Involvement of the <scp>miR</scp>‐128‐3p/<scp>KDM3A</scp>/<scp>NLRP3</scp> Axis in High Glucose‐Induced Inflammatory Injury in Retinal Endothelial Cells

This study explores the regulatory mechanism of the miR-128-3p in diabetic retinopathy (DR)-associated inflammatory injury. A cellular model of DR was established by inducing immortalized human retinal endothelial cells (IM-HRECs) with high-glucose (HG). Cell viability was evaluated by CCK-8 assay, and the levels of TNF-α, IL-1β, and IL-10 were measured by ELISA. RT-qPCR was performed to determine miR-128-3p expression, and miR-128-3p mimics were transfected into cells to verify its regulatory role in DR-associated inflammatory injury. miR-128-3p was predicted by Starbase to bind to the 3' UTR of KDM3A, which was verified by dual-luciferase assay. The expressions of KDM3A and NLRP3 in cells were examined by Western blotting, and the enrichment of KDM3A and H3K9me2 on the NLRP3 promoter was measured by Ch-IP assay. The results revealed that HG treatment significantly reduced both IM-HREC viability and IL-10 levels, increased the levels of TNF-α and IL-1β, and downregulated the expression of miR-128-3p. Overexpression of miR-128-3p reduced inflammation in IM-HRECs induced by HG. The proposed mechanism involves targeting of the KDM3A 3' UTR by miR-128-3p, leading to reduced KDM3A expression, while KDM3A increased NLRP3 expression by reducing H3K9me2. In conclusion, upregulation of miR-128-3p increases the histone H3K9me2 level by inhibiting KDM3A expression, thereby reducing NLRP3 expression and suppressing DR inflammatory injury.