Fas (CD95)- and tumor necrosis factor-mediated apoptosis in liver endothelial cells: role of caspase-3 and the p38 MAPK.
Recently, we showed that TNF enhances the susceptibility of endothelial cells from murine liver sinusoids (LEC) to Fas-mediated apoptosis, suggesting that signals transduced by Fas and TNF receptors may synergistically increase intracellular death signals in these cells. In this work we evaluated whether caspase-3 and p38 are involved in LEC apoptosis induced by Fas and TNF. Here we show that LEC treated with Fas agonist (Jo2 mAb at 0.1 microg/ml) and TNF had a greater caspase-3 activity (twofold increase) than cells treated with each factor alone. There was a strong correlation between caspase-3 activity and cell killing induced by Jo2/TNF, indicating that this caspase plays a critical role in this process. Likewise, there was a significant increase in caspase-8 activity in LEC treated with Jo2 and TNF, compared with untreated cells or cells treated with each factor alone. Apoptosis of LEC induced by Jo2/TNF was partially reversed by SB203580, a p38 inhibitor, suggesting that p38 is involved in apoptosis of these cells. To our knowledge, this is the first report that apoptosis induced by Fas/TNF in LEC is associated with coactivation of both caspase-3 and p38. Potentially, both caspase-3 and p38 may be of great importance in endothelial cell pathology as molecular targets for preventing vascular damage due to endothelial cell apoptosis.
Cardier
José E
JE
Laboratorio de Patología Celular y Molecular, Centro de Medicina Experimental, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela. jcardier@medicine.ivic.es
Erickson-Miller
Connie L
CL
D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000096:biosynthesis / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D007093:Imidazoles / Q000494:pharmacology; D008099:Liver / Q000166:cytology* / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D019014:fas Receptor / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases
D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; C093642:SB 203580