Induction of lactoferrin gene expression by innate immune stimuli in mouse mammary epithelial HC-11 cells.
Lactoferrin (LF) is a multifunctional protein. While its functions and mechanism of actions are actively being investigated, the cellular signals that regulate LF expression have not been as explored. We have previously demonstrated that LF is upregulated by estrogen in the reproductive system. In this study, we show that the expression of LF was stimulated by bacterial lipopolysaccharide (LPS) and double-stranded RNA (dsRNA) in normal mouse mammalian HC-11 cells. When cells were exposed to either LPS or dsRNA, the mRNA and protein of LF were increased in a dose- and time-dependent manner, yet the kinetics of LF induction by dsRNA or LPS were different. The LPS and dsRNA-induced LF was mainly released into the culture medium where it blocked TNF-alpha production in exposed cells. We explored the mechanisms of LF induction by LPS and dsRNA using specific inhibitors and found that the induction could be attenuated by inhibitors to PKC, NF-kappaB, p38 and JNK, but not by an inhibitor to PKA. Interestingly, ERK inhibitor was effective against dsRNA but not against LPS induction of LF. These data suggest that LF was induced by LPS and dsRNA through PKC, NF-kappaB and MAPK pathways which in turn play an inhibitory role in the continuation of innate inflammation.
Gene Regulation Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
Yin
Y
Li
Gino V
GV
Limmon
Farhad
F
Imani
Christina
C
Teng
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects*; D007781:Lactoferrin / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000166:cytology*; D051379:Mice; D018613:Microscopy, Confocal; D009281:Naphthalenes / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology; D012330:RNA, Double-Stranded / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013873:Thionucleotides / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C105593:8-bromoadenosine-3',5'-cyclic monophosphorothioate; D016207:Cytokines; D008070:Lipopolysaccharides; D009281:Naphthalenes; D012330:RNA, Double-Stranded; D013873:Thionucleotides; D014409:Tumor Necrosis Factor-alpha; D015124:8-Bromo Cyclic Adenosine Monophosphate; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D007781:Lactoferrin; C058819:calphostin C