Mechanisms of Th2 interleukin-driven angiogenesis

描述（由申请人提供）：本申请的总体目标是证明白细胞介素-19 (IL-19)，一种抗炎的Th2白介素，可以促进血管生成和改善缺血组织的灌注。IL-19是一种新发现的Th2 （T调节性）抗炎白介素，在我们的研究之前，它一直被认为是炎症细胞特异性的。我们仍然是唯一一个研究这种白细胞介素在血管生物学中的作用的实验室，特别是在EC和VSMC病理生理方面。炎症和抗炎细胞因子都参与伤口愈合和新血管形成，但抗炎细胞因子在血管生成中的作用以及这些过程之间的相互作用尚不清楚。与我们之前的研究表明IL-19抑制血管平滑肌细胞（VSMC）的迁移和增殖相反，我们最近报道了令人惊讶的发现，IL-19对人内皮细胞（EC）具有强大的促血管生成作用。IL-19在正常EC中未检测到，但在人血管生成组织的毛细血管中表达。IL-19对EC有丝分裂和趋化作用，促进细胞扩散，激活MAPK和Rac1。IL-19促进体内主动脉环和pecam1阳性微血管的形成。IL-19可诱导EC血管生成基因的表达。IL-19的作用不依赖于VEGF和bFGF，两者都不能诱导IL-19的表达，IL-19也不能诱导两者的表达。中和bFGF和VEGF不影响IL-19活性，提示th2诱导的新途径刺激EC活化和血管生成。IL-19可使人巨噬细胞向M2“创面愈合”表型极化，诱导巨噬细胞血管生成基因表达。IL-19的表达和功能与促炎抗血管生成细胞因子IL-12相互作用并调节。这些初步和已发表的数据支持了IL-19是一种具有多种效应细胞的新型血管生成细胞因子的假设。IL-19是否能恢复缺血组织的血流，主要的效应细胞是内皮细胞还是M2巨噬细胞，有哪些可溶性因子介导IL-19的作用，IL-19在EC和VSMC中差异作用的分子机制和介质有待确定。我们将确定IL-19的缺失是否会减弱，IL-19的过表达是否会促进血管生成并恢复缺血组织中的血流，IL-19对血管生成的调节是否通过直接作用于血管细胞或通过巨噬细胞M2极化来促进，将识别和表征IL-19驱动血管生成所需的IL-19诱导因子。并验证IL-20受体亚基的差异表达解释了IL-19在VSMC中与EC相比的多效性效应的假设。这一应用可能会改变范式，因为它将涉及Th2白细胞介素作为一种新的抗炎、促血管生成的细胞因子，由炎症的常驻血管细胞表达，以促进新血管的形成。

DESCRIPTION (provided by applicant): The overall goal of this application is to demonstrate that Interleukin-19 (IL-19), an anti-inflammatory, Th2 interleukin, can drive angiogenesis and improve perfusion of ischemic tissue. IL-19 is a newly described Th2, (T regulatory) anti-inflammatory interleukin which until our work, had been ascribed to be inflammatory cell-specific. We remain the only laboratory to investigate a role for this Interleukin in vascular biology, particularly with respect to EC and VSMC pathophysiology. Both inflammatory and anti- inflammatory cytokines participate in wound healing and neo-vascularization, but the role of anti- inflammatory cytokines in angiogenesis and the cross-talk between these processes remain under characterized. In contrast to our previous work indicating that IL-19 suppresses vascular smooth muscle cells (VSMC) migration and proliferation, we have recently reported the surprising finding that IL-19 has potent pro-angiogenic effects on human endothelial cells (EC). IL-19 is not detected in normal EC but is expressed in EC in capillaries in human angiogenic tissue. IL-19 is mitogenic and chemotactic for EC, promotes cell spreading, and activates MAPK and Rac1. IL-19 promotes microvessel formation in aortic rings, and PECAM1-positive microvessels in vivo. IL-19 can induce angiogenic gene expression in EC. IL-19 effects are independent of VEGF and bFGF, as neither can induce IL-19 expression, and IL-19 cannot induce expression of either. Neutralization of bFGF and VEGF does not affect IL-19 activity, suggesting a novel, Th2-induced pathway to stimulate EC activation and angiogenesis. IL-19 can polarize human macrophage to the M2, "wound healing" phenotype, and induce angiogenic gene expression in macrophage. IL-19 expression and function is reciprocal to and regulates the pro- inflammatory anti-angiogenic cytokine IL-12. These preliminary and published data have driven the hypothesis that IL-19 is a novel vasculogenic cytokine with multiple effector cells. What needs to be determined is if IL-19 can restore blood flow in ischemic tissue, if the major effector cell is endothelial cells or the M2 macrophage, what soluble factors mediate IL-19 effects, and the molecular mechanisms and mediators of IL-19 differential effects in EC and VSMC. We will determine if absence of IL-19 attenuates, and if over expression of IL-19 promotes angiogenesis and restores blood flow in ischemic tissue, if IL-19 regulation of angiogenesis is facilitated by direct effects on vascular cells, or by macrophage M2 polarization, will identify and characterize IL-19 inducible factors necessary for IL-19- driven angiogenesis in vivo, and test the hypothesis that differential expression of IL-20 receptor subunits account for pleiotropic effects of IL-19 in VSMC compared with EC. This application is potentially paradigm-changing as it will implicate a Th2 interleukin as a novel anti-inflammatory, pro-vasculogenic cytokine expressed by inflamed resident vascular cells to promote neovascularization.