Fig. 1.
The proposed pathways underlying the protective roles of hydrogen sulfide (H2S) against COVID-19. H2S as a novel gasotransmitter regulates a variety of physiological functions and provides protection against organ damages (box 1). H2S also displays beneficial roles in preventing lung disorders (box 2) and viral replication (box 3). Cystathionine-γ-lyase (CSE)-derived H2S (box 4) or exogenously applied H2S may block severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into the host cells by interrupting angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2), inhibit virus replication by attenuating syncytium formation and virus assembly/release, and protect SARS-CoV-2-induced lung damage by suppressing the immune response and inflammation development. The dotted line indicates the prediction, and the red line means the blockage of the pathway. CVB3, coxsackie virus B3; PPG, dl-propargylglycine; RSV, respiratory syncytial virus.