PROTEIN ARGININE METHYLTRANSFERASE 1 REGULATES ADULT INTESTINAL CELL PROLIFERATION AND ENTEROENDOCRINE CELLS DIFFERENTIATION

Abstract

Abstract The adult intestinal epithelium is a complex, self-renewing tissue composed of specialized cell types with diverse functions. Intestinal stem cells (ISCs) at the base of crypts divide and differentiate into absorptive and secretory cells. Enteroendocrine cells (EEC), one type of secretory cells, are the most abundant hormone-producing cells in mammals and involved in the control of energy homeostasis. Many studies investigated the mechanisms that control cell fate determination; however, regulation of EEC development and function are still unclear or controversial. Here, we found that Protein arginine methyltransferase 1(PRMT1), a major arginine methyltransferase, is highly expressed in the proliferating transit-amplifying (TA) cells and ISCs of adult mouse intestinal crypts. By using tamoxifen-induced intestinal epithelial cell-specific deletion of PRMT1 in adult mice, we observed the number of EEC dramatically increased. Transcription analyses showed the expression levels of Enteroendocrine-specific hormone and transcription factors are upregulated in PRMT1-deficient small intestine. In addition, the top enriched upregulated pathways were all associated with EEC functions. Concomitantly, Neurogenin 3-expressing progenitor cells accumulate in the mutant small intestine, and its target genes such as Neuod1, pax4, insm1 are upregulated of mutant crypts by RT-PCR. Furthermore, intestinal epithelium of the mutant mice showed elongated crypts in the small intestine, while increased cell proliferation in TA cells. Additionally, inducible PRMT1 deletion led to increased cell death, which compensated for increased cell proliferation in the crypts to maintain overall intestinal morphology and intestinal homeostasis. Together, our results revealed that the loss of PRMT1 in the adult intestinal epithelium altered TA cell proliferation and EEC differentiation, which was probably via Neurogenin 3-mediated pathway. Thus, our results may provide potential roles of PRMT1 as an essential transcriptional regulator of EECs specification and strategy for metabolic disorder.