Department of Medical Genetics, College of Basic Medical Science, Army Medical University (Third Military Medical University), Chongqing 400038, China.
Int J Mol Sci. 2023 Feb 3;24(3):3035. doi: 10.3390/ijms24033035.
The maintenance of neural stem cells (NSCs) plays a critical role in neurodevelopment and has been implicated in neurodevelopmental disorders (NDDs). However, the underlying mechanisms linking defective human neural stem cell self-renewal to NDDs remain undetermined. Our previous study found that haploinsufficiency causes cognitive and social behavior deficits by disrupting the stemness maintenance of NSCs in mice. However, its effects and underlying mechanisms have not been elucidated in human neural stem cells (hNSCs). Here, we generated induced pluripotent stem cells (iPSCs) and induced them into hNSCs. The results revealed that heterozygous hNSCs exhibit impaired proliferation, cell cycle arrest, and increased apoptosis. As the RNA-seq analysis showed, haploinsufficiency inhibited the PI3K/AKT/mTOR pathway, leading to rising autophagy, and further resulted in the dysregulated expression of multiple proteins related to cell proliferation and apoptotic process. Furthermore, the suppression of heterozygous hNSC self-renewal caused by autophagy activation could be rescued by MHY1485 treatment or reproduced in rapamycin-treated hNSCs. Thus, our results showed that was essential for hNSC self-renewal and its haploinsufficiency led to cell cycle arrest, impaired cell proliferation, and increased apoptosis of hNSCs by regulating the PI3K/AKT/mTOR/autophagy pathway. These provided a new insight to understand the causality between the heterozygous NSCs and NDDs in humans.
神经干细胞（NSCs）的维持在神经发育中起着关键作用，并与神经发育障碍（NDDs）有关。然而，将人类神经干细胞自我更新的缺陷与 NDDs 联系起来的潜在机制仍未确定。我们之前的研究发现，haploinsufficiency 通过破坏小鼠 NSCs 的干性维持，导致认知和社交行为缺陷。然而，其在人类神经干细胞（hNSCs）中的作用和潜在机制尚未阐明。在这里，我们生成了诱导多能干细胞（iPSCs），并将其诱导为 hNSCs。结果表明，杂合 hNSCs 表现出增殖受损、细胞周期停滞和凋亡增加。正如 RNA-seq 分析所示，haploinsufficiency 抑制了 PI3K/AKT/mTOR 通路，导致自噬增加，进而导致与细胞增殖和凋亡过程相关的多种蛋白质表达失调。此外，自噬激活引起的杂合 hNSC 自我更新抑制可以通过 MHY1485 处理或 rapamycin 处理的 hNSCs 来挽救。因此，我们的结果表明，在 hNSC 自我更新中，haploinsufficiency 通过调节 PI3K/AKT/mTOR/自噬通路，导致细胞周期停滞、增殖受损和凋亡增加。这些为理解人类杂合 NSCs 与 NDDs 之间的因果关系提供了新的见解。
