Mammalian milk paradigm secretion, transport functional uptake mobile silen RNA

在植物和无脊椎动物中，长RNA和沉默小RNA在细胞之间移动， 在遥远的组织中发挥调节功能。Recenfly，哺乳动物分泌的微泡 体液和细胞外空间中发现含有RNA;这些，此外，可能是 在受体细胞中内化。在血清中也检测到称为Argonautes（AGO）的sRNA效应蛋白。 这些发现刺激了推测，哺乳动物细胞外RNA结合到脂质和/或效应物 蛋白质在被靶细胞/组织摄取后可能具有生物学功能。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RNAi，是第一个建立RNA沉默，内膜之间的联系， 和哺乳动物细胞中的囊泡运输。最近，我们发现人奶和牛奶 含有生理量的调节微（mi）RNA，特别是在乳脂球中 (MFG)，新生儿的脂肪来源。此外，我们还在MFG中检测到大量的特定AGO 和其他牛奶组分，这表明AGO结合的miRNA，也许还有其他RNA，可能在功能上是 转移到新生的肠道上皮细胞，也许是在进食过程中转移到远处的器官。利用 从麦克马纳斯和亨特那里获得的强大的小鼠和细胞遗传工具的集合 实验室，我们建议在这里使用哺乳动物的牛奶-一个容易获得和丰富的体液-作为一个 研究（i）乳腺分泌miRNA的基础机制，（ii） 牛奶中所含miRNAs的蛋白质和脂质环境，包括可能的新型牛奶相关AGO （iii）肠道上皮细胞摄取牛奶miRNA的基础机制，以及（iv）如果是乳源性的， 在喂养过程中从母亲转移到幼崽的miRNAs在小鼠中有效地显示生物活性 新生儿从这些知识和跨王国RNAi转移的明确先例中， 植物和寄生无脊椎动物，我们将最终解决，利用我们独特的植物-哺乳动物双重专业知识，如果 来源于农作物的饮食RNA可以被植物喂养的小鼠的肠上皮功能性地摄取。

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.