LncRNA MEG3 inhibits the proliferation of neural stem cells after ischemic stroke via the miR-493–5P/MIF axis

Abstract

ObjectiveThe proliferation of neural stem cells (NSCs11NSCs: neural stem cells.), or lack thereof, can have profound effects on brain tissue remodeling for ischemic stroke (IS22IS: ischemic stroke.). In this study, we aimed to reveal the influence of the lncRNA MEG3/miR-493–5p/MIF axis on NSC proliferation after IS. MethodsWe established an oxygen glucose-deprivation/reoxygenation (OGD/R33OGD/R: oxygen and glucose confinement/reoxygenation.) in vitro model of IS in NSCs. We evaluated NSC isolation efficiency and proliferation by NESTIN, SOX2, and PCNA immunofluorescence staining. MEG3 and miR-493–5P levels were assessed by quantitative real-time polymerase chain reaction (qRT-PCR44qRT-PCR: quantitative real-time polymerase chain reaction.). Changes in MIF protein expression levels were analyzed using Western blotting. We then evaluated the role of MEG3 and miR-493–5p by transfection of si-MEG3, a miR-493–5p mimic, or miR-493–5p inhibitor. NSC proliferation was quantified using Cell Counting Kit-8 analysis. ResultsNESTIN and SOX2 were co-expressed in endogenous NSCs. Following OGD/R, MEG3 and miR-493–5P were significantly upregulated in NSCs, while MIF levels decreased and proliferation was inhibited. Knockdown of MEG3 inhibited miR-493–5p and rescued expression of MIF and PCNA, restoring cellular proliferation levels. In NSCs transfected with a miR-493–5p mimic or inhibitor, MIF levels were down- or upregulated, respectively. Consistently, transfection of a miR-493–5p mimic reduced NSC proliferation, while transfection with a miR-493–5p inhibitor or si-MEG3 rescued the inhibitory effect of OGD/R on NSC proliferation. After co-transfection of si-MEG3 and a miR-493–5p mimic of OGD/R-induced NSCs, levels of PCNA, an indicator of cellular proliferation, were significantly reduced. Conclusion MEG3 inhibits NSC proliferation of after IS via positive regulation of miR-493–5p and potential subsequent downregulation of MIF.