Overexpression of the transforming growth factor-beta-inducible gene betaig-h3 in anterior polar cataracts.
OBJECTIVE
In anterior polar cataracts and the fibrosis that can occur after cataract surgery, lens epithelial cells synthesize abundant extracellular matrix molecules and transdifferentiate into myofibroblast-like cells. Transforming growth factor (TGF)-beta has been implicated as a key player in these cataractous changes. The purpose of this study was to determine whether the TGF-beta-inducible gene h3 (betaig-h3) is expressed in lens epithelial cells from patients with anterior polar cataracts and to test whether betaig-h3 is induced by TGF-beta in cultured lens epithelial cells.


METHODS
Lens epithelial cells attached to the anterior capsules of human cataractous lenses and noncataractous lenses were examined for the expression of betaig-h3 mRNA and protein using reverse transcription-polymerase chain reaction and immunohistochemical analyses. The effect of TGF-beta on betaig-h3 gene expression was also tested in human lens epithelial B-3 cells using Northern and Western blot analyses.


RESULTS
betaig-h3 mRNA was not detected in lens epithelial cells from patients with clear lenses or patients with nuclear cataracts. Significant expression of mRNA for betaig-h3 was observed in lens epithelial cells from patients with anterior polar cataracts. Immunohistochemical analysis using anti-betaig-h3 antiserum indicated that betaig-h3 protein was present within the subcapsular plaques of anterior polar cataracts. Treatment of human lens epithelial B-3 cells with TGF-beta1 led to an increase in betaig-h3 mRNA and the secretion of betaig-h3 protein into the culture medium.


CONCLUSIONS
betaig-h3 may serve as a marker for anterior polar cataracts in addition to previously known proteins, fibronectin, type I collagen, and alpha-smooth muscle actin. The functions of this protein in lens pathology need to be further investigated.
Lee
E H
EH
Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea.
Seomun
Y
Y
Hwang
K H
KH
Kim
J E
JE
Kim
I S
IS
Kim
J H
JH
Joo
C K
CK
D000818:Animals; D000869:Anterior Eye Segment; D015152:Blotting, Northern; D015153:Blotting, Western; D019556:COS Cells; D002386:Cataract / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D017931:DNA Primers / Q000737:chemistry; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016326:Extracellular Matrix Proteins; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D007124:Immunoenzyme Techniques; D007908:Lens, Crystalline / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D000099222:betaIG-H3 Protein
D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein