Sclerostin Mediation in Bone Metabolism

Sclerostin is a glycoprotein chiefly secreted by osteocytes that serves as a key antagonist of the Wnt signalling pathway, thereby modulating the balance between bone formation and resorption. By binding to Wnt co-receptors on osteoblast-lineage cells, sclerostin inhibits downstream β-catenin activation, reducing osteoblast proliferation and matrix synthesis. Concurrently, sclerostin promotes osteoclastogenesis indirectly by altering the local ratio of RANKL to osteoprotegerin, thus facilitating bone resorption. Mechanical loading down-regulates sclerostin expression, enabling adaptive bone accrual, whereas disuse and ageing elevate sclerostin levels, contributing to bone loss. Beyond its physiological role, sclerostin has emerged as a therapeutic target in osteoporosis, with antibody-mediated blockade demonstrating both anabolic and antiresorptive effects. However, global inhibition of sclerostin has been linked to off-target cardiovascular concerns, prompting efforts to dissect domain-specific functions and refine intervention strategies. Innovations in understanding sclerostin’s post-translational modifications, receptor interactions and tissue-specific activities are expanding the prospects for safer, more effective bone-targeted therapies.

Research from Nature Portfolio

Genetic truncation of sclerostin loop 3 has been shown to uncouple its cardiovascular protective effect from its inhibitory action on bone formation. A novel aptamer targeting loop 3 preserves vascular integrity while enabling significant bone accrual in preclinical models. This work paves the way for domain-selective sclerostin modulation that mitigates cardiovascular risk without sacrificing skeletal benefit.

Engineering a bispecific antibody that simultaneously neutralises sclerostin and Dickkopf-1 has demonstrated synergistic bone formation and enhanced fracture repair in rodent and non-human primate studies. By co-inhibiting two distinct Wnt antagonists, this approach amplifies osteoanabolic signalling and accelerates structural recovery, offering a promising advancement for treating low bone mass and improving fracture outcomes.

Sclerostin Mediation in Bone Metabolism publication trend

The graph below shows the total number of articles in sclerostin mediation in bone metabolism across all publications each year (not limited to Nature Index journals).

Technical terms

Sclerostin: A secreted glycoprotein from osteocytes that inhibits Wnt-mediated osteoblast activity and modulates bone resorption.

Wnt signalling pathway: A conserved cell signalling cascade that regulates osteoblast proliferation, differentiation and bone matrix production via β-catenin activation.

Osteocytes: Terminally differentiated bone cells embedded within the mineralised matrix that sense mechanical load and secrete regulatory factors.

Glycosylation: Enzymatic addition of sugar moieties to proteins, influencing their stability, localisation and function.

PDGF receptor signalling: A pathway initiated by platelet-derived growth factors binding to their receptors on osteoblast-lineage cells, affecting osteoclastogenesis through M-CSF release.

References

1. B4GALNT3 regulates glycosylation of sclerostin and bone mass. EBioMedicine (2023).
2. Sclerostin blockade inhibits bone resorption through PDGF receptor signaling in osteoblast lineage cells. JCI Insight (2024).
3. SOST/Sclerostin impairs the osteogenesis and angiogesis in glucocorticoid-associated osteonecrosis of femoral head. Molecular Medicine (2024).
4. A bispecific antibody targeting sclerostin and DKK-1 promotes bone mass accrual and fracture repair. Nature Communications (2016).
5. Sclerostin Binds to LRP5/6 and Antagonizes Canonical Wnt Signaling*. Journal of Biological Chemistry (2005).
6. Sclerostin Stimulates Osteocyte Support of Osteoclast Activity by a RANKL-Dependent Pathway. PLOS ONE (2011).
7. Sclerostin's role in bone's adaptive response to mechanical loading. Bone (2016).
8. Targeting loop3 of sclerostin preserves its cardiovascular protective action and promotes bone formation. Nature Communications (2022).