Feces are enriched with microRNAs (miRNAs) that shape the gut microbiota. These miRNAs are differentially expressed in the feces of healthy and diseased subjects. However, whether fecal miRNAs in subjects with inflammatory bowel diseases are involved in regulating microbiota composition and whether they have any beneficial effects remains unknown. Here, we studied the fecal microbiome composition and miRNA abundance in mice with dextran sulfate sodium (DSS)-induced colitis and mice at the recovery phase to explore different miRNAs expressed, their relations with microbial abundance, and their effects on colitis. We found that miR-142a-3p expression was significantly increased in the feces of mice recovered from colitis and that it could alleviate disease symptoms in mice treated with DSS in a microbiome-dependent manner. Specifically, miR-142a-3p promoted the growth of Lactobacillus reuteri, which had a high abundance in the feces of mice recovered from colitis, by regulating transcripts of polA and locus tag LREU_RS03575. Moreover, L. reuteri, as well as its metabolite reuterin, could alleviate DSS-induced disease symptoms. These results highlight the role of fecal miR-142a-3p in the prevention of colitis. We propose that the feces of subjects who have recovered from diseases might be enriched with miRNAs with preventive effects against those diseases.

粪便中富含可塑造肠道微生物群的 microRNA (miRNA)。这些 miRNA 在健康和患病受试者的粪便中差异表达。然而，炎症性肠病患者的粪便 miRNA 是否参与调节微生物群组成以及它们是否具有任何有益作用仍然未知。在这里，我们研究了葡聚糖硫酸钠 (DSS) 诱导的结肠炎小鼠和恢复期小鼠的粪便微生物组组成和 miRNA 丰度，以探索表达的不同 miRNA、它们与微生物丰度的关系以及它们对结肠炎的影响。我们发现 miR-142a-3p 表达在从结肠炎中恢复的小鼠粪便中显着增加，并且它可以以微生物组依赖性方式减轻用 DSS 治疗的小鼠的疾病症状。具体来说，罗伊氏乳杆菌通过调节polA和基因座标签 LREU_RS03575的转录本，在从结肠炎中恢复的小鼠粪便中具有高丰度。此外，罗伊氏乳杆菌及其代谢物罗伊氏素可以减轻 DSS 引起的疾病症状。这些结果突出了粪便 miR-142a-3p 在预防结肠炎中的作用。我们建议，从疾病中康复的受试者的粪便中可能富含对这些疾病具有预防作用的 miRNA。