Dental enamel cells express functional SOCE channels

Sci Rep. 2015 Oct 30;5:15803. doi: 10.1038/srep15803.

Abstract

Dental enamel formation requires large quantities of Ca(2+) yet the mechanisms mediating Ca(2+) dynamics in enamel cells are unclear. Store-operated Ca(2+) entry (SOCE) channels are important Ca(2+) influx mechanisms in many cells. SOCE involves release of Ca(2+) from intracellular pools followed by Ca(2+) entry. The best-characterized SOCE channels are the Ca(2+) release-activated Ca(2+) (CRAC) channels. As patients with mutations in the CRAC channel genes STIM1 and ORAI1 show abnormal enamel mineralization, we hypothesized that CRAC channels might be an important Ca(2+) uptake mechanism in enamel cells. Investigating primary murine enamel cells, we found that key components of CRAC channels (ORAI1, ORAI2, ORAI3, STIM1, STIM2) were expressed and most abundant during the maturation stage of enamel development. Furthermore, inositol 1,4,5-trisphosphate receptor (IP3R) but not ryanodine receptor (RyR) expression was high in enamel cells suggesting that IP3Rs are the main ER Ca(2+) release mechanism. Passive depletion of ER Ca(2+) stores with thapsigargin resulted in a significant raise in [Ca(2+)]i consistent with SOCE. In cells pre-treated with the CRAC channel blocker Synta-66 Ca(2+) entry was significantly inhibited. These data demonstrate that enamel cells have SOCE mediated by CRAC channels and implicate them as a mechanism for Ca(2+) uptake in enamel formation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ameloblasts / metabolism
  • Ameloblasts / pathology
  • Animals
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / chemistry
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Calcium Signaling / drug effects
  • Calcium-Binding Proteins / chemistry
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism
  • Cells, Cultured
  • Dental Enamel / cytology
  • Dental Enamel / metabolism*
  • Fura-2 / chemistry
  • Fura-2 / metabolism
  • Humans
  • Inositol 1,4,5-Trisphosphate Receptors / genetics
  • Inositol 1,4,5-Trisphosphate Receptors / metabolism
  • Male
  • Membrane Glycoproteins / chemistry
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • ORAI1 Protein
  • Rats
  • Rats, Sprague-Dawley
  • Ryanodine Receptor Calcium Release Channel / genetics
  • Ryanodine Receptor Calcium Release Channel / metabolism
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases / genetics
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases / metabolism
  • Stromal Interaction Molecule 1
  • Stromal Interaction Molecule 2
  • Thapsigargin / pharmacology

Substances

  • Atp2a2 protein, rat
  • Calcium Channel Blockers
  • Calcium Channels
  • Calcium-Binding Proteins
  • Inositol 1,4,5-Trisphosphate Receptors
  • Membrane Glycoproteins
  • Membrane Proteins
  • ORAI1 Protein
  • Orai1 protein, rat
  • Ryanodine Receptor Calcium Release Channel
  • STIM2 protein, rat
  • Stim1 protein, rat
  • Stromal Interaction Molecule 1
  • Stromal Interaction Molecule 2
  • Thapsigargin
  • Sarcoplasmic Reticulum Calcium-Transporting ATPases
  • Fura-2