Chikungunya triggers an autophagic process which promotes viral replication
Autor(es): Krejbich-Trotot Pascale, Gay Bernard, Li-Pat-Yuen Ghislaine, Hoarau Jean-Jacques, Jaffar-B-jee Marie-Christine, Briant Laurence, Gasque Philippe, Denizot Mélanie
Resumo: Chikungunya Virus (ChikV) surprised by a massive re-emerging outbreak in Indian Ocean in 2006, reaching Europe in 2007 - exhibited exceptional severe physiopathology in infants - elderly patients. In this context, it is important to analyze the innate immune host responses triggered against ChikV. Autophagy has been shown to be an important component of the innate immune response - is involved in host defense elimination of different pathogens. However, the autophagic process was recently observed to be hijacked by virus for their own replication. Here we provide the first evidence that hallmarks of autophagy are specifically found in HEK.293 infected cells - are involved in ChikV replication. To test the capacity of ChikV to mobilize the autophagic machinery, we performed fluorescence microscopy experiments on HEK.GFP.LC3 stable cells, - followed the LC3 distribution during the time course of ChikV infection. To confirm this, we performed electron microscopy on HEK.293 infected cells. To test the effect of ChikV-induced-autophagy on viral replication, we blocked the autophagic process, either by pharmacological (3-MA) or genetic inhibition (siRNA against the transcript of Beclin 1, an autophagic protein), - analyzed the percentage of infected cells - the viral RNA load released in the supernatant. Moreover, the effect of induction of autophagy by Rapamycin on viral replication was tested. The increasing number of GFP-LC3 positive cells with a punctate staining together with the enhanced number of GFP-LC3 dots per cell showed that ChikV triggered an autophagic process in HEK.293 infected cells. Those results were confirmed by electron microscopy analysis since numerous membrane-bound vacuoles characteristic of autophagosomes were observed in infected cells. Moreover, we found that inhibition of autophagy, either by biochemical reagent - RNA interference, dramatically decreases ChikV replication. Taken together, our results suggest that autophagy may play a promoting role in ChikV replication. Investigating in details the relationship between autophagy - viral replication will greatly improve our knowledge of the pathogenesis of ChikV - provide insight for the design of c-idate antiviral therapeutics.
Palavras-Chave: ChikV; Alphavirus; Autophagy; Innate immunity
Imprenta: Virology Journal v. 8, p. 432, 2011
Identificador do objeto digital: 10.1186/1743-422X-8-432
Descritores: Chikungunya virus - Biosynthesis ; Chikungunya virus - Cell ; Chikungunya virus - Immune response ; Chikungunya virus - Pathogenesis ; Chikungunya virus - Proteins ; Chikungunya virus - RNA ; Chikungunya virus - Immune response ; Chikungunya virus - Immunopathology ; Chikungunya virus - Viral infections ; Chikungunya Virus - Virus ; Chikungunya virus - Chikungunya fever ; Chikungunya virus - Epidemiology ; Chikungunya virus - Public health
Data de publicação: 2011
