Oxidative Stress-Dependent Conversion of Hydrogen Sulfide to Sulfite by Activated Neutrophils

Abstract

Sulfite, which is known as a major constituent of volcanic gas, is endogenously produced in mammals, and its concentration in serum is increased in patients with pneumonia. It has been reported that sulfite is produced by oxidation from hydrogen sulfide (H2S) as an intermediate in the mammalian body. The objective of this study was to investigate the ability of reactive oxygen species from neutrophils to produce sulfite from H2S. Sulfite production from activated neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine gradually increased with an increased concentration of sodium hydrosulfide (NaHS) in the medium. The production of sulfite was markedly suppressed with an NADPH oxidase inhibitor, diphenyleneiodonium. When NaHS was added to the supernatant of activated neutrophils, a significant amount of sulfite was synthesized in the test tubes. Furthermore, when a medium containing NaHS was incubated with a water-soluble radical initiator, 2,2'-azobis-(amidinopropane) dihydrochloride, sulfite was formed in the solution and this increase was markedly suppressed by ascorbic acid. Finally, we determined serum concentrations of sulfite and H2S in an in vivo model of neutrophil activation induced by systemic injection of lipopolysaccharide (LPS) into rats. We found a significant increase in serum sulfite and H2S after LPS injection. Importantly, coadministration of ascorbic acid with LPS further increased serum H2S but suppressed sulfite levels. This finding implies that oxidative stress-dependent conversion of H2S to sulfite might occur in vivo. Thus, the oxidation of H2S is a novel sulfite production pathway in the inflammatory condition, and this chemical synthesis might be responsible for the upregulation of sulfite production in inflammatory conditions such as pneumonia.

Hydrogen Sulfide Regulates Cardiac Function and Structure in Adriamycin-Induced Cardiomyopathy

“…28,29 Moreover, H2S is a highly reactive molecule and may easily react with other compounds, especially ROS and reactive nitrogen species (RNS). Indeed, H2S reacts with at least 4 different ROS 30 [superoxide radical anion, H2O2, peroxynitrite, 31 and hypochlorite 32 ]. All these compounds are highly reactive and their interaction with H2S results in the protection of proteins and lipids against ROS/RNS-mediated damage.…”

Effect of Sodium Metabisulphite on Blood Metabolic Status of Wistar Rats

“…They can also be generated by polymorphonuclear neutrophils [3]. Several mammalian cells produce sulphites from H 2 S [4]. Exogenous sources of sulphites include food, drinks, ambient air and pharmaceutical products [5].…”

Genetics and pathophysiology of mammalian sulfate biology

“…The latter pathway generates hydrogen sulfide from cysteine via CBS, either in the cytosol or mitochondria, which is then oxidized via SQRDL and TST in the mitochondria (Olson, 2015). Hydrogen sulfide can also be converted to sulfur dioxide, via nicotinamide-adenine dinucleotide phosphate oxidase (Mitsuhashi et al, 2005), which is further converted to sulfite and sulfate (Fig. 1B).…”