ABSTRACT
BACKGROUND: Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes. The present study aimed to identify a possible connection between gene polymorphisms and the risk of developing DR. MATERIALS AND METHODS: A total of 319 patients with type 2 diabetes mellitus (T2DM) were selected. All patients underwent a complete eye examination. Based on this, the patients with T2DM were divided into two subgroups: 175 patients with retinopathy (DR) and 144 patients without retinopathy (NDR). We calculated the genotype frequencies of case and control subjects using the chi-squares test. The odds ratio (OR) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression adjusted for age and sex. RESULTS: The finding by analysis is that the mean of duration of diabetes, total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), glomerular filtration rate and C-peptide were significantly different between DR and NDR. We found significant differences in cystatin-C concentrations with LEKR1-CCNL1 rs13064954 and NOS3 rs3918227 of different genotypes. Significant differences in serum TG levels were seen among the three genotypes of MTHFR rs1537516. Subjects carried the T allele of IGSF21-KLHDC7A rs3007729 had higher serum LDL concentrations (p = 0.015). In the allele model, LEKR1-CCNL1 rs13064954 decreased the risk of DR (OR =0.57, 95% CI = 0.34-0.96, p = 0.032). Under the dominant model, the IGSF21-KLHDC7A rs3007729 CT-TT genotype increased the risk of DR (OR =1.84, 95% CI = 1.14-2.99, p = 0.013). CONCLUSIONS: Our results suggest that LEKR1-CCNL1 and IGSF21-KLHDC7A influence the development of DR.
Subject(s)
Carrier Proteins/genetics , Cyclins/genetics , Diabetes Mellitus, Type 2/genetics , Diabetic Retinopathy/genetics , Genetic Predisposition to Disease/genetics , Membrane Proteins/genetics , Polymorphism, Single Nucleotide , Proteins/genetics , Ubiquitin-Protein Ligases/genetics , Adult , Aged , Asian People/genetics , China , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/ethnology , Diabetic Retinopathy/ethnology , Diabetic Retinopathy/etiology , Female , Gene Frequency , Genetic Predisposition to Disease/ethnology , Genotype , Humans , Lipids/blood , Male , Middle AgedABSTRACT
Hyperglycemia or high-glucose (HG)-induced apoptosis in human retinal pigment epithelial (RPE) cells is a characteristic process in diabetic retinopathy. In our study, we examined whether microRNA-29 (miR-29) may regulate HG-induced RPE cell apoptosis. Human RPE cell line, ARPE-19 cells, was treated with various high concentration of glucose in vitro. HG-induced RPE cell apoptosis was examined by terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay and miR-29 gene expression by quantitative RT-PCR (qRT-PCR). miR-29 was then downregulated in RPE cells, and its effect on HG-induced apoptosis was examined by TUNEL assay and western blot assay on caspase-7 protein. Association of miR-29 on its downstream target, PTEN, in HG-induced RPE cell apoptosis was evaluated by dual-luciferase assay and qRT-PCR. PTEN was silenced in RPE cells. The effects of PTEN downregulation on miR-29-mediated HG-induced RPE cell apoptosis were also examined by TUNEL and western blot assays. HG induced significant apoptosis in RPE cells in a dose-dependent manner. miR-29 was upregulated by HG in RPE cells. miR-29 downregulation protected HG-induced apoptosis and reduced the production of caspase-7 protein in RPE cells. PTEN was shown to be directly downregulated by HG and then upregulated by miR-29 downregulation in RPE cells. Small interfering RNA (siRNA)-mediated PTEN downregulation reversed the protective effect of miR-29 downregulation on HG-induced RPE cell apoptosis. This study demonstrates that miR-29, through inverse association of PTEN, plays an important role in the process of HG-induced apoptosis in RPE cells.
