Abstract
Purpose: :
Integrins are hypothesized to plays a significant role in Posterior Capsular Opacification (PCO). However, the identity and function of the integrins participating in this process are poorly understood. The aim of this study is to determine which integrin subunits are expressed in lens epithelial cells before and after lens surgery/injury and to investigate their functions in lens biology.
Methods: :
Lens fiber cells were surgically removed from three month old C57Bl/6 mice. The expression levels of different integrin subunits were analyzed by immunofluorescence at 0hrs and 48hrs post surgery. The function of V containing integrins in the lens was assessed by mating mice harboring a floxed allele of V integrin with the MLR10 line of mice expressing CRE in all lens cells. These mice were characterized phenotypically while PCR and immunofluorescence was used to confirm the deletion of V integrin in the lens.
Results: :
As expected, lens epithelial cells upregulated the expression of -smooth muscle actin (SMA) and β1 integrin 48hrs post surgery. The β8, β5, V, and 5 subunits were also overexpressed 48hrs post surgery, however, the extent of this upregulation was less than that observed for β1 integrin. In contrast, 1, 2, 3, 6 and β2 subunit expression in lens epithelial cells 48hrs post surgery was similar to that observed 0hrs post surgery. Mice lacking V-integrin subunits in lens were created using a conditional knockout approach. Immunofluorescence analysis showed a near total loss of the V subunits from putative null lenses although PCR indicated that the deletion was not 100%. Lenses lacking V-integrin subunits are transparent until at least 5 months of age with no apparent morphological abnormalities.
Conclusions: :
V containing integrins are normally found in the lens epithelium and their expression was upregulated in these cells 48hrs after fiber cell removal. Despite this, V-integrins do not appear to be crucial for normal lens development.
Keywords: posterior capsular opacification (PCO) • posterior capsular opacification (PCO) • cataract