Wnt Signaling in Stroke

项目摘要 卒中中的WNT信号 脑出血(ICH)是最致命但研究不足的中风类型。治疗靶点为 最大限度地减少病理过程，侧重于减轻炎症和促进血肿清除。WNT 在某些情况下，信号调节多种细胞活动，并调节小胶质细胞的炎症反应 脑部疾病。尽管许多工作已经研究了Wnt依赖的细胞发生，但与 就我们对Wnt信号如何调节脑出血后炎症反应的理解而言。隐秘的 卷曲相关蛋白3(sFRP3，Frzb的同义词)调节规范和非规范的Wnt途径， 而sFRP3的调节失调与某些病理条件有关，包括骨关节炎、星形细胞瘤、 和心力衰竭。然而，很少有研究研究sFRP3在大脑中的作用，目前对此也知之甚少 SFRP3/Wnt信号在卒中或脑出血损伤中的作用R01的科学目标是研究 星形胶质细胞sFRP3是否抑制促炎反应，从而减轻急性脑出血损伤并改善 功能结果。通过使用多种细胞、分子、遗传、药理学、组织学和流程 细胞计量学方法，我们已经获得了强有力的证据表明sFRP3在保护 早期脑出血损伤：1)脑出血后早期血肿周围星形胶质细胞sFRP3表达上调 ICH；2)sFRP3功能的丧失/获得加剧/减轻脑出血损伤；以及3)sFRP3缺失增加 Toll样受体(TLR)4和Wnt下游分子RhoA的表达及基质金属蛋白酶-9活性 我有脑子。这些新奇的观察结果支持了星形胶质细胞sFRP3预防早衰的科学前提。 ICH损伤，并导致我们假设星形胶质细胞sFRP3通过抑制促进小胶质细胞M2极化 星形胶质细胞sFRP3通过TLR4/WNT信号通路减轻脑出血后的脑损伤。在……里面 三个具体目标，我们将确定sFRP3功能的丧失/获得是否加剧/减轻脑出血损伤(AIM 1)，星形胶质细胞sFRP3是否通过抑制TLR4信号促进小胶质细胞M2极化(目标2)， 星形胶质细胞sFRP3是否通过TLR4/Wnt信号通路减轻脑损伤(目标3)。vbl.使用 多学科方法，本研究将阐明星形胶质细胞sFRP3在脑出血后的作用以及细胞和 星形胶质细胞sFRP3介导的小胶质细胞表型转换减轻灰质和脑缺血的分子机制 损伤脑白质，促进功能恢复。这部新奇的概念验证作品具有翻译潜力 并将刺激更多关于sFRP3在各种脑部疾病中的研究。研究中风后的先天免疫 NINDS-SPRG最近确定的一个关键优先事项。

Project Summary Wnt signaling in stroke Intracerebral hemorrhage (ICH) is the most lethal but under-researched type of stroke. Therapeutic targets to minimize pathologic processes focus on mitigating inflammation and promoting hematoma clearance. Wnt signaling regulates diverse cellular activities and modulates an inflammatory response in microglia in certain brain diseases. Although much work has investigated Wnt-dependent cell genesis, a critical gap exists with respect to our understanding of how Wnt signaling regulates inflammatory responses after ICH. The secreted frizzled-related protein 3 (sFRP3, a synonym of Frzb) regulates both canonical and noncanonical Wnt pathways, and dysregulation of sFRP3 is associated with certain pathologic conditions, including osteoarthritis, astrocytoma, and heart failure. However, very few studies have investigated sFRP3 in brain, and little is currently known about the role of sFRP3/Wnt signaling in injury from stroke or ICH. The scientific objective of this R01 is to investigate whether astrocyte sFRP3 inhibits proinflammatory response, thereby reducing acute ICH injury and improving functional outcomes. By using multiple cellular, molecular, genetic, pharmacologic, histologic, and flow cytometric methods, we have obtained strong evidence to suggest a key role for sFRP3 in protection against early ICH injury: 1) sFRP3 expression level is upregulated in astrocytes in the perihematomal region early after ICH; 2) Loss/gain of sFRP3 function exacerbates/mitigates ICH injury; and 3) sFRP3 deletion increases expression of Toll-like receptor (TLR)4 and Wnt downstream molecule RhoA, as well as MMP-9 activity in the ICH brain. These novel observations support the scientific premise that astrocyte sFRP3 protects against early ICH injury and led us to hypothesize that astrocyte sFRP3 promotes microglial M2 polarization through inhibition of TLR4 signaling and that astrocyte sFRP3 attenuates brain damage through TLR4/Wnt signaling after ICH. In three specific aims, we will determine whether loss/gain of sFRP3 function exacerbates/mitigates ICH injury (Aim 1), whether astrocyte sFRP3 promotes microglial M2 polarization through inhibition of TLR4 signaling (Aim 2), and whether astrocyte sFRP3 attenuates brain injury through the TLR4/Wnt signaling pathway (Aim 3). Using multidisciplinary approaches, this study will elucidate the role of astrocyte sFRP3 after ICH and the cellular and molecular mechanisms by which astrocyte sFRP3-mediated microglial phenotypic switching mitigates gray and white matter injury, and improves functional recovery. This novel proof-of-concept work has translational potential and will stimulate more studies of sFRP3 in various brain diseases. Investigating innate immunity after stroke is a critical priority identified by the recent NINDS-SPRG.