title: Cathepsin Activity-Based Probes and Inhibitor for Preclinical Atherosclerosis Imaging and Macrophage Depletion.
abstract: OBJECTIVE
  Cardiovascular disease is the leading cause of death worldwide, mainly due to an increasing prevalence of atherosclerosis characterized by inflammatory plaques. Plaques with high levels of macrophage infiltration are considered "vulnerable" while those that do not have significant inflammation are considered stable; cathepsin protease activity is highly elevated in macrophages of vulnerable plaques and contributes to plaque instability. Establishing novel tools for non-invasive molecular imaging of macrophages in plaques could aid in preclinical studies and evaluation of therapeutics. Furthermore, compounds that reduce the macrophage content within plaques should ultimately impact care for this disease.
  
  
  METHODS
  We have applied quenched fluorescent cathepsin activity-based probes (ABPs) to a murine atherosclerosis model and evaluated their use for in vivo imaging using fluorescent molecular tomography (FMT), as well as ex vivo fluorescence imaging and fluorescent microscopy. Additionally, freshly dissected human carotid plaques were treated with our potent cathepsin inhibitor and macrophage apoptosis was evaluated by fluorescent microscopy.
  
  
  RESULTS
  We demonstrate that our ABPs accurately detect murine atherosclerotic plaques non-invasively, identifying cathepsin activity within plaque macrophages. In addition, our cathepsin inhibitor selectively induced cell apoptosis of 55%±10% of the macrophage within excised human atherosclerotic plaques.
  
  
  CONCLUSIONS
  Cathepsin ABPs present a rapid diagnostic tool for macrophage detection in atherosclerotic plaque. Our inhibitor confirms cathepsin-targeting as a promising approach to treat atherosclerotic plaque inflammation.
authors.affiliation: The Institute of Drug Research, The School of Pharmacy, The Faculty of Medicine, The Hebrew University, Jerusalem, 9112001, Israel.
authors.forename: Ihab
authors.initials: I
authors.lastname: Abd-Elrahman
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, 94305, United States of America.
authors.forename: Hisanori
authors.initials: H
authors.lastname: Kosuge
authors.affiliation: The Institute of Drug Research, The School of Pharmacy, The Faculty of Medicine, The Hebrew University, Jerusalem, 9112001, Israel.
authors.forename: Tommy
authors.initials: T
authors.lastname: Wises Sadan
authors.affiliation: The Institute of Drug Research, The School of Pharmacy, The Faculty of Medicine, The Hebrew University, Jerusalem, 9112001, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Ben-Nun
authors.affiliation: Department of Pathology, Hadassah Medical Center, Jerusalem, 9112001, Israel.
authors.forename: Karen
authors.initials: K
authors.lastname: Meir
authors.affiliation: Departments of Vascular Surgery, Hadassah Medical Center, Jerusalem, 9112001, Israel.
authors.forename: Chen
authors.initials: C
authors.lastname: Rubinstein
authors.affiliation: Department of Pathology and Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, 94305, United States of America.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bogyo
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, California, 94305, United States of America.
authors.forename: Michael V
authors.initials: MV
authors.lastname: McConnell
authors.affiliation: The Institute of Drug Research, The School of Pharmacy, The Faculty of Medicine, The Hebrew University, Jerusalem, 9112001, Israel.
authors.forename: Galia
authors.identifier: http://orcid.org/0000-0002-9374-2489
authors.initials: G
authors.lastname: Blum
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D050197:Atherosclerosis / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging; D002403:Cathepsins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005456:Fluorescent Dyes; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D011480:Protease Inhibitors / Q000494:pharmacology
chemical_list: D005456:Fluorescent Dyes; D011480:Protease Inhibitors; D002403:Cathepsins