Xiamenmycin attenuates hypertrophic scars by suppressing local inflammation and the effects of mechanical stress.

Hypertrophic scarring is a common disease affecting millions of people around the world, but there are currently no satisfactory drugs to treat the disease. Exaggerated inflammation and mechanical stress have been shown to be two main mechanisms of excessive fibrotic diseases. Here we found that a benzopyran natural product, xiamenmycin, could significantly attenuate hypertrophic scar formation in a mechanical stretch-induced mouse model. The compound suppressed local inflammation by reducing CD4+ lymphocyte and monocyte/macrophage retention in fibrotic foci and blocked fibroblast adhesion with monocytes. Both in vivo and in vitro studies found that the compound inhibited the mechanical stress-induced profibrotic effects by suppressing proliferation, activation, fibroblast contraction, and inactivating FAK, p38, and Rho guanosine triphosphatase signaling. Taken together, the compound could simultaneously suppress both the inflammatory and mechanical stress responses, which are the two pivotal pathological processes in hypertrophic scar formation, thus suggesting that xiamenmycin can serve as a potential agent for treating hypertrophic scar formation and other excessive fibrotic diseases.