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Gastroenterology Feb 2021Immune checkpoint inhibitors have limited efficacy in many tumors. We investigated mechanisms of tumor resistance to inhibitors of programmed cell death-1 (PDCD1, also...
BACKGROUND & AIMS
Immune checkpoint inhibitors have limited efficacy in many tumors. We investigated mechanisms of tumor resistance to inhibitors of programmed cell death-1 (PDCD1, also called PD-1) in mice with gastric cancer, and the role of its ligand, PD-L1.
METHODS
Gastrin-deficient mice were given N-methyl-N-nitrosourea (MNU) in drinking water along with Helicobacter felis to induce gastric tumor formation; we also performed studies with H/K-ATPase-hIL1B mice, which develop spontaneous gastric tumors at the antral-corpus junction and have parietal cells that constitutively secrete interleukin 1B. Mice were given injections of an antibody against PD-1 or an isotype control before tumors developed, or anti-PD-1 and 5-fluorouracil and oxaliplatin, or an antibody against lymphocyte antigen 6 complex locus G (also called Gr-1), which depletes myeloid-derived suppressor cells [MDSCs]), after tumors developed. We generated knock-in mice that express PD-L1 specifically in the gastric epithelium or myeloid lineage.
RESULTS
When given to gastrin-deficient mice before tumors grew, anti-PD-1 significantly reduced tumor size and increased tumor infiltration by T cells. However, anti-PD-1 alone did not have significant effects on established tumors in these mice. Neither early nor late anti-PD-1 administration reduced tumor growth in the presence of MDSCs in H/K-ATPase-hIL-1β mice. The combination of 5-fluorouracil and oxaliplatin reduced MDSCs, increased numbers of intra-tumor CD8 T cells, and increased the response of tumors to anti-PD-1; however, this resulted in increased tumor expression of PD-L1. Expression of PD-L1 by tumor or immune cells increased gastric tumorigenesis in mice given MNU. Mice with gastric epithelial cells that expressed PD-L1 did not develop spontaneous tumors, but they developed more and larger tumors after administration of MNU and H felis, with accumulation of MDSCs.
CONCLUSIONS
In mouse models of gastric cancer, 5-fluorouracil and oxaliplatin reduce numbers of MDSCs to increase the effects of anti-PD-1, which promotes tumor infiltration by CD8 T cells. However, these chemotherapeutic agents also induce expression of PD-L1 by tumor cells. Expression of PD-L1 by gastric epithelial cells increases tumorigenesis in response to MNU and H felis, and accumulation of MDSCs, which promote tumor progression. The timing and site of PD-L1 expression is therefore important in gastric tumorigenesis and should be considered in design of therapeutic regimens.
Topics: Administration, Oral; Animals; Carcinogenesis; Gastric Mucosa; Gastrins; Helicobacter Infections; Helicobacter felis; Humans; Immune Checkpoint Inhibitors; Methylnitrosourea; Mice; Mice, Knockout; Myeloid-Derived Suppressor Cells; Neoplasms, Experimental; Programmed Cell Death 1 Receptor; Signal Transduction; Stomach Neoplasms; Tumor Microenvironment
PubMed: 33129844
DOI: 10.1053/j.gastro.2020.10.036 -
BioRxiv : the Preprint Server For... Dec 2023Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria (HP) is associated with approximately 75% of gastric cancer cases. HP...
BACKGROUND
Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria (HP) is associated with approximately 75% of gastric cancer cases. HP infection induces chronic gastric inflammation, damaging the stomach and fostering carcinogenesis. Most mechanistic studies on induced gastric cancer initiation are performed in mice and utilize either mouse-adapted strains of HP or the natural mouse pathogen (HF). Each of these infection models is associated with strengths and weaknesses. Here, we identified the differences in immunogenicity and gastric pathological changes associated with HP and HF infection in mice.
MATERIAL AND METHODS
PMSS1 HP strain or with the CS1 HF strain were co-cultured with mouse peritoneal macrophages to assess their immunostimulatory effects. C57BL/6J mice were infected with HP or HF, and gastric inflammation, atrophy, and metaplasia development were assessed 2 months post-infection.
RESULTS
HP and HF induced similar cytokine production from cultured mouse peritoneal macrophages. HP-infected mice caused modest inflammation within both the gastric corpus and antrum and did not induce significant atrophy within the gastric corpus. In contrast, HF induced significant inflammation throughout the gastric corpus and antrum. Moreover, HF infection was associated with significant atrophy of the chief and parietal cell compartments and induced expression of pyloric metaplasia markers.
CONCLUSIONS
HP is poorly immunogenic compared to HF. HF induces dramatic CD4+ T cell activation, which is associated with increased gastric cancer risk in humans. Thus, HP studies in mice are better suited for studies on colonization, while HF is more strongly suited for pathogenesis and cancer initiation studies.
PubMed: 38187587
DOI: 10.1101/2023.12.22.573128 -
Disease Models & Mechanisms Feb 2017Gastric colonization with Helicobacter pylori induces diverse human pathological conditions, including superficial gastritis, peptic ulcer disease, mucosa-associated... (Review)
Review
Gastric colonization with Helicobacter pylori induces diverse human pathological conditions, including superficial gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma and its precursors. The treatment of these conditions often relies on the eradication of H. pylori, an intervention that is increasingly difficult to achieve and that does not prevent disease progression in some contexts. There is, therefore, a pressing need to develop new experimental models of H. pylori-associated gastric pathology to support novel drug development in this field. Here, we review the current status of in vivo and ex vivo models of gastric H. pylori colonization, and of Helicobacter-induced gastric pathology, focusing on models of gastric pathology induced by H. pylori, Helicobacter felis and Helicobacter suis in rodents and large animals. We also discuss the more recent development of gastric organoid cultures from murine and human gastric tissue, as well as from human pluripotent stem cells, and the outcomes of H. pylori infection in these systems.
Topics: Animals; Disease Models, Animal; Helicobacter Infections; Helicobacter pylori; Humans; Stomach; Stomach Diseases
PubMed: 28151409
DOI: 10.1242/dmm.027649 -
Turkish Journal of Biology = Turk... 2021Regulatory B cells (Bregs) produce antiinflammatory cytokines and inhibits proinflammatory response. Recently, immunosuppressive roles of Bregs in the effector functions...
Regulatory B cells (Bregs) produce antiinflammatory cytokines and inhibits proinflammatory response. Recently, immunosuppressive roles of Bregs in the effector functions of dendritic cells (DCs) were demonstrated. However, cross talk between Bregs and DCs in infection remains unknown. Here, we showed that direct stimulation of bone marrow-derived DCs (BM-DCs) with () antigen upregulates their CD86 surface expression and causes the production of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), interleukin-12 (IL-12), and interleukin-10 (IL-10). Furthermore, prestimulation of DCs with supernatants derived from both -stimulated IL-10 B ( -IL-10 B) or IL-10 B ( -IL-10) cells suppresses the secretion of TNF-α and IL-6, but does not affect the expression of CD86 and secretion of IL-12 by lipopolysaccharide (LPS) or -activated BM-DCs. Remarkably, soluble factors secreted by -IL-10 B cells, but not by -IL-10 B cells, suppress the secretion of IL-10 by BM-DCs upon subsequent LPS stimulation. In contrast, prestimulation with BM-DCs with supernatants of -IL-10 B cells before antigen stimulation induces significantly their IL-10 production. Collectively, our data indicated that prestimulation with soluble factors secreted by -IL-10 B cells, DCs exhibit a tolerogenic phenotype in response to LPS or antigen by secreting high levels of IL-10, but decreased levels of IL-6 and TNF-α.
PubMed: 33907502
DOI: 10.3906/biy-2012-11 -
Microbiology Spectrum Apr 2024Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria (HP) is associated with approximately 75% of gastric cancer cases. HP...
UNLABELLED
Gastric cancer is the fifth most diagnosed cancer in the world. Infection by the bacteria (HP) is associated with approximately 75% of gastric cancer cases. HP infection induces chronic gastric inflammation, damaging the stomach and fostering carcinogenesis. Most mechanistic studies on gastric cancer initiation are performed in mice and utilize either mouse-adapted strains of HP or the natural mouse pathogen (HF). Here, we identified the differences in gastric inflammation, atrophy, and metaplasia associated with HP and HF infection in mice. PMSS1 HP strain or the CS1 HF strain were co-cultured with mouse peritoneal macrophages to assess their immunostimulatory effects. HP and HF induced similar cytokine production from cultured mouse peritoneal macrophages revealing that both bacteria exhibit similar immunostimulatory effects . Next, C57BL/6J mice were infected with HP or HF and were assessed 2 months post-infection. HP-infected mice caused modest inflammation within both the gastric corpus and antrum, and did not induce significant atrophy within the gastric corpus. In contrast, HF induced significant inflammation throughout the gastric corpus and antrum. Moreover, HF infection was associated with significant atrophy of the chief and parietal cell compartments and induced the expression of pyloric metaplasia (PM) markers. HP is poorly immunogenic compared to HF. HF induces dramatic CD4+ T cell activation, which is associated with increased gastric cancer risk in humans. Thus, HP studies in mice are better suited for studies on colonization, while HF is more strongly suited for studies on the effects of gastric inflammation on tumorigenesis. .
IMPORTANCE
Mouse infection models with species are widely used to study pathogenesis and gastric cancer initiation. However, is not a natural mouse pathogen, and mouse-adapted strains are poorly immunogenic. In contrast, is a natural mouse pathogen that induces robust gastric inflammation and is often used in mice to investigate gastric cancer initiation. Although both bacterial strains are widely used, their disease pathogenesis in mice differs dramatically. However, few studies have directly compared the pathogenesis of these bacterial species in mice, and the contrasting features of these two models are not clearly defined. This study directly compares the gastric inflammation, atrophy, and metaplasia development triggered by the widely used PMSS1 and CS1 . felis strains in mice. It serves as a useful resource for researchers to select the experimental model best suited for their studies.
PubMed: 38682907
DOI: 10.1128/spectrum.00015-24 -
Methods in Molecular Biology (Clifton,... 2012Animal models are essential for in vivo analysis of Helicobacter-related diseases. Transgenic mice and Mongolian gerbil models have been the corner stone of present... (Review)
Review
Animal models are essential for in vivo analysis of Helicobacter-related diseases. Transgenic mice and Mongolian gerbil models have been the corner stone of present research focusing on both bacterial virulence factors and host response to infection. Establishing a reproducible rodent model of persistent Helicobacter pylori infection that resembles the H. pylori-associated gastritis observed in humans was a considerable challenge until Lee et al. (Gastroenterology 112:1386-1397, 1997) successfully adapted a clinical Cag A- and Vac A-expressing strain for the mouse stomach. This so-called SS1 (Sydney) strain has since been extensively used for H. pylori research; other rodent-adapted Helicobacter strains have subsequently been developed and utilized in wild-type and genetically engineered rodent models. These bacteria include both H. pylori and the larger but related species H. felis (originally isolated from cats). In this chapter we focus mainly on these two Helicobacter strains and review the rodent models that have been employed to investigate how Helicobacter species induce gastric inflammation and disease.
Topics: Animals; Disease Models, Animal; Helicobacter Infections; Humans; Inflammation; Species Specificity; Stomach Neoplasms
PubMed: 23015495
DOI: 10.1007/978-1-62703-005-2_12 -
Journal of Personalized Medicine Jan 2022The genus is composed of bacteria that colonize both the human and animal gastrointestinal tract. infects half of the world's population, causing various disorders,...
The genus is composed of bacteria that colonize both the human and animal gastrointestinal tract. infects half of the world's population, causing various disorders, such as gastritis, duodenitis and gastric cancer. Additionally, non- species (NHPH) are commonly found in the stomach of pigs, dogs and cats. Most of these species have zoonotic potential and prevalence rates of 0.2-6.0%, and have been described in human patients suffering from gastric disorders undergoing a gastric biopsy. The aim of this study was to determine the occurrence of spp. in the stomach of patients with gastric cancer ( = 17) and obese ( = 63) patients. Furthermore, the outcome of the eradication treatment and the current infection status was evaluated. Overall, based on the genus-specific PCR followed by sequencing, DNA from spp. was detected in 46.3% of the patients, including single infections with in 43.8% of the patients and mixed infections with and canine- or feline-associated in 2.5%. About 32.5% of the patients had been subjected to previous eradication therapy and the triple standard therapy was the most frequent scheme (42.3%). In 48.0% of the patients who received eradication treatment, bacteria were still detected, including one mixed infection. In 23.1% of the patients who reported that a subsequent test had been performed to confirm the elimination of the bacteria, were still detected. In conclusion, although in a smaller percentage, NHPH may also be present in the human stomach. Thus, specific NHPH screening should be included in the diagnostic routine. The continued presence of in the stomach of patients recently subjected to eradication schemes raises questions about the efficacy of the current treatments.
PubMed: 35207669
DOI: 10.3390/jpm12020181 -
Journal of Cancer Prevention Mar 2016The aim of this study was to evaluate the anti-inflammatory and anti-tumorigenic effect of açai berry after chronic Helicobacter felis colonization in the stomachs of...
BACKGROUND
The aim of this study was to evaluate the anti-inflammatory and anti-tumorigenic effect of açai berry after chronic Helicobacter felis colonization in the stomachs of C57BL/6 mice.
METHODS
A total of 57 four-week-old female C57BL/6 mice (18 control mice and 39 experimental mice) were used. The mice were administered orogastrically with vehicle only or vehicle containing H. felis, 5 times every other day. After inoculation of H. felis, mice were fed either a standard or an açai-containing diet and then sacrificed at 4, 24, and 52 weeks. The infection status and degree of inflammation were determined by culture and histopathology. The level of gastric mucosal myeloperoxidase (MPO), TNF-α, and interleukin-1β (IL-1β) were measured by ELISA.
RESULTS
At 24 weeks after inoculation, mucosal atrophy and mucous metaplasia appeared in all infected mice. At 52 weeks after inoculation, dysplastic change was noted in 10%, 25%, and 50% of mice in the H. felis-control, H. felis-açai 5%, and H. felis-açai 10% groups, respectively. The neutrophil, monocyte, atrophy, and metaplasia grades of infected mice showed no significant difference among the H. felis-infected groups. H. felis-infected mice fed with açai berry showed no significant difference compared with H. felis-infected control mice in gastric mucosal MPO, TNF-α, and IL-1β levels.
CONCLUSIONS
H. felis that colonized the stomachs of C57BL/6 mice provoked inflammation, and induced mucosal atrophy, metaplasia, and dysplasia. However, açai berry did not effectively prohibit the gastric carcinogenesis which was induced by chronic H. felis infection.
PubMed: 27051649
DOI: 10.15430/JCP.2016.21.1.48 -
Frontiers in Immunology 2023MDSCs express SCHLAFEN 4 (SLFN4) in -infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to...
INTRODUCTION
MDSCs express SCHLAFEN 4 (SLFN4) in -infected stomachs coincident with spasmolytic polypeptide-expressing metaplasia (SPEM), a precursor of gastric cancer. We aimed to characterize SLFN4 cell identity and the role of Slfn4 in these cells.
METHODS
Single-cell RNA sequencing was performed on immune cells sorted from PBMCs and stomachs prepared from uninfected and 6-month -infected mice. Knockdown of Slfn4 by siRNA or PDE5/6 inhibition by sildenafil were performed in vitro. Intracellular ATP/GTP levels and GTPase activity of immunoprecipitated complexes were measured using the GTPase-Glo assay kit. The intracellular level of ROS was quantified by the DCF-DA fluorescent staining, and apoptosis was determined by cleaved Caspase-3 and Annexin V expression. mice were generated and infected with . Sildenafil was administered twice over 2 weeks by gavaging infected mice ~4 months after inoculation once SPEM had developed.
RESULTS
was highly induced in both monocytic and granulocytic MDSCs from infected stomachs. Both -MDSC populations exhibited strong transcriptional signatures for type-I interferon responsive GTPases and exhibited T cell suppressor function. SLFN4-containing protein complexes immunoprecipitated from myeloid cell cultures treated with IFNa exhibited GTPase activity. Knocking down Slfn4 or PDE5/6 inhibition with sildenafil blocked IFNa induction of GTP, SLFN4 and NOS2. Moreover, IFNa induction of -MDSC function was inhibited by inducing their reactive oxygen species (ROS) production and apoptosis through protein kinase G activation. Accordingly, in vivo disruption of Slfn4 in mice or pharmacologic inhibition by sildenafil after Helicobacter infection also suppressed SLFN4 and NOS2, reversed T cell suppression and mitigated SPEM development.
CONCLUSION
Taken together, SLFN4 regulates the activity of the GTPase pathway in MDSCs and precludes these cells from succumbing to the massive ROS generation when they acquire MDSC function.
Topics: Mice; Animals; Helicobacter; Myeloid-Derived Suppressor Cells; GTP Phosphohydrolases; Sildenafil Citrate; Reactive Oxygen Species; Helicobacter felis; Metaplasia; Felis; Guanosine Triphosphate
PubMed: 37334372
DOI: 10.3389/fimmu.2023.1139391 -
Veterinary Research Oct 2022Besides Helicobacter pylori, a Gram-negative bacterium that may cause gastric disorders in humans, non-Helicobacter pylori helicobacters (NHPH) may also colonize the...
Besides Helicobacter pylori, a Gram-negative bacterium that may cause gastric disorders in humans, non-Helicobacter pylori helicobacters (NHPH) may also colonize the stomach of humans and animals. In pigs, H. suis can induce gastritis and may play a role in gastric ulcer disease, possibly in association with Fusobacterium gastrosuis. In the present study, gastric samples from 71 slaughtered pigs and 14 hunted free range wild boars were tested for the presence of DNA of F. gastrosuis and gastric Helicobacter species associated with pigs, dogs cats and humans, using species-specific PCR assays, followed by sequencing of the amplicon. These gastric samples were also histopathologically evaluated. Almost all the pigs presented gastritis (95.8%). Helicobacter spp. were detected in 78.9% and F. gastrosuis in 35.2% of the animals. H. suis was the most frequently identified Helicobacter species (57.7% of the animals), followed by a H. pylori-like species (50.7%) and less often H. salomonis and H. felis (each in 2.8% of the animals). H. suis was most often detected in the glandular (distal) part of the stomach (pars oesophagea 9.9%, oxyntic mucosa 35.2%, antral mucosa 40.8%), while the H. pylori-like species was mainly found in the non-glandular (proximal) part of the stomach (pars oesophagea 39.4%, oxyntic mucosa 14.1%, antral mucosa 4.2%). The great majority of wild boars were also affected with gastritis (71.4%) and Helicobacter spp. and F. gastrosuis were detected in 64.3% and 42.9% of the animals, respectively. H. bizzozeronii and H. salomonis were the most frequently detected Helicobacter species, while a H. pylori-like species and H. suis were only occasionally identified. These findings suggest that these microorganisms can colonize the stomach of both porcine species and may be associated with gastric pathology. This should, however, be confirmed through bacterial isolation. This is the first description of the presence of F. gastrosuis DNA in the stomach of wild boars and a H. pylori-like species in the pars oesophagea of the porcine stomach.
Topics: Animals; Dog Diseases; Dogs; Fusobacterium; Gastric Mucosa; Gastritis; Helicobacter; Helicobacter Infections; Helicobacter pylori; Humans; Sus scrofa; Swine; Swine Diseases
PubMed: 36209119
DOI: 10.1186/s13567-022-01101-5