SARS-CoV-2 infection of human lung epithelial cells induces TMPRSS-mediated acute fibrin deposition

Twenty microliter aliquots of BALF samples were dissolved in SDS-sample buffer and applied onto a 4-12% Nupage gel with MOPs running buffer. The run stopped after the samples migrated approximately ¼ distance into the gel. Each lane of the gel was sliced into smaller pieces, and subjected to destaining, reducing/alkylation, and in-gel trypsin digestion. The extracted peptides were applied for LC-MS/MS analysis using either a Thermo Orbitrap Fusion or a Thermo Orbitrap Fusion Lumos operated with an in-line Thermo nLC 1200 and an EASY-Spray ion source. Pepetides were separated using a 2 cm Pepmap 100 C18 trap column and a 25 cm Easy-spray Pepmap 100 C18 analytical column. MS/MS data acquisitions were operated at a 120,000 resolution (m/z 200) with a scan range of 350-1950 m/z and CID fragmentation.