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

Hydrogen sulfide (HS) has been acknowledged as a novel gaseous mediator. The metabolism of HS in mammals is tightly controlled and is mainly achieved by many physiological reactions catalyzed by a suite of enzymes. Although the precise actions of HS in regulating programmed cell death, oxidative stress and inflammation are yet to be fully understood, it is becoming increasingly clear that HS 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 HS 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 HS for pulmonary diseases. In this review, we summarize the cutting-edge knowledge on the metabolism of HS and the relevance of HS to programmed cell death, oxidative stress and inflammation. We also provide an update on the crucial roles played by HS in the pathogenesis of several pulmonary diseases. Finally, we discuss the perspective on targeting HS metabolism in the treatment of pulmonary diseases.