Abstract
Purpose: :
To study the effect of low power laser inactivation (LPLI) on the expression of miR-146a in RPE cells in association with cell proliferation and survival by targeting NF-kB.
Methods: :
A human retinal pigment epithelial cell line (hTERT-RPE1) was exposed to LPLI (670 nm, 2.88 J/cm2). The cell line was then characterized to determine the relative abundance of protein and mRNA levels of NF-kB and the up-regulation (expression) of miR-146a. Cell proliferation and survival assays were used to determine the effects of miR-146a targeted NF-kB.
Results: :
Following LPLI (670 nm, 2.88 J/cm2) expression kinetics for NFkB protein and mRNA levels were increased by 7 fold at 24 hours post exposure and 6 fold at 6 hours post exposure, respectively. Up-regulation of miR-146a was 10 fold at 2 hours post exposure. Compared to unexposed control cells the exposed cells had an increase of 25% in cell proliferation and survival 48 hours post exposure. Antagomir-mediated inhibition of miR-146a contributed to a decrease in expression of NFkB protein (24 hours post exposure) and mRNA (6 hours post exposure) by about 35% and 42%, respectively and the increase in cell proliferation and survival 48 hours post exposure was no longer visible.
Conclusions: :
Up-regulation of miR-146a induced by LPLI (670 nm, 2.88 J/cm2) targets the attenuation of NF-kB activity promoting cell proliferation and survival. This phenomenon represents a possible negative feedback loop affecting post transcriptional proteins. Therefore it may be possible to regulate RPE cell growth utilizing LPLI by affecting transcription controlled pathways.
Keywords: retinal culture • radiation damage: light/UV • cell survival