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Aims: The physiological and pathological importance of hydrogen sulfide (H2S) as a novel gasotransmitter has been widely recognized. Cystathionine gamma-lyase (CSE) is one of the major H2S-producing enzymes and it regulates diverse functions in connection with intracellular calcium (Ca2+). The aim of this study is to examine the role of H2S in Golgi stress-related cell injury and skeletal muscle disorders. Results: Golgi stressors (brefeldin A [BFA] and monensin) decreased the expression of GM130 and ATP2C1 (two markers of Golgi stress response), induced Golgi apparatus fragmentation, and caused a higher level of oxidative stress and cell apoptosis in mouse myoblast cells. In addition, Golgi stressors upregulated CSE expression and endogenous H2S generation, and exogenously applied H2S was able to protect but inhibition of CSE/H2S system deteriorated Golgi stress response. Activating transcription factor 4 (ATF4) acted as an upstream molecule to increase CSE expression on Golgi stress response. Mechanically, Golgi stressors induced intracellular level of Ca2+, and chelating cellular Ca2+ markedly attenuated Golgi stress response, indicating the key role of Ca2+ in initiating Golgi stress and cell apoptosis. Further, administration of either angiotensin II or BFA initiated Golgi stress response and induced skeletal muscle atrophy in mice, which was further deteriorated by CSE deficiency but rescued by exogenously applied sodium hydrosulfide (NaHS). Innovation and Conclusion: The activation of the CSE/H2S pathway and the decrease of intracellular Ca2+ are two cellular protective mechanisms against Golgi stress, and the CSE/H2S system would be a target for preventing skeletal muscle dysfunctions.

Aims: Endothelium-dependent vasorelaxation is mediated by endothelium-derived relaxing factor and endothelium-derived hyperpolarizing factor (EDHF). However, the molecular entity of EDHF remains unclear. The present study examined whether hydrogen sulfide (H2S) acts as EDHF and how H2S mediates EDHF pathways from endothelial origination to downstream target of smooth muscle cells (SMCs). Results: We found that knocking-out the expression of cystathionine γ-lyase (CSE) in mice (CSE-knockout [KO]) elevated resting-membrane-potential of SMCs and eliminated methacholine-induced endothelium-dependent relaxation of mesenteric arteries, but not that of aorta. Methacholine, a cholinergic-muscarinic agonist, hyperpolarized SMC in endothelium-intact mesenteric arteries from wide-type mice. This effect was inhibited by muscarinic antagonist (atropine) or the co-application of charybdotoxin and apamin, which blocked intermediate- and small-conductance KCa (IKCa and SKCa) channels, or abolished in CSE-KO mice...

H2S, a third member of gasotransmitter family along with nitric oxide and carbon monoxide, exerts a wide range of cellular and molecular actions in our body. Cystathionine gamma-lyase (CSE) is a major H2S-generating enzyme in our body. Aging at the cellular level, known as cellular senescence, can result from increases in oxidative stress. The aim of this study was to investigate how H2S attenuates oxidative stress and delays cellular senescence.Here we showed that mouse embryonic fibroblasts isolated from CSE knockout mice (CSE KO-MEFs) display increased oxidative stress and accelerated cellular senescence in comparison with MEFs from wild-type mice (WT-MEFs). The protein expression of p53 and p21 was significantly increased in KO-MEFs, and knockdown of p53 or p21 reversed CSE deficiency-induced senescence. Incubation of the cells with NaHS (a H2S donor) significantly increased the glutathione (GSH) level and rescued KO-MEFs from senescence. Nrf2 is a master regulator of the antioxidant response, and Keap1 acts as a negative regulator of Nrf2. NaHS S-sulfhydrated Keap1 at cysteine-151, induced Nrf2 dissociation from Keap1, enhanced Nrf2 nuclear translocation, and stimulated mRNA expression of Nrf2-targeted downstream genes, such as glutamate-cysteine ligase and GSH reductase.These results provide a mechanistic insight into how H2S signaling mediates cellular senescence induced by oxidative stress.H2S protects against cellular aging via S-sulfhydration of Keap1 and Nrf2 activation in association with oxidative stress.

Butyrate is a short-chain fatty acid that arrests growth of various types of cells. H(2)S can be endogenously produced by cystathionine gamma-lyase (CSE) or cystathionine beta-synthase (CBS) or both in colonic tissues. In this study, we observed endogenous H(2)S production in a colon cancer cell line (WiDr) and colonic tissues through the activity of both CSE and CBS. After 24 h of incubation of WiDr cells, butyrate increased cell production of H(2)S and upregulated CBS and CSE expressions. Both butyrate and NaHS (a H(2)S donor) decreased cell viability in a dose-dependent manner. Blockade of CBS, but not CSE, decreased butyrate-stimulated H(2)S production and reversed butyrate-inhibited cell viability. In addition, NaHS treatment stimulated the phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal kinase (JNK). Inhibition of the phosphorylation of either p38 MAPK or ERK did not abolish NaHS-induced cell death. Butyrate treatment increased the phosphorylation of ERK, not p38 MAPK and JNK, but inhibition of ERK and p38 MAPK phosphorylation did not inhibit butyrate-reduced cell viability. In conclusion, butyrate regulates endogenous H(2)S production by stimulating CBS expression in colon cancer cells, but butyrate and H(2)S inhibit cancer cell growth through different mechanisms.