Effect of TGFβ and PDGF-B blockade on corneal myofibroblast development in mice

Abstract

The purpose of this study was to investigate the role of transforming growth factor beta (TGFβ) and/or platelet-derived growth factor-B (PDGF-B) blockade on the differentiation of vimentin and alpha-smooth muscle actin (αSMA)-expressing myofibroblasts associated with haze in mice. Mouse corneas had haze-generating irregular PTK (phototherapeutic keratectomy) and topical treatment with the vectors. Six study groups of PTK treated corneas, with four corneas per group in each experiment, were Group 1) treated with TGFβ-KDEL vector interfering with TGFβ signaling through anomalous sorting of cytokine bound to the expressed altered receptor; Group 2) treated with PDGF-B-KDEL vector interfering with PDGF signaling through anomalous sorting of cytokine bound to the expressed altered receptor; Group 3) treated with both TGFβ-KDEL vector and PDGF-B-KDEL vector to interfere with signaling of both cytokines; Group 4) empty pGFPC1 vector; Group 5) empty pCMV vector; and Group 6) no vector treatment control. At one month after surgery, the corneas were analyzed by immunocytochemistry (IHC) for central stromal cells expressing myofibroblast markers vimentin and αSMA. The stroma of corneas treated with the TGFβ-KDEL vector alone (p <0.05) or both the TGFβ-KDEL and PDGF-B-KDEL vectors (P < 0.05) had significantly lower density of vimentin-positive cells compared to the corresponding control group. The central stroma of corneas treated with the TGFβ-KDEL vector (p <0.05) or the PDGF-B-KDEL vector (p < 0.05) had lower density of αSMA-positive cells compared to the corresponding control group. The density of αSMA-positive stromal cells was also significantly lower (p < 0.05) when both the TGFβ-KDEL and PDGF-B-KDEL and vectors were applied together compared to the corresponding control groups. This study provides in situ evidence that TGFβ and PDGF-B have important roles in modulating myofibroblast generation in the mouse cornea after haze-associated injury.

Myofibroblasts

“…Furthermore, PDGF has been shown to induce myofibroblast activation in the eye directly or in synergy with TGF-β1 (Jester et al, 2002), also recently shown for bone-marrow derived precursors (Singh et al, 2014), which results the in loss of crystalline production in keratocytes (LaGier et al, 2013). Likewise, blocking PDGF action inhibits corneal myofibroblast activation (Kaur et al, 2009b;Singh et al, 2011).…”

Cellular and extracellular matrix modulation of corneal stromal opacity

“…The development of myofibroblasts has been well characterized with in vitro models and in animal models following photorefractive keratotomy (PRK) (Jester et al, 1999c; Masur et al, 1996; Mohan et al, 2003; Mohan et al, 2008; Singh et al, 2011; Singh et al, 2014b). In vitro studies have demonstrated that TGFβ is a key cytokine in the development of corneal myofibroblasts (Jester et al, 1999a; Masur et al, 1996; Singh et al, 2014b).…”

NF-κB Mediates the Survival of Corneal Myofibroblast Induced by Angiotensin II

“…Firstly, repair of corneal epithelial basement membrane and restoration of basement membrane barrier function lead to stromal withdrawal of epithelial-derived TGFb, and possibly other cytokines such as platelet-derived growth factor (PDGF), which are important for phenotype transformation and viability maintenance of myofibroblast, and in turn induce corneal myofibroblast apoptosis. 10,[27][28][29][30] Secondly, many cytokines including IL-1, TNFa, and platelet-activating factor (PAF) play active roles in the elimination of myofibroblasts by activating apoptosis related signaling pathway. 8,9 In this study, we used two different models of apoptosis, in which treatment with TNFa plus CHX or serum starvation was used, respectively, to imitate the in vivo condition that corneal myofibroblasts undergo apoptosis.…”