title: Proteomic analysis of the secretome of HepG2 cells indicates differential proteolytic processing after infection with dengue virus.
abstract: Secretome analysis can be described as a subset of proteomics studies consisting in the analysis of the molecules secreted by cells or tissues. Dengue virus (DENV) infection can lead to a broad spectrum of clinical manifestations, with the severe forms of the disease characterized by hemostasis abnormalities and liver injury. The hepatocytes are a relevant site of viral replication and a major source of plasma proteins. Until now, we had limited information on the small molecules secreted by hepatic cells after infection by DENV. In the present study, we analysed a fraction of the secretome of mock- and DENV-infected hepatic cells (HepG2 cells) containing molecules with <10kDa, using different proteomic approaches. We identified 175 proteins, with 57 detected only in the samples from mock-infected cells, 59 only in samples from DENV-infected cells, and 59 in both conditions. Most of the peptides identified were derived from proteins larger than 10kDa, suggesting a proteolytic processing of the secreted molecules. Using in silico analysis, we predicted consistent differences between the proteolytic processing occurring in mock and DENV-infected samples, raising, for the first time, the hypothesis that differential proteolysis of secreted molecules would be involved in the pathogenesis of dengue.
  
  
  
  Since the liver, one of the targets of DENV infection, is responsible for producing molecules involved in distinct biological processes, the identification of proteins and peptides secreted by hepatocytes after infection would help to a better understanding of the physiopathology of dengue. Proteomic analyses of molecules with <10kDa secreted by HepG2 cells after infection with DENV revealed differential proteolytic processing as an effect of DENV infection.
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
authors.forename: Marjolly B
authors.initials: MB
authors.lastname: Caruso
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Laboratório de Toxinologia, Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ 21045-900, Brazil.
authors.forename: Monique R O
authors.initials: MR
authors.lastname: Trugilho
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
authors.forename: Luiza M
authors.initials: LM
authors.lastname: Higa
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Laboratório de Toxinologia, Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ 21045-900, Brazil.
authors.forename: André S
authors.initials: AS
authors.lastname: Teixeira-Ferreira
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Laboratório de Toxinologia, Departamento de Fisiologia e Farmacodinâmica, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ 21045-900, Brazil.
authors.forename: Jonas
authors.initials: J
authors.lastname: Perales
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
authors.forename: Andrea T
authors.initials: AT
authors.lastname: Da Poian
authors.affiliation: Rede Proteômica do Rio de Janeiro, Brazil; Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil. Electronic address: lzingali@bioqmed.ufrj.br.
authors.forename: Russolina B
authors.initials: RB
authors.lastname: Zingali
mesh_terms: D003715:Dengue / Q000378:metabolism; D003716:Dengue Virus; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000737:chemistry / Q000821:virology; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000821:virology; D059748:Proteolysis; D040901:Proteomics / Q000379:methods*
keywords: Dengue virus; Hepatic cells; Low molecular mass proteins; Prediction of proteolytic enzymes; Proteome; Secretome