title: Modulation of vitronectin receptor-mediated osteoclast adhesion by Arg-Gly-Asp peptide analogs: a structure-function analysis.
abstract: This study details the investigation of induction of retractile shape change in the osteoclast through inhibition of adhesion between osteoclasts and matrix with (1) peptide analogs bearing an Arg-Gly-Asp (RGD) sequence, (2) antibodies to the integrin alpha V beta 3 vitronectin receptor, and (3) the RGD-containing snake venom peptide echistatin. Osteoclast retraction on dentin has been demonstrated for GRGDSP peptide, in contrast to the inactivity of the analog containing the conservative RGE sequence modification. An osteoclast adhesion assay employing rat or chick bone cells and serum-coated glass coverslips as substrate was developed for routine evaluation of inhibition of adhesion. Antibodies F4 and F11 to the beta 3 chain of rat vitronectin receptor were effective at submicromolar concentrations in rat osteoclasts (IC50 0.29 and 0.05 microM, respectively), whereas MAb 23C6 to human/chick vitronectin receptor was somewhat less effective against chick osteoclasts (IC50 1.6 microM). A rank order of RGD analog activity (mean IC50, microM) in the serum-coated glass adhesion assay was derived for the linear peptides GRGDSP (201 microM), GRGDTP (180 microM), Ac-RGDS-NH2 (84 microM), Ac-RGDV-NH2 (68 microM), RGDV (43 microM), GRGDS (38 microM), and RGDS (26 microM). The two most potent short peptides were the cyclic analog SK&F 106760 Ac-S,S-cyclo-(Cys-(N alpha Me)Arg-Gly-Asp-Pen)-NH2 (IC50 7.0 microM), and the Telios peptide H-Gly-S,S-cyclo-(Pen-Gly-Arg-Gly-Asp-Ser-Pro-Cys)-Ala-OH (IC50 6.6 microM). The snake venom peptide echistatin was the most potent substance evaluated in the serum-coated glass assay (IC50 0.78 nM) employing either rat or chick osteoclasts.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Haematology, St. Bartholomew's Hospital, London, England.
authors.forename: M A
authors.initials: MA
authors.lastname: Horton
authors.forename: E L
authors.initials: EL
authors.lastname: Dorey
authors.forename: S A
authors.initials: SA
authors.lastname: Nesbitt
authors.forename: J
authors.initials: J
authors.lastname: Samanen
authors.forename: F E
authors.initials: FE
authors.lastname: Ali
authors.forename: J M
authors.initials: JM
authors.lastname: Stadel
authors.forename: A
authors.initials: A
authors.lastname: Nichols
authors.forename: R
authors.initials: R
authors.lastname: Greig
authors.forename: M H
authors.initials: MH
authors.lastname: Helfrich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001842:Bone and Bones; D002448:Cell Adhesion / Q000187:drug effects; D002642:Chick Embryo; D003804:Dentin; D005898:Glass; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology*; D010010:Osteoclasts / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D010455:Peptides; D010456:Peptides, Cyclic / Q000494:pharmacology; D051381:Rats; D016024:Receptors, Cytoadhesin / Q000276:immunology / Q000502:physiology*; D019030:Receptors, Vitronectin; D013329:Structure-Activity Relationship; D014757:Viper Venoms / Q000494:pharmacology*
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D009842:Oligopeptides; D010455:Peptides; D010456:Peptides, Cyclic; D016024:Receptors, Cytoadhesin; D019030:Receptors, Vitronectin; D014757:Viper Venoms; C057986:echistatin; C071275:SK&F 106760; C047981:arginyl-glycyl-aspartic acid