Cystathionine γ lyase S-sulfhydrates Drp1 to ameliorate heart dysfunction

Protective Role of H2S in High Glucose-Induced Cardiomyocyte and Endothelial Cell Dysfunction: A Mechanistic Review

Hydrogen sulfide (H2S), recognized as a significant gasotransmitter, has been shown to effectively reduce damage to cardiomyocytes and endothelial cells caused by diabetes. Its protective effects primarily stem from several mechanisms, including S-sulfhydration of proteins, reduction of cell death, alleviation of mitochondrial damage, improvement of ion channel dysfunction, interaction with nitric oxide, and modulation of angiogenesis. H2S is synthesized by cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST), whose expression is significantly reduced under diabetic conditions, including experimental high-glucose treatment in cells and diabetes mellitus animal models. This review summarizes the protective role of H2S and its donors in these pathological processes, highlights existing research gaps-including challenges in the targeted delivery of H2S donors, limited clinical translation, and incomplete mechanistic understanding-and discusses future directions for developing targeted H2S-based therapeutic strategies.

Sodium aescinate induces hepatotoxicity through apoptosis and ferroptosis by inhibiting the Nrf2/CTH pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The seed of Aesculus wilsonii Rehd., also known as Suoluozi in China, is a traditional Chinese herb included in the Pharmacopoeia of China (2020). Sodium aescinate (SA) is derived from the Aesculus wilsonii Rehd.'s seeds and is extensively used in clinical practice.

AIM OF THE STUDY

The study investigated the involvement of the Nrf2/CTH pathway in SA-induced hepatotoxicity and explored potential strategies for alleviating SA-induced liver damage.

MATERIALS AND METHODS

The ICR mice and AML12 mouse hepatocytes were exposed to SA. The levels of Fe2+, cysteine (Cys), glutathione (GSH), hydrogen sulfide (H2S), ROS, lipid peroxides and caspase-3 activity were assessed. The effects of SA on signaling pathways related to ferroptosis and apoptosis were examined. Furthermore, genetic modification or agonists of Nrf2 and CTH were co-treated with SA.

RESULTS

SA triggered ferroptosis and apoptosis in AML12 cells and mouse livers, characterized by a decline in Cys, GSH, and H2S levels, as well as accumulation of Fe2+, ROS and lipid peroxides, mitochondrial dysfunction, and chromatin condensation. SA decreased Nrf2, CTH, and Bcl-2 levels, elevated Bax levels, and activated caspase-9/3. Overexpression of Nrf2 or CTH, or NAC supplementation alleviated SA-induced ferroptosis by upregulating Cys and GSH levels. Overexpression of Nrf2 or CTH, or NaHS supplementation increased H2S levels, which reduced the interaction between p616-Drp1 and VDAC1 by enhancing Drp1 S-sulfenylation, thereby alleviating SA-induced mitochondrial-dependent apoptosis. Furthermore, DMF or Met mitigated SA-induced hepatotoxicity by activating the Nrf2/CTH pathway.

CONCLUSIONS

SA triggers oxidative stress, mitochondrial dysfunction, apoptosis, and ferroptosis, ultimately leading to liver damage by suppressing the Nrf2/CTH pathway.

Polysulfur-based bulking of dynamin-related protein 1 prevents ischemic sulfide catabolism and heart failure in mice

The presence of redox-active molecules containing catenated sulfur atoms (supersulfides) in living organisms has led to a review of the concepts of redox biology and its translational strategy. Glutathione (GSH) is the body's primary detoxifier and antioxidant, and its oxidized form (GSSG) has been considered as a marker of oxidative status. However, we report that GSSG, but not reduced GSH, prevents ischemic supersulfide catabolism-associated heart failure in male mice by electrophilic modification of dynamin-related protein (Drp1). In healthy exercised hearts, the redox-sensitive Cys644 of Drp1 is highly S-glutathionylated. Nearly 40% of Cys644 is normally polysulfidated, which is a preferential target for GSSG-mediated S-glutathionylation. Cys644 S-glutathionylation is resistant to Drp1 depolysulfidation-dependent mitochondrial hyperfission and myocardial dysfunction caused by hypoxic stress. MD simulation of Drp1 structure and site-directed mutagenetic analysis reveal a functional interaction between Cys644 and a critical phosphorylation site Ser637, through Glu640. Bulky modification at Cys644 via polysulfidation or S-glutathionylation reduces Drp1 activity by disrupting Ser637-Glu640-Cys644 interaction. Disruption of Cys644 S-glutathionylation nullifies the cardioprotective effect of GSSG against heart failure after myocardial infarction. Our findings suggest a therapeutic potential of supersulfide-based Cys bulking on Drp1 for ischemic heart disease.

Hydrogen sulfide mitigates mitochondrial dysfunction and cellular senescence in diabetic patients: Potential therapeutic applications

Diabetes induces a pro-aging state characterized by an increased abundance of senescent cells in various tissues, heightened chronic inflammation, reduced substance and energy metabolism, and a significant increase in intracellular reactive oxygen species (ROS) levels. This condition leads to mitochondrial dysfunction, including elevated oxidative stress, the accumulation of mitochondrial DNA (mtDNA) damage, mitophagy defects, dysregulation of mitochondrial dynamics, and abnormal energy metabolism. These dysfunctions result in intracellular calcium ion (Ca2+) homeostasis disorders, telomere shortening, immune cell damage, and exacerbated inflammation, accelerating the aging of diabetic cells or tissues. Hydrogen sulfide (H2S), a novel gaseous signaling molecule, plays a crucial role in maintaining mitochondrial function and mitigating the aging process in diabetic cells. This article systematically explores the specific mechanisms by which H2S regulates diabetes-induced mitochondrial dysfunction to delay cellular senescence, offering a promising new strategy for improving diabetes and its complications.

Insufficient S-sulfhydration of serum and glucocorticoid-regulated kinase 1 participates in hyperhomocysteinemia-induced liver injury

BACKGROUND & AIMS

Previous studies have established that hyperhomocysteinemia (HHcy) significantly contributes to the development of non-alcoholic steatohepatitis (NASH). Conversely, hydrogen sulfide (H2S) has shown potential in mitigating NASH. Despite these findings, it remains uncertain whether H2S can serve as a therapeutic agent against HHcy-induced liver damage.

METHODS

Mice were fed a high-methionine diet to induce HHcy and HepG2 cells were exposed to homocysteine (Hcy). In both models, we assessed liver injury, H2S concentration, and autophagy levels. For rescue, sodium hydrosulfide (NaHS), an H2S donor, was used to test its potential in reversing hepatic pathological features induced by HHcy.

RESULTS

1) Hcy accumulation led to liver damage and increased autophagy. This was linked to insufficient S-sulfhydration of serum and glucocorticoid-regulated kinase 1 (SGK1) at Cys244 and Cys282, a crucial autophagy regulator. The deficiency in S-sulfhydration was resulted from downregulation of cystathionine-γ-lyase (CSE) and subsequent H2S decrease, leading to SGK1 inactivation. 2) Administration of NaHS reduced the liver damage caused by high Hcy levels and restored H2S levels, promoting the S-sulfhydration and activation of SGK1. 3) Pharmacological inhibition of SGK1 induced autosis, a specific type of cell death caused by overactivation of autophagy. Conversely, a constitutively active mutant of SGK1 (SGK1S422D) significantly decreased autophagy and improved cell viability.

CONCLUSIONS

NaHS supplementation mitigates HHcy-induced liver injury by downregulating hepatic autophagy through the S-sulfhydration and activation of SGK1. This post-translational modification by H2S holds promise as a therapeutic approach for HHcy-induced liver injury.

Cr(VI) induced hepatocyte apoptosis through the CTH/H2S/Drp1 signaling pathway

Hexavalent chromium [Cr(VI)] is a highly hazardous heavy metal with multiple toxic effects. Occupational studies indicate that its accumulation in humans can lead to liver damage. However, the exact mechanism underlying Cr(VI)-induced hepatotoxicity remains unknown. In this study, we explored the role of CTH/H2S/Drp1 pathway in Cr(VI)-induced oxidative stress, mitochondrial dysfunction, apoptosis, and liver injury. Our data showed that Cr(VI) triggered apoptosis, accompanied by H2S reduction, reactive oxygen species (ROS) accumulation, and mitochondrial dysfunction in both AML12 cells and mouse livers. Moreover, Cr(VI) reduced cystathionine γ-lyase (CTH) and dynamin related protein 1 (Drp1) S-sulfhydration levels, and elevated Drp1 phosphorylation levels at Serine 616, which promoted Drp1 mitochondrial translocation and Drp1-voltage-dependent anion channel 1 (VDAC1) interactions, ultimately leading to mitochondria-dependent apoptosis. Elevated hydrogen sulfide (H2S) levels eliminated Drp1 phosphorylation at Serine 616 by increasing Drp1 S-sulfhydration, thereby preventing Cr(VI)-induced Drp1-VDAC1 interaction and hepatotoxicity. These findings indicated that Cr(VI) induced mitochondrial apoptosis and hepatotoxicity by inhibiting CTH/H2S/Drp1 pathway and that targeting either CTH/H2S pathway or Drp1 S-sulfhydration could serve as a potential therapy for Cr(VI)-induced liver injury.

Systematic analysis of the global characteristics and reciprocal effects of S-nitrosylation and S-persulfidation in the human proteome

Gasotransmitter-mediated cysteine post-translational modifications, including S-nitrosylation (SNO) and S-persulfidation (SSH), play crucial roles and interact in various biological processes. However, there has been a delay in appreciating the interactional rules between SNO and SSH. Here, all human S-nitrosylated and S-persulfidated proteomic data were curated, and comprehensive analyses from multiple perspectives, including sequence, structure, function, and exact protein impacts (e.g., up-/down-regulation), were performed. Although these two modifications collectively regulated a wide array of proteins to jointly maintain redox homeostasis, they also exhibited intriguing differences. First, SNO tended to be more accessible and functionally clustered in pathways associated with cell damage repair and other protein modifications, such as phosphorylation and ubiquitination. Second, SSH preferentially targeted cysteines in disulfide bonds and modulated tissue development and immune-related pathways. Finally, regardless of whether SNO and SSH occupied the same position of a given protein, their combined effect tended to be suppressive when acting synergistically; otherwise, SNO likely inhibited while SSH activated the target protein. Indeed, a side-by-side comparison of SNO and SSH shed light on their globally reciprocal effects and provided a reference for further research on gasotransmitter-mediated biological effects.

Cardiac remodeling: novel pathophysiological mechanisms and therapeutic strategies

Morphological and structural remodeling of the heart, including cardiac hypertrophy and fibrosis, has been considered as a therapeutic target for heart failure for approximately three decades. Groundbreaking heart failure medications demonstrating reverse remodeling effects have contributed significantly to medical advancements. However, nearly 50% of heart failure patients still exhibit drug resistance, posing a challenge to the healthcare system. Recently, characteristics of heart failure resistant to ARBs and β-blockers have been defined, highlighting preserved systolic function despite impaired diastolic function, leading to the classification of heart failure with preserved ejection fraction (HFpEF). The pathogenesis and aetiology of HFpEF may be related to metabolic abnormalities, as evidenced by its mimicry through endothelial dysfunction and excessive intake of high-fat diets. Our recent findings indicate a significant involvement of mitochondrial hyper-fission in the progression of heart failure. This mitochondrial pathological remodeling is associated with redox imbalance, especially hydrogen sulphide accumulation due to abnormal electron leak in myocardium. In this review, we also introduce a novel therapeutic strategy for heart failure from the current perspective of mitochondrial redox-metabolic remodeling.

Efficacy of L-cysteine in increasing circulatory hydrogen sulfide, nitrite, and 25(OH)VD levels in ZDF rats and in vitro treatment of H2S and NO2 in upregulating VD hydroxylase genes in monocytes

Dairy products, such as whey proteins, have been effectively utilized to enhance the effectiveness of vitamin D fortification and optimize circulating 25(OH)VD levels. Whey protein is rich in L-cysteine (LC) which is the precursor of hydrogen sulfide (H2S), enhances glutathione (GSH) biosynthesis, and promotes positive nitrogen balance. Zucker diabetic rats (ZDF) were used as a model in this study, to examine the hypothesis that LC supplementation enhances blood levels of H2S and nitrite (NO2) while reducing inflammation biomarkers. Rats were gavaged daily (orally) with either saline placebo or L-cysteine along with a high-calorie diet starting at 6 weeks of age. Fasting blood levels showed LC supplementation significantly increased circulatory levels of H2S and NO2 compared with placebo rats. LC supplementation increased plasma concentration of 25(OH)VD and vitamin C and lowered leptin and body weight gain in ZDF rats. Furthermore, to assess the impact of H2S and NO2 in raising 25(OH)VD levels, the in vitro effect of H2S/NO2 on vitamin D metabolism genes was examined using THP-1 monocytes. The exogenous H2S and NO2 treatment upregulated the relative expression of CYP2R1 and CYP27B1 genes in cultured monocytes. This study suggests a potential mechanism for the observed increase in circulating 25(OH)VD levels following L-cysteine supplementation.

Supersulfide catabolism participates in maladaptive remodeling of cardiac cells

The atrophic myocardium resulting from mechanical unloading and nutritional deprivation is considered crucial as maladaptive remodeling directly associated with heart failure, as well as interstitial fibrosis. Conversely, myocardial hypertrophy resulting from hemodynamic loading is perceived as compensatory stress adaptation. We previously reported the abundant presence of highly redox-active polysulfide molecules, termed supersulfide, with two or more sulfur atoms catenated in normal hearts, and the supersulfide catabolism in pathologic hearts after myocardial infarction correlated with worsened prognosis of heart failure. However, the impact of supersulfide on myocardial remodeling remains unclear. Here, we investigated the involvement of supersulfide metabolism in cardiomyocyte remodeling, using a model of adenosine 5'-triphosphate (ATP) receptor-stimulated atrophy and endothelin-1 receptor-stimulated hypertrophy in neonatal rat cardiomyocytes. Results revealed contrasting changes in intracellular supersulfide and its catabolite, hydrogen sulfide (H2S), between cardiomyocyte atrophy and hypertrophy. Stimulation of cardiomyocytes with ATP decreased supersulfide activity, while H2S accumulation itself did not affect cardiomyocyte atrophy. This supersulfide catabolism was also involved in myofibroblast formation of neonatal rat cardiac fibroblasts. Thus, unraveling supersulfide metabolism during myocardial remodeling may lead to the development of novel therapeutic strategies to improve heart failure.

Hydrogen sulfide mitigates ox‑LDL‑induced NLRP3/caspase‑1/GSDMD dependent macrophage pyroptosis by S‑sulfhydrating caspase‑1

Macrophage pyroptosis mediates vascular inflammation and atherosclerosis (AS). Hydrogen sulfide (H2S) exerts a protective role in preventing inflammation and AS. However, its molecular mechanisms of regulating the pyroptosis signaling pathway and inhibiting macrophage pyroptosis remain unexplored. The present study aimed to determine whether H2S mitigates macrophage pyroptosis by downregulating the pyroptosis signaling pathway and S‑sulfhydrating caspase‑1 under the stimulation of oxidized low‑density lipoprotein (ox‑LDL), a pro‑atherosclerotic factor. Macrophages derived from THP‑1 monocytes were pre‑treated using exogenous H2S donors sodium hydrosulfide (NaHS) and D,L‑propargylglycine (PAG), a pharmacological inhibitor of endogenous H2S‑producing enzymes, alone or in combination. Subsequently, cells were stimulated with ox‑LDL or the desulfhydration reagent dithiothreitol (DTT) in the presence or absence of NaHS and/or PAG. Following treatment, the levels of H2S in THP‑1 derived macrophages were measured by a methylene blue colorimetric assay. The pyroptotic phenotype of THP‑1 cells was observed and evaluated by light microscopy, Hoechst 33342/propidium iodide fluorescent staining and lactate dehydrogenase (LDH) release assay. Caspase‑1 activity in THP‑1 cells was assayed by caspase‑1 activity assay kit. Immunofluorescence staining was used to assess the accumulation of active caspase‑1. Western blotting and ELISA were performed to determine the expression of pyroptosis‑specific markers (NLRP3, pro‑caspase‑1, caspase‑1, GSDMD and GSDMD‑N) in cells and the secretion of pyroptosis‑related cytokines [interleukin (IL)‑1β and IL‑18] in the cell‑free media, respectively. The S‑sulfhydration of pro‑caspase‑1 in cells was assessed using a biotin switch assay. ox‑LDL significantly induced macrophage pyroptosis by activating the pyroptosis signaling pathway. Inhibition of endogenous H2S synthesis by PAG augmented the pro‑pyroptotic effects of ox‑LDL. Conversely, exogenous H2S (NaHS) ameliorated ox‑LDL‑and ox‑LDL + PAG‑induced macrophage pyroptosis by suppressing the activation of the pyroptosis signaling pathway. Mechanistically, ox‑LDL and the DTT increased caspase‑1 activity and downstream events (IL‑1β and IL‑18 secretion) of the caspase‑1‑dependent pyroptosis pathway by reducing S‑sulfhydration of pro‑caspase‑1. Conversely, NaHS increased S‑sulfhydration of pro‑caspase‑1, reducing caspase‑1 activity and caspase‑1‑dependent macrophage pyroptosis. The present study demonstrated the molecular mechanism by which H2S ameliorates macrophage pyroptosis by suppressing the pyroptosis signaling pathway and S‑sulfhydration of pro‑caspase‑1, thereby suppressing the generation of active caspase-1 and activity of caspase-1.

The pathological mechanisms and potential therapeutic drugs for myocardial ischemia reperfusion injury

BACKGROUND

Cardiovascular disease is the main cause of death and disability, with myocardial ischemia being the predominant type that poses a significant threat to humans. Reperfusion, an essential therapeutic approach, promptly reinstates blood circulation to the ischemic myocardium and stands as the most efficacious clinical method for myocardial preservation. Nevertheless, the restoration of blood flow associated with this process can potentially induce myocardial ischemia-reperfusion injury (MIRI), thereby diminishing the effectiveness of reperfusion and impacting patient prognosis. Therefore, it is of great significance to prevent and treat MIRI.

PURPOSE

MIRI is an important factor affecting the prognosis of patients, and there is no specific in-clinic treatment plan. In this review, we have endeavored to summarize its pathological mechanisms and therapeutic drugs to provide more powerful evidence for clinical application.

METHODS

A comprehensive literature review was conducted using PubMed, Web of Science, Embase, Medline and Google Scholar with a core focus on the pathological mechanisms and potential therapeutic drugs of MIRI.

RESULTS

Accumulated evidence revealed that oxidative stress, calcium overload, mitochondrial dysfunction, energy metabolism disorder, ferroptosis, inflammatory reaction, endoplasmic reticulum stress, pyroptosis and autophagy regulation have been shown to participate in the process, and that the occurrence and development of MIRI are related to plenty of signaling pathways. Currently, a range of chemical drugs, natural products, and traditional Chinese medicine (TCM) preparations have demonstrated the ability to mitigate MIRI by targeting various mechanisms.

CONCLUSIONS

At present, most of the research focuses on animal and cell experiments, and the regulatory mechanisms of each signaling pathway are still unclear. The translation of experimental findings into clinical practice remains incomplete, necessitating further exploration through large-scale, multi-center randomized controlled trials. Given the absence of a specific drug for MIRI, the identification of therapeutic agents to reduce myocardial ischemia is of utmost significance. For the future, it is imperative to enhance our understanding of the pathological mechanism underlying MIRI, continuously investigate and develop novel pharmaceutical agents, expedite the clinical translation of these drugs, and foster innovative approaches that integrate TCM with Western medicine. These efforts will facilitate the emergence of fresh perspectives for the clinical management of MIRI.

Sulfur metabolism as a new therapeutic target of heart failure

Sulfur-based redox signaling has long attracted attention as critical mechanisms underlying the development of cardiac diseases and resultant heart failure. Especially, post-translational modifications of cysteine (Cys) thiols in proteins mediate oxidative stress-dependent cardiac remodeling including myocardial hypertrophy, senescence, and interstitial fibrosis. However, we recently revealed the existence of Cys persulfides and Cys polysulfides in cells and tissues, which show higher redox activities than Cys and substantially contribute to redox signaling and energy metabolism. We have established simple evaluation methods that can detect polysulfides in proteins and inorganic polysulfides in cells and revealed that polysulfides abundantly expressed in normal hearts are dramatically catabolized by exposure to ischemic/hypoxic and environmental electrophilic stress, which causes vulnerability of the heart to mechanical load. Accumulation of hydrogen sulfide, a nucleophilic catabolite of persulfides/polysulfides, may lead to reductive stress in ischemic hearts, and perturbation of polysulfide catabolism can improve chronic heart failure after myocardial infarction in mice. This review focuses on the (patho)physiological role of sulfur metabolism in hearts, and proposes that sulfur catabolism during ischemic/hypoxic stress has great potential as a new therapeutic strategy for the treatment of ischemic heart failure.

MAP4K4 exacerbates cardiac microvascular injury in diabetes by facilitating S-nitrosylation modification of Drp1

Dynamin-related protein 1 (Drp1) is a crucial regulator of mitochondrial dynamics, the overactivation of which can lead to cardiovascular disease. Multiple distinct posttranscriptional modifications of Drp1 have been reported, among which S-nitrosylation was recently introduced. However, the detailed regulatory mechanism of S-nitrosylation of Drp1 (SNO-Drp1) in cardiac microvascular dysfunction in diabetes remains elusive. The present study revealed that mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) was consistently upregulated in diabetic cardiomyopathy (DCM) and promoted SNO-Drp1 in cardiac microvascular endothelial cells (CMECs), which in turn led to mitochondrial dysfunction and cardiac microvascular disorder. Further studies confirmed that MAP4K4 promoted SNO-Drp1 at human C644 (mouse C650) by inhibiting glutathione peroxidase 4 (GPX4) expression, through which MAP4K4 stimulated endothelial ferroptosis in diabetes. In contrast, inhibition of MAP4K4 via DMX-5804 significantly reduced endothelial ferroptosis, alleviated cardiac microvascular dysfunction and improved cardiac dysfunction in db/db mice by reducing SNO-Drp1. In parallel, the C650A mutation in mice abolished SNO-Drp1 and the role of Drp1 in promoting cardiac microvascular disorder and cardiac dysfunction. In conclusion, our findings demonstrate that MAP4K4 plays an important role in endothelial dysfunction in DCM and reveal that SNO-Drp1 and ferroptosis activation may act as downstream targets, representing potential therapeutic targets for DCM.

Supersulfide prevents cigarette smoke extract-induced mitochondria hyperfission and cardiomyocyte early senescence by inhibiting Drp1-filamin complex formation

Smoking is one of the most serious risk factors for cardiovascular diseases. Although cigarette mainstream and sidestream smoke are significant contributors to increased cardiovascular mortality and morbidity, the underlying mechanism is still unclear. Here, we report that exposure of rat neonatal cardiomyocytes to cigarette smoke extract (CSE) induces mitochondrial hyperfission-mediated myocardial senescence. CSE leads to mitochondrial fission and reactive oxygen species (ROS) production through the complex formation between mitochondrial fission factor Drp1 and actin-binding protein, filamin A. Pharmacological perturbation of interaction between Drp1 and filamin A by cilnidipine and gene knockdown of Drp1 or filamin A inhibited CSE-induced mitochondrial hyperfission and ROS production as well as myocardial senescence. We previously reported that Drp1 activity is controlled by supersulfide-induced Cys644 polysulfidation. The redox-sensitive Cys644 was critical for CSE-mediated interaction with filamin A. The administration of supersulfide donor, Na2S3 also improved mitochondrial hyperfission-mediated myocardial senescence induced by CSE. Our results suggest the important role of Drp1-filamin A complex formation on cigarette smoke-mediated cardiac risk and the contribution of supersulfide to mitochondrial fission-associated myocardial senescence.

The Antioxidant Properties of Glucosinolates in Cardiac Cells Are Independent of H2S Signaling

The organic sulfur-containing compounds glucosinolates (GSLs) and the novel gasotransmitter H2S are known to have cardioprotective effects. This study investigated the antioxidant effects and H2S-releasing potential of three GSLs ((3E)-4-(methylsulfanyl)but-3-enyl GSL or glucoraphasatin, 4-hydroxybenzyl GSL or glucosinalbin, and (RS)-6-(methylsulfinyl)hexyl GSL or glucohesperin) in rat cardiac cells. It was found that all three GSLs had no effect on cardiac cell viability but were able to protect against H2O2-induced oxidative stress and cell death. NaHS, a H2S donor, also protected the cells from H2O2-stimulated oxidative stress and cell death. The GSLs alone or mixed with cysteine, N-acetylcysteine, glutathione, H2O2, iron and pyridoxal-5'-phosphate, or mouse liver lysates did not induce H2S release. The addition of GSLs also did not alter endogenous H2S levels in cardiac cells. H2O2 significantly induced cysteine oxidation in the cystathionine gamma-lyase (CSE) protein and inhibited the H2S production rate. In conclusion, this study found that the three tested GSLs protect cardiomyocytes from oxidative stress and cell death but independently of H2S signaling.

Cystathionine γ-lyase S-sulfhydrates SIRT1 to attenuate myocardial death in isoprenaline-induced heart failure

OBJECTIVE

Hydrogen sulfide (H₂S), the third gasotransmitter, plays a critical role in protecting against heart failure. Sirtuin-1 (SIRT1) is a highly conserved histone deacetylase that has a protective role in the treatment of heart failure by regulating the deacetylation of some functional proteins. This study investigates the interaction between SIRT1 and H₂S in heart failure and the underlying mechanisms.

METHODS AND RESULTS

Using endogenous H₂S-generating enzyme cystathionine γ-lyase (CSE) knockout mice, we found that CSE deficiency aggravated isoprenaline-induced cardiac injury. Treatment with H₂S attenuated atrial natriuretic peptide level, brain natriuretic peptide level, improved cardiac function. Moreover, H₂S treatment potentiated myocardial SIRT1 expression. Silencing CSE abolished intracellular SIRT1 expression. Furthermore, CSE/ H₂S S-sulfhydrated SIRT1 at its zinc finger domains and augmented its zinc ion binding activity to stabilize the alpha-helix structure.

DISCUSSION

In conclusion, these results uncover that a novel mechanism that CSE/H₂S S-sulfhydrated SIRT1 to prevent heart dysfunction through modulating its activity.

Sulfur signaling pathway in cardiovascular disease

Hydrogen sulfide (H2S) and sulfur dioxide (SO2), recognized as endogenous sulfur-containing gas signaling molecules, were the third and fourth molecules to be identified subsequent to nitric oxide and carbon monoxide (CO), and exerted diverse biological effects on the cardiovascular system. However, the exact mechanisms underlying the actions of H2S and SO2 have remained elusive until now. Recently, novel post-translational modifications known as S-sulfhydration and S-sulfenylation, induced by H2S and SO2 respectively, have been proposed. These modifications involve the chemical alteration of specific cysteine residues in target proteins through S-sulfhydration and S-sulfenylation, respectively. H2S induced S-sulfhydrylation can have a significant impact on various cellular processes such as cell survival, apoptosis, cell proliferation, metabolism, mitochondrial function, endoplasmic reticulum stress, vasodilation, anti-inflammatory response and oxidative stress in the cardiovascular system. Alternatively, S-sulfenylation caused by SO2 serves primarily to maintain vascular homeostasis. Additional research is warranted to explore the physiological function of proteins with specific cysteine sites, despite the considerable advancements in comprehending the role of H2S-induced S-sulfhydration and SO2-induced S-sulfenylation in the cardiovascular system. The primary objective of this review is to present a comprehensive examination of the function and potential mechanism of S-sulfhydration and S-sulfenylation in the cardiovascular system. Proteins that undergo S-sulfhydration and S-sulfenylation may serve as promising targets for therapeutic intervention and drug development in the cardiovascular system. This could potentially expedite the future development and utilization of drugs related to H2S and SO2.

Supersulfide biology and translational medicine for disease control

For decades, the major focus of redox biology has been oxygen, the most abundant element on Earth. Molecular oxygen functions as the final electron acceptor in the mitochondrial respiratory chain, contributing to energy production in aerobic organisms. In addition, oxygen-derived reactive oxygen species including hydrogen peroxide and nitrogen free radicals, such as superoxide, hydroxyl radical and nitric oxide radical, undergo a complicated sequence of electron transfer reactions with other biomolecules, which lead to their modified physiological functions and diverse biological and pathophysiological consequences (e.g. oxidative stress). What is now evident is that oxygen accounts for only a small number of redox reactions in organisms and knowledge of biological redox reactions is still quite limited. This article reviews a new aspects of redox biology which is governed by redox-active sulfur-containing molecules-supersulfides. We define the term 'supersulfides' as sulfur species with catenated sulfur atoms. Supersulfides were determined to be abundant in all organisms, but their redox biological properties have remained largely unexplored. In fact, the unique chemical properties of supersulfides permit them to be readily ionized or radicalized, thereby allowing supersulfides to actively participate in redox reactions and antioxidant responses in cells. Accumulating evidence has demonstrated that supersulfides are indispensable for fundamental biological processes such as energy production, nucleic acid metabolism, protein translation and others. Moreover, manipulation of supersulfide levels was beneficial for pathogenesis of various diseases. Thus, supersulfide biology has opened a new era of disease control that includes potential applications to clinical diagnosis, prevention and therapeutics of diseases.

Hydrogen Sulfide: An Emerging Regulator of Oxidative Stress and Cellular Homeostasis-A Comprehensive One-Year Review

Hydrogen sulfide (H2S), traditionally recognized as a toxic gas, has emerged as a critical regulator in many biological processes, including oxidative stress and cellular homeostasis. This review presents an exhaustive overview of the current understanding of H2S and its multifaceted role in mammalian cellular functioning and oxidative stress management. We delve into the biological sources and function of H2S, mechanisms underlying oxidative stress and cellular homeostasis, and the intricate relationships between these processes. We explore evidence from recent experimental and clinical studies, unraveling the intricate biochemical and molecular mechanisms dictating H2S's roles in modulating oxidative stress responses and maintaining cellular homeostasis. The clinical implications and therapeutic potential of H2S in conditions characterized by oxidative stress dysregulation and disrupted homeostasis are discussed, highlighting the emerging significance of H2S in health and disease. Finally, this review underscores current challenges, controversies, and future directions in the field, emphasizing the need for further research to harness H2S's potential as a therapeutic agent for diseases associated with oxidative stress and homeostatic imbalance. Through this review, we aim to emphasize H2S's pivotal role in cellular function, encouraging further exploration into this burgeoning area of research.

Application and value of hydrogen sulfide modulated autophagy in sepsis

Sepsis is is anabnormalhost immune responsecausedbyinfection. Antibiotics, anti-viral drugs, and vasoactive drugs have always been used in the traditional treatment of sepsis, but there are no specific and effective drugs in clinical practice. Autophagy is a highly conservative process in biological evolution, and plays an important role in maintaining intracellular homeostasis and cellular self-renewal. Autophagy can remove and degrade misfolding proteins and damaged organelles in cells, providing materials for cell repair and self-renewal. Hydrogen sulfide (H2S) is a colorless gas that smells likerotteneggs. It is the third endogenous gas signal molecule discovered after nitric oxide and carbon monoxide and has become a research hotspot in recent years. H2S has a variety of biological functions and plays an important role in various physiological and pathological processes. Thereisgrowingevidencethat H2S can regulate autophagy. The intervention of autophagy is a promising therapeutic strategy to improve sepsis organ damage. This article reviews the organ protection of autophagy in sepsis and the role of H2S in regulating autophagy in sepsis, revealing that H2S intervention with autophagy may be a a worthy target in sepsis treatment.

H2S- and Redox-State-Mediated PTP1B S-Sulfhydration in Insulin Signaling

Because hydrogen sulfide (H₂S) is classified as a gaseous signaling molecule, protein S-sulfhydration is known to be one of the mechanisms by which H₂S signals are conducted. PTP1B, a negative regulator in insulin signaling, has been found to be S-sulfhydrated at Cys215-SH to form Cys215-SSH in response to endoplasmic reticulum (ER) stress. Therefore, we aimed to understand the change in PTP1B S-sulfhydration and cellular redox homeostasis in response to insulin stimulation. We demonstrated a feasible PEG-switch method to determine the levels of PTP1B S-sulfhydration. According to the results obtained from HEK293T and MDA-MB-231 cells, insulin induced a change in PTP1B S-sulfhydration that was similar to the change in Insulin receptor substrate 1 (IRS1) phosphorylation in both cell lines. However, insulin-induced PTP1B S-sulfhydration and IRS1 phosphorylation were only significantly affected by metformin in HEK293T cells. Insulin also induced an increase in reactive oxygen species (ROS) in both cell lines. However, the level of H₂S, GSH, and GSSG was only significantly affected by insulin and metformin in HEK293T cells. HEK293T cells maintained high levels of H₂S and cysteine, but low levels of GSSG and GSH in general compared to MDA-MB-231 cells. From these findings, we suggest that PTP1B activity is modulated by H₂S and redox-regulated S-sulfhydration during insulin signaling.