Cellular and Molecular Gastroenterology and Hepatology

ABSTACTGalectin-8 is a lectin that binds N-acetyllactosamine moieties with preference towards those with acidic, terminal modifications (-O-sialyated, 3-O-sulfated). As CD44-variants (CD44v) are biomarkers of metaplasia and cancer, a hyaluronic acid receptor that modulates STAT3 signaling, and specifically expresses 3-Sialyl-LeA/X glycotopes, we asked whether galectin-8 might play a role in gastric metaplasia. Using a synchronous, chemically induced murine model that produces gastric spasmolytic polypeptide expressing metaplasia (SPEM), we compared Lgals8-/- mice to congenic wild-type C57BL/6J mice. We found that galectin-8 was necessary for membrane localization of CD44v on SPEM cells at the base of the glands, suggesting a physical interaction between galectin-8 and CD44v. Metaplastic glands from Lgals8-/- mice had an increase in nuclear pSTAT3 compared to C57BL/6J mice, suggesting that galectin-8 restrains CD44 -> STAT3 signaling. This effect was more prominent in the neck compared to the base, which has greater abundance of CD44v after injury in Lgals8-/- mice. Derepression of STAT3 signaling may explain why low galectin-8 levels is associated with a worse prognosis in gastric cancer.

The murine intestine reactivates developmental gene programs following various forms of damage in vivo and in vitro; however, injury response mechanisms used by the human intestine remain unclear. Using adult human small intestinal epithelium-only organoids ("enteroids"), we characterized the early response to eight injury conditions and injury-associated signaling pathways (P53, PGE2, YAP, TGFB) to interrogate whether human developmental genes were activated. P53 activation and decreased proliferation were common features across treatments. Most (7/8) injuries did not activate human development genes. Butyrate is a notable exception given it inhibited P53 and promoted a human developmental transcriptional signature. We observe that P53 induces a human adult gene signature while TGFB and YAP promote a developmental signature. Together our data characterizes various transcriptional responses to injury, supports injury-associated signaling pathways as regulators of human adult and developmental genes, and highlights how our data can be mined to predict injury-specific interventions for epithelial protection.

Immortalized cell lines are widely used in biological research despite their known differences from their tissues and cell types of origin. Such cell lines are especially popular for testing hypotheses regarding the activity of cis-regulatory elements (CREs) that regulate gene expression. Previous investigations of blood and skin cell lines revealed many differences between the transcriptional regulatory networks of the cell lines and the associated primary cells. Similar comparisons for other tissues have been limited. Here, we used ATAC-seq to profile CREs in four immortalized liver cell lines and found many differences between each cell lines CREs and primary liver tissue, including differences in the transcription factors that are likely to bind them and differences in the genes that they are likely to regulate. Modifying cell culture conditions based on recommendations in the literature did not improve the similarity with primary liver tissue. Our results suggest that differences between the transcriptional regulatory networks in cell lines and primary tissue should be considered when designing and interpreting cell line experiments.

The expression and secretion of sulfated colonic-type mucins is a feature of high-risk metaplasias of the gastrointestinal foregut (Barretts esophagus, type III intestinal metaplasia of the stomach, and pancreatic intraepithelial neoplasia). Galectin-3 is a lectin that preferentially associates with galactose modified by a 3-O-sulfate relative to its unmodified counterparts and is upregulated as the tissue transitions to high-risk metaplasia, dysplasia, and cancer. Since both galectin-3 and sulfated glycotopes are aberrantly and concurrently overexpressed in high-risk premalignant and malignant tissue transformations, we sought to investigate the role of galectin-3 in the metaplastic reaction. We found that injury induces the expression of Lgals3 at the RNA and protein levels. Unlike cancer cell lines, we show that in vivo galectin-3 colocalized with sulfomucins in zymogenic granules of the gastric chief cell. Utilizing a synchronous, chemically-induced murine model that produces spasmolytic polypeptide expressing metaplasia, we found that galectin-3 facilitates cathartocytosis of the vesicles it resides in, but not organelles lacking LGALS3. Inhibition of cellular downscaling resulted in delayed expression of the metaplastic transcription factor Sox9 as well as proliferation. Here, we present a new role for galectin-3 in promoting the transition from normal, homeostatic tissue to metaplasia and our data suggest that cathartocytosis represents an unconventional secretory pathway for galectin-3, which has been a matter of controversy as galectins are not secreted via canonical pathways.

An acetaminophen (APAP) overdose is the leading cause of drug-induced hepatotoxicity and acute liver failure (ALF) in the United States. While N-acetylcysteine (NAC), is highly effective when administered early after an overdose, its efficacy decreases with delayed administration. Since most patients present late to the clinic, there is an urgent need for novel late-acting therapeutic options to prevent progression to ALF. We previously demonstrated the benefit of delayed activation of the Adenosine A2B Receptor (A2BAR) in attenuating APAP-induced hepatotoxicity and this study focuses on its effects on liver recovery after injury. Fasted male C57BL/6J mice were treated with 300 mg/kg APAP, followed by activation of A2BAR 6 or 9 h later and sacrifice 24, 48 or 72 h post-APAP with evaluation of liver injury, the innate immune response and liver regeneration. Delayed activation of A2BAR significantly enhanced liver recovery, with accelerated repopulation of the liver by Kupffer cells, increased macrophage migration to the necrotic areas and their faster resolution. A2BAR activation also upregulated lipid metabolism related genes in non-parenchymal cells and cell proliferation and metabolism genes in hepatocytes. Remarkably, genes such as Cidec and Plin2, crucial for lipid droplet formation, were upregulated, indicating that A2ABR activation enhances lipid metabolism which plays a key role in providing energy for liver regeneration. Overall, these findings highlight the potential of A2BAR activation not only in protecting against liver injury, but also in promoting and accelerating liver regeneration by modulating the innate immune responses and metabolic pathways.

Hirschsprung disease (HSCR) is a severe birth defect where ganglia of the enteric nervous system (ENS) are missing from distal bowel. The aganglionic segment is also characterized by increased epithelial permeability and pro-inflammatory immune activation. These problems may sequentially lead to translocation of gut microbes into the colon wall and systemic circulation, resulting in enterocolitis and sepsis. Current HSCR treatment via surgical resection of the aganglionic segment is lifesaving but not curative, often leaving patients with persistent gastrointestinal complications including recurrent risk of enterocolitis. As alternative, we are developing a regenerative medicine strategy based on in situ stimulation of tissue-resident ENS progenitors via rectal administration of the neurotrophic factor GDNF. Here, we report that GDNF-based therapy has pleiotropic gastrointestinal effects in a mouse model of short-segment HSCR, beyond its role in ENS regeneration. Interestingly, we found that these protective effects are not restricted to the aganglionic distal colon, also positively impacting the ENS-containing proximal colon. GDNF treatment reduces bacterial translocation both locally and in peripheral organs, and this is associated with recovery of the key epithelial junction proteins CLDN3, ZO1 and DSG2. Furthermore, multiparameter flow cytometry-based analysis of 55 lymphoid and 17 myeloid cell subtypes revealed that GDNF treatment has global anti-inflammatory effects, preferentially affecting innate over adaptive immunity. Overall, these findings highlight a critical role for GDNF treatment in reestablishing proper epithelial and immune cell homeostasis, offering promising therapeutic avenues not only for HSCR but also potentially for other intestinal disorders with overlapping pathophysiology.

Background & Aims Dynamic cell cycle control is critical for intestinal crypt maintenance and injury responses, yet genetic regulators driving these changes remain poorly defined. As reserve intestinal stem cells (rISCs) are often considered to be slowly-cycling and can resist replication-dependent injury, factors that restrain proliferation may confer cytoprotection. Here, we define SOX9 as a regulator of intestinal stem cell (ISC) cycling and injury resistance. Methods Primary human ISCs were engineered to tune SOX9 levels, visualize cell cycle state, and manipulate cell cycle regulators. Using this system, we tested how SOX9 dosage impacts stemness, differentiation, proliferative recovery after SOX9 washout, and survival after 5-FU-mediated injury. Transcriptional analyses identified candidate links between SOX9 levels and cell cycle control, which were functionally tested using inducible INK4A (CDKN2A) and Cyclin D2 (CCND2) ISC lines. Results SOX9 induction lengthens the cell cycle in a dose-dependent manner largely by elongating G1 phase through the INK4A-Rb pathway. The effects of high SOX9 levels repressing proliferation and stem cell activity are reversible. SOX9 induction protects against 5-FU toxicity. This protection is mimicked by INK4A overexpression or pharmacological G1 phase arrest and repressed by CCND2 induction. Conclusions These findings identify SOX9-mediated G1 elongation as a reversible cytoprotective program that confers key functional properties associated with rISCs: proliferative restraint, retained stem cell potential, and resistance to replication-dependent injury. This positions G1 length as a potential determinant of which crypt cells survive injury to act as reserve stem cells.

Inflammatory bowel disease (IBD) often involves disrupted intestinal epithelial barrier, but therapies specifically targeting this barrier are limited. We found that downregulated AUF1 (HNRNPD) contributes to defective barrier integrity in ulcerative colitis (UC). Compared to controls, its expression level was decreased and inversely correlated with clinical severity. Knocking down AUF1 in human and mouse colonic organoids led to impaired barrier function, with reduced Occludin and upregulated Claudin-2, mimicking characteristic IBD-associated mucosal alterations. Distinct RNA-binding activity of AUF1 protein isoforms contributed to these changes: p37 stabilized Occludin mRNA and blocked microRNA-122/Ago2-mediated repression, whereas p40 promoted Claudin-2 mRNA degradation via ubiquitin-proteasome pathway. Restoring AUF1 expression in organoids enhanced epithelial properties and, when transplanted into mice with established colitis, accelerated mucosal healing and epithelial regeneration in recipient mice and decreased fibrosis. Our study unravelled a post-transcriptional mechanism important for intestinal homeostasis and demonstrated a concept of using engineered organoids for treating IBD.

Gastric cancer is the fifth leading cause of cancer-related mortality in humans globally and remains a clinical challenge with limited treatment options and poor survival. Dogs develop spontaneous gastric cancer that parallels the clinical presentation and histology of human disease, supporting their value as a comparative oncology model. Here we present a comprehensive transcriptomic characterization of canine gastric cancer through single-nucleus RNA-sequencing, bulk RNA-sequencing, and Visium HD 3' spatial transcriptomics of treatment-naive tumor and normal stomach tissues from Belgian Tervuren and Belgian Sheepdogs. Across 107,085 nuclei, we identified 44 distinct cell populations, including tumor-enriched states as well as profound depletion of the normal parietal and chief cell gastric lineages. Cell-cell communication analysis revealed enhanced epithelial-fibroblast crosstalk driving epithelial-mesenchymal transition. Bulk RNA-sequencing further identified enrichment of signaling pathways implicated in H. pylori associated human gastric carcinogenesis, including Hippo, PI3K-Akt, and Wnt. Notably, we observed cell-type-specific altered expression of KLHL29, PDZRN3, and PLAU, which are among our previously identified canine gastric cancer susceptibility genes, linking germline risk to specific tumor cellular contexts. These data establish the first transcriptomic atlas of canine gastric cancer and demonstrate substantial molecular homology between canine and human disease.

Nuclear bile acid (BA) signaling plays a central role in liver homeostasis and represents a major therapeutic axis in fibrotic liver diseases. The farnesoid X receptor (FXR), a master nuclear effector of BA signaling, is expressed in several liver-resident cell types, suggesting that it may regulate distinct biological programs beyond the hepatocyte (HC) compartment. Using complementary pharmacological, genetic, and computational approaches across in vitro, ex vivo, and in vivo models of mouse and human origin, we investigated the role of hepatic stellate cell (HSC) FXR (FXRHSC) in both unchallenged and injured livers, which has remained controversial. FXR is robustly expressed in both HCs and HSCs with distinct isoform distributions, and these isoforms exhibited differential capacities to activate gene expression in an HSC context. We found that the potent selective FXR agonist tropifexor triggers a transcriptional program reminiscent of that observed after partial hepatectomy and associated with HC proliferation. This cell cycle-related response was also observed in HSCs and did not require intestinal FXR expression. An HSC-specific response to tropifexor was observed for several genes, including members of the glutathione-S-transferase (GST) family or Scube1. FXRHSC was sufficient to observe the anti-fibrotic effects of tropifexor in precision-cut liver slices, an ex-vivo model of fibrosis. Finally, we identified the regulation of the chemerin-encoding gene Rarres2 as a relevant example of FXRHSC-dependent control of hepatic intercellular communication. Together, these findings identify FXRHSC as an important contributor to hepatic adaptation and therapeutic response to BA analogs and confirmed HSCs as a significant site of nuclear bile acid signaling in liver biology.

Leptin receptor (LEPR) signaling has been implicated in multiple malignancies; however, its role in gastric tumors remains poorly defined. We previously demonstrated that mice with gastrointestinal epithelial cell-specific deletion of suppressor of cytokine signaling 3 (SOCS3 cKO), a negative feedback regulator of LEPR signaling, develop gastric tumors due to aberrant leptin production and LEPR activation. Here, we demonstrate that concurrent deletion of both Socs3 and Lepr (double knockout; DKO) under the same promoter substantially suppresses gastric tumorigenesis and markedly prolonged survival. Whereas SOCS3 cKO mice exhibited early stromal activation, increased TGF-{beta}1 production, accumulation of cancer-associated fibroblasts (CAFs) and collagen deposition, these tumor-promoting alterations were substantially attenuated in DKO mice. Additionally, DKO mice showed reduced inflammatory cytokine and chemokine signaling, decreased the accumulation of Gr-1+CD11b+ myeloid-derived suppressor cells, and reduced LEPR and TGF-{beta} signaling. Analysis of The Cancer Genome Atlas stomach adenocarcinoma cohort revealed high LEPR expression in the chromosomal instability and genomically stable subtypes, correlating with poor prognosis. Moreover, LEPR expression was mutually exclusive with CLDN18 and ERBB2, two major therapeutic biomarkers, and positively correlated with a CAF-related transcriptional signature. Our findings identify LEPR signaling in epithelial cells as a key driver of gastric tumorigenesis through promotion of stromal activation and tumor microenvironment development. They further highlight LEPR as a promising therapeutic target for patients with gastric cancer who are unlikely to benefit from current ERBB2/HER2- or CLDN18-directed therapies.

Pancreatic ductal adenocarcinoma (PDAC) is currently the third leading cause of cancer-related deaths in the United States. Intraductal papillary mucinous neoplasms (IPMNs) are neoplastic lesions of ductal origin that seed 10-25% of PDAC. There are currently no markers that distinguish between IPMN that will remain benign and those that will progress to cancer. A heterogenous population of secretory cells, including chemosensory tuft cells and hormone-expressing enteroendocrine cells (EECs), form during metaplasia and neoplastic progression in the pancreas, but the relevance of these populations as it relates to IPMN progression is not well characterized. Here, we performed spatial transcriptomics as well as multiplex immunostaining and spatial statistics on surgically resected IPMN from 60 patients to characterize these populations in all subtypes (gastric foveolar, intestinal, pancreatobiliary) and grades (low-grade, high-grade, invasive). We found that POU2F3+ tuft-like cells, CHGA+ EECs, and a subset of pancreatic endocrine cells ([a] and {gamma} cells) were present in all types of IPMN. Further, serotonin-expressing enterochromaffin cells made up the bulk of EECs in low-grade disease. Enterochromaffin, tuft-like, and glucagon-expressing alpha cells were not evenly distributed and instead were significantly enriched in a spatial manner, which is overlooked using conventional whole tissue quantification approaches. Tuft-like cell clusters were enriched with monocytes and resident memory T cells and anti-correlated to activated fibroblasts (myCAFs, iCAFs). Overall, these secretory cell clusters may reflect clonal expansion resulting in formation of distinct stromal niches with unknown consequences for disease progression.

Stomach infection with the bacterium Helicobacter pylori (Hp) can cause chronic gastric inflammation, metaplasia (transdifferentiation of mature cell types), dysplasia (abnormal cells), and finally cancer. Obesity can also increase gastric cancer risk. However, host-Hp interactions during obesity are poorly understood. Here we investigated the impact of diet-induced obesity in two mouse models of Hp-associated disease. To model chronic gastric inflammation, we used C57BL/6 mice, and to model more severe disease, we used transgenic mice in which tamoxifen induces gastric expression of a constitutively active Kras allele, leading to metaplasia. We fed mice a high-fat diet (60% kilocalories from fat) to induce obesity, or a matched control diet (10% kilocalories from fat), then infected them with Hp or mock-infected them. In mock-infected C57BL/6 mice, high-fat diet had a minimal impact on gastric pathology and gene expression. In Hp-infected C57BL/6 mice, high-fat diet increased inflammation at the junction between the glandular stomach and non-glandular forestomach, a squamous epithelium similar to the human esophagus, and increased gastric expression of the cancer-associated genes Cldn7 and Reg3g. In KRAS+ mice with or without Hp infection, the impact of diet-induced obesity was more apparent, with increased metaplasia and dysplasia (abnormal cells). As well, high-fat diet caused an expansion of metaplastic pit cells, a lineage we previously found to be associated with Hp-driven inflammation. Thus, in these mouse models, diet-induced obesity does not directly drive gastric immunopathology, but enhances the development of pre-cancerous changes under susceptible conditions. IMPORTANCEMost gastric cancers are caused by stomach infection with the bacterium Helicobacter pylori. However, most infected individuals never develop cancer. Therefore, additional risk factors must tip the balance toward gastric cancer development. Obesity, or excessive body fat accumulation that poses a risk to health, is associated with gastric cancer development. However, specific mechanisms for obesity-driven gastric cancer risk are not well defined. Here we tested the hypothesis that obesity would exacerbate Helicobacter pylori-associated disease phenotypes using two clinically relevant mouse models. In wild-type mice, obesity induced by a very high-fat diet had a minimal impact on the stomach in the absence of infection, but increased the expression of some cancer-associated genes during infection. However, in mice with genetically driven pre-cancer, diet-induced obesity exacerbated the disease pathology, especially in infected mice. Therefore, obesitys impact on gastric cancer risk may be more evident in the later stages of the disease.

Introduction: Genome-wide association studies have identified a common variant at chr19q13.33 within the FUT2 locus as a determinant of colorectal cancer (CRC) susceptibility, with each risk allele conferring an approximately 7% increase in risk (OR 1.07, P = 6.11E--10). This locus regulates expression of FUT2, a fucosyltransferase involved in 1,2- glycosylation, and has also been associated with circulating vitamin B12 (B12) concentrations in genome-widestudies. Objective: To determine whether FUT2 influences CRC-risk through effects on circulating B12 and to test causal relationships across genetic, experimental, and clinical data. Methods: We performed summary-data-based Mendelian randomisation using FUT2 eQTLs from GTEx colon tissue and genome-wide association data for plasma B12 (Generation Scotland), with mediation analysis estimating the proportion of effect mediated by B12. Causal inference was then tested in vivo using Fut2 knockout and wild-type mice exposed to azoxymethane/dextran sodium sulphate (AOM/DSS), with or without B12 supplementation. Results: Genetically predicted higher FUT2 expression was associated with lower B12 levels ( {beta} = -0.735, SE = 0.110, P = 2.63E-11) and reduced CRC-risk ({beta} = -0.256, SE = 0.058, P = 5.85 E -5). Mediation analysis suggested ~80% of the effect of FUT2 on CRC risk is mediated via B12. In mice, neither Fut2 deficiency nor B12 supplementation alone induced tumours, but both significantly increased tumour burden under chemical carcinogenic challenge, with comparable effect sizes.

Antral CCK2R+ stem cells are regulated by gastrin, but how endocrine and neural cues integrate under chronic injury remains unclear. Here we show that inducible hypogastrinemia shifts from asymmetric renewal to symmetric expansion of CCK2R+ stem cells. With carcinogenic stress, these cells acquire a cycling, injury responsive progenitor state revealed by single-cell RNA profiling. Acute gastrin loss activates a CCK2R+ nodose DMV vagal reflex that increases acetylcholine release, NGF production, cholinergic innervation, and Chrm3 expression, driving ERK and YAP signaling in CCK2R+ stem cells. Vagotomy, Trk inhibition, or Chrm3 deletion each suppressed stem cell expansion. In H. pylori and MNU injury models, hypogastrinemia amplified inflammation, dysplasia, and CCK2R+ clone expansion, whereas gastrin suppressed these responses. Human scRNA seq and spatial profiling confirmed G cell depletion and progenitor state enrichment. These findings define an endocrine neural epithelial axis in which gastrin loss boosts vagal M3R signaling to initiate antral preneoplasia, highlighting this pathway for early interception.

Defective intestinal epithelial tight junction (TJ) barrier function and endoplasmic reticulum (ER) stress are central pathological features of inflammatory bowel disease (IBD), yet the molecular mechanisms ER stress to TJ disruption remains poorly understood. Here, we investigated the role of autophagy in regulating intestinal TJ homeostasis during ER stress. ER stress was elevated in inflamed Crohns disease tissue and chronic dextran sulfate sodium (DSS) colitis. In human intestinal epithelial Caco-2 monolayers, murine colon, and human colonic explants, induction of ER stress with tunicamycin, thapsigargin, or brefeldin A disrupted TJ barrier integrity, as demonstrated by reduced transepithelial electrical resistance and increased paracellular permeability. ER stress selectively increased the pore-forming TJ protein claudin-2 and altered occludin localization without significantly affecting other claudins. Pharmacologic activation of autophagy with rapamycin attenuated ER stress, restored TJ barrier function, reduced claudin-2 accumulation, and preserved occludin localization. Conversely, CRISPR-Cas9-mediated deletion of autophagy gene ATG7 exacerbated ER stress, apoptosis, and TJ barrier dysfunction in vitro, while intestinal epithelial-specific Atg7 knockout mice exhibited enhanced ER stress-induced intestinal permeability in-vivo. Mechanistically, prolonged ER stress impaired autophagic flux through IRE1 kinase signaling, resulting in accumulation of p62 and claudin-2. Inhibition of IRE1 kinase activity restored autophagy, reduced claudin-2 levels, and preserved TJ barrier function. We further identified adaptor-associated kinase 1 (AAK1) as a downstream mediator of IRE1 signaling during ER stress, with increased AP2M1 phosphorylation and altered claudin-2 trafficking. Claudin-2 overexpression alone induced ER stress and lysosomal damage, suggesting a feed-forward mechanism amplifying epithelial injury. Finally, enteric rapamycin administration reduced ER stress and restored autophagy in murine DSS colitis. Collectively, these findings identify an IRE1-AAK1-autophagy axis as a critical regulator of intestinal TJ barrier integrity during ER stress.

Background & aimsChronic inflammation is a key driver of progression from benign steatosis to metabolic dysfunction-associated steatohepatitis (MASH) and liver fibrosis. The molecular mechanisms coupling inflammatory cytokine signaling to altered hepatocyte remodeling remain incompletely understood. Here, we report that nicotinamide N-methyltransferase (NNMT) is induced by specific inflammatory cytokines in hepatocytes and acts as a key hub to connect inflammation with fibrotic liver remodeling. Approach & resultsTranscriptomic profiling of primary human hepatocytes and human hepatoma cell lines identified NNMT as a selective downstream target of IL-1{beta} and IL-6, but not of TNF. Genetic silencing of NNMT markedly attenuated cytokine-induced inflammatory and fibrotic gene expression programs and partially reversed IL-6-mediated sensitization of IL-1{beta} responses. Integration of RNA-seq with ChIP-seq, CUT&Tag, and ATAC-seq revealed that inflammatory cytokines remodel the hepatocyte epigenome through coordinated changes in histone modifications. NNMT overexpression promoted selective remodeling of H3K4me2 chromatin landscapes, accompanied by activation of fibrosis-associated transcriptional programs. Nicotinamide supplementation partially suppressed inflammatory gene expression, supporting a role of NNMT-dependent NAD+ metabolism in this process. Importantly, cytokine-induced NNMT expression and its associated transcriptional program were conserved in primary human hepatocytes and 3D liver microtissues. ConclusionsNNMT functions as an inflammatory cytokine-inducible metabolic- epigenetic integrator that links IL-1{beta} and IL-6 signaling to chromatin remodeling and inflammatory transcriptional reprogramming in hepatocytes. These findings identify NNMT as a key regulator of inflammatory and profibrotic responses during MASLD progression and highlight NNMT as a potential therapeutic target for limiting liver inflammation and fibrosis. Impact and ImplicationsThis study identifies NNMT as a previously unrecognized metabolic-epigenetic integrator that selectively links IL-1{beta} and IL-6 signaling to chromatin remodeling and inflammatory transcriptional reprogramming in hepatocytes. Our findings establish a non-canonical mechanistic framework by which inflammatory cytokines drive profibrotic gene expression during MASLD progression through. By uncovering NNMT as a critical mediator of inflammatory-epigenetic crosstalk, this work broadens our understanding of hepatocyte-intrinsic mechanisms underlying liver fibrosis and highlights NNMT as a promising therapeutic target for preventing the transition from steatosis to progressive MASH and fibrosis. HighlightsO_LINNMT is selectively induced by IL-1{beta} and IL-6 in hepatocytes. C_LIO_LINNMT controls fibrogenic gene expression modules. C_LIO_LIIL-6 amplifies IL-1{beta} responses through an NNMT-dependent mechanism. C_LIO_LINNMT links inflammatory signaling to epigenetic remodeling in MASLD. C_LI

Colorectal cancer arises from intestinal epithelial cells and is driven by the accumulation of aberrant signaling events that disrupt intestinal stem cell (ISC) homeostasis. While stromal regulation of the ISC niche is increasingly recognized, the contribution of the underlying/adjacent smooth muscle tissue (SMT) remains poorly characterized. In particular, the potential crosstalk between normal or tumoral epithelium and the SMT is largely unexplored. Here, we investigate the ability of the SMT in modulating normal and tumorigenic epithelial biology, and the impact of the tumoral epithelium on the underlying SMT. Mechanistically, by using imaging analyses, transcriptomics, and mass spectrometry, we identify the SMT-derived factor Prostaglandin E2 (PGE2) as the key driver of epithelial dedifferentiation, promoting YAP transcriptional activation, organoid enlargement, and spheroid morphology in intestinal epithelial organoids following SMT supernatant exposure. Conversely, we show that non-invasive tumoral epithelium induces significant changes in the underlying SMT. Tumor-associated SMT shows structural remodeling, inflammation, and reduced muscle fitness. Furthermore, we detected increased prostaglandin signaling, including upregulation of PGE2 synthase Ptgs1 (COX1), in the SMT underneath the epithelial tumor. Our results reveal a communication between the tumoral epithelium and the underlying SMT prior to metastasis, which could be a facilitating step for tumoral extramural progression. Taken together, these findings highlight a novel tumor-stroma interaction.

Epithelial cells can encode prior damage into lasting epigenetic and functional states, enabling a primed response to future insults. In the pancreas, acute injury induces reversible acinar cell reprogramming toward a progenitor-like identity that persists beyond repair, supporting resilience to recurrent injury but creating a permissive state for malignant transformation. Given the central role of the tissue niche in stem cell regulation, we investigated microenvironmental adaptations that sustain this primed epithelial state. Using genetic mouse models and ex vivo organoid co-cultures, we identify a sex-specific sensory neural memory after pancreatitis that sustains long-term epithelial plasticity through a CGRP-dependent neuron-epithelial axis. We show that sex differences in acute inflammation drive neutrophil-dependent suppression of neural activation in females, decoupling neural memory from epithelial plasticity after repair. In males, neural memory promotes post-injury plasticity, revealing tissue memory as coordinated adaptation between epithelial progenitors and their niche.

Wolman disease (WD), the severe infantile form of lysosomal acid lipase deficiency, is a rare metabolic disorder caused by inactivating mutations in the LIPA gene. Although WD is characterized by profound hepatic dysfunction, experimental human systems capable of modelling multicellular liver pathology and supporting therapeutic testing remain limited. Here, we generated an isogenic human model of WD by introducing LIPA loss-of-function mutations into induced pluripotent stem cells and differentiating them into multicellular human liver organoids (HLO). LIPA-deficient HLO preserved hepatic lineage specification while recapitulating key biochemical and cellular features of WD, including loss of LIPA activity, lysosomal expansion, lipid accumulation, and activation of inflammatory and fibrogenic programs. Single-cell RNA sequencing resolved cell-type-specific disease states across hepatocyte-, stromal-, and biliary-like populations, revealing the emergence of a reactive biliary program consistent with ductular reaction, a complex tissue response associated with chronic liver injury. Importantly, this reactive biliary phenotype was supported by targeted gene-expression analysis in WD liver organoids and independently validated in liver tissue from mouse models and WD patients. Isolated LIPA-deficient cholangiocyte organoids failed to reproduce the DR-associated program, indicating that this response depends on multicellular interactions within the hepatic microenvironment rather than on biliary cell-autonomous dysfunction alone. Consistently, hepatocyte-directed AAV-mediated restoration of LIPA expression attenuated metabolic stress, inflammatory and fibrogenic programs, and suppressed ductular reaction both in organoids and in vivo. Together, these findings establish multicellular human liver organoids as a physiologically relevant platform for modelling emergent tissue-level responses in WD and for evaluating therapeutic rescue strategies in a human context.