SARS-CoV-2 infection induces the dedifferentiation of multiciliated cells and impairs mucociliary clearance

Rémy Robinot ,Olivier Gorgette ,Julien Fernandes ,Céline Trébeau ,Olivier Schwartz ,Hervé Bourhy ,Marc Lecuit ,Raphaël Etournay ,Nikaïa Smith ,Sylvain Levallois ,Françoise Lazarini ,Stéphane Rigaud ,Adeline Mallet ,Gérard Duménil ,Timothée Bruel ,Vincent Michel ,Stacy Gellenoncourt ,Florence Larrous ,Pierre-Marie Lledo ,Darragh Duffy ,Guilherme Dias De Melo ,Mathieu Hubert ,Catherine Thouvenot ,Samy Gobaa ,Lisa A Chakrabarti

doi:10.1038/s41467-021-24521-x

Abstract

Understanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19. Here we examine the functional and structural consequences of SARS-CoV-2 infection in a reconstructed human bronchial epithelium model. SARS-CoV-2 replication causes a transient decrease in epithelial barrier function and disruption of tight junctions, though viral particle crossing remains limited. Rather, SARS-CoV-2 replication leads to a rapid loss of the ciliary layer, characterized at the ultrastructural level by axoneme loss and misorientation of remaining basal bodies. Downregulation of the master regulator of ciliogenesis Foxj1 occurs prior to extensive cilia loss, implicating this transcription factor in the dedifferentiation of ciliated cells. Motile cilia function is compromised by SARS-CoV-2 infection, as measured in a mucociliary clearance assay. Epithelial defense mechanisms, including basal cell mobilization and interferon-lambda induction, ramp up only after the initiation of cilia damage. Analysis of SARS-CoV-2 infection in Syrian hamsters further demonstrates the loss of motile cilia in vivo. This study identifies cilia damage as a pathogenic mechanism that could facilitate SARS-CoV-2 spread to the deeper lung parenchyma.

Highlights

Understanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19
SARS-CoV-2 is genetically closely related to the original SARSCoV-1 coronavirus, which caused an outbreak of severe acute respiratory syndrome in 2002–2003, affecting about 8000 patients and resulting in 774 reported deaths[12,13]
SARS-CoV-2 infection was studied in the MucilAirTM model, consisting of primary human bronchial epithelial cells grown over a porous membrane and differentiated at the air/liquid interface (ALI) for over 4 weeks (Fig. 1A)

Summary

Introduction

Understanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19. SARS-CoV-2 is genetically closely related to the original SARSCoV-1 coronavirus, which caused an outbreak of severe acute respiratory syndrome in 2002–2003, affecting about 8000 patients and resulting in 774 reported deaths[12,13]. Both viruses use the angiotensin converting enzyme 2 (ACE2) as a receptor, and the transmembrane serine protease 2 (TMPRSS2) as a viral entry cofactor[2,14]. Studies of autopsy samples from COVID-19 patients and experimental infection of tissue explants have documented SARS-CoV-2 replication predominantly in the upper and lower airway epithelia and in the lung alveoli[19,20,21]. The consequences of SARS-CoV-2 infection on ciliated cell differentiation and functions, remain to be fully characterized

Methods

Results

Conclusion