Transcriptomic Classification of Neurons Innervating Teeth

Area of Science:

• Neuroscience
• Oral Biology
• Sensory Biology

Background:

• Toothache is a common consequence of dental damage and infection, often treated with endodontic therapy.
• The biological function of sensory nerve fibers innervating teeth remains incompletely understood.
• Previous studies on dental innervation relied on candidate gene approaches, limiting comprehensive analysis.

Purpose of the Study:

• To determine the transcriptomic diversity of sensory neurons innervating mouse molar teeth.
• To characterize the molecular and functional properties of these dental neurons.
• To investigate the potential roles of dental neurons in pain and mechanosensation.

Main Methods:

• Retrograde labeling of sensory neurons from mouse molar teeth.
• Transcriptomic profiling of labeled neurons to identify gene expression patterns.
• Analysis of neuronal markers, including nociceptive and mechanosensitive ion channels like Piezo2.

Main Results:

• Individual mouse molars are innervated by approximately 50 specialized trigeminal neurons.
• The majority of these neurons are fast-conducting, with two-thirds expressing nociceptive markers.
• Nearly all labeled neurons, including nociceptors, express the mechanosensor Piezo2; a quarter may be involved in discriminative touch.

Conclusions:

• Dental neurons possess diverse transcriptomic profiles, including nociceptive and potentially mechanosensitive populations.
• The mechanosensor Piezo2 is widely expressed in dental neurons, suggesting a role in tactile sensation and protective reflexes.
• Abnormal activation of these dental neurons, particularly nociceptors, may contribute to toothache.