Dedicator of Cytokinesis 2 in smooth muscle phenotype modulation

细胞分裂 2 在平滑肌表型调节中的奉献者

基本信息

批准号：
8724068
负责人：
Shiyou Chen
金额：
$ 44.57万
依托单位：
UNIVERSITY OF GEORGIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-01 至 2018-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8724068
关键词：
Actins Angioplasty Animals Arterial Disorder Arteries Asthma Atherosclerosis Attenuated Binding Blood Vessels Bypass Cardiovascular Diseases Carotid Arteries Catheters Cell Nucleus Cell Proliferation Cell membrane Cells Contractile Proteins Cytokinesis Cytoskeleton Data Development Diabetes Mellitus Diabetic Angiopathies Disease Etiology Family Figs - dietary Focal Adhesions GKLF protein Genes Genetic Genetic Transcription Goals Guanine Nucleotide Exchange Factors Guanosine Triphosphate Phosphohydrolases Hematopoietic Hyperplasia Hypertension Injury Knock-out Knockout Mice Lead Ligation Lymphocyte Malignant Neoplasms Mediating Modeling Molecular Mus Pathologic Phenotype Physiological Play Process Rattus Role Serum Response Factor Smooth Muscle Smooth Muscle Actin Staining Method Smooth Muscle Myocytes Stenosis System Testing Therapeutic Agents Time Study Transcriptional Activation Transcriptional Regulation Transplantation United States Vascular Diseases Vascular Smooth Muscle Vascular remodeling Veins cell motility gain of function human disease in vivo insight loss of function mRNA Expression migration mortality mouse model myocardin neointima formation new therapeutic target novel overexpression platelet-derived growth factor BB promoter protein expression public health relevance restenosis rho small hairpin RNA therapeutic target

项目摘要

DESCRIPTION (provided by applicant): The overall goal of this proposal is to establish a novel mechanism by which dedicator of cytokinesis 2 (DOCK2) regulates the phenotypic modulation of vascular smooth muscle cells (SMC). Transition of SMC from a differentiated phenotype to a dedifferentiated state accompanied by neointima formation/vascular remodeling plays a critical role in the development of atherosclerosis, restenosis after angioplasty or bypass, diabetic vascular complications, transplantation arteriopathy, asthma, and cancer. The mechanisms and factors that regulate SMC phenotypic modulation and neointima formation, however, are poorly understood. Under physiological conditions, DOCK2 is only expressed in hematopoietic cells and controls lymphocyte migration and activation by regulating actin cytoskeleton through Rac activation. Our exciting preliminary data demonstrate that platelet derived growth factor (PDGF)-BB, a SMC phenotype modulator, induced DOCK2 expression in SMC. Knockdown of DOCK2 blocked PDGF-BB-induced SMC phenotypic modulation, proliferation, and migration. In vivo animal studies showed that DOCK2 was undetectable in SMC of normal rat carotid arteries, but was induced in the media layer SMC initially and neointimal SMC subsequently following balloon catheter-induced vascular injury. Importantly, knockdown of DOCK2 dramatically inhibited the injury- induced neointima formation. The most conclusive evidence for DOCK2-dependent vascular remodeling/ neointima formation was that knockout of DOCK2 (DOCK2-/-) dramatically blocked artery ligation-induced neointima hyperplasia in mouse carotid artery. Interestingly, DOCK2 is localized in both cell membrane and nuclei of SMC, suggesting that in addition to its role in cytoskeleton/cell migration, DOCK2 may be involved in SMC gene transcription. Indeed, DOCK2 overexpression blocked both SMC gene mRNA expression and myocardin-induced activation of smooth muscle ¿-actin promoter. Thus, the central hypothesis is that DOCK2 regulates SMC phenotypic modulation by suppressing SMC gene transcription and stimulating SMC migration/ proliferation, leading to neointima formation/vascular remodeling. Using primary culture of SMC, in vivo rat balloon injury and mouse wire injury models combining with molecular, cellular and histological approaches, we will 1) study the molecular mechanisms by which DOCK2 modulates SMC phenotype through regulating SMC gene transcription; 2) investigate if DOCK2 induces SMC migration through activation of Rac/RhoA/ Cdc42; and 3) determine the essential role of DOCK2 in SMC phenotypic modulation and vascular remodeling in vivo. The completion of this project will unravel a novel mechanism regulating SMC phenotypic modulation and provide novel insights into whether DOCK2 is a potential therapeutic target for countering vascular damage associated with common diseases including diabetes, restenosis, atherosclerosis, and cancer.

描述（由申请人提供）：该提案的总体目标是建立一种新的机制，通过该机制胞质分裂贡献者2（DOCK2）调节血管平滑肌细胞（SMC）的表型调节，使SMC从分化表型转变为非分化表型。伴随新内膜形成/血管重塑的去分化状态在动脉粥样硬化、血管成形术或搭桥术后再狭窄、糖尿病血管的发展中起着关键作用然而，在生理条件下，DOCK2 仅在造血细胞中表达，并通过调节肌动蛋白细胞骨架来控制淋巴细胞迁移和激活。我们令人兴奋的初步数据表明，SMC 表型调节剂血小板衍生生长因子 (PDGF)-BB 可诱导 SMC 中 DOCK2 的表达被阻断。 PDGF-BB诱导的SMC表型调节、增殖和迁移体内动物研究表明，DOCK2在正常大鼠颈动脉的SMC中检测不到，但最初在中层SMC中被诱导，随后在球囊导管诱导血管生成后在新内膜SMC中被诱导。重要的是，DOCK2 的敲除显着抑制了损伤诱导的新内膜形成。DOCK2 依赖性血管重塑/新内膜形成的最确凿的证据是敲除。 DOCK2 (DOCK2-/-) 显着阻断了参与 SMC 基因转录的小鼠颈动脉中动脉结扎诱导的新内膜增生。事实上，DOCK2 过表达可阻断 SMC 基因 mRNA 表达和心肌素诱导的平滑肌激活。因此，核心假设是 DOCK2 通过抑制 SMC 基因转录和刺激 SMC 迁移/增殖来调节 SMC 表型调节，从而导致新内膜形成/血管重塑。结合分子、细胞和组织学方法的损伤模型，我们将1）研究DOCK2通过调节SMC基因转录来调节SMC表型的分子机制；2）研究DOCK2是否诱导；通过激活 Rac/RhoA/Cdc42 实现 SMC 迁移；3) 确定 DOCK2 在体内 SMC 表型调节和血管重塑中的重要作用。 DOCK2是对抗与糖尿病、再狭窄、动脉粥样硬化和癌症等常见疾病相关的血管损伤的潜在治疗靶点。