Inhibition of inflammatory endothelial responses by a pathway involving caspase activation and p65 cleavage.
Suppression of NF kappa B activation has been involved in the elimination of survival programs during endothelial cell (EC) apoptosis. We used alpha-tocopheryl succinate (alpha-TOS) to trigger apoptosome formation and the subsequent activation of executioner caspases. The level of bcl-2 was reduced by alpha-TOS, and its downregulation potentiated and its overexpression suppressed pro-apoptotic effects of alpha-TOS, indicating a mitochondrial role in alpha-TOS-induced apoptosis in EC. alpha-TOS treatment was associated with induction of TUNEL-positive apoptosis in EC with a high but not with a low proliferation index. The use of the pan-caspase inhibitor z-VAD.fmk suggested the involvement of caspases in cleavage of p65, and in inhibition of nuclear translocation of p65 and NF kappa B-dependent transactivation of a gene construct encoding the green fluorescence protein elicited by TNF alpha in contact-arrested EC. The suppression by alpha-TOS of inflammatory EC responses induced by TNF alpha such as VCAM-1 mRNA and surface protein expression and shear-resistant arrest of monocytic cells were also reversed by z-VAD.fmk. NF kappa B-dependent transactivation was preserved in alpha-TOS-treated EC stably transfected with a caspase-noncleavable p65 mutant but not with its truncated form, thus establishing a direct link between alpha-TOS-induced effects and p65 cleavage. Our data infer a pathway by which caspase activation in EC inhibits NF kappa B-dependent inflammatory activation and monocyte recruitment, and provide evidence for a relationship between pro-apoptotic and anti-inflammatory pathways.
Neuzil
J
J
Institute for Prevention of Cardiovascular Diseases, Ludwig Maximilians University, Munich, Germany. jneuzil@klp.med.uni-muenchen.de
Schröder
A
A
von Hundelshausen
P
P
Zernecke
A
A
Weber
T
T
Gellert
N
N
Weber
C
C
D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D053178:Caspase 6; D020169:Caspases / Q000378:metabolism* / Q000502:physiology; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D007249:Inflammation / Q000201:enzymology / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D024505:Tocopherols; D051996:Transcription Factor RelA; D015533:Transcriptional Activation / Q000187:drug effects; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology
D016328:NF-kappa B; D051996:Transcription Factor RelA; D019010:Vascular Cell Adhesion Molecule-1; D014810:Vitamin E; C505407:CASP3 protein, human; C505514:CASP6 protein, human; D053148:Caspase 3; D053178:Caspase 6; D020169:Caspases; D024505:Tocopherols