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1.
Int J Mol Sci ; 23(9)2022 May 04.
Article in English | MEDLINE | ID: covidwho-1820296

ABSTRACT

Similar to many other respiratory viruses, SARS-CoV-2 targets the ciliated cells of the respiratory epithelium and compromises mucociliary clearance, thereby facilitating spread to the lungs and paving the way for secondary infections. A detailed understanding of mechanism involved in ciliary loss and subsequent regeneration is crucial to assess the possible long-term consequences of COVID-19. The aim of this study was to characterize the sequence of histological and ultrastructural changes observed in the ciliated epithelium during and after SARS-CoV-2 infection in the golden Syrian hamster model. We show that acute infection induces a severe, transient loss of cilia, which is, at least in part, caused by cilia internalization. Internalized cilia colocalize with membrane invaginations, facilitating virus entry into the cell. Infection also results in a progressive decline in cells expressing the regulator of ciliogenesis FOXJ1, which persists beyond virus clearance and the termination of inflammatory changes. Ciliary loss triggers the mobilization of p73+ and CK14+ basal cells, which ceases after regeneration of the cilia. Although ciliation is restored after two weeks despite the lack of FOXJ1, an increased frequency of cilia with ultrastructural alterations indicative of secondary ciliary dyskinesia is observed. In summary, the work provides new insights into SARS-CoV-2 pathogenesis and expands our understanding of virally induced damage to defense mechanisms in the conducting airways.


Subject(s)
COVID-19 , Animals , Cilia/metabolism , Cricetinae , Epithelium , Homeostasis , Mesocricetus , Respiratory Mucosa/metabolism , SARS-CoV-2
3.
Emerg Microbes Infect ; 10(1): 1807-1818, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1360311

ABSTRACT

Male sex was repeatedly identified as a risk factor for death and intensive care admission. However, it is yet unclear whether sex hormones are associated with disease severity in COVID-19 patients. In this study, we analysed sex hormone levels (estradiol and testosterone) of male and female COVID-19 patients (n = 50) admitted to an intensive care unit (ICU) in comparison to control non-COVID-19 patients at the ICU (n = 42), non-COVID-19 patients with the most prevalent comorbidity (coronary heart diseases) present within the COVID-19 cohort (n = 39) and healthy individuals (n = 50). We detected significantly elevated estradiol levels in critically ill male COVID-19 patients compared to all control cohorts. Testosterone levels were significantly reduced in critically ill male COVID-19 patients compared to control cohorts. No statistically significant differences in sex hormone levels were detected in critically ill female COVID-19 patients, albeit similar trends towards elevated estradiol levels were observed. Linear regression analysis revealed that among a broad range of cytokines and chemokines analysed, IFN-γ levels are positively associated with estradiol levels in male and female COVID-19 patients. Furthermore, male COVID-19 patients with elevated estradiol levels were more likely to receive ECMO treatment. Thus, we herein identified that disturbance of sex hormone metabolism might present a hallmark in critically ill male COVID-19 patients.


Subject(s)
COVID-19/mortality , COVID-19/pathology , Estradiol/blood , Testosterone/blood , Aged , Aged, 80 and over , COVID-19/blood , Critical Care , Critical Illness , Extracorporeal Membrane Oxygenation , Female , Humans , Hypogonadism/pathology , Intensive Care Units , Interferon-gamma/blood , Male , Middle Aged , Retrospective Studies , Risk Factors , SARS-CoV-2 , Severity of Illness Index , Sex Distribution
4.
Front Immunol ; 12: 640842, 2021.
Article in English | MEDLINE | ID: covidwho-1207697

ABSTRACT

Neutrophil extracellular traps (NETs) have been identified as one pathogenetic trigger in severe COVID-19 cases and therefore well-described animal models to understand the influence of NETs in COVID-19 pathogenesis are needed. SARS-CoV-2 infection causes infection and interstitial pneumonia of varying severity in humans and COVID-19 models. Pulmonary as well as peripheral vascular lesions represent a severe, sometimes fatal, disease complication of unknown pathogenesis in COVID-19 patients. Furthermore, neutrophil extracellular traps (NETs), which are known to contribute to vessel inflammation or endothelial damage, have also been shown as potential driver of COVID-19 in humans. Though most studies in animal models describe the pulmonary lesions characterized by interstitial inflammation, type II pneumocyte hyperplasia, edema, fibrin formation and infiltration of macrophages and neutrophils, detailed pathological description of vascular lesions or NETs in COVID-19 animal models are lacking so far. Here we report different types of pulmonary vascular lesions in the golden Syrian hamster model of COVID-19. Vascular lesions included endothelialitis and vasculitis at 3 and 6 days post infection (dpi), and were almost nearly resolved at 14 dpi. Importantly, virus antigen was present in pulmonary lesions, but lacking in vascular alterations. In good correlation to these data, NETs were detected in the lungs of infected animals at 3 and 6 dpi. Hence, the Syrian hamster seems to represent a useful model to further investigate the role of vascular lesions and NETs in COVID-19 pathogenesis.


Subject(s)
COVID-19/pathology , Disease Models, Animal , Extracellular Traps/immunology , Lung/pathology , SARS-CoV-2/pathogenicity , Vasculitis/pathology , Animals , COVID-19/immunology , COVID-19/virology , Cricetinae , Lung/immunology , Lung/virology , Mesocricetus , Vasculitis/immunology , Viral Proteins/metabolism
5.
Viruses ; 13(4)2021 04 08.
Article in English | MEDLINE | ID: covidwho-1178429

ABSTRACT

Vascular changes represent a characteristic feature of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection leading to a breakdown of the vascular barrier and subsequent edema formation. The aim of this study was to provide a detailed characterization of the vascular alterations during SARS-CoV-2 infection and to evaluate the impaired vascular integrity. Groups of ten golden Syrian hamsters were infected intranasally with SARS-CoV-2 or phosphate-buffered saline (mock infection). Necropsies were performed at 1, 3, 6, and 14 days post-infection (dpi). Lung samples were investigated using hematoxylin and eosin, alcian blue, immunohistochemistry targeting aquaporin 1, CD3, CD204, CD31, laminin, myeloperoxidase, SARS-CoV-2 nucleoprotein, and transmission electron microscopy. SARS-CoV-2 infected animals showed endothelial hypertrophy, endothelialitis, and vasculitis. Inflammation mainly consisted of macrophages and lower numbers of T-lymphocytes and neutrophils/heterophils infiltrating the vascular walls as well as the perivascular region at 3 and 6 dpi. Affected vessels showed edema formation in association with loss of aquaporin 1 on endothelial cells. In addition, an ultrastructural investigation revealed disruption of the endothelium. Summarized, the presented findings indicate that loss of aquaporin 1 entails the loss of intercellular junctions resulting in paracellular leakage of edema as a key pathogenic mechanism in SARS-CoV-2 triggered pulmonary lesions.


Subject(s)
Aquaporin 1/metabolism , COVID-19/pathology , Endothelial Cells/metabolism , Endothelial Cells/ultrastructure , Inflammation/pathology , Animals , Blood Vessels/ultrastructure , Disease Models, Animal , Immunohistochemistry , Lung/blood supply , Lung/ultrastructure , Lung/virology , Mesocricetus , SARS-CoV-2 , Vasculitis/pathology , Vasculitis/virology
6.
Cell Rep ; 31(3): 107549, 2020 04 21.
Article in English | MEDLINE | ID: covidwho-100496

ABSTRACT

Importin-α adaptor proteins orchestrate dynamic nuclear transport processes involved in cellular homeostasis. Here, we show that importin-α3, one of the main NF-κB transporters, is the most abundantly expressed classical nuclear transport factor in the mammalian respiratory tract. Importin-α3 promoter activity is regulated by TNF-α-induced NF-κB in a concentration-dependent manner. High-level TNF-α-inducing highly pathogenic avian influenza A viruses (HPAIVs) isolated from fatal human cases harboring human-type polymerase signatures (PB2 627K, 701N) significantly downregulate importin-α3 mRNA expression in primary lung cells. Importin-α3 depletion is restored upon back-mutating the HPAIV polymerase into an avian-type signature (PB2 627E, 701D) that can no longer induce high TNF-α levels. Importin-α3-deficient mice show reduced NF-κB-activated antiviral gene expression and increased influenza lethality. Thus, importin-α3 plays a key role in antiviral immunity against influenza. Lifting the bottleneck in importin-α3 availability in the lung might provide a new strategy to combat respiratory virus infections.


Subject(s)
Influenza A virus/immunology , Influenza, Human/immunology , Orthomyxoviridae Infections/immunology , alpha Karyopherins/biosynthesis , A549 Cells , Animals , Cell Line, Tumor , Chlorocebus aethiops , Down-Regulation , Female , HEK293 Cells , Humans , Influenza, Human/genetics , Influenza, Human/virology , Mice , Mice, Inbred C57BL , Mice, Knockout , Middle Aged , Orthomyxoviridae Infections/genetics , Orthomyxoviridae Infections/virology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Vero Cells , alpha Karyopherins/genetics , alpha Karyopherins/immunology
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