Inflammatory modulation of CXCL12 expressing niche cells in bone marrow

项目摘要 与感染相关的急性炎症信号导致HSC增殖，从而产生大量HSC。 免疫效应细胞。然而，更严重和更长时间的炎症与骨髓有关 失败状态，例如骨髓移植后的并发症。传染性和非传染性 炎症信号影响HSC稳态。这种作用可以直接在HSC上介导，也可以通过 小生境细胞表达CXCL 12的小生境细胞代表了形成不同小生境的重要小生境细胞群 其支持造血干细胞和/或祖细胞。利用互补的新成像方法， 通过对骨髓腔的二维和三维分析，我们发现， TNF-α和/或脂多糖（LPS）迅速减少表达CXCL 12的小生境细胞的数量， 在1-4小时内引起小生境细胞胞质结构的缺陷。我们建议理解如何 炎症信号调节HSCP龛细胞可能暗示龛细胞在以下疾病中的致病作用： 与移植前后环境中的炎症相关的造血功能障碍。在目标1中， 描述炎症对CXCL 12-niche细胞数量和/或生长因子表达的影响， 特异性表达CXCL 12的小生境细胞群。分析将在不同的时间间隔进行 TNF-α、LPS.在目标2中，表达CXCL 12的龛细胞的动态变化 细胞质结构将在不同的时间间隔通过三个互补的 成像技术。动态结构变化将与BM中的造血细胞构成相关， 进入循环。在目的3中，我们将检测LPS和TNF-α是否介导它们对 在一些实施方案中，本发明涉及直接或间接（例如通过首先作用于造血细胞，如巨噬细胞）促进造血的方法。本 最后，4只单独的重建嵌合小鼠，其中造血区室/骨髓 在一些实施方案中，将产生WT或TNFR/TLR 4缺陷的微环境。我们建议， 炎症应激后基质细胞和HSPC之间的动态关系可能导致新的 骨髓功能障碍状态下造血再生的治疗方法- 需要大量血液制品支持的移植环境。

PROJECT SUMMARY Acute inflammatory signals associated with infection lead to HSC proliferation thus generating large numbers of immune effector cells. However, more severe and prolonged inflammation has been linked to bone marrow failure states, e.g. complications following bone marrow transplantation. Infectious as well as non-infectious inflammatory signals affect HSC homeostasis. Such effects can be mediated directly on HSC or indirectly via niche cells. CXCL12-expressing niche cells represent an important niche cell population forming distinct niches that support hematopoietic stem and/or progenitor cells. Utilizing complementary novel imaging approaches for 2D and 3D analysis of the bone marrow cavity, we show that inflammatory stress following administration of TNF-α and/or lipopolysaccharide (LPS) rapidly reduces the number of CXCL12 expressing niche cells and causes defects in niche cell cytoplasmic structure within 1-4 hours. We propose that understanding how inflammatory signals modulate HSCP niche cells may implicate a pathogenic role of niche cells in disorders of dysfunctional hematopoiesis associated with inflammation in the peri-transplant setting. In Aim 1 we will delineate the consequences of inflammation on CXCL12-niche cell number and/or growth factor expression in specific CXCL12 expressing niche cell populations. The analyses will be done at various time intervals following administration of TNF-α, LPS. In aim 2, the dynamic alterations in CXCL12 expressing niche cell cytoplasmic structure will be visualized and quantified at different time intervals by three complementary imaging techniques. The dynamic structural changes will be correlated with hematopoietic cellularity in BM and egress into the circulation. In aim 3, we will examine whether LPS and TNF-α mediate their effect on hematopoiesis directly or indirectly (e.g. by acting first on hematopoietic cells such as macrophages). To this end, 4 separate reconstituted chimeric mice in which the hematopoietic compartment/bone marrow microenvironment is either WT or deficient in TNFR/TLR4, will be generated. We propose that understanding the dynamic relationship between stromal cells and HSPC following inflammatory stress may lead to new therapeutic approaches for hematopoietic regeneration in bone marrow dysfunction states in the peri- transplant setting, which require significant blood product support.