title: Peptide Inhibitor of Complement C1 (PIC1) Rapidly Inhibits Complement Activation after Intravascular Injection in Rats.
abstract: The complement system has been increasingly recognized to play a pivotal role in a variety of inflammatory and autoimmune diseases. Consequently, therapeutic modulators of the classical, lectin and alternative pathways of the complement system are currently in pre-clinical and clinical development. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement and is referred to as Peptide Inhibitor of Complement C1 (PIC1). In this study, we determined that the lead PIC1 variant demonstrates a salt-dependent binding to C1q, the initiator molecule of the classical pathway. Additionally, this peptide bound to the lectin pathway initiator molecule MBL as well as the ficolins H, M and L, suggesting a common mechanism of PIC1 inhibitory activity occurs via binding to the collagen-like tails of these collectin molecules. We further analyzed the effect of arginine and glutamic acid residue substitution on the complement inhibitory activity of our lead derivative in a hemolytic assay and found that the original sequence demonstrated superior inhibitory activity. To improve upon the solubility of the lead derivative, a pegylated, water soluble variant was developed, structurally characterized and demonstrated to inhibit complement activation in mouse plasma, as well as rat, non-human primate and human serum in vitro. After intravenous injection in rats, the pegylated derivative inhibited complement activation in the blood by 90% after 30 seconds, demonstrating extremely rapid function. Additionally, no adverse toxicological effects were observed in limited testing. Together these results show that PIC1 rapidly inhibits classical complement activation in vitro and in vivo and is functional for a variety of animal species, suggesting its utility in animal models of classical complement-mediated diseases.
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Sharp
authors.affiliation: Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Hair
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Haree K
authors.initials: HK
authors.lastname: Pallera
authors.affiliation: Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Parvathi S
authors.initials: PS
authors.lastname: Kumar
authors.affiliation: Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Clifford T
authors.initials: CT
authors.lastname: Mauriello
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America; The Leroy T. Canoles Jr. Cancer Research Center, Norfolk, Virginia, United States of America.
authors.forename: Julius O
authors.initials: JO
authors.lastname: Nyalwidhe
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Cody A
authors.initials: CA
authors.lastname: Phelps
authors.affiliation: Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Dalnam
authors.initials: D
authors.lastname: Park
authors.affiliation: Univ. Grenoble Alpes, IBS, F-38044, Grenoble, France; CNRS, IBS, F-38044, Grenoble, France; CEA, IBS, F-38044, Grenoble, France.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Thielens
authors.affiliation: Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Pascal
authors.affiliation: Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia, United States of America.
authors.forename: Waldon
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Duffy
authors.affiliation: Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Lattanzio
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America; Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America; Children's Specialty Group, Norfolk, Virginia, United States of America.
authors.forename: Kenji M
authors.initials: KM
authors.lastname: Cunnion
authors.affiliation: Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia, United States of America; Department of Pediatrics, Eastern Virginia Medical School, Norfolk, Virginia, United States of America.
authors.forename: Neel K
authors.initials: NK
authors.lastname: Krishna
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003167:Complement Activation / Q000187:drug effects*; D015922:Complement C1q / Q000276:immunology*; D006801:Humans; D007267:Injections; D037102:Lectins / Q000276:immunology; D008252:Macaca fascicularis; D008297:Male; D037601:Mannose-Binding Lectin / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000008:administration & dosage / Q000097:blood / Q000737:chemistry* / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012756:Sheep; D000097604:Ficolins
chemical_list: D015922:Complement C1q; D037102:Lectins; D037601:Mannose-Binding Lectin; D010455:Peptides; D000097604:Ficolins