Glucagon-like peptide-2 (GLP-2), a key factor in intestinal rehabilitation therapy of short bowel syndrome (SBS), may require cell-to-cell communication to exert its biological functions. However, understanding of the mechanism remains elusive. Here, we report participation of exosomal miR-125a/b in GLP-2 mediated intestinal epithelial cells-myofibroblasts cross-talk in intestinal microenvironment./nMethods: The effects of GLP-2 on the proliferation and apoptosis of intestinal epithelial cells in SBS rat models were evaluated. Exosomes were extracted from residual jejunum tissue of GLP-2 or vehicle treated SBS rats using ultracentrifugation method, and identified by nanoparticle trafficking analysis (NTA), transmission electron microscopy and western blotting. miRNA sequencing combined with qRT-PCR validation were used to identify differentially expressed miRNAs. miRNAs, which might be involved in proliferation and apoptosis of intestinal epithelial cells, were screened and further verified by miRNA functional experiments. Moreover, the proliferation-promoting and anti-apoptosis effects of GLP-2 on intestinal myofibroblasts, which expressing GLP-2 receptor, and whether GLP-2 could influence the content of miRNAs in the derived exosomes were studied. The downstream pathways were explored by miRNA function recovery experiment, luciferase reporter assay, pull down experiment, knockdown and overexpression of target gene and other experiments based on the bioinformatics prediction of miRNA target gene./nResults: GLP-2 significantly promoted intestinal growth, facilitated the proliferation of intestinal crypt epithelial cells and inhibited the apoptosis of intestinal villi epithelial cells in type II SBS rats. GLP-2 significantly down-regulated exosomal miR-125a/b both in residual jejunums derived exosomes and in exosomes secreted by GLP-2R positive cells. Exosomal miR-125a/b was responsible for GLP-2 mediated intestinal epithelial cells proliferation promotion and apoptosis attenuation. miR-125a/b inhibited the proliferation and promotes apoptosis of intestinal epithelial cells by suppressing the myeloid cell leukemia-1 (MCL1)./nConclusions: miR-125a/b shuttled by intestinal myofibroblasts derived exosomes regulate the proliferation and apoptosis of intestinal epithelial cells. GLP-2 treatment significantly decreases the level of miR-125a/b in the exosomes of intestinal myofibroblasts. miR-125a/b modulates the proliferation and apoptosis of intestinal epithelial cells by targeting the 3'UTR region of MCL1. Hence, this study indicates a novel mechanism of genetic exchange between cells in intestinal microenvironment.

中文翻译：

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外来体介导的miR-125a / b在细胞间通讯中的转移：肠道微环境中遗传交换的新机制。

胰高血糖素样肽2（GLP-2）是短肠综合征（SBS）肠道康复治疗中的关键因素，可能需要细胞间通讯才能发挥其生物学功能。但是，对该机制的了解仍然难以捉摸。在这里，我们报告的外来体的miR-125A / B的参与GLP-2介导的肠上皮细胞，肌成纤维细胞串扰肠道microenvironment./n方法：评估了GLP-2对SBS大鼠模型肠道小肠上皮细胞增殖和凋亡的影响。使用超速离心方法从GLP-2残留的空肠组织或经媒介物处理的SBS大鼠中提取外泌体，并通过纳米颗粒运输分析（NTA），透射电子显微镜和Western印迹进行鉴定。miRNA测序与qRT-PCR验证相结合，用于鉴定差异表达的miRNA。筛选可能参与肠道上皮细胞增殖和凋亡的miRNA，并通过miRNA功能实验进一步验证。此外，研究了GLP-2对表达GLP-2受体的肠成肌纤维细胞的增殖促进和抗凋亡作用，以及GLP-2是否可以影响衍生的外泌体中miRNA的含量。结果： GLP-2可显着促进II型SBS大鼠肠道小肠隐窝上皮细胞的增殖，并抑制其肠绒毛上皮细胞的凋亡。在残留空肠来源的外泌体和GLP-2R阳性细胞分泌的外泌体中，GLP-2均显着下调了外泌体miR-125a / b。外泌体miR-125a / b负责GLP-2介导的肠上皮细胞增殖促进和凋亡减弱。的miR-125A / B抑制增殖和通过抑制骨髓细胞白血病-1（MCL1）./Ñ促进肠上皮细胞的凋亡结论：肠道成肌纤维细胞来源的外来体穿梭的miR-125a / b调节肠道上皮细胞的增殖和凋亡。GLP-2处理可显着降低肠道成肌纤维细胞外泌体中miR-125a / b的水平。miR-125a / b通过靶向MCL1的3'UTR区域来调节肠道上皮细胞的增殖和凋亡。因此，这项研究表明了肠道微环境中细胞之间遗传交换的新机制。