RESUMO
Multiple sclerosis (MS) is an inflammatory, demyelinating disorder of the central nervous system that develops in genetically susceptible individuals. The majority of the MS-associated gene variants are located in genetic regions with importance for T-cell differentiation. Vitamin D is a potent immunomodulator, and vitamin D deficiency has been suggested to be associated with increased MS disease susceptibility and activity. In CD4+ T cells, we have analyzed in vitro vitamin D responsiveness of genes that contain an MS-associated single-nucleotide polymorphism (SNP) and with one or more vitamin D response elements in their regulatory regions. We identify IL2RA and TAGAP as novel vitamin D target genes. The vitamin D response is observed in samples from both MS patients and controls, and is not dependent on the genotype of MS-associated SNPs in the respective genes.
Assuntos
Linfócitos T CD4-Positivos/efeitos dos fármacos , Proteínas Ativadoras de GTPase/genética , Subunidade alfa de Receptor de Interleucina-2/genética , Esclerose Múltipla/genética , Receptores de Calcitriol/genética , Vitamina D/farmacologia , Adulto , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Feminino , Proteínas Ativadoras de GTPase/agonistas , Proteínas Ativadoras de GTPase/sangue , Expressão Gênica , Perfilação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Subunidade alfa de Receptor de Interleucina-2/antagonistas & inibidores , Subunidade alfa de Receptor de Interleucina-2/sangue , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/sangue , Esclerose Múltipla/patologia , Polimorfismo de Nucleotídeo Único , Cultura Primária de Células , Receptores de Calcitriol/sangue , Elementos de Resposta , Vitamina D/sangueRESUMO
Interferon stimulated genes (ISGs) target viruses at various stages of their infectious life cycles, including at the earliest stage of viral entry. Here we identify ArfGAP with dual pleckstrin homology (PH) domains 2 (ADAP2) as a gene upregulated by type I IFN treatment in a STAT1-dependent manner. ADAP2 functions as a GTPase-activating protein (GAP) for Arf6 and binds to phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) and PI(3,4)P2. We show that overexpression of ADAP2 suppresses dengue virus (DENV) and vesicular stomatitis virus (VSV) infection in an Arf6 GAP activity-dependent manner, while exerting no effect on coxsackievirus B (CVB) or Sendai virus (SeV) replication. We further show that ADAP2 expression induces macropinocytosis and that ADAP2 strongly associates with actin-enriched membrane ruffles and with Rab8a- and LAMP1-, but not EEA1- or Rab7-, positive vesicles. Utilizing two techniques--light-sensitive neutral red (NR)-containing DENV and fluorescence assays for virus internalization--we show that ADAP2 primarily restricts DENV infection at the stage of virion entry and/or intracellular trafficking and that incoming DENV and VSV particles associate with ADAP2 during their entry. Taken together, this study identifies ADAP2 as an ISG that exerts antiviral effects against RNA viruses by altering Arf6-mediated trafficking to disrupt viral entry.