TGF-beta and Smad3 in intimal hyperplasia after vascular bypass

描述(申请人提供)：每年有超过一百万的美国人需要介入治疗动脉粥样硬化性血管疾病。不幸的是，这些干预措施会引发复发的疾病或治疗后血管的再狭窄。尽管已经开发了预防性治疗，但10-15%的冠状动脉和高达80%的下肢介入治疗(取决于血管床)仍会发生再狭窄。对再狭窄机制的进一步了解将有助于改进治疗方法的发展。再狭窄有两个主要过程：1)新生内膜增厚，称为内膜增生；2)管壁直径改变，导致缩窄性或适应性重塑。我们之前的发现证实，转化生长因子在这两个过程中都是一个主导因素。细胞因子转化生长因子在血管疾病中的作用一直是一个难题，因为在体外，转化生长因子会产生高度分化的平滑肌细胞(SMC)表型，而在体内，转化生长因子会刺激SMC去分化和内膜增生。在过去的授权期内，我们发现了对这一难题的独特解释：血管干预后Smad3水平升高，将Tg？转化为SMC去分化、增殖、迁移和炎症(MCP-1产生)的刺激剂和细胞凋亡的抑制因子，所有这些标志性行为都会促进内膜增生。令人惊讶的是，动脉介入治疗后升高的转化生长因子和Smad3水平也会产生适应性重塑或血管壁扩张的有利副产品。受到这些具有挑衅性的发现的启发，我们渴望继续我们对转化生长因子？/Smad3的研究，以期1)进一步深入了解转化生长因子？S在再狭窄病理生理学中的作用，2)开发通过操纵平滑肌细胞去分化来抑制再狭窄的新策略，以及3)开发通过阻断Smad依赖和非Smad依赖的转化生长因子？信号来抑制再狭窄的治疗策略。在特定的目标-1中，我们将利用一系列产生Smad3反应基因差异表达的突变体，剖析和区分转化生长因子/Smad3刺激内膜增生(促进再狭窄)和适应性重塑(抗再狭窄)的途径。在特定的目标-2中，我们旨在通过阻断去分化和/或促进分化可以防止内膜增生的理论，更好地了解转化生长因子B/Smad3导致SMC去分化的因素。在特定的AIM-3中，我们将确定Smad非依赖通路在转化生长因子诱导的再狭窄中的作用，然后设计联合疗法，用Smad3抑制肽同时阻断Smad3信号转导通路，并用它们的特异性抑制剂阻断非Smad通路(S)。我们的最终目标是找到有效防止血管复发的药物，每年影响数十万患者的复发血管疾病。

DESCRIPTION (provided by applicant): Every year more than one million Americans require interventions to treat atherosclerotic vascular disease. Unfortunately these interventions trigger the development of recurrent disease or restenosis of the treated vessel. Although preventative therapies have been developed, restenosis still develops in 10-15% of coronary and up to 80% of lower extremity interventions (depending upon the vascular bed). Further insights into the mechanisms that underlie restenosis will aid in the development of improved therapeutics. Two major processes contribute to restenosis: 1) thickening of the neointima, termed intimal hyperplasia, and 2) changes in the vessel wall diameter resulting in either constrictive or adaptive remodeling. Our previous discoveries verify that TGFß is a dominant factor involved in both of these processes. The role of the cytokine TGFß in vascular disease has been a conundrum because of the paradox that in vitro, TGFß produces a highly differentiated smooth muscle cell (SMC) phenotype, however in vivo, TGFß stimulates SMC de-differentiation and intimal hyperplasia. We have discovered over the past grant period, a unique explanation for this conundrum: elevated levels of Smad3 that develop following vascular intervention, transform TGß into a stimulant of SMC de-differentiation, proliferation, migration and inflammation (MCP-1 production), and an inhibitor of apoptosis, all signature behaviors that promote intimal hyperplasia. Surprisingly, elevated levels of TGFß and Smad3 following arterial intervention also produce the favorable by-product of adaptive remodeling or vessel wall expansion. Inspired by these provocative findings, we are eager to continue our investigations of TGFß/Smad3 with the goal of 1) gaining further insights into TGFß's role in the pathophysiology of restenosis, 2) developing new strategies to inhibit restenosis by manipulating SMC de-differentiation and 3) developing therapeutic strategies to inhibit restenosis by blocking both Smad-dependent and Smad-independent TGFß signaling. In Specific Aim-1, we will dissect and differentiate the pathways through which TGFß/Smad3 stimulates intimal hyperplasia (pro-restenosis) versus adaptive remodeling (anti-restenosis), taking advantage of a series of mutants that produce differential expression of Smad3-responsive genes. In Specific Aim-2, we aim to better understand the factors through which TGFß/Smad3 produces SMC de- differentiation with the theory that blocking de-differentiation and/or enhancing differentiation will prevent intimal hyperplasia. In Specific Aim-3, we will determine the role of Smad-independent pathways in TGFß- induced restenosis, and then design combination therapies to simultaneously block Smad3 signaling with a Smad3-inhibiting peptide, and non-Smad pathway(s) with their specific inhibitors. Our ultimate goal is to identify agents that effectively prevent the development of recurrent vascular disease, a process affecting hundreds of thousands of patients each year.