Hydrogen Sulfide Upregulates Glutamate–Cysteine Ligase Catalytic Subunit, Glutamate–Cysteine Ligase Modifier Subunit, and Glutathione and Inhibits Interleukin-1β Secretion in Monocytes Exposed to High Glucose Levels

Abstract

Glutathione (GSH) deficiency and interleukin-1β (IL-1β) upregulation are linked to the progression of vascular inflammation and atherosclerosis. The consumption of sulfide-rich vegetables is known to lower the risk of atherosclerosis. This study examined the hypothesis that hydrogen sulfide (H2S) upregulates the glutamate-cysteine ligase catalytic subunit (GCLC) and GSH and inhibits IL-1β in a monocyte cell model. U937 monocytes were supplemented with H2S (0-12.5 μM) for 2 hr and then exposed to a control or high glucose (HG, 25 mM) for 22 hr. Levels of GCLC and glutamate-cysteine ligase modifier subunit (GCLM) expression were determined by western blotting and GSH using high-performance liquid chromatography (HPLC), and IL-1β using enzyme-linked immunoassay (ELISA). H2S significantly (P<0.05) upregulated expression of GCLC and GCLM, and formation of GSH, and inhibited IL-1β secretion in controls and HG-treated monocytes. This is the first demonstration of H2S upregulation of GCLC and GSH and inhibition of IL-1β levels, which may be what mediates the beneficial effects of H2S-rich compounds in mitigating the pathogenesis of metabolic syndrome and atherosclerosis.