Laboratorios de Investigación Aplicada en Neurociencias (LIAN-CONICET), Fundación Para La Lucha Contra Las Enfermedades Neurológicas de La Infancia (Fleni), Ruta 9, Km 52.5, B1625XAF, Belén de Escobar, Provincia de Buenos Aires, Argentina.
Sci Rep. 2022 Nov 5;12(1):18803. doi: 10.1038/s41598-022-23650-7.
Human embryonic and induced pluripotent stem cells are self-renewing pluripotent stem cells (hPSCs) that can differentiate into a wide range of specialized cells. Although moderate hypoxia (5% O) improves hPSC self-renewal, pluripotency, and cell survival, the effect of acute severe hypoxia (1% O) on hPSC viability is still not fully elucidated. In this sense, we explore the consequences of acute hypoxia on hPSC survival by culturing them under acute (maximum of 24 h) physical severe hypoxia (1% O). After 24 h of hypoxia, we observed HIF-1α stabilization concomitant with a decrease in cell viability. We also observed an increase in the apoptotic rate (western blot analysis revealed activation of CASPASE-9, CASPASE-3, and PARP cleavage after hypoxia induction). Besides, siRNA-mediated downregulation of HIF-1α and P53 did not significantly alter hPSC apoptosis induced by hypoxia. Finally, the analysis of BCL-2 family protein expression levels disclosed a shift in the balance between pro- and anti-apoptotic proteins (evidenced by an increase in BAX/MCL-1 ratio) caused by hypoxia. We demonstrated that acute physical hypoxia reduced hPSC survival and triggered apoptosis by a HIF-1α and P53 independent mechanism.
人类胚胎干细胞和诱导多能干细胞是自我更新的多能干细胞（hPSCs），可以分化为广泛的特化细胞。尽管适度的低氧（5% O）可以提高 hPSC 的自我更新、多能性和细胞存活，但急性严重低氧（1% O）对 hPSC 活力的影响仍不完全清楚。在这种情况下，我们通过在急性（最长 24 小时）物理严重低氧（1% O）下培养 hPSC 来探索急性低氧对 hPSC 存活的影响。在低氧 24 小时后，我们观察到 HIF-1α 的稳定，同时伴随着细胞活力的下降。我们还观察到凋亡率的增加（Western blot 分析显示，在低氧诱导后，CASPASE-9、CASPASE-3 和 PARP 切割被激活）。此外，HIF-1α 和 P53 的 siRNA 介导下调并没有显著改变低氧诱导的 hPSC 凋亡。最后，BCL-2 家族蛋白表达水平的分析揭示了低氧引起的促凋亡和抗凋亡蛋白之间平衡的改变（通过 BAX/MCL-1 比值的增加来证明）。我们证明了急性物理低氧通过 HIF-1α 和 P53 非依赖性机制降低 hPSC 的存活并触发凋亡。
