Hydrogen Sulfide Improves the Cold Stress Resistance through the CsARF5-CsDREB3 Module in Cucumber

As an important gas signaling molecule, hydrogen sulfide (H2S) plays a crucial role in regulating cold tolerance. H2S cooperates with phytohormones such as abscisic acid, ethylene, and salicylic acid to regulate the plant stress response. However, the synergistic regulation of H2S and auxin in the plant response to cold stress has not been reported. This study showed that sodium hydrosulfide (NaHS, an H2S donor) treatment enhanced the cold stress tolerance of cucumber seedlings and increased the level of auxin. CsARF5, a cucumber auxin response factor (ARF) gene, was isolated, and its role in regulating H2S-mediated cold stress tolerance was described. Transgenic cucumber leaves overexpressing CsARF5 were obtained. Physiological analysis indicated that overexpression of CsARF5 enhanced the cold stress tolerance of cucumber and the regulation of the cold stress response by CsARF5 depends on H2S. In addition, molecular assays showed that CsARF5 modulated cold stress response by directly activating the expression of the dehydration-responsive element-binding (DREB)/C-repeat binding factor (CBF) gene CsDREB3, which was identified as a positive regulator of cold stress. Taken together, the above results suggest that CsARF5 plays an important role in H2S-mediated cold stress in cucumber. These results shed light on the molecular mechanism by which H2S regulates cold stress response by mediating auxin signaling; this will provide insights for further studies on the molecular mechanism by which H2S regulates cold stress. The aim of this study was to explore the molecular mechanism of H2S regulating cold tolerance of cucumber seedlings and provide a theoretical basis for the further study of cucumber cultivation and environmental adaptability technology in winter.

Hemorheological parameters in individuals with different levels of oxygen body supply: the effect of nitric oxide and hydrogen sulfi de on erythrocyte microrheological characteristics.

Введение. Доставка кислорода в ткани определяется величиной объемного кровотока; он, в свою очередь, зависит от сосудистых и реологических факторов. Снижение вязкости крови (ВК) может способствовать приросту объемного кровотока и повышению эффективности доставки кислорода. Поскольку ВК тесно связана с микрореологическими свойствами эритроцитов, то можно полагать, что их положительные изменения будут способствовать улучшению кислородтранспортной функции крови. Цель исследования: сравнительный анализ гемореологических профилей у лиц с разным уровнем обеспечения организма кислородом и определение роли оксида азота (NO) и сульфида водорода (H2S) в изменениях микрореологических характеристик эритроцитов. Материалы и методы. На основе результатов определения максимального потребления кислорода (МПК) были сформированы 2 группы, в каждой из которых было по 24 практически здоровых мужчины-добровольца в возрасте от 20 до 35 лет: группа 1 – лица с умеренным обеспечением организма кислородом (МПК = 40–50 мл/кг/мин) и группа 2 – лица с относительно высоким его уровнем (МПК = 51–65 мл/кг/мин). Регистрировали параметры гемореологического профиля, напряжение кислорода в коже предплечья (tсрО2), метаболизм оксида азота (по соотношению нитраты/нитриты, NOx). Для исследования влияния газотрансмиттеров (ГТ) на микрореологию эритроцитов их инкубировали с донором NO (нитропруссидом натрия, 100 мкмоль) и донором H2S (гидросульфидом натрия, 100 мкмоль) с последующей регистрацией деформируемости и агрегации эритроцитов. Результаты. У лиц с относительно высоким обеспечением тканей кислородом отмечалась сниженная вязкость крови, ее высокий кислородтранспортный потенциал, эффективная микрореология эритроцитов и их более высокая чувствительность к ГТ при положительном влиянии последних на агрегацию и деформируемость эритроцитов. Заключение. Данные, полученные на моделях микрореологических ответов эритроцитов на доноры двух газотрансмиттеров, позволяют заключить, что, во-первых, эти ГТ, как сигнальные молекулы, положительно влияют на микрореологические характеристики эритроцитов и, следовательно, на их транспортный потенциал, и, во-вторых, эритроциты лиц, имеющих высокий уровень обеспечения организма кислородом, более чувствительны к регуляторному действию газотрансмиттеров, поскольку их микрореологические ответы на доноры были статистически значимо более выраженными. Background. Oxygen delivery to tissues is determined by the volume of blood flow that, in turn, depends on vascular and rheological factors. Blood viscosity (BV) decreasing can promote an increasing of volumetric blood flow and provide more efficient oxygen transport. Since BV depends on the erythrocyte microrheological properties it can be assumed that their positive changes will contribute to better oxygen transport. Objectives: to investigate hemorheological profiles in individuals with different levels of body oxygen supply and the role of nitrogen oxide (NO) and hydrogen sulfide (H2S) in changes of the erythrocyte microrheological characteristics. Patients/Methods. Based on the determination of maximum oxygen consumption (VO2max), 2 groups were formed, each of which consisted of 24 practically healthy male volunteers aged 20–35 years: group 1 – persons with moderate body oxygen supply (VO2max = 40–50 ml/kg/min) and group 2 – persons with a relatively high body oxygen supply (VO2max = 51–65 ml/kg/min). Hemorheological profi le parameters, oxygen tension in the forearm skin (tcpO2), and nitric oxide metabolism by the ratio of nitrates/nitrites (NOx) were recorded. To study the effect of gasotransmitters (GTs) on erythrocyte microrheology, they were incubated with NO donor (sodium nitroprusside, 100 μmol) and H2S donor (sodium hydrosulfide, 100 μmol), and erythrocytes deformability and aggregation were registered. Results. Individuals with a relatively high oxygen supply of tissues showed a reduced blood viscosity, high blood oxygen transport potential, an effective microrheology of erythrocytes and their higher sensitivity to GTs with their positive effect on erythrocytes aggregation and deformability. Conclusions. The obtained data on models of erythrocyte microrheological responses to donors of two gasotransmitters allow us to conclude that, firstly, these GTs, as signaling molecules, have a positive effect on the erythrocyte microrheological characteristics and, consequently, on their transport potential, and, secondly, erythrocytes from individuals with a high level of oxygen body supply are more sensitive to the regulatory action of GTs, because their microrheological responses to donors were statistically significantly more expressed.

Experimental Study of the Effect of Serum Hydrogen Sulfide on the Course of the Inflammatory Process in the Vaginal Wall

Introduction: Various pathological conditions are characterized by the influence of hydrogen sulfide level on the course of the pathological process. This study examines the effect of serum hydrogen sulfide levels on the inflammatory process in the vaginal wall of rats. Aims: To evaluate the effect of excess and deficiency of serum hydrogen sulfide on the course of the inflammatory process in the vaginal wall of rats. Methodology: The study was performed on 125 female Wistar rats under 1 year of age and weighing 160.0 to 200.0 grams. All animals were divided into 7 groups: control (intact rats) and 6 experimental groups with different H2S levels and different treatment approaches of inflammation in the vaginal wall. The level of serum hydrogen sulfide was studied and the levels of TNF-α and IL-1β in the tissue homogenate of the vaginal wall were determined. In all experimental groups, the study was performed in dynamics - 10 min, 4, 8 and 24h after simulation of inflammation. Results: The dynamics of local levels of TNF-α and IL-1β in all groups had a similar trend and was characterized by the rapid development of the inflammatory process from its simulation to 4 hours of study, followed by gradual attenuation of inflammation and almost complete normalization of the studied indicators for 24 hours. Preliminary serial introduction of sodium hydrosulfide, as a donor of hydrogen sulfide, allowed to reduce the degree of manifestation of the inflammatory process and to achieve faster normalization of the studied parameters. At the same time, the artificially created deficiency of serum hydrogen sulfide (previous serial administration of propargylglycine) prolonged the duration and increased the studied indicators of inflammation in the vaginal wall. Conclusions: The course and intensity of the inflammatory process in the vaginal wall of rats are directly dependent on the background level of serum hydrogen sulfide.

H2O2 Functions as a Downstream Signal of IAA to Mediate H2S-Induced Chilling Tolerance in Cucumber

Hydrogen sulfide (H2S) plays a crucial role in regulating chilling tolerance. However, the role of hydrogen peroxide (H2O2) and auxin in H2S-induced signal transduction in the chilling stress response of plants was unclear. In this study, 1.0 mM exogenous H2O2 and 75 μM indole-3-acetic acid (IAA) significantly improved the chilling tolerance of cucumber seedlings, as demonstrated by the mild plant chilling injury symptoms, lower chilling injury index (CI), electrolyte leakage (EL), and malondialdehyde content (MDA) as well as higher levels of photosynthesis and cold-responsive genes under chilling stress. IAA-induced chilling tolerance was weakened by N, N′-dimethylthiourea (DMTU, a scavenger of H2O2), but the polar transport inhibitor of IAA (1-naphthylphthalamic acid, NPA) did not affect H2O2-induced mitigation of chilling stress. IAA significantly enhanced endogenous H2O2 synthesis, but H2O2 had minimal effects on endogenous IAA content in cucumber seedlings. In addition, the H2O2 scavenger DMTU, inhibitor of H2O2 synthesis (diphenyleneiodonium chloride, DPI), and IAA polar transport inhibitor NPA reduced H2S-induced chilling tolerance. Sodium hydrosulfide (NaHS) increased H2O2 and IAA levels, flavin monooxygenase (FMO) activity, and respiratory burst oxidase homolog (RBOH1) and FMO-like protein (YUCCA2) mRNA levels in cucumber seedlings. DMTU, DPI, and NPA diminished NaHS-induced H2O2 production, but DMTU and DPI did not affect IAA levels induced by NaHS during chilling stress. Taken together, the present data indicate that H2O2 as a downstream signal of IAA mediates H2S-induced chilling tolerance in cucumber seedlings.

Necroptosis Inhibition by Hydrogen Sulfide Alleviated Hypoxia-Induced Cardiac Fibroblasts Proliferation via Sirtuin 3

Myocardial ischemia or hypoxia can induce myocardial fibroblast proliferation and myocardial fibrosis. Hydrogen sulfide (H2S) is a gasotransmitter with multiple physiological functions. In our present study, primary cardiac fibroblasts were incubated with H2S donor sodium hydrosulfide (NaHS, 50 μM) for 4 h followed by hypoxia stimulation (containing 5% CO2 and 1% O2) for 4 h. Then, the preventive effects on cardiac fibroblast proliferation and the possible mechanisms were investigated. Our results showed that NaHS reduced the cardiac fibroblast number, decreased the hydroxyproline content; inhibited the EdU positive ratio; and down-regulated the expressions of α-smooth muscle actin (α-SMA), the antigen identified by monoclonal antibody Ki67 (Ki67), proliferating cell nuclear antigen (PCNA), collagen I, and collagen III, suggesting that hypoxia-induced cardiac fibroblasts proliferation was suppressed by NaHS. NaHS improved the mitochondrial membrane potential and attenuated oxidative stress, and inhibited dynamin-related protein 1 (DRP1), but enhanced optic atrophy protein 1 (OPA1) expression. NaHS down-regulated receptor interacting protein kinase 1 (RIPK1) and RIPK3 expression, suggesting that necroptosis was alleviated. NaHS increased the sirtuin 3 (SIRT3) expressions in hypoxia-induced cardiac fibroblasts. Moreover, after SIRT3 siRNA transfection, the inhibitory effects on cardiac fibroblast proliferation, oxidative stress, and necroptosis were weakened. In summary, necroptosis inhibition by exogenous H2S alleviated hypoxia-induced cardiac fibroblast proliferation via SIRT3.

Hydrogen sulfide prevents arterial medial calcification in rats with diabetic nephropathy

Background Arterial medial calcification (AMC) is associated with a high incidence of cardiovascular risk in patients with type 2 diabetes and chronic kidney disease. Here, we tested whether hydrogen sulfide (H2S) can prevent AMC in rats with diabetic nephropathy (DN). Methods DN was induced by a single injection of streptozotocin and high-fat diet (45% kcal as fat) containing 0.75% adenine in Sprague–Dawley rats for 8 weeks. Results Rats with DN displayed obvious calcification in aorta, and this was significantly alleviated by Sodium Hydrosulfide (NaHS, a H2S donor, 50 μmol/kg/day for 8 weeks) treatment through decreasing calcium and phosphorus content, ALP activity and calcium deposition in aorta. Interestingly, the main endogenous H2S generating enzyme activity and protein expression of cystathionine-γ-lyase (CSE) were largely reduced in the arterial wall of DN rats. Exogenous NaHS treatment restored CSE activity and its expression, inhibited aortic osteogenic transformation by upregulating phenotypic markers of smooth muscle cells SMα-actin and SM22α, and downregulating core binding factor α-1 (Cbfα-1, a key factor for bone formation), protein expressions in rats with DN when compared to the control group. NaHS administration also significantly reduced Stat3 activation, cathepsin S (CAS) activity and TGF-β1 protein level, and improved aortic elastin expression. Conclusions H2S may have a clinical significance for treating AMC in people with DN by reducing Stat3 activation, CAS activity, TGF-β1 level and increasing local elastin level.

Features of ozone effect on oxygen-dependent processes in the blood under hypoxic conditions

Introduction. Ozone is a physiological factor that can change hemoglobin oxygen affinity and the formation of gaseous transmitters (NO, H2S). The aim is to study the effect of ozone with gaseous transmitters donors on oxygen-dependent processes in the blood under hypoxic conditions in vitro. Materials and methods. Blood samples were divided into 6 groups of 3 ml each. Groups 2, 4, 5, 6 were pretreated with a deoxygenating gas mixture (5.5 % CO2; 94.5 % N2). In groups 3, 4, 5, 6, ozonized isotonic sodium chloride solution (with an ozone concentration of 6 mg/l) was added, and in groups 5 and 6, the donors of gas transmitters nitroglycerin and sodium hydrosulfide, respectively, were additionally introduced. Results. Pre-deoxygenation reduces the effect of ozone on oxygen transport in the blood. Nitroglycerin prevents this effect. The action of ozone under hypoxic conditions leads to an increase of content of NO3-/NO2- and H2S, and combination with nitroglycerin and sodium hydrosulfide increase these parameters. Deoxygenation due to ozone reduces parameters of lipid peroxidation (malonic dialdehyde, diene conjugates), retinol and α-tocopherol, and the same result in the nitroglycerin group. Conclusion. Under hypoxic conditions, a decrease in the effect of ozone on oxygen-dependent processes is reported. Nitroglycerin reduces its manifestation, while sodium hydrosulfide does not have a similar effect.

Hydrogen sulfide improves the cold stress resistance through the CsARF5-CsDREB3 module in cucumber

Hydrogen sulfide (H2S) plays a crucial role in regulating cold tolerance. But the synergistic regulation of H2S and auxin in the plant response to cold stress has not been reported. In the study, we found that sodium hydrosulfide (NaHS, an H2S donor) treatment enhanced the cold tolerance of cucumber seedlings and increased the level of auxin. CsARF5, a cucumber auxin response factor (ARF) gene was isolated and its role in regulating H2S-mediated cold stress tolerance was described. Transgenic cucumber leaves overexpressing CsARF5 were obtained. Physiological analysis indicated that overexpression of CsARF5 enhanced the cold stress tolerance of cucumber and the regulation of the cold stress response by CsARF5 depends on H2S. In addition, molecular assays showed that CsARF5 modulated cold stress response by directly activating the expression of the dehydration-responsive element-binding (DREB)/C-repeat binding factor (CBF) gene CsDREB3, which was identified as a positive regulator of cold stress. Taken together, our results suggest that CsARF5 plays an important role in H2S-mediated cold stress in cucumber. These results shed light on the molecular mechanism by which H2S regulates cold stress response by mediating auxin signaling, and will provide insights for further studies on the molecular mechanism by which H2S regulates cold stress.HighlightAuxin signaling participates in H2S-mediated cold stress through the CsARF5-CsDREB3 module in cucumber.