陆军军医大学学报 (Jul 2022)
MicroRNA-124 promotes neurite elongation and motor function recovery in mice with cerebral ischemia injury by targeting PTEN
Abstract
Objective To explore the effect of microRNA-124 (miR-124) on the improvement of neurological function in mice with cerebral ischemia injury and its underlying mechanism. Methods ① A total of 32 C57 mice were randomly divided into sham group and cerebral ischemia group (n=16). The cerebral infarction area was detected by TTC staining and motor status of the mice was evaluated with neurobehavioral scoring in 3 d after brain injury. The expression change of miR-124 was detected by RT-qPCR and compared between the 2 groups. ② Primary neurons were isolated from fetal mice and cultured, and ischemia-reperfusion injury was simulated by oxygen glucose deprivation. The changes of miR-124 at 0 and 72 h after oxygen glucose deprivation were observed. ③ Another 32 C57 mice were randomly divided into cerebral ischemia group and cerebral ischemia+miR-124 group (n=16). TTC staining, rotating rod test and limb placement test were performed respectively to detect whether the motor function of the mice was improved. ④ The primary neurons were divided into oxygen-glucose deprivation group and oxygen-glucose deprivation+miR-124 group. The neurite elongation in the 2 groups was detected by immunofluorescence assay. The downstream target gene of miR-124 was predicted with Targetscan database. Double luciferase gene reporter assay and Western blotting were used to verify the effectiveness of miR-124 regulation on phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in the control and miR-124 groups. Then, the effect of PTEN up-regulation on neurite elongation was observed in the oxygen glucose deprivation+miR-124 cells and oxygen glucose deprivation+miR-124+PTEN groups. ⑤ Rotating rod test and limb placement test were performed again for motor functions in the mice of cerebral ischemia+miR-124 group and cerebral ischemia+miR-124+PTEN group (n=8). Results Cerebral ischemia-reperfusion resulted in the area of cerebral infarction about 40% (P < 0.001) and significantly reduced neurocognitive function in mice (P < 0.001), reaching the condition of severe cognitive impairment. The expression of miR-124 was significantly higher in the cerebral ischemia group than the control group (P < 0.05). Overexpression of miR-124 could promote the growth of neuronal axons after oxygen glucose deprivation (P < 0.05), reduce the area of cerebral infarction (P < 0.05), and thus promote the recovery and improvement of animal motor ability (P < 0.05). With the aid of Targetscan database, PTEN was predicted as the downstream target of miR-124, and double luciferase gene reporter assay and Western blotting confirmed that miR-124 could effectively down-regulate the expression of PTEN (P < 0.05); Finally, up-regulation of PTEN reversed the effect of miR-124 on promoting the growth of neuronal axons and improving the motor ability of mice (P < 0.05). Conclusion MiR-124 promotes neuronal axonal growth and contributes to the recovery of motor function in mice with cerebral ischemia by down-regulating PTEN.
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