Trauma-hemorrhage inhibits splenic dendritic cell proinflammatory cytokine production via a mitogen-activated protein kinase process.
Although splenic dendritic cell (DC) functions are markedly altered following trauma-hemorrhage, the mechanism(s) responsible for the altered DC functions remains unknown. We hypothesized that trauma-hemorrhage inhibits DC function via suppressing toll-like receptor 4 (TLR4) expression and mitogen-activated protein kinases (MAPKs). To examine this, male C3H/HeN (6-8 wk) mice were randomly assigned to sham operation or trauma-hemorrhage. Trauma-hemorrhage was induced by midline laparotomy and approximately 90 min of hypotension [blood pressure (BP) 35 mmHg], followed by fluid resuscitation (4x the shed blood volume in the form of Ringer lactate). Two hours later, mice were euthanized, splenic DCs were isolated, and the changes in their MAPK activation, TLR4-MD-2 expression, and ability to produce cytokines were measured. The results indicate that trauma-hemorrhage downregulated the lipopolysaccharide (LPS)-induced MAPK activation in splenic DCs. In addition to the decrease in MAPK activation, surface expression of TLR4-MD-2 was suppressed following trauma-hemorrhage. Furthermore, LPS-induced cytokine production from splenic DCs was also suppressed following trauma-hemorrhage. These findings thus suggest that the decrease in TLR4-MD-2 and MAPK activation may contribute to the LPS hyporesponsiveness of splenic DCs following trauma-hemorrhage. Hyporesponsiveness of splenic DCs was also found after stimulation with the TLR2 agonist zymosan. Our results may thus explain the profound immunosuppression that is known to occur under those conditions.
Kawasaki
Takashi
T
Center for Surgical Research, Univ. of Alabama at Birmingham, 1670 Univ. Blvd., Volker Hall, Rm. G094, Birmingham, AL 35294-0019, USA.
Choudhry
Mashkoor A
MA
Schwacha
Martin G
MG
Fujimi
Satoshi
S
Lederer
James A
JA
Bland
Kirby I
KI
Chaudry
Irshad H
IH
D000005:Abdomen / Q000601:surgery; D000007:Abdominal Injuries / Q000150:complications* / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation; D004789:Enzyme Activation; D006470:Hemorrhage / Q000209:etiology / Q000378:metabolism*; D018836:Inflammation Mediators / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D051218:Lymphocyte Antigen 96 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013154:Spleen / Q000187:drug effects / Q000201:enzymology / Q000276:immunology / Q000378:metabolism*; D013997:Time Factors; D051195:Toll-Like Receptor 2 / Q000819:agonists; D051197:Toll-Like Receptor 4 / Q000378:metabolism; D015054:Zymosan / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D047428:Protein Kinase Inhibitors; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C440499:lipopolysaccharide, Escherichia coli O111 B4; D015054:Zymosan; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases