Activation of Intrinsic and Extrinsic Proapoptotic Signaling Pathways in Interleukin-18-mediated Human Cardiac Endothelial Cell Death
| Autor: | Kirankumar Vemula, Liselotte E. Jensen, Srinivas Mummidi, Laurie B. Owen-Schaub, Bysani Chandrasekar, Rama Mohan Surabhi, Min Li-Weber |
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| Rok vydání: | 2004 |
| Předmět: |
Programmed cell death
Time Factors Blotting Western Immunoblotting bcl-X Protein Down-Regulation Apoptosis Enzyme-Linked Immunosorbent Assay Cell Separation IκB kinase Biology Biochemistry Proinflammatory cytokine Annexin Humans RNA Messenger Luciferases Molecular Biology Cells Cultured Genes Dominant Inflammation Cell Death Tumor Necrosis Factor-alpha Myocardium Interleukin-18 NF-kappa B DNA Cell Biology Oligonucleotides Antisense Flow Cytometry Mitochondria Up-Regulation Cell biology Enzyme Activation Endothelial stem cell Proto-Oncogene Proteins c-bcl-2 Tumor necrosis factor alpha Endothelium Vascular Signal transduction Interleukin-1 Protein Binding Signal Transduction |
| Zdroj: | Journal of Biological Chemistry. 279:20221-20233 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m313980200 |
| Popis: | Endothelial cells are the primary targets of circulating immune and inflammatory mediators. We hypothesize that interleukin-18, a proinflammatory cytokine, induces endothelial cell apoptosis. Human cardiac microvascular endothelial cells (HCMEC) were treated with interleukin (IL) 18. mRNA expression was analyzed by ribonuclease protection assay, protein levels by immunoblotting, and cell death by enzyme-linked immunosorbent assay and fluorescence-activated cell sorter analysis. We also investigated the signal transduction pathways involved in IL-18-mediated cell death. Treatment of HCMEC with IL-18 increases 1) NF-kappaB DNA binding activity; 2) induces kappaB-driven luciferase activity; 3) induces IL-1beta and TNF-alpha expression via NF-kappaB activation; 4) inhibits antiapoptotic Bcl-2 and Bcl-X(L); 5) up-regulates proapoptotic Fas, Fas-L, and Bcl-X(S) expression; 6) induces fas and Fas-L promoter activities via NF-kappaB activation; 7) activates caspases-8, -3, -9, and BID; 8) induces cytochrome c release into the cytoplasm; 9) inhibits FLIP; and 10) induces HCME cell death by apoptosis as seen by increased annexin V staining and increased levels of mono- and oligonucleosomal fragmented DNA. Whereas overexpression of Bcl-2 significantly attenuated IL-18-induced endothelial cell apoptosis, Bcl-2/Bcl-X(L) chimeric phosphorothioated 2'-MOE-modified antisense oligonucleotides potentiated the proapoptotic effects of IL-18. Furthermore, caspase-8, IKK-alpha, and NF-kappaB p65 knockdown or dominant negative IkappaB-alpha and dominant negative IkappaB-beta or kinase dead IKK-beta significantly attenuated IL-18-induced HCME cell death. Effects of IL-18 on cell death are direct and are not mediated by intermediaries such as IL-1beta, tumor necrosis factor-alpha, or interferon-gamma. Taken together, our results indicate that IL-18 activates both intrinsic and extrinsic proapoptotic signaling pathways, induces endothelial cell death, and thereby may play a role in myocardial inflammation and injury. |
| Databáze: | OpenAIRE |
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