Molecular mechanisms of enhanced vascular smooth muscle

导致T2 DM再狭窄增加的分子机制尚不清楚。血管平滑肌 肌细胞（VSMC）增殖在血管损伤后的再狭窄中起关键作用，葡萄糖，胰岛素， 和氧化应激促进VSMC生长。此外，在T2 DM动物模型中， VSMC增殖对损伤的反应。白细胞12/15型脂氧合酶（12 LO）与 作为一个关键的介导者，在动物损伤后促进VSMC增殖和新生内膜形成 T2 DM模型我们的初步数据清楚地表明，12 LO调节VSMC的生长， 加速糖尿病损伤反应的潜在机制。我们进一步证明，12 LO诱导的 VSMC的增殖是由螺旋-环-螺旋转录因子Id 3介导的（Id 3是VSMC增殖的关键调节因子， 胰岛素和葡萄糖介导的基因转录）。我们已经在多种胰岛素模型中证明了 与2型DM相比，Id 3表达显著增加。机制研究表明， Id 3促进G1-S转变，导致VSMC生长增加， 丝氨酸5调节该事件。在这一更新申请中，我们建议扩展我们的体外机制， 研究结果和先前的体内表达研究表明，12 LO/ld 3途径是一个关键的调解人， 2型糖尿病动物模型中血管对损伤的反应。此外，我们建议 鉴定介导12 LO诱导的Id 3表达增加的顺式和反式作用元件， VSMC生长，并证实其在T2 DM损伤反应中的体内作用。 假设：2型糖尿病通过调节Id 3的表达来调节对血管损伤的反应， 活性和VSMC生长。这种作用是由12 LO诱导的核因子表达介导的， 增强的Id 3表达和/或Id 3的丝氨酸5磷酸化。将我们激动人心的发现从 在T2 DM中血管对损伤的反应的动物模型中的VSMC培养研究，并解决该问题 中心假设，我们提出以下目标。目标1：确定Id 3在 在饮食诱导的2型糖尿病小鼠模型中，对损伤的反应是加速新生内膜形成。 目的2：在体内评价12 LO/ld 3途径导致VSMC生长和病变形成加速。 目标3c。将体外研究结果扩展到体内，以证实Id 3启动子中的12 LO-反应元件 培养物中Id 3转录所需的蛋白质也调节体内Id 3转录以响应T2 DM中的损伤。

The molecular mechanisms that lead to increased restenosis in T2DM are unknown. Vascular smooth muscle cell (VSMC) proliferation plays a key role in restenosis following vascular injury, and glucose, insulin, and oxidative stress increase VSMC growth. Moreover, in animal models of T2DM, there is increased VSMC proliferation in response to injury. Leukocyte type 12/15 lipoxygenase (12LO) has been implicated as a key mediator of enhanced VSMC proliferation and neointimal formation in response to injury in animal models of T2DM. Our preliminary data clearly demonstrates that 12LO regulates VSMC growth, one potential mechanism for the accelerated response to injury in diabetes. We further demonstrate that 12LO-induced proliferation of VSMC is mediated by the helix-loop-helix transcription factor Id3 (a key regulator of insulin and glucose mediated gene transcription). We have demonstrated in multiple models of insulin resistance and type 2 DM, that Id3 expression is significantly increased. Mechanistic studies demonstrate that Id3 promotes G1-S transition leading to increased VSMC growth and that phosphorylation of Id3 on serine 5 regulates this event. In this renewal application, we propose to extend our in vitro mechanistic findings and previous in vivo expression studies to demonstrate that the 12LO/ld3 pathway is a key mediator of the vascular response to injury in vivo in animals models of type 2 DM. Furthermore, we propose to identify the cis and trans-acting elements that mediate 12LO-induced increases in Id3 expression and VSMC growth and confirm their role in vivo in the response to injury in T2DM . Hypotheses: Type 2 DM modulates the response to vascular injury via regulation of Id3 expression and activity and VSMC growth. This effect is mediated by 12LO-induced nuclear factor expression leading to enhanced Id3 expression and/or serine 5 phosphorylation of Id3. To extend our exciting findings from VSMC culture studies in vivo in an animals model of vascular response to injury in T2DM and to address this central hypothesis, we propose the following aims. Aim 1: Establish the essential role of Id3 in the accelerated neointimal formation in response to injury in diet-induced mouse models of type 2 DM. Aim 2: Evaluate in vivo the 12LO/ld3 pathway leading to accelerated VSMC growth and lesion formation. Aim 3c. Extend in vitro findings in vivo to confirm that the 12LO-response elements in the Id3 promoter required for Id3 transcription in culture also regulate Id3 transcription in vivo in response to injury in T2DM.