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Methods Mol Biol ; 2099: 161-171, 2020.
Article in English | MEDLINE | ID: covidwho-1292551


First identified in 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel virus that can cause acute respiratory distress syndrome (ARDS), multiorgan failure, and death, with a case fatality rate of ~35%. An animal model that supports MERS-CoV infection and causes severe lung disease is useful to study pathogenesis and evaluate therapies and vaccines. The murine dipeptidyl peptidase 4 (Dpp4) protein is not a functional receptor for MERS-CoV; thus, mice are resistant to MERS-CoV infection. We generated human DPP4 knock-in (hDPP4 KI) mice by replacing exons 10-12 at the mouse Dpp4 locus with exons 10-12 from the human DPP4 gene. The resultant human DPP4 KI mice are permissive to MERS-CoV (HCoV-EMC/2012 strain) infection but develop no disease. To generate a mouse model with associated morbidity and mortality from respiratory disease, we serially passaged HCoV-EMC/2012 strain in the lungs of young hDPP4 KI mice. After 30 in vivo passages, an adapted virus clone was isolated and designated MERSMA6.1.2. This virus clone produced significantly higher titers than the parental clone in the lungs of hDPP4 KI mice and caused diffuse lung injury and a fatal respiratory infection. In this chapter, we will describe in detail the procedures used to mouse adapt MERS-CoV by serial passage of the virus in lungs. We also describe the methods used to isolate virus clones and characterize virus infection.

Coronavirus Infections/virology , Dipeptidyl Peptidase 4/genetics , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Respiratory Distress Syndrome/virology , Animals , Disease Models, Animal , Humans , Lung/virology , Mice , Mice, Inbred C57BL , Serial Passage , Virulence
Crit Care Explor ; 2(11): e0280, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-939583


Dysregulated neutrophil and platelet interactions mediate immunothrombosis and cause lung injury in coronavirus disease 2019. IV immunoglobulin modulates neutrophil activation through FcγRIII binding. We hypothesized that early therapy with IV immunoglobulin would abrogate immunothrombosis and improve oxygenation and reduce progression to mechanical ventilation in coronavirus disease 2019 pneumonia. DESIGN: Prospective randomized open label. SETTING: Inpatient hospital. PATIENTS AND INTERVENTION: Hypoxic subjects with coronavirus disease 2019 pneumonia were randomized 1:1 to receive standard of care plus IV immunoglobulin 0.5 g/kg/d with methylprednisolone 40 mg 30 minutes before infusion for 3 days versus standard of care alone. MAIN RESULTS: Sixteen subjects received IV immunoglobulin and 17 standard of care. Median ages were 51 and 58 years for standard of care and IV immunoglobulin, respectively. Acute Physiology and Chronic Health Evaluation II and Charlson comorbidity scores were similar for IV immunoglobulin and standard of care. Seven standard of care versus two IV immunoglobulin subjects required mechanical ventilation (p = 0.12, Fisher exact test). Among subjects with A-a gradient of greater than 200 mm Hg at enrollment, the IV immunoglobulin group showed: 1) a lower rate of progression to requiring mechanical ventilation (2/14 vs 7/12, p = 0.038 Fisher exact test), 2) shorter median hospital length of stay (11 vs 19 d, p = 0.01 Mann Whitney U test), 3) shorter median ICU stay (2.5 vs 12.5 d, p = 0.006 Mann Whitey U test), and 4) greater improvement in Pao2/Fio2 at 7 days (median [range] change from time of enrollment +131 [+35 to +330] vs +44·5 [-115 to +157], p = 0.01, Mann Whitney U test) than standard of care. Pao2/Fio2 improvement at day 7 was significantly less for the standard of care patients who received glucocorticoid therapy than those in the IV immunoglobulin arm (p = 0.0057, Mann Whiney U test). CONCLUSIONS: This pilot study showed that IV immunoglobulin significantly improved hypoxia and reduced hospital length of stay and progression to mechanical ventilation in coronavirus disease 2019 patients with A-a gradient greater than 200 mm Hg. A phase 3 multicenter randomized double-blinded clinical trial is under way to validate these findings.

Eur Respir J ; 56(5)2020 Nov.
Article in English | MEDLINE | ID: covidwho-648811


While severe coronavirus infections, including Middle East respiratory syndrome coronavirus (MERS-CoV), cause lung injury with high mortality rates, protective treatment strategies are not approved for clinical use.We elucidated the molecular mechanisms by which the cyclophilin inhibitors cyclosporin A (CsA) and alisporivir (ALV) restrict MERS-CoV to validate their suitability as readily available therapy in MERS-CoV infection.Calu-3 cells and primary human alveolar epithelial cells (hAECs) were infected with MERS-CoV and treated with CsA or ALV or inhibitors targeting cyclophilin inhibitor-regulated molecules including calcineurin, nuclear factor of activated T-cells (NFATs) or mitogen-activated protein kinases. Novel CsA-induced pathways were identified by RNA sequencing and manipulated by gene knockdown or neutralising antibodies. Viral replication was quantified by quantitative real-time PCR and 50% tissue culture infective dose. Data were validated in a murine MERS-CoV infection model.Both CsA and ALV reduced MERS-CoV titres and viral RNA replication in Calu-3 cells and hAECs, improving epithelial integrity. While neither calcineurin nor NFAT inhibition reduced MERS-CoV propagation, blockade of c-Jun N-terminal kinase diminished infectious viral particle release but not RNA accumulation. Importantly, CsA induced interferon regulatory factor 1 (IRF1), a pronounced type III interferon (IFNλ) response and expression of antiviral genes. Downregulation of IRF1 or IFNλ increased MERS-CoV propagation in the presence of CsA. Importantly, oral application of CsA reduced MERS-CoV replication in vivo, correlating with elevated lung IFNλ levels and improved outcome.We provide evidence that cyclophilin inhibitors efficiently decrease MERS-CoV replication in vitro and in vivo via upregulation of inflammatory antiviral cell responses, in particular IFNλ. CsA might therefore represent a promising candidate for treating MERS-CoV infection.

Coronavirus Infections/prevention & control , Cyclophilins/antagonists & inhibitors , Cyclosporine/pharmacology , Interferons/metabolism , Middle East Respiratory Syndrome Coronavirus/drug effects , Alveolar Epithelial Cells/drug effects , Alveolar Epithelial Cells/metabolism , Alveolar Epithelial Cells/virology , Animals , Calcineurin Inhibitors/pharmacology , Cell Culture Techniques , Coronavirus Infections/metabolism , Disease Models, Animal , Humans , Interferon Regulatory Factor-1/drug effects , Interferon Regulatory Factor-1/metabolism , Interferons/drug effects , Mice , Middle East Respiratory Syndrome Coronavirus/physiology , Virus Replication/drug effects