Ring1a protects against colitis through regulating mucosal immune system and colonic microbial ecology

RING1 dictates GSDMD-mediated inflammatory response and host susceptibility to pathogen infection

RING1 is an E3 ligase component of the polycomb repressive complex 1 (PRC1) with known roles in chromatin regulation and cellular processes such as apoptosis and autophagy. However, its involvement in inflammation and pyroptosis remains elusive. Here, we demonstrate that human RING1, not RING2, promotes K48-linked ubiquitination of Gasdermin D (GSDMD) and acts as a negative regulator of pyroptosis and bacterial infection. Indeed, we showed that loss of Ring1 increased S. typhimurium infectious load and mortality in vivo. Though RING1 deletion initially reduced M. tuberculosis (Mtb) infectious load in vivo, increased lung inflammation and impaired immune defense responses were later observed. Moreover, Ring1 knockout exacerbated acute sepsis induced by lipopolysaccharide (LPS) in vivo. Mechanistically, RING1 directly interacts with GSDMD and ubiquitinates the K51 and K168 sites of GSDMD for K48-linked proteasomal degradation, thereby inhibiting pyroptosis. Inhibition of RING1 E3 ligase activity by direct mutation or with the use of small molecule inhibitors increased GSDMD level and cell death during pyroptosis. Our findings reveal that RING1 dictates GSDMD-mediated inflammatory response and host susceptibility to pathogen infection, highlighting RING1 as a potential therapeutic target for combating infectious diseases.

The relationship between anxiety symptoms and gastrointestinal symptoms in gastroenterology outpatients aged 6 to 18 years with the mediating role of sleep quality

Anxiety, a significant public health concern, frequently affects pediatric patients aged 6-18. This study seeks to examine the association between anxiety symptoms and gastrointestinal(GI) symptoms in patients within this age range who are visiting gastroenterology outpatient clinics. Additionally, we delve into whether sleep quality play a mediating role in this relationship. A cross-sectional analysis was conducted among 226 pediatric patients aged 6 and 18, who were recruited from the gastroenterology department of the Affiliated hospital of Xuzhou Medical University. Data were collected using a customized questionnaire that covered demographic information, clinical characteristics, and various self-assessment scales. To explore the association between GI symptoms and anxiety symptoms, a multivariate linear regression model was constructed. Additionally, we investigate the mediating role of sleep quality in this relationship. After accounting for key demographic and clinical factors, the intensity of GI symptoms exhibited a positive correlation with anxiety symptoms (β = 0.098, 95% CI: 0.070-0.137, p < 0.001). Furthermore, mediation analysis revealed that sleep quality partially mediated the relationship between the severity of GI symptoms and anxiety symptoms, contributing to a mediation effect of 11.13%. In pediatric patients aged 6-18, more severe GI symptoms were associated with a higher prevalence of anxiety symptoms, which in turn were linked to poorer sleep quality. It is advisable to incorporate assessments of sleep issues into the standard evaluation for pediatric patients in this age group visiting gastroenterology outpatient departments. Findings suggest that interventions targeting sleep quality may help manage GI symptoms, though longitudinal studies are needed to confirm causality.

Transcription factor ELF-1 protects against colitis by maintaining intestinal epithelium homeostasis

Inflammatory bowel disease (IBD) is a chronic, relapsing, and remitting disease characterized by chronic inflammation in the gastrointestinal tract. The exact etiology and pathogenesis of IBD remain elusive. Although ELF-1 has been known to be highly expressed in epithelial cells for past twenty years, little is known about its function in epithelial cells and epithelial-related IBD. Here, we demonstrated that ELF-1 deficiency in mouse lead to exacerbated DSS-induced colitis, marked by inflammation dominated by neutrophil infiltration and activation of IL-17 signaling pathways in various immune cells, including Th17, ILC3, γδT and NKT cells. Bone marrow transfer experiments confirmed ELF-1 deficiency in non-hematopoietic cells intrinsically worsened DSS-induced colitis. On one hand, ELF-1 deficiency enhanced the production of pro-inflammatory chemokines in colonic epithelial cells, leading to extensive infiltration of neutrophils and other immune cells into the colonic mucosal tissue. On the other hand, ELF-1 directly regulated the expression of the Rack1 gene in colonic epithelial tissue, which has been proved to play critical roles in maintaining intestinal homeostasis. Altogether, ELF-1 plays a protective role in colitis by maintaining intestinal epithelium homeostasis.

Noninvasive Detection and Monitoring of the Integrity of the Intestinal Barrier through NIR-II Fluorescence Imaging and Colorimetric Urinalysis

The variation of the integrity of the intestinal barrier is closely related to the occurrence and progression of various diseases, making its accurate detection and monitoring essential to provide reliable information for guiding the refinement of treatment scenarios. Herein, we developed a strategy utilizing glutathione-capped gold clusters (Au-GSH) to achieve simultaneous in vivo second near-infrared (NIR-II) fluorescence imaging and in vitro colorimetric urinalysis for noninvasive detection and monitoring of intestinal barrier integrity. After oral administration, Au-GSH can demonstrate different distribution behaviors in terms of the variation of intestinal barrier integrity. Specifically, Au-GSH could selectively permeate through compromised intestinal barrier to be distributed into the bladder in view of its ultrasmall size below the glomerular filtration cutoff, leading to the rapid excretion through urine. Such process can be visually profiled by collecting NIR-II fluorescence (>1100 nm) emitting from Au-GSH in a noninvasive real-time manner. By virtue of the peroxidase-like activity of Au-GSH, the simple colorimetric urinalysis was further established for evaluating the integrity of the intestinal barrier, advancing the detection and monitoring performance. As a result, our developed strategy successfully detected the damage of intestinal barrier integrity in ulcerative colitis (UC) mice, a common disease characterized by compromised intestinal barrier integrity. Excitingly, the monitoring of restoration of intestinal barrier integrity in both therapeutic and preventative modes for UC mice was also realized by our strategy, making it a promising diagnosis scenario for diseases related to the variation of intestinal barrier integrity.

Sedanolide alleviates DSS-induced colitis by modulating the intestinal FXR-SMPD3 pathway in mice

INTRODUCTION

Inflammatory bowel disease (IBD) is a global disease with limited therapy. It is reported that sedanolide exerts anti-oxidative and anti-inflammatory effects as a natural phthalide, but its effects on IBD remain unclear.

OBJECTIVES

In this study, we investigated the impacts of sedanolide on dextran sodium sulfate (DSS)-induced colitis in mice.

METHODS

The mice were administered sedanolide or vehicle followed by DSS administration, after which colitis symptoms, inflammation levels, and intestinal barrier function were evaluated. Transcriptome analysis, 16S rRNA sequencing, and targeted metabolomics analysis of bile acids and lipids were performed.

RESULTS

Sedanolide protected mice from DSS-induced colitis, suppressed the inflammation, restored the weakened epithelial barrier, and modified the gut microbiota by decreasing bile salt hydrolase (BSH)-expressing bacteria. The downregulation of BSH activity by sedanolide increased the ratio of conjugated/unconjugated bile acids (BAs), thereby inhibiting the intestinal farnesoid X receptor (FXR) pathway. The roles of the FXR pathway and gut microbiota were verified using an intestinal FXR-specific agonist (fexaramine) and germ-free mice, respectively. Furthermore, we identified the key effector ceramide, which is regulated by sphingomyelin phosphodiesterase 3 (SMPD3). The protective effects of ceramide (d18:1/16:0) against inflammation and the gut barrier were demonstrated in vitro using the human cell line Caco-2.

CONCLUSION

Sedanolide could reshape the intestinal flora and influence BA composition, thus inhibiting the FXR-SMPD3 pathway to stimulate the synthesis of ceramide, which ultimately alleviated DSS-induced colitis in mice. Overall, our research revealed the protective effects of sedanolide against DSS-induced colitis in mice, which indicated that sedanolide may be a clinical treatment for colitis. Additionally, the key lipid ceramide (d18:1/16:0) was shown to mediate the protective effects of sedanolide, providing new insight into the associations between colitis and lipid metabolites.

Exploring the therapeutic potential of Xiangsha Liujunzi Wan in Crohn's disease: from network pharmacology approach to experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Xiangsha Liujunzi Wan (LJZW) is a traditional Chinese medicine (TCM) formula containing a variety of traditional Chinese herb components. Its principal components are often used in the treatment of gastrointestinal diseases and contribute to the treatment of Crohn's disease (CD).

AIM OF THE STUDY

To explore the therapeutic potential of LJZW in CD through network pharmacology, bioinformatics, molecular docking, and experimental verification.

METHODS

The principal bioactive components and corresponding targets of LJZW were ascertained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Potential targets for CD were identified in GeneCards, OMIM, DrugBank, DisGeNET, CTD, and Gene Expression Omnibus (GEO) databases. Intersection targets of LJZW and CD were identified using a Venn diagram and visualized using Cytoscape 3.8.0 to construct a protein-protein interaction (PPI) network. Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were employed to assess the function of intersection targets. AutoDockTools and PyMOL were used for molecular docking to recognize the association between the core ingredients of LJZW and the core targets of CD. Subsequently, a series of experiments were conducted for validation.

RESULTS

The network pharmacology results indicated that there were 156 bioactive components and 268 corresponding targets for LJZW, 3023 primary relevant targets for CD, and 169 intersection targets for LJZW and CD. The PPI network was employed to identify five hub genes and six clusters. The GO functional analysis indicated that intersection targets are primarily correlated with oxidative stress and inflammatory responses. KEGG pathway analysis revealed that these targets were primarily associated with the phosphotylinosital 3 kinase (PI3K)-protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) signaling pathways. The molecular docking results showed that the core ingredients of LJZW had good binding ability with the core targets of CD. A series of experiments demonstrated that LJZW could effectively attenuate TNBS-induced colitis symptoms, inhibit the inflammatory response, and protect intestinal barrier function by inhibiting the PI3K-AKT and MAPK signaling pathways, thus preventing and treating CD.

CONCLUSION

LJZW has the characteristics of multi-component, multi-target, and multi-pathway treatment, which helps to improve the treatment of CD, protect the intestinal barrier, and exert the effect of anti-inflammatory therapy by inhibiting PI3K-AKT and MAPK signaling pathways.

Vitamin K2 alleviates dextran sulfate sodium-induced colitis via inflammatory responses, gut barrier integrity, and the gut microbiota in mice

Vitamin K2 (VK2) has been shown to have potential benefits in improving intestinal integrity, but its potential and mechanisms for alleviating intestinal inflammation are still unclear. The present results showed that VK2 supplementation significantly alleviated the symptoms of colitis and maintained the intestinal barrier integrity. In addition, VK2 significantly down-regulated the mRNA expression levels of pro-inflammatory cytokines including IL-1β, IL-6, and TNF-α, while up-regulated the mRNA expression level of anti-inflammatory cytokines such as IL-10. Moreover, VK2 significantly alleviated DSS-induced intestinal epithelial barrier dysfunction by maintaining the tight junction function. Furthermore, VK2 also regulated DSS-induced gut microbiota dysbiosis by reshaping the structure of gut microbiota, such as increasing the relative abundance of Firmicutes, Euryarchaeota, Prevotellaceae, and Prevotella and reducing the relative abundance of Proteobacteria, Rikenellaceae, Enterobacteriaceae, Acetatifactor, and Alistioes. In conclusion, these results indicated that VK2 effectively alleviates DSS-induced colitis in mice by modulating the gut microbiota.

The potential of EGCG in modulating the oral-gut axis microbiota for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a recurrent chronic intestinal disorder that includes ulcerative colitis (UC) and Crohn's disease (CD). Its pathogenesis involves intricate interactions between pathogenic microorganisms, native intestinal microorganisms, and the intestinal immune system via the oral-gut axis. The strong correlation observed between oral diseases and IBD indicates the potential involvement of oral pathogenic microorganisms in IBD development. Consequently, therapeutic strategies targeting the proliferation, translocation, intestinal colonization and exacerbated intestinal inflammation of oral microorganisms within the oral-gut axis may partially alleviate IBD. Tea consumption has been identified as a contributing factor in reducing IBD, with epigallocatechin gallate (EGCG) being the primary bioactive compound used for IBD treatment. However, the precise mechanism by which EGCG mediates microbial crosstalk within the oral-gut axis remains unclear. In this review, we provide a comprehensive overview of the diverse oral microorganisms implicated in the pathogenesis of IBD and elucidate their colonization pathways and mechanisms. Subsequently, we investigated the antibacterial properties of EGCG and its potential to attenuate microbial translocation and colonization in the gut, emphasizing its role in attenuating exacerbations of IBD. We also elucidated the toxic and side effects of EGCG. Finally, we discuss current strategies for enhancing EGCG bioavailability and propose novel multi-targeted nano-delivery systems for the more efficacious management of IBD. This review elucidates the role and feasibility of EGCG-mediated modulation of the oral-gut axis microbiota in the management of IBD, contributing to a better understanding of the mechanism of action of EGCG in the treatment of IBD and the development of prospective treatment strategies.

Mechanism of Nicotiflorin in San-Ye-Qing rhizome for anti-inflammatory effect in ulcerative colitis

BACKGROUND

The incidence of ulcerative colitis (UC) is on the rise globally and the development of drugs targeting UC is urgent. Finding the target of action of natural products is important for drug discovery, elucidation of drug action mechanism, and disease mechanism. San-Ye-Qing (SYQ), is an ancient herbal medicine, but whether the powder of its rhizome has pharmacological effects against UC and its mechanism of action are not clear.

PURPOSE

To evaluate the therapeutic effectiveness of rhizome powder of SYQ in treating UC, and conduct an isolation and characterization of the chemical constituents of the powder. Further, screen the most potent compounds among them and determine the potential mechanism for treating UC.

METHODS

In vivo, the therapeutic effect of SYQ's rhizome powder on UC was assessed by mice's body weight, DAI score, colon length, tissue MPO activity, serum inflammatory markers, etc. Additionally, HPLC was used to isolate and identify the specific chemical components of SYQ's rhizome powder. Then, the most effective compounds and their therapeutic targets were analysed and screened in SYQ rhizome powder using network pharmacology, combined with CCK-8 assay, NO release assay and molecular docking assay, in conjunction with CETSA, DARTS, SPR and enzyme activity assay. Finally, the biological effects of the key compound on the targets were validated using Western blot and ELISA.

RESULTS

In vivo, SYQ rhizome powder effectively restored mice's body weight, lowered DAI and pathological score, downregulated the expression of inflammatory biomarkers, and restored colon length, as well as the colonic epithelial and mucus barriers. Afterward, 9 compounds were isolated and identified from the powder of the rhizomes of SYQ by HPLC. Nicotiflorin is the primary compound in SYQ with the highest concentration. According to both CCK-8 and NO release tests, Nicotiflorin is also the most efficacious compound. Combined with network pharmacological prediction, molecular docking analysis, CETSA, DARTS, SPR and enzyme activity assay, Nicotiflorin may ultimately suppress inflammation by targeting p65 and inhibiting the NF-κB pathway, thereby attenuating the activation of NLRP3 inflammasome. To verify this conclusion, Western blot and ELISA experiments were conducted.

CONCLUSIONS

Our results suggest that the extract from SYQ rhizomes has therapeutic properties for UC. Its active ingredient Nicotiflorin exerted potent anti-UC effects by binding to p65 and inhibiting the activation of NF-κB and NLRP3 inflammasomes.

Houttuynia cordata thunb. alleviates inflammatory bowel disease by modulating intestinal microenvironment: a research review

Inflammatory bowel disease (IBD) is a complex group of chronic intestinal diseases, the cause of which has not yet been clarified, but it is widely believed that the disorder of the intestinal microenvironment and its related functional changes are key factors in the development of the disease. Houttuynia cordata thunb. is a traditional plant with abundant resources and long history of utilization in China, which has attracted widespread attention in recent years due to its potential in the treatment of IBD. However, its development and utilization are limited owing to the aristolochic acid alkaloids contained in it. Therefore, based on the relationship between the intestinal microenvironment and IBD, this article summarizes the potential mechanisms by which the main active ingredients of Houttuynia cordata thunb., such as volatile oils, polysaccharides, and flavonoids, and related traditional Chinese medicine preparations, such as Xiezhuo Jiedu Formula, alleviate IBD by regulating the intestinal microenvironment. At the same time, combined with current reports, the medicinal and edible safety of Houttuynia cordata thunb. is explained for providing ideas for further research and development of Houttuynia chordate thunb. in IBD disease, more treatment options for IBD patients, and more insights into the therapeutic potential of plants with homology of medicine and food in intestinal diseases, and even more diseases.