A rabbit corneal epithelial cell line expresses functional platelet-derived growth factor beta-type receptors

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M Knorr1, K P Steuhl, D Tatje

  • 1Department of General Ophthalmology, University of Tübingen, Germany.

Investigative Ophthalmology & Visual Science
|June 1, 1992
PubMed

Insights

Platelet-derived growth factor (PDGF) isoforms AB and BB stimulate calcium release in rabbit corneal cells by binding to beta-type receptors. This calcium signal occurs independently of extracellular calcium.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Platelet-derived growth factor (PDGF) is crucial for mesenchymal cell proliferation.
  • PDGF exists in three isoforms: PDGF-AA, PDGF-AB, and PDGF-BB.
  • Cell surface receptors, alpha-type and beta-type, mediate PDGF signaling.

Purpose of the Study:

  • To investigate the effects of different PDGF isoforms on rabbit corneal epithelial cells (SIRC).
  • To determine the role of PDGF receptors in mediating cellular responses.
  • To analyze the impact of extracellular calcium on PDGF-induced signaling.

Main Methods:

  • Utilized a rabbit corneal epithelial cell line (SIRC).
  • Quantified the expression of PDGF alpha-type and beta-type receptors on SIRC cells.
  • Measured cytosolic free calcium levels in response to PDGF isoforms.

Main Results:

  • SIRC cells express significantly more beta-type PDGF receptors than alpha-type receptors.
  • PDGF-AB and PDGF-BB isoforms induced a dose-dependent increase in cytosolic free calcium.
  • The effective dose for 50% of cells (ED50) for calcium rise was 5 ng/ml.
  • The PDGF-induced calcium signal was largely independent of extracellular calcium.

Conclusions:

  • PDGF-BB and PDGF-AB are the active isoforms signaling through beta-type receptors in SIRC cells.
  • The observed calcium flux is primarily an intracellular event.
  • These findings contribute to understanding corneal cell response to growth factors.

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