Hydrogen Sulfide: A Gaseous Mediator and Its Key Role in Programmed Cell Death, Oxidative Stress, Inflammation and Pulmonary Disease.

Hydrogen sulfide (H 2 S) has been acknowledged as a novel gaseous mediator. The metabolism of H 2 S in mammals is tightly controlled and is mainly achieved by many physiological reactions catalyzed by a suite of enzymes. Although the precise actions of H 2 S in regulating programmed cell death, oxidative stress and inflammation are yet to be fully understood, it is becoming increasingly clear that H 2 S is extensively involved in these crucial processes. Since programmed cell death, oxidative stress and inflammation have been demonstrated as three important mechanisms participating in the pathogenesis of various pulmonary diseases, it can be inferred that aberrant H 2 S metabolism also functions as a critical contributor to pulmonary diseases, which has also been extensively investigated. In the meantime, substantial attention has been paid to developing therapeutic approaches targeting H 2 S for pulmonary diseases. In this review, we summarize the cutting-edge knowledge on the metabolism of H 2 S and the relevance of H 2 S to programmed cell death, oxidative stress and inflammation. We also provide an update on the crucial roles played by H 2 S in the pathogenesis of several pulmonary diseases. Finally, we discuss the perspective on targeting H 2 S metabolism in the treatment of pulmonary diseases.