Mammalian milk paradigm secretion, transport functional uptake mobile silen RNA

在植物和无脊椎动物中，长的RNA和沉默的小(S)RNA在细胞之间移动，并超过 在遥远的组织中发挥调节功能的距离。哺乳动物体内分泌的微泡--新蝇 体液和细胞外空间中发现含有RNA；此外，这些可能是 内化在受体细胞中。在血清中也检测到名为Argavites(Agos)的sRNA效应蛋白。 这些发现刺激了人们对哺乳动物细胞外RNA与脂质和/或效应器结合的推测 蛋白质在被靶细胞/组织摄取后可能具有生物学功能。很少，如果有的话， 然而，目前的实验证据支持这一观点。我们的实验室率先研究了 非细胞自主的RNAi，是最早在RNA沉默、内膜和 和哺乳动物细胞中的囊泡运输。最近，我们发现人奶和牛奶 含有生理数量的调节微小(Mi)rna，特别是在乳脂球中。 (MFG)，新生儿脂肪的来源。此外，我们还在MFG中检测到大量的特殊成分 和其他牛奶组分，这表明与前结合的miRNA，也许还有其他RNA，可能在功能上 在进食过程中，转移到新生的肠道上皮，可能还有远处的器官。利用 来自McManus和Hunter的强大的老鼠和基于细胞的遗传工具的集合 在实验室，我们建议使用哺乳动物的奶-一种容易获得和丰富的身体蓝色-作为一种 研究(I)支持乳腺miRNA分泌的机制，(Ii) 含有牛奶的miRNAs的蛋白质和脂肪环境，包括可能与牛奶相关的新的AGO 合作伙伴，(Iii)支持肠道上皮摄取牛奶miRNA的机制，以及(Iv)是否由牛奶传播 喂食过程中从母体转移到幼鼠体内的miRNAs在小鼠体内有效地显示了生物活性 新生儿。根据这一知识和跨王国RNAi转移的明确先例 植物和寄生无脊椎动物，我们最后将利用我们独特的植物-哺乳动物双重专业知识，如果 来自农作物的膳食RNA可以被植物喂养的小鼠的肠道上皮细胞功能性地摄取。

In plants and invertebrates, long RNAs and silencing small (s)RNAs move between cells and over long distances to exert regulatory functions in remote tissues. Recenfly, micro-vesicles secreted in mammalian body fluids and in the extra-cellular space were found to contain RNA; these, moreover, might be internalized in recipient cells. sRNA effector proteins called Argonautes (AGOs) were also detected in serum. These findings have spurred speculaflons that mammalian extracellular RNAs bound to lipids and/or effector proteins might have biological functions following their uptake by target cells/tissues. Little, if any, experimental evidence presently supports this idea, however. Our laboratory has pioneered research on non-cell autonomous RNAi and was among the first to establish a link between RNA silencing, endomembranes and vesicle trafficking in mammalian cells. Recently, we discovered that human and bovine milk contains physiological amounts of regulatory micro (mi)RNAs concentrated, notably, in milk fat globules (MFG), the source of fat for newborns. Moreover, we also detected high amounts of speciflc AGOs in MFG and other milk fractions, suggesting that AGO-bound miRNA, and perhaps other RNAs, might be functionally transferred into the new born gut epithelium and, perhaps distant organs, during feeding. Taking advantage of the formidable collection of mouse and cell-based genetic tools available from the McManus and Hunter laboratories, we propose here to use mammalian milk -an easily accessible and abundant body bluid- as a paradigm to investigate (i) the mechanisms underpinning miRNA secretion from the mammary gland, (ii) the protein and lipid environment of milk-contained miRNAs, including possibly novel milk-associated AGO partners, (iii) the mechanisms underpinning milk miRNA uptake by the gut epithelium, and (iv) if milk-borne miRNAs transferred from mother to pup during feeding effectively display biological activity in mouse newborns. Drawing from this knowledge and on clear precedents of trans-kingdom RNAi transfer between plants and parasific invertebrates, we will finally address, using our unique plant-mammal dual expertise, if dietary RNA derived from crops can be functionally taken up by the gut epithelium of plant-fed mice.