Novel differential calcium regulation of hematopoietic stem and progenitor cells under physiological low oxygen conditions.

Low oxygen bone marrow (BM) niches (~1%-4% low O ) provide critical signals for hematopoietic stem/progenitor cells (HSC/HSPCs). Our presented data are the first to investigate live, sorted HSC/HSPCs in their native low O conditions. Transcriptional and proteomic analysis uncovered differential Ca regulation that correlated with overlapping phenotypic populations consisting of robust increases of cytosolic and mitochondrial Ca , ABC transporter (ABCG2) expression and sodium/hydrogen exchanger (NHE1) expression in live, HSC/HSPCs remaining in constant low O We identified a novel Ca high population in HSPCs predominantly detected in low O that displayed enhanced frequency of phenotypic LSK/LSKCD150 in low O replating assays compared to Ca low populations.