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.