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Bacterial lipopolysaccharide induces increased expression of toll-like receptor (TLR) 4 and downstream TLR signaling molecules in bovine mammary epithelial cells

Eveline M Ibeagha-Awemu, Jai-Wei lee, Aloysius E Ibeagha, Douglas D Bannerman, Max Paape UGent and Xin Zhao (2008) VETERINARY RESEARCH. 39(2).
abstract
Bovine mammary epithelial cells contribute to the innate immune response to intramammary infections by recognizing pathogens through specialized pattern recognition receptors. Toll-like receptor 4 (TLR4) is one such receptor that binds and is activated by lipopolysaccharide (LPS), a component of the outer envelope of Gram-negative bacteria. In this study, MAC-T cells ( a bovine mammary epithelial cell line) were incubated in the presence or absence of increasing concentrations of LPS for 24 h. Expression of TLR2 and TLR4 were analyzed at both mRNA and protein levels by quantitative real-time PCR (qPCR) and flow cytometry, respectively. The mRNA of both receptors were up-regulated by all concentrations of LPS used ( P < 0.01). Similarly, flow cytometry with specific antibodies against TLR2 and TLR4 detected increased surface expression of these proteins. Furthermore, expression of downstream TLR4 signaling molecules was examined by qPCR following varying exposure times to 1 mu g/mL of LPS. Results demonstrate that the required adaptor molecules and transcription factors were up-regulated in a time-dependent manner. Both the MyD88 dependent and independent pathways in TLR4 signaling were activated in MACT cells. Expression of TOLLIP increased in response to LPS as did the pro-apoptotic protease, CASP8. These results suggest that the bovine mammary epithelium possesses the necessary immune repertoires required to achieve a robust defense against E. coli. The current findings, coupled with previous findings that S. aureus ligands induce up-regulation of TLR4, may indicate a positive adaptation by mammary epithelial cells to effectively respond to different types of mastitis pathogens.
Please use this url to cite or link to this publication:
author
organization
year
type
journalArticle (original)
publication status
published
subject
keyword
NF-KAPPA-B, mastitis, INNATE IMMUNE-RESPONSE, REAL-TIME PCR, ENDOTHELIAL-CELLS, ESCHERICHIA-COLI, WALL COMPONENTS, GENE-EXPRESSION, MESSENGER-RNA, UP-REGULATION, CUTTING EDGE, bovine mammary epithelial cells, TLR4 and TLR2, signal transduction, lipopolysaccharide
journal title
VETERINARY RESEARCH
Vet. Res.
volume
39
issue
2
pages
- pages
Web of Science type
Article
Web of Science id
000254623700001
JCR category
VETERINARY SCIENCES
JCR impact factor
3.06 (2008)
JCR rank
4/133 (2008)
JCR quartile
1 (2008)
ISSN
0928-4249
DOI
10.1051/vetres:2007047
language
English
UGent publication?
no
classification
A1
additional info
article no. 11 (12 p.)
copyright statement
I have transferred the copyright for this publication to the publisher
id
429149
handle
http://hdl.handle.net/1854/LU-429149
date created
2008-08-27 17:35:00
date last changed
2010-01-20 14:01:14
@article{429149,
  abstract     = {Bovine mammary epithelial cells contribute to the innate immune response to intramammary infections by recognizing pathogens through specialized pattern recognition receptors. Toll-like receptor 4 (TLR4) is one such receptor that binds and is activated by lipopolysaccharide (LPS), a component of the outer envelope of Gram-negative bacteria. In this study, MAC-T cells ( a bovine mammary epithelial cell line) were incubated in the presence or absence of increasing concentrations of LPS for 24 h. Expression of TLR2 and TLR4 were analyzed at both mRNA and protein levels by quantitative real-time PCR (qPCR) and flow cytometry, respectively. The mRNA of both receptors were up-regulated by all concentrations of LPS used ( P {\textlangle} 0.01). Similarly, flow cytometry with specific antibodies against TLR2 and TLR4 detected increased surface expression of these proteins. Furthermore, expression of downstream TLR4 signaling molecules was examined by qPCR following varying exposure times to 1 mu g/mL of LPS. Results demonstrate that the required adaptor molecules and transcription factors were up-regulated in a time-dependent manner. Both the MyD88 dependent and independent pathways in TLR4 signaling were activated in MACT cells. Expression of TOLLIP increased in response to LPS as did the pro-apoptotic protease, CASP8. These results suggest that the bovine mammary epithelium possesses the necessary immune repertoires required to achieve a robust defense against E. coli. The current findings, coupled with previous findings that S. aureus ligands induce up-regulation of TLR4, may indicate a positive adaptation by mammary epithelial cells to effectively respond to different types of mastitis pathogens.},
  author       = {Ibeagha-Awemu, Eveline M and lee, Jai-Wei and Ibeagha, Aloysius E and Bannerman, Douglas D and Paape, Max and Zhao, Xin},
  issn         = {0928-4249},
  journal      = {VETERINARY RESEARCH},
  keyword      = {NF-KAPPA-B,mastitis,INNATE IMMUNE-RESPONSE,REAL-TIME PCR,ENDOTHELIAL-CELLS,ESCHERICHIA-COLI,WALL COMPONENTS,GENE-EXPRESSION,MESSENGER-RNA,UP-REGULATION,CUTTING EDGE,bovine mammary epithelial cells,TLR4 and TLR2,signal transduction,lipopolysaccharide},
  language     = {eng},
  number       = {2},
  pages        = {-},
  title        = {Bacterial lipopolysaccharide induces increased expression of toll-like receptor (TLR) 4 and downstream TLR signaling molecules in bovine mammary epithelial cells},
  url          = {http://dx.doi.org/10.1051/vetres:2007047},
  volume       = {39},
  year         = {2008},
}

Chicago
Ibeagha-Awemu, Eveline M, Jai-Wei lee, Aloysius E Ibeagha, Douglas D Bannerman, Max Paape, and Xin Zhao. 2008. “Bacterial Lipopolysaccharide Induces Increased Expression of Toll-like Receptor (TLR) 4 and Downstream TLR Signaling Molecules in Bovine Mammary Epithelial Cells.” Veterinary Research 39 (2).
APA
Ibeagha-Awemu, E. M., lee, J.-W., Ibeagha, A. E., Bannerman, D. D., Paape, M., & Zhao, X. (2008). Bacterial lipopolysaccharide induces increased expression of toll-like receptor (TLR) 4 and downstream TLR signaling molecules in bovine mammary epithelial cells. VETERINARY RESEARCH, 39(2).
Vancouver
1.
Ibeagha-Awemu EM, lee J-W, Ibeagha AE, Bannerman DD, Paape M, Zhao X. Bacterial lipopolysaccharide induces increased expression of toll-like receptor (TLR) 4 and downstream TLR signaling molecules in bovine mammary epithelial cells. VETERINARY RESEARCH. 2008;39(2).
MLA
Ibeagha-Awemu, Eveline M, Jai-Wei lee, Aloysius E Ibeagha, et al. “Bacterial Lipopolysaccharide Induces Increased Expression of Toll-like Receptor (TLR) 4 and Downstream TLR Signaling Molecules in Bovine Mammary Epithelial Cells.” VETERINARY RESEARCH 39.2 (2008): n. pag. Print.