Prostaglandin E2 differentially modulates IL-5 gene expression in activated human T lymphocytes depending on the costimulatory signal.
BACKGROUND
Protein kinase A (PKA) activation is documented to be inhibitory for T helper cell (T[H1])-like cytokines (IL-2, IFN-gamma), whereas T(H2)-like cytokines (IL-4, IL-5) are not affected or upregulated. We have recently shown that IL-4 gene expression can be inhibited by PKA activation but depends on the mode of T-cell activation. For IL-5 gene expression, we hypothesized that the mode of T-cell activation also determines the ultimate effect of simultaneous PKA activation.


OBJECTIVE
The objective of this study was the examination of IL-5 gene expression in healthy T cells activated with various mitogenic stimuli after simultaneous activation of PKA by dibutyryl-cAMP or prostaglandin E2 (PGE2).


METHODS
IL-5 mRNA was measured by semiquantitative reverse transcription-polymerase chain reaction or Northern analysis. IL-5 protein was measured by ELISA. Transcriptional mechanisms involved in IL-5 gene expression were determined by nuclear run-on experiments and electrophoretic mobility shift assays. Posttranscriptional mechanisms were determined by actinomycin D chase studies.


RESULTS
Anti-CD2-, anti-CD3-, and anti-CD3 plus anti-CD28-induced IL-5 mRNA were completely inhibited by dibutyryl cyclic AMP (10[-3] mol/L) and PGE2 (10[-5] mol/L), whereas concanavalin A-induced IL-5 mRNA was partially reduced. The effect of PGE2 was accomplished at the transcriptional level, probably as the result of inhibition of DNA binding of nuclear factor-kappaB. Anti-CD3 plus anti-CD28-induced IL-5 protein (504 +/- 56 pg/ml) was significantly reduced by PGE2 (122 +/- 42 pg/ml, p < 0.001). Addition of cytokines that use the IL-2 receptor gamma(C) chain (IL-2, IL-7, IL-15) abrogated the PGE2-induced inhibition of IL-5 protein. In contrast, concanavalin A plus PMA-induced IL-5 protein (75 +/- 8 pg/ml) was significantly upregulated by the simultaneous addition of PGE2 (128 +/- 17 pg/ml, p < 0.03).


CONCLUSIONS
PKA activation differentially modulates IL-5 gene expression and depends on the mode of T-cell activation.
Borger
P
P
Department of Internal Medicine, University of Groningen, The Netherlands.
Vellenga
E
E
Gringhuis
S I
SI
Timmerman
J A
JA
Lummen
C
C
Postma
D S
DS
Kauffman
H F
HF
D003994:Bucladesine / Q000494:pharmacology; D003208:Concanavalin A / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D015232:Dinoprostone / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D015848:Interleukin-5 / Q000096:biosynthesis* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects*; D008934:Mitogens / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology*; D013268:Stimulation, Chemical; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D004268:DNA-Binding Proteins; D015848:Interleukin-5; D008934:Mitogens; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D003208:Concanavalin A; D003994:Bucladesine; D004247:DNA; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate