Investigative ophthalmology & visual science
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Invest. Ophthalmol. Vis. Sci. · May 2003
Response of lens epithelial cells to injury: role of lumican in epithelial-mesenchymal transition.
Lens epithelial cells (LECs) undergo epithelial-mesenchcymal transition (EMT) after injury and transform into myofibroblasts positive for alpha-smooth muscle actin (alphaSMA), an established marker of this process. Lumican is a keratan sulfate proteoglycan core protein. This study was conducted to examine whether human and mouse LECs express lumican after injury. To determine whether lumican may modulate EMT of LECs in response to injury or to exposure to transforming growth factor-beta2 (TGFbeta2), alphaSMA expression by the LECs was examined in lumican (Lum)-knockout mice in vivo and in organ culture. ⋯ Human capsular opacification contains lumican, and mouse LECs upregulate lumican and alphaSMA in response to injury. Loss of lumican perturbs EMT of mouse LECs.
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Invest. Ophthalmol. Vis. Sci. · May 2003
Connective tissue growth factor expression and action in human corneal fibroblast cultures and rat corneas after photorefractive keratectomy.
Connective tissue growth factor (CTGF) has been linked to fibrosis in several tissues. In this study, the interactions between CTGF and transforming growth factor (TGF)-beta were assessed in human corneal fibroblasts, and the levels and location of CTGF protein and mRNA were measured during healing of excimer laser ablation wounds in rat corneas. ⋯ These data demonstrate that CTGF is expressed by corneal cells after stimulation by TGF-beta, that CTGF expression increases significantly during corneal wound healing, and that CTGF mediates the effects of TGF-beta induction of collagen synthesis by corneal fibroblasts. These data support the hypothesis that CTGF promotes corneal scar formation and imply that regulating CTGF synthesis and action may be an important goal for reducing corneal scarring.