Abstract
Purpose:
To study expression pattern of cell junction proteins Cx43, ZO-1, N-cadherin, α-catenin and β-catenin in pediatric posterior capsular plaques and also to study these proteins along with MAPK/ERK pathway in vitro, in conditions mimicking that of capsular plaques.
Methods:
The study was done in accordance with declaration of Helsinki. Specimens of posterior capsule plaque (PCP) were collected from 15 pediatric patients undergoing cataract surgery. These specimens were used for the immunolocalization and real time PCR of Cx43, ZO-1, N-cadherin, α-catenin and β-catenin. In vitro experiments were done where a human lens epithelial cell line FHL124 was subjected to TGF-β2 treatment for inducing cellular changes similar to those during plaque formation. PD98059 which is a specific inhibitor of MAPK/ERK pathway was used one hour prior to TGF-β2 treatment in one of the groups. Cell junction proteins were studied by real-time PCR and western blot in all the three groups.
Results:
Immunolocalization results showed that most of the cells of PCP expressed Cx43, ZO-1, N-cadherin and β-catenin, but there were scant cells that showed α-catenin expression. Real-time PCR showed expression of Cx43, ZO-1, N-cadherin, α-catenin and β-catenin in all the specimens. In vitro study revealed that the treatment of PD98059 prior to TGF-β2 inhibited the MAPK/ERK pathway. There was significant upregulation of Cx43, N-cadherin and β-catenin in TGF-β2 treated group and inhibition of MAPK/ERK pathway significantly abrogates the increase in Cx43 and β-catenin expression caused by TGF-β2. However, it did not decrease the TGF-β2 induced upregulation in N-cadherin.
Conclusions:
Specimens of PCP showed expression of Cx43 which is a marker of lens epithelial cells and this provides further evidence that the cells of PCP are of epithelial origin. In vitro data show the possible involvement of MAPK/ERK pathway in modulating cell junction proteins in TGF-β2 treated lens epithelial cells.
Keywords: 446 cell adhesions/cell junctions •
445 cataract