Purchase this article with an account.
Qi Wang, Svetlana N. Bozack, Matthew S. Faber, Walter J. Esselman, Julia V. Busik; Regulation Of The Inflammatory And Lipid Metabolic Genes By Rhythmic Expression Of Mir-146a And Mir-200b In Diabetic Retina. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4335.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Recent studies by others and us revealed that circadian clock is an important player in the pathogenesis of diabetes and diabetic complications. We have previously demonstrated that diabetic retinopathy (DR) is associated with depressed peripheral clock. Furthermore, the circadian rhythmicity of microRNA (miR) expression has been recently shown to regulate cell behavior and gene expression. miR-146a and miR-200b play an important role in the regulation of inflammation and angiogenesis. Previous studies on microRNA expression profiling demonstrated the suppression of miR-146a and miR-200b in diabetic retina. The purpose of this study is to investigate the role of miR-146a and miR-200b circadian expression pattern in regulation of major inflammatory genes and lipid metabolic genes in human retinal cell types known to be affected by diabetes, namely human retinal pigment epithelial (HRPE), human Muller cells (HMC) and human retinal vascular endothelial cells (HREC).
The HRPE and HMC from control donors cultured under normal and elevated glucose conditions, and the HREC from diabetic (n=5) and control donors (n=5) were synchronized with 100 nM dexamethasone and harvested for RNA analysis every three hrs for a 24 hr period. The expression levels of miR-146a, miR-200b, inflammatory genes and lipid metabolic genes were examined by quantitative real-time PCR. Mimics or inhibitors for miR-200b and miR-146a were transfected into HREC, respectively. Cells were lysed for RNA extraction 48 hours after transfection.
miR-146a and miR-200b showed circadian patterns in HRPE, HMC and HREC, and the circadian expression of both miR-146a and miR-200b was significantly affected by high glucose treatment or diabetes in these cells, respectively. The circadian rhythm was also observed in the expression of inflammatory genes (IL-1β, IL-1R1, VEGF, TGF-β and ICAM-1) in HRPE, HMC and HREC, and lipid metabolic genes (PPARγ, SREBP-1c, ELOVL4 and ELOVL2) in HREC. Among these genes, the circadian expression of ICAM-1, SREBP-1c, ELOVL4 and ELOVL2 was significantly increased by high glucose treatment or diabetes. Furthermore, transfection studies of miR-146a mimic or inhibitor showed that miR-146a was able to regulate the expression of ICAM-1 andPPARγ.
Our results demonstrate that dysregulation of miR circadian expression in diabetic retina leads to changes in inflammatory genes and lipid metabolic genes with potential implications for the development of diabetic retinopathy.
This PDF is available to Subscribers Only