CD244 expression represents functional decline of murine hematopoietic stem cells after in vitro culture

Isolation of long-term hematopoietic stem cell (HSC) is possible by utilizing flow cytometry with multiple cell surface markers. However, those cell surface phenotypes do not represent functional HSCs after in vitro culture. Here we show that cultured HSCs express mast cell-related genes including Cd244. After in vitro culture, phenotypic HSCs were divided into CD244(-) and CD244(+) subpopulations, and only CD244: cells that have low mast cell gene expression and maintain HSC-related genes sustain reconstitution potential. The result was same when HSCs were cultured in an effluent expansion medium containing polyvinyl alcohol. Chemically induced enduplasmic reticulum (ER) stress signal increased the CD244(+) sul population, whereas ER stress suppression using a molecular chaperone, TUIX:A, decreased CD244(+) population, which was correlated to improved reconstitution output. These data sugest CD244 is a potent marker to exclude non-functional HSCs after in vitro culture thereby useful to elucidate mechanism of functional decline of HSCs during ex vivo treatment.

Automated summary

Isolation of long-term hematopoietic stem cell (HSC) is possible by utilizing flow cytometry with multiple cell surface markers. CD244 is identified as a potent marker to exclude non-functional HSCs and investigate the mechanism of HSC functional decline.