Stroma-Derived Connective Tissue Growth Factor Maintains Cell Cycle Progression and Repopulation Activity of Hematopoietic Stem Cells In?Vitro

摘要

Summary Hematopoietic stem cells (HSCs) are preserved in co-cultures with UG26-1B6 stromal cells or their conditioned medium. We performed a genome-wide study of gene expression changes of UG26-1B6 stromal cells in contact with Lineage? SCA-1+ KIT+ (LSK) cells. This analysis identified connective tissue growth factor (CTGF) to be upregulated in response to {LSK} cells. We found that co-culture of {HSCs} on {CTGF} knockdown stroma (shCtgf) shows impaired engraftment and long-term quality. Further experiments demonstrated that CD34? CD48? CD150+ {LSK} (CD34? SLAM) cell numbers from shCtgf co-cultures increase in {G0} and senescence and show delayed time to first cell division. To understand this observation, a {CTGF} signaling network model was assembled, which was experimentally validated. In co-culture experiments of CD34? {SLAM} cells with shCtgf stromal cells, we found that SMAD2/3-dependent signaling was activated, with increasing p27Kip1 expression and downregulating cyclin D1. Our data support the view that {LSK} cells modulate gene expression in the niche to maintain repopulating {HSC} activity.