Search Results (81)

This study aims to investigate the mechanism by which the total flavones of Rhododendron (TFR) protect against cerebral ischemic injury through the endothelial-derived H₂S-mediated regulation of RhoA phosphorylation at the Ser188 and Rho kinase 2 (ROCK₂) phosphorylation at Thr436. For experimental design, mouse or rat cerebrovascular endothelial cells (ECs) were cultured with or without neurons and subjected to hypoxia/reoxygenation (H/R) injury. The vasodilation of the cerebral basilar artery was assessed. Cerebral ischemia/reperfusion (I/R) injury was induced in mice by bilateral carotid artery ligation, followed by Morris water maze and open field behavioral assessments. The protein levels of cystathionine-γ-lyase (CSE), 3-mercaptopyruvate sulfurtransferase (3-MST), RhoA, ROCK₂, p-RhoA (RhoA phosphorylated at Ser188), and p-ROCK₂ (ROCK₂ phosphorylated at Thr436) were quantified. Additionally, the activities of RhoA and ROCK₂ were measured. Notably, TFR significantly inhibited H/R-induced H₂S reduction and suppressed the increased expression and activity of RhoA and ROCK₂ in ECs, effects attenuated by CSE or 3-MST knockout. Moreover, TFR-mediated cerebrovascular dilation was reduced by RhoA or ROCK₂ inhibitors, while the protective effect of TFR against cerebral I/R injury in mice was markedly attenuated by the heterozygous knockout of ROCK₂. In the ECs-co-cultured neurons, the inhibition of TFR on H/R-induced neuronal injury and decrease in H₂S level in the co-culture was attenuated by the knockout of CSE or 3-MST in the ECs. TFR notably inhibited the H/R-induced upregulation of neuronal RhoA, ROCK₂, and p-ROCK₂ protein levels, as well as the activities of RhoA and ROCK₂, while reversing the decrease in p-RhoA. However, the knockout of CSE or 3-MST in the ECs significantly attenuated the inhibition of TFR on these increases. Furthermore, 3-MST knockout in ECs attenuated the TFR-mediated suppression of p-RhoA reduction. Additionally, CSE or 3-MST knockout in ECs exacerbated H/R-induced neuronal injury, reduced H₂S level in the co-culture system, and increased RhoA activity and ROCK₂ expression in neurons. In summary, TFR protected against ischemic cerebral injury by endothelial-derived H₂S promoting the phosphorylation of RhoA at Ser188 but inhibited the phosphorylation of ROCK₂ at Thr436 to inhibit the RhoA-ROCK₂ pathway in neurons. Full article

Here, we describe the effects of double knockout (KO) of the cbs and cse genes, which are responsible for H₂S synthesis through the transsulfuration pathway, and KO of the sulfurtransferase gene (dtst1) in Drosophila melanogaster females. The analysis of H₂S production in flies showed minimal levels in the double- and triple-knockout strains. The double- (cbs-/-; cse-/-) and triple- (cbs-/-; cse-/-; dtst-/-) KO flies exhibited a shortened lifespan and reduced fecundity, and showed dramatic changes in Malpighian tubule morphology. The transcriptomic analysis revealed a profound increase in the expression levels of several genes involved in excretory system function in the double-KO and especially the triple-KO flies. Importantly, major groups of differentially expressed genes (DEGs) in the whole bodies of females and ovaries of KO strains included genes responsible for detoxification, reproduction, mitochondrial activity, excretion, cell migration, and muscle system function. The reduced fecundity observed in the double- and triple-KO flies correlated with pronounced changes in the ovarian transcriptome. At the same time, the single knockout of dtst1 increased the flies’ fecundity and lifespan. Our experiments exploring unique Drosophila strains with KO of major H₂S-related genes revealed several new pathways controlled by this ancient adaptogenic system that is involved in various human diseases and aging. Full article

Sleep disorders increase the risk of cardiovascular diseases. However, the underlying mechanisms remain unclear. This study aims to examine the critical role of oxytocin neurons in the paraventricular nucleus (PVN^OXT) in regulating the cardiovascular system and to elucidate potential mechanisms through which sleep disturbance may contribute to cardiovascular diseases. In this study, using an automated sleep deprivation system, mice were given chronic sleep deprivation (cSD) for 7 days, 6 h per day. cSD induced blood transcriptomic alterations accompanied by lower heart rate, higher blood pressure, and elevated cardiac autophagy/apoptosis. Instant optogenetic activation of oxytocin neurons in the paraventricular nucleus (PVN^OXT) provoked heart rate suppression in normal mice, whereas in cSD mice, activation precipitated intermittent cardiac arrest. On the contrary, inhibition of PVN^OXT showed no influence on the cardiovascular system of normal mice, but it attenuated cSD-induced rise in blood pressure. Long-term low-frequency stimulation (LTF) of PVN^OXT decreased neuronal excitability and oxytocin release, effectively reversing cSD-mediated cardiovascular responses. Mechanistically, cSD triggered the upregulation of blood-derived 3-mercaptopyruvate sulfurtransferase (mPST), and a suppression of PVN^OXT postsynaptic activity to a certain extent. The quick and long-term decrease of oxytocin by LTF could lead to feedback inhibition in mPST expression and thus reverse cSD-mediated cardiovascular responses. Altogether, modulation of PVN^OXT could mediate cSD-induced cardiovascular abnormalities without affecting normal mice. Our research provided potential targets and key mechanisms for cardiovascular diseases associated with sleep disorders. Full article

Background/Objectives: Hydrogen sulfide (H₂S) is a vasorelaxant gas and exerts anti-oxidative, anti-inflammatory, and cytoprotective effects. H₂S has been implicated in regulating placental vaso-activity and angiogenesis. It is believed that abnormal trophoblast production of vasodilators and angiogenic factors contributes to pre-eclampsia development. However, little is known about whether aberrant H₂S production is present in placental trophoblasts from pre-eclamptic pregnancies. Methods: Trophoblasts were isolated from normal and pre-eclamptic placentas. After incubation, cell production of H₂S in the culture medium and the cellular levels of H₂S were analyzed by reversed phase high-performance liquid chromatography (RP-HPLC). Expression levels of the three key H₂S converting enzymes, cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), were determined by immunohistochemistry. The protein expression of CBS and CSE was assessed by Western blot analysis. Results: (1) Trophoblast production and cellular levels of H₂S were significantly reduced in cells from pre-eclamptic vs. normal placentas; (2) free H₂S production was increased in a time-dependent manner in cultured trophoblasts from normal, but not from pre-eclamptic, placentas; and (3) strong CBS and CSE expression was seen in trophoblasts from normal, as opposed to pre-eclamptic, placentas. Reduced CBS and CSE expression in trophoblasts from pre-eclamptic vs. normal placentas were confirmed by Western blot analysis; and (4) 3-MST expression was undetachable in both normal and pre-eclamptic placentas, but 3-MST expression was strongly expressed in the first and second trimester placentas. Conclusions: These data provide plausible evidence that downregulation of CBS and CSE, but not 3-MST, expression may be responsible for reduced free H₂S production and decreased cellular H₂S levels in pre-eclamptic placentas. Our data provide further evidence that expression of 3-MST in placental trophoblasts is likely gestational age (developmental)-dependent. Full article

Both hydrogen sulfide and endocannabinoids can protect the neural retina from toxic insults under in vitro and in vivo conditions. Purpose: The aim of the present study was two-fold: (a) to examine the neuroprotective action of cannabinoids [methanandamide and 2-arachidonyl glycerol (2-AG)] against hydrogen peroxide (H₂O₂)-induced oxidative damage in the isolated bovine retina and (b) to evaluate the role of endogenously biosynthesized hydrogen sulfide (H₂S) in the inhibitory actions of cannabinoids on the oxidative stress in the bovine retina. Methods: Isolated neural retinas from cows were exposed to oxidative damage using H₂O₂ (100 µM) for 10 min. When used, tissues were pretreated with methanandamide (1 nM–100 nM) and 2-AG (1–10 µM) for 30 min before a 10 min treatment with H₂O₂ (100 µM). In some experiments, retinas were pretreated with inhibitors of the biosynthesis of H₂S [cystathionine β-synthase/cystathionine γ-lyase (CBS/CSE), aminooxyacetic acid, AOAA 30 µM, or 3-mercaptopyruvate sulfurtransferase (3MST), α-keto-butyric acid, KBA 1 mM] and the CB1-receptor antagonist, AM251 (100 nM) for 30 min before treatment with methanandamide (1 nM–100 µM). Enzyme immunoassay measurement of 8-epi PGF2α (8-isoprostane) levels was performed to assess lipid peroxidation in retinal tissues. Results: In the presence of H₂O₂ (100 µM), methanandamide (1 nM–100 µM) and 2-AG (1–10 µM) significantly (p < 0.001) blocked the H₂O₂-induced elevation in 8-isoprostane levels in the isolated bovine retina. In the presence of the CB1 antagonist AM251 (100 nM), the effect of methanandamide (1 nM) on the H₂O₂-induced 8-isoprostane production was significantly (p < 0.001) attenuated. While AOAA (30 µM) had no significant (p > 0.05) effect on the inhibition of H₂O₂-induced oxidative stress elicited by methanandamide, KBA (1 mM) reversed the neuroprotective action of methanandamide. Conclusions: The cannabinoids, methanandamide and 2-AG can prevent H₂O₂-induced oxidative stress in the isolated bovine retina. The neuroprotective actions of cannabinoids are partially dependent upon the activation of the CB1 receptors and endogenous production of H₂S via the 3-MST/CAT pathway. Full article

The oxidative modification of specific cysteine residues to persulfides is thought to be the main way by which hydrogen sulfide (H₂S) exerts its biological and signaling functions. Therefore, protein persulfidation represents an important thiol-switching mechanism as other reversible redox post-translational modifications. Considering their reductase activity but also their connections with proteins that generate H₂S and its related molecules, the glutaredoxin (GRX) and thioredoxin (TRX)-reducing systems have potential dual roles in both protein persulfidation and depersulfidation. In this review, we will first focus on recent advances describing the physiological pathways leading to protein persulfidation before discussing the dual roles of the physiological TRX and glutathione/GRX-reducing systems in protein persulfidation/depersulfidation. Full article

Down syndrome (DS) is a multisystemic disorder that includes accelerated aging caused by trisomy 21. In particular, overexpression of cystathionine-β-synthase (CBS) is linked to excess intracellular hydrogen sulfide (H₂S), a mitochondrial toxin at higher concentrations, which impairs cellular viability. Concurrent overexpression of superoxide dismutase 1 (SOD1) may increase oxidative stress by generating excess hydrogen peroxide (H₂O₂) while also mitigating the toxic H₂S burden via a non-canonical sulfide-oxidizing mechanism. We investigated the phenotypic variability in basal H₂S levels in relation to DS B lymphocyte cell health and SOD1 in H₂S detoxification. The H₂S levels were negatively correlated with the DS B lymphocyte growth rates but not with CBS protein. Pharmacological inhibition of SOD1 using LCS-1 significantly increased the H₂S levels to a greater extent in DS cells while also decreasing the polysulfide products of H₂S oxidation. However, DS cells exhibited elevated H₂O₂ and lipid peroxidation, representing potential toxic consequences of SOD1 overexpression. Treatment of DS cells with a pleiotropic carbon nanozyme (pleozymes) decreased the total oxidative stress and reduced the levels of the H₂S-generating enzymes CBS and 3-mercaptopyruvate sulfurtransferase (MPST). Our results indicate that pleozymes may bridge the protective and deleterious effects of DS SOD1 overexpression on H₂S metabolism and oxidative stress, respectively, with cytoprotective benefits. Full article

Background: Collectively, leishmaniasis and Chagas disease cause approximately 8 million cases and more than 40,000 deaths annually, mostly in tropical and subtropical regions. The current drugs used to treat these diseases have limitations and many undesirable side effects; hence, new drugs with better clinical profiles are needed. Fungal endophytes associated with plants are known to produce a wide array of bioactive secondary metabolites, including antiprotozoal compounds. In this study, we analyzed endophytic fungal isolates associated with Theobroma cacao and Coffea arabica crop plants, which yielded extracts with antitrypanosomatid activity. Methods: Crude extracts were subjected to bioassay-guided isolation by HPLC, followed by spectrometric and spectroscopic analyses via mass spectrometry (MS) and nuclear magnetic resonance (NMR), Results: Compounds 1–9 were isolated and displayed novel antitrypanosomal and antileishmanial activities ranging from 0.92 to 32 μM. Tandem liquid chromatography–mass spectrometry (LC–MS) analysis of the organic extracts from different strains via the feature-based Global Natural Products Social (GNPS) molecular networking platform allowed us to dereplicate a series of metabolites (10–23) in the extracts. Molecular docking simulations of the active compounds, using the 3-mercaptopyruvate sulfurtransferase protein from L. donovani (Ld3MST) and the cruzipain enzyme from T. cruzi as putative molecular targets, allowed us to suggest possible mechanisms for the action of these compounds. Conclusions: The isolation of these antiprotozoal compounds confirms that crop plants like coffee and cacao harbor populations of endophytes with biomedical potential that confer added value to these crops. Full article

Background: We have evidence that hydrogen sulfide (H₂S)-releasing compounds can reduce intraocular pressure in normotensive and glaucomatous rabbits by increasing the aqueous humor (AH) outflow through the trabecular meshwork. Since H₂S has been reported to possess neuroprotective actions, the prevention of retinal ganglion cell loss is an important strategy in the pharmacotherapy of glaucoma. Consequently, the present study aimed to investigate the neuroprotective actions of H₂S-releasing compounds against hydrogen peroxide (H₂O₂)-induced oxidative stress in an isolated bovine retina. Materials and Methods: The isolated neural retinae were pretreated with a substrate for H₂S biosynthesis called L-cysteine, with the fast H₂S-releasing compound sodium hydrosulfide, and with a mitochondrial-targeting H₂S-releasing compound, AP123, for thirty minutes before a 30-min oxidative insult with H₂O₂ (100 µM). Lipid peroxidation was assessed via an enzyme immunoassay by measuring the stable oxidative stress marker, 8-epi PGF2α (8-isoprostane), levels in the retinal tissues. To determine the role of endogenous H₂S, studies were performed using the following biosynthesis enzyme inhibitors: aminooxyacetic acid (AOAA, 30 µM); a cystathione-β-synthase/cystathionine-γ-lyase (CBS/CSE) inhibitor, α–ketobutyric acid (KBA, 1 mM); and a 3-mercaptopyruvate-s-sulfurtransferase (3-MST) inhibitor, in the absence and presence of H₂S-releasing compounds. Results: Exposure of the isolated retinas to H₂O₂ produced a time-dependent (10–40 min) and concentration-dependent (30–300 µM) increase in the 8-isoprostane levels when compared to the untreated tissues. L-cysteine (10 nM–1 µM) and NaHS (30 –100 µM) significantly (p < 0.001; n = 12) prevented H₂O₂-induced oxidative damage in a concentration-dependent manner. Furthermore, AP123 (100 nM–1 µM) attenuated oxidative H₂O₂ damage resulted in an approximated 60% reduction in 8-isoprostane levels compared to the tissues treated with H₂O₂ alone. While AOAA (30 µM) and KBA (1 mM) did not affect the L-cysteine evoked attenuation of H₂O₂-induced oxidative stress, KBA reversed the antioxidant responses caused by AP123. Conclusions: In conclusion, various forms of H₂S-releasing compounds and the substrate, L-cysteine, can prevent H₂O₂-induced lipid peroxidation in an isolated bovine retina. Full article

Background: Hydrogen sulfide (H₂S)-releasing compounds can reduce intraocular pressure in normotensive rabbits by increasing aqueous humor (AH) outflow through the trabecular meshwork. In the present study, we investigated the contribution of endogenous H₂S and the role of intramurally generated prostaglandins in the observed increase in AH outflow facility in an ex vivo porcine ocular anterior segment model. Material and Methods: Porcine ocular anterior segment explants were perfused with Dulbecco’s Modified Eagle’s Medium maintained at 37 °C and gassed with 5% CO₂ and 95% air under an elevated pressure of 15 mmHg for four hours. Perfusates from the anterior segment explants were collected and immediately assayed for their H₂S and prostaglandin E₂ content. Results: Elevating perfusion pressure from 7.35 to 15 mm Hg significantly (p < 0.001) increased H₂S concentration in the perfusate from 0.4 ± 0.1 to 67.6 ± 3.6 nM/µg protein. In the presence of an inhibitor of cystathionine ß-synthase/cystathionine γ-lyase, aminooxyacetic acid (AOAA, 30 µM), or an inhibitor of 3-mercaptopyruvate sulfurtransferase, α-ketobutyric acid (KBA, 1 mM), the effects of elevated pressure on H₂S levels in the perfusate was significant (p < 0.001). Furthermore, flurbiprofen (30 µM) and indomethacin (10 µM) attenuated the elevated pressure-induced increase in H₂S levels in the perfusate. Interestingly, elevating perfusion pressure had no significant effect on PGE₂ concentrations in the perfusate. While the inhibition of H₂S biosynthesis by AOAA or KBA did not affect PGE₂ levels in perfusate, flurbiprofen (30 µM) caused a significant (p < 0.05) decrease in the concentration of PGE₂ under conditions of elevated perfusion pressure. Conclusions: We conclude that the elevated perfusion pressure-induced increase in H₂S concentrations depends upon the endogenous biosynthesis of H₂S and intramurally produced prostaglandins in the porcine anterior segment explants. While the concentration of PGE₂ in the perfusate under elevated perfusion pressure was unaffected by pretreatment with inhibitors of H₂S biosynthesis, it was reduced in the presence of an inhibitor of cyclooxygenase. Full article

Pregnant women with chronic kidney disease (CKD) face increased risks of adverse outcomes in their adult offspring. Offspring rats born to dams fed an adenine diet develop hypertension, coinciding with dysregulated hydrogen sulfide (H₂S) and nitric oxide (NO) pathways, as well as alterations in gut microbiota. Chondroitin sulfate (CS) is a multifunctional food known for its diverse bioactivities. As a sulfate prebiotic, CS has shown therapeutic potential in various diseases. Here, we investigated the protective effects of maternal CS supplementation against hypertension in offspring induced by an adenine diet. Mother rats were administered regular chow, 0.5% adenine, 3% CS, or a combination throughout gestation and lactation. Maternal CS supplementation effectively protected offspring from hypertension induced by the adenine diet. These beneficial effects of CS were connected with increased renal mRNA and protein levels of 3-mercaptopyruvate sulfurtransferase, an enzyme involved in H₂S production. Furthermore, maternal CS treatment significantly enhanced alpha diversity and altered beta diversity of gut microbiota in adult offspring. Specifically, perinatal CS treatment promoted the abundance of beneficial microbes such as Roseburia hominis and Ruminococcus gauvreauii. In conclusion, perinatal CS treatment mitigates offspring hypertension associated with maternal adenine diet, suggesting that early administration of sulfate prebiotics may hold preventive potential. These findings warrant further translational research to explore their clinical implications. Full article

Leukemias are cancers of the blood-forming system, representing a significant challenge in medical science. The development of leukemia cells involves substantial disturbances within the cellular machinery, offering hope in the search for effective selective treatments that could improve the 5-year survival rate. Consequently, the pathophysiological processes within leukemia cells are the focus of critical research. Enzymes such as cystathionine beta-synthase and sulfurtransferases like thiosulfate sulfurtransferase, 3-mercaptopyruvate sulfurtransferase, and cystathionine gamma-lyase play a vital role in cellular sulfur metabolism. These enzymes are essential to maintaining cellular homeostasis, providing robust antioxidant defenses, and supporting cell division. Numerous studies have demonstrated that cancerous processes can alter the expression and activity of these enzymes, uncovering potential vulnerabilities or molecular targets for cancer therapy. Recent laboratory research has indicated that certain leukemia cell lines may exhibit significant changes in the expression patterns of these enzymes. Analysis of the scientific literature and online datasets has confirmed variations in sulfur enzyme function in specific leukemic cell lines compared to normal leukocytes. This comprehensive review collects and analyzes available information on sulfur enzymes in normal and leukemic cell lines, providing valuable insights and identifying new research pathways in this field. Full article

Dimethyl sulfoxide (DMSO), an organosulfur compound, is widely used as the gold standard solvent in biological research. It is used in cell culture experiments and as a component of formulations in in vivo studies. Unfortunately, parameters related to sulfur metabolism are often not taken into account when using DMSO. Therefore, in this work we aim to show that the addition of DMSO to the culture medium (even in amounts commonly considered acceptable) alters some parameters of sulfur metabolism. For this study, we used three cell lines: a commercially available Caco-2 line (HTB-37, ATCC) and two lines created as part of our early studies (likewise previously described in the literature) to investigate the anomalies of sulfur metabolism in mucopolysaccharidosis. As the negative effects of DMSO on the cell membrane are well known, additional experiments with the partial loading of DMSO into polymerosomes (poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide), PEG-PLGA) were performed to eliminate these potentially disruptive effects. The results show that DMSO is a source of interference in studies related to sulfur metabolism and that there are not just simple effects that can be corrected in the final result by subtracting control values, since complex synergisms are also observed. Full article

S-allyl-L-cysteine (SAC) is a sulfur compound present in fresh garlic. The reference literature describes its anticancer, antioxidant and neuroprotective effects. Breast cancer is infamously known as one of the most commonly diagnosed malignancies among women worldwide. Its morbidity and mortality make it reasonable to complete and expand knowledge on this cancer’s characteristics. Hydrogen sulfide (H₂S) and its naturally occurring donors are well-known investigation subjects for diverse therapeutic purposes. This study was conducted to investigate the SAC antiproliferative potential and effect on three enzymes involved in H₂S metabolism: 3-mercaptopyruvate sulfurtransferase (MPST), cystathionine γ-lyase (CTH), and cystathionine β-synthase (CBS). We chose the in vitro cellular model of human breast adenocarcinomas: MCF-7 and MDA-MB-231. The expression of enzymes after 2, 4, 6, 8, and 24 h incubation with 2.24 mM, 3.37 mM, and 4.50 mM SAC concentrations was examined. The number of living cells was determined by the MTS assay. Changes in cellular plasma membrane integrity were measured by the LDH test. Expression changes at the protein level were analyzed using Western blot. A significant decrease in viable cells was registered for MCF-7 cells after all incubation times upon 4.50 mM SAC exposure, and after 6 and 24 h only in MDA-MB-231 upon 4.50 mM SAC. In both cell lines, the MPST gene expression significantly increased after the 24 h incubation with 4.50 mM SAC. S-allyl-L-cysteine had opposite effects on changes in CTH and CBS expression in both cell lines. In our research model, we confirmed the antiproliferative potential of SAC and concluded that our studies provided current information about the increase in MPST gene expression mediated by S-allyl-L-cysteine in the adenocarcinoma in vitro cellular model for the MCF-7 and MDA-MB-231 cell lines. Further investigation of this in vitro model can bring useful information regarding sulfur enzyme metabolism of breast adenocarcinoma and regulating its activity and expression (gene silencing) in anticancer therapy. Full article

Hydrogen sulfide (H₂S) and polysulfides (H₂S_n, n ≥ 2) produced by enzymes play a role as signalling molecules regulating neurotransmission, vascular tone, cytoprotection, inflammation, oxygen sensing, and energy formation. H₂S_n, which have additional sulfur atoms to H₂S, and other S-sulfurated molecules such as cysteine persulfide and S-sulfurated cysteine residues of proteins, are produced by enzymes including 3-mercaptopyruvate sulfurtransferase (3MST). H₂S_n are also generated by the chemical interaction of H₂S with NO, or to a lesser extent with H₂O₂. S-sulfuration (S-sulfhydration) has been proposed as a mode of action of H₂S and H₂S_n to regulate the activity of target molecules. Recently, we found that H₂S/H₂S₂ regulate the release of neurotransmitters, such as GABA, glutamate, and D-serine, a co-agonist of N-methyl-D-aspartate (NMDA) receptors. H₂S facilitates the induction of hippocampal long-term potentiation, a synaptic model of memory formation, by enhancing the activity of NMDA receptors, while H₂S₂ achieves this by activating transient receptor potential ankyrin 1 (TRPA1) channels in astrocytes, potentially leading to the activation of nearby neurons. The recent findings show the other aspects of TRPA1 channels—that is, the regulation of the levels of sulfur-containing molecules and their metabolizing enzymes. Disturbance of the signalling by H₂S/H₂S_n has been demonstrated to be involved in various diseases, including cognitive and psychiatric diseases. The physiological and pathophysiological roles of these molecules will be discussed. Full article