CD61 enriches long-term repopulating hematopoietic stem cells

Among the subsets that define hematopoietic stem cells (HSCs), CD34− c-kit+ Sca-1+ lineage marker− (CD34−KSL) cells are regarded as one of the populations that have the highest enrichment of HSCs in adult mouse bone marrow. Here, we demonstrate that long-term repopulating hematopoietic stem cells (LTR-HSCs) have high expression of CD61 (integrin β3) within the CD34−KSL population. Approximately 60% of CD34−KSL cells showed high expression of CD61. CD61HighCD34−KSL populations also exhibited significantly greater properties of HSC, such as expression of HSC markers, the side population (SP) phenotype, and ability for long-term repopulation. In both SP cells and non-SP (NSP) cells, CD61HighCD34−KSL cells also contained significantly more LTR-HSCs than CD61Low/−CD34−KSL cells. Our results indicate that CD61 is exploitable for HSC enrichment as a supportive positive cell surface marker.