Respiratory Syncytial Virus Persistence in Murine Macrophages Impairs IFN-β Response but Not Synthesis.
Type-I interferon (IFN-I) production is an early response to viral infection and pathogenic viruses have evolved multiple strategies to evade this cellular defense. Some viruses can establish and maintain persistent infections by altering the IFN-I signaling pathway. Here, we studied IFN-I synthesis and response in an in vitro model of persistent infection by respiratory syncytial virus (RSV) in a murine macrophage-like cell line. In this model, interferon regulatory factor 3 was constitutively active and located at nuclei of persistently infected cells, inducing expression of IFN-beta mRNA and protein. However, persistently infected macrophages did not respond in an autocrine manner to the secreted-IFN-beta or to recombinant-IFN-beta, since phosphorylated-STAT1 was not detected by western blot and transcription of the interferon-stimulated genes (ISGs) Mx1 and ISG56 was not induced. Treatment of non-infected macrophages with supernatants from persistently infected cells induced STAT1 phosphorylation and ISGs expression, mediated by the IFN-I present in the supernatants, because blocking the IFN-I receptor inhibited STAT1 phosphorylation. Results suggest that the lack of autocrine response to IFN-I by the host cell may be one mechanism for maintenance of RSV persistence. Furthermore, STAT1 phosphorylation and ISGs expression induced in non-infected cells by supernatants from persistently infected macrophages suggest that RSV persistence may trigger a proinflammatory phenotype in non-infected cells as part of the pathogenesis of RSV infection.
Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico (UNAM), Ciudad Universitaria, D.F. Mexico C.P. 04510, Mexico. evelynmicro@gmail.com.
Evelyn
E
Rivera-Toledo
Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico (UNAM), Ciudad Universitaria, D.F. Mexico C.P. 04510, Mexico. tgonzalezlaura@gmail.com.
Laura
L
Torres-González
Department of Microbiology and Parasitology, Faculty of Medicine, National Autonomous University of Mexico (UNAM), Ciudad Universitaria, D.F. Mexico C.P. 04510, Mexico. begomez@unam.mx.
Beatriz
B
Gómez
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D016899:Interferon-beta / Q000096:biosynthesis*; D008264:Macrophages / Q000821:virology*; D051379:Mice; D064547:Myxovirus Resistance Proteins / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012136:Respiratory Syncytial Viruses / Q000254:growth & development* / Q000302:isolation & purification*; D050794:STAT1 Transcription Factor / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis
C522693:ISG56 protein, mouse; C579070:Mx1 protein, mouse; D064547:Myxovirus Resistance Proteins; D012333:RNA, Messenger; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D014157:Transcription Factors; D016899:Interferon-beta
IFN-beta; IRF3; STAT1; respiratory syncytial virus; viral persistence