Activation of the lipopolysaccharide signaling pathway in hepatic transplantation preservation injury.
BACKGROUND
Endotoxin or lipopolysaccharide (LPS) initiates a cascade of complications of septic shock and multiple organ failure seen in Gram-negative bacterial infections. The first step of this pathway, which leads to activated nuclear factor (NF)-kappaB, activating protein (AP)-1, and other transcription factors, is the formation of the LPS receptor complex by LPS, LPS-binding protein (LBP), CD14, and toll-like receptor (TLR) 2 or 4. We examined whether the LPS signaling pathway is activated by hepatic ischemia/reperfusion injury in the transplant setting.


METHODS
Orthotopic syngeneic rat liver transplantation was performed with 0 to 18 hr of cold preservation in University of Wisconsin solution. Animals were killed 1 to 48 hr after reperfusion. Northern blot analysis for CD14, LBP, and TLR2 mRNA, immunohistochemistry for LBP, liver enzyme analysis, and gel shift assay for NF-kappaB and AP-1 were performed.


RESULTS
LPS levels were elevated early after reperfusion. Aspartate aminotransferase and alanine aminotransferase maximally increased 12 hr after transplantation. LBP mRNA and protein and CD14 mRNA were significantly up-regulated peaking at 6 to 12 hr after reperfusion. TLR2 mRNA was also increased. NF-kappaB activity showed a biphasic peak at 1 to 3 hr and 12 hr after reperfusion, whereas AP-1 activity showed a peak at 3 to 6 hr. The induction of CD14 mRNA correlated with the length of cold ischemia time.


CONCLUSIONS
These data indicate that multiple components of the LPS signaling pathway are activated during ischemia/reperfusion injury after liver transplantation.
Tsoulfas
George
G
Department of Surgery, University of Pittsburgh, Starzl Transplantation Institute, Pennsylvania 15213, USA.
Takahashi
Yoshihito
Y
Ganster
Raymond W
RW
Yagnik
Gautam
G
Guo
Zhong
Z
Fung
John J
JJ
Murase
Noriko
N
Geller
David A
DA
D000209:Acute-Phase Proteins; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics; D003080:Cold Temperature; D029721:Drosophila Proteins; D015870:Gene Expression / Q000502:physiology; D018950:Lipopolysaccharide Receptors / Q000235:genetics; D008070:Lipopolysaccharides / Q000097:blood*; D008099:Liver / Q000737:chemistry / Q000502:physiology; D008111:Liver Function Tests; D016031:Liver Transplantation; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D011183:Postoperative Complications / Q000503:physiopathology; D011485:Protein Binding / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011917:Rats, Inbred Lew; D011956:Receptors, Cell Surface / Q000235:genetics; D015427:Reperfusion Injury / Q000503:physiopathology*; D015398:Signal Transduction / Q000502:physiology*; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D018808:Transcription Factor AP-1 / Q000378:metabolism; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D029721:Drosophila Proteins; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D018808:Transcription Factor AP-1; D000099231:Lipopolysaccharide-Binding Protein; C495343:Tlr2 protein, rat