Mutations in the Notch pathway alter the patterning of multifidus

Area of Science:

• Developmental biology
• Genetics
• Orthopedics

Background:

• Idiopathic scoliosis may involve epaxial muscle defects, particularly the multifidus.
• The embryonic segmentation process, regulated by Notch signaling, patterns epaxial muscles and vertebrae.
• Mutations in DLL3 and LFNG are linked to spinal disorders, but their myological effects are unknown.

Purpose of the Study:

• To investigate the myological phenotypes of epaxial muscles in genetic models of scoliosis.
• To analyze the role of Notch signaling pathway modulators (DLL3, LFNG) in multifidus muscle development.

Main Methods:

• Analysis of the multifidus muscle in mouse models with mutations in delta-like 3 (Dll3) and lunatic fringe (Lfng).
• Statistical analysis to correlate myological anomalies with osteological defects.

Main Results:

• Observed significant changes in the cranio-caudal borders of the multifidus muscle in Dll3 and Lfng mutant mice.
• Found no significant association between most multifidus anomalies and vertebral defects.
• Highlighted a potential role for Notch signaling in epaxial muscle patterning independent of vertebral development.

Conclusions:

• DLL3 and LFNG mutations can cause distinct multifidus muscle defects.
• Notch signaling plays a previously unappreciated role in patterning epaxial muscle groups.
• These findings suggest an additional mechanism for DLL3 and LFNG in the etiology of idiopathic scoliosis.