c-Jun Triggers Apoptosis in Human Vascular Endothelial Cells

• Published in: Circulation research 1999-09, Vol.85 (5), p.387-393
• Main Authors: Wang, Nanping, Verna, Lynne, Hardy, Stephen, Zhu, Yi, Birrer, Michael J, Stemerman, Michael B
• Format: Article
• Language: English
• Subjects: Adenoviridae - genetics; Amino Acid Chloromethyl Ketones - pharmacology; Apoptosis - drug effects; Apoptosis - physiology; Biological and medical sciences; Blood vessels and receptors; Caspase 3; Caspase Inhibitors; Caspases - physiology; Cells, Cultured; Cysteine Proteinase Inhibitors - pharmacology; Cytomegalovirus - genetics; Endothelium, Vascular - cytology; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; Genes, jun; Genetic Vectors - genetics; Humans; Hydrogen Peroxide - pharmacology; Oligopeptides - pharmacology; Promoter Regions, Genetic; Proto-Oncogene Proteins c-jun - physiology; Recombinant Fusion Proteins - physiology; Tetracycline - pharmacology; Transcriptional Activation; Transfection; Umbilical Veins; Vertebrates: cardiovascular system
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/01.RES.85.5.387

In endothelial cells (ECs), the transcription factor c-Jun is induced by a variety of stimuli that perturb EC function. To extend our understanding of the role of c-Jun in EC physiology, we have directed overexpression of c-Jun in human umbilical vein ECs by using a tetracycline-regulated adenoviral expression system. In this study, we report a novel observation using this system. Specific expression of c-Jun is a sufficient trigger for ECs to undergo apoptosis, as demonstrated by a set of combined assays including an ELISA specific for histone-associated DNA fragmentation, DNA laddering, and TdT-mediated dUTP nick end labeling (TUNEL). Tetracycline can effectively shut off c-Jun overexpression and prevent EC apoptosis. Cleavage of poly(ADP-ribose) polymerase was also detected in ECs overexpressing c-Jun. Moreover, inhibitors of cysteine proteases blocked the apoptosis, suggesting a caspase-associated mechanism involved in proapoptotic effects of c-Jun. To gain further insight into the role of c-Jun as a pathophysiological regulator of EC death, TAM67, a dominant-negative mutant of c-Jun, was overexpressed in human umbilical vein ECs to abrogate endogenous c-Jun/activator protein-1 activation. H2O2-triggered apoptosis was largely attenuated in ECs overexpressing TAM67. Together, these results suggest that c-Jun, as a proapoptotic molecule, may play a role in mediating the cell death program in vascular endothelium.