Tumor necrosis factor-alpha enhances Haemophilus somnus lipooligosaccharide-induced apoptosis of bovine endothelial cells.
Haemophilus somnus lipooligosaccharide (LOS)-induced apoptosis of bovine pulmonary artery endothelial cells has been shown previously to be dependent on caspase-8 activation. Activation of caspase-8 can occur via a death receptor-dependent mechanism (e.g., TNF-alpha binding to TNF-alpha receptor 1 (TNF-R1)). In this study, we tested the hypothesis that TNF-alpha can enhance LOS-induced apoptosis of bovine endothelial cells. Addition of exogenous recombinant human TNF-alpha alone failed to cause apoptosis, or enhance LOS-induced apoptosis, of bovine endothelial cells. However, blocking de novo protein synthesis by addition of cycloheximide significantly enhanced apoptosis of bovine endothelial cells by TNF-alpha, LOS or TNF-alpha and LOS in combination. Conversely, addition of soluble recombinant human (sTNF-R1) diminished LOS-induced apoptosis. Overall, these data suggest that LOS-mediated apoptosis may be due, in part, to activation of a TNR-R1-dependent death pathway.
Sylte
Matt J
MJ
Department of Pathobiological Sciences, University of Wisconsin, 4174 Veterinary Medicine Building, 2015 Linden Dr., Madison, WI 53706, USA.
Kuckleburg
Chris J
CJ
Leite
Fabio P
FP
Inzana
Thomas J
TJ
Czuprynski
Charles J
CJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects*; D044138:Haemophilus somnus / Q000502:physiology*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; C023023:lipid-linked oligosaccharides