Inflammatory cytokines induce MAdCAM-1 in murine hepatic endothelial cells and mediate alpha-4 beta-7 integrin dependent lymphocyte endothelial adhesion in vitro.
BACKGROUND
MAdCAM-1 plays a central role in T-lymphocyte homing to the gut, but its role in chronic liver inflammation remains unknown. Therefore, this study measured MAdCAM-1 expression, regulation, and function in cultured murine hepatic endothelial cells.


METHODS
Cultures of hepatic endothelial cells (HEC) were prepared from mice expressing a temperature-sensitive SV40 large T antigen (H-2Kb-tsA58) under the control of an IFN-gamma promoter. Time and dose dependent expression of MAdCAM-1 in response to TNF-alpha, IL-1 beta and IFN-gamma was studied by immunoblotting. Lymphocyte adhesion was studied using alpha 4 beta 7 integrin expressing lymphocytes (TK-1) +/- anti-MAdCAM-1 mAb.


RESULTS
TNF-alpha induced MAdCAM-1 dose-and time-dependently with maximum expression at 20 ng/ml and at 48 hours. IL-1 beta also induced MAdCAM-1 to a lesser extent compared to TNF-alpha; IFN-gamma did not induce MAdCAM-1. TNF-alpha significantly increased lymphocyte-endothelial adhesion (P < 0.01), which was reversed by anti-MAdCAM-1 antibody. MAdCAM-1 expression was also reduced by N-acetylcysteine and by two NO donors (SperNO, DETANO) suggesting that hepatic endothelial MAdCAM-1 is oxidant and NO regulated.


CONCLUSIONS
MAdCAM-1 is a major determinant of leukocyte recruitment in chronic inflammation and is expressed by HEC in response to IL-1 beta and TNF-alpha. This system may provide a useful model for studying inflammatory mechanisms in liver disease and help determine if controlled MAdCAM-1 expression might influence inflammation in liver disease.
Ando
Tomoaki
T
Nagoya City Medical University, 1-Kawasumi-Mizuho, Nagoya, 467-8601, Japan. andytomo@hotmail.com
Langley
Robert R
RR
Wang
Yuping
Y
Jordan
Paul A
PA
Minagar
Alireza
A
Alexander
J Steven
JS
Jennings
Merilyn H
MH
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002478:Cells, Cultured; D016207:Cytokines / Q000502:physiology*; D004729:Endothelium, Lymphatic / Q000166:cytology / Q000378:metabolism*; D018836:Inflammation Mediators / Q000502:physiology*; D016023:Integrins / Q000502:physiology*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009088:Mucoproteins
D015815:Cell Adhesion Molecules; D016207:Cytokines; D018836:Inflammation Mediators; D016023:Integrins; C489082:Madcam1 protein, mouse; D009088:Mucoproteins; C071777:integrin alpha4beta7