The role of hydrogen sulphide signalling in macrophage activation

Hydrogen sulphide (H₂ S) is the latest identified small gaseous mediator enabled by its lipophilic nature to freely permeate the biological membranes. Initially, H₂ S was recognized by its roles in neuronal activity and vascular relaxation, which makes it an important molecule involved in paracrine signalling pathways. Recently, the immune regulatory function of gasotransmitters, H₂ S in particular, is increasingly being appreciated. Endogenous H₂ S level has been linked to macrophage activation, polarization and inflammasome formation. Mechanistically, H₂ S-induced protein S-sulphydration suppresses several inflammatory pathways including NF-κB and JNK signalling. Moreover, H₂ S serves as a potent cellular redox regulator to modulate epigenetic alterations and to promote mitochondrial biogenesis in macrophages. Here in this review, we intend to summarize the recent advancements of H₂ S studies in macrophages, and to discuss with focus on the therapeutic potential of H₂ S donors by targeting macrophages. The feasibility of H₂ S signalling component as a macrophage biomarker under disease conditions would be also discussed.