Overexpressing Lnc240 Rescues Learning and Memory Dysfunction in Hepatic Encephalopathy Through Mir-1264-5p/mef2c Axis

Hepatic encephalopathy (HE) is a nervous system disease caused by severe liver diseases and different degrees of learning and memory dysfunction. Long non-coding RNA (lncRNA) is highly expressed in the brain and plays important roles in central nervous system diseases like Alzheimer's disease. In the present work, we found that the expression of lnc240 in the hippocampus of HE mice was significantly downregulated, but its pathogenesis in HE has not been clarified. This study aimed to explore the effects of lnc240 on the cognitive function of HE. The expression of lnc240, miR-1264-5p, and MEF2C was analyzed with RNA-seq and further determined by qRT-PCR in HE mouse. Double luciferase reporter gene testing confirmed the relationship between lnc240, MEF2C, and miR-1264-5p. The functional role of lnc240 and MEF2C in vitro and in vivo was evaluated by qRT-PCR, western blot analysis, immunofluorescence staining, Golgi staining, electrophysiology, and Morris water maze. The expression of lnc240 was decreased in HE mice. The overexpression of lnc240 could significantly downregulate miR-1264-5p and upregulate MEF2C, also increasing the amplitude and frequency of mEPSC in primary cultured hippocampal neurons. The overexpression of miR-1264-5p reversed the effect of lnc240 on MEF2C. Moreover, in vivo experiments have shown that the overexpression of lnc240 could improve HE mice's spatial learning and memory functions. Golgi staining suggested that overexpression of lnc240 could increase the density and maturity of dendritic spines in hippocampal neurons of HE mice. Lnc240 can regulate the expression of MEF2C through miR-1264-5p and regulate the synaptic plasticity of hippocampal neurons, thereby saving the learning and memory dysfunction in HE mice, suggesting that lnc240 might be a potential therapeutic target for the treatment of HE.