A blood RNA transcriptome signature for COVID-19.

BACKGROUND: COVID-19 is a respiratory viral infection with unique features including a more chronic course and systemic disease manifestations including multiple organ involvement; and there are differences in disease severity between ethnic groups. The immunological basis for disease has not been fully characterised. Analysis of whole-blood RNA expression may provide valuable information on disease pathogenesis. METHODS: We studied 45 patients with confirmed COVID-19 infection within 10 days from onset of illness and a control group of 19 asymptomatic healthy volunteers with no known exposure to COVID-19 in the previous 14 days. Relevant demographic and clinical information was collected and a blood sample was drawn from all participants for whole-blood RNA sequencing. We evaluated differentially-expressed genes in COVID-19 patients (log2 fold change ≥ 1 versus healthy controls; false-discovery rate  0.05). CONCLUSIONS: The whole-blood transcriptome of COVID-19 has overall similarity with other respiratory infections but there are some unique pathways that merit further exploration to determine clinical relevance. The approach to a disease score may be of value, but needs further validation in a population with a greater range of disease severity

A universal genome sequencing method for rotavirus A from human fecal samples which identifies segment reassortment and multi-genotype mixed infection.

BACKGROUND: Genomic characterization of rotavirus (RoV) has not been adopted at large-scale due to the complexity of obtaining sequences for all 11 segments, particularly when feces are used as starting material. METHODS: To overcome these limitations, we developed a novel RoV capture and genome sequencing method combining commercial enzyme immunoassay plates and a set of routinely used reagents. RESULTS: Our approach had a 100% success rate, producing >90% genome coverage for diverse RoV present in fecal samples (Ct < 30). CONCLUSIONS: This method provides a novel, reproducible and comparatively simple approach for genomic RoV characterization and could be scaled-up for use in global RoV surveillance systems. TRIAL REGISTRATION (PROSPECTIVELY REGISTERED): Current Controlled Trials ISRCTN88101063 . Date of registration: 14/06/2012

Host Cell Transcriptome Profile during Wild-Type and Attenuated Dengue Virus Infection

10.1371/journal.pntd.0002107PLoS Neglected Tropical Diseases73

Chikungunya as a cause of acute febrile illness in southern Sri Lanka

10.1371/journal.pone.0082259PLoS ONE812-POLN

RNA Viruses, Pandemics and Anticipatory Preparedness

RNA viruses are likely to cause future pandemics and therefore we must create and organize a deep knowledge of these viruses to prevent and manage this risk. Assuming prevention will fail, at least once, we must be prepared to manage a future pandemic using all resources available. We emphasize the importance of having safe vaccine candidates and safe broad-spectrum antivirals ready for rapid clinical translation. Additionally, we must have similar tools to be ready for outbreaks of RNA viruses among animals and plants. Finally, similar coordination should be accomplished for other pathogens with pandemic potential

The Polypyrimidine Tract Binding Protein Is Required for Efficient Picornavirus Gene Expression and Propagation

Mammalian host factors required for efficient viral gene expression and propagation have been often recalcitrant to genetic analysis. A case in point is the function of cellular factors that trans-activate internal ribosomal entry site (IRES)-driven translation, which is operative in many positive-stranded RNA viruses, including all picornaviruses. These IRES trans-acting factors have been elegantly studied in vitro, but their in vivo importance for viral gene expression and propagation has not been widely confirmed experimentally. Here we use RNA interference to deplete mammalian cells of one such factor, the polypyrimidine tract binding protein, and test its requirement in picornavirus gene expression and propagation. Depletion of the polypyrimidine tract binding protein resulted in a marked delay of particle propagation and significantly decreased synthesis and accumulation of viral proteins of poliovirus and encephalomyocarditis virus. These effects could be partially restored by expression of an RNA interference-resistant exogenous polypyrimidine tract binding protein. These data indicate a critical role for the polypyrimidine tract binding protein in picornavirus gene expression and strongly suggest a requirement for efficient IRES-dependent translation

Production of Infectious Dengue Virus in <i>Aedes aegypti</i> Is Dependent on the Ubiquitin Proteasome Pathway

<div><p>Dengue virus (DENV) relies on host factors to complete its life cycle in its mosquito host for subsequent transmission to humans. DENV first establishes infection in the midgut of <i>Aedes aegypti</i> and spreads to various mosquito organs for lifelong infection. Curiously, studies have shown that infectious DENV titers peak and decrease thereafter in the midgut despite relatively stable viral genome levels. However, the mechanisms that regulate this decoupling of infectious virion production from viral RNA replication have never been determined. We show here that the ubiquitin proteasome pathway (UPP) plays an important role in regulating infectious DENV production. Using RNA interference studies, we show <i>in vivo</i> that knockdown of selected UPP components reduced infectious virus production without altering viral RNA replication in the midgut. Furthermore, this decoupling effect could also be observed after RNAi knockdown in the head/thorax of the mosquito, which otherwise showed direct correlation between infectious DENV titer and viral RNA levels. The dependence on the UPP for successful DENV production is further reinforced by the observed up-regulation of key UPP molecules upon DENV infection that overcome the relatively low expression of these genes after a blood meal. Collectively, our findings indicate an important role for the UPP in regulating DENV production in the mosquito vector.</p></div

Knockdown of UBE2A and DDB1 decouples infectious DENV2 production from viral RNA replication in mosquitoes.

<p>(A) In the infected midguts, virus titers declined significantly after knockdown of UBE2A and DDB1 at 6 dpbm. N = 12–16. Student’s t test, *p < 0.05. (B) In the infected midguts, no statistically significant differences were observed in DENV2 viral RNA levels 6 dpbm after gene knockdown. N = 12–16. (C) Ratio of midgut infectious titers to viral RNA levels 6 dpbm after gene knockdown. N = 12–16. Student’s t test, *p < 0.05. (D) In infected heads/thoraces (HT), virus titers at 8 days post intra-thoracic inoculation declined significantly after knockdown of UBE2A and DDB1. N = 8–10. Student’s t test, **p < 0.01, ***p<0.001. (E) In infected heads/thoraces (HT), no statistically significant differences were observed in DENV2 viral RNA levels after gene knockdown. N = 8–10. (F) Ratio of head/thorax (HT) infectious titers to viral RNA levels after gene knockdown 8 dpi. N = 12–16. Student’s t test, **p<0.01.</p

Ingestion of blood meal does not modulate gene expression of <i>UBE2A</i> and <i>DDB1</i>.

<p>Sugar fed and blood fed mosquitoes were harvested at different time-points and individual midguts were dissected for analyses. Gene expression levels for (A) <i>UBE2A</i> and (B) <i>DDB1</i> were measured using qRT-PCR and normalized to GAPDH. Expression levels of <i>UBE2A</i> and <i>DDB1</i> in blood fed mosquitoes remained consistently unchanged over the course of 14 days, whereas ingestion of a sugar meal increases expression levels of <i>UBE2A</i> and <i>DDB1</i> significantly until 8 days relative to the blood fed mosquitoes. Mean ± SEM. N = 12. Student’s t test, **p < 0.01, ***p<0.001, ****p<0.0001.</p

Characterization of DENV-2 replication in the midguts and heads/thoraces of <i>Ae</i>. <i>aegypti</i> following ingestion of an infectious blood meal.

<p>(A) In the midgut, viral titers increased linearly until 8 dpbm and declined thereafter. In contrast, viral RNA remained stable between 8 to 21 dpbm. Mean ± SEM, N = 8–10. (B) In the heads/thoraces (HT), the increase in both infectious particles and viral RNA are positively correlated over time. Viral RNA copy number increases with increasing viral titers. Mean ± SEM, N = 8–10. (C-D) A corresponding decrease in PFU/Copy number was observed in the midgut over time, with no significant change in the head/thorax (HT).</p