CXCR4-dependent tissue remodeling after experimental stroke

实验性卒中后CXCR4依赖性组织重塑

• 批准号: 25228946
• 负责人: Professor Dr. Ralf Stumm
• 金额: --
• 依托单位: Institut für Pharmakologie und Toxikologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/25228946?language=en
• 关键词: CXCR4; dependent; tissue; remodeling; after

CXCR4 chemokine receptors are expressed in hematopoietic and neural stem cells. The receptor guides migration of leukocytes and precursor cells that are derived from these stem cells. Consistently, a CXCR4 antagonist (plerixafor, AMD3100) was recently approved for hematopoietic stem cell mobilization. Functions of CXCR4 in neoplastic, inflammatory and regenerative processes are intensively investigated. In this context, it was reported that the CXCR4-mediated signal of the chemokine CXCL12 directs stem cells and inflammatory cells towards lesioned tissues. Accordingly, CXCR4 is thought to be involved in tissue remodeling, neovascularization and tumor formation. However, proper investigation of these processes requires non-ambiguous identification of tissues that develop from Cxcr4-expressing stem cells. In addition, controllable inactivation of CXCR4 is desirable. Since CXCL12- and CXCR4-deficient mice die perinatally, a conditional approach is necessary. The applicant thus generated mice harboring a Cxcr4-knockout/CreER-knockin allele (Cxcr4CreER) and an established Cre-reporter. In these mice, tamoxifen induces permanent expression of the fluorescent protein TdTomato in cells with an active Cxcr4 promoter. When the Cxcr4CreER allele is combined with a Cxcr4LoxP allele, Cxcr4-CreER permits Cxcr4 ablation. Thorough characterization of Cxcr4CreER/WT and Cxcr4CreER/LoxP mice showed that analysis of TdTomato-positive cells permits to trace the lineage of Cxcr4-expressing stem cells in the presence (Cxcr4CreER/WT) and in the absence (Cxcr4CreER/LoxP) of functional CXCR4. The applicant plans to use this model to assess the function of CXCR4 in remodeling processes after experimental stroke (recruitment of monocytes, neutrophils and immature neurons, glial reaction and neovascularization in the lesioned area). In the second focus, stem cells will be in vivo-labeled with Cxcr4-CreER, isolated and characterized during in vitro propagation and reimplantation. The project will shed light on the question if CXCR4 is a suitable drug target in stroke and rigorously test the concept that CXCR4 directs stem cells during remodeling of ischemic lesions.

CXCR 4趋化因子受体在造血和神经干细胞中表达。该受体引导白细胞和来源于这些干细胞的前体细胞的迁移。同样，CXCR 4拮抗剂（普乐沙福，AMD 3100）最近被批准用于造血干细胞动员。CXCR 4在肿瘤、炎症和再生过程中的功能被深入研究。在此背景下，据报道趋化因子CXCL 12的CXCR 4介导的信号将干细胞和炎性细胞导向病变组织。因此，CXCR 4被认为参与组织重塑、新血管形成和肿瘤形成。然而，这些过程的适当调查需要明确鉴定从Cxcr 4表达干细胞发育的组织。此外，CXCR 4的可控失活是期望的。由于CXCL 12和CXCR 4缺陷小鼠围产期死亡，有条件的方法是必要的。 因此，申请人产生了携带Cxcr 4敲除/CreER敲入等位基因（Cxcr 4CreER）和已建立的Cre-reporter的小鼠。在这些小鼠中，他莫昔芬诱导具有活性Cxcr 4启动子的细胞中荧光蛋白TdTomato的永久表达。当Cxcr 4CreER等位基因与Cxcr 4LoxP等位基因组合时，Cxcr 4-CreER允许Cxcr 4消融。Cxcr 4CreER/WT和Cxcr 4CreER/LoxP小鼠的彻底表征显示，TdTomato阳性细胞的分析允许在存在（Cxcr 4CreER/WT）和不存在（Cxcr 4CreER/LoxP）功能性CXCR 4的情况下追踪表达Cxcr 4的干细胞的谱系。申请人计划使用该模型评估CXCR 4在实验性卒中后重塑过程中的功能（单核细胞、中性粒细胞和未成熟神经元的募集，病变区域的神经胶质反应和新血管形成）。在第二个焦点中，干细胞将在体外增殖和再植入期间用Cxcr 4-CreER进行体内标记、分离和表征。该项目将阐明CXCR 4是否是中风中合适的药物靶点，并严格测试CXCR 4在缺血性病变重塑期间指导干细胞的概念。