Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis
Background: Sclerosteosis, a severe autosomal recessive sclerosing skeletal dysplasia characterised by excessive bone formation, is caused by absence of sclerostin, a negative regulator of bone formation that binds LRP5/6 Wnt co-receptors. Current treatment is limited to surgical management of sympt...
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| Format: | Article |
| Language: | English |
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Elsevier
2021-07-01
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| Series: | Journal of Orthopaedic Translation |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214031X21000413 |
| _version_ | 1818722654236966912 |
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| author | Timothy Dreyer Mittal Shah Carl Doyle Kevin Greenslade Mark Penney Paul Creeke Apoorva Kotian Hua Zhu Ke Vinny Naidoo Gill Holdsworth |
| author_facet | Timothy Dreyer Mittal Shah Carl Doyle Kevin Greenslade Mark Penney Paul Creeke Apoorva Kotian Hua Zhu Ke Vinny Naidoo Gill Holdsworth |
| author_sort | Timothy Dreyer |
| collection | DOAJ |
| description | Background: Sclerosteosis, a severe autosomal recessive sclerosing skeletal dysplasia characterised by excessive bone formation, is caused by absence of sclerostin, a negative regulator of bone formation that binds LRP5/6 Wnt co-receptors. Current treatment is limited to surgical management of symptoms arising from bone overgrowth. This study investigated the effectiveness of sclerostin replacement therapy in a mouse model of sclerosteosis. Methods: Recombinant wild type mouse sclerostin (mScl) and novel mScl fusion proteins containing a C-terminal human Fc (mScl hFc), or C-terminal human Fc with a poly-aspartate motif (mScl hFc PD), were produced and purified using mammalian expression and standard chromatography methods. In vitro functionality and efficacy of the recombinant proteins were evaluated using three independent biophysical techniques and an in vitro bone nodule formation assay. Pharmacokinetic properties of the proteins were investigated in vivo following a single administration to young female wild type (WT) or SOST knock out (SOST-/-) mice. In a six week proof-of-concept in vivo study, young female WT or SOST-/- mice were treated with 10 mg/kg mScl hFc or mScl hFc PD (weekly), or 4.4 mg/kg mScl (daily). The effect of recombinant sclerostin on femoral cortical and trabecular bone parameters were assessed by micro computed tomography (μCT). Results: Recombinant mScl proteins bound to the extracellular domain of the Wnt co-receptor LRP6 with high affinity (nM range) and completely inhibited matrix mineralisation in vitro. Pharmacokinetic assessment following a single dose administered to WT or SOST-/- mice indicated the presence of hFc increased protein half-life from less than 5 min to at least 1.5 days. Treatment with mScl hFc PD over a six week period resulted in modest but significant reductions in trabecular volumetric bone mineral density (vBMD) and bone volume fraction (BV/TV), of 20% and 15%, respectively. Conclusion: Administration of recombinant mScl hFc PD partially corrected the high bone mass phenotype in SOST-/- mice, suggesting that bone-targeting of sclerostin engineered to improve half-life was able to negatively regulate bone formation in the SOST-/- mouse model of sclerosteosis. The translational potential of this article: These findings support the concept that exogenous sclerostin can reduce bone mass, however the modest efficacy suggests that sclerostin replacement may not be an optimal strategy to mitigate excessive bone formation in sclerosteosis, hence alternative approaches should be explored. |
| first_indexed | 2024-12-17T20:58:03Z |
| format | Article |
| id | doaj.art-44e57dc8a4744eafaa88a71c09f93a5a |
| institution | Directory Open Access Journal |
| issn | 2214-031X |
| language | English |
| last_indexed | 2024-12-17T20:58:03Z |
| publishDate | 2021-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Orthopaedic Translation |
| spelling | doaj.art-44e57dc8a4744eafaa88a71c09f93a5a2022-12-21T21:32:49ZengElsevierJournal of Orthopaedic Translation2214-031X2021-07-0129134142Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosisTimothy Dreyer0Mittal Shah1Carl Doyle2Kevin Greenslade3Mark Penney4Paul Creeke5Apoorva Kotian6Hua Zhu Ke7Vinny Naidoo8Gill Holdsworth9University of Pretoria, Pretoria, South Africa; UCB Pharma, Slough, UK; Corresponding author. 72 Jan K Marais Avenue Malanshof Randburg, 2194, South Africa.UCB Pharma, Slough, UKUCB Pharma, Slough, UKUCB Pharma, Slough, UKUCB Pharma, Slough, UKUCB Pharma, Slough, UKUCB Pharma, Slough, UKUCB Pharma, Slough, UKUniversity of Pretoria, Pretoria, South AfricaUCB Pharma, Slough, UKBackground: Sclerosteosis, a severe autosomal recessive sclerosing skeletal dysplasia characterised by excessive bone formation, is caused by absence of sclerostin, a negative regulator of bone formation that binds LRP5/6 Wnt co-receptors. Current treatment is limited to surgical management of symptoms arising from bone overgrowth. This study investigated the effectiveness of sclerostin replacement therapy in a mouse model of sclerosteosis. Methods: Recombinant wild type mouse sclerostin (mScl) and novel mScl fusion proteins containing a C-terminal human Fc (mScl hFc), or C-terminal human Fc with a poly-aspartate motif (mScl hFc PD), were produced and purified using mammalian expression and standard chromatography methods. In vitro functionality and efficacy of the recombinant proteins were evaluated using three independent biophysical techniques and an in vitro bone nodule formation assay. Pharmacokinetic properties of the proteins were investigated in vivo following a single administration to young female wild type (WT) or SOST knock out (SOST-/-) mice. In a six week proof-of-concept in vivo study, young female WT or SOST-/- mice were treated with 10 mg/kg mScl hFc or mScl hFc PD (weekly), or 4.4 mg/kg mScl (daily). The effect of recombinant sclerostin on femoral cortical and trabecular bone parameters were assessed by micro computed tomography (μCT). Results: Recombinant mScl proteins bound to the extracellular domain of the Wnt co-receptor LRP6 with high affinity (nM range) and completely inhibited matrix mineralisation in vitro. Pharmacokinetic assessment following a single dose administered to WT or SOST-/- mice indicated the presence of hFc increased protein half-life from less than 5 min to at least 1.5 days. Treatment with mScl hFc PD over a six week period resulted in modest but significant reductions in trabecular volumetric bone mineral density (vBMD) and bone volume fraction (BV/TV), of 20% and 15%, respectively. Conclusion: Administration of recombinant mScl hFc PD partially corrected the high bone mass phenotype in SOST-/- mice, suggesting that bone-targeting of sclerostin engineered to improve half-life was able to negatively regulate bone formation in the SOST-/- mouse model of sclerosteosis. The translational potential of this article: These findings support the concept that exogenous sclerostin can reduce bone mass, however the modest efficacy suggests that sclerostin replacement may not be an optimal strategy to mitigate excessive bone formation in sclerosteosis, hence alternative approaches should be explored.http://www.sciencedirect.com/science/article/pii/S2214031X21000413Bone formationSclerosteosisSclerostinSOSTTherapy |
| spellingShingle | Timothy Dreyer Mittal Shah Carl Doyle Kevin Greenslade Mark Penney Paul Creeke Apoorva Kotian Hua Zhu Ke Vinny Naidoo Gill Holdsworth Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis Journal of Orthopaedic Translation Bone formation Sclerosteosis Sclerostin SOST Therapy |
| title | Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| title_full | Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| title_fullStr | Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| title_full_unstemmed | Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| title_short | Recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| title_sort | recombinant sclerostin inhibits bone formation in vitro and in a mouse model of sclerosteosis |
| topic | Bone formation Sclerosteosis Sclerostin SOST Therapy |
| url | http://www.sciencedirect.com/science/article/pii/S2214031X21000413 |
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