School of Biological Sciences, University of Adelaide, Adelaide, SA, AUS 5005, Australia.
Robinson Research Institute, University of Adelaide, Adelaide, SA, AUS 5005, Australia.
Sci Rep. 2017 Oct 3;7(1):12618. doi: 10.1038/s41598-017-12574-2.
DEPDC5 mutations have recently been shown to cause epilepsy in humans. Evidence from in vitro studies has implicated DEPDC5 as a negative regulator of mTORC1 during amino acid insufficiency as part of the GATOR1 complex. To investigate the role of DEPDC5 in vivo we generated a null mouse model using targeted CRISPR mutagenesis. Depdc5 homozygotes display severe phenotypic defects between 12.5-15.5 dpc, including hypotrophy, anaemia, oedema, and cranial dysmorphology as well as blood and lymphatic vascular defects. mTORC1 hyperactivity was observed in the brain of knockout embryos and in fibroblasts and neurospheres isolated from knockout embryos and cultured in nutrient deprived conditions. Heterozygous mice appeared to be normal and we found no evidence of increased susceptibility to seizures or tumorigenesis. Together, these data support mTORC1 hyperactivation as the likely pathogenic mechanism that underpins DEPDC5 loss of function in humans and highlights the potential utility of mTORC1 inhibitors in the treatment of DEPDC5-associated epilepsy.
DEPDC5 突变最近被证明会导致人类癫痫。体外研究的证据表明，DEPDC5 作为 GATOR1 复合物的一部分，在氨基酸不足时是 mTORC1 的负调节剂。为了研究 DEPDC5 在体内的作用，我们使用靶向 CRISPR 诱变生成了一个缺失小鼠模型。Depdc5 纯合子在 12.5-15.5 dpc 之间表现出严重的表型缺陷，包括萎缩、贫血、水肿和颅面畸形以及血液和淋巴管血管缺陷。在敲除胚胎的大脑以及从敲除胚胎分离并在营养剥夺条件下培养的成纤维细胞和神经球中观察到 mTORC1 过度活跃。杂合子小鼠似乎正常，我们没有发现癫痫发作或肿瘤形成易感性增加的证据。总之，这些数据支持 mTORC1 过度激活是 DEPDC5 功能丧失在人类中潜在的致病机制，并突出了 mTORC1 抑制剂在治疗 DEPDC5 相关癫痫中的潜在应用。
