title: Milk is not just food but most likely a genetic transfection system activating mTORC1 signaling for postnatal growth.
abstract: Milk has been recognized to represent a functionally active nutrient system promoting neonatal growth of mammals. Cell growth is regulated by the nutrient-sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1). There is still a lack of information on the mechanisms of mTORC1 up-regulation by milk consumption. This review presents milk as a materno-neonatal relay system functioning by transfer of preferential amino acids, which increase plasma levels of glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), insulin, growth hormone (GH) and insulin-like growth factor-1 (IGF-1) for mTORC1 activation. Importantly, milk exosomes, which regularly contain microRNA-21, most likely represent a genetic transfection system enhancing mTORC1-driven metabolic processes. Whereas human breast milk is the ideal food for infants allowing appropriate postnatal growth and species-specific metabolic programming, persistent high milk signaling during adolescence and adulthood by continued cow´s milk consumption may promote mTORC1-driven diseases of civilization.
authors.affiliation: Department of Dermatology, Environmental Medicine and Health Theory, University of Osnabrück, Sedanstrasse 115, D-49090, Osnabrück, Germany. melnik@t-online.de
authors.forename: Bodo C
authors.initials: BC
authors.lastname: Melnik
authors.forename: Swen Malte
authors.initials: SM
authors.lastname: John
authors.forename: Gerd
authors.initials: G
authors.lastname: Schmitz
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D005749:Gastric Inhibitory Polypeptide / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007223:Infant; D007227:Infant Nutritional Physiological Phenomena; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D008892:Milk / Q000737:chemistry*; D008895:Milk, Human / Q000737:chemistry; D046912:Multiprotein Complexes / Q000235:genetics* / Q000378:metabolism; D011181:Postnatal Care; D015398:Signal Transduction; D058570:TOR Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation
chemical_list: D000596:Amino Acids; D007328:Insulin; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D046912:Multiprotein Complexes; D019382:Human Growth Hormone; D005749:Gastric Inhibitory Polypeptide; D007334:Insulin-Like Growth Factor I; D052216:Glucagon-Like Peptide 1; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases