Norbert Weißmann, Akylbek Sydykov, Hermann Kalwa, Ursula Storch, Beate Fuchs, Michael Mederos y Schnitzler, Ralf Brandes, Friedrich Grimminger, Marcel Meissner, Marc Freichel, Stefan Offermanns, Florian Veit, Oleg Pak, Karl-Heinz Krause, Ralph T. Schermuly, Alison C. Brewer, Harald H. H. W. Schmidt, Werner Seeger, Ajay M. Shah, Thomas Gudermann, Hossein A. Ghofrani, Alexander Dietrich
- Lung ischaemia–reperfusion-induced oedema (LIRE) is a life-threatening condition that causes pulmonary oedema induced by endothelial dysfunction. Here we show that lungs from mice lacking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox2y/−) or the classical transient receptor potential channel 6 (TRPC6−/−) are protected from LIR-induced oedema (LIRE). Generation of chimeric mice by bone marrow cell transplantation and endothelial-specific Nox2 deletion showed that endothelial Nox2, but not leukocytic Nox2 or TRPC6, are responsible for LIRE. Lung endothelial cells from Nox2- or TRPC6-deficient mice showed attenuated ischaemia-induced Ca2+ influx, cellular shape changes and impaired barrier function. Production of reactive oxygen species was completely abolished in Nox2y/− cells. A novel mechanistic model comprising endothelial Nox2-derived production of superoxide, activation of phospholipase C-γ, inhibition of diacylglycerol (DAG) kinase, DAG-mediated activation of TRPC6 and ensuing LIRE is supported by pharmacological and molecular evidence. This mechanism highlights novel pharmacological targets for the treatment of LIRE.