GSE171014
Competition between hematopoietic stem and progenitor cells controls the hematopoietic stem cell homeostasis [scRNA-seq]
Cellular competition for limiting hematopoietic factors is a physiologically regulated but poorly understood process. Here, we studied this phenomenon by hampering hematopoietic progenitor access to Leptin receptor+ mesenchymal stem/progenitor cells (MSPCs) and endothelial cells (ECs). We showed that HSC numbers increased by 2-fold when multipotent and lineage-restricted progenitors fail to respond to CXCL12 produced by MSPCs and ECs. HSCs were qualitatively normal, and HSC expansion only occurred when early hematopoietic progenitors but not differentiated hematopoietic cells lacked CXCR4. Furthermore, the MSPC and EC transcriptomic heterogeneity was remarkably stable, suggesting that it is impervious to dramatic changes in hematopoietic progenitor interactions. Instead, HSC expansion was caused by increased availability of membrane-bound stem cell factor (mSCF) on MSPCs and ECs due to reduced consumption by cKit-expressing hematopoietic progenitors. These studies revealed an intricate homeostatic balance between HSCs and proximal hematopoietic progenitors regulated by cell competition for limiting amounts of mSCF. Overall design: With bone marrow stromal cells of Cxcr4 conditional knockout (Flk2-cre+ Cxcr4fl/fl, cKO) mouse and littermate control (Flk2-cre+ Cxcr4fl/+, CTL), single cell RNA-sequencing analysis was performed.