Bcl11a maintains hematopoietic stem cell function but accelerates inflammation-driven exhaustion during aging

Preserving hematopoietic stem cell (HSC) functionality is essential for maintaining healthy blood and the immune system throughout life. HSC function declines with age; however, the underlying mechanisms are not fully understood. Using an inducible mosaic mouse model to overexpress the transcription factor Bcl11a in the hematopoietic compartment, we found that an aging-related increase in Bcl11a mitigated HSC functional decline, promoted IL-1β production in the bone marrow (BM), and accelerated HSC attrition in a non–cell-autonomous manner. Aging-related inflammation in the BM enhanced Bcl11a and Fc receptor (FcR) expression in HSCs, and FcR signaling induced HSC differentiation. This was counteracted by Bcl11a through repression of Fcer1g . Bcl11a up-regulation promoted IL-1β production in BM myeloid cells, driving inflammation and HSC deterioration. Deletion of Fcer1g , or blocking IL-1β signaling, eliminated this non–cell-autonomous effect on HSC decline. These findings demonstrate that Bcl11a plays a dual role in HSCs during aging not only by cell-intrinsically preserving HSC function but also by promoting BM inflammation and HSC dysfunction.