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Structure-activity relationships in glucocorticoid-induced apoptosis in T lymphocytes
M Perrin-Wolff1, J Bertoglio, B Bressac
1Laboratoire d'Immunotoxicologie, Faculté de Pharmacie Paris XI, Châtenay Malabry, France.
Biochemical Pharmacology
|June 29, 1995
Summary
Structural differences in glucocorticoids affect their ability to induce apoptosis in T-cells. Dexamethasone is more potent in CTLL-2 cells, unlike thymocytes, highlighting cell-specific responses.
Area of Science:
- Immunology
- Cell Biology
- Pharmacology
Background:
- Glucocorticoids are potent regulators of immune cell function, including apoptosis.
- T-cell apoptosis is crucial for immune homeostasis and preventing autoimmunity.
- Interleukin-2 (IL-2) is a key cytokine for T-cell survival and proliferation.
Purpose of the Study:
- To investigate the differential effects of glucocorticoids on apoptosis in T-cell models.
- To elucidate the role of structural variations in glucocorticoids on apoptosis induction.
- To explore the involvement of calcium and IL-2 in glucocorticoid-induced T-cell apoptosis.
Main Methods:
- Studied apoptosis in murine CTLL-2 T-cell line and primary thymocytes.
- Compared the apoptosis-inducing efficacy of dexamethasone, betamethasone, and triamcinolone.
- Utilized inhibitors of transcription, translation, and endonuclease.
- Investigated the role of calcium using EGTA.
- Assessed the protective effect of IL-2 against glucocorticoid-induced apoptosis.
Main Results:
- Dexamethasone was more potent in inducing apoptosis in CTLL-2 cells compared to betamethasone and triamcinolone.
- No significant difference in apoptosis induction was observed among the three glucocorticoids in thymocytes.
- Glucocorticoid-induced apoptosis was mediated by the glucocorticoid receptor and required transcription, translation, and endonuclease activity.
- Calcium played a differential role: apoptosis occurred in CTLL-2 cells with EGTA but was prevented in thymocytes.
- Higher IL-2 concentrations were needed to protect CTLL-2 cells from dexamethasone-induced apoptosis.
Conclusions:
- Structural differences at position 16 of the steroid nucleus correlate with varying apoptosis-inducing activity of glucocorticoids.
- This differential activity is cell-specific, being evident in the calcium-independent CTLL-2 model but not in thymocytes.
- Calcium and IL-2 modulate glucocorticoid-induced apoptosis differently in distinct T-cell populations.