Cellular and Molecular Gastroenterology and Hepatology

Patients with gastric intestinal metaplasia (GIM), a precancerous lesion, are at high risk for progressing to gastric cancer. Identifying these patients is critical to enable gastric cancer interception. Current approaches rely primarily on histologic evaluation of GIM severity and extent, which may be improved by incorporating molecular features that distinguish high-risk lesions. Our prior single-cell and spatial transcriptomics study identified differentially expressed genes associated with the highest-risk category of GIM. They included ANPEP expressed in enterocytes and CPS1 and OLFM4 expressed in intestinal stem-like or progenitor cells. We evaluated the protein expression and localization of these three markers to understand the cellular features associated with GIM risk and their spatial distribution within metaplastic tissues. Using multiplex immunofluorescence, whole slide image analysis and confocal microscopy, we examined protein expression from 100 tissue biopsies annotated for metaplasia severity using the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) system. Tissue samples included control gastric tissue, GIM, dysplasia and adenocarcinoma. Quantitative whole slide image analysis demonstrated that CPS1 expression had a modest association with disease severity. Although ANPEP was strongly associated with GIM severity, it was also frequently expressed in stromal regions outside epithelial glands. In contrast, OLFM4 expression was largely restricted to epithelial glands and showed a strong association with increased OLGIM severity. These OLFM4-positive epithelial cells were present in discrete glandular foci that expanded with increasing severity of metaplasia. Within individual metaplastic glands, OLFM4 expression was highest at the gland base with decreased expression toward the gland surface. Overall, these findings identified OLFM4 as a protein marker associated with high-risk GIM. The spatial organization of OLFM4-expressing cells at the base of metaplastic glands and their focal expansion within tissues suggest the presence of a stem cell-like epithelial compartment that may contribute to the progression of GIM towards gastric cancer.

IntroductionBiliary fibrosis and inflammation are central to the pathogenesis of cholangiopathies such as primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Inflammatory and fibrogenic stimuli, such as transforming growth factor-{beta} (TGF{beta}) and lipopolysaccharide (LPS) signaling, drive these processes, but their underlying transcriptional mechanisms in cholangiocytes remain incompletely defined. We investigated the role of Runt-related transcription factor 1 (RUNX1) as a transcriptional co-regulator of fibroinflammatory signaling in cholangiocytes. MethodsHuman PSC-derived cholangiocytes (PSC-Cs) and mouse large biliary epithelial cells (MLEs) were subjected to RUNX1 knockdown or pharmacologic inhibition (Ro5-3335 or AI-10-104). Cytokine secretion was profiled by Luminex multiplexing; RUNX1 genomic binding and protein interactome were assessed by ChIP-qPCR, ChIP-seq, and LC-MS/MS. In vivo, Mdr2-/- mice received Ro5-3335, and cholangiocyte-selective Runx1 knockout mice (Krt19-CreERT) were challenged with a DDC diet, followed by evaluation of fibrosis and inflammation. ResultsRUNX1 expression was significantly increased in cholangiocytes from PSC and PBC patients, and Mdr2-/- mice. RUNX1 knockdown or inhibition reduced IL6, TNF, and other proinflammatory cytokines in PSC-Cs and attenuated TGF{beta}-, LPS-, and TNF-induced Il6 and Ccl2 expression in MLEs. ChIP-qPCR and ChIP-seq revealed TGF{beta}-induced RUNX1 binding to the Il6 promoter and 727 additional genomic sites enriched for fibrosis and inflammatory pathways; predicted upstream regulators included TGF{beta}, TNF, and NF{kappa}B signaling. Proteomic analysis identified TGF{beta}-induced RUNX1 interactions with SMAD2 and NF{kappa}B2. In vivo, Ro5-3335 treatment in Mdr2-/- mice reduced hepatic collagen, ECM gene expression, immune cell infiltration, and serum liver injury markers and bile acids. Similarly, cholangiocyte-specific Runx1 deletion mitigated fibrosis, inflammation, and liver injury in DDC-fed mice. ConclusionRUNX1 is a central transcriptional hub integrating TGF{beta} and inflammatory signals in cholangiocytes. Its inhibition attenuates biliary fibrosis and inflammation in cholestatic models, supporting RUNX1 as a potential therapeutic target in fibroinflammatory cholangiopathies.

The multiple endocrine neoplasia type 1 (MEN1) gene encodes Menin, a nuclear scaffold protein and tumor suppressor that regulates transcription. It is frequently mutated in endocrine neoplasia. MEN1-gastrinomas are aggressive neuroendocrine tumors (NETs) that arise predominantly in the submucosal Brunners glands of the duodenum, an organelle rich in extracellular growth factors. Many duodenal NETs retain wild-type MEN1 allele and nuclear Menin, suggesting post-translational inactivation of its tumor-suppressor function. The Menin C-terminal domain (CTD) contains a conserved phosphorylation site at Ser487 within the first of three nuclear localization signals (NLS1-3). We hypothesized that extracellular signaling regulates Menin by phosphorylating the CTD at Ser487 blocking its nuclear localization. Using CTD deletion mapping, site-directed mutagenesis, and kinase activation in gastric cell lines, we show that loss of NLS1-3 reduces Menins nuclear localization, stability, and repression of GASTRIN. Cell stimulation by epiregulin, forskolin, or phorbol ester induced Menin Ser487 phosphorylation and its nuclear translocation, relieving repression of GASTRIN. The phospho-mimetic S487D mutant remained cytoplasmic and phenocopied CTD deletion of NLS1-3 sustaining de-repression of GASTRIN. These findings showed that Ser487 phosphorylation restricts nuclear accumulation of Menin and functionally links extracellular signaling to post-translational modification of Menin that ultimately contributes to transcriptional derepression and neuroendocrine tumorigenesis. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=127 HEIGHT=200 SRC="FIGDIR/small/717082v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1f96df4org.highwire.dtl.DTLVardef@a1db4borg.highwire.dtl.DTLVardef@4435f9org.highwire.dtl.DTLVardef@3373b3_HPS_FORMAT_FIGEXP M_FIG C_FIG

Regeneration depends on tightly coordinated transcriptional programs governed by a dynamic epigenetic landscape to regulate cell identity, proliferation, and tissue remodelling following injury. The livers highly regenerative due to the ability to rapidly upregulate genes that drive the cell cycle and other genes important for regeneration. Trimethylation of histone 3 lysine 27 (H3K27me3) is deposited by the polycomb repressive complex 2 (PRC2) and many genes occupied by H3K27me3 in their promoters in uninjured livers become induced following PH. Here we test the hypothesis that depleting H3K27me3 by hepatocyte-specific deletion of Embryonic Ectoderm Development (EedHepKO), a key component of PRC2, changes the regenerative response in the liver. We show that Eed eliminates H3K27me3 in hepatocytes, resulting in reduced liver size, increased hepatocyte death, proliferation and fibrosis associated with upregulation of cell cycle and fibrogenic genes. Though these mice are less likely to survive two-thirds partial hepatectomy than wildtype controls, those that do survive increase liver mass faster than WTs. Importantly the genes that are occupied by H3K27me3 in control uninjured livers are upregulated in EEDHepKO and become further induced following PH. These data show that modulation of PRC2 activity disrupts epigenetic patterning, induces liver injury, and alters regenerative outcomes, suggesting that precise control of PRC2 function could be harnessed to enhance regenerative capacity.

Background and AimsThe tumor microenvironment in colorectal cancer (CRC) is richly innervated, yet the contribution of the enteric nervous system (ENS) to CRC biology remains poorly defined. ENS neurons express proenkephalin (PENK), which can be processed by proprotein convertase 1/3 (PCSK1) to generate Methionine-enkephalin (M-ENK), a bioactive peptide with growth-regulatory potential. We hypothesized that an ENS-derived PCSK1-M-ENK axis restrains CRC proliferation through opioid growth factor receptor (OGFr) signaling and is modulated by stress-associated glucocorticoid receptor (GR) signaling and GLP1 receptor (GLP1R) activity. MethodsPublicly available human CRC single-cell RNA-sequencing datasets were analyzed for OGFr expression. PCSK1 and M-ENK expression in murine ENS and tumor-associated tissue was assessed by immunofluorescence. Functional studies were performed using murine CRC organoids, and primary murine ENS neurons in mono- and co-culture. CRC proliferation was quantified by EdU incorporation following treatment with recombinant M-ENK, recombinant PCSK1, OGFr synthetic ligand naloxone, or PCSK1 inhibitors. Effects of dexamethasone and liraglutide on PCSK1 expression in ENS-containing murine tissue were evaluated. ResultsOGFr was enriched in CRC cells and positively associated with KRAS gene expression. A subset of adult murine colonic myenteric neurons expressed PCSK1 and M-ENK. M-ENK dose-dependently suppressed proliferation of CRC organoid cells. ENS neurons also suppressed CRC proliferation in a PCSK1-dependent manner. Dexamethasone reduced, whereas liraglutide increased, PCSK1 expression. ConclusionsThese findings define a previously unrecognized ENS-derived neuro-oncologic pathway that is associated with reduced CRC cell proliferation and identify the GR/GLP1R-PCSK1-M-ENK axis as a potentially actionable therapeutic node. SummaryThis study identifies a neuronal PCSK1 - M-ENK pathway in the ENS that directly suppresses colorectal cancer growth through local OGFr activation, revealing a previously unrecognized neuropeptidergic mechanism of tumor control within the intestinal microenvironment.

Background: Gastric cancer surveillance in CDH1 pathogenic variant carriers is challenging, as predictors of localized (stage T1a) and advanced (stage >T1a) signet ring cell carcinoma (SRCC) are not well defined. We established the Group of investigAtors STriving toward Research In CDH1 (GASTRIC) consortium to identify clinicopathological factors associated with localized and advanced SRCC. Methods: A retrospective observational study (1998-2025) of CDH1 carriers across twelve academic centers was performed. Clinical, endoscopic, and pathological data were compared between carriers with and without SRCC on endoscopy, and between those with advanced versus localized or no cancer on gastrectomy specimens. Results: Overall, 390 CDH1 carriers from 235 families were included. Presence of SRCCs on endoscopy was significantly associated with thickened folds, nodularity, masses, and intestinal metaplasia, while gastritis was negatively associated. Of 196 carriers (52.4%) undergoing gastrectomy, 11 (5.6%) had advanced cancers, 10(90.9%) of which showed endoscopic abnormalities. Identification of SRCC on baseline endoscopy was the most sensitive feature for advanced disease (0.81) but had moderate specificity (0.74), whereas masses and thickened folds were highly specific (0.99 and 0.96, respectively) but less sensitive. Negative predictive values were high (0.94-1.0), while positive predictive values were modest (0.13-0.66). On multivariate analysis, masses and SRCC foci on baseline endoscopy were independent predictors of advanced disease. Conclusion: Among CDH1 carriers, absence of endoscopic findings was reassuring, whereas significance of detected endoscopic and pathological abnormalities was less certain. Advanced cancer occurred in a small number of carriers, with endoscopic abnormalities in nearly all cases. Endoscopic surveillance might be an alternative to surgery in carriers without worrisome mucosal findings.

Intestinal epithelial cells are central players in mucosal barrier integrity and host-microbe interactions. Genetic studies have revealed that epithelial dysfunction is a key contributor to the pathogenesis of inflammatory bowel disease. Non-SMC condensin II complex subunit D3 (NCAPD3) is essential for chromatin organization and stability. NCAPD3 also promotes antimicrobial defense and autophagy responses in vitro. NCAPD3 expression is decreased in intestinal epithelial cells from patients with ulcerative colitis; however, it is not known whether loss of NCAPD3 expression drives intestinal barrier dysfunction or is a result of disease-associated inflammation. To investigate this relationship in vivo, a tissue-specific approach was required, as global constitutive knockout of NCAPD3 is embryonic lethal. Therefore, a transgenic mouse line with doxycycline-inducible expression of a short hairpin RNA targeting NCAPD3 restricted to villin-expressing cells was generated (NCAPD3KD mice) to enable the study of NCAPD3 function in the intestinal epithelium. Treatment of NCAPD3KD mice with 9-tert-butyl doxycycline resulted in [~]75% reduction of NCAPD3 protein in EpCAM+ intestinal cells. Short-term epithelial NCAPD3 knockdown did not induce spontaneous colitis but was associated with increased serum amyloid A and a trend towards increased intestinal permeability. Upon dextran sodium sulfate or Salmonella enterica serovar Typhimurium {Delta}AroA challenge, NCAPD3KD mice exhibited exacerbated weight loss, higher disease activity, increased histopathological damage, abnormal colonic cytokines and chemokines, and significantly increased intestinal permeability. These results indicate that NCAPD3 expression in the intestinal epithelium is required for optimal barrier maintenance and antimicrobial defense under chemical or microbial stress. These findings support prior in vitro observations and solidify NCAPD3 as a regulator of intestinal epithelial barrier function and mucosal host defense. Author SummaryNCAPD3 is a multifunctional protein with established roles in chromatin organization, genome stability, mitochondrial function, and antimicrobial defense. Dysregulated NCAPD3 is implicated in human diseases, such as inflammatory bowel disease (IBD) and microcephaly; however, due to its essential role in cellular division, determination of whether NCAPD3 loss drives these pathologies in vivo has been lacking. Using a new transgenic mouse model that selectively reduces NCAPD3 expression in intestinal epithelial cells, our study establishes NCAPD3 as an epithelial regulator of the mammalian intestine that enhances epithelial barrier resilience and antimicrobial defense during stress. Although dispensable for short-term basal homeostasis, NCAPD3 function becomes critical during epithelial injury and enteric infection. Reduced NCAPD3 expression may therefore lower the threshold for inflammatory disease by weakening barrier integrity, amplifying inflammatory cascades, and impairing antimicrobial defenses. These findings position NCAPD3 as a potential modulator of IBD susceptibility and highlight chromatin organization as an important, previously underappreciated layer of intestinal epithelial regulation.

Stem cells are critical for the development and maintenance of tissue integrity. An important example is intestinal stem cells (ISCs) that generate all epithelial cell types necessary for formation of the intestinal lining. HAT1, a histone acetyltransferase that acetylates newly synthesized histone H4 molecules on lysine residues 5 and 12 during replication-coupled chromatin assembly, is specifically expressed in intestinal stem and progenitor cells located in intestinal crypts. To determine if HAT1 is important for intestinal stem and progenitor cell function, we generated an inducible deletion of the HAT1 gene in intestinal epithelial cells. Loss of HAT1 resulted in morphological defects in the proximal end of the small intestine. Following loss of HAT1, intestinal crypts became elongated, with an increase in stem and progenitor cell proliferation and an increase in the population of OLFM+ cells. Loss of HAT1 also resulted in alterations in intestinal stem cell differentiation, including an increase in the number of Goblet cells and the mislocalization of Paneth cells into villi. HAT1 is specifically responsible for the acetylation of histone H4 lysine 5 (H4K5ac) in intestinal stem cells. Genome-wide characterization of HAT1-dependent H4K5ac in intestinal crypt cells indicates that the most significant loss of H4K5ac occurs in lamina-associated domains (LADs). Loss of H4K5ac in LADs is accompanied by an increase in histone H3 K9 tri-methylation indicating that HAT1 regulates LAD chromatin structure in intestinal crypt cells. A direct role for HAT1 in intestinal stem cell function was demonstrated using organoids in culture. HAT1 is required for differentiation in organoids and for the maintenance of Lgr5+ stem cells. These results indicate that HAT1 is required for the proper regulation of intestinal stem cell renewal and differentiation.

Circadian rhythms, 24-hour repeating oscillations in daily physiology, are implicated in maintaining intestinal homeostasis. These rhythms are driven by the circadian clock, a molecular timekeeper found throughout cells of the body, including those of the intestinal epithelium. Loss of clock function has been found to worsen colitis; however, it is not clear how the clock impacts regeneration which enables a tissue to return to its homeostatic set point following an injury. To investigate these questions, we used a conditional knockout of the core clock gene, Bmal1, in mouse colon epithelial cells. Our data show that prior to injury Bmal1 promotes colon mucus production, which increases in thickness and within goblet cells when mice are active and begin feeding. Bmal1 loss lowers mucus production but does not drive an apparent tissue phenotype until the system is injured and regenerates itself. In this context, Bmal1 epithelial loss drives a male-specific colitis phenotype and a delay in the ability of colon epithelial cells of both male and female mice to resolve injury to return to their homeostatic set point. Our data suggest that epithelial sex-specific clock rhythms are needed for optimal colon barrier homeostasis.

BackgroundMetabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent pediatric disorder with limited treatment options, primarily due to an incomplete understanding of its molecular drivers. Recent research underscores the role of microbial guilds in metabolic health, but the mechanisms by which dysbiosis driven by core species and co-abundant symbionts disrupt metabolic homeostasis in pediatric MASLD remain unclear. ResultsHere, we conducted integrated metagenomic and metabolomic analyses on 285 pediatric subjects including MASLD patients, obese and healthy controls. The gut dysbiosis in MASLD was characterized by a depletion of Phocaeicola vulgatus, Bacteroides uniformis, Parabacteroides distasonis, and Bacteroides thetaiotaomicron. Co-abundance network analysis, integrating our cohort with four public datasets, identified these species as core guild members associated with MASLD. Microbial enrichment analysis showed significant disruptions in carbohydrate metabolism, particularly the downregulation of the tricarboxylic acid (TCA) cycle, fructose and sucrose metabolism, and pentose and glucuronate interconversions. P. vulgatus and B. uniformis were identified as dominant species linked to the downregulation of KEGG orthologs (KOs) in these disrupted pathways that were inversely correlated with hepatic injury biomarkers. CAZyme database analysis further emphasized P. vulgatus as the primary contributor to glycoside hydrolases involved in monosaccharide utilization. Finally, both untargeted and targeted metabolomics analysis validated a disrupted metabolic network centered on the TCA cycle and monosaccharide metabolism in pediatric MASLD. ConclusionOur findings suggest the core guild species P. vulgatus and B. uniformis may serve as critical regulators of carbohydrate metabolism in pediatric MASLD, offering potential mechanistic targets for gut microbiome-based interventions.

Time-restricted feeding (TRF) is widely considered metabolically beneficial, yet its impact on chronic liver disease progression remains poorly defined. This study investigates the effects of TRF on liver fibrogenesis. Using carbon tetrachloride (CCl4)-induced, bile duct ligation (BDL)-induced, and choline-deficient, L-amino acid-defined high-fat diet (CDAHFD)-induced murine models of liver fibrosis, we demonstrate that TRF consistently exacerbates fibrotic injury. Mechanistically, TRF induces the systemic elevation of the ketone body {beta}-hydroxybutyrate (BHB). We identify the ketolytic enzyme 3-hydroxybutyrate dehydrogenase 1 (BDH1) as a critical mediator of this process within hepatic stellate cells (HSCs). BDH1 expression is markedly upregulated in activated HSCs, enabling these cells to metabolize BHB. This BDH1-dependent ketolysis redirects BHB-derived carbons into the tricarboxylic acid cycle, supplying acetyl-CoA and citrate to drive de novo lipogenesis and support a profibrogenic metabolic state. Both the genetic ablation of Bdh1 specifically in HSCs and the inhibition of hepatic ketogenesis successfully abolished the pro-fibrotic effects of TRF and exogenous BHB administration. Conversely, exogenous BHB alone was sufficient to recapitulate the exacerbated fibrotic phenotype observed with TRF. These findings reveal a context-dependent, detrimental role for TRF during chronic liver injury, driven by BDH1-mediated metabolic reprogramming in HSCs. Consequently, dietary interventions that elevate systemic ketone bodies should be approached with caution in the setting of active liver fibrosis.

Mast cells (MCs) are myeloid cells of the innate immune system. As a first line of defence they fulfill effector functions and immune modulatory properties. Upon activation they release pro-inflammatory mediators such as cytokines and proteases. It has been suggested that MCs may contribute to the development of liver fibrosis. However, investigating hepatic MC biology in mice is challenging due to low MC numbers and a lack of suitable detection techniques relying on MC proteins and their modifications. Here, we evaluated whether the expression strength of MC markers correlates with the degree of liver fibrosis in mice and aimed to determine the frequency and localization of hepatic MCs. We applied both a toxic (DEN/CCl4 treatment) and a genetic (Mdr2-/- mice) liver fibrosis model in C57BL/6 mice and found a significant correlation between fibrosis grade and the expression of several established mast cell markers. This correlation was further supported in patients with fibrosis and hepatocellular carcinoma (HCC) using publicly available transcriptomics datasets. We used FACS to purify and isolate MCs from fibrotic mouse livers and verified MC signatures by qPCR analysis of MC-specific gene expression. Hepatic MCs were predominantly negative for Mast-Cell-Protease 5 (Mcpt5) and occurred at a low frequency (approximately 1-2% of leukocytes). Using Molecular CartographyTM of fibrotic liver sections, we determined the spatial localization, expression signature, abundance (approximately 2 cells/mm2) and cellular environment of murine hepatic MCs. In summary, we demonstrated the existence of MCs in murine fibrotic livers and defined an MC expression signature that correlates with the strength of liver fibrosis. These findings will help to study MC biology in murine models of liver disease more effectively in the future.

Pain in pancreatic ductal adenocarcinoma (PDAC) is associated with poor survival, but whether altered pain processing carries prognostic significance is unknown. We analyzed a prospective cohort of 143 patients with PDAC who underwent pancreatic quantitative sensory testing (PQST) after diagnosis. Patients were classified as having normal pain processing (n=84), segmental hyperalgesia (n=30), or widespread hyperalgesia (n=29). Survival was measured from the date of P-QST assessment. During follow-up, 70 deaths occurred. Widespread hyperalgesia was associated with increased mortality in unadjusted Cox analysis (HR 1.96, 95% CI 1.14,3.35) and after adjustment for age, sex, tumor stage, comorbidity, opioid treatment, and body mass index (adjusted HR 2.33, 95% CI 1.30,4.15). Segmental hyperalgesia was not associated with mortality. Kaplan Meier analysis demonstrated lower survival probability in the widespread hyperalgesia group (log rank p=0.025). These findings suggest that widespread hyperalgesia, reflecting altered central pain processing, identifies a subgroup of PDAC patients at increased risk of mortality independent of conventional clinical factors.

Cirrhosis, the end stage of chronic liver disease marked by fibrosis and impaired liver function, is associated with cirrhosis-associated immune dysfunction, a condition in which systemic inflammation coexists with impaired host defense and increased susceptibility to infections. However, intestinal intraepithelial lymphocytes (IELs), key mediators of epithelial immune defense, remain poorly characterized in this context. Using high-dimensional profiling of paired duodenal biopsies and peripheral blood across disease stages, we define IEL alterations in cirrhosis. Contrary to prior reports of immune exhaustion, lymphocyte effector function was preserved, while disease progression was marked by systemic inflammatory remodeling and increased tumor necrosis factor (TNF) production by circulating T cells. The IEL compartment was markedly altered, with loss of CD8{beta} IELs, expansion of natural killer (NK) IELs, and reduced CCR9CD8{beta} IELs, suggesting altered gut homing. These findings refine cirrhosis-associated immune dysfunction as inflammatory immune reprogramming coupled to impaired epithelial immune surveillance. HighlightsPeripheral lymphocytes from cirrhosis patients retain effector capacity with enhanced inflammatory activity Cirrhosis reshapes the duodenal intraepithelial lymphocyte landscape Reduced frequency of CCR9+CD8{beta} IELs indicates altered gut-homing in cirrhosis

ObjectiveTo establish a fetal lamb model of complex gastroschisis and characterize the impact on the intestines over time. Summary Background DataGastroschisis is a congenital abdominal wall defect and in its complex form is associated with serious morbidity. Robust large-animal models may help understanding are lacking. MethodsAt gestational day 75, gastroschisis was induced by creating a 1-cm abdominal wall defect reinforced by a silicone ring. Fetuses were assessed either at term or at mid-gestation (13-21 days post-induction). The primary outcome was complex gastroschisis occurrence, defined by bowel stenosis, atresia, volvulus, perforation or necrosis; otherwise classified as simple. At mid-gestation, occurrence was compared between early (13-16 days) and late (17-21 days) intervals. Secondary outcomes included prenatal ultrasound findings, in vivo bowel motility and morphology, ex-vivo bowel contractility, amniotic fluid composition, and histology across complex, simple, and normal groups. ResultsGastroschisis was induced in 32 fetuses. At term (n=14), all survivors (7/14; 50%) had complex gastroschisis, with impaired bowel motility, altered enteric neural contractile responses and smooth muscle remodeling. At mid-gestation (n=18), complex gastroschisis occurred more frequently in the late than in the early group (71% vs. 11%; p=0.035). Mid-gestation gastroschisis fetuses showed greater intra-abdominal bowel dilatation on ultrasound and higher amniotic fluid digestive enzyme levels compared with non-operated littermates, with the greatest dilation observed in complex gastroschisis. ConclusionsThis model consistently reproduces complex gastroschisis in term survivors. After induction, complex gastroschisis occurrence increases with disease duration and is accompanied by structural and functional bowel changes.

BackgroundEmerging evidence suggests that the oral microbiome may contribute to aberrant gut immune responses in Inflammatory Bowel Disease (IBD). MethodsWe performed a comprehensive, harmonised analysis of aggregated oral microbiome 16S rRNA datasets across multiple cohorts. Data were processed using a unified bioinformatics pipeline including DADA2 for taxonomic assignment, PICRUSt2 for functional prediction, MaAsLin2 for multivariable modelling, and machine learning. ResultsAcross 25 studies (n = 1,136 IBD; n = 759 controls), meta-analysis showed significantly reduced oral microbial Shannon diversity in IBD (standardised mean difference -0.31, p = 0.007). Secondary bioinformatics analysis of six datasets plus in-house data confirmed this reduction (Shannon diversity; Hedges SMD = -0.372, p < 0.001), driven primarily by Crohns disease (CD). Beta diversity demonstrated global compositional shifts, with CD demonstrating greater divergence from controls than ulcerative colitis (UC). Multivariable modelling identified reproducible taxa enriched in IBD, including Corynebacterium, Serratia and Streptoccocus, while Porphyromonas and Ruminococcaceae.G1 were enriched in controls. Functional pathway prediction indicated reduced butyrate metabolism in IBD sub-types and increased aromatic amino acid and related metabolite degradation pathways. Machine learning classifiers achieved modest discrimination (mean AUC [~]0.67), supporting the potential of saliva-based microbiome profiling to study dysbiosis in IBD. ConclusionsThese findings demonstrate that the oral microbiome in IBD is characterised by reduced diversity and reproducible structural community reorganisation. Together, these data support a contributory role for the oral-gut axis in CD pathogenesis and provide a rationale for targeted mechanistic and longitudinal studies to define causal links between oral dysbiosis and intestinal inflammation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/26351936v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@57306corg.highwire.dtl.DTLVardef@2c0ef0org.highwire.dtl.DTLVardef@88b0b3org.highwire.dtl.DTLVardef@8ed62_HPS_FORMAT_FIGEXP M_FIG C_FIG

The circadian clock coordinates physiology and behavior through [~]24-h rhythms, and disruption of core clock genes has been implicated in tumorigenesis. However, the impact of Per1, a major clock gene, on colorectal tumor development remains unclear. Here, we investigated how Per1 deletion influences intestinal tumorigenesis using the ApcMin/+ mouse model and ApcMin/+Per1-/-mice generated by crossing ApcMin/+ and Per1-/- lines (C57BL/6J background). Mice were maintained under controlled light-dark conditions, and we assessed survival, intestinal polyp burden, histopathology using Swiss-roll sections, {beta}-catenin protein abundance (immunofluorescence and western blotting), Ctnnb1 mRNA expression (RT-qPCR), and crypt proliferation (5-bromo-2-deoxyuridine (BrdU) immunohistochemistry). Per1 deletion did not significantly alter overall survival in ApcMin/+ mice but increased inter-individual variability. In contrast, polyp number was markedly increased by Per1 deletion, affecting both small (<2 mm) and large ([&ge;]2 mm) polyps across intestinal segments. Histology confirmed aberrant crypt foci and polyps in both ApcMin/+ genotypes. {beta}-Catenin protein levels in the whole intestine were significantly increased by Per1 deficiency and Apc mutation (two-way ANOVA), whereas Ctnnb1 mRNA was largely unchanged across regions. BrdU-based crypt proliferation was increased by the Apc mutation but not by Per1 deletion. These results indicate that Per1 loss exacerbates intestinal polyp formation and elevates {beta}-catenin predominantly through non-transcriptional mechanisms, supporting a tumor-suppressive role of Per1 in colorectal tumorigenesis.

BackgroundAppendiceal adenocarcinoma (AA) is a rare cancer with limited treatment options. KRAS is the most commonly mutated gene in AA and a promising therapeutic target, but its preclinical and translational relevance in AA remains unclear. MethodsWe evaluated KRASG12D-specific (MRTX1133) and pan-KRAS inhibitor (RMC-6236) in KRASmut organoid and orthotopic PDX models of AA. Tumor-intrinsic and microenvironmental responses were characterized using multi-omics profiling. Clinical outcomes were also assessed in six heavily pre-treated AA patients treated with KRAS inhibitors. ResultsMRTX1133 was highly effective for KRASG12D organoids (IC50=4.1 nM); both KRASG12D and KRASG12V organoids were sensitive to RMC-6236 (IC50=4.4 nM vs 0.5 nM, respectively). In orthotopic PDX models of peritoneal carcinomatosis from AA, MRTX1133 significantly reduced tumor growth in the KRASG12D model TM00351, and RMC-6236 reduced tumor growth in KRASG12V model AAPDX-16. Pathologic evaluation showed dramatically reduced tumor cellularity, proliferation, and pERK expression as well as induction of apoptosis. Gene Sets Enrichment Analysis (GSEA) revealed significant downregulations of E2F targets (NES=-1.9, p-adj=0.06) and the newly developed RAS/ERK (NES=-2.3, p-adj=0.06) gene set, consistent with the observed decrease in cell proliferation. There was marked upregulation of EMT (NES=2.7, FDR<0.001) and TGF-{beta} signaling (NES=2.3, FDR=0.004) in remaining tumor cells, suggesting these pathways could confer resistance. scRNA-seq analysis of TME showed dramatic shifts in cancer-associated fibroblasts (CAFs), with KRAS inhibition driving a shift from normal fibroblasts to inflammatory CAFs, and upregulation of interferon alpha and gamma pathways, suggesting that KRAS inhibition can activate innate immune response in the setting of peritoneal metastases. In a cohort of 6 heavily pre-treated patients with AA treated with KRAS inhibitors (1 G12D, 3 G12C, 2 pan-KRAS), all had biochemical response based on CEA/Ca19-9 or ctDNA and clinical benefit by RECIST criteria (1 CR, 1 PR, 4 SD). ConclusionsWhile effective suppression of RAS/ERK signaling by KRAS inhibitors reduces tumor growth, adaptive activation of EMT and TGF-{beta} pathways may mediate resistance in KRASmut AA. Additionally, KRAS inhibition remodels TME and may enhance innate immune signaling. These findings support continued clinical development of KRAS inhibitors in AA and provide a rationale for combination strategies targeting resistance pathways and stromal remodeling.

BackgroundFibrosis and tumor innervation are two features of the tumor microenvironment (TME) that contribute directly to the lethality of pancreatic ductal adenocarcinoma (PDAC), but their potential interactions have not been explored. Moreover, although it is known that activated Schwann cells (SCs) stimulate cancer cell invasion, it remains unclear how SCs are activated. ObjectiveWe determined how SCs are activated in the pancreatic fibrotic microenvironment. DesignThe correlation between physical features of the microenvironment and SC activation was assessed in human patient samples and in mice by SC c-Jun phosphorylation monitoring, atomic force microscopy and multiphoton live imaging. Several in vitro models in which forces were applied to SCs expressing a reporter for c-Jun phosphorylation and RNA-Seq analysis were used to decipher the cellular and molecular mechanisms of SC activation. ResultsNerves surrounded by stiff stroma present higher SC activation. Intravital imaging shows a matrix dependent SC activation. Mechanical forces on SCs induce c-Jun phosphorylation in SCs in a non-canonical manner that involves a nuclear sensing machinery with the proinflammatory enzyme Phospholipase A2. ConclusionFibrosis enhances the protumorigenic impact of innervation by activating SCs via a mechanism in which nuclear compression triggers non-canonical activation of the AP-1 transcription factor complex. Pancreatic fibrosis alone, without cancer cells, is sufficient to activate SCs, suggesting this mechanism may be common across non-malignant pancreatic diseases. Notably, SCs are more sensitive to mechanical activation than PDAC cells. These findings reveal TME interactions that may guide future microenvironment-targeted PDAC therapies. What is already known on this topicThe pancreatic cancer tumor microenvironment is highly innervated and fibrotic, two components of the tumor microenvironment that regulate tumorigenesis. How they impact each other is unknown. Schwann cells have emerged as a significant protumorigenic player, but the triggers of Schwann cell activation remain undefined. What this study addsWe establish that fibrosis induces Schwann cell activation and characterize the mechanism by which it occurs. We uncovered a mechanical mode of action that deforms nuclear membrane and activates c-Jun in Schwann cells, which contradicts the traditional view of c-Jun activation through a stimulus detected at the plasma membrane. How this study might affect research, practice or policyThis study provides a better understanding of the biology of pancreatic ductal adenocarcinoma and supports the development of novel precision therapies that target the fibrotic microenvironment to impact the protumorigenic effect of tumor innervation.

Background & AimsCeliac disease is a wheat-induced immune-mediated enteropathy. Intestinal organoid models for adult stem cell-based celiac disease exist, but planar intestinal models derived from celiac disease patients that would allow direct assessment from both sides of the epithelium have been lacking. We aimed to bridge this gap by setting up a two-dimensional in vitro model based on small intestinal epithelial cells (SIECs) derived from induced pluripotent stem cells (iPSC) from celiac disease patients. MethodsIPSCs from celiac disease and control patients were sequentially differentiated towards SIECs. The models applicability was tested under cytokine stimuli. ResultsCeliac disease and control patient iPSCs matured similarly towards SIECs. However, they had inherent gene expression differences in inflammation- and immune-related genes, such as IRF1 and HLA-DRB1. Both iPSC-SIECs responded in a SIEC-specific manner to the cytokine stimulation. The response in celiac disease iPSC-SIECs was attenuated compared with that of control iPSC-SIECs. ConclusionsThe data confirm that iPSC-derived SIECs represent an appropriate platform for studying inflammation-associated enteropathies, such as celiac disease, but also suggest that there might be inherent patient-specific or cell type-specific differences in the responses.