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Glucocorticoids are steroid hormones well-known for their potent anti-inflammatory effects. However, their immunomodulatory properties are multifaceted. Increasing evidence suggests that glucocorticoid signaling promotes effective immunity and that disruption of glucocorticoid signaling impairs immune function. In this study, we conditionally deleted the glucocorticoid receptor (GR) in the myeloid lineage using the LysM-Cre driver (myGRKO). We examined the impact on macrophage activation and gastric immune responses to Helicobacter pylori, the best-known risk factor of gastric cancer. Our results indicate that, compared to WT, GRKO macrophages exhibited higher expression of proinflammatory genes in steroid-free conditions. However, when challenged in vivo, GRKO macrophages exhibited aberrant chromatin landscapes and impaired proinflammatory gene expression profiles. Moreover, gastric colonization with Helicobacter pylori revealed impaired gastric immune responses and reduced T cell recruitment in myGRKO mice. As a result, myGRKO mice were protected from atrophic gastritis and pyloric metaplasia development. These results demonstrate a dual role for glucocorticoid signaling in preparing macrophages to respond to bacterial infection but limiting their pathogenic activation. In addition, our results support that macrophages are critical for gastric Helicobacter pylori immunity.
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Emerging evidence in preclinical models demonstrates that antitumor immunity is not equivalent between males and females. However, more investigation in patients and across a wider range of cancer types is needed to fully understand sex as a variable in tumor immune responses. We investigated differences in T-cell responses between male and female patients with lung cancer by performing sex-based analysis of single cell transcriptomic datasets. We found that the transcript encoding CXC motif chemokine ligand 13 (CXCL13), which has recently been shown to correlate with T-cell tumor specificity, is expressed at greater levels in T cells isolated from female compared with male patients. Furthermore, increased CXCL13 expression was associated with response to PD1-targeting immunotherapy in female but not male patients. These findings suggest that there are sex-based differences in T-cell function required for response to anti-PD1 therapy in lung cancer that may need to be considered during patient treatment decisions. See related Spotlight by Cruz-Hinojoza and Stromnes, p. 952.
Sujet(s)
Chimiokine CXCL13 , Immunothérapie , Tumeurs du poumon , Lymphocytes T , Humains , Chimiokine CXCL13/métabolisme , Tumeurs du poumon/immunologie , Tumeurs du poumon/thérapie , Tumeurs du poumon/traitement médicamenteux , Femelle , Mâle , Immunothérapie/méthodes , Lymphocytes T/immunologie , Lymphocytes T/métabolisme , Facteurs sexuels , Régulation de l'expression des gènes tumoraux , Inhibiteurs de points de contrôle immunitaires/usage thérapeutique , Inhibiteurs de points de contrôle immunitaires/pharmacologie , Récepteur-1 de mort cellulaire programmée/antagonistes et inhibiteurs , Récepteur-1 de mort cellulaire programmée/métabolismeRÉSUMÉ
Obesity is a well-established risk factor for human cancer, yet the underlying mechanisms remain elusive. Immune dysfunction is commonly associated with obesity but whether compromised immune surveillance contributes to cancer susceptibility in individuals with obesity is unclear. Here we use a mouse model of diet-induced obesity to investigate tumor-infiltrating CD8 + T cell responses in lean, obese, and previously obese hosts that lost weight through either dietary restriction or treatment with semaglutide. While both strategies reduce body mass, only dietary intervention restores T cell function and improves responses to immunotherapy. In mice exposed to a chemical carcinogen, obesity-related immune dysfunction leads to higher incidence of sarcoma development. However, impaired immunoediting in the obese environment enhances tumor immunogenicity, making the malignancies highly sensitive to immunotherapy. These findings offer insight into the complex interplay between obesity, immunity and cancer, and provide explanation for the obesity paradox observed in clinical immunotherapy settings.
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Tumeurs , Obésité , Humains , Animaux , Souris , Monitorage immunologique , Obésité/étiologie , Régime alimentaire , Facteurs de risqueRÉSUMÉ
Head and neck cancer (HNC) is prevalent worldwide, and treatment options are limited. Momordicine-I (M-I), a natural component from bitter melon, shows antitumor activity against these cancers, but its mechanism of action, especially in the tumor microenvironment (TME), remains unclear. In this study, we establish that M-I reduces HNC tumor growth in two different immunocompetent mouse models using MOC2 and SCC VII cells. We demonstrate that the anticancer activity results from modulating several molecules in the monocyte/macrophage clusters in CD45+ populations in MOC2 tumors by single-cell RNA sequencing. Tumor-associated macrophages (TAM) often pose a barrier to antitumor effects, but following M-I treatment, we observe a significant reduction in the expression of Sfln4, a myeloid cell differentiation factor, and Cxcl3, a neutrophil chemoattractant, in the monocyte/macrophage populations. We further find that the macrophages must be in close contact with the tumor cells to inhibit Sfln4 and Cxcl3, suggesting that these TAMs are impacted by M-I treatment. Coculturing macrophages with tumor cells shows inhibition of Agr1 expression following M-I treatment, which is indicative of switching from M2 to M1 phenotype. Furthermore, the total B-cell population in M-I-treated tumors is significantly lower, whereas spleen cells also show similar results when cocultured with MOC2 cells. M-I treatment also inhibits PD1, PD-L1, and FoxP3 expression in tumors. Collectively, these results uncover the potential mechanism of M-I by modulating immune cells, and this new insight can help to develop M-I as a promising candidate to treat HNCs, either alone or as adjuvant therapy.
Sujet(s)
Lymphocytes B , Tumeurs de la tête et du cou , Animaux , Souris , Tumeurs de la tête et du cou/traitement médicamenteux , Tumeurs de la tête et du cou/anatomopathologie , Tumeurs de la tête et du cou/immunologie , Humains , Lymphocytes B/effets des médicaments et des substances chimiques , Lymphocytes B/immunologie , Lymphocytes B/métabolisme , Lymphocytes TIL/immunologie , Lymphocytes TIL/effets des médicaments et des substances chimiques , Lymphocytes TIL/métabolisme , Macrophages associés aux tumeurs/effets des médicaments et des substances chimiques , Macrophages associés aux tumeurs/immunologie , Macrophages associés aux tumeurs/métabolisme , Microenvironnement tumoral/effets des médicaments et des substances chimiques , Macrophages/effets des médicaments et des substances chimiques , Macrophages/métabolisme , Macrophages/immunologie , Lignée cellulaire tumorale , Prolifération cellulaire/effets des médicaments et des substances chimiquesRÉSUMÉ
BACKGROUND & AIMS: Acute and chronic gastric injury induces alterations in differentiation within the corpus of the stomach called pyloric metaplasia. Pyloric metaplasia is characterized by the death of parietal cells and reprogramming of mitotically quiescent zymogenic chief cells into proliferative, mucin-rich spasmolytic polypeptide-expressing metaplasia (SPEM) cells. Overall, pyloric metaplastic units show increased proliferation and specific expansion of mucous lineages, both by proliferation of normal mucous neck cells and recruitment of SPEM cells. Here, we identify Sox9 as a potential gene of interest in the regulation of mucous neck and SPEM cell identity in the stomach. METHODS: We used immunostaining and electron microscopy to characterize the expression pattern of SRY-box transcription factor 9 (SOX9) during murine gastric development, homeostasis, and injury in homeostasis, after genetic deletion of Sox9 and after targeted genetic misexpression of Sox9 in the gastric epithelium and chief cells. RESULTS: SOX9 is expressed in all early gastric progenitors and strongly expressed in mature mucous neck cells with minor expression in the other principal gastric lineages during adult homeostasis. After injury, strong SOX9 expression was induced in the neck and base of corpus units in SPEM cells. Adult corpus units derived from Sox9-deficient gastric progenitors lacked normal mucous neck cells. Misexpression of Sox9 during postnatal development and adult homeostasis expanded mucous gene expression throughout corpus units including within the chief cell zone in the base. Sox9 deletion specifically in chief cells blunts their reprogramming into SPEM. CONCLUSIONS: Sox9 is a master regulator of mucous neck cell differentiation during gastric development. Sox9 also is required for chief cells to fully reprogram into SPEM after injury.
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Cellules principales de l'estomac , Animaux , Souris , Cellules principales de l'estomac/métabolisme , Muqueuse gastrique/métabolisme , Métaplasie/métabolisme , Cellules pariétales gastriques/métabolisme , EstomacRÉSUMÉ
Checkpoint blockade immunotherapy has become a first-line treatment option for cancer patients, with success in increasingly diverse cancer types. Still, many patients do not experience durable responses and the reasons for clinical success versus failure remain largely undefined. Investigation of immune responses within the tumor microenvironment can be highly informative but access to tumor tissue is not always available, highlighting the need to identify biomarkers in the blood that correlate with clinical success. Here, we used single-cell RNA sequencing coupled with T cell receptor sequencing to define CD8+ T cell responses in peripheral blood of two patients with melanoma before and after immunotherapy with either anti-PD-1 (nivolumab) alone or the combination of anti-PD-1 and CTLA-4 (ipilimumab). Both treatment regimens increased transcripts associated with cytolytic effector function and decreased transcripts associated with naive T cells. These responses were further evaluated at the protein level and extended to a total of 53 patients with various cancer types. Unexpectedly, the induction of CD8+ T cell responses associated with cytolytic function was variable and did not predict therapeutic success in this larger patient cohort. Rather, a decrease in the frequency of T cells with a naive-like phenotype was consistently observed after immunotherapy and correlated with prolonged patient survival. In contrast, a more detailed clonotypic analysis of emerging and expanding CD8+ T cells in the blood revealed that a majority of individual T cell clones responding to immunotherapy acquired a transcriptional profile consistent with cytolytic effector function. These results suggest that responses to checkpoint blockade immunotherapy are evident and traceable in patients' blood, with outcomes predicted by the simultaneous loss of naive-like CD8+ T cells and the expansion of mostly rare and diverse cytotoxic CD8+ T cell clones.
Sujet(s)
Lymphocytes T CD8+ , Mélanome , Humains , Inhibiteurs de points de contrôle immunitaires/pharmacologie , Récepteur-1 de mort cellulaire programmée/métabolisme , Immunothérapie/méthodes , Analyse sur cellule unique , Microenvironnement tumoralRÉSUMÉ
Single-cell RNA sequencing (scRNAseq) technology is still relatively new in the field of gastric cancer immunology but gaining significant traction. This technology now provides unprecedented insights into the intratumoral and intertumoral heterogeneities at the immunological, cellular, and molecular levels. Within the last few years, a volume of publications reported the usefulness of scRNAseq technology in identifying thus far elusive immunological mechanisms that may promote and impede gastric cancer development. These studies analyzed datasets generated from primary human gastric cancer tissues, metastatic ascites fluid from gastric cancer patients, and laboratory-generated data from in vitro and in vivo models of gastric diseases. In this review, we overview the exciting findings from scRNAseq datasets that uncovered the role of critical immune cells, including T cells, B cells, myeloid cells, mast cells, ILC2s, and other inflammatory stromal cells, like fibroblasts and endothelial cells. In addition, we also provide a synopsis of the initial scRNAseq findings on the interesting epithelial cell responses to inflammation. In summary, these new studies have implicated roles for T and B cells and subsets like NKT cells in tumor development and progression. The current studies identified diverse subsets of macrophages and mast cells in the tumor microenvironment, however, additional studies to determine their roles in promoting cancer growth are needed. Some groups specifically focus on the less prevalent ILC2 cell type that may contribute to early cancer development. ScRNAseq analysis also reveals that stromal cells, e.g., fibroblasts and endothelial cells, regulate inflammation and promote metastasis, making them key targets for future investigations. While evaluating the outcomes, we also highlight the gaps in the current findings and provide an assessment of what this technology holds for gastric cancer research in the coming years. With scRNAseq technology expanding rapidly, we stress the need for periodic review of the findings and assess the available scRNAseq analytical tools to guide future work on immunological mechanisms of gastric carcinogenesis. .
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Immunité innée , Tumeurs de l'estomac , Carcinogenèse/génétique , Cellules endothéliales/anatomopathologie , Humains , Inflammation , Lymphocytes , Analyse de séquence d'ARN , Microenvironnement tumoral/génétiqueRÉSUMÉ
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019. Few studies have compared replication dynamics and host responses to SARS-CoV-2 in cell lines from different tissues and species. Therefore, we investigated the role of tissue type and antiviral genes during SARS-CoV-2 infection in nonhuman primate (kidney) and human (liver, respiratory epithelial, gastric) cell lines. We report different viral growth kinetics and release among the cell lines despite comparable ACE2 expression. Transcriptomics revealed that absence of STAT1 in nonhuman primate cells appeared to enhance inflammatory responses without effecting infectious viral titer. Deletion of RL-6 in respiratory epithelial cells increased viral replication. Impaired infectious virus release was detected in Huh7 but not Huh7.5 cells, suggesting a role for RIG1. Gastric cells MKN45 exhibited robust antiviral gene expression and supported viral replication. Data here provide insight into molecular pathogenesis of and alternative cell lines for studying SARS-CoV-2 infection.
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BACKGROUND & AIMS: It is well established that chronic inflammation promotes gastric cancer-associated metaplasia, but little is known regarding the mechanisms by which immune cells and cytokines regulate metaplastic cellular changes. The goals of this study were to identify interleukin 13 (IL13)-producing immune cells, determine the gastric epithelial cell response(s) to IL13, and establish the role(s) of IL13 in metaplasia development. METHODS: Experiments used an established mouse model of autoimmune gastritis (TxA23), TxA23×Il4ra-/- mice, which develop gastritis but do not express the IL4/IL13-receptor subunit IL4Rα, and TxA23×Il13-Yfp mice, which express yellow fluorescent protein in IL13-producing cells. Flow cytometry was used to measure IL13 secretion and identify IL13-producing immune cells. Mouse and human gastric organoids were cultured with IL13 to determine epithelial cell response(s) to IL13. Single-cell RNA sequencing was performed on gastric epithelial cells from healthy and inflamed mouse stomachs. Mice with gastritis were administered IL13-neutralizing antibodies and stomachs were analyzed by histopathology and immunofluorescence. RESULTS: We identified 6 unique subsets of IL13-producing immune cells in the inflamed stomach. Organoid cultures showed that IL13 acts directly on gastric epithelium to induce a metaplastic phenotype. IL4Rα-deficient mice did not progress to metaplasia. Single-cell RNA sequencing determined that gastric epithelial cells from IL4Rα-deficient mice up-regulated inflammatory genes but failed to up-regulate metaplasia-associated transcripts. Neutralization of IL13 significantly reduced and reversed metaplasia development in mice with gastritis. CONCLUSIONS: IL13 is made by a variety of immune cell subsets during chronic gastritis and promotes gastric cancer-associated metaplastic epithelial cell changes. Neutralization of IL13 reduces metaplasia severity during chronic gastritis.
Sujet(s)
Gastrite , Interleukine-13 , Animaux , Cellules épithéliales/anatomopathologie , Muqueuse gastrique/anatomopathologie , Gastrite/anatomopathologie , Interleukine-13/métabolisme , Métaplasie/anatomopathologie , SourisRÉSUMÉ
Gastric cancer is a leading cause of mortality worldwide. The risk of developing gastric adenocarcinoma, which comprises >90% of gastric cancers, is multifactorial, but most associated with Helicobacter pylori infection. Autoimmune gastritis is a chronic autoinflammatory syndrome where self-reactive immune cells are activated by gastric epithelial cell autoantigens. This cause of gastritis is more so associated with the development of neuroendocrine tumors. However, in both autoimmune and infection-induced gastritis, high risk metaplastic lesions develop within the gastric mucosa. This warrants concern for carcinogenesis in both inflammatory settings. There are many similarities and differences in disease progression between these two etiologies of chronic gastritis. Both diseases have an increased risk of gastric adenocarcinoma development, but each have their own unique comorbidities. Autoimmune gastritis is a primary cause of pernicious anemia, whereas chronic infection typically causes gastrointestinal ulceration. Both immune responses are driven by T cells, primarily CD4+ T cells of the IFN-γ producing, Th1 phenotype. Neutrophilic infiltrates help clear H. pylori infection, but neutrophils are not necessarily recruited in the autoimmune setting. There have also been hypotheses that infection with H. pylori initiates autoimmune gastritis, but the literature is far from definitive with evidence of infection-independent autoimmune gastric disease. Gastric cancer incidence is increasing among young women in the United States, a population at higher risk of developing autoimmune disease, and H. pylori infection rates are falling. Therefore, a better understanding of these two chronic inflammatory diseases is needed to identify their roles in initiating gastric cancer.
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Mast cells are an essential part of the immune system and are best known as important modulators of allergic and anaphylactic immune responses. Upon activation, mast cells release a multitude of inflammatory mediators with various effector functions that can be both protective and damage-inducing. Mast cells can have an anti-inflammatory or pro-inflammatory immunological effect and play important roles in regulating autoimmune diseases including rheumatoid arthritis, type 1 diabetes, and multiple sclerosis. Importantly, chronic inflammation and autoimmunity are linked to the development of specific cancers including pancreatic cancer, prostate cancer, colorectal cancer, and gastric cancer. Inflammatory mediators released from activated mast cells regulate immune responses and promote vascular permeability and the recruitment of immune cells to the site of inflammation. Mast cells are present in increased numbers in tissues affected by autoimmune diseases as well as in tumor microenvironments where they co-localize with T regulatory cells and T effector cells. Mast cells can regulate immune responses by expressing immune checkpoint molecules on their surface, releasing anti-inflammatory cytokines, and promoting vascularization of solid tumor sites. As a result of these immune modulating activities, mast cells have disease-modifying roles in specific autoimmune diseases and cancers. Therefore, determining how to regulate the activities of mast cells in different inflammatory and tumor microenvironments may be critical to discovering potential therapeutic targets to treat autoimmune diseases and cancer.
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The pathogen exposure history of an individual is recorded in their T-cell repertoire and can be accessed through the study of T-cell receptors (TCRs) if the tools to identify them were available. For each T-cell, the TCR loci undergoes genetic rearrangement that creates a unique DNA sequence. In theory these unique sequences can be used as biomarkers for tracking T-cell responses and cataloging immunological history. We developed the immune Cell Analysis Tool (iCAT), an R software package that analyzes TCR sequencing data from exposed (positive) and unexposed (negative) samples to identify TCR sequences statistically associated with positive samples. The presence and absence of associated sequences in samples trains a classifier to diagnose pathogen-specific exposure. We demonstrate the high accuracy of iCAT by testing on three TCR sequencing datasets. First, iCAT successfully diagnosed smallpox vaccinated versus naïve samples in an independent cohort of mice with 95% accuracy. Second, iCAT displayed 100% accuracy classifying naïve and monkeypox vaccinated mice. Finally, we demonstrate the use of iCAT on human samples before and after exposure to SARS-CoV-2, the virus behind the COVID-19 global pandemic. We were able to correctly classify the exposed samples with perfect accuracy. These experimental results show that iCAT capitalizes on the power of TCR sequencing to simplify infection diagnostics. iCAT provides the option of a graphical, user-friendly interface on top of usual R interface allowing it to reach a wider audience.
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COVID-19 , Animaux , Séquençage nucléotidique à haut débit , Humains , Souris , Récepteurs aux antigènes des cellules T/génétique , SARS-CoV-2 , LogicielRÉSUMÉ
Trypanosoma cruzi is the intracellular parasite of Chagas disease, a chronic condition characterized by cardiac and gastrointestinal morbidity. Protective immunity requires CD4+ T cells, and Th1 cells and gamma interferon (IFN-γ) are important players in host defense. More recently, Th17 cells and interleukin 17A (IL-17A) have been shown to exert protective functions in systemic T. cruzi infection. However, it remains unclear whether Th17 cells and IL-17A protect in the mucosa, the initial site of parasite invasion in many human cases. We found that IL-17RA knockout (KO) mice are highly susceptible to orogastric infection, indicating an important function for this cytokine in mucosal immunity to T. cruzi. To investigate the specific role of Th17 cells for mucosal immunity, we reconstituted RAG1 KO mice with T. cruzi-specific T cell receptor transgenic Th17 cells prior to orogastric T. cruzi challenges. We found that Th17 cells provided protection against gastric mucosal T. cruzi infection, indicated by significantly lower stomach parasite burdens. In vitro macrophage infection assays revealed that protection by Th17 cells is reduced with IL-17A neutralization or reversed by loss of macrophage NADPH oxidase activity. Consistently with this, mice lacking functional NADPH oxidase were not protected by Th17 cell transfer. These data are the first report that Th17 cells protect against mucosal T. cruzi infection and identify a novel protective mechanism involving the induction of NADPH oxidase activity by IL-17A. These studies provide important insights for Chagas vaccine development and, more broadly, increase our understanding of the diverse roles of Th17 cells in host defense.
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Maladie de Chagas/immunologie , Muqueuse gastrique/immunologie , Muqueuse gastrique/parasitologie , Interactions hôte-parasite/immunologie , Immunité muqueuse , Cellules Th17/immunologie , Trypanosoma cruzi/immunologie , Animaux , Maladie de Chagas/métabolisme , Maladie de Chagas/parasitologie , Modèles animaux de maladie humaine , Interleukine-17/génétique , Interleukine-17/métabolisme , Activation des lymphocytes/immunologie , Macrophages/immunologie , Macrophages/métabolisme , Macrophages/parasitologie , Souris , Souris knockout , NADPH oxidase/métabolisme , Cellules Th17/métabolismeRÉSUMÉ
Checkpoint blockade immunotherapy relies on the empowerment of the immune system to fight cancer. Why some patients fail to achieve durable clinical responses is not well understood, but unique individual factors such as diet, obesity, and related metabolic syndrome could play a role. The link between obesity and patient outcomes remains controversial and has been mired by conflicting reports and limited mechanistic insight. We addressed this in a C57BL/6 mouse model of diet-induced obesity using a Western diet high in both fats and sugars. Obese mice bearing B16 melanoma or MC38 carcinoma tumors had impaired immune responses to immunotherapy and a reduced capacity to control tumor progression. Unexpectedly, these compromised therapeutic outcomes were independent of body mass and, instead, were directly attributed to dietary fructose. Melanoma tumors in mice on the high-fructose diet were resistant to immunotherapy and showed increased expression of the cytoprotective enzyme heme oxygenase-1 (HO-1). This increase in HO-1 protein was recapitulated in human A375 melanoma cells exposed to fructose in culture. Induced expression of HO-1 shielded tumor cells from immune-mediated killing and was critical for resistance to checkpoint blockade immunotherapy, which could be overcome in vivo using a small-molecule inhibitor of HO-1. This study reveals dietary fructose as a driver of tumor immune evasion, identifying HO-1 expression as a mechanism of resistance and a promising molecular target for combination cancer immunotherapy.See article by Khojandi et al., p. 214.
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Cytoprotection , Résistance aux médicaments antinéoplasiques , Fructose/métabolisme , Tumeurs/métabolisme , Échappement de la tumeur à la surveillance immunitaire , Animaux , Antinéoplasiques immunologiques/usage thérapeutique , Carcinomes , Lignée cellulaire tumorale , Femelle , Heme oxygenase-1/métabolisme , Humains , Mâle , Souris , Souris de lignée C57BL , Tumeurs/traitement médicamenteuxRÉSUMÉ
Zika virus (ZIKV) is a significant global health threat due to its potential for rapid emergence and association with severe congenital malformations during infection in pregnancy. Despite the urgent need, accurate diagnosis of ZIKV infection is still a major hurdle that must be overcome. Contributing to the inaccuracy of most serologically-based diagnostic assays for ZIKV, is the substantial geographic and antigenic overlap with other flaviviruses, including the four serotypes of dengue virus (DENV). Within this study, we have utilized a novel T cell receptor (TCR) sequencing platform to distinguish between ZIKV and DENV infections. Using high-throughput TCR sequencing of lymphocytes isolated from DENV and ZIKV infected mice, we were able to develop an algorithm which could identify virus-associated TCR sequences uniquely associated with either a prior ZIKV or DENV infection in mice. Using this algorithm, we were then able to separate mice that had been exposed to ZIKV or DENV infection with 97% accuracy. Overall this study serves as a proof-of-principle that T cell receptor sequencing can be used as a diagnostic tool capable of distinguishing between closely related viruses. Our results demonstrate the potential for this innovative platform to be used to accurately diagnose Zika virus infection and potentially the next emerging pathogen(s).
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Dengue/diagnostic , Antigène HLA-A2/génétique , Récepteurs aux antigènes des cellules T/métabolisme , Infection par le virus Zika/diagnostic , Animaux , Anticorps antiviraux/sang , Réactions croisées/immunologie , Dengue/sang , Souris , Souris transgéniques , Récepteurs aux antigènes des cellules T/composition chimique , Tests sérologiques/méthodes , Infection par le virus Zika/sangRÉSUMÉ
BACKGROUND & AIMS: Chronic atrophic gastritis can lead to gastric metaplasia and increase risk of gastric adenocarcinoma. Metaplasia is a precancerous lesion associated with an increased risk for carcinogenesis, but the mechanism(s) by which inflammation induces metaplasia are poorly understood. We investigated transcriptional programs in mucous neck cells and chief cells as they progress to metaplasia mice with chronic gastritis. METHODS: We analyzed previously generated single-cell RNA-sequencing (scRNA-seq) data of gastric corpus epithelium to define transcriptomes of individual epithelial cells from healthy BALB/c mice (controls) and TxA23 mice, which have chronically inflamed stomachs with metaplasia. Chronic gastritis was induced in B6 mice by Helicobacter pylori infection. Gastric tissues from mice and human patients were analyzed by immunofluorescence to verify findings at the protein level. Pseudotime trajectory analysis of scRNA-seq data was used to predict differentiation of normal gastric epithelium to metaplastic epithelium in chronically inflamed stomachs. RESULTS: Analyses of gastric epithelial transcriptomes revealed that gastrokine 3 (Gkn3) mRNA is a specific marker of mouse gastric corpus metaplasia (spasmolytic polypeptide expressing metaplasia, SPEM). Gkn3 mRNA was undetectable in healthy gastric corpus; its expression in chronically inflamed stomachs (from TxA23 mice and mice with Helicobacter pylori infection) identified more metaplastic cells throughout the corpus than previously recognized. Staining of healthy and diseased human gastric tissue samples paralleled these results. Although mucous neck cells and chief cells from healthy stomachs each had distinct transcriptomes, in chronically inflamed stomachs, these cells had distinct transcription patterns that converged upon a pre-metaplastic pattern, which lacked the metaplasia-associated transcripts. Finally, pseudotime trajectory analysis confirmed the convergence of mucous neck cells and chief cells into a pre-metaplastic phenotype that ultimately progressed to metaplasia. CONCLUSIONS: In analyses of tissues from chronically inflamed stomachs of mice and humans, we expanded the definition of gastric metaplasia to include Gkn3 mRNA and GKN3-positive cells in the corpus, allowing a more accurate assessment of SPEM. Under conditions of chronic inflammation, chief cells and mucous neck cells are plastic and converge into a pre-metaplastic cell type that progresses to metaplasia.
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Cellules principales de l'estomac/anatomopathologie , Gastrite atrophique/immunologie , Infections à Helicobacter/immunologie , États précancéreux/diagnostic , Tumeurs de l'estomac/prévention et contrôle , Animaux , Marqueurs biologiques/analyse , Marqueurs biologiques/métabolisme , Carcinogenèse/génétique , Carcinogenèse/immunologie , Protéines de transport/analyse , Protéines de transport/métabolisme , Cellules principales de l'estomac/immunologie , Modèles animaux de maladie humaine , Femelle , Gastrite atrophique/microbiologie , Gastrite atrophique/anatomopathologie , Infections à Helicobacter/génétique , Infections à Helicobacter/microbiologie , Infections à Helicobacter/anatomopathologie , Helicobacter pylori/immunologie , Humains , Mâle , Protéines membranaires/analyse , Protéines membranaires/métabolisme , Métaplasie/diagnostic , Métaplasie/génétique , Métaplasie/immunologie , Métaplasie/anatomopathologie , Souris , États précancéreux/génétique , États précancéreux/immunologie , États précancéreux/anatomopathologie , RNA-Seq , Analyse sur cellule unique , Tumeurs de l'estomac/anatomopathologieRÉSUMÉ
BACKGROUND & AIMS: The association between chronic inflammation and gastric carcinogenesis is well established, but it is not clear how immune cells and cytokines regulate this process. We investigated the role of interleukin 27 (IL27) in the development of gastric atrophy, hyperplasia, and metaplasia (preneoplastic lesions associated with inflammation-induced gastric cancer) in mice with autoimmune gastritis. METHODS: We performed studies with TxA23 mice (control mice), which express a T-cell receptor against the H+/K+ adenosine triphosphatase α chain and develop autoimmune gastritis, and TxA23xEbi3-/- mice, which develop gastritis but do not express IL27. In some experiments, mice were given high-dose tamoxifen to induce parietal cell atrophy and spasmolytic polypeptide-expressing metaplasia (SPEM). Recombinant IL27 was administered to mice with mini osmotic pumps. Stomachs were collected and analyzed by histopathology and immunofluorescence; we used flow cytometry to measure IL27 and identify immune cells that secrete IL27 in the gastric mucosa. Single-cell RNA sequencing was performed on immune cells that infiltrated stomach tissues. RESULTS: We identified IL27-secreting macrophages and dendritic cell in the corpus of mice with chronic gastritis (TxA23 mice). Mice deficient in IL27 developed more severe gastritis, atrophy, and SPEM than control mice. Administration of recombinant IL27 significantly reduced the severity of inflammation, atrophy, and SPEM in mice with gastritis. Single-cell RNA sequencing showed that IL27 acted almost exclusively on stomach-infiltrating CD4+ T cells to suppress expression of inflammatory genes. CONCLUSIONS: In studies of mice with autoimmune gastritis, we found that IL27 is an inhibitor of gastritis and SPEM, suppressing CD4+ T-cell-mediated inflammation in the gastric mucosa.