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: 8282866
• 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/8282866
• 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（由申请方提供）：肥胖是由白色脂肪组织（WAT）过度扩张引起的。我们之前在WAT中鉴定出抑制素（Phb）是选择性存在于内皮细胞（EC）表面的蛋白质，并使用与Phb结合并经历Phb介导的内吞作用的肽CKGGRAKDC将细胞毒性剂引导至小鼠WAT作为肥胖逆转的实验方法。为了更好地建立Phb作为一个前瞻性的肥胖治疗目标，我们已经开始表征其目前未定义的功能在WAT。我们鉴定了膜联蛋白A2，也称为膜联蛋白II（Anx 2），作为由CKGGRAKDC肽模拟的Phb结合蛋白。虽然Anx 2先前已被证明具有促血管生成功能，表明Phb /Anx 2相互作用在WAT内皮中的作用，但尚未探索Anx 2在脂肪生物学中的作用。我们的初步研究表明，Phb /Anx 2复合物不仅在WAT内皮细胞，而且在脂肪细胞膜脂筏。此外，我们发现Anx 2功能在脂肪形成过程中是必需的。基于这些观察结果，我们假设在EC和脂肪细胞中Phb和Anx 2形成受体复合物，在WAT的发展和稳态中起着重要作用。为了验证我们的假设，我们将在以下具体目标中，基于小鼠和细胞培养模型以及我们鉴定Phb /Anx 2相互作用结构域的初步数据，剖析Anx 2和Phb在WAT中的脂肪形成和血管生成功能。(1)我们将研究Anx 2在WAT开发中的作用。通过比较来自不同发育阶段的Anx 2缺陷型小鼠和野生型小鼠的个体WAT库以及饮食诱导的肥胖诱导，我们将通过评估WAT扩增和脂肪细胞特性以及通过分析WAT血管化和WAT细胞群的代表性来确定Anx 2对脂肪形成和WAT血管生成的重要性。(2)我们将探讨Phb /Anx 2相互作用在脂肪形成和WAT血管生成中的作用。在子目标2A中，我们将确定Anx 2功能扰动后脂肪细胞中脂滴蓄积受损的原因。通过使用完全缺乏Anx 2或设计为Phb /Anx 2结合缺陷的分化脂肪细胞，我们将评估标记脂肪形成的蛋白质的表达和定位的变化，并将测量葡萄糖和脂肪酸摄取以及脂解。在子目标2B中，我们将通过评估完全缺乏Anx 2或设计为缺乏Phb /Anx 2结合的EC的增殖、迁移和血管形成能力来测试Phb/Anx 2相互作用在WAT血管中的作用。因此，我们将建立Phb和Anx 2在WAT中的细胞表面相互作用的作用。这将有助于我们理解WAT组织扩张的机制，并提供有价值的信息，这种蛋白质复合物的生物学可能作为抗肥胖治疗的目标。 公共卫生相关性：肥胖与心血管疾病、2型糖尿病和癌症正相关，因此代表了日益关注的社会经济和医学问题。我们的研究将有助于了解在负责肥胖的白色脂肪组织扩张过程中控制脂肪细胞分化和血管形成的机制。我们的工作揭示了prohibitin和annexin 2之间的分子相互作用是抗肥胖治疗的潜在靶点，这项研究是前瞻性临床试验的下一步。