Regulation of cardiovascular cell function by hydrogen sulfide (H2S)

Since the discovery of endogenously‐produced hydrogen sulfide (H₂S) in various tissues, there has been an explosion of interest in H₂S as a biological mediator alongside other gaseous mediators, nitric oxide and carbon monoxide. The identification of enzyme‐regulated H₂S synthetic pathways in the cardiovascular system has led to a number of studies examining specific regulatory actions of H₂S. We review evidence showing that endogenously‐generated and exogenously‐administered H₂S exerts a wide range of actions in vascular and myocardial cells including vasodilator/vasoconstrictor effects via modification of the smooth muscle tone, induction of apoptosis and anti‐proliferative responses in the smooth muscle cells, angiogenic actions, effects relevant to inflammation and shock, and cytoprotection in models of myocardial ischemia‐reperfusion injury. Several molecular mechanisms of action of H₂S have been described. These include interactions of H₂S with NO, redox regulation of multiple signaling proteins and regulation of K_ATP channel opening. The gaps in our current understanding of precise mechanisms, the absence of selective pharmacological tools and the limited availability of H₂S measurement techniques for living tissues, leave many questions about physiological and pathophysiological roles of H₂S unanswered at present. Nevertheless, this area of investigation is advancing rapidly. We believe H₂S holds promise as an endogenous mediator controlling a wide range of cardiovascular cell functions and integrated responses under both physiological and pathological conditions and may be amenable to therapeutic manipulation. Copyright © 2010 John Wiley & Sons, Ltd.     

不同时期喷施NaHS对盐碱胁迫下裸燕麦H2S产生和活性氧代谢的影响

为了解气体信号硫化氢（H₂S）对盐碱胁迫下裸燕麦（Avena nuda）活性氧（ROS）代谢的调节效应,筛选和确定H₂S最佳的施用时期和适宜浓度。采用盆栽土培试验,研究了在裸燕麦不同时期（幼苗期、拔节期、抽穗期、开花期和灌浆期）喷施0、25、50、100、200、400 μmol·L^-1 H₂S供体硫氢化钠（NaHS）对3.0 g·kg^-1盐碱混合 （NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃摩尔比为12∶8∶9∶1）胁迫下裸燕麦叶片H₂S含量、H₂S生成关键酶L-半胱氨酸脱巯基酶（LCD）活性和ROS代谢相关物质含量和酶活性的影响。结果表明：喷施时期和NaHS浓度及其交互作用对盐碱胁迫下裸燕麦叶片中H₂S、超氧阴离子（）、过氧化氢（H₂O₂）、丙二醛（MDA）、抗坏血酸（AsA）和谷胱甘肽（GSH）含量及LCD、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性存在显著影响。与喷施0 μmol?L^-1 NaHS相比,喷施一定浓度NaHS能够提高H₂S、AsA、GSH含量和LCD、SOD、CAT、POD、APX和GR活性,减少、H₂O₂和MDA积累,但以上各指标最佳的喷施时期和NaHS浓度存在差异。隶属函数综合分析显示,在幼苗期和拔节期喷施25~200 μmol?L^-1 NaHS的综合评价值（D）最高,表明在幼苗—拔节期喷施25~200 μmol?L^-1 NaHS能更好提高ROS清除能力,从而缓解盐碱胁迫诱导ROS对裸燕麦的氧化伤害。     

Highly efficient and rapid generation of human pluripotent stem cells by chemical reprogramming

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外源性H2S对糖尿病小鼠肝纤维化的作用及其机制*

目的: 探讨外源性硫化氢(H₂S)对糖尿病小鼠肝纤维化作用及其相关机制。方法: 将 C57 雄性体重为(22±2)g 24只小鼠随机分为3组(n=8):①正常对照组(Control):小鼠腹腔注射生理盐水,注射时间同实验组;②糖尿病模型组(HG):按体重(150 mg/kg)一次性腹腔注射链脲佐菌素(STZ)诱导小鼠建立糖尿病模型;③NaHS 处理组(HG + NaHS):方法同组别②,只是糖尿病模型建立后,腹腔注射NaHS(100 μmol/L·kg·d),每天一次,连续12周。HE染色检测肝细胞损伤;Masson染色检测肝纤维化;Western blot检测相关蛋白胱硫醚-β-合成酶(CBS,内源性H₂S产生的关键酶)、胶原I (Col-I)、胶原III (Col-III)和基质金属蛋白酶-9(MMP-9)的表达。结果: 与对照组比较,糖尿病模型组肝细胞损伤及肝纤维化均显著加重,CBS 蛋白表达显著减少(P＜0.01),Col-I、Col-III和MMP-9蛋白表达均显著增加(P＜0.01)。与糖尿病模型组比较,NaHS处理组肝细胞损伤及肝纤维化均显著减轻、CBS 蛋白表达显著增加、Col-I、Col-III和MMP-9蛋白表达均减少(P＜0.01)。结论: 外源性H₂S可抑制糖尿病小鼠肝纤维化,其机制与降低胶原含量和基质金属蛋白酶-9的表达相关。     

H2S对干旱胁迫下高山离子芥的作用研究

以高山冰缘植物高山离子芥（Chorispora bungeana）试管苗为实验材料,研究了0.3 mol·L^-1甘露醇模拟干旱胁迫响应过程中硫化氢（H₂S）调节高山离子芥的膜系统损伤程度、渗透调节物质和抗氧化酶系的作用,以及磷脂酶D（PLD）、活性氧（ROS）与H₂S信号分子在高山离子芥中响应干旱胁迫中的作用和可能存在的信号关系。结果显示：干旱胁迫下,外施H₂S供体NaHS显著降低高山离子芥电解质渗漏率及MDA含量、抑制ROS产生,提高渗透调节物质和抗氧化水平,从而增强高山离子芥的抗旱能力;干旱可诱导PLD活性、H₂S含量、ROS发生显著变化;当分别外施PLD下游产物PA与ROS供体H₂O₂均可促进干旱胁迫下H₂S的释放,当同时外施PA和ROS抑制剂DPI时对干旱胁迫下H₂S含量没有显著影响,当同时外施PLD抑制剂正丁醇与ROS抑制剂DPI则显著抑制干旱胁迫下H₂S含量的产生,表明干旱胁迫下,高山离子芥中ROS位于PLD的下游、H₂S的上游发挥作用。     

干旱胁迫下拟南芥中H_2S与ABA信号关系研究

以野生型拟南芥(WT)、硫化氢(H_2S)合成酶缺失型突变体lcd、脱落酸(ABA)合成缺失型突变体aba1实生苗为材料,以0.3 mol·L^-1甘露醇模拟干旱胁迫,研究干旱胁迫对ABA含量、H_2S含量的影响,及其在拟南芥抵抗干旱胁迫中的作用及信号关系。结果显示:干旱胁迫显著提高LCD和ABA1基因相对表达以及H_2S含量,ABA含量;干旱胁迫显著抑制突变体lcd、aba1的种子萌发;干旱胁迫下,外施NaHS促进干旱胁迫下WT、lcd和aba1中內源H_2S的产生及上调LCD、ABA1基因相对表达,而外施ABA提高干旱胁迫下WT、aba1中H_2S含量及LCD、ABA1基因相对表达,但是对lcd中H_2S含量及LCD基因相对表达没有显著影响。研究结果表明,信号分子H_2S和ABA在拟南芥的干旱胁迫响应中发挥一定的作用,且H_2S位于ABA的下游参与调控拟南芥的信号过程。     

Involvement of oxidative stress in the regulation of H(2)S production during ultradian metabolic oscillation of Saccharomyces cerevisiae

Periodic evolution of H(2)S during aerobic chemostat culture of Saccharomyces cerevisiae resulted in ultradian metabolic oscillation via periodic inhibition of respiratory activity. To understand the nature of periodic H(2)S evolution, we investigated whether oxidative stress is associated with H(2)S production. The cellular oxidative states represented by intracellular level of lipid peroxides oscillated out of phase with the oscillation of dissolved O(2). Pulse addition of antioxidant, oxidative agent or inhibitor of antioxidation enzymes perturbed metabolic oscillation producing changes in H(2)S evolution. Analysis of H(2)S production profiles during perturbation of oscillation revealed that the amount of H(2)S production is closely linked with cellular oxidative states. Based on these results and our previous reports, we suggest that oxidative stresses result in periodic depletion of glutathione and cysteine, which in turn causes stimulation of the sulfate assimilation pathway and H(2)S production.     

The timing of diammonium phosphate supplementation of wine must affects subsequent H2S release during fermentation

Aims:  The aim of this study was to evaluate the impact of supplementation by diammonium phosphate (DAP) on hydrogen sulfide (H₂S) production, when DAP given either prior to fermentation or during the early stationary growth phase of yeast. Methods and Results:  Three contrasting Saccharomyces cerevisiae wine strains were used to ferment synthetic grape juice (GJ) containing 67 mg l^?1 of initial yeast assimilable nitrogen (YAN), supplied either as DAP or as mixture of amino acids. Sufficient DAP was added either prior to or 72 h after the initiation of fermentation to achieve a final YAN concentration of 267 mg l^?1. Supplementation prior to fermentation stimulated H₂S production. The results obtained in model solutions were validated using natural GJ. Conclusion:  The timing of DAP supplementation is critical for ensuring that fermentation proceeds without excessive release of H₂S. Significance and Impact of the Study:  This result has important implications for the wine‐making industry, because it highlights the value of determining the initial nitrogen level of a GJ. It raises awareness of the dependence of wine quality on the correct timing of DAP supplementation.     

The role and molecular mechanism of metabolic reprogramming of colorectal cancer by UBR5 through PYK2 regulation of OXPHOS expression study

Colorectal carcinoma (CRC) is the third most malignant tumor in the world, but the key mechanisms of CRC progression have not been confirmed. UBR5 and PYK2 expression levels were detected by RT-qPCR. The levels of UBR5, PYK2, and mitochondrial oxidative phosphorylation (OXPHOS) complexes were detected by western blot analysis. Flow cytometry was used to detect ROS activity. The CCK-8 assay was used to assess cell proliferation and viability. The interaction between UBR5 and PYK2 was detected by immunoprecipitation. A clone formation assay was used to determine the cell clone formation rate. The ATP level and lactate production of each group of cells were detected by the kit. EdU staining was performed for cell proliferation.Transwell assay was performed for cell migration ability. For the CRC nude mouse model, we also observed and recorded the volume and mass of tumor-forming tumors. The expression of UBR5 and PYK2 was elevated in both CRC and human colonic mucosal epithelial cell lines, and knockdown of UBR5 had inhibitory effects on cancer cell proliferation and cloning and other behaviors in the CRC process by knockdown of UBR5 to downregulate the expression of PYK2, thus inhibiting the OXPHOS process in CRC; rotenone (OXPHOS inhibitor) treatment enhanced all these inhibitory effects. Knockdown of UBR5 can reduce the expression level of PYK2, thus downregulating the OXPHOS process in CRC cell lines and inhibiting the CRC metabolic reprogramming process.     

内源性硫化氢在中枢神经系统中的作用研究进展

硫化氢是继NO和CO之后发现的又一种新的气体信号分子,其被认为是一种神经递质,在中枢神经系统中起着重要的作用。内源性H2S主要由胱硫醚-β合酶(CBS)和胱硫醚γ-裂解酶(CSE)合成,其不仅可以直接作用于中枢神经系统发挥作用,还能通过抗氧化、调节神经内分泌及脑血管功能,进而间接影响中枢神经系统功能,具有广泛的生理作用。近年来,越来越多的研究发现内源性H2S在AD、热惊厥、PD、脑卒中、缺血再灌注脑损伤及遗传性疾病脑损害等神经系统疾病的发病过程中也起着重要作用。本文简要介绍H2S的生化和生理特点,并总结其在中枢神经系统中作用的进展。     

l‐cysteine desulfhydrase‐related H2S production is involved in OsSE5‐promoted ammonium tolerance in roots of Oryza sativa

Previous studies revealed that rice heme oxygenase PHOTOPERIOD SENSITIVITY 5 (OsSE5) is involved in the regulation of tolerance to excess ammonium by enhancing antioxidant defence. In this study, the relationship between OsSE5 and hydrogen sulfide (H₂S), a well‐known signalling molecule, was investigated. Results showed that NH₄Cl triggered the induction of l ‐cysteine desulfhydrase (l ‐DES)‐related H₂S production in rice seedling roots. A H₂S donor not only alleviated the excess ammonium‐triggered inhibition of root growth but also reduced endogenous ammonium, both of which were aggravated by hypotaurine (HT, a H₂S scavenger) or dl ‐propargylglycine (PAG, a l ‐DES inhibitor). Nitrogen metabolism‐related enzymes were activated by H₂S, thus resulting in the induction of amino acid synthesis and total nitrogen content. Interestingly, the activity of l ‐DES, as well as the enzymes involved in nitrogen metabolism, was significantly increased in the OsSE5‐overexpression line (35S:OsSE5), whereas it impaired in the OsSE5‐knockdown mutant (OsSE5‐RNAi). The application of the HT/PAG or H₂S donor could differentially block or rescue NH₄Cl‐hyposensitivity or hypersensitivity phenotypes in 35S:OsSE5‐1 or OsSE5‐RNAi‐1 plants, with a concomitant modulation of nitrogen assimilation. Taken together, these results illustrated that H₂S function as an indispensable positive regulator participated in OsSE5‐promoted ammonium tolerance, in which nitrogen metabolism was facilitated.     

外源性H2S恢复缺氧后适应对衰老H9C2细胞的保护作用及机制

目的：探讨外源性硫化氢（H₂S）恢复缺氧后适应对衰老H9C2细胞的保护作用及相关机制。方法：H9C2细胞（心肌细胞系）用30 μmol/L过氧化氢（H₂O₂）处理2 h后再培养3 d,诱导生成衰老细胞。衰老H9C2细胞被随机分5组（n=8）：正常组（Control）、缺氧/复氧组（H/R）、H/R+NaHS组、缺氧后适应（PC）组、PC+NaHS组。缺氧/复氧（H/R）模型：衰老H9C2细胞用缺氧液（无血清、无糖培养基,pH=6.8）培养3 h,然后正常培养6 h;缺氧后适应（PC）模型：方法同H/R模型,缺氧结束复氧前连续进行3次5 min间隔的复氧/再缺氧处理,随后复氧6 h。ELISA试剂盒分别检测大鼠晚期糖基化终末产物（AGEs）含量和caspase-3活性;CCK-8试剂盒检测细胞活力;DCFH-DA染色检测活性氧（ROS）水平;Hoechst 33342染色检测细胞凋亡率;Real-time PCR检测相关基因mRNA水平。结果：30 μmol/L H₂O₂可诱导H9C2细胞衰老但不会导致其凋亡;与Control组比较,H/R和PC均降低细胞活力,增加细胞凋亡率、ROS水平及caspase-3、caspase-9和Bcl-2 mRNA水平（P<0.01）;且PC组与H/R组比较,上述指标变化无明显差异;在H/R和PC组加入NaHS,可显著提高细胞活力,降低细胞凋亡率和氧化应激;PC+NaHS对上述指标的作用明显强于H/R+NaHS。结论：外源性H₂S能够恢复PC对衰老H9C2细胞的保护作用,其机制与抑制氧化应激和细胞凋亡有关。     

硫化氢对大鼠心肌缺血/再灌注损伤的保护作用及其对c-Fos蛋白表达的影响

为探讨硫化氢(hydrogen sulfide,H2S)对大鼠心肌缺血,再灌注(ischemia/reperfusion,I/R)损伤的保护作用及机制,雄性Sprague-Dawley大鼠被随机分为对照组(假手术组)、I/R组、2.8μmol/kg体重NaHS干预组、14 μmol/kg体重NaHS干预组.结扎冠状动脉前降支30 min后,松扎再灌注60 min,心电图Ⅱ导联检测和TTC染色测定心肌梗死面积评价制作的心肌I/R模型:测定血浆中H2S浓度变化;监测血流动力学指标(LVSP,LV±dp/dtmax);HE染色和透射电镜观察心肌形态学改变;免疫组织化学方法测定心肌组织中c-Fos蛋白表达.结果显示:心肌I/R后血浆中H2S浓度明显低于对照组[(30.32±5.26)vs(58.28±7.86)μmol/L,P<0.05]:2.8和14μmol/kg体重NaHS均可显著改善I/R引起的心功能改变,且14μmol/kg体重NaHS较2.8 μmol/kg体重NaHS作用强;14 μmol/kg体重NaHS明显减轻心肌形态学及超微结构损伤,同时降低大鼠I/R心肌组织中c-Fos蛋白表达(0.20±0.06vs0.32±0.10,P<0.05).以上结果提示,H2S对大鼠心肌的I/R损伤有保护作用,这可能与其降低c-Fos蛋白表达有关.     

IDH2 stabilizes HIF‐1α‐induced metabolic reprogramming and promotes chemoresistance in urothelial cancer

Drug resistance contributes to poor therapeutic response in urothelial carcinoma (UC). Metabolomic analysis suggested metabolic reprogramming in gemcitabine‐resistant urothelial carcinoma cells, whereby increased aerobic glycolysis and metabolic stimulation of the pentose phosphate pathway (PPP) promoted pyrimidine biosynthesis to increase the production of the gemcitabine competitor deoxycytidine triphosphate (dCTP) that diminishes its therapeutic effect. Furthermore, we observed that gain‐of‐function of isocitrate dehydrogenase 2 (IDH2) induced reductive glutamine metabolism to stabilize Hif‐1α expression and consequently stimulate aerobic glycolysis and PPP bypass in gemcitabine‐resistant UC cells. Interestingly, IDH2‐mediated metabolic reprogramming also caused cross resistance to CDDP, by elevating the antioxidant defense via increased NADPH and glutathione production. Downregulation or pharmacological suppression of IDH2 restored chemosensitivity. Since the expression of key metabolic enzymes, such as TIGAR, TKT, and CTPS1, were affected by IDH2‐mediated metabolic reprogramming and related to poor prognosis in patients, IDH2 might become a new therapeutic target for restoring chemosensitivity in chemo‐resistant urothelial carcinoma.     

Effect of long-term H2S fumigation on photosynthesis in spinach. Correlation between CO2 fixation and chlorophyll a fluorescence

Spinach plunts (Spinacia oleracea L. cv. Monosa) were exposed to air with and without 0.25 μl l^-1 H₂S. Effects of H₂S exposure for up to 18 days on photosynthesis, dark respiration and on chlorophyll a fluorescence were studied. Dark respiration was not affected by H₂S fumigation. Photosynthetic CO₂ fixation decreased linearly with time in both control and fumigated plants. The rate of decrease in CO₂ fixation was faster in the fumigated plants; after 14 days of exposure the fumigated plants showed a decrease in CO₂ fixation of 23%äs compared with the control plants. The H₂S-induced decrease in CO₂ fixation was accompanied by a decrease in quenching of the chlorophyll fluorescence. The most characteristic change in chlorophyll fluorescence was a decreased difference between maximum and steady-state fluorescence [(P-T)/P), suggesting a reduced efficiency in the use of photochemical energy in photosynthesis. Differences in CO₂ fixation were more pronounced whcn measured at high light intensity; the maximum rate of CO₂ fixation at light saturation decreased significantly with time in the H₂S-exposed plants; after 14 days of H₂S exposure a decrease of more than 70% was noted. The decrease in CO₂ fixation could not be attributed to a decreased chlorophyll content; on the contrary, chlorophyll content even slightly increased during fumigation. The initial increase in CO₂ fixation rate with increasing light intensity was also reduced by prolonged H₂S fumigation, indicating an effect of H₂S fumigation on photosynthetic electron transport. Finally, the phytotoxicity of H₂S is discusscd in relation to the H₂S-induced changes in photosynthetic CO₂ fixation and chlorophyll a fluorescence, and the effect of H₂S on leaf development observed in earlier studies.     

外源硫化氢对豌豆根尖及其边缘细胞的影响

为研究外源硫化氢（H2S）对豌豆（Pisum sativum）胚根生理特性及其边缘细胞的影响,测定了不同浓度外源H2S处理下豌豆根长、根尖组织可溶性蛋白质含量、抗氧化酶（APX、CAT、POD和SOD）活性、根尖边缘细胞存活率及其粘胶层相对面积的变化。结果表明：低浓度（0-40μmol·L-1）H2S可促进豌豆胚根生长,根尖组织可溶性蛋白质含量升高,SOD、APX和POD活性增加,CAT活性降低,根尖边缘细胞存活率上升,粘胶层相对面积变小。高浓度（60-80μmol·L-1）H2S可抑制豌豆胚根生长,可溶性蛋白质含量和边缘细胞存活率明显下降,APX和POD活性降低,CAT活性升高,SOD活性没有明显变化,粘胶层相对面积变大;边缘细胞染色体凝集并边缘化,然后逐渐降解并伴随粉末化,细胞质膜皱缩。因此,推测H2S可能在植物体内发挥着重要的生理作用。