Development and functional consequences of LPS tolerance in sinusoidal endothelial cells of the liver.
Kupffer cells and liver sinusoidal endothelial cells (LSEC) clear portal venous blood from gut-derived bacterial degradation products such as lipopolysaccharide (LPS) without inducing a local inflammatory reaction. LPS tolerance was reported for Kupffer cells, but little is known whether sensitivity of LSEC toward LPS is dynamically regulated. Here, we demonstrate that LSEC react to LPS directly as a function of constitutive Toll-like receptor 4 (TLR4)/CD14 expression but gain a LPS-refractory state upon repetitive stimulation without loss of scavenger activity. LPS tolerance in LSEC is characterized by reduced nuclear localization of nuclear factor-kappaB upon LPS rechallenge. In contrast to monocytes, however, TLR4 surface expression of LSEC is not altered by LPS stimulation and thus does not account for LPS tolerance. Mechanistically, LPS tolerance in LSEC is linked to prostanoid production and may account for cross-tolerance of LPS-treated LSEC to interferon-gamma stimulation. Functionally, LPS tolerance in LSEC results in reduced leukocyte adhesion following LPS rechallenge as a consequence of decreased CD54 surface expression. Furthermore, LPS tolerance is operative in vivo, as we observed by intravital microscopy-reduced leukocyte adhesion to LSEC and improved sinusoidal microcirculation in the liver after repetitive LPS challenges. Our results support the notion that LPS tolerance in organ-resident scavenger LSEC contributes to local hepatic control of inflammation.
Uhrig
Anja
A
Department of Transplant Surgery, University Mainz, Germany.
Banafsche
Ramin
R
Kremer
Michael
M
Hegenbarth
Silke
S
Hamann
Alf
A
Neurath
Markus
M
Gerken
Guido
G
Limmer
Andreas
A
Knolle
Percy A
PA
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000276:immunology*; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D007371:Interferon-gamma / Q000494:pharmacology; D007728:Kupffer Cells / Q000187:drug effects / Q000276:immunology; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology / Q000633:toxicity*; D008099:Liver / Q000098:blood supply* / Q000187:drug effects / Q000276:immunology*; D008297:Male; D051379:Mice; D008833:Microcirculation / Q000187:drug effects; D011453:Prostaglandins / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D011971:Receptors, Immunologic / Q000276:immunology*; D051197:Toll-Like Receptor 4
D008070:Lipopolysaccharides; D011453:Prostaglandins; D011971:Receptors, Immunologic; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma