Cytolethal distending toxin (CDT) produced by Campylobacter jejuni comprises a heterotrimeric complex formed by CdtA, CdtB, and CdtC. Among these toxin subunits, CdtA and CdtC function as essential proteins that mediate toxin binding to cytoplasmic membranes followed by delivery of CdtB into the nucleus. The binding of CdtA/CdtC to the cell surface is mediated by cholesterol, a major component in lipid rafts. Although the putative cholesterol recognition/interaction amino acid consensus (CRAC) domain of CDT has been reported from several bacterial pathogens, the protein regions contributing to CDT binding to cholesterol in C. jejuni remain unclear. Here, we selected a potential CRAC-like region present in the CdtC from C. jejuni for analysis. Molecular modeling showed that the predicted functional domain had the shape of a hydrophobic groove, facilitating cholesterol localization to this domain. Mutation of a tyrosine residue in the CRAC-like region decreased direct binding of CdtC to cholesterol rather than toxin intermolecular interactions and led to impaired CDT intoxication. These results provide a molecular link between C. jejuni CdtC and membrane-lipid rafts through the CRAC-like region, which contributes to toxin recognition and interaction with cholesterol.

The incidence and prevalence of inflammatory bowel disease (IBD) are low but increasing in Taiwan. We aimed to investigate the epidemiology and clinical outcomes of IBD in central Taiwan. We retrospectively analyzed patients with IBD diagnosed at our hospital between January 2000 and September 2018. The diagnostic criteria were based on endoscopic and pathologic findings. Clinical characteristics, treatment regimens, and treatment outcomes were analyzed. A total of 190 patients with IBD were enrolled (80 with Crohn’s disease (CD) and 110 with ulcerative colitis (UC)). The mean age at diagnosis was 38.4 years (CD: 36 years, UC: 40 years). Male patients accounted for the majority of patients (71.1%). The male-to-female ratio was 3 : 1 for CD and 2.1 : 1 for UC. Current and ever smokers accounted for 30.5% of all patients. Only 4.2% of patients had a family history of IBD. Extraintestinal manifestations (EIMs) were reported in 7.9%, and colorectal cancers (CRCs) were reported in 2.1% of all patients. In patients with CD, the ileal type was the most common disease phenotype (57.5%), and the stricturing type was the most common disease behavior (60.0%). In patients with UC, left-sided colitis was the predominant disease extent (42.7%). The seroprevalence of hepatitis B virus (HBV) was 13.3%. The incidence of perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) in patients with UC was 22%. 5-Aminosalicylic acids were the preferred treatment for UC, whereas corticosteroids, immunomodulators, and biologic agents were preferred for CD. In patients with CD, the bowel resection rate was 38.8%, and the incidence of hip avascular necrosis was 3.8%. In Taiwan, patients with IBD showed a male predominance, lack of familial clustering, a higher prevalence of HBV infection, and a lower prevalence of p-ANCA, EIMs, and CRC. Moreover, a higher incidence of the ileal type with poor outcomes of CD and left-sided predominance in UC were found.

Background: Neoadjuvant chemoradiotherapy (NCRT) followed by surgery is the standard treatment for patients with locally advanced rectal cancer. This study developed a random forest (RF) model to predict pathological complete response (pCR) based on radiomics derived from baseline 18 F-fluorodeoxyglucose ([ 18 F] FDG)-positron emission tomography (PET)/computed tomography (CT).Methods: This study included 169 patients with newly diagnosed rectal cancer. All patients received 18 F[FDG]-PET/CT, NCRT, and surgery. In total, 68 radiomic features were extracted from the metabolic tumor volume. The numbers of splits in a decision tree and trees in an RF were determined based on their effects on predictive performance. Receiver operating characteristic curve analysis was performed to evaluate predictive performance and ascertain the optimal threshold for maximizing prediction accuracy.Results: After NCRT, 22 patients (13%) achieved pCR, and 42 features that could differentiate tumors with pCR were used to construct the RF model. Six decision trees and seven splits were suitable. Accordingly, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 81.8%, 97.3%, 81.8%, 97.3%, and 95.3%, respectively. Conclusions: By using an RF, we determined that radiomics derived from baseline 18 F[FDG]-PET/CT could accurately predict pCR in patients with rectal cancer. Highly accurate and predictive values can be achieved but should be externally validated.

Helicobacter pylori colonizes human gastric epithelial cells and contributes to the development of several gastrointestinal disorders. Interleukin (IL)-33 is involved in various immune responses, with reported proinflammatory and anti-inflammatory effects, which may be associated with colitis and colitis-associated cancer. IL-33 induces the inflammatory cascade through its receptor, suppression of tumorigenicity-2 (ST-2). Binding of IL-33 to membrane-bound ST-2 (mST-2) recruits the IL-1 receptor accessory protein (IL-1RAcP) and activates intracellular signaling pathways. However, whether IL-33/ST-2 is triggered by H. pylori infection and whether this interaction occurs in lipid rafts remain unclear. Our study showed that both IL-33 and ST-2 expression levels were significantly elevated in H. pylori-infected cells. Confocal microscopy showed that ST-2 mobilized into the membrane lipid rafts during infection. Depletion of membrane cholesterol dampened H. pylori-induced IL-33 and IL-8 production. Furthermore, in vivo studies revealed IL-33/ST-2 upregulation, and severe leukocyte infiltration was observed in gastric tissues infected with H. pylori. Together, these results demonstrate that ST-2 recruitment into the lipid rafts serves as a platform for IL-33-dependent H. pylori infection, which aggravates inflammation in the stomach.

The receptor for advanced glycation end products (RAGE) interacts with various molecules in the cell membrane to induce an inflammatory response. The cytolethal distending toxin (CDT) produced by Campylobacter jejuni contains three subunits: CdtA, CdtB, and CdtC. Amongst, CdtA and CdtC interact with membrane lipid rafts, by which CdtB enters the nucleus to induce pathogenesis. In this study, we first explored the relationships between RAGE, lipid rafts, and inflammation in gastrointestinal epithelial cells exposed to CDT. Our results showed that CDT activated the expression of RAGE and high mobility group box 1 (HMGB1), followed by the recruitment of RAGE into lipid rafts. In contrast, RAGE antagonist inhibited CDT-induced inflammation via the RAGE-HMGB1 axis. Disruption of lipid rafts decreased CDT-induced downstream signaling, which in turn attenuated the inflammatory response. Furthermore, in vivo studies revealed severe inflammation and upregulation of RAGE and IL-1β in the intestinal tissues of CDT-treated mice. These results demonstrate that mobilization of RAGE to lipid rafts plays a crucial role in CDT-induced inflammation.

Conventionally, statins are used to treat high cholesterol levels. They exhibit pleiotropic effects, such as the prevention of cardiovascular disease and decreased cancer mortality. Gastric cancer (GC) is one of the most common cancers, ranking as the third leading global cause of cancer-related deaths, and is mainly attributed to chronic Helicobacter pylori infection. During their co-evolution with hosts, H. pylori has developed the ability to use the cellular components of the host to evade the immune system and multiply in intracellular niches. Certain H. pylori virulence factors, including cytotoxin-associated gene A (CagA), vacuolating cytotoxin A (VacA), and cholesterol-α-glucosyltransferase (CGT), have been shown to exploit host cholesterol during pathogenesis. Therefore, using statins to antagonize cholesterol synthesis might prove to be an ideal strategy for reducing the occurrence of H. pylori-related GC. This review discusses the current understanding of the interplay of H. pylori virulence factors with cholesterol and reactive oxygen species (ROS) production, which may prove to be novel therapeutic targets for the development of effective treatment strategies against H. pylori-associated GC. We also summarize the findings of several clinical studies on the association between statin therapy and the development of GC, especially in terms of cancer risk and mortality.

The bacterial pathogen Helicobacter pylori (Hp) is the leading risk factor for the development of gastric cancer. Hp virulence factor, cytotoxin-associated gene A (CagA) interacted with cholesterol-enriched microdomains and leads to induction of inflammation in gastric epithelial cells (AGS). In this study, we identified a triterpenoid methylantcinate B (MAB) from the medicinal mushroom Antrodia camphorata which inhibited the translocation and phosphorylation of CagA and caused a reduction in hummingbird phenotype in HP-infected AGS cells. Additionally, MAB suppressed the Hp-induced inflammatory response by attenuation of NF-κB activation, translocation of p65 NF-κB, and phosphorylation of IκB-α, indicating that MAB modulates CagA-mediated signaling pathway. Additionally, MAB also suppressed the IL-8 luciferase activity and its secretion in HP-infected AGS cells. On the other hand, molecular structure simulations revealed that MAB interacts with CagA similarly to that of cholesterol. Moreover, binding of cholesterol to the immobilized CagA was inhibited by increased levels of MAB. Our results demonstrate that MAB is the first natural triterpenoid which competes with cholesterol bound to CagA leading to attenuation of Hp-induced pathogenesis of epithelial cells. Thus, this study indicates that MAB may have a scope to develop as a therapeutic candidate against Hp CagA-induced inflammation.

Diabetes mellitus is associated with a high risk of developing gastric cancer (GC). Metformin, which is conventionally used to treat type 2 diabetes, induces AMP-activated protein kinase signaling and suppresses gluconeogenesis. Recent studies have reported that metformin is associated with beneficial effects in cancer prevention and treatment owing to its anti-tumor effects. This makes metformin a potential medication for GC therapy. However, contradicting reports have emerged regarding the efficacy of metformin in reducing the risk of GC. This review summarizes the impact of metformin on mitigating GC risk by analyzing clinical databases. The mechanism underlying the anti-tumor effect of metformin on GC is also discussed.