PKC Isozymes In Hypoxia-Induced Fibroblast Proliferation

缺氧诱导的成纤维细胞增殖中的 PKC 同工酶

• 批准号: 6638654
• 负责人: MITA DAS
• 金额: $ 30.2万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6638654
• 关键词: animal tissue; cell population study; cell proliferation; enzyme induction /repression; fibroblasts; hypoxia; isozymes; mitogen activated protein kinase; protein kinase C; protein localization; pulmonary artery; tissue /cell culture; vascular resistance

DESCRIPTION (Applicant's Abstract): In the pulmonary artery (PA), the earliest and most dramatic growth in response to chronic hypoxia occurs in the adventitial compartment where the fibroblast resides. The adventitial thickening in response to hypoxia is especially impressive during the neonatal period and clearly contributes to the marked increase in pulmonary vascular resistance observed. Recent studies suggest the existence of multiple phenotypically and functionally distinct fibroblast subpopulations in adventitia. We have found that one subpopulation of fibroblasts proliferates rapidly in response to hypoxia, while another group lacks this response. Interestingly we have also demonstrated that the number of subpopulations which have the unique capability to replicate in response to hypoxia are higher in adventitia of hypoxic hypertensive calves compared to the control calves. Our overall goal is to define the signaling mechanisms that confer the ability to proliferate under hypoxic conditions to only specific PA adventitial fibroblast subpopulations. We have demonstrated that hypoxia-induced growth of PA adventitial fibroblasts is dependent on protein kinase C (PKC) activation. We have also shown that hypoxia can activate PKC isozymes in fibroblasts in a manner that mimics other growth-promoting stimuli. Our preliminary studies have shown 1) the expression of seven out of twelve described PKC isozymes in PA adventitial fibroblasts and 2) unique nuclear localization patterns of PKC isozymes in fibroblasts consistent with other observations demonstrating that isozyme location has specific functional consequences. We propose to evaluate the hypothesis that hypoxia-induced differential expression, localization and activation pattern of PKC isozymes will allow discrimination between "hypoxia-responsive" and "hypoxia-nonresponsive" fibroblast subpopulations in adventitia and that hypoxia-induced proliferation is mediated through the activation of only selective PKC isozymes. Our preliminary data have also demonstrated that hypoxia activates mitogen activated protein kinases, ERK1 and ERK2, and that activation is necessary for hypoxic proliferation of fibroblasts. Therefore, we will also test the hypothesis that hypoxia-induced activation of ERK1 and ERK2 is mediated through specific PKC isozymes and this selective interaction of PKC/ERK leads to proliferation in cells. Successful completion of the proposed experiments is likely to provide new insights into the role of distinct fibroblast subpopulations in pulmonary vascular disease. A better understanding of the signaling mechanisms contributing to cell proliferation in select fibroblast subpopulations during hypoxia-induced pulmonary hypertension could lead to the development of improved therapeutic strategies to treat chronic hypoxic pulmonary diseases.

描述（申请人的摘要）：在肺动脉（PA）中，最早 响应慢性缺氧的大多数戏剧性生长发生在 成纤维细胞居住的外给室。外来 在新生儿期间，对缺氧的响应增厚尤其令人印象深刻 周期并明显导致肺血管的明显增加 抗性观察到。最近的研究表明存在多重 表型和功能上不同的成纤维细胞亚群 Addingitia。我们发现成纤维细胞的一个亚群增殖 迅速响应缺氧，而另一组缺乏这种反应。 有趣的是，我们还证明了亚种数的数量 具有响应缺氧而复制的独特能力较高 与对照犊牛相比，低氧高血压犊牛的外膜。我们的 总体目标是定义赋予能力的信号传导机制 在低氧条件下扩散至特定的PA外膜成纤维细胞 亚群。我们已经证明了缺氧诱导的PA的生长 外膜成纤维细胞取决于蛋白激酶C（PKC）活化。我们 还表明缺氧可以激活A中成纤维细胞中的PKC同工酶 模仿其他促进生长的刺激的方式。我们的初步研究 显示1）十二个描述的PKC同工酶中七个表达的表达 pkc的异纤维细胞和2）独特的核定位模式 成纤维细胞中的同工酶与其他观察结果一致，表明 同工酶位置具有特定的功能后果。我们建议评估 缺氧引起的差异表达，定位和 PKC同工酶的激活模式将允许区分 “缺氧反应性”和“缺氧非反应性”成纤维细胞亚群 院和缺氧引起的增殖是通过 仅选择性PKC同工酶的激活。我们的初步数据也 证明缺氧激活有丝分裂激活的蛋白激酶ERK1和 ERK2，这种激活对于低氧增殖是必需的 成纤维细胞。因此，我们还将测试缺氧诱导的假设 ERK1和ERK2的激活是通过特定的PKC同工酶介导的，这 PKC/ERK的选择性相互作用会导致细胞增殖。成功的 拟议实验的完成可能会提供新的见解 独特的成纤维细胞亚群在肺血管疾病中的作用。一个 更好地了解有助于细胞的信号传导机制 在缺氧诱导的过程中，精选成纤维细胞亚群的增殖 肺动脉高压可能导致改善治疗的发展 治疗慢性低氧肺部疾病的策略。