Cellular and Molecular Gastroenterology and Hepatology最新文献

Background & aims: Insulinomas are rare pancreatic neuroendocrine neoplasms (pan-NENs) characterized by inappropriate insulin secretion. Despite advances in imaging techniques, the reliable identification of insulin-secreting lesions remains challenging. In addition, medical treatment options are limited and have seen little development in recent years, highlighting the unmet need for improved diagnostic tools and therapeutic strategies. This study aimed to identify the molecular mechanisms underlying insulin hypersecretion in insulinomas.

Methods: We established a biobank of human insulinoma surgical specimens and matched organoids. Comprehensive transcriptomic analyses-including bulk RNA sequencing, single-cell RNA sequencing, quantitative polymerase chain reaction, and immunohistochemistry-were conducted to identify genes enriched in insulin-secreting components. Functional validation was performed using MIN6 cells, a xenograft mouse model, and long-term cultured human insulinoma organoids.

Results: We identified dedicator of cytokinesis 10 (DOCK10) as a gene selectively overexpressed in insulin-secreting components of insulinomas. DOCK10 knockdown impaired glucose-stimulated insulin secretion in both mouse insulinoma cells and patient-derived organoids. Inhibition of the downstream effector Cdc42 with ML141 reduced insulin hypersecretion and improved survival in a MIN6 xenograft mouse model. These findings uncover a previously unrecognized role of the DOCK10-Cdc42 axis in regulating insulin secretion in insulinoma.

Conclusions: This study suggests that DOCK10 may serve as a diagnostic marker for insulin-secreting lesions and a potential therapeutic target in insulinoma. It provides mechanistic insights that may inform future strategies for precision diagnostics and treatment of functional pancreatic neuroendocrine tumors.

Background & aims: Stress granules (SGs) represent membrane-free cytoplasmic structures rapidly aggregating during cellular stress responses arguably useful as markers of molecular inflammation. To provide an automated, reproducible, and unbiased analytic workflow, we used the open-source software CellProfiler to quantify SGs in distinct cell types in inflammatory bowel disease.

Methods: The EpiCellProfiler (ECP) and PropiCellProfiler (PCP) pipelines enable segmentation within intestinal epithelial cells and lamina propria cells, respectively. The SG marker Ras GTPase-activating protein-binding protein 1 (G3BP1) was quantified for fluorescence intensity, granule size, and morphology on tissue sections of patients with ulcerative colitis (UC) and Crohn's disease (CD) in deep remission.

Results: Both pipelines detected elevated G3BP1 fluorescence intensities in inactive UC and CD. Additionally, SGs spot counts and spot sizes were increased in CD and UC compared with controls. The distribution of G3BP1 was homogenous in intestinal epithelial cells, without SG typical aggregations. In UC, PCP analysis revealed nuclear morphology alterations in terms of size, regularity, and compactness.

Conclusions: Herein, we provide a powerful, reproducible, versatile and open-source software tool to quantify remnant molecular inflammation in patients with CD and UC, enabling research to openly share, reproduce and compare results within the field of quantitative image analysis. Our pipeline separates and distinguishes between epithelial and lamina propria events and provides insights into the spatial distribution and dynamics of SGs, revealing their homogeneous distribution and persistent accumulation in patients with CD and UC, notably in such without clinical, endoscopic, biochemical and histological disease activity. The sensitivity of the pipelines allows detection of subtle morphologic alterations that warrant further investigation, as does the usage of G3BP1 as an inflammatory bowel disease stress marker.

Background & aims: Fibrostenosis is a major complication of Crohn's disease (CD) characterized by intestinal remodeling and excessive extracellular matrix (ECM) deposition. A prominent feature is bowel wall muscularization, involving expansion of submucosal myoid cells and muscularis propria smooth muscle cell (SMC) hyperplasia. However, the cellular identity and molecular mechanisms underlying submucosal myoid cell hyperplasia remain poorly characterized.

Methods: Preoperative intestinal ultrasound from 117 patients with CD was retrospectively reviewed, and ileal tissues from 25 normal, 35 nonstenotic CD, and 44 stenotic CD cases were analyzed histologically. High-resolution spatial transcriptomics was applied to 1 nonfibrotic and 1 fibrostenotic ileal specimen with marked submucosal myoid cell expansion. Findings were validated using public single-cell RNA sequencing datasets (n = 158), immunofluorescence, primary pericyte cultures, and quantitative polymerase chain reaction.

Results: Submucosal myoid cells were predominantly identified as high ECM-producing myofibroblasts, possibly representing the dominant stromal population expanded in fibrotic submucosa. Spatial and pseudotemporal analyses demonstrated their origin from muscularis mucosae and submucosal vascular SMCs. Additionally, pericytes underwent significant expansion and transcriptional reprogramming toward a myofibroblast-like phenotype. Fibroblast sub-clustering revealed spatial heterogeneity, with FAP⁺ fibroblasts enriched specifically in fibrotic regions. Inflammatory monocytes colocalized with stromal cells, exhibiting robust predicted ligand-receptor interactions indicative of immune-stromal crosstalk.

Conclusions: This case-level, high-resolution spatial analysis delineates a spatially organized fibrotic niche within a CD stricture, composed of distinct stromal and immune populations. We define the identity and origins of profibrotic myofibroblasts and characterize pericyte-to-myofibroblast reprogramming, thereby highlighting specific cell subtypes as prime therapeutic targets for antifibrotic strategies.