Topical TMPRSS2 inhibition prevents SARS-CoV-2 infection in differentiated human airway cultures

Abstract

Background: There are limited effective prophylactic/early treatments for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Viral entry requires spike protein binding to the angiotensin-converting enzyme-2 receptor and cleavage by transmembrane serine protease 2 (TMPRSS2), a cell surface serine protease. Targeting of TMPRSS2 by either androgen blockade or direct inhibition is in clinical trials in early SARS-CoV-2 infection. Methods: We used differentiated primary human airway epithelial cells at the air–liquid interface to test the impact of targeting TMPRSS2 on the prevention of SARS-CoV-2 infection. Results: We first modelled the systemic delivery of compounds. Enzalutamide, an oral androgen receptor antagonist, had no impact on SARS-CoV-2 infection. By contrast, camostat mesylate, an orally available serine protease inhibitor, blocked SARS-CoV-2 entry. However, oral camostat is rapidly metabolised in the circulation, with poor airway bioavailability. We therefore modelled local airway administration by applying camostat to the apical surface of differentiated airway cultures. We demonstrated that a brief exposure to topical camostat effectively restricts SARS-CoV-2 infection. Conclusion: These experiments demonstrate a potential therapeutic role for topical camostat for pre- or post-exposure prophylaxis of SARS-CoV-2, which can now be evaluated in a clinical trial.

Quantitative proteomic analysis of SARS-CoV-2 infection of primary human airway ciliated cells and lung epithelial cells demonstrates the effectiveness of SARS-CoV-2 innate immune evasion

“…This was consistent with our preliminary experiments showing a substantial increase in infected cells at 72 h compared to 48 h, even where the initial virus dose appears to be saturating ( Figure 2B ). In the same system, we have demonstrated that the addition of camostat mesylate 24 h & 48 h after viral inoculation leads to a greatly reduced number of infected cells at 72 h 33 . This suggests that the increasing number of infected cells up to 72 h represents spread of the virus into cells that were unable to be infected by the initial inoculum (but could be infected in subsequent rounds of viral release).…”

Air exposure and cell differentiation are essential for investigation of SARS-CoV-2 entry genes in human primary airway epithelial cells in vitro

“…Based on these results, it is conceivable that primary airway epithelial cells differentiated under ALI conditions are better in-vitro modeling systems than submerged cultures for studying SARS-CoV-2 infection. Of note, while this paper was under review, a study by Guo et al (12) has been published that clearly shows (i) ACE2 and TMPRSS2 expression is significantly increased in bronchial epithelial cells differentiated under ALI conditions compared to submerged cultured cells, (ii) differentiated ALI cultures are a suitable model to investigate SARS-CoV-2 infection in the presence or absence of therapeutic drugs. Therefore, findings from both the current study and Guo's study suggest that cells differentiated under ALI conditions are physiologically relevant models for investigating SARS-CoV-2 infection.…”

“…Furthermore, age, sex, smoking status, and airway clinical complications have been reported to be associated with ACE2 expression in human airway epithelium (7)(8)(9). In addition, epithelial cells isolated from different parts of the airways, such as the nasal passages, bronchi, and small airways, also have different expression levels of ACE2 (10)(11)(12), which may further increase the complexity of modeling these differences with in-vitro systems.…”

A novel antiviral formulation containing caprylic acid inhibits SARS-CoV-2 infection of a human bronchial epithelial cell model

“…Following exposure, SARS-CoV-2 initially replicates in the human upper airway, and ciliated bronchial epithelial cells are a major target for viral replication in the early stages of infection [1]. These cells express the viral receptor, angiotensin converting enzyme-2 (ACE-2), which is concentrated on cilia [2], and the viral entry-associated protease, transmembrane serine protease 2 (TMPRSS2) [3]. Recent studies have highlighted that variants of concern (VOC), particularly omicron, have an early replicative advantage in ciliated epithelium of the upper respiratory tract [4], with omicron replicating more rapidly, compared with delta or wild-type virus, in primary human nasal epithelial cells [5], and this variant may preferentially enter cells through the endocytic pathway, using cathepsins for viral entry [6, 7].…”