MicroRNA-219 alleviates glutamate-induced neurotoxicity in cultured hippocampal neurons by targeting calmodulin-dependent protein kinase II gamma

Septic encephalopathy is a frequent complication of sepsis, but there are few studies examining the role of microRNAs (miRs) in its pathogenesis. In this study, a miR-219 mimic was transfected into rat hippocampal neurons to model miR-219 overexpression. A protective effect of miR-219 was observed for glutamate-induced neurotoxicity of rat hippocampal neurons, and an underlying mechanism involving calmodulin-dependent protein kinase II. (CaMKII gamma) was demonstrated. miR-219 and CaMKII gamma mRNA expression induced by glutamate in hippocampal neurons was determined by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). After neurons were transfected with miR-219 mimic, effects on cell viability and apoptosis were measured by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. In addition, a luciferase reporter gene system was used to confirm CaMKII. as a target gene of miR-219. Western blot assay and rescue experiments were also utilized to detect CaMKII gamma expression and further verify that miR-219 in hippocampal neurons exerted its effect through regulation of CaMKII gamma MTT assay and qRT-PCR results revealed obvious decreases in cell viability and miR-219 expression after glutamate stimulation, while CaMKII gamma mRNA expression was increased. MTT, flow cytometry, and caspase-3 activity assays showed that miR-219 overexpression could elevate glutamate-induced cell viability, and reduce cell apoptosis and caspase-3 activity. Moreover, luciferase CaMKII gamma-reporter activity was remarkably decreased by co-transfection with miR-219 mimic, and the results of a rescue experiment showed that CaMKII gamma overexpression could reverse the biological effects of miR-219. Collectively, these findings verify that miR-219 expression was decreased in glutamate-induced neurons, CaMKII gamma was a target gene of miR-219, and miR-219 alleviated glutamate-induced neuronal excitotoxicity by negatively controlling CaMKII gamma expression.