title: Mammary alveolar epithelial cells convert to brown adipocytes in post-lactating mice.
abstract: During pregnancy and lactation, subcutaneous white adipocytes in the mouse mammary gland transdifferentiate reversibly to milk-secreting epithelial cells. In this study, we demonstrate by transmission electron microscopy that in the post-lactating mammary gland interscapular multilocular adipocytes found close to the mammary alveoli contain milk protein granules. Use of the Cre-loxP recombination system allowed showing that the involuting mammary gland of whey acidic protein-Cre/R26R mice, whose secretory alveolar cells express the lacZ gene during pregnancy, contains some X-Gal-stained and uncoupling protein 1-positive interscapular multilocular adipocytes. These data suggest that during mammary gland involution some milk-secreting epithelial cells in the anterior subcutaneous depot may transdifferentiate to brown adipocytes, highlighting a hitherto unappreciated feature of mouse adipose organ plasticity.
authors.affiliation: Department of Experimental and Clinical Medicine, University of Ancona (Università Politecnica delle Marche), Ancona, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Giordano
authors.affiliation: Department of Experimental and Clinical Medicine, University of Ancona (Università Politecnica delle Marche), Ancona, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Perugini
authors.affiliation: Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.
authors.forename: David M
authors.initials: DM
authors.lastname: Kristensen
authors.affiliation: Department of Experimental and Clinical Medicine, University of Ancona (Università Politecnica delle Marche), Ancona, Italy.
authors.forename: Loris
authors.initials: L
authors.lastname: Sartini
authors.affiliation: Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Frontini
authors.affiliation: UCSF Diabetes Center, University of California, San Francisco, California.
authors.forename: Shingo
authors.initials: S
authors.lastname: Kajimura
authors.affiliation: Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.|Institute of Metagenomics, BGI-Shenzen, Shenzen, China.
authors.forename: Karsten
authors.initials: K
authors.lastname: Kristiansen
authors.affiliation: Department of Experimental and Clinical Medicine, University of Ancona (Università Politecnica delle Marche), Ancona, Italy.|Center of Obesity, University of Ancona (Università Politecnica delle Marche)-United Hospitals, Ancona, Italy.
authors.forename: Saverio
authors.identifier: http://orcid.org/0000-0003-0362-5017
authors.initials: S
authors.lastname: Cinti
mesh_terms: D052437:Adipocytes, Brown / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D019070:Cell Lineage; D000066670:Cell Plasticity; D054338:Cell Transdifferentiation; D004847:Epithelial Cells / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D005838:Genotype; D019426:Integrases / Q000235:genetics; D007774:Lactation; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D008894:Milk Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D011247:Pregnancy; D022661:RNA, Untranslated / Q000235:genetics; D000071256:Uncoupling Protein 1 / Q000378:metabolism; D014886:Weaning; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: C110853:Gt(ROSA)26Sor non-coding RNA, mouse; D008894:Milk Proteins; D022661:RNA, Untranslated; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; C024471:whey acidic proteins; C045073:Cre recombinase; D019426:Integrases; D001616:beta-Galactosidase
keywords: Cre-loxP recombination system; adipose organ; electron microscopy; mammary gland; pregnancy