biostudies-literatureSiegel PMDeutsche ForschungsgemeinschaftDeutsche Gesellschaft für Kardiologie-Herz und Kreislaufforschung.European Research CouncilDeutsche Stiftung für HerzforschungNational Health and Medical Research CouncilLeukemia Foundation17https://www.ebi.ac.uk/biostudies/studies/S-EPMC7960600biostudies-literatureUnknown116(1)The monocyte β₂-integrin Mac-1 is crucial for leukocyte-endothelium interaction, rendering it an attractive therapeutic target for acute and chronic inflammation. Using phage display, a Designed-Ankyrin-Repeat-Protein (DARPin) was selected as a novel binding protein targeting and blocking the α_M I-domain, an activation-specific epitope of Mac-1. This DARPin, named F7, specifically binds to activated Mac-1 on mouse and human monocytes as determined by flow cytometry. Homology modelling and docking studies defined distinct interaction sites which were verified by mutagenesis. Intravital microscopy showed reduced leukocyte-endothelium adhesion in mice treated with this DARPin. Using mouse models of sepsis, myocarditis and ischaemia/reperfusion injury, we demonstrate therBasic research in cardiologyA DARPin targeting activated Mac-1 is a novel diagnostic tool and potential anti-inflammatory agent in myocarditis, sepsis and myocardial infarction.PMC79606008534251174098Anto-Michel NDiehl PHollederer LPeter KWaggershauser PHelbing TWolf DMitre LSPrzewosnik AFlierl USiegel PMMauler MWang XHolien JStankova IOrlean LTonnar XLamprecht CVedecnik CMoser MParker MWBender IBojti IBassler NEhrlich JLi TBode CfalseA DARPin targeting activated Mac-1 is a novel diagnostic tool and potential anti-inflammatory agent in myocarditis, sepsis and myocardial infarction.The monocyte β₂-integrin Mac-1 is crucial for leukocyte-endothelium interaction, rendering it an attractive therapeutic target for acute and chronic inflammation. Using phage display, a Designed-Ankyrin-Repeat-Protein (DARPin) was selected as a novel binding protein targeting and blocking the α_M I-domain, an activation-specific epitope of Mac-1. This DARPin, named F7, specifically binds to activated Mac-1 on mouse and human monocytes as determined by flow cytometry. Homology modelling and docking studies defined distinct interaction sites which were verified by mutagenesis. Intravital microscopy showed reduced leukocyte-endothelium adhesion in mice treated with this DARPin. Using mouse models of sepsis, myocarditis and ischaemia/reperfusion injury, we demonstrate ther2021-01-01T00:00:00Z2021 Mar2025-04-04T12:53:10.93Z2022-02-09T08:01:43.811ZS-EPMC79606003372110610.1007/s00395-021-00849-9