Mechanotransduction in bladder smooth muscle

膀胱平滑肌的机械传导

• 批准号: 7626379
• 负责人: Rosalyn M Adam
• 金额: $ 34万
• 依托单位: BOSTON CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-22 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7626379
• 关键词: 1-Phosphatidylinositol 4-Kinase; Address; Animal Model; Attenuated; Award; Bladder; Bladder Diseases; Bladder Dysfunction; Cells; Cellular Mechanotransduction; Computer Simulation; DNA biosynthesis; Data; Diabetes Mellitus; Differentiation and Growth; Disease; Drug Delivery Systems; Environment; Event; Family member; Functional disorder; Funding; Gene Expression; Gene Targeting; Genome; Goals; Grant; Growth; Human; Hypertrophy; In Vitro; Laboratories; Lead; Light; Manuscripts; Mechanical Stimulation; Mechanics; Mediating; Mediator of activation protein; Modeling; Molecular; Molecular Profiling; Molecular Target; Muscle; National Institute of Diabetes and Digestive and Kidney Diseases; Neurogenic Bladder; Obstruction; Organ; Pathologic; Pathology; Pathway interactions; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Physiology; Platelet-Derived Growth Factor; Process; Protein Family; Protein Inhibition; Protein-Serine-Threonine Kinases; Publishing; RNA Interference; Regulation; Regulator Genes; Reporting; Rodent; Role; Secondary to; Signal Transduction; Site; Smooth Muscle; Smooth Muscle Myocytes; Stimulus; Stretching; Technology; Testing; Therapeutic Intervention; Tissues; Transcription Factor AP-1; Urinary tract; Work; abstracting; base; cell growth; effective therapy; genome-wide; in vitro Model; in vivo; insight; jun Oncogene; novel; research study; response; small hairpin RNA; therapeutic target; treatment strategy

DESCRIPTION (provided by applicant): Project Abstract Fibroproliferative remodeling in the urinary tract is associated with a number of pathologies including hypertrophic bladder growth secondary to outlet obstruction, neurogenic bladder and diabetes. Although the macroscopic changes that occur in the bladder wall exposed to pathologic stimulation, such as wall thickening and loss of muscle contractility, have been appreciated for many years, the signals that underlie tissue remodeling at the molecular level are still poorly understood. The goal of the proposed studies is to uncover the signaling events that regulate growth and differentiation of bladder smooth muscle in response to pathologic stimuli. The identification of key regulators of these processes will reveal novel targets for therapeutic intervention. Because the bladder is unique among hollow organs as a privileged site for drug delivery, these studies may lead directly to opportunities for novel therapies for urinary tract dysfunction particularly in the context of hypertrophy. Data from our group have implicated the phosphoinositide-3-kinase (PI3K)/Akt pathway as a mediator of primary bladder smooth muscle cell (BSMC) growth in response to mechanical stimulation or platelet- derived growth factor (PDGF) treatment. Exposure of SMC to stretch or PDGF in vitro or distension of the intact rodent bladder ex vivo elicited robust phosphorylation of the serine-threonine kinase Akt, a principal effector of PI3K. Expression profiling of primary human BSMC revealed stretch to be a highly selective regulator of gene expression, with <0.2% of the expressed genome identified as mechanically responsive. In silico analysis implicated AP-1 family members as potential regulators of stretch-induced BSMC gene expression. Although Akt and AP-1 are upregulated by mechanical stimuli, the extent to which they interact to regulate hollow organ remodeling is essentially completely unstudied. In this proposal we will test the hypothesis that Akt- and AP-1-regulated signals mediate growth of bladder smooth muscle in response to mechanical stimulation and converge at one or more levels within the cell. We will use an in vitro model of BSMC stretch as well as an animal model of bladder distension to address the following specific aims: (1) Determine how Akt regulates growth in SMC exposed to mechanical stimuli in vitro and in vivo; (2) Determine how AP-1-mediated changes in gene expression regulate SMC growth and the extent of regulation by Akt. We will use several complementary approaches to modulate Akt- and AP-1-dependent signaling in BSMC in vitro and in vivo, including RNA interference, pharmacologic inhibition and protein transduction technology. We anticipate that findings from these experiments will provide novel insights into the mechanisms underlying pathologic bladder smooth muscle growth.Project Narrative Effective treatment of bladder diseases is hampered by a lack of understanding about the molecular signals that regulate tissue growth both in normal and pathologic situations. The proposed experiments will investigate how two protein families, Akt and AP-1, interact to regulate the growth of bladder smooth muscle in response to mechanical stimulation. We anticipate this analysis will shed new light on fundamental mechanisms underlying bladder muscle physiology and may also provide insight into new treatment strategies.

描述（由申请人提供）：项目摘要泌尿道中的纤维增殖性重塑与许多病理学相关，包括继发于出口梗阻的肥大性膀胱生长、神经源性膀胱和糖尿病。尽管膀胱壁在受到病理刺激时发生的宏观变化（例如壁增厚和肌肉收缩力丧失）多年来一直受到人们的重视，但对分子水平上组织重塑背后的信号仍然知之甚少。拟议研究的目标是揭示调节膀胱平滑肌响应病理刺激的生长和分化的信号事件。这些过程的关键调节因子的识别将揭示治疗干预的新目标。由于膀胱在中空器官中是独一无二的，作为药物输送的特殊部位，这些研究可能直接为尿路功能障碍的新疗法带来机会，特别是在肥大的情况下。我们小组的数据表明，磷酸肌醇 3 激酶 (PI3K)/Akt 通路是原代膀胱平滑肌细胞 (BSMC) 响应机械刺激或血小板衍生生长因子 (PDGF) 治疗而生长的介质。将 SMC 暴露于体外拉伸或 PDGF 或离体完整啮齿类动物膀胱的扩张会引发丝氨酸-苏氨酸激酶 Akt（PI3K 的主要效应器）的强烈磷酸化。原代人 BSMC 的表达谱显示，拉伸是基因表达的高度选择性调节剂，<0.2% 的表达基因组被确定为机械响应。计算机分析表明 AP-1 家族成员是拉伸诱导的 BSMC 基因表达的潜在调节因子。尽管 Akt 和 AP-1 受到机械刺激的上调，但它们相互作用调节中空器官重塑的程度基本上尚未被研究。在本提案中，我们将测试以下假设：Akt 和 AP-1 调节信号介导膀胱平滑肌响应机械刺激的生长，并在细胞内的一个或多个水平上汇聚。我们将使用 BSMC 拉伸的体外模型以及膀胱扩张的动物模型来实现以下具体目标：（1）确定 Akt 如何调节暴露于体外和体内机械刺激的 SMC 的生长； (2) 确定 AP-1 介导的基因表达变化如何调节 SMC 生长以及 Akt 的调节程度。我们将使用多种互补方法在体外和体内调节 BSMC 中的 Akt 和 AP-1 依赖性信号传导，包括 RNA 干扰、药理学抑制和蛋白质转导技术。我们预计这些实验的结果将为病理性膀胱平滑肌生长的机制提供新的见解。项目叙述由于对正常和病理情况下调节组织生长的分子信号缺乏了解，阻碍了膀胱疾病的有效治疗。拟议的实验将研究 Akt 和 AP-1 这两个蛋白质家族如何相互作用来调节膀胱平滑肌响应机械刺激的生长。我们预计这一分析将为膀胱肌肉生理学的基本机制提供新的线索，并可能为新的治疗策略提供见解。