IADR Abstract Archives

Modulation of Tooth Formation through G Protein-Coupled Receptor (GPCR) Signaling

Objective: 

GPCR-mediated G-protein signaling orchestrates crucial intercellular communications during the development of multicellular organs such as mammary glands, brain, liver, and bone. Tooth development is also governed by communication between epithelial and mesenchymal cells. We aim to identify target GPCRs with greater expression in developing teeth than in vital organs such as brain/liver to enable tooth-specific pharmacologic targeting, and to modulate tooth formation through the GPCR signaling.

Method: 

To identify the target GPCRs, we compared RNA sequencing data derived from teeth, brain and liver in E13.5 wild-type mice. To identify potential ligands, we constructed atomic models for the corresponding protein sequences, bioinformatically mapped all compounds co-crystallized with GPCRs, chemoinformatically compared them to small molecules and FDA-approved drugs, and evaluated for molecular fit. To examine if altered G-protein signals can affect tooth formation, transgenic mice were developed to express Rs1, an engineered GPCR that constitutively activates stimulatory G-protein (Gs) signaling, in dental epithelial cells using the cytokeratin-5 promoter. Jaws from the Rs1 and wild-type mice were processed for immunohistochemistry.

Result: 

Gs protein expression in wild-type mice was greater in the developing tooth buds than in adjacent tissues. We found that increased Gs signaling in dental epithelial cells induced the development of supernumerary teeth in K5/Rs1 mice. Twenty GPCRs were highly expressed in E13.5 developing teeth with at least two-fold greater expression. Structural analysis indicates that over 100 drugs are predicted to interact with these GPCRs. The 5HTR1b protein, a GPCR similar to the Rs1, was also found to be expressed highly in odontogenic epithelial cells and at higher levels in teeth as compared to liver (3.9-fold) and brain (390-fold). Pharmacological activationof the 5HTR1b in wild-type mice resulted in supernumerary incisor formation as seen in the K5/Rs1 mice.

Conclusion:

Differential expression of GPCRs in developing teeth will enable pharmacological manipulation to specifically control tooth formation.

AADR/CADR Annual Meeting
2014 AADR/CADR Annual Meeting (Charlotte, North Carolina)
Charlotte, North Carolina
2014
17
Craniofacial Biology
  • Clarot, Samuel  ( University of California - San Francisco, San Francisco, CA, USA )
  • Howell, Sheena  ( University of California - San Francisco, San Francisco, CA, USA )
  • Kasi, Archana  ( University of California - San Francisco, San Francisco, CA, USA )
  • Klein, Ophir  ( University of California - San Francisco, San Francisco, CA, USA )
  • Hsiao, Edward  ( University of California - San Francisco, San Francisco, CA, USA )
  • Horst, Jeremy  ( University of California - San Francisco, San Francisco, CA, USA )
  • Horst, Orapin  ( University of California - San Francisco, San Francisco, CA, USA )
    • Oral Session
    Dental and Craniofacial Morphogenesis
    03/19/2014