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H₂O₂-Mediated Oxidative Stress Enhances Cystathionine γ-Lyase-Derived H₂S Synthesis via a Sulfenic Acid Intermediate.

ABSTRACT: Hydrogen sulfide (H₂S), which is generated mainly by cystathionine γ-lyase (CSE) in the cardiovascular system, plays a pivotal role in a wide range of physiological and pathological processes. However, the regulatory mechanism of the CSE/H₂S system is poorly understood. Herein, we show that oxidation induces the disulfide bond formation between Cys252 and Cys255 in the CXXC motif, thus stimulating the H₂S-producing activity of CSE. The activity of oxidized CSE is approximately 2.5 fold greater than that of the reduced enzyme. Molecular dynamics and molecular docking suggest that the disulfide bond formation induces the conformational change in the active site of CSE and consequently increases the affinity of the enzyme for the substrate L-cysteine. Mass spectrometry and mutagenesis studies further established that the residue Cys255 is crucial for oxidation sensing. Oxidative stress-mediated sulfenylation of Cys255 leads to a sulfenic acid intermediate that spontaneously forms an intramolecular disulfide bond with the vicinal thiol group of Cys252. Moreover, we demonstrate that exogenous hydrogen peroxide (H₂O₂) and endogenous H₂O₂ triggered by vascular endothelial growth factor (VEGF) promote cellular H₂S production through the enhancement of CSE activity under oxidative stress conditions. By contrast, incubation with H₂O₂ or VEGF did not significantly enhance cellular H₂S production in the presence of PEG-catalase, an enzymatic cell-permeable H₂O₂ scavenger with high H₂O₂ specificity. Taken together, we report a new posttranslational modification of CSE that provides a molecular mechanism for H₂O₂/H₂S crosstalk in cells under oxidative stress.

SUBMITTER: Wang J

PROVIDER: S-EPMC8466214 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundHydrogen sulfide (H(2)S) is a potent vasodilator. However, the complex mechanisms of vasoregulation by H(2)S are not fully understood. We tested the hypotheses that (1) H(2)S exerts vasodilatory effects by opening KCNQ-type voltage-dependent (K(v)) K(+) channels and (2) that H(2)S-producing cystathionine-γ-lyase (CSE) in perivascular adipose tissue plays a major role in this pathway.Methodology/principal findingsWire myography of rat and mouse aortas was used. NaHS and 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADTOH) were used as H(2)S donors. KCNQ-type K(v) channels were blocked by XE991. 4-Propargylglycine (PPG) and ß-cyano-l-alanine (BCA), or 2-(aminooxy)-acetic acid (AOAA) were used as inhibitors of CSE or cystathionine-ß-synthase (CBS), respectively. NaHS and ADTOH produced strong vasorelaxation in rat and mouse aortas, which were abolished by KCNQ channel inhibition with XE991. Perivascular adipose tissue (PVAT) exerted an anticontractile effect in these arteries. CSE inhibition by PPG and BCA reduced this effect in aortas from rats but not from mice. CBS inhibition with AOAA did not inhibit the anticontractile effects of PVAT. XE991, however, almost completely suppressed the anticontractile effects of PVAT in both species. Exogenous l-cysteine, substrate for the endogenous production of H(2)S, induced vasorelaxation only at concentrations >5 mmol/l, an effect unchanged by CSE inhibition.Conclusions/signficanceOur results demonstrate potent vasorelaxant effects of H(2)S donors in large arteries of both rats and mice, in which XE991-sensitive KCNQ-type channel opening play a pivotal role. CSE-H(2)S seems to modulate the effect of adipocyte-derived relaxing factor in rat but not in mouse aorta. The present study provides novel insight into the interaction of CSE-H(2)S and perivascular adipose tissue. Furthermore, with additional technical advances, a future clinical approach targeting vascular H(2)S/KCNQ pathways to influence states of vascular dysfunction may be possible.

Project description:Hydrogen sulfide (H2S) has recently been recognized as a novel gaseous transmitter with several anti-inflammatory properties. The role of host- derived H2S in infections by Pseudomonas aeruginosa was investigated in clinical and mouse models. H2S concentrations and survival was assessed in septic patients with lung infection. Animal experiments using a model of severe systemic multidrug-resistant P. aeruginosa infection were performed using mice with a constitutive knock-out of cystathionine-γ lyase (Cse) gene (Cse-/-) and wild-type mice with a physiological expression (Cse+/+). Experiments were repeated in mice after a) treatment with cyclophosphamide; b) bone marrow transplantation (BMT) from a Cse+/+ donor; c) treatment with H2S synthesis inhibitor aminooxyacetic acid (ΑΟΑΑ) or propargylglycine (PAG) and d) H2S donor sodium thiosulfate (STS) or GYY3147. Bacterial loads and myeloperoxidase activity were measured in tissue samples. The expression of quorum sensing genes (QS) was determined in vivo and in vitro. Cytokine concentration was measured in serum and incubated splenocytes. Patients survivors at day 28 had significantly higher serum H2S compared to non-survivors. A cut- off point of 5.3 μΜ discriminated survivors with sensitivity 92.3%. Mortality after 28 days was 30.9% and 93.7% in patients with H2S higher and less than 5.3 μΜ (p = 7 x 10-6). In mice expression of Cse and application of STS afforded protection against infection with multidrug-resistant P. aeruginosa. Cyclophosphamide pretreatment eliminated the survival benefit of Cse+/+ mice, whereas BMT increased the survival of Cse-/- mice. Cse-/- mice had increased pathogen loads compared to Cse+/+ mice. Phagocytic activity of leukocytes from Cse-/- mice was reduced but was restored after H2S supplementation. An H2S dependent down- regulation of quorum sensing genes of P.aeruginosa could be demonstrated in vivo and in vitro. Endogenous H2S is a potential independent parameter correlating with the outcome of P. aeruginosa. H2S provides resistance to infection by MDR bacterial pathogens.

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H₂O₂-Mediated Oxidative Stress Enhances Cystathionine γ-Lyase-Derived H₂S Synthesis via a Sulfenic Acid Intermediate.

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H2O2-Mediated Oxidative Stress Enhances Cystathionine γ-Lyase-Derived H2S Synthesis via a Sulfenic Acid Intermediate.

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OmicsDI is part of the ELIXIR infrastructure

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H₂O₂-Mediated Oxidative Stress Enhances Cystathionine γ-Lyase-Derived H₂S Synthesis via a Sulfenic Acid Intermediate.