title: Underlying mechanisms involved in the decrease of milk secretion during Escherichia coli endotoxin induced mastitis in lactating mice.
abstract: Mastitis, the inflammation of mammary glands resulting from bacterial infection, disrupts milk production in lactating mammary glands. In this study, we injected lipopolysaccharide (LPS), one of the endotoxins from Escherichia coli into mouse mammary glands to disrupt milk production, and we investigated the influence of LPS on nutrient uptake, synthesis, and secretion processes for milk component production in alveolar epithelial cells (AEC). The expression of genes relevant to the three-staged milk component production process (nutrient uptake, synthesis, and secretion of milk components) were down-regulated within 12 h after LPS injection in AEC. The internalization of glucose transporter 1 (GLUT-1) from the basolateral membrane to the cytoplasm occurred in accordance with the down-regulation of gene expression 3 h after LPS injection. The abnormal localization of adipophilin and beta-casein was also observed in the LPS-injected mammary glands. SLC7A1, an amino acid transporter, was up-regulated 3 and 6 h after LPS injection. Furthermore, the inactivation of signal transducer and activator of transcription 5 (STAT5) and the activation of STAT3 and nuclear factor-kappa B (NFkappaB) occurred 3 h after LPS injection. These results indicate that the nutrient uptake, synthesis, and secretion of milk components in AEC are rapidly shut down in the lactating mammary glands after LPS injection.
authors.affiliation: Laboratory of Dairy Food Science, Research Faculty of Agriculture, Hokkaido University, North 9, West 9, Sapporo 060-8589, Japan. kkobaya@anim.agr.hokudai.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Shoko
authors.initials: S
authors.lastname: Oyama
authors.forename: Takaaki
authors.initials: T
authors.lastname: Uejyo
authors.forename: Chinatsu
authors.initials: C
authors.lastname: Kuki
authors.forename: Md Morshedur
authors.initials: MM
authors.lastname: Rahman
authors.forename: Haruto
authors.initials: H
authors.lastname: Kumura
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D004847:Epithelial Cells / Q000382:microbiology / Q000502:physiology; D004926:Escherichia coli; D004927:Escherichia coli Infections / Q000382:microbiology / Q000503:physiopathology / Q000662:veterinary*; D005260:Female; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D007774:Lactation; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000276:immunology*; D008321:Mammary Glands, Animal / Q000382:microbiology / Q000503:physiopathology*; D008413:Mastitis / Q000382:microbiology / Q000503:physiopathology / Q000662:veterinary*; D051379:Mice; D008813:Mice, Inbred ICR; D008892:Milk / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012376:Rodent Diseases / Q000382:microbiology / Q000503:physiopathology*
chemical_list: D008070:Lipopolysaccharides