Upregulation of the Suppressors of Cytokine Signaling 1 and 3 Is Associated with Arrest of Phosphorylated-STAT1 Nuclear Importation and Reduced Innate Response in Denguevirus-Infected Macrophages Tania Estrada-Jime ´ nez, 1,2 Lourdes Milla ´ n-Pe ´ rez Pen ˜ a, 2 Lilian Flores-Mendoza, 1 Virginia Seden ˜ o-Monge, 3 Gerardo Santos-Lo ´ pez, 1 Nora Rosas-Murrieta, 2 Sandra Reyes-Carmona, 2 Eli Tera ´ n-Cabanillas, 4 Jesus Herna ´ ndez, 4 Irma Herrera-Camacho, 2 Vero ´ nica Vallejo-Ruiz, 1 and Julio Reyes-Leyva 1 Abstract To clarify whether the suppressors of cytokine signaling (SOCS) are associated with denguevirus (DENV) evasion of the antiviral response, we analyzed the expression kinetics of SOCS1 and SOCS3 and of the antiviral genes MxA and OAS during DENV infection of U937 macrophages that were or not treated with interferon (IFN)-a. DENV infection produced a viral titer three times higher in untreated than in IFN-a-treated cells ( p < 0.001 at 72 h postinfection [p.i.]). Partial inhibition of DENV replication was associated with reduced expression of MxA and OAS antiviral genes as well as higher SOCS1 and SOCS3 expression in DENV-infected cells than in cells treated only with IFN-a. Complete loss of phosphorylated-signal transducer and activator of transcription (p-STAT)2 and reduced nuclear importation of p-STAT1 were observed in DENV-infected cells compared to IFN-a treatment that induced p-STAT1 and p-STAT2. Our data thus suggest that overexpression of SOCS1 and SOCS3 induced by DENV infection leads to impairment of antiviral response through the inhibition of STAT functionality. Introduction D engue is an acute viral disease that affects most tropical and subtropical regions of the world. The inci- dence of dengue has grown dramatically around the world in recent decades. It is estimated that 390 million (95% con- fidence interval 284–528) cases of dengue occur annually, of which 96 million (95% confidence interval 67–136) manifest clinically, 500,000 are severe, and 20,000 are fatal (6). Denguevirus (DENV) is an enveloped, single-stranded positive-sense RNA virus that belongs to the Flaviviridae family, genus Flavivirus, and is transmitted by mosquitoes of the Aedes egypti and Aedes albopictus species. Based on neutralization assay data, four serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) can be distinguished. The RNA ge- nome encodes a long precursor polyprotein containing three structural proteins (capsid [C], precursor membrane [prM], and envelope [E]) and seven nonstructural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5) (5). DENV causes the self-limited febrile illness dengue fever (DF), as well as the potentially lethal severe dengue disease (previously known as dengue hemorrhagic fever and dengue shock syndrome, DHF/DSS). Dengue is clini- cally characterized by the following: mild to high degree fever, retroorbital pain, headache, myalgia, arthralgia, rash, nausea, vomiting, abdominal pain, mucosal bleeding, and thrombocytopenia. In severe dengue organ dysfunc- tion, vascular permeability, plasma leakage, severe hem- orrhage, and shock can occur. The mechanism underlying endothelial cell dysfunction and plasma leakage is of pri- mary importance; however, it is far from being completely understood (5). Dengue pathogenesis can be partially explained through various hypotheses that implicate immune-related factors, including (i) antibody-dependent enhancement (ADE) of viral infection by non-neutralizing antibodies, (ii) activation of cross-reactive autoantibodies and T cells, and (iii) de- regulation of cytokine and complement cascades (16, 27). 1 Laboratorio de Virologı ´a y Biologı ´a Molecular, Centro de Investigacio ´n Biome ´dica de Oriente, HGZ5, Instituto Mexicano del Seguro Social, Metepec, Puebla, Me ´xico. 2 Laboratorio de Bioquı ´mica y Biologı ´a Molecular, Centro de Quı ´mica, Instituto de Ciencias, Beneme ´rita Universidad Auto ´noma de Puebla, Puebla, Me ´xico. 3 Departamento de Ciencias de la Salud, Universidad Popular Auto ´noma del Estado de Puebla, Puebla, Me ´xico. 4 Laboratorio de Inmunologı ´a, Centro de Investigacio ´n en Alimentacio ´n y Desarrollo A.C., Hermosillo, Sonora, Mexico. VIRAL IMMUNOLOGY Volume 29, Number 2, 2016 ª Mary Ann Liebert, Inc. Pp. 1–10 DOI: 10.1089/vim.2014.0136 1