Role of Human Chymase in Smooth Muscle Contraction in Asthma

 描述（由申请人提供）：这是一份重新提交的K 08奖申请，申请人是加州大学旧金山分校弗朗西斯科（UCSF）医学系肺与重症监护科助理教授Aparna Sundaram博士。Sundaram博士正在努力使自己成为哮喘领域的独立调查员。Sundaram博士及其同事发表的最新数据表明，缺乏αvβ6整合素（调节TGF-β活性）的小鼠可免受气道过度活跃的影响。此外，这种作用部分是通过在不存在TGF-β的情况下上调小鼠肥大细胞蛋白酶4（mMCP-4）介导的。Sundaram博士发现，mMCP-4抑制了IL-13增强的小鼠气管环收缩。人类糜酶是mMCP-4最接近的直系同源物，Sundaram博士已经证明糜酶也能保护细胞免受IL-6的侵害。 13增强小鼠和人气道环的收缩。糜酶不通过影响肌动蛋白-肌球蛋白交联来调节收缩，因此Sundaram博士将重点放在它影响收缩装置与底层细胞外基质的连接的假设上。为了支持这一假设，Sundaram博士已经表明，糜酶切割纤连蛋白，并损害整合素介导的平滑肌细胞与纤连蛋白的粘附，但不损害胶原蛋白或玻连蛋白。此外，用RGD肽（在纤连蛋白上发现的整合素结合序列）处理气管环损害IL-13增强的收缩，并且用RGD肽和糜酶的组合处理不赋予比单独的RGD肽或糜酶更进一步的保护。 在这项提案中，Sundaram博士将系统地研究糜酶 调节收缩反应。她将探讨糜酶对整合素表达的影响，确定哪些特定的整合素在纤连蛋白介导的粘附中是重要的，研究整合素损失对局部粘连内的扩大，分布和信号传导的影响，以及对收缩的离体反应和对过敏原激发的体内反应的影响（目的1）。她还将进一步探索过敏原挑战和细胞因子暴露对揭示糜酶保护作用的作用。她将通过研究过敏原攻击对糜蛋白酶介导的保护和细胞外基质组织的影响来做到这一点。她还将研究各种细胞因子对整合素表达的影响及其对粘附、粘着斑复合物信号传导和凝乳酶介导的保护作用（目的2）。 围绕这些目标组织，并通过正式的导师和课程指导，Sundaram博士 将追求以下目标：（1）了解人类糜酶对尼古丁诱导的气道过度活跃的保护机制;（2）发展技能，专业知识，填补知识空白，使科学独立顺利过渡。Sundaram博士组建了UCSF教师的多元化和多学科指导团队，包括主要导师Dean Sheppard，医学教授和国际公认的整合素生物学专家，共同导师乔治Caughey，医学教授和肥大细胞生物学多产的基础科学研究员，以及委员会成员，包括Chris艾伦，解剖学助理教授，研究兴趣是哮喘的细胞免疫反应，Courtney布罗德斯，医学教授和肺部生物学中心副主任以及胸膜疾病的国际专家，和Laura Koth，医学副教授，其研究包括与哮喘和肉芽肿性肺病相关的转化研究。Sundaram博士的研究计划侧重于糜酶的新作用，加上她的结构化培训计划，将使她能够开发必要的 技能和初步数据的R 01赠款申请，以及建立一个独特的利基， 她的导师让她成为一个独立的医生科学家。

 DESCRIPTION (provided by applicant): This is a resubmission application for a K08 award for Dr. Aparna Sundaram, an Assistant Professor in the Division of Pulmonary & Critical Care, Department of Medicine, at the University of California, San Francisco (UCSF). Dr. Sundaram is working to establish herself as an independent investigator in the field of asthma. Recent data published by Dr. Sundaram and colleagues has suggested that mice lacking the αvβ6 integrin, which modulates TGF-β activity, are protected from airway hyperactivity. Furthermore, this effect is mediated in part by up-regulation of mouse mast cell protease 4 (mMCP-4) in the absence of TGF-β. Dr. Sundaram found that mMCP-4 inhibited IL-13 enhanced contraction in mouse tracheal rings. Human chymase is the closest orthologue of mMCP-4, and Dr. Sundaram has shown that chymase is also protective against IL- 13 enhanced contraction in both mouse and human airway rings. Chymase does not modulate contraction by affecting actin-myosin cross-bridging, so Dr. Sundaram has focused on the hypothesis that it affects linkage of the contractile apparatus to the underlying extracellular matrix. In support of this hypothesis, Dr. Sundaram has shown that chymase cleaves fibronectin, and impairs integrin-mediated adhesion of smooth muscle cells to fibronectin, but not collagen or vitronectin. Furthermore, treatment of tracheal rings with an RGD peptide (an integrin-binding sequence found on fibronectin) impairs IL-13 enhanced contraction, and combined treatment with RGD peptide and chymase does not confer further protection over either RGD peptide or chymase alone. In this proposal Dr. Sundaram will systematically investigate the mechanism by which chymase modulates contractile responses. She will explore the effect of chymase on integrin expression, determine which specific integrin(s) are important in fibronectin-mediated adhesion, investigate the effect of loss of integrin's on enlargement, distribution, and signaling within focal adhesions as well as effects on ex vivo responses to contraction and in vivo responses to allergen challenge (Aim 1). She will also further explore the role of allergen challenge and cytokine exposure on unmasking the protective effect of chymase. She will do this by investigating the effect of allergen challenge on chymase-mediated protection and organization of the extracellular matrix. She will also study the effect of various cytokines on integrin expression and their contribution to adhesion, focal adhesion complex signaling, and chymase-mediated protection (Aim 2). Organized around these aims and guided by both formal mentorship and coursework, Dr. Sundaram will pursue the following goals: (1) to understand the mechanism of protection against cytokine-induced airway hyperactivity by human chymase; and (2) to develop skills, expertise, and fill knowledge gaps to enable a smooth transition to scientific independence. Dr. Sundaram has assembled a diverse and multidisciplinary mentoring team of UCSF faculty including primary mentor Dean Sheppard, Professor of Medicine and an internationally recognized expert in integrin biology, co-mentor George Caughey, Professor of Medicine and a prolific basic science researcher in mast cell biology, and committee members including Chris Allen, Assistant Professor of Anatomy with research interests in cellular immune responses in asthma, Courtney Broaddus, Professor of Medicine and the Associate Director of the Lung Biology Center as well as international expert in pleural diseases, and Laura Koth, Associate Professor of Medicine whose research encompasses translational studies relating to asthma and granulomatous lung diseases. Dr. Sundaram's research proposal focusing on the novel role of chymase coupled with her structured training plan will allow her to develop the necessary skills and preliminary data for an R01 grant application as well as establish a niche distinct from her mentors to allow her to become an independent physician-scientist.