The role of caspase 3 and BclxL in the action of interleukin 7 (IL-7): a survival factor in activated human T cells
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The effects of interleukin 7 (IL-7) on apoptosis in interleukin 2 (IL-2)-dependent, activated, primary, human T lymphocytes (hT cells) was examined. IL-7 (like IL-2) rescued cells from apoptosis, as measured by their cellular DNA profile and fragmentation. IL-2 also acted as a mitogen in these T cells. Both cytokines abrogated the dexamethasone-induced stimulation of Caspase 3 and prevented the cleavage of poly (ADP-ribose) polymerase (PARP), a substrate for the Caspase 3. IL-7 upregulated the expression of Bc1xL and counteracted the downregulation of this anti-apoptotic protein by the synthetic glucocorticoid, dexamethasone. Bcl-2 protein expression was uupregulated by IL-7 with or without dexamethasone, but Bc1-2 was expressed at a much lower level than BclxL in these cells. Levels of Bax did not markedly change on either cytokine stimulation or dexamethasone treatment. An unidentified 23-kDa band, which was recognized by the anti-Bc1-2 antibody, was induced by dexamthasone and suppressed by IL-7 and IL-2. This protein was subject to independent regulation as compared to the p26 Bc1-2 protein, suggesting that it may be a novel factor, possibly involved in the regulation of apoptosis. A clear role for IL-7 as a survival factor for cytokine withdrawal and glucocorticoid induced apoptosis in activated primary hT cells is implicated. In addition, regulation of BclxL and downstream inhibition of Caspase 3 activity may mediate this rescue signal.
Original language | English |
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Journal | Cytokine |
Volume | 10 |
Issue number | 9 |
Pages (from-to) | 662-8 |
Number of pages | 6 |
ISSN | 1043-4666 |
DOIs | |
Publication status | Published - 1998 |
Bibliographical note
Keywords: Apoptosis; Caspase 3; Caspases; Cell Survival; Cells, Cultured; Dexamethasone; Enzyme Activation; Gene Expression Regulation; Glucocorticoids; Humans; Interleukin-2; Interleukin-7; Lymphocyte Activation; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; T-Lymphocytes; bcl-X Protein
ID: 8545281