Wang Wenjia, Qiu Wenqiao, Chen Pengyu, Yang Zhijun, Zou Mingming, Zhou Yuhui, Guo Lili, Zou Dan, Xu Ruxiang, Gao Mou
Senior Department of Neurosurgery, The First Medical Center of PLA General Hospital, Beijing, 100853, China.
Department of ENT-HN, Hainan Hospital of PLA General Hospital, Sanya, 572013, China.
Stem Cell Res Ther. 2025 Jul 21;16(1):392. doi: 10.1186/s13287-025-04489-x.
Brain-derived neurotrophic factor (BDNF) has the capacity to promote neuronal survival that is crucial to neurological recovery after closed head injury (CHI). We previously reported that intracerebral-transplanted induced neural stem cells (iNSCs) can up-regulate BDNF levels to exert neurotrophic effects in CHI-damaged brains. Here we aim to elucidate the mechanism of BDNF up-regulation in iNSCs.
We performed iNSC and lipopolysaccharide (LPS)-activated microglia co-culture experiments, iNSC transplantation, loss-of-function study, morphological and molecular biological analyses to uncover the mechanism underlying the overexpression of BDNF in iNSCs.
Our results indicated that co-culture with LPS-activated microglia up-regulated the expression levels of BDNF, as well as Bdnf exons I and IV in iNSCs. Notably, AKT inhibition could counteract the effects of co-culture with LPS-activated microglia that decreased enhancer of zeste homolog 2 (EZH2) and H3K27 trimethylation (H3K27me3) levels at Bdnf promoter IV but increased EZH2 phosphorylation and BDNF expression in iNSCs. Additionally, blockage of AKT could counteract the effects of co-culture with LPS-activated microglia that increased cAMP response element binding protein (CREB) levels at Bdnf promoters I and IV, as well as CREB phosphorylation and BDNF expression in iNSCs. Furthermore, blocking AKT activity in grafted iNSCs could reduce BDNF expression in the injured cortices of CHI mice.
In short, our study shows that AKT signaling may regulate BDNF expression in iNSCs. Activation of AKT can up-regulate BDNF expression through inactivating EZH2 as well as reducing EZH2 and H3K27me3 levels at Bdnf promoter IV, meanwhile activating CREB as well as increasing CREB levels at Bdnf promoters I and IV.
脑源性神经营养因子（BDNF）具有促进神经元存活的能力，这对闭合性颅脑损伤（CHI）后的神经功能恢复至关重要。我们之前报道过，脑内移植诱导神经干细胞（iNSCs）可上调BDNF水平，从而在CHI损伤的大脑中发挥神经营养作用。在此，我们旨在阐明iNSCs中BDNF上调的机制。
我们进行了iNSC与脂多糖（LPS）激活的小胶质细胞共培养实验、iNSC移植、功能丧失研究、形态学和分子生物学分析，以揭示iNSCs中BDNF过表达的潜在机制。
我们的结果表明，与LPS激活的小胶质细胞共培养可上调iNSCs中BDNF以及Bdnf外显子I和IV的表达水平。值得注意的是，抑制AKT可抵消与LPS激活的小胶质细胞共培养的作用，该作用会降低Bdnf启动子IV处的zeste同源物2（EZH2）增强子和H3K27三甲基化（H3K27me3）水平，但会增加iNSCs中EZH2磷酸化和BDNF表达。此外，阻断AKT可抵消与LPS激活的小胶质细胞共培养的作用，该作用会增加Bdnf启动子I和IV处的cAMP反应元件结合蛋白（CREB）水平，以及iNSCs中CREB磷酸化和BDNF表达。此外，阻断移植的iNSCs中的AKT活性可降低CHI小鼠损伤皮质中的BDNF表达。
简而言之，我们的研究表明AKT信号通路可能调节iNSCs中的BDNF表达。激活AKT可通过使EZH2失活以及降低Bdnf启动子IV处的EZH2和H3K27me3水平来上调BDNF表达，同时激活CREB并增加Bdnf启动子I和IV处的CREB水平。
