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Primate blood signs of arenavirus hemorrhagic fever

ABSTRACT: 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 We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Keywords: time course

ORGANISM(S): Homo sapiens Macaca mulatta

PROVIDER: GSE5790 | GEO | 2007/09/01

SECONDARY ACCESSION(S): PRJNA97149

REPOSITORIES: GEO

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Project description: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; We used microarrays to detail the global programme of gene expression underlying cellularisation and identified distinct classes of up-regulated genes during this process. Experiment Overall Design: Rhesus macaques inoculated with a lethal dose of LCMV-WE were used to model human infection with Lassa fever virus (Lukashevich et al 2002, 2003; Rodas et al 2004). To identify molecular events that occur during the first few days of virus exposure, we monitored gene expression in peripheral blood mononuclear cell (PBMC) samples by microarray analysis. Approximately 150 samples from 23 different rhesus macaques (Table 1) were hybridized to Affymetrix U133 chips. Experiment Overall Design: Affymetrix U133 arrays cover the entire human genome with approximately 54,000 gene fragments representing approximately 22,000 genes. The use of these human arrays for macaque transcriptome analysis has been validated by other laboratories (Ace et al, 2004 Wang et al, 2004), i.e. 99.8% of the array elements for which human DNA gave a signal >1.4-fold over background were also >1.4 over background for macaque DNA (Rubins et al, 2004). LCMV-infected blood samples were compared to uninfected controls and genes with over two-fold change in expression were designated âdifferentially expressedâ (Fig. 1). Thus, out of 54,000 elements, 8410 (16%) were differentially regulated with a >2-fold change in expression [supplementary Table 1 has these genes in order of the magnitude of their differential expression]. Experiment Overall Design: Virus was detectable in these monkeys at day 4 after infection by plaque assay and by RT-PCR of blood cDNA (Djavani et al 2005). Although virus is replicating in monocytes, endothelial cells, liver, spleen, and peripheral lymphoid organs soon after inoculation (Rai et al, 1997; Lukashevich et al, 2002), virus is not detectable in the circulation for the first three days. Thus we define the early, pre-viremic stage as days 1-3, and a later viremic stage as days 4-7. Although the LCMV-Armstrong strain replicated as well in cell culture as LCMV-WE, the LCMV-Arm-infected monkeys did not experience viremia, i.e. viral nucleic acid were detected in tissues but virus loads were not high enough to be detected in the circulation. The Arm-infected monkeys resisted a lethal challenge with LCMV-WE, further confirming that they had been productively infected (Rodas et al, 2004). An overview of gene expression in monkeys shows a trend to down-regulate genes at the onset of viremia followed by a sharp increase in up-regulated genes. Those monkeys that did not experience viremia (Armstrong-infected) showed no dramatic down-regulation trend (Fig. 1). Over the entire study period of 7 days, the number of down-regulated genes in the WE-infected macaques was significantly more than the number seen in the Arm-infected monkeys (p < 0.005).

Project description:Rhesus 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. 6 groups: uninfected controls, LCMV-WE infected (pre-viremic; day 1 to day 3), LCMV-WE infected (viremic; day 4 to day 7), LCMV-WE infected (post-viremic; day 8 to day 12), LCMV-Armstrong (LCMV-ARM; non-virulent strain) infected, and LCMV-ARM/LCMV-WE infected but not diseased. Each sample is from the liver of a different rhesus macaque.

Project description:Lassa fever (LF) is a rodent-borne viral disease that can be fatal for human beings. In this study, an attenuated Lassa vaccine candidate, ML29, was tested in SIV-infected rhesus macaques for its ability to elicit immune responses without instigating signs of virulent disease. ML29 is a reassortant between Lassa and Mopeia viruses that causes a transient infection in non-human primates and confers sterilizing protection from lethal Lassa viral challenge. However, since the LF endemic area of West Africa also has high HIV seroprevalence, it is important to determine whether vaccination could be safe in the context of AIDS. SIV-infected and uninfected rhesus macaques were vaccinated with the ML29 virus and monitored for classical and non-classical signs of arenavirus disease. Classical disease signs included viremia, rash, weight loss, high liver enzyme levels, and virus invasion of the central nervous system. Non-classical signs derived from profiling the blood transcriptome of virulent and non-virulent arenavirus infections included increased expression of interferon response genes and decreased expression of COX2, IL-1?, coagulation intermediates and nuclear receptors needed for stress signaling. Here it is demonstrated that SIV-infected and uninfected rhesus macaques responded similarly to ML29 vaccination, and that none developed signs of arenavirus disease or persistence. Furthermore, 5 of 5 animals given a heterologous challenge with a lethal dose of LCMV-WE survived without developing disease signs. 30 RNA samples from Monkey PBMC: 4 uninf. Monkey PBMC, 8 SIV-infected Monkey PBMC(From 8 Monkeys), 5 SIV+ML29-sc infected week1(Monkey PBMC), 5 SIV+ML29-sc infected week2(Monkey PBMC), 1 SIV+ML29-ig infected week1(Monkey PBMC), 1 SIV+ML29-ig infected week2(Monkey PBMC), 2 SIV+Arm-sc infected week1(Monkey PBMC), 2 SIV+Arm-sc infected week2(Monkey PBMC), 1 only ML29-iv infected week1(Monkey PBMC), 1 only ML29-iv infected week2(Monkey PBMC)

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Primate blood signs of arenavirus hemorrhagic fever

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