Inhibition of type 4 cyclic nucleotide phosphodiesterase blocks intracellular TLR signaling in chronic lymphocytic leukemia and normal hematopoietic cells.
J Immunol
; 194(1): 101-12, 2015 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-25416804
ABSTRACT
A subset of chronic lymphocytic leukemia (CLL) BCRs interacts with Ags expressed on apoptotic cells, suggesting that CLL BCRs have the potential to internalize apoptotic cell RNA- or DNA-containing fragments with resultant activation of TLR7 or TLR9, respectively. By blocking cAMP degradation, type 4 cAMP phosphodiesterase (PDE4) inhibitors activate cAMP-mediated signaling and induce apoptosis in CLL cells. In this study, we show that autologous irradiated leukemic cells induce proliferation in CLL cells and that such proliferation is blocked by a TLR7/8/9 inhibitor, by DNase, and by the PDE4 inhibitor rolipram. Rolipram also inhibited CLL cell proliferation induced by synthetic TLR7 and TLR9 agonists, as well as TLR agonist-induced costimulatory molecule expression and TNF-a (but not IL-6 or IL-10) production. Whereas treatment with a TLR9 agonist protected IgH V region unmutated, but not mutated, CLL cells from apoptosis, PDE4 inhibitors augmented apoptosis in both subtypes, suggesting that cAMP-mediated signaling may abrogate a TLR9-mediated survival signal in prognostically unfavorable IGHV unmutated CLL cells. Rolipram inhibited both TLR7/8- and TLR9-induced IFN regulatory factor 5 and NF-kB p65 nuclear translocation. PDE4 inhibitors also blocked TLR signaling in normal human immune cells. In PBMC and CD14-positive monocytes, PDE4 inhibitors blocked IFN-a or TNF-a (but not IL-6) production, respectively, following stimulation with synthetic TLR agonists or RNA-containing immune complexes. These results suggest that PDE4 inhibitors may be of clinical utility in CLL or autoimmune diseases that are driven by TLR-mediated signaling.
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
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Tipos_de_cancer
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Leucemia
Base de dados:
MEDLINE
Assunto principal:
Leucemia Linfocítica Crônica de Células B
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Rolipram
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Nucleotídeo Cíclico Fosfodiesterase do Tipo 4
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Inibidores da Fosfodiesterase 4
Tipo de estudo:
Prognostic_studies
Limite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
J Immunol
Ano de publicação:
2015
Tipo de documento:
Article