scholarly journals NEIL2 plays a critical role in limiting inflammation and preserving genomic integrity in H. pylori-infected gastric epithelial cells

2019 ◽  
Author(s):  
Ayse Z Sahan ◽  
Tatiana Venkova ◽  
Ibrahim M. Sayed ◽  
Ellen J Beswick ◽  
Victor E. Reyes ◽  
...  
Keyword(s):  
Dna Damage ◽  
Epithelial Cells ◽  
Oxidative Dna Damage ◽  
Cell Damage ◽  
Expression Profiles ◽  
Critical Role ◽  
Gene Expression Profiles ◽  
Gastric Epithelial Cells ◽  
Down Regulation ◽  
H Pylori

AbstractThe accumulation of Helicobacter pylori infection-induced oxidative DNA damage in gastric epithelial cells is a risk factor for developing gastric cancer (GC); however, the underlying mechanisms remain poorly understood. Here we report that the suppression of NEIL2, an oxidized base-specific mammalian DNA glycosylase, is one such mechanism via which H. pylori infection may fuel the accumulation of DNA damage during the initiation and progression of GC. Using a combination of cultured cell lines and primary cells, we show that expression of NEIL2 is significantly down-regulated after H. pylori infection; such down-regulation was also seen in human gastric biopsies. The H. pylori infection-induced down-regulation of NEIL2 is specific, as Campylobacter jejuni has no such effect. Using gastric organoids isolated from the murine stomach in co-culture studies with live bacteria mimicking the infected stomach lining, we found that H. pylori infection was associated with IL-8 production; this response was more pronounced in Neil2 knockout (KO) mouse cells compared to wild type (WT) cells, suggesting that NEIL2 suppresses inflammation under physiological conditions. Interestingly, DNA damage was significantly higher in Neil2 KO mice compared to WT mice. H. pylori-infected Neil2 KO mice showed higher inflammation and more epithelial cell damage. Computational analysis of gene expression profiles of repair genes in gastric specimens showed the reduction of Neil2 level is linked to the GC progression. Taken together, our data suggest that down-regulation of NEIL2 is a plausible mechanism by which H. pylori infection derails DNA damage repair, amplifies the inflammatory response and initiates GCs.

scholarly journals Helicobacter pylori infection downregulates the DNA glycosylase NEIL2, resulting in increased genome damage and inflammation in gastric epithelial cells

2020 ◽  
Vol 295 (32) ◽  
pp. 11082-11098 ◽  
Author(s):  
Ibrahim M. Sayed ◽  
Ayse Z. Sahan ◽  
Tatiana Venkova ◽  
Anirban Chakraborty ◽  
Dibyabrata Mukhopadhyay ◽  
...  
Keyword(s):  
Dna Damage ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Inflammatory Response ◽  
Oxidative Dna Damage ◽  
Expression Profiles ◽  
Dna Glycosylase ◽  
Gastric Epithelial Cells ◽  
Genome Damage ◽  
H Pylori

Infection with the Gram-negative, microaerophilic bacterium Helicobacter pylori induces an inflammatory response and oxidative DNA damage in gastric epithelial cells that can lead to gastric cancer (GC). However, the underlying pathogenic mechanism is largely unclear. Here, we report that the suppression of Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase that specifically removes oxidized bases, is one mechanism through which H. pylori infection may fuel the accumulation of DNA damage leading to GC. Using cultured cell lines, gastric biopsy specimens, primary cells, and human enteroid-derived monolayers from healthy human stomach, we show that H. pylori infection greatly reduces NEIL2 expression. The H. pylori infection-induced downregulation of NEIL2 was specific, as Campylobacter jejuni had no such effect. Using gastric organoids isolated from the murine stomach in coculture experiments with live bacteria mimicking the infected stomach lining, we found that H. pylori infection is associated with the production of various inflammatory cytokines. This response was more pronounced in Neil2 knockout (KO) mouse cells than in WT cells, suggesting that NEIL2 suppresses inflammation under physiological conditions. Notably, the H. pylori-infected Neil2-KO murine stomach exhibited more DNA damage than the WT. Furthermore, H. pylori-infected Neil2-KO mice had greater inflammation and more epithelial cell damage. Computational analysis of gene expression profiles of DNA glycosylases in gastric specimens linked the reduced Neil2 level to GC progression. Our results suggest that NEIL2 downregulation is a plausible mechanism by which H. pylori infection impairs DNA damage repair, amplifies the inflammatory response, and initiates GC.

scholarly journals N-Acetylcysteine Reduces ROS-Mediated Oxidative DNA Damage and PI3K/Akt Pathway Activation Induced by Helicobacter pylori Infection

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Chuan Xie ◽  
Jian Yi ◽  
Jing Lu ◽  
Muwen Nie ◽  
Meifang Huang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Gastric Mucosa ◽  
Epithelial Cells ◽  
Oxidative Dna Damage ◽  
Akt Pathway ◽  
Gastric Epithelial Cells ◽  
H Pylori

Background. H. pylori infection induces reactive oxygen species- (ROS-) related DNA damage and activates the PI3K/Akt pathway in gastric epithelial cells. N-Acetylcysteine (NAC) is known as an inhibitor of ROS; the role of NAC in H. pylori-related diseases is unclear. Aim. The aim of this study was to evaluate the role of ROS and the protective role of NAC in the pathogenesis of H. pylori-related diseases. Method. An in vitro coculture system and an in vivo Balb/c mouse model of H. pylori-infected gastric epithelial cells were established. The effects of H. pylori infection on DNA damage and ROS were assessed by the comet assay and fluorescent dichlorofluorescein assay. The level of PI3K/Akt pathway-related proteins was evaluated by Western blotting. The protective role of N-acetylcysteine (NAC) was also evaluated with in vitro and in vivo H. pylori infection models. Results. The results revealed that, in vitro and in vivo, H. pylori infection increased the ROS level and induced DNA damage in gastric epithelial cells. NAC treatment effectively reduced the ROS level and inhibited DNA damage in GES-1 cells and the gastric mucosa of Balb/c mice. H. pylori infection induced ROS-mediated PI3K/Akt pathway activation, and NAC treatment inhibited this effect. However, the gastric mucosa pathological score of the NAC-treated group was not significantly different from that of the untreated group. Furthermore, chronic H. pylori infection decreased APE-1 expression in the gastric mucosa of Balb/c mice. Conclusions. An increased ROS level is a critical mechanism in H. pylori pathogenesis, and NAC may be beneficial for the treatment of H. pylori-related gastric diseases linked to oxidative DNA damage.

scholarly journals Rabeprazole inhibits inflammatory reaction by inhibition of cell pyroptosis in gastric epithelial cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jing Xie ◽  
Long Fan ◽  
Liya Xiong ◽  
Peiyu Chen ◽  
Hongli Wang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Clinical Sample ◽  
Critical Role ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammasome Activation ◽  
Peptic Ulcers ◽  
Gastric Epithelial Cells ◽  
Caspase 1 ◽  
H Pylori

Abstract Background Helicobacter pylori (H. pylori) is a common pathogen in development of peptic ulcers with pyroptosis. Rabeprazole, a critical component of standard triple therapy, has been widely used as the first-line regimen for H. pylori infectious treatment. The aim of this study to explore the function of Rabeprazole on cell pyroptosis in vitro. Methods The clinical sample from patients diagnosed with or without H. pylori-infection were collected to analyze by Immunohistochemistry (IHC). Real-time quantitative PCR (qPCR), western blot (WB) and enzyme linked immunosorbent assay (Elisa) were performed to analyze the effect of Rabeprazole on cell pyroptosis, including LDH, IL-1β and IL-18. Results In this study, we showed that Rabeprazole regulated a phenomenon of cell pyroptosis as confirmed by lactate dehydrogenase (LDH) assay. Further results showed that Rabeprazole inhibited cell pyroptosis in gastric epithelial cells by alleviating GSDMD-executed pyroptosis, leading to decrease IL-1β and IL-18 mature and secretion, which is attributed to NLRP3 inflammasome activation inhibition. Further analysis showed that ASC, NLRP3 and Caspase-1, was significantly repressed in response to Rabeprazole stimulation, resulting in decreasing cleaved-caspase-1 expression. Most important, NLRP3 and GSDMD is significantly increased in gastric tissue of patients with H. pylori infection. Conclusion These findings revealed a critical role of Rabeprazole in cell pyroptosis in patients with H. pylori infection, suggesting that targeting cell pyroptosis is an alternative strategy in improving H. pylori treatment.

scholarly journals NEIL2 plays a critical role in limiting inflammation and preserving genomic integrity in H. pylori‐infected gastric epithelial cells

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Ibrahim M. Sayed ◽  
Ayse Z. Sahan ◽  
Tatiana Venkova ◽  
Anirban Chakraborty ◽  
Victor Reyes ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Critical Role ◽  
Gastric Epithelial Cells ◽  
Genomic Integrity ◽  
H Pylori

scholarly journals Epidermal growth factor receptor inhibition downregulates Helicobacter pylori-induced epithelial inflammatory responses, DNA damage and gastric carcinogenesis

Gut ◽  
2017 ◽  
Vol 67 (7) ◽  
pp. 1247-1260 ◽  
Author(s):  
Johanna C Sierra ◽  
Mohammad Asim ◽  
Thomas G Verriere ◽  
M Blanca Piazuelo ◽  
Giovanni Suarez ◽  
...  
Keyword(s):  
Dna Damage ◽  
Epidermal Growth Factor Receptor ◽  
Epithelial Cells ◽  
Growth Factor Receptor ◽  
Inflammatory Cells ◽  
Gastric Carcinogenesis ◽  
Gastric Epithelial Cells ◽  
Egfr Activation ◽  
Epidermal Growth ◽  
H Pylori

ObjectiveGastric cancer is the third leading cause of cancer death worldwide and infection by Helicobacter pylori is the strongest risk factor. We have reported increased epidermal growth factor receptor (EGFR) phosphorylation in the H. pylori-induced human carcinogenesis cascade, and association with DNA damage. Our goal was to determine the role of EGFR activation in gastric carcinogenesis.DesignWe evaluated gefitinib, a specific EGFR inhibitor, in chemoprevention of H. pylori-induced gastric inflammation and cancer development. Mice with genetically targeted epithelial cell-specific deletion of Egfr (EfgrΔepi mice) were also used.ResultsIn C57BL/6 mice, gefitinib decreased Cxcl1 and Cxcl2 expression by gastric epithelial cells, myeloperoxidase-positive inflammatory cells in the mucosa and epithelial DNA damage induced by H. pylori infection. Similar reductions in chemokines, inflammatory cells and DNA damage occurred in infected EgfrΔepi versus Egfrfl/fl control mice. In H. pylori-infected transgenic insulin-gastrin (INS-GAS) mice and gerbils, gefitinib treatment markedly reduced dysplasia and carcinoma. Gefitinib blocked H. pylori-induced activation of mitogen-activated protein kinase 1/3 (MAPK1/3) and activator protein 1 in gastric epithelial cells, resulting in inhibition of chemokine synthesis. MAPK1/3 phosphorylation and JUN activation was reduced in gastric tissues from infected wild-type and INS-GAS mice treated with gefitinib and in primary epithelial cells from EfgrΔepi versus Egfrfl/fl mice. Epithelial EGFR activation persisted in humans and mice after H. pylori eradication, and gefitinib reduced gastric carcinoma in INS-GAS mice treated with antibiotics.ConclusionsThese findings suggest that epithelial EGFR inhibition represents a potential strategy to prevent development of gastric carcinoma in H. pylori-infected individuals.

scholarly journals α-Difluoromethylornithine reduces gastric carcinogenesis by causing mutations in Helicobacter pylori cagY

2019 ◽  
Vol 116 (11) ◽  
pp. 5077-5085 ◽  
Author(s):  
Johanna C. Sierra ◽  
Giovanni Suarez ◽  
M. Blanca Piazuelo ◽  
Paula B. Luis ◽  
Dara R. Baker ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Oxidative Dna Damage ◽  
Mongolian Gerbils ◽  
Gastric Epithelial Cells ◽  
Oncogenic Signaling ◽  
Cytotoxin Associated Gene A ◽  
H Pylori ◽  
Oncogenic Signaling Pathways

Infection by Helicobacter pylori is the primary cause of gastric adenocarcinoma. The most potent H. pylori virulence factor is cytotoxin-associated gene A (CagA), which is translocated by a type 4 secretion system (T4SS) into gastric epithelial cells and activates oncogenic signaling pathways. The gene cagY encodes for a key component of the T4SS and can undergo gene rearrangements. We have shown that the cancer chemopreventive agent α-difluoromethylornithine (DFMO), known to inhibit the enzyme ornithine decarboxylase, reduces H. pylori-mediated gastric cancer incidence in Mongolian gerbils. In the present study, we questioned whether DFMO might directly affect H. pylori pathogenicity. We show that H. pylori output strains isolated from gerbils treated with DFMO exhibit reduced ability to translocate CagA in gastric epithelial cells. Further, we frequently detected genomic modifications in the middle repeat region of the cagY gene of output strains from DFMO-treated animals, which were associated with alterations in the CagY protein. Gerbils did not develop carcinoma when infected with a DFMO output strain containing rearranged cagY or the parental strain in which the wild-type cagY was replaced by cagY with DFMO-induced rearrangements. Lastly, we demonstrate that in vitro treatment of H. pylori by DFMO induces oxidative DNA damage, expression of the DNA repair enzyme MutS2, and mutations in cagY, demonstrating that DFMO directly affects genomic stability. Deletion of mutS2 abrogated the ability of DFMO to induce cagY rearrangements directly. In conclusion, DFMO-induced oxidative stress in H. pylori leads to genomic alterations and attenuates virulence.

Gene Expression Profiles on Hypoxia and Reoxygenation in Rat Gastric Epithelial Cells: A High-Density DNA Microarray Analysis

Digestion ◽  
2006 ◽  
Vol 73 (2-3) ◽  
pp. 89-100 ◽  
Author(s):  
Kazuhiro Katada ◽  
Yuji Naito ◽  
Katsura Mizushima ◽  
Tomohisa Takagi ◽  
Osamu Handa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Microarray Analysis ◽  
Dna Microarray ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
High Density ◽  
Gastric Epithelial Cells ◽  
Dna Microarray Analysis

scholarly journals Centrosome Loss Triggers a Transcriptional Program to Counter Apoptosis-Induced Oxidative Stress

2018 ◽  
Author(s):  
John S Poulton ◽  
Daniel J McKay ◽  
Mark Peifer
Keyword(s):  
Oxidative Stress ◽  
Cellular Response ◽  
Target Genes ◽  
Cell Damage ◽  
Expression Profiles ◽  
Critical Role ◽  
Gene Expression Profiles ◽  
Spindle Assembly ◽  
Redox Balance ◽  
Mitotic Division

AbstractCentrosomes play a critical role in mitotic spindle assembly through their role in microtubule nucleation and bipolar spindle assembly. Loss of centrosomes can impair the ability of some cells to properly conduct mitotic division, leading to chromosomal instability, cell stress, and aneuploidy. Multiple aspects of the cellular response to mitotic error associated with centrosome loss appears to involve activation of JNK signaling. To further characterize the transcriptional effects of centrosome loss, we compared gene expression profiles of wildtype and acentrosomal cells from Drosophila wing imaginal discs. We found elevation of expression of JNK target genes, which we verified at the protein level. Consistent with this, the upregulated gene set showed significant enrichment for the AP1 consensus DNA binding sequence. We also found significant elevation in expression of genes regulating redox balance. Based on those findings, we examined oxidative stress after centrosome loss, revealing that acentrosomal wing cells have significant increases in reactive oxygen species (ROS). We then performed a candidate genetic screen and found that one of the genes upregulated in acentrosomal cells, G6PD, plays an important role in buffering acentrosomal cells against increased ROS and helps protect those cells from cell death. Our data and other recent studies have revealed a complex network of signaling pathways, transcriptional programs, and cellular processes that epithelial cells use to respond to stressors like mitotic errors to help limit cell damage and maintain normal tissue development.

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