Hydrogen Sulfide Donor Research Articles

Participation of Hydrogen Sulfide in Induction of Antioxidant System in Roots of Wheat Plantlets and Their Heat Resistance by Salicylic Acid

The possible role of hydrogen sulfide as a signal mediator in the induction of heat resistance of wheat (Triticum aestivum L.) plantlets by salicylic acid (SA) has been studied. The treatment of plantlets with SA (1 and 10 μM) or a hydrogen sulfide donor (NaHS, 0.1 and 0.25 mM) increased their resistance to damaging heating (10 min at 45°C). Under the influence of SA, a transient increase in the hydrogen sulfide content occurred in roots with the maximum effect in 2–3 h after the start of treatment. The treatment of roots with SA increased the activity of superoxide dismutase (SOD), catalase, and guaiacol peroxidase in them. Under the influence of the hydrogen sulfide donor NaHS, the activity of SOD and catalase increased significantly. Also, the treatment of roots with SA and NaHS reduced the effect of the accumulation of the product of lipid peroxidation, malondialdehyde, which is caused by heating. The inhibitors of hydrogen sulfide synthesis, hydroxylamine and potassium pyruvate, partially eliminated the effects of the increase in the activity of antioxidant enzymes and the development of heat resistance caused by SA. At the same time, the combined treatment of intact plantlets with 10 μM SA and 0.1 mM NaHS contributed to the additional increase in the activity of antioxidant enzymes and increased plantlet survival after heating. It is concluded that hydrogen sulfide participates in the implementation of the protective influence of SA on wheat plantlets under heat stress.

Design, synthesis and biological evaluation of 4-aniline quinazoline derivatives conjugated with hydrogen sulfide (H2S) donors as potent EGFR inhibitors against L858R resistance mutation

In this study, a series of 4-aniline quinazoline derivatives bearing hydrogen sulfide (H2S) donors were designed, synthesized and evaluated for biological activities. The synthesized compounds were screened for the enzymatic activities against EGFR and EGFR mutants by kinase target-based cell screening method. The results demonstrate that most compounds exhibit selectively inhibitory activities against TEL-EGFR-L858R–BaF3, especially compound 9h with GI50 = 0.008 μM (TEL-EGFR-L858R–BaF3), 0.0069 μM (TEL-EGFR-C797S–BaF3), >10 μM (BaF3), >10 μM (TEL-EGFR-BaF3) and 6.03 μM (TEL-EGFR-T790M-L858R–BaF3). The results from anti-proliferative assays in two NSCLC cell lines indicate that synthetic derivatives (9g, 9h, 15e and 15f) with H2S donor ACS81 display greater anti-proliferative potency against NSCLC cell line H3255 bearing EGFR mutant (L858R) with GI50 values ranging from 0.3486 to 1.348 μM. In addition, compound 9h exhibits weak anti-proliferative effects on other tumor cells (HepG2, MCF-7, HT-29 and A431) and has lower toxic effect on HUVEC cells than AZD9291 (positive control). Meanwhile, compound 9h inhibits the phosphorylation of EGFR in H3255 cells in a dose-dependent manner. Cell cycle analysis reveals that compound 9h suppresses the proliferation of cells by inducing cell cycle arrest in G0-G1 phase. The result of H2S release evaluation suggests that the H2S release of compound 9h is significantly more and faster than other compounds.

Searching for novel hydrogen sulfide donors: The vascular effects of two thiourea derivatives

The gasotransmitter hydrogen sulfide (H2S) is involved in the regulation of the vascular tone and an impairment of its endogenous production may play a role in hypertension. Thus, the administration of exogenous H2S may be a possible novel and effective strategy to control blood pressure. Some natural and synthetic sulfur compounds are suitable H2S-donors, exhibiting long-lasting H2S release; however, novel H2S-releasing agents are needed to improve the pharmacological armamentarium for the treatment of cardiovascular diseases.For this purpose, N-phenylthiourea (PTU) and N,N’-diphenylthiourea (DPTU) compounds have been investigated as potential H2S-donors. The thioureas showed long-lasting H2S donation in cell free environment and in human aortic smooth muscle cells (HASMCs). In HASMCs, DPTU caused membrane hyperpolarization, mediated by activation of KATP and Kv7 potassium channels. The thiourea derivatives promoted vasodilation in rat aortic rings, which was abolished by KATP and Kv7 blockers. The vasorelaxing effects were also observed in angiotensin II-constricted coronary vessels.In conclusion, thiourea represents an original H2S-donor functional group, which releases H2S with slow and long lasting kinetic, and promotes typical H2S-mediated vascular effects. Such a moiety will be extremely useful for developing original cardiovascular drugs and new chemical tools for investigating the pharmacological roles of H2S.

CHANGES IN THE STRUCTURAL CHARACTERISTICS OF PLATELETS AND LEUKOCYTES IN PATIENTS WITH ARTERIAL HYPERTENSION UNDER THE INFLUENCE OF A HYDROGEN SULFIDE DONOR

The aim of the research. The influence of hydrogen sulphide donor on some structural characteristics of platelets and leukocytes in patients with arterial hypertension was studied. Materials and methods. The survey involved patients (men) with hypertension aged 30–60 years, who were divided into 2 age groups: 30–40 years and 40–60 years. Control groups (healthy men without signs of hypertension) were randomized by age. Electron microscopic and morphometric research methods were used in the investigation. Results. Electron microscopic and morphometric evaluation of the structure of these cells has shown that it undergoes significant changes depending on patient’s age. In the persons of the older age group, the cells contained a reduced number of dense δ-granules and increased – α-granules, which may indicate an impaired serotonin balance and increased susceptibility to thrombogenesis. The younger age group presented structural changes in platelets in a reversed order. Adding hydrogen sulphide donor at a dose of 400 mg per day (phytopreparation Full Spectrum Garlic – Swanson Health Products, USA) to the traditional therapy of arterial hypertension leads to positive changes in the ultrastructure of the studied cells aimed at restoring the balance of serotonin, reducing the tendency to thrombogenesis, increasing the energy capacity of the mitochondrial apparatus. Conclusion. The obtained results indicate that detected effects significantly depend on the patient’s age (younger people respond more intensively) and the duration of the use of hydrogen sulphide donor (longer use is accompanied by more pronounced positive changes).

The Effect of a Fast-Releasing Hydrogen Sulfide Donor on Vascularization of Subcutaneous Scaffolds in Immunocompetent and Immunocompromised Mice.

Islet transplantation into subcutaneous polymer scaffolds has shown to successfully induce normoglycemia in type 1 diabetes models. Vascularization of these scaffolds is imperative for optimal control of glucose levels. We studied the effect of the vascular stimulator hydrogen sulfide (H2S) on the degree of vascularization of a scaffold and the role of the immune system in this process. Scaffolds were subcutaneously implanted in immunocompetent C57BL/6 and immunocompromised nude mice. Mice received twice-daily intraperitoneal injections of the fast-releasing H2S donor sodium hydrosulfide (NaHS, 25 or 50 μmol/kg) or saline for 28 days. After 63 days the vascular network was analyzed by histology and gene expression. Here we showed that the vascularization of a subcutaneous scaffold in nude mice was significantly impaired by H2S treatment. Both the CD31 gene and protein expression were reduced in these scaffolds compared to the saline-treated controls. In C57BL/6 mice, the opposite was found, the vascularization of the scaffold was significantly increased by H2S. The mRNA expression of the angiogenesis marker CD105 was significantly increased compared to the controls as well as the number of CD31 positive blood vessels. In conclusion, the immune system plays an important role in the H2S mediated effect on vascularization of subcutaneous scaffolds.

Treatment with slow-releasing hydrogen sulfide donors inhibits the nociceptive and depressive-like behaviours accompanying chronic neuropathic pain: Endogenous antioxidant system activation.

Therapies to treat chronic neuropathic pain and its associated comorbidities are limited. Recent studies demonstrated that the administration of slow-releasing hydrogen sulfide (H2S) donors inhibited chemotherapy-induced neuropathic pain. However, the antidepressant or anxiolytic effects of these compounds and their mechanisms of action during chronic neuropathic pain have not been evaluated. To determine whether the administration of two slow-releasing H2S donors, allyl isothiocyanate (A-ITC) and phenyl isothiocyanate (P-ITC), inhibits the nociceptive and emotional disorders associated with chronic neuropathic pain. In C57BL/6 male mice with neuropathic pain caused by the chronic constriction of the sciatic nerve, we assessed the effects of intraperitoneal administration of A-ITC and P-ITC in (a) the mechanical allodynia, thermal hyperalgesia and thermal allodynia induced by nerve ligation; (b) the anxiety- and depressive-like behaviours linked with neuropathic pain; (c) glial activation and mitogen-activated protein kinases phosphorylation, and (d) expression of the antioxidant enzymes, heme oxygenase 1 (HO-1), NADPH quinone oxidoreductase1, and glutathione S-transferase mu-1 (GSTM1), and alpha-1 (GSTA1), in hippocampus and prefrontal cortex (PFC). Both treatments inhibited the allodynia and hyperalgesia, depressive-like behaviours, astroglial activation, and the extracellular signal-regulated kinase 1/2 phosphorylation but were unable to abolish the anxiety-like behaviours accompanying neuropathic pain. A-ITC and P-ITC also augmented the expression of HO-1, GSTM1, and GSTA1 in the hippocampus and/or PFC. The administration of slow-releasing H2S donors might be a promising treatment for the management of chronic neuropathic pain and some associated comorbidities via inhibiting the inflammatory and plasticity changes, and activating the endogenous antioxidant responses.

The Physiology of Sphincter and Dilator Muscles in the Regulation of Intraocular Pressure

Iris is a small pigmented sheet in between cornea and the lens that is constantly bathed in aqueous humor. Two sets of muscles that are opposite in their function constitute the iris (sphincter for contraction, and the dilator for dilation) and these muscles are responsible for maintaining the normal size of the pupil. Thus, their proper functioning is important for iris health. Common manifestations that lead to secondary glaucomatous conditions include iritis, and anterior uveitis. Uveitis, a sight‐threatening emergency is responsible for more than 30,000 legal blinding in the US alone, and it accounts for 10–15% of blindness. The cause of most uveitis cases is idiopathic. Although homocysteine (Hcy), and the high glucose contribute to ocular dysfunction, but the mechanisms are not clear. This study investigated the role of Hcy, and the hyperglycemia (HG), and their contribution to the biology of sphincter, and dilator muscles in the regulation of intraocular pressure (IOP). We hypothesize that metabolic dysregulation of iris muscles during hyperhomocysteinemia (HHcy), and or HG is responsible for ocular hypertension. Therefore, restoration of the iris homeostasis by direct pharmacological intervention (e.g. dilator/constrictor/antioxidants: such as Tropicamide, acetylcholine, sodium nitroprusside, epinephrine, norepinephrine, glycol and atropine derivatives, and hydrogen sulfide donor; GYY 4137) could help modulate the pressure in the eye. When tested, as eye drops, employing Ins2Akita, and CBS+/− strains of mouse models representing HHcy, and HG conditions, the IOP was measured before, and after the application of above agents in treated, and untreated mice groups. Findings reveal that Tropicamide was more effective than others. Some agents, not all, were able to lower IOP significantly in a gender‐specific manner. We are currently dissecting‐out the molecular mechanism(s) that might reveal new therapeutic targets for treating the hypertensive eyes.Interestingly, both strains of the mice also revealed alterations in their retinae that included occlusion of their vessels along with significant thickening of the retinal layers. Our study has a direct clinical significance where dysfunction of the iris muscles alone or in conjunction with retinal‐ischemia may predispose susceptible patients to higher IOP that is responsible for various forms of glaucomatous phenotypes.

Comparison of Various Aryl-Dithiolethiones and Aryl-Dithiolones As Hydrogen Sulfide Donors in the Presence of Rat Liver Microsomes.

It has been reported that microsomal metabolism of ADT (5-(p-methoxyphenyl)-3H-1,2-dithiole-3-thione, anetholedithiolethione, Sulfarlem) and ADO (5-(p-methoxyphenyl)-3H-1,2-dithiole-3-one, anetholedithiolone) led to formation of H2S mainly derived from oxidations catalyzed by cytochrome P450-dependent monooxygenases and that ADO was a better H2S donor than ADT under these conditions. This article compares the H2S donor abilities of 18 dithiolethione and dithiolone analogs of ADT and ADO upon incubation with rat liver microsomes. It shows that, for all the studied compounds, maximal H2S formation was obtained after incubation with microsomes and NADPH and that this formation greatly decreased in the presence of N-benzylimidazole, a known inhibitor of cytochrome P450. This indicates that H2S formation from all the studied compounds requires, as previously observed in the case of ADT and ADO, oxidations catalyzed by cytochrome P450-dependent monooxygenases. Under these conditions, the studied dithiolones were almost always better H2S donors than the corresponding dithiolethiones. Interestingly, the best H2S yields (up to 75%) were observed in microsomal oxidation of ADO and its close analogs, pCl-Ph-DO and Ph-DO, in the presence of glutathione (GSH), whereas only small amounts of H2S were formed in microsomal incubations of those compounds with GSH but in the absence of NADPH. A possible mechanism for this effect of GSH is proposed on the basis of results obtained from reactions of GSH with 5-(p-methoxyphenyl)-3H-1,2-dithiole-3-one-1-sulfoxide, the ADO metabolite involved in H2S formation in microsomal oxidation of ADO. SIGNIFICANCE STATEMENT: A series of 18 dithiolethiones and dithiolones were compared for their ability to form hydrogen sulfide (H2S) in oxidations catalyzed by microsomal monooxygenases. The studied dithiolones were better H2S donors than the corresponding dithiolethiones, and the addition of glutathione to the incubations strongly increased H2S formation. A possible mechanism for this effect of GSH is proposed on the basis of results obtained from reactions of GSH with 5-(p-methoxyphenyl)-3H-1,2-dithiole-3-one-1-sulfoxide, a metabolite of the choleretic and sialologic drug Sulfarlem.

Exogenous hydrogen sulfide donor NaHS alleviates nickel-induced epithelial-mesenchymal transition and the migration of A549cells by regulating TGF-β1/Smad2/Smad3 signaling.

Nickel compounds are known to be common environmental and occupational carcinogens which also promote the migration of lung cancer cells. However, the molecular mechanism yet remains to be clarified. Hydrogen sulfide (H2S) is involved in cancer biological processes. However, the exact effect and functionality of H2S on nickel, towards the promotion of the migration ability of lung cancer cells, remains to be unknown. In this study, we have found that the nickel chloride (NiCl2) treatment significantly downregulates the protein levels of endogenous H2S enzyme cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-Mercaptopyruvate sulfurtransferase (3-MST). A correlation between NiCl2-induced epithelial-mesenchymal transition (EMT) and the migration ability of lung cancer A549cells has been observed. Exogenous H2S donor, sodium hydrogen sulfide (NaHS) (100μmol/L), can reverse NiCl2-induced EMT as well as the migration ability of A549cells. NiCl2 treatment is able to upregulate the protein level of transforming growth factor-β1 (TGF-β1), p-Smad2, p-Smad3, p-JNK, p-ERK and p-P38 in a time-dependent fashion, indicating that both TGF-β1/Smad2/Smad3 and mitogen-activated protein kinase (MAPK) signaling cascades (a non-Smad pathway) may play essential roles in NiCl2-dependent EMT as well as cell migration of human lung cancer cells. Furthermore, exogenous NaHS alleviates the NiCl2-induced EMT and the migration ability of A549cells only by regulating TGF-β1/Smad2/Smad3, rather than the MAPK, signaling pathway. These results indicate that the exogenous administration of NaHS might be a potential therapeutic strategy against nickel-induced lung cancer progression.

H2S counteracts proinflammatory effects of LPS through modulation of multiple pathways in human cells.

Hydrogen sulfide donors reduce inflammatory signaling in vitro and in vivo. The biological effect mediated by H2S donors depends on the kinetics of the gas release from the donor molecule. However, the molecular mechanisms of H2S-induced immunomodulation were poorly addressed. Here, we studied the effect of two different hydrogen sulfide (H2S)-producing agents on the generation of the LPS-induced inflammatory mediators. Importantly, we investigated the transcriptomic changes that take place in human cells after the LPS challenge, combined with the pretreatment with a slow-releasing H2S donor-GYY4137. We investigated the effects of GYY4137 and sodium hydrosulfide on the release of proinflammatory molecules such as ROS, NO and TNF-α from LPS-treated human SH-SY5Y neuroblastoma and the THP-1 promonocytic cell lines. Transcriptomic and RT-qPCR studies using THP-1 cells were performed to monitor the effects of the GYY4137 on multiple signaling pathways, including various immune-related and proinflammatory genes after combined action of LPS and GYY4137. The GYY4137 and sodium hydrosulfide differed in the ability to reduce the production of the LPS-evoked proinflammatory mediators. The pre-treatment with GYY4137 resulted in a drastic down-regulation of many TNF-α effectors that are induced by LPS treatment in THP-1 cells. Furthermore, GYY4137 pretreatment of LPS-exposed cells ameliorates the LPS-mediated induction of multiple pro-inflammatory genes and decreases expression of immunoproteasome genes. Besides, in these experiments we detected the up-regulation of several important pathways that are inhibited by LPS. Based on the obtained results we believe that our transcriptomic analysis significantly contributes to the understanding of the molecular mechanisms of anti-inflammatory and cytoprotective activity of hydrogen sulfide donors, and highlights their potential against LPS challenges and other forms of inflammation.

Evaluation of combined therapeutic effects of hydrogen sulfide donor sodium hydrogen sulfide and phosphodiesterase type-5 inhibitor tadalafil on erectile dysfunction in a partially bladder outlet obstructed rat model.

To evaluate the impacts of hydrogen sulfide (H2 S) donor, sodium hydrogen sulfide (NaHS), and phosphodiesterase type-5 inhibitor (PDE5i), tadalafil per se and their combination treatment on partial bladder outlet obstruction (PBOO)-induced erectile dysfunction (ED). Sprague-Dawley rats were equally divided into five groups: (a) sham-operated control; (b) PBOO; (c) PBOO-treated with NaHS (5.6 mg/kg/day, ip); (d) PBOO-treated with tadalafil (2 mg/kg/day, oral); and (e) PBOO-treated with combination of NaHS and tadalafil. The obstruction was created by urethral ligation for 6 weeks. In vivo erectile responses, in vitro relaxant and contractile responses in penile tissue as well as protein expression of nitric oxide synthases (NOS), H2 S synthesis enzymes, oxidative stress, hypoxia, fibrosis markers, and the smooth muscle/collagen ratio and apoptosis were analyzed. Combined treatment entirely returned increased bladder mass, reduced erectile responses, relaxation responses to acetylcholine, and electrical field stimulation in obstructed rats, while partial amelioration was observed after mono-treatment. Decreased neuronal NOS and 3-mercaptopiruvate transferase enzyme expressions in penile tissue from obstructed rats were also entirely restored by the combined treatment. Mono-treatment partially improved increased hypoxia, oxidative stress, fibrosis markers, decreased smooth muscle mass, and H2 S levels, while combined therapy completely recovered. The combination therapy with H2 S donor and PDE5i had positive effects on erectile responses through the improvement of ischemia-induced morphological and functional penile alterations in obstruction. H2 S and NO may likely play a synergistic role in the regulation of erectile function and have constructive effects on clinical outcomes in male patients with ED and benign prostatic hyperplasia/lower urinary tract symptoms.

Induction of caveolin-3/eNOS complex by nitroxyl (HNO) ameliorates diabetic cardiomyopathy

Nitroxyl (HNO), one-electron reduced and protonated sibling of nitric oxide (NO), is a potential regulator of cardiovascular functions. It produces positive inotropic, lusitropic, myocardial anti-hypertrophic and vasodilator properties. Despite of these favorable actions, the significance and the possible mechanisms of HNO in diabetic hearts have yet to be fully elucidated. H9c2 cells or primary neonatal mouse cardiomyocytes were incubated with normal glucose (NG) or high glucose (HG). Male C57BL/6 mice received intraperitoneal injection of streptozotocin (STZ) to induce diabetes. Here, we demonstrated that the baseline fluorescence signals of HNO in H9c2 cells were reinforced by both HNO donor Angeli's salt (AS), and the mixture of hydrogen sulfide (H2S) donor sodium hydrogen sulfide (NaHS) and NO donor sodium nitroprusside (SNP), but decreased by HG. Pretreatment with AS significantly reduced HG-induced cell vitality injury, apoptosis, reactive oxygen species (ROS) generation, and hypertrophy in H9c2 cells. This effect was mediated by induction of caveolin-3 (Cav-3)/endothelial nitric oxide (NO) synthase (eNOS) complex. Disruption of Cav-3/eNOS by pharmacological manipulation or small interfering RNA (siRNA) abolished the protective effects of AS in HG-incubated H9c2 cells. In STZ-induced diabetic mice, administration of AS ameliorated the development of diabetic cardiomyopathy, as evidenced by improved cardiac function and reduced cardiac hypertrophy, apoptosis, oxidative stress and myocardial fibrosis without affecting hyperglycemia. This study shed light on how interaction of NO and H2S regulates cardiac pathology and provide new route to treat diabetic cardiomyopathy with HNO.

Влияние газотрансмиттера сероводорода на микрореологические свойства эритроцитов здоровых лиц и больных сахарным диабетом второго типа

Цель исследования: изучение влияния донора газотрансмиттера (ГТ) сероводорода (NaНS) и активатора его внутриклеточного синтеза (Lцистеина) на микрореологические характеристики эритроцитов в норме и при сахарном диабете 2-го типа (СД2). Материалы и методы. Эритроциты 16 здоровых лиц и 16 больных СД2 инкубировали с донором сероводорода гидросульфидом натрия (NaHS) в концентрации 10, 50 и 100 мкмоль и стимулятором его эндогенного синтеза Lцистеином в концентрации 10, 50 и 100 мкмоль. Блокировали АТФзависимые калиевые каналы глибенкламидом (50 мкмоль). Ингибировали растворимую гуанилатциклазу с помощью 0,5 мкмоль ODQ (1H-1,2,4-oxadiazolo4,3-a quinoxalin-l-one). Регистрировали деформируемость (ИУЭ) и агрегацию эритроцитов. Результаты. Под влиянием NaHS наблюдали дозозависимые положительные изменения микрореологии эритроцитов. Микрореологические ответы эритроцитов на NaHS были более выраженными у здоровых лиц, чем у больных СД2. Сходную картину наблюдали и при воздействии на эритроциты Lцистеином. Прединкубация с глибенкламидом не устраняла положительного влияния донора ГТ на микрореологию эритроцитов, тогда как ингибирование растворимой гуанилатциклазы с помощью ODQ полностью устраняло положительные изменения ИУЭ под действием ГТ и существенно уменьшало его влияние на агрегацию клеток. Заключение. Таким образом, сероводород как газотрансмиттер улучшает микрореологию эритроцитов. При одинаковой концентрации донора сероводорода (NaHS) и стимулятора его синтеза (Lцистеина) более выраженные сдвиги микрореологических параметров эритроцитов наблюдаются у здоровых лиц по сравнению с больными СД2. Aim: to study the effect of donor gasotransmitter (GT) hydrogen sulphide (NaHS) and the activator of its intracellular synthesis (Lcysteine) on the red blood cells (RBCs) microrheological characteristics in normal and diabetes mellitus type 2 (DM2). Materials and methods. RBCs of 16 healthy individuals and 16 patients with DM2 were incubated with hydrogen sulfide donor sodium hydrosulfide (NaHS) in concentrations of 10, 50 and 100 mol and a stimulator of its endogenous synthesis Lcysteine (10, 50 and 100 mol). ATPdependent potassium channels were blocked by glibenclamide (50 mol). Soluble guanylate cyclase was inhibited using 0.5 mol ODQ (1H-1,2,4-oxadiazolo4,3-a quinoxalin-l-one). Deformability (RBCD) and RBCs aggregation were recorded. Results. Under the influence of NaHS, dose-dependent positive changes in RBCs microrheology were observed. Cellular microrheological responses to GT donor were more pronounced in healthy individuals than in patients with DM2. A similar pattern was observed when RBCs were exposed to Lcysteine. Preincubation with glibenclamide did not eliminate the positive effect of GT donor on RBCs microrheology. Whereas inhibition of soluble guanylate cyclase with the help of ODQ completely eliminated positive changes in RBCD under the action of GT and significantly reduced its effect on aggregation. Conclusion. Thus, hydrogen sulfide as a gasotransmitter improves RBCs microrheology. With the same concentration of hydrogen sulphide donor (NaHS) and its synthesis stimulator (Lcysteine), more pronounced shifts in the microrheological parameters of erythrocytes are observed in healthy individuals as compared with DM2 patients.

Involvement of the JIN1/MYC2 Transcription Factor in Inducing Salt Resistance in Arabidopsis Plants by Exogenous Hydrogen Sulfide

The JIN1/MYC2 transcription factor, which is currently considered to be the key in jasmonate signaling, is also involved in the transduction of abscisic acid signals and, probably, in the effects of other intermediaries involved in the formation of plants’ adaptive responses. Arabidopsisjin1 mutants were used to study its possible involvement in protective effects of hydrogen sulfide (H2S) against salt stress. The treatment of wild-type Arabidopsis plants (Col-0) with the donor of hydrogen sulfide (50 μmol NaHS) led to an increase in their salt resistance, which was expressed in a decrease in oxidative damages, a decrease in water deficit, and preservation of a pool of photosynthetic pigments under 150 mmol NaCl. The treatment of Col-0 plants with NaHS prevented the stress-induced decrease in the activity of antioxidant enzymes, i.e., superoxide dismutase and catalase, and contributed to the increase in the activity of guaiacol peroxidase. In addition, leaves’ proline content in wild-type plants treated with the H2S donor was lower and sugar was higher after salt stress than in untreated plants. The treatment of jin1 mutants did not contribute to their salt resistance and did not have a noticeable effect on the functioning of the studied protective systems. The obtained results make it possible to assume the involvement of the JIN1/MYC2 transcription factor in the effects of hydrogen sulfide and/or intermediaries of its signaling pathways involved in the formation of plants’ adaptive responses to salt stress.

Diallyl trisulfide, a H2 S donor, inhibits cell growth of human papillary thyroid carcinoma KTC-1 cells through a positive feedback loop between H2 S and cystathionine-gamma-lyase.

Diallyl trisulfide (DATS), derived from garlic, is a well-known hydrogen sulfide (H2 S) donor. H2 S has recently emerged as a novel gasotransmitter involved in the regulation of cancer progression. The present study demonstrated that DATS along with other two H2 S donors, NaHS and GYY4137, significantly inhibited papillary thyroid carcinoma KTC-1 cells growth. DATS treatment triggered a rapid H2 S generation within 5 min in KTC-1 cells. Iodoacetamide, a potent thiol blocker reagent, partially rescued the cell membrane damage and ultimate cell death induced by DATS, indicating H2 S contributed to the apoptosis-inducing efficacy of DATS on thyroid cancer cells. Specifically, DATS treatment significantly upregulated the expression and enzymatic activity of cystathionine gamma-lyase (CTH), one of H2 S-producing enzymes, which was responsible for endogenous H2 S generation. After DATS treatment, H2 S quickly permeated cell membranes and activated NF-κΒ/p65 signaling pathway in KTC-1 cells. Nuclear translocated NF-κB bound to the promoter of CTH to enhance its transcription. These evidences proved that exogenous H2 S elevated CTH expression. CTH, in turn, catalytically generated a much higher level of endogenous H2 S. This positive feedback sustained excess H2 S production, which resulted in PTC cells growth inhibition. These findings may shed light on the development of novel H2 S-based antitumor agents.

A novel carbazole-based hydrogen-sulfide donor suppresses seizures and upregulates ATP-sensitive potassium channels

Epilepsy is characterized by repeated spontaneous seizures and remains untreatable due to its complicate pathogenesis. Low-dose hydrogen sulfide (H2S) has been shown to exert antiepileptic and protective effects in the central nervous system, but the administration of H2S gas to suppress seizures is difficult. In the present study, we synthesized a safe and efficient carbazole-based H2S donor from aldehydes with a one-pot procedure and characterized this specific H2S donor via proton nuclear magnetic resonance (1HNMR), scanning electron microscopy (SEM), and absorption spectroscopy. In vitro and in vivo risk assessments demonstrated that the H2S donor (up to a 400-μM concentration) had sufficient biocompatibility and membrane permeability and suppressed epileptic seizures. Importantly, the suppression of seizures was determined in the brain when the H2S donor was injected into the lateral ventricle in a rat model of advanced seizures. Furthermore, the mechanism by which the H2S donor suppressed the expression of seizures may have been related to H2S donor-induced increases in the expressions of the ATP-sensitive potassium channel (KATP) subunits, Kir6.2 and SUR1. Taken together, these assays suggested that our novel H2S donor may represent a potential therapeutic strategy for ameliorating seizures in epilepsy.

Exogenous hydrogen sulfide alleviates surgery-induced neuroinflammatory cognitive impairment in adult mice by inhibiting NO signaling

BackgroundTo investigate the effect and mechanisms of exogenous hydrogen sulfide in surgery-induced neuroinflammatory cognitive dysfunction.MethodsC57BL/6 J male mice (n = 140) were used and randomly divided into seven groups: the sham group, surgery group, GYY4137 group, L-NAME group, surgery+GYY4137 group, surgery +L-NAME group, and surgery+GYY4137 + L-NAME group. After the interventions, open field tests (OFT) and the Morris water maze (MWM) test were conducted to evaluate learning and memory abilities in the mice. ELISAs, nitrate reductase assays, and Western blots (WB) were conducted to evaluate interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), inducible nitric oxide synthase (iNOS), malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase (SOD) levels. Furthermore, the expression level of microglial marker ionized calcium binding adaptor molecule 1 (IBA) in the hippocampal CA1 and CA3 areas was detected by an immunohistochemical (IHC) assay and apoptotic cells were observed using terminal deoxynucleotidyl transferase dUTP end-labeling (TUNEL) staining kits.ResultsWe found that surgery induced neuroinflammatory cognitive dysfunction, oxidative stress, microglial activation, and cell apoptosis in the hippocampus. Moreover, following surgery, NO and iNOS levels were elevated in the hippocampus. Notably, all the effects caused by surgery were reversed by the H2S donor GYY4137 or the iNOS inhibitor N(gamma)-nitro-L-arginine methyl ester (L-NAME). However, the combined application of GYY4137 and L-NAME was not superior to treatment with either agent alone and the effect of GYY4137 was similar to that of L-NAME.ConclusionThe long-acting hydrogen sulfide donor GYY4137 had an ability to reversed the cognitive deficits and inflammation caused by carotid artery exposure surgery. This implies that NO signaling pathways might participate in this process. These results indicate that exogenous H2S may be a promising therapy for POCD.

The slow releasing hydrogen sulfide donor GYY4137 reduces neointima formation upon FeCl3 injury of the carotid artery inmice.

Neointima formation is closely linked to vascular stenosis and occurs after endothelial damage. Hydrogen sulfide is an endogenous pleiotropic mediator with numerous positive effects on the cardio vascular system. This study evaluates the effect of the slow releasing hydrogen sulfide donor GYY4137 (GYY) on neointimal formation in vivo. The effect of GYY on neointimal formation in the carotid artery was studied in the FeCl3 injury model in GYY- or vehicle-treated mice. The carotid arteries were studied at days 7 and 21 after treatment by means of histology and immunohistochemistry for proliferating cell nuclear antigen (PCNA) and alpha smooth muscle actin (α-SMA). GYY treatment significantly reduced the maximal diameter and the area of the newly formed neointima on both days 7 and 21 when compared to vehicle treatment. GYY additionally reduced the number of PCNA- and α-SMA-positive cells within the neointima on day 21 after FeCl3 injury of the carotid artery. Summarizing, single treatment with the slow releasing hydrogen sulfide donor GYY reduced the extent of the newly formed neointima by affecting the cellular proliferation at the site of vascular injury.

Assessment of the effect of sodium hydrogen sulfide (hydrogen sulfide donor) on cisplatin-induced testicular toxicity in rats.

Cisplatin (CIS) is an antineoplastic drug able to produce free radicals that are capable to induce various side effects in different tissues. Hydrogen sulfide (H2S) has notable antioxidant, anti-apoptotic, and anti-inflammatory effects in different systems but its role in male reproductive system is not fully understood. In the present research, the effect of sodium hydrosulfide (NaHS) on cisplatin-induced testicular toxicity in male rats was studied. Thirty-two Sprague-Dawley rats were equally divided into 4 groups. The control group was treated with normal saline by intraperitoneal injection. The NaHS group received NaHS (200μg/kg/day) intraperitoneally for 15days. The CIS group received single dose of cisplatin (5mg/kg) intraperitoneally, while the combination of CIS and NaHS was given to the CIS+ NaHS group. At the end of the study, body and testicular weights, plasma testosterone level, histological and morphometrical alterations, inflammation via IL-1β protein, lipid peroxidation, and activity of antioxidant enzymes (including glutathione peroxidase, superoxide dismutase, and catalase) of testicular tissue were evaluated. CIS injection revealed a significant decrease (p < 0.01) in body and testis weights, plasma testosterone concentration, diameter of seminiferous tubules, germinal epithelium thickness, the number of Sertoli cells, spermatogonia and spermatocyte, Johnsen's testicular score, and testicular antioxidant enzymes, whereas it caused a significant increase (p < 0.01) in lumen diameter of the seminiferous tubules, level of lipid peroxidation, and IL-1β protein expression when compared with the control group. NaHS administration to CIS-treated rats provided marked improvement (p < 0.05) in all biochemical, histological, and morphometrical changes induced by CIS. The beneficial effects of NaHS were mediated, at least partly, by its antioxidant and anti-inflammatory properties.

Effects of the Hydrogen Sulfide Donor GYY4137 and HSP70 Protein on the Activation of SH-SY5Y Cells by Lipopolysaccharide

The effects of exogenous recombinant human heat shock protein Hsp70 and hydrogen sulfide donor GYY4137 on the mechanisms of endocytosis of lipopolysaccharide (LPS) by human neuroblastoma cells SH-SY5Ywas studied. Hsp70 and GYY4137 have been shown to significantly reduce LPS-induced production of inflammatory mediators by SH-SY5Y cells, including reactive oxygen species, nitric oxide, TNFα, IL-1β, and IL-6. Both the recombinant protein Hsp70 and the hydrogen sulfide donor GYY4137 exhibited significant protective effects; however, the combined use of these agents did not lead to a cumulative effect. It has been shown that pinocytosis, as well as clathrin-, caveolin-, tubulin- and receptor-dependent endocytosis were involved in protecting the cells by both the hydrogen sulfide donor and Hsp70 from LPS-induced production of reactive oxygen species and NO.