Comprehensive transcriptome analysis of the neural stem cell and brain in control and NSC-specific (P)RR deficienct mice.

(Pro)renin receptor [(P)RR] is a single-pass transmembrane protein and is widely expressed in mammalian tissues. (P)RR acts as a component of the vacuolar ATPase in lysosomes, contributing to the degradation function and autophagy. Mutations in the (P)RR-coding ATP6AP2 have been reported to cause clinical conditions such as X-linked parkinsonism with spasticity. However, our understanding of the role of (P)RR in the whole brain development remains incomplete. We generated mice with neural stem cell (NSC)-specific (P)RR deficiency (CKO). CKO mice exhibited significant brain atrophy during mid-gestation, leading to perinatal lethality. Fetal CKO brains showed lateral ventricular enlargement with malformation of neocortex and ganglionic eminence (GE) from mid-gestation. CKO brains showed massive apoptosis of neuroblasts and other cell types along with microglial activation at E15. We found that CKO NSCs showed reduced proliferation in the primary neurosphere state, while it was recovered after passage, suggesting that (P)RR is not essential for NSCs self-renewal. We also show that cells in the CKO neocortex showed normal proliferation at E15. In this study, to understand the molecular basis of ATP6AP2-mediated neural stem cell development, we performed a comprehensive analysis of gene expression changes in neural stem cells and whole brain of (P)RR CKO micec using the next-generation RNA sequencing (RNA-seq). mRNA profiles of whole brain and neural stem cell were generated by RNA sequencing using the Illumina NexSeq 500 (Illumina).

(前)肾素受体(Pro)renin receptor, (P)RR是一类单次跨膜蛋白，广泛表达于哺乳动物各类组织中。(P)RR可作为溶酶体中液泡型ATP酶(vacuolar ATPase)的组成组分，参与溶酶体的降解功能与自噬过程。编码(P)RR的ATP6AP2基因发生突变，可引发X连锁痉挛性帕金森症等临床病症。然而，目前学界对(P)RR在全脑发育中的调控作用仍未完全阐明。本研究构建了神经干细胞(NSC)特异性(P)RR条件性敲除(CKO)小鼠模型。CKO小鼠在妊娠中期即出现显著脑萎缩，最终导致围产期致死。妊娠中期的CKO胎鼠脑组织可见侧脑室扩张，同时伴随新皮层与神经节隆起(GE, ganglionic eminence)发育畸形。在胚胎第15天（E15），CKO小鼠脑组织可见成神经细胞及其他细胞类型发生大量凋亡，同时伴随小胶质细胞激活。研究发现，原代培养状态下的CKO神经干细胞增殖能力下降，但该缺陷可在传代后得到恢复，提示(P)RR并非神经干细胞自我更新所必需。此外，本研究还观察到，E15天CKO小鼠新皮层内的细胞增殖水平未出现异常。为阐明ATP6AP2介导的神经干细胞发育的分子机制，本研究通过下一代RNA测序(RNA-seq, next-generation RNA sequencing)，对(P)RR CKO小鼠的神经干细胞与全脑组织的基因表达变化进行了全面分析。本研究采用Illumina NexSeq 500（Illumina）测序平台，完成了全脑组织与神经干细胞的mRNA转录组测序，获取其表达谱数据。