Cystathionine Β-synthase Research Articles

Role of hydrogen sulfide in ventilatory responses to hypercapnia in the medullary raphe of adult rats.

What is the central question of this study? There is evidence that H2 S plays a role in the control of breathing: what are its actions on the ventilatory and thermoregulatory responses to hypercapnia via effects in the medullary raphe, a brainstem region that participates in the ventilatory adjustments to hypercapnia? What is the main finding and its importance? Hypercapnia increased the endogenous production of H2 S in the medullary raphe. Inhibition of endogenous H2 S attenuated the ventilatory response to hypercapnia in unanaesthetized rats, suggesting its excitatory action via the cystathionine β-synthase-H2 S pathway in the medullary raphe. Hydrogen sulfide (H2 S) has been recently recognized as a gasotransmitter alongside carbon monoxide (CO) and nitric oxide (NO). H2 S seems to modulate the ventilatory and thermoregulatory responses to hypoxia and hypercapnia. However, the action of the H2 S in the medullary raphe (MR) on the ventilatory responses to hypercapnia remains to be elucidated. The present study aimed to assess the role of H2 S in the MR (a brainstem region that contains CO2 -sensitive cells and participates in the ventilatory adjustments to hypercapnia) in the ventilatory responses to hypercapnia in adult unanaesthetized Wistar rats. To do so, aminooxyacetic acid (AOA; a cystathionine β-synthase (CBS) enzyme inhibitor), propargylglycine (PAG; a cystathionine γ-lyase enzyme inhibitor) and sodium sulfide (Na2 S; an H2 S donor) were microinjected into the MR. Respiratory frequency (fR ), tidal volume (VT ), ventilation ( ), oxygen consumption ( ) and body temperature (Tb ) were measured under normocapnic (room air) and hypercapnic (7% CO2 ) conditions. H2 S concentration within the MR was determined. Microinjection of the drugs did not affect fR , VT and during normocapnia when compared to the control group. However, the microinjection of AOA, but not PAG, attenuated fR and during hypercapnia in comparison to the vehicle group, but had no effects on Tb . In addition, we observed an increase in the endogenous production of H2 S in the MR during hypercapnia. Our findings indicate that endogenously produced H2 S in the MR plays an excitatory role in the ventilatory response to hypercapnia, acting through the CBS-H2 S pathway.

H2S-ВИВІЛЬНЮЮЧИЙ НЕСТЕРОЇДНИЙ ПРОТИЗАПАЛЬНИЙ ПРЕПАРАТ АТВ-340 ЗНИЖУЄ МЕЗЕНТЕРІАЛЬНОГО МЕТАЗАПАЛЕННЯ ЗА УМОВ СТАРІННЯ ТА ПОШКОДЖУВАЛЬНОГО ВПЛИВУ ВИСОКОФРУКТОЗНОЇ ДІЄТИ

Metaflammation (MF) is associated with visceral adiposities involved in the metabolic, cardiovascular, and gastrointestinal disease pathogenesis while their target therapeutic strategy is still limited. The link between mesenteric white adipocytes (MA) and stromal-vascular cellular remodeling in advanced age and Western diet consumption which is the base of MF remain undiscovered. Hydrogen Sulfide (H2S) non-steroidal anti-inflammatory drugs (H2S-NSAIDs) are a promising novel class of drugs regarding their cytoprotective, regulatory redox signaling, vasodilatory, and anti-inflammatory effects. Aim. To study the effectiveness of novel H2S-NSAIDs ATB-340, a hybrid compound of H2S and aspirin (ASA) over conventional ASA, and combination of ASA and NaHS on mesenteric cellular adaptive changes in experimental age- and high fructose dietary (HFD)-induced injury. Methods: Mesenteric subcellular adaptive responses of aged male rats on a standard diet (SD) or 4 weeks HFD that underwent acute water-immersion restraint stress (WIRS) were evaluated by electron microscopy. The effects of 9 days exogenous administration of ATB-340 (17.5 mg/kg/day), ASA (10 mg/kg/day) and sodium hydrosulfide (NaHS, 5.6 mg/kg/day) were investigated. Serum glucose level, thiobarbituric acid reactive substances (TBARS), and activities of cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS), thiosulfate-dithiol sulfurtransferase (TST), and sulfite oxidase (SO) were examined biochemically using spectrophotometry. Results: In HFD groups exposed to WIRS treatment with ATB-340 protected MA, as well their mitochondria, microvascular endothelial, and sub-endothelial structures, fibroblasts were observed vs the ASA and H2S+ASA-treated groups that had signs of endothelial dysfunction, MA damage with dysfunctional mitochondria, and mitochondria with fat incorporation. In rats fed with HFD and ASA treatment, low activities of CSE, CBS, TST and the rise of TBARS level and SO activity were observed. Treatment with ASA+NaHS, ATB-340 of aged rats lowered TBARS and enhanced H2S enzyme activities in contrast to the vehicle-treated group (p < 0.05). Conclusions. Mitochondrial alterations, endothelial damage, and redox disbalance are key factors for aged rat mesenteric adipose tissue remodeling during Western diet consumption. Our results contributing to identifying powerful intervention by effective compound H2S-ASA, novel H2S-NSAIDs, which has the potential to modulate mesenteric metaflammation, vascular function by enhancement H2S synthesis and redox regulatory and cytoprotective activities

Duchenne's muscular dystrophy involves a defective transsulfuration pathway activity

Duchenne muscular dystrophy (DMD) is the most frequent X chromosome-linked disease caused by mutations in the gene encoding for dystrophin, leading to progressive and unstoppable degeneration of skeletal muscle tissues. Despite recent advances in the understanding of the molecular processes involved in the pathogenesis of DMD, there is still no cure. In this study, we aim at investigating the potential involvement of the transsulfuration pathway (TSP), and its by-end product namely hydrogen sulfide (H2S), in primary human myoblasts isolated from DMD donors and skeletal muscles of dystrophic (mdx) mice. In myoblasts of DMD donors, we demonstrate that the expression of key genes regulating the H2S production and TSP activity, including cystathionine γ lyase (CSE), cystathionine beta-synthase (CBS), 3 mercaptopyruvate sulfurtransferase (3-MST), cysteine dioxygenase (CDO), cysteine sulfonic acid decarboxylase (CSAD), glutathione synthase (GS) and γ -glutamylcysteine synthetase (γ-GCS) is reduced. Starting from these findings, using Nuclear Magnetic Resonance (NMR) and quantitative Polymerase Chain Reaction (qPCR) we show that the levels of TSP-related metabolites such as methionine, glycine, glutathione, glutamate and taurine, as well as the expression levels of the aforementioned TSP related genes, are significantly reduced in skeletal muscles of mdx mice compared to healthy controls, at both an early (7 weeks) and overt (17 weeks) stage of the disease. Importantly, the treatment with sodium hydrosulfide (NaHS), a commonly used H2S donor, fully recovers the impaired locomotor activity in both 7 and 17 old mdx mice. This is an effect attributable to the reduced expression of pro-inflammatory markers and restoration of autophagy in skeletal muscle tissues. In conclusion, our study uncovers a defective TSP pathway activity in DMD and highlights the role of H2S-donors for novel and safe adjuvant therapy to treat symptoms of DMD.

Hydrogen Sulfide (H2S) and Polysulfide (H2Sn) Signaling: The First 25 Years.

Since the first description of hydrogen sulfide (H2S) as a toxic gas in 1713 by Bernardino Ramazzini, most studies on H2S have concentrated on its toxicity. In 1989, Warenycia et al. demonstrated the existence of endogenous H2S in the brain, suggesting that H2S may have physiological roles. In 1996, we demonstrated that hydrogen sulfide (H2S) is a potential signaling molecule, which can be produced by cystathionine β-synthase (CBS) to modify neurotransmission in the brain. Subsequently, we showed that H2S relaxes vascular smooth muscle in synergy with nitric oxide (NO) and that cystathionine γ-lyase (CSE) is another producing enzyme. This study also opened up a new research area of a crosstalk between H2S and NO. The cytoprotective effect, anti-inflammatory activity, energy formation, and oxygen sensing by H2S have been subsequently demonstrated. Two additional pathways for the production of H2S with 3-mercaptopyruvate sulfurtransferase (3MST) from l- and d-cysteine have been identified. We also discovered that hydrogen polysulfides (H2Sn, n ≥ 2) are potential signaling molecules produced by 3MST. H2Sn regulate the activity of ion channels and enzymes, as well as even the growth of tumors. S-Sulfuration (S-sulfhydration) proposed by Snyder is the main mechanism for H2S/H2Sn underlying regulation of the activity of target proteins. This mini review focuses on the key findings on H2S/H2Sn signaling during the first 25 years.

Characterization of hyperglycemia due to sub-chronic administration of red ginseng extract via comparative global proteomic analysis

Ginseng (Panax ginseng Meyer) is commonly used as an herbal remedy worldwide. Few studies have explored the possible physiological changes in the liver although patients often self-medicate with ginseng preparations, which may lead to exceeding the recommended dose for long-term administration. Here, we analyzed changes in the hepatic proteins of mouse livers using quantitative proteomics after sub-chronic administration of Korean red ginseng (KRG) extract (control group and 0.5, 1.0, and 2.0 g/kg KRG) using tandem mass tag (TMT) 6‐plex technology. The 1.0 and 2.0 g/kg KRG groups exhibited signs of liver injury, including increased levels of aspartate transaminase (AST) and alanine aminotransferase (ALT) in the serum. Furthermore, serum glucose levels were significantly higher following KRG administration compared with the control group. Based on the upregulated proteins found in the proteomic analysis, we found that increased cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE) levels promoted greater hydrogen sulfide (H2S) synthesis in the liver. This investigation provides novel evidence that sub-chronic administration of KRG can elevate H2S production by increasing protein expression of CBS and CSE in the liver.

Effect of N,N-Dimethylglycine on Homocysteine Metabolism in Rats Fed Folate-Sufficient and Folate-Deficient Diets

ObjectiveThis study aimed to investigate the effects of N,N-dimethylglycine (DMG) on the concentration and metabolism of plasma homocysteine (pHcy) in folate-sufficient and folate-deficient rats. MethodsIn this study, 0.1% DMG was supplemented in 20% casein diets that were either folate-sufficient (20C) or folate-deficient (20CFD). Blood and liver of rats were subjected to assays of Hcy and its metabolites. Hcy and its related metabolite concentrations were determined using a liquid chromatographic system. ResultsFolate deprivation significantly increased pHcy concentration in rats fed 20C diet (from 14.19 ± 0.39 µmol/L to 28.49 ± 0.50 µmol/L; P < 0.05). When supplemented with DMG, pHcy concentration was significantly decreased (12.23 ± 0.18 µmol/L) in rats fed 20C diet but significantly increased (31.56 ± 0.59 µmol/L) in rats fed 20CFD. The hepatic methionine synthase activity in the 20CFD group was significantly lower than that in the 20C group; enzyme activity was unaffected by DMG supplementation regardless of folate sufficiency. The activity of hepatic cystathionine β-synthase (CBS) in the 20CFD group was decreased but not in the 20C group; DMG supplementation enhanced hepatic CBS activity in both groups, in which the effect was significant in the 20C group but not in the other group. ConclusionDMG supplementation exhibited hypohomocysteinemic effects under folate-sufficient conditions. By contrast, the combination of folate deficiency and DMG supplementation has deleterious effect on pHcy concentration.

Highly recurrent CBS epimutations in gastric cancer CpG island methylator phenotypes and inflammation

BackgroundCIMP (CpG island methylator phenotype) is an epigenetic molecular subtype, observed in multiple malignancies and associated with the epigenetic silencing of tumor suppressors. Currently, for most cancers including gastric cancer (GC), mechanisms underlying CIMP remain poorly understood. We sought to discover molecular contributors to CIMP in GC, by performing global DNA methylation, gene expression, and proteomics profiling across 14 gastric cell lines, followed by similar integrative analysis in 50 GC cell lines and 467 primary GCs.ResultsWe identify the cystathionine beta-synthase enzyme (CBS) as a highly recurrent target of epigenetic silencing in CIMP GC. Likewise, we show that CBS epimutations are significantly associated with CIMP in various other cancers, occurring even in premalignant gastroesophageal conditions and longitudinally linked to clinical persistence. Of note, CRISPR deletion of CBS in normal gastric epithelial cells induces widespread DNA methylation changes that overlap with primary GC CIMP patterns. Reflecting its metabolic role as a gatekeeper interlinking the methionine and homocysteine cycles, CBS loss in vitro also causes reductions in the anti-inflammatory gasotransmitter hydrogen sulfide (H2S), with concomitant increase in NF-κB activity. In a murine genetic model of CBS deficiency, preliminary data indicate upregulated immune-mediated transcriptional signatures in the stomach.ConclusionsOur results implicate CBS as a bi-faceted modifier of aberrant DNA methylation and inflammation in GC and highlights H2S donors as a potential new therapy for CBS-silenced lesions.

Genetics and Epigenetics of One-Carbon Metabolism Pathway in Autism Spectrum Disorder: A Sex-Specific Brain Epigenome?

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition affecting behavior and communication, presenting with extremely different clinical phenotypes and features. ASD etiology is composite and multifaceted with several causes and risk factors responsible for different individual disease pathophysiological processes and clinical phenotypes. From a genetic and epigenetic side, several candidate genes have been reported as potentially linked to ASD, which can be detected in about 10–25% of patients. Folate gene polymorphisms have been previously associated with other psychiatric and neurodegenerative diseases, mainly focused on gene variants in the DHFR gene (5q14.1; rs70991108, 19bp ins/del), MTHFR gene (1p36.22; rs1801133, C677T and rs1801131, A1298C), and CBS gene (21q22.3; rs876657421, 844ins68). Of note, their roles have been scarcely investigated from a sex/gender viewpoint, though ASD is characterized by a strong sex gap in onset-risk and progression. The aim of the present review is to point out the molecular mechanisms related to intracellular folate recycling affecting in turn remethylation and transsulfuration pathways having potential effects on ASD. Brain epigenome during fetal life necessarily reflects the sex-dependent different imprint of the genome-environment interactions which effects are difficult to decrypt. We here will focus on the DHFR, MTHFR and CBS gene-triad by dissecting their roles in a sex-oriented view, primarily to bring new perspectives in ASD epigenetics.

Involvement of HAND1 and CBS in maintenance of cardiac micro-architecture following obesity-induced heart failure

Purpose: To study the role of heart and neural crest derivatives expressed 1 (HAND1) and cystathionine-beta-synthase (CBS) in the maintenance of cardiac architecture following high fat dietinduced obesity.&#x0D; Methods: Mouse models of initial and critical heart disease were established by continuous feeding of high fat diet for 7 and 12 months, respectively. The expression of HAND1 and CBS were assayed using immunohistochemistry and Western blotting.&#x0D; Results: Obesity led to mild and severe forms of heart disease which were confirmed through histological imaging. Initial obesity resulted in cardiac tissue remodeling along with initial degeneration, while critical obesity resulted in tissue hardening. The expression of HAND1 was upregulated 4.3 folds in the mild form of cardiac failure, relative to marginal expression pattern of HAND1 in control tissue. However, as the disease progressed, the expression of HAND1 was limited in serve form of cardiac failure. Moreover, the expression of cystathionine beta-synthase (CBS) was upregulated 3.7-fold in the initial form of heart failure, but was subsequently reduced in serve form of heart disease.&#x0D; Conclusion: These results reveal that in high fat diet-induced cardiac stress, the over-expressions of HAND1 and CBS at the initial stages induce extensive alterations in cardiac architecture.

Structural insight into the unique conformation of cystathionine b-synthase from Toxoplasma gondii

Structural insight into the unique conformation of cystathionine b-synthase from Toxoplasma gondii

Recurrent dislocation of binocular crystal lenses in a patient with cystathionine beta-synthase deficiency

BackgroundEctopia lentis is the common ocular manifestation of homocystinuria resulting from cystathionine beta-synthase (CBS) deficiency which has a high risk of thromboembolic complications.Case presentationThe present study reports the case of a teenager with recurrent lens dislocation and glaucoma. He was diagnosed with CBS deficiency according to a high level of serum homocysteine and compound heterozygous mutations at two different positions on the CBS gene. Antiglaucoma eyedrops and a mydriatic successfully controlled the intraocular pressure, while oral pyridoxine and betaine uptake lowered the serum homocysteine level effectively.ConclusionsChildren with CBS deficiency may suffer from ectopia lentis, glaucoma and/or amblyopia. We firstly discovered a new mutation of CBS c. 697 T > G which had not been reported before. The patient was pyridoxine responsive and well controlled by medicine.

Association of methylenetetrahydrofolate reductase (MTHFR) and cystathionine β-synthase (CBS) genes promoter methylation pattern with the risk of essential hypertension

Methylenetetrahydrofolate reductase (MTHFR) and cystathionine β-synthase (CBS) are key enzymes in the metabolism of homocysteine pathway whose dysfunction can lead to essential hypertension (EH). This study aimed to investigate the possible association of MTHFR and CBS genes promoter methylation patterns with the risk of EH. We also aimed to search differentially expressed microRNAs (miRs) and demonstrate the role of miRs in the aberrant DNA methylation in essential hypertensive patients by targeting DNA methyltransferases (DNMTs).20 essential hypertensive patients and 20 healthy controls were selected. DNA methylation levels of 10 CpG dinucleotides on MTHFR and 19 CpG dinucleotides on CBS genes promoter was measured using Bisulfite-Sequencing PCR (BSP). The GSE118578 profile was downloaded from the GEO database to identify differentially expressed miRs in hypertensive patients and R statistical software was used to analyze the data. Enrichment analysis was conducted to predict target genes using databases of Targetscan, and miRDB-MicroRNA Target Prediction Database.No significant association between MTHFR gene methylation and EH was observed. There was a significant association between one of the CpG sites of CBS gene promoter (CpG19 (+1035C)) and EH [OR = 5.3(0.895–31.393), p = 0.047]. Furthermore, we reported a list of miRs that may have an essential role in regulating DNA methylation by targeting DNMTs.Our findings showed that hypermethylation of CpG19 (+1035C) of CBS gene promoter could increase the risk of EH. Methylation status of MTHFR gene had no significant association with EH. Also, in-silico investigation showed that miRs may affect aberrant genes methylation through altering DNMTs biogenesis.

Analysis of differential neonatal lethality in cystathionine β-synthase deficient mouse models using metabolic profiling.

Cystathionine beta-synthase (CBS) is a key enzyme of the trans-sulfuration pathway that converts homocysteine to cystathionine. Loss of CBS activity due to mutation results in CBS deficiency, an inborn error of metabolism characterized by extreme elevation of plasma total homocysteine (tHcy). C57BL6 mice containing either a homozygous null mutation in the cystathionine β-synthase (Cbs-/- ) gene or an inactive human CBS protein (Tg-G307S Cbs-/- ) are born in mendelian numbers, but the vast majority die between 18 and 21 days of age due to liver failure. However, adult Cbs null mice that express a hypomorphic allele of human CBS as a transgene (Tg-I278T Cbs-/- ) show almost no neonatal lethality despite having serum tHcy levels similar to mice with no CBS activity. Here, we characterize liver and serum metabolites in neonatal Cbs+/- , Tg-G307S Cbs-/- , and Tg-I278T Cbs-/- mice at 6, 10, and 17 days of age to understand this difference. In serum, we observe similar elevations in tHcy in both Tg-G307S Cbs-/- and Tg-I278T Cbs-/- compared to control animals, but methionine is much more severely elevated in Tg-G307S Cbs-/- mice. Large scale metabolomic analysis of liver tissue confirms that both methionine and methionine-sulfoxide are significantly more elevated in Tg-G307S Cbs-/- animals, along with significant differences in several other metabolites including hexoses, amino acids, other amines, lipids, and carboxylic acids. Our data are consistent with a model that the neonatal lethality observed in CBS-null mice is driven by excess methionine resulting in increased stress on a variety of related pathways including the urea cycle, TCA cycle, gluconeogenesis, and phosphatidylcholine biosynthesis.

Decreased Cortical Nrf2 Gene Expression in Autism Spectrum Disorder and its Relationship to Thiol and Cobalamin status

Background The etiology of Autism spectrum disorder (ASD) is suspected to involve redox imbalances. In accordance with this, we previously published that sulfur metabolites in the methionine cycle and transsulfuration pathway were dysregulated in ASD frontal cortex. This was accompanied by disturbed vitamin B12 or cobalamin status. Cobalamin abundance and levels of the bioactive species methylcobalamin (MeCbl) were decreased, while levels of oxidized inert hydroxocobalamin (OHCbl) were increased in those tissues. Cellular cobalamin status is dependent on antioxidant availability. Reports have described decreased expression or activity of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in blood cells in ASD. Nrf2 is a transcription factor that promotes transcription of genes involved in maintaining antioxidant and detoxification status. We followed up on our postmortem study by performing real-time quantitative polymerase chain reaction (RT-qPCR) to investigate expression redox-linked genes. Genes included Nrf2 (NFE2L2), cystathionine beta synthase (CBS), cystathionine gamma-lyase (CTH), solute carrier family 1 member 1 (SLC1A1), glutathione synthetase (GSS), and glutathione reductase (GSR). We then searched for correlations among gene expression, thiols, and cobalamins to understand what factors may contribute to deranged sulfur and cobalamin metabolism in the brain in ASD. Methods RNA was isolated from control and ASD frontal cortex tissue using RNAqueous-4PCR kit manufactured by Ambion. Complementary DNA (cDNA) was synthesized with a Roche First Strand cDNA Synthesis kit. RT-qPCR was performed with a Roche LightCycler 480 model. Gene expression was normalized to glyceraldehyde 3-phosphate dehydrogenase. Bioinformatics searches were conducted with data downloaded from the consensus RNA dataset compiled by The Human Protein Atlas. Data were analyzed with Microsoft Excel and GraphPad Prism. Results NFE2L2, CBS, CTH, SLC1A1, and GSS RNA were decreased in ASD frontal cortex. Correlation analyses of pooled control and ASD data revealed strong associations between NFE2L2, cobalamin abundance, methionine, S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH). An association was also found with the transsulfuration metabolite cystathionine. Homocysteine (HCY) and OHCbl were inversely correlated with NFE2L2 expression. We decided to use a bioinformatics approach to further probe a general connection between Nrf2 and cobalamin status, utilizing cobalamin levels in various tissues published by Hsu et al. in 1966. Data obtained from The Human Protein Atlas revealed impressive associations between the expression of Nrf2-regulated genes, NFE2L2 expression, and tissue cobalamin abundance as described by Hsu et al. Conclusion Our RT-qPCR data support a role for decreased Nrf2 activity as an important feature of ASD. We further find that NFE2L2 expression is related to the metabolic patterns we characterized in ASD frontal cortex. Results of our bioinformatics inquiry suggest a potential causal role for Nrf2 that requires further investigation.

Metformin Induced Oxidative Stress Alters Transsulfuration Pathway and Inhibits Prostate Cancer Cell Growth

Objective To determine the role of metformin in regulating intracellular redox status and cell growth in prostate cancer cells Background : Prostate cancer is the second leading cause of cancer-related death among males in the United States. Despite several advances in treatment options, there are several underlying challenges that affect prostate cancer therapy, including patient age, cancer resistance and undesirable side effects. Moreover, current treatment options focus on two or more cellular targets, such as, androgen synthesis, DNA repair enzymes and immune cells. Such cellular targets bypass the underlying supportive metabolic and molecular phenotypes that contribute to a cancer cell's ability to evade apoptosis, proliferate, and develop chemoresistance. Over the last decade, both preclinical and clinical studies have indicated the potential of metformin in prostate cancer therapy. Notably, these extensive studies demonstrated metformin's pleiotropic effects on several molecular and metabolic pathways such as androgen signaling, cell cycle and cellular bioenergetics, including its unique ability to activate the energy sensor 5 AMP activated kinase (AMPK). We previously demonstrated that metformin alters mitochondrial function in LNCaP prostate cancer cells resulting in elevated glycolysis. In light of this, we hypothesized that metformin induced oxidative stress, modulates prostate cancer cell survival, and is involved in its antiproliferative effects via the transsulfuration pathway. Methods : Using Seahorse XP extracellular analysis, we measured LNCaP prostate cancer cellular bioenergetics oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in the presence of metformin and SBI0206965 (an AMPK inhibitor). RT-PCR, Liquid Chromatography/ Mass Spectrophotometry (LC/MS), Trypan Blue Exclusion and MTT assays were used to assess the effect of metformin on intracellular redox status and prostate cancer survival. Additionally, we also measured transsulfuration-related enzymatic activities using an ELISA Assay. Results Metformin altered prostate cancer cellular bioenergetics resulting in decreased OCR and increased ECAR, reflecting oxidative phosphorylation and glycolytic activity, respectively. LC/MS analysis of metformin-treated cells showed a significant reduction in GSH/GSSG ratio and metabolite levels associated with the transsulfuration pathway such as glutathione (GSH) and cystathionine (CYS). These low levels of GSH and CYS were consistent with an increase in the gene expression of transsulfuration related enzymes, cystathionine beta synthase (CBS) and cystathionine gamma-lyase (CSE). Additionally, metformin increased the gene expression of the glutathione synthesis-related enzyme γ-glutamyl cysteine ligase (GCL), with no observable change in glutathione synthetase (GSS) gene expression. Notably, MTT and trypan blue exclusion assays indicated that metformin significantly decreased cell viability and had an anti-proliferative effect on LNCaP prostate cancer cells. Conclusion :Metformin induced oxidative stress modulates transsulfuration and glutathione synthesis pathways and exerts antiproliferative effects in LNCaP prostate cancer cells.

Hydrogen sulfide alleviates the anxiety-like and depressive-like behaviors of type 1 diabetic mice via inhibiting inflammation and ferroptosis

Studies reported that sodium hydrosulfide (NaHS) can remit the depressive-like and anxiety-like behaviors induced by type 1 diabetes mellitus (T1DM). However, the mechanism is still unclear. In this study, we aimed to investigate the mechanism of NaHS on T1DM. Mice were randomly divided into four groups, including the control group (CON group), DM group, DM + 5.6 mg/kg NaHS group, and CON + 5.6 mg/kg NaHS group. Data showed that NaHS did attenuate the depressive-like and anxiety-like behaviors by OFT, EPM test, FST, and TST. Results suggest that NaHS markedly alleviated the ferroptosis in the prefrontal cortex (PFC) of diabetic mice by reducing iron deposition and oxidative stress, increasing the expression of GPX4 and SLC7A11. Moreover, NaHS could dampen the activation of microglias and the release of pro-inflammatory cytokines, enhance the protein expression of sirtuin 6 (Sirt6) and the interaction between Sirt6 and the acetylation of histoneH3 lysine9 (H3K9ac), and decrease the protein expressions of the Notch1 receptor and H3K9ac. In vitro experiment, NaHS ameliorated the ferroptosis via increasing the protein expressions of SLC7A11, glutathione peroxidase 4 (GPX4), and cystathionine β-synthase (CBS), reducing the pro-inflammatory cytokines, decreasing the levels of Fe2+, MDA, ROS, and lipid ROS. In conclusion, our results suggested that NaHS did alleviate anxiety-like and depressive-like behaviors. It can inhibit inflammation via modulating Sirt6 and was able to decrease the ferroptosis in the PFC of type 1 diabetic mice and the BV2 cells.

Hydrogen sulfide restores cardioprotective effects of remote ischemic preconditioning in aged rats via HIF-1α/Nrf2 signaling pathway

The present study explored the therapeutic potential of hydrogen sulfide (H2S) in restoring aging-induced loss of cardioprotective effect of remote ischemic preconditioning (RIPC) along with the involvement of signaling pathways. The left hind limb was subjected to four short cycles of ischemia and reperfusion (IR) in young and aged male rats to induce RIPC. The hearts were subjected to IR injury on the Langendorff apparatus after 24 h of RIPC. The measurement of lactate dehydrogenase, creatine kinase and cardiac troponin served to assess the myocardial injury. The levels of H2S, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), nuclear factor erythroid 2-related factor 2 (Nrf2), and hypoxia-inducible factor (HIF-1α) were also measured. There was a decrease in cardioprotection in RIPC-subjected old rats in comparison to young rats along with a reduction in the myocardial levels of H2S, CBS, CSE, HIF-1α, and nuclear: cytoplasmic Nrf2 ratio. Supplementation with sodium hydrogen sulfide (NaHS, an H2S donor) and l-cysteine (H2S precursor) restored the cardioprotective actions of RIPC in old hearts. It increased the levels of H2S, HIF-1α, and Nrf2 ratio without affecting CBS and CSE. YC-1 (HIF-1α antagonist) abolished the effects of NaHS and l-cysteine in RIPC-subjected old rats by decreasing the Nrf2 ratio and HIF-1α levels, without altering H2S.The late phase of cardioprotection of RIPC involves an increase in the activity of H2S biosynthetic enzymes, which increases the levels of H2S to upregulate HIF-1α and Nrf2. H2S has the potential to restore aging-induced loss of cardioprotective effects of RIPC by upregulating HIF-1α/Nrf2 signaling.

Uremic Toxin Indoxyl Sulfate Impairs Hydrogen Sulfide Formation in Renal Tubular Cells

Hydrogen sulfide (H2S) is the third gasotransmitter that recognized as a cytoprotectant. Recent study demonstrated that exogenous supplement of H2S ameliorates functional insufficiency in chronic kidney disease (CKD). However, how H2S system is impaired by CKD has not been elucidated. The uremic toxin indoxyl sulfate (IS) is known to accumulate in CKD patients and harm the renal tubular cells. This study therefore treated proximal tubular cells LLC-PK1 with IS to see how IS affects H2S formation. Our results showed that H2S release from LLC-PK1 cells was markedly attenuated by IS when compared to that in control cells. The H2S donors NaHS and GYY-4137 significantly attenuated IS-induced tubular damage by enhancing cell survival in dose-dependent manners. Inhibition of remnant H2S production in the IS-treated cells by AOAA exacerbated tubulotoxicity. These results clearly indicated IS impairs H2S formation. We then examined protein and mRNA expression of H2S-producing enzymes cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST). IS downregulated both CBS and 3-MST protein and mRNA expressions after 24-72 h of treatment. CSE protein and mRNA levels were lowered at 24 h and 24-48 h, respectively, by IS. The low expression of CBS and 3-MST at both protein and mRNA levels could be reversed by AhR inhibition. As transcription factor specificity protein 1 (Sp1) regulates gene expression of H2S-producing enzymes, we further showed that IS significantly decreased the DNA binding activity of Sp1, this however did not affect Sp1 protein expression. AhR inhibition reversed low Sp1 activity caused by IS. Together these results, we conclude that IS activates AhR which then attenuates Sp1 function on regulation of H2S-producing enzyme expression. Attenuation of H2S formation contributed to uremic toxin-mediated renal tubular cell damage.

Glucose-induced decrease of cystathionine β-synthase mediates renal injuries.

Exogenous hydrogen sulfide (H2 S) protects kidneys from diabetic injuries in animal models. In order to explore the role of endogenous H2 S in diabetic nephropathy, we determined the renal H2S producing enzymes in vivo and in vitro. In diabetic mice, H2 S levels in blood and kidney were decreased while cystathionine β-synthase (CBS), mainly located in mouse renal proximal convoluted tubules (PCT), was reduced selectively. In cultured mouse PCT cells treated with high glucose, CBS protein and activity was reduced while ubiquitinated CBS was increased, which was abolished by a proteasome inhibitor MG132 at 1 hour; high glucose drove CBS colocalized with proteasome 26S subunit ATPase6, indicating an involvement of ubiquitination proteasome degradation. At 48 hours, high glucose also selectively decreased CBS protein, concentration-dependently, but increased the ubiquitination of CBS; silence of CBS by siRNA increased nitrotyrosine, a marker for protein oxidative injury. Nitrotyrosine was also increased by high glucose treatments. The increases of nitrotyrosine either by cbs-siRNA or by glucose were restored by GYY4137, indicating that the H2 S donor may protect kidney from oxidative injury induced by CBS deficiency. In diabetic kidneys, ubiquitinated CBS and nitrotyrosine were increased but restored by GYY4137. The treatment also ameliorated albuminuria and renal morphologic changes in diabetic mice. Our findings suggest that high glucose induces reduction of renal CBS protein and activity in vivo and in vitro that is critical to the pathogenesis of diabetic kidney disease.

Suspecting classical homocystinuria in an adolescent born before the newborn screening program

Introduction: Classical homocystinuria (HCU) is an autosomal recessive disorder caused by a deficiency in the cystathionine beta-synthase enzyme and associated with a high probability of vascular complications. Herein is presented the case of an adolescent diagnosed with HCU during cerebral venous sinus thrombosis (CVST) study. Case Report: A 14-year-old girl presented with thrombophilia screening tests suggestive of HCU during CVST study. After referral to an Inherited Metabolic Diseases Unit, she started supplementation with pyridoxine, folic acid, vitamin B12, betaine anhydrous, and cysteine and was advised to restrict natural proteins and methionine from diet. Genetic analysis revealed a homozygous CBS mutation (c.572C>T (p.T191M) with c.699C>T (p.Y233Y) polymorphism. Discussion: In adolescents born before 2004 (year of implementation of the Portuguese newborn screening program), HCU should be considered when studying hypercoagulability syndromes, as it is a treatable condition and treatment can prevent major morbidity and mortality causes.