The protective effect of NF-κB signaling pathway inhibitor PDTC on mice with chronic atrophic gastritis

Yiqi Jiedu Huayu decoction inhibits precancerous lesions of chronic atrophic gastritis by inhibiting NLRP3 inflammasome-mediated pyroptosis

BACKGROUND

Chronic atrophic gastritis (CAG) is a prevalent chronic gastritis usually accompanied by precancerous lesions such as intestinal metaplasia and dysplasia. The increasing application of traditional Chinese medicine in CAG treatment has shown promising results with low side effects and significant efficacy.

AIM

To investigate the pharmacological effects of Yiqi Jiedu Huayu decoction (YJHD) on precancerous lesions of CAG.

METHODS

A CAG rat model was established by Helicobacter pylori bacteria solution combined with N-methyl-N'-nitro-N-nitrosoguanidine. Histopathological measurements were conducted by hematoxylin-eosin and alcian blue and periodic acid-Schiff staining. Serum levels of inflammatory factors and gastric mucosal-related factors were examined using enzyme-linked immunosorbent assay. Protein and mRNA levels were quantified via western blot and quantitative real-time polymerase chain reaction analysis, respectively. Molecular interaction was verified by chromatin immunoprecipitation (ChIP) assay.

RESULTS

YJHD greatly attenuated pathological changes in the gastric mucosa and precancerous lesions in CAG rats. Meanwhile, YJHD treatment reduced serum levels of inflammatory factors [interleukin (IL)-6, tumor necrosis factor-α and C-reactive protein] and increased serum levels of gastric mucosal-related factors (gastrin, pepsin, somatostatin and prostaglandin E2) in CAG rats. In addition, YJHD administration suppressed NLRP3 inflammasome-mediated cell pyroptosis, as well as the activation of TLR4/NF-κB and IL-6/STAT3 signaling pathways. Mechanically, ChIP experiments confirmed that NLRP3 transcription was regulated by TLR4/NF-κB and IL-6/STAT3 signaling.

CONCLUSION

Taken together, YJHD alleviated NLRP3 inflammasome formation and pyroptosis of epithelial cells in CAG, potentially through the inactivation of TLR4/NF-κB and IL-6/STAT3 pathways.

Research on drug treatment and the novel signaling pathway of chronic atrophic gastritis

BACKGROUND

Chronic atrophic gastritis (CAG) is a global digestive system disease and one of the important causes of gastric cancer. The incidence of CAG has been increasing yearly worldwide.

PURPOSE

This article reviews the latest research on the common causes and future therapeutic targets of CAG as well as the pharmacological effects of corresponding clinical drugs. We provide a detailed theoretical basis for further research on possible methods for the treatment of CAG and reversal of the CAG process.

RESULTS

CAG often develops from chronic gastritis, and its main pathological manifestation is atrophy of the gastric mucosa, which can develop into gastric cancer. The drug treatment of CAG can be divided into agents that regulate gastric acid secretion, eradicate Helicobacter. pylori (H. pylori), protect gastric mucous membrane, or inhibit inflammatory factors according to their mechanism of action. Although there are limited specific drugs for the treatment of CAG, progress is being made in defining the pathogenesis and therapeutic targets of the disease. Growing evidence shows that NF-κB, PI3K/AKT, Wnt/ β-catenin, MAPK, Toll-like receptors (TLRs), Hedgehog, and VEGF signaling pathways play an important role in the development of CAG.

Geniposide ameliorates brain injury in mice with intracerebral hemorrhage by inhibiting NF-κB signaling

BACKGROUND

Neuroinflammation and oxidative stress are critical players in intracerebral hemorrhage (ICH). Geniposide is an active component of Gardenia that has anti-inflammatory effects. This study focused on the roles and mechanisms of geniposide in ICH.

METHODS

ICH was established by injecting collagenase IV into C57BL/6 mice. To determine the functions of geniposide and NF-κB inhibition in ICH model mice, geniposide (1, 25, or 50 mg/kg) or PDTC (a NF-κB inhibitor) was administered. Neurological functions were assessed with the modified neurological severity score (mNSS) test. Hematoxylin and eosin staining were performed to identify pathological changes. IL-1β and TNF-α levels were estimated with ELISA kits. NF-κB p65 localization was determined by immunofluorescence staining. Oxidative stress was analyzed by measuring ROS levels.

RESULTS

Geniposide alleviated cerebral edema and neurological deficits. Geniposide inhibited neuroinflammation and oxidative stress after ICH, and the inhibitory effects were enhanced by NF-κB inhibition. Additionally, geniposide inhibited NF-κB signaling.

CONCLUSION

Geniposide alleviates brain injury by suppressing inflammation and oxidative stress damage in experimental ICH models by inhibiting NF-κB signaling.

Serum Induces the Subunit-Specific Activation of NF-κB in Proliferating Human Cardiac Stem Cells

Cardiovascular diseases (CVDs) are often linked to ageing and are the major cause of death worldwide. The declined proliferation of adult stem cells in the heart often impedes its regenerative potential. Thus, an investigation of the proliferative potential of adult human cardiac stem cells (hCSCs) might be of great interest for improving cell-based treatments of cardiovascular diseases. The application of human blood serum was already shown to enhance hCSC proliferation and reduce senescence. Here, the underlying signalling pathways of serum-mediated hCSC proliferation were studied. We are the first to demonstrate the involvement of the transcription factor NF-κB in the serum-mediated proliferative response of hCSCs by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). RNA-Sequencing (RNA-Seq) revealed ATF6B, COX5B, and TNFRSF14 as potential targets of NF-κB that are involved in serum-induced hCSC proliferation.

Role of dendritic cells in MYD88-mediated immune recognition and osteoinduction initiated by the implantation of biomaterials

Bone substitute material implantation has become an important treatment strategy for the repair of oral and maxillofacial bone defects. Recent studies have shown that appropriate inflammatory and immune cells are essential factors in the process of osteoinduction of bone substitute materials. Previous studies have mainly focused on innate immune cells such as macrophages. In our previous work, we found that T lymphocytes, as adaptive immune cells, are also essential in the osteoinduction procedure. As the most important antigen-presenting cell, whether dendritic cells (DCs) can recognize non-antigen biomaterials and participate in osteoinduction was still unclear. In this study, we found that surgical trauma associated with materials implantation induces necrocytosis, and this causes the release of high mobility group protein-1 (HMGB1), which is adsorbed on the surface of bone substitute materials. Subsequently, HMGB1-adsorbed materials were recognized by the TLR4-MYD88-NFκB signal axis of dendritic cells, and the inflammatory response was activated. Finally, activated DCs release regeneration-related chemokines, recruit mesenchymal stem cells, and initiate the osteoinduction process. This study sheds light on the immune-regeneration process after bone substitute materials implantation, points out a potential direction for the development of bone substitute materials, and provides guidance for the development of clinical surgical methods.

Elian granules alleviate precancerous lesions of gastric cancer in rats by suppressing M2-type polarization of tumor-associated macrophages through NF-κB signaling pathway

BACKGROUND

Precancerous lesions of gastric cancer (PLGC) refer to a kind of histopathological changes in the gastric mucosa that can progress to gastric cancer. Elian granules (ELG), a Chinese medicinal prescription, have achieved satisfactory results in the treatment of PLGC. However, the exact mechanism underlying the therapeutic effect of ELG remains unclear. Here, this study aims to explore the mechanism of ELG alleviating PLGC in rats.

METHODS

The chemical ingredients of ELG were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS). Specific Pathogen Free SD rats were randomly assigned to 3 groups: the control, model, and ELG groups. The 1-Methyl-3-nitro-1-nitrosoguanidine (MNNG) integrated modeling method was adopted to construct the PLGC rat model in groups except for the control group. Meanwhile, normal saline was used as an intervention for the control and model groups, and ELG aqueous solution for the ELG group, lasting 40 weeks. Subsequently, the stomach of rats was harvested for further analysis. Hematoxylin-eosin staining of the gastric tissue was conducted to assess the pathological changes. Immunofluorescence was carried out for the expression of CD68, and CD206 proteins. Real-time quantitative PCR combined with Western blot was conducted to analyze the expression of arginase-1(Arg-1), inducible nitric oxide synthase (iNOS), p65, p-p65, nuclear factor inhibitor protein-α (IκBα), and p-IκBα in gastric antrum tissue.

RESULTS

Five chemical ingredients including Curcumol, Curzerenone, Berberine, Ferulic Acid, and 2-Hydroxy-3-Methylanthraquine were identified in ELG. The gastric mucosal glands of rats treated with ELG were orderly arranged, with no intestinal metaplasia and no dysplasia. Furthermore, ELG decreased the percentage of M2-type TAMs marked with CD68 and CD206 proteins, and the ratio of Arg-1 to iNOS in the gastric antrum tissue of rats with PLGC. In addition, ELG could also down-regulate the protein and mRNA expression of p-p65, p65, and p-IκBα, but up-regulate the expression of IκBα mRNA in rats with PLGC.

CONCLUSIONS

The results showed that ELG attenuates PLGC in rats by suppressing the M2-type polarization of tumor-associated macrophages (TAMs) through NF-κB signaling pathway.

AFG1-induced TNF-α-mediated inflammation enhances gastric epithelial cell injury via CYP2E1

Aflatoxin G₁ (AFG₁), a member of the aflatoxin family with cytotoxic and carcinogenic properties, is one of the most common mycotoxins occurring in various agricultural products, animal feed, and human foods and drinks worldwide. Epithelial cells in the gastrointestinal tract are the first line of defense against ingested mycotoxins. However, the toxicity of AFG₁ to gastric epithelial cells (GECs) remains unclear. In this study, we explored whether and how AFG₁-induced gastric inflammation regulates cytochrome P450 to contribute to DNA damage in GECs. Oral administration of AFG₁ induced gastric inflammation and DNA damage in mouse GECs associated with P450 2E1 (CYP2E1) upregulation. Treatment with the soluble TNF-α receptor sTNFR:Fc inhibited AFG₁-induced gastric inflammation, and reversed CYP2E1 upregulation and DNA damage in mouse GECs. TNF-α-mediated inflammation plays an important role in AFG₁-induced gastric cell damage. Using the human gastric cell line GES-1, AFG₁ upregulated CYP2E1 through NF-κB, causing oxidative DNA damage in vitro. The cells were also treated with TNF-α and AFG₁ to mimic AFG₁-induced TNF-α-mediated inflammation. TNF-α activated the NF-κB/CYP2E1 pathway to promote AFG₁ activation, which enhanced DNA cellular damage in vitro. In conclusion, AFG₁ ingestion induces TNF-α-mediated gastric inflammation, which upregulates CYP2E1 to promote AFG₁-induced DNA damage in GECs.

Effects of Granule Dendrobii on chronic atrophic gastritis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats

BACKGROUND

Dendrobium officinale is an herb of Traditional Chinese Medicine (TCM) commonly used for treating stomach diseases. One formula of Granule Dendrobii (GD) consists of Dendrobium officinale and American Ginseng (Radix Panacis quinquefolii), and is a potent TCM product in China. Whether treatment with GD can promote gastric acid secretion and alleviate gastric gland atrophy in chronic atrophic gastritis (CAG) requires verification.

AIM

To determine the effect of GD treatment on CAG and its potential cellular mechanism.

METHODS

A CAG model was induced by feeding rats N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for 12 wk. After oral administration of low, moderate, and high doses of GD in CAG rats for 8 wk, its effects on body weight, gastric mucosa histology, mucosal atrophy, intestinal metaplasia, immunohistochemical staining of proliferating cell nuclear antigen (PCNA) and B-cell lymphoma-2, and hemoglobin and red blood cells were examined.

RESULTS

The body weights of MNNG-induced CAG model rats before treatment (143.5 ± 14.26 g) were significantly lower than that of healthy rats (220.2 ± 31.20 g, P < 0.01). At the 8^th week of treatment, the body weights of rats in the low-, moderate-, and high-dose groups of GD (220.1 ± 36.62 g) were significantly higher than those in the untreated group (173.3 ± 28.09 g, all P < 0.01). The level of inflammation in gastric tissue of the high-dose group (1.68 ± 0.54) was significantly reduced (P < 0.01) compared with that of the untreated group (3.00 ± 0.00, P < 0.05). The number and thickness of gastric glands in the high-dose group (31.50 ± 6.07/mm, 306.4 ± 49.32 µm) were significantly higher than those in the untreated group (26.86 ± 6.41/mm, 244.3 ± 51.82 µm, respectively, P < 0.01 and P < 0.05), indicating improved atrophy of gastric mucosa. The areas of intestinal metaplasia were significantly lower in the high-dose group (1.74% ± 1.13%), medium-dose group (1.81% ± 0.66%) and low-dose group (2.36% ± 1.08%) than in the untreated group (3.91% ± 0.96%, all P < 0.01). The expression of PCNA in high-dose group was significantly reduced compared with that in untreated group (P < 0.01). Hemoglobin level in the high-dose group (145.3 ± 5.90 g/L), medium-dose group (139.3 ± 5.71 g/L) and low-dose group (137.5 ± 7.56 g/L) was markedly increased compared with the untreated group (132.1 ± 7.76 g/L; P < 0.01 or P < 0.05).

CONCLUSION

Treatment with GD for 8 wk demonstrate that GD is effective in the treatment of CAG in the MNNG model by improving the histopathology of gastric mucosa, reversing gastric atrophy and intestinal metaplasia, and alleviating gastric inflammation.

Regularity of Toll-Like Receptors in Bovine Mammary Epithelial Cells Induced by Mycoplasma bovis

Mastitis is one of the most common and significant infectious diseases in dairy cattle and is responsible for significant financial losses for the dairy industry globally. An important pathogen of bovine mastitis, Mycoplasma bovis (M. bovis) has a high infection rate, requires a long course of treatment, and is difficult to cure. Bovine mammary epithelial cells (BMECs) are the first line of defense of the mammary gland, and their natural immune system plays a critical role in resisting M. bovis infection. This study aimed to explore and demonstrate the regularity of Toll-like receptors (TLRs) activation during M. bovis infection and their function during M. bovis mastitis. An in vitro model of M. bovis-induced mastitis showed that the expression of IL-6, IL-8, and TNF-α increased significantly following infection. M. bovis infection also upregulated the expression of TLR1/2/6 on the cell membrane and TLR3/9 in the cytoplasm. There is a crosstalk effect between TLR1–TLR2 and TLR2–TLR6. Furthermore, M. bovis infection was found to activate the TLR1/2/6/9/MyD88/NF-κB and TLR3/TRIF/IRF signal transduction pathways, which in turn activate inflammatory factors. These findings lay the theoretical foundation for understanding the pathogenesis of M. bovis, permitting the development of effective measures for preventing and controlling M. bovis mastitis.

Matrix Metalloproteinases in Helicobacter pylori-Associated Gastritis and Gastric Cancer

Gastric cancer is one of the leading causes of the cancer-related mortality worldwide. The etiology of this disease is complex and involves genetic predisposition and environmental factors, including Helicobacter pylori. Infection of the stomach with H. pylori leads to gastritis and gastric atrophy, which can progress stepwise to gastric cancer. Matrix metalloproteinases (MMPs) actively participate in the pathology development. The further progression of gastric cancer seems to be less dependent on bacteria but of intra-tumor cell dynamics. Bioinformatics data confirmed an important role of the extracellular matrix constituents and specific MMPs in stomach carcinoma invasion and metastasis, and revised their potential as predictors of the disease outcome. In this review, we describe, in detail, the impact of MMPs in H. pylori-associated gastritis and gastric cancer.