Testis; Therapeutic; Thioredoxin; Tissues; Transfection; Tunicamycin; adiponectin; adipsin; adrenergic; blood glucose regulation; cell type; cytokine; diabetic; disulfide bond; endoplasmic reticulum stress; energy balance; feeding; insulin sensitivity; lipoprotein lipase; meetings; member; mutant; novel; peroxiredoxin; protein folding; protein function; research study; resistin; response; small hairpin RNA

DESCRIPTION (provided by applicant): The long-term goals of this project are to reveal mechanisms by which adipocytes function to regulate energy balance and metabolism in humans. Adipocytes secrete a variety of physiologically important proteins including the adipokines (adipose-derived cytokines) leptin and adiponectin. The assembly and secretion of these and other adipokines is initiated in the endoplasmic reticulum (E.R.) where various chaperones and redox-sensitive enzymes are involved in protein folding and disulfide bond formation. We recently discovered a novel membrane protein of the E.R. that is a member of the thioredoxin/peroxiredoxin family. We named it adiporedoxin (Arx) because it is expressed to a significant degree only in white and brown in adipocytes as well as in testes, and its function, like that of related proteins, is to assist in disulfide bond formation and protein folding. Our preliminary data show that by altering the expression of adiporedoxin, we can corresponding alter the levels of secreted adipsin (a complement-related adipokine) and adiponectin, an important adipokine whose levels correlate positively with insulin sensitivity. Moreover, over and under expression of adiporedoxin in cultured mouse adipocytes causes corresponding changes in the amount of the insulin receptor. What these three proteins have in common, aside for important physiological functions, is the need for multiple disulfide bonds in their tertiary and quaternary structure. Our preliminary data support the hypothesis that adiporedoxin may be a major regulator of adipocyte protein assembly and secretion. We will test this hypothesis in Aim1 where mechanistic properties of Arx related to protein assembly and secretion will be investigated in co-transfection experiments with adipokines. In Aim2 we will use adipocytes and various Arx constructs to determine how this protein functions in its physiological milieu in vitro We will interrogate the entire proteome, the secretome and the plasma membrane proteome of Arx over and under expressing fat cells. In Aim3 will determine the effects of endoplasmic stress and obesity on Arx function with regard to adipokines and other possible substrates.. Taken together, the proposed experimentation will reveal fundamental aspect of eukaryotic biology, the function of the endoplasmic reticulum in protein folding and disulfide bond assembly. This very important area of quality control for proteins secreted from adipocytes has been minimally investigated, and the topic has important consequences for human health and disease. If adipokine production is disrupted by changes in adiporedoxin expression, it is highly likely that long-term negative consequences for the organism will occur such as obesity and insulin resistance. By understanding the mechanism of Arx action, these consequences can be addressed by appropriate therapeutic strategies. PUBLIC HEALTH RELEVANCE: Adipocytes or fat cells produce a variety of hormone-like substance and release them into the blood, after which they act on tissues such as muscle and brain to regulate body weight and have anti-diabetic properties. It is the goal of this proposal to describe the molecular details by which these hormone-like substances are made and assembled in the fat cell because these cellular events determine circulating hormone levels, and in turn, the response of other tissues, which may include disease-causing abnormalities if their assembly is compromised.

描述（由申请人提供）：该项目的长期目标是揭示脂肪细胞调节人体能量平衡和新陈代谢的机制。脂肪细胞分泌多种生理上重要的蛋白质，包括脂肪因子（脂肪源性细胞因子）瘦素和脂联素。这些和其他脂肪因子的组装和分泌在内质网 (E.R.) 中启动，其中各种伴侣和氧化还原敏感酶参与蛋白质折叠和二硫键形成。我们最近发现了一种新型的内质网膜蛋白，它是硫氧还蛋白/过氧化氧还蛋白家族的成员。我们将其命名为脂孔还蛋白（Arx），因为它在脂肪细胞和睾丸中仅以白色和棕色表达，其功能与相关蛋白质一样，是协助二硫键形成和蛋白质折叠。我们的初步数据表明，通过改变脂孔还蛋白的表达，我们可以相应地改变分泌的脂肪素（一种补体相关脂肪因子）和脂联素的水平，脂联素是一种重要的脂肪因子，其水平与胰岛素敏感性呈正相关。此外，培养的小鼠脂肪细胞中脂孔还蛋白的过度和不足表达会引起胰岛素受体数量的相应变化。除了重要的生理功能外，这三种蛋白质的共同点是其三级和四级结构中需要多个二硫键。我们的初步数据支持这样的假设：脂孔还蛋白可能是脂肪细胞蛋白质组装和分泌的主要调节剂。我们将在 Aim1 中测试这一假设，其中将在与脂肪因子的共转染实验中研究与蛋白质组装和分泌相关的 Arx 的机制特性。在 Aim2 中，我们将使用脂肪细胞和各种 Arx 构建体来确定该蛋白质如何在其体外生理环境中发挥作用。我们将询问 Arx 过度表达和表达不足的脂肪细胞的整个蛋白质组、分泌组和质膜蛋白质组。在 Aim3 中，将确定内质应激和肥胖对脂肪因子和其他可能底物方面的 Arx 功能的影响。总之，拟议的实验将揭示真核生物学的基本方面，即内质网在蛋白质折叠和二硫键组装中的功能。对脂肪细胞分泌的蛋白质的这一非常重要的质量控制领域的研究很少，该主题对人类健康和疾病具有重要影响。如果脂肪因子的产生因脂孔还蛋白表达的变化而受到干扰，则很可能会对生物体产生长期的负面后果，例如肥胖和胰岛素抵抗。通过了解 Arx 的作用机制，可以通过适当的治疗策略来解决这些后果。 公共健康相关性：脂肪细胞或脂肪细胞产生多种激素样物质并将其释放到血液中，然后作用于肌肉和大脑等组织，调节体重并具有抗糖尿病特性。该提案的目标是 描述了这些类激素物质在脂肪细胞中制造和组装的分子细节，因为这些细胞事件决定了循环激素水平，进而决定了其他组织的反应，如果它们的组装受到损害，可能包括导致疾病的异常。