Role of PHOSPHO1 in Periodontal Development and Function

Area of Science:

• Biochemistry
• Mineralization Biology
• Periodontal Science

Background:

• Tooth root and periodontal apparatus are vital for tooth function.
• Mineralization of cementum and bone involves enzymes and matrix proteins.
• Orphan Phosphatase 1 (PHOSPHO1) is known to initiate hydroxyapatite deposition in skeletal and dentin mineralization.

Purpose of the Study:

• To investigate the functional importance of PHOSPHO1 in periodontal tissue formation and mineralization.
• To determine if PHOSPHO1 regulates the mineralization of the periodontal apparatus.

Main Methods:

• Spatiotemporal expression mapping of PHOSPHO1 during periodontal development.
• Analysis of Phospho1(-/-) mice using histology, immunohistochemistry, in situ hybridization, radiography, and micro-computed tomography.

Main Results:

• PHOSPHO1 is expressed by osteoblasts and cementoblasts during cellular cementum formation.
• Phospho1(-/-) mice showed increased cellular cementum deposition with delayed mineralization and cementoid.
• Alveolar bone in Phospho1(-/-) mice exhibited mineralization disturbances, including unmineralized osteoid and altered osteopontin deposition.
• Acellular cementum formation and periodontal ligament (PDL) structure were unaffected.

Conclusions:

• PHOSPHO1 plays a role in the mineralization of alveolar bone and cellular cementum.
• Acellular cementum formation does not appear to be substantially regulated by PHOSPHO1.
• Despite bone mineralization defects, periodontal attachment and function remain undisturbed in the absence of PHOSPHO1.