Exogenous H2S Research Articles

A highly selective and sensitive fluorescence probe based on BODIPY-cyclen for hydrogen sulfide detection in living cells and serum

Hydrogen sulfide (H2S) is a multifunctional gaseous signaling molecule that plays a vital role in several biological processes. In the present study, a BODIPY-based fluorescent probe called 8-[4-((1,4,7,10-tetraazacyclododecane)methyl)phenyl]-4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a, 4a-diaza-s-indacene (BA–Cyclen)–Cu was designed and synthesized; this probe is a Cu(Ⅱ) complex that uses Cu(Ⅱ) decomplexation to achieve the sensitive and rapid detection of aqueous H2S via the “turn-on” mode. We observed that BA–Cyclen–Cu exhibited good membrane permeability, low toxicity, and lysosome-targeting ability, facilitating H2S detection in living cells. Furthermore, we demonstrated the potential biological applications of the probe by measuring exogenous H2S originating from Na2S and GYY4137, a slow-release donor, and endogenous H2S generated via the catalysis of cystathionine-β-synthase in both normal (H9c2) and cancerous (U87) cells. Moreover, BA–Cyclen–Cu was successfully used to detect exogenous H2S by the external standard method in fetal bovine serum, the serum of a healthy person, and the serum of a patient with liver cancer.

Exogenous hydrogen sulphide alleviates senescence of postharvest pakchoi through regulating antioxidant system, endogenous hydrogen sulphide and nitric oxide metabolism

Previous studies showed that hydrogen sulphide (H2S) fumigation retarded the yellowing of detached pakchoi leaves. However, whether H2S regulated specific metabolic pathways and gene expression levels in this process remained unclear. In this study, the effect of H2S, DL-propargylglycine (PAG, H2S synthetic inhibitor) on antioxidant capacity, endogenous H2S synthesis, and endogenous NO synthesis in pakchoi was investigated. After H2S fumigation (40 L L−1, 6 h), the pakchoi stored at 20 °C ± 1 °C with 90–95% relative humidity exhibited the best quality, with the highest chlorophyll content and the lowest respiration rate and malondialdehyde content. Contrarily, PAG accelerated pakchoi senescence. H2S treatment reduced superoxide anion and hydrogen peroxide by increasing the activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase, partially up-regulating the expression of enzyme genes. The increased expression of BcLCD, BcDCD and BcCAS C1 activated L- and D-cysteine desulfhydrase activities so that more endogenous H2S were retained in the pakchoi. Meanwhile, H2S treatment increased cysteine content in pakchoi via up-regulating BcSAT5 expression and enhancing the activities of sulfite reductase and serine acetyltransferase. Moreover, H2S increased endogenous NO primarily by preserving the activities of nitrate reductase and nitrite reductase instead of NO synthase (NOS)-like activity and decreased nitrate and nitrite as well. Overall, exogenous H2S alleviated the senescence of postharvest pakchoi via positively regulating antioxidant system, endogenous H2S and NO metabolism. Moreover, this work described a putative regulatory mechanism and provided some relevant information for future research into the interaction of H2S and NO in this process.

Hydrogen sulfide retards fruit softening and prevents flesh browning in cold-stored peaches by regulating cell wall-modifying enzymes, phenolic, and proline metabolism

Utilizing transcriptome analysis, higher expression of genes encoding hydrogen sulfide (H2S) synthetase in fruit stored at 0 ℃, where the expression pattern of differentially expressed genes (DEGs) correlated with softening and phenolic synthesis demonstrated more alterations than fruit storage at 5 ℃ and 15 ℃. Further research into how exogenous H2S affected the unappealing swift softening and internal browning (IB) of fruit was investigated. H2S orchestrated the cell wall-modifying enzymes, inhibiting polygalacturonase, cellulase, β-glucosidase, and pectin methyl esterase, and incompletely suppressing α/β-galactosidase and α-mannosidase during later storage. In H2S-treated fruit, total phenolic content was higher and IB symptoms were alleviated. In addition to enhancing phenylpropanoid metabolism, correlation analysis supported the hypothesis that H2S promoted phenolics in fruit by possibly facilitating proline accumulation. Cys192 and Cys217 of PpMYB75, which are involved in the biosynthesis of anthocyanin, were potential targets for persulfidation, and application of H2S reduced anthocyanin content in peach fruit. Together, our results demonstrate that H2S could ameliorate the chilling injury of cold-stored peach fruit and provide a perspective for controlling phenolic synthesis.

Gaseous signaling molecule H2S as a multitasking signal molecule in ROS metabolism of Oryza sativa under thiocyanate (SCN−) pollution

The induction of disruption in the electronic transport chain by thiocyanate (SCN−) leads to an excessive generation of reactive oxygen species (ROS) within rice (Oryza sativa). Hydrogen sulfide (H2S) assumes a crucial role as a gaseous signaling molecule, holding significant potential in alleviating SCN−-related stress. Nevertheless, there remains a dearth of understanding regarding the intricate interplay between H2S and ROS in Oryza sativa amidst SCN− pollution. In this investigation, a hydroponics-based experiment was meticulously devised to explore how H2S-mediated modifications influence the genetic feedback network governing ROS metabolism within the subcellular organelles of Oryza sativa when exposed to varying effective concentrations (EC20: 24 mg SCN/L; EC50: 96 mg SCN/L; EC75: 300 mg SCN/L) of SCN−. The findings unveiled the enhanced capacity of Oryza sativa to uptake SCN− under H2S + SCN− treatments in comparison to SCN− treatments alone. Notably, the relative growth rate (RGR) of seedlings subjected to H2S + SCN− exhibited a superior performance when contrasted with seedlings exposed solely to SCN−. Furthermore, the application of exogenous H2S yielded a significant reduction in ROS levels within Oryza sativa tissues during SCN− exposure. To elucidate the intricacies of gene regulation governing ROS metabolism at the mRNA level, the 52 targeted genes were categorized into four distinct types, namely: initial regulatory ROS generation genes (ROS-I), direct ROS scavenging genes (ROS-II), indirect ROS scavenging genes (ROS-III), and lipid oxidation genes (ROS-IV). On the whole, exogenous H2S exhibited the capacity to activate the majority of ROS-I ∼ ROS-IV genes within both Oryza sativa tissues at the EC20 concentration of SCN−. However, genetic positive/negative feedback networks emphasized the pivotal role of ROS-II genes in governing ROS metabolism within Oryza sativa. Notably, these genes were predominantly activated within the cytoplasm, chloroplasts, mitochondria, peroxisomes, and the cell wall.

Exogenous H2S initiating Nrf2/GPx4/GSH pathway through promoting Syvn1-Keap1 interaction in diabetic hearts

Excessive ROS accumulation contributes to cardiac injury in type 2 diabetes mellitus. Hydrogen sulfide (H2S) is a vital endogenous gasotransmitter to alleviate cardiac damage in diabetic cardiomyopathy (DCM). However, the underlying mechanisms remain unclear. In this study, we investigated the effects of NaHS administration in db/db mice via intraperitoneal injection for 20 weeks and the treatment of high glucose (HG), palmitate (PA) and NaHS in HL-1 cardiomyocytes for 48 h, respectively. H2S levels were decreased in hearts of db/db mice and HL-1 cardiomyocytes exposed to HG and PA, which were restored by NaHS. Exogenous H2S activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/glutathione (GSH) pathway, suppressed ferroptosis and mitigated mitochondrial apoptosis in db/db mice. However, these effects were abrogated after Nrf2 knockdown. NaHS treatment elevated the ubiquitination level of Kelch-like ECH-associated protein (Keap1) by preserving its E3 ligase synoviolin (Syvn1), resulting in Nrf2 nuclear translocation. H2S facilitated the sulfhydration of Syvn1-cys115 site, a post-translational modification. Transfecting Syvn1 C115A in cardiomyocytes exposed to HG and PA partially attenuated the effects of NaHS on Nrf2 and cell death. Our findings suggest that exogenous H2S regulates Nrf2/GPx4/GSH pathway by promoting the Syvn1-Keap1 interaction to reduce ferroptosis and mitochondrial apoptosis in DCM.

An efficient dual-function fluorescent probe for sulfites and sulfides and its imaging application in cells

As gas signaling molecules in organisms, SO2 derivatives and H2S play crucial regulating roles in a series of physiological processes. Therefore, developing an assay that can accurately monitor the concentration of SO2 derivatives and H2S in cells is extremely important for the research and treatment of related illnesses. A bifunctional probe SN-F based on FRET mechanism for SO2 derivatives and H2S was designed. SN-F had a short response time to SO2 (2 min), excellent anti-interference capability and selectivity in the non-organic solvent system (pH = 7.4), which was suitable for the determination of SO2 derivatives in cells. SN-F had a wide linear range for H2S. Moreover, SN-F was applied in cell imaging successfully with high targeting ability to endoplasmic reticulum (ER) and could monitor endogenous and exogenous H2S in cells.

A near infrared fluorescence probe with dual-site for hydrogen sulfide and sulfur dioxide detection

Both hydrogen sulfide (H2S) and sulfur dioxide (SO2) are regarded as double-edged swords. They are toxic gases at high concentration, and at low concentration they are beneficial to the human. Therefore, it is of great significance to develop single chemosensor which enable to detect them with different fluorescence signal changes. In this work, a novel dual-site fluorescence probe (AMN-SSPy) with near infrared emission (675 nm) was designed, which realized quantitative detection for H2S and SO2 by fluorescence enhancement and fluorescence quenching, respectively. AMN-SSPy showed advantages such as excellent selectivity to H2S and SO2, strong anti-interference ability, high sensitivity for H2S (LOD 1.03 µM for H2S and 77.08 µM for SO2) and low toxicity. In addition, AMN-SSPy possessed the capacity to successfully image the endogenous and exogenous H2S, and it was also used to demonstrate that Ca2+ could induce accumulation of H2S in cell and zebrafish. Finally, the rapid detection of SO2 by AMN-SSPy in real samples was also established.

THU263 Intestinal Production of H2S And Its Regulation Of GLP-2

Abstract Disclosure: J. Hammond: None. G. Yang: None. J. Gagnon: None. Background: Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter that regulates a variety of physiological processes including hormone regulation. In individuals with Crohn’s disease or colitis, H2S is elevated. Whether this H2S plays a role in gut disease development or protection is not clear. Glucagon-Like Peptide-2 (GLP-2) is a gut health-promoting peptide hormone produced in the enteroendocrine L-cells located primarily in the distal GI tract. In the gut, GLP-2 increases cell proliferation, enhances barrier function, and decreases inflammation. Furthermore, GLP-2 administration has been shown to be protective in both Crohn’s and Colitis. Finally, our previous work has shown a role for H2S in the regulation of glucagon-like peptides. Hypothesis: We hypothesize that local H2S production in the distal GI tract and in enteroendocrine cells can regulate GLP-2 secretion and downstream gut physiology.Methods: GLP-2 secretion and gut physiology were examined in mice receiving exogenous H2S injections or lacking the H2S-producing enzyme cystathionine gamma-lyase (CSE). Additionally, H2S production and GLP-2 secretion were examined from mouse enteroendocrine L-cells (GLUTag). Results: CSE KO mice had significantly reduced intestinal H2S production. A slight increase in circulating GLP-2 was found in CSE KO mice. H2S was also produced directly from enteroendocrine cells which was partially blocked using CSE enzyme inhibitors. When enteroendocrine L-cells were treated with H2S donors (NaHS and GYY 4137), GLP-2 secretion was significantly reduced (with no effect on cell viability). Ongoing work will explore the direct effects of H2S administration in mice on circulating GLP-2, and any changes that occur in the gut epithelium as a result. Discussion/Conclusions: Our work indicates that the enteroendocrine cell can produce the gasotransmitter H2S, and that H2S donors can suppress GLP-2 secretion. These findings suggest that GLP-2 may play a role in the interplay between H2S and gastric health. These results could provide support for the potential use of H2S drugs in the treatment of GI diseases. Presentation: Thursday, June 15, 2023

Hidrojen Sülfür hiperglisemik koşullar altında fibroblastlarda reaktif oksijen türevlerini azaltarak yara iyileşmesini destekler

Abstract
 
 Chronic wounds are one of the common and serious diabetic complications that also impose a significant financial burden on society. A comprehensive treatment for chronic wounds has not yet been found and new treatment recommendations are needed. The beneficial effects of hydrogen sulfide (H2S) on wound healing have previously been demonstrated in healthy or diabetic animal models. H2S has also been found to accelerate wound closure in cells and animal models. H2S has been shown to be beneficial in diabetic wound healing, but their effect on wound healing under diabetic conditions has not yet been elucidated. In this study; we investigated the effects of H2S and reactive oxygen species (ROS) on wound healing in fibroblast under high glucose conditions. We used 2,3-bis-(2-methoxy- -nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and scratch migration assay to investigate fibroblast cell viability and wound healing migration. We showed that H2S enhanced wound healing in fibroblasts incubated with high glucose by increasing cell viability, proliferation, migration and attenuating ROS. According to our results, exogenous H2S reduced oxidative stress during wound repair. In conclusion, H2S accelerated wound healing, which may be related to the inhibition of oxidative stress.

Nanomotor-based H2S donor with mitochondrial targeting function for treatment of Parkinson's disease

Reduction of endogenous hydrogen sulfide (H2S) is considered to have an important impact on the progress of Parkinson's disease (PD), thus exogenous H2S supplementation is expected to become one of the key means to treat PD. However, at present, it is difficult for H2S donors to effectively penetrate the blood brain barrier (BBB), selectively release H2S in brain, and effectively target the mitochondria of neuron cells. Herein, we report a kind of nanomotor-based H2S donor, which is obtained by free radical polymerization reaction between l-cysteine derivative modified-polyethylene glycol (PEG-Cys) and 2-methacryloyloxyethyl phosphorylcholine (MPC). This kind of H2S donor can not only effectively break through BBB, but also be specifically catalyzed by cystathionine β-synthase (CBS) in neurons of PD site in brain and 3-mercaptopyruvate sulfurtransferase (3-MST) in mitochondria to produce H2S, endowing it with chemotaxis/motion ability. Moreover, the unique chemotaxis effect of nanomotor can realize the purpose of precisely targeting brain and the mitochondria of damaged neuron cytopathic diseases. This kind of nanomotor-based H2S donor is expected to enrich the current types of H2S donors and provide new ideas for the treatment of PD.

A 3,5-dinitropyridin-2yl Substituted Flavonol-based Fluorescent Probe for Rapid Detection of H2S in Water, Foodstuff Samples and Living Cells.

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H2S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4min), large Stokes shift (138nm), and low detection limit (1.357 µM). Upon exposure to H2S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542nm. Meanwhile, the recognizing site of H2S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H2S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H2S in water samples, and it can be fabricated into fluorescent strips to track H2S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H2S in living cells. These results provide a reliable method and idea for H2S detection in complex environments.

Effects of hydrogen sulfide on relaxation responses in the lower esophageal sphincter in rabbits: the potential role of potassium channels.

Hydrogen sulfide (H2S) is a significant physiologic inhibitory neurotransmitter. The main goal of this research was to examine the contribution of diverse potassium (K+) channels and nitric oxide (NO) in mediating the H2S effect on electrical field stimulation (EFS)-induced neurogenic contractile responses in the lower esophageal sphincter (LES). EFS-induced contractile responses of rabbit isolated LES strips were recorded using force transducers in organ baths that contain Krebs-Henseleit solutions (20ml). Cumulative doses of NaHS, L-cysteine, PAG, and AOAA were evaluated in NO-dependent and NO-independent groups. The experiments were conducted again in the presence of K+ channel blockers. In both NO-dependent and NO-independent groups, NaHS, L-cysteine, PAG, and AOAA significantly reduced EFS-induced contractile responses. In the NO-dependent group, the effect of NaHS and L-cysteine decreased in the presence of 4-AP, and also the effect of NaHS decreased in the NO-dependent and independent group in the presence of TEA. In the NO-independent group, K+ channel blockers didn't change L-cysteine-induced relaxations. K+ channel blockers had no impact on the effects of PAG and AOAA. In addition, NaHS significantly relaxed 80-mM KCl-induced contractions, whereas L-cysteine, PAG, and AOAA did not. In the present study, H2S decreased the amplitudes of EFS-induced contraction responses. These results suggest that Kv channels and NO significantly contribute to exogenous H2S and endogenous H2S precursor L-cysteine inhibitory effect on lower esophageal sphincter smooth muscle.

Physiological response and molecular regulatory mechanism reveal a positive role of nitric oxide and hydrogen sulfide applications in salt tolerance of Cyclocarya paliurus.

As a multifunctional tree species, Cyclocarya paliurus leaves are rich in bioactive substances with precious healthy values. To meet the huge requirement of C. paliurus leaf production, sites with some environmental stresses would be potential land for developing its plantations due to the limitation of land resources in China. Nitric oxide (NO) and hydrogen sulfide (H2S) are common gas messengers used to alleviate abiotic stress damage, whereas the mechanism of these messengers in regulating salt resistance of C. paliurus still remains unclear. We performed a comprehensive study to reveal the physiological response and molecular regulatory mechanism of C. paliurus seedlings to the application of exogenous NO and H2S under salt stress. The results showed that the application of sodium hydrosulfide (NaHS) and sodium nitroprusside (SNP) not only maintained the photosynthetic capacity and reduced the loss of leaf biomass, but also promoted endogenous NO synthesis and reduced oxidative damage by activating antioxidant enzyme activity and increasing the content of soluble protein and flavonoids. Moreover, transcriptome and metabolome analysis indicated the expression of genes encoding phenylalanine ammonia lyase (PAL), cytochromeP450 (CYP), chalcone synthase (CHS), dihydroflavonol 4-reductase (DFR) and flavonol synthase (FLS) in flavonoid biosynthesis pathway was all up-regulated by the application of NO and H2S. Meanwhile, 15 transcriptional factors (TFs) such as WRKY, ERF, bHLH and HY5 induced by NO were found to regulated the activities of several key enzymes in flavonoid biosynthesis pathway under salt stress, via the constructed co-expression network. Our findings revealed the underlying mechanism of NO and H2S to alleviate salt stress and regulate flavonoid biosynthesis, which provides a theoretical basis for establishing C. paliurus plantations in the salt stress areas.

The therapeutic potential for targeting CSE/H2S signaling in macrophages against Escherichia coli infection

Macrophages play a pivotal role in the inflammatory response to the zoonotic pathogen E. coli, responsible for causing enteric infections. While considerable research has been conducted to comprehend the pathogenesis of this disease, scant attention devoted to host-derived H2S. Herein, we reported that E. coli infection enhanced the expression of CSE in macrophages, accompanied by a significantly increased inflammatory response. This process may be mediated by the involvement of excessive autophagy. Inhibition of AMPK or autophagy with pharmacological inhibitors could alleviate the inflammation. Additionally, cell model showed that the mRNA expression of classic inflammatory factors (Il-1β, Il-6), macrophage polarization markers (iNOS, Arg1) and ROS production was significantly down-regulated after employing CSE specific inhibitor PAG. And PAG is capable of inhibiting excessive autophagy through the LKB1-AMPK-ULK1 axis. Interestingly, exogenous H2S could suppress inflammation response. Our study emphasizes the importance of CSE in regulating the macrophage-mediated response to E. coli. Increased CSE in macrophages leads to excessive inflammation, which should be considered a new target for drug development to treat intestinal infection.

A UV-triggered water-soluble H2S donor for visual delivery of H2S in organisms and its application in plant protection

Hydrogen sulfide (H2S) serves as an important signaling molecule with important physiological functions in living organisms. Despite the current achievements in developing H2S donors, the development of controllable donors and visualization of H2S delivery within cells remains a challenge. In this paper, a new UV-light triggered H2S donor (UV-HS) was developed based on thiocarbamate. UV-HS triggered by UV light is accompanied by the release of carbonyl sulfur (COS) along with the release of compounds with fluorescence, which well aids in the visual delivery of H2S by the donor in the organism. The donor has high selectivity, high sensitivity and low cytotoxicity, enabling visual delivery of H2S within cells and zebrafish. In addition, UV-HS showed good resistance to heavy metal ion stress in arabidopsis. The present work provides new ideas for exogenous H2S supplementation in organisms and contributes to the in-depth study of H2S donors in organisms.

A steric control specific probe for visualizing drug induced fluctuations of enzymatic H2S generation in living cells

Hydrogen sulfide (H2S) is an important gas transmitter in living system, and is of great significance in many pathological and physiological processes. It is an attractive challenge to specific detect H2S due to its lower level in cell plasma compared to other three mercaptan compounds (cysteine, homocysteine, and glutathione). The hydroxylated dye DCI-Br, with ortho-site substituted by bromine atoms, exhibited highly activated near infrared fluorescence at pH 7.4, and was selected for constructing the “recognition group hidden” probe DCI-Br-NBD. Owing to the spatial protection effect, the probe showed specific response to H2S over three large volume biothiols, with good linear detection range of 0–50 μM and detection limit of 0.4 μM. Moreover, the probe has been successfully applied for visualizing exogenous H2S, and fluctuation process of H2S enzymatic generation caused by enzyme activator and inhibitor. The present strategy of adjusting the probe structure by steric hindrance, may provide guidance for the highly selective recognition of specific analyte in complex systems.

Exogenous hydrogen sulfide improves salt stress tolerance of Reaumuria soongorica seedlings by regulating active oxygen metabolism.

Hydrogen sulfide (H2S), as an endogenous gas signaling molecule, plays an important role in plant growth regulation and resistance to abiotic stress. This study aims to investigate the mechanism of exogenous H2S on the growth and development of Reaumuria soongorica seedlings under salt stress and to determine the optimal concentration for foliar application. To investigate the regulatory effects of exogenous H2S (donor sodium hydrosulfide, NaHS) at concentrations ranging from 0 to 1 mM on reactive oxygen species (ROS), antioxidant system, and osmoregulation in R. soongorica seedlings under 300 mM NaCl stress. The growth of R. soongorica seedlings was inhibited by salt stress, which resulted in a decrease in the leaf relative water content (LRWC), specific leaf area (SLA), and soluble sugar content in leaves, elevated activity levels of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT); and accumulated superoxide anion (O2-), proline, malondialdehyde (MDA), and soluble protein content in leaves; and increased L-cysteine desulfhydrase (LCD) activity and endogenous H2S content. This indicated that a high level of ROS was produced in the leaves ofR. soongoricaseedlings and seriously affected the growth and development of R. soongorica seedlings. The exogenous application of different concentrations of NaHS reduced the content of O 2-, proline and MDA, increased the activity of antioxidant enzymes and the content of osmoregulators (soluble sugars and soluble proteins), while the LCD enzyme activity and the content of endogenous H2S were further increased with the continuous application of exogenous H2S. The inhibitory effects of salt stress on the growth rate of plant height and ground diameter, the LRWC, biomass, and SLA were effectively alleviated. A comprehensive analysis showed that the LRWC, POD, and proline could be used as the main indicators to evaluate the alleviating effect of exogenous H2S on R. soongorica seedlings under salt stress. The optimal concentration of exogenous H2S for R. soongorica seedlings under salt stress was 0.025 mM. This study provides an important theoretical foundation for understanding the salt tolerance mechanism of R. soongorica and for cultivating high-quality germplasm resources.

Bioactive Vanadium Disulfide Nanostructure with "Dual" Antitumor Effects of Vanadate and Gas for Immune-Checkpoint Blockade-Enhanced Cancer Immunotherapy.

Bioactive inorganic nanomaterials and the biological effects of metal ions have attracted extensive attention in tumor therapy in recent years. Vanadium (V), as a typical bioactive metal element, regulates a variety of biological functions. However, its role in antitumor therapy remains to be revealed. Herein, biodegradable vanadium disulfide (VS2) nanosheets (NSs) were prepared as a responsive gas donor and bioactive V source for activating cancer immunotherapy in combination with immune-checkpoint blockade therapy. After PEGylation, VS2-PEG exhibited efficient glutathione (GSH) depletion and GSH-activated hydrogen sulfide (H2S) release. Exogenous H2S caused lysosome escape and reduced adenosine triphosphate (ATP) synthesis in tumor cells by interfering with the mitochondrial membrane potential and inducing acidosis. In addition, VS2-PEG degraded into high-valent vanadate, leading to Na+/K+ ATPase inhibition, potassium efflux, and interleukin (IL)-1β production. Together with further induction of ferroptosis and immunogenic cell death, a strong antitumor immune response was stimulated by reversing the immunosuppressive tumor microenvironment. Moreover, the combined treatment of VS2-PEG and α-PD-1 amplified antitumor therapy, significantly suppressed tumor growth, and further elicited robust immunity to effectively defeat tumors. This work highlights the biological effects of vanadium for application in cancer treatment.

Mapping Pregnancy-dependent Sulfhydrome Unfolds Diverse Functions of Protein Sulfhydration in Human Uterine Artery.

Uterine artery (UA) hydrogen sulfide (H2S) production is augmented in pregnancy and, on stimulation by systemic/local vasodilators, contributes to pregnancy-dependent uterine vasodilation; however, how H2S exploits this role is largely unknown. S-sulfhydration converts free thiols to persulfides at reactive cysteine(s) on targeted proteins to affect the entire proteome posttranslationally, representing the main route for H2S to elicit its function. Here, we used Tag-Switch to quantify changes in sulfhydrated (SSH-) proteins (ie, sulfhydrome) in H2S-treated nonpregnant and pregnant human UA. We further used the low-pH quantitative thiol reactivity profiling platform by which paired sulfhydromes were subjected to liquid chromatography tandem mass spectrometry-based peptide sequencing to generate site (cysteine)-specific pregnancy-dependent H2S-responsive human UA sulfhydrome. Total levels of sulfhydrated proteins were significantly greater in pregnant vs nonpregnant human UA and further stimulated by treatment with sodium hydrosulfide. We identified a total of 360 and 1671 SSH-peptides from 480 and 1186 SSH-proteins in untreated and sodium hydrosulfide-treated human UA, respectively. Bioinformatics analyses identified pregnancy-dependent H2S-responsive human UA SSH peptides/proteins, which were categorized to various molecular functions, pathways, and biological processes, especially vascular smooth muscle contraction/relaxation. Pregnancy-dependent changes in these proteins were rectified by immunoblotting of the Tag-Switch labeled SSH proteins. Low-pH quantitative thiol reactivity profiling failed to identify low abundance SSH proteins such as KATP channels in human UA; however, immunoblotting of Tag-Switch-labeled SSH proteins identified pregnancy-dependent upregulation of SSH-KATP channels without altering their total proteins. Thus, comprehensive analyses of human UA sulfhydromes influenced by endogenous and exogenous H2S inform novel roles of protein sulfhydration in uterine hemodynamics regulation.

Screening of H2S donors with a red emission mitochondria-targetable fluorescent probe: Toward discovering a new therapeutic strategy for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder caused by various factors such as neuroinflammation, oxidative stress, mitochondrial dysfunction, and neuronal apoptosis. Recent studies have shown that H2S supplementation reverses neuronal loss and mitigates motor deficits in PD patients through anti-inflammatory, antioxidant, improved mitochondrial function and proautophagic. Therefore, the discovery and use of H2S donors may be an exciting and intriguing strategy for the treatment of PD. Herein, we report a red emission mitochondria-targetable fluorescent probe, Rho-H2S, which can specifically and sensitively detect H2S with a limit of detection of 62.5 nM. Bioimaging experiments have shown that the probe has excellent mitochondrial targeting and good imaging capabilities for the detection of exogenous and endogenous H2S in cells. More importantly, based on the Rho-H2S probe, we first confirmed the sulforaphane (SFN) among 15 glucosinolate and isothiocyanate compounds from cruciferous vegetables with an outstanding ability to release H2S and we further proved that SFN could alleviate the symptoms of PD in vivo. All results demonstrate that Rho-H2S could be an effective tool for screening H2S donors and can contribute to the development of new therapeutic strategies for PD.