Lassa fever virus is a zoonotic pathogen that plagues the endemic areas of West Africa. Rhesus macaques infected with a related arenavirus, LCMV-WE, serve as a model for Lassa-infection of human beings. Using a dose similar to that expected from a needle-stick, monkeys experience an early pre-viremic phase (day 1-3), a viremic phase with febrile onset (day 4-7), and, like human beings who succumb, they die within two weeks. Our goal was to monitor changes in gene expression that parallel disease progression in an effort to 1) identify genes with altered expression after infection, 2) identify genes that could discriminate between a virulent and non-virulent infection, and 3) identify genes encoding products that could serve as treatment targets for FDA-approved pharmaceuticals. Genes related to all three of these categories have been identified and some have been given preliminary validation by quantitative PCR and proteomic studies. These genes will be valuable candidates for future validation as prognostic biomarkers
Early blood profiles of virus infection in a monkey model for Lassa fever.
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View SamplesRhesus macaques (Macaca mulatta) infected with a lethal dose of lymphocytic choriomeningitis virus-strain WE (LCMV-WE) provide a model for Lassa fever virus infection of man. Like Lassa fever in human beings, disease begins with flu-like symptoms but can progress to morbidity fairly rapidly. Previously, we profiled the blood transcriptome of LCMV-infected monkeys (M. Djavani et al. J. Virol. 2007: PMID 17522210) showing distinct pre-viremic and viremic stages that discriminated between virulent and benign infections. In the present study, changes in liver gene expression from macaques infected with virulent LCMV-WE were compared to gene expression in uninfected monkeys as well as to monkeys that were infected but not diseased. We observed gene expression changes that occurred before the viremic stage of the disease, and could potentially serve as biomarkers that discriminate between exposure to a hemorrhagic fever virus and exposure to a benign virus. Based on a functional pathway analysis of differentially expressed genes, virulent LCMV-WE had a much broader effect on liver cell function than non-virulent virus. During the first few days of infection, virulent virus impacted gene expression associated with the generation of energy, such as fatty acid metabolism and glucose metabolism, with the complement and coagulation cascades, and with steroid metabolism, MAPK signaling and cell adhesion. For example, the energy profile resembled that of an organism entering starvation: acetyl-CoA carboxylase, a key enzyme of fatty acid synthesis, was shut down and gene products involved in gluconeogenesis were up-regulated. In conclusion, this study identifies several potential gene markers of LCMV-WE-associated liver disease and contributes to the database of gene expression changes correlated with LCMV pathogenesis in primates.
Gene expression in primate liver during viral hemorrhagic fever.
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