To investigate the effect and mechanism of metformin on intestinal epithelial barrier injury in ulcerative colitis. A cell model of colitis was established by co-culture of human colon cancer cell line Caco-2 and human monocyte cell line THP-1. The colitis model cells were treated with metformin at concentration of for Flow cytometry was used to detect Caco-2 cell apoptosis, and Western blotting was used to detect the protein expression of tight junction proteins and endoplasmic reticulum stress-related proteins. After metformin treatment, the apoptosis rate of Caco-2 cells was decreased from (14.22±2.34)% to 0.61)% (=3.119, <0.05), and the expression levels of tight junction protein-1 and claudin-1 increased (=5.172 and 3.546, both <0.05). In addition, the expression levels of endoplasmic reticulum-related proteins glucose regulated protein (GRP) 78, C/EBP homologous protein (CHOP) and caspase-12, as well as the phosphorylation level of PRKR-like endoplasmic reticulum kinase (PERK) and eukaryotic translation initiation factor 2α (eIF2α) decreased (all <0.05). Metformin may alleviate the intestinal epithelial barrier damage in colitis by reducing intestinal epithelial cell apoptosis and increasing the expression of tight junction proteins, which may be associated with the inhibition of endoplasmic reticulum stress-induced apoptotic pathway.
Apoptosis ; Caco-2 Cells ; Colitis, Ulcerative ; Endoplasmic Reticulum Stress ; Humans ; Metformin/pharmacology*

Background::Scleroderma is characterized by inflammation and fibrosis, predominantly occurring in the skin and extending to various parts of the body. The pathophysiology of scleroderma is multifaceted, with the current understanding including endothelial damage, inflammatory cell infiltration, and fibroblast activation in its progression. Nonetheless, the mechanism of cellular interactions and the precise spatial distribution of these cellular events within the fibrotic tissues remain elusive, highlighting a critical gap in our comprehensive understanding of scleroderma’s pathogenesis.Methods::In this study, we administered bleomycin intradermally to the dorsal skin of four individual murine models. Subsequently, skin tissues were harvested at predetermined intervals for comprehensive spatial transcriptomic analysis to determine the spatial dynamics influencing scleroderma pathogenesis. To validate the possible results from bioinformatic analysis, further in vitro and in vivo experiments were conducted. Results::Analysis of the spatial transcriptome revealed significant alterations in cell clusters during the progression of scleroderma. Gene Ontology analysis identified disruptions in lipid metabolism as the disease advanced. Pseudotime analysis provided evidence for a phenotypic transition from adipocytes to fibroblasts. In vitro studies demonstrated increased expression of Col1a1 and α-SMA as the disease progressed. These fibroblasts have been identified as key contributors to the increasing inflammation. Co-culturing TGF-β induced adipocytes with RAW264.7 cells resulted in overexpression of pro-inflammatory cytokines in the RAW264.7 cells. Both in vitro and in vivo experiments confirmed adipocyte loss and fibroblast formation, with transformed fibroblasts showing pronounced pro-inflammatory characteristics, highlighting their crucial role in the disease mechanism. Conclusions::Our study showed the spatial distribution and dynamic alterations of various cell types during scleroderma progression. Crucially, we identified the transformation of adipocytes into fibroblasts as a key factor promoting disease advancement. These emergent fibroblasts intensify inflammation, indicating that research on these cell clusters could reveal key scleroderma mechanisms and guide future therapies.