Evaluation of MicroRNA-200B polymorphisms association with sight-threatening diabetic retinopathy
Niloofar Zal1 , Fatemeh Suri1 *, Afrooz Moghadasi1 , Hamid Ahmadieh1 , Sare Safi2 , Maryam Eslami3 , Sahba Fekri4 , Majd Hejazi4
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Ophthalmic Epidemiology Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
- Applied Biotechnology Research Center, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
- Ophthalmic Research Center, Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Abstract: Diabetic retinopathy (DR) is a common sight threatening microvascular complication of diabetes mellitus (DM). The most important identified factor in pathogenesis of proliferative DR (PDR) is vascular endothelial growth factor (VEGF). The identification of increased intraocular VEGF in PDR has led to an encouraging outlook in the treatment of neovascularisation in patients with PDR via anti-VEGF therapies. miRNA-200b is a small non-coding RNA considered to affect on the development of DR by targeting and alleviating VEGF gene function. Assosiation of two genetic variants in MicroRNA-146A and MicroRNA-126 genes, both targeting VEGF, with sight-threatening DR (STDR) have been reported in previous studies. For the first time, association of MIR-200B gene polymorphisms with STDR was evaluated in this study.
Methods: Blood samples were collected from 141 diabeties patients including 77 cases with STDR and 64 controls. Genomic DNA was extracted from peripheral blood leukocytes using salting out protocol. The pri-miR-200B encoding gene obtained from the DNAs of all participants was amplified using polymerase chain reaction and subsequently sequenced by the Sanger method. The sequences were compared to reference sequence in order to identify sequence variations. The potential effects of a single variation observed on RNA structure was predicted using mFold, RNA Fold and Kine Fold softwares.
Results: Two genetic variations including g.1167277C> T and g1167183G> A (NC_000001.11; GRCH38.p12) were identified, both with more frequency in the case group. However, statistical analysis of the data did not show a significant difference between the control and case groups (P> 0.05). Bioinformatics analysis indicates the effect of both variants on the stability and hairpin structures of the predicted miRNA secondary structure.
Conclusion: The identified genetic variants may alter the function of miRNA-200b. Both variants were observed in the case group with higher frequency than the control group. Failure to obtain a significant p-value may be due to the limited sample size and complication of classifications of the diabetic patients because of the multi-factorial status of the disease. Increasing awareness of the genes involved in the pathogenesis of DR will lead to future treatment strategies.
