Role of mechanically activated Src/mTORC2 signaling on cytoskeletal adaptation

机械激活的 Src/mTORC2 信号对细胞骨架适应的作用

• 批准号: 8457722
• 负责人: William Roy Thompson
• 金额: $ 5.39万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8457722
• 关键词: Actins; Address; Adhesions; Adipocytes; Adolescent; Affect; Aging; American; Biological Assay; Cardiovascular Diseases; Cell Lineage; Chemicals; Child; Cytoskeletal Modeling; Cytoskeleton; Data; Diabetes Mellitus; Elderly; Environment; Estrogens; Event; Exercise; Family; Fatty acid glycerol esters; Focal Adhesion Kinase 1; Focal Adhesions; Fostering; Fracture; Growth; Health; In Vitro; Intervention; Lead; Life Style; Link; Malignant Neoplasms; Marrow; Measures; Mechanics; Mentors; Mesenchymal Stem Cells; Multiprotein Complexes; Obesity; Osteogenesis; Osteoporosis; Overweight; Patients; Phosphorylation; Prevention; Process; Protein Isoforms; Protein Tyrosine Kinase; Psychological reinforcement; Regimen; Regulation; Research; Research Training; Resources; Risk; Role; Signal Transduction; Signaling Molecule; Site; Stress; Stress Fibers; Structure; United States; Walking; base; bone; bone cell; bone health; bone mass; bone quality; career; design; human FRAP1 protein; improved; in vivo; lifetime risk; lipid biosynthesis; novel; obesity in children; osteogenic; prevent; protein expression; public health relevance; sedentary; skeletal; src-Family Kinases

DESCRIPTION (provided by applicant): Spatial, chemical, and mechanical signals all contribute to lineage allocation of pluripotent mesenchymal stem cells (MSCs). When the fate of MSCs tips in favor of adipogenesis and away from osteogenesis in conditions such as unloading, aging, or estrogen deficiency, bone quality is diminished and risk of fracture increases. Dynamic skeletal loading inhibits adipogenesis in vitro and in vivo by enhancing ¿-catenin activity in MSCs. MSC potential is preserved by a signaling cascade, which is initiated at focal adhesions (FAs) setting off a cascade of mTORC2 to Akt to GSK3¿ and ¿-catenin. How mTORC2 is activated by force at the FA is unknown. Our preliminary data suggests mTORC2 requires Src for activation. Src kinases participate in mechanically regulated signaling events notably in activating RhoA necessary for new FA formation. Our data indicates that mTORC2 is required for RhoA activation, suggesting that the requirement of Src in RhoA activation may be indirect via the activation of mTORC2. The focus of this proposal will be to examine the role of Src kinases in strain-dependent mTORC2 activation and the contribution of those signaling events to cytoskeletal adaptation. These questions will be examined through the following specific aims: 1) determine how mechanical activation of Src-family kinases causes mTORC2 activation; 2) define the role of mTORC2 in force-dependent RhoA activation; 3) determine if mechanical activation of Src is enhanced by cytoskeletal adaptation. Pharmacological inhibition/knockdown studies will be performed using primary marrow-derived MSC to examine Src kinases and other signaling molecules associated with mechanical regulation of cytoskeletal remodeling. These studies have implications for understanding the mechanism by which mechanical loading regulates cytoskeletal assembly and reinforcement, a process essential for proper regulation of mechanosensation and cytoskeletal adaptation. The research training outlined in this proposal, combined with an outstanding mentoring committee and the ample resources of UNC provide the perfect environment to foster the necessary scientific growth to launch a productive, independent academic research career.

描述（由申请人提供）：空间、化学和机械信号都有助于多能间充质干细胞（MSC）的谱系分配。 当MSC的命运倾向于脂肪生成而远离骨生成时，如卸载，老化或雌激素缺乏，骨质量降低，骨折风险增加。 动态骨骼负荷通过增强MSC中的β-连环蛋白活性抑制体外和体内脂肪形成。MSC的潜能通过信号级联反应得以保持，该信号级联反应在局灶性粘连（FA）处启动，从而引发细胞增殖的级联反应。 mTORC 2至 Akt与 GSK 3和 连环蛋白mTORC 2如何在FA处被强制激活尚不清楚。我们的初步数据表明mTORC 2需要Src激活。 Src激酶参与机械调节的信号传导事件，特别是激活新FA形成所必需的RhoA。 我们的数据表明，mTORC 2是RhoA激活所必需的，这表明Src在RhoA激活中的需求可能是间接通过mTORC 2的激活。 本提案的重点将是研究Src激酶在应变依赖性mTORC 2激活中的作用以及这些信号事件对细胞骨架适应的贡献。 这些问题将通过以下具体目标进行检查：1）确定Src家族激酶的机械激活如何导致mTORC 2激活; 2）定义mTORC 2在力依赖性RhoA激活中的作用; 3）确定Src的机械激活是否通过细胞骨架适应增强。 将使用原代骨髓来源的MSC进行药理学抑制/敲低研究，以检查Src激酶和其他与细胞骨架重塑的机械调节相关的信号分子。 这些研究的影响，了解机械负荷调节细胞骨架组装和加固，机械感觉和细胞骨架适应的适当调节的过程中必不可少的机制。 本提案中概述的研究培训，加上优秀的指导委员会和充足的资源，为促进必要的科学成长提供了完美的环境，以启动富有成效的独立学术研究生涯。