miR181a/b-1 controls osteocyte metabolism and mechanical properties independently of bone morphology

Area of Science:

• Bone biology and biomechanics
• Molecular mechanisms of bone quality
• MicroRNA regulation in skeletal health

Background:

• Bone fracture resistance depends on both mass and quality, but molecular regulators of bone quality are not fully understood.
• MicroRNA 181a/b-1 (miR181a/b-1) is implicated in bone homeostasis and disease, yet its specific role in osteocyte function and bone quality remains unclear.

Purpose of the Study:

• To investigate the role of osteocyte-intrinsic miR181a/b-1 in regulating bone quality and mechanical properties.
• To explore the sexually dimorphic effects of miR181a/b-1 on bone structure and metabolism.

Main Methods:

• Osteocyte-specific deletion of miR181a/b-1 in vivo.
• Assessment of bone mechanical behavior and cortical bone morphology.
• Bioenergetic testing of osteocyte-like cells and transcriptomic analysis of cortical bone.

Main Results:

• Deletion of osteocyte-intrinsic miR181a/b-1 compromised bone mechanical behavior in both sexes.
• Sex-specific alterations in cortical bone morphology and mechanical parameters were observed.
• miR181a/b-1 deficiency impacted osteocyte bioenergetics and cellular metabolism.

Conclusions:

• Osteocyte-intrinsic miR181a/b-1 plays a significant role in regulating osteocyte bioenergetics.
• miR181a/b-1 exhibits sexually dimorphic control over cortical bone morphology and mechanical properties.
• Osteocyte metabolism is a key regulator of bone mechanical behavior, influenced by miR181a/b-1.