Murine models of vascular remodeling

血管创伤修复受局部血管细胞与循环免疫和非免疫细胞之间的复杂相互作用控制。最近，对损伤的局部反应占主导地位的经典教条受到了循环血管祖细胞鉴定的挑战。这些血管祖细胞在血管再生中的作用及其与局部血管细胞和浸润免疫细胞的相互作用知之甚少。我的实验室已经采取了许多方法来了解这些细胞如何促进整体血管损伤反应，以及它们最终如何被治疗操纵。 我们研究了动脉损伤后立即发生的事件，并确定了中膜VSMC产生的RANTES的急性STAT 3和NF-B（p65亚基）依赖性上调，导致早期T细胞和巨噬细胞募集-也是在p21 Cip 1的高阶调节下进行的过程。VSMC特有的是，RANTES的产生由TNF而不是IL-6/gp 130启动，并且依赖于p65-STAT 3复合物与RANTES启动子内的NF-B结合位点的结合，而STAT 3或p65的shRNA敲低显著减弱RANTES的产生。在体内，中膜VSMC中的急性NF-B和STAT 3活化被鉴定，与对照组相比，TNF-/-小鼠损伤后的急性RANTES产生显著减少。最后，我们产生了平滑肌细胞特异性条件性STAT 3敲除小鼠（STAT 3fl/fl; SM 22-Cre），并证实了VSMC急性RANTES产生的STAT 3依赖性。总之，这些观察结果统一了血管损伤后的炎症事件，表明VSMC通过急性RANTES产生和随后的炎症细胞募集协调动脉炎症反应程序。 移植到动脉环境中的静脉经历血管重塑，这是一个具有重要临床意义的复杂过程。使用谱系追踪实验，我们提供了前所未有的证据表明，来自静脉移植物的内皮细胞有助于间充质细胞;在新生内膜形成过程中。在移植到股动脉的小鼠颈静脉中，我们发现内皮细胞失去了它们的新生标志物，并随着时间的推移获得平滑肌细胞标志物，这表明内皮细胞向间质细胞转化（EndoMT）。该过程依赖于TGF-β信号传导，具有早期Smad激活。TGF-中和抗体、siRNA介导的Smad 3敲低或Smad 3单倍不足对TGF-信号传导的拮抗作用导致EndoMT减少和有利的血管重塑。因此，我们已经将EndoMT确定为静脉移植物狭窄产生新生内膜过度生长的一种新的关键机制，这意味着潜在的预防静脉移植物病理学的新治疗靶点。

Vascular wound repair is controlled by a complex interaction between local vascular cells and circulating immune and non-immune cells. Recently, the classic dogma of a predominantly local response to injury has been challenged by the identification of circulating vascular progenitor cells. The role of these vascular progenitor cells in vascular regeneration and their interaction with local vascular cells and infiltrating immune cells is poorly understood. My laboratory has undertaken a number of approaches to understand how these cells contribute to the overall vascular injury response and how they might ultimately be therapeutically manipulated. We studied events immediately following arterial injury and identified an acute STAT3- and NF-B (p65 subunit)-dependent upregulation of RANTES production by medial VSMCs, leading to early T cell and macrophage recruitment - processes also under the higher-order regulation of p21Cip1. Unique to VSMCs, RANTES production was initiated by TNF but not IL-6/gp130, and was dependent on binding of a p65-STAT3 complex to NF-B binding sites within the RANTES promoter, with shRNA knockdown of either STAT3 or p65 markedly attenuating RANTES production. In vivo, acute NF-B and STAT3 activation in medial VSMCs was identified, with acute RANTES production after injury significantly reduced in TNF-/- mice compared to controls. Finally, we generated mice with smooth muscle cell-specific conditional STAT3 knockout (STAT3fl/fl;SM22-Cre) and confirmed the STAT3-dependence of acute RANTES production by VSMCs. Together, these observations unify inflammatory events after vascular injury, demonstrating that VSMCs orchestrate the arterial inflammatory response program via acute RANTES production and subsequent inflammatory cell recruitment. Veins grafted into an arterial environment undergo vascular remodeling, a complex process of major clinical importance. Using lineage tracing experiments, we provide unprecedented evidence that cells of endothelial origin from the vein graft contribute to mesenchymal cellularity; during neointimal formation. In murine jugular veins grafted to femoral arteries, we found that endothelial cells lose their nascent markers and over time gain smooth muscle cell markers, indicative of endothelial to mesenchymal transition (EndoMT). This process is dependent on TGF- signaling, with early Smad activation. Antagonism of TGF- signaling by TGF- neutralizing antibody, siRNA-mediated Smad3 knockdown, or Smad3 haploinsufficiency resulted in decreased EndoMT and favorable vascular remodeling. Hence, we have identified EndoMT as a novel and pivotal mechanism underlying the stenosis-producing neointimal overgrowth of vein grafts, implying a potential a new therapeutic target to prevent vein graft pathology.