Inhibition of vaccinia virus replication by adenosine in BSC-40 cells: involvement of A(2) receptor-mediated PKA activation.
In the present study, we show that adenosine (Ado) affects vaccinia virus (VV) replication in BSC-40 cells. In order to identify its effects on VV replicative cycle we analyzed the synthesis of virus macromolecules in cells incubated with 0.5 mM Ado. A 50% reduction in the steady-state level of virus DNA synthesis was observed. Consequently, virus post-replicative gene expression was also affected. A prolonged synthesis of the F11L early virus protein was also observed and it is likely related to a slow decline in the steady-state level of early mRNAs, as suggested by northern blot analysis of the VGF early transcript. The involvement of cAMP-signaling pathway as mediator of Ado response was also evaluated. Ado stimulated a three-fold increase in cAMP levels in BSC-40 cells and cAMP-mimetic agents reduced virus yield in a dose-dependent manner. Co-incubation of infected cells with H-89 reduced the inhibitory effects of 8-Br-cAMP and Ado on VV yields suggesting PKA involvement. A(2) receptor-mediated activation of PKA was indicated by antagonism of Ado response by theophylline and DMPX. Together, these results indicate that virus DNA replication is the main target of Ado. The mechanism involved is not related to reduction of the pyrimidine nucleotide synthesis. Furthermore, Ado-induced PKA activation modulates negatively an unidentified step of the virus replicative cycle.
Program of Neuroimmunology, Institute of Biology, Federal Fluminense University, Outeiro de São João Baptista, Niterói, Brazil. nissin@biof.ufrj.br
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Leão-Ferreira
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Paes-De-Carvalho
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De Mello
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Moussatché
D000241:Adenosine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002352:Carrier Proteins / Q000494:pharmacology; D002460:Cell Line; D018920:Coculture Techniques; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000378:metabolism / Q000821:virology; D047908:Intracellular Signaling Peptides and Proteins; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D015398:Signal Transduction; D013805:Theobromine / Q000031:analogs & derivatives* / Q000494:pharmacology; D013806:Theophylline / Q000494:pharmacology; D014616:Vaccinia virus / Q000187:drug effects* / Q000502:physiology; D014779:Virus Replication / Q000187:drug effects
D000998:Antiviral Agents; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D010726:Phosphodiesterase Inhibitors; D011500:Protein Synthesis Inhibitors; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; C015482:protein kinase modulator; C057837:3,7-dimethyl-1-propargylxanthine; D013806:Theophylline; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000241:Adenosine; D013805:Theobromine