Eh. Lee et al., Overexpression of the transforming growth factor-beta-inducible gene beta ig-h3 in anterior polar cataracts, INV OPHTH V, 41(7), 2000, pp. 1840-1845
PURPOSE. In anterior polar cataracts and the fibrosis that can occur after
cataract surgery, lens epithelial cells synthesize abundant extracellular m
atrix molecules and transdifferentiate into myofibroblast-like cells. Trans
forming growth factor (TGF)-beta has been implicated as a key player in the
se cataractous changes. The purpose of this study was to determine whether
the TGF-beta-inducible gene h3 (beta ig-h3) is expressed in lens epithelial
cells from patients with anterior polar cataracts and to test whether beta
ig-h3 is induced by TGF-beta in cultured lens epithelial cells.
METHODS. Lens epithelial cells attached to the anterior capsules of human c
ataractous lenses and noncataractous lenses were examined for the expressio
n of beta ig-h3 mRNA and protein using reverse transcription-polymerase cha
in reaction and immunohistochemical analyses. The effect of TGF-beta on bet
a ig-h3 gene expression was also tested in human lens epithelial B-3 cells
using Northern and Western blot analyses.
RESULTS. beta ig-h3 mRNA was not detected in lens epithelial cells from pat
ients with clear lenses or patients with nuclear cataracts. Significant exp
ression of mRNA for beta ig-h3 was observed in lens epithelial cells from p
atients with anterior polar cataracts. Immunohistochemical analysis using a
nti-beta ig-h3 antiserum indicated that beta ig-h3 protein was present with
in the subcapsular plaques of anterior polar cataracts. Treatment of human
lens epithelial B-3 cells with TGF-beta 1 led to an increase in beta ig-h3
mRNA and the secretion of beta ig-h3 protein into the culture medium.
CONCLUSIONS. beta ig-h3 may serve as a marker for anterior polar cataracts
in addition to previously known proteins, fibronectin, type I collagen, and
ct-smooth muscle actin. The functions of this protein in lens pathology ne
ed to be further investigated.