lncRNA SOX2OT抑制海马神经发生促进脓毒症相关性脑病认知损伤的机制研究

It is of great needs to understand the mechanisms of non-reversible cognitive dysfunction in patients suffering from sepsis-associated encephalopathy (SAE) during surviving. The disorder of hippocampal neurogenesis is the critical reason of cognitive injury induced by SAE. LncRNA SOX2OT is a key factor in regulating neurogenesis, but its role in SAE remains unclear. Our previous work has found that the SOX2OT expression in hippocampus was involved in the development of hippocampal neurogenesis dysfunction and cognitive injury induced by SAE; furthermore, SOX2OT has been proven to combine with alternative splicing regulating factor PTBP1, and they were involved in regulating the balance of SOX2OT alternative splicing variants, respectively. We hypothesize that SOX2OT may recruit PTBP1, resulting in the change of its alternative splicing balance, and lead to the disorder of hippocampal neurogenesis and cognitive dysfunction induced by SAE. The present study intents to screen out alternative splicing variants of SOX2OT, and investigate the effects of SOX2OT on the balance of splicing variants and their associations with hippocampal neurogenesis and cognitive dysfunction induced by SAE; then demonstrate these effects in the vitro and in vivo experiments; finally clarify the mechanisms of SOX2OT recruiting PTBP1, regulating the balance of its alternative splicing, and subsequently regulating neurogenesis through a series of molecular biology experiments. Our study will provide new molecular target and theory evidences of protection against cognitive dysfunction induced by SAE clinically.

脓毒症相关性脑病（SAE）患者生存期不可逆的认知损伤是急需解决的问题。海马神经发生障碍是SAE认知损伤的主要原因。lncRNA SOX2OT是神经发生调节分子，但在SAE中的作用尚不清楚。我们前期研究发现，海马内SOX2OT表达与神经发生障碍和SAE认知损伤密切相关；SOX2OT可与选择性剪接调节因子PTBP1结合，两者均可影响SOX2OT剪接体的平衡。据此推测：SOX2OT通过招募PTBP1影响其剪接体平衡，调控神经发生，参与SAE认知损伤。本课题旨在：系统筛选SOX2OT剪接体，分析并获得SOX2OT影响剪接体及其与神经发生障碍、SAE认知损伤之间关系的证据；继而离体水平揭示SOX2OT影响剪接平衡对神经干细胞生物学功能的影响，并从整体水平加以验证；通过一系列分子生物学实验最终阐明SOX2OT通过招募PTBP1影响其剪接平衡调控神经发生的可能机制。为临床防治SAE提供新靶点和实验依据。

背景：脓毒症相关性脑病（SAE）患者生存期不可逆的认知损伤是急需解决的问题。长链非编码RNA SOX2OT是神经发生调节分子，C-X-C基序趋化因子受体5（CXCR5）可介导神经炎症，但在SAE中的作用尚不清楚。本研究拟探讨SOX2OT和CXCR5在SAE认知损伤中的作用和机制。.方法和结果：构建SOX2OT 和SOX2基因敲减的成年雄性小鼠，建立脓毒症模型。检测小鼠行为学，海马神经发生，SOX2OT、SOX2 mRNA、OCT4 mRNA水平。构建CXCR5敲除小鼠，建立脓毒症模型。检测小鼠行为学，海马小胶质细胞自噬、细胞极化和炎症反应， p38 MAPK磷酸化水平。原代培养的小胶质细胞经p38激动剂和抑制剂以及自噬抑制剂和激动剂预处理，转染CXCR5 siRNA，以LPS处理。检测细胞自噬、极化和炎症反应，以及p38、NF-κB和STAT3磷酸化水平。结果证实：脓毒症引起小鼠认知损伤，海马神经发生障碍，SOX2OT水平升高。SOX2OT siRNA通过SOX2 减轻脓毒症引起的海马神经发生障碍和认知损伤。脓毒症引起海马CXCR5表达增加，小胶质细胞自噬不完全活化，细胞向M1型转化，p38磷酸化水平增高。CXCR5基因敲除进一步激活海马小胶质细胞自噬，抑制细胞向M1转化，减轻炎症，改善脓毒症认知损伤。LPS引起小胶质细胞自噬不完全活化，细胞向M1转化，炎症因子释放，p38、NF-κB和STAT3磷酸化水平升高。CXCR5敲减抑制p38/NF-κB/STAT3信号的活化，进一步激活LPS处理的小胶质细胞自噬进而抑制炎症。自噬抑制剂逆转CXCR5 siRNA激活LPS处理细胞的自噬和抑制炎症的作用。.结论：SOX2OT 敲减下调SOX2表达改善脓毒症引起的海马神经发生障碍和认知损伤。CXCR5下调通过p38 MAPK/NF-κB/STAT3信号进一步激活海马小胶质细胞自噬改善脓毒症认知损伤。