The Ca2 + / nucleotide nanocomplex formulation enhances the pump function of corneal endothelial cells by increasing the activity of Na + / K + dependent ATPase

Session Details

Session Title: Presented Poster Session: Cornea: Medical

Venue: Poster Village: Pod 2

First Author: : K.Kang SOUTH KOREA

Co Author(s): :    J. Jeung   H. Hwang   S. Kim                 

Abstract Details

Purpose:

Na, K-ATPase exist in the membrane of the corneal endothelial cell and control the corneal hydration through the pump function. It also plays an important role in preserving the transparency of the cornea. In this study, we investigated the effect of Ca2+/ Nucleotide (NT) nanocomplex (NC) on Na, K-ATPase and the pump function of the corneal endothelial cells.

Setting:

Department of Ophthalmology, Incheon St. Mary’s Hospital, The Catholic University of Korea, Incheon, Korea

Methods:

Bovine corneal endothelial cells were used, and the cells were treated with Ca2+/ Nucleotide (NT) nanocomplex (NC) formulation after various insults. Na, K-ATPase activity was measured by the spectrophotometric measurement of phosphate released from ATP with the use of ammonium molybdate. The Na, K-ATPase activity was calculated as the difference in ATPase activity between cells exposed to ouabain and those not exposed. Ussing chamber was used to measure the pump function of endothelial cells. Western blot analysis and immunocytochemistry were performed to measure the expression of Na, K-ATPase α1 subunit.

Results:

The Ca2+/NT/NCs were prepared at a [Ca2+]:[NT]:[bPEI 1.8kDa] ratio of 0.25mM: 0.5.mM: 1.0mM and these preparations significantly and gradually increased the activity of Na, K-ATPase in bovine corneal endothelium. These effects were blocked by the PKC inhibitor. Ca2+/NT/NCs increased the viability of cells exposed to a low temperature (4℃) for 4 or 8 hours(p<0.05). Western blot analysis indicated that Ca2+/NT/NCs formulation significantly decreased the ratio of inactive Na, K-Atpase α1 subunit(after 12 hours of incubation with 0.5mM of Ca2+/NT/NCs formation). Immunocytochemistry reveals that Ca2+/NT/NCs formulation increased the cell surface expression of the Na,K-ATPase α1 subunit.

Conclusions:

This study demonstrates that the Ca2+ NT NC formulation increases the activity of Na, K-ATPase in the corneal endothelial cells to enhance the pump function. Our results imply a potential therapeutic strategy that the pumping function of the corneal endothelial cells can be improved by the administration of Ca2+ NT NC formulation, which may help to maintain and improve transparency of the cornea. Further experiments are to be carried out to confirm the practical effect of the Ca2+ NT NC formulation in vivo.

Financial Disclosure:

None