Biological Effects of Morpholin-4-Ium 4 Methoxyphenyl (Morpholino) Phosphinodithioate and Other Phosphorothioate-Based Hydrogen Sulfide Donors

Advancements in increasing efficiency of hydrogen sulfide in therapeutics: Strategies for targeted delivery as prodrugs

Hydrogen sulfide (H2S) has emerged as a potent therapeutic agent with diverse physiological functions, including vasodilation, anti-inflammation, and cytoprotection. However, its clinical application is limited due to its volatility and potential toxicity at high concentrations. To address these challenges, researchers have developed various H2S prodrugs that release H2S in a controlled and targeted manner. The review underscores the importance of targeting and delivery strategies in maximizing the therapeutic potential of H2S, a gasotransmitter with diverse physiological functions and therapeutic effects. By summarizing recent advancements, the review provides valuable insights for researchers and clinicians interested in harnessing the therapeutic benefits of H2S while minimizing off-target effects and toxicity. The integration of novel targeting and delivery approaches not only enhances the efficacy of H2S-based therapeutics but also expands the scope of potential applications, offering promising avenues for the development of new treatments for a variety of diseases and disorders.

Hydrogen sulfide and sulfaceutic or sulfanutraceutic agents: Classification, differences and relevance in preclinical and clinical studies

Hydrogen sulfide (H2S) has been extensively studied as a signal molecule in the body for the past 30 years. Researchers have conducted studies using both natural and synthetic sources of H2S, known as H2S donors, which have different characteristics in terms of how they release H2S. These donors can be inorganic salts or have various organic structures. In recent years, certain types of sulfur compounds found naturally in foods have been characterized as H2S donors and explored for their potential health benefits. These compounds are referred to as "sulfanutraceuticals," a term that combines "nutrition" and "pharmaceutical". It is used to describe products derived from food sources that offer additional health advantages. By introducing the terms "sulfaceuticals" and "sulfanutraceuticals," we categorize sulfur-containing substances based on their origin and their use in both preclinical and clinical research, as well as in dietary supplements.

GYY4137, a H2S donor, ameliorates kidney injuries in diabetic mice by modifying renal ROS-associated enzymes

Diabetic nephropathy (DN) is a common microvascular complication of both type 1 and type 2 diabetes mellitus and often advances to end-stage renal disease. Oxidative stress plays an important role in the pathogenesis and progress of DN. Hydrogen sulfide (H₂S) is considered as a promising candidate for the management of DN. But the antioxidant effects of H₂S in DN have not been fully studied. In mouse model induced by high-fat diet and streptozotocin, GYY4137, a H₂S donor, ameliorated albuminuria at weeks 6 & 8 and decreased serum creatinine at week 8, but not hyperglycemia. Renal nitrotyrosine and urinary 8-isoprostane were reduced along with the suppressed levels of renal laminin and kidney-injury-molecule 1. Renal NADPH oxidase (NOX) 2 was lower but heme oxygenase (HO) 2, paraoxonase (PON) 1, PON2 were higher in DN+GYY than DN group. NOX1, NOX4, HO1, superoxide dismutases 1-3 were similar between groups. Except for a rise at HO2, all the affected enzymes were unchanged in mRNA levels. The affected reactive-oxygen-species (ROS) enzymes were mainly located in the renal sodium-hydrogen-exchanger positive proximal tubules with similar distribution but changed immunofluorence in GYY4137 treated DN mice. Kidney morphological alterations in DN mice under light and electrical-microscopes were also improved by GYY4137. Thus, exogenous H₂S administration may improve the renal oxidative damage in DN by reducing ROS production and enhancing ROS cleavage in kidney via the affected enzymes. This study may shed a light on therapeutic applications in diabetic nephropathy with H₂S donors in the future.

Insights into self-degradation of cysteine esters and amides under physiological conditions yield new cleavable chemistry

An unprecedented H₂S release from cysteine esters and amides (CysO/NHR) under physiological conditions was discovered and the plausible mechanism was proposed. Alkylation of the amino moiety of cysteine esters enables the H₂S release to be tuned and further provides support to the mechanistic insights. This discovery not only provides new insights into several fundamental science issues including non-enzymatic H₂S-produced pathways, but also inspires new tunable cleavable motifs for sustained release of arylthiols and even for prodrug design.

Recent advances and mechanistic interactions of hydrogen sulfide with plant growth regulators in relation to abiotic stress tolerance in plants

Adverse environmental constraints such as drought, heat, cold, salinity, and heavy metal toxicity are the primary concerns of the agricultural industry across the globe, as these stresses negatively affect yield and quality of crop production and therefore can be a major threat to world food security. Recently, it has been demonstrated that hydrogen sulfide (H₂S), which is well-known as a gasotransmitter in animals, also plays a potent role in various growth and developmental processes in plants. H₂S, as a potent signaling molecule, is involved in several plant processes such as in the regulation of stomatal pore movements, seed germination, photosynthesis and plant adaptation to environmental stress through gene regulation, post-translation modification of proteins and redox homeostasis. Moreover, a number of experimental studies have revealed that H₂S could improve the adaptation capabilities of plants against diverse environmental constraints by mitigating the toxic and damaging effects triggered by stressful environments. An attempt has been made to uncover recent development in the biosynthetic and metabolic pathways of H₂S and various physiological functions modulated in plants, H₂S donors, their functional mechanism, and application in plants. Specifically, our focus has been on how H₂S is involved in combating the destructive effects of abiotic stresses and its role in persulfidation. Furthermore, we have comprehensively elucidated the crosstalk of H₂S with plant growth regulators.

Hydrogen Sulfide and Its Donors: Keys to Unlock the Chains of Nonalcoholic Fatty Liver Disease

Hydrogen sulfide (H2S) has emerged as the third “gasotransmitters” and has a crucial function in the diversity of physiological functions in mammals. In particular, H2S is considered indispensable in preventing the development of liver inflammation in the case of excessive caloric ingestion. Note that the concentration of endogenous H2S was usually low, making it difficult to discern the precise biological functions. Therefore, exogenous delivery of H2S is conducive to probe the physiological and pathological roles of this gas in cellular and animal studies. In this review, the production and metabolic pathways of H2S in vivo, the types of donors currently used for H2S release, and study evidence of H2S improvement effects on nonalcoholic fatty liver disease are systematically introduced.

Peculiar features of bone marrow cell proliferation in Djungarian hamsters with genetic disorders under thiotepa effect

The paper aims to examine the proliferation of bone marrow cell pool in Djungarian hamsters and the subsequent restoration of their genetic stability after the action of thiotepa (TT). The study involved 36 animals, of which 16 were in the control group (injected with 0.25 ml of physiological solution), and 20 in the experimental group (0.25 ml of thiotepa at a dose of 1.5 mg per 1 kg of body weight). The maximum number of cells with CA amounting to 30.0% was observed 13 hours after TT injection (p≤0.05 between the control and experimental groups) and rapidly declined to 5.7% over subsequent periods by the 37th hour of the experiment (p≤0.05). The results suggest that the restoration of cell pool genetic stability is largely associated with the cell selection mechanisms, which confers an advantage over cell proliferation without chromosome anomalies.

The Anxiolytic and Antidepressant Effects of Diallyl Disulfide and GYY4137 in Animals with Chronic Neuropathic Pain

When neuropathic pain is maintained long term, it can also lead to the development of emotional disorders that are even more intense than pain perception and difficult to treat. Hydrogen sulfide (H₂S) donors relieve chronic pain, but their effects on the associated mood disorders are not completely elucidated. We evaluated if treatment with DADS (diallyl disulfide) or GYY4137 (morpholin-4-ium 4-methoxyphenyl(morpholino) phosphinodithioate dichloromethane complex), two slow-releasing H₂S donors, inhibits the anxiety- and depressive-like behaviors that concur with chronic neuropathic pain generated by sciatic nerve injury in mice. The modulatory role of these drugs in the inflammatory, apoptotic, and oxidative processes implicated in the development of the affective disorders was assessed. Our results revealed the anxiolytic, antidepressant, and antinociceptive properties of DADS and GYY4137 during neuropathic pain by inhibiting microglial activation and the up-regulation of phosphoinositide 3-kinase/phosphorylated protein kinase B and BAX in the amygdala (AMG) and/or periaqueductal gray matter (PAG). Both treatments also normalized and/or activated the endogenous antioxidant system, but only DADS blocked ERK 1/2 phosphorylation. Both H₂S donors decreased allodynia and hyperalgesia in a dose-dependent manner by activating the Kv7 potassium channels and heme oxygenase 1 signaling pathways. This study provides evidence of the anxiolytic and antidepressant properties of DADS and GYY4137 during neuropathic pain and reveals their analgesic actions, suggesting that these therapeutic properties may result from the inhibition of the inflammatory, apoptotic, and oxidative responses in the AMG and/or PAG. These findings support the use of these treatments for the management of affective disorders accompanying chronic neuropathic pain.

Cysteine metabolic circuitries: druggable targets in cancer

To enable survival in adverse conditions, cancer cells undergo global metabolic adaptations. The amino acid cysteine actively contributes to cancer metabolic remodelling on three different levels: first, in its free form, in redox control, as a component of the antioxidant glutathione or its involvement in protein s-cysteinylation, a reversible post-translational modification; second, as a substrate for the production of hydrogen sulphide (H2S), which feeds the mitochondrial electron transfer chain and mediates per-sulphidation of ATPase and glycolytic enzymes, thereby stimulating cellular bioenergetics; and, finally, as a carbon source for epigenetic regulation, biomass production and energy production. This review will provide a systematic portrayal of the role of cysteine in cancer biology as a source of carbon and sulphur atoms, the pivotal role of cysteine in different metabolic pathways and the importance of H2S as an energetic substrate and signalling molecule. The different pools of cysteine in the cell and within the body, and their putative use as prognostic cancer markers will be also addressed. Finally, we will discuss the pharmacological means and potential of targeting cysteine metabolism for the treatment of cancer.

On H2S Prodrugs

This Forum was conceived as a means to usher in the age of H₂S-based therapeutics and H₂S-aided regenerative medicine. H₂S prodrugs-now in advanced stages of pharmaceutical development-will soon be available for treatment of a remarkably wide range of serious health conditions with minimal side effects/adverse reactions. Also foreseeable is the advent of a time in which the "one drug-one target" paradigm will be phased out, whereas multitargeted H₂S prodrugs find expanding roles in the treatment of highly complex disease states-such paradigm change will prevent polypharmacy and bring about truly disease-modifying outcomes. In the seven articles comprising Parts A and B of this Forum (2-4, 6-9), international experts survey remarkably diverse landscapes of small and large H₂S donor molecules, H₂S release profiles and mechanisms, pharmacophores/metabolic routes, and potential therapeutic or prophylactic indications. Donors of related sulfur species, such as persufides, SO₂, carbon oxysulfide (COS), and carbon disulfide, are examined as well. This Editorial highlights a few of the insights shared by the 32 Forum contributors and includes a proposed classification of H₂S/COS prodrugs that is intended to aid in the systematization of this burgeoning field.

Implications of hydrogen sulfide in liver pathophysiology: Mechanistic insights and therapeutic potential

Background

Over the last several decades, hydrogen sulfide (H₂S) has been found to exert multiple physiological functions in mammal systems. The endogenous production of H₂S is primarily mediated by cystathione β-synthase (CBS), cystathione γ-lyase (CSE), and 3-mercaptopyruvate sulfurtransferase (3-MST). These enzymes are widely expressed in the liver tissues and regulate hepatic functions by acting on various molecular targets.

Aim of Review

In the present review, we will highlight the recent advancements in the cellular events triggered by H₂S under liver diseases. The therapeutic effects of H₂S donors on hepatic diseases will also be discussed.

Key Scientific Concepts of Review

As a critical regulator of liver functions, H₂S is critically involved in the etiology of various liver disorders, such as nonalcoholic steatohepatitis (NASH), hepatic fibrosis, hepatic ischemia/reperfusion (IR) injury, and liver cancer. Targeting H₂S-producing enzymes may be a promising strategy for managing hepatic disorders.

Hydrogen Sulfide, Adipose Tissue and Diabetes Mellitus

Hydrogen sulfide (H₂S) is now increasingly considered to be the third gasotransmitter alongside other gaseous signaling molecules, nitric oxide (NO) and carbon monoxide (CO). H₂S is produced by a variety of endogenous enzymatic and non-enzymatic pathways and acts as a modulator of the physiological and pathological events of the body. Adipocytes express the cystathionine γ lyase (CSE)/H₂S system, which modulates a variety of biological activities in adipose tissue (AT), including inflammation, apoptosis, insulin resistance, adipokine secretion and adipocyte differentiation. Abnormalities in the physiological functions of AT play an important role in the process of diabetes mellitus. Therefore, this review provides an overview of the general aspects of H₂S biochemistry, the effect of H₂S on AT function and diabetes mellitus and its molecular signalling mechanisms as well as the potential application of H₂S in pharmacotherapy.