Exogenous hydrogen sulfide mitigates LPS + ATP-induced inflammation by inhibiting NLRP3 inflammasome activation and promoting autophagy in L02 cells

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.

AGK2 pre-treatment protects against thioacetamide-induced acute liver failure via regulating the MFN2-PERK axis and ferroptosis signaling pathway

BACKGROUND

Acute liver failure (ALF) is an unpredictable and life-threatening critical illness. The pathological characteristic of ALF is massive necrosis of hepatocytes and lots of inflammatory cells infiltration which may lead to multiple organ failure.

METHODS

Animals were divided into 3 groups, normal, thioacetamide (TAA, ALF model) and TAA + AGK2. Cultured L02 cells were divided into 5 groups, normal, TAA, TAA + mitofusin 2 (MFN2)-siRNA, TAA + AGK2, and TAA + AGK2 + MFN2-siRNA groups. The liver histology was evaluated with hematoxylin and eosin staining, inositol-requiring enzyme 1 (IRE1), activating transcription factor 6β (ATF6β), protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) and phosphorylated-PERK (p-PERK). C/EBP homologous protein (CHOP), reactive oxygen species (ROS), MFN2 and glutathione peroxidase 4 (GPX4) were measured with Western blotting, and cell viability and liver chemistry were also measured. Mitochondria-associated endoplasmic reticulum membranes (MAMs) were measured by immunofluorescence.

RESULTS

The liver tissue in the ALF group had massive inflammatory cell infiltration and hepatocytes necrosis, which were reduced by AGK2 pre-treatment. In comparison to the normal group, apoptosis rate and levels of IRE1, ATF6β, p-PERK, CHOP, ROS and Fe2+ in the TAA-induced ALF model group were significantly increased, which were decreased by AGK2 pre-treatment. The levels of MFN2 and GPX4 were decreased in TAA-induced mice compared with the normal group, which were enhanced by AGK2 pre-treatment. Compared with the TAA-induced L02 cell, apoptosis rate and levels of IRE1, ATF6β, p-PERK, CHOP, ROS and Fe2+ were further increased and levels of MFN2 and GPX4 were decreased in the MFN2-siRNA group. AGK2 pre-treatment decreased the apoptosis rate and levels of IRE1, ATF6β, p-PERK, CHOP, ROS and Fe2+ and enhanced the protein expression of MFN2 and GPX4 in MFN2-siRNA treated L02 cell. Immunofluorescence observation showed that level of MAMs was promoted in the AGK2 pre-treatment group when compared with the TAA-induced group in both mice and L02 cells.

CONCLUSIONS

The data suggested that AGK2 pre-treatment had hepatoprotective role in TAA-induced ALF via upregulating the expression of MFN2 and then inhibiting PERK and ferroptosis pathway in ALF.

Application and value of hydrogen sulfide modulated autophagy in sepsis

Sepsis is is anabnormalhost immune responsecausedbyinfection. Antibiotics, anti-viral drugs, and vasoactive drugs have always been used in the traditional treatment of sepsis, but there are no specific and effective drugs in clinical practice. Autophagy is a highly conservative process in biological evolution, and plays an important role in maintaining intracellular homeostasis and cellular self-renewal. Autophagy can remove and degrade misfolding proteins and damaged organelles in cells, providing materials for cell repair and self-renewal. Hydrogen sulfide (H2S) is a colorless gas that smells likerotteneggs. It is the third endogenous gas signal molecule discovered after nitric oxide and carbon monoxide and has become a research hotspot in recent years. H2S has a variety of biological functions and plays an important role in various physiological and pathological processes. Thereisgrowingevidencethat H2S can regulate autophagy. The intervention of autophagy is a promising therapeutic strategy to improve sepsis organ damage. This article reviews the organ protection of autophagy in sepsis and the role of H2S in regulating autophagy in sepsis, revealing that H2S intervention with autophagy may be a a worthy target in sepsis treatment.

A Water-Soluble Hydrogen Sulfide Donor Suppresses the Growth of Hepatocellular Carcinoma via Inhibiting the AKT/GSK-3β/β-Catenin and TGF-β/Smad2/3 Signaling Pathways

Hepatocellular carcinoma (HCC) is a disease with high morbidity, high mortality, and low cure rate. Hyaluronic acid (HA) is widely adopted in tissue engineering and drug delivery. 5-(4-Hydroxyphenyl)-3H-1, 2-dithiol-3-thione (ADT-OH) is one of commonly used H₂S donors. In our previous study, HA-ADT was designed and synthesized via coupling of HA and ADT-OH. In this study, compared with sodium hydrosulfide (NaHS, a fast H₂S-releasing donor) and morpholin-4-ium (4-methoxyphenyl)-morpholin-4-ylsulfanylidenesulfido-λ5-phosphane (GYY4137, a slow H₂S-releasing donor), HA-ADT showed stronger inhibitory effect on the proliferation, migration, invasion, and cell cycle of human HCC cells. HA-ADT promoted apoptosis by suppressing the expressions of phospho (p)-protein kinase B (PKB/AKT), p-glycogen synthase kinase-3β (GSK-3β), p-β-catenin, and also inhibited autophagy via the downregulation of the protein levels of p-Smad2, p-Smad3, and transforming growth factor-β (TGF-β) in human HCC cells. Moreover, HA-ADT inhibited HCC xenograft tumor growth more effectively than both NaHS and GYY4137. Therefore, HA-ADT can suppress the growth of HCC cells by blocking the AKT/GSK-3β/β-catenin and TGF-β/Smad2/3 signaling pathways. HA-ADT and its derivatives may be developed as promising antitumor drugs.

The Role of Hydrogen Sulfide Targeting Autophagy in the Pathological Processes of the Nervous System

Autophagy is an important cellular process, involving the transportation of cytoplasmic contents in the double membrane vesicles to lysosomes for degradation. Autophagy disorder contributes to many diseases, such as immune dysfunction, cancers and nervous system diseases. Hydrogen sulfide (H₂S) is a volatile and toxic gas with a rotten egg odor. For a long time, it was considered as an environmental pollution gas. In recent years, H₂S is regarded as the third most important gas signal molecule after NO and CO. H₂S has a variety of biological functions and can play an important role in a variety of physiological and pathological processes. Increasingly more evidences show that H₂S can regulate autophagy to play a protective role in the nervous system, but the mechanism is not fully understood. In this review, we summarize the recent literatures on the role of H₂S in the pathological process of the nervous system by regulating autophagy, and analyze the mechanism in detail, hoping to provide the reference for future related research.

High-fidelity imaging of lysosomal enzyme through in situ ordered assembly of small molecular fluorescent probes

As an organelle in cells, lysosomes play an important role in the degradation of biological macromolecules and pathogens. To elucidate the function of lysosomes in normal or disease states, recently, various fluorescent probes have been reported for imaging lysosomal analytes. However, because of the particularity of the lysosomal environment, most of the reported lysosomal fluorescent probes suffered from a series of practical issues such as easy diffusion, low detection signal-to-background ratio and false signal. To address these issues, based on an optimized in situ ordered assembly solid-state fluorophore HDPQ, we herein put forward a new strategy for the design of lysosomal enzymes probes. As a proof concept, we synthesized a fluorescent probe HDPQ-GLU for lysosomal enzyme β-glucuronidase (GLU). Experiment results displayed that compared with general lysosomal probe, the novel lysosomal probe not only exhibited excellent anti-pH interference ability and high signal-to-noise ratio in aqueous solution, but also has excellent long-term in situ imaging ability in the living system. Using this probe, we have realized high-fidelity and long-term in situ tracking GLU in lysosomes of living cells and evaluated the dynamic changes of GLU during the growth period of zebrafish. We anticipate that the new strategy based on the novel in situ ordered assembly solid-state fluorophore HDPQ may be a potential platform for developing fluorescent probes for high-fidelity imaging of lysosomal enzymes.

The Emerging Role of EVA1A in Different Types of Cancers

Eva-1 homolog A (EVA1A), also known as transmembrane protein 166 (TMEM166) and regulator of programmed cell death, is an endoplasmic reticulum associated protein, which can play an important role in many diseases, including a variety of cancers, by regulating autophagy/apoptosis. However, the related mechanism, especially the role of EVA1A in cancers, has not been fully understood. In this review, we summarize the recent studies on the role of EVA1A in different types of cancers, including breast cancer, papillary thyroid cancer, non-small cell lung cancer, hepatocellular carcinoma, glioblastoma and pancreatic cancer, and analyze the relevant mechanisms to provide a theoretical basis for future related research.

The Protective Role of 4-Acetylarylquinolinol B in Different Pathological Processes

Antrodia cinnamomea is a traditional plant and a unique fungus native to Taiwan that has been reported to have many biological functions, including anti-inflammatory and anticancer activities. The compound 4-acetylarylquinolinol B (4-AAQB) is one of the main bioactive compounds in the stamens of Antrodia cinnamomea, and has many biological functions, such as anti-inflammatory, antiproliferative, blood sugar reduction, antimetastasis, and vascular tone relaxation. In recent years, the increasing evidences have shown that 4-AAQB is involved in many diseases; however, the relevant mechanisms have not been fully clarified. This review aimed to clarify the improvement by 4-AAQB in different pathological processes, as well as the compound’s molecular mechanisms, in order to provide a theoretical reference for future related research

The Role of Hydrogen Sulfide Regulation of Autophagy in Liver Disorders

Autophagy is a complex process of degradation of senescent or dysfunctional organelles in cells. Dysfunctional autophagy is associated with many diseases such as cancers, immune dysfunction, and aging. Hydrogen sulfide (H₂S) is considered to be the third gas signal molecule after nitrous oxide and carbon monoxide. In recent years, H₂S has been found to have a variety of important biological functions, and plays an important role in a variety of physiological and pathological processes. In this review, we review the recent role and mechanism of H₂S in regulating autophagy in liver disorders, in order to provide a basis for further research in the future.

Picroside II alleviates DSS-induced ulcerative colitis by suppressing the production of NLRP3 inflammasomes through NF-κB signaling pathway

CONTEXT

Ulcerative colitis (UC) is a common acute or chronic intestinal disease with the imbalance of inflammation. Picroside II (P-II) exerts the protective role in various inflammation-related diseases. However, the effect of P-II on UC is still unclear.

OBJECTIVE

To explore the effect of P-II on UC and its potential mechanism.

MATERIALS AND METHODS

Human monocytic leukemia cell line THP-1 were treated with phorbol ester (PMA) to differentiate into macrophage. The differentiated THP-1 cells were hatched with LPS combined with ATP or Nigericin to activate the NLRP3 inflammasome in vitro. The UC model was constructed by injection of DSS into mice.

RESULTS

The maximum non-toxic concentration of P-II on THP-1 cells was 60 μM. LPS combined with ATP or Nigericin stimulated the production of IL-1β, which was antagonized by P-II treatment. Meanwhile, P-II administration interfered the aggregation of ASC and the assembly of NLRP3 inflammasomes. Also, P-II treatment reduced the LPS and ATP-induced elevation of the relative protein expression of NLRP3, pro-caspase-1, IL-1β and p-p65/p65, and the concentration of TNF-α and IL-6. Besides, the NF-κB specific inhibitor BAY-117082 notably repressed the LPS together with ATP-enhanced the relative protein expression of NLRP3, caspase-1 and IL-1β. Moreover, in vivo results showed that P-II relieved the DDS-induced UC, as evidenced by the improvement of mice weight, DAI and pathological scores. In addition, P-II treatment notably decreased DDS-promoted expression of NLRP3 inflammasomes and inflammatory factors in vivo.

CONCLUSION

P-II alleviated DSS-induced UC by repressing the production of NLRP3 inflammasomes via NF-κB signaling pathway.

An Activatable Afterglow/MRI Bimodal Nanoprobe with Fast Response to H2 S for In Vivo Imaging of Acute Hepatitis

Accurate detection of hepatic hydrogen sulfide (H₂ S) to monitor H₂ S-related enzymes' activity is critical for acute hepatitis diagnosis, but remains a challenge due to the dynamic and transient nature of H₂ S. Here, we report a H₂ S-activatable near-infrared afterglow/MRI bimodal probe F1-GdNP, which shows an "always-on" MRI signal and "off-on" afterglow signal toward H₂ S. F1-GdNP shows fast response, high sensitivity and specificity toward H₂ S, permitting afterglow imaging of H₂ S and evaluation of cystathionine γ-lyase (CSE)'s activity in living mice. We further employ the high spatial-resolution MRI signal of F1-GdNP to track its delivery and accumulation in liver. Importantly, F1-GdNP offers a high signal-to-background ratio (SBR=86.2±12.0) to sensitively report on the increased hepatic H₂ S level in the acute hepatitis mice via afterglow imaging, which correlated well with the upregulated CSE activity in the liver, showcasing the good potential of F1-GdNP for monitoring of acute hepatitis process in vivo.

Hydrogen Sulfide and the Immune System

Hydrogen sulfide (H₂S) is the "third gasotransmitter" recognized alongside nitric oxide (NO) and carbon monoxide (CO). H₂S exhibits an array of biological effects in mammalian cells as revealed by studies showing important roles in the cardiovascular system, in cell signalling processes, post-translational modifications and in the immune system. Regarding the latter, using pharmacological and genetic approaches scientists have shown this molecule to have both pro- and anti-inflammatory effects in mammalian systems. The anti-inflammatory effects of H₂S appeared to be due to its inhibitory action on the nuclear factor kappa beta signalling pathway; NF-kB representing a transcription factor involved in the regulation pro-inflammatory mediators like nitric oxide, prostaglandins, and cytokines. In contrast, results from several animal model describe a more complicated picture and report on pro-inflammatory effects linked to exposure to this molecule; linked to dosage used and point of administration of this molecule. Overall, roles for H₂S in several inflammatory diseases spanning arthritis, atherosclerosis, sepsis, and asthma have been described by researchers. In light this work fascinating research, this chapter will cover H₂S biology and its many roles in the immune system.

Hydrogen sulfide and vascular regulation - An update

BACKGROUND

Hydrogen sulfide (H₂S) is considered to be the third gasotransmitter after carbon monoxide (CO) and nitric oxide (NO). It plays an important role in the regulation of vascular homeostasis. Vascular remodeling have has proved to be related to the impaired H₂S generation.

AIM OF REVIEW

This study aimed to summarize and discuss current data about the function of H₂S in vascular physiology and pathophysiology as well as the underlying mechanisms.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Endogenous hydrogen sulfide (H₂S) as a third gasotransmitter is primarily generated by the enzymatic pathways and regulated by several metabolic pathways. H₂S as a physiologic vascular regulator, inhibits proliferation, regulates its apoptosis and autophagy of vascular cells and controls the vascular tone. Accumulating evidence shows that the downregulation of H₂S pathway is involved in the pathogenesis of a variety of vascular diseases, such as hypertension, atherosclerosis and pulmonary hypertension. Alternatively, H₂S supplementation may greatly help to prevent the progression of the vascular diseases by regulating vascular tone, inhibiting vascular inflammation, protecting against oxidative stress and proliferation, and modulating vascular cell apoptosis, which has been verified in animal and cell experiments and even in the clinical investigation. Besides, H₂S system and angiotensin-converting enzyme (ACE) inhibitors play a vital role in alleviating ischemic heart disease and left ventricular dysfunction. Notably, sulfhydryl-containing ACEI inhibitor zofenopril is superior to other ACE inhibitors due to its capability of H₂S releasing, in addition to ACE inhibition. The design and application of novel H₂S donors have significant clinical implications in the treatment of vascular-related diseases. However, further research regarding the role of H₂S in vascular physiology and pathophysiology is required.

Role of hydrogen sulfide donors in cancer development and progression

In recent years, a vast number of potential cancer therapeutic targets have emerged. However, developing efficient and effective drugs for the targets is of major concern. Hydrogen sulfide (H2S), one of the three known gasotransmitters, is involved in the regulation of various cellular activities such as autophagy, apoptosis, migration, and proliferation. Low production of H2S has been identified in numerous cancer types. Treating cancer cells with H2S donors is the common experimental technique used to improve H2S levels; however, the outcome depends on the concentration/dose, time, cell type, and sometimes the drug used. Both natural and synthesized donors are available for this purpose, although their effects vary independently ranging from strong cancer suppressors to promoters. Nonetheless, numerous signaling pathways have been reported to be altered following the treatments with H2S donors which suggest their potential in cancer treatment. This review will analyze the potential of H2S donors in cancer therapy by summarizing key cellular processes and mechanisms involved.

Therapeutic Potential of Carbon Monoxide (CO) and Hydrogen Sulfide (H2S) in Hemolytic and Hemorrhagic Vascular Disorders-Interaction between the Heme Oxygenase and H2S-Producing Systems

Over the past decades, substantial work has established that hemoglobin oxidation and heme release play a pivotal role in hemolytic/hemorrhagic disorders. Recent reports have shown that oxidized hemoglobins, globin-derived peptides, and heme trigger diverse biological responses, such as toll-like receptor 4 activation with inflammatory response, reprogramming of cellular metabolism, differentiation, stress, and even death. Here, we discuss these cellular responses with particular focus on their mechanisms that are linked to the pathological consequences of hemorrhage and hemolysis. In recent years, endogenous gasotransmitters, such as carbon monoxide (CO) and hydrogen sulfide (H₂S), have gained a lot of interest in connection with various human pathologies. Thus, many CO and H₂S-releasing molecules have been developed and applied in various human disorders, including hemolytic and hemorrhagic diseases. Here, we discuss our current understanding of oxidized hemoglobin and heme-induced cell and tissue damage with particular focus on inflammation, cellular metabolism and differentiation, and endoplasmic reticulum stress in hemolytic/hemorrhagic human diseases, and the potential beneficial role of CO and H₂S in these pathologies. More detailed mechanistic insights into the complex pathology of hemolytic/hemorrhagic diseases through heme oxygenase-1/CO as well as H₂S pathways would reveal new therapeutic approaches that can be exploited for clinical benefit.

Trophoblast H2S Maintains Early Pregnancy via Regulating Maternal-Fetal Interface Immune Hemostasis

CONTEXT

Dysregulated immune hemostasis occurs in unexplained recurrent spontaneous abortion (URSA). Synthesized by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), hydrogen sulfide (H2S) promotes regulatory T-cell differentiation and regulates immune hemostasis; yet, its role in URSA is elusive.

OBJECTIVE

To determine if H2S plays a role in early pregnancy and if dysregulated H2S signaling results in recurrent spontaneous abortion.

DESIGN

First trimester placenta villi and decidua were collected from normal and URSA pregnancies. Protein expression was examined by immunohistochemistry and immunoblotting. Human trophoblast HTR8/SVneo and JEG3 cells were treated with H2S donors; HTR8/SVneo cells were transfected with CBS ribonucleic acid interference (RNAi) or complementary deoxyribonucleic acid. Cell migration and invasion were determined by transwell assays; trophoblast transcriptomes were determined by RNA sequencing (RNA-seq). Wild-type, CBS-deficient, and CBA/J × DBA/2 mice were treated with CBS and CSE inhibitors or H2S donors to determine the role of H2S in early pregnancy in vivo.

RESULTS

CBS and CSE proteins showed cell-specific expressions, but only CBS decreased in the villous cytotrophoblast in URSA versus normal participants. H2S donors promoted migration and invasion and MMP-2 and VEGF expression in human placenta trophoblast cells that contain SV40 viral deoxyribonucleic acid sequences (HTR8/SVneo) and human placenta trophoblast cells (JEG3 cells), similar to forced CBS expression in HTR8/SVneo cells. The CBS-responsive transcriptomes in HTR8/SVneo cells contained differentially regulated genes (ie, interleukin-1 receptor and prostaglandin-endoperoxide synthase 2) that are associated with nuclear factor-κB-mediated inflammatory response. In vivo, dysregulated CBS/H2S signaling significantly increased embryonic resorption and decidual T-helper 1/T-helper 2 imbalance in mice, which was partially rescued by H2S donors.

CONCLUSION

CBS/H2S signaling maintains early pregnancy, possibly via regulating maternal-fetal interface immune hemostasis, offering opportunities for H2S-based immunotherapies for URSA.

Hydrogen Sulfide Plays an Important Role by Influencing NLRP3 inflammasome

Inflammasome is a complex composed of several proteins and an important part of the natural immune system. Nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is composed of NLRP3, apoptosis associated speck like protein (ASC) and pro-caspase-1. It plays an important role in many diseases. Hydrogen sulfide (H₂S) is an important signaling molecule that regulates many physiological and pathological processes. Recent studies indicated that H₂S played anti-inflammatory and pro-inflammatory roles in many diseases through influencing NLRP3 inflammasome, but its mechanism was not fully understood. This article reviewed the progress about the effects of H₂S on NLRP3 inflammasome and its mechanisms involved in recent years to provide theoretical basis for in-depth study.

Flavonoids from Apios americana Medikus Leaves Protect RAW264.7 Cells against Inflammation via Inhibition of MAPKs, Akt-mTOR Pathways, and Nfr2 Activation

Apios americana Medikus was once widely accepted as staple food in India for a long time, and the tuber of which possesses high nutrients. During the past decades, most of the research has focused on the biological activity in the tubers of Apios americana Medikus whereas the leaves were ignored. In this study, the Apios americana Medikus leaf extract (ALE) was obtained and seven compounds were identified. LPS-induced RAW264.7 cells were used to study the anti-inflammation activity of ALE. As expected, ALE reduced the secretion of nitric oxide (NO) and inflammatory cytokines via inhibition of NF-κB and MAPK signaling together with activation of Nrf2-Keap1 and FOXO pathways, as well as alleviating the oxidative stress and mitochondrial dysfunction. In addition, ALE could activate HMGB1-Beclin1 and Sirt1-FoxO1 pathways and inhibit the Akt-mTOR signaling pathway to activate autophagy, protecting RAW264.7 cells from inflammation. In summary, our results suggested that ALE might help activate the anti-inflammation system, resulting in the prevention of LPS-induced damage in RAW264.7 cells.

Exogenous hydrogen sulfide mitigates NLRP3 inflammasome-mediated inflammation through promoting autophagy via the AMPK-mTOR pathway

The aim of this study was to investigate whether exogenous hydrogen sulfide (H₂S) could mitigate NLRP3 inflammasome-mediated inflammation through promoting autophagy via the AMPK-mTOR pathway in L02 cells. L02 cells were stimulated with different concentrations of oleic acid (OA), then cell viability and the protein expression of NLRP3 and pro-caspase-1 were detected by MTT and western blot, respectively, to determine appropriate OA concentration in this study. The cells were divided into four groups: the cells in the control group were cultured with RPMI-1640 for 24.5 h; the cells in the OA group were cultured with RPMI-1640 for 0.5 h, then were stimulated with 1.2 mmol/l OA for 24 h; the cells in the NaHS+OA group were pretreated with sodium hydrogen sulfide (NaHS, a donor of H₂S) for 0.5 h before exposure to OA for 24 h; and the cells in the NaHS group were treated with NaHS 0.5 h, then were cultured with RPMI-1640 for 24 h. Subsequently, the cells in every group were collected and the protein expression of NLRP3, procaspase-1, cleaved caspase-1, P62, LC3, Beclin1, T-AMPK, P-AMPK, T-mTOR, P-mTOR and the level of IL-1β were detected by western blot and ElISA, respectively. Exogenous H₂S reduced the level of NLRP3, caspase-1, P62, IL-1β and the ratio of P-mTOR/T-mTOR induced by OA and increased the ratio of LC3 II/I and the protein expression of Beclin1 suppressed by OA. This study demonstrates for the first time that H₂S might suppress NLRP3 inflammasome-mediated inflammation induced by OA through promoting autophagy via the AMPK-mTOR pathway. It provides a theoretical basis for the further study of the anti-inflammatory mechanism of H₂S.

Summary: We prove that exogenous H₂S can suppress NLRP3-mediated inflammation by promoting autophagy via the AMPK/mTOR pathway in L02 cells, providing insights into the anti-inflammatory mechanism of H₂S.

H 2S protects against diabetes-accelerated atherosclerosis by preventing the activation of NLRP3 inflammasome

Hydrogen sulfide (H ₂S) is an important messenger for its strong anti-inflammatory effects, which may be involved in multiple cardiovascular diseases. In our previous study, we revealed that H ₂S attenuated diabetes-accelerated atherosclerosis through suppressing oxidative stress. Here we report that GYY4137, a H ₂S donor, reduced the plaque formation of aortic roots and the levels of both intercellular cell adhesion molecule 1 (ICAM1) and vascular cell adhesion molecule 1 (VCAM1) in diabetes-accelerated atherosclerotic cells and mouse models. The inflammatory factors of TNF-α, IL-1β, IL-6, and MCP1 were also significantly reduced by GYY4137. Mechanically, GYY4137 suppressed the activation of pyrin domain containing protein 3 (NLRP3) inflammasome in diabetes-accelerated atherosclerosis conditions. Upon knockdown of NLRP3, the increase of ICAM1 and VCAM1 caused by high glucose and oxLDL could be reversed, indicating that H ₂S protected the endothelium by inhibiting the activity of NLRP3 inflammasome. In conclusion, our study indicates that GYY4137 effectively protects against the development of diabetes-accelerated atherosclerosis by inhibiting inflammasome activation.