Heparan sulphate which binds BMP2
The invention relates to heparan sulphate GAGs obtained by affinity chromatography using the heparin-binding domain of BMP2. The GAGs were obtained from osteoblast extracellular matrix and from a commercially available heparan sulfate (Celsus HS).
1. A composition comprising a solid or solidified scaffold coated or impregnated with a therapeutically effective amount of an isolated or substantially purified heparan sulphate composition comprising a heparan sulphate component, wherein the heparan sulphate component is at least 97% HS/BMP2 which is capable of specific binding to SEQ ID NO:1 or 6, and to BMP2, wherein the heparan sulphate composition is obtained by a method comprising:
(i) providing a solid support having polypeptide molecules adhered to the support, wherein the polypeptide consists of the amino acid sequence QAKHKQRKRLKSSCKRHP [SEQ ID NO:1]or QAKHKQRKRLKSSCKRH [SEQ ID NO:6];
(ii) contacting the polypeptide molecules with a heparan sulphate fraction obtained from mammalian tissue or extracellular matrix such that polypeptide-heparan sulphate complexes are allowed to form;
(iii) partitioning polypeptide-heparan sulphate complexes from the remainder of the mixture;
(iv) dissociating the heparan sulphate from the polypeptide-heparan sulphate complexes by disrupting the polypeptide-heparan sulphate complexes; and
(v) collecting the dissociated heparan sulphate,
wherein the composition is capable of improving bone fracture repair in a mammal compared to a corresponding untreated fracture.
2. The composition of claim 1 wherein the scaffold is further coated or impregnated with BMP2 protein, mesenchymal stem cells, or a combination thereof.
3. The composition of claim 1 , wherein the scaffold is a gel.
4. The composition of claim 1 , wherein the scaffold is a hydrogel.
5. The composition of claim 1 , wherein the scaffold comprises ceramic.
6. The composition of claim 1 , wherein the scaffold comprises β-tricalcium phosphate (TCP).
7. The composition of claim 1 , wherein the scaffold comprises hydroxyapatite (HA).
8. The composition of claim 1 , wherein the scaffold comprises hyaluronic acid.
9. The composition of claim 1 , wherein the scaffold comprises demineralized bone matrix.
10. The composition of claim 1 , wherein the scaffold comprises calcium sulfate.
11. The composition of claim 1 , wherein the scaffold comprises collagen.
12. The composition of claim 1 , wherein the scaffold comprises fibrin.
13. The composition of claim 1 , wherein the scaffold is an allograft.
14. The composition of claim 1 , wherein the scaffold is an autograft.
15. The composition of claim 4 , wherein the hydrogel comprises carboxymethyl cellulose.
16. The composition according to claim 1 which binds to SEQ ID NO:1 with a K D of less than 1 μM.
17. The composition according to claim 1 wherein the HS/BMP2 is N-sulphated.
18. The composition according to claim 1 wherein the HS/BMP2 is 6-O-sulphated.
19. The composition according to claim 1 additionally comprising BMP2 protein.