Abstract: BACKGROUND: Long non-coding RNA (LncRNA) plays an important role in nervous system development and neurological diseases. Previous studies by the research team have demonstrated that human umbilical cord mesenchymal stem cells overexpressing erythropoietin (EPO-MSCs) under ischemic and hypoxic conditions have better neuroprotective functions and significantly activate the expression of LncRNA XIST. Research suggests that XIST is related to the pathogenesis of hypoxic-ischemic encephalopathy, but the role and mechanism of its regulation by EPO-MSCs in protecting ischemic-hypoxic neurons remain unclear.
OBJECTIVE: To explore the new mechanism by which LncRNA XIST, in response to EPO-MSC signaling, affects the apoptosis of ischemic-hypoxic SH-SY5Y cells.
METHODS: (1) SH-SY5Y cell lines with knockdown of LncRNA XIST (sh-XIST) and negative control (NC-XIST) were constructed through lentiviral transfection. Oxygen-glucose deprivation was used to induce ischemic-hypoxic injury in the cells. Transwell chambers were used to create a non-contact co-culture system with EPO-MSCs, sh-XIST, and NC-XIST ischemic-hypoxic SH-SY5Y cells. Cell proliferation ability was detected using the CCK-8 assay. Cell migration ability was assessed using the scratch assay, and cell apoptosis was measured by flow cytometry. (2) RNA-seq bioinformatics analysis was performed to screen for differentially expressed genes and pathways between sh-XIST and NC-XIST cell lines. Dual-luciferase experiments were used to verify the relationship between miR-124-3p and the target genes XIST and GRIN1. qRT-PCR was conducted to validate the expression levels of downstream miR-124-3p and GRIN1 genes. (3) miR-124-3p inhibitors and mimics were added to verify phenotypic changes in SH-SY5Y cells after ischemic-hypoxic injury and co-culture with EPO-MSCs.
RESULTS AND CONCLUSION: (1) Compared with the NC-XIST group, SH-SY5Y cells in the sh-XIST group showed reduced proliferation and migration abilities and increased apoptosis after ischemic-hypoxic injury and co-culture with EPO-MSCs. (2) Dual-luciferase experiments showed that miR-124-3p interacted with the target gene XIST. SH-SY5Y cells transfected with miR-124-3p mimics and co-cultured with EPO-MSCs showed decreased apoptosis after ischemic-hypoxic injury, while SH-SY5Y cells transfected with miR-124-3p inhibitors showed increased apoptosis after co-culture with EPO-MSCs. (3) Transcriptomic sequencing and bioinformatics analysis of sh-XIST revealed significant downregulation of the neuroactive ligand-receptor pathway and the key receptor gene GRIN1 for central nervous system development. (4) Dual-luciferase experiments showed that miR-124-3p interacted with GRIN1. GRIN1 expression was significantly downregulated in the sh-XIST group after ischemic-hypoxic injury compared with the NC-XIST group. These findings indicate that LncRNA XIST promotes GRIN1 expression by upregulating miR-124-3p, thereby reducing cell apoptosis after ischemic-hypoxic injury and co-culture with EPO-MSCs and enhancing proliferation and migration. sh-XIST can block this protective function.

Key words: 缺血缺氧脑病, 促红细胞生成素, 脐带间充质干细胞, 长链非编码RNA, 基因修饰, XIST, miR-124-3p, GRIN1, 工程化干细胞