Suppression by an RAR-γ Agonist of Collagen Degradation Mediated by Corneal Fibroblasts

Abstract

PURPOSE.To examine the role of retinoic acid receptor (RAR) isoforms in interleukin-1b (IL1b)-induced collagen degradation by corneal fibroblasts.METHODS. Primary rabbit corneal fibroblasts embedded in a three-dimensional collagen gel were incubated with or without all-trans retinoic acid (ATRA), the RAR-a agonist Am580, the RAR-b agonist AC55649, or the RAR-c agonist R667. Collagen degradation was determined by measurement of hydroxyproline produced in acid hydrolysates of culture supernatants. Matrix metalloproteinase (MMP) expression was evaluated by immunoblot analysis and gelatin zymography. The phosphorylation of mitogen-activated protein kinases (MAPKs) and the endogenous nuclear factor (NF)-jB inhibitor IjB-a was examined by immunoblot analysis. Cell proliferation was measured with a bromodeoxyuridine incorporation assay, and cell viability was determined by measurement of the release of lactate dehydrogenase. RESULTS.Interleukin-1b-induced collagen degradation by corneal fibroblasts was inhibited by ATRA, Am580, and R667 in a concentration-dependent manner but was unaffected by AC55649, with the inhibitory effects of ATRA and R667 being markedly greater than that of Am580. The IL-1b-induced production of MMP-1, MMP-2, MMP-3, and MMP-9 by corneal fibroblasts was also inhibited by R667 in a concentration-dependent manner. R667 inhibited the IL-1b-induced phosphorylation of IjB-a but not that of MAPKs. R667 had no effect on the proliferation or viability of corneal fibroblasts.CONCLUSIONS. The RAR-c agonist R667 suppressed MMP production and thereby inhibited collagen degradation by corneal fibroblasts exposed to the proinflammatory cytokine IL-1b. These effects of R667 may be mediated by the NF-jB signaling pathway.

Retinoic Acid Maintains Function of Neural Crest–Derived Ocular and Craniofacial Structures in Adult Zebrafish

“…For example, RA regulates the collagen composition and alters the balance between different collagen α chains in various cell types. 46 , 47 In the ventral angle, the collagen distribution in the extracelular matrix may be influenced by endogenous RA levels, and increased or decreased RA may have subsequent effects on aqueous outflow that are hidden by apoptosis. 48 Additional studies examining the different functions of RA are required.…”

Regulation of matrix metalloproteinases 2 and 9 in corneal neovascularization

“…Reduction of MMP-2 and MMP-9 gene expression (Rajashekhar, Shivanna, Kompella, Wang, & Srinivas, 2014;Xiao et al, 2012) RAR-β agonist AC55649 Primary rabbit corneal fibroblasts Incubation Reduction of MMP-2 and MMP-9 gene expression in a dose-dependent manner (Kimura et al, 2017) Female hormone 17β-estradiol Human corneal stromal cells Incubation Reduction of MMP-2 gene expression (Yin, Wan, Tian, Zhao, & Deng, 2018) Neuroprotectin D1 Herpes simplex virus (HSV)…”

Autocrine IL-1β mediates the promotion of corneal neovascularization by senescent fibroblasts

“…A previous report had proved that IL-1␤ inhibition represented a valuable alternative to inhibit vascular endothelial growth in the control of choroidal neovascularization caused by age-related macular degeneration (34). Moreover, IL-1␤ was shown to modulate various functions in corneal fibroblasts (5,16,18,21,26,27,44), and several studies also suggested that IL-1␤ was a key factor of early corneal neovascularization (CNV) (2,12,39,40). In suture-induced mouse CNV models, the vascular growth had been marked as the significantly upregulated expressions of both IL-1␣ and IL-1␤.…”