RESUMO
OBJECTIVE: To investigate the clinical significance of miR-499a expression in the serum of ischemic stroke patients and its potential mechanism in regulating astrocytes to promote ischemic stroke. METHODS: Serum samples from 99 ischemic stroke patients and 99 healthy individuals were collected and analyzed for miR-499a expression through RT-PCR. Statistical analysis was performed to compare the expression differences between the two groups, and correlation between miR-499a expression and clinical pathological indices in stroke patients was analyzed. MiR-499a mimic, inhibitor, and negative control vectors were constructed and transfected into astrocyte SVGp12 cells. Afterward, miR-499a expression was validated by RT-PCR, cell viability was assessed by CCK8 assay, and apoptosis was detected using flow cytometry. The binding sites of miR-499a and Beclin1 were predicted by the Target-scan database and confirmed by dual luciferase assay. After overexpressing Beclin1, co-transfection with miR-499a mimic or negative control was conducted to observe the reverse effect of miR-499a mimic on Beclin1 overexpression. RESULTS: MiR-499a was significantly upregulated in the stroke group (p<0.001), it was positively correlated with TC (Total Cholesterol), LDL-C (Low-density lipoprotein cholesterol), and APO-A1 (Apolipoprotein A1) (R2>0.3, p<0.001). MiR-499a mimics promoted cell viability while inhibiting apoptosis of astrocytes. MiR-499a targeted Beclin 1 and inhibited its mRNA and protein expression, as well as the expression of autophagy-related proteins LC-3 and p62. MiR-499a could reverse the impact of Beclin1 overexpression on SVGp12 astrocyte proliferation and apoptosis. CONCLUSION: Serum miR-499a in stroke patients may serve as a potential diagnostic indicator. MiR-499a-mediated inhibition of Beclin 1, subsequently leading to suppression of astrocytic autophagy and viability, may represent a pivotal mechanism underlying its promotion of IS.
