Hydrogen Sulfide: A Gaseous Mediator and Its Key Role in Programmed Cell Death, Oxidative Stress, Inflammation and Pulmonary Disease

ASB1 engages with ELOB to facilitate SQOR ubiquitination and H2S homeostasis during spermiogenesis

Male infertility, frequently driven by oxidative stress, impacts half of infertile couples globally. Despite its significance, the precise mechanisms governing this process remain elusive. In this study, we demonstrate that ASB1, the substrate recognition subunit of a ubiquitin ligase, is highly expressed in the mouse testis. Mice lacking the Asb1 gene exhibit severe fertility impairment, characterized by oligoasthenoteratozoospermia. Subsequent investigations unveiled that Asb1 knockout (Asb1-KO) mice encountered excessive oxidative stress and decreased hydrogen sulfide (H2S) levels in their testes, and severe sperm DNA damage. Notably, the compromised fertility and sperm quality in Asb1-KO mice was significantly ameliorated by administering NaHS, a H2S donor. Mechanistically, ASB1 interacts with ELOB to induce the instability of sulfide-quinone oxidoreductase (SQOR) by enhancing its K48-linked ubiquitination on residues K207 and K344, consequently triggering proteasomal degradation. This process is crucial for preserving H2S homeostasis and redox balance. Overall, our findings offer valuable insights into the role of ASB1 during spermiogenesis and propose H2S supplementation as a promising therapeutic approach for oxidative stress-related male infertility.

Polyphenol-mediated redox-active hydrogel with H2S gaseous-bioelectric coupling for periodontal bone healing in diabetes

Excessive oxidative response, unbalanced immunomodulation, and impaired mesenchymal stem cell function in periodontitis in diabetes makes it a great challenge to achieve integrated periodontal tissue regeneration. Here, a polyphenol-mediated redox-active algin/gelatin hydrogel encapsulating a conductive poly(3,4-ethylenedioxythiopene)-assembled polydopamine-mediated silk microfiber network and a hydrogen sulfide sustained-release system utilizing bovine serum albumin nanoparticles is developed. This hydrogel is found to reverse the hyperglycemic inflammatory microenvironment and enhance functional tissue regeneration in diabetic periodontitis. Polydopamine confers the hydrogel with anti-oxidative and anti-inflammatory activity. The slow, sustained release of hydrogen sulfide from the bovine serum albumin nanoparticles recruits mesenchymal stem cells and promotes subsequent angiogenesis and osteogenesis. Moreover, poly(3,4-ethylenedioxythiopene)-assembled polydopamine-mediated silk microfiber confers the hydrogel with good conductivity, which enables it to transmit endogenous bioelectricity, promote cell arrangement, and increase the inflow of calcium ion. In addition, the synergistic effects of hydrogen sulfide gaseous-bioelectric coupling promotes bone formation by amplifying autophagy in periodontal ligament stem cells and modulating macrophage polarization via lipid metabolism regulation. This study provides innovative insights into the synergistic effects of conductivity, reactive oxygen species scavenging, and hydrogen sulfide on the periodontium in a hyperglycemic inflammatory microenvironment, offering a strategy for the design of gaseous-bioelectric biomaterials to promote functional tissue regeneration in immune-related diseases.

Nanotechnology-Mediated Immunomodulation Strategy for Inflammation Resolution

Inflammation serves as a common characteristic across a wide range of diseases and plays a vital role in maintaining homeostasis. Inflammation can lead to tissue damage and the onset of inflammatory diseases. Although significant progress is made in anti-inflammation in recent years, the current clinical approaches mainly rely on the systemic administration of corticosteroids and antibiotics, which only provide short-term relief. Recently, immunomodulatory approaches have emerged as promising strategies for facilitating the resolution of inflammation. Especially, the advanced nanosystems with unique biocompatibility and multifunctionality have provided an ideal platform for immunomodulation. In this review, the pathophysiology of inflammation and current therapeutic strategies are summarized. It is mainly focused on the nanomedicines that modulate the inflammatory signaling pathways, inflammatory cells, oxidative stress, and inflammation targeting. Finally, the challenges and opportunities of nanomaterials in addressing inflammation are also discussed. The nanotechnology-mediated immunomodulation will open a new treatment strategy for inflammation therapy.

Hydrogen sulfide regulates macrophage polarization and necroptosis to accelerate diabetic skin wound healing

Hydrogen sulfide (H2S), recognized as the third gasotransmitter, plays a pivotal role in the pathophysiological processes of various diseases. Cystathionine γ-lyase (CSE) is the main enzyme for H2S production in the skin. However, effects and mechanisms of H2S in diabetic skin wound healing remain unclear. Our findings revealed a decrease in plasma H2S content in diabetic patients with skin wounds. CSE knockout (KO) diabetic mice resulted in delayed wound healing, reduced blood perfusion, and CD31 expression around the wounds. It also led to increased infiltration of inflammatory cells and M1-type macrophages, decreased collagen levels, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression. Additionally, there were enhanced expressions of necroptosis related proteins, including receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain like protein (MLKL). In comparison, sodium hydrosulfide (NaHS), H2S donor, accelerated skin wound healing in leptin receptor deficiency (db/db) mice. This acceleration was accompanied by increased blood perfusion and CD31 expression, reduced infiltration of inflammatory cells and M1-type macrophages, elevated collagen levels, α-SMA, and PCNA expressions, and decreased necroptosis-related protein expressions together with nuclear factor-κB (NF-κB) p65 phosphorylation. In conclusion, H2S regulates macrophage polarization and necroptosis, contributing to the acceleration of diabetic skin wound healing. These findings offer a novel strategy for the treatment of diabetic skin wounds.

Suppressing the Substance P-NK1R Signalling Protects Mice against Sepsis-Associated Acute Inflammatory Injury and Ferroptosis in the Liver and Lungs

Substance P (SP), encoded by the TAC1/Tac1 gene, acts as a significant mediator in dysregulated systemic inflammatory response and associated organ injury in sepsis by activating the neurokinin-1 receptor (NK1R). This study investigated the impact of SP-NK1R signaling on ferroptosis in the liver and lungs of mice with sepsis. Sepsis was induced by caecal ligation puncture (CLP) surgery in mice. The SP-NK1R signaling was suppressed by Tac1 gene deletion, NK1R blockade, and a combination of these two approaches. The physiological conditions of mice were recorded. The profile of the SP-NK1R cascade, inflammatory response, ferroptosis, and tissue histology were investigated in the liver and lungs. Several manifestations of sepsis occurred in Tac1+/+ mice during the development of sepsis. Notably, hypothermia became significant four hours after the induction of sepsis. In the liver and lungs of mice subjected to CLP surgery, the concentrations of SP and NK1R were upregulated. Additionally, the concentrations of pro-inflammatory mediators, including cytokines (IL-1β, IL-6, and TNF-α) and chemokines (MCP-1 and MIP-2), were increased. Moreover, ferroptosis was elevated, as evidenced by increased concentrations of iron and MDA and reduced concentrations of GSH, Nrf2, and Gpx4. Suppressing the SP-NK1R cascade significantly mitigated CLP-surgery-induced alterations in mice. Importantly, these three approaches used to suppress SP-NK1R signaling showed similar effects on protecting mice against sepsis. In conclusion, increased SP-mediated acute inflammatory response and injury in the liver and lungs in mice with CLP-surgery-induced sepsis was associated with elevated ferroptosis. The detrimental effect of SP on sepsis was predominantly mediated by NK1R. Therefore, the suppression of increased SP-NK1R signaling and ferroptosis may be a promising adjuvant therapeutic candidate for sepsis and associated acute liver and lung injury.

Endogenous hydrogen sulphide deficiency and exogenous hydrogen sulphide supplement regulate skin fibroblasts proliferation via necroptosis

An excessive proliferation of skin fibroblasts usually results in different skin fibrotic diseases. Hydrogen sulphide (H2 S) is regarded as an important endogenous gasotransmitter with various functions. The study aimed to investigate the roles and mechanisms of H2 S on primary mice skin fibroblasts proliferation. Cell proliferation and collagen synthesis were assessed with the expression of α-smooth muscle actin (α-SMA), proliferating cell nuclear antigen (PCNA), Collagen I and Collagen III. The degree of oxidative stress was evaluated by dihydroethidium (DHE) and MitoSOX staining. Mitochondrial membrane potential (ΔΨm) was detected by JC-1 staining. Necroptosis was evaluated with TDT-mediated dUTP nick end labelling (TUNEL) and expression of receptor-interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like protein (MLKL). The present study found that α-SMA, PCNA, Collagen I and Collagen III expression were increased, oxidative stress was promoted, ΔΨm was impaired and positive rate of TUNEL staining, RIPK1 and RIPK3 expression as well as MLKL phosphorylation were all enhanced in skin fibroblasts from cystathionine γ-lyase (CSE) knockout (KO) mice or transforming growth factor-β1 (TGF-β1, 10 ng/mL)-stimulated mice skin fibroblasts, which was restored by exogenous sodium hydrosulphide (NaHS, 50 μmol/L). In conclusion, endogenous H2 S production impairment in CSE-deficient mice accelerated skin fibroblasts proliferation via promoted necroptosis, which was attenuated by exogenous H2 S. Exogenous H2 S supplement alleviated proliferation of skin fibroblasts with TGF-β1 stimulation via necroptosis inhibition. This study provides evidence for H2 S as a candidate agent to prevent and treat skin fibrotic diseases.

The Role of Hydrogen Sulfide in the Localization and Expression of p53 and Cell Death in the Nervous Tissue in Traumatic Brain Injury and Axotomy

Traumatic brain injury (TBI) is one of the leading causes of disability and death worldwide. It is characterized by various molecular-cellular events, with the main ones being apoptosis and damage to axons. To date, there are no clinically effective neuroprotective drugs. In this study, we examined the role of hydrogen sulfide (H2S) in the localization and expression of the key pro-apoptotic protein p53, as well as cell death in the nervous tissue in TBI and axotomy. We used a fast donor (sodium sulphide, Na2S) H2S and a classic inhibitor (aminooxyacetic acid, AOAA) of cystathionine β-synthase (CBS), which is a key enzyme in H2S synthesis. These studies were carried out on three models of neurotrauma in vertebrates and invertebrates. As a result, it was found that Na2S exhibits a pronounced neuroprotective effect that reduces the number of TUNEL-positive neurons and glial cells in TBI and apoptotic glia in axotomy. This effect could be realized through the Na2S-dependent decrease in the level of p53 in the cells of the nervous tissue of vertebrates and invertebrates, which we observed in our study. We also observed the opposite effect when using AOAA, which indicates the important role of CBS in the regulation of p53 expression and death of neurons and glial cells in TBI and axotomy.

The Effects of Novel Triazolopyrimidine Derivatives on H2S Production in Lung and Vascular Tonus in Aorta

INTRODUCTION

Hydrogen sulfide (H2S), known as a third gasotransmitter, is a signaling molecule that plays a regulatory role in physiological and pathophysiological processes. Decreased H2S levels were reported in inflammatory respiratory diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary hypertension. H2S donors or drugs that increase H2S have emerged as novel treatments for inflammatory respiratory diseases. We previously showed that resveratrol (RVT) causes vascular relaxation and antioxidant effects by inducing H2S production. In the current study, we synthesized a new molecule Cpd2, as an RVT analog. We examined the effect of Cpd2 and its precursor chalcone compound (Cpd1) on H2S formation under both healthy and oxidative stress conditions in the lung, as well as vascular relaxation in the aorta.

METHODS

Cpd2 synthesized from Cpd1 with microwaved in basic conditions. H2S formation was measured by H2S biosensor in the mice lungs under both healthy and pyrogallol-induced oxidative stress conditions in the presence/absence of H2S synthesis inhibitor aminooxyacetic acid (AOAA). The effect of compounds on vascular tonus is investigated in mice aorta by DMT myograph.

RESULTS

RVT and Cpd2 significantly increased l-cysteine (l-cys) induced-H2S formation in the lung homogenates of healthy mice, but Cpd1 did not. Superoxide anion generator pyrogallol caused a decrease in H2S levels in mice lungs and Cpd2 restored it. Inhibition of Cpd2-induced H2S formation by AOAA confirmed that Cpd2 increases endogenous H2S formation in both healthy and oxidative stress conditions. Furthermore, we found that both Cpd1 and Cpd2 (10-8-10-4 M) caused vascular relaxation in mice aorta.

DISCUSSION AND CONCLUSION

We found that Cpd2, a newly synthesized RVT analog, is an H2S-inducing molecule and vasorelaxant similar to RVT. Since H2S has antioxidant and anti-inflammatory effects, Cpd2 has a potential for the treatment of respiratory diseases where oxidative stress and decreased H2S levels are present.

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

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

Effect of hydrogen sulfide on ischemia-reperfusion injury of kidney: A systematic review and meta-analysis of in vivo animal studies

Hydrogen sulfide (H₂S) has been shown to be effective against kidney ischemia-reperfusion injury (IRI) in animal studies. We aimed to evaluate the current evidence from in vivo animal studies for the protective effects of H₂S against kidney IRI by systematically reviewing the literature and performing a meta-analysis. Based on the preregistered protocol (PROSPERO: CRD42021295469); PubMed, Medline, Embase, Web of Science, and Scopus were searched to identify in vivo animal studies evaluating the effect of H₂S against kidney IRI. Standardized mean difference (SMD) with 95% confidence interval (CI) was calculated and pooled using random-effects meta-analysis. Twenty-two articles complied with eligibility criteria, from which the creatinine levels of 152 control animals and 182 animals treated with H₂S from 27 individual experiments were pooled. H₂S treatment significantly decreased serum creatinine (SMD = -1.82 [95% CI -1.12, -2.51], p < 0.0001), blood urea nitrogen (-2.50 [-1.46, -3.54], p < 0.0001), tissue malondialdehyde (-2.59 [-3.30, -1.88], p < 0.0001), tunel positive cells (-3.16 [-4.38, -1.94], p < 0.0001), and tubular damage score (-2.01 [-3.03, -0.99], p < 0.0001). There was a high heterogeneity across studies (I² = 83.5% for serum creatinine level). In meta-regression analysis, the type of H₂S donor and its application time accounted for 11.3% (p = 0.025) and 16.6% (p = 0.039) of heterogeneity, respectively. Accordingly, H₂S protects the kidney against IRI only if it is given as GYY4137 before or during ischemia. Although H₂S is a potential candidate against kidney IRI, further well-designed preclinical studies focusing on GYY4137 are warranted before clinical implication.