Kisspeptin-10 binding to Gpr54 in osteoclasts prevents bone loss by activating Dusp18-mediated dephosphorylation of...

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Osteoclast over-activation with aging leads to bone loss.
• Src kinase is crucial for osteoclast function, but its regulation by G-protein-coupled receptors (GPCRs) is unclear.
• GPCRs are significant drug targets, highlighting the need to understand their role in cellular signaling.

Purpose of the Study:

• To elucidate the mechanism by which GPR54 activation regulates Src kinase activity.
• To investigate the role of Dusp18 in the GPR54-Src signaling pathway.
• To evaluate the therapeutic potential of the Kisspeptin-10/GPR54 axis in preventing age-related bone loss.

Main Methods:

• Investigated the interaction between GPR54, Src, and Dusp18 using biochemical assays.
• Utilized knockout mouse models (Kiss1, Gpr54, Dusp18) to study in vivo effects.
• Administered Kisspeptin-10 (Kp-10) in vivo to assess its impact on bone resorption and osteoclast activity.

Main Results:

• GPR54 activation by Kp-10 leads to Dusp18-mediated dephosphorylation of Src at Tyr 416.
• Gpr54 recruits active Src and Dusp18 phosphatase via its C-terminal motif.
• Kiss1, Gpr54, and Dusp18 knockout mice exhibit hyperactive osteoclasts and bone loss.
• Kp-10 administration in vivo suppressed osteoclast activity and abrogated bone loss.

Conclusions:

• Kp-10 binding to GPR54 upregulates Dusp18, which dephosphorylates and inhibits Src kinase.
• The Kp-10/GPR54 pathway, through Dusp18-mediated Src dephosphorylation, effectively suppresses osteoclast activity.
• Targeting the Kp-10/GPR54 axis represents a promising therapeutic strategy to combat bone loss by inhibiting osteoclast-mediated bone resorption.