title: Influence of glutathione availability on cell damage induced by human immunodeficiency virus type 1 viral protein R.
abstract: The human immunodeficiency virus type 1 (HIV-1) encodes for accessory viral protein R (Vpr), which arrests the cell cycle of host cells at G2 and causes mitochondrial dysfunction and alterations in glycolysis. High-level expression of Vpr protein correlates with increased viral production and disease progression. Vpr causes structural and functional injury in many types of eukaryotic cells, whether or not they are permissive for viral replication; among them is the budding yeast Saccharomyces cerevisiae. We hypothesized that the dramatic Vpr-induced injuries in yeast could be prevented by strengthening their redox response capacity. We show that exogenous addition of glutathione (GSH) or its prodrug, N-acetylcysteine (NAC), protected budding yeasts from Vpr-induced cytopathic effects. Moreover, addition of adenosine triphosphate (ATP) to growing cultures of Vpr-producing yeast returned cellular growth to control levels, whereas the addition dehydroascorbic acid (DHA) had only a minor protective effect. The diminished protein levels of Cox2p and Cox4p in wild typeVpr-producing yeasts together with the acute sensitivity of petite yeasts to Vpr activity may have been caused by low intracellular ATP levels. As a consequence of this energy deficit, eukaryotic cells would be unable to synthetize adequate supplies of GSH or to signal the mitochondrial retrograde response. Our findings strongly suggest that the cytopathogenic effect of Vpr protein in eukaryotic cells can be prevented by increasing intracellular antioxidant stores or, alternatively, supplying external ATP. Furthermore, these results support a potentially promising future for S. cerevisiae expression as a modality to search for Vpr-targeted inhibitors.
authors.affiliation: Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Noemí
authors.initials: N
authors.lastname: Monroy
authors.affiliation: Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Herrero
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Carrasco
authors.affiliation: Unidad de Expresión Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Carretera de Majadahonda-Pozuelo Km 2, 28220 Majadahonda, Madrid, Spain. Electronic address: megonzalez@isciii.es.
authors.forename: María Eugenia
authors.initials: ME
authors.lastname: González
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D018384:Oxidative Stress; D004718:Saccharomycetales / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D054325:vpr Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*
chemical_list: D054325:vpr Gene Products, Human Immunodeficiency Virus; C514912:vpr protein, Human immunodeficiency virus 1; D000255:Adenosine Triphosphate; D005978:Glutathione
keywords: HIV-1; Heterologous expression; Oxidative stress; Phenotypic analysis; Therapeutic target; Vpr