title: Apoptosis induced by Oropouche virus infection in HeLa cells is dependent on virus protein expression.
abstract: Oropouche (OROV) is a single-stranded RNA arbovirus of the family Bunyaviridae, genus Orthobunyavirus, which has caused over half a million cases of febrile illness in Brazil in the past 30 years. OROV fever has been registered almost exclusively in the Amazon region, but global warming, deforestation and redistribution of vectors and animal reservoirs increases the risk of Oropouche virus emergence in other areas. OROV causes a cytolytical infection in cultured cells with characteristic cytopathic effect 48h post-infection. We have studied the mechanisms of apoptosis induced by OROV in HeLa cells and found that OROV causes DNA fragmentation detectable by gel electrophoresis and by flow cytometric analysis of the Sub-G1 population at 36h post-infection. Mitochondrial release of cytochrome C and activation of caspases 9 and 3 were also detected by western blot analysis. Lack of apoptosis induced by UV-inactivated OROV reveals that virus-receptor binding is not sufficient to induce cell death. Results obtained in cells treated with chloroquine and cycloheximide indicated that viral uncoating and replication are required for apoptosis induction by OROV. Furthermore, treatment of the cells with pan-caspase inhibitor prevented OROV-induced apoptosis without affecting virus progeny production. The results show that OROV infection in vitro causes apoptosis by an intracellular pathway involving mitochondria, and activated by a mechanism dependent on viral replication and protein synthesis.
authors.affiliation: Department of Cell and Molecular Biology, University of Sao Paulo School of Medicine, 3900, Av Bandeirantes, Ribeirão Preto, SP 14049-900, Brazil. gacrani@gmail.com, goacrani@usp.br
authors.forename: Gustavo Olszanski
authors.initials: GO
authors.lastname: Acrani
authors.forename: Rogério
authors.initials: R
authors.lastname: Gomes
authors.forename: José Luiz
authors.initials: JL
authors.lastname: Proença-Módena
authors.forename: Andrei Furlan
authors.initials: AF
authors.lastname: da Silva
authors.forename: Patricia Oliveira
authors.initials: PO
authors.lastname: Carminati
authors.forename: Maria Lucia
authors.initials: ML
authors.lastname: Silva
authors.forename: Rodrigo Ivo Marques
authors.initials: RI
authors.lastname: Santos
authors.forename: Eurico
authors.initials: E
authors.lastname: Arruda
mesh_terms: D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045304:Cytochromes c / Q000032:analysis; D003593:Cytoplasm / Q000737:chemistry; D053938:DNA Fragmentation; D006367:HeLa Cells; D006801:Humans; D016851:Orthobunyavirus / Q000472:pathogenicity*; D014764:Viral Proteins / Q000096:biosynthesis*; D037521:Virulence Factors / Q000096:biosynthesis*
chemical_list: D014764:Viral Proteins; D037521:Virulence Factors; D045304:Cytochromes c; D053148:Caspase 3; D053453:Caspase 9