Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
Comprehensive Bone Marrow Failure Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
Sci Adv. 2024 Sep 20;10(38):eadq1476. doi: 10.1126/sciadv.adq1476. Epub 2024 Sep 18.
Cross-talk between hematopoietic stem and progenitor cells (HSPCs) and bone marrow (BM) cells is critical for homing and sustained engraftment after transplantation. In particular, molecular and physical adaptation of sinusoidal endothelial cells (ECs) promote HSPC BM occupancy; however, signals that govern these events are not well understood. Extracellular vesicles (EVs) are mediators of cell-cell communication crucial in shaping tissue microenvironments. Here, we demonstrate that integrin α4β7 on murine HSPC EVs targets uptake into ECs. In BM ECs, HSPC EVs induce up-regulation of C-C motif chemokine receptor 2 (CCR2) ligands that synergize with CXCL12-CXCR4 signaling to promote BM homing. In nonirradiated murine models, marrow preconditioning with HSPC EVs or recombinant CCR2 ligands improves homing and early graft occupancy after transplantation. These findings identify a role for HSPC EVs in remodeling ECs, newly define CCR2-dependent graft homing, and inform novel translational conditioning strategies to improve HSPC transplantation.
造血干细胞和祖细胞 (HSPCs) 与骨髓 (BM) 细胞之间的串扰对于移植后的归巢和持续植入至关重要。特别是,窦状内皮细胞 (ECs) 的分子和物理适应促进了 HSPCs 在 BM 中的占据;然而,调控这些事件的信号尚未得到很好的理解。细胞外囊泡 (EVs) 是细胞间通讯的介质,对于塑造组织微环境至关重要。在这里,我们证明了小鼠 HSPC EVs 上的整合素 α4β7 靶向进入 ECs 的摄取。在 BM ECs 中,HSPC EVs 诱导 C-C 基序趋化因子受体 2 (CCR2) 配体的上调,这些配体与 CXCL12-CXCR4 信号协同作用,促进 BM 归巢。在未辐照的小鼠模型中,用 HSPC EVs 或重组 CCR2 配体预处理骨髓可改善移植后的归巢和早期移植物占据。这些发现确定了 HSPC EVs 在重塑 ECs 中的作用,新定义了 CCR2 依赖性移植物归巢,并为改善 HSPC 移植提供了新的转化条件策略。
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