Elucidating novel molecular mechanisms of irisin-mediated effects via integrin

通过整合素阐明鸢尾素介导作用的新分子机制

• 批准号: 10617263
• 负责人: Mu A
• 金额: $ 7.18万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10617263
• 关键词: Adipocytes; Adipose tissue; Affect; Affinity; Affinity Chromatography; Amino Acids; Animals; Antibodies; Binding; Biochemical; Biochemistry; Biological; Biophysics; Blood; Bone remodeling; Brain; Bypass; Cardiovascular Diseases; Cardiovascular system; Cell Culture Techniques; Cell surface; Cells; Cellular Metabolic Process; Cellular biology; Cognitive deficits; Complex; Cultured Cells; Data; Degenerative Disorder; Development; Disease; Disease Progression; Equilibrium; Exercise; Exhibits; Fatty acid glycerol esters; Fibronectins; Fluorescence Microscopy; Functional disorder; Half-Life; Heart; Heat-Shock Response; Hormones; Human; Individual; Integrin Binding; Integrin alphaV; Integrins; Life Style; Ligand Binding; Ligands; Liver; Malignant Neoplasms; Mammalian Cell; Maps; Measures; Mediating; Membrane Proteins; Mental disorders; Metabolic Diseases; Metabolism; Molecular; Morbid Obesity; Mus; Muscle; Muscle Cells; Muscle Fibers; Muslim religion; N-terminal; Nature; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Organ; PPAR gamma; Pathogenesis; Pathway interactions; Pattern; Persons; Pharmaceutical Preparations; Physical activity; Physiology; Plasma; Proteins; Publishing; RGD (sequence); Recombinant Proteins; Recombinants; Research; Resources; Role; Scientist; Signal Transduction; Site; Skeletal Muscle; Structure; Symptoms; Technology; Testing; Therapeutic; Tissues; Training; Transcription Coactivator; Work; age related; biophysical properties; bone; cofactor; disability; endurance exercise; glycosylation; improved; in vivo; molecular modeling; mutant; myogenesis; neuropathology; novel; obese patients; physical inactivity; polypeptide; prevent; protein purification; receptor; receptor binding; sedentary; sedentary lifestyle; subcutaneous

PROJECT SUMMARY: Exercise benefits the body in many ways. The functions of skeletal muscle, brain, liver, bone, adipose tissue and heart all gain from various types of physical activity and training. People suffering from disabilities, morbid obesity, or age-related diseases, are usually physically inactive, which exacerbates their symptoms and leads to development of other types of diseases, such as type 2 diabetes mellitus, cardiovascular diseases, and some forms of cancers. Scientific explorations of exercise have become more molecular, focusing on the pathways and molecules that mediate these benefits. Irisin has been identified as an exercise-induced hormone that embodies many adaptations to exercise in a variety of tissues/organs, including “browning” of subcutaneous adipose tissue, bone remodeling, improving cognitive deficits and neuropathology, and promoting myogenesis of skeletal muscles. In bone and fat, the effects of irisin are mediated via αv integrins, with αvβ5 identified as the major receptor. However, my biochemical and biophysical characterization of direct interaction between irisin and αvβ5 suggested extremely weak binding, while the concentrations of irisin that induce detectable amount of irisin-mediated effects in the body and in the cultured cells are really low, indicating a very high irisin/receptor binding affinity. This paradox could be explained by the existence of an additional factor that facilitates irisin/integrin interaction and irisin-mediated integrin activation. My preliminary data suggested that an exercise-induced circulating protein Hsp90α binds to integrin αvβ5, and functions as a cofactor to mediate the binding of irisin to integrin and irisin-induced integrin signaling. Irisin is different from many integrin ligands in that irisin is small, heavily glycosylated, and lacks the well-identified integrin binding motif, indicating a non-canonical ways of ligand binding to integrins. Biophysical and biochemical approaches will be used to characterize the complexes formed by irisin (WT and glycosylation mutants), αvβ5 and Hsp90α. The molecular model will be firstly tested in HEK293T cells ectopically expressing αv and β5, and muscle and fat cells, using molecular approaches and fluorescence microscopy. The effects of Hsp90α will be further evaluated in mice. Taken together, these studies will advance our understanding of irisin-mediated (or hormone-mediated, in general) integrin signaling, which will assist drug and antibody development to treat patients with obesity, aged-related diseases and neuro- or muscular degenerative disorders. The proposed project represents a great balance between biochemistry/biophysics as well as cell biology, in which I was trained during my Ph.D, and cell metabolism and animal physiology, which are the primary technologies employed by the Spiegelman lab. The resources provided by Bruce’s networks, DFCI and HMS, tremendously facilitated my research, and will support me to become an independent scientist.

项目概要： 锻炼对身体有很多好处。骨骼肌、脑、肝、骨、脂肪组织的功能 和心脏都从各种类型的身体活动和训练中获益。患有残疾、病态的人 肥胖或与年龄相关的疾病通常缺乏身体活动，这会加剧症状并导致 其他类型疾病的发展，例如2型糖尿病、心血管疾病和一些 癌症的形式。对运动的科学探索已变得更加分子化，重点关注路径 以及介导这些益处的分子。鸢尾素已被确定为一种运动诱发的激素， 体现了多种组织/器官对运动的多种适应，包括皮下组织的“褐变” 脂肪组织、骨重塑、改善认知缺陷和神经病理学、促进肌生成 骨骼肌。 在骨骼和脂肪中，鸢尾素的作用是通过 αv 整合素介导的，其中 αvβ5 被确定为主要受体。 然而，我对鸢尾素和 αvβ5 之间直接相互作用的生化和生物物理表征 表明结合极弱，而诱导可检测量的鸢尾素浓度 体内和培养细胞中鸢尾素介导的作用非常低，表明鸢尾素/受体非常高 结合亲和力。这个悖论可以用另一个因素的存在来解释，这个因素有利于 鸢尾素/整合素相互作用和鸢尾素介导的整合素激活。我的初步数据表明 运动诱导的循环蛋白 Hsp90α 与整合素 αvβ5 结合，并作为辅助因子介导 鸢尾素与整合素的结合以及鸢尾素诱导的整合素信号传导。鸢尾素与许多整合素配体不同 鸢尾素很小，糖基化程度很高，并且缺乏明确的整合素结合基序，这表明 配体与整合素结合的非规范方式。 将使用生物物理和生化方法来表征鸢尾素（WT 和 糖基化突变体）、αvβ5 和 Hsp90α。该分子模型将首先在HEK293T细胞中进行测试 使用分子方法和荧光异位表达 αv 和 β5 以及肌肉和脂肪细胞 显微镜。 Hsp90α 的作用将在小鼠中进一步评估。总而言之，这些研究将取得进展 我们对鸢尾素介导（或一般来说激素介导）整合素信号传导的理解，这将有助于药物 以及抗体开发，以治疗肥胖症、老年相关疾病以及神经或肌肉疾病患者 退行性疾病。 拟议的项目代表了生物化学/生物物理学以及细胞生物学之间的巨大平衡， 我在攻读博士学位期间接受的培训，以及细胞代谢和动物生理学，这是主要的 斯皮格曼实验室采用的技术。 Bruce的网络、DFCI和HMS提供的资源， 极大地促进了我的研究，并将支持我成为一名独立科学家。