CD4 +CD8 + thymocytes are induced to cell death by a small dose of puromycin via ER stress

• Published in: Cellular immunology 2009, Vol.260 (1), p.21-27
• Main Authors: Oguma, Takemi, Ono, Takeshi, Kajiwara, Toshimitsu, Sato, Masaki, Miyahira, Yasushi, Arino, Hiroshi, Yoshihara, Yasuo, Tadakuma, Takushi
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Apoptosis - drug effects; Apoptosis - genetics; bcl-X Protein - genetics; CD4 +CD8 + thymocytes; CD4 Antigens - immunology; CD8 Antigens - immunology; Cell Line; Dexamethasone - administration & dosage; Drug Synergism; Endoplasmic Reticulum - drug effects; ER stress; Flow Cytometry; Genes, bcl-2; Glucocorticoids - administration & dosage; Heat-Shock Proteins - metabolism; Mice; Protein Synthesis Inhibitors - administration & dosage; Puromycin; Puromycin - administration & dosage; Reverse Transcriptase Polymerase Chain Reaction; T-Lymphocyte Subsets - drug effects; T-Lymphocyte Subsets - immunology; Transfection
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/j.cellimm.2009.07.002

When the CD4 +CD8 + thymic lymphoma cells were treated with puromycin, we found that most of the cells died at 0.3–1 μg/ml of puromycin within 24 h. However, cell death was greatly reduced when the dose of puromycin was increased. Similar dose-pattern of cell death was observed in thymocytes and the sensitivity to puromycin was greater in CD4 +CD8 + thymocytes than CD4 +CD8 − thymocytes. The induction of apoptosis was blocked by the protein synthesis inhibitor cycloheximide, and to some extent by transfection of Bcl-xL or Bcl-2 genes. Expression of GRP78 was up-regulated after treatment with a small dose of puromycin, and the cell death by puromycin was blocked in the presence of caspase 12 inhibitor. These results indicated that the induction of cell death by low-dose puromycin was due to endoplasmic reticulum stress. Furthermore, we found that dexamethasone, a synthetic glucocorticoid, and puromycin worked synergistically to induce cell death in thymocytes.