# HK2-mediated Glycolysis Inhibits Mineralization of Cementoblasts Under Compression by Suppressing the Piezo1/Wnt Signaling

## TL;DR

This study shows that HK2-mediated glycolysis reduces cementoblast mineralization under compression by blocking Piezo1/Wnt signaling, contributing to root resorption during orthodontic treatment.

## Contribution

A novel cell compression model using PTFE buffer membrane and the discovery of HK2's role in suppressing Piezo1/Wnt signaling during cementoblast mineralization under compression.

## Key findings

- HK2-mediated glycolysis increased under compression, reducing Piezo1 and mineralization markers.
- Piezo1 activation enhanced Wnt signaling and mineralization, while its knockdown reversed these effects.
- Inhibiting HK2 partially restored Piezo1 and mineralization markers under compression.

## Abstract

Background: Orthodontically induced inflammatory root resorption (OIIRR) is a prevalent and severe complication during orthodontic tooth movement (OTM). Glycolysis plays a crucial role in the inflammatory responses. This study aimed to improve the cell compression model and investigate whether Hexokinase 2 (HK2)-mediated glycolysis regulates cementoblasts' mineralization through the mechanosensitive Piezo1/Wnt signaling under compressive force.

Methods: Mouse cementoblasts (OCCM-30) were cultured under compressive force with different buffer membranes to mimic the periodontal membrane. The flow cytometry and CCK-8 assay were utilized to evaluate cell apoptosis and viability. Piezo1 and HK2 were knocked down by small interfering RNA (siRNA). The level of Wnt/β-catenin signaling was detected by qRT-PCR and Western blotting, and the cellular localization of β-catenin was detected by immunofluorescence staining.

Results: The viability and apoptosis of cementoblasts showed no significant change under compression at 2.0 g/cm2 for 12 hours with Polytetrafluoroethylene (PTFE) buffer membrane. HK2-mediated glycolysis was increased in compressed cementoblasts with elevated ratio of the receptor activator of nuclear factor kappa-B ligand/osteoprotegerin (RANKL/OPG) and decreased expression of Piezo1 and mineralization-related markers. The Piezo1 activated Wnt signaling by increasing the nuclear translocation of β-catenin, which increased the levels of mineral-related markers. Whereas, knockdown of Piezo1 showed the opposite trend. Knockdown of HK2 to inhibit glycolysis partially reversed the compression-induced decline in Piezo1 and mineralization-related markers, as well as the rise in the RANKL/OPG ratio.

Conclusions: The cell compression model with PTFE buffer membrane effectively reduced cell damage. HK2-mediated glycolysis inhibited mineralization and enhanced osteoclast induction in cementoblasts under compression by suppressing the mechanosensitive Piezo1/Wnt signaling.