LIN28A blocks the EndMT process of high glucose‐induced HRMECs by stabilizing SIRT6 mRNA

ABSTRACT Background Diabetic retinopathy (DR) is a microvascular condition resulting from microangiopathy, causing gradual retinal damage and potential blindness. Endothelial–mesenchymal transition (EndMT) serves an important function in DR development. Exploring the molecular mechanism of EndMT in DR is needed. Methods Human retinal microvascular endothelial cells (HRMECs) were incubated with high glucose (HG) to induce an in vitro DR model. Lentivirus and small‐interfering RNAs were used to construct SIRT6 and LIN28A overexpression or knockdown in HRMECs, respectively. AMPK inhibitor, compound C, was used to block AMPK signaling in HRMECs. α‐SMA and PECAM1 levels were identified using immunofluorescence. CCK8 and transwell were used to detect cell viability and migration, respectively. The mRNA stability of SIRT6 was analyzed after HRMECs were exposed to actinomycin D. RNA immunoprecipitation was applied to verify the binding relationship between LIN28A and SIRT6 mRNA in HRMECs. Results In HG‐induced HRMECs, the cells undergo the EndMT process, and SIRT6 levels are downregulated. HG treatment reduced the level of p‐AMPK in HRMECs, and compound C reversed the inhibition of SIRT6 overexpression on EndMT in HG‐induced HRMECs. By binding to SIRT6 mRNA, LIN28A could enhance SIRT6 mRNA stability. Additionally, LIN28A overexpression inhibited EndMT in HG‐induced HRMECs, which was reversed by SIRT6 knockdown. Conclusion The stabilization of SIRT6 mRNA by LIN28A activated AMPK signaling, inhibiting the EndMT process in HRMECs caused by HG.