Hydrogen sulfide in the experimental models of arterial hypertension

From methionine to sulfide: Exploring the diagnostic and therapeutic potential of sulfur-containing biomolecules in hypertension

Sulfur-containing amino acids are involved in the regulation of vascular activity and blood pressure. Clinically, a positive correlation was found between serum homocysteine levels and blood pressure. On the other hand, methionine and cysteine levels were reduced in hypertensive patients. Recently, the redox state of sulfur-containing amino acids has emerged as potential diagnostic marker of cardiovascular health. Metabolomic studies have revealed a shift in thiol/disulfide ratio toward oxidized forms and overproduction of thiyl radicals in hypertensive patients. Although accumulating evidence confirms that sulfur-containing amino acids are essential for the maintaining of redox homeostasis and blood pressure control, their hypotensive and antioxidant properties have been primarily demonstrated in animal studies. While several groups are developing new targeted and triggered sulfur-based donors, standardized pharmacological interventions for hypertensive patients are largely absent and pose a challenge for future research. In this review, we summarize recent studies that investigate the role of sulfur-containing amino acids and their redox-active metabolites, including glutathione and sulfide, in blood pressure control and the development of systemic hypertension.

Hydrogen sulfide-mediated cardiovascular protection involved in the antihypertensive effect of the saiga antelope horn

ETHNOPHARMACOLOGICAL RELEVANCE

Saiga antelope horn (SAH), derived from the male Saiga tatarica Linnaeus, has been used in China for millennia to treat hyperpyretic convulsions and hypertension-related diseases. Clarifying its effectiveness and mechanism of action are essential because of its limited availability. This study will guide the investigation of alternative resources.

AIM OF THE STUDY

The study investigated the short- and long-term antihypertensive effectiveness of SAH in spontaneously hypertensive rats (SHRs) and the relation of its mechanism of action to H2S (hydrogen sulfide), other reactive sulfur species (RSS), and the renin-angiotensin-aldosterone system (RAAS).

MATERIALS AND METHODS

In the SHR model, blood pressure was independently monitored by the tail-cuff method and carotid artery intubation. Hypertension was assessed weekly by physical signs, including facial temperature, irritability, pain, rotation time, and water consumption. The effects of SAH on the RAAS, vasoactive substances, and sympathetic neurotransmitters were measured by enzyme-linked immunosorbent assays (ELISAs) and colorimetry on study completion. Transcriptomics detected differentially expressed mRNAs and enriched signaling pathways in thoracic aorta tissue. H2S was measured in the mesenteric arteries and thoracic aorta by probe staining and PbS detection. H2S and other RSS were measured in intestinal tissue by liquid chromatography-mass spectrometry. The correlation of the antihypertensive activity of SAH with H2S was tested with DL-propargylglycine (PAG), a cystathionine-γ-lyase (CSE) inhibitor. SAH organ protection was evaluated by histopathologic staining of artery, heart, and kidney tissue.

RESULTS

SAH had significant short- and long-term effectiveness. It improved symptom scores and regulated RAAS, vasoactive substances, and sympathetic neurotransmitters. Transcriptomes of thoracic aorta tissue found differentially expressed genes following SAH treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment found that those genes were enriched in calcium, oxidative phosphorylation, and aldosterone-regulated sodium reabsorption and were involved in the regulation of the biosynthesis and metabolism of sulfur compounds and thioesters. SAH significantly increased H2S levels in arterial and intestinal tissue, and its antihypertensive activity was abolished by PAG treatment. SAH improved lesions and reduced collagen deposition in the kidneys, heart, and arteries in SHRs.

CONCLUSION

SAH had significant antihypertensive activity and protected against organ damage by regulating the metabolism of H2S and other active sulfur and reactive oxygen species.

Exogenous hydrogen sulfide improves non-alcoholic fatty liver disease by inhibiting endoplasmic reticulum stress/NLRP3 inflammasome pathway

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease worldwide, and its exact pathogenesis has not been fully studied. Hydrogen sulfide (H2S) is the third gas signaling molecule discovered in mammals, following nitric oxide and carbon monoxide. It has the effects of anti-inflammation, anti-apoptosis, and so on, thereby playing an important role in many diseases. However, the role and mechanism of exogenous H2S in NAFLD are not fully understood. In this study, we constructed in vitro and in vivo NAFLD models by feeding mice a high-fat diet and stimulating hepatocytes with palmitic acid, respectively, to investigate the improvement effect and mechanism of exogenous H2S on NAFLD. The results showed that NaHS (a donor of H2S) treatment alleviated lipid accumulation, inflammation, apoptosis and pyroptosis, and downregulated endoplasmic reticulum (ER) stress and nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NRRP3) inflammasome in NAFLD. The activation of NLRP3 inflammasome weakened NaHS improvement of NAFLD, indicating that exogenous H2S ameliorated NAFLD by inhibiting NLRP3 inflammasome-mediated lipid synthesis, inflammation, apoptosis and pyroptosis. Similarly, the activation of ER stress weakened NaHS improvement of NAFLD and NaHS inhibition of NLRP3 inflammasome, indicating that exogenous H2S suppressed NLRP3 inflammasome by downregulating ER stress, thus improving NAFLD. Additionally, the protein expressions of NLRP3 and cleaved caspase-1 were downregulated after inhibiting the reactive oxygen species (ROS)/extracellular signal-regulated kinases (ERK) and ROS/thioredoxin-interacting protein (TXNIP) pathways, indicating that ER stress activated NLRP3 inflammasome through the ROS/ERK and ROS/TXNIP pathways. In conclusion, our results indicated that exogenous H2S inhibited NLRP3 inflammasome-mediated hepatocytes inflammation, lipid synthesis, apoptosis and pyroptosis by downregulating ER stress, thereby improving NAFLD; Furthermore, ER stress activated NLRP3 inflammasome through the ROS/ERK and ROS/TXNIP pathways in NAFLD. ER stress/NLRP3 inflammasome is expected to become a new target of H2S for treating NAFLD.

Anti-obesity effects of Beta vulgaris and Eruca sativa-based extracts

Obesity is a major source of morbidity worldwide with more than 2 billion adults being overweight or obese. The incidence of obesity has tripled in the last 50 years, leading to an increased risk for a variety of noncommunicable diseases. Previous studies have demonstrated the positive effects of green leafy vegetables on weight gain and obesity and have attributed these beneficial properties, at least in part, to nitrates and isothiocyanates. Nitrates are converted to nitric oxide (NO) and isothiocyanates are known to release hydrogen sulfide (H2S). Herein, we investigated the effect of extracts and fractions produced from Beta vulgaris and Eruca sativa for their ability to limit lipid accumulation, regulate glucose homeostasis, and reduce body weight. Extracts from the different vegetables were screened for their ability to limit lipid accumulation in adipocytes and hepatocytes and for their ability to promote glucose uptake in skeletal muscle cultures; the most effective extracts were next tested in vivo. Wild type mice were placed on high-fat diet for 8 weeks to promote weight gain; animals receiving the selected B. vulgaris and E. sativa extracts exhibited attenuated body weight. Treatment with extracts also led to reduced white adipose tissue depot mass, attenuated adipocyte size, reduced expression of Dgat2 and PPARγ expression, and improved liver steatosis. In contrast, the extracts failed to improve glucose tolerance in obese animals and did not affect blood pressure. Taken together, our data indicate that extracts produced from B. vulgaris and E. sativa exhibit anti-obesity effects, suggesting that dietary supplements containing nitrates and sulfide-releasing compounds might be useful in limiting weight gain.

Pharmacology of Hydrogen Sulfide and Its Donors in Cardiometabolic Diseases

Cardiometabolic diseases (CMDs) are major contributors to global mortality, emphasizing the critical need for novel therapeutic interventions. Hydrogen sulfide (H2S) has garnered enormous attention as a significant gasotransmitter with various physiological, pathophysiological, and pharmacological impacts within mammalian cardiometabolic systems. In addition to its roles in attenuating oxidative stress and inflammatory response, burgeoning research emphasizes the significance of H2S in regulating proteins via persulfidation, a well known modification intricately associated with the pathogenesis of CMDs. This review seeks to investigate recent updates on the physiological actions of endogenous H2S and the pharmacological roles of various H2S donors in addressing diverse aspects of CMDs across cellular, animal, and clinical studies. Of note, advanced methodologies, including multiomics, intestinal microflora analysis, organoid, and single-cell sequencing techniques, are gaining traction due to their ability to offer comprehensive insights into biomedical research. These emerging approaches hold promise in characterizing the pharmacological roles of H2S in health and diseases. We will critically assess the current literature to clarify the roles of H2S in diseases while also delineating the opportunities and challenges they present in H2S-based pharmacotherapy for CMDs. SIGNIFICANCE STATEMENT: This comprehensive review covers recent developments in H2S biology and pharmacology in cardiometabolic diseases CMDs. Endogenous H2S and its donors show great promise for the management of CMDs by regulating numerous proteins and signaling pathways. The emergence of new technologies will considerably advance the pharmacological research and clinical translation of H2S.

The hydrogen sulfide donor 4-carboxyphenyl-isothiocyanate decreases blood pressure and promotes cardioprotective effect through reduction of oxidative stress and nuclear factor kappa B/matrix metalloproteinase (MMP)-2 axis in hypertension

AIMS

Our aim was to evaluate whether the hydrogen sulfide (H2S) donor, 4-carboxyphenyl-isothiocyanate (4-CPI), exerts cardioprotective effect in the two kidney- one clip (2K-1C) rats through oxidative stress and MMP-2 activity attenuation and compare it with the classical H2S donor, Sodium Hydrosulfide (NaHS).

MATERIALS AND METHODS

Renovascular hypertension (two kidneys-one clip; 2K-1C) was surgically induced in male Wistar rats. After two weeks, normotensive (2K) and hypertensive rats were intraperitoneally treated with vehicle (0.6 % dimethyl sulfoxide), NaHS (0.24 mg/Kg/day) or with 4-CPI (0.24 mg/Kg/day), for more 4 weeks. Systolic blood pressure (SBP) was evaluated weekly by tail-cuff plethysmography. Heart function was assessed by using the Millar catheter. Cardiac hypertrophy and fibrosis were evaluated by hematoxylin and eosin, and Picrosirius Red staining, respectively. The H2S was analyzed using WSP-1 fluorimetry and the cardiac oxidative stress was measured by lucigenin chemiluminescence and Amplex Red. MMP-2 activity was measured by in-gel gelatin or in situ zymography assays. Nox1, gp91phox, MMP-2 and the phospho-p65 subunit (Serine 279) nuclear factor kappa B (NF-κB) levels were evaluated by Western blotting.

KEY FINDINGS

4-CPI reduced blood pressure in hypertensive rats, decreased cardiac remodeling and promoted cardioprotection through the enhancement of cardiac H2S levels. An attenuation of oxidative stress, with inactivation of the p65-NF-κB/MMP-2 axis was similarly observed after NaHS or 4-CPI treatment in 2K-1C hypertension.

SIGNIFICANCE

H2S is a mediator that promotes cardioprotective effects and decreases blood pressure, and 4-CPI seems to be a good candidate to reverse the maladaptive remodeling and cardiac dysfunction in renovascular hypertension.

The role of hydrogen sulfide regulation of pyroptosis in different pathological processes

Pyroptosis is one kind of programmed cell death in which the cell membrane ruptures and subsequently releases cell contents and pro-inflammatory cytokines including IL-1β and IL-18. Pyroptosis is caused by many types of pathological stimuli, such as hyperglycemia (HG), oxidative stress, and inflammation, and is mediated by gasdermin (GSDM) protein family. Increasing evidence indicates that pyroptosis plays an important role in multiple diseases, such as cancer, kidney diseases, inflammatory diseases, and cardiovascular diseases. Therefore, the regulation of pyroptosis is crucial for the occurrence, development, and treatment of many diseases. Hydrogen sulfide (H2S) is a biologically active gasotransmitter following carbon monoxide (CO) and nitrogen oxide (NO) in mammalian tissues. So far, three enzymes, including 3-mercaptopyruvate sulphurtransferase (3-MST), cystathionine γ- Lyase (CSE), and Cystine β-synthesis enzyme (CBS), have been found to catalyze the production of endogenous H2S in mammals. H2S has been reported to have multiple biological functions including anti-inflammation, anti-oxidative stress, anti-apoptosis and so on. Hence, H2S is involved in various physiological and pathological processes. In recent years, many studies have demonstrated that H2S plays a critical role by regulating pyroptosis in various pathological processes, such as ischemia-reperfusion injury, alcoholic liver disease, and diabetes cardiomyopathy. However, the relevant mechanism has not been completely understood. Therefore, elucidating the mechanism by which H2S regulates pyroptosis in diseases will help understand the pathogenesis of multiple diseases and provide important new avenues for the treatment of many diseases. Here, we reviewed the progress of H2S regulation of pyroptosis in different pathological processes, and analyzed the molecular mechanism in detail to provide a theoretical reference for future related research.

Hydrogen sulfide responsive nanoplatforms: Novel gas responsive drug delivery carriers for biomedical applications

Hydrogen sulfide (H2S) is a toxic, essential gas used in various biological and physical processes and has been the subject of many targeted studies on its role as a new gas transmitter. These studies have mainly focused on the production and pharmacological side effects caused by H2S. Therefore, effective strategies to remove H2S has become a key research topic. Furthermore, the development of novel nanoplatforms has provided new tools for the targeted removal of H2S. This paper was performed to review the association between H2S and disease, related H2S inhibitory drugs, as well as H2S responsive nanoplatforms (HRNs). This review first analyzed the role of H2S in multiple tissues and conditions. Second, common drugs used to eliminate H2S, as well as their potential for combination with anticancer agents, were summarized. Not only the existing studies on HRNs, but also the inhibition H2S combined with different therapeutic methods were both sorted out in this review. Furthermore, this review provided in-depth analysis of the potential of HRNs about treatment or detection in detail. Finally, potential challenges of HRNs were proposed. This study demonstrates the excellent potential of HRNs for biomedical applications.

Diabetic Nephropathy and Gaseous Modulators

Diabetic nephropathy (DN) remains the leading cause of vascular morbidity and mortality in diabetes patients. Despite the progress in understanding the diabetic disease process and advanced management of nephropathy, a number of patients still progress to end-stage renal disease (ESRD). The underlying mechanism still needs to be clarified. Gaseous signaling molecules, so-called gasotransmitters, such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S), have been shown to play an essential role in the development, progression, and ramification of DN depending on their availability and physiological actions. Although the studies on gasotransmitter regulations of DN are still emerging, the evidence revealed an aberrant level of gasotransmitters in patients with diabetes. In studies, different gasotransmitter donors have been implicated in ameliorating diabetic renal dysfunction. In this perspective, we summarized an overview of the recent advances in the physiological relevance of the gaseous molecules and their multifaceted interaction with other potential factors, such as extracellular matrix (ECM), in the severity modulation of DN. Moreover, the perspective of the present review highlights the possible therapeutic interventions of gasotransmitters in ameliorating this dreaded disease.