Role of Lung MSC in Emphysema

慢性阻塞性肺疾病(COPD)是美国第三大致死原因 各州。慢性阻塞性肺疾病通常会因血管病变而加重，这会严重恶化预后并限制生存。 血管病变的特征是微血管重塑和丢失。最近的证据也突显了一个 微血管改变在COPD早期发病机制及异质性中的作用 尽管潜在的机制还没有定义。这项提案的目标是解决这一知识 通过确定相互间充质祖细胞-内皮细胞之间的分子机制来实现GAP 相互作用调节肺微血管结构和COPD的发生发展。在上一笔资金中 周期中，我们报道了一种新的间充质祖细胞(MPC)群体的存在，这种细胞群起着 周细胞的祖细胞，因此需要维持微血管的动态平衡。我们进一步 据报道，Wnt/β-catenin信号转导通路是该MPC功能的重要调节因子。然而，如何 MPC中Wnt信号的增加及其调节因子Dkk1的产生与血管病变的发生 撞击表面进行气体交换，COPD的病理生理机制尚不清楚。因此，理解 WNT信号在MPC中，对促进微血管和组织功能将是重要的。小说的前提是 这一建议认为，MPC内增强的Wnt/β-连环蛋白信号间接导致肺气肿和慢性阻塞性肺疾病 通过改变正常的MPC-微血管内皮细胞(MVEC)相互作用。我们假设激活 MPC中Wnt/β-catenin通过1)增加Dkk1和b)a的产生而加重慢性阻塞性肺疾病的发病 Dkk1对微血管内皮细胞功能的旁分泌作用我们将测试WNT/β的激活- MPC中的连环蛋白通过增加Dkk1的MPC表达和随后的旁分泌改变而导致COPD 微血管内皮细胞命运规范。检测β-连环蛋白和DKK1的丝裂原蛋白表达是否 对于COPD患者MPC-MVEC串扰和组织重塑的维持至关重要，我们将有条件地敲打 在巨噬细胞中下调或过表达DKK1和β-连环蛋白，并使小鼠暴露于吸烟或血管损伤。我们将聘用 谱系分析、光学相干断层扫描(OCT)、血管生成的组织学指标的新模型 以及屏障功能的度量。我们还将通过以下方式测试MPC-MVEC交互的维护 调控Dkk1信号转导通路可减轻脑缺血后微血管功能和组织结构的损伤 受伤。我们将在体外操纵人和小鼠肺MPC中的Dkk1/Wnt信号并抑制Dkk1 在小鼠体内模型中的信号转导，以评估MVEC功能受影响的机制。这些 研究将确定在MVEC中调制MPC或抑制/敲除Dkk1信号是否可行 目的促进微血管功能，减轻慢性阻塞性肺疾病。我们建议的研究将推动 通过定义Wnt依赖的MPC调节微血管内皮细胞功能的机制并鉴定 通过改变FDA批准的Dkk1调节剂的用途来逆转COPD患者的血管病变。

Chronic obstructive pulmonary disease (COPD) is the third leading cause of mortality in the United States. COPD often is exacerbated by vasculopathy, which substantially worsens prognosis and limits survival. Vasculopathy is characterized by remodeling and loss of microvessels. Recent evidence has also highlighted a role for the alterations to the microvasculature during the early pathogenesis and heterogeneity of COPD, although the underlying mechanisms are not defined. The goal of this proposal is to address this knowledge gap by defining the molecular mechanisms whereby reciprocal mesenchymal progenitor-endothelial cell interactions regulate pulmonary microvascular structure and the development of COPD. In the last funding cycle, we reported the existence of a novel population of mesenchymal progenitor cells (MPC) which serve as progenitors for pericytes and therefore are required to maintain microvascular homeostasis. We further reported that Wnt/β-catenin signaling was an important regulator of this MPC function. However, how increased Wnt signaling in MPC, production of its modulator Dkk1 and the development of vasculopathy impacts surfaces for gas exchange and the pathophysiology of COPD is unknown. Therefore, understanding Wnt signaling in MPC, will be important to facilitate microvascular and tissue function. The novel premise of this proposal is that enhanced Wnt/β-catenin signaling within MPCs indirectly leads to emphysema and COPD by altering normal MPC-microvascular endothelial cell (MVEC) interactions. We hypothesize that activation of Wnt/β-catenin in MPC exacerbates the onset of COPD via 1) increased production of Dkk1 and b) a paracrine effect of Dkk1 on microvascular endothelial cell function. We will test that activation of Wnt/β- catenin in MPCs leads to COPD via increased MPC expression of Dkk1 and subsequent paracrine alteration of microvascular endothelial cell-fate specification. To test whether MPC expression of β-catenin and Dkk1 are critical for maintenance of MPC-MVEC cross talk and tissue remodeling in COPD, we will conditionally knock down or overexpress Dkk1 and β-catenin in MPC and expose mice to smoke or vascular injury. We will employ novel models of lineage analyses, optical coherence tomography (OCT), histological indices of angiogenesis and measures of barrier function. We will also test that maintenance of MPC-MVEC interaction via manipulation of Dkk1 signaling will attenuate loss of microvascular function and tissue structure following injury. We will manipulate Dkk1/Wnt signaling in human and mouse lung MPCs in vitro and inhibit Dkk1 signaling in murine models in vivo, to evaluate the mechanism by which MVEC function is affected. These studies will determine whether modulation of MPC, or inhibition / knockout Dkk1 signaling in MVEC is a viable target to promote microvascular function and attenuate COPD. Our proposed studies will advance the field of by defining Wnt dependent mechanisms by which MPC regulate microvascular endothelial function and identify targets to reverse vasculopathy in COPD, by repurposing of FDA approved DKK1 modulators.