Hydrogen sulphide: a novel inhibitor of hypochlorous acid-mediated oxidative damage in the brain?
journal contribution
posted on 2023-05-17, 01:42authored byWhiteman, M, Cheung, NS, Zhu, YZ, Chu, SH, Siau, JL, Wong, BS, Armstrong, JS, Moore, PK
Hydrogen sulphide (H2S) is a cytotoxic gas that has recently been proposed as a novel neuromodulator. Endogenous levels of H2S in the brain range between 50 and 160 ìM, and considerably lower H2S levels are reported in the brains of Alzheimer's disease (AD) patients. Levels of myeloperoxidase (MPO), an enzyme that catalyses the formation of the oxidant hypochlorous acid (HOCl), are elevated in the prefrontal cortex, hippocampal microglia, and neurons of AD patients where MPO co-localised with â-amyloid plaques. Recently 3-chlorotyrosine, a bio-marker for MPO activity (and HOCl production), was shown to be elevated threefold in hippocampal proteins from AD patients. Since H2S and HOCl are important mediators in brain function and disease, we investigated the effects of H2S on HOCl-mediated damage to bio-molecules and to cultured human SH-SY5Y cells. H2S significantly inhibited HOCl-mediated inactivation of á1-antiproteinase and protein oxidation to a comparable extent to reduced glutathione. H2S also inhibited HOCl-induced cytotoxicity, intracellular protein oxidation, and lipid peroxidation in SH-SY5Y cells. These data suggest that H2S has the potential to act as an inhibitor of HOCl-mediated processes in vivo and that the potential antioxidant action of H2S deserves further study, especially since extracellular GSH levels in the brain are very low.
History
Publication title
Biochemical and Biophysical Research Communications
Volume
326
Issue
4
Pagination
794-798
ISSN
0006-291X
Department/School
Menzies Institute for Medical Research
Publisher
Academic Press Inc Elsevier Science
Place of publication
525 B St, Ste 1900, San Diego, USA, Ca, 92101-4495