HSC-derived fibroblasts in normal and diseased valves.

描述（由申请人提供）：使用单一造血干细胞（HSC）移植方法，采用源自小鼠的HSC，其广泛表达增强的绿色荧光蛋白，我们已经证明HSC产生成纤维细胞样细胞，其填充成人心脏瓣膜。我们将这种细胞群称为HSC衍生的瓣膜间质细胞（HVIC）。除了合成胶原蛋白外，我们对HVIC的功能知之甚少。本申请中概述的实验试图回答与生理和病理条件下HVIC的生物化学/生物合成和生长特性有关的基本问题。提出的实验将解决的总体假设是，移植正常HSC导致HVIC植入病变瓣膜可以改善瓣膜病变。有两个具体目标：第一个目的旨在确定：1）HVIC所代表的总瓣膜细胞的比例，2）其CD抗原、细胞因子（IL-β）和细胞因子受体表达谱是否将HVIC与其他常驻瓣膜细胞区分开来，3）一旦植入，细胞是否增殖或静止，以及4）HVIC是否是肌成纤维细胞的来源。此外，将研究HVIC对瓣膜损伤的生长和合成反应性。在第二个目标中，将评估HSC对瓣膜疾病的治疗潜力。为了实现这一点，我们将确定将来自正常小鼠的HSC移植到具有出生后瓣膜病变（即，粘液瘤性瓣膜病变和瓣膜脱垂）。这些研究将包括瓣膜功能的移植后评估（即，通过超声心动图和生物力学性质的测量）、组织学评估和转录组学分析以确定任何观察到的反应的遗传基础。

DESCRIPTION (provided by applicant): Using a single hematopoietic stem cell (HSC) transplantation approach employing HSCs derived from mice that ubiquitously express enhanced green fluorescent protein, we have shown that HSCs give rise to fibroblast-like cells that populate adult cardiac valves. We refer to this cell population as HSC-derived valve interstitial cells (HVICs). We know very little as to the function of HVICs other than they synthesize collagen. Experimentation outlined in this application seeks to answer fundamental questions pertaining to the biochemical/biosynthetic and growth characteristics of HVICs under both physiological and pathological conditions. An overarching hypothesis that will be addressed by the proposed experimentation is that transplantation of normal HSCs leading to engraftment of HVICs into diseased valves could ameliorate valvular pathologies. There are two specific Aims: The first Aim seeks to determine: 1) the proportion of total valve cells represented by HVICs, 2) whether their CD antigen, cytokine (ILI-beta) and cytokine receptor expression profile distinguishes HVICs from other resident valvular cells, 3) whether the cells are proliferative or quiescent once they engraft, and 4) whether HVICs are a source of myofibroblasts. In addition, the growth and synthetic responsiveness of HVICs to valvular injury will be studied. In the second Aim the therapeutic potential of HSCs to valvular disease will be assessed. To accomplish this, we will determine the consequence of transplanting HSCs from normal mice into mice having postnatal valve pathologies (i.e., myxomatous valve lesions and valve prolapse) induced by mutation in genes encoding the ECM proteins, periostin and fibrillin-1. These studies will include post-transplantation assessment of valve function (i.e., by echocardiography and measurement of biomechanical properties), histological assessment, and transcriptomic profiling to determine the genetic basis for any observed response.