C-type natriuretic peptide analog treatment of craniosynostosis in a Crouzon syndrome mouse model

Area of Science:

• Skeletal biology
• Developmental biology
• Pharmacology

Background:

• Activating mutations in fibroblast growth factor receptors (FGFRs) are primary drivers of skeletal dysplasias.
• Fibroblast growth factor receptor signaling inhibition presents a therapeutic target for these conditions.
• BMN 111, a C-type natriuretic peptide analog, targets RAF1 kinase via natriuretic peptide receptor 2 (NPR2) and has shown efficacy in other skeletal dysplasia models.

Purpose of the Study:

• To investigate the therapeutic potential of BMN 111 in the Fgfr2cC342Y/+ Crouzon syndrome mouse model, focusing on craniosynostosis and skull malformations.
• To assess the effects of BMN 111 on suture patency, skull dimensions, and long bone length.

Main Methods:

• Demonstrated natriuretic peptide receptor 2 (NPR2) expression in murine coronal suture and spheno-occipital synchondrosis.
• Administered daily injections of BMN 111 or vehicle to Fgfr2cC342Y/+ and wild-type (WT) mice from postnatal days 3 to 31.
• Evaluated skeletal morphology using micro-computed tomography.

Main Results:

• BMN 111 significantly enhanced long bone growth in both WT and Fgfr2cC342Y/+ mice.
• Skull dimensions and suture patency were not significantly affected by BMN 111 treatment in the Crouzon syndrome model.
• A minor but significant increase in anterior cranial base relative length was observed.

Conclusions:

• The efficacy of BMN 111 in skeletal dysplasias may be dependent on the bone formation process (endochondral vs. intramembranous), the specific FGFR mutation, and resultant signaling pathway alterations.
• BMN 111 demonstrates differential effects across various skeletal dysplasia types, suggesting context-specific therapeutic responses.