PNPO–PLP axis senses prolonged hypoxia in macrophages by regulating lysosomal activity

Hypoxic responses such as hypoxia-inducible factor pathways, have been implicated in a variety of physiological and pathological conditions. However, how oxidases make contributions to oxygen sensing and response to hypoxia is not fully understood. In this study, the authors showed that pyridoxine 5′-phosphate oxidase (PNPO), which catalyses bioactivation of vitamin B6, serves as an oxygen sensor and regulates lysosomal activity in macrophages, thereby altering inflammatory response.