Inhibition of inflammation and senescence with azole compound C7 enables expansion of hematopoietic stem and progenitor cells.

Human hematopoietic stem and progenitor cells (HSPCs) derived from umbilical cord blood (UCB) are often insufficient in quantity for transplantation, necessitating efforts for ex vivo expansion. We previously developed a novel azole-based small molecule, C7, as a structural analog of the p38 mitogen-activated protein kinase inhibitor SB203580. C7 mediated robust ex vivo expansion of UCB HSPCs from unselected mononuclear cells, compared to its structural analogs and other published compounds. However, the molecular underpinnings of C7's potency remained unclear. In this work, we demonstrate that C7 preferentially enhances the proliferation and viability of early HSPC subsets upon direct culture with pre-isolated HSPCs, while limiting mitochondrially-derived reactive oxygen species production linked to oxidative stress. C7 treatment enhances hematopoietic stem cell self-renewal and in vivo multilineage reconstitution without T- or myeloid lineage bias. Unlike existing p38 inhibitors, C7 targets multiple kinases and pathways to achieve superior HSPC expansion through suppression of NFκB and IL-10 inflammatory signaling and attenuation of stress/senescence‑associated markers (eg, SERPINB2 and CDKN1A/p21). This mechanism of action of C7 is distinct from those of other existing compounds used for ex vivo HSPC expansion and has implications for application in other ex vivo culture platforms and clinical settings.