Protein synthesis dependent and independent apoptosis of murine splenic T cells.
To elucidate the mechanism of apoptosis in matured T cells, we examined the effect of phorbol esters capable of activating protein kinase C, cAMP agonists, calcium ionophores, and dexamethasone on apoptosis in mouse splenic T cells. All of these agents induced apoptosis in thymocytes. Neither phorbol esters nor calcium ionophores induced apoptosis in the splenic T cells. Dibutyrylcyclic AMP induced apoptosis in splenic T cells but to a lesser extent than that in thymocytes. The results suggest that matured T cells are more resistant to various apoptogenic stimuli than thymocytes. Dexamethasone induced apoptotic cell death in splenic T cells as well as in thymocytes. Cycloheximide, an inhibitor of protein synthesis which completely inhibited thymocyte apoptosis, induced slight apoptosis in splenic T cells, but it inhibited the dexamethasone-induced apoptosis to a level at which cycloheximide induced apoptosis, indicating that at least two pathways of apoptosis exist in peripheral T cells; one protein synthesis dependent and the other independent. Taken together, the results suggest that the apoptosis of peripheral T cells is regulated by a mechanism different from that of thymocytes.
Nishimoto
Y
Y
Department of Biochemistry, School of Medicine, Tokyo Dental College, Chiba, Japan.
Onishi
Y
Y
Sato
Y
Y
Kizaki
H
H
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D053938:DNA Fragmentation / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D014176:Protein Biosynthesis; D011506:Proteins / Q000187:drug effects; D013154:Spleen / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D011506:Proteins