title: Up-regulation of integrin α6β4 expression by mitogens involved in dairy cow mammary development.
abstract: In dairy cows, the extracellular microenvironment varies significantly from the virgin state to lactation. The function of integrin α6β4 is dependent on cell type and extracellular microenvironment, and the precise expression profile of α6β4 and its effects on mammary development remain to be determined. In the present study, real-time PCR and immunohistochemistry were used to analyze the expression and localization of integrin α6β4 in Holstein dairy cow mammary glands. The effects of integrin α6β4 on the proliferation induced by mammogenic mitogens were identified by blocking integrin function in purified dairy cow mammary epithelial cells (DCMECs). The results showed that the localization of β4 subunit and its exclusive partner the α6 subunit were not consistent but were co-localized in basal luminal cells and myoepithelial cells, appearing to prefer the basal surface of the plasma membrane. Moreover, α6 and β4 subunit messenger RNA (mRNA) levels changed throughout the stages of dairy cow mammary development, reflected well by protein levels, and remained higher in the virgin and pregnancy states, with duct/alveolus morphogenesis and active cell proliferation, than during lactation, when growth arrest is essential for mammary epithelial cell differentiation. Finally, the upregulation of integrin expression by both mammogenic growth hormone and insulin-like growth factor-1 and the inhibited growth of DCMECs by function-blocking integrin antibodies confirmed that integrin α6β4 was indeed involved in dairy cow mammary development.
authors.affiliation: Key laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin, 150030, Heilongjiang, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.forename: Yu-Meng
authors.initials: YM
authors.lastname: Hao
authors.forename: Bo
authors.initials: B
authors.lastname: Qu
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: Cui
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.forename: Xue-Jun
authors.initials: XJ
authors.lastname: Gao
authors.forename: Qing-Zhang
authors.initials: QZ
authors.lastname: Li
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D003612:Dairying; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D013006:Growth Hormone / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D039161:Integrin alpha6beta4 / Q000235:genetics* / Q000378:metabolism; D007797:Laminin / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D008934:Mitogens / Q000494:pharmacology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics*
chemical_list: D039161:Integrin alpha6beta4; D007797:Laminin; D008934:Mitogens; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone