Oxidant sensor cation channel TRPM2 regulates neutrophil extracellular trap formation and protects against pneumoseptic bacterial infection

Neutrophil extracellular trap (NET) formation constitutes an important extracellular antimicrobial function of neutrophils that plays a protective role in bacterial pneumonia. Formation of reactive oxygen species (ROS) such as highly diffusible hydrogen peroxide (H2O2) is a hallmark of oxidative stress during inflammatory lung conditions including pneumonia. However, the impact of exogenous ROS on NET formation and the signaling pathway involved in the process is not completely understood. Here we demonstrate that the ROS-sensing, nonselective, calcium-permeable channel transient receptor potential melastatin 2 (TRPM2) is required for NET formation in response to exogenous H2O2. This TRPM2-dependent H2O2-mediated NET formation involved components of autophagy and activation of AMPK and p38 MAPK, but not PI3K and AKT. Primary neutrophils from Trpm2−/− mice fail to activate this pathway with a block in NET release and a concomitant decrease in their antimicrobial capacity. Consequently, Trpm2−/− mice were h...