Integrin Shedding in the Heart: In vivo and in vitro

描述(申请人提供)：在儿童的成长和发展过程中 心脏，细胞外基质(ECM)的成分保持着精确的， 心肌细胞Z带附近有胶原附着的三维排列。 这种细胞外基质的排列与心脏功能密切相关， 这些连接的改变可能会导致异常生长和改变 图案化。细胞外基质的主要细胞表面受体是 整合素家族。然而，这些整合素连接的机制 随着ECM的变化，增长是未知的。对病理生理学的反应 信号心肌细胞经历大小(肥大)或形状的增加 (扩张)，细胞外基质：肌细胞连接也必须适应这些变化。 心脏成纤维细胞也表现出适应性变化，以响应生长和 胶原蛋白沉积、迁移和改变的发育信号 扩散。最近的数据表明，整合素与 ECM在生长和发育过程中摆脱了它们的外域；然而， 这一过程的机制和功能尚不清楚。拟议的研究将 解决整合素脱落代表一种改变方法的假设 受体-细胞外基质相互作用，允许细胞生长和表型变化 脱落整合素胞外结构域对心脏和心脏 成纤维细胞和肌细胞。解决这一假设的具体目标 目的是：1)确定哪些特定的整合素正在脱落；2)确定 负责脱毛的机制；以及3)确定潜在的功能 脱落的整合素胞外结构域，针对这些特定的目的，多种细胞 和分子技术在体内和体外心脏模型中的应用 将使用肥大和扩张。初步数据显示， 负责脱落的酶很可能是基质的成员 金属蛋白酶(MMPs)家族或去整合素和金属蛋白酶(ADAM) 一家人。将使用特定的抑制剂来确定哪些特定的 MMP或ADAMS参与了脱毛过程。多种生化产品 以及细胞行为分析，包括调节受体数量、胶原蛋白 合成、细胞迁移和胶原凝胶收缩将用于 确定SHIP片段在心肌细胞上的潜在功能 成纤维细胞。拟议的研究将从根本上提供有关 整合素、细胞外基质与心脏生长调控的动态相互作用 发展。

DESCRIPTION (provided by applicant): During the growth and development of the heart, the components of the extracellular matrix (ECM) maintain a precise, 3-dimensional arrangement with collagen attaching near the Z band of myocytes. This arrangement of the ECM is intimately associated with cardiac function and alteration of these connections can result in abnormal growth and altered patterning. The principal cell surface receptors for the ECM are the members of the integrin family. However, the mechanism of how these integrin connections with the ECM change with growth is unknown. In response to pathophysiological signals cardiac myocytes undergo an increase in size (hypertrophy) or shape (dilation), the ECM:myocyte connection also must accommodate these changes. Cardiac fibroblasts also show adaptive changes in response to growth and developmental signals by altered collagen deposition, migration, and proliferation. Recent data has demonstrated that the integrin connections with the ECM shed their ectodomains during growth and development; however, the mechanism and function of this process is unknown. The proposed research will address the hypothesis that integrin shedding represents a method of altering receptor-ECM interaction which allows for changes in cell growth and phenotype and that the shed integrin ectodomain has a regulatory function on both cardiac fibroblasts and myocytes. The specific aims that will addresses this hypothesis are to: 1) determine which specific integrins are being shed; 2) determine the mechanism responsible for shedding; and 3) determine the potential function of the shed integrin ectodomain, To address these specific aims, a variety of cell and molecular techniques in both in vivo and in vitro models of cardiac hypertrophy and dilation will be used. Preliminary data indicates that the enzymes responsible for the shedding are likely to be members of the Matrix Metalloprotease (MMP) family or A Disintegrin And Metalloprotease (ADAM) family. Specific inhibitors will be used to determine which of the specific MMPs or ADAMS are involved in the shedding process. A variety of biochemical and cell behavior assays including regulation of receptor number, collagen synthesis, cell migration and collagen gel contraction will be used to determine potential functions of the shed fragment on cardiac myocytes and fibroblasts. The proposed studies will provide fundamentally new information on the dynamic interaction of integrins, ECM and regulation of cardiac growth and development.