The fate of hematopoietic stem and progenitor cells (HSPCs) is regulated by their interaction with stromal cells in the bone marrow. However, the cellular mechanisms regulating HSPC interaction with these cells and their potential impact on HSPC polarity are still poorly understood. Here we evaluated the impact of cell–cell contacts with osteoblasts or endothelial cells on the polarity of HSPC. We found that an HSPC can form a discrete contact site that leads to the extensive polarization of its cytoskeleton architecture. Notably, the centrosome was located in proximity to the contact site. The capacity of HSPCs to polarize in contact with stromal cells of the bone marrow appeared to be specific, as it was not observed in primary lymphoid or myeloid cells or in HSPCs in contact with skin fibroblasts. The receptors ICAM, VCAM, and SDF1 were identified in the polarizing contact. Only SDF1 was independently capable of inducing the polarization of the centrosome–microtubule network.

中文翻译：

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造血祖细胞在与骨髓基质细胞接触时响应 SDF1 极化

造血干细胞和祖细胞 (HSPC) 的命运是通过它们与骨髓中基质细胞的相互作用来调节的。然而，调节 HSPC 与这些细胞相互作用的细胞机制及其对 HSPC 极性的潜在影响仍然知之甚少。在这里，我们评估了细胞与成骨细胞或内皮细胞接触对 HSPC 极性的影响。我们发现 HSPC 可以形成离散的接触位点，从而导致其细胞骨架结构的广泛极化。值得注意的是，中心体位于接触位点附近。HSPC 与骨髓基质细胞接触时的极化能力似乎是特异性的，因为在初级淋巴或骨髓细胞或与皮肤成纤维细胞接触的 HSPC 中未观察到这种能力。在极化接触中识别出受体 ICAM、VCAM 和 SDF1。只有 SDF1 能够独立诱导中心体-微管网络的极化。