Up-regulation of serum- and glucocorticoid-induced protein kinase 1 in the brain tissue of human and experimental epilepsy

Several studies have shown that serum- and glucocorticoid-induced protein kinase 1(SGK1) can regulate both glutamate receptors and glutamate transporters and may participate in the regulation of neuroexcitability in neuronal diseases. In our previous study, we analyzed differential gene expression in the anterior temporal neocortex of drug-refractory epilepsy patients relative to control patients using a complementary DNA microarray and found that the SGK1 gene was up-regulated more than twofold in the brain tissues of epileptic patients. In the current study, we measured SGK1 expression in the brain tissues of humans and in an experimental model of rat epilepsy in order to explore the relationship between SGK1 expression and epilepsy. The SGK1 expression was detected in thirty human brain tissues derived from patients undergoing operation for drug-refractory epilepsy and was also detected in eight samples from autopsies. Meanwhile, we investigated SGK1 expression during the epileptic process in rats using immunofluorescence, RT-PCR and western blot analysis. SGK1 expression was enhanced in the temporal neocortex of patients with drug-refractory epilepsy and was also highly expressed in the rat brain during different phases of the epileptic process. SGK1 expression was also related with the elevation of EAAT3, which expression reduced after knockdown SGK1. These results provide new insight into the potential role of SGK1 in the pathophysiology of epilepsy.

Research highlights▶ SGK1 mRNA and protein were up-regulated in the brain tissue of patients with drug-refractory epilepsy. ▶ In the rat model, increased expression of SGK1 occurred and went through dynamic alterations. ▶ SGK1 expression was also related with the elevation of EAAT3, which expression reduced after knockdown SGK1.