Attenuation of Staphylococcal enterotoxin-B (SEB)-induced lung injury (ALI) by resveratrol results from miR-193a down-regulation and alterations in metabolic profile

Abstract

Abstract Resveratrol, (RES), a phytoalexin, is well-known for its anti-inflammatory and anti-oxidant properties. SEB, a superantigen, is known to trigger ALI and cause mortality. In the current study, we tested the effect of RES in a dual-dose model of SEB exposure that triggers ALI and causes 100% mortality in C3H/HeJ-mice. The data revealed RES attenuated SEB-induced ALI and prevented mortality. Forty eight hours post-SEB exposure, lung-infiltrating mononuclear cells were tested for microRNA expression profile to determine the epigenetic regulation by resveratrol. SEB-activated splenocytes were pre-treated with 50 μM of RES or vehicle for metabolic profile analysis by measuring oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). We also noted significant decline in miR-193a in the lungs of RES-treated SEB group, which targeted and caused an increase in TGFβ2 and TGFβR3, potent inhibitors of T-cell proliferation, by using RT-PCR and validation by transfection studies. RES-induced downregulation of miR-193a also influenced the activity of mechanistic target of rapamycin (mTOR) as well as pyruvate kinase muscle isozyme2 (PKM2) genes, and caused RES-treated SEB-activated T cells to be quiescent metabolically in comparison to the energetic vehicle-treated SEB-activated T cells. Together, RES caused inhibition in the proliferation of SEB-activated T-cells by alterations in miR expression and metabolic profiles. (Supported by NIH grants P01AT003961, R01AT006888, R01ES019313, R01MH094755, P20GM103641 and R01AI129788).