Antisense to MDR1 mRNA reduces P-glycoprotein expression swelling-activated Cl− current and volume regulation in bovine ciliary epithelial cells

摘要

class="enumerated" style="list-style-type:decimal">Native ciliary epithelial cells from the ciliary epithelium of the eye exhibit anti-P-glycoprotein (P-gp) immunofluorescence.We have used an antisense ‘knock-down’ approach to investigate the relationship between P-gp and the volume-activated chloride current (ICl,swell) and its role in volume regulation.An antisense oligonucleotide to the human multidrug resistance (MDR1) gene, taken up by the cells in a dose-dependent manner, reduced P-gp immunofluorescence, inhibited ICl,swell and significantly increased the latency of activation of ICl,swell.Increasing the hypotonic stress did not result in an increased activation of ICl,swell. MDR1 antisense ‘knock-down’ also reduced the ability of the cells to volume regulate following a hypotonic challenge.These cells are known to express at least two volume-activated chloride channels, and the data suggest that P-gp is involved in the activation pathway of a subset of channels that contribute to whole-cell ICl,swell and participate in volume regulation.