It is well established that the proto-oncogene, bcl-2, can prevent apoptosis induced by a variety of factors. Regarding the mechanism by which BCL-2 prevents cell death, one theory suggests that it acts by protecting cells from oxidative stress. In the lens system, oxidative stress-induced apoptosis is implicated in cataractogenesis. To explore the possibility of anti-apoptotic gene therapy development for cataract prevention and also to further test the anti-oxidative stress theory of BCL-2 action, we have introduced the human bcl-2 gene into an immortalized rabbit lens epithelial cell line, N/N1003A. The stable expression clones of both vector-and bcl-2-transfected cells have been established. Treatment of the two cell lines with H 2 O 2 revealed that bcl-2-transfected cells were less capable of detoxifying H 2 O 2 than the control cells. Moreover, bcl-2-transfected cells are more susceptible to H 2 O 2 -induced apoptosis. To explore why bcl-2-transfected cells have reduced resistance to H 2 O 2 -induced apoptosis, we examined the expression patterns of several relevant genes and found that expression of the ␣B-crystallin gene was distinctly downregulated in bcl-2-transfected cells compared with that in vector-transfected cells. This down-regulation was specific because a substantial inhibition of BCL-2 expression through antisense bcl-2 RNA significantly restored the level of ␣B-crystallin and, moreover, enhanced the ability of the bcl-2-transfected cells against H 2 O 2 -induced apoptosis. Introduction of a mouse ␣B-crystallin gene into bcl-2-transfected cells also counteracted the BCL-2 effects. Down-regulation of ␣B-crystallin gene was largely derived from changed lens epithelial cell-derived growth factor activity. Besides, ␣B-crystallin prevents apoptosis through interaction with procaspase-3 and partially processed procaspase-3 to prevent caspase-3 activation. Together, our results reveal that BCL-2 can regulate gene expression in rabbit lens epithelial cells. Through down-regulation of the ␣B-crystallin gene, BCL-2 attenuates the ability of rabbit lens epithelial cells against H 2 O 2 -induced apoptosis.

No abstract

No abstract

No abstract

The dietary component SFN demonstrates an ability to protect human lens cells against oxidative stress and thus could potentially delay the onset of cataract.

No abstract

A targeted inhibition approach demonstrated that key elements associated with transdifferentiation are not critical for TGFbeta-induced matrix contraction.

PURPOSE. The fibrotic lens disorder posterior capsule opacification (PCO) develops in millions of patients following cataract surgery. PCO characteristics are extensive extracellular matrix (ECM) production and contraction of the posterior lens capsule, resulting in light-scattering ECM modification (wrinkling). The pro-fibrotic cytokine transforming growth factor beta (TGFb) is central to PCO development. This study aimed to elucidate the role of the ECM modulators matrix metalloproteinases (MMPs) in TGFb-mediated PCO formation. METHODS.The human lens epithelial cell-line FHL-124 and human capsular bag models were employed. Gene expression of MMP family members was determined by oligonucleotide microarray and quantitative real-time RT-PCR. MMP2 and MT1-MMP protein levels were analyzed by ELISA and Western blotting, respectively. Matrix contraction was determined using an FHL-124 patch contraction assay; at end-point, cells were stained with Coomassie brilliant blue and area was determined using image analysis software. Cell coverage and wrinkle formation on the posterior capsule were also assessed using human capsular bag models.RESULTS. Active TGFb2 (10 ng/mL) increased gene and protein levels of MMP2 and MT1-MMP and induced matrix contraction in FHL-124 cells. Specific siRNA inhibition of MT1-MMP did not suppress TGFb2-induced matrix contraction. Active TGFb2-mediated contraction was prevented by broad-spectrum MMP inhibitor GM6001 (25 lM), MMP2 siRNA, and MMP2 neutralizing antibody (4 lg/mL). TGFb2-induced wrinkle formation was attenuated in human capsular bags treated with MMP2 neutralizing antibody (20 lg/mL).CONCLUSIONS. MMP2 plays a critical role in TGFb2-mediated matrix contraction, which appears to be independent of MT1-MMP. MMP2 inhibition provides a novel strategy for the treatment of PCO and potentially other fibrotic disorders. (Invest Ophthalmol Vis Sci. 2012;53:4085-4098)