Interleukin-4 (IL-4) receptor expression on human T cells is affected by different intracellular signaling pathways and by IL-4 at transcriptional and posttranscriptional level.
Interleukin-4 (IL-4) modulates the survival, proliferation, and differentiation of a variety of hematopoietic cells. The effects are mediated through a single class of high-affinity receptors for IL-4. To understand the biologic effects of IL-4 on human T cells, we studied the regulation of IL-4 receptor (IL-4R) gene expression. We showed that IL-4R mRNA accumulation in human T cells is enhanced fourfold after activation of different secondary signaling pathways by concanavalin A (Con A), phorbol myristate acetate (PMA), the calcium ionophore A23187, and combinations of these factors. This could be ascribed to an increase in the IL-4R transcription rate and to stabilization of IL-4R mRNA resulting in a half-life of 80 to 90 minutes (v 35 to 40 minutes in resting T cells). IL-4 did enhance the IL-4R mRNA accumulation by a factor 10, which was caused by an increase in the IL-4R transcription rate and prolonging the half-life of IL-4R transcripts to 140 to 160 minutes. Finally, it was shown that A23187 induced IL-4R mRNA expression is a protein synthesis-dependent process. In contrast, Con A-, PMA-, Con A + PMA-, and Con A + A23187-induced expression of IL-4R mRNA is protein-synthesis independent. Cyclosporine A inhibited the A23187- and Con A + A23187-induced IL-4R mRNA accumulation, whereas Con A-, PMA-, and Con A + PMA-induced IL-4R mRNA expression was not affected by this drug. These data indicate that expression of IL-4 receptors on human T cells can be modulated by different intracellular signaling pathways at both transcriptional and posttranscriptional levels.
Dokter
W H
WH
Department of Medicine, University of Groningen, The Netherlands.
Borger
P
P
Hendriks
D
D
van der Horst
I
I
Halie
M R
MR
Vellenga
E
E
D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D016572:Cyclosporine / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D015847:Interleukin-4 / Q000378:metabolism / Q000494:pharmacology*; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*
D012333:RNA, Messenger; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen; D003208:Concanavalin A; D003609:Dactinomycin; D015847:Interleukin-4; D000001:Calcimycin; D016572:Cyclosporine; D003513:Cycloheximide; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium