Cystathionine-γ-lyase ameliorates the histone demethylase JMJD3-mediated autoimmune response in rheumatoid arthritis

Inhibition of EED-mediated histone methylation alleviates neuroinflammation by suppressing WNT-mediated dendritic cell migration

The epigenetic modification of histone H3 lysine 27 trimethylation (H3K27me3) by the embryonic ectoderm development (EED) protein is closely associated with the regulation of transcriptional programs and is implicated in autoimmune diseases. However, the efficacy of targeting H3K27me3 for the treatment of neuroinflammation remains unclear. In this study, we demonstrate that systemic administration of an EED inhibitor diminishes the inflammatory response mediated by dendritic cells (DCs), thereby alleviating experimental autoimmune encephalitis (EAE), a representative mouse model of autoimmune diseases in the central nervous system (CNS). Our findings indicate that EED inhibitors suppress DC migration by upregulating genes in the WNT signaling pathway that are epigenetically marked by H3K27me3. Conversely, inhibiting the WNT pathway partially reverses the impaired DC migration caused by EED inhibitors. Additionally, the genetic deletion of Eed inhibits DC migration and effectively mitigates autoimmune symptoms and inflammatory infiltration into the CNS in EAE. These results highlight EED as a critical regulator of DC migration and suggest its potential as a therapeutic target for autoimmune disorders.

NaHS@Cy5@MS@SP nanoparticles improve rheumatoid arthritis by inactivating the Hedgehog signaling pathway through sustained and targeted release of H2S into the synovium

BACKGROUND

Aberrant proliferation and inflammation of fibroblast-like synoviocytes (FLSs) significantly contribute to the pathogenesis of rheumatoid arthritis (RA). Deficiency of hydrogen sulfide (H2S) is a driving force for the development of RA, and the short half-life of the H2S-releasing donor sodium hydrosulfide (NaHS) limits its clinical application in RA therapy. Designing a targeted delivery system with slow-release properties for FLSs could offer novel strategies for treating RA.

METHODS

Herein, we designed a strategy to achieve slow release of H2S targeted to the synovium, which was accomplished by synthesizing NaHS-CY5@mesoporous silic@LNP targeted peptide Dil (NaHS@Cy5@MS@SP) nanoparticles.

RESULTS

Our results demonstrated that NaHS@Cy5@MS@SP effectively targets FLSs, upregulates H2S and its-producing enzyme cystathionine-γ-lyase (CSE) in the joints of arthritic mice. Overexpression of CSE inhibited the proliferation, migration, and inflammation of FLSs upon lipopolysaccharide (LPS) exposure, effects that were mimicked by NaHS@Cy5@MS@SP. In vivo studies showed that NaHS@Cy5@MS@SP achieved a threefold higher AUCinf than that of free NaHS, significantly improving the bioavailability of NaHS. Further, NaHS@Cy5@MS@SP inhibited synovial hyperplasia and reduced bone and cartilage erosion in the DBA/1J mouse model of collagen-induced arthritis (CIA), which was superior to NaHS. RNA sequencing and molecular studies validated that NaHS@Cy5@MS@SP inactivated the Hedgehog signaling pathway in FLSs, as evidenced by reductions in the protein expression of SHH, SMO, GLI1 and phosphorylated p38/MAPK.

CONCLUSION

This study highlights NaHS@Cy5@MS@SP as a promising strategy for the controlled and targeted delivery of H2S to synoviocytes, offering potential for RA management.

Anti-Inflammatory Effects of Hydrogen Sulfide in Axes Between Gut and Other Organs

Significance: Hydrogen sulfide (H2S), a ubiquitous small gaseous signaling molecule, plays a critical role in various diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), ischemic stroke, and myocardial infarction (MI) via reducing inflammation, inhibiting oxidative stress, and cell apoptosis. Recent Advances: Uncontrolled inflammation is closely related to pathological process of ischemic stroke, RA, MI, and IBD. Solid evidence has revealed the axes between gut and other organs like joint, brain, and heart, and indicated that H2S-mediated anti-inflammatory effect against IBD, RA, MI, and ischemic stroke might be related to regulating the functions of axes between gut and other organs. Critical Issues: We reviewed endogenous H2S biogenesis and the H2S-releasing donors, and revealed the anti-inflammatory effects of H2S in IBD, ischemic stroke, RA, and MI. Importantly, this review outlined the potential role of H2S in the gut-joint axis, gut-brain axis, and gut-heart axis as a gasotransmitter. Future Direction: The rate, location, and timing of H2S release from its donors determine its potential success or failure as a useful therapeutic agent and should be focused on in the future research. Therefore, there is still a need to explore internal and external sources monitoring and controlling H2S concentration. Moreover, more efficient H2S-releasing compounds are needed; a better understanding of their chemistry and properties should be further developed. Antioxid. Redox Signal. 42, 341-360.

Eukaryotic translation initiation factor 6-mediated ribosome biogenesis promotes synovial aggression and inflammation by increasing the translation of SP1 in rheumatoid arthritis

INTRODUCTION

Fibroblast-like synoviocytes (FLSs) play critical roles in synovial inflammation and aggression in rheumatoid arthritis (RA). Here, we explored the role of eukaryotic translation initiation factor 6 (eIF6) in regulating the biological behaviors of FLSs from patients with RA.

METHODS

FLSs were isolated from the synovial tissues of RA patients. Gene expression was assessed via RT-qPCR, and protein expression was evaluated via Western blotting or immunohistochemistry. Proliferation and nascent peptide synthesis were evaluated via EdU incorporation and HPG labeling, respectively. Cell migration and invasion were observed via Transwell assays. Polysome profiling was conducted to analyze the distribution of ribosomes and combined mRNAs. The in vivo effect of eIF6 inhibition was evaluated in a collagen-induced arthritis (CIA) rat model.

RESULTS

We found that eIF6 expression was elevated in FLSs and synovial tissues from RA patients compared to those from healthy controls and osteoarthritis patients. Knockdown of eIF6 inhibited the migration, invasion, inflammation, and proliferation of FLSs from patients with RA. Mechanistically, eIF6 knockdown downregulated ribosome biogenesis in FLSs from with RA, leading to a decrease in the proportion of polysome-associated specificity protein 1 (SP1) mRNA and a subsequent reduction in the translation initiation efficiency of SP1 mRNA. Thus, eIF6 controls SP1 expression through translation-mediated mechanisms. Interestingly, intra-articular eIF6 siRNA treatment attenuated symptoms and histological manifestations in CIA rats.

CONCLUSIONS

Our findings suggest that an increase in synovial eIF6 might contribute to rheumatoid synovial inflammation and aggression and that targeting eIF6 may have therapeutic potential in RA patients.

Emerging role of Jumonji domain-containing protein D3 in inflammatory diseases

Jumonji domain-containing protein D3 (JMJD3) is a 2-oxoglutarate-dependent dioxygenase that specifically removes transcriptional repression marks di- and tri-methylated groups from lysine 27 on histone 3 (H3K27me2/3). The erasure of these marks leads to the activation of some associated genes, thereby influencing various biological processes, such as development, differentiation, and immune response. However, comprehensive descriptions regarding the relationship between JMJD3 and inflammation are lacking. Here, we provide a comprehensive overview of JMJD3, including its structure, functions, and involvement in inflammatory pathways. In addition, we summarize the evidence supporting JMJD3's role in several inflammatory diseases, as well as the potential therapeutic applications of JMJD3 inhibitors. Additionally, we also discuss the challenges and opportunities associated with investigating the functions of JMJD3 and developing targeted inhibitors and propose feasible solutions to provide valuable insights into the functional exploration and discovery of potential drugs targeting JMJD3 for inflammatory diseases.

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.

α-Ketoglutarate-Dependent KDM6 Histone Demethylases and Interferon-Stimulated Gene Expression in Lupus

OBJECTIVE

We aimed to investigate the hypothesis that interferon (IFN)-stimulated gene (ISG) expression in systemic lupus erythematosus (SLE) monocytes is linked to changes in metabolic reprogramming and epigenetic regulation of ISG expression.

METHODS

Monocytes from healthy volunteers and patients with SLE at baseline or following IFNα treatment were analyzed by extracellular flux analysis, proteomics, metabolomics, chromatin immunoprecipitation, and gene expression. The histone demethylases KDM6A/B were inhibited using glycogen synthase kinase J4 (GSK-J4). GSK-J4 was tested in pristane and resiquimod (R848) models of IFN-driven SLE.

RESULTS

SLE monocytes had enhanced rates of glycolysis and oxidative phosphorylation compared to healthy control monocytes, as well as increased levels of isocitrate dehydrogenase and its product, α-ketoglutarate (α-KG). Because α-KG is a required cofactor for histone demethylases KDM6A and KDM6B, we hypothesized that IFNα may be driving "trained immune" responses through altering histone methylation. IFNα priming (day 1) resulted in a sustained increase in the expression of ISGs in primed cells (day 5) and enhanced expression on restimulation with IFNα. Importantly, decreased H3K27 trimethylation was observed at the promoters of ISGs following IFNα priming. Finally, GSK-J4 (KDM6A/B inhibitor) resulted in decreased ISG expression in SLE patient monocytes, as well as reduced autoantibody production, ISG expression, and kidney pathology in R848-treated BALB/c mice.

CONCLUSION

Our study suggests long-term IFNα exposure alters the epigenetic regulation of ISG expression in SLE monocytes via changes in immunometabolism, a mechanism reflecting trained immunity to type I IFN. Importantly, it opens the possibility that targeting histone-modifying enzymes, such as KDM6A/B, may reduce IFN responses in SLE.

Rheumatoid arthritis: pathogenesis and therapeutic advances

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the unresolved synovial inflammation for tissues-destructive consequence, which remains one of significant causes of disability and labor loss, affecting about 0.2-1% global population. Although treatments with disease-modifying antirheumatic drugs (DMARDs) are effective to control inflammation and decrease bone destruction, the overall remission rates of RA still stay at a low level. Therefore, uncovering the pathogenesis of RA and expediting clinical transformation are imminently in need. Here, we summarize the immunological basis, inflammatory pathways, genetic and epigenetic alterations, and metabolic disorders in RA, with highlights on the abnormality of immune cells atlas, epigenetics, and immunometabolism. Besides an overview of first-line medications including conventional DMARDs, biologics, and small molecule agents, we discuss in depth promising targeted therapies under clinical or preclinical trials, especially epigenetic and metabolic regulators. Additionally, prospects on precision medicine based on synovial biopsy or RNA-sequencing and cell therapies of mesenchymal stem cells or chimeric antigen receptor T-cell are also looked forward. The advancements of pathogenesis and innovations of therapies in RA accelerates the progress of RA treatments.

YAP represses intestinal inflammation through epigenetic silencing of JMJD3

BACKGROUND

Epigenetics plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Some studies have reported that YAP is involved in inflammatory response and can regulate target genes through epigenetic modifications. JMJD3, a histone H3K27me3 demethylase, is associated with some inflammatory diseases. In this study, we investigated the role of YAP in the development of IBD and the underlying epigenetic mechanisms.

RESULTS

YAP expression was significantly increased in both in vitro and in vivo colitis models as well as in patients with IBD. Epithelial-specific knockout of YAP aggravates disease progression in dextran sodium sulfate (DSS)-induced murine colitis. In the TNF-α-activated cellular inflammation model, YAP knockdown significantly increased JMJD3 expression. Coimmunoprecipitation experiments showed that YAP and EZH2 bind to each other, and chromatin immunoprecipitation-PCR (ChIP-PCR) assay indicated that silencing of YAP or EZH2 decreases H3K27me3 enrichment on the promoter of JMJD3. Finally, administration of the JMJD3 pharmacological inhibitor GSK-J4 alleviated the progression of DSS-induced murine colitis.

CONCLUSION

Our findings elucidate an epigenetic mechanism by which YAP inhibits the inflammatory response in colitis through epigenetic silencing of JMJD3 by recruiting EZH2.

Hydrogen Sulfide and Functional Therapy: Novel Mechanisms from Epigenetics

Hydrogen sulfide (H2S) is a gasotransmitter with significant physiological effects, including anti-inflammatory properties, regulation of oxidative stress, and vasodilation, thus regulating body functions. Functional therapy involves using treatments that target the underlying cause of a disease, rather than simply treating symptoms. Epigenetics refers to changes in gene expression that occur through modifications to DNA, to the proteins that package DNA, or to noncoding RNA mechanisms. Recent research advances suggest that H2S may play a role in epigenetic regulation by altering DNA methylation patterns and regulating histone deacetylases, enzymes that modify histone proteins, or modulating microRNA mechanisms. These critical findings suggest that H2S may be a promising molecule for functional therapy in various diseases where epigenetic modifications are dysregulated. We reviewed the relevant research progress in this area, hoping to provide new insights into the epigenetic mechanisms of H2S. Despite the challenges of clinical use of H2S, future research may lead to the progress of new therapeutic approaches. Antioxid. Redox Signal. 40, 110-121.

Epigenetic and transcriptional regulation of CCL17 production by glucocorticoids in arthritis

Glucocorticoids (GCs) are potent anti-inflammatory agents and are broadly used in treating rheumatoid arthritis (RA) patients, albeit with adverse side effects associated with long-term usage. The negative consequences of GC therapy provide an impetus for research into gaining insights into the molecular mechanisms of GC action. We have previously reported that granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced CCL17 has a non-redundant role in inflammatory arthritis. Here, we provide molecular evidence that GCs can suppress GM-CSF-mediated upregulation of IRF4 and CCL17 expression via downregulating JMJD3 expression and activity. In mouse models of inflammatory arthritis, GC treatment inhibited CCL17 expression and ameliorated arthritic pain-like behavior and disease. Significantly, GC treatment of RA patient peripheral blood mononuclear cells ex vivo resulted in decreased CCL17 production. This delineated pathway potentially provides new therapeutic options for the treatment of many inflammatory conditions, where GCs are used as an anti-inflammatory drug but without the associated adverse side effects.

Rheumatoid Arthritis Has Won the Battle but Not the War: How Many Joints Will We Save Tomorrow?

Rheumatoid arthritis refers to joint diseases of unclear etiology whose final stages can lead to unbearable pain and complete immobility of the affected joints. As one of the most widely known diseases of the joints, it serves as a study target for a large number of research groups and pharmaceutical companies. Modern treatment with anti-inflammatory drugs, including janus kinase (JAK) inhibitors, monoclonal antibodies, and botanicals (polyphenols, glycosides, alkaloids, etc.) has achieved some success and hope for improving the course of the disease. However, existing drugs against RA have a number of side effects which push researchers to elaborate on more selective and effective drug candidates. The avant-garde of research, which aims to develop treatment of rheumatoid arthritis using antisense oligonucleotides along with nonsteroidal drugs and corticosteroids against inflammation, increases the chances of success and expands the arsenal of drugs. The primary goal in the treatment of this disease is to find therapies that allow patients with rheumatoid arthritis to move their joints without pain. The main purpose of this review is to show the victories and challenges for the treatment of rheumatoid arthritis and the tortuous but promising path of research that aims to help patients experience the joy of freely moving joints without pain.

Innate immune memory in inflammatory arthritis

The concept of immunological memory was demonstrated in antiquity when protection against re-exposure to pathogens was observed during the plague of Athens. Immunological memory has been linked with the adaptive features of T and B cells; however, in the past decade, evidence has demonstrated that innate immune cells can exhibit memory, a phenomenon called 'innate immune memory' or 'trained immunity'. Innate immune memory is currently being defined and is transforming our understanding of chronic inflammation and autoimmunity. In this Review, we provide an up-to-date overview of the memory-like features of innate immune cells in inflammatory arthritis and the crosstalk between chronic inflammatory milieu and cell reprogramming. Aberrant pro-inflammatory signalling, including cytokines, regulates the metabolic and epigenetic reprogramming of haematopoietic progenitors, leading to exacerbated inflammatory responses and osteoclast differentiation, in turn leading to bone destruction. Moreover, imprinted memory on mature cells including terminally differentiated osteoclasts alters responsiveness to therapies and modifies disease outcomes, commonly manifested by persistent inflammatory flares and relapse following medication withdrawal.

JMJD3 ablation in myeloid cells confers renoprotection in mice with DOCA/salt-induced hypertension

Hypertension-induced renal injury is characterized by robust inflammation and tubulointerstitial fibrosis. Jumonji domain containing-3 (JMJD3) is closely linked with inflammatory response and fibrogenesis. Here we examined the effect of myeloid JMJD3 ablation on kidney inflammation and fibrosis in deoxycorticosterone acetate (DOCA)/salt hypertension. Our results showed that JMJD3 is notably induced in the kidneys with hypertensive injury. DOCA/salt stress causes an elevation in blood pressure that was no difference between myeloid specific JMJD3-deficient mice and wild-type control mice. Compared with wild-type control mice, myeloid JMJD3 ablation ameliorated kidney function and injury of mice in response to DOCA/salt challenge. Myeloid JMJD3 ablation attenuated collagen deposition, extracellular matrix proteins expression, and fibroblasts activation in injured kidneys following DOCA/salt treatment. Furthermore, myeloid JMJD3 ablation blunts inflammatory response in injured kidneys after DOCA/salt stress. Finally, myeloid JMJD3 ablation precluded myeloid myofibroblasts activation and protected against macrophages to myofibroblasts transition in injured kidneys. These beneficial effects were accompanied by reduced expression of interferon regulator factor 4. In summary, JMJD3 ablation in myeloid cells reduces kidney inflammation and fibrosis in DOCA salt-induced hypertension. Inhibition of myeloid JMJD3 may be a novel potential therapeutic target for hypertensive nephropathy. Myeloid JMJD3 deficiency reduces inflammatory response, myeloid fibroblasts activation, macrophages to myofibroblasts transition, and delays kidney fibrosis progression.

Hydrogen sulfide and epigenetics: Novel insights into the cardiovascular effects of this gasotransmitter

Epigenetics studies the heritable modifications of genome expression that do not affect the nucleotide sequence. Epigenetic modifications can be divided into: DNA methylation, histone modifications, and modulation of genome expression by non-coding RNAs. Alteration of these mechanisms can alter the phenotype, and can lead to disease onset. The endogenous gasotransmitter hydrogen sulfide (H2 S) plays pleiotropic roles in many systems, including the cardiovascular (CV) system, and its mechanism of action mainly includes S-persulfidation of cysteine residues. Recent evidence suggests that many H2 S-mediated biological activities are based on the epigenetic regulation of cellular function, with effects ranging from DNA methylation to modification of histones and regulation of non-coding RNAs. This review describes the role of H2 S-regulating epigenetic mechanisms, providing a panorama of the current literature, and offers a novel scenario for the development of H2 S-releasing 'epidrugs' with a potential clinical use in the prevention and treatment of many CV and non-CV disorders.

Histone demethylases in the regulation of immunity and inflammation

Pathogens or danger signals trigger the immune response. Moderate immune response activation removes pathogens and avoids excessive inflammation and tissue damage. Histone demethylases (KDMs) regulate gene expression and play essential roles in numerous physiological processes by removing methyl groups from lysine residues on target proteins. Abnormal expression of KDMs is closely associated with the pathogenesis of various inflammatory diseases such as liver fibrosis, lung injury, and autoimmune diseases. Despite becoming exciting targets for diagnosing and treating these diseases, the role of these enzymes in the regulation of immune and inflammatory response is still unclear. Here, we review the underlying mechanisms through which KDMs regulate immune-related pathways and inflammatory responses. In addition, we also discuss the future applications of KDMs inhibitors in immune and inflammatory diseases.

Bioinformatic analyzes and validation of cystathionine gamma-lyase as a prognostic biomarker and related to immune infiltrates in hepatocellular carcinoma

Background

The role of cystathionine γ-lyase (CTH) in the prognosis and immune invasion of hepatocellular carcinoma (HCC) remains poorly understood.

Methods

In this study, the clinical data of patients with HCC were analyzed, and the expression level of CTH was compared between HCC and normal tissues using the R package and various databases.

Results

We found that CTH expression was significantly decreased in HCC compared with normal tissues, and its expression was associated with various clinicopathological factors, including tumor stage, gender, tumor status, residual tumor, histologic stage, race, alpha-fetoprotein (AFP), albumin, drinking, and smoking. Our results suggest that CTH might be a protective factor for the survival of patients with HCC. Further functional analysis revealed that high CTH expression was enriched in the Reactome signaling by interleukins and the Reactome neutrophil degranulation. Moreover, CTH expression was closely correlated with a variety of immune cells, including a negative correlation with the CD56 (bright) NK cells and follicular helper T cell (TFH), while a positive correlation with Th17 cells and central memory T cell (Tcm). High expression of CTH in immune cells predicted a better prognosis of HCC. Our findings further indicated Pyridoxal phosphate, l-cysteine, Carboxymethylthio-3-(3-chlorophenyl)-1,2,4-oxadiazol, 2-[(3-Hydroxy-2-Methyl-5-Phosphonooxymethyl-Pyridin-4-Ylmethyl)-Imino]-5-phosphono-pent-3-enoic acid and L-2-amino-3-butynoic acid as potential target candidate medications for HCC treatment based on CTH.

Conclusion

Our study suggests that CTH can serve as a biomarker to predict the prognosis and immune infiltration of HCC.

New Targets and Strategies for Rheumatoid Arthritis: From Signal Transduction to Epigenetic Aspect

Rheumatoid arthritis (RA) is a chronic autoimmune disease that can lead to joint damage and even permanent disability, seriously affecting patients' quality of life. At present, the complete cure for RA is not achievable, only to relieve the symptoms to reduce the pain of patients. Factors such as environment, genes, and sex can induce RA. Presently, non-steroidal anti-inflammatory drugs, DRMADs, and glucocorticoids are commonly used in treating RA. In recent years, some biological agents have also been applied in clinical practice, but most have side effects. Therefore, finding new mechanisms and targets for treating RA is necessary. This review summarizes some potential targets discovered from the perspective of epigenetics and RA mechanisms.

Signaling pathways in rheumatoid arthritis: implications for targeted therapy

Rheumatoid arthritis (RA) is an incurable systemic autoimmune disease. Disease progression leads to joint deformity and associated loss of function, which significantly impacts the quality of life for sufferers and adds to losses in the labor force. In the past few decades, RA has attracted increased attention from researchers, the abnormal signaling pathways in RA are a very important research field in the diagnosis and treatment of RA, which provides important evidence for understanding this complex disease and developing novel RA-linked intervention targets. The current review intends to provide a comprehensive overview of RA, including a general introduction to the disease, historical events, epidemiology, risk factors, and pathological process, highlight the primary research progress of the disease and various signaling pathways and molecular mechanisms, including genetic factors, epigenetic factors, summarize the most recent developments in identifying novel signaling pathways in RA and new inhibitors for treating RA. therapeutic interventions including approved drugs, clinical drugs, pre-clinical drugs, and cutting-edge therapeutic technologies. These developments will hopefully drive progress in new strategically targeted therapies and hope to provide novel ideas for RA treatment options in the future.

Reduced Renal CSE/CBS/H2S Contributes to the Progress of Lupus Nephritis

The molecular mechanisms underlying lupus nephritis (LN) pathogenesis are not fully understood. Hydrogen sulfide (H2S) is involved in many pathological and physiological processes. We sought to investigate the roles of H2S in LN pathogenesis. H2S synthase cystathionine-lyase (CSE) and cystathionine-synthetase (CBS) expression was downregulated in renal tissues of patients with LN and their levels were associated with LN's prognosis using the Nephroseq database. Reduced CSE and CBS protein expression in kidney tissues of LN patients and MRL/lpr mice were confirmed by immunohistochemistry. CSE and CBS mRNA levels were reduced in MRL/lpr and pristine- and R848-induced lupus mice. Given that H2S exerts an anti-inflammatory role partly via regulating inflammatory transcription factors (TFs), we analyzed hub TFs by using a bioinformatics approach. It showed that STAT1, RELA, and T-cell-related signaling pathways were enriched in LN. Increased STAT1 and RELA expression were confirmed in renal tissues of LN patients. Treatment of MRL/lpr and pristine mice with H2S donors alleviated systemic lupus erythematosus (SLE) phenotypes and renal injury. H2S donors inhibited RELA level and T-cell infiltration in the kidneys of MRL/lpr and pristine mice. Our data indicated that CSE/CBS/H2S contributes to LN pathogenesis. Supplementation of H2S would be a potential therapeutic strategy for LN.

Role of Jumonji domain-containing protein D3 and its inhibitor GSK-J4 in Hashimoto's thyroiditis

Hashimoto's thyroiditis (HT) is an autoimmune illness caused by a combination of genetic, epigenetic, and environmental factors. The pathogenesis of HT is not fully elucidated, especially in epigenetics. The epigenetic regulator Jumonji domain-containing protein D3 (JMJD3) has been extensively investigated in immunological disorders. This study has been performed to explore the roles and potential mechanisms of JMJD3 in HT. Thyroid samples from patients and healthy subjects were collected. We first analyzed the expression of JMJD3 and chemokines in the thyroid gland using real-time PCR and immunohistochemistry. In vitro, the apoptosis effect of the JMJD3-specific inhibitor GSK-J4 on the thyroid epithelial cell line Nthy-ori 3-1 was evaluated using FITC Annexin V Detection kit. Reverse transcription-polymerase chain reaction and Western blotting were applied to examine the inhibitory effect of GSK-J4 on the inflammation of thyrocytes. In the thyroid tissue of HT patients, JMJD3 messenger RNA and protein levels were substantially greater than in controls (P < 0.05). Chemokines C-X-C motif chemokine ligand 10 (CXCL10) and C-C motif chemokine ligand 2 (CCL2) were elevated in HT patients, and thyroid cells with stimulation of tumor necrosis factor α (TNF-α). GSK-J4 could suppress TNF-α-induced synthesis of chemokines CXCL10 and CCL2 and prohibit thyrocyte apoptosis. Our results shed light on the potential role of JMJD3 in HT and indicate that JMJD3 may become a novel therapeutic target in HT treatment and prevention.

Hydrogen Sulfide Biomedical Research in China-20 Years of Hindsight

Hydrogen sulfide (H2S) is an important gasotransmitter that is produced by mammalian cells and performs profound physiological and pathophysiological functions. Biomedical research on H2S metabolism and function in China began 20 years ago, which pioneered the examination of the correlation of abnormal H2S metabolism and cardiovascular diseases. Over the last two decades, research teams in China have made numerous breakthrough discoveries on the effects of H2S metabolism on hypertension, atherosclerosis, pulmonary hypertension, shock, angiogenesis, chronic obstructive pulmonary disease, pain, iron homeostasis, and testicle function, to name a few. These research developments, carried by numerous research teams all over China, build nationwide research network and advance both laboratory study and clinical applications. An integrated and collaborative research strategy would further promote and sustain H2S biomedical research in China and in the world.

JMJD family proteins in cancer and inflammation

The occurrence of cancer entails a series of genetic mutations that favor uncontrollable tumor growth. It is believed that various factors collectively contribute to cancer, and there is no one single explanation for tumorigenesis. Epigenetic changes such as the dysregulation of enzymes modifying DNA or histones are actively involved in oncogenesis and inflammatory response. The methylation of lysine residues on histone proteins represents a class of post-translational modifications. The human Jumonji C domain-containing (JMJD) protein family consists of more than 30 members. The JMJD proteins have long been identified with histone lysine demethylases (KDM) and histone arginine demethylases activities and thus could function as epigenetic modulators in physiological processes and diseases. Importantly, growing evidence has demonstrated the aberrant expression of JMJD proteins in cancer and inflammatory diseases, which might serve as an underlying mechanism for the initiation and progression of such diseases. Here, we discuss the role of key JMJD proteins in cancer and inflammation, including the intensively studied histone lysine demethylases, as well as the understudied group of JMJD members. In particular, we focused on epigenetic changes induced by each JMJD member and summarized recent research progress evaluating their therapeutic potential for the treatment of cancer and inflammatory diseases.

Histone demethylase JMJD3 downregulation protects against aberrant force-induced osteoarthritis through epigenetic control of NR4A1

Osteoarthritis (OA) is a prevalent joint disease with no effective treatment strategies. Aberrant mechanical stimuli was demonstrated to be an essential factor for OA pathogenesis. Although multiple studies have detected potential regulatory mechanisms underlying OA and have concentrated on developing novel treatment strategies, the epigenetic control of OA remains unclear. Histone demethylase JMJD3 has been reported to mediate multiple physiological and pathological processes, including cell differentiation, proliferation, autophagy, and apoptosis. However, the regulation of JMJD3 in aberrant force-related OA and its mediatory effect on disease progression are still unknown. In this work, we confirmed the upregulation of JMJD3 in aberrant force-induced cartilage injury in vitro and in vivo. Functionally, inhibition of JMJD3 by its inhibitor, GSK-J4, or downregulation of JMJD3 by adenovirus infection of sh-JMJD3 could alleviate the aberrant force-induced chondrocyte injury. Mechanistic investigation illustrated that aberrant force induces JMJD3 expression and then demethylates H3K27me3 at the NR4A1 promoter to promote its expression. Further experiments indicated that NR4A1 can regulate chondrocyte apoptosis, cartilage degeneration, extracellular matrix degradation, and inflammatory responses. In vivo, anterior cruciate ligament transection (ACLT) was performed to construct an OA model, and the therapeutic effect of GSK-J4 was validated. More importantly, we adopted a peptide-siRNA nanoplatform to deliver si-JMJD3 into articular cartilage, and the severity of joint degeneration was remarkably mitigated. Taken together, our findings demonstrated that JMJD3 is flow-responsive and epigenetically regulates OA progression. Our work provides evidences for JMJD3 inhibition as an innovative epigenetic therapy approach for joint diseases by utilizing p5RHH-siRNA nanocomplexes.

Physiological roles of hydrogen sulfide in mammalian cells, tissues and organs

H2S belongs to the class of molecules known as gasotransmitters, which also includes nitric oxide (NO) and carbon monoxide (CO). Three enzymes are recognized as endogenous sources of H2S in various cells and tissues: cystathionine g-lyase (CSE), cystathionine β-synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current article reviews the regulation of these enzymes as well as the pathways of their enzymatic and non-enzymatic degradation and elimination. The multiple interactions of H2S with other labile endogenous molecules (e.g. NO) and reactive oxygen species are also outlined. The various biological targets and signaling pathways are discussed, with special reference to H2S and oxidative posttranscriptional modification of proteins, the effect of H2S on channels and intracellular second messenger pathways, the regulation of gene transcription and translation and the regulation of cellular bioenergetics and metabolism. The pharmacological and molecular tools currently available to study H2S physiology are also reviewed, including their utility and limitations. In subsequent sections, the role of H2S in the regulation of various physiological and cellular functions is reviewed. The physiological role of H2S in various cell types and organ systems are overviewed. Finally, the role of H2S in the regulation of various organ functions is discussed as well as the characteristic bell-shaped biphasic effects of H2S. In addition, key pathophysiological aspects, debated areas, and future research and translational areas are identified A wide array of significant roles of H2S in the physiological regulation of all organ functions emerges from this review.

Inhibition of Histone H3 Lysine-27 Demethylase Activity Relieves Rheumatoid Arthritis Symptoms via Repression of IL6 Transcription in Macrophages

Rheumatoid arthritis (RA) occurs in about 5 per 1,000 people and can lead to severe joint damage and disability. However, the knowledge of pathogenesis and treatment for RA remains limited. Here, we found that histone demethylase inhibitor GSK-J4 relieved collagen induced arthritis (CIA) symptom in experimental mice model, and the underlying mechanism is related to epigenetic transcriptional regulation in macrophages. The role of epigenetic regulation has been introduced in the process of macrophage polarization and the pathogenesis of inflammatory diseases. As a repressive epigenetic marker, tri-methylation of lysine 27 on histone H3 (H3K27me3) was shown to be important for transcriptional gene expression regulation. Here, we comprehensively analyzed H3K27me3 binding promoter and corresponding genes function by RNA sequencing in two differentially polarized macrophage populations. The results revealed that H3K27me3 binds on the promoter regions of multiple critical cytokine genes and suppressed their transcription, such as IL6, specifically in M-CSF derived macrophages but not GM-CSF derived counterparts. Our results may provide a new approach for the treatment of inflammatory and autoimmune disorders.

Epigenetic Regulation in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease. The etiology of RA remains undetermined and the pathogenesis is complex. There remains a paucity of ideal therapeutic drugs and treatment strategies. The epigenetic modifications affect and regulate the function and characteristics of genes through mechanisms, including DNA methylation, histone modification, chromosome remodeling, and RNAi, thereby exerting a significant impact on the living state of the body. Recently, the phenomenon of epigenetic modification in RA has garnered growing research interest. The application of epigenetically modified methods is the frontier field in the research of RA pathogenesis. This review highlights the research on the pathogenesis of RA based on epigenetic modification in the recent five years, thereby suggesting new methods and strategies for the diagnosis and treatment of RA.

Overexpression of CBS/H2S inhibits proliferation and metastasis of colon cancer cells through downregulation of CD44

Background

The role of hydrogen sulfide (H₂S) in cancer biology is controversial, including colorectal cancer. The bell-shaped effect of H₂S refers to pro-cancer action at lower doses and anti-cancer effect at higher concentrations. We hypothesized that overexpression of cystathionine-beta-synthase (CBS)/H₂S exerts an inhibitory effect on colon cancer cell proliferation and metastasis.

Methods

Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8), clone-formation and sphere formation assay. Cell migration was evaluated by transwell migration assay. Intracellular H₂S was detected by H₂S probe. Chromatin immunoprecipitation (ChIP) analysis was carried out to examine DNA–protein interaction. Cell experiments also included western blotting, flow cytometry, immunohistochemistry (IHC) and immunofluorescence analysis. We further conducted in vivo experiments to confirm our conclusions.

Results

Overexpression of CBS and exogenous H₂S inhibited colon cancer cell proliferation and migration in vitro. In addition, overexpression of CBS attenuated tumor growth and liver metastasis in vivo. Furthermore, CD44 and the transcription factor SP-1 was probably involved in the inhibitory effect of CBS/H₂S axis on colon cancer cells.

Conclusions

Overexpression of CBS and exogenous provision of H₂S inhibited colon cancer cell proliferation and migration both in vivo and in vitro. Molecular mechanisms might involve the participation of CD44 and the transcription factor SP-1.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02512-2.

Buffering Adaptive Immunity by Hydrogen Sulfide

T cell-mediated adaptive immunity is designed to respond to non-self antigens and pathogens through the activation and proliferation of various T cell populations. T helper 1 (Th1), Th2, Th17 and Treg cells finely orchestrate cellular responses through a plethora of paracrine and autocrine stimuli that include cytokines, autacoids, and hormones. Hydrogen sulfide (H₂S) is one of these mediators able to induce/inhibit immunological responses, playing a role in inflammatory and autoimmune diseases, neurological disorders, asthma, acute pancreatitis, and sepsis. Both endogenous and exogenous H₂S modulate numerous important cell signaling pathways. In monocytes, polymorphonuclear, and T cells H₂S impacts on activation, survival, proliferation, polarization, adhesion pathways, and modulates cytokine production and sensitivity to chemokines. Here, we offer a comprehensive review on the role of H₂S as a natural buffer able to maintain over time a functional balance between Th1, Th2, Th17 and Treg immunological responses.

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.

Nitric oxide and hydrogen sulfide: Sibling rivalry in the family of epigenetic regulators

Nitric oxide (NO) and hydrogen sulfide (H₂S) were previously only known for their toxic properties. Now they are regarded as potent gaseous messenger molecules (gasotransmitters) that rapidly transverse cell membranes and transduce cellular signals through their chemical reactions and modifications to protein targets. Both are known to regulate numerous physiological functions including angiogenesis, vascular tone, and immune response, to name a few. NO and H₂S often work synergistically and in competition to regulate each other's synthesis, target protein activity via posttranslational modifications (PTMs), and chemical interactions. In addition to their canonical modes of action, increasing evidence has demonstrated that NO and H₂S share another signaling mechanism: epigenetic regulation. This review will compare and contrast biosynthesis and metabolism of NO and H₂S, their individual and shared interactions, and the growing body of evidence for their roles as endogenous epigenetic regulatory molecules.

The Preparation of a Novel Poly(Lactic Acid)-Based Sustained H2S Releasing Microsphere for Rheumatoid Arthritis Alleviation

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease that mainly erodes joints and surrounding tissues, and if it is not treated in time, it can cause joint deformities and loss of function. S-propargyl-cysteine (SPRC) is an excellent endogenous hydrogen sulfide donor which can relieve the symptoms of RA through the promotion of H2S release via the CSE/H2S pathway in vivo. However, the instant release of H2S in vivo could potentially limit its further clinical use. To solve this problem, in this study, a SPRC-loaded poly(lactic acid) (PLA) microsphere (SPRC@PLA) was prepared, which could release SPRC in vitro in a sustained manner, and further promote sustained in vivo H2S release. Furthermore, its therapeutical effect on RA in rats was also studied. A spherical-like SPRC@PLA was successfully prepared with a diameter of approximately 31.61 μm, yielding rate of 50.66%, loading efficiency of 6.10% and encapsulation efficiency of 52.71%. The SPRC@PLA showed significant prolonged in vitro SPRC release, to 4 days, and additionally, an in vivo H2S release around 3 days could also be observed. In addition, a better therapeutical effect and prolonged administration interval toward RA rats was also observed in the SPRC@PLA group.

The demethylase inhibitor GSK-J4 limits inflammatory colitis by promoting de novo synthesis of retinoic acid in dendritic cells

Dendritic cells (DCs) promote T-cell mediated tolerance to self-antigens and induce inflammation to innocuous-antigens. This dual potential makes DCs fundamental players in inflammatory disorders. Evidence from inflammatory colitis mouse models and inflammatory bowel diseases (IBD) patients indicated that gut inflammation in IBD is driven mainly by T-helper-1 (Th1) and Th17 cells, suggesting an essential role for DCs in the development of IBD. Here we show that GSK-J4, a selective inhibitor of the histone demethylase JMJD3/UTX, attenuated inflammatory colitis by reducing the inflammatory potential and increasing the tolerogenic features of DCs. Mechanistic analyses revealed that GSK-J4 increased activating epigenetic signals while reducing repressive marks in the promoter of retinaldehyde dehydrogenase isoforms 1 and 3 in DCs, enhancing the production of retinoic acid. This, in turn, has an impact on regulatory T cells (Treg) increasing their lineage stability and gut tropism as well as potentiating their suppressive activity. Our results open new avenues for the treatment of IBD patients.

microRNA-27b shuttled by mesenchymal stem cell-derived exosomes prevents sepsis by targeting JMJD3 and downregulating NF-κB signaling pathway

Background

Exosomal microRNAs (miRs) derived from mesenchymal stem cells (MSCs) have been shown to play roles in the pathophysiological processes of sepsis. Moreover, miR-27b is highly enriched in MSC-derived exosomes. Herein, we aimed to investigate the potential role and downstream molecular mechanism of exosomal miR-27b in sepsis.

Methods

Inflammation was induced in bone marrow-derived macrophages (BMDMs) by lipopolysaccharide (LPS), and mice were made septic by cecal ligation and puncture (CLP). The expression pattern of miR-27b in MSC-derived exosomes was characterized using RT-qPCR, and its downstream gene was predicted by in silico analysis. The binding affinity between miR-27b, Jumonji D3 (JMJD3), or nuclear factor κB (NF-κB) was characterized to identify the underlying mechanism. We induced miR-27b overexpression or downregulation, along with silencing of JMJD3 or NF-κB to examine their effects on sepsis. The production of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 was detected by ELISA.

Results

miR-27b was highly expressed in MSC-derived exosomes. Mechanistic investigations showed that miR-27b targeted JMJD3. miR-27b decreased expression of pro-inflammatory genes by inhibiting the recruitment of JMJD3 and NF-κB at gene promoter region. Through this, MSC-derived exosomal miR-27b diminished production of pro-inflammatory cytokines in LPS-treated BMDMs and septic mice, which could be rescued by upregulation of JMJD3 and NF-κB. Besides, in vitro findings were reproduced by in vivo findings.

Conclusion

These data demonstrated that exosomal miR-27b derived from MSCs inhibited the development of sepsis by downregulating JMJD3 and inactivating the NF-κB signaling pathway.

Epigenetics and Vascular Senescence-Potential New Therapeutic Targets?

Epigenetics is defined as the heritable alterations of gene expression without changes to the coding sequence of DNA. These alterations are mediated by processes including DNA methylation, histone modifications, and non-coding RNAs mechanisms. Vascular aging consists of both structural and functional changes in the vasculature including pathological processes that drive progression such as vascular cell senescence, inflammation, oxidation stress, and calcification. As humans age, these pathological conditions gradually accumulate, driven by epigenetic alterations, and are linked to various aging-related diseases. The development of drugs targeting a spectrum of epigenetic processes therefore offers novel treatment strategies for the targeting of age-related diseases. In our previous studies, we identified HDAC4, JMJD3, Fra-1, and GATA4 as potential pharmacological targets for regulating vascular inflammation, injury, and senescence.

Hydrogen sulfide: An endogenous regulator of the immune system

Hydrogen sulfide (H₂S) is now recognized as an endogenous signaling gasotransmitter in mammals. It is produced by mammalian cells and tissues by various enzymes - predominantly cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) - but part of the H₂S is produced by the intestinal microbiota (colonic H₂S-producing bacteria). Here we summarize the available information on the production and functional role of H₂S in the various cell types typically associated with innate immunity (neutrophils, macrophages, dendritic cells, natural killer cells, mast cells, basophils, eosinophils) and adaptive immunity (T and B lymphocytes) under normal conditions and as it relates to the development of various inflammatory and immune diseases. Special attention is paid to the physiological and the pathophysiological aspects of the oral cavity and the colon, where the immune cells and the parenchymal cells are exposed to a special "H₂S environment" due to bacterial H₂S production. H₂S has many cellular and molecular targets. Immune cells are "surrounded" by a "cloud" of H₂S, as a result of endogenous H₂S production and exogenous production from the surrounding parenchymal cells, which, in turn, importantly regulates their viability and function. Downregulation of endogenous H₂S producing enzymes in various diseases, or genetic defects in H₂S biosynthetic enzyme systems either lead to the development of spontaneous autoimmune disease or accelerate the onset and worsen the severity of various immune-mediated diseases (e.g. autoimmune rheumatoid arthritis or asthma). Low, regulated amounts of H₂S, when therapeutically delivered by small molecule donors, improve the function of various immune cells, and protect them against dysfunction induced by various noxious stimuli (e.g. reactive oxygen species or oxidized LDL). These effects of H₂S contribute to the maintenance of immune functions, can stimulate antimicrobial defenses and can exert anti-inflammatory therapeutic effects in various diseases.

Epigenetic Regulation Mediated by Methylation in the Pathogenesis and Precision Medicine of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a complex disease triggered by the interaction between genetics and the environment, especially through the shared epitope (SE) and cell surface calreticulin (CSC) theory. However, the available evidence shows that genetic diversity and environmental exposure cannot explain all the clinical characteristics and heterogeneity of RA. In contrast, recent studies demonstrate that epigenetics play important roles in the pathogenesis of RA, especially DNA methylation and histone modification. DNA methylation and histone methylation are involved in innate and adaptive immune cell differentiation and migration, proliferation, apoptosis, and mesenchymal characteristics of fibroblast-like synoviocytes (FLS). Epigenetic-mediated regulation of immune-related genes and inflammation pathways explains the dynamic expression network of RA. In this review, we summarize the comprehensive evidence to show that methylation of DNA and histones is significantly involved in the pathogenesis of RA and could be applied as a promising biomarker in the disease progression and drug-response prediction. We also explain the advantages and challenges of the current epigenetics research in RA. In summary, epigenetic modules provide a possible interface through which genetic and environmental risk factors connect to contribute to the susceptibility and pathogenesis of RA. Additionally, epigenetic regulators provide promising drug targets to develop novel therapeutic drugs for RA. Finally, DNA methylation and histone modifications could be important features for providing a better RA subtype identification to accelerate personalized treatment and precision medicine.

Endothelial progenitor cells-secreted extracellular vesicles containing microRNA-93-5p confer protection against sepsis-induced acute kidney injury via the KDM6B/H3K27me3/TNF-α axis

The pivotal pathogenetic role of microRNAs (miRs) in sepsis-induced acute kidney injury (AKI) has been demonstrated in mounting evidence. The functions of the target cells are regulated through the release of cells-encapsulated extracellular vesicles (Evs) into the extracellular space. The present study aims to elucidate the clinical significance as well as biological function of the endothelial progenitor cell (EPC)-derived Evs containing miR-93-5p in sepsis-induced AKI. We first established a cellular sepsis-induced AKI mouse model by treatment with lipopolysaccharide (LPS), and tested ectopic expression and depletion experiments in the model. Evs derived from miR-93-5p inhibitor-transfected EPCs (Evs/miR-93-5p inhibitor) were isolated, and co-cultured with HK2 cells to explore the effects of EPC-derived Evs overexpressing miR-93-5p on LPS-induced HK2 cell injury. The interaction between miR-93-5p and lysine (K)-specific demethylase 6B (KDM6B) was identified using dual-luciferase reporter assay, and ChIP was used to validate the relationship between KDM6B and tumor necrosis factor-α (TNF-α). Mice were made septic by cecal ligation and puncture (CLP), and then injected with Ev/miR-93-5p inhibitor to explore its functions in vivo. The results found that miR-93-5p and histone H3 Lys27 trimethylation (H3K27me3) were downregulated while KDM6B was upregulated in LPS-treated HK2 cells. EPC-derived Evs alleviated LPS-induced HK2 cell injury, while Ev/miR-93-5p inhibitor potentiated the cell injury in vitro. miR-93-5p was found to directly target KDM6B. Silencing KDM6B induced H3K27me3, inhibiting the activation of TNF-α, thereby weakening LPS-induced HK2 cell injury. EPC-derived Evs containing miR-93-5p attenuated multiple organ injury, vascular leakage, inflammation, and apoptosis in septic mice. In conclusion, the present study demonstrated that endothelial protection from EPC-derived Evs carrying miR-93-5p in sepsis-induced AKI, which was mediated by regulation KDM6BH/3K27me3/TNF-α axis.

Zoledronic acid regulates the synthesis and secretion of IL-1β through Histone methylation in macrophages

Long-term administration of nitrogen-containing bisphosphonates increases the risk of detrimental side effects, such as bisphosphonate-related osteonecrosis of the jaw (BRONJ). BRONJ development is associated with inflammation, but its pathophysiology remains unknown. Here, we examined whether histone methylation is responsible for zoledronic acid (Zol)-induced inflammatory responses. We found that Kdm6a and Kdm6b markedly increased interleukin 1β expression and Gasdermin D cleavage, which are both activated by Caspase 1, in macrophages. Inhibitors of Kdm6a and Kdm6b robustly abolished Zol-enhanced interleukin 1β synthesis and secretion from macrophages. When Kdm6a and Kdm6b were pharmacologically inhibited in vivo, poor healing of the alveolar socket and inflammatory responses were ameliorated in Zol-treated mice. Taken together, we showed the pathologic role of Kdm6a and Kdm6b in Zol-promoted inflammatory responses and demonstrated that Kdm6a and Kdm6b are potential therapeutic targets for the treatment of BRONJ.

Clinical significance of miRNAs in autoimmunity

MicroRNAs (miRNAs) are evolutionally conserved, single-stranded RNAs that regulate gene expression at the posttranscriptional level by disrupting translation. MiRNAs are key players in variety of biological processes that regulate the differentiation, development and activation of immune cells in both innate and adaptive immunity. The disruption and dysfunction of miRNAs can perturb the immune response, stimulate the release of inflammatory cytokines and initiate the production of autoantibodies, and contribute to the pathogenesis of autoimmune diseases, including systemic lupus erythmatosus (SLE), rheumatoid arthritis (RA), primary biliary cholangitis (PBC), and multiple sclerosis (MS). Accumulating studies demonstrate that miRNAs, which can be collected by noninvasive methods, have the potential to be developed as diagnostic and therapeutic biomarkers, the discovery and validation of which is essential for the improvement of disease diagnosis and clinical monitoring. Recently, with the development of detection tools, such as microarrays and NGS (Next Generation Sequencing), large amounts of miRNAs have been identified and suggest a critical role in the pathogenesis of autoimmune diseases. Several miRNAs associated diagnostic biomarkers have been developed and applied clinically, though the pharmaceutical industry is still facing challenges in commercialization and drug delivery. The development of miRNAs is less advanced for autoimmune diseases compared with cancer. However, drugs that target miRNAs have been introduced as candidates and adopted in clinical trials. This review comprehensively summarizes the differentially expressed miRNAs in several types of autoimmune diseases and discusses the role and the significance of miRNAs in clinical management. The study of miRNAs in autoimmunity promises to provide novel and broad diagnostic and therapeutic strategies for a clinical market that is still in its infancy.

Hydrogen sulfide protects against DSS-induced colitis by inhibiting NLRP3 inflammasome

Hydrogen sulfide (H₂S), as the third gasotransmitter, has been shown to be effective in the prevention of inflammation. In addition, the NLRP3 inflammasome is a key player in the pathogenesis of dextran sulfate sodium (DSS)-induced colitis. Therefore, the aim of our research was to determine whether H₂S exerts an anti-inflammatory effect on DSS-induced colitis by targeting NLRP3 inflammasome. Our data showed that DSS-induced colitis is attenuated by H₂S, lessening the shortening of the colon lengths and colonic pathological damages. The cytokines TNF-α, IL-1β, and IL-6 in colon samples were also significantly downregulated by H₂S. Besides, H₂S markedly suppressed the expression of NLRP3 and cleaved caspase-1 (p20) in colons from DSS-induced colitis mice. More importantly, CSE^-/- mice were more susceptive to DSS-induced colitis when compared to wild-type (WT) mice. Our experimental results also suggested that H₂S dose-dependently inhibits the activation of NLRP3 inflammasome in bone marrow-derived macrophages (BMDMs) by reducing the cleavage of caspase-1 and the secretion of IL-1β. Furthermore, the inhibitory effect of H₂S is due to a reduction in reactive oxygen species (ROS) generation and partly dependent on the disruption of nuclear erythroid 2-related factor-2 (Nrf2) activation. Collectively, our study confirms that H₂S exerts its protective effect on DSS-induced mouse colitis at least partly by inhibiting the activation of NLRP3 inflammasome pathway.

Targeting P16INK4A in uterine serous carcinoma through inhibition of histone demethylation

Uterine serous carcinoma (USC) is a subtype of endometrial cancer. Compared with endometrial endometroid carcinoma, the majority of USC cases are more aggressive. Cyclin-dependent kinase inhibitor 2A (P16INK4A) is a canonical tumor suppressor that blocks cell cycle progression; however, P16INK4A is overexpressed in USC. The aim of the present study was to determine the role of P16INK4A in P16INK4A‑positive endometrial cancer, with the hope of elucidating a novel therapeutic approach for this type of malignancy. A total of 2 endometrial cancer cell lines, ETN‑1 and EFE‑184, were selected for further investigation, due to them being known to express high levels of P16INK4A. Using short hairpin RNA targeting P16INK4A, P16INK4A was downregulated in these cancer cell lines. Cell viability and migration were examined via 2D/3D clonogenic and wound healing assays. Subsequently, GSK‑J4, a histone demethylase inhibitor, was employed to deplete P16INK4A in these cancer cell lines and an ex vivo culture system of a patient‑derived xenograft (PDX) endometrial tumor sample. Following P16INK4A knockdown, the proliferation and migration of ETN‑1 and EFE‑184 cells markedly declined. When exposed to GSK‑J4, the levels of KDM6B and P16INK4A were almost completely abrogated, and the cell viability was significantly reduced in these cell lines and the ex vivo‑cultured PDX tumor explants. The association between the levels of P16INK4A, lysine demethylase 6B (KDM6B) and the methylation status of histone 3 lysine 27 (H3K27) in these cell lines and the human USC tumor sample was also demonstrated. P16INK4A appears to be oncogenic in a number of endometrial cancer cell lines. The level of P16INK4A is associated with the methylation status of H3K27. Increased methylation of H3K27 coexists with downregulation of KDM6B and, subsequently, P16INK4A, which reduces cell proliferation and invasiveness in endometrial cancer. The observations of the present study may enable the development of a novel therapeutic strategy for P16INK4A‑positive endometrial cancer, particularly USC.

Increase of cystathionine-γ-lyase (CSE) during late wound repair: Hydrogen sulfide triggers cytokeratin 10 expression in keratinocytes

The gaseous mediators nitric oxide (NO), carbon monoxide (CO) and lately also hydrogen sulfide (H₂S) have been described to contribute to the interplay of protein type- and lipid mediators in the regulation of wound healing. In particular, the recently reported role of H₂S in skin repair remains largely unresolved. Therefore we assessed the expressional kinetics of potential H₂S-producing enzymes during undisturbed skin repair: the cystathionine-γ-lyase (CSE), the cystathionine-β-synthase (CBS) and the 3-mercaptopyruvate sulfurtransferase (MPST). All three enzymes were not transcriptionally induced upon wounding and remained silent through the acute inflammatory and proliferative phase of skin repair. By contrast, CSE expression started to increase significantly at the later stages of healing, when cellular proliferation ceases within the granulation tissue and neoepidermis. The importance of H₂S production in late healing phases was supported by a strong induction of otherwise not-induced CBS to complement the loss of CSE function in CSE-deficient mice. Immunohistochemistry revealed hair follicle keratinocytes and basal keratinocytes of the neo-epidermis covering the wound area as sources of CSE expression. Subsequent in vitro studies implicated a role of CSE-derived H₂S for keratinocyte differentiation: the H₂S-donor GYY4137 markedly increased the Ca²⁺-triggered expression of the early keratinocyte differentiation markers cytokeratin 10 (CK10) and involucrin (IVN) in cultured human keratinocytes. Here, GYY4137-derived H₂S strongly enhanced CK10 expression by increasing the binding of RNA polymerase II to the CK10 promoter.