In vivo anti-gastric ulcer activity of 7-O-methyl aromadendrin and sakuranetin via mitigating inflammatory and oxidative stress trails

ETHNOPHARMACOLOGICAL RELEVANCE

Eucalyptus genus has been used for a very long time in conventional treatment as an anti-ulcer remedy.

AIM OF THE STUDY

The study aimed to explore the gastroprotective potential of 7-O-methyl aromadendrin (7-OMA), and sakuranetin (SKN) in comparison with omeprazole. The study tackled the contribution of their anti-inflammatory, antioxidant, and antiapoptotic capabilities to their anti-gastric ulcer effects.

MATERIALS AND METHODS

An ethanol-induced gastric ulcer model in rats was adopted and the consequences were confirmed by a molecular docking study.

RESULTS

The oral pretreatment of rats 1 h before ethanol using omeprazole (20 mg/kg) or 7-OMA (20 or 40 mg/kg) or SKN (20 or 40 mg/kg) exhibited gastroprotective and anti-inflammatory properties to different extents. These amendments witnessed as restorations in the stomach histological architecture in H and E-stained sections, mucus content in periodic acid-Schiff (PAS) stained sections with increased cellular proliferation, as demonstrated by increased immunohistochemical staining of PCNA, and increments in stomach COX-1 activity and eNOS. The highest dose of SKN showed the best corrections to reach 4.8, 1.8, and 2.1 folds increase in PAS, COX-1 and eNOS, respectively as compared to the untreated ethanol-induced gastric ulcer group; effects that were comparable to that of omeprazole. Moreover, reductions in COX-2 activity, and the protein expression of NF-κB, IL-6, TNF-α and NOx, in addition to the gene expression of inducible iNOS were also noted. Moreover, the antioxidant and antiapoptotic capabilities of omeprazole, 7-OMA, and SKN were perceived. SKN (40 mg/kg) succeeded to show the unsurpassed results to reach 293.6%, 237.1%, 274.7%, 248.2%, and 175.4% in total and reduced GSH, catalase, SOD, and Bcl2, respectively, as well as 50.0%, 46.8%, and 52.1 % in oxidized GSSG, TBARS and caspase-3, respectively. The gastroprotective potential of the tested compounds can be assigned to their anti-inflammatory, antioxidant and antiapoptotic properties.7-OMA and SKN were studied using molecular docking into the binding sites of the most significant inflammatory targets, including COX-2, TNF-α, iNOS, and NF-κB. Pharmacokinetic and physicochemical parameters in silico were appropriate.

CONCLUSION

The prophylactic use of 7-OMA and SKN could be considered as an add-on to recurrent gastric ulcers and might influence its therapeutic approaches.

Gastroprotective effect of eupatilin, a polymethoxyflavone from Artemisia argyi H.Lév. & Vaniot, in ethanol-induced gastric mucosal injury via NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Artemisia argyi H.Lév. & Vaniot (AA) has been extensively utilized as an important medicine and food homology in China, Japan, Korea, and eastern parts of Russia, owing to its pharmacological effects, which include anti-inflammatory, antibacterial, antitussive, and antiallergic properties. Despite the extract of AA can significantly alleviate gastric mucosal injury, its precise material basis for effectiveness is not yet clear. As one of the polymethoxy flavonoids with high content in AA, the gastroprotective activity and molecular mechanism of eupatilin (EUP) require further investigation.

AIM OF THE STUDY

This study aims to investigate the gastroprotective effects and possible mechanisms of EUP by using an ethanol-induced gastric mucosal injury model in rats.

MATERIALS AND METHODS

EUP was isolated from 95% ethanol extract of AA using a systematic phytochemical method. The gastroprotective activity of EUP was evaluated using a male SD rat model with ethanol-induced gastric mucosa injury. Histopathology evaluation of gastric tissues was performed using hematoxylin and eosin (H&E) staining. The levels of cytokines in the plasma and tissues were tested using the ELISA kits, while western blot analysis was employed to assess the expressions of COX-2, iNOS, and NF-κB pathway proteins.

RESULTS

A sufficient amount of EUP was obtained from AA through chromatographic methods and identified by NMR experiment. In vivo, experimental results proved that EUP could significantly alleviate pathological features, increased SOD, GSH, and IL-10 levels, and decreased the contents of MDA, TNF-α, IL-1β, and IL-6. Further in vitro and in vivo Western blot experimental results showed that EUP significantly down-regulates the expressions of the NF-κB signal pathway to relieve inflammatory responses.

CONCLUSION

This study demonstrated that EUP could exert gastroprotective effects by inhibiting inflammation, enhancing gastric mucosal defense, and ameliorating oxidative stress, which is beneficial for providing scientific data for the development of gastric protection.

GADD45B regulates the carcinogenesis process of chronic atrophic gastritis and the metabolic pathways of gastric cancer

Background

Gastric cancer continues to be a significant global healthcare challenge, and its burden remains substantial. The development of gastric cancer (GC) is closely linked to chronic atrophic gastritis (CAG), yet there is a scarcity of research exploring the underlying mechanisms of CAG-induced carcinogenesis.

Methods

In this study, we conducted a comprehensive investigation into the oncogenes involved in CAG using both bulk transcriptome and single-cell transcriptome data. Our approach employed hdWGCNA to identify pathogenic genes specific to CAG, with non-atrophic gastritis (NAG) serving as the control group. Additionally, we compared CAG with GC, using normal gastric tissue as the control group in the single-cell transcriptome analysis. By intersecting the identified pathogenic genes, we pinpointed key network molecules through protein interaction network analysis. To further refine the gene selection, we applied LASSO, SVM-RFE, and RF techniques, which resulted in a set of cancer-related genes (CRGs) associated with CAG. To identify CRGs potentially linked to gastric cancer progression, we performed a univariate COX regression analysis on the gene set. Subsequently, we explored the relationship between CRGs and immune infiltration, drug sensitivity, and clinical characteristics in gastric cancer patients. We employed GSVA to investigate how CRGs regulated signaling pathways in gastric cancer cells, while an analysis of cell communication shed light on the impact of CRGs on signal transmission within the gastric cancer tumor microenvironment. Lastly, we analyzed changes in metabolic pathways throughout the progression of gastric cancer.

Results

Using hdWGCNA, we have identified a total of 143 pathogenic genes that were shared by CAG and GC. To further investigate the underlying mechanisms, we conducted protein interaction network analysis and employed machine learning screening techniques. As a result, we have identified 15 oncogenes that are specifically associated with chronic atrophic gastritis. By performing ROC reanalysis and prognostic analysis, we have determined that GADD45B is the most significant gene involved in the carcinogenesis of CAG. Immunohistochemical staining and differential analysis have revealed that GADD45B expression was low in GC tissues while high in normal gastric tissues. Moreover, based on prognostic analysis, high expression of GADD45B has been correlated with poor prognosis in GC patients. Additionally, an analysis of immune infiltration has shown a relationship between GADD45B and the infiltration of various immune cells. By correlating GADD45B with clinical characteristics, we have found that it primarily affects the depth of invasion in GC. Through cell communication analysis, we have discovered that the CD99 signaling pathway network and the CDH signaling pathway network are the main communication pathways that significantly alter the microenvironment of gastric tissue during the development of chronic atrophic gastritis. Specifically, GADD45B-low GC cells were predominantly involved in the network communication of the CDH signaling pathway, while GADD45B-high GC cells played a crucial role in both signaling pathways. Furthermore, we have identified several metabolic pathways, including D-Glutamine and D-glutamate metabolism and N-Glycan biosynthesis, among others, that played important roles in the occurrence and progression of GC, in addition to the six other metabolic pathways. In summary, our study highlighted the discovery of 143 pathogenic genes shared by CAG and GC, with a specific focus on 15 oncogenes associated with CAG. We have identified GADD45B as the most important gene in the carcinogenesis of CAG, which exhibited differential expression in GC tissues compared to normal gastric tissues. Moreover, GADD45B expression was correlated with patient prognosis and is associated with immune cell infiltration. Our findings also emphasized the impact of the CD99 and CDH signaling pathway networks on the microenvironment of gastric tissue during the development of CAG. Additionally, we have identified key metabolic pathways involved in GC progression.

Conclusion

GADD45B, an oncogene implicated in chronic atrophic gastritis, played a critical role in GC development. Decreased expression of GADD45B was associated with the onset of GC. Moreover, GADD45B expression levels were closely tied to poor prognosis in GC patients, influencing the infiltration patterns of various cells within the tumor microenvironment, as well as impacting the metabolic pathways involved in GC progression.

Effect of Helicobacter pylori infection and its eradication on the expression of tight junction proteins in the gastric epithelium in relation to gastric carcinogenesis

BACKGROUND

Tight junction proteins (TJPs) play a role in epithelial defense mechanisms. However, the effect of Helicobacter pylori (Hp) on TJPs remains unclear. This study aimed to evaluate the expression of TJPs in relation to Hp infection and eradication in gastric carcinogenesis.

METHODS

In total, 510 subjects (284 controls and 226 gastric cancer [GC] patients) were prospectively enrolled in the study. The expression of claudin-1 and -2 (CLDN-1, -2), occludin (OCLN), and tight junction protein 1 (TJP1) was measured based on their Hp infection status in normal corpus mucosa and evaluated following Hp eradication using quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry (IHC).

RESULTS

The expression of TJP1 in Hp⁺ controls was significantly lower than that in Hp^- controls (p = 0.006), whereas it was higher in Hp⁺ than in Hp^- GC patients (p = 0.001). Moreover, the increased expression of TJP1 in Hp⁺ GC patients was reduced to levels in Hp^- within a year after Hp eradication and was maintained for more than 5 years. Furthermore, IHC results for TJP1 were similar to qPCR results. In particular, the higher IHC staining intensity of TJP1 in the cytosol of GC patients (p = 0.019) decreased after Hp eradication (p = 0.040).

CONCLUSION

Hp infection affects TJP expression. The high expression of TJP1 in Hp⁺ GC patients was restored to control levels after Hp eradication, suggesting that TJP1 plays a role in gastric carcinogenesis.

Basic Traditional Chinese Medicinal Compound for Adjuvant Treatment of Helicobacter pylori-Related Gastritis: Implication for Anti-H. pylori-Related Gastritis Drug Discovery

This study was aimed at evaluating the efficacy of traditional Chinese medicine (TCM) in the adjuvant treatment of Helicobacter pylori-associated gastritis (HPAG) and exploring the molecular mechanism underlying the action of the basic TCM compounds against HPAG. Eight representative Chinese and British databases were combed for pertinent literature. In light of the basic principle of evidence-based medicine, this work rigorously stuck to the inclusion and exclusion of criteria so as to plump for qualified articles. Also, the data mining method was adopted to help determine the basic TCM compound for HPAG treatment. Furthermore, a network pharmacology-based strategy was used to uncover the underlying mechanisms of the basic TCM compound against HPAG. Ultimately, molecular docking was used for preliminary verification. TCM combined with triple or quadruple therapy against HPAG possessed more advantages in improving the total effective rate and H. pylori eradication rate than triple or quadruple therapy alone. The basic TCM plant materials against HPAG consisted of Citrus reticulata Blanco, Glycyrrhiza uralensis Fisch, Pinellia ternata (Thunb.) Breit, Coptis chinensis Franch, and Poria cocos (Schw.) Wolf. Quercetin, kaempferol, naringenin, baicalein, nobiletin, and hederagenin were determined as the key active ingredients of the basic TCM preparation against HPAG. Moreover, these ingredients played a therapeutic role by acting on AKT1, TP53, interleukin (IL)-6, VEGFA, CASP3, MAPK3, JUN, TNF, and MAPK8 via Pathways in cancer, PI3K-Akt signaling pathway, TNF signaling pathway, and MAPK signaling pathway. The results of molecular docking indicated that the key ingredients could bind stably with the core targets. The efficacy of the TCM in the adjuvant treatment of HPAG is worthy of affirmation. Compatible use of the key ingredients of the basic TCM compound is a novel idea of drug research with profound clinical significance and research value in the development of anti- H. pylori drugs.

Huaier attenuates the adverse effects of pyroptosis by regulating the methylation of rat mesangial cells: an in vitro study

Background

Pyroptosis is a highly programmed inflammatory cell death process that represents an innate immune response. In this study, the occurrence of pyroptosis in rat mesangial cells (RMCs) and the effect of Huaier (Trametes robiniophia Murr) on this process were investigated.

Methods

RMCs were incubated with OX7 antibodies (0.5 μg/ml, 2.5 μg/ml, 10 μg/ml), normal rat serum (NRS) and Huaier (1 mg/ml, 5 mg/ml, 10 mg/ml). RMC morphology was observed under a light microscope and by immunofluorescence. Lactate dehydrogenase (LDH) release was assessed using the CytoTox 96 Non-Radioactive Cytotoxicity Assay Kit. Western blot assays were performed, and then the RMCs were incubated with the methylase DNMT3B and the demethylase 5-aza-2′-deoxycytidine.

Results

Morphological, LDH, immunofluorescence and western blot analyses showed that RMCs were lysed when stimulated with OX7 antibodies and NRS. RMC lysis released inflammatory cytokines (interleukin-18, interleukin-1β, monocyte chemoattractant protein-1 and intracellular adhesion molecule-1), and Huaier protected RMCs by controlling lysis and the levels of inflammatory cytokines. Lysis was mediated by pyroptosis due to the positive expression of GSDME. The methylase DNMT3B reduced the expression of GSDME induced by OX7 together with NRS. Furthermore, Huaier significantly suppressed the expression of GSDME, which was increased by 5-aza-2’-deoxycytidine.

Conclusions

Pyroptosis might occur in RMCs, and Huaier can protect RMCs by upregulating the methylation of a group of molecules.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03559-4.

Ultrasonographic assessment of femoral cartilage thickness in patients with Helicobacter pylori infection

OBJECTIVES

Helicobacter pylori is a major cause of gastritis and a potential trigger of inflammatory disease. The effect of H pylori infection on distal femoral cartilage has yet to be evaluated. The aim of this study was to evaluate femoral cartilage thickness in patients with H pylori infection and to find whether this infection affects femoral cartilage thickness.

METHODS

This cross-sectional study included 199 patients. To measure the thickness of femoral articular cartilage, 99 patients with H pylori infections and 100 with H pylori-negative controls were enrolled into two groups. The measurements were made using linear probe ultrasonography with the patients in supine positions and their knees in maximum flexion. Demographic, clinical, endoscopic and laboratory data were collected for all patients.

RESULTS

Both the right and left femoral condyles had thinner cartilage thickness in the H pylori-positive group than in the H pylori-negative group (P = .016, P = .036). For the intercondylar area and lateral femoral condyles, although the H pylori-positive patients had thinner femoral cartilage thickness than the H pylori-negative individuals for both extremities, this finding was not statistically significant (P > .05).

CONCLUSION

Femoral cartilage was thinner in patients with H pylori than patients without H pylori for right and left medial femoral condyles. This study suggests that H pylori infections may affect femoral cartilage thickness and potentially increase the risk of cartilage degeneration.

The impact of ExHp-CD (outer membrane vesicles) released from Helicobacter pylori SS1 on macrophage RAW 264.7 cells and their immunogenic potential

Bacterial-derived extracellular vesicles could play a major role in attenuating and treating diseases. They play a major anti-infection role by modulating immune responses against pathogens and preventing infection by inhibiting pathogen localization and proliferation. In this study, outer membrane vesicles (ExHp-CD) released by Helicobacter pylori SS1 (H. pylori) and total antigens isolated from H. pylori SS1 (AgHp) were evaluated for their immunogenic potential and their effect on macrophage RAW 264.7 cells. Results demonstrated that both ExHp-CD and AgHp induced T helper 2 (Th2) immune response, which was reported to be important in immune protection against H. pylori infections. Both ExHp-CD and AgHp produced high levels of IL-10 and IL-4, while no significant levels of IL-12 p70 or IFN-γ were detected. However, ExHp-CD showed a better effect on macrophage RAW 264.7 cells compared to AgHp. Macrophage RAW 264.7 cells stimulated with 5, and 10 μg/mL of ExHp-CD showed an increased ratio of CD206 (M2 phenotype marker) and a decreased ratio of CD86 (M1 phenotype marker). Moreover, results suggested that the immunogenic effect that ExHp-CD possesses was attributed to their cargo of Epimerase_2 domain-containing protein (Epi_2D), Probable malate:quinone oxidoreductase (Pro_mqo), and Probable cytosol aminopeptidase (Pro_ca). Results demonstrated that ExHp-CD possesses an immunological activity to induce Th2 immune response against H. pylori infection with results comparable to AgHp. However, ExHp-CD showed higher efficacy regarding safety, biocompatibility, lack of toxicity, and hemocompatibility. Thus, it could serve as an immunogenic candidate with more desired characteristics.

Inhibitory Effect of β-Carotene on Helicobacter pylori-Induced TRAF Expression and Hyper-Proliferation in Gastric Epithelial Cells

Helicobacter pylori infection causes the hyper-proliferation of gastric epithelial cells that leads to the development of gastric cancer. Overexpression of tumor necrosis factor receptor associated factor (TRAF) is shown in gastric cancer cells. The dietary antioxidant β-carotene has been shown to counter hyper-proliferation in H. pylori-infected gastric epithelial cells. The present study was carried out to examine the β-carotene mechanism of action. We first showed that H. pylori infection decreases cellular IκBα levels while increasing cell viability, NADPH oxidase activity, reactive oxygen species production, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation, and TRAF1 and TRAF2 gene expression, as well as protein–protein interaction in gastric epithelial AGS cells. We then demonstrated that pretreatment of cells with β-carotene significantly attenuates these effects. Our findings support the proposal that β-carotene has anti-cancer activity by reducing NADPH oxidase-mediated production of ROS, NF-κB activation and NF-κB-regulated TRAF1 and TRAF2 gene expression, and hyper-proliferation in AGS cells. We suggest that the consumption of β-carotene-enriched foods could decrease the incidence of H. pylori-associated gastric disorders.

Chronic inflammation: key player and biomarker-set to predict and prevent cancer development and progression based on individualized patient profiles

A strong relationship exists between tumor and inflammation, which is the hot point in cancer research. Inflammation can promote the occurrence and development of cancer by promoting blood vessel growth, cancer cell proliferation, and tumor invasiveness, negatively regulating immune response, and changing the efficacy of certain anti-tumor drugs. It has been demonstrated that there are a large number of inflammatory factors and inflammatory cells in the tumor microenvironment, and tumor-promoting immunity and anti-tumor immunity exist simultaneously in the tumor microenvironment. The typical relationship between chronic inflammation and tumor has been presented by the relationships between Helicobacter pylori, chronic gastritis, and gastric cancer; between smoking, development of chronic pneumonia, and lung cancer; and between hepatitis virus (mainly hepatitis virus B and C), development of chronic hepatitis, and liver cancer. The prevention of chronic inflammation is a factor that can prevent cancer, so it effectively inhibits or blocks the occurrence, development, and progression of the chronic inflammation process playing important roles in the prevention of cancer. Monitoring of the causes and inflammatory factors in chronic inflammation processes is a useful way to predict cancer and assess the efficiency of cancer prevention. Chronic inflammation-based biomarkers are useful tools to predict and prevent cancer.

The effect of Helicobacter pylori infection and different H. pylori components on the proliferation and apoptosis of gastric epithelial cells and fibroblasts

Background

Helicobacter pylori colonizes the human gastric mucosa, causing chronic inflammation, peptic ulcers and gastric cancer. A cascade of harmful processes results from the interaction of these bacteria with the gastric epithelium.

Aim

To investigate these processes in terms of upregulation of oxidative stress and cell apoptosis and downregulation of the pro-regenerative activity of cells.

Methods

We employed an in vivo guinea pig model at 7 or 28 days postinoculation with H. pylori, corresponding to an acute or chronic stage of infection, respectively, and an in vitro model of guinea pig primary gastric epithelial cells and fibroblasts treated with bacterial components: glycine acid extract (GE), urease subunit A (UreA), cytotoxin-associated gene A protein (CagA) and lipopolysaccharide (LPS). Cells were evaluated for metabolic activity (MTT reduction), myeloperoxidase (MPO) and metalloproteinase (MMP-9) secretion, lipid peroxidation (4-hydroxynonenal (4HNE)), migration (wound healing), proliferation (Ki-67 antigen) and cell apoptosis (TUNEL assay; Bcl-xL, Bax, Bcl-2 expression; caspase 3 cleavage).

Results

Significant infiltration of the gastric mucosa by inflammatory cells in vivo in response to H. pylori was accompanied by oxidative stress and cell apoptosis, which were more intense 7 than 28 days after inoculation. The increase in cell proliferation was more intense in chronic than acute infection. H. pylori components GE, CagA, UreA, and LPS upregulated oxidative stress and apoptosis. Only H. pylori LPS inhibited cell migration and proliferation, which was accompanied by the upregulation of MMP-9.

Conclusions

H. pylori infection induces cell apoptosis in conjunction with increased oxidative stress. Elevated apoptosis protects against deleterious inflammation and neoplasia; however, it reduces cell integrity. Upregulation of cell migration and proliferation in response to injury in the milieu of GE, CagA or UreA facilitates tissue regeneration but increases the risk of neoplasia. By comparison, downregulation of cell regeneration by H. pylori LPS may promote chronic inflammation.

Oxyresveratrol ameliorates ethanol-induced gastric ulcer via downregulation of IL-6, TNF-α, NF-ĸB, and COX-2 levels, and upregulation of TFF-2 levels

Oxyresveratrol, an active ingredient of Artocarpus lakoocha, is known to possess anti-inflammatory and immunomodulatory properties. Current study investigates the immunomodulatory effect of oxyresveratrol in mouse model of ethanol-induced ulcer. Anti-ulcer effect was determined using histopathological evaluation (H&E staining) and different tests like, gastric ulcer scoring, ulcer index, total acid secretion, and gastric pH. The mRNA expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), nuclear factor-kappaB (NF-ĸB), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and trefoil factor 2 (TFF-2) were evaluated using reverse transcription polymerase chain reaction (RT-PCR). The data showed marked percentage inhibition of erosion, hemorrhage, fibrinoid necrosis, inflammatory infiltrate, and ulcer in low (30 mg/kg b.w.) and high dose (50 mg/kg b.w.) groups of oxyresveratrol. Treatment with oxyresveratrol inhibited ulcer score and ulcer index as compared with disease control group. Oxyresveratrol significantly increased gastric pH (P < 0.001) and attenuated total acid (P < 0.001) secretion. RT-PCR analysis showed significant suppression in the mRNA expression levels of IL-6 (P < 0.001), TNF-α (P < 0.01), NF-ĸB (P < 0.001), and COX-2 (P < 0.05) in oxyresveratrol treated groups, while COX-1 expression levels were found unaltered. Treatment with oxyresveratrol significantly elevated (P < 0.01) the expression levels of cytoprotective TFF-2 levels. Similar Immunomodulatory and anti-ulcer effects were found with ranitidine treatment, which was used as a reference drug. In conclusion, oxyresveratrol possess significant anti-ulcer property which might be attributed to attenuated expression levels of IL-6, TNF-α, NF-ĸB, and COX-2 and elevated expression levels of TFF-2.

Proteolysis in Helicobacter pylori-Induced Gastric Cancer

Persistent infections with the human pathogen and class-I carcinogen Helicobacter pylori (H. pylori) are closely associated with the development of acute and chronic gastritis, ulceration, gastric adenocarcinoma and lymphoma of the mucosa-associated lymphoid tissue (MALT) system. Disruption and depolarization of the epithelium is a hallmark of H. pylori-associated disorders and requires extensive modulation of epithelial cell surface structures. Hence, the complex network of controlled proteolysis which facilitates tissue homeostasis in healthy individuals is deregulated and crucially contributes to the induction and progression of gastric cancer through processing of extracellular matrix (ECM) proteins, cell surface receptors, membrane-bound cytokines, and lateral adhesion molecules. Here, we summarize the recent reports on mechanisms how H. pylori utilizes a variety of extracellular proteases, involving the proteases Hp0169 and high temperature requirement A (HtrA) of bacterial origin, and host matrix-metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs) and tissue inhibitors of metalloproteinases (TIMPs). H. pylori-regulated proteases represent predictive biomarkers and attractive targets for therapeutic interventions in gastric cancer.

BET Inhibition Attenuates Helicobacter pylori-Induced Inflammatory Response by Suppressing Inflammatory Gene Transcription and Enhancer Activation

Helicobacter pylori infection causes chronic gastritis and peptic ulceration. H. pylori-initiated chronic gastritis is characterized by enhanced expression of many NF-κB-regulated inflammatory cytokines. Brd4 has emerged as an important NF-κB regulator and regulates the expression of many NF-κB-dependent inflammatory genes. In this study, we demonstrated that Brd4 was not only actively involved in H. pylori-induced inflammatory gene mRNA transcription but also H. pylori-induced inflammatory gene enhancer RNA (eRNA) synthesis. Suppression of H. pylori-induced eRNA synthesis impaired H. pylori-induced mRNA synthesis. Furthermore, H. pylori stimulated NF-κB-dependent recruitment of Brd4 to the promoters and enhancers of inflammatory genes to facilitate the RNA polymerase II-mediated eRNA and mRNA synthesis. Inhibition of Brd4 by JQ1 attenuated H. pylori-induced eRNA and mRNA synthesis for a subset of NF-κB-dependent inflammatory genes. JQ1 also inhibited H. pylori-induced interaction between Brd4 and RelA and the recruitment of Brd4 and RNA polymerase II to the promoters and enhancers of inflammatory genes. Finally, we demonstrated that JQ1 suppressed inflammatory gene expression, inflammation, and cell proliferation in H. pylori-infected mice. These studies highlight the importance of Brd4 in H. pylori-induced inflammatory gene expression and suggest that Brd4 could be a potential therapeutic target for the treatment of H. pylori-triggered inflammatory diseases and cancer.