Articles: coronavirus.
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Journal of virology · Aug 2015
A Kinome-Wide Small Interfering RNA Screen Identifies Proviral and Antiviral Host Factors in Severe Acute Respiratory Syndrome Coronavirus Replication, Including Double-Stranded RNA-Activated Protein Kinase and Early Secretory Pathway Proteins.
To identify host factors relevant for severe acute respiratory syndrome-coronavirus (SARS-CoV) replication, we performed a small interfering RNA (siRNA) library screen targeting the human kinome. Protein kinases are key regulators of many cellular functions, and the systematic knockdown of their expression should provide a broad perspective on factors and pathways promoting or antagonizing coronavirus replication. In addition to 40 proteins that promote SARS-CoV replication, our study identified 90 factors exhibiting an antiviral effect. Pathway analysis grouped subsets of these factors in specific cellular processes, including the innate immune response and the metabolism of complex lipids, which appear to play a role in SARS-CoV infection. Several factors were selected for in-depth validation in follow-up experiments. In cells depleted for the β2 subunit of the coatomer protein complex (COPB2), the strongest proviral hit, we observed reduced SARS-CoV protein expression and a >2-log reduction in virus yield. Knockdown of the COPB2-related proteins COPB1 and Golgi-specific brefeldin A-resistant guanine nucleotide exchange factor 1 (GBF1) also suggested that COPI-coated vesicles and/or the early secretory pathway are important for SARS-CoV replication. Depletion of the antiviral double-stranded RNA-activated protein kinase (PKR) enhanced virus replication in the primary screen, and validation experiments confirmed increased SARS-CoV protein expression and virus production upon PKR depletion. In addition, cyclin-dependent kinase 6 (CDK6) was identified as a novel antiviral host factor in SARS-CoV replication. The inventory of pro- and antiviral host factors and pathways described here substantiates and expands our understanding of SARS-CoV replication and may contribute to the identification of novel targets for antiviral therapy. ⋯ Replication of all viruses, including SARS-CoV, depends on and is influenced by cellular pathways. Although substantial progress has been made in dissecting the coronavirus replicative cycle, our understanding of the host factors that stimulate (proviral factors) or restrict (antiviral factors) infection remains far from complete. To study the role of host proteins in SARS-CoV infection, we set out to systematically identify kinase-regulated processes that influence virus replication. Protein kinases are key regulators in signal transduction, controlling a wide variety of cellular processes, and many of them are targets of approved drugs and other compounds. Our screen identified a variety of hits and will form the basis for more detailed follow-up studies that should contribute to a better understanding of SARS-CoV replication and coronavirus-host interactions in general. The identified factors could be interesting targets for the development of host-directed antiviral therapy to treat infections with SARS-CoV or other pathogenic coronaviruses.
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Coronaviruses (CoV) are enveloped, spherical, single-stranded positive-sense RNA viruses causing mainly respiratory and intestinal infections in animals and humans. Until recently five types of human coronaviruses (HCoV-OC43, HCoV-HKU1, HCoV-NL63, HCoV-229E, SARS-CoV) have been known, however a novel CoV has been identified in 2012 in Saudi Arabia. This virus, namely MERS-CoV (Middle East Respiratory Syndrome Coronavirus), was classified within Coronaviridae family, Coronavirinae sub-family, Betacoronavirus genus, clade C. ⋯ The previous studies indicated that, the viral genomes detected in the earliest cases of humans (clade A) are genetically distinct from the others (clade B) which were isolated from dromedary camels and humans. In our study, according to phylogenetic analysis of partial N gene segment, isolate ANK/1079/2014 has taken place within clade A. In conclusion, MERS-CoV appears to have limited circulation in Arabian Peninsula and Middle-Eastern countries, it should be considered in mind that travel-related cases may export the virus outside these regions leading autochtonous infections in the other parts of the world.
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Emerging Infect. Dis. · Jul 2015
Lack of Transmission among Close Contacts of Patient with Case of Middle East Respiratory Syndrome Imported into the United States, 2014.
In May 2014, a traveler from the Kingdom of Saudi Arabia was the first person identified with Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States. To evaluate transmission risk, we determined the type, duration, and frequency of patient contact among health care personnel (HCP), household, and community contacts by using standard questionnaires and, for HCP, global positioning system (GPS) tracer tag logs. Respiratory and serum samples from all contacts were tested for MERS-CoV. ⋯ All laboratory test results were negative for MERS-CoV. This contact investigation found no secondary cases, despite case-patient contact by 61 persons, and provides useful information about MERS-CoV transmission risk. Compared with GPS tracer tag recordings, self-reported contact may not be as accurate.
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Travel Med Infect Dis · Jul 2015
Middle East respiratory syndrome coronavirus (MERS-CoV): A cluster analysis with implications for global management of suspected cases.
Since the initial description of the Middle East respiratory syndrome (MERS) in September 2012, a total of 1038 cases of MERS-CoV including 460 deaths have been reported from Saudi Arabia. From August 24, 2013 to September 3, 2013, a total of 397 patients and contacts were tested for MERS-CoV. Of those tested, there were 18 (4.5%) MERS-CoV cases reported in Al-Madinah al-Munawwarah with one large cluster. ⋯ All except 4 cases were symptomatic and the case fatality rate was 39% (7 of 18). The outbreak resulted in human to human transmission of an estimated 6 cases. Contact screening showed positive test in 1 of 56 (1.8%) household contacts, and 3 of 250 (1.2%) HCWs.