1
|
Pilchová V, Gerhauser I, Armando F, Wirz K, Schreiner T, de Buhr N, Gabriel G, Wernike K, Hoffmann D, Beer M, Baumgärtner W, von Köckritz-Blickwede M, Schulz C. Characterization of young and aged ferrets as animal models for SARS-CoV-2 infection with focus on neutrophil extracellular traps. Front Immunol 2023; 14:1283595. [PMID: 38169647 PMCID: PMC10758425 DOI: 10.3389/fimmu.2023.1283595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 11/28/2023] [Indexed: 01/05/2024] Open
Abstract
Neutrophil extracellular traps (NETs) are net-like structures released by activated neutrophils upon infection [e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] as part of the innate immune response that have protective effects by pathogen entrapment and immobilization or result in detrimental consequences for the host due to the massive release of NETs and their impaired degradation by nucleases like DNase-1. Higher amounts of NETs are associated with coronavirus disease 2019 (COVID-19) severity and are a risk factor for severe disease outcome. The objective of our study was to investigate NET formation in young versus aged ferrets to evaluate their value as translational model for SARS-CoV-2-infection and to correlate different NET markers and virological parameters. In each of the two groups (young and aged), nine female ferrets were intratracheally infected with 1 mL of 106 TCID50/mL SARS-CoV-2 (BavPat1/2020) and euthanized at 4, 7, or 21 days post-infection. Three animals per group served as negative controls. Significantly more infectious virus and viral RNA was found in the upper respiratory tract of aged ferrets. Interestingly, cell-free DNA and DNase-1 activity was generally higher in bronchoalveolar lavage fluid (BALF) but significantly lower in serum of aged compared to young ferrets. In accordance with these data, immunofluorescence microscopy revealed significantly more NETs in lungs of aged compared to young infected ferrets. The association of SARS-CoV-2-antigen in the respiratory mucosa and NET markers in the nasal conchae, but the absence of virus antigen in the lungs, confirms the nasal epithelium as the major location for virus replication as described for young ferrets. Furthermore, a strong positive correlation was found between virus shedding and cell-free DNA or the level of DNAse-1 activity in aged ferrets. Despite the increased NET formation in infected lungs of aged ferrets, the animals did not show a strong NET phenotype and correlation among tested NET markers. Therefore, ferrets are of limited use to study SARS-CoV-2 pathogenesis associated with NET formation. Nevertheless, the mild to moderate clinical signs, virus shedding pattern, and the lung pathology of aged ferrets confirm those animals as a relevant model to study age-dependent COVID-19 pathogenesis.
Collapse
Affiliation(s)
- Veronika Pilchová
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Institute of Biochemistry, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Ingo Gerhauser
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Center for Systems Neuroscience Hannover (ZSN), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Federico Armando
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Katrin Wirz
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Institute of Biochemistry, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Tom Schreiner
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Center for Systems Neuroscience Hannover (ZSN), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Nicole de Buhr
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Institute of Biochemistry, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Gülşah Gabriel
- Department for Viral Zoonoses-One Health, Leibniz Institute of Virology, Hamburg, Germany
- Institute for Virology, University for Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich Loeffler Institute, Greifswald, Germany
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich Loeffler Institute, Greifswald, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich Loeffler Institute, Greifswald, Germany
| | - Wolfgang Baumgärtner
- Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Center for Systems Neuroscience Hannover (ZSN), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Maren von Köckritz-Blickwede
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
- Institute of Biochemistry, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Claudia Schulz
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| |
Collapse
|