Abstract: Objective To explore the clinical significance of miR-423-5p in ischemic stroke and its effects on SH-SY5Y cell apoptosis along with the underlying mechanisms. Methods Plasma samples were collected from three stroke-prone patients who subsequently developed acute ischemic stroke (AIS) within 24 hours. High-throughput sequencing was used to identify miR-423-5p as a key target. Venous blood samples were collected from 46 AIS patients within 24 hours of onset and from 46 matched control cases. RT-qPCR was performed to measure the plasma expression of miR-423-5p in both groups. The diagnostic value of miR-423-5p for AIS was evaluated using receiver operating characteristic (ROC) curve. After overexpression and knockdown of miR-423-5p in SH-SY5Y cells, flow cytometry was performed to detect apoptosis in each group to analyze the potential relationship between miR-423-5p and SH-SY5Y cell apoptosis. Western blot was used to measure changes in the expression level of the apoptotic protein cleaved caspase-3 and the anti-apoptotic proteins Bcl-2 and Bcl-xL. Results The expression of miR-423-5p in 3 AIS patients showed significant difference before and after onset. Plasma miR-423-5p expression was significantly elevated in AIS patients versus controls (P＜0.001). ROC analysis indicated its strong diagnostic potential for AIS. Overexpression of miR-423-5p increased the apoptosis rate and cleaved caspase-3 expression of SH-SY5Y cells after OGD/R, and decreased the expression of Bcl-2 and Bcl-xL, while knocking down miR-423-5p had the opposite effect. Conclusions The expression of miR-423-5p is upregulated in the plasma of patients with ischemic stroke compared to healthy controls. Furthermore, miR-423-5p promotes OGD/R-induced apoptosis in SH-SY5Y cells by increasing the level of cleaved caspase-3 and suppressing the expression of Bcl-2 and Bcl-xL.

Key words: miR-423-5p, ischemic stroke, biomarker, apoptosis