ARF1 maintains intestinal homeostasis by modulating gut microbiota and stem cell function

The small GTPase protein ARF1 has been shown to be involved in the lipolysis pathway and to selectively kill stem cells in Drosophila melanogaster. However, the role of ARF1 in mammalian intestinal homeostasis remains elusive. This study aimed to explore the role of ARF1 in intestinal epithelial cells (IECs) and reveal the possible mechanism. IEC-specific ARF1 deletion mouse model was used to evaluate the role of ARF1 in intestine. Immunohistochemistry and immunofluorescence analyses were performed to detect specific cell type markers, and intestinal organoids were cultured to assess intestinal stem cell (ISC) proliferation and differentiation. Fluorescence in situ hybridization, 16S rRNA-seq analysis, and antibiotic treatments were conducted to elucidate the role of gut microbes in ARF1-mediated intestinal function and the underlying mechanism. Colitis was induced in control and ARF1-deficient mice by dextran sulfate sodium (DSS). RNA-seq was performed to elucidate the transcriptomic changes after ARF1 deletion. ARF1 was essential for ISC proliferation and differentiation. Loss of ARF1 increased susceptibility to DSS-induced colitis and gut microbial dysbiosis. Gut microbiota depletion by antibiotics could rescue the intestinal abnormalities to a certain extent. Furthermore, RNA-seq analysis revealed alterations in multiple metabolic pathways. This work is the first to elucidate the essential role of ARF1 in regulating gut homeostasis, and provides novel insights into the pathogenesis of intestinal diseases and potential therapeutic targets.