Abstract
Purpose: :
Plasma Membrane Calcium-ATPase Isoform 4 (PMCA4) plays a critical role in the regulation of intracellular calcium concentration. The extracellular calcium-sensing receptor (CaR) regulates extracellular calcium concentration and may indirectly regulate E-cadherin interaction between epithelial cells. The purpose of this investigation is to characterize the distribution of PMCA4 and CaR in corneal epithelium (CE).
Methods: :
Cornea specimens from human and bovine donors were collected. The distribution of PMCA4 and CaR was determined by evaluating immunoreactivity (IR) in CE cryostat sections using PMCA4 isoform-specific and CaR-specific antibodies and confocal microscopy.
Results: :
In both human and bovine CE, PMCA4 IR was detected in the plasma membrane of all cells and in all layers of CE, with a lack of IR along the basal epithelial cell membranes adjacent to the basal lamina. In human CE, CaR IR was identical to that of PMCA4 IR. CaR IR in bovine CE was mostly on the cell membranes of wing and squamous cells, and occasionally on the apical and superolateral portions of basal cell. Like PMCA4 IR in bovine CE, there was an absence of CaR IR along the basal epithelial cell membranes adjacent to the basal lamina.
Keywords: calcium • cornea: epithelium • gene/expression