miR‑29b affects neurocyte apoptosis by targeting MCL‑1 during cerebral ischemia/reperfusion injury

: The present study aimed to determine whether an miRNA (miR)-29b inhibitor protected against cerebral ischemia/reperfusion (I/R) injury in vitro and to investigate the underlying mechanisms. As a model for induced cerebral IR injury, N2a cells were exposed to an oxygen-glucose deprivation/reoxygenation (OGD/R) environment. Using this model, it was demonstrated that miR-29b was significantly upregulated compared with cells in a normal environment. The interactions between miR-29b and myeloid cell leukemia sequence (MCL)-1 were then investigated using dual-luciferase assays, revealing a strong regulation of MCL-1 through the 3'untranslated region. Using the OGD/R model, the present study additionally examined the effects of miR-29b and miR-29b inhibitor on cell viability and apoptosis using Cell Counting kit 8 and flow cytometry assays, respectively. miR-29b transfection led to increased N2a cell apoptosis and reduced cell viability under an OGD/R environment. However, this effect was reversed by the miR-29b inhibitor. Finally, the effects of miR-29b on the expression of several Wnt-associating proteins were examined. It was observed that B cell lymphoma-2 was inhibited by miR-29b, as was MCL-1, whereas caspase-3 expression was promoted. The miR-29b inhibitor demonstrated the opposite effect. Overall, miR-29b promoted neurocyte apoptosis by targeting MCL-1 during cerebral I/R injury. The results of the present study suggest a potential novel therapeutic target for the treatment of ischemic stroke.