Hydrogen Sulfide Donor Research Articles

Hydrogen Sulfide Protects against Rat Ischemic Brain Injury by Promoting RhoA Phosphorylation at Serine 188.

The protective role of hydrogen sulfide against cerebral ischemia-reperfusion injury involves the inhibition of the RhoA-/Rho-associated coiled-coil kinase (ROCK) pathway. However, the specific mechanism remains elusive. This study investigates the impact of hydrogen sulfide on RhoA phosphorylation at serine 188 (Ser188) in vivo, aiming to test the hypothesis that hydrogen sulfide exerts neuroprotection by enhancing RhoA phosphorylation at Ser188, subsequently inhibiting the RhoA/ROCK pathway. Recombinant RhoAwild-pEGFP-N1 and RhoAS188A-pEGFP-N1 plasmids were constructed and administered via stereotaxic injection into the rat hippocampus. A rat global cerebral ischemia-reperfusion model was induced by bilateral carotid artery ligation to elucidate the neuroprotective mechanisms of hydrogen sulfide. Both RhoAwild-pEGFP-N1 and RhoAS188A-pEGFP-N1 plasmids expressed RhoAwild and RhoAS188A proteins, respectively, in rat hippocampal tissues, alongside the intrinsic RhoA protein. Systemic administration of the exogenous hydrogen sulfide donor sodium hydrosulfide led to an increase in Ser188 phosphorylation of transfected RhoAwild and intrinsic RhoA protein within the hippocampus. However, this effect was not observed in tissues transfected with RhoAS188A. Sodium hydrosulfide-mediated RhoA phosphorylation correlated with decreased RhoA and ROCK2 activity in rat hippocampal tissues. Furthermore, sodium hydrosulfide administration reduced cerebral ischemia-reperfusion-induced neuronal damage and apoptosis in rat hippocampal tissues transfected with RhoAwild. However, this neuroprotective effect was attenuated in rats transfected with RhoAS188A. These findings suggest that the neuroprotective mechanism of hydrogen sulfide against cerebral ischemia/reperfusion injury involves increased RhoA phosphorylation at Ser188. Promoting this phosphorylation may represent a potential intrinsic therapeutic target for ischemic stroke.

Priming avocado with sodium hydrosulfide prior to frost conditions induces the expression of genes involved in protection and stress responses.

Priming plants with chemical agents has been extensively investigated as a means for improving their tolerance to many biotic and abiotic stresses. Earlier, we showed that priming young avocado (Persea americana Mill cv. 'Hass') trees with sodium hydrosulfide (NaHS), a donor of hydrogen sulfide, improves the response of photosynthesis to simulated frost (cold followed by high light) conditions. In the current study, we performed a transcriptome analysis to gain insight into the molecular response of avocado 'Hass' leaves to frost, with or without NaHS priming. The analysis revealed 2144 (down-regulated) and 2064 (up-regulated) differentially expressed genes (DEGs) common to both non-primed and primed trees. Non-primed trees had 697 (down) and 559 (up) unique DEGs, while primed trees exhibited 1395 (down) and 1385 (up) unique DEGs. We focus on changes in the expression patterns of genes encoding proteins involved in photosynthesis, carbon cycle, protective functions, biosynthesis of isoprenoids and abscisic acid (ABA), as well as ABA-regulated genes. Notably, the differential expression results depict the enhanced response of primed trees to the frost and highlight gene expression changes unique to primed trees. Amongst these are up-regulated genes encoding pathogenesis-related proteins, heat shock proteins, enzymes for ABA metabolism, and ABA-induced transcription factors. Extending the priming experiments to field conditions, which showed a benefit to the physiology of trees following chilling, suggests that it can be a possible means to improve trees' response to cold stress under natural winter conditions.

Evaluating the Effects of Kidney Preservation at 10 °C with Hemopure and Sodium Thiosulfate in a Rat Model of Syngeneic Orthotopic Kidney Transplantation.

Kidney transplantation is preferred for end-stage renal disease. The current gold standard for kidney preservation is static cold storage (SCS) at 4 °C. However, SCS contributes to renal graft damage through ischemia-reperfusion injury (IRI). We previously reported renal graft protection after SCS with a hydrogen sulfide donor, sodium thiosulfate (STS), at 4 °C. Therefore, this study aims to investigate whether SCS at 10 °C with STS and Hemopure (blood substitute), will provide similar protection. Using in vitro model of IRI, we subjected rat renal proximal tubular epithelial cells to hypoxia-reoxygenation for 24 h at 10 °C with or without STS and measured cell viability. In vivo, we preserved 36 donor kidneys of Lewis rats for 24 h in a preservation solution at 10 °C supplemented with STS, Hemopure, or both followed by transplantation. Tissue damage and recipient graft function parameters, including serum creatinine, blood urea nitrogen, urine osmolality, and glomerular filtration rate (GFR), were evaluated. STS-treated proximal tubular epithelial cells exhibited enhanced viability at 10 °C compared with untreated control cells (p < 0.05). Also, STS and Hemopure improved renal graft function compared with control grafts (p < 0.05) in the early time period after the transplant, but long-term function did not reach significance. Overall, renal graft preservation at 10 °C with STS and Hemopure supplementation has the potential to enhance graft function and reduce kidney damage, suggesting a novel approach to reducing IRI and post-transplant complications.

Glycosidase-activated H2S donorsto enhance chemotherapy efficacy

Hydrogen sulfide (H2S) plays a critical role in cancer biology. Herein, we developed a series of glycosidase-triggered hydrogen sulfide (H2S) donors by connecting sugar moieties (including glucose, galactose and mannose) to COS donors via a self-immolative spacer. In the presence of corresponding glycosidases, H2S was gradually released from these donors in PBS buffer with releasing efficiencies from 36 to 67 %. H2S release was also detected by H2S probe WSP-1 after treatment HepG2 cells with Man1. Cytotoxicities of these glycosylated H2S donors were evaluated against HepG2 by MTT assay. Among them, Man1 and Man2 exhibited an obvious reduction of cell viability in HepG2 cells, with cell viability as 37.6 % for 80 μM of Man. Consistently, significant apoptosis was observed in HepG2 cells after treatment with Man1 and Man2. Finally, We evaluated the potential of Man1 for combination therapy with doxorubicin. A synergistic effect was observed between Man1 and Doxorubicin in HepG2 and Hela cells. All these results indicated glycosidase-activated H2S donorshave promising potential for cancer therapy.

Manganese Porphyrin‐Containing Polymeric Micelles: A Novel Approach for Intracellular Catalytic Formation of Per/Polysulfide Species from a Hydrogen Sulfide Donor (Adv. Healthcare Mater. 4/2024)

Manganese Porphyrin‐Containing Polymeric Micelles: A Novel Approach for Intracellular Catalytic Formation of Per/Polysulfide Species from a Hydrogen Sulfide Donor (Adv. Healthcare Mater. 4/2024)

Hydrogen sulfide reduces oxidative stress in Huntington's disease via Nrf2.

JOURNAL/nrgr/04.03/01300535-202506000-00028/figure1/v/2024-08-05T133530Z/r/image-tiff The pathophysiology of Huntington's disease involves high levels of the neurotoxin quinolinic acid. Quinolinic acid accumulation results in oxidative stress, which leads to neurotoxicity. However, the molecular and cellular mechanisms by which quinolinic acid contributes to Huntington's disease pathology remain unknown. In this study, we established in vitro and in vivo models of Huntington's disease by administering quinolinic acid to the PC12 neuronal cell line and the striatum of mice, respectively. We observed a decrease in the levels of hydrogen sulfide in both PC12 cells and mouse serum, which was accompanied by down-regulation of cystathionine β-synthase, an enzyme responsible for hydrogen sulfide production. However, treatment with NaHS (a hydrogen sulfide donor) increased hydrogen sulfide levels in the neurons and in mouse serum, as well as cystathionine β-synthase expression in the neurons and the mouse striatum, while also improving oxidative imbalance and mitochondrial dysfunction in PC12 cells and the mouse striatum. These beneficial effects correlated with upregulation of nuclear factor erythroid 2-related factor 2 expression. Finally, treatment with the nuclear factor erythroid 2-related factor 2 inhibitor ML385 reversed the beneficial impact of exogenous hydrogen sulfide on quinolinic acid-induced oxidative stress. Taken together, our findings show that hydrogen sulfide reduces oxidative stress in Huntington's disease by activating nuclear factor erythroid 2-related factor 2, suggesting that hydrogen sulfide is a novel neuroprotective drug candidate for treating patients with Huntington's disease.

Homocysteine and mitochondrial quality control in diabetic retinopathy

BackgroundDiabetic retinopathy is a progressive disease, and one of the key metabolic abnormalities in the pathogenesis of diabetic retinopathy, mitochondrial damage, is also influenced by the duration of hyperglycemia. Mitochondrial quality control involves a coordination of mitochondrial dynamics, biogenesis and removal of the damaged mitochondria. In diabetes, these processes are impaired, and the damaged mitochondria continue to produce free radicals. Diabetic patients also have high homocysteine and reduced levels of hydrogen sulfide, and hyperhomocysteinemia is shown to exacerbate diabetes-induced mitochondrial damage and worsen their dynamics. This study aims to investigate the temporal relationship between hyperhomocysteinemia and retinal mitochondrial quality control in diabetic retinopathy.MethodsHuman retinal endothelial cells incubated in 20 mM d-glucose for 24 to 96 h, in the absence or presence of 100 µM homocysteine, with/without a hydrogen sulfide donor GYY4137, were analyzed for mitochondrial ROS (MitoSox fluorescence), DNA damage (transcripts of mtDNA-encoded ND6 and CytB), copy numbers, oxygen consumption rate (Seahorse XF analyzer) and mitophagy (mitophagosomes immunofluorescence labeling and flow cytometry). Results were confirmed in the retina from mice genetically manipulated for hyperhomocysteinemia (cystathionine β-synthase deficient mice, Cbs+/−), streptozotocin-induced diabetic for 8 to 24 weeks. At 24 weeks of diabetes, vascular health was evaluated by counting acellular capillaries in the trypsin digested retinal vasculature and by fluorescein angiography.ResultsHomocysteine, in high glucose medium, exacerbated mitochondrial ROS production, mtDNA damage and impaired mitochondrial respiration within 24 h, and slowed down/worsened mitochondrial biogenesis and mitophagy, as compared to 48 to 96 h in high glucose alone. GYY4137 supplementation ameliorated homocysteine + high glucose-induced mitochondrial damage and impairment in biogenesis and mitophagy. Similar results were obtained from Cbs+/− mice-mitochondrial ROS, mtDNA damage and decline in biogenesis and mitophagy were observed within eight weeks of diabetes vs. 16 to 24 weeks of diabetes in Cbs+/+ mice, and at 24 weeks of diabetes, Cbs+/− mice had significantly higher acellular capillaries and vascular leakage.ConclusionsHyperhomocysteinemia, in a hyperglycemic environment, overwhelms the mitochondria, accelerating and exacerbating their dysfunction, and also delays/worsens their removal, augmenting the development of diabetic retinopathy. Thus, our results strengthen the importance of maintaining homocysteine-hydrogen sulfide balance during the early stages of diabetes for a patient to prevent/retard vision loss.

A slow-releasing donor of hydrogen sulfide inhibits neuronal cell death via anti-PANoptosis in rats with spinal cord ischemia‒reperfusion injury

BackgroundSpinal cord ischemia‒reperfusion injury (SCIRI) can lead to paraplegia, which leads to permanent motor function loss. It is a disastrous complication of surgery and causes tremendous socioeconomic burden. However, effective treatments for SCIRI are still lacking. PANoptosis consists of three kinds of programmed cell death, pyroptosis, apoptosis, and necroptosis, and may contribute to ischemia‒reperfusion-induced neuron death. Previous studies have demonstrated that hydrogen sulfide (H2S) exerts a neuroprotective effect in many neurodegenerative diseases. However, whether H2S is anti-PANoptosis and neuroprotective in the progression of acute SCIRI remains unclear. Thus, in this study we aimed to explore the role of H2S in SCIRI and its underlying mechanisms.MethodsMeasurements of lower limb function, neuronal activity, microglia/macrophage function histopathological examinations, and biochemical levels were performed to examine the efficacy of H2S and to further demonstrate the mechanism and treatment of SCIRI.ResultsThe results showed that GYY4137 (a slow-releasing H2S donor) treatment attenuated the loss of Nissl bodies after SCIRI and improved the BBB score. Additionally, the number of TUNEL-positive and cleaved caspase-3-positive cells was decreased, and the upregulation of expression of cleaved caspase-8, cleaved caspase-3, Bax, and Bad and downregulation of Bcl-2 expression were reversed after GYY4137 administration. Meanwhile, both the expression and activation of p-MLKL, p-RIP1, and p-RIP3, along with the number of PI-positive and RIP3-positive neurons, were decreased in GYY4137-treated rats. Furthermore, GYY4137 administration reduced the expression of NLRP3, cleaved caspase-1 and cleaved GSDMD, decreased the colocalization NeuN/NLRP3 and Iba1/interleukin-1β-expressing cells, and inhibited proinflammatory factors and microglia/macrophage polarization.ConclusionsH2S ameliorated spinal cord neuron loss, prevented motor dysfunction after SCIRI, and exerted a neuroprotective effect via the inhibition of PANoptosis and overactivated microglia-mediated neuroinflammation in SCIRI.

Hydrosulphide-methaemoglobin-albumin cluster: a hydrogen sulphide donor.

Methaemoglobin (metHb) possesses inherent characteristics that facilitate reversible binding to hydrogen sulphide. Exogenous hydrogen sulphide supplementation imparts beneficial bioactive effects, including antioxidant and anti-inflammatory; hence, we hypothesized that the metHb-hydrogen sulphide complex could act as a hydrogen sulphide donor for medication. In this study, we prepared a hydrosulphide-metHb-albumin (H2S-metHb-albumin) cluster and examined its applicability as a hydrogen sulphide donor in the mice model of hepatic ischemia-reperfusion injury. Structural analysis revealed that the H2S-metHb-albumin cluster exhibited a nanostructure wherein one metHb was wrapped by an average of three albumins, and hydrogen sulphide was bound to the haem. Additionally, the H2S-metHb-albumin cluster exhibited low-pH responsiveness, leading to sustained release of hydrogen sulphide. Owing to these structural and pharmaceutical characteristics, the severity of hepatic ischemia-reperfusion injury was alleviated via antioxidant and anti-inflammatory effects of the H2S-metHb-albumin cluster treatment. The protective effects were more potent in the H2S-metHb-albumin cluster compared to that in a conventional hydrogen sulphide donor (sodium hydrogen sulphide). No abnormal signs of toxic and biological responses were observed after the H2S-metHb-albumin cluster administration, confirming high biological compatibility. These results successfully establish the proof of concept that the H2S-metHb-albumin cluster is a promising hydrogen sulphide donor. To the best of our knowledge, this is the first report demonstrating the remarkable potential of metHb as a biomaterial for hydrogen sulphide donors.

Discovery of novel β-elemene hybrids with hydrogen sulfide-releasing moiety possessing cardiovascular protective activity for the treatment of atherosclerosis.

Herein, a series of novel β-elemene hybrids with different types of hydrogen sulfide (H2S) donors was designed and synthesized for the first time. In addition, all compounds were tested for H2S release in phosphate buffer solution assay, among which the derivatives with 5-p-hydroxyphenyl-3H-1,2-dithiole-3-thione (ADT-OH) as the H2S donor released the best level. The results of the isolated vasodilation assay revealed that all the compounds exhibited a degree of vasodilatory effect, and the representative compound "β-elemene-H2S gas donor" hybrid L13-2h produced more than 50% vasodilatory activity at a concentration of 20 μM. Furthermore, L13-2h possessed good concentration dependence and significantly better vasodilatory activity than the lead compound L13. In the RAW 264.7 cellular lipid inhibition against oxidized low-density lipoprotein (ox-LDL) stimulation assay, eight compounds, including L13-2g and L13-2h, produced significant cellular lipid-lowering activity. The results of the further antioxidant activity study showed that the representative compounds L13-2g and L13-2h improved H2O2-induced oxidative damage in HUVEC cells and compound L13-2h exhibited excellent antioxidant damage protection activity compared to the positive control. Moreover, none of the target compounds appeared to be significantly cytotoxic at the tested concentrations. These results suggest that the hybridization of hydrogen sulfide donors with β-elemene provides a promising approach for the discovery of novel anti-atherosclerotic drugs from natural products.

Protective Effect of the Exogenous Hydrogen Sulfide Donor, Parkia speciosa Hassk. against Hypertensive Nephropathy

Protective Effect of the Exogenous Hydrogen Sulfide Donor, Parkia speciosa Hassk. against Hypertensive Nephropathy

Investigation of the Effect of Hydrogen Sulfide Donor Sodium Hydrogen Sulfide on In Vitro Wound Healing

Yara iyileşmesi sürecinde büyüme faktörlerinin hücre proliferasyonu, hücre farklılaşması ve hücre ölümü gibi çeşitli biyolojik aktiviteleri mevcuttur. Gazotransmitterler yara iyileşme sürecinde etkinliği gösterilmiş sinyal molekülleridir. Gazotransmitter ailesinin bir üyesi olan H2S’in in vivo çalışmalarda yara iyileşmesinde düzenleyici bir molekül olarak görev aldığı bildirilmektedir. H2S’in yara iyileşme sürecinde çeşitli sinyal yolaklarının aktivasyonu aracılığıyla indirekt etkisinin olduğu görülmektedir. Bu çalışmada H2S’in indirekt etkisinden ziyade direkt etkisinin olup olmadığı araştırılmıştır. Bu bağlamda H2S donörü olan NaHS’in in vitro yara iyileşmesinde fonksiyon gösteren çeşitli genlerin ekspresyon düzeylerine olan etkisi değerlendirilmiştir. İmmortalize insan keratinosit hücreleri 50μg, 25μg, 10μg, 5μg, 1μg konsantrasyonda NaHS ile 24, 48 ve 72 saat boyunca inkübe edilmiş ve MTS analizi ile hücre canlığı belirlenmiştir. TGF-β1, TGF-β3, VEGF ve K17 gen ifadelerindeki değişimler qRT-PCR yöntemiyle belirlenerek elde edilen veriler ΔΔCT metodu ile hesaplanmıştır. Hücre canlılığı açısından farklı konsantrasyonlarda uygulanan NaHS’in 1μg’lık dozunun toksik olmayan doz olduğu belirlenmiştir. NaHS uygulamasının K17 mRNA ekspresyonunu anlamlı düzeyde arttırırken TGF-β1, TGF-β3 ve VEGF ekspresyonunda anlamlı değişikliğe yol açmadığı saptanmıştır. NaHS’in in vitro yara iyileşmesi üzerine direkt etkisinin olmadığı sonucuna varılmıştır.

Searching for Novel Sources of Hydrogen Sulfide Donors: Chemical Profiling of Polycarpa aurata Extract and Evaluation of the Anti-Inflammatory Effects.

Hydrogen sulfide (H2S) is a signaling molecule endogenously produced within mammals' cells that plays an important role in inflammation, exerting anti-inflammatory effects. In this view, the research has shown a growing interest in identifying natural H2S donors. Herein, for the first time, the potential of marine extract as a source of H2S-releasing agents has been explored. Different fractions obtained by the Indonesian ascidian Polycarpa aurata were evaluated for their ability to release H2S in solution. The main components of the most active fraction were then characterized by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and NMR spectroscopy. The ability of this fraction to release H2S was evaluated in a cell-free assay and J774 macrophages by a fluorimetric method, and its anti-inflammatory activity was evaluated in vitro and in vivo by using carrageenan-induced mouse paw edema. The anti-inflammatory effects were assessed by inhibiting the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and interleukin-6 (IL-6), coupled with a reduction in nitric oxide (NO) and IL-6 levels. Thus, this study defines the first example of a marine source able to inhibit inflammatory responses in vivo through the release of H2S.

Astaxanthin and meclizine extend lifespan in UM-HET3 male mice; fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate do not significantly affect lifespan in either sex at the doses and schedules used

In genetically heterogeneous (UM-HET3) mice produced by the CByB6F1 × C3D2F1 cross, the Nrf2 activator astaxanthin (Asta) extended the median male lifespan by 12% (p = 0.003, log-rank test), while meclizine (Mec), an mTORC1 inhibitor, extended the male lifespan by 8% (p = 0.03). Asta was fed at 1840 ± 520 (9) ppm and Mec at 544 ± 48 (9) ppm, stated as mean ± SE (n) of independent diet preparations. Both were started at 12 months of age. The 90th percentile lifespan for both treatments was extended in absolute value by 6% in males, but neither was significant by the Wang–Allison test. Five other new agents were also tested as follows: fisetin, SG1002 (hydrogen sulfide donor), dimethyl fumarate, mycophenolic acid, and 4-phenylbutyrate. None of these increased lifespan significantly at the dose and method of administration tested in either sex. Amounts of dimethyl fumarate in the diet averaged 35% of the target dose, which may explain the absence of lifespan effects. Body weight was not significantly affected in males by any of the test agents. Late life weights were lower in females fed Asta and Mec, but lifespan was not significantly affected in these females. The male-specific lifespan benefits from Asta and Mec may provide insights into sex-specific aspects of aging.

The Protective Action of Hsp70 and Hydrogen Sulfide Donors in THP-1 Macrophages in the Lipopolysaccharide-Induced Inflammatory Response by Modulating Endocytosis

—Hsp70 and hydrogen sulfide donors reduce inflammatory processes in human and animal cells. The biological action mediated by Hsp70 and H2S donors (GYY4137 and sodium thiosulfate) depends on their protection kinetics from cell activation by lipopolysaccharides. However, the molecular mechanisms of action of Hsp70 and H2S are not well understood. We studied the effect of human recombinant Hsp70 and H2S donors on the formation of reactive oxygen species and tumor necrosis factor-alpha induced in human cells (THP-1) by lipopolysaccharides. Transcriptomic changes occurring in these cells after LPS administration in combination with GYY4137 pretreatment were investigated. The results we obtained showed that Hsp70 and hydrogen sulfide donors reduce inflammatory processes in cells activated by the action of LPS. Hsp70 and H2S donors differed in the kinetics of the protective action, while hydrogen sulfide donors turned out to be more effective. The role of endocytosis in the mechanisms of protection of cells by H2S and Hsp70 donors from the action of LPS was studied. It has been found that GYY4137 pretreatment of LPS-exposed cells reduces the LPS-induced induction of various pro-inflammatory genes and affects the expression of genes of various intracellular signaling pathways.

The Effects of the Hydrogen Sulfide Donor GYY4137 on the Proteasome Pool of Colorectal Cancer Cells

The Effects of the Hydrogen Sulfide Donor GYY4137 on the Proteasome Pool of Colorectal Cancer Cells

Neuroprotective Effects of a Hydrogen Sulfide Donor in Streptozotocin-Induced Diabetic Rats

Diabetic neuropathy is an important long-term complication of diabetes. This study explored the hypothesis that hydrogen sulfide (H2S) ameliorates neuropathic pain by controlling antiapoptotic and pro-apoptotic processes. The effects of a slow-releasing H2S donor, GYY4137, on the expression of antiapoptotic and pro-apoptotic genes and proteins, such as B-cell lymphoma 2 (Bcl2) and Bcl-2-like protein 4 (Bax), as well as caspases, cyclooxygenase (COX)-1 and COX-2, monocytes/macrophages, and endothelial cells, in the spinal cord of male Sprague-Dawley rats with streptozotocin-induced peripheral diabetic neuropathy, were investigated using reverse transcription-PCR, western blot and immunohistochemistry. The antihypoalgesic activities of GYY4137 on diabetic rats were evaluated using the tail flick test. Treatment of diabetic rats with GYY4137 attenuated thermal hypoalgesia and prevented both the diabetes-induced increase in Bax mRNA expression (p = 0.0032) and the diabetes-induced decrease in Bcl2 mRNA expression (p = 0.028). The GYY4137-treated diabetic group had increased COX-1 (p = 0.015), decreased COX-2 (p = 0.002), reduced caspase-7 and caspase-9 protein expression (p &lt; 0.05), and lower numbers of endothelial and monocyte/macrophage cells (p &lt; 0.05) compared to the non-treated diabetic group. In summary, the current study demonstrated the protective properties of H2S, which prevented the development of neuropathy related behavior, and suppressed apoptosis activation pathways and inflammation in the spinal cord. H2S-releasing drugs could be considered as possible treatment options of diabetic peripheral neuropathy.

The Hydrogen Sulfide Donor AP39 Reduces Glutamate-mediated Excitotoxicity in a Rat Model of Brain Ischemia

The vast majority of stroke cases are classified as ischemic stroke, but effective pharmacotherapy strategies to treat brain infarction are still limited. Glutamate, which is a primary mediator of excitotoxicity, contributes to neuronal damage in numerous pathologies, including ischemia. The aim of this study was to investigate the effect of the hydrogen sulfide donor AP39 on excitotoxicity. AP39 was administered as a single dose of 100 nmol/kg b.w. i.v. 10 min after the restoration of blood flow and 100 min after middle cerebral artery occlusion (MCAO) in male Sprague-Dawley rats. Neurological deficits by Phillips’s score, and infarct volume by TTC staining were evaluated (n = 8). LC-MS was used to determine the extracellular glutamate concentration in microdialysates collected intrasurgically and from freely moving animals 24 h and 3 days after reperfusion (n = 6). The expression of proteins involved in the regulation of glutamatergic transmission was investigated 24 h after reperfusion by Western-blot analysis (n = 6). The results were verified by double-immunostaining of brain cryosections (n = 6). The results showed a significant longitudinal decrease in extracellular glutamate concentrations in the motor cortex and hippocampus in MCAO + AP39 rats compared to MCAO rats. Moreover, the administration of AP39 increased the content of the GLT-1 transporter and reduced the content of VGLUT1 in the ischemic core. Upregulation of the GLT-1 transporter responsible for glutamate reuptake from the synaptic cleft, and downregulation of VGLUT1, which regulates glutamate transport to synaptic vesicles, indicate that these are important mechanisms by which AP39 reduces extracellular glutamate concentrations and, consequently, excitotoxicity after ischemia.

Ageing-Related Alterations in Renal Epithelial Glucose Transport.

The kidney plays a crucial role in glucose homeostasis by regulating glucose transport. We aimed to investigate the impact of alterations in glucose transport on glucose metabolism during ageing. Adult male Sprague Dawley rats were divided into five groups: 3-month, 6-month, and 12-month control groups, and 6- and 12-month groups receiving the hydrogen sulfide donor molecule GYY4137. The study found that, as age increased, daily urinary uric acid and protein levels increased in the 12-month group. Blood sugar level and HOMA-IR index increased in the 12-month group, and were partially improved by GYY4137. The kidney tissue showed mild glomerulosclerosis in the 12-month group, which was diminished by GYY4137. Gene expression analysis showed decreased sirtuin and increased p21 expression in the aging groups. Increased SGLT1 and SGLT2 expression was observed in the 12-month group, which was reversed by GYY4137. Both GLUT1 and GLUT2 expression was increased in the 6- and 12-month groups, and reversed by GYY4137 in the 12-month group. The study concluded that aging was associated with increased blood sugar levels and the HOMA-IR index, and the abundance of renal glucose transporters increased as aging progressed. GYY4137 effectively reversed aging-related alterations in glucose homeostasis and renal epithelial transporters.

Manganese Porphyrin-Containing Polymeric Micelles: A Novel Approach for Intracellular Catalytic Formation of Per/Polysulfide Species from a Hydrogen Sulfide Donor.

Per/polysulfide species that are generated from endogenously produced hydrogen sulfide have critical regulatory roles in a wide range of cellular processes. However, the lack of delivery systems that enable controlled and sustained release of these unstable species in biological systems hinders the advancement of sulfide biology research, as well as the translation of knowledge to therapeutic applications. Here, a novel approach is developed to generate per/polysulfide species in cells by combining an H2 S donor and manganese porphyrin-containing polymeric micelles (MnPMCs) that catalyze oxidization of H2 S to per/polysulfide species. MnPMCs serve as a catalyst for H2 S oxidation in aerobic phosphate buffer. HPLC-MS/MS analysis reveals that H2 S oxidation by MnPMCs in the presence of glutathione results in the formation of glutathione-SnH (n = 2 and 3). Furthermore, co-treatment of human umbilical vein endothelial cells with the H2 S donor anethole dithiolethione and MnPMCs increases intracellular per/polysulfide levels and induces a proangiogenic response. Co-delivery of MnPMCs and an H2 S donor is a promising approach for controlled delivery of polysulfides for therapeutic applications.