IL-17A promotes Helicobacter pylori-induced gastric carcinogenesis via interactions with IL-17RC

Gastric digestion of the sweet-tasting plant protein thaumatin releases bitter peptides that reduce H. pylori induced pro-inflammatory IL-17A release via the TAS2R16 bitter taste receptor

About half of the world's population is infected with the bacterium Helicobacter pylori. For colonization, the bacterium neutralizes the low gastric pH and recruits immune cells to the stomach. The immune cells secrete cytokines, i.e., the pro-inflammatory IL-17A, which directly or indirectly damage surface epithelial cells. Since (I) dietary proteins are known to be digested into bitter tasting peptides in the gastric lumen, and (II) bitter tasting compounds have been demonstrated to reduce the release of pro-inflammatory cytokines through functional involvement of bitter taste receptors (TAS2Rs), we hypothesized that the sweet-tasting plant protein thaumatin would be cleaved into anti-inflammatory bitter peptides during gastric digestion. Using immortalized human parietal cells (HGT-1 cells), we demonstrated a bitter taste receptor TAS2R16-dependent reduction of a H. pylori-evoked IL-17A release by up to 89.7 ± 21.9% (p ≤ 0.01). Functional involvement of TAS2R16 was demonstrated by the study of specific antagonists and siRNA knock-down experiments.

IL-17RA-Mediated Epithelial Cell Activity Prevents Severe Inflammatory Response to Helicobacter pylori Infection

Helicobacter pylori is a Gram-negative pathogen that colonizes the stomach, induces inflammation, and drives pathological changes in the stomach tissue, including gastric cancer. As the principal cytokine produced by Th17 cells, IL-17 mediates protective immunity against pathogens by inducing the activation and mobilization of neutrophils. Whereas IL-17A is largely produced by lymphocytes, the IL-17 receptor is expressed in epithelial cells, fibroblasts, and hematopoietic cells. Loss of the IL-17RA in mice results in impaired antimicrobial responses to extracellular bacteria. In the context of H. pylori infection, this is compounded by extensive inflammation in Il17ra-/- mice. In this study, Foxa3creIl17rafl/fl (Il17raΔGI-Epi) and Il17rafl/fl (control) mice were used to test the hypothesis that IL-17RA signaling, specifically in epithelial cells, protects against severe inflammation after H. pylori infection. The data indicate that Il17raΔGI-Epi mice develop increased inflammation compared with controls. Despite reduced Pigr expression, levels of IgA increased in the gastric wash, suggesting significant increase in Ag-specific activation of the T follicular helper/B cell axis. Gene expression analysis of stomach tissues indicate that both acute and chronic responses are significantly increased in Il17raΔGI-Epi mice compared with controls. These data suggest that a deficiency of IL-17RA in epithelial cells is sufficient to drive chronic inflammation and hyperactivation of the Th17/T follicular helper/B cell axis but is not required for recruitment of polymorphonuclear neutrophils. Furthermore, the data suggest that fibroblasts can produce chemokines in response to IL-17 and may contribute to H. pylori-induced inflammation through this pathway.

Interleukin-17 alleviates erastin-induced alveolar bone loss by suppressing ferroptosis via interaction between NRF2 and p-STAT3

AIM

To investigate the relationship between interleukin-17 (IL-17), ferroptosis and osteogenic differentiation.

MATERIALS AND METHODS

We first analysed the changes in ferroptosis-related molecules in experimental periodontitis models. The effects of erastin, a small-molecule ferroptosis inducer, and IL-17 on alveolar bone loss and repair in animal models were then investigated. Primary mouse mandibular osteoblasts were exposed to erastin and IL-17 in vitro. Ferroptosis- and osteogenesis-related genes and proteins were detected. Further, siRNA, immunofluorescence co-localization and immunoprecipitation were used to confirm the roles of the nuclear factor erythroid-2-related factor 2 (NRF2) and phosphorylated signal transducer and activator of transcription 3 (p-STAT3), as well as their interaction.

RESULTS

The levels of NRF2, glutathione peroxidase 4 and solute carrier family 7 member 11 were lower in the ligated tissues than in normal periodontal tissues. Alveolar bone loss in an in vivo experimental periodontitis model was aggravated by erastin and alleviated by IL-17. In vitro, IL-17 ameliorated erastin-inhibited osteogenic differentiation by reversing ferroptosis. Altered NRF2 expression correlated with changes in ferroptosis-related molecules and osteogenesis. Furthermore, the physical interaction between NRF2 and p-STAT3 was confirmed in the nucleus. In IL-17 + erastin-stimulated osteoblasts, the p-STAT3-NRF2 complex might actively participate in the downstream transcription of ferroptosis- and osteogenesis-related genes.

CONCLUSIONS

IL-17 administration conferred resistance to erastin-induced osteoblast ferroptosis and osteogenesis. The possible mechanism may involve p-STAT3 directly interacting with NRF2.

IL-17A promotes tumorigenesis and upregulates PD-L1 expression in non-small cell lung cancer

BACKGROUND

The tumor microenvironment plays a key role in non-small cell lung cancer (NSCLC) development and also influences the effective response to immunotherapy. The pro-inflammatory factor interleukin-17A mediates important immune responses in the tumor microenvironment. In this study, the potential role and mechanisms of IL-17A in NSCLC were investigated.

METHODS

We detected IL-17A by immunohistochemistry (IHC) in 39 NSCLC patients. Its expression was correlated with the programmed cell death-ligand1 (PD-L1). IL-17A knockdown and overexpression in A549 and SPC-A-1 cell models were constructed. The function of IL-17A was examined in vitro by wound healing, migration, invasion, plate colony formation and T cell killing assay. Western blot analysis, immunofluorescence assay and IHC were performed to investigate the regulation effects of IL-17A on autophagy in A549 and SPC-A-1. The effect of IL-17A on ROS/Nrf2/p62 signaling pathway was detected. Subcutaneous tumor models were established to examine the tumor-promoting effect of IL-17A in vivo and its effect on immunotherapy.

RESULTS

We found a prevalent expression of IL-17A in NSCLC tumor tissues and it was positively correlated with PD-L1 expression (r = 0.6121, p < 0.0001). In vitro, IL-17A promotes lung cancer cell migration, invasion and colony formation ability. Moreover, IL-17A upregulated N-cadherin, Twist, and Snail, and downregulated E-cadherin in NSCLC cells. IL-17A enhanced cell survival in the T cell killing assay. Mechanistically, IL-17A induced ROS production and increased Nrf2 and p62 expression, thereby inhibiting autophagy and reducing PD-L1 degradation. In vivo experiments, anti-IL-17A monoclonal antibody alone slowed the growth of subcutaneous tumors in mice. When combined with anti-PD-L1 monoclonal antibody, tumor tissue expression of PD-L1 was reduced and the therapeutic effect was diminished.

CONCLUSION

We found that IL-17A promoted NSCLC progression and inhibited autophagy through the ROS/Nrf2/p62 pathway leading to increased PD-L1 expression in cancer cells. Modulation of IL-17A may affect the therapeutic efficacy of immunotherapy.

Serum cytokines and neutrophil-to-lymphocyte ratio as predictive biomarkers of benefit from PD-1 inhibitors in gastric cancer

Background

Immunotherapy is significantly revolutionizing cancer treatment and demonstrating promising efficacy in gastric cancer (GC) patients. However, only a subset of patients could derive benefits from targeted monoclonal antibody therapy against programmed death receptor 1 (PD-1). This study aims to identify suitable serum cytokines and blood cell ratios as predictive biomarkers to aid in the selection of GC patients likely to benefit from PD-1 inhibitors.

Materials and methods

This retrospective study included 41 GC patients who received PD-1 inhibitors combined with chemotherapy, 36 GC patients treated solely with chemotherapy, and 33 healthy controls. The study assessed the levels of seven cytokines: interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17A, tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), and various inflammatory markers, including the neutrophil-to-lymphocyte ratio (NLR), total lymphocyte count (TLC), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR). Measurements were obtained using the inpatient system. Univariate and multivariate Cox regression analyses were performed to evaluate the predictive significance of these hematologic parameters for clinical outcomes.

Results

Levels of IL-6, IL-10, TNF-α, NLR, and PLR were significantly elevated in GC patients compared to healthy controls, while TLC and LMR were higher in the control group. Among the 41 patients receiving PD-1 inhibitors and chemotherapy, baseline IL-2 was associated with OS and PFS. Additionally, IL-6 and IL-17A correlated with OS, while NLR was linked to PFS (all P<0.05). These factors were identified as independent prognostic indicators in both univariate and multivariate analyses. Furthermore, almost all cytokine levels increased following the initiation of PD-1 inhibitor treatment.

Conclusions

The introduction of PD-1 inhibitors alongside chemotherapy in GC impacts serum cytokine levels. IL-2, IL-6, IL-17A, and NLR exhibit potential as reliable circulating predictive biomarkers for identifying patients who may benefit from PD-1 inhibitors combined with chemotherapy.

IL-17A functions and the therapeutic use of IL-17A and IL-17RA targeted antibodies for cancer treatment

Interleukin 17A (IL-17A) is a major member of the IL-17 cytokine family and is produced mainly by T helper 17 (Th17) cells. Other cells such as CD8+ T cells, γδ T cells, natural killer T cells and innate lymphoid-like cells can also produce IL-17A. In healthy individuals, IL-17A has a host-protective capacity, but excessive elevation of IL-17A is associated with the development of autoimmune diseases and cancer. Monoclonal antibodies (mAbs) targeting IL-17A (e.g., ixekizumab and secukinumab) or IL-17A receptor (IL-17RA) (e.g., brodalumab) would be investigated as potential treatments for these diseases. Currently, the application of IL-17A-targeted drugs in autoimmune diseases will provide new ideas for the treatment of tumors, and its combined application with immune checkpoint inhibitors has become a research hotspot. This article reviews the mechanism of action of IL-17A and the application of anti-IL-17A antibodies, focusing on the research progress on the mechanism of action and therapeutic blockade of IL-17A in various tumors such as colorectal cancer (CRC), lung cancer, gastric cancer and breast cancer. Moreover, we also include the results of therapeutic blockade in the field of cancer as well as recent advances in the regulation of IL-17A signaling.

A study related to the treatment of gastric cancer with Xiang-Sha-Liu-Jun-Zi-Tang based on network analysis

Purpose

Xiang-Sha-Liu-Jun-Zi-Tang(XSLJZT) is a common formula for the treatment of Gastric Cancer(GC) and is widely used in clinical practice, however, there is a lack of investigation into its mechanism.

Methods

We collected and organized drug and disease targets, constructed the "XSLJZT-Active Ingredient-Target" visualization network, and performed GO and KEGG functional enrichment analysis of crossover genes, followed by molecular docking of active ingredients and core targets. The best docked monomers were combined with weighted gene co-expression network analysis(WGCNA) and macroscopically analyzed by GO and KEGG enrichment techniques. The results of cluster gene difference analysis, ROC evaluation, and CIBERSORT immune infiltration analysis were evaluated and finally supported by cellular experiments.

Results

The main components of XSLJZT are quercetin, stigmasterol, and naringenin, effectively treat GC by targeting STAT3, TP53 and MAPK3, which are involved in IL-17, TNF and HIF-1 signaling pathways. The results of molecular docking showed that quercetin bound better to the core targets. We performed an in-depth analysis of this monomer and found that quercetin acts on the core targets of TP53, MMP9, TIMP1 and MYC, and is involved in two key signaling pathways, TNF and IL-17, thus effectively treating GC. The experimental results are consistent with our analysis that quercetin inhibits the proliferation of GC cells and promotes apoptosis, and TP53, MYC and TIMP1 are the quercetin targets for the treatment of GC.

Conclusion

The present study tentatively suggests that quercetin, the main active ingredient in XSLJZT, can exert a therapeutic effect on GC by targeting TIMP1.

Identification and verification of ferroptosis-related genes in gastric intestinal metaplasia

Background: Gastric intestinal metaplasia (IM) is the key link of gastric precancerous lesions. Ferroptosis is a novel form of programmed cell death. However, its impact on IM is unclear. The focus of this study is to identify and verify ferroptosis-related genes (FRGs) that may be involved in IM by bioinformatics analysis. Materials and methods: Differentially expressed genes (DEGs) were obtained from microarray dataset GSE60427 and GSE78523 downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed ferroptosis-related genes (DEFRGs) were obtained from overlapping genes of DEGs and FRGs got from FerrDb. DAVID database was used for functional enrichment analysis. Protein-protein interaction (PPI) analysis and Cytoscape software were used to screen hub gene. In addition, we built a receiver operating characteristic (ROC) curve and verified the relative mRNA expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, the CIBERSORT algorithm was used to analyze the immune infiltration in IM. Results: First, a total of 17 DEFRGs were identified. Second, a gene module identified by Cytoscape software was considered as hub gene: PTGS2, HMOX1, IFNG, and NOS2. Third, ROC analysis showed that HMOX1 and NOS2 had good diagnostic characteristics. qRT-PCR experiments confirmed the differential expression of HMOX1 in IM and normal gastric tissues. Finally, immunoassay showed that the proportion of T cells regulatory (Tregs) and macrophages M0 in IM was relatively higher, while the proportion of T cells CD4 memory activated and dendritic cells activated was lower. Conclusion: We found significant associations between FRGs and IM, and HMOX1 may be diagnostic biomarkers and therapeutic targets for IM. These results may enhance our understanding of IM and may contribute to its treatment.

Immune Biology and Persistence of Helicobacter pylori in Gastric Diseases

Helicobacter pylori is a prevalent pathogen, which affects more than 40% of the global population. It colonizes the human stomach and persists in its host for several decades or even a lifetime, if left untreated. The persistent infection has been linked to various gastric diseases, including gastritis, peptic ulcers, and an increased risk for gastric cancer. H. pylori infection triggers a strong immune response directed against the bacterium associated with the infiltration of innate phagocytotic immune cells and the induction of a Th1/Th17 response. Even though certain immune cells seem to be capable of controlling the infection, the host is unable to eliminate the bacteria as H. pylori has developed remarkable immune evasion strategies. The bacterium avoids its killing through innate recognition mechanisms and manipulates gastric epithelial cells and immune cells to support its persistence. This chapter focuses on the innate and adaptive immune response induced by H. pylori infection, and immune evasion strategies employed by the bacterium to enable persistent infection.