Exenatide regulates inflammation and the production of reactive oxygen species via inhibition of S1PR2 synthesis.

BACKGROUND

Microvascular dysfunction is one of the most serious complications of diabetic retinopathy (DR). As a novel treatment drug for type 2 diabetes, exenatide possesses protective properties against retinal neurodegeneration. Sphingosine-1-phosphate receptor 2 (S1PR2) could regulate blood glucose in diabetes, and inhibition of S1PR2 is involved in the treatment of diabetes. However, the mechanism of exenatide in human retinal vascular endothelial cells (hRVECs) has not been fully defined.

OBJECTIVES

We tested the hypothesis that S1PR2 plays a vital role in high glucose (HG)-induced hRVECs, and that exenatide could ameliorate HG-induced hRVEC injury by regulating S1PR2 production.

MATERIAL AND METHODS

The hRVECs underwent HG-stimulation. Quantitative real-time polymerase chain reaction (RT-qPCR) and western blot were performed to examine the expression of S1PR2. Oxidative stress levels, inflammatory markers and cell apoptosis were detected using reactive oxygen species (ROS) staining, enzyme-linked immunosorbent assay (ELISA) kits and TUNEL staining.

RESULTS

High glucose increased the level of S1PR2 in hRVECs and reduced the expression of glucagon-like peptide-1 receptor (GLP1R) compared to the control group. Exenatide decreased the level of S1PR2 induced by HG. Sphingosine-1 blocked the effects of exenatide, alleviating the ROS and cell apoptosis induced by HG. JTE-013 treatment protected hRVECs from injury by HG. The inhibitory effects of exenatide on S1PR2 expression lessened HG-induced hRVEC injury.

CONCLUSIONS

The results demonstrate a possible mechanism of exenatide mediated inhibition of S1PR2 synthesis, and support S1PR2 as a novel target for treating DR.