Purchase this article with an account.
Scott A Bowman, Tannin A Schmidt, Judith A West-Mays; Effect of lubricin on TGFβ-induced EMT of lens epithelial cells. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2649.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Following cataract surgery, residual lens epithelial cells (LEC) that are left adhered to the capsule can undergo epithelial-to-mesenchymal transition (EMT) into myofibroblasts leading to the formation of posterior capsule opacification (PCO). Lubricin (also known as proteoglycan 4) is an endogenous boundary lubricant found in synovial fluid and at the ocular surface, and has recently been reported as a non-toxic inhibitor of cell adhesion. Our study investigates the effect of lubricin on LEC adhesion to the native capsule, as well as the effect of lubricin on TGFβ-induced EMT of LEC.
The ex vivo lens explant system was employed. Anterior lens capsules were isolated from 20-day old Wistar rat pups with epithelia attached to their endogenous matrix and maintained in culture in Medium 199. Confluent explants were co-treated with recombinant human lubricin at 35 and 70 µg/ml and recombinant human TGFβ2 at 6 ng/ml (n = 6) or left untreated (control) or treated with only lubricin (n=4) or TGFβ2 (n = 4). Western blotting and immunostaining were used to observe expression of TGFβ-induced EMT markers and DAPI stains were used to observe cell adhesion.
LEC remained adhered to the capsule following treatment with 35 µg/ml of lubricin, however pyknotic nuclei were observed in LEC treated with 70 µg/ml of lubricin, suggesting toxicity. All subsequent lubricin treatments used 35 µg/ml. Unlike control LEC explants, LEC treated with TGFβ underwent EMT, losing expression of the epithelial marker E-cadherin and exhibiting induced expression of the mesenchymal marker αSMA. In comparison, LEC co-treated with lubricin and TGFβ showed a marked decrease in E-cadherin, however, αSMA expression was significantly mitigated in comparison to LEC treated with TGFb alone. Inhibition of αSMA expression suggests lubricin can inhibit the myofibroblast phenotype.
Our findings indicate that lubricin does not alter the adhesion of LEC to the native lens capsule. Also, our results suggest that lubricin has an anti-fibrotic effect, preventing TGFβ-mediated αSMA expression in LEC. Further studies will be carried out to determine the potential therapeutic effect of lubricin in preventing PCO.
This PDF is available to Subscribers Only