Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China.
Int J Mol Sci. 2023 Jun 19;24(12):10324. doi: 10.3390/ijms241210324.
Neural stem cells (NSCs) persist in the subgranular zone (SGZ) throughout the lifespan and hold immense potential for the repair and regeneration of the central nervous system, including hippocampal-related diseases. Several studies have demonstrated that cellular communication network protein 3 (CCN3) regulates multiple types of stem cells. However, the role of CCN3 in NSCs remains unknown. In this study, we identified CCN3 expression in mouse hippocampal NSCs and observed that supplementing CCN3 improved cell viability in a concentration-dependent manner. Additionally, in vivo results showed that the injection of CCN3 in the dentate gyrus (DG) increased Ki-67- and SOX2-positive cells while decreasing neuron-specific class III beta-tubulin (Tuj1) and doublecortin (DCX)-positive cells. Consistently with the in vivo results, supplementing CCN3 in the medium increased the number of BrdU and Ki-67 cells and the proliferation index but decreased the number of Tuj1 and DCX cells. Conversely, both the in vivo and in vitro knockdown of the gene in NSCs had opposite effects. Further investigations revealed that CCN3 promoted cleaved Notch1 (NICD) expression, leading to the suppression of PTEN expression and eventual promotion of AKT activation. In contrast, knockdown inhibited the activation of the Notch/PTEN/AKT pathway. Finally, the effects of changes in CCN3 protein expression on NSC proliferation and differentiation were eliminated by FLI-06 (a Notch inhibitor) and VO-OH (a PTEN inhibitor). Our findings imply that while promoting proliferation, CCN3 inhibits the neuronal differentiation of mouse hippocampal NSCs and that the Notch/PTEN/AKT pathway may be a potential intracellular target of CCN3. Our findings may help develop strategies to enhance the intrinsic potential for brain regeneration after injuries, particularly stem cell treatment for hippocampal-related diseases.
神经干细胞 (NSCs) 在整个生命过程中存在于颗粒下区 (SGZ)，对中枢神经系统的修复和再生具有巨大的潜力，包括与海马相关的疾病。几项研究表明，细胞通讯网络蛋白 3 (CCN3) 调节多种类型的干细胞。然而，CCN3 在 NSCs 中的作用尚不清楚。在这项研究中，我们鉴定了小鼠海马 NSCs 中的 CCN3 表达，并观察到 CCN3 的补充以浓度依赖的方式提高了细胞活力。此外，体内结果表明，在齿状回 (DG) 中注射 CCN3 增加了 Ki-67 和 SOX2 阳性细胞，同时减少了神经元特异性 III 类β-微管蛋白 (Tuj1) 和双皮质素 (DCX) 阳性细胞。与体内结果一致，在培养基中补充 CCN3 增加了 BrdU 和 Ki-67 细胞的数量和增殖指数，但减少了 Tuj1 和 DCX 细胞的数量。相反，在 NSCs 中体内和体外敲低 基因均产生相反的效果。进一步的研究表明，CCN3 促进了裂解的 Notch1 (NICD) 的表达，导致 PTEN 表达的抑制和 AKT 的最终激活。相反， 敲低抑制了 Notch/PTEN/AKT 通路的激活。最后，通过 FLI-06（一种 Notch 抑制剂）和 VO-OH（一种 PTEN 抑制剂）消除了 CCN3 蛋白表达变化对 NSC 增殖和分化的影响。我们的研究结果表明，CCN3 在促进增殖的同时抑制了小鼠海马 NSCs 的神经元分化，而 Notch/PTEN/AKT 通路可能是 CCN3 的潜在细胞内靶点。我们的研究结果可能有助于制定策略来增强受伤后大脑再生的内在潜力，特别是用于与海马相关的疾病的干细胞治疗。
