INTEGRINS IN KIDNEY MORPHOGENESIS

在肾脏的发育和从损伤中恢复过程中，一个关键 形态发生的步骤是肾小管上皮细胞的极化。 肾上皮细胞的极化依赖于相互作用 细胞和细胞外基质，以及细胞与细胞之间的接触。虽然 负责将这些粘合事件转化为 形态发生信号未知，主要候选者是整合素，a 细胞黏附分子超家族。已知整合素是 多种细胞外基质蛋白的受体及其相互作用 肌动蛋白细胞骨架。最近，人们认识到 它们还参与细胞与细胞之间的相互作用。其他信息 提示整合素可能影响细胞分化和 扩散，可能是通过产生第二信使。近期 有证据表明，整合素在 不同的肾单位节段，并可能在发育过程中发挥关键作用 凝聚间充质的极化。整合素也可能是 急性肾功能衰竭病理生理学中的重要因素。在这 整合素参与上皮极化的项目将是 使用互补的体外和体内方法进行研究。这个 MDCK细胞表达的整合素的功能将被研究 细胞黏附分析及免疫细胞化学和生化技术 利用亚基特异性的单克隆和多克隆抗体和cDNA 探头(具体目标1A)。整合素的表达、分布、激活 将在极化过程中和#年检查目标 细胞在不同的底物上和在扰动条件下培养 细胞-细胞接触(特定目标lb)。干扰整合素的作用 对MDCK细胞极性的作用将用 干扰整合素配体结合和表达的抗体 MDCK细胞中整合素cDNA和反义结构的研究。(具体目标 立法会)。整合素在肾脏分化过程中的作用 在小鼠胚胎、整个器官培养和移植培养中进行了研究 利用封闭抗体和反义构建物构建肾原基 (具体目标2 A)。整合素在再生过程中的表达变化 在活体内将在小鼠肾脏中进行检查，通过夹闭 肾动脉(特异性靶点2B)。从长远来看，这些措施的结果 实验将提供有关分子的重要信息。 细胞诱导肾脏极化的相互作用 粘附力。这些研究也将有助于我们理解肾脏是如何 上皮细胞发育并从损伤中恢复。

In the development of the kidney and in its recovery from injury, a key step in morphogenesis is polarization of the tubule epithelial cells. Polarization of kidney epithelial cells depends on interactions between cells and the extracellular matrix, and on cell-cell contacts. Although the molecules responsible for transducing these adhesive events into morphogenetic signals are unknown, prime candidates are the integrins, a superfamily of cell adhesion molecules. Integrins are known to be receptors for a variety of extracellular matrix proteins and to associate with the actin cytoskeleton. More recently it has been recognized that they are also involved in cell-cell interactions. Other information suggests that integrins may influence cell differentiation and proliferation, possibly through generation of second messengers. Recent evidence suggests that integrins are characteristically expressed in distinct nephron segments and may play a key role during development in the polarization of the condensed mesenchyme. Integrins may also be significant factors in the pathophysiology of acute renal failure. In this project the involvement of integrins in epithelial polarization will be investigated using complementary in vitro and in vivo approaches. The functions of integrins expressed by MDCK cells will be investigated with cell adhesion assays and immunocytochemical and biochemical techniques using subunit-specific monoclonaI and polyclonaI antibodies and cDNA probes (Specific Aim 1A). Integrin expression, distribution, activation, and targeting will be examined during the polarization process and in cells cultured on different substrata and under conditions which perturb cell-cell contacts (Specific Aim lB). The effects of disrupting integrin function on the polarity of MDCK cells will be investigated with antibodies that interfere with integrin ligand binding and by expression of integrin cDNAs and antisense constructs in MDCK cells. (Specific Aim lC). Integrin function during differentiation of the kidney will be studied in mouse embryos, whole organ cultures, and transfer cultures of kidney primordia using blocking antibodies and antisense constructs (Specific Aim 2A). Alterations in integrin expression during regeneration in vivo will be examined in mouse kidneys made ischemic by clamping of the renal artery (Specific Aim 2B). In the long-term, the results of these experiments will provide important information on the molecular interactions responsible for induction of kidney polarization by cell adhesion. These studies will also aid our understanding of how the kidney epithelium develops and recovers from injury.