Differential expression and secretion of bovine serum amyloid A3 (SAA3) by mammary epithelial cells stimulated with prolactin or lipopolysaccharide.
Serum amyloid A (SAA) proteins were originally identified as prominent acute phase serum reactants synthesized predominately by hepatocytes in response to infection, inflammation and trauma. In this study, we report the differential expression and secretion of serum amyloid A3 (SAA3) by bovine mammary epithelial cells following stimulation with either prolactin (PRL) or lipopolysaccharide (LPS). Reverse transcription-polymerase chain reaction analysis of PRL or LPS induced bovine mammary epithelial cells resulted in the detection of only the mammary-derived Saa3 (M-Saa3) transcript. Two-dimensional immunoblot analyses of colostrum and milk from healthy cows, as well as conditioned medium from PRL or LPS stimulated bovine mammary epithelial cells confirmed the differential production and secretion of M-SAA3 while other SAA isoforms were not detected. These data indicate that the bovine Saa3 gene is regulated differently from the other Saa genes with regard to the site of and stimulus for expression, suggesting an important tissue-specific function for bovine M-SAA3 during lactation and mammary infection.
Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Marilynn A
MA
Larson
Annika
A
Weber
Allen T
AT
Weber
Thomas L
TL
McDonald
D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000097:blood* / Q000235:genetics*; D002460:Cell Line; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D015151:Immunoblotting; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D011388:Prolactin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000685:Serum Amyloid A Protein / Q000096:biosynthesis* / Q000235:genetics*
D008070:Lipopolysaccharides; D012333:RNA, Messenger; D000685:Serum Amyloid A Protein; D011388:Prolactin