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Blocking DCIR mitigates colitis and prevents colorectal tumors by enhancing the GM-CSF-STAT5 pathway

ABSTRACT: Dendritic cell immunoreceptor (DCIR; gene: Clec4a2), a member of the C-type lectin receptor family, plays important roles in homeostasis of the immune and bone systems. However, the intestinal role of this molecule is unclear. Here, we showed that the severity of dextran sodium sulfate (DSS)–induced colitis and the incidence of azoxymethane-DSS–induced intestinal tumors was reduced in Clec4a2–/– mice in an intestinal microbiota–independent manner. STAT5 phosphorylation and expression of Csf2 and tight junction genes were enhanced, while expression of Il17a and Cxcl2 was suppressed in the Clec4a2–/– mouse, which exhibited reduced infiltration of neutrophils and myeloid-derived suppressor cells. GM-CSF administration ameliorated DSS colitis associated with reduced Il17a and enhanced tight junction gene expression, whereas anti–GM-CSF significantly exacerbated the symptoms. Furthermore, blocking the ligand-DCIR interaction ameliorated colitis and prevented colorectal tumors. These observations indicate that blocking DCIR signaling ameliorate colitis and suppresses colonic tumors, suggesting DCIR as a possible target for the treatment of these diseases.

ORGANISM(S): Mus musculus

PROVIDER: GSE190527 | GEO | 2024/12/01

REPOSITORIES: GEO

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Project description:Purpose: PKM2-mediated metabolic switch to aerobic glycolysis plays a critical role in promoting cell survival and proliferation. However, little is known about the function of intestinal epithelial PKM2 in intestinal homeostasis. Here we investigated whether and how intestinal epithelial PKM2 modulates the morphology and function of the adult intestine in experimental murine colitis. Methods: Colonoscopic biopsies from the Crohn’s disease (CD) and ulcerative colitis (UC) patients (10 each) were analyzed for PKM2 expression. We also generated intestinal epithelial-specific Pkm2 knockout mice and employed them to examine PKM2 function. Mouse intestinal inflammation was induced with dextran sulfate sodium (DSS) in drinking water. Disease phenotypes were investigated by mouse survival, body weight, colon length and analysis of immune cell infiltration in colon, intestinal epithelial cell gene profiling and signal pathway. Results: Intestinal epithelial PKM2 level in UC and CD patients was significantly decreased compared to that from non-inflamed intestinal epithelium. Similar reduction of intestinal epithelial PKM2 was observed in mice with experimental colitis. Supporting the notion that PKM2 serves as a safeguard against colitis, intestinal epithelial-specific Pkm2-deficient (Pkm2-/-) mice displayed a severer intestinal inflammation, companying with shortened colon, disruption of epithelial tight junction, higher permeability, elevation of inflammatory cytokines and immune cell infiltration, compared with wild-type mice. Gene profiling and western blot analysis indicated that cell survival signaling, particularly the Akt/β-catenin pathways, were downregulated in Pkm2-/- mice. Functional assay using mouse primary colonic epithelial cells confirmed that Pkm2 reduction decreased proliferation and migration of epithelial cells, while enhanced expression of Pkm2 was associated with increased transcriptional activity of β-catenin. Moreover, increasing mouse intestinal epithelial Pkm2 expression via delivery of Pkm2-expressing plasmid attenuated DSS-induced experimental colitis. Conclusions: Intestinal epithelial PKM2, through activating Wnt/β-catenin signaling, induces a strong proliferative and migratory response that increases cell survival and wound healing under colitic condition.

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Blocking DCIR mitigates colitis and prevents colorectal tumors by enhancing the GM-CSF-STAT5 pathway

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