Effect of chronic alcohol on ischemic injury and endothelial cells

描述(申请人提供)：动物研究已经证实，雌激素(E2)是一种已知的心脏保护激素，有助于在受损心脏中招募骨髓来源的内皮祖细胞/干细胞(EPC)，后者进而参与受损组织的血管修复。我们和其他人已经证明，补充E2增加了去卵巢(OVX)小鼠对乙醇的消耗。然而，酒精/雌激素的相互作用是否改变了内皮祖细胞的生物学特性，或者微环境(酒精)的变化是否与已知的E2对内皮祖细胞介导的心肌修复的有益影响相竞争尚不清楚。我们提出的研究的前提是基于我们已发表的和初步的观察结果：a)补充E2(17b-雌二醇)的OVX小鼠比接受安慰剂的OVX小鼠消耗更多的乙醇；b)E2介导的裸露颈动脉内皮化和E2介导的缺血后肢血管形成和血流恢复在饮用乙醇的小鼠中被钝化，尽管补充了E2；c)在急性心肌梗死小鼠模型中，补充E2后增加的酒精消耗以eNOS和MMP9依赖的方式减少了EPC的动员和归巢到缺血组织，抑制了生理和解剖组织修复并抑制了新生血管的生成；D)在体外，乙醇剂量依赖性地抑制E2诱导的EPC和成熟内皮细胞(EC)的增殖、小管形成和存活；干扰雌激素受体的基因组和非基因组功能，并将E2介导的细胞生存信号转换为促凋亡信号。因此，我们的中心假设是，酒精消耗量的增加与E2介导的梗死后心肌修复竞争，因为它否定了E2对EPC功能和信号的保护作用。本提案中描述的实验旨在通过检验根据以下三个具体目标分组的一系列假设来扩展这些发现：1)确定单个雌激素受体(ER)在乙醇介导的抑制BM-EPC动员和急性心肌梗死后心肌修复中的作用；2)确定eNOS和MMP9在乙醇抑制E2诱导的BM-EPC动员和急性心肌梗死后心肌修复中的作用；3)阐明乙醇介导的抑制E2诱导的EPC细胞存活的信号通路中涉及的分子信号。

DESCRIPTION (provided by applicant): Animal studies have established that estrogen (E2) is a known cardio-protective hormone that helps recruit bone-marrow derived endothelial progenitor/stem cells (EPC) in the injured heart which, in turn, participate in the vascular repair of injured tissue. We and others have shown that E2-supplementation enhances the consumption of ethanol in ovariectomized (OVX) mice. However, whether alcohol/estrogen interactions alter the biology of EPCs or whether change in the microenvironment (alcohol) competes with the known beneficial effects of E2 on EPC-mediated myocardial repair is not known. The premise of our proposed research is based on our following published and preliminary observations: a) OVX mice receiving E2 (17b-estradiol) supplementation consume significantly more ethanol compared to those receiving placebo; b) E2-mediated re-endothelialization in denuded carotid arteries and E2-mediated neo-vascularization and blood flow recovery in ischemic hind limbs is blunted in mice consuming ethanol, despite E2 supplementation; c) in a mouse model of acute myocardial infarction (AMI) increased ethanol consumption following E2-supplementation reduces EPC mobilization and homing to ischemic tissues in eNOS and MMP9 dependent manner, depresses physiological and anatomical tissue repair and represses neo-vasculogenesis; d) in vitro, ethanol dose-dependently attenuates E2-induced proliferation, tubulogenesis and survival of both EPCs and mature endothelial cells (EC); interferes with genomic and non-genomic functions of estrogen receptors and switches the E2-mediated cell survival signaling to the induction of pro-apoptotic signaling. Our central hypothesis, therefore, is that increased ethanol consumption competes with E2-mediated post-infarct myocardial repair by negating the protective effects of E2 on EPC function and signaling. The experiments described in the current proposal are designed to extend these findings by testing a series of hypotheses grouped according to the following 3 specific aims: 1) Determine the role of individual estrogen receptors (ER) on ethanol-mediated repression of BM-EPC mobilization and post-AMI myocardial repair, 2) Define the role of eNOS and MMP9 in ethanol repression of E2-induced BM-EPC mobilization and function in post-AMI myocardial repair and 3) Elucidate molecular signaling involved in the ethanol-mediated suppression of E2-induced cell survival signaling pathways in EPC.