EZH2 Regulates Intestinal Inflammation and Necroptosis Through the JNK Signaling Pathway in Intestinal Epithelial Cells.

BACKGROUND: Inflammatory bowel disease (IBD) is a common disorder of chronic intestinal inflammation that can be caused by the disruption of intestinal immune homeostasis. AIM: We aimed to evaluate the role of enhancer of zeste homolog 2 (EZH2) in the inflammatory response and explore the association between EZH2 and necroptosis in human epithelial colorectal adenocarcinoma cell lines. METHODS: In both in vitro and in vivo models, expression of EZH2 in intestinal tissues was verified by histology. The expression of inflammatory cytokines in cell lines treated with EZH2 siRNA with or without stimulus was analyzed by quantitative real-time polymerase chain reaction. An intestinal necroptosis cell model was established to elucidate whether EZH2 is involved in necroptosis. RESULTS: Our present data indicated that EZH2 expression was decreased in in vitro and in vivo models and in patients with inflammatory bowel disease. EZH2 downregulation increased the expression of inflammatory factors, including TNF-α, IL-8, IL-17, CCL5, and CCL20 in a Caco-2 cell model. The JNK pathway was activated with the reduction of EZH2. In the necroptosis model, downregulation of EZH2 was detected with the upregulation of necroptotic markers RIP1 and RIP3. In addition, EZH2 knockdown with siRNA increased p-JNK and p-c-Jun. CONCLUSION: Our data suggest that EZH2 plays an important role in the development of intestinal inflammation and necroptosis. Hence, EZH2 could be a potential therapeutic target for IBD.

Nuclear Receptors in the Pathogenesis and Management of Inflammatory Bowel Disease.

Nuclear receptors (NRs) are ligand-dependent transcription factors that regulate the transcription of target genes. Previous epidemiological and genetic studies have documented the association of NRs with the risk of inflammatory bowel disease (IBD). Although the mechanisms of action of NRs in IBD have not been fully established, accumulating evidence has demonstrated that NRs play complicated roles in regulating intestinal immunity, mucosal barriers, and intestinal flora. As one of the first-line medications for the treatment of IBD, 5-aminosalicylic acid (5-ASA) activates peroxisome proliferator-activated receptor gamma (PPARγ) to attenuate colitis. The protective roles of rifaximin and rifampicin partly depend on promoting pregnane X receptor (PXR) expression. The aims of this review are to discuss the roles of several important NRs, such as PPARγ, PXR, vitamin D receptor (VDR), farnesoid X receptor (FXR), and RAR-related orphan receptor gammat (RORγt), in the pathogenesis of IBD and management strategies based on targeting these receptors.

Dysregulated Up-Frameshift Protein 1 Promotes Ulcerative Colitis Pathogenesis Through the TNFR1-NF-κB/MAPKs Pathway.

BACKGROUND: Ulcerative colitis (UC) is an idiopathic colonic mucosal disease, and its pathogenesis has not been fully understood. Up-frameshift protein 1 (UPF1) is a potential molecule for UC predicted by a computational approach. AIM: The present study aimed to validate the underlying mechanism of UPF1 in UC. METHODS: UPF1 expression was detected by qRT-PCR, western blotting, and immunohistochemistry in dextran sulfate sodium-induced colitis in mice. To simulate the intestinal inflammation microenvironment, NCM460 human colonic epithelial cells were exposed to a mixture of inflammatory mediators. The potential mechanism involving TNFR1-NF-κB/MAPKs pathway activation was addressed by western blotting, reporter gene assays, and siRNA (siUPF1) or UPF1-expressing plasmid pENTER-transfected cells. RESULTS: UPF1 was downregulated in colonic epithelial cells of colitic mice, and in vitro, contrary to the mRNA levels of the associated cytokines enhanced in the UPF1 dysregulation group within stimulatory factors, most relevant cytokines were significantly decreased in UPF1 overexpression group. Mechanistically, the increased expression of tumor necrosis factor receptor 1 (TNFR1) was found in NCM460 cells pre-treated with siUPF1, with the activation of IKK/NF-κB and MAPKs pathways, including JNK/AP-1 and P38, but not the ERK1/2 pathway. Moreover, the repression of TNFR1 required the interaction of UPF1 with the promoter. CONCLUSION: UPF1, which negatively regulated the transcription of TNFR1, is a novel factor regulating intestinal inflammation. The downregulation of UPF1 activated the TNFR1-dependent NF-κB/MAPKs pathway, and promoting inflammatory responses in colon might act as a causal role in UC.

Diagnosis and Treatment of Duodenal Gastrointestinal Stromal Tumors.

OBJECTIVES: The diagnostic value of different noninvasive diagnostic modalities and the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) reliability of duodenal gastrointestinal stromal tumors (GISTs) are ambiguous in the present studies. METHODS: Patients with a histopathological diagnosis of the primary duodenal GISTs between the years 2008 and 2018 were analyzed. Data on the treatment and clinicopathological features were recorded. Furthermore, the computed tomography (CT)/magnetic resonance imaging (MRI), EUS, and EUS-FNA results were collected and compared. RESULTS: A total of 142 patients were enrolled into the study. In all patients, the most common symptom was gastrointestinal bleeding (44.4%), followed by abdominal pain and bloating (27.5%). Duodenal GISTs were mostly located in the second duodenal portion (52.1%), followed by the first portion (19.0%). EUS had significantly higher sensitivity and positive predictive values than CT or MRI (P = 0.047 and P = 0.005, respectively). The EUS-FNA sensitivity of duodenal GISTs was also significantly higher than the conventional endoscopic biopsy (73.3% vs 33.3%, P = 0.006). A total of 131 patients underwent surgery, including limited resection or pancreaticoduodenectomy. The tumor size and postoperative complication rates were higher in patients who underwent pancreaticoduodenectomy (P = 0.001 and P < 0.001, respectively). DISCUSSION: The diagnostic value of EUS is significantly higher than that of CT and MRI for duodenal GISTs. The EUS-FNA can provide a histological diagnosis of duodenal GISTs in most cases.

Inhibition of Histone Deacetylation by MS-275 Alleviates Colitis by Activating the Vitamin D Receptor.

BACKGROUND: Ulcerative colitis [UC] is a common chronic inflammatory bowel disease without curative treatment. METHODS: We conducted gene set enrichment analysis to explore potential therapeutic agents for UC. Human colon tissue samples were collected to test H3 acetylation in UC. Both in vivo and in vitro colitis models were constructed to verify the role and mechanism of H3 acetylation modification in UC. Intestine-specific vitamin D receptor [VDR]-/- mice and VD [vitamin D]-deficient diet-fed mice were used to explore downstream molecular mechanisms accordingly. RESULTS: According to the Connectivity Map database, MS-275 [class I histone deacetylase inhibitor] was the top-ranked agent, indicating the potential importance of histone acetylation in the pathogenesis of UC. We then found that histone H3 acetylation was significantly lower in the colon epithelium of UC patients and negatively associated with disease severity. MS-275 treatment inhibited histone H3 deacetylation, subsequently attenuating nuclear factor kappa B [NF-κB]-induced inflammation, reducing cellular apoptosis, maintaining epithelial barrier function, and thereby reducing colitis activity in a mouse model of colitis. We also identified VDR as be a downstream effector of MS-275. The curative effect of MS-275 on colitis was abolished in VDR-/- mice and in VD-deficient diet-fed mice and VDR directly targeted p65. In UC patients, histone H3 acetylation, VDR and zonulin-1 expression showed similar downregulation patterns and were negatively associated with disease severity. CONCLUSIONS: We demonstrate that MS-275 inhibits histone deacetylation and alleviates colitis by ameliorating inflammation, reducing apoptosis, and maintaining intestinal epithelial barrier via VDR, providing new strategies for UC treatment.

Serum proteome profiles to differentiate Crohn disease from intestinal tuberculosis and primary intestinal lymphoma: A pilot study.

The differential diagnosis of Crohn disease (CD) from intestinal tuberculosis (ITB) and primary intestinal lymphoma (PIL) is challenging in patients who exhibit atypical clinical characteristics. The aim of the present study was to explore the serum proteome profiles of CD, PIL and ITB and to identify their differentiations.Treatment-naïve patients with CD (n = 10), PIL (n = 10) and ITB (n = 10) were enrolled in the present study. Differentially expressed proteins (DEPs) in patient serum samples were compared between groups using tandem mass tag labeled proteomic technology. A principal component analysis (PCA) plot and volcano maps were also visualized. Functional pathway analysis was performed using Reactome. The Area under the Curve (AUC) was calculated for each DEP.A total of 818 proteins were identified through proteomic quantification. Among them, 108 DEPs were identified to be differentiated between CD and ITB, 105 proteins between CD and PIL and 55 proteins between ITB and PIL. The proteome from the three groups was distinguishable in the PCA plot. The results revealed that 19, 12, and 10 proteins (AUC ≥ 0.95) were differentially expressed between CD and PIL, CD and ITB, and PIL and ITB, respectively. Among these DEPs, tumor necrosis factor ligand superfamily member 13 was higher in CD than in ITB and PIL. Peroxiredoxin-5, T-complex protein 1 subunit Gamma, CutA, and Fibulin-5 were increased in CD and PIL when compared with ITB. The levels of fibrinogen chains were also significantly higher in patients with PIL compared with CD.The current study demonstrated that serum proteome was distinguishable among patients with CD, PIL, and ITB. The identified proteins may assist in the clinical differentiation among them.

Multiple gastric angiolipomas: A case report.

BACKGROUND: Angiolipoma is a benign tumor and is generally found in subcutaneous tissues. Angiolipomas are rare in the gastrointestinal tract, including the stomach. Preoperative diagnosis of the tumor is difficult, although there are several radiological examinations such as computed tomography and endoscopic ultrasound. CASE SUMMARY: We report a 24-year-old Chinese man with multiple gastric angiolipomas, with a positive stool occult blood examination. Endoscopic biopsy only showed nonspecific inflammation. Histological examination of the specimen by endoscopic snare resection showed that the tumor consisted of adipose tissues and blood vessels. We also performed a literature review. After the use of proton pump inhibitor, the fecal occult blood test was negative. Due to the difficulty of resecting multiple lesions in the stomach completely and the benign characteristics of angiolipoma, we chose to have regular upper gastrointestinal endoscopy evaluation of the lesion. No evidence of significant change in lesion size was detected after 3-years follow-up. CONCLUSION: Gastric angiolipoma is rare, and benign neoplasm should be considered when lesions occur submucosally in the gastrointestinal tract.

Association between Helicobacter pylori infection and nonalcoholic fatty liver disease: a systemic review and meta-analysis.

Although clinical studies have shown possible links of Helicobacter pylori infection with the development of nonalcoholic fatty liver disease (NAFLD), the results remain controversial. The aim of this meta-analysis is to investigate the association between H. pylori infection and NAFLD. A comprehensive search of relevant studies was performed up to November 2018. Data on H. pylori infection in NAFLD patients and controls were extracted. Odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model. Twelve studies involving 27 400 NAFLD patients and 60 347 controls were included. The pooled overall OR of H. pylori infection in NAFLD patients compared with controls was 1.36 (95% CI: 1.22-1.53, I=89.6%, P=0.000). Meta-regression and subgroup analysis showed that the sample size and the case-control ratio may have accounted for some of the heterogeneity. When stratified by publication year, the diagnostic method used for H. pylori, and Newcastle-Ottawa Scale scores, the OR remained significant. However, possible publication bias was observed. Of the 12 studies, six had carried out multivariable analysis after adjusting for potential confounders. The pooled results from these studies still indicated a higher risk of NAFLD in patients infected with H. pylori (OR=1.17, 95% CI: 1.01-1.36, I=72.4%, P=0.003). There is a 36% increased risk of NAFLD in patients with H. pylori infection. Further studies are warranted to investigate whether eradication of H. pylori is useful in the prevention and treatment of NAFLD.

Quantitative Proteomic Analysis Reveals the Deregulation of Nicotinamide Adenine Dinucleotide Metabolism and CD38 in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) has become a major health challenge worldwide. However, the precise etiological and pathophysiological factors involved in IBD remain unclear. Proteomics can be used for large-scale protein identification analysis. In the current study, using tandem mass tag- (TMT-) based shotgun proteomics, proteomic differences between intestinal tissue from health controls, patients with Crohn's disease (CD), and patients with ulcerative colitis (UC) were compared. Proteins with fold change >2 or <0.5 and P value < 0.05 between groups were considered differentially expressed. ProteinAtlas was used to analyze the tissue specificity of differentially expressed proteins (DEPs). Reactome pathway analysis was applied to cluster functional pathways. A total of 4786 proteins were identified, with 59 proteins showing higher levels and 43 showing lower levels in patients with IBD than in controls. Seventeen proteins, including angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme 1 (ACE), showed higher levels in CD than in UC. Several novel proteins such as CD38, chitinase 3-like 1 (CHI3L1), olfactomedin 4 (OLFM4), and intelectin 1 were screened out between patients with IBD and controls. When proteins with fold change >1.2 or <0.84 and P value < 0.05 between groups were considered differentially expressed, the expression of 10 proteins, including CD38, involved in the nicotinamide adenine dinucleotide (NAD) metabolism and signaling pathway showed significant changes in IBD. Using the NCBI GEO database, we confirmed increased CD38 mRNA expression in patients with UC and in mouse colitis models. Protein CD38 expression was higher in CD and UC than in normal controls. CD38 expression was higher in inflamed tissues than in noninflamed tissues, and CD38 was located in F4/80-positive cells. Our study may provide novel insights into the molecular pathogenesis of IBD. Further studies are required on the role of NAD metabolism and CD38 in intestinal inflammation.

Necroptosis in inflammatory bowel disease and other intestinal diseases.

For a long time, it was believed that apoptosis and necrosis were the main pathways for cell death, but a growing body of research has shown that there are other pathways. Among these, necroptosis, a regulatory caspase-independent, programmed cell death pathway, is supposed to be of importance in the pathogenesis of many diseases. The mechanism of regulating, inducing and blocking necroptosis is a complex process that involves expression and regulation of a series of molecules including receptor interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase like protein. By blocking or downregulating expression of key molecules in the necroptotic pathway, intestinal inflammation can be affected to some extent. In this paper, we introduce the concept of necroptosis, its main pathway, and its impact on the pathogenesis of inflammatory bowel disease (IBD) and other intestinal diseases, to explore new drug targets for intestinal diseases, including IBD.