Interleukin-10 and PD150606 modulate expression of AMPA receptor GluA1 and GluA2 subunits under hypoxic conditions

The goal of this study was to evaluate the effects of anti-inflammatory cytokine, interleukin-10 (IL-10), and calpain inhibitor, PD150606, on the expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits in rat hippocampal slices exposed to repeated brief hypoxic episodes. We studied both individual and combinatory effects of PD150606 and IL-10 on the expression of AMPA receptor subunits under hypoxic conditions for GluA1 and GluA2 as well as their phosphorylated forms - pSer831-GluA1 and pSer880-GluA2. Additionally, we studied whether brief hypoxic episodes and IL-10 may affect mRNA expression of transcriptional factors such as hypoxia-inducible factor-1α and nuclear factor κB (NF-κB). Western blotting analysis of hippocampal slice homogenates revealed that IL-10 and PD150606, both individually and in combination, ameliorate hypoxia-induced decrease in the expression of GluA1 and pSer831-GluA1, with different level of efficiency measured at 10, 50, and 90 min after hypoxia induction. Interestingly, brief hypoxic episodes did not induce any changes in the expression of GluA2 and pSer880-GluA2 subunits, whereas PD150606 showed biphasic effect, decreasing the expression of GluA2 and pSer880-GluA2 at 10 min and potentiating it at 90 min after hypoxia induction. IL-10 alone did not show any effect but was able to reverse PD150606 action on the expression of pSer880-GluA2 at 10 min and further potentiated it for GluA2 at 90 min after hypoxia. Finally, PCR analysis revealed that modulation of GluA1 and GluA2 expressions by hypoxia, and IL-10 was not associated with changes in the expression of hypoxia-inducible factor-1α and nuclear factor-κB (NF-κB) transcriptional factors.