Microenvironmental Endogenous Reprogramming of Differentiated Smooth Muscle Cells

分化平滑肌细胞的微环境内源性重编程

• 批准号: 8451768
• 负责人: Mary Cm. Weiser-Evans
• 金额: $ 22.06万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8451768
• 关键词: Adult; Aorta; Arterial Injury; Arterial Medias; Atherosclerosis; Blood Vessels; CD34 gene; Cardiovascular system; Cell Shape; Cells; Characteristics; Clinical; Contractile Proteins; Contracts; Data; Development; Endothelial Cells; Exhibits; Fibroblasts; Genetic; Hematopoietic stem cells; In Vitro; Inflammatory; Injury; Label; Lead; Lesion; Maintenance; Maps; Medicine; Molecular; Mus; Muscle Cells; Myosin Heavy Chains; Phenotype; Population; Production; Proteins; Regenerative Medicine; Research; Role; Serum; Signal Transduction; Smooth Muscle; Smooth Muscle Actin Staining Method; Smooth Muscle Myocytes; Smooth Muscle Myosins; Somatic Cell; Source; Staging; Stem cells; Technology; Therapeutic; Therapeutic Uses; Tunica Adventitia; Vascular Diseases; Wild Type Mouse; base; cell dedifferentiation; cytokine; defined contribution; improved; in vivo; innovation; macrophage; neointima formation; osteogenic; postnatal; progenitor; public health relevance; repaired; response; restenosis; self-renewal; smoothened signaling pathway; stem; theories; transcription factor

DESCRIPTION (provided by applicant): Vascular smooth muscle cells (SMCs) are highly specialized cells that contract to maintain vascular tone, are quiescent and express high levels of SMC-specific proteins, such as smooth muscle myosin heavy chain (SMMHC). Under pathological conditions, however SMCs are capable of undergoing profound phenotypic and functional changes making them major contributors to pathological neointima formation. An important paradigm shift in recent years suggests that vascular progenitor cells (VPCs) with the capacity to differentiate into SMCs and endothelial cells reside in a specialized niche within the adventitia of postnatal vessels. While emerging data support the existence of adventitial VPCs, important unanswered questions remain, including their origin and their contribution to vessel maintenance, repair, and pathological lesion formation. Using an innovative in vivo fate-mapping approach, we made the unanticipated observation that mature SMCs migrate into the adventitia, downregulate SM marker expression, and gain expression of progenitor cell markers. Our preliminary findings demonstrate that a population of SMC-derived Sca1(+) cells can be isolated from adult vessels that express a functional progenitor cell phenotype and exhibit the capacity to differentiate into SMCs. A small percentage retained expression of Sca1, indicating the potential for self-renewal. Our findings suggest the emergence of resident VPCs from reprogrammed mature SMCs. Our overall hypothesis is that mature SMCs migrate to the adventitia during the later stages of vascular development and are reprogrammed to VPCs in response to specific signals expressed exclusively in the adventitia (e.g. microenvironmental reprogramming); reprogramming is dependent on induction on the transcription factor, Klf4. After vascular injury, recruitment of these cells contributes to neointima formation. Such a finding could have a profound impact on defining the molecular mechanisms underlying the formation and maintenance of VPCs and could lead to advances in our understanding of somatic cell reprogramming to improve clinical therapeutic applications. Mature SMCs as the source of resident VPCs is an anti-dogmatic theory that would challenge existing concepts. Two Aims are proposed to establish the importance and the role of SMC-derived AdvSca1 cells in normal vessels and in the setting of vascular injury. In Aim One, we will characterize and define the contribution of mature SMC to the adventitial VPC pool, we will define the in vitro functional characteristics of SMC-derived VPCs, and we will define the in vitro and in vivo role of Klf4 on SMC reprogramming. For Aim Two, we will determine the fate of SMC-derived VPCs in response to wire-induced vascular injury.

描述（由申请人提供）：血管平滑肌细胞（SMCs）是高度特化的细胞，其收缩以维持血管张力，处于静止状态并表达高水平的smc特异性蛋白，如平滑肌肌球蛋白重链（SMMHC）。然而，在病理条件下，SMCs能够经历深刻的表型和功能变化，使其成为病理性新内膜形成的主要贡献者。近年来一个重要的范式转变表明，血管祖细胞（VPCs）具有分化为SMCs和内皮细胞的能力，存在于出生后血管外膜内的一个特殊生态位中。虽然新出现的数据支持外源性VPCs的存在，但仍存在一些重要的未解之谜，包括它们的起源及其对血管维护、修复和病理病变形成的贡献。使用一种创新的体内命运定位方法，我们进行了意想不到的观察，成熟的SMCs迁移到外膜，下调SM标记的表达，并获得祖细胞标记的表达。我们的初步研究结果表明，smc衍生的Sca1（+）细胞群体可以从成年血管中分离出来，表达功能性祖细胞表型，并表现出向smc分化的能力。一小部分保留了Sca1的表达，表明有自我更新的潜力。我们的研究结果表明，从重编程的成熟SMCs中出现了常驻VPCs。我们的总体假设是，成熟的SMCs在血管发育的后期阶段迁移到外膜，并根据外膜中表达的特定信号（如微环境重编程）被重编程为VPCs；重编程依赖于转录因子Klf4的诱导。在血管损伤后，这些细胞的募集有助于新内膜的形成。这一发现可能对定义VPCs形成和维持的分子机制产生深远的影响，并可能导致我们对体细胞重编程的理解取得进展，以改善临床治疗应用。成熟的中小型企业作为常驻vpc的来源是一个反教条的理论，将挑战现有的概念。我们提出了两个目的来确定smc来源的AdvSca1细胞在正常血管和血管损伤中的重要性和作用。在Aim 1中，我们将描述和定义成熟SMC对外来VPC池的贡献，我们将定义SMC衍生的VPC的体外功能特征，我们将定义Klf4在SMC重编程中的体外和体内作用。在第二阶段，我们将确定smc衍生的VPCs在钢丝诱导的血管损伤中的命运。