Targeting mitochondria with methylene blue protects mice against acetaminophen‐induced liver injury

Acetaminophen (APAP) overdose is a frequent cause of drug‐induced liver injury and the most frequent cause of acute liver failure in the Western world. Previous studies with mouse models have revealed that impairment of mitochondrial respiration is an early event in the pathogenesis, but the exact mechanisms have remained unclear, and therapeutic approaches to specifically target mitochondria have been insufficiently explored. Here, we found that the reactive oxidative metabolite of APAP, N‐acetyl‐p‐benzoquinoneimine (NAPQI), caused the selective inhibition of mitochondrial complex II activity by >90% in both mouse hepatic mitochondria and yeast‐derived complexes reconstituted into nanoscale model membranes, as well as the decrease of succinate‐driven adenosine triphosphate (ATP) biosynthesis rates. Based on these findings, we hypothesized that methylene blue (MB), a mitochondria‐permeant redox‐active compound that can act as an alternative electron carrier, protects against APAP‐induced hepatocyte injury. We found that MB (