The Function of Prohibitin / Annexin 2 Interaction in White Adipose Tissue

白色脂肪组织中抑制素/膜联蛋白 2 相互作用的功能

• 批准号: 8080802
• 负责人: Mikhail G Kolonin
• 金额: $ 32.18万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8080802
• 关键词: ANXA2 gene; Adipocytes; Adipose tissue; Adult; Annexins; Binding; Binding Proteins; Biology; Blood Vessels; Cardiovascular Diseases; Cell Culture Techniques; Cell Differentiation process; Cell membrane; Cell surface; Cells; Clinical Trials; Complex; Cytotoxic agent; Data; Development; Diet; Dominant-Negative Mutation; Endocytosis; Endothelial Cells; Endothelium; Enterochromaffin Cells; Fatty Acids; Glucose; Homeostasis; Hyperplasia; Hypertrophy; Impairment; Individual; Knockout Mice; Lipids; Lipolysis; Maintenance; Malignant Neoplasms; Measures; Mediating; Medical; Membrane Microdomains; Modeling; Mus; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Peptides; Physiological Processes; Play; Population; Process; Property; Protein Binding; Proteins; Role; Staging; Stem cells; Stromal Cells; Surface; Testing; Therapeutic; Tissue Expansion; Triglycerides; Vascularization; Wild Type Mouse; Work; angiogenesis; base; design; fatty acid oxidation; follow-up; glucose uptake; lipid biosynthesis; migration; mutant; novel; prohibitin; prospective; protein complex; public health relevance; receptor; socioeconomics; stromal progenitor; uptake

DESCRIPTION (provided by applicant): Obesity results from excessive expansion of white adipose tissue (WAT). We previously identified prohibitin (Phb) as a protein present on the endothelial cell (EC) surface selectively in WAT and have used a peptide CKGGRAKDC, which binds to Phb and undergoes Phb-mediated endocytosis, to direct a cytotoxic agent to mouse WAT as an experimental approach to obesity reversal. In order to better establish Phb as a prospective obesity therapy target, we have begun to characterize its currently undefined function in WAT. We identified annexin A2, also known as annexin II (Anx2), as a Phb-binding protein mimicked by the CKGGRAKDC peptide. While Anx2 has been previously shown to have a pro-angiogenic function, suggesting a role for Phb / Anx2 interaction in WAT endothelium, the role of Anx2 in adipose biology has not been explored. Our preliminary studies revealed Phb / Anx2 complex in cell membrane lipid rafts not only in WAT endothelium but also in adipocytes. Moreover, we discovered that Anx2 function is required during adipogenesis. Based on these observations, we hypothesize that in EC and in adipocytes Phb and Anx2 form a receptor complex that plays an important role in WAT development and homeostasis. To test our hypothesis, we will dissect the adipogenic and angiogenic functions of Anx2 and Phb in WAT based on mouse and cell culture models, as well as on our preliminary data identifying Phb / Anx2 interaction domains, in the following Specific Aims. (1) We will investigate the role of Anx2 in WAT development. By comparing individual WAT depots from Anx2-deficient and wild-type mice at different stages of development and upon diet-induced obesity induction, we will determine the importance of Anx2 for adipogenesis and WAT angiogenesis by assessing WAT expansion and adipocyte properties, as well as by analyzing WAT vascularization and the representation of WAT cell populations. (2) We will explore the function of Phb / Anx2 interaction in adipogenesis and WAT angiogenesis. In Sub-Aim 2A, we will determine why lipid droplet accumulation is impaired in adipocytes upon perturbation of Anx2 function. By using differentiating adipocytes either completely lacking Anx2 or designed to be deficient in Phb / Anx2 binding, we will assess changes in expression and localization of proteins marking adipogenesis and will measure glucose and fatty acid uptake, as well as lipolysis. In Sub-Aim 2B, we will test the role of Phb / Anx2 interaction in WAT vasculature by assessing proliferation, migration, and vasculature formation capacity of EC either completely lacking Anx2 or designed to be deficient in Phb / Anx2 binding. As a result, we will establish the role of the cell surface interaction between Phb and Anx2 in WAT. This will contribute to our understanding of the mechanisms governing WAT tissue expansion and provide valuable information on the biology of this protein complex potentially useful as a target of anti-obesity therapeutics. PUBLIC HEALTH RELEVANCE: Obesity is positively associated with cardiovascular disease, type 2 diabetes, and cancer, thus representing a socioeconomic and medical problem of escalating concern. Our study will contribute to the understanding of mechanisms that control adipose cell differentiation and blood vessel formation during the expansion of white adipose tissue responsible for obesity. The molecular interaction between prohibitin and annexin 2 uncovered by our work is a potential target for anti-obesity therapy, and this study is a next step toward prospective clinical trials.

描述（由申请人提供）：肥胖是由于白色脂肪组织（WAT）的过度膨胀而导致的。我们先前以前在WAT中选择性地鉴定出存在于内皮细胞（EC）表面上的蛋白质，并使用了肽CKGGRAKDC，该肽与PHB结合并进行PHB介导的内吞作用，以将细胞毒素引导到小鼠WAT作为obesity obesity逆转的实验方法。为了更好地将PHB作为前瞻性肥胖疗法靶标建立，我们已经开始表征其当前在WAT中不确定的功能。我们确定膜联蛋白A2，也称为膜联蛋白II（ANX2），是由CKGGRAKDC肽模仿的PHB结合蛋白。虽然先前已证明Anx2具有促血管生成功能，这表明pHB / ANX2在WAT内皮中的相互作用起作用，但尚未探索Anx2在脂肪生物学中的作用。我们的初步研究揭示了细胞膜脂质筏中的PHB / ANX2复合物不仅在WAT内皮中，而且在脂肪细胞中。此外，我们发现在脂肪形成过程中需要Anx2功能。基于这些观察结果，我们假设在EC和脂肪细胞中，PHB和Anx2在WAT发育和稳态中起着重要作用。为了检验我们的假设，我们将根据小鼠和细胞培养模型以及我们的初步数据识别PHB / ANX2相互作用域的初步数据，在WAT中剖析ANX2和PHB的掺杂和血管生成功能。 （1）我们将研究Anx2在WAT开发中的作用。通过比较在发育的不同阶段和饮食引起的肥胖诱导阶段的Anx2缺陷和野生型小鼠中的单个WAT仓库，我们将通过评估Anx2对脂肪生成和WAT血管生成的重要性，通过评估WAT膨胀和脂肪细胞的特性，以及分析WAT WAT血管化以及分析WAT Cell Cell群的重要性。 （2）我们将探讨PHB / ANX2相互作用在脂肪生成和WAT血管生成中的功能。在Sub-aim 2a中，我们将确定为什么在Anx2功能扰动时脂肪细胞中脂质液滴积累会受到损害。通过使用分化的脂肪细胞完全缺乏Anx2或设计为缺乏PHB / Anx2结合的脂肪细胞，我们将评估标记脂肪形成的蛋白质表达和定位的变化，并将测量葡萄糖和脂肪酸的摄取以及脂肪分解。在Sub-aim 2b中，我们将通过评估EC的增殖，迁移和脉管形成能力完全缺乏ANX2或设计为缺乏PHB / ANX2结合的eC的增殖，迁移和脉管形成能力，来测试PHB / ANX2相互作用在WAT脉管系统中的作用。结果，我们将在WAT中确定PHB和Anx2之间细胞表面相互作用的作用。这将有助于我们理解管理WAT组织扩展的机制，并提供有关该蛋白质复合物的生物学的宝贵信息，这可能是抗肥胖疗法的靶标。 公共卫生相关性：肥胖与心血管疾病，2型糖尿病和癌症呈正相关，因此代表了社会经济和医学问题的升级问题。我们的研究将有助于理解控制脂肪细胞分化和血管形成的机制，这是在负责肥胖的白色脂肪组织的扩张。我们工作发现的禁止素和膜联蛋白2之间的分子相互作用是抗肥胖治疗的潜在靶标，这项研究是迈向前瞻性临床试验的下一步。