Single point mutations in the helicase domain of the NS3 protein enhance dengue virus replicative capacity in human monocyte-derived dendritic cells and circumvent the type I interferon response.
Dengue is the most prevalent arboviral disease worldwide. The outcome of the infection is determined by the interplay of viral and host factors. In the present study, we evaluated the cellular response of human monocyte-derived DCs (mdDCs) infected with recombinant dengue virus type 1 (DV1) strains carrying a single point mutation in the NS3hel protein (L435S or L480S). Both mutated viruses infect and replicate more efficiently and produce more viral progeny in infected mdDCs compared with the parental, non-mutated virus (vBACDV1). Additionally, global gene expression analysis using cDNA microarrays revealed that the mutated DVs induce the up-regulation of the interferon (IFN) signalling and pattern recognition receptor (PRR) canonical pathways in mdDCs. Pronounced production of type I IFN were detected specifically in mdDCs infected with DV1-NS3hel-mutated virus compared with mdDCs infected with the parental virus. In addition, we showed that the type I IFN produced by mdDCs is able to reduce DV1 infection rates, suggesting that cytokine function is effective but not sufficient to mediate viral clearance of DV1-NS3hel-mutated strains. Our results demonstrate that single point mutations in subdomain 2 have important implications for adenosine triphosphatase (ATPase) activity of DV1-NS3hel. Although a direct functional connection between the increased ATPase activity and viral replication still requires further studies, these mutations speed up viral RNA replication and are sufficient to enhance viral replicative capacity in human primary cell infection and circumvent type I IFN activity. This information may have particular relevance for attenuated vaccine protocols designed for DV.
Laboratório De Virologia Molecular, Instituto Carlos Chagas, Curitiba, Brasil.
G F
GF
Silveira
Laboratório De Virologia Molecular, Instituto Carlos Chagas, Curitiba, Brasil.
D M
DM
Strottmann
Laboratório De Virologia Molecular, Instituto Carlos Chagas, Curitiba, Brasil.
L
L
de Borba
Laboratório De Imunobiologia, Universidade Federal De Santa Catarina, Trindade, Florianópolis, Brasil.
D S
DS
Mansur
Laboratório De Proteômica E Engenharia De Proteínas, Instituto Carlos Chagas, Curitiba, Brasil.
N I T
NI
Zanchin
Laboratório De Virologia Molecular, Instituto Carlos Chagas, Curitiba, Brasil.
J
J
Bordignon
Laboratório De Virologia Molecular, Instituto Carlos Chagas, Curitiba, Brasil.
C N Duarte
CN
dos Santos
D000251:Adenosine Triphosphatases / Q000378:metabolism; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000821:virology; D003715:Dengue / Q000276:immunology*; D053059:Dengue Vaccines / Q000276:immunology*; D003716:Dengue Virus / Q000502:physiology*; D006801:Humans; D057131:Immune Evasion; D007370:Interferon Type I / Q000378:metabolism; D046228:Microarray Analysis; D009000:Monocytes / Q000276:immunology; D017354:Point Mutation / Q000235:genetics; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics; D000085242:Viral Proteases
D000251:Adenosine Triphosphatases; D053059:Dengue Vaccines; D007370:Interferon Type I; D012697:Serine Endopeptidases; C504449:NS3 protease, dengue virus; D000085242:Viral Proteases
NS3 helicase; dendritic cells; dengue virus; type I IFN; viral replicative capacity