Resveratrol Attenuates Staphylococcus Aureus-Induced Monocyte Adhesion through Downregulating PDGFR/AP-1 Activation in Human Lung Epithelial Cells

Abstract

Staphylococcus aureus (S. aureus) is a very common Gram-positive bacterium. It is widely distributed in air, soil, and water. S. aureus often causes septicemia and pneumonia in patients. In addition, it is considered to play a key role in mediating cell adhesion molecules upregulation. Resveratrol is a natural antioxidant with diverse biological effects, including the modulation of immune function, anti-inflammation, and cancer chemoprevention. In this study, we proved that S. aureus-upregulated vascular cell adhesion molecule-1 (VCAM-1) expression in human lung epithelial cells (HPAEpiCs) was inhibited by resveratrol. We also observed that resveratrol downregulated S. aureus-enhanced leukocyte count in bronchoalveolar lavage (BAL) fluid in mice. In HPAEpiCs, S. aureus stimulated c-Src, PDGFR, p38 MAPK, or JNK1/2 phosphorylation, which was inhibited by resveratrol. S. aureus induced the adhesion of THP-1 cells (a human monocytic cell line) to HPAEpiCs, which was also reduced by resveratrol. Finally, we found that S. aureus induced c-Src/PDGFR/p38 MAPK and JNK1/2-dependent c-Jun and ATF2 activation and in vivo binding of c-Jun and ATF2 to the VCAM-1 promoter, which were inhibited by resveratrol. Thus, resveratrol functions as a suppressor of S. aureus-induced inflammatory signaling, not only by inhibiting VCAM-1 expression but also by diminishing c-Src, PDGFR, JNK1/2, p38 MAPK, and AP-1 activation in HPAEpiCs.