MAS1L and Stroke: We have evidence that administration of PMSCs, or exosomes derived from PMSCs, to a stroke model enhances the ACE2-Ang 1–7/1–9-MasR/AT2R pathway, while circumventing issues of injecting immunogenic stem cells, inadvertent blockade of the ACE2 cascade, and failure of treatments that target pathways leading to stroke injury because CBF has not been adequately restored.