Discrimination of dormant and active hematopoietic stem cells by G0 markers reveals dormancy regulation by cytoplasmic calcium. Discrimination of dormant and active hematopoietic stem cells by G0 markers reveals dormancy regulation by cytoplasmic calcium

Quiescent hematopoietic stem cells (HSCs) are typically dormant, and only a few quiescent HSCs are active. The relationship between “dormant” and “active” HSCs remains unresolved. Here we generated a G0 marker (G0M) mouse line that visualizes quiescent cells. G0M identifies a small population of active HSCs (G0Mlow), which are distinct from dormant HSCs (G0Mhigh), within the conventional quiescent HSC fraction. Single-cell RNA-Seq analyses showed that the gene expression profiles of these populations were nearly identical, yet differed in their Cdk4/6 activity. Furthermore high-throughput small molecule screening revealed that high concentrations of cytoplasmic calcium ([Ca2+]c) were linked to dormancy of HSCs. These findings indicate that G0M separates dormant and active adult HSCs, which are regulated by Cdk4/6 and [Ca2+]c. This G0M mouse line represents a useful resource for investigating physiologically important stem cell subpopulations. Overall design: RNA sequencing of mouse bone marrow HSCs treated with or without LPS