Photoactivated resveratrol controls intradermal infection by Staphylococcus aureus in mice: a pilot study.

Staphylococcus aureus is one of the main causative agent of infections acquired in both community and hospital environment. In this context, photodynamic therapy (PDT) consists in using a photosensitizer that, activated by light, evokes the formation of reactive oxygen species (ROS), which lead to the death of microorganisms due to oxidative damage; it is useful tool since this action, harmful to pathogens, does not significantly injure human cells. In view of this, this work proposes a more in-depth study on the use of resveratrol (RSV) as a possible photosensitizer. It was observed, in the intradermal infection model in animals' ear dermis, that photoactivated resveratrol promotes an increase in myeloperoxidase expression with reduced bacterial load in the draining lymph node. Besides that, the draining lymph node of the animals treated with photoactivated RSV controls inflammation through IL-10 production. These are pioneers data and this work being a pilot study; then, other works must be conducted with the objective of elucidate the photoactivated resveratrol mechanism of action.

RM, a novel resveratrol derivative, attenuates inflammatory responses induced by lipopolysaccharide via selectively increasing the Tollip protein in macrophages: A partial mechanism with therapeutic potential in an inflammatory setting.

Although the novel resveratrol derivative RM has therapeutic potential for the treatment of inflammatory bowel disease, little is currently known regarding the manner whereby RM regulates excessive inflammatory responses. In this study, we initially investigated the molecular mechanisms underlying the anti-inflammatory effects induced by RM in Toll-like receptor (TLR)-activated macrophages. Upon stimulation with lipopolysaccharide, we found that RM-treated activated macrophages down-regulated the increase in pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß, and IL-12p70), nitric oxide (NO) production, and activating interleukin-1 receptor-associated kinase 1 (IRAK-1) phosphorylation, mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. Interestingly, the TLR negative regulator Toll-interacting protein (Tollip) was selectively enhanced during RM stimulation in time- and dose-dependent manners. In response to knockdown of Tollip expression by RNA interference, RM-treated activated macrophages showed augmented expression of inflammatory mediators (pro-inflammatory cytokines, NO, inducible nitric oxidase, and cyclooxygenase-2, and surface molecules) and restored the expression of MAPK and NF-κB signals inhibited by RM treatment. Taken together, our findings indicate that RM has therapeutic potential for treating TLR-induced inflammatory diseases via the promotion of Tollip expression.