Artemisinin analog SM934 alleviates epithelial barrier dysfunction via inhibiting apoptosis and caspase-1-mediated pyroptosis in experimental colitis

PM2.5 exacerbates nasal epithelial barrier dysfunction in allergic rhinitis by inducing NLRP3-mediated pyroptosis via the AhR/CYP1A1/ROS axis

Fine particulate matter (PM2.5), a major air pollutant, plays a critical role in exacerbating respiratory diseases such as allergic rhinitis (AR) by inducing inflammation. While its association with AR is well established, the precise mechanisms by which PM2.5 triggers pyroptosis and compromises nasal epithelial barrier integrity remain unclear. This study investigates the role of PM2.5 in promoting pyroptosis in nasal epithelial cells and its contribution to AR pathogenesis. Clinical analysis revealed significantly elevated levels of NLRP3 inflammasomes and pyroptosis-related proteins in the nasal mucosa of patients with AR compared with the control group. In vitro and in vivo experiments further demonstrated that PM2.5 exposure led to a dose-dependent increase in these markers in nasal epithelial cells and AR mouse models. Functional studies using NLRP3 agonists and inhibitors confirmed that PM2.5 induces NLRP3-mediated pyroptosis, resulting in tight junction protein degradation and compromised epithelial barrier integrity. Mechanistic investigations showed that PM2.5 activates the aryl hydrocarbon receptor (AhR) pathway, driving the transcription of cytochrome P450 1A1 (CYP1A1) and increasing reactive oxygen species (ROS) production. Notably, AhR downregulation alleviated PM2.5-induced pyroptosis and epithelial barrier dysfunction, whereas CYP1A1 overexpression reversed these protective effects, highlighting the pivotal role of the AhR/CYP1A1/ROS axis in mediating PM2.5-induced epithelial damage. In conclusion, this study uncovers a novel mechanism by which PM2.5 promotes NLRP3-mediated pyroptosis through the AhR/CYP1A1/ROS signaling pathway, ultimately leading to epithelial barrier disruption and AR exacerbation. These findings highlight the urgent need for strategies to minimize PM2.5 exposure and mitigate its detrimental effects on respiratory health.

Dihydroartemisinin attenuates acetic acid-induced ulcerative colitis in rats: Suppression of inflammation and modulation of NFκβ/TNF-α/RIPK1-mediated necroptosis and apoptosis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by the overproduction of reactive oxygen species (ROS) and the release of inflammatory mediators. Dihydroartemisinin (DHA) is a semi-synthetic active metabolite of artemisinin that has anti-inflammatory, antioxidant, and anti-fibrotic properties.

OBJECTIVE

This study aimed to assess the therapeutic benefits of DHA on acetic acid(AA) -induced UC in rats, with particular emphasis on its anti-inflammatory effects and its influence on NFκB/TNF-α/RIPK1 necroptotic pathways.

METHODS

Eighteen rats were allocated into control, acetic acid-induced colitis (AA), and DHA-treated (AA+DHA) groups. Colitis was caused by rectal instillation of 5 % acetic acid. DHA was supplied via intraperitoneal injection. Histological, biochemical studies of oxidative stress, inflammatory and anti-inflammatory mediators, Western blotting for TNF-α, RIPK1, and caspase 3, and immunohistochemical assessment of NFκB, TNF-α, and RIPK1, were conducted.

RESULTS

DHA treatment markedly diminished macroscopic damage, disease activity index, histopathology scores, and malondialdehyde (MDA) levels, enhancing glutathione (GSH) levels. Additionally, DHA decreased serum TNF-α and IL-6 and increased IL-10. Western blotting and immunohistochemistry investigations validated the reduced expression of TNF-α, RIPK1, and caspase 3 in DHA-treated rats.

CONCLUSION

DHA demonstrates protective properties against acetic acid-induced UC by decreasing oxidative stress and inflammation, modifying TNF-α activity to regulate apoptotic and necroptotic pathways. So, DHA may be a favorable therapeutic alternative for the management of ulcerative colitis.

Qilian Jiechang Ning Alleviates TNBS-Induced Ulcerative Colitis in Mice and Segatella copri Outer Membrane Vesicle-Triggered Inflammation in Colon Epithelial Cells via the Caspase-1/11-GSDMD Pathways

INTRODUCTION

Qilian Jiechang Ning (QJN), a traditional Chinese herbal formula, has demonstrated potential therapeutic effects in the treatment of ulcerative colitis (UC). This study aims to investigate the mechanism of QJN in the outer membrane vesicles (OMVs) of Segatella copri (S. copri)-induced colon epithelial cells and UC mice.

METHODS

Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were utilized to assess the morphology and size of OMVs. Inflammation markers and tight junction protein levels in HCoEpiCs induced by OMVs were monitored using ELISA and western blot. QJN was administered to intervene in HCoEpiCs treated with S. copri OMVs. Additionally, trinitrobenzene sulfonic acid (TNBS)-induced mouse models were conducted to evaluate the therapeutic effects of QJN on UC.

RESULTS

S. copri OMVs treated with QJN demonstrated a significant reduction in particle size, protein concentration, and LPS content. In HCoEpiCs, QJN effectively decreased the expression of inflammation-inducing cytokines (IL-1β, IL-18, IL-6, TNF-α) and proinflammatory proteins (GSDMD-N, NLRP3, ASC, cleaved Caspase-1, cleaved Caspase-4) triggered by S. copri OMVs, while enhancing the expression of tight junction proteins (ZO-1 and Occludin). In the UC mouse models, QJN significantly reduced the Disease Activity Index (DAI), improved colon length, lowered LPS levels, ameliorated colonic tissue damage, and inhibited Caspase-1- and Caspase-11-dependent inflammatory responses.

CONCLUSION

QJN can alleviate S. copri-OMV-induced inflammatory response in colonic epithelial cells and reduce symptoms of UC in mouse models by modulating the Caspase-1 and Caspase-11 pathways.

Bakuchiol mitigates colitis through GPR120 activation

BACKGROUND

Sishen Wan (SSW) is a traditional herbal formula widely used in China to treat inflammatory bowel disease (IBD). However, effective compound(s) and the mechanism(s) of action remain mostly unelucidated.

PURPOSE

A demonstration study was carried out to identify the main components of SSW, investigate its effects, and explore the target mechanism in the treatment of IBD.

STUDY DESIGN AND METHODS

The main chemical species of the SSW were identified using ultra-high-performance liquid chromatography coupled with mass spectrometry (UHPLC-MS/MS) method. The therapeutic effects of bakuchiol, the main component, were further analyzed in DSS-induced colitis mice. The target of bakuchiol was predicted using virtual screening and validated using pharmacological approaches. The possible mechanisms of bakuchiol were investigated using RNA-seq and bioassays with cytokines-induced human epithelial cell lines.

RESULTS

Bakuchiol was identified as the main component of the SSW. Bakuchiol displayed therapeutic potential similar to SSW in alleviating body weight loss, disease activity index (DAI) increases, colonic shortening, colonic pathological injury and inhibiting proinflammatory genes Tnf-α, Il6, Il17a and Ifn-γ expression in mice with DSS-induced colitis. Compared with the clinical drug mesalazine, bakuchiol at lower doses showed a superior effect in alleviating body weight loss, DAI increases and colonic shortening. RNA-seq revealed that bakuchiol treatment suppresses inflammation pathways, such as chemokine signaling, IL-17 signaling and TNF signaling. Pharmacological profiling at a panel of GPCRs associated with IBD showed that bakuchiol was a GPR120 agonist with an EC50 value of 37.80 ± 3.10 μM. In the TNF-α-induced HT-29 cells, we found that bakuchiol maintained the barrier function partially via the activation of GPR120.

CONCLUSION

This work demonstrates that bakuchiol is instrumental in SSW and provides evidence of the therapeutic effect of bakuchiol via activation of the GPR120 receptor, suggesting that bakuchiol may represent a novel potential agent for preventing and treating IBD.

Artemisinin regulates cell proliferation, apoptosis, and the inflammatory response of human dental pulp stem cells through the p53 signaling pathway under LPS-induced inflammation

OBJECTIVE

The purpose of this study was to investigate the effects and mechanism of artemisinin (ART) on the proliferation, apoptosis, and inflammatory response of human dental pulp stem cells (HDPSCs) under lipopolysaccharide (LPS)-induced inflammation.

METHODS

HDPSCs were isolated, cultured, and identified by flow cytometry and three-directional differentiation induction. A suitable concentration of LPS was selected to mimic the inflammatory condition in vitro. After culturing with ART and LPS for 48 h, cell proliferation was observed by CCK-8 assay; cell apoptosis was observed by flow cytometry, western blot, and Caspase-3 activity; and the inflammatory response was observed by qRT-PCR and ELISA. Transcriptome sequencing, immunofluorescence staining, qRT-PCR, western blot, and RITA were used to explore the underlying mechanism.

RESULTS

HDPSCs were successfully isolated and exhibited the potential for multilineage differentiation. 0.1 μg/mL of LPS was utilized to mimic the inflammatory condition. ART promoted HDPSCs proliferation but repressed apoptosis and the inflammatory response under LPS-induced inflammation. Further, ART exerted its effect through the p53 signaling pathway.

CONCLUSION

ART inhibited the p53 signaling pathway to promote HDPSCs proliferation, but hinder apoptosis and the inflammatory response under LPS-induced inflammation.

CLINICAL SIGNIFICANCE

This study demonstrates that ART facilitates the alleviation of inflammation and preserves the viability of HDPSCs. Therefore, ART may serve as a promising therapeutic drug for the repair and regeneration of dental pulp in the treatment of deep caries and reversible pulpitis.

Regulation of pyroptosis by natural products in ulcerative colitis: mechanisms and therapeutic potential

Ulcerative colitis (UC), a chronic inflammatory bowel disease, is driven by dysregulated immune responses and persistent intestinal inflammation. Pyroptosis, a caspase/gasdermin-mediated inflammatory cell death that exacerbates mucosal damage through excessive cytokine release and epithelial barrier disruption. Although pyroptosis is considered to be a key mechanism in the pathogenesis of UC, the systematic assessment of the role of natural products in targeting the pyroptosis pathway remains a critical research gap. The purpose of this review is to investigate the regulatory effects of natural products on pyroptosis in UC and elucidate the mechanisms of action and potential therapeutic effects. Key findings highlight polyphenols (e.g., resveratrol), flavonoids (e.g., Quercetin), and terpenoids as promising agents that inhibit NLRP3 inflammasome activation, suppress gasdermin D cleavage, and restore barrier integrity, thereby reducing pro-inflammatory cytokine release in preclinical UC models. Current evidence shows enhanced efficacy and safety when these compounds are combined with standard therapies, but clinical translation requires overcoming three key barriers: limited human trial data, uncharacterized polypharmacology, and suboptimal pharmacokinetics needing formulation refinement. Future research should prioritize standardized animal-to-human translational models, mechanistic studies on synergistic pathways, and rigorous clinical validation to harness the full potential of natural products in pyroptosis-targeted UC therapies.

Role of Chinese Medicine Monomers in Dry Eye Disease: Breaking the Vicious Cycle of Inflammation

Dry eye disease (DED) is a chronically inflammatory ocular surface disorder of unknown pathogenesis. Anti-inflammatory medications, artificial tears, autologous serum, and LipiFlow have been shown to be highly beneficial in alleviating symptoms. Nevertheless, these interventions often provide only short-term results and do not address the underlying problems of the disease. There is growing evidence that the risk of DED is associated with a vicious cycle of inflammation. This vicious cycle of inflammation is produced by the interaction of several factors, including tear film hyperosmolarity, tear film instability, inflammation, and apoptosis. Chinese medicine monomers, distinguished by their multicomponent and multitarget advantages, have been shown to help treat DED by modulating tear film status, and inhibiting inflammatory responses, and apoptosis, providing a new way of thinking of the management of DED in Chinese medicine.

Targeting programmed cell death in inflammatory bowel disease through natural products: New insights from molecular mechanisms to targeted therapies

Inflammatory bowel disease (IBD) is an autoimmune disorder primarily characterized by intestinal inflammation and recurrent ulceration, leading to a compromised intestinal barrier and inflammatory infiltration. This disorder's pathogenesis is mainly attributed to extensive damage or death of intestinal epithelial cells, along with abnormal activation or impaired death regulation of immune cells and the release of various inflammatory factors, which contribute to the inflammatory environment in the intestines. Thus, maintaining intestinal homeostasis hinges on balancing the survival and functionality of various cell types. Programmed cell death (PCD) pathways, including apoptosis, pyroptosis, autophagy, ferroptosis, necroptosis, and neutrophil extracellular traps, are integral in the pathogenesis of IBD by mediating the death of intestinal epithelial and immune cells. Natural products derived from plants, fruits, and vegetables have shown potential in regulating PCD, offering preventive and therapeutic avenues for IBD. This article reviews the role of natural products in IBD treatment by focusing on targeting PCD pathways, opening new avenues for clinical IBD management.

Cerium Oxide-Loaded Exosomes Derived From Regulatory T Cells Ameliorate Inflammatory Bowel Disease by Scavenging Reactive Oxygen Species and Modulating the Inflammatory Response

Background

Abnormal immune homeostasis, which leads to the accumulation of reactive oxygen species (ROS) and an inflammatory response, plays a crucial role in accelerating the progression of inflammatory bowel disease (IBD). The lack of targeted therapeutic strategies significantly hampers the efficacy of clinical treatments for IBD. This study presents cerium oxide nanoparticle-loaded regulatory T cell-derived exosomes (exo@nCeO) as innovative anti-inflammatory and antioxidant agents specifically designed to address the effects of immune dysregulation.

Methods

In this work, the morphology and antioxidant properties of nano-cerium oxide were characterized using transmission electron microscopy, as well as hydroxyl radical and 1,1-diphenyl-2-picrylhydrazyl radical assays. Tumor necrosis factor-α and dextran sulfate sodium were employed to establish cellular and animal models of IBD. The impact of exo@nCeO on ROS scavenging and anti-inflammatory activity in intestinal epithelial cells was assessed using dihydroethidium and 2,7-dichlorodihydrofluorescein staining, Western blotting, and apoptosis flow cytometry analysis. Hematoxylin and eosin staining, along with immunohistochemistry and immunofluorescence staining, were utilized to evaluate intestinal epithelial inflammation and ROS levels in the IBD mouse model.

Results

The findings demonstrate that exo@nCeO possesses augmented anti-inflammatory properties and ROS scavenging abilities in intestinal epithelial cells. In murine models of IBD, exo@nCeO effectively maintained the integrity of the intestinal epithelial barrier and impeded the progression of IBD.

Conclusion

This study introduces a novel therapeutic approach for IBD and underscores a potential strategy for addressing diseases associated with inflammation and oxidative stress.

[Nodakenin ameliorates TNBS-induced experimental colitis in mice by inhibiting pyroptosis of intestinal epithelial cells]

OBJECTIVES

To investigate the therapeutic mechanism of nodakenin for Crohn's disease (CD)-like colitis in mice.

METHODS

Using a colonic organoid model with lipopolysaccharide (LPS)- and ATP-induced pyroptosis, we investigated the effects of nodakenin on pyroptosis, intestinal barrier function and inflammatory response by detecting key pyroptosis-regulating factors and assessing changes in permeability and pro-inflammatory factors. In a mouse model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced CD-like colitis, the therapeutic effect of nodakenin was evaluated by measuring changes in body weight, DAI score, colonic histopathologies, inflammation score, intestinal barrier function and intestinal epithelial cell pyroptosis. The mechanism of nodakenin protection against pyroptosis of intestinal epithelial cells was explored using network pharmacology analysis and in vivo and in vitro experiments.

RESULTS

In LPS- and ATP-induced colonic organoids, treatment with nodakenin significantly inhibited the expressions of NLRP3, GSDMD-N, cleaved caspase-1 and caspase-11, improved intestinal FITC-dextran (FD4, 4000) permeability, and decreased the levels of IL-1β and IL-18. In the mouse model of TNBS-induced colitis, nodakenin treatment significantly alleviated weight loss, reduced DAI score, inflammatory cell infiltration and inflammation score, and decreased serum FD4 and I-FABP levels and bacteria translocation to the mesenteric lymph nodes, spleen and liver. The mice with nodakenin treatment had also lowered expressions of NLRP3, GSDMD-N, cleaved caspase-1 and caspase-11 in the intestinal mucosa. Network pharmacology analysis suggested that the inhibitory effect of nodakenin on colitis was associated with the PI3K/Akt pathway. In both the colonic organoid model and mouse models of colitis, nodakenin effectively inhibited the activation of the PI3K/Akt pathway, and the application of IGF-1, a PI3K/Akt pathway activator, strongly attenuated the protective effect of nodakenin against intestinal epithelial cell pyroptosis and intestinal barrier dysfunction.

CONCLUSIONS

Nodakenin protects intestinal barrier function and alleviates CD-like colitis in mice at least partly by inhibiting PI3K/Akt signaling to reduce intestinal epithelial cell pyroptosis.

Elevated levels of IRF1 and CASP1 as pyroptosis-related biomarkers for intestinal epithelial cells in Crohn's disease

Introduction

Crohn's disease (CD) is a complex inflammatory condition with the potential for severe complications. Pyroptosis is an inflammatory form of programmed cell death, and the role of pyroptosis in intestinal epithelial cells of CD remains unclear.

Methods

In this study, pyroptosis-related hub genes were identified using datasets from the Gene Expression Omnibus database through differential expression analysis, machine learning algorithms, and single-cell sequencing analysis. Hub gene expression was validated using clinical samples and a trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model.

Results

Six pyroptosis-related hub genes (CASP1, IRF1, ZBP1, MLKL, MMP1, HTRA1) were identified. IRF1 and CASP1 exhibited significant upregulation in CD, including both colonic and ileal subtypes, with good diagnostic value across different CD subtypes. Additionally, these two genes were not elevated in any other intestinal disorders, except for ulcerative colitis. Single-cell sequencing analysis revealed a significant interaction between intestinal epithelial cells (IECs) and monocytes. The clinical samples further confirmed that the mRNA levels of IRF1 and CASP1 were significantly higher in CD patients compared to healthy controls. Additionally, the colitis rat model validated the upregulation of Irf1 and Casp1 at both mRNA and protein levels.

Conclusion

Our findings identified IRF1 and CASP1 as critical pyroptosis-related biomarkers for IECs in CD, contributing to the understanding of pyroptosis in CD pathogenesis.

Butyrate attenuates intestinal inflammation in Crohn's disease by suppressing pyroptosis of intestinal epithelial cells via the cGSA-STING-NLRP3 axis

Butyrate can strengthen the intestinal epithelial barrier. However, the mechanisms by which butyrate affects intestinal epithelial cells (IECs) pyroptosis in Crohn's disease (CD) remain unclear. In this study, we collected colonic biopsy samples from CD patients and healthy controls to assess pyroptosis levels. Our findings indicated elevated expression of pyroptosis markers in CD patients, alongside distinct morphological evidence of pyroptosis in IECs. We further investigated the effects of tributyrin on pyroptosis and the cGAS-STING pathway in a trinitrobenzene sulfonic acid-induced colitis rat model. Tributyrin significantly mitigated intestinal inflammation, reduced pathological progression, and inhibited pyroptosis and cGAS-STING pathway activation in the colitis rat model. Similarly, in an in vitro model of IECs pyroptosis, sodium butyrate inhibited pyroptosis and cGAS-STING pathway activation in HT-29 cells. Co-treatment with a cGAS-STING pathway activator and butyrate demonstrated that the activator reversed the inhibitory effects of butyrate on pyroptosis and cGAS-STING pathway activation in both the colitis rat model and HT-29 cells. Mechanistically, the cGAS-STING pathway was found to interact with NLRP3. Taken together, butyrate may mitigate intestinal inflammation in CD by suppressing cGAS-STING-NLRP3 axis-mediated IECs pyroptosis. These findings offer new insights into potential therapeutic strategies for managing CD.

PI(4,5)P2 alleviates colitis by inhibiting intestinal epithelial cell pyroptosis through NNMT-mediated RBP4 m6A modification

Lipid metabolism disorder is a critical feature of Crohn's disease (CD). Phosphatidylinositol (PI) and its derivative, phosphatidylinositol bisphosphate (PIP2), are associated with CD. The mechanisms underlying such association remain unknown. In this study, we explored the role played by the major PI derivative, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], in CD pathogenesis. The relationship between CD activity and PI or PIP2 was analyzed via lipidomics. The mucosal expression of PI(4,5)P2 in patients with CD was measured using immunofluorescence. The function and mechanism of PI(4,5)P2 were examined in dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-induced Caco-2 cell models, along with MeRIP and mRNA sequencing. The results suggested lipid PI and PIP2 were substantially negatively associated with disease activity and high-sensitivity C-reactive protein. PI(4,5)P2 was substantially downregulated in the inflamed mucosa of patients with CD. PI(4,5)P2 alleviated mouse colitis, with improvements in survival rate, colon length, weight, and disease activity index. PI(4,5)P2 also alleviated DSS-induced tissue damage, tight junction loss, and intestinal epithelial cell (IEC) pyroptosis. In the in vitro LPS-induced cell model, PI(4,5)P2 inhibited pyroptosis, as well as NLRP3, and caspase-1 expression, in addition to reducing interleukin (IL)-18, IL-1β, and lactate dehydrogenase (LDH) secretion. PI(4,5)P2 mediated NNMT upregulation in mice and Caco-2 cells and suppressed pyroptosis in IECs. NNMT knockdown restricted the inhibitory effect of PI(4,5)P2 on IEC pyroptosis. NNMT inhibited the stability of RBP4 mRNA via m6A modification, thereby preventing pyroptosis following PI(4,5)P2 treatment. Significant correlations were also observed between PI(4,5)P2 and NNMT, NNMT and RBP4, and RBP4 and GSDMD expression in the intestinal tissues from patients with CD. Our results indicated that PI(4,5)P2 ameliorates colitis by inhibiting IEC pyroptosis via NNMT-mediated RBP4 m6A modification. Thus, PI(4,5)P2 shows potential as a therapeutic target in CD.

The mesenteric adipokine SFRP5 alleviated intestinal epithelial apoptosis improving barrier dysfunction in Crohn's disease

The hypertrophic mesenteric adipose tissue (htMAT) of Crohn disease (CD) participates in inflammation through the expression of adipokines, but the exact mechanism of this action in the intestine is unknown. Here, we analyzed the expression of secreted frizzled-related protein 5 (SFRP5), an adipokine with cytoprotective effects, in htMAT and its role in CD. The results of this study revealed that the level of SFPR5 increased in the diseased MAT (htMAT) of CD patients and aggregated among intestinal epithelial cells in the diseased intestine and that it could ameliorate intestinal barrier dysfunction in tumor necrosis factor alpha (TNF-α)-stimulated colonic organoids and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced mice at least in part through the inhibition of Wnt5a-mediated apoptosis in epithelial cells. This study elucidates possible mechanisms by which mesenteric adipokines influence the progression of enteritis and provides a new theoretical basis for the treatment of CD via the mesenteric pathway.

Quercetin restores respiratory mucosal barrier dysfunction in Mycoplasma gallisepticum-infected chicks by enhancing Th2 immune response

BACKGROUND

Mycoplasma gallisepticum (MG) has long been a pathogenic microorganism threatening the global poultry industry. Previous studies have demonstrated that the mechanism by which quercetin (QUE) inhibits the colonization of MG in chicks differs from that of antibiotics. However, the molecular mechanism by which QUE facilitates the clearance of MG remains unclear.

PURPOSE

The aim of this study was to investigate the molecular mechanism of MG clearance by QUE, with the expectation of providing new options for the treatment of MG.

METHODS

A model of MG infection in chicks and MG-induced M1 polarization in HD-11 cells were established. The mechanism of QUE clearance of MG was investigated by evaluating the relationship between tracheal mucosal barrier integrity, antibody levels, Th1/Th2 immune balance and macrophage metabolism and M1/M2 polarization balance. Furthermore, network pharmacology and molecular docking techniques were employed to explore the potential molecular pathways connecting QUE, M2 polarization, and fatty acid oxidation (FAO).

RESULTS

The findings indicate that QUE remodels tracheal mucosal barrier function by regulating tight junctions and secretory immunoglobulin A (sIgA) expression levels. This process entails the regulatory function of QUE on the Th1/Th2 immune imbalance that is induced by MG infection in the tracheal mucosa. Moreover, QUE intervention impeded the M1 polarization of HD-11 cells induced by MG infection, while simultaneously promoting M2 polarization through the induction of FAO. Conversely, inhibitors of the FAO pathway impede this effect. The results of computer network analysis suggest that QUE may induce FAO via the PI3K/AKT pathway to promote M2 polarization. Notably, inhibition of the PI3K/AKT pathway was found to effectively inhibit M2 polarization in HD-11 cells, while having a limited effect on FAO.

CONCLUSIONS

QUE promotes M2 polarization of HD-11 cells to enhance Th2 immune response through FAO and PI3K/AKT pathways, thereby restoring tracheal mucosal barrier function and ultimately inhibiting MG colonization.

Glaesserella parasuis serotype 5 induces pyroptosis via the RIG-I/MAVS/NLRP3 pathway in swine tracheal epithelial cells

Glaesserella parasuis (G. parasuis) is a common Gram-negative commensal bacterium in the upper respiratory tract of swine that can cause Glässer's disease under stress conditions. Pyroptosis is an important immune defence mechanism of the body that plays a crucial role in clearing pathogen infections and endogenous danger signals. This study aimed to investigate the mechanism of G. parasuis serotype 5 SQ (GPS5-SQ)-induced pyroptosis in swine tracheal epithelial cells (STECs). The results of the present study demonstrated that GPS5-SQ infection induces pyroptosis in STECs by enhancing the protein level of the N-terminal domain of gasdermin D (GSDMD-N) and activating the NOD-like receptor protein 3 (NLRP3) inflammasome. Furthermore, the levels of pyroptosis-related proteins, including GSDMD-N and cleaved caspase-1 were considerably decreased in STECs after the knockdown of retinoic acid inducible gene-I (RIG-I) and mitochondrial antiviral signaling protein (MAVS). These results indicated that GPS5-SQ might trigger pyroptosis through the activation of the RIG-I/MAVS/NLRP3 signaling pathway. More importantly, the reactive oxygen species (ROS) scavenger N-acetylcysteine (NAC) repressed the activation of the RIG-I/MAVS/NLRP3 signaling and rescued the decrease in Occludin and zonula occludens-1 (ZO-1) after GPS5-SQ infection. Overall, our findings show that GPS5-SQ can activate RIG-I/MAVS/NLRP3 signaling and destroy the integrity of the epithelial barrier by inducing ROS generation in STECs, shedding new light on G. parasuis pathogenesis.

Artemisinins: Promising drug candidates for the treatment of autoimmune diseases

Autoimmune diseases are characterized by the immune system's attack on one's own tissues which are highly diverse and diseases differ in severity, causing damage in virtually all human systems including connective tissue (e.g., rheumatoid arthritis), neurological system (e.g., multiple sclerosis) and digestive system (e.g., inflammatory bowel disease). Historically, treatments normally include pain-killing medication, anti-inflammatory drugs, corticosteroids, and immunosuppressant drugs. However, given the above characteristics, treatment of autoimmune diseases has always been a challenge. Artemisinin is a natural sesquiterpene lactone initially extracted and separated from Chinese medicine Artemisia annua L., which has a long history of curing malaria. Artemisinin's derivatives such as artesunate, dihydroartemisinin, artemether, artemisitene, and so forth, are a family of artemisinins with antimalarial activity. Over the past decades, accumulating evidence have indicated the promising therapeutic potential of artemisinins in autoimmune diseases. Herein, we systematically summarized the research regarding the immunoregulatory properties of artemisinins including artemisinin and its derivatives, discussing their potential therapeutic viability toward major autoimmune diseases and the underlying mechanisms. This review will provide new directions for basic research and clinical translational medicine of artemisinins.

Inhibition of Sema4D attenuates pressure overload-induced pathological myocardial hypertrophy via the MAPK/NF-κB/NLRP3 pathways

Sema4D (CD100) is closely related to pathological and physiological processes, including tumor growth, angiogenesis and cardiac development. Nevertheless, the role and mechanism of Sema4D in cardiac hypertrophy are still unclear to date. To assess the impact of Sema4D on pathological cardiac hypertrophy, TAC surgery was performed on C57BL/6 mice which were transfected with AAV9-mSema4D-shRNA or AAV9-mSema4D adeno-associated virus by tail vein injection. Our results indicated that Sema4D knockdown mitigated cardiac hypertrophy, fibrosis and dysfunction when exposed to pressure overload, and Sema4D downregulation markedly inhibited cardiomyocyte hypertrophy induced by angiotensin II. Meanwhile, Sema4D overexpression had the opposite effect in vitro and in vivo. Furthermore, analysis of signaling pathways showed that Sema4D activated the MAPK pathway during cardiac hypertrophy induced by pressure overload, and the pharmacological mitogen-activated protein kinase kinase 1/2 inhibitor U0126 almost completely reversed Sema4D overexpression-induced deteriorated phenotype, resulting in improved cardiac function. Further research indicated that myocardial hypertrophy induced by Sema4D was closely related to the expression of the pyroptosis-related proteins PP65, NLRP3, caspase-1, ASC, GSDMD, IL-18 and IL-1β. In conclusion, our study demonstrated that Sema4D regulated the process of pathological myocardial hypertrophy through modulating MAPK/NF-κB/NLRP3 pathway, and Sema4D may be the promising interventional target of cardiac hypertrophy and heart failure.

A Novel Polysaccharide Separated from Panax Notoginseng Residue Ameliorates Restraint Stress- and Lipopolysaccharide-induced Enteritis in Mice

Polysaccharides are rich in Panax notoginseng residue after extraction. This study aims to explore the structural characteristics of PNP-20, which is a homogeneous polysaccharide, separated from P. notoginseng residue by fractional precipitation and evaluate the anti-enteritis effect of PNP-20. The structure of PNP-20 was determined by spectroscopic analyses. A mouse model with enteritis induced by restraint stress (RS) and lipopolysaccharide (LPS) was used to evaluate the pharmacological effect of PNP-20. The results indicated that PNP-20 consisted of glucose (Glc), galactose (Gal), Mannose (Man) and Rhamnose (Rha). PNP-20 was composed of Glcp-(1→, →4)-α-Glcp-(1→, →4)-α-Galp-(1→, →4,6)-α-Glcp-(1→, →4)-Manp-(1→ and →3)-Rhap-(1→, and contained two backbone fragments of →4)-α-Glcp-(1→4)- α-Glcp-(1→ and →4)-α-Galp-(1→4)-α-Glcp-(1→. PNP-20 reduced intestinal injury and inflammatory cell infiltration in RS- and LPS-induced enteritis in mice. PNP-20 decreased the expression of intestinal tumor necrosis factor-α, NOD-like receptor family pyrin domain containing 3, and nuclear factor-κB and increased the expression of intestinal superoxide dismutase 2. In conclusion, PNP-20 may be a promising material basis of P. Notoginseng for the treatment of inflammatory bowel disease.

NOD-like receptors mediate homeostatic intestinal epithelial barrier function: promising therapeutic targets for inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease that involves host genetics, the microbiome, and inflammatory responses. The current consensus is that the disruption of the intestinal mucosal barrier is the core pathogenesis of IBD, including intestinal microbial factors, abnormal immune responses, and impaired intestinal mucosal barrier. Cumulative data show that nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are dominant mediators in maintaining the homeostasis of the intestinal mucosal barrier, which play critical roles in sensing the commensal microbiota, maintaining homeostasis, and regulating intestinal inflammation. Blocking NLRs inflammasome activation by botanicals may be a promising way to prevent IBD progression. In this review, we systematically introduce the multiple roles of NLRs in regulating intestinal mucosal barrier homeostasis and focus on summarizing the activities and potential mechanisms of natural products against IBD. Aiming to propose new directions on the pathogenesis and precise treatment of IBD.

Inhibition of GSDMD-mediated pyroptosis triggered by Trichinella spiralis intervention contributes to the alleviation of DSS-induced ulcerative colitis in mice

BACKGROUND

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing worldwide. Although there is currently no completely curative treatment, helminthic therapy shows certain therapeutic potential for UC. Many studies have found that Trichinella spiralis (T.s) has a protective effect on UC, but the specific mechanism is still unclear.

METHODS

Balb/c mice drank dextran sulfate sodium (DSS) to induce acute colitis and then were treated with T.s. In vitro experiments, the LPS combination with ATP was used to induce the pyroptosis model, followed by intervention with crude protein from T.s (T.s cp). Additionally, the pyroptosis agonist of NSC or the pyroptosis inhibitor vx-765 was added to intervene to explore the role of pyroptosis in DSS-induced acute colitis. The degree of pyroptosis was evaluated by western blot, qPCR and IHC, etc., in vivo and in vitro.

RESULTS

T.s intervention significantly inhibited NLRP3 inflammasome activation and GSDMD-mediated pyroptosis by downregulating the expression of pyroptosis-related signatures in vitro (cellular inflammatory model) and in vivo (DSS-induced UC mice model). Furthermore, blockade of GSDMD-mediated pyroptosis by the caspase-1 inhibitor vx-765 has a similar therapeutic effect on DSS-induced UC mice with T.s intervention, thus indicating that T.s intervention alleviated DSS-induced UC in mice by inhibiting GSDMD-mediated pyroptosis.

CONCLUSION

This study showed that T.s could alleviate the pathological severity UC via GSDMD-mediated pyroptosis, and it provides new insight into the mechanistic study and application of helminths in treating colitis.

TGR5 agonist inhibits intestinal epithelial cell apoptosis via cAMP/PKA/c-FLIP/JNK signaling pathway and ameliorates dextran sulfate sodium-induced ulcerative colitis

Excessive apoptosis of intestinal epithelial cell (IEC) is a crucial cause of disrupted epithelium homeostasis, leading to the pathogenesis of ulcerative colitis (UC). The regulation of Takeda G protein-coupled receptor-5 (TGR5) in IEC apoptosis and the underlying molecular mechanisms remained unclear, and the direct evidence from selective TGR5 agonists for the treatment of UC is also lacking. Here, we synthesized a potent and selective TGR5 agonist OM8 with high distribution in intestinal tract and investigated its effect on IEC apoptosis and UC treatment. We showed that OM8 potently activated hTGR5 and mTGR5 with EC50 values of 202 ± 55 nM and 74 ± 17 nM, respectively. After oral administration, a large amount of OM8 was maintained in intestinal tract with very low absorption into the blood. In DSS-induced colitis mice, oral administration of OM8 alleviated colitis symptoms, pathological changes and impaired tight junction proteins expression. In addition to enhancing intestinal stem cell (ISC) proliferation and differentiation, OM8 administration significantly reduced the rate of apoptotic cells in colonic epithelium in colitis mice. The direct inhibition by OM8 on IEC apoptosis was further demonstrated in HT-29 and Caco-2 cells in vitro. In HT-29 cells, we demonstrated that silencing TGR5, inhibition of adenylate cyclase or protein kinase A (PKA) all blocked the suppression of JNK phosphorylation induced by OM8, thus abolished its antagonizing effect against TNF-α induced apoptosis, suggesting that the inhibition by OM8 on IEC apoptosis was mediated via activation of TGR5 and cAMP/PKA signaling pathway. Further studies showed that OM8 upregulated cellular FLICE-inhibitory protein (c-FLIP) expression in a TGR5-dependent manner in HT-29 cells. Knockdown of c-FLIP blocked the inhibition by OM8 on TNF-α induced JNK phosphorylation and apoptosis, suggesting that c-FLIP was indispensable for the suppression of OM8 on IEC apoptosis induced by OM8. In conclusion, our study demonstrated a new mechanism of TGR5 agonist on inhibiting IEC apoptosis via cAMP/PKA/c-FLIP/JNK signaling pathway in vitro, and highlighted the value of TGR5 agonist as a novel therapeutic strategy for the treatment of UC.

Medicinal Plants, Phytochemicals and Regulation of the NLRP3 Inflammasome in Inflammatory Bowel Diseases: A Comprehensive Review

Ongoing research explores the underlying causes of ulcerative colitis and Crohn's disease. Many experts suggest that dysbiosis in the gut microbiota and genetic, immunological, and environmental factors play significant roles. The term "microbiota" pertains to the collective community of microorganisms, including bacteria, viruses, and fungi, that reside within the gastrointestinal tract, with a particular emphasis on the colon. When there is an imbalance or disruption in the composition of the gut microbiota, it is referred to as dysbiosis. Dysbiosis can trigger inflammation in the intestinal cells and disrupt the innate immune system, leading to oxidative stress, redox signaling, electrophilic stress, and inflammation. The Nod-like Receptor (NLR) Family Pyrin Domain Containing 3 (NLRP3) inflammasome, a key regulator found in immunological and epithelial cells, is crucial in inducing inflammatory diseases, promoting immune responses to the gut microbiota, and regulating the integrity of the intestinal epithelium. Its downstream effectors include caspase-1 and interleukin (IL)-1β. The present study investigated the therapeutic potential of 13 medicinal plants, such as Litsea cubeba, Artemisia anomala, Piper nigrum, Morus macroura, and Agrimonia pilosa, and 29 phytocompounds such as artemisitene, morroniside, protopine, ferulic acid, quercetin, picroside II, and hydroxytyrosol on in vitro and in vivo models of inflammatory bowel diseases (IBD), with a focus on their effects on the NLRP3 inflammasome. The observed effects of these treatments included reductions in IL-1β, tumor necrosis factor-alpha, IL-6, interferon-gamma, and caspase levels, and increased expression of antioxidant enzymes, IL-4, and IL-10, as well as regulation of gut microbiota. These effects could potentially provide substantial advantages in treating IBD with few or no adverse effects as caused by synthetic anti-inflammatory and immunomodulated drugs. However, additional research is necessary to validate these findings clinically and to develop effective treatments that can benefit individuals who suffer from these diseases.