运用单细胞测序技术研究SHH信号通路介导的小脑发育和肿瘤病变中的神经干细胞和肿瘤干细胞的细胞亚群和谱系发生

小脑发育和小脑髓母细胞瘤发生的调控机制尚不清楚。我们前期利用4种转基因动物（Math1-GFP、Dcx-DsRed、Patched+/-、Trim32KT）及其杂交后代，研究发现①小脑发育中SHH信号通路的激活改变细胞分裂轴进而调控神经干细胞的对称不对称分裂模式。②对称不对称分裂关键调控因子和抑癌基因Trim32通过结合并降解SHH信号通路中的关键因子Gli1从而影响发育和抑制肿瘤。③对神经干细胞进行单细胞测序，通过聚类分析显示：神经干细胞中存在一群Pax2阳性的中间神经元细胞群；细胞分泌蛋白C1ql1可能调控信息传递；颗粒神经元的细胞周期各期比例在发育中的变化；细胞命运分子在G2/M期颗粒神经元前体细胞中表达水平等等。以此，我们提出：能否利用单细胞测序技术和这些转基因小鼠找到调控小脑发育与肿瘤发生的神经干细胞和肿瘤干细胞的细胞亚群，从而找到调控小脑发育和肿瘤的新的方法？

The regulatory mechanisms of cerebellar development and medulloblastoma are still unclear. In our previous studies, using four transgenic animals (Math1-GFP, Dcx-DsRed, Patched+/-, Trim32KT) and their hybrid progenies, we found that: (1) activation of Sonic Hedgehog signaling pathway during cerebellar development alters the cell division axis and regulates the asymmetric division pattern of neural stem cells. (2) Trim32, a key regulator of cell division modes and a tumor suppressor, suppresses cerebellar development and tumorigenesis by degrading Gli1/Sonic Hedgehog Signaling. (3) Single-cell profiling of neural stem cells showed that there was a group of Pax2-positive intermediate neurons in NSCs; secretory protein C1ql1 might regulate cellular interaction between cell subsets; the proportion of different phases of cell cycle of granular neurons in cerebellar development; and the expression level of cell fate determinants in G2/M phase of granule neuronal progenitors. Based on these findings, we propose here whether we can identify subpopulations of neural stem cells and cancer stem cells that regulate cerebellar development and tumorigenesis using single-cell profiling technology and these transgenic mice and whether we can find new targets of SHH signaling which will provide new ways to regulate cerebellar development and tumors.