LPS infection augmented ROS accumulation regulates inflammation and apoptosis via Erk1/2MAPK/Akt/NF-κB pathways in keratinocytes after 2-chloroethyl ethyl sulphide challenge

Abstract A monofunctional analog of sulfur mustard, 2-chloroethyl ethyl sulphide (CEES) is a well-known chemical warfare agent that induces vesicles/blisters on cutaneous toxicity in exposed individuals. However, gram-negative bacterial endotoxin lipopolysaccharide (LPS) infection with CEES exposure enhances the keratinocytes injury remains unknown. Here, we investigated the molecular mechanism of LPS infection augmented the reactive oxygen species (ROS) accumulation triggered the expression of inflammatory mediators, leading to membrane damage, disruption of cell-cell comunication and apoptosis via Erk1/2MAPK/Akt/ NF-κB pathways after CEES challenge in keratinocytes. Our results showed that LPS infection with CEES exposure increased the intracellular superoxide (O2•−), hydroxyl radical (OH·) and hydrogen peroxide (H2O2). Further, accumulated ROS activated Erk1/2MAPK, Akt, tuberin-mTOR and NF-κB in keratinocytes. The activated NF-κB stimulates inflammatory mediators, which was subsequently subdued lipids and proteins damage leading to crash the cell-cell communication and apoptosis. Protection against LPS infection with CEES toxicity could also be performed by blocking of ROS accumulation with antioxidant N-acetyl-L-cysteine (NAC) or Erk1/2MAPK or Akt inhibitors, which inhibited the intracellular redox-sensitive signaling pathways, inflammation, cell-cell communication and apoptosis. These results illustrated that accumulated ROS in keratinocyte cells function as a key NF-κB signaling pathway via Erk1/2MAPK/Akt/tuberin-mTOR regulatory signaling cascades induced by CEES exposure after LPS infection, leading to inflammation, loss of cell-cell communication and apoptosis, which was attenuated by antioxidant NAC or Erk1/2MAPK or Akt inhibitors. Moreover, the protective effects of all these inhibitors might provide the basis for the development of a therapeutic strategy to work against exposure to CEES with bacterial endotoxin infection.