Activation of human and mouse Kupffer cells by lipopolysaccharide is mediated by CD14.
Upregulation of CD14 in Kupffer cells has been implicated in the pathogenesis of several forms of liver injury, including alcoholic liver disease. However, it remains unclear whether CD14 mediates lipopolysaccharide (LPS) signaling in this specialized liver macrophage population. In this series of experiments, we determined the role of CD14 in LPS activation of Kupffer cells by using several complementary approaches. First, we isolated Kupffer cells from human livers and studied the effects of anti-CD14 antibodies on LPS activation of these cells. Kupffer cells were incubated with increasing concentrations of LPS in the presence and absence of recombinant human LPS binding protein (LBP). With increasing concentrations of LPS, human Kupffer cell tumor necrosis factor-alpha (TNF-alpha) production (a marker for Kupffer cell activation) increased in a dose-dependent manner in the presence and absence of LBP. In the presence of anti-human CD14 antibodies, the production of TNF-alpha was significantly diminished. Second, we compared LPS activation of Kupffer cells isolated from wild-type and CD14 knockout mice. Kupffer cells from CD14 knockout mice produced significantly less TNF-alpha in response to the same amount of LPS. Together, these data strongly support a critical role for CD14 in Kupffer cell responses to LPS.
Su
Grace L
GL
Department of Veterans Affairs Medical Center, Ann Arbor, Michigan 48109, USA. gsu@umich.edu
Goyert
Sanna M
SM
Fan
Ming-Hui
MH
Aminlari
Alireza
A
Gong
Ke Qin
KQ
Klein
Richard D
RD
Myc
Andrzej
A
Alarcon
William H
WH
Steinstraesser
Lars
L
Remick
Daniel G
DG
Wang
Stewart C
SC
D000209:Acute-Phase Proteins; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D016466:CHO Cells; D002352:Carrier Proteins / Q000494:pharmacology; D002478:Cells, Cultured; D006224:Cricetinae; D005260:Female; D006801:Humans; D007728:Kupffer Cells / Q000187:drug effects* / Q000502:physiology*; D018950:Lipopolysaccharide Receptors / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008562:Membrane Glycoproteins; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout / Q000235:genetics; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D010738:Type C Phospholipases / Q000494:pharmacology; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D000906:Antibodies; D002352:Carrier Proteins; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D014409:Tumor Necrosis Factor-alpha; D010738:Type C Phospholipases; D000099231:Lipopolysaccharide-Binding Protein