Abstract
Purpose :
G-protein coupled receptor relaxin/insulin-like family peptide receptor 1 (RXFP1) signaling plays an important role in various physiologic as well as pathophysiologic processes, including ocular surface wound healing. In particular, binding of relaxin to RXFP1 promotes corneal wound healing through increased cell migration and modulation of extracellular matrix formation. Recently, C1q/tumor necrosis factor related proteins (CTRP) 1, 6 and 8 have been identified as novel interaction partners of RXFP1. We previously were able to detect CTRP1, CTRP6 and CTRP8 expression in cell lines and human tissue of the ocular surface and lacrimal apparatus. In this study, we aimed to investigate the effect of CTRP1, CTRP6 and CTRP8 on ocular surface wound closure and its dependence on the RXFP1 receptor pathway.
Methods :
In vitro ocular surface wound modeling was performed using a scratch assay. We analyzed the effects of recombinant CTRP1, CTRP6 and CTRP8 on cell proliferation and migration in human corneal and conjunctival epithelial cell lines. To determine the dependence on RXFP1 signaling, ligand binding to RXFP1 was inhibited by a specific anti RXFP1 antibody.
Results :
Treatment with either 100 ng/ml recombinant CTRP1, CTRP6 or CTRP8 resulted in a significantly increased surface defect closure rate in human corneal epithelial cells by a factor of 1.41 ± 0.08 (p < 0.001) for CTRP1, 1.20 ± 0.09 (p = 0.01) for CTRP6, and 1.24 ± 0.05 (p = 0.002) for CTRP8, but not in conjunctival epithelial cells. Inhibition of RXFP1 fully attenuated the effect of CTRP8 on the closure rate of surface defects in human corneal epithelial cells, whereas CTRP1 and CTRP6 effects were not completely suppressed.
Conclusions :
Our findings demonstrate a novel role for CTRP1, CTRP6 and CTRP8 in corneal wound closure in vitro by targeting the relaxin receptor RXFP1. This may provide future opportunities for drug discovery in the treatment of corneal wounds.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.