title: The sclerostin-neutralizing antibody AbD09097 recognizes an epitope adjacent to sclerostin's binding site for the Wnt co-receptor LRP6.
abstract: The glycoprotein sclerostin has been identified as a negative regulator of bone growth. It exerts its function by interacting with the Wnt co-receptor LRP5/6, blocks the binding of Wnt factors and thereby inhibits Wnt signalling. Neutralizing anti-sclerostin antibodies are able to restore Wnt activity and enhance bone growth thereby presenting a new osteoanabolic therapy approach for diseases such as osteoporosis. We have generated various Fab antibodies against human and murine sclerostin using a phage display set-up. Biochemical analyses have identified one Fab developed against murine sclerostin, AbD09097 that efficiently neutralizes sclerostin's Wnt inhibitory activity. In vitro interaction analysis using sclerostin variants revealed that this neutralizing Fab binds to sclerostin's flexible second loop, which has been shown to harbour the LRP5/6 binding motif. Affinity maturation was then applied to AbD09097, providing a set of improved neutralizing Fab antibodies which particularly bind human sclerostin with enhanced affinity. Determining the crystal structure of AbD09097 provides first insights into how this antibody might recognize and neutralize sclerostin. Together with the structure-function relationship derived from affinity maturation these new data will foster the rational design of new and highly efficient anti-sclerostin antibodies for the therapy of bone loss diseases such as osteoporosis.
authors: Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors: V
authors: V
authors: Boschert
authors: Bio-Rad AbD Serotec, Zeppelinstr. 4, 82178 Puchheim, Germany.
authors: C
authors: C
authors: Frisch
authors: Pepscan Therapeutics, Zuidersluisweg 2, 8203RC, Lelystad, The Netherlands.
authors: J W
authors: JW
authors: Back
authors: Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors: K
authors: K
authors: van Pee
authors: Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors: S E
authors: SE
authors: Weidauer
authors: Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors: E-M
authors: EM
authors: Muth
authors: Leibniz Institute for Molecular Pharmacology, Robert-Roessle Str. 10, 13125 Berlin, Germany.
authors: P
authors: P
authors: Schmieder
authors: Leibniz Institute for Molecular Pharmacology, Robert-Roessle Str. 10, 13125 Berlin, Germany.
authors: M
authors: M
authors: Beerbaum
authors: Bio-Rad AbD Serotec, Zeppelinstr. 4, 82178 Puchheim, Germany.
authors: A
authors: A
authors: Knappik
authors: Pepscan Therapeutics, Zuidersluisweg 2, 8203RC, Lelystad, The Netherlands.
authors: P
authors: P
authors: Timmerman
authors: Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany mueller@biozentrum.uni-wuerzburg.de.
authors: T D
authors: 0000-0003-1862-7357
authors: TD
authors: Mueller
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D000939:Epitopes / Q000378:metabolism*; D014644:Genetic Variation; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000494:pharmacology; D060488:Low Density Lipoprotein Receptor-Related Protein-6 / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D019151:Peptide Library; D011485:Protein Binding; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D060449:Wnt Signaling Pathway
chemical_list: D057134:Antibodies, Neutralizing; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; C555475:LRP6 protein, human; D060488:Low Density Lipoprotein Receptor-Related Protein-6; C555476:Lrp6 protein, mouse; D019151:Peptide Library; D011506:Proteins; C013247:sclerotin
keywords: Wnt signalling; neutralizing antibody; osteoporosis; phage display; sclerostin