Abstract
BackgroundDuring viral-induced myocarditis, immune cells migrate towards the site of infection and secrete proteases, which in turn can act as sheddases by cleaving extracellular domains of transmembrane proteins. We were interested in the shedding of the Coxsackie- and adenovirus receptor (CAR) that acts as an entry receptor for both eponymous viruses, which cause myocarditis. CAR shedding by secreted immune proteases could result in a favourable outcome of myocarditis as CAR’s extracellular domain would be removed from the cardiomyocytes’ surface leading to decreased susceptibility to ongoing viral infections.Methods and resultsIn this work, matrix metalloproteinases and serine proteinases were screened for their proteolytic activity towards human CAR. Whereas matrix metalloproteinases, proteinase 3, and cathepsin G did not cleave human recombinant CAR or only within long incubation times, neutrophil elastase showed a distinct cleavage pattern of CAR’s extracellular domain that was time- and dose-dependent. Neutrophil elastase cleaves CAR at its membrane-proximal immunoglobulin domain as we determined by nanoLC-MS/MS. Furthermore, neutrophil elastase treatment of cells reduced CAR surface levels as seen by flow cytometry and immunofluorescence microscopy.ConclusionsWith this study, we show that CAR might be a target for shedding by neutrophil elastase.
Highlights
The Coxsackie- and adenovirus receptor (CAR) is a transmembrane protein with two extracellular immunoglobulin domains
Recombinant extracellular CAR domain is cleaved by Matrix metalloproteinases (MMPs)‐3 and serine proteases
Recombinant human CAR extracellular domain with C-terminal 6xHis tag was digested by serine proteases and catalytic MMP domains overnight and cleavage products were visualised by Western blots using anti-CAR N-terminus antibody
Summary
The Coxsackie- and adenovirus receptor (CAR) is a transmembrane protein with two extracellular immunoglobulin domains. CAR plays an important role during embryogenesis as it is crucial for the development of the heart [1] and the lymphatic vasculature system [2] It was first described as entry receptor for both human pathogen viruses [3, 4]. During viral-induced myocarditis, immune cells migrate towards the site of infection and secrete proteases, which in turn can act as sheddases by cleaving extracellular domains of transmembrane proteins. CAR shedding by secreted immune proteases could result in a favourable outcome of myocarditis as CAR’s extracellular domain would be removed from the cardiomyocytes’ surface leading to decreased susceptibility to ongoing viral infections. Proteinase 3, and cathepsin G did not cleave human recombinant CAR or only within long incubation times, neutrophil elastase showed a distinct cleavage pattern of CAR’s extracellular domain that was time- and dose-dependent. Conclusions With this study, we show that CAR might be a target for shedding by neutrophil elastase
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
