[Imaging of bone and joint destruction]

Area of Science:

• Cell Biology
• Immunology
• Biochemistry

Background:

• Osteoclasts are crucial for bone remodeling, differentiating from myeloid precursors.
• Dysfunctional osteoclasts contribute to bone diseases like arthritis.
• Understanding osteoclast dynamics in vivo is essential for therapeutic development.

Purpose of the Study:

• To develop and apply advanced imaging techniques for in vivo osteoclast research.
• To investigate the regulatory mechanisms of osteoclast precursor migration.
• To characterize functional states of differentiated osteoclasts.

Main Methods:

• Intravital two-photon microscopy for real-time visualization of osteoclasts and precursors.
• Development of pH-sensing chemical fluorescent probes for in vivo acidification detection.
• In vivo imaging of osteoclast behavior on bone surfaces.

Main Results:

• Sphingosine-1-phosphate was identified as a critical regulator of osteoclast precursor migration.
• Two distinct functional states of osteoclasts were identified: bone-resorptive and non-resorptive.
• Localized acidification by bone-resorbing osteoclasts was detected in vivo.

Conclusions:

• Advanced intravital imaging provides novel insights into osteoclast dynamics.
• Targeting osteoclast migration and function holds therapeutic potential for bone-destructive diseases.
• The developed imaging system and probes are valuable tools for studying inflammatory and bone diseases.