Reprogramming of mature smooth muscle cells to vascular progenitor cells

成熟平滑肌细胞重编程为血管祖细胞

• 批准号: 8967222
• 负责人: Mary Cm. Weiser-Evans
• 金额: $ 54.69万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-15 至 2018-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8967222
• 关键词: Aneurysm; Animal Genetics; Arterial Injury; Atherosclerosis; Biological; Biological Assay; Blood Vessels; CD34 gene; Cell physiology; Cells; Contractile Proteins; Data; Development; Disease; Exhibits; Genetic; Genetic Models; Health; Hematopoietic stem cells; Heterogeneity; Homeostasis; In Situ; In Vitro; Inflammatory; Injury; Label; Lead; Lesion; MYH11 gene; Maintenance; Maps; Modeling; Molecular; Mus; PTEN gene; Pathway interactions; Phenotype; Play; Population; Process; Property; Proteins; Role; SHH gene; Signal Transduction; Smooth Muscle; Smooth Muscle Actin Staining Method; Smooth Muscle Myocytes; Source; Staging; Stem cells; Testing; Therapeutic; Tissues; Tumor Angiogenesis; Tumor Suppressor Proteins; Tunica Adventitia; Vascular Smooth Muscle; Wild Type Mouse; cell dedifferentiation; deep sequencing; genetic approach; improved; in vivo; innovation; loss of function; matrigel; monocyte; novel; osteogenic; overexpression; pluripotency; postnatal; progenitor; repaired; response; response to injury; restenosis; smoothened signaling pathway; stem; subcutaneous; transcription factor; transcriptome

DESCRIPTION (provided by applicant): Vascular smooth muscle cells (SMCs) are highly specialized cells that express high levels of SMC-specific proteins, such as smooth muscle myosin heavy chain (SMMHC/Myh11) and smooth muscle-�ctin (�A/Acta2)1. Under pathological conditions, however, SMCs are capable of undergoing profound phenotypic and functional changes resulting in a proliferative, inflammatory phenotype. An important paradigm shift in recent years suggests that vascular progenitor cells (VPCs) reside in a specialized niche within the adventitia of postnatal vessels. Adventitial VPCs express several stem cell markers, including Sca1 and CD34, have the capacity to differentiate in vitro into multiple lineages in response to specific signals, and potentially contribute to intimal lesions in vivo. However, important unanswered questions remain, including their origin, their degree of pluripotency and/or heterogeneity, and their contribution to vessel maintenance, repair, and pathological lesion formation. Using an innovative in vivo fate-mapping approach to genetically label mature Myh11- expressing SMC, we definitively established that mature SMCs give rise to the majority of intimal SMCs in response to wire-induced injury. Quite unexpectedly, we made the observation that some mature SMCs reverse migrate into the adventitia, exhibit no detectable expression of SM markers, but gain expression of Sca1 and CD34. We established that a distinct subpopulation of AdvSca1 progenitors arise from mature SMCs through a process we are calling "endogenous adventitial reprogramming" and suggest these cells play important roles in arterial homeostasis and disease. Our preliminary findings suggest SMC-derived AdvSca1 cells reside in the adventitia and contribute to a heterogeneic population of resident VPCs that possess distinct biological properties and fate decisions. Our overall hypothesis is that mature SMCs are reprogrammed during the later stages of vascular development to a subpopulation of functionally distinct VPCs; reprogramming is dependent at least in part on induction of the transcription factor, Klf4 and loss of the tumor suppressor, PTEN. After vascular injury, mobilization and recruitment of these cells contributes to intimal lesion formation and vessel repair. Our data could have a profound impact on defining the endogenous molecular mechanisms underlying the formation and maintenance of resident VPCs, which could lead to the potential to manipulate these cells in situ to improve therapeutic applications in settings suc as atherosclerosis/restenosis, aneurysm formation, ischemic tissues, and tumor angiogenesis. Mature macrovessel SMCs, as the source of resident VPCs, involving more than SMC dedifferentiation, but reprogramming to a functional progenitor phenotype, has not been described. Three Aims are proposed to define the differentiation potential and response of SMC- derived VPCs to vascular injury (Aim One), to define the role of Klf4 and PTEN on SMC reprogramming and identify essential endogenous pathways involved in SMC reprogramming (Aim Two), and define the in vivo fate and function of SMC-derived VPCs in response to vascular injury (Aim Three).

描述（申请人提供）：血管平滑肌细胞（SMC）是高度特化的细胞，表达高水平的SMC特异性蛋白，如平滑肌肌球蛋白重链（SMMHC/Myh 11）和平滑肌β-肌动蛋白（β A/Acta 2）1。然而，在病理条件下，SMC能够经历深刻的表型和功能变化，导致增殖性、炎性表型。近年来一个重要的范式转变表明，血管祖细胞（VPCs）居住在一个专门的生态位内的血管外膜出生后。外膜VPC表达几种干细胞标志物，包括Sca 1和CD 34，具有响应特定信号在体外分化成多个谱系的能力，并可能导致体内内膜病变。然而，重要的未回答的问题仍然存在，包括它们的起源，它们的多能性和/或异质性的程度，以及它们对血管维护，修复和病理性病变形成的贡献。使用一种创新的体内命运映射方法来遗传标记成熟的Myh 11表达SMC，我们明确地确定了成熟的SMC在对导丝诱导的损伤做出反应时产生了大多数内膜SMC。非常出乎意料的是，我们观察到一些成熟的SMC反向迁移到外膜中，没有显示出可检测的SM标记物表达，但获得Sca 1和CD 34的表达。我们建立了一个独特的AdvSca 1祖细胞亚群，通过我们称之为“内源性外膜重编程”的过程从成熟的SMC中产生，并表明这些细胞在动脉稳态和疾病中发挥重要作用。我们的初步研究结果表明，SMC衍生的AdvSca 1细胞存在于外膜中，并有助于形成具有不同生物学特性和命运决定的异质性VPC群体。我们的总体假设是，成熟的平滑肌细胞在血管发育的后期被重编程为功能不同的VPC亚群;重编程至少部分依赖于转录因子Klf 4的诱导和肿瘤抑制因子PTEN的缺失。血管损伤后，这些细胞的动员和募集有助于内膜损伤形成和血管修复。我们的数据可能会产生深远的影响，定义潜在的内源性分子机制的形成和维持的居民VPC，这可能会导致潜在的操纵这些细胞在原位，以改善治疗应用的设置，如动脉粥样硬化/再狭窄，动脉瘤形成，缺血组织，和肿瘤血管生成。成熟的大血管平滑肌细胞，作为常驻VPC的来源，涉及超过SMC去分化，但重编程为功能性祖细胞表型，尚未被描述。提出了三个目的，以定义SMC衍生的VPC的分化潜力和对血管损伤的响应（目的一），定义Klf 4和PTEN对SMC重编程的作用并识别参与SMC重编程的必要内源性途径（目的二），以及定义SMC衍生的VPC响应于血管损伤的体内命运和功能（目的三）。