title: Reactive Center Loop (RCL) Peptides Derived from Serpins Display Independent Coagulation and Immune Modulating Activities.
abstract: Serpins regulate coagulation and inflammation, binding serine proteases in suicide-inhibitory complexes. Target proteases cleave the serpin reactive center loop scissile P1-P1' bond, resulting in serpin-protease suicide-inhibitory complexes. This inhibition requires a near full-length serpin sequence. Myxomavirus Serp-1 inhibits thrombolytic and thrombotic proteases, whereas mammalian neuroserpin (NSP) inhibits only thrombolytic proteases. Both serpins markedly reduce arterial inflammation and plaque in rodent models after single dose infusion. In contrast, Serp-1 but not NSP improves survival in a lethal murine gammaherpesvirus68 (MHV68) infection in interferon γ-receptor-deficient mice (IFNγR(-/-)). Serp-1 has also been successfully tested in a Phase 2a clinical trial. We postulated that proteolytic cleavage of the reactive center loop produces active peptide derivatives with expanded function. Eight peptides encompassing predicted protease cleavage sites for Serp-1 and NSP were synthesized and tested for inhibitory function in vitro and in vivo. In engrafted aorta, selected peptides containing Arg or Arg-Asn, not Arg-Met, with a 0 or +1 charge, significantly reduced plaque. Conversely, S-6 a hydrophobic peptide of NSP, lacking Arg or Arg-Asn with -4 charge, induced early thrombosis and mortality. S-1 and S-6 also significantly reduced CD11b(+) monocyte counts in mouse splenocytes. S-1 peptide had increased efficacy in plasminogen activator inhibitor-1 serpin-deficient transplants. Plaque reduction correlated with mononuclear cell activation. In a separate study, Serp-1 peptide S-7 improved survival in the MHV68 vasculitis model, whereas an inverse S-7 peptide was inactive. Reactive center peptides derived from Serp-1 and NSP with suitable charge and hydrophobicity have the potential to extend immunomodulatory functions of serpins.
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and.
authors.forename: Sriram
authors.initials: S
authors.lastname: Ambadapadi
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and the Interdisciplinary Institute of the Indian System of Medicine, SRM University, Kattankulathur, Tamil Nadu 603203, India.
authors.forename: Ganesh
authors.initials: G
authors.lastname: Munuswamy-Ramanujam
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and.
authors.forename: Donghang
authors.initials: D
authors.lastname: Zheng
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and.
authors.forename: Colin
authors.initials: C
authors.lastname: Sullivan
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and.
authors.forename: Erbin
authors.initials: E
authors.lastname: Dai
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and.
authors.forename: Sufi
authors.initials: S
authors.lastname: Morshed
authors.affiliation: the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and.
authors.forename: Baron
authors.initials: B
authors.lastname: McFadden
authors.affiliation: the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and.
authors.forename: Emily
authors.initials: E
authors.lastname: Feldman
authors.affiliation: the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and.
authors.forename: Melissa
authors.initials: M
authors.lastname: Pinard
authors.affiliation: the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and.
authors.forename: Robert
authors.initials: R
authors.lastname: McKenna
authors.affiliation: the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and.
authors.forename: Scott
authors.initials: S
authors.lastname: Tibbetts
authors.affiliation: From the Division of Cardiovascular Medicine, Department of Medicine, and the Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida 32608 and Alexandra.lucas@medicine.ufl.edu.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Lucas
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects* / Q000276:immunology; D004195:Disease Models, Animal; D006566:Herpesviridae Infections / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007155:Immunologic Factors / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D018144:Rhadinovirus / Q000276:immunology*; D014657:Vasculitis / Q000188:drug therapy / Q000276:immunology*
chemical_list: D007155:Immunologic Factors; D008565:Membrane Proteins; D010455:Peptides; C511174:Serp1 protein, mouse
keywords: artery; herpesvirus; inflammation; monocyte; peptides; pox viruses; reactive center loop; serpin