Wnts produced by Osterix-expressing osteolineage cells regulate their proliferation and differentiation

Area of Science:

• Bone Biology
• Developmental Biology
• Cell Signaling

Background:

• Wnt signaling is vital for bone development.
• The specific cells producing Wnts in bone remain unidentified.
• Understanding Wnt-producing cells is key to bone biology.

Purpose of the Study:

• Identify Wnt-producing cells in neonatal mouse bone.
• Determine the role of these cells in bone formation.
• Investigate the autocrine function of Wnt signaling in osteolineage cells.

Main Methods:

• In situ hybridization to survey Wnt gene expression.
• Lineage tracing to track osteolineage cell fate.
• Genetic experiments to inhibit Wnt secretion in vivo.

Main Results:

• Osterix-expressing cells were found to coexpress Wnt and Wnt target gene Axin2.
• Axin2-expressing osteolineage cells were shown to sustain long-term bone formation.
• Inhibition of Wnt secretion by Osterix-expressing cells led to impaired cell proliferation and differentiation.

Conclusions:

• Osterix-expressing cells are the source of Wnts in neonatal bone.
• These cells utilize autocrine Wnt signaling to regulate their proliferation and differentiation.
• This study clarifies a critical mechanism in bone development and homeostasis.