Apoptosis In Gastric Epithelial Cells Research Articles

Effect of acacetin on inhibition of apoptosis in Helicobacter pylori-infected gastric epithelial cell line.

Helicobacter pylori (H. pylori) infection can cause extensive apoptosis of gastric epithelial cells, serving as a critical catalyst in the progression from chronic gastritis, gastrointestinal metaplasia, and atypical gastric hyperplasia to gastric carcinoma. Prompt eradication of H. pylori is paramount for ameliorating the pathophysiological conditions associated with chronic inflammation of the gastric mucosa and the primary prevention of gastric cancer. Acacetin, which has multifaceted pharmacological activities such as anti-cancer, anti-inflammatory, and antioxidative properties, has been extensively investigated across various domains. Nevertheless, the impact and underlying mechanisms of action of acacetin on H. pylori-infected gastric mucosal epithelial cells remain unclear. To explore the defensive effects of acacetin on apoptosis in H. pylori-infected GES-1 cells and to investigate the underlying mechanisms. GES-1 cells were treated with H. pylori and acacetin in vitro. Cell viability was assessed using the CCK-8 assay, cell mortality rate via lactate dehydrogenase assay, alterations in cell migration and healing capacities through the wound healing assay, rates of apoptosis via flow cytometry and TUNEL staining, and expression levels of apoptosis-associated proteins through western blot analysis. H. pylori infection led to decreased GES-1 cell viability, increased cell mortality, suppressed cell migration, increased rate of apoptosis, increased expressions of Bax and cle-caspase3, and decreased Bcl-2 expression. Conversely, acacetin treatment enhanced cell viability, mitigated apoptosis induced by H. pylori infection, and modulated the expression of apoptosis-regulatory proteins by upregulating Bcl-2 and downregulating Bax and cleaved caspase-3. Acacetin significantly improved GES-1 cell viability and inhibited apoptosis in H. pylori-infected GES-1 cells, thereby exerting a protective effect on gastric mucosal epithelial cells.

Cinnamaldehyde alleviates aspirin-induced gastric mucosal injury by regulating pi3k/akt pathway-mediated apoptosis, autophagy and ferroptosis

BackgroundGastric mucosal injury is a chronic and progressive stomach disease that can be caused by nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, there is an urgent need to find safe and effective drugs to prevent gastric mucosal injury due to NSAIDs. Cinnamaldehyde (CA) is a bioactive compound extracted from the rhizome of cinnamon and has various pharmacological functions, including anti-inflammatory, analgesic, antiapoptotic, and antioxidant activities. However, the potential pharmacological effect of CA on gastric mucosal injury remains unknown. PurposeThe aim of this study was to investigate the protective effects of CA on aspirin-induced gastric mucosal injury and to explore its mechanism of action MethodsThe effect of CA on gastric mucosal injury was investigated in vitro and in vivo, in vitro mouse model of gastric mucosal injury induced by aspirin, in vitro model of GES-1 cell injury by aspirin and Erastin. The mechanism of action of CA was determined using Transcriptomics and bioinformatics. ResultsCA exerted its protective effects against gastric mucosal injury by modulating the downstream targets, including mTOR, GSK3β, and NRF2, via the PI3K/AKT signaling pathway to inhibit autophagy, apoptosis, and ferroptosis in the gastric epithelial cells. Further cellular experiments confirmed that the PI3K/AKT pathway was a key target for CA against gastric mucosal injury. ConclusionThis study provides the first evidence of CA, an active compound in cinnamon, possessing therapeutic potential in preventing and treating gastric mucosal injury, with its mechanism involving the regulation of apoptosis, autophagy, and ferroptosis in gastric epithelial cells mediated by the PI3K/AKT signaling pathway.

Association of methylation silencing of ULK2 via epithelial-mesenchymal transition and differentiated gastric cancers.

404 Background: Diffuse-type gastric cancers (DGC) typically have a poor prognosis related to their invasion and metastasis, in which the epithelial–mesenchymal transition (EMT) is the initiation step. ULK2 plays a role in the autophagy initiation, which might provide a survival advantage in cancer cells. Although knock-down of ULK2 reportedly induces autophagy and EMT in a lung cancer cell line, the mechanism of EMT via the downregulation of ULK2, as well as its clinical significance, remains yet unclear. The present study, therefore, aims at clarifying this mechanism and its clinical significance in gastric cancers. Methods: We examined ULK2 mRNA expression in gastric cancer tissues and normal gastric tissues of healthy people. The effects of knock-downed ULK2 were examined in two gastric cancer cells, which were investigated in terms of their gene expression changes by the mRNA microarray. Furthermore, to investigate the carcinogenic process from normal gastric epithelial cells, we used RGE cells, which were conditionally immortalized normal gastric epithelial cells developed from a transgenic rat. Results: ULK2 mRNA expression of gastric cancer tissues was significantly lower than H. pylori-negative normal tissues. ULK2 was strongly expressed in normal tissues and intestinal-type gastric cancers (IGC) but was scarcely expressed in DGC by immunohistochemical staining. Furthermore, we found that the ULK2 methylation level of gastric cancer tissues was higher than H. pylori-negative normal tissues and IGC. Then, we validated whether knock-down of ULK2 could induce autophagy, cell migration, and EMT in NUGC3 and MKN45 cells. Using mRNA microarray analysis, we confirmed that knock-down of ULK2 changed expressions of oncogenic genes associated with cell migration and EMT. Autophagy inhibitor suppressed cell migration and EMT induced by knock-down of ULK2 in NUGC3 and MKN45. Additionally, we found that knock-down of Ulk2 induced apoptosis in normal gastric epithelial cells. Conclusions: Methylation silencing of ULK2 in gastric cancer cells could induce cell migration and EMT by means of autophagy induction, causing transformation to poorly differentiated cancers.

Shaoyao Gancao Decoction Mitigates Helicobacter Pylori-Induced Chronic Atrophic Gastritis by Suppressing MAOB.

Helicobacter pylori (H. pylori) plays an important role in chronic atrophic gastritis (CAG). Interestingly, Shaoyao Gancao decoction (SGD), a traditional Chinese analgesic prescription, has the efficacy of relaxing spasms and relieving pain. Here, we aimed to identify whether SGD alleviates CAG and the underlying mechanism. A CAG mouse model was developed using H. pylori colonization and a high-salt diet. Histological staining was used to study the histopathological damage changes, and RT-qPCR assays the production of inflammatory responses in the gastric mucosa of mice. H. pylori and a high-salt diet induced gastric mucosal damage and apoptosis of gastric mucosal epithelial cells in mice, eliciting a significant inflammatory response. Treatment with SGD alleviated CAG-induced gastric mucosal damage, reduced apoptosis of gastric mucosal epithelial cells, and inhibited the inflammatory response. Bioinformatics was then used to construct the pharmacological network of SGD to explore its potential targets. SGD inhibited inflammatory response in mice with CAG by suppressing the expression of MAOB. Overexpression of MAOB impaired the therapeutic effect of SGD on inflammation in mice with CAG. Collectively, our findings indicated that SGD has the potential to alleviate CAG via downregulating MAOB.

Can Pyomelanin Produced by Pseudomonas aeruginosa Promote the Regeneration of Gastric Epithelial Cells and Enhance Helicobacter pylori Phagocytosis?

Helicobacter pylori (H. pylori) infection is the most common cause of chronic gastritis, peptic ulcers and gastric cancer. Successful colonization of the stomach by H. pylori is related to the complex interactions of these bacteria and its components with host cells. The growing antibiotic resistance of H. pylori and various mechanisms of evading the immune response have forced the search for new biologically active substances that exhibit antibacterial properties and limit the harmful effects of these bacteria on gastric epithelial cells and immune cells. In this study, the usefulness of pyomelanin (PyoM) produced by Pseudomonas aeruginosa for inhibiting the metabolic activity of H. pylori was evaluated using the resazurin reduction assay, as well as in vitro cell studies used to verify the cytoprotective, anti-apoptotic and pro-regenerative effects of PyoM in the H. pylori LPS environment. We have shown that both water-soluble (PyoMsol) and water-insoluble (PyoMinsol) PyoM exhibit similar antibacterial properties against selected reference and clinical strains of H. pylori. This study showed that PyoM at a 1 μg/mL concentration reduced H. pylori-driven apoptosis and reactive oxygen species (ROS) production in fibroblasts, monocytes or gastric epithelial cells. In addition, PyoM enhanced the phagocytosis of H. pylori. PyoMsol showed better pro-regenerative and immunomodulatory activities than PyoMinsol.

Xiaojianzhong decoction attenuates aspirin-induced gastric mucosal injury via the PI3K/AKT/mTOR/ULK1 and AMPK/ULK1 pathways

Context Xiaojianzhong decoction (XJZD), classically prescribed in Chinese medicine, has protective and healing effects on gastric mucosal injury. However, the exact mechanism behind this effect remains unclear. Objective To investigate the effect of XJZD on gastric mucosal injury and explore its underlying mechanisms. Materials and methods C57BL/6 mice were randomized into six groups (n = 10): the control group receiving sterile water, the model (aspirin 300 mg/kg), the XJZD high-dose (12 g/kg), XJZD medium-dose (6 g/kg), XJZD low-dose (3 g/kg) and omeprazole (20 mg/kg) groups, by gavage daily for 14 days. The area of gastric mucosal injury, mucosal injury index and degree of histopathological damage were analysed. Gastric mucosal epithelial cell apoptosis was detected. Epithelial cell autophagy was observed. The expression levels of tight junction proteins and proteins related to apoptosis, autophagy and the pentose phosphate pathway were analysed. Results The results showed that after treatment with XJZD (12, 6 and 3 g/kg), the mucosal injury area was reduced (83.4%, 22.6% and 11.3%), the expression level of ZO-1 and occludin was up-regulated, the apoptosis rate of epithelial cells was reduced (40.8%, 25.4% and 8.7%), the expression of autophagy-related proteins LC3 and Beclin1 was decreased and the expression of p62 was increased, the PI3K/AKT/mTOR/ULK1(ser757) signalling pathway was activated, and the AMPK/ULK1(ser317) signalling pathway was inhibited. In addition, XJZD can antagonize the imbalance of redox homeostasis caused by aspirin and protect the gastric mucosa. Discussion and conclusions XJZD protects against aspirin-induced gastric mucosal injury, implying it to be a potential therapeutic agent.

Weierning, a Chinese patent medicine, improves chronic atrophic gastritis with intestinal metaplasia.

Weierning tablet (WEN) is a traditional Chinese patent medicine widely used in clinical for chronic atrophic gastritis (CAG) therapy for years. However, the underlying mechanisms of WEN on anti-CAG are still unveiled. The present study aimed to elucidate the characteristic function of WEN on anti-CAG and to illuminate its potential mechanism. The CAG model was established by gavage rats with a modeling solution (consisting of 2% sodium salicylate and 30% alcohol) with irregular diets and free access to 0.1% ammonia solution for two months on end. An enzyme-linked immunosorbent assay was used to measure the serum levels of gastrin, pepsinogen, and inflammatory cytokines. qRT-PCR was applied to measure mRNA expressions of IL-6, IL-18, IL-10, TNF-α, and γ-IFN in gastric tissue. Pathological changes and the ultrastructure of gastric mucosa were examined by hematoxylin and eosin staining and transmission electron microscopy, respectively. AB-PAS staining was applied to observe the intestinal metaplasia of gastric mucosa. Immunohistochemistry and Western blot were used to measure the expression levels of mitochondria apoptosis-related proteins and Hedgehog pathway-related proteins in gastric tissues. Expressions of Cdx2 and Muc2 protein were determined by immunofluorescent staining. WEN could dose-dependently lower the serum level of IL-1β and the mRNA expressions of IL-6, IL-8, IL-10, TNF-α, and γ-IFN in gastric tissue. Also, WEN significantly alleviated the collagen deposition in gastric submucosa, regulated the expressions of Bax, Cleaved-caspase9, Bcl2, and Cytochrome c to reduce the apoptosis of gastric mucosa epithelial cells, and maintained the integrity of the gastric mucosal barrier. Moreover, WEN could reduce protein expressions of Cdx2, Muc2, Shh, Gli1, and Smo, and reverse intestinal metaplasia of gastric mucosa to block the progress of CAG. This study demonstrated a positive effect of WEN on improving CAG and reverse intestinal metaplasia. These functions were related to the suppression of gastric mucosal cells' apoptosis and the inhibition of Hedgehog pathways' activation.

The cytosolic DNA sensor AIM2 promotes Helicobacter-induced gastric pathology via the inflammasome.

Helicobacter pylori (H. pylori) infection can trigger chronic gastric inflammation perpetuated by overactivation of the innate immune system, leading to a cascade of precancerous lesions culminating in gastric cancer. However, key regulators of innate immunity that promote H. pylori-induced gastric pathology remain ill-defined. The innate immune cytosolic DNA sensor absent in melanoma 2 (AIM2) contributes to the pathogenesis of numerous autoimmune and chronic inflammatory diseases, as well as cancers including gastric cancer. We therefore investigated whether AIM2 contributed to the pathogenesis of Helicobacter-induced gastric disease. Here, we reveal that AIM2 messenger RNA and protein expression levels are elevated in H. pylori-positive versus H. pylori-negative human gastric biopsies. Similarly, chronic Helicobacter felis infection in wild-type mice augmented Aim2 gene expression levels compared with uninfected controls. Notably, gastric inflammation and hyperplasia were less severe in H. felis-infected Aim2-/- versus wild-type mice, evidenced by reductions in gastric immune cell infiltrates, mucosal thickness and proinflammatory cytokine and chemokine release. In addition, H. felis-driven proliferation and apoptosis in both gastric epithelial and immune cells were largely attenuated in Aim2-/- stomachs. These observations in Aim2-/- mouse stomachs correlated with decreased levels of inflammasome activity (caspase-1 cleavage) and the mature inflammasome effector cytokine, interleukin-1β. Taken together, this work uncovers a pathogenic role for the AIM2 inflammasome in Helicobacter-induced gastric disease, and furthers our understanding of the host immune response to a common pathogen and the complex and varying roles of AIM2 at different stages of cancerous and precancerous gastric disease.

FTO-mediated m6A modification promotes malignant transformation of gastric mucosal epithelial cells in chronic Cag A+ Helicobacter pylori infection.

Cag A+ Helicobacter pylori chronic infection cause malignant transformation of the human gastric mucosa. N6-methyladenosine (m6A) modifications are the most common and abundant mRNA modifications and one of the pathways affecting tumorigenicity and tumor progression. However, the role of m6A modification in the process of chronic H. pylori infection leading to malignant transformation of gastric mucosa is unclear. In this study, we used Cag A- and Cag A+H. pylori chronic infection to establish cellular models in GES-1 cells and analyzed the cellular morphology, proliferation, apoptosis, invasiveness and tumorigenicity of gastric mucosal epithelial cells. The m6A expression levels of GES-1 cells after chronic infection with Cag A- and Cag A+H. pylori were examined, and modifying effect of FTO (the fat mass and obesity-associated protein) on CD44 was verified by MeRIP-qPCR. Finally, the FTO expression changes and m6A expression levels were further validated in clinical gastric cancer tissues. Chronic Cag A+H. pylori-infected GES-1 cells exhibit altered cell morphology, apoptosis inhibition, abnormal proliferation, enhanced migration, colony formation, and increased stem cell-like properties. Meanwhile, FTO and CD44 expression was enhanced, and FTO may induce malignant transformation of gastric mucosa by regulating CD44 mRNA m6A methylation modifications. We verified the effect of chronic stimulation of Cag A+H. pylori on malignant transformation of gastric mucosal epithelium. revealing the possibility of FTO in promoting malignant transformation of gastric mucosa by modifying CD44 mRNA methylation, suggesting that FTO expression is a potential molecule for malignant transformation of gastric mucosal epithelial cells.

Curculigoside attenuates Helicobacter pylori-induced inflammation and apoptosis of gastric mucosal epithelial cells via NF-κB pathway

Purpose: To investigate the possible effects and mechanisms of action of curculigoside (Cur) on gastric ulcers.
 Methods: Human gastric mucosal epithelial GES-1 cells were infected with Helicobacter pylori and then treated with Cur. Cell counting kit 8 (CCK-8), flow cytometry, and immunofluorescence assays were used to investigate the effect of Cur on cell viability and apoptosis after exposure to H. pylori. Inflammation status and reactive oxygen species (ROS) were assessed using enzyme-linked immunoassay (ELISA) and dichlorodihydrofluorescein (DCF) staining, respectively, while immunoblot and immunofluorescence assays were performed to determine the effect of Cur on the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway.
 Results: Cur significantly increased H. pylori-induced cell viability and inhibited H. pylori-induced inflammatory cytokine production (p < 0.01). Furthermore, Cur significantly suppressed H. pylori-induced ROS production and apoptosis (p < 0.01). Through the NF-κB pathway, Cur attenuated H. pylori-induced inflammation and apoptosis of gastric mucosal epithelial cells.
 Conclusion: In H. pylori infection, Cur treatment increases cell viability, reduces inflammatory cytokine production, suppresses ROS production, and inhibits apoptosis via NF-κB pathway. Further investigation using whole animal experiments would be needed to establish the role of Cur in the management of H. pylori-induced gastric ulcers.

CMTM3 protects the gastric epithelial cells from apoptosis and promotes IL-8 by stabilizing NEMO during Helicobacter pylori infection

BackgroundCKLF-like MARVEL transmembrane domain containing 3 (CMTM3) plays an important role in cancer development. Although Helicobacter pylori (H. pylori) infection is a main cause of gastric cancer, the function of CMTM3 during H. pylori infection remains unclear. CMTM3 expression levels in tissues from H. pylori-infected patients and cells co-cultured with H. pylori were analyzed. qRT-PCR and ELISA were used to investigate the effects of CMTM3 on interleukin 8 (IL-8) expression. Annexin V/propidium iodide staining was performed to evaluate the function of CMTM3 in the apoptosis of gastric epithelial cells. Proteomic analysis was performed to explore the underlying mechanism of CMTM3 during H. pylori infection. The interaction between CMTM3 and NEMO was determined via co-immunoprecipitation, HA-ubiquitin pull-down assay, and immunofluorescence.ResultsH. pylori induced a significant increase in CMTM3 expression. CMTM3 inhibited gastric mucosal epithelial cells from apoptosis and increased the expression level of IL-8 during H. pylori infection. KEGG pathway enrichment analysis revealed that differentially expressed proteins were involved in epithelial cell signaling in H. pylori infection. CMTM3 directly interacted with NEMO, which promoted protein stabilization by down-regulation of its ubiquitylation.ConclusionsCMTM3 reduces apoptosis and promotes IL-8 expression in the gastric epithelial cells by stabilizing NEMO during H. pylori infection. These findings characterize a new role for CMTM3 in host–pathogen interactions and provide novel insight into the molecular regulation of NEMO.

Uncovering the role of microRNA671-5p/CDCA7L/monoamine oxidase-A signaling in Helicobacter pylori mediated apoptosis in gastric epithelial cells.

Helicobacter pylori is a gram-negative microaerophilic bacterium and is associated with gastrointestinal diseases ranging from peptic ulcer and gastritis to gastric cancer and mucosa-associated lymphoid tissue lymphoma. In our laboratory, the transcriptomes and miRnomes of AGS cells infected with H. pylori have been profiled, and an miRNA-mRNA network has been constructed. MicroRNA 671-5p is upregulated during H. pylori infection of AGS cells or of mice. In this study, the role of miR-671-5p during infection has been investigated. It has been validated that miR-671-5p targets the transcriptional repressor CDCA7L, which is downregulated during infection (in vitro and in vivo) concomitant with miR-671-5p upregulation. Further, it has been established that the expression of monoamine oxidase A (MAO-A) is repressed by CDCA7L, and that MAO-A triggers the generation of reactive oxygen species (ROS). Consequently, miR-671-5p/CDCA7L signaling is linked to the generation of ROS during H. pylori infection. Finally, it has been demonstrated that ROS-mediated caspase 3 activation and apoptosis that occurs during H. pylori infection, is dependent on the miR-671-5p/CDCA7L/MAO-A axis. Based on the above reports, it is suggested that targeting miR-671-5p could offer a means of regulating the course and consequences of H. pylori infection.

P53 upregulated by HIF-1α promotes gastric mucosal epithelial cells apoptosis in portal hypertensive gastropathy.

Portal hypertensive gastropathy (PHG) is a serious complication of liver cirrhosis and a potential cause of gastrointestinal bleeding. Mucosal apoptosis is an essential pathological feature of PHG. However, whether HIF-1α and p53 are involved in mucosal apoptosis and whether HIF-1α induces PHG by mediating p53 remains unclear. Gastric mucosal injury and apoptosis were examined in PHG patients and animal models. The mechanisms of HIF-1α- and p53-mediated apoptosis were analyzed. The GES-1 cell line was used to elucidate the underlying mechanisms using siRNA knockdown of HIF-1α and p53 in a hypoxic environment in vitro. Epithelial apoptosis, HIF-1α, and p53 were markedly induced in the gastric mucosa of PHG. Apoptosis was attenuated in mice with HIF-1α- and p53-specific inhibitors. Apoptotic signaling factors were markedly induced in the gastric mucosa of PHG. Inhibition of p53 demonstrably attenuated the mucosal apoptosis; however, it did not affect HIF-1α expression. Conversely, targeted deletion of HIF-1α significantly inhibited p53 expression and attenuated the injury and p53-mediated apoptosis. Bax and Bcl-2 expression can be upregulated and downregulated by p53, respectively, to increasecleaved caspase-3 expression, which can be regulated by HIF-1α. These results indicate that HIF-1α regulates the p53-induced mucosal epithelial apoptotic signaling pathway and that HIF-1α and p53 are potential therapeutic targets for PHG.

Astaxanthin Inhibits Oxidative Stress-Induced Ku Protein Degradation and Apoptosis in Gastric Epithelial Cells.

Oxidative stress induces DNA damage which can be repaired by DNA repair proteins, such as Ku70/80. Excess reactive oxygen species (ROS) stimulate the activation of caspase-3, which degrades Ku 70/80. Cells with decreased Ku protein levels undergo apoptosis. Astaxanthin exerts antioxidant activity by inducing the expression of catalase, an antioxidant enzyme, in gastric epithelial cells. Therefore, astaxanthin may inhibit oxidative stress-induced DNA damage by preventing Ku protein degradation and thereby suppressing apoptosis. Ku proteins can be degraded via ubiquitination and neddylation which adds ubiquitin-like protein to substrate proteins. We aimed to determine whether oxidative stress decreases Ku70/80 expression through the ubiquitin–proteasome pathway to induce apoptosis and whether astaxanthin inhibits oxidative stress-induced changes in gastric epithelial AGS cells. We induced oxidative stress caused by the treatment of β-D-glucose (G) and glucose oxidase (GO) in the cells. As a result, the G/GO treatment increased ROS levels, decreased nuclear Ku protein levels and Ku-DNA-binding activity, and induced the ubiquitination of Ku80. G/GO increased the DNA damage marker levels (γ-H2AX; DNA fragmentation) and apoptosis marker annexin V-positive cells and cell death. Astaxanthin inhibited G/GO-induced alterations, including Ku degradation in AGS cells. MLN4924, a neddylation inhibitor, and MG132, a proteasome inhibitor, suppressed G/GO-mediated DNA fragmentation and decreased cell viability. These results indicated that G/GO-induced oxidative stress causes Ku protein loss through the ubiquitin–proteasome pathway, resulting in DNA fragmentation and apoptotic cell death. Astaxanthin inhibited oxidative stress-mediated apoptosis via the reduction of ROS levels and inhibition of Ku protein degradation. In conclusion, dietary astaxanthin supplementation or astaxanthin-rich food consumption may be effective for preventing or delaying oxidative stress-mediated cell damage by suppressing Ku protein loss and apoptosis in gastric epithelial cells.

1α, 25-Dihydroxyvitamin D3 protects gastric mucosa epithelial cells against Helicobacter pylori-infected apoptosis through a vitamin D receptor-dependent c-Raf/MEK/ERK pathway

Context Due to the resistance of Helicobacter pylori to antibiotics, it is difficult to eradicate this pathogenic bacterium from the host. The role of 1α, 25-dihydroxyvitamin D3 (1,25-D3) in H. pylori-infected gastric mucosa epithelial cells remains unknown. Objective This study investigates the protective property of 1,25-D3 against H. pylori-infected apoptosis in gastric mucosa epithelial cells and its potential molecular mechanisms. Materials and methods GES-1 cells were infected with H. pylori SS1 strain (MOI: 100) and treated with 1,25-D3 at 100, 200, and 300 nM for 24 h. Mice were orally gavaged with 108 CFUs of H. pylori and 25 µg/kg 1,25-D3 every other day for 1 month. CCK-8, LDH assay, TUNEL assay and western blot were used to determine the effect of 1,25-D3 on H. pylori-induced apoptosis. Results H. pylori infection decreased cell viability to 59.2%, while 100–300 nM 1,25-D3 increased cell viability to 62.2%, 78.4% and 87.1%, respectively. Compared with positive control (4.53-fold), 1,25-D3 reduced caspase-3 activity to 4.49-, 2.88- and 1.49-fold, reduced caspase-6 activity to 2.36-, 1.88- and 1.50-fold, reduced caspase-9 activity to 4.55-, 2.91- and 2.01-fold. 1,25-D3 alters Bcl-2 family, caspase protein expression and c-Raf/MEK/ERK phosphorylation levels in vivo and in vitro. Suppression of 1,25-D3 in apoptosis was reliant on binding to vitamin D receptor. The pharmacological inhibition of c-Raf/MEK/ERK phosphorylation blocked the anti-apoptotic effect of 1,25-D3. Discussion and conclusion 1,25-D3 protected gastric mucosa epithelial cells against H. pylori-infected apoptosis through a VDR-dependent c-Raf/MEK/ERK pathway.

Helicobacter pylori infection activates Wnt/β-catenin pathway to promote the occurrence of gastritis by upregulating ASCL1 and AQP5

Helicobacter pylori (H. pylori) infection is a well-recognized contributing factor to gastritis, but the underlying mechanisms remain to be established. It is interesting to note that AQP5 was predicted to be highly expressed in intestinal metaplasia (IM) based on H. pylori infection-related microarray data, and the transcription factor ASCL1 was bioinformatically predicted to associate with AQP5. Therefore, the purpose of this study is to evaluate the mechanistic significance of ASCL1 and AQP5 in H. pylori infection of gastritis. Gastritis mouse models were established by H. pylori infection, followed by determination of AQP5 and ASCL1 in gastric mucosa. Besides, the effects of AQP5 on H. pylori-induced gastritis were explored using AQP5−/− mice. It was observed that H. pylori infection elevated expression of AQP5 and ASCL1 in gastric mucosa and gastric epithelial cells (GECs). H. pylori induced AQP5 expression by regulating ASCL1 and activated WNT/β-catenin signaling pathway in GECs. It was also found that AQP5 knockdown suppressed inflammatory response and apoptosis in H. pylori-infected mice. Moreover, H. pylori infection-elevated ASCL1 and AQP5 expression promoted apoptosis and inflammation in GECs. Taken together, the key findings of the present study demonstrate that H. pylori infection activated WNT/β-catenin signaling pathway by upregulating ASCL1/AQP5 to induce gastritis.

Rebamipide attenuates alcohol-induced gastric epithelial cell injury by inhibiting endoplasmic reticulum stress and activating autophagy-related proteins

Apoptosis of gastric mucosa epithelial cells caused by the abuse of alcohol produces injury to the gastric mucosa and acute or chronic gastritis. In recent years, it has been demonstrated that endoplasmic reticulum stress (ERS) is involved in mediating apoptosis, and that autophagy has a protective effect on survival of cells. Rebamipide is a gastric mucosal protectant used to treat gastritis and stomach ulcers. In this study, ethanol was used to overstimulate gastric mucosal epithelial cells and gavage mice. It was found that 400 mmol/L ethanol overstimulation could activate ERS and induce apoptosis (control vs ethanol treatment: 15.24 ± 1.10% vs 33.80 ± 1.47%, P < 0.001); but could not activate the autophagy pathway. Rebamipide intervention can reduce apoptosis rate (20.78 ± 1.63%), and significantly inhibit the activation of ERS and the active ERS-related downstream NF-κB signaling pathway. Additionally, rebamipide can activate the expression of autophagy-related pathway proteins and increase the expression of p-ERK and p-p38. In addition, rebamipide relieved oxidative stress after an ethanol insult. In the present study, molecular evidence of rebamipide inhibition of ERS and regulation of the protein expression of autophagy pathway components were produced using an acute alcoholic gastric mucosal injury model. This model provides a new approach for investigating the effects of rebamipide treatment on alcohol-induced gastric mucosal damage.

2-(2-phenylethyl)chromone-enriched extract of the resinous heartwood of Chinese agarwood (Aquilaria sinensis) protects against taurocholic acid-induced gastric epithelial cells apoptosis through Perk/eIF2α/CHOP pathway

BackgroundInjury of gastric epithelial cells is one of the most important pathological features of bile reflux gastritis. Chinese agarwood (the resinous heartwood of Aquilaria sinensis) has been used to treat stomach problems for thousands of years in China. However, the pathological mechanism of epithelial cells death induced by bile acids and the therapeutic target of Chinese agarwood for improving bile reflux gastritis have not yet been fully clarified. PurposeThis study aimed to investigate the pro-apoptotic effect of taurocholic acid (TCA) by regulating the ER stress pathway. Moreover, the role of Chinese agarwood 2-(2-phenylethyl)chromone-enriched extract (CPE) to inhibit gastric epithelial cell death induced by TCA was also been demonstrated. MethodsWe adopted human gastric epithelial GES-1 cells to explore the mechanism of TCA-induced cell death in vitro. Then the cell viability, apoptosis rate, and protein expressions were evaluated to explore the protective effects of CPE on GES-1 cells by TCA injury. The therapeutic effect of CPE on bile reflux gastritis was further confirmed by the bile reflux mice in vivo. ResultsOur results demonstrated that TCA activated GES-1 cell apoptosis by increased cleavage of caspase-7 and PARP. Further experiments showed that TCA up-regulated endoplasmic reticulum (ER) stress, subsequently triggered the apoptosis of the epithelial cells. Our research explored that CPE is the main effective fraction in Chinese agarwood by preventing the TCA-induced gastric epithelial cell injury. CPE effectively suppressed GES-1 cell apoptosis activated by TCA through inhibiting Perk/eIF2α/CHOP pathway. The anti-apoptotic effect of CPE on gastric mucosa had also been confirmed in vivo. Moreover, the main effective components in CPE corresponding to the protection of epithelial cells were also been identified. ConclusionOur finding suggested that CPE recovered the TCA-induced epithelial cell apoptosis by mediating the activation of ER stress, which explored potential medicine to treat bile reflux gastritis.

Показатели клеточного обновления эпителиоцитов желудка у коренных и пришлых жителей Республики Тыва с атрофическим гастритом

Study Objective: to study the indicators of apoptosis and proliferation in gastric epitheliocytes in indigenous and alien inhabitants of the Republic of Tyva with atrophic and non-atrophic gastritis. Study Design: cross-sectional comparative study in rural areas of the Republic of Tyva. Material and methods. Clinical examination and endoscopic examination with biopsy sampling from the mucosa of the antrum and gastric body were carried out in 61 Tuvinian and 65 alien inhabitants in the village of Saryg-Sep of the Republic of Tyva, of which 91 people had nonatrophic, and 35 — atrophic gastritis. Helicobacter pylori was determined by two methods: morphological and urease. Morphological diagnosis of gastritis was performed in accordance with the modified Sydney classification (1994). The markers of proliferation (Ki67 and PCNA) and apoptosis (bcl-2 and p53) in gastric epithelial cells were assessed by immunohistochemical method. Study Results. H. pylori was found in 85.2% (52 of 61) of the examined natives and 81.5% (of 53 of 65) of the visitors (odds ratio — 1.29; 95% confidence interval: 0.51–3.26, p = 0.75). In both populations, in patients with atrophy in the antrum and gastric body, the apoptosis index p53 was significantly higher than in patients without atrophy. Proliferation indicators Ki67 and PCNA in gastric epithelial cells significantly decreased in patients with atrophic gastritis compared to those in patients without atrophy among Caucasoids, but not among Tuvinians. Conclusion. The obtained results indicate deeper disturbances in the cellular renewal of gastric epitheliocytes in alien inhabitants with atrophic gastritis than in indigenous people with this disease. We suggest that indicators characterizing the proliferation of epitheliocytes in patients with atrophic gastritis may be markers of the risk of developing gastric cancer. Keywords: apoptosis, proliferation, atrophic gastritis.

Regulation of β1-integrin in autophagy and apoptosis of gastric epithelial cells infected with Helicobacter pylori.

Helicobacter pylori infection is an essential factor in the development of human gastric diseases, but its pathogenic mechanism is still unclear. In this work we have showed that, the LC3II levels were increased and β1-integrin levels were decreased in H. pylori-positive human gastric tissue samples and H. pylori co-cultured GES-1 cells. There was significant upregulation of LC3II levels and downregulation of P62 levels in GES-1 cells after β1-integrin knockdown co-cultured with H. pylori. This indicated that β1-integrin downregulation promoted autophagy in GES-1 cells after H. pylori infection. The cell apoptosis rate and poly ADP-ribose polymerase (PARP) and caspase-3 activities were increased in GES-1 cells pretreated with 3-methyladenine (3-MA ) after H. pylori infection. Furthermore, there was a significant decrease in apoptosis of β1-integrin knockdown GES-1 cells co-cultured with H. pylori; apoptosis was also downregulated in β1-integrin knockdown- and 3-MA-treated GES-1 cells co-cultured with H. pylori. Correspondingly, PARP and caspase-3 activities were decreased in β1-integrin knockdown cells co-cultured with H. pylori and β1-integrin knockdown-3-MA-treated-1 cells with H. pylori infection. Thus, β1-integrin is a novel autophagy and apoptosis regulator during H. pylori infection. However, inhibition of autophagy did not reverse the decrease in apoptosis caused by downregulation of β1-integrin.