TGF-β2-induced matrix modification and cell transdifferentiation in the human lens capsular bag

PURPOSE. To study the role of TGF-β2 in posterior capsule opacification (PCO) and to determine whether CAT-152 (lerdelimumab), a fully human monoclonal antibody that neutralizes the effect of TGF-β2, can also provide therapeutic benefit for PCO. METHODS. In vitro capsular bags were prepared from human donor eyes and maintained in a 5% CO₂ atmosphere at 35°C. To investigate expression of active TGF-β2, capsular bags were incubated in serum-free EMEM for 2, 28, or more than 100 days and analyzed by ELISA (n ≥ 4 at each time point). To study underlying mechanisms, match-pair experiments were also performed, so that the medium was supplemented with 0, 1 or 10 ng/mL TGF-β2 with or without 10 μg/mL CAT-152 (n = 4 in all cases). On-going observations were by phase-contrast microscopy. In addition, donor material from patients who had undergone cataract surgery was analyzed. Cellular architecture was examined by fluorescence cytochemistry. Expression of matrix metalloproteinase (MMP)-2 and -9 was assessed by gelatin zymography. RESULTS. Analysis of capsular bags from donor eyes that had received an intraocular lens (IOL) revealed the presence of endogenous active TGF-β2, matrix wrinkling, and expression of transdifferentiation markers αSMA and fibronectin. When cultured in vitro, donor bags also showed sustained release of MMP-2 and -9. Culture of capsular bags prepared in vitro from whole lenses showed that TGF-β2 (1-10 ng/mL) stimulated transdifferentiation and contraction of the capsular bag, resulting in light scatter. TGF-β2 also induced sustained release of MMP-2 and -9. Active TGF-β2 was detected in these cultures. The human monoclonal anti-TGF-β2 antibody CAT-152 (10 μg/mL) effectively inhibited all TGF-β2-induced effects. CONCLUSIONS. Addition of TGF-β2 accelerates transdifferentiation and contraction of the capsular bag, resulting in light scatter. CAT-152 inhibited all the effects of TGF-β2 that were examined and therefore has the potential to suppress development of PCO and provide potential therapeutic benefit to cataract patients.