Chewing-Activated TRPV4/PIEZO1-HIF-1α-Zn Axes in a Rat Periodontal Complex

Area of Science:

• Biomaterials Science
• Mechanobiology
• Periodontal Tissue Engineering

Background:

• Periodontal tissue mineralization is influenced by mechanical forces, but the underlying pathways are poorly understood.
• Mechanosensory ion channels (MS-ion), including TRPV4 and PIEZO1, are crucial for cellular responses to mechanical stimuli.
• Understanding these pathways is vital for maintaining periodontal health and function.

Purpose of the Study:

• To investigate the relationship between mechanical loading, MS-ion channel activity, and mineralization in periodontal tissues.
• To explore the role of biometal zinc and cellular homeostasis in response to mechanical cues.
• To elucidate the impact of reduced chewing loads on periodontal ligament cells and cementum formation.

Main Methods:

• In vivo study using rats fed hard or soft diets to induce varying mechanical loads.
• Ex vivo analysis of human periodontal ligament fibroblasts treated with MS-ion channel modulators (agonists/antagonists).
• Spatially correlating mechanical strain profiles with expressions of TRPV4, PIEZO1, zinc, MFN2, p16, and HIF-1α.

Main Results:

• Reduced chewing loads (soft food) altered alveolar bone and root morphology, decreasing periodontal ligament space and increasing cementum volume.
• Impaired activation of PIEZO1 (compression) and TRPV4 (tension) was observed under reduced loads, alongside decreased mitochondrial function (MFN2) and increased senescence (p16).
• Hypoxia-inducible factor-1α (HIF-1α) expression shifted, suggesting altered blood/oxygen flow, and in vitro studies showed zinc levels correlated with transporters, not MS-ion channels.

Conclusions:

• Tension-induced TRPV4 and compression-induced PIEZO1 activation are essential for periodontal cell metabolism.
• Reduced functional loads promote a hypoxic environment conducive to cementum growth.
• Controlled mechanical loading can modulate MS-ion channels, zinc levels, and HIF-1α, highlighting zinc's role in periodontal maintenance and dentoalveolar joint function.