PKC-Delta in Intimal Hyperplasia after Vascular Bypass

描述(由申请人提供)： 在接受血管成形术或血管重建术的患者中，内膜增生(IH)是一种导致巨大发病率和死亡率的疾病过程，其典型特征是去分化的血管平滑肌细胞(VSMC)增殖、迁移并抵抗细胞凋亡。在初步研究中，我们发现蛋白激酶C的一个亚型，PKC增量(PKCd)，在体外对VSMCs有深刻的调节作用。具体地说，PKCd抑制SMC的增殖和迁移，刺激SMC的凋亡和分化。此外，我们还发现雷帕霉素通过冠状动脉支架可抑制再狭窄，增加培养的VSMCs的PKCd，提示PKCd可能是雷帕霉素发挥其深刻抑制作用的信号。在此基础上，我们认为PKCd对VSMCs的有效作用可能使该分子或其修饰被用作一种特定的预防性治疗。我们将从研究开始，确定PKCd影响VSMC增殖、凋亡和迁移的途径，并确认我们的初步数据显示，通过ERK1、p38和p53进行下游调控。在特定的目标2中，我们将剖析PKCd分子，以了解其在VSMC中的调控机制。具体地说，我们将评估催化或调节结构域以及特定酪氨酸残基的磷酸化，来调控PKCd对增殖、迁移和凋亡的控制。在特定的目标III中，我们将通过三种不同的分子操作来测试PKCd在大鼠和小鼠动脉损伤模型中的作用。最后，在第四个目标中，我们将在体内和体外验证这一假设，即雷帕霉素通过诱导PKCd影响SMC的行为和IH。我们期待这些研究将进一步加深我们对促进IH形成的机制和途径的了解。此外，我们对PKCd对伴随IH的SMC功能障碍的深刻影响感到鼓舞，并假设上调这种分子将是预防这种毁灭性疾病的潜在策略。

DESCRIPTION (provided by applicant): Intimal hyperplasia (IH), a disease process that accounts for tremendous morbidity and mortality in patients previously treated with angioplasty or vascular reconstruction, is typified by dedifferentiated vascular smooth muscle cells (VSMC) that proliferate, migrate, and are resistant to apoptosis. In preliminary studies, we found that a subtype of protein kinase C, PKC delta (PKCd), profoundly regulates VSMCs in vitro. Specifically, PKCd inhibits SMC proliferation and migration and stimulates SMC apoptosis and differentiation. Moreover, we found that rapamycin, which inhibits restenosis when applied via coronary stents, increases PKCd in cultured VSMCs, suggesting PKCd may be the signal through which rapamycin exerts its profound inhibitory effect. Based on the foregoing, we propose that the potent effects of PKCd on VSMCs might allow this molecule, or a modification, to be used as a specific preventative therapy. We will begin with studies to define the pathways through which PKCd affects VSMC proliferation, apoptosis, and migration and confirm our preliminary data showing downstream regulation through ERK1, p38 and p53. In specific aim II, we will dissect the PKCd molecule to understand the regulatory mechanism that governs its effects in VSMCs. Specifically; we will evaluate the ability of the catalytic or regulatory domain, as well as phosphorylation of specific tyrosine residues, to regulate PKCd's control over proliferation, migration and apoptosis. In specific aim III, we will test the role of PKCd through three distinct molecular manipulations in rat and mouse arterial injury models. Finally, in aim IV, we will test the hypothesis, both in vivo and in vitro, that rapamycin affects SMC behavior and IH through induction of PKCd. We anticipate that these studies will further our knowledge of the mechanisms and pathways that contribute to the formation of IH. Moreover, we are encouraged by the profound effect that PKCd has on the SMC dysfunction that accompanies IH and postulate that upregulation of this molecule will be a potential strategy for the prevention of this devastating condition.