Background & Aims Functional constipation is closely associated with impaired gastrointestinal motility and mitochondrial dysfunction. Electroacupuncture has shown therapeutic potential in functional constipation; however, the underlying cellular and molecular mechanisms remain incompletely understood. We investigated whether electroacupuncture alleviates functional constipation through the regulation of heat shock factor 1–dependent mitochondrial unfolded protein response signaling in colonic smooth muscle cells. Methods A loperamide-induced functional constipation mouse model was established in male mice and treated with electroacupuncture at Tianshu and Shangjuxu. Gastrointestinal motility and neurohumoral mediators were evaluated. Single-cell RNA sequencing was performed to identify electroacupuncture-responsive colonic cell populations and molecular pathways. Mitochondrial ultrastructure and function, as well as heat shock factor 1–dependent mitochondrial unfolded protein response signaling, were assessed using transmission electron microscopy, immunofluorescence staining, flow cytometry, colorimetric assays, quantitative real-time polymerase chain reaction, and Western blotting. Adeno-associated virus–based heat shock factor 1 knockdown and overexpression under a smooth muscle–enriched promoter were further used for mechanistic validation. Results Electroacupuncture markedly improved gastrointestinal motility and partially restored neurohumoral homeostasis in mice with functional constipation. Single-cell RNA sequencing identified colonic smooth muscle cells as a principal electroacupuncture-responsive cell population and revealed transcriptional remodeling associated with mitochondrial homeostasis and contractile function. Electroacupuncture attenuated mitochondrial ultrastructural damage, restored mitochondrial membrane potential and adenosine triphosphate production, reduced mitochondrial reactive oxygen species accumulation, and enhanced mitochondrial respiratory chain complexes activities in colonic smooth muscle cells. These effects were accompanied by increased nuclear accumulation of heat shock factor 1 and upregulation of mitochondrial unfolded protein response–associated proteins, including heat shock protein 60, mitochondrial heat shock protein 70, and Lon peptidase 1. Heat shock factor 1 knockdown aggravated mitochondrial dysfunction and constipation-associated phenotypes, whereas heat shock factor 1 overexpression largely mimicked the therapeutic effects of electroacupuncture. Conclusions Electroacupuncture alleviated functional constipation, at least in part, through activation of heat shock factor 1–dependent mitochondrial unfolded protein response signaling and restoration of mitochondrial homeostasis in colonic smooth muscle cells.
BACKGROUND & AIMS: The Wnt-6-catenin and Yes-associated protein pathways cooperatively drive gastrointestinal tumor progression. BCL2L1, a Yes-associated protein target gene, encodes the anti-apoptotic isoform B-cell lymphoma-extra-large, which is highly expressed in multiple cancers, but its role in gastric cancer remains unclear. \METHODS: We generated Mist1-CreERT; Apcflox/flox and bclxlflox/flox mice to study gastric tumorigenesis with or without B-cell lymphoma-extra-large. Gastric organoids and xenografts were used to assess proliferation and downstream signaling, and findings were validated in human gastric cancer tissues and databases. RESULTS: Deletion of B-cell lymphoma-extra-large significantly reduced tumor growth and proliferation in Apc-deficient tumors, organoids, and xenografts. Nuclear 6-catenin and Wnt target gene expression were attenuated, partly through derepression of Hnf4a and Pparg, indicating that B-cell lymphoma-extra-large promotes Wnt signaling. Concurrently, downregulation of Hnf4a and Pparg contributes to the inhibition of multiple metabolic pathways. In human gastric cancer, high BCL2L1 expression correlated with elevated Wnt target genes and poor prognosis, whereas PPARG expression inversely correlated with BCL2L1 and associated with favorable outcomes. Epidemiologic analysis suggested that pioglitazone, a peroxisome proliferator-activated receptor gamma agonist, reduced gastric cancer incidence in diabetic patients. CONCLUSIONS: B-cell lymphoma-extra-large promotes gastric tumorigenesis through dual mechanisms-enhancing Wnt signaling and suppressing peroxisome proliferator-activated receptor gamma-and highlight B-cell lymphoma-extra-large as a potential therapeutic target while suggesting peroxisome proliferator-activated receptor gamma activation may be protective. (Cell Mol Gastroenterol Hepatol 2027;21:101880; https:// doi.org/10.1016/j.jcmgh.2026.101880)
Background & Aims The incidence of gastric cardia adenocarcinoma has increased with the increasing prevalence of metabolic syndrome. Peroxisome proliferator–activated receptor-δ emerged as a key target in metabolic syndrome and carcinogenesis. We aimed to elucidate its role in gastric cardia adenocarcinoma progression. Methods Male keratin 19 promoter–Wnt1/cyclooxygenase-2 and microsomal prostaglandin E synthase-1 overexpressing mice were fed a control or high-fat diet with or without the peroxisome proliferator–activated receptor-δ agonist GW-501516 or the peroxisome proliferator–activated receptor-δ antagonist GSK-3787. The involvement of Nrf2 in the peroxisome proliferator–activated receptor-δ–regulated, metabolism–driven tumorigenesis was examined by comparing wild-type and nuclear factor erythroid 2–related factor 2–deficient conditions. Results In high-fat diet + GSK-3787–treated keratin 19 promoter–Wnt1/cyclooxygenase-2 and microsomal prostaglandin E synthase-1 overexpressing mice with metabolic endotoxemia, granular–nodular tumors at the squamocolumnar junction were greater than those in the other groups. Intratumor expression of the NAD(P)H quinone dehydrogenase 1 and glutathione peroxidase 4 proteins increased and the plasma levels of dysbiosis-related metabolites for tumor energy metabolism increased. In high-fat diet + GSK-3787–treated nuclear factor erythroid 2–related factor 2–deficient mice, tumors shrank with decreases in NAD(P)H quinone dehydrogenase 1 and glutathione peroxidase 4 protein expression and increases in the malondialdehyde level and oxidized glutathione/reduced glutathione ratio, and the plasma levels of metabolites for energy metabolism and ferroptosis resistance decreased. The suppression of peroxisome proliferator–activated receptor-δ signaling in AGS cells treated with GSK-3787 or a small interfering RNA inhibited ferroptosis by increasing solute carrier family 7 member 11 expression and activating nuclear factor erythroid 2–related factor 2 signaling. Transfection with Nuclear Factor Erythroid 2–Related Factor 2 small interfering RNA decreased the GSK-3787–induced upregulation of solute carrier family 7 member 11, and Nuclear Factor Erythroid 2–Related Factor 2 directly regulates SLC7A11 transcription by binding to its promoter. Conclusions Cotreatment with a high-fat diet and GSK-3787 may promote squamocolumnar junction tumor progression by suppressing ferroptosis through intratumoral nuclear factor erythroid 2–related factor 2 signaling and dysbiosis–related metabolites, indicating a negative role of peroxisome proliferator–activated receptor-δ signaling on metabolic syndrome–related squamocolumnar junction tumorigenesis.
Background & Aims Killer cell activating receptor–associated protein, also known as TYRO protein tyrosine kinase binding protein, has been reported to participate in the regulation of autoimmunity and inflammation. However, the underlying mechanisms involved in intestinal mucosal inflammation in ulcerative colitis remain obscure. Methods We analyzed killer cell activating receptor–associated protein expression in colon tissues from patients with ulcerative colitis and established dextran sulfate sodium–induced colitis models in killer cell activating receptor–associated protein knockout mice to determine the potential role of killer cell activating receptor–associated protein in the induction of mucosal inflammation. To clarify the immunoregulation of neutrophils on intestinal epithelial barrier function, we cocultured neutrophils isolated from killer cell activating receptor–associated protein knockout or wild-type mice with intestinal epithelial cells. Additionally, we profiled neutrophil tryptophan metabolites using targeted metabolomics. Results Our data demonstrated that killer cell activating receptor–associated protein was highly expressed in the intestinal mucosal tissue and peripheral blood neutrophils of patients with active ulcerative colitis, particularly in neutrophils. Inhibition of killer cell activating receptor–associated protein promoted anti-inflammatory immune responses in neutrophils in vitro, showing a significant decrease in the expression of proinflammatory cytokines, including interleukin6, tumor necrosis factor-α, and interleukin1β. Consistently, killer cell activating receptor–associated protein deficiency alleviated dextran sulfate sodium–induced colitis in mice and improved intestinal mucosal barrier integrity via the aryl hydrocarbon receptor–interleukin22 pathway in neutrophils. Mechanistically, killer cell activating receptor–associated protein deficiency enhanced the nuclear translocation of aryl hydrocarbon receptor through the indoleamine 2,3-dioxygenase 1–kynurenine pathway in neutrophils. Notably, administration of killer cell activating receptor–associated protein knockout neutrophils alleviated mucosal inflammation in dextran sulfate sodium–induced colitis mice. Conclusions Overall, our study highlights the critical role of killer cell activating receptor–associated protein in mucosal inflammation in ulcerative colitis by promoting neutrophil proinflammatory immune responses and disrupting the intestinal mucosal barrier integrity, suggesting that targeting killer cell activating receptor–associated protein in neutrophils may represent a novel therapeutic approach for ulcerative colitis.
Background and Aims The tumor microenvironment drives many malignant features of pancreatic ductal adenocarcinoma (PDAC). The fibroblasts within pancreatic tumors promote tissue remodeling, immune suppression, and resistance to therapy. However, the interactions between stromal populations and pancreatic cancer cells are less understood in the liver, the most frequent site of PDAC metastasis. Methods To address this, we employ single cell transcriptomics to compare primary pancreatic vs. liver PDAC lesions. Using a ligand-receptor interaction tool, we assess upregulated pathways in liver PDAC. Results Here, we identify the expression of hepatocyte growth factor (HGF) in fibroblasts and its receptor MET in cancer cells are both markedly increased in the PDAC liver niche. Using functional assays, we validate that mitogenic MET signaling is activated in PDAC cells by liver-derived fibroblasts. Importantly, the inhibition of MET signaling leads to reduced tumor growth in immune competent mouse models. Conclusions Collectively, our data demonstrates that liver stromal-epithelial crosstalk networks engage in signaling pathways distinct from primary pancreatic tumors, highlighting opportunities to develop new treatments for metastatic disease.
