Inhibitory effects of miR-146a on retinal inflammation induced by high glucose in human retinal endothelial cells

Objective

To observe the effects of miR-146a on human retinal endothelial cell (HREC) under high glucose condition.

Methods

Total of 57 cases diagnosed as diabetic mellitus and 40 cases with diabetic retinopathy (DR) in Wuxi People’s Hospital Affiliated to Nanjing Medical University from October to December 2013.Forty-one healthy volunteers were enrolled and served as control group.The clinical data and venous blood samples of subjects were collected.HRECs were cultured in normal glucose (5.5 mmol/L) or high glucose medium (30 mmol/L). Real-time PCR was used to detect the expression of miR-146a.The cultured HRECs were transfected with miR-146a mimic, mimic negative control, inhibitor and inhibitor negative control by lipofectamine2000, respectively.The expression of miR-146a and intercellular cell adhesion molecule-1 (ICAM-1) mRNA was examined by real-time PCR and the expression of nuclear factor-кB (NF-кB) p65 and NF-кB p65^Ser536 was detected by Western blot assay.

Results

The relative expression of miR-146a mRNA in the diabetic mellitus group and DR group was 0.36±0.08 and 0.27±0.08, respectively, which were significantly lower than 1.00±0.16 in the control group (both at P<0.01). The expression of miR-146a mRNA was 0.37±0.11 in the high glucose group, which was lower than 1.00±0.18 in the normal control group (t=5.57, P<0.01). The relative expression of miR-146a mRNA in the miR-146a mimic group was 2 540.00±105.00, which was significantly higher than 61.00±17.90 in the miR-146a mimic control group; The relative expression of miR-146a mRNA in the miR-146a inhibitor group was 0.04±0.01, which was significantly lower than 0.88±0.04 in the miR-146a inhibitor control group (t=23.23, 17.12; both at P<0.01). The relative expression of ICAM-1 mRNA in the miR-146a mimic group was 0.35±0.12, which was significantly lower than 1.00±0.13 in the miR-146a mimic control group; The relative expression of ICAM-1 mRNA in the miR-146a inhibitor group was 2.74±0.48, which was significantly higher than 1.00±0.16 in the miR-146a inhibitor control group (t=3.58, 3.37; both at P<0.05). The relative expression of NF-кB p65^Ser536 in the miR-146a mimic group was 0.43±0.03, which was significantly lower than 1.07±0.09 in the miR-146a mimic control group (t=6.74, P<0.01). The relative expression of NF-кB p65^Ser536 in the miR-146a inhibitor group was 2.08±0.12, which was significantly higher than 1.00±0.01 in the miR-146a inhibitor control group (t=8.76; P<0.01).

Conclusions

miR-146a can reduce inflammation of HREC in high glucose condition through inhibiting ICAM-1 expression and NF-кB phosphorylation.