title: Identification of a DNA aptamer that inhibits sclerostin's antagonistic effect on Wnt signalling.
abstract: Sclerostin is an extracellular negative regulator of bone formation that is a recognized therapeutic target for osteoporosis therapy. In the present study, we performed DNA aptamer selection against sclerostin, then characterized aptamer-sclerostin binding and the ability to inhibit sclerostin function in cell culture. We show that a selected DNA aptamer was highly selective for binding to sclerostin with affinities in the nanomolar range as determined by solid-phase assays and by isothermal titration calorimetry. Binding between sclerostin and the aptamer was exothermic and enthalpically driven. CD confirmed that the aptamer had temperature-dependent parallel G-quadruplex characteristics. The aptamer was stabilized with 3' inverted thymidine to investigate efficacy at inhibiting sclerostin function in cell culture. The stabilized DNA aptamer showed potent and specific dose-dependent inhibition of sclerostin's antagonistic effect on Wnt activity using a reporter assay. Taken together, the present findings suggest an alternative approach to inhibiting sclerostin function with therapeutic potential.
authors.affiliation: Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Ka To
authors.initials: KT
authors.lastname: Shum
authors.forename: Celine
authors.initials: C
authors.lastname: Chan
authors.forename: Ching-Man
authors.initials: CM
authors.lastname: Leung
authors.forename: Julian A
authors.initials: JA
authors.lastname: Tanner
mesh_terms: D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000494:pharmacology*; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D002151:Calorimetry; D002942:Circular Dichroism; D005819:Genetic Markers; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D011485:Protein Binding; D015398:Signal Transduction; D013816:Thermodynamics; D051153:Wnt Proteins / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D052157:Aptamers, Nucleotide; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; C486030:Sost protein, mouse; D051153:Wnt Proteins