No effect of an elevated miR-30b level in mouse milk on its level in pup tissues

Recent reports have shown that ingested microRNAs may be transferred to blood, accumulate in tissues and exert canonical regulation on endogenous transcripts. In spite of several attempts to replicate these findings, they have not been confirmed and several questions remain. By using a transgenic mouse model presenting a high level of miR-30b in milk, the horizontal delivery of this microRNA via oral ingestion was studied in pups. Our findings demonstrated that, although very high levels of miR-30b were found in milk and in stomach contents of the pups, we did not detect an increase in miR-30b in tissues of pups fed by transgenic females compared to pups fed by wild-type females.

近期研究表明，经摄入的微小核糖核酸（microRNA）可进入血液、在组织中蓄积，并对内源转录本发挥经典调控作用。尽管已有多项研究尝试重复上述发现，但均未得到验证，仍有诸多疑问有待解答。本研究通过构建乳汁中高表达miR-30b的转基因小鼠模型，针对幼鼠开展了该微小核糖核酸经口摄入的横向递送研究。结果显示，尽管在乳汁及幼鼠胃内容物中均检测到了极高水平的miR-30b，但与野生型母鼠哺育的幼鼠相比，转基因母鼠哺育的幼鼠组织内miR-30b水平并未出现升高。