Transplanting rejuvenated blood stem cells extends lifespan of aged immunocompromised mice.

One goal of regenerative medicine is to rejuvenate tissues and extend lifespan by restoring the function of endogenous aged stem cells. However, evidence that somatic stem cells can be targeted in vivo to extend lifespan is still lacking. Here, we demonstrate that after a short systemic treatment with a specific inhibitor of the small RhoGTPase Cdc42 (CASIN), transplanting aged hematopoietic stem cells (HSCs) from treated mice is sufficient to extend the healthspan and lifespan of aged immunocompromised mice without additional treatment. In detail, we show that systemic CASIN treatment improves strength and endurance of aged mice by increasing the myogenic regenerative potential of aged skeletal muscle stem cells. Further, we show that CASIN modifies niche localization and H4K16ac polarity of HSCs in vivo. Single-cell profiling reveals changes in HSC transcriptome, which underlie enhanced lymphoid and regenerative capacity in serial transplantation assays. Overall, we provide proof-of-concept evidence that a short systemic treatment to decrease Cdc42 activity improves the regenerative capacity of different endogenous aged stem cells in vivo, and that rejuvenated HSCs exert a broad systemic effect sufficient to extend murine health- and lifespan.

Downregulation of CDC42 inhibits the proliferation and stemness of human trophoblast stem cell via EZRIN/YAP inactivation.

Placental dysplasia increases the risk of recurrent spontaneous abortion (RSA). However, the underlying mechanism regulating placental development remains unclear. In this study, we showed that the expression of CDC42 was decreased in the villous tissue of RSA samples compared to healthy controls. Further examination demonstrated that CDC42 deficiency led to the differentiation of human trophoblast stem cells (hTSCs) and inhibited their proliferation. Genetic manipulation of YAP and EZRIN in hTSCs revealed that CDC42 regulates the stemness and proliferation of hTSCs; this is dependent on EZRIN, which translocates YAP into the nucleus. Moreover, the expression pattern of EZRIN, YAP, and Ki67 was also abnormal in the villous tissue of RSA samples, consistent with in vitro experiments. In summary, these findings suggest that the CDC42/EZRIN/YAP pathway plays an important role in placental development.