Early Growth Response-1 (Egr-1), PKC Beta and Restenosis

早期生长反应-1 (Egr-1)、PKC Beta 和再狭窄

• 批准号: 7078584
• 负责人: SHI FANG YAN
• 金额: $ 31.93万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7078584
• 关键词: artery; blood vessel disorder; blood vessel prosthesis; diabetes mellitus; gel mobility shift assay; genetically modified animals; genotype; laboratory mouse; muscle cells; pathologic process; polymerase chain reaction; postoperative state; protein kinase C; protein structure function; regulatory gene; restenosis; transcription factor; vascular endothelium; vascular smooth muscle

DESCRIPTION (provided by applicant): Restenosis, or recurrent lumenal narrowing, is a significant clinical problem that is especially enhanced in diabetes. With the advent of sirolimus-coated stents, the risk of restenosis after angioplasty has been strikingly reduced. Recent studies suggest the potentially powerful impact of combination therapy, such as with glycoprotein IIb/IIIa inhibitors. Therefore, it is critical to fully dissect the molecular mechanisms underlying aberrant neointimal expansion after angioplasty, as identification of new and powerful adjunctive therapies will accelerate effective therapeutic intervention strategies, particularly in diabetic subjects. Our laboratory has focused on the role of the immediate early gene, early growth response-1 (egr-1) and its key upstream regulator, PKCb, in the response to acute arterial injury. Recent observations underscored the concept that upregulation of egr-1 is linked to chronic vascular/inflammatory stress, as transcripts for egr-1 are strikingly upregulated in human and murine atherosclerotic lesions compared to adjacent non-atheromatous plaque, and after denuding arterial injury in rodents. In the vessel wall subjected to acute denuding injury in wild-type C57BL/6 mice, egr-1 is expressed rapidly after injury, particularly in smooth muscle cells (SMC) and endothelial cells (EC); in hypercholesterolemic apolipoprotein E (apo E) null (0) mice, egr-1 is also upregulated in mononuclear phagocytes (MP) infiltrating the acutely injured vessel. Our studies support a role for egr-1 and its upstream regulator, PKCBetaII in processes linked to neointimal expansion after arterial injury; mice genetically deficient in egr-1 or PKCbeta display significantly decreased neointimal expansion after femoral artery denudation injury. These considerations lead us to hypothesize that acute arterial injury results in rapid activation of PKCbetaII, thereby driving upregulation of egr-1; mechanisms linked importantly to EC, SMC, and MP activation, and modulation of neointimal expansion. We propose to dissect the mechanisms by which the PKCbetaII/egr-1 axis contributes to restenosis in vivo. To test these concepts, we will generate and characterize transgenic mice expressing functionally deficient (dominant negative, DN PKCbetaII) under the control of promoters to direct expression to EC, SMC and MP. The impact of acute denuding arterial injury in euglycemic and diabetic mice, and littermate controls will be studied. If successful, these studies will elucidate the precise cell-specific and signaling pathways by which the PKCbeta/egr-1 axis modulates the response to arterial injury and identify if these pathways are logical targets for therapeutic intervention in arterial injury.

描述（由申请人提供）：再狭窄，或复发性管腔狭窄，是一个重要的临床问题，尤其是在糖尿病中。随着西罗莫司涂层支架的出现，血管成形术后再狭窄的风险显著降低。最近的研究表明，联合治疗具有潜在的强大影响，例如与糖蛋白IIb/IIIa抑制剂联合治疗。因此，充分剖析血管成形术后异常新生内膜扩张的分子机制是至关重要的，因为确定新的和强大的辅助疗法将加速有效的治疗干预策略，特别是在糖尿病患者中。我们的实验室专注于即时早期基因，早期生长反应-1 （egr-1）及其关键的上游调节因子PKCb在急性动脉损伤反应中的作用。最近的观察结果强调了egr-1的上调与慢性血管/炎症应激有关的概念，因为与邻近的非动脉粥样硬化斑块相比，egr-1的转录物在人和小鼠动脉粥样硬化病变中显著上调，并且在啮齿动物的剥脱动脉损伤后。野生型C57BL/6小鼠急性剥脱损伤血管壁中，egr-1在损伤后迅速表达，尤其是在平滑肌细胞（SMC）和内皮细胞（EC）中；在高胆固醇血症载脂蛋白E （apo E）缺失(0)的小鼠中，egr-1在浸润急性损伤血管的单核吞噬细胞（MP）中也上调。我们的研究支持egr-1及其上游调节因子PKCBetaII在动脉损伤后新内膜扩张相关过程中的作用；基因缺乏egr-1或pkcβ的小鼠在股动脉剥脱损伤后新内膜扩张明显减少。这些考虑使我们假设急性动脉损伤导致PKCbetaII的快速激活，从而推动egr-1的上调；与EC、SMC和MP激活以及新内膜扩张调节相关的重要机制。我们建议剖析PKCbetaII/egr-1轴在体内促进再狭窄的机制。为了验证这些概念，我们将产生并表征在启动子控制下表达功能缺陷（显性阴性，DN PKCbetaII）的转基因小鼠，以直接表达EC， SMC和MP。我们将研究急性剥脱性动脉损伤对正常血糖和糖尿病小鼠以及同窝对照的影响。如果成功，这些研究将阐明pkcβ /egr-1轴调节动脉损伤反应的精确细胞特异性和信号通路，并确定这些通路是否是动脉损伤治疗干预的逻辑目标。