Masticatory Stress Maintains Mucosal Homeostasis via M2 Polarization

Area of Science:

• Oral Biology
• Tissue Engineering
• Immunology

Background:

• Mastication (chewing) is crucial for digestion and maintaining oral tissue homeostasis.
• The oral mucosa withstands significant mechanical stress during chewing, requiring a balance between damage and repair.
• Molecular mechanisms of rapid oral mucosal wound healing under masticatory stress are not fully understood.

Purpose of the Study:

• To investigate the impact of masticatory stress on oral mucosal wound healing.
• To elucidate the molecular mechanisms, including the role of mechanosensitive genes and immune cells, in masticatory stress-induced tissue repair.

Main Methods:

• Comparison of hard palate mucosal wound healing in mice fed soft versus hard food diets.
• RNA sequencing to analyze gene expression changes (e.g., Piezo1, Tgf-β1, Tgf-βr2).
• Immunofluorescence staining, flow cytometry, and PCR to assess macrophage polarization and gene expression.
• Genetic deletion of Piezo1 in macrophages to evaluate its role in healing.

Main Results:

• Reduced masticatory stress (soft food diet) decelerated hard palate wound healing and reduced Ki67-positive cells.
• Soft food diet group showed lower expression of Piezo1, transforming growth factor β1 (Tgf-β1), and Tgf-β receptor 2 (Tgf-βr2).
• Masticatory stress induced M2 macrophage polarization and increased Tgf-β1 secretion, promoting healing.
• Specific deletion of Piezo1 in macrophages attenuated stress-induced accelerated healing.

Conclusions:

• Masticatory stress significantly impacts oral mucosal wound healing through Piezo1-dependent mechanisms.
• Masticatory stress promotes M2 macrophage polarization and Tgf-β1 secretion, crucial for accelerated tissue repair.
• Physical stimulation plays a vital role in immune response and tissue repair, offering therapeutic potential.