Abstract
Purpose :
We previously demonstrated that growth hormone-releasing hormone (GHRH) receptor is expressed in rat adult retina and participated in uveitis and retinoblastoma development. Here we aimed to investigate the GHRH receptor signaling in rat retinal development and retinal progenitor cell differentiation.
Methods :
GHRH receptor expression was determined in the retinas of Sprague-Dawley rats (embryonic day (E) 10 to adult) by the immunofluorescence analysis. Retinal progenitor cells from E18 and post-natal day (PN) 1 rat retinas were isolated, purified and cultured in DMEM/F-12 medium with N2 supplement, basic fibroblast growth factor and epidermal growth factor on the non-adherent culture dishes for 3 days, followed by the treatment of retinal differentiation medium (DMEM/F-12 medium with B27 supplement) with the GHRH agonist and antagonist for 7 days. Retinal cell differentiation was evaluated by the immunofluorescence analysis of specific retinal cell markers (Chx10 for retinal progenitor cells, TuJI for retinal ganglion cells, rhodopsin for photoreceptors and GFAP for Müller glia).
Results :
In rat retina, the GHRH receptor was expressed in the retinal ganglion cell layer from E14 to adult. During retinal progenitor cell differentiation, the GHRH receptor agonist and antagonist both upregulated the expression of GHRH receptor in the E18 and PN1 induced retinal progenitor cells, compared to the vehicle control group. Upon GHRH receptor antagonist treatment, the expression of Chx10 in the induced retinal progenitor cells was decreased, whereas the expressions of GFAP and rhodopsin were increased, compared to the vehicle control groups. Upon GHRH receptor agonist treatment, Chx10 and rhodopsin expressions were increased in the induced retinal progenitor cells, whereas the expression of GFAP was decreased. There was no significant difference in TuJI expression among the three treatment groups.
Conclusions :
GHRH receptor is expressed in retinal ganglion cell layer along the rat retinal development. GHRH receptor signaling could be involved in retinal progenitor maintenance as well as photoreceptor and Müller glia differentiation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.