Abstract
Purpose :
Apolipoprotein A-1 (ApoA-1) has recently been identified as a retinoic acid binding protein and is upregulated in the choroids of chick eyes recovering from induced myopia (Summers JA, et al. IOVS 2016; ARVO E-Abstract, submitted). Therefore, we are highly interested in identifying the molecular mechanisms responsible for the regulation of choroidal ApoA-1 expression.
Methods :
Choroids were isolated from normal chick eyes and incubated at 37°C in N2 media containing fenofibric acid (100 – 500 µM), GW7647 (0.1 -1.0 µM) and all-trans retinoic acid (10 uM). Following incubation, choroids were snap frozen and total RNA was extracted, DNAase-treated, and used for the synthesis of cDNA with reverse transcriptase and random hexamers. ApoA1 expression was quantified from cDNA samples by Taqman real time PCR and normalized with the housekeeping gene, GAPDH. Cycle-threshold data was converted to relative gene expression using CFX-Manager (Bio-rad) and analyzed using Student’s t-tests and ANOVA.
Results :
Previous studies have suggested that PPAR-α agonists and retinoic acid can modulate ApoA-1 gene expression in a variety of tissues. Choroidal expression of ApoA1 was not significantly affected by treatment with either PPAR-α agonist, fenofibric acid or GW7647 (p >0.05). Retinoic acid (10uM) however, significantly upregulated choroidal ApoA-1 gene expression (↑ 743% p < 0.001).
Conclusions :
The specific upregulation of ApoA-1 by retinoic acid observed in the present study suggests the presence of a novel pathway for the regulation of retinoid transport and metabolism in the ocular choroid.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.