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Boschert V, Frisch C, Back JW, van Pee K, Weidauer SE, Muth EM, Schmieder P, Beerbaum M, Knappik A, Timmerman P, Mueller TD. The sclerostin-neutralizing antibody AbD09097 recognizes an epitope adjacent to sclerostin's binding site for the Wnt co-receptor LRP6. Open Biol 2017; 6:rsob.160120. [PMID: 27558933 PMCID: PMC5008011 DOI: 10.1098/rsob.160120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/25/2016] [Indexed: 11/12/2022] Open
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.
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Affiliation(s)
- V Boschert
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
| | - C Frisch
- Bio-Rad AbD Serotec, Zeppelinstr. 4, 82178 Puchheim, Germany
| | - J W Back
- Pepscan Therapeutics, Zuidersluisweg 2, 8203RC, Lelystad, The Netherlands
| | - K van Pee
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
| | - S E Weidauer
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
| | - E-M Muth
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
| | - P Schmieder
- Leibniz Institute for Molecular Pharmacology, Robert-Roessle Str. 10, 13125 Berlin, Germany
| | - M Beerbaum
- Leibniz Institute for Molecular Pharmacology, Robert-Roessle Str. 10, 13125 Berlin, Germany
| | - A Knappik
- Bio-Rad AbD Serotec, Zeppelinstr. 4, 82178 Puchheim, Germany
| | - P Timmerman
- Pepscan Therapeutics, Zuidersluisweg 2, 8203RC, Lelystad, The Netherlands
| | - T D Mueller
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany
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Watanabe H, Yageta S, Imamura H, Honda S. Biosensing Probe for Quality Control Monitoring of the Structural Integrity of Therapeutic Antibodies. Anal Chem 2016; 88:10095-10101. [PMID: 27700033 DOI: 10.1021/acs.analchem.6b02526] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ideal quality control of therapeutic antibodies involves analytical techniques with high-sensitivity, high-resolution, and high-throughput performance. Few technologies that assess the physicochemical heterogeneity of antibodies, however, meet all the required demands. We developed a biosensing method for the quality control of therapeutic antibodies based on an artificial protein, AF.2A1, which discriminates between the native and the non-native three-dimensional structures of immunoglobulin G (IgG). AF.2A1 specifically recognized non-native IgG spiked into a solution of native IgG, thereby making it possible to detect contamination by a small amount of non-native IgG, which is difficult using conventional size-based separation or spectroscopic techniques. Using AF.2A1 as an analytical probe, we determined the concentration of non-native IgG formed under various pH conditions. The probe was also applicable to accelerated tests of the long-term stability of a therapeutic antibody, allowing monitoring of the formation of non-native IgG at elevated temperatures and extended periods of storage. AF.2A1, a proteinous probe, can be combined with established methods or devices to achieve high-throughput assays and provides the potential for probe-based biosensing for the quality control of therapeutic antibodies.
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Affiliation(s)
- Hideki Watanabe
- Biomedical Research Institute, the National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Seiki Yageta
- Biomedical Research Institute, the National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
| | - Hiroshi Imamura
- Biomedical Research Institute, the National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Shinya Honda
- Biomedical Research Institute, the National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, the University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
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Boschert V, van Dinther M, Weidauer S, van Pee K, Muth EM, ten Dijke P, Mueller TD. Mutational analysis of sclerostin shows importance of the flexible loop and the cystine-knot for Wnt-signaling inhibition. PLoS One 2013; 8:e81710. [PMID: 24312339 PMCID: PMC3843708 DOI: 10.1371/journal.pone.0081710] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022] Open
Abstract
The cystine-knot containing protein Sclerostin is an important negative regulator of bone growth and therefore represents a promising therapeutic target. It exerts its biological task by inhibiting the Wnt (wingless and int1) signaling pathway, which participates in bone formation by promoting the differentiation of mesenchymal stem cells to osteoblasts. The core structure of Sclerostin consists of three loops with the first and third loop (Finger 1 and Finger 2) forming a structured β-sheet and the second loop being unstructured and highly flexible. Biochemical data showed that the flexible loop is important for binding of Sclerostin to Wnt co-receptors of the low-density lipoprotein related-protein family (LRP), by interacting with the Wnt co-receptors LRP5 or -6 it inhibits Wnt signaling. To further examine the structural requirements for Wnt inhibition, we performed an extensive mutational study within all three loops of the Sclerostin core domain involving single and multiple mutations as well as truncation of important regions. By this approach we could confirm the importance of the second loop and especially of amino acids Asn92 and Ile94 for binding to LRP6. Based on a Sclerostin variant found in a Turkish family suffering from Sclerosteosis we generated a Sclerostin mutant with cysteines 84 and 142 exchanged thereby removing the third disulfide bond of the cystine-knot. This mutant binds to LRP6 with reduced binding affinity and also exhibits a strongly reduced inhibitory activity against Wnt1 thereby showing that also elements outside the flexible loop are important for inhibition of Wnt by Sclerostin. Additionally, we examined the effect of the mutations on the inhibition of two different Wnt proteins, Wnt3a and Wnt1. We could detect clear differences in the inhibition of these proteins, suggesting that the mechanism by which Sclerostin antagonizes Wnt1 and Wnt3a is fundamentally different.
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Affiliation(s)
- Verena Boschert
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Wuerzburg, Germany
| | - Maarten van Dinther
- Department of Molecular Cell Biology, Cancer Genomics Center Netherlands and Center for Biomedical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Stella Weidauer
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Wuerzburg, Germany
| | - Katharina van Pee
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Wuerzburg, Germany
| | - Eva-Maria Muth
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Wuerzburg, Germany
| | - Peter ten Dijke
- Department of Molecular Cell Biology, Cancer Genomics Center Netherlands and Center for Biomedical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Thomas D. Mueller
- Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute of the University Wuerzburg, Wuerzburg, Germany
- * E-mail:
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