Purchase this article with an account.
Ernest F. Talarico, Jr., Nancy J. Mangini; Plasma Membrane Calcium-ATPase Isoform-4 Plays a Role in Corneal Epithelial Wound Healing. Invest. Ophthalmol. Vis. Sci. 2011;52(14):2039.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Plasma Membrane Calcium-ATPase (PMCA) is essential for control of intracellular Ca2+ concentration. In humans, four genes encode PMCA proteins termed PMCA1 - PMCA4. PMCA4 is the major PMCA isoform expressed in human corneal epithelium (CE); however, little is known about its role. The present work examined the functional role of PMCA4 during CE wound healing.
Wounds were produced in the central CE of rabbits using the n-heptanol technique. PMCA4 distribution was examined by immunohistochemical staining of frozen sections using PMCA4-specific antibody at 6, 24, 36 and 48 h post-injury. PMCA4 localization was evaluated by calculating the percentage of basal epithelial cells showing immunoreactivity (IR) along apical vs. basal membranes. The role of PMCA4 in wound healing was studied in human telomerase-immortalized corneal epithelial cells (hTCEpi) after transfection with siRNAPMCA4. Cell cultures were wounded 48 h after transfection, and the wound area was measured at 3-h intervals for 30 h. Data were plotted as wound area vs. time post-wounding.
PMCA4 IR in control CE was observed in the plasma membrane of all cells and in all layers of CE, with a lack of IR along the cell membranes of basal epithelial cells adjacent to the basal lamina. During the lag phase of wound healing (6 h), PMCA4 IR was seen mostly along apical membranes of basal epithelial cells near the wound margin, with little IR along basal plasma membranes. During the migration phase (24 h), PMCA4 IR was found mostly on basal cell membranes adjacent to the basal lamina. After wound closure (36 - 48 h), PMCA4 IR was again found primarily on the apical membrane of basal epithelial cells. The wound area in siRNAPMCA4-transfected hTCEpi cells failed to seal whereas wounds in cultures transfected with scrambled construct completely closed.
PMCA4 distribution in basal epithelial cell membranes changes during CE wound healing. Knockdown of PMCA4 expression in hTCEpi cells slows wound healing in a cell culture model. These findings suggest PMCA4 redistribution is one factor mediating calcium-regulated events necessary for cell migration in regenerating CE.
This PDF is available to Subscribers Only