Sulfate assimilation regulates hydrogen sulfide production independent of lifespan and reactive oxygen species under methionine restriction condition in yeast

Abstract

Endogenously produced hydrogen sulfide was proposed to be an underlying mechanism of lifespan extension via methionine restriction. However, hydrogen sulfide regulation and its beneficial effects via methionine restriction remain elusive. Here, we identified the genes required to increase hydrogen sulfide production under methionine restriction condition using genome-wide high-throughput screening in yeast strains with single-gene deletions. Sulfate assimilation-related genes, such as MET1 , MET3 , MET5 , and MET10 , were found to be particularly crucial for hydrogen sulfide production. Interestingly, methionine restriction failed to increase hydrogen sulfide production in mutant strains; however, it successfully extended chronological lifespan and reduced reactive oxygen species levels. Altogether, our observations suggested that increased hydrogen sulfide production via methionine restriction is not the mechanism underlying extended yeast lifespan, even though increased hydrogen sulfide production occurred simultaneously with yeast lifespan extension under methionine restriction condition.

On the illusion of auxotrophy:met15Δyeast cells can grow on inorganic sulfur thanks to the previously uncharacterized homocysteine synthase Yll058w

“…We saw consistent results in a bismuth-containing medium lacking organosulfurs (SD-Met-Cys+Glu+Bi; Figure S5A ). In this medium, FY4 and FY4- met15 Δ colonies were darker than in BiGGY ( Figure S5B ), likely resulting from the well-characterized upregulation of the SAP triggered by methionine restriction (8, 14). In contrast, FY4- met3 Δ remained as light as in BiGGY, confirming again that the SAP is disrupted in these cells as expected ( Figure S5B ).…”

“…When Met15 is absent, homocysteine biosynthesis is catalyzed by the comparatively inefficient Yll058w enzyme (right). The resulting lower amount of homocysteine (light green) is sufficient to support growth in some contexts, but the high amount of H 2 S that accumulates (dark gray), exacerbated by an upregulation of the SAP (8, 14), can become toxic and lead to cell death or arrest in other contexts.…”

“…H 2 S levels are extremely high when met15 Δ cells are growing without exogenous organosulfurs ( Figures 2C and S5 ), as a result of the upregulation of the SAP (8, 14) and Yll058w being an inefficient homocysteine synthase. Our results indicate that H 2 S toxicity is at least partially responsible for the arrest and/or death that occurs in met15 Δ cells grown using traditional techniques ( Figure 5 ).…”

Methionine Restriction Improves Gut Barrier Function by Reshaping Diurnal Rhythms of Inflammation-Related Microbes in Aged Mice

“…Additionally, improving aging-related intestinal barrier damage can extend lifespan ( 46 , 47 ). Mechanistically, MR can promote the production of glutathione and regulate the production of H 2 S by activating the nutritional response signal fibroblast growth factor 21, thereby prolonging lifespan and reducing inflammation ( 48 , 49 ). However, some studies have shown that the anti-inflammatory effects of MR are partly independent of these mechanisms ( 50 ).…”

Self-produced hydrogen sulfide improves ethanol fermentation by Saccharomyces cerevisiae and other yeast species

“…Cells were spotted in solid media (3.2% dextrose, 0.4% yeast extract, 0.24% peptone, 0.016% ammonium sulfate, 0.08% lead nitrate, 1.6% agar) and plates were kept at 30°C for 5-7 days. Also, H 2 S production was measured as reported previously [23] with some modifications. BY4742 wt strain were precultured at 30°C with constant shaking for 2 days in fresh YPD media.…”