WNT Signaling Modifies Barrier Functions of Junctional and Pocket Epithelium

Area of Science:

• Periodontology
• Epithelial Biology
• Wnt Signaling Pathway

Background:

• Periodontitis involves disruption of the junctional epithelium (JE) barrier.
• Wnt signaling plays a crucial role in epithelial homeostasis and repair.
• Understanding JE barrier function is key to developing effective periodontitis treatments.

Purpose of the Study:

• To investigate how ligature-induced periodontitis (LIP) affects JE barrier functions.
• To determine the necessity of Wnt signaling for JE barrier integrity using genetic models.
• To evaluate the therapeutic potential of WNT3A in restoring pocket epithelium barrier functions.

Main Methods:

• Utilized a murine model of ligature-induced periodontitis (LIP).
• Employed genetic approaches (Axin2CreERT2, K14CreERT2;Wlsfl/fl mice) to assess Wnt signaling roles.
• Quantified epithelial apoptosis, attachment proteins, inflammation, and bone resorption.
• Tested liposomal WNT3A (L-WNT3A) for therapeutic effects on pocket epithelium repair.

Main Results:

• LIP induced epithelial apoptosis, reduced key attachment proteins (laminin 5, β4 integrin), and disrupted Wnt-responsive cells.
• JE was converted into pocket epithelium with compromised barrier functions, even after reepithelialization.
• Epithelial Wntless (Wls) deletion confirmed Wnt signaling's necessity for JE barrier maintenance.
• L-WNT3A treatment increased hemidesmosomal protein expression and reduced inflammation in pocket epithelium.

Conclusions:

• LIP severely impairs JE barrier function, leading to pocket epithelium formation.
• Wnt signaling is a critical regulator of JE barrier integrity.
• WNT3A demonstrates potential as a therapeutic agent for early-stage periodontitis repair by restoring barrier features.