GSK-3β inhibitor modulates TLR2/NF-κB signaling following myocardial ischemia-reperfusion

The present study defines the expression of Toll-like Receptor 2 (TLR2), and the modulatory role of Glycogen synthase kinase (GSK)-3 beta inhibitor on TLR2/Nuclear Factor-kappa B (NF-kappa B) signaling following myocardial ischemia-reperfusion (MI-R) injury in rats. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to analyze the presence and quantity of TLR2 mRNA and protein. Tumor necrosis factor (TNF)-alpha mRNA and interleukin-6 (IL-6) mRNA were analyzed by RT-PCR. The activation of NF-kappa B was detected by Western Blot and the myocardial infarct size by Evans blue-TTC staining. Following 30 min of myocardial ischemia, a significant up-regulation of TLR2 mRNA was revealed by RT-PCR from 1 to 24 h post reperfusion. IHC demonstrated high protein expression levels of TLR2. Administration of the GSK-3 beta inhibitor 4-benzyl-2-methyl-1, 2, 4-thiadiazolidine-3, 5-dione (TDZD-8) 5 min prior to reperfusion following 1 h reperfusion down-regulated mRNA levels of TLR2 and downstream proinflammatory cytokines (P < 0.05 vs. MI-R), decreased the activity of NF-kappa B and the size of the myocardial infarct (P < 0.05 vs. MI-R). Our results demonstrate that TLR2 and its signaling components are activated by MI-R. TDZD-8 administration attenuates TLR2/NF-kappa B signaling, suggesting a possible mechanism whereby GSK-3 beta inhibition improves the outcome of MI-R.