Scientists Discover an Epigenetic Mechanism That Protects Tooth Cells from Mechanical Stress

Researchers at the University of Southern California have identified a previously unknown epigenetic mechanism that protects tooth tissue progenitor cells from damage caused by mechanical stress and helps sustain the long-term renewal of mineralized tissues.

The study, published in the journal Bone Research, revealed the existence of a biological “mechanostat” — a regulatory system that controls how strongly cells respond to physical pressure.

The work was conducted using continuously growing mouse incisors, an ideal model for studying regeneration because they are constantly subjected to chewing forces and wear. The researchers combined genetic models, gene-expression analysis, chromatin studies, calcium-signaling imaging, and mechanical-loading experiments.

The scientists focused on the enzyme KDM6B, which regulates gene activity by modifying chromatin structure. They found that KDM6B is particularly active in rapidly dividing progenitor cells responsible for generating tooth tissues.

When the Kdm6b gene was disabled in mice, the animals developed significant tooth-growth abnormalities under mechanical stress, including slower growth, thinner dentin, enlarged pulp cavities, and defects in the formation of odontoblasts—the cells that produce dentin.

Further analysis revealed that the absence of KDM6B makes cells excessively sensitive to mechanical forces. This occurs through uncontrolled activation of the mechanosensitive ion channel PIEZO1, which converts physical pressure into calcium signals within the cell. The resulting calcium overload leads to the death of progenitor cells.

The researchers discovered that under normal conditions, KDM6B regulates the expression of the Bmi1 gene by removing the repressive chromatin mark H3K27me3. The BMI1 protein then suppresses PIEZO1 activity. When this regulatory pathway is disrupted, a cascade of events is triggered that ultimately damages cells exposed to mechanical stress.

Experiments showed that reducing mechanical loading or restoring specific components of the pathway could partially normalize tissue growth and improve tooth structure.

According to the researchers, this mechanism functions as an “epigenetic mechanostat,” balancing beneficial and harmful cellular responses to physical pressure. Although the study focused on dental tissues, similar regulatory systems may also exist in bones, cartilage, and other mechanically stressed tissues throughout the body.

The authors believe the discovery could contribute to the development of new treatments for degenerative diseases affecting the skeleton and oral tissues, while also advancing regenerative medicine strategies aimed at repairing damaged tissues.

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