Tumor necrosis factor alpha signaling pathway and apoptosis in pancreatic β cells
| Autor: | Yoshiharu Tokuyama, Yasushi Saito, Jun-ichi Miyazaki, Katsumi Yamada, Hideichi Makino, Azuma Kanatsuka, Naotake Hashimoto, Yoshifumi Suzuki, Nobuko Ishizuka, Kazuo Yagui |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Ceramide
DNA damage Fas-Associated Death Domain Protein Endocrinology Diabetes and Metabolism Apoptotic nuclear changes Apoptosis DNA Fragmentation Ceramides Caspase 8 Receptors Tumor Necrosis Factor Islets of Langerhans Mice chemistry.chemical_compound Endocrinology Antigens CD Tumor Cells Cultured Animals Humans FADD Adaptor Proteins Signal Transducing biology Tumor Necrosis Factor-alpha Proteins TNF Receptor-Associated Factor 1 Molecular biology TRADD TNF Receptor-Associated Death Domain Protein Tumor Necrosis Factor Receptor-Associated Peptides and Proteins chemistry Receptors Tumor Necrosis Factor Type I biology.protein Tumor necrosis factor alpha Carrier Proteins Signal Transduction |
| Zdroj: | Metabolism. 48:1485-1492 |
| ISSN: | 0026-0495 |
| Popis: | Cytokines induce apoptosis in pancreatic beta cells, but the exact mechanisms and sequence of events are not clear. Here, we investigate a role for tumor necrosis factor alpha (TNF-alpha) in the apoptosis of beta cells. Using the ribonuclease (RNase) protection assay and the reverse transcriptase-polymerase chain reaction (RT-PCR) method, we confirmed that TNF receptor 1 (TNFR1), TNFR1-associated death domain protein (TRADD), Fas receptor-associated intracellular protein with death domain (FADD), and FADD-like interleukin-1beta-converting enzyme (FLICE) were expressed in the pancreatic beta cell line, MIN6 cells. Fluorescent microscopic examination using Hoechst 33342 dye (Sigma, St Louis, MO) demonstrated that TNF-alpha induced time- and dose-dependent apoptotic nuclear changes in these beta cells. In situ end-labeling (ISEL) DNA analysis revealed that 10 nmol/L TNF-alpha generated new 3'-OH DNA strand breaks. Moreover, qualitative assessment of the induced DNA damage on agarose gels showed that 10 nmol/L TNF-alpha produced characteristic apoptotic patterns of DNA fragments formed by internucleosomal hydrolysis of static chromatin. In addition, C2-ceramides and natural ceramides dispersed in a solvent mixture of ethanol and dodecane induced characteristic features of apoptosis in MIN6 cells, mimicking TNF-induced DNA damage. We also determined endosomal ceramide production after TNF-alpha (10 nmol/L) treatment in MIN6 cells using the diacylglycerol kinase assay. These results suggest that TNF-alpha can cause apoptosis in pancreatic beta cells through TNFR1-linked apoptotic factors, TRADD, FADD, and FLICE, and TNF-induced ceramide production may be involved in the pathways. |
| Databáze: | OpenAIRE |
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