{"doi":"10.1016/j.jbc.2021.100736","title":"The mitochondrial NADH pool is involved in hydrogen sulfide signaling and stimulation of aerobic glycolysis","abstract":"Hydrogen sulfide is synthesized by enzymes involved in sulfur metabolism and oxidized via a dedicated mitochondrial pathway that intersects with the electron transport chain at the level of complex III. Studies with H2S are challenging since it is volatile and also reacts with oxidized thiols in the culture medium, forming sulfane sulfur species. The half-life of exogenously added H2S to cultured cells is unknown. In this study, we first examined the half-life of exogenously added H2S to human colonic epithelial cells. In plate cultures, H2S disappeared with a t1/2 of 3 to 4 min at 37 °C with a small fraction being trapped as sulfane sulfur species. In suspension cultures, the rate of abiotic loss of H2S was slower, and we demonstrated that sulfide stimulated aerobic glycolysis, which was sensitive to the mitochondrial but not the cytoplasmic NADH pool. Oxidation of mitochondrial NADH using the genetically encoded mito-LbNOX tool blunted the cellular sensitivity to sulfide-stimulated aerobic glycolysis and enhanced its oxidation to thiosulfate. In contrast, sulfide did not affect flux through the oxidative pentose phosphate pathway or the TCA cycle. Knockdown of sulfide quinone oxidoreductase, which commits H2S to oxidation, sensitized cells to sulfide-stimulated aerobic glycolysis. Finally, we observed that sulfide decreased ATP levels in cells. The dual potential of H2S to activate oxidative phosphorylation at low concentrations, but inhibit it at high concentrations, suggests that it might play a role in tuning electron flux and, therefore, cellular energy metabolism, particularly during cell proliferation. Hydrogen sulfide is synthesized by enzymes involved in sulfur metabolism and oxidized via a dedicated mitochondrial pathway that intersects with the electron transport chain at the level of complex III. Studies with H2S are challenging since it is volatile and also reacts with oxidized thiols in the culture medium, forming sulfane sulfur species. The half-life of exogenously added H2S to cultured cells is unknown. In this study, we first examined the half-life of exogenously added H2S to human colonic epithelial cells. In plate cultures, H2S disappeared with a t1/2 of 3 to 4 min at 37 °C with a small fraction being trapped as sulfane sulfur species. In suspension cultures, the rate of abiotic loss of H2S was slower, and we demonstrated that sulfide stimulated aerobic glycolysis, which was sensitive to the mitochondrial but not the cytoplasmic NADH pool. Oxidation of mitochondrial NADH using the genetically encoded mito-LbNOX tool blunted the cellular sensitivity to sulfide-stimulated aerobic glycolysis and enhanced its oxidation to thiosulfate. In contrast, sulfide did not affect flux through the oxidative pentose phosphate pathway or the TCA cycle. Knockdown of sulfide quinone oxidoreductase, which commits H2S to oxidation, sensitized cells to sulfide-stimulated aerobic glycolysis. Finally, we observed that sulfide decreased ATP levels in cells. The dual potential of H2S to activate oxidative phosphorylation at low concentrations, but inhibit it at high concentrations, suggests that it might play a role in tuning electron flux and, therefore, cellular energy metabolism, particularly during cell proliferation. In contrast to most quiescent cells that rely on the efficiency of oxidative phosphorylation to harvest energy from glucose catabolism, rapidly dividing cells dial up glycolytic flux in a process referred to as the Warburg effect (1Warburg O. Posener K. Negelein E. On the metabolism of carcinoma cells.Biochem. Z. 1924; 152: 309-344Google Scholar). This metabolic switching is cued in part by growth factors and transforms mitochondria into central hubs for macromolecule precursor synthesis (2Ward P.S. Thompson C.B. Metabolic reprogramming: A cancer hallmark even Warburg did not anticipate.Cancer Cell. 2012; 21: 297-308Abstract Full Text Full Text PDF PubMed Scopus (1869) Google Scholar). In this metabolically reprogr","journal":"Journal of Biological Chemistry","year":2021,"id":162226,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":49,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9456,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2021-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":31917,"name":"Roshan Kumar","orcid":"0000-0002-5372-8682","position":1,"is_corresponding":false},{"id":678647,"name":"Marouane Libiad","orcid":"0000-0003-1717-9206","position":2,"is_corresponding":false},{"id":678648,"name":"Allison Maebius","orcid":"0000-0002-2384-2978","position":3,"is_corresponding":false},{"id":265992,"name":"Aaron P. Landry","orcid":"0000-0003-1161-7092","position":4,"is_corresponding":false},{"id":265994,"name":"Ruma Banerjee","orcid":"0000-0001-8332-3275","position":5,"is_corresponding":false},{"id":350208,"name":"Victor Vitvitsky","orcid":"0000-0001-6251-6115","position":0,"is_corresponding":true}],"reference_count":45,"raw_metadata":null,"created_at":"2026-07-18T23:45:00.600065Z","pmid":"33933447","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}