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Milk electrolytes and cytokine exposure modulate mammary epithelial barrier function via occludin
Author(s) -
Quesnell Rebecca R,
Schultz Bruce D
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1284-b
Subject(s) - occludin , barrier function , tight junction , cytokine , chemistry , epithelium , tumor necrosis factor alpha , microbiology and biotechnology , endocrinology , medicine , biology , immunology , pathology
The aims of this study were to elucidate the mechanisms by which apical electrolytes and cytokines compromise barrier function of bovine mammary epithelium. Previous work demonstrated that bovine mammary epithelial cell monolayers exposed to high apical electrolytes (HE) as compared to low apical electrolytes (LE) exhibited compromised barrier function as assessed by measurement of transepithelial electrical resistance (Rte). BME‐UV cells were grown to confluence on permeable supports with a standard basolateral medium and either HE or LE apical medium for 14 days. Rte was highest in monolayers continuously exposed to apical LE. Time‐dependent decline in Rte began by 24 hours of HE exposure. Change from HE to LE demonstrated time‐dependent increase in Rte. Indirect immunofluorescence employing antibodies for the tight junction proteins occludin (OC) and zonula occludins 1 (ZO) demonstrated significant alteration in OC distribution concomitant with the changes in Rte, but no change in ZO. In a separate set of experiments, BME‐UV cell monolayers, cultured in the presence of LE apical medium, were exposed to cytokines associated with mammary inflammation, including tumor necrosis factor alpha (TNF‐á; 0.5 ìg/mL), interleukin‐1 (IL‐1â,; 0.1 ìg/mL) or interleukin‐6 (IL‐6; 1 ìg/mL) in the apical medium for 8 or 12 hours prior to assay. TNF‐á, but not IL‐1â or IL‐6, caused significant decrease in Rte. These results indicate that mammary epithelium is a dynamic barrier that is acutely modulated by cytokines and the luminal electrolyte environment at least in part via modulation of occludin. [Supported by USDA 2003‐35206‐14157 & KS Ag Exp Station]