In vitro screening identifies TRPV4 as target for endothelial barrier stabilization in COVID‐19

Michalick, Laura; Weidenfeld, Sarah; Grimmer, Benjamin; Fatykhova, Diana; Solymosi, Philip; Behrens, Felix; Dohmen, Melanie; Brack, Markus; Schulz, Sabrina; Thomasch, Elisa; Simmons, Szandor; Müller‐Redetzky, Holger; Suttorp, Norbert; Kurth, Florian; Corman, Victor; Hocke, Andreas; Witzenrath, Martin; Hippenstiel, Stefan; Kuebler, Wolfgang

STUDY OBJECTIVE: Endothelial dysfunction and increased microvascular permeability are hallmarks of severe COVID‐19. At present, the extent of endothelial barrier failure and its underlying mechanisms in COVID‑19 remain unclear. We hypothesized that endothelial leak results from bioactive mediators released in COVID‐19 rather than direct endothelial infection and can thus be recapitulated ex vivo by treating endothelial cells with patient plasma, thus providing a personalized screening platform for barrier‐protective interventions in COVID‐19. METHODS: Citrate plasma was sampled as part of the Pa‐COVID‐19 cohort study (ethics approval EA2/066/20) in patients with moderate (hospitalized, no invasive ventilation; WHO severity score: 3‐4) and severe (high flow O(2) or intubated and mechanically ventilated; WHO severity score: 5‐7) COVID‑19. Plasma samples were diluted to 10% (v/v) in cell culture medium without FCS and tested for their ability to disrupt barrier integrity of primary human pulmonary microvascular endothelial cells (HPMEC) monolayers by electrical cell‐substrate impedance sensing (ECIS), immunofluorescence for endothelial VE‐cadherin and F‐actin, and real‐time Ca(2+) imaging. Plasma from healthy donors served as control. RESULTS: COVID‐19 plasma was virus‐free but caused endothelial barrier disruption as measured by ECIS and gap formation in HPMEC monolayers. The extent of barrier disruption increased with disease severity but varied considerably between endothelial cells from different microvascular beds (lung/heart >> skin). The TRPV4‐antagonist HC‐067047 prevented the endothelial Ca(2+) response to COVID‐19 plasma and protected endothelial barrier integrity in lung microvascular cells. CONCLUSION: Here, we identify TRPV4 as critical regulator of microvascular permeability in COVID‑19. Targeting TRPV4‐mediated endothelial barrier failure may present a promising adjunctive therapy in COVID‐19.