MMP2 Activity is Critical for TGFβ2-Induced Matrix Contraction—Implications for Fibrosis

Abstract

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)

Experimental models for posterior capsule opacification research

“…This is comparable to studies on human capsular bag models that have also revealed up-regulation of MMPs 2 and 9 following exposure to TGFb2 and the presence of MMP2 in ex vivo tissue from PCO patients (Wormstone et al, 2002b), and inhibition of MMP2 in prevention of TGFb2-induced capsular wrinkling (Eldred et al, 2012). In contrast, research by Lee et al (2002) have shown that rather than promoting cell proliferation TGFb induces apoptotic cell death of HLEB3 cells by decreasing BCL2 levels (Lee et al, 2002).…”

“…maintain transdifferentiation and promote matrix contraction (Wormstone et al, 2006a). Furthermore, MMP2 inhibition was found to play an important role in TGFb induced changes within the capsular bag (Eldred et al, 2012).…”

“…In some cases the intention is to destroy all cells (Duncan et al, 2007, others are applied to counter matrix contraction/light scatter (Eldred et al, 2012;Wormstone et al, 2002a) or suppress growth/migration (Wormstone et al, 2001). In all cases it is important to consider delivery systems.…”

Type I Collagen Accelerates the Spreading of Lens Epithelial Cells through the Expression and Activation of Matrix Metalloproteinases

“…Because the cataract is disease of old age, embryonic cells will not completely mimic clinical situations. However, while primary lens cell cultures from aged human donors are useful, human LECs transformed virally 1,44 or non-virally 45 have been used to study the mechanisms involved in the pathogenesis of PCO. In addition, LECs derived from animals, including weanling mice 46 and chicken embryos, 47 have also been used for PCO analysis.…”

Fibrotic Modifications of the Lens Epithelium

“…This occurs because the trauma of surgery can induce expression of many TGF-β activators, such as plasmins, cathepsins, MMPs [34] and thrombospondin-1 [35] which cleave latent TGF-β precursor protein. Furthermore, TGF-β itself is capable of increasing expression of MMPs, including MMP2 which could further accelerate conversion of latent TGF-β to its active form [16,36,37]. In addition, elevated numbers of reactive oxygen species are also reported to promote TGF-β activity [38,39].…”