Abstract
The goal of this study was to investigate how alterations in extracellular matrix (ECM) biophysical properties modulate corneal keratocyte phenotypes in response to specific wound healing cytokines and Rho GTPases. Rabbit corneal keratocytes were plated within standard collagen matrices (2.5 mg/mL) or compressed collagen matrices (~100 mg/mL) and cultured in serum-free media, PDGF BB, IGF, FGF2 or TGFβ1, with or without the Rac1 inhibitor NSC23766 and/or the Rho kinase inhibitor Y-27632. After 1 to 4 days, cells were labeled for F-actin and imaged using confocal microscopy. Keratocytes within standard collagen matrices (which are highly compliant) maintained a dendritic phenotype following culture in serum-free media, PDGF, IGF and FGF, but developed stress fibers in TGFβ1. Keratocytes within compressed collagen (which has high stiffness and low porosity) maintained a dendritic phenotype following culture in serum-free media, PDGF and IGF, but developed stress fibers in both FGF and TGFβ1. The Rac inhibitor had no significant impact on growth factor responses in compliant matrices. Within compressed collagen matrices however, the Rac inhibitor induced fibroblastic transformation in serum-free media, PDGF and IGF. Fibroblast and myofibroblast transformation was blocked by Rho kinase inhibition. Overall, keratocyte growth factor responses appear to be regulated by both the interplay between Rho and Rac signaling, and the structural and mechanical properties of the ECM.
Highlights
The cornea is an optically clear tissue that forms the front surface of the eye, and accounts for approximately two-thirds of its refractive power
Keratocytes exposed to PDGF BB (Figure 2B) and insulin growth factor (IGF) (Figure 2C) maintained this dendritic morphology, with cortical F-actin and no stress fibers
Consistent with the results of the current study (Table 3), it was demonstrated that keratocytes cultured in insulin growth factor (IGF) or PDGF BB
Summary
The cornea is an optically clear tissue that forms the front surface of the eye, and accounts for approximately two-thirds of its refractive power. Quiescent corneal keratocytes adjacent to the injury transform into an activated, fibroblastic repair phenotype [7,8] These activated fibroblasts proliferate, migrate into the provisional matrix, and generate the forces required for wound closure and/or ECM remodeling. Fibroblasts further differentiate into myofibroblasts, which generate even stronger forces and synthesize fibrotic ECM components [9,10]. These wound healing responses can cause a permanent reduction in corneal clarity by increasing light scattering, and can alter the refractive effect of vision correction surgeries such as photorefractive keratectomy (PRK) by changing corneal shape and/or thickness [11,12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
