Distinct roles of prolactin, epidermal growth factor, and glucocorticoids in β-casein secretion pathway in lactating mammary epithelial cells. (15th January 2017)

• Record Type: Journal Article
• Authors: Kobayashi, Ken; Oyama, Shoko; Kuki, Chinatsu; Tsugami, Yusaku; Matsunaga, Kota; Suzuki, Takahiro; Nishimura, Takanori
• Is Part Of: Molecular and cellular endocrinology. Volume 440(2017)
• Page Start: 16
• Page End: 24
• Publication Date: 2017-01-15
• Subjects: Prolactin -- Epidermal growth factor -- Glucocorticoid -- Dexamethasone -- β-casein -- Mammary epithelial cell; DEX dexamethasone -- EGF epidermal growth factor -- EGFr EGF receptor -- FBS fetal bovine serum -- GR glucocorticoid receptor -- JAK2 Janus kinase 2 -- MEC mammary epithelial cell -- PBST PBS containing 0.05% Tween 20 -- PRL prolactin -- qPCR quantitative PCR -- RER rough endoplasmic reticulum -- RT reverse transcription -- SNARE Soluble N-ethylmaleimide-sensitive factor activating protein receptor -- STAT5 signal transducer and activator of transcription 5; Endocrinology -- Periodicals; Molecular biology -- Periodicals; Cytology -- Periodicals; Endocrinology -- Periodicals; Hormones -- Periodicals; Endocrinologie -- Périodiques; Cytology; Endocrinology; Molecular biology; Periodicals; 573.4
• DOI: 10.1016/j.mce.2016.11.006
• Languages: English
• ISSNs: 0303-7207

Abstract

Abstract: Beta-casein is a secretory protein contained in milk. Mammary epithelial cells (MECs) synthesize and secrete β-casein during lactation. However, it remains unclear how the β-casein secretion pathway is developed after parturition. In this study, we focused on prolactin (PRL), epidermal growth factor (EGF), and glucocorticoids, which increase in blood plasma and milk around parturition. MECs cultured with PRL, EGF and dexamethasone (DEX: glucocorticoid analog) developed the β-casein secretion pathway. In the absence of PRL, MECs hardly expressed β-casein. EGF enhanced the expression and secretion of β-casein in the presence of PRL and DEX. DEX treatment rapidly increased secreted β-casein concurrent with enhancing β-casein expression. DEX also up-regulated the expression of SNARE proteins, such as SNAP-23, VAMP-8 and Syntaxin-12. Furthermore, PRL and DEX regulated the expression ratio of αs1 -, β- and κ-casein. These results indicate that PRL, EGF and glucocorticoids have distinct roles in the establishment of β-casein secretion pathway. Highlights: Prolactin is indispensable for initiation of β-casein synthesis. Epidermal growth factor up-regulate β-casein expression. Glucocorticoids activate β-casein secretion with enhancing β-casein expression. Prolactin and glucocorticoids change the expression ratio of casein subtypes.