PIEZO1 Activation‐Mediated Generation of Transgene‐Free Long‐Term Hematopoietic Stem Cells

ABSTRACT The development of engraftable, long‐term reconstituting hematopoietic stem cells (LT‐HSC) from human pluripotent stem cells (hPSC) has been a long‐sought goal. Since HSCs are formed by a subset of endothelial cells in the ventral part of the dorsal aorta, we analyzed heartbeat‐mediated pulsatile displacement experienced by the walls of the dorsal aorta in zebrafish embryos. We found that pulsation‐mediated circumferential stretch was restricted to the ventral part of the dorsal aorta and activated Piezo1 to stimulate LT‐HSC formation. Stimulation of pulsation or Yoda1‐mediated Piezo1 activation promoted the formation of de novo LT‐HSCs from hemogenic endothelial cells derived from murine embryos or human pluripotent stem cells. These HSCs gave long‐term multilineage reconstitution of hematopoietic cells upon transplantation into immunocompromised mice. The formation of transgene‐free human LT‐HSCs that can engraft and reconstitute the hematopoietic system will facilitate the generation of off‐the‐shelf HSCs from hPSCs for use in cellular therapies.