Abstract
Background Circular RNAs (circRNAs) have been reported to be involved in the regulation of retinal pigment epithelial (RPE) cell injury and are closely related to the development of diabetic retinopathy (DR). More research is needed to confirm the role and mechanism of circ-ADAM9 in DR progression. Methods High glucose (HG)-induced RPE cells (ARPE-19) were used to mimic the hyperglycemia condition. The expression of circ-ADAM9, microRNA (miR)-338-3p, and coactivator-associated arginine methyltransferase 1 (CARM1) was measured using quantitative real-time PCR. Cell proliferation and apoptosis were determined using MTT assay, EdU assay, and flow cytometry. The protein expression of apoptosis markers and CARM1 was examined by the western blot analysis. Also, MDA level and SOD activity were determined to assess cell oxidative stress. In addition, the interaction between miR-338-3p and circ-ADAM9 or CARM1 was confirmed by dual-luciferase reporter assay and RIP assay. Results The expression of circ-ADAM9 was upregulated in DR patients and HG-induced ARPE-19 cells. Silenced circ-ADAM9 could promote proliferation and inhibit inflammation, apoptosis, and oxidative stress in HG-induced ARPE9 cells. In terms of mechanism, circ-ADAM9 could sponge miR-338-3p to upregulate CARM1. The inhibitory effect of circ-ADAM9 knockdown on HG-induced ARPE9 cell injury could be reversed by an miR-338-3p inhibitor. As a target of miR-338-3p, CARM1 knockdown could alleviate HG-induced ARPE9 cells' injury, and its overexpression also could reverse the negatively regulation of miR-338-3p on HG-induced ARPE9 cell injury. Conclusion Circ-ADAM9 contributed to HG-induced ARPE9 cell injury by regulating miR-338-3p/CARM1 axis, which provided effective targets for DR treatment.
Highlights
Diabetic retinopathy (DR) is the most important manifestation of diabetic microangiopathy, which is one of the serious and syndromic manifestations of diabetes [1, 2]. e main reason is that the retinal tissues and vascular microcirculation of diabetic retinopathy (DR) patients have changed, resulting in the damage of eye nutrition and visual function [3, 4]. e dysfunction of the blood-retinal barrier (BRB) induced by hyperglycemia is considered to be one of the earliest changes in DR [5, 6]
A recent study showed that circ-ADAM9 promoted High glucose (HG)-induced apoptosis, inflammation, and oxidative stress in retinal pigment epithelial (RPE) cells, suggesting that circ-ADAM9 might contribute to DR progression [19]
In HG-induced ARPE-19 cells cotransfected with miR-338-3p mimic and pcDNA coactivator-associated arginine methyltransferase 1 (CARM1) overexpression vector, we found that the decreasing effect of miR-338-3p mimic on miR-338-3p expression could be abolished by pcDNA CARM1 overexpression vector (Figure 7(b)). e inhibition effect of miR-338-3p on the concentrations of IL-6 and TNFα and the promotion effect on the viability and the EdUpositive cell rate could be eliminated by overexpressing CARM1 in HG-induced ARPE-19 cells (Figures 7(c)–7(e))
Summary
Circular RNAs (circRNAs) have been reported to be involved in the regulation of retinal pigment epithelial (RPE) cell injury and are closely related to the development of diabetic retinopathy (DR). Cell proliferation and apoptosis were determined using MTT assay, EdU assay, and flow cytometry. The interaction between miR-338-3p and circ-ADAM9 or CARM1 was confirmed by dual-luciferase reporter assay and RIP assay. E expression of circ-ADAM9 was upregulated in DR patients and HG-induced ARPE-19 cells. Silenced circ-ADAM9 could promote proliferation and inhibit inflammation, apoptosis, and oxidative stress in HG-induced ARPE9 cells. E inhibitory effect of circ-ADAM9 knockdown on HG-induced ARPE9 cell injury could be reversed by an miR-338-3p inhibitor. As a target of miR-338-3p, CARM1 knockdown could alleviate HG-induced ARPE9 cells’ injury, and its overexpression could reverse the negatively regulation of miR-338-3p on HGinduced ARPE9 cell injury. Circ-ADAM9 contributed to HG-induced ARPE9 cell injury by regulating miR-338-3p/ CARM1 axis, which provided effective targets for DR treatment
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