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Dexamethasone modulates TCR zeta chain expression and antigen receptor-mediated early signaling events in human T lymphocytes.

Abstract：

:Dexamethasone is a potent anti-inflammatory and immunosupressive agent that has complex, yet incompletely defined, effects on the immune response. Here, we explored the effect of dexamethasone on the expression of TCR zeta chain and TCR/CD3-induced early signaling events in human T lymphocytes. Immunoblotting studies using TCR zeta chain specific mAb showed a dose-dependent biphasic effect of dexamethasone on TCR zeta chain expression, that is, it was increased when cells were incubated with 10 nM, whereas the expression was decreased when incubated with 100 nM dexamethasone. The dose-dependent biphasic effect of dexamethsone on the TCR zeta chain expression was also revealed by FACS analysis of permeabilized cells. Time course studies showed that upregulation of the TCR zeta chain at 10 nM dexamethasone reached maximum levels at 24 h and remained elevated up to 48 h. Other subunits of the TCR/CD3 complex were minimally affected under these conditions. The increased expression of the TCR zeta chain following treatment with 10 nM dexamethasone correlated with increased anti-CD3 antibody-induced tyrosine phosphorylation of the TCR zeta chain and downstream signaling intermediate ZAP-70 and PLC gamma with faster kinetics. Similarly, the induction of TCR zeta chain expression at 10 nM dexamethasone correlated with increased and more sustained TCR/CD3-mediated [Ca(2+)](i) response. Reporter gene assays using TCR zeta chain promoter-driven luciferase gene constructs in Jurkat cells showed that treatment with 10 nM dexamethasone increased TCR zeta chain promoter activity and that the region between -160 and +58 was responsible for the observed effect. These results suggest that dexamethasone primarily acts at the transcriptional level and differentially modulates TCR zeta chain expression and antigen receptor-mediated early signaling events in human peripheral T lymphocytes.

journal_name

Cell Immunol

journal_title

Cellular immunology

authors

Nambiar MP,Enyedy EJ,Fisher CU,Warke VG,Juang YT,Tsokos GC

doi

10.1006/cimm.2001.1761

subject

Has Abstract

pub_date

2001-02-25 00:00:00

pages

62-71

issue

eissn

0008-8749

issn

1090-2163

pii

S0008-8749(01)91761-7

journal_volume

208

pub_type

杂志文章

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Dexamethasone modulates TCR zeta chain expression and antigen receptor-mediated early signaling events in human T lymphocytes.