Interaction Of H2S Research Articles

In Vitro Measurement of H2S-Mediated Vasoactive Responses.

Isolated tissue chamber bath system and wire myograph were developed for "in vitro" investigation of vasoactive responses on isolated arteries from a variety of animal species and vascular beds. The chapter characterizes the main principles of mechanical measurement of the changes in isometric tension of vascular smooth muscles in isolated rat thoracic aorta and superior mesenteric artery and describes several protocols on how to investigate vasoactive properties of hydrogen sulfide (H2S) from the point of view of its mutual interaction with NO. Several methodological advances, results, and their interpretations in the context of the general knowledge are described. In the protocols the approach on how to study the vasoactive modulatory as well as direct action of H2S and mutual interaction of H2S with nitroso compounds, lipids, and endogenously produced NO is described.

A two-photon ratiometric probe for hydrogen polysulfide (H2Sn): Increase in mitochondrial H2Sn production in a Parkinson’s disease model

Hydrogen polysulfide (H2Sn, n>1), which is primarily generated during the crosstalk between H2S and reactive species (ROS and RNS), is receiving increasing attention in biochemical research. H2Sn is mostly generated in the mitochondria, and abnormal mitochondrial function and oxidative stress are directly related to many disorders including Parkinson's disease (PD). We now report a two-photon fluorescent probe (SPS-M1) for in situ detection of H2Sn and its application to a PD model to account the H2Sn levels. The probe exhibited selective and fast response to H2Sn along with a marked blue-to-green color change. SPS-M1 is sensitive enough to quantitative detection of endogenous H2Sn content in mitochondria using two-photon microscopy (TPM). Ratiometric TPM imaging of live neurons and brain slices using SPS-M1 revealed that H2Sn production is increased to a greater extent in the A53 T α-synuclein (α-syn) overexpressing model than in the wild-type control. These findings suggest that the interactions of H2S and the increased ROS caused by α-syn overexpression may generate more H2Sn. By employing our recently published TP probe for mitochondrial H2S, we also found the relationship between the H2Sn and H2S; increased H2Sn and decreased H2S levels, indicating that H2S and H2Sn may play a significant role in the pathogenesis of PD. This result may be useful to biomedical studies, including PD.

Novel asphaltene-derived nanoporous carbon with N-S-rich micro-mesoporous structure for superior gas adsorption: Experimental and DFT study

The development of waste-derived nanoporous carbon, especially from petroleum wastes, as a challenging type of contaminants, has drawn tremendous attention during the past decade. In this work, for the first time, a novel N-S-rich nanoporous carbon possessing high value-added and porosity, was prepared from asphaltene residue through a simple chemical activation. After carbonization of the precursor at 450 °C, chemical activation by different KOH/C ratios (2:1 to 5:1 g/g) was followed which resulted in the formation of unique micro-mesoporous structures (named as IANC samples). The results displayed that large surface area (up to 2186 m2/g) and pore volume (up to 1.3 cm3/g) were obtained. The IANC samples showed outstanding CO2 and H2S uptake at both atmospheric (7.15 mmol/g for CO2 and 12.86 mmol/g for H2S at 1 bar and 25 °C) and high pressures (29.29 mmol/g for CO2 and 38.61 mmol/g for H2S at 35 bar and 25 °C). Furthermore, the IANCs exhibited excellent selectivity for CO2/CH4, H2S/CH4 and CO2/N2 samples. To better understand the interactions mechanism between adsorbent and each adsorbed molecule and also to determine the active sites in the adsorption process, the density functional theory (DFT) method was employed. The quantum chemistry calculations elucidated the exciting impact of defected nitrogen and sulfur sites in enhancing adsorption interaction of H2S and CO2. Besides the fascinating gas uptake and the preferential gas adsorption, the synthesized IANCs possessed high heat of adsorption and stable cyclic adsorption-desorption ability. Considering the inexpensive cost of asphaltene along with the desired adsorption properties, the asphaltene-derived activated nanoporous carbon (i.e., IANC) can be a promising candidate for superior gas adsorption.

Interaction between Hydrogen Sulfide and Muscarinic Receptors in the Regulation of Contractility of the Mouse Atrium

Hydrogen sulfide (H2S) is an endogenously synthesized gaseous transmitter that participates in the regulation of the cardiovascular system and has a cardioprotective effect under ischemia–reperfusion conditions. Here, we studied possible mechanisms of the interaction of H2S and muscarinic acetylcholine receptors in the regulation of mice atrium contractility in the isometric conditions. We show that sodium hydrosulfide (NaHS), an exogenous donor of H2S, caused dose-dependent and reversible depression of the contractile force in the concentration range from 1 μM to 5 mM. The negative inotropic effect of NaHS did not change after the activation of muscarinic acetylcholine receptors by carbachol. However, we observed that the negative inotropic effect of carbachol increased after preliminary application of NaHS. The application of the reducing agent dithiothreitol did not change the effects of carbachol, which indicated that the effects of NaHS was not related to a direct action on the disulfide bonds of the receptor’s protein subunits. The increased effects of carbachol after NaHS application were not prevented by the inhibition of intracellular signaling pathway that mediated activation of M-cholinergic receptors, including adenylate cyclase, guanylate cyclase, and NO-synthase. However, an increase in the carbachol negative inotropic effect was not observed when ATP-dependent potassium channels were inhibited by glibenclamide. In its turn, activation of ATPdependent potassium channels by diazoxide resulted in an increase in carbachol negative inotropic action in the atrial myocardium of mice similar to the effect of NaHS. Our data indicate that the enhanced negative inotropic effect of carbachol under the action of H2S in the mouse atrium was mediated by the activation of ATP-dependent potassium channels.

Partitioning of arsenic between hydrothermal fluid and pyrite during experimental siderite replacement

Arsenian pyrite is the major host mineral of gold in Carlin type gold deposit (CTGD) and forms during the interaction of H2S bearing hydrothermal fluids with Fe-bearing carbonates (e.g., siderite, ankerite, Fe-rich dolomite) in the wall rock. Experimental replacement of siderite at hydrothermal conditions (i.e., 200 °C, Psat) was used to study the parameters that control the formation of CTGD pyrite (i.e., pH, time, aH2S) and the partitioning of As between the hydrothermal fluid and newly formed pyrite.Hydrothermal pyrite formed via replacement of siderite in experiments mainly occurs as two types: 1) porous, massive pyrite at alkaline pH conditions or 2) clusters of dense euhedral to anhedral pyrite grains at slightly acidic conditions (pH <6). Longer experimental run times (2 weeks) lead to formation of type 2 pyrite at alkaline conditions and an increase in euhedral grain sizes in all conditions.Concentration of As in newly formed pyrite depends strongly on the As concentration of the hydrothermal fluid used in the experiment. Calculated partition coefficients vary between 300 and 1700 with lowest D values at high As concentrations of the fluid. In the studied system As−1 substitutes for S−2 as indicated by the correlation of high As with low S concentrations. Experimental findings agree well with previous studies in natural CTGD on As substitution and the partitioning of As between ore stage pyrite and hydrothermal fluids trapped as fluid inclusions.The newly constrained partition coefficients for As help to explain the large heterogeneity in natural CTGD pyrite compositions which is caused by changes in the fluid composition due to the strong partitioning of As into the forming pyrite.

On the Significance of Lone Pair/Lone Pair and Lone Pair/Bond Pair Repulsions in the Cation Affinity and Lewis Acid/Lewis Base Interactions.

Interaction of H2O, H2S, H2Se, NH3, PH3, and AsH3 with cations H+, CH3+, Cu+, Al+, Li+, Na+, and K+ was studied from the energetic and structural viewpoint using B3LYP/6-311++G(d,p) method. The charge transfer from the Lewis bases to the cations reduces lone pair/lone pair (LP/LP) repulsion in H2O, H2S, and H2Se and LP/bond pair (LP/BP) repulsion in NH3, PH3, and AsH3. In parallel, changes in the H–M–H angles (M = O, S, Se, N, P, and As) are observed. The change in the H–M–H angle during the interactions was proportional to the amount of charge transferred from the bases to the cations and electron density (ρ) at the molecule/cation bond critical point. Also, the opposite trend for proton affinities of these two families, that is, NH3 > PH3 > AsH3 and H2O < H2S < H2Se, was interpreted on the basis of LP/BP repulsion in their neutral and protonated forms. Interaction of the Lewis bases with neutral Lewis acids including BeH2, BeF2, and BH3 was studied energetically and structurally. The calculated energies for interactions of H2O and NH3 with BeH2, BeF2, and BH3 are larger than the corresponding values for H2S, H2Se, PH3, and AsH3. This difference was interpreted on the basis of the lower stability of H2O and NH3 because of large LP/LP and LP/BP repulsion in H2O and LP/BP repulsion in NH3.

Reversal of Sp1 transactivation and TGFβ1/SMAD1 signaling by H2S prevent nickel-induced fibroblast activation

Nickel as a heavy metal is known to bring threat to human health, and nickel exposure is associated with changes in fibroblast activation which may contribute to its fibrotic properties. H2S has recently emerged as an important gasotransmitter involved in numerous cellular signal transduction and pathophysiological responses. Interaction of nickel and H2S on fibroblast cell activation has not been studied so far. Here, we showed that a lower dose of nickel (200 μM) induced the activation of human fibroblast cells, as evidenced by increased cell growth, migration and higher expressions of α-smooth muscle actin (αSMA) and fibronectin, while high dose of nickel (1 mM) inhibited cell viability. Nickel reduced intracellular thiol contents and stimulated oxidative stress. Nickel also repressed the mRNA and protein expression of cystathionine gamma-lyase (CSE, a H2S-generating gene) and blocked the endogenous production of H2S. Exogenously applied NaHS (a H2S donor) had no effect on nickel-induced cell viability but significantly attenuated nickel-stimulated cell migration and the expression of αSMA and fibronectin. In contrast, CSE deficiency worsened nickel-induced αSMA expression. Moreover, H2S incubation reversed nickel-stimulated TGFβ1/SMAD1 signal and blocked TGFβ1-initiated expressions of αSMA and fibronectin. Nickel inhibited the interaction of Sp1 with CSE promoter but strengthened the binding of Sp1 with TGFβ1 promoter, which was reversed by exogenously applied NaHS. These data reveal that H2S protects from nickel-stimulated fibroblast activation and CSE/H2S system can be a potential target for the treatment of tissue fibrosis induced by nickel.

Quantum-Chemical Analysis of the Mechanism of Degradation of Binary Platinum Nanoclusters with Sulfur-Containing Compounds

We propose a quantum-chemical model of poisoning of binary Pt42Me13 platinum nanoclusters (where Me is a transition metal, namely, Fe, Co, or Ni) with core-shell structure by hydrogen sulfide and sulfur dioxide in media of low-temperature fuel cells. This model is based on the evaluation of the adsorption characteristics of interaction of H2S and SO2 molecules with the surfaces of nanoclusters. It is shown that their susceptibility to the formation of strong chemisorption bonds with H2S and SO2 molecules depends on the type of nanocluster core and the sites of adsorption on their surfaces. By using the quantum-chemical method of density functional, we establish the regularities of influence of the cores of binary nanoclusters of transition metals Fe, Co, or Ni on the geometric and energy characteristics of the adsorption of molecules. We also propose the mechanism of interaction of H2S and SO2 molecules with binary platinum nanoclusters based on the changes in the electronic properties of the surface platinum atoms or in the distribution of active adsorption centers on the surface of nanoclusters depending on the type of the core. The accumulated results confirm the prospects of the density functional method in the theoretical evaluation of the influence of chemical composition and the structure of binary nanoparticles on their properties in the reactions of low-temperature fuel cells.

Fe(III) – Sulfide interaction in globins: Characterization and quest for a putative Fe(IV)-sulfide species

The present study reports findings regarding the contrast between H2S interaction with bovine hemoglobin (Hb) and horse heart myoglobin (Mb), in terms of binding and dissociation kinetics, affinities, and mechanism. At pH9.5, oxidation of ferric-sulfide adducts in presence of no free sulfide, using hexachloroiridate as oxidant is examined using stopped-flow UV–vis, EPR, vibrational spectroscopy and mass spectrometry. Oxidation of the ferric-sulfide adduct in such conditions occurs with a putative unstable Fe(IV)-sulfide adduct as intermediate that finally leads to a paramagnetic ferric species with distinct EPR features. As detected by MS spectrometry, this final species appears to be a truncated form of globin at a distinct Tyr. In case of Hb, only β-chain is truncated at Tyr144.

Fe-doped graphene nanosheet as an adsorption platform of harmful gas molecules (CO, CO2, SO2 and H2S), and the co-adsorption in O2 environments

The adsorption of pollutant gases (CO, CO2, SO2 and H2S) onto Fe-doped graphene nanosheets (FeG) is studied on the basis of density functional theory calculations at the PBE/Def2-SVP level of theory. The most stable adsorption configurations, binding characteristics, electronic properties and stability at room temperature of the FeG–Gas interactions is fully analyzed. The gas molecules are chemisorbed onto FeG with adsorption energies in the range of 0.54–1.8eV, with an enhanced adsorption strength compared to intrinsic graphene. The stability of the FeG-Gas interactions is dominated by Lewis-acid-base interactions, and its strength is sorted as SO2>CO>H2S>CO2. The adsorption stability is also retained at room temperature (300K). Due to the strong interaction of SO2, CO, and H2S, FeG could catalyze or activate these gas molecules, suggesting the possibility of FeG as a catalyst substrate. The electron acceptor/donor character of CO, CO2, SO2 and H2S molecules when adsorbed onto FeG causes charge transfer processes that are responsible for the change in conductance of FeG; thus, the response of the HOMO-LUMO gap of FeG under gas adsorption could be useful for sensing applications. Furthermore, the analysis of the co-adsorption in O2 environments shows that the CO2 interaction turns unstable onto FeG, while the sensing response towards H2S is suppressed. Finally, these results give new insights into the emerging applications of Fe-doped graphene in gas capture/filtration devices, solid-state gas sensors or as a catalyst substrate.

Surface interaction of H2S, SO2, and SO3 on fullerene-like gallium nitride (GaN) nanostructure semiconductor

Density functional theory (DFT) using MPW1PW91 and B3LYP hybrid functionals was utilized for quantum-based investigations of three major sulfur compounds (H2S, SO2, and SO3) adsorption onto fullerene-like Ga12N12 nanocluster. All chemicals showed high chemisorption with the order of SO3>SO2>>H2S. Results of charge analysis showed that during adsorption, transfer of charge is from H2S to nanocluster while reverse direction of charge transfer is found for SO2 and SO3 molecules. Partial dissociation is found for adsorbates especially for SO2 and SO3 molecules. Results of thermochemistry analysis show negative values for enthalpy and Gibbs free energy of adsorption, confirming exothermic spontaneous process. Analysis of frontier molecular orbital (FMO) showed important role of orbital hybridizing towards formation of new bonds upon adsorption. As a result, we introduce Ga12N12 nanocluster as a strong adsorbent for sulfur compounds.

Sensitivity of salivary hydrogen sulfide to psychological stress and its association with exhaled nitric oxide and affect

BackgroundHydrogen sulfide (H2S) is the third gasotransmitter recently discovered after nitric oxide (NO) and carbon monoxide. Both NO and H2S are involved in multiple physiological functions. Whereas NO has been shown to vary with psychological stress, the influence of stress on H2S and the relationship between H2S and NO are unknown. We therefore examined levels of salivary H2S and NO in response to a stressful final academic exam period. MethodsMeasurements of stress, negative affect, and fraction of exhaled NO (FENO), were obtained from students (N=16) and saliva was collected at three time points: low-stress period in the semester, early exam period, and late exam period. Saliva was immediately analyzed for H2S with the fluorescent probe Sulfidefluor-4. ResultsH2S increased significantly during the early exam period and FENO decreased gradually towards the late exam period. H2S, FENO, negative affect, and stress ratings were positively associated with each other: as stress level and negative affect increased, values of H2S increased; in addition, as FENO levels decreased, H2S also decreased. Asthma status did not modify these associations. ConclusionSustained academic stress increases H2S and these changes are correlated with NO and the experience of stress and negative affect. These findings motivate research with larger samples to further explore the interaction and function of H2S and FENO during psychological stress.

Ratiometric Visualization of NO/H2S Cross-Talk in Living Cells and Tissues Using a Nitroxyl-Responsive Two-Photon Fluorescence Probe.

It is of scientific significance to explore the intricate relationship between two crucial gasotransmitters nitric oxide (NO) and hydrogen sulfide (H2S) because they exert similar and interdependent biological actions within the living organisms. Nevertheless, visualization of the NO/H2S crosstalk using effective molecular imaging tools remains challenging. To address this issue, and given that nitroxyl (HNO) has been implicated as the interdependent production of NO and H2S via a network of cascading chemical reactions, we herein design a ratiometric two-photon fluorescent probe for HNO, termed TP-Rho-HNO, which consists of benzo[h]chromene-rhodol scaffold as two-photon energy transfer cassette with phosphine moiety as specific HNO recognition unit. The newly proposed probe has been successfully applied in ratiometric two-photon bioimaging of endogenous HNO derived from NO and H2S interaction in the human umbilical vein cells (HUVECs) and as well as in rat brain tissues. Intriguingly, the imaging results consistently demonstrate that the mutually dependent upgeneration of H2S and NO are present in living biosystems, indicating that this molecular probe would provide a powerful approach to elucidate the chemical foundation for the anfractuous cross-talk between the NO and H2S signaling pathways in biology.

Polysulfides (H2Sn) produced from the interaction of hydrogen sulfide (H2S) and nitric oxide (NO) activate TRPA1 channels

Hydrogen sulfide (H2S) exerts synergistic effects with another gaseous signaling molecule nitric oxide (NO) on ion channels and vasculature. However, the mechanism of the synergy is not well understood. Here, we show that the interaction between H2S and NO generates polysulfides (H2Sn), which activate transient receptor potential ankyrin 1 (TRPA1) channels. High performance liquid chromatography with tandem mass spectrometry analysis, along with the imaging of intracellular Ca2+ and H2Sn, showed that H2Sn and their effects were abolished by cyanolysis and by reducing substances such as dithiothreitol (DTT), cysteine, and glutathione (GSH). However, the effects of nitroxyl or nitrosopersulfide, other potential products of H2S and NO interaction, are not affected by cyanolysis or reducing substances. This study demonstrates that H2Sn are products of synergy between H2S and NO and provides a new insight into the signaling mechanisms.

Highly enhanced H2S gas sensing and magnetic performances of metal doped hexagonal ZnO monolayer

Understanding the interaction mechanisms of hydrogen sulfite (H2S) with hexagonal ZnO monolayer (h-ZnO) is important in exploiting h-ZnO-based sensing devices. In this study, the effects of transitional metals on interaction of H2S with various h-ZnO have been investigated by density functional theory calculations. It was found that the electronic properties of h-ZnO/H2S systems can be effectively tuned by manipulating the configurations of H2S molecule on plane surface of the h-ZnO. Transitional metals (Pd, Au, Fe, and Co) doped h-ZnO exhibit much higher adsorption capacity to H2S compared with their undoped counterparts. The electronic and magnetic behaviors of the h-ZnO can be effectively modulated by the metal dopants and H2S adsorption. H2S adsorption does not change the magnetic properties of the nonmagnetic (NM) semiconductors, like Pd-h-ZnO and Au-h-ZnO, as well as the ferromagnetic half metal (FM-HM) of Co-h-ZnO. In contrast, the ferromagnetic metal (FM-metal) Fe-h-ZnO is converted to FM-HM after H2S adsorption. The results of this research indicate that transition metal doped h-ZnO nanosheets could be utilized as building blocks to design H2S sensors and magnetic devices.

Copper(II)-Mediated Hydrogen Sulfide and Thiol Oxidation to Disulfides and Organic Polysulfanes and Their Reductive Cleavage in Wine: Mechanistic Elucidation and Potential Applications.

Fermentation-derived volatile sulfur compounds (VSCs) are undesirable in wine and are often remediated in a process known as copper fining. In the present study, the addition of Cu(II) to model and real wine systems containing hydrogen sulfide (H2S) and thiols provided evidence for the generation of disulfides (disulfanes) and organic polysulfanes. Cu(II) fining of a white wine spiked with glutathione, H2S, and methanethiol (MeSH) resulted in the generation of MeSH-glutathione disulfide and trisulfane. In the present study, the mechanisms underlying the interaction of H2S and thiols with Cu(II) is discussed, and a prospective diagnostic test for releasing volatile sulfur compounds from their nonvolatile forms in wine is investigated. This test utilized a combination of reducing agents, metal chelators, and low-oxygen conditions to promote the release of H2S and MeSH, at levels above their reported sensory thresholds, from red and white wines that were otherwise free of sulfidic off-odors at the time of addition.

A Monte Carlo simulation study to predict the solubility of H2S in ionic liquids with 1-butyl-3-methylimidazolium ([C4mim+]) cation and tetrafluoroborate ([BF4−]), hexaflorophosphate ([PF6−]) and bis(trifluoromethanesulfonyl)amide ([Tf2N−]) anions

The solubilities of H2S in ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim+][BF4−]), 1-butyl-3-methylimidazolium hexaflorophosphate ([C4mim+][PF6−]) and -butyl-3-methylimidazolium tetrafluoroborate bis(trifluoromethanesulphonyl)amide ([C4mim+][Tf2N−]) are predicted using isothermal–isobaric Gibbs ensemble Monte Carlo method (NPT-GEMC) at temperatures ranging from 333 to 453 K and pressure up to 20 bar. The low pressure points (up to 3 bar) of the absorption isotherms are fitted to a straight line to get a rough estimation of the Henry’s law constants. The van’t Hoff relationship is used to estimate the partial molar enthalpy of the absorption. The obtained results are in a good agreement with Jou and Mather [18], and Jalili et al. [13]. When comparing the solubility in ILs, it is found that H2S solubility is highest for [C4mim+][Tf2N−], followed by [C4mim+][PF6−]. The lowest solubility is observed in [C4mim+][BF4−]. The highest solubility in [C4mim+][Tf2N−] is consistent with Jalili et al. [13]. However, their results indicate slightly higher solubility in [C4mim+][BF4−] than in [C4mim+][PF6−], and do not agree with the predictions. Upon absorption, the molar volumes of the mixtures decrease linearly, showing only small changes in volume. The effect of H2S absorption on ILs is further studied by calculating the radial distribution functions between the ions. The results indicate that the solute molecules accommodate themselves in the cavities without significantly disturbing the ionic arrangement of the ions, similar to CO2 absorption in ILs. The spatial distribution functions show similar spatial distribution for H2S around cation in all of the studied ILs, whereas the distribution around anion depends on the shape and flexibility of the anion. The mechanism of H2S absorption is studied by computing the van der Waals (VDW) and electrostatic (ELEC) energies. It is observed that the solubility of H2S in the studied ILs is primarily controlled by VDW interaction. When comparing the interaction of H2S with the ions, it is found that solute molecules interact with cations mainly due to VDW interaction. Both VDW and ELEC energies contribute in the interaction between H2S and anions.

Hydrogen Sulfide as a "Double-Faced" Compound: One with Pro- and Antioxidant Effect.

Hydrogen sulfide (H2S), like other gasotransmitters such as nitric oxide (NO•) and carbon monoxide (CO), acts as a signaling molecule in various biological systems. It may also regulate the oxidative stress observed in several diseases sometimes associated with changes of H2S concentration. This chapter describes the "double face" of hydrogen sulfide as both an antioxidant and a prooxidant in biological systems. One proposed mechanism by which H2S exerts its antioxidative effects is its ability to modulate the concentration of glutathione, which is a very important physiological antioxidant. This chapter discusses the interactions of H2S with various reactive oxygen species and reactive nitrogen species, including the superoxide radical anion [Formula: see text] , hydrogen peroxide (H2O2), and peroxynitrite anion (ONOO-), which is produced in a rapid reaction between [Formula: see text] and NO•.

The interaction of estrogen and CSE/H2S pathway in the development of atherosclerosis.

Both estrogen and hydrogen sulfide (H2S) have been shown to inhibit the development of atherosclerosis. We previously reported that cystathionine γ-lyase knockout (CSE-KO) male mice develop atherosclerosis earlier than male wild-type (WT) mice. The present study investigated the interaction of CSE/H2S pathway and estrogen on the development of atherosclerosis in female mice. Plasma estrogen levels were significantly lower in female CSE-KO mice than in female WT mice. NaHS treatment had no effect on plasma estrogen levels in both WT and CSE-KO female mice. After CSE-KO and WT female mice were fed with atherogenic diet for 12 wk, plasma lipid levels were significantly increased and triglyceride levels decreased compared with those of control diet-fed mice. Atherogenic diet induced more atherosclerotic lesion, oxidative stress, intracellular adhesion molecule-1 (ICAM-1), and NF-κB in CSE-KO mice than in WT mice. Estrogen treatment of atherogenic diet-fed WT mice attenuated hypercholesterolemia, oxidative stress, ICAM-1 expression, and NF-κB in WT mice but not in atherogenic diet-fed CSE-KO mice. Furthermore, H2S production in both the liver and vascular tissues was enhanced by estrogen in WT mice but not in CSE-KO mice. It is concluded that the antiatherosclerotic effect of estrogen is mediated by CSE-generated H2S. This study provides new insights into the interaction of H2S and estrogen signaling pathways on the regulation of cardiovascular functions.NEW & NOTEWORTHY Female cystathionine γ-lyase (CSE)-knockout mice have significantly lower plasma estrogen levels and more severe early atherosclerotic lesion than female wild-type mice. H2S production in liver and vascular tissues is enhanced by estrogen via its stimulatory effect on CSE activity. The antiatherosclerotic effect of estrogen is mediated by CSE-generated H2S.

Comparative Theoretical Study of the Chemistry of Hydrogen Sulfide on Cu(100) and Au(100): Implications for Sulfur Tolerance of Water Gas Shift Nanocatalysts

(100)-like planes have been thought to play a pivotal role in catalyzing the water gas shift (WGS) reaction on complicated face-centered cubic metal nanoclusters, such as Cu29 and Au29 supported over ZnO. Understanding their sulfur poisoning effect is highly desirable yet very challenging. Accordingly, as an important first step toward addressing this interesting issue, we applied a combination of periodic, self-consistent density functional theory (DFT-GGA) calculations and microkinetics to investigate the interaction of H2S with the extended model surfaces Cu(100) and Au(100) under realistic conditions. Through our calculations, a scaling relationship of the adsorption enthalpy for HxS (x = 0–2) on each surface was put forward. On the former substrate, the scission of the H–S bonds was found to be more facile in energy than that on the latter one; however, the recombinative desorption of the dissociated H atoms is less favored. The barrier of the rate-determining step of H2S decomposing to S at the Cu f...