NaHS Research Articles

Hydrogen sulfide attenuates TMAO‑induced macrophage inflammation through increased SIRT1 sulfhydration.

Chronic inflammation is a key factor that accelerates the progression of inflammatory vascular disease. Hydrogen sulfide (H2S) has potent anti‑inflammatory effects; however, its underlying mechanism of action has not been fully elucidated. The present study aimed to investigate the potential effect of H2S on sirtuin 1 (SIRT1) sulfhydration in trimethylamine N‑oxide (TMAO)‑induced macrophage inflammation, and its underlying mechanism. Pro‑inflammatory M1 cytokines (MCP‑1, IL‑1β, and IL‑6) and anti‑inflammatory M2 cytokines (IL‑4 and IL‑10) were detected by RT‑qPCR. CSE, p65 NF‑κB, p‑p65 NF‑κB, IL‑1β, IL‑6 and TNF‑α levels were measured by Western blot. The results revealed that cystathionine γ‑lyase protein expression was negatively associated with TMAO‑induced inflammation. Sodium hydrosulfide (a donor of H2S) increased SIRT1 expression and inhibited the expression of inflammatory cytokines in TMAO‑stimulated macrophages. Furthermore, nicotinamide, a SIRT1 inhibitor, antagonized the protective effect of H2S, which contributed to P65 NF‑κB phosphorylation and upregulated the expression of inflammatory factors in macrophages. H2S ameliorated TMAO‑induced activation of the NF‑κB signaling pathway via SIRT1 sulfhydration. Moreover, the antagonistic effect of H2S on inflammatory activation was largely eliminated by the desulfhydration reagent dithiothreitol. These results indicated that H2S may prevent TMAO‑induced macrophage inflammation by reducing P65 NF‑κB phosphorylation via the upregulation and sulfhydration of SIRT1, suggesting that H2S may be used to treat inflammatory vascular diseases.

Fast and slow releasing sulphide donors engender distinct transcriptomic alterations in Atlantic salmon hepatocytes

Hydrogen sulphide (H2S) is a naturally occurring compound generated either endogenously or exogenously and serves both as a gaseous signalling molecule and an environmental toxicant. Though it has been extensively investigated in mammalian systems, the biological function of H2S in teleost fish is poorly identified. Here we demonstrate how exogenous H2S regulates cellular and molecular processes in Atlantic salmon (Salmo salar) using a primary hepatocyte culture as a model. We employed two forms of sulphide donors: the fast-releasing salt form, sodium hydrosulphide (NaHS) and the slow-releasing organic analogue, morpholin-4-ium 4-methoxyphenyl(morpholino) phosphinodithioate (GYY4137). Hepatocytes were exposed to either a low (LD, 20 µg/L) or high (HD, 100 µg/L) dose of the sulphide donors for 24 hrs, and the expression of key sulphide detoxification and antioxidant defence genes were quantified by qPCR. The key sulphide detoxification genes sulfite oxidase 1 (soux) and the sulfide: quinone oxidoreductase 1 and 2 (sqor) paralogs in salmon showed pronounced expression in the liver and likewise responsive to the sulphide donors in the hepatocyte culture. These genes were ubiquitously expressed in different organs of salmon as well. HD-GYY4137 upregulated the expression of antioxidant defence genes, particularly glutathione peroxidase, glutathione reductase and catalase, in the hepatocyte culture. To explore the influence of exposure duration, hepatocytes were exposed to the sulphide donors (i.e., LD versus HD) either transient (1h) or prolonged (24h). Prolonged but not transient exposure significantly reduced hepatocyte viability, and the effects were not dependent on concentration or form. The proliferative potential of the hepatocytes was only affected by prolonged NaHS exposure, and the impact was not concentration dependent. Microarray analysis revealed that GYY4137 caused more substantial transcriptomic changes than NaHS. Moreover, transcriptomic alterations were more marked following prolonged exposure. Genes involved in mitochondrial metabolism were downregulated by the sulphide donors, primarily in NaHS-exposed cells. Both sulphide donors influenced the immune functions of hepatocytes: genes involved in lymphocyte-mediated response were affected by NaHS, whereas inflammatory response was targeted by GYY4137. In summary, the two sulphide donors impacted the cellular and molecular processes of teleost hepatocytes, offering new insights into the mechanisms underlying H2S interactions in fish.

Soybean (Glycine max L.) Lipoxygenase 1 (LOX 1) Is Modulated by Nitric Oxide and Hydrogen Sulfide: An In Vitro Approach.

Hydrogen sulfide (H2S) and nitric oxide (NO) are two relevant signal molecules that can affect protein function throughout post-translational modifications (PTMs) such as persulfidation, S-nitrosation, metal-nitrosylation, and nitration. Lipoxygenases (LOXs) are a group of non-heme iron enzymes involved in a wide range of plant physiological functions including seed germination, plant growth and development, and fruit ripening and senescence. Likewise, LOXs are also involved in the mechanisms of response to diverse environmental stresses. Using purified soybean (Glycine max L.) lipoxygenase type 1 (LOX 1) and nitrosocysteine (CysNO) and sodium hydrosulfide (NaHS) as NO and H2S donors, respectively, the present study reveals that both compounds negatively affect LOX activity, suggesting that S-nitrosation and persulfidation are involved. Mass spectrometric analysis of nitrated soybean LOX 1 using a peroxynitrite (ONOO-) donor enabled us to identify that, among the thirty-five tyrosine residues present in this enzyme, only Y214 was exclusively nitrated by ONOO-. The nitration of Y214 seems to affect its interaction with W500, a residue involved in the substrate binding site. The analysis of the structure 3PZW demonstrates the existence of several tunnels that directly communicate the surface of the protein with different internal cysteines, thus making feasible their potential persulfidation, especially C429 and C127. On the other hand, the CysNO molecule, which is hydrophilic and bulkier than H2S, can somehow be accommodated throughout the tunnel until it reaches C127, thus facilitating its nitrosation. Overall, a large number of potential persulfidation targets and the ease by which H2S can reach them through the diffuse tunneling network could be behind their efficient inhibition.

Exogenous Hydrogen Sulfide Activates PI3K/Akt/eNOS Pathway to Improve Replicative Senescence in Human Umbilical Vein Endothelial Cells.

Endothelial cell senescence is one of the key mechanistic factors in the pathogenesis of atherosclerosis. In terms of molecules, the phosphatidylinositol 3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) signaling plays an important role in the prevention and control of endothelial cell senescence, while hydrogen sulfide (H2S) improves the induced precocious senescence of endothelial cells through the PI3K/Akt/eNOS pathway. Comparatively, replicative senescence in endothelial cells is more in line with the actual physiological changes of human aging. This study aims to investigate the mechanism by which H2S improves endothelial cell replicative senescence and the involvement of the PI3K/Akt/eNOS pathway. we established a model of replicative senescence in human umbilical vein endothelial cells (HUVECs) and explored the effect of 200 μmol/L sodium hydrosulfide (NaHS; a donor of H2S) on senescence, which was determined by cell morphology, the expression level of plasminogen activator inhibitor 1 (PAI-1), and the positive rate of senescence-associated β-galactosidase (SA-β-Gal) staining. Cell viability was detected by MTT assay to evaluate the effect of NaHS and the PI3K inhibitor, LY294002. Meanwhile, the protein expression of PI3K, Akt, p-Akt, and eNOS in endothelial cells of each group was detected by Western blot. the replicative senescence model was established in HUVECs at the passage of 16 cumulative cell population doubling values (CPDL). Treatment with NaHS not only significantly reduced the expression of PAI-1 and the positive rate of SA-β-Gal in HUVEC's replicative senescence model but also notably increased the expression of PI3K, p-Akt, p-eNOS, and the content of nitric oxide(NO). However, the effects of NaHS on the expression of the pathway and the content of NO in HUVECs were abolished when LY294002 specifically inhibited PI3K. NaHS improves the replicative senescence of HUVECs with the contribution of the PI3K/Akt/eNOS pathway.

Hepatic and cardiac implications of increased toxic amyloid-beta serum level in lipopolysaccharide-induced neuroinflammation in rats: new insights into alleviating therapeutic interventions

Neuroinflammation is a devastating predisposing factor for Alzheimer’s disease (AD). A number of clinical findings have reported peripheral disorders among AD patients. Amyloid beta (Aβ) is a toxic physiological aggregate that serves as a triggering factor for hepatic and cardiac disorders related to neurotoxicity. As a drawback of Aβ excessive accumulation in the brain, part of Aβ is believed to readily cross the blood–brain barrier (BBB) into the peripheral circulation resulting in serious inflammatory and toxic cascades acting as a direct bridge to cardiac and hepatic pathophysiology. The main aim is to find out whether neuroinflammation-related AD may result in cardiac and liver dysfunctions. Potential therapeutic interventions are also suggested to alleviate AD’s cardiac and hepatic defects. Male rats were divided into: control group I, lipopolysaccharide (LPS)-neuroinflammatory-induced group II, LPS-neuroinflammatory-induced group treated with sodium hydrogen sulphide donor (NaHS) (group III), and LPS-neuroinflammatory-induced group treated with mesenchymal stem cells (MSCs) (group IV). Behavior and histopathological studies were conducted in addition to the estimation of different biological biomarkers. It was revealed that the increased toxic Aβ level in blood resulted in cardiac and hepatic malfunctions as a drawback of exaggerated inflammatory cascades. The administration of NaHS and MSCs proved their efficiency in combating neuroinflammatory drawbacks by hindering cardiac and hepatic dysfunctions. The consistent direct association of decreased heart and liver functions with increased Aβ levels highlights the direct involvement of AD in other organ complications. Thereby, these findings will open new avenues for combating neuroinflammatory-related AD and long-term asymptomatic toxicity.Graphic abstract

Effect of hydrogen sulfide and hydrogen peroxide on growth, yield and nutrient content of broccoli plants grown under saline conditions

Salt stress is one of the most damaging abiotic stresses and is likely to worsen in arid and semi-arid regions under climate change, limiting plant production and reducing crop yields. This study was conducted in an open field in the desert under a saline environment, saline soil (9.68 dS.m−1) and saline irrigation water (7.12 dS.m−1), to evaluate the protective effects of H2O2 and H2S on broccoli, two levels of H2O2 (1, and 2 mmol. L−1), and two levels of sodium hydrosulfide (NaHS), H2S donor (0.1 and 0.2 mmol. L−1). Foliar application of either H2O2 or H2S was effective in mitigating the adverse effects of salt stress on growth and yield of broccoli. Chlorophyll (a and b), carotenoids, and APX were significantly increased in plants sprayed with H2S compared to those sprayed with H2O2, while SOD, POX, and CAT activities were greater in plants sprayed with H2O2. The largest decrease in malondialdehyde (MDA), H2O2, and Na accumulation was observed in plants treated with 0.2 mmol. L−1 H2S. Broccoli yield, nutritional content, and cell membrane stability index (CMSI) were increased with foliar treatments, all foliar treatments yielded larger and heavier broccoli heads than untreated plants. However, plants sprayed with 0.2 mmol. L−1 H2S showed the most promising results, significantly enhancing broccoli yield parameters in terms of head fresh weight (24.5%), head dry weight (19.2%), and head diameter (17.7%), and nutritional content such as vitamin C (16.8%) and total soluble solids (9.9%), as well as, leaf nutrient content in terms of N (21.2%) and K (15.6%), with decreasing sodium content by 20.3%. The results suggest that foliar spraying of H2O2 and H2S could be an effective physiological method to mitigate abiotic stress and improve plant growth and yield.

NaHS restores the vascular alterations in the renin-angiotensin system induced by hyperglycemia in rats

Hyperglycemia (HG) impairs the renin-angiotensin system (RAS), which may contribute to vascular dysfunction. Besides, hydrogen sulfide (H2S) exerts beneficial cardiovascular effects in metabolic diseases. Therefore, our study aimed to determine the effects of chronic administration of sodium hydrosulfide (NaHS; inorganic H2S donor) and DL-Propargylglycine [DL-PAG; cystathionine-ץ-lyase (CSE) inhibitor] on the RAS-mediated vascular responses impairments observed in thoracic aortas from male diabetic Wistar rats. For that purpose, neonatal rats were divided into two groups that received: 1) citrate buffer (n = 12) or 2) streptozotocin (STZ, 70 mg/kg; n = 48) on the third postnatal day. After 12 weeks, diabetic animals were divided into 4 subgroups (n = 12 each) that received daily i.p. injections during 4 weeks of: 1) non-treatment; 2) vehicle (PBS, 1 mL/kg); 3) NaHS (5.6 mg/kg); and 4) DL-PAG (10 mg/kg). After treatments (16 weeks), blood glucose, angiotensin-(1−7) [Ang-(1−7)], and angiotensin II (Ang II) levels, vascular responses to Ang-(1−7) and Ang II, and the expression of angiotensin AT1, AT2, and Mas receptors, angiotensin converting enzyme (ACE) and ACE type 2 (ACE2) were determined. HG induced: 1) increased blood glucose levels and expression of angiotensin II AT1 receptor; 2) impaired Ang-(1−7) and Ang II mediated vascular responses; 3) decreased angiotensin levels and expression of angiotensin II AT2 and angiotensin-(1−7) Mas receptors, and ACE2; and 4) no changes in ACE expression. Interestingly, NaHS, but not DL-PAG, reversed HG-induced impairments, except for blood glucose level changes. These results suggest that NaHS restores vascular function in streptozotocin-induced HG through RAS modulation.

Sodium hydrosulfide-mediated upregulation of nitrogen metabolism improves drought stress tolerance in pepper plants

Although hydrogen sulfide (H2S) has been proven to promote plant tolerance to abiotic stress (including drought), the specific mechanism by which H2S mediates this process remains uncertain. The aim of the study was to fill this knowledge gap by investigating the potential of sodium hydrosulfide (NaHS) to improve drought tolerance in pepper plants through upregulating nitrogen metabolism-related enzymes and to gain insights into plant responses to drought stress. Pepper (Capsicum annuum) plants were grown at 80% and 40% of full field capacity. Reduced water availability led to a drastic decline in plant dry weight, leaf water potential (ΨI), relative water content (RWC), PSII operation efficiency (chlorophyll fluorescence Fv/Fm ratio), and chlorophyll content. Soluble protein and leaf and root nitrogen (N) levels were also lowered. Simultaneously, drought has significantly increased the levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA), and resulted in increased content of nitrate (NO3-) and ammonium (NH4+). Also increased were the amount of free amino acid, soluble sugars, glycine betaine and free proline. The activities of peroxidase (POD), glutathione S-transferase (GST), and catalase (CAT) were elevated, as were those of endogenous hydrogen sulfide (H2S), L-cysteine desulfhydrase (L-DES), and methylglyoxal (MG). When 0.2 mM sodium dihydrosulfide (NaHS, a H2S donor) was sprayed on drought-affected plants, oxidative stress markers were reduced, as well as NO3-, NH4+ and free amino acid levels. Furthermore, NaHS improved endogenous H2S without changing L-DES activity. At the same time, NaHS activated nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT) and glutamine dehydrogenase (GDH) activities, as well as enzymes related to the glyoxalase system (Gly I and Gly II) thus improving nitrogen metabolism. This resulted in an increased plant growth, photosynthetic attributes, and N content. To demonstrate the causal role of H2S in drought tolerance, plants were administered an H2S scavenger, hypotaurine (HT), along with NaHS. HT treatment negated beneficial effects of NaHS by lowering H2S content without changing L-DES activity. Thus, exogenous application of NaHS could offer a simple and economical alternative for crop productivity in environments with restricted water supply.

Hydrogen sulfide alleviates beryllium sulfate-induced ferroptosis and ferritinophagy in 16HBE cells.

Beryllium sulfate (BeSO4 ) can result to lung injuries, such as leading to lipid peroxidation and autophagy, and the treatment of beryllium disease has not been well improved. Ferroptosis is a regulated cell death process driven by iron-dependent and lipid peroxidation, while ferritinophagy is a process mediated by nuclear receptor coactivator 4 (NCOA4), combined with ferritin heavy chain 1 (FTH1) degradation and release Fe2+ , which regulated intracellular iron metabolism and ferroptosis. Hydrogen sulfide (H2 S) has the effects of antioxidant, antiautophagy, and antiferroptosis. This study aimed to investigate the effect of H2 S on BeSO4 -induced ferroptosis and ferritinophagy in 16HBE cells and the underlying mechanism. In this study, BeSO4 -induced 16HBE cell injury model was established based on cellular level and pretreated with deferoxamine (DFO, a ferroptosis inhibitor), sodium hydrosulfide (NaHS, a H2 S donor), or NCOA4 siRNA and, subsequently, performed to detect the levels of lipid peroxidation and Fe2+ and the biomarkers of ferroptosis and ferritinophagy. More importantly, our research found that DFO, NaHS, or NCOA4 siRNA alleviated BeSO4 -induced ferroptosis and ferritinophagy by decreasing the accumulation of Fe2+ and lipid peroxides. Furthermore, the relationship between ferroptosis, ferritinophagy, H2 S, and beryllium disease is not well defined; therefore, our research is innovative. Overall, our results provided a new theoretical basis for the prevention and treatment of beryllium disease and suggested that the application of H2 S, blocking ferroptosis, and ferritinophagy may be a potential therapeutic direction for the prevention and treatment of beryllium disease.

Hydrogen sulfide delays yellowing and softening, inhibits nutrient loss in postharvest celery

Celery is an important leafy vegetable crop and is widely used in fresh food consumption and processing. Therefore, the preservation of fresh cut celery is warranted. As a food preservative, sodium hydrosulfide has been used to maintain postharvest quality of crops. However, the role of sodium hydrosulfide in the preservation of postharvest celery remains unclear. Here, by regulating endogenous hydrogen sulfide content with sodium hydrosulfide and hypotaurine, we evaluated the effects of sodium hydrosulfide on postharvest celery quality. Sodium hydrosulfide treatment promoted endogenous hydrogen sulfide accumulation by triggering AgLCD and AgSAT expression, as well as increased activity of L-cysteine desulfhydrase, D-cysteine desulfhydrase, O-acetylserine (thiol)lyase, and serine acetyltransferase. Simultaneously, sodium hydrosulfide treatment enhanced the expression of AgSOD1, AgPOD, and AgCAT, improved the activities of superoxide dismutase, peroxidase, and catalase, and inhibited the accumulation of malondialdehyde, hydrogen peroxide, and superoxide anion, thereby reducing electrolyte leakage of the cell membrane. AgPAL and AgCAD expressions were up-regulated, and phenylalanine ammonia-lyase and cinnamyl alcohol dehydrogenase activities were increased to promote lignin synthesis and alleviate the softening process. AgPAO and AgPPH expression was down-regulated, polyamine oxidases and pheophytinase activities were decreased to inhibit chlorophyll degradation and delay yellowing. Meanwhile, sodium hydrosulfide treatment effectively inhibited nutrient loss, including soluble sugar, soluble protein, vitamin C, carotenoids, and total phenols. Our findings suggest that hydrogen sulfide plays an essential role in delaying quality deterioration of postharvest celery, while sodium hydrosulfide treatment is a promising method for celery preservation.

Sodium hydrogen sulfide may not protect the kidney against ischemia/reperfusion damage in male and female rats.

Renal ischemia/reperfusion (IR) injury is a pathologic phenomenon that caused to increase risk of mortality. The main objective of this study was to investigate the effect of sodium hydrogen sulfide (NaHS) on renal IR injury in male and female rats. Fifty-eight male and female rats were randomized into 4 groups of control, sham, IR, and IR + NaHS. The IR was performed by 45 min of ischemia by vessel clamping followed by 24 h reperfusion. The NaHS (100 µmol/kg) treatment was applied 10 min prior to IR. Finally, after 24 h of reperfusion, the measurements were performed. The serum levels of blood urea nitrogen, creatinine, tissue level of malondialdehyde, and kidney tissue damage score (KTDS) were increased by IR. Urine volume, creatinine, and urea clearances decreased by IR. NaHS administration improved some parameters in males but exacerbated KTDS and serum markers related to renal function. Our data demonstrated that NaHS didn't protect female rats against renal IR injury. In males, it has null effects or just a few protective effects via antioxidant activity.

A Suggested Mechanism for Green Discoloration of the Postmortem Brain.

In the putrefied brain, the cortex and basal ganglia show dark-grayish to green discoloration due to sulfhemoglobin formed from hydrogen sulfide (H 2 S) produced by endogenous bacteria and hemoglobin. In this study, we propose and demonstrate another mechanism of green discoloration in the brain. The formalin-fixed brain of a cadaver donated for medical education with no putrefaction was used. Half of the brain was immersed in sodium hydrosulfide solution, to imitate the H 2 S produced by bacteria. This half showed greenish discoloration, mainly in the basal ganglia and cortex. The other half showed positive Perls' Prussian blue staining, mainly in the basal ganglia and cortex. The area of greenish discoloration due to H 2 S and the region positive for Perls' Prussian blue staining coincided. Tissue treatment with strong oxidizing agents is required to liberate heme iron. The positive Perls' Prussian blue staining in this study thus does not reflect heme iron. In conclusion, we considered that non-heme iron compounds physiologically present in the brain and H 2 S represent sources of putrefactive greenish discoloration in the brain.

Alleviating Air Pollutants Impact by Some Chemicals and Planting Distance off the Freeway and Their Effect on Pears Productivity and Fruit Quality

The goal of this study was to determine the effectiveness of exogenous application of some chemicals [Salicylic acid (SA; 200 and 400 mg/l), Ascorbic acid (AA; 1000 and 2000 mg/l), Proline (Pro; 100 and 200 mg/l), and Sodium hydrosulfide (NaHS; 250 and 500 M)] as well as planting distances (10 and 50 meters off the freeway) in alleviating air pollutants stress on "Le Conte" productivity and fruit quality of pears. During the 2019 & 2020 seasons, a study was accomplished at the 6th of October Agriculture Company. SA, AA, proline, and NaHS had a positive effect on reducing the fruit heavy metal content for the pear trees under stress. Also, SA (400 mg/l), AA, Pro (100 mg/l), and NaHS (500 μM) treatments were very helpful in increasing the tolerance index for air pollution (APTI) in pear leaves. Exogenous application of Pro, SA (200 mg/l), and AA (2000 mg/l) increased Pro in leaves. Pear trees' yield, fruit firmness, TSS, TSS/acid, V.C., total sugars, total phenolics, antioxidants, peroxidase, and superoxide dismutase were increased. Fruit from trees planted at 10 m deferred in ripening and had higher total phenolics, antioxidants, peroxidase, and superoxide dismutase.

A Water-Soluble Hydrogen Sulfide Donor Suppresses the Growth of Hepatocellular Carcinoma via Inhibiting the AKT/GSK-3β/β-Catenin and TGF-β/Smad2/3 Signaling Pathways.

Hepatocellular carcinoma (HCC) is a disease with high morbidity, high mortality, and low cure rate. Hyaluronic acid (HA) is widely adopted in tissue engineering and drug delivery. 5-(4-Hydroxyphenyl)-3H-1, 2-dithiol-3-thione (ADT-OH) is one of commonly used H2S donors. In our previous study, HA-ADT was designed and synthesized via coupling of HA and ADT-OH. In this study, compared with sodium hydrosulfide (NaHS, a fast H2S-releasing donor) and morpholin-4-ium (4-methoxyphenyl)-morpholin-4-ylsulfanylidenesulfido-λ5-phosphane (GYY4137, a slow H2S-releasing donor), HA-ADT showed stronger inhibitory effect on the proliferation, migration, invasion, and cell cycle of human HCC cells. HA-ADT promoted apoptosis by suppressing the expressions of phospho (p)-protein kinase B (PKB/AKT), p-glycogen synthase kinase-3β (GSK-3β), p-β-catenin, and also inhibited autophagy via the downregulation of the protein levels of p-Smad2, p-Smad3, and transforming growth factor-β (TGF-β) in human HCC cells. Moreover, HA-ADT inhibited HCC xenograft tumor growth more effectively than both NaHS and GYY4137. Therefore, HA-ADT can suppress the growth of HCC cells by blocking the AKT/GSK-3β/β-catenin and TGF-β/Smad2/3 signaling pathways. HA-ADT and its derivatives may be developed as promising antitumor drugs.

Effect of Hydrogen Sulfide on Essential Functions of Polymorphonuclear Leukocytes.

Impaired polymorphonuclear leukocyte (PMNL) functions contribute to increased infections and cardiovascular diseases in chronic kidney disease (CKD). Uremic toxins reduce hydrogen sulfide (H2S) levels and the anti-oxidant and anti-inflammatory effects of H2S. Its biosynthesis occurs as a side process of transsulfuration and in the disposal of adenosylhomocysteine, a transmethylation inhibitor and proposed uremic toxin. PMNL chemotaxis was measured by the under-agarose method, phagocytosis, and oxidative burst by flow cytometry in whole blood and apoptosis by determining DNA content by flow cytometry and morphological features by fluorescence microscopy. Sodium hydrogen sulfide (NaHS), diallyl trisulphide (DATS) and diallyl disulphide (DADS), cysteine, and GYY4137 were used as H2S-producing substances. Increased H2S concentrations did not affect chemotaxis and phagocytosis. NaHS primed PMNL oxidative burst activated by phorbol 12-myristate 13-acetate (PMA) or E. coli. Both DATS and cysteine significantly decreased E. coli-activated oxidative burst but had no effect on PMA stimulation. While NaHS, DADS, and cysteine attenuated PMNL apoptosis, GYY4137 decreased their viability. Experiments with signal transduction inhibitors suggest that the intrinsic apoptosis pathway is mainly involved in GYY4137-induced PMNL apoptosis and that GYY4137 and cysteine target signaling downstream of phosphoinositide 3-kinase.

Hydrogen sulfide alleviates lipopolysaccharide-induced myocardial injury through TLR4-NLRP3 pathway.

To investigate the effect of hydrogen sulfide (H2S) on myocardial injury in sepsis-induced myocardial dysfunction (SIMD), male C57BL/6 mice were intraperitoneally injected with lipopolysaccharide (LPS) (10 mg/kg, i.p.) to induce cardiac dysfunction without or with the H2S donor sodium hydrosulfide (NaHS) (50 µmol/kg, i.p.) administration 3 h after LPS injection. Six hours after the LPS injection, echocardiography, cardiac hematoxylin and eosin (HE) staining, myocardial damage and inflammatory biomarkers and Western blot results were analyzed. In mice, the administration of LPS decreased left ventricular ejection fraction (LVEF) by 30 % along with lowered H2S levels (35 % reduction). It was observed that cardiac troponin I (cTnI), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) levels were all increased (by 0.22-fold, 2000-fold and 0.66-fold respectively). HE staining revealed structural damage and inflammatory cell infiltration in the myocardial tissue after LPS administration. Moreover, after 6 h of LPS treatment, toll-like receptor 4 (TLR4) and nod-like receptor protein 3 (NLRP3) expressions were up-regulated 2.7-fold and 1.6-fold respectively. When compared to the septic mice, NaHS enhanced ventricular function (by 0.19-fold), decreased cTnI, TNF-alpha, and IL-1beta levels (by 11 %, 33 %, and 16 % respectively) and downregulated TLR4 and NLRP3 expressions (by 64 % and 31 % respectively). Furthermore, NaHS did not further improve cardiac function and inflammation in TLR4-/- mice or mice in which NLRP3 activation was inhibited by MCC950, after LPS injection. In conclusion, these findings imply that decreased endogenous H2S promotes the progression of SIMD, whereas exogenous H2S alleviates SIMD by inhibiting inflammation via the TLR4-NLRP3 pathway suppression.

The BDNF-TrkB signaling pathway is partially involved in the neuroprotective effects of hydrogen sulfide in Parkinson's disease

Recent studies have demonstrated that hydrogen sulfide (H2S) has a neuroprotective effect in neurodegenerative diseases. It is possible that this effect is supported by brain-derived neurotrophic factor (BDNF). Our aim is to examine the effects of H2S on neural damage in Parkinson's disease (PD) and to reveal the role of the BDNF-TrkB pathway in its possible effect. PD model was created with 1-methyl-phenyl-1,2,3,6-tetrahydropyridine (MPTP). C57BL/6 breed male mice were randomly divided into six groups: control, K252a, MPTP, MPTP + K252a, MPTP + NaHS, and MPTP + NaHS + K252a. TrkB receptor antagonist K252a and sodium hydrosulfide (NaHS) as a H2S donor were administered intraperitoneally. An increase was observed in the motor behavior tests in MPTP group, but NaHS treatment shortened the time spent on the balance beam and pole tests. It was also noticed that the BDNF-pathway played a role in the shortening of this period. Mice that received NaHS were found to have less MPTP-induced cellular damage. A positive effect of BDNF was also detected in the protection of these neurons. BDNF levels in the SN were significantly increased in MPTP group, compared to control group. Tissue CBS levels decreased in the groups that received K252a, compared to MPTP group. The findings of the present study display that the BDNF-TrkB pathway partially plays a role in the protective effect of H2S in the experimental mouse model of PD. This effect is probably due to changes in intracellular signaling pathways, rather than TrkB receptor expression.

Effect and mechanism of NaHS on tobacco bacterial wilt caused by Ralstonia solanacearum

Since its discovery as a third unique gaseous signal molecule, hydrogen sulfide (H2S) has been extensively employed to resist stress and control pathogens. Nevertheless, whether H2S can prevent tobacco bacterial wilt is unknown yet. We evaluated the impacts of the H2S donor sodium hydrosulfide (NaHS) on the antibacterial activity, morphology, biofilm, and transcriptome of R. solanacearum to understand the effect and mechanism of NaHS on tobacco bacterial wilt. In vitro, NaHS significantly inhibited the growth of Ralstonia solanacearum and obviously altered its cell morphology. Additionally, NaHS significantly inhibited the biofilm formation and swarming motility of R. solanacearum, and reduced the population of R. solanacearum invading tobacco roots. In field experiments, the application of NaHS dramatically decreased the disease incidence and index of tobacco bacterial wilt, with a control efficiency of up to 89.49%. The application of NaHS also influenced the diversity and structure of the soil microbial community. Furthermore, NaHS markedly increased the relative abundances of beneficial microorganisms, which helps prevent tobacco bacterial wilt. These findings highlight NaHS's potential and efficacy as a powerful antibacterial agent for preventing tobacco bacterial wilt caused by R. solanacearum.

Hydrogen Sulfide Downregulates Oncostatin M Expression via PI3K/Akt/NF-κB Signaling Processes in Neutrophil-like Differentiated HL-60 Cells

The cytokine oncostatin M (OSM) is regarded as a critical mediator in various inflammatory responses. While the gaseous signaling molecule hydrogen sulfide (H2S) plays a role in a variety of pathophysiological conditions, such as hypertension, inflammatory pain, osteoarthritis, ischemic stroke, oxidative stress, retinal degeneration, and inflammatory responses, the underlying mechanism of H2S action on OSM expression in neutrophils needs to be clarified. In this work, we studied how H2S reduces OSM expression in neutrophil-like differentiated (d)HL-60 cells. To evaluate the effects of H2S, sodium hydrosulfide (NaHS, a donor that produces H2S), ELISA, real-time PCR (qPCR), immunoblotting, and immunofluorescence staining were utilized. Although exposure to granulocyte-macrophage colony-stimulating factor (GM-CSF) resulted in upregulated levels of production and mRNA expression of OSM, these upregulated levels were reduced by pretreatment with NaHS in dHL-60 cells. Similarly, the same pretreatment lowered phosphorylated levels of phosphatidylinositol 3-kinase, Akt, and nuclear factor-kB that had been elevated by stimulation with GM-CSF. Overall, our results indicated that H2S could be a therapeutic agent for inflammatory disorders via suppression of OSM.

Exogenous hydrogen sulfide and methylglyoxal alleviate cadmium-induced oxidative stress in Salix matsudana Koidz by regulating glutathione metabolism

BackgroundCadmium (Cd) is a highly toxic element for plant growth. In plants, hydrogen sulfide (H2S) and methylglyoxal (MG) have emerged as vital signaling molecules that regulate plant growth processes under Cd stress. However, the effects of sodium hydrosulfide (NaHS, a donor of H2S) and MG on Cd uptake, physiological responses, and gene expression patterns of Salix to Cd toxicity have been poorly understood. Here, Salix matsudana Koidz. seedlings were planted in plastic pot with applications of MG (108 mg kg− 1) and NaHS (50 mg kg− 1) under Cd (150 mg kg− 1) stress.ResultsCd treatment significantly increased the reactive oxygen species (ROS) levels and malondialdehyde (MDA) content, but decreased the growth parameters in S. matsudana. However, NaHS and MG supplementation significantly decreased Cd concentration, ROS levels, and MDA content, and finally enhanced the growth parameters. Cd stress accelerated the activities of antioxidative enzymes and the relative expression levels of stress-related genes, which were further improved by NaHS and MG supplementation. However, the activities of monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) were sharply decreased under Cd stress. Conversely, NaHS and MG applications restored the MDHAR and DHAR activities compared with Cd-treated seedlings. Furthermore, Cd stress decreased the ratios of GSH/GSSG and AsA/DHA but considerably increased the H2S and MG levels and glyoxalase I-II system in S. matsudana, while the applications of MG and NaHS restored the redox status of AsA and GSH and further improved glyoxalase II activity. In addition, compared with AsA, GSH showed a more sensitive response to exogenous applications of MG and NaHS and plays more important role in the detoxification of Cd.ConclusionsThe present study illustrated the crucial roles of H2S and MG in reducing ROS-mediated oxidative damage to S. matsudana and revealed the vital role of GSH metabolism in regulating Cd-induced stress.