Cellular and Molecular Gastroenterology and Hepatology最新文献

Background and aims: Considering the role of the P2X7 receptor in intestinal inflammation, we examined its potential involvement in fibrosis development.

Methods: Colonic biopsies from patients with inflammatory bowel disease (IBD) were analyzed via double immunofluorescence under confocal microscopy. Colon fibroblasts were used to analyze P2X7 receptor modulation and chemotaxis. Experimental chronic colitis was induced with three cycles of oral dextran sodium sulfate (DSS) treatment in P2X7^+/+ and P2X7^-/- mice. The mice were evaluated via follow-up video endoscopy with an endoluminal ultrasound biomicroscopic (eUBM) system, histological scoring, immunohistochemistry, cytokine measurement in colon explants, gene expression analysis of P2X7 signaling targets via qRT‒PCR, and microbiome composition analysis.

Results: Colocalization studies revealed a greater density of P2X7⁺/α-SMA⁺ cells in colon sections from patients than in those from controls, especially in patients with Crohn's disease (p<0.05). Activation of the ATP-P2X7 pathway in human fibroblasts increased cell migration, calcium influx, and collagen production. Video colonoscopy with the eUBM system revealed significantly more inflammation, with greater wall thickness and stiffness, in P2X7^+/+- mice than in P2X7^-/- and P2X7^+/+ mice treated with A740003 (a P2X7-selective inhibitor). P2X7^+/+ mice exhibited increased caspase-1 and NLRP3 expression, as well as NF-κB and ERK activation, accompanied by decreased PPARγ expression. In the supernatants of colon explants, TNF-α, IL-1β, IFN-γ, TGF-β, IL-10, and collagen production were increased in P2X7^+/+ mice. Various microbial changes were observed in P2X7^-/- and P2X7^+/+ mice.

Conclusion: Regulatory mechanisms downstream of P2X7, combined with signals from a dysbiotic microbiota, activate intracellular signaling pathways and the inflammasome, leading to intestinal inflammation and promoting fibrogenesis.

Clinical trial registration:

Background and aims: Loss of keratin 8 (K8) has been shown to increase susceptibility towards colonocyte hyperproliferation and tumorigenesis. However, most colorectal cancer (CRC) mouse models require carcinogen, develop small intestinal tumors or have a long latency period. The aim was to establish a genetic, colon-specific and more human like CRC model driven by loss of K8 and Apc.

Methods: Colon-specific targeting using CDX2P-CreER^T2 mice was used to generate K8^flox/flox; CDX2P-CreER^T2 and K8^flox/flox; CDX2P-CreER^T2; Apc^flox/+ mice. Disease activity was monitored, and colon was analyzed for tumor burden and histopathology over time. Keratin expression, inflammation, proliferation, cell polarity, colonocyte populations and cell division symmetry were assessed using immunoblotting and immunofluorescence analysis. This data was compared to K8 expression analysis in CRC patients and in UALCAN database.

Results: K8^flox/flox; CDX2P-CreER^T2 mice develop mild diarrhea and express reduced K8 and partner keratins in a mosaic pattern in the colonic epithelium. K8-negative colon areas display increased crypt loss and more inflammation predominantly in the proximal colon. Increased colonocyte proliferation is observed throughout the colon. Impaired cell polarity and higher number of stem and progenitor cells with a shift towards asymmetric cell division in K8-negative areas of the distal colon highlight a pro-tumorigenic environment. Mice with additional monoallelic Apc inactivation show colon tumorigenesis and epithelial to mesenchymal transition distally. In CRC patients, tumor K8 expression is decreased independent of disease type and stage, age or gender.

Conclusion: Genetic colon-specific mouse model with loss of K8 and Apc adequately resembles human CRC. This study identifies anti-tumorigenic protective roles of colonocyte K8 in the colon.

Background and aims: Dextran sulfate sodium (DSS)-induced colitis is a widely used model to study ulcerative colitis (UC). However, the extent to which acute versus repeated DSS exposure mimics human disease remains unclear.

Methods: Using histopathology, flow cytometry, single-cell RNA sequencing (scRNA-seq) and 16S rRNA profiling we compared disease outcomes, immune infiltrate, transcriptional programs and changes in the microbiome in mice subjected to a single (acute) versus two (repeated) DSS cycles. We further evaluated which experimental condition better represents key immune cell subtype states in human disease.

Results: While disease activity indices were similar between groups, repeated DSS exposure resulted in greater colon shortening, mucosal remodeling and elevated immune infiltration, particularly by neutrophils (PMNs) in the distal colon. scRNA-seq revealed that PMNs and T cells acquired distinct transcriptional programs in repeated versus acute colitis. Cycle 1 PMNs showed inflammatory and cytotoxic signatures, whereas cycle 2 PMNs were enriched in tissue remodeling and survival pathways. CD4 and CD8 T cells in repeated colitis exhibited migratory, and pathogen-responsive phenotypes, with expanded Treg and exhausted CD8 subsets. In contrast, macrophage numbers decreased with repeated DSS, though remaining cells exhibited pro-resolution gene expression profiles. Microbiome analysis revealed normalization trends with repeated DSS exposure, including reduced pro-inflammatory and increased beneficial genera. Cross-species transcriptomic comparisons indicated cycle-specific overlap with human UC, where cycle 2 activated PMNs and alternatively activated macrophages, closer aligned with active human UC.

Conclusion: Collectively, our data indicate that repeated DSS cycles provide a better experimental colitis model for studying immune cells in UC and identifying distinct immune subtypes relevant to UC therapeutics.

Background and aims: Immune responses to infection must balance pathogen clearance with minimizing tissue damage and autoimmunity. Chronic gastric inflammation caused by H. pylori damages the gastric mucosa and promotes carcinogenesis. Glucocorticoids are immunoregulatory hormones that limit immune activation in the stomach. This study aimed to determine how endogenous glucocorticoids regulate the gastric immune response to Helicobacter infection and their impact on preneoplastic lesion development.

Methods: We examined the role of endogenous glucocorticoids in shaping the gastric immune response to Helicobacter felis colonization. Gastric immune cell infiltration, atrophy, metaplasia, and preneoplastic lesion development were evaluated in adrenal-intact and adrenalectomized (ADX) mice. Auto-reactive IgG antibodies were assessed using a mouse self-antigen array and by measuring their binding to healthy gastric tissue.

Results: Loss of endogenous glucocorticoids led to significantly increased H. felis-induced gastric T cell infiltration and proinflammatory cytokine expression compared to intact-infected controls. While all intact mice maintained chronic infection for up to 12 months post-colonization, nearly all ADX mice eradicated H. felis within 2-3 weeks. Despite bacterial clearance, ADX mice continued to exhibit chronic gastric inflammation and developed dysplasia. Autoantibody profiling showed that both intact and ADX groups generated self-reactive IgG during active infection. However, only ADX mice sustained autoantibody production following bacterial eradication.

Conclusions: Endogenous glucocorticoids attenuate gastric inflammation during Helicobacter infection, supporting bacterial persistence while maintaining immune tolerance. These findings suggest that heightened immune responses to H. pylori may trigger autoimmune gastritis (AIG) development, which can persist after H. pylori clearance and continue to drive gastric cancer risk.

Background & aims: In response to injury, pancreatic acinar cells undergo acinar-to-ductal metaplasia (ADM), marked by loss of acinar identity and acquisition of ductal features. While ADM can resolve to support tissue repair, it may also persist and serve as a precursor to pancreatic cancer. Whether diverse pancreatic stressors drive a shared or context-specific ADM program remains unclear. We sought to comprehensively define metaplastic responses to clinically relevant exocrine pancreas diseases known to increase cancer risk.

Methods: We profiled ADM and the surrounding microenvironment across mouse models of exocrine disease-including acute, recurrent, and chronic pancreatitis, as well as in the setting of oncogenic Kras-capturing over 300,000 single cells. To enable high-quality transcriptomic profiling in enzyme-rich tissue, we leveraged FixNCut, a method that preserves RNA integrity in the exocrine pancreas. Findings were validated in human pancreas tissue using CosMx spatial transcriptomics.

Results: We identify a conserved acinar response across disease contexts that gives rise to previously unrecognized distinct metaplastic states, including a "gateway" ADM population that precedes more advanced metaplastic states marked by complete loss of acinar identity. In pancreatic intraepithelial neoplasia (PanIN) precancerous lesions, we detect classical-like and basal-like states, suggesting that pancreatic cancer subtypes are specified much earlier than previously appreciated. In Kras-mutant tissue, we identify a second wave of inflammation and the emergence of an immunosuppressive niche, coinciding with PanIN formation CONCLUSIONS: Our findings define a conserved program of acinar plasticity across exocrine pancreas diseases. We further link unresolved ADM to immune remodeling during precursor lesion formation and observe the emergence of pancreatic cancer subtypes in early PanIN lesions.

Background & aims: Oral and gut health are tightly connected through their microbiome and immunity, including in disease states. The oral adaptive immunity contributes to the severity of inflammatory bowel disease (IBD). However, the role of oral innate immunity, and more specifically the saliva in gut microbiome and IBD, is poorly understood.

Methods: We used two mouse models with reduced saliva, NOD and Aqp5^-/- mice, and recovery of salivation in the NOD mice by treatment with a CFTR corrector to examine the role of salivation in oral and gut microbiome, IBD, and survival.

Results: Analysis of the oral microbiome at various conditions revealed that the saliva has a minimal role in shaping the oral microbiome. However, salivation affected the composition of the gut microbiome. Moreover, the lack of saliva significantly delayed development of DSS-induced colitis, but resulted in a later, age-dependent, rapidly developed weight loss and death. The dual roles of the saliva were caused by two immunomodulatory peptides secreted by salivary glands. Fractionation and mass spectroscopy analysis identified trefoil factor 2 (TFF2) as a protective component and the cytokine macrophage migration inhibitory factor (MIF) as the damaging component of the saliva. The effects of the salivary fluid, TFF2, and MIF were primarily due to control of the gut barrier, rather than the gut microbiome. Scavenging salivary TFF2 and MIF with antibodies resulted in exacerbating and protection, respectively, of IBD.

Conclusions: The oral innate immunity has a major role in shaping the gut microbiome through secretion of MIF and TFF2. Control of MIF and TFF2 can benefit the treatment of colitis.