Long non-coding ribonucleic acid ATP2B1-AS1 modulates endothelial permeability through regulating the miR-4729-IQGAP2 axis in diabetic retinopathy

Abstract

Aims/introduction: Mounting evidence shows that long non-coding RNAs (lncRNAs) are important to modulate the biological process of diabetic retinopathy (DR). We aimed to investigate the role of lncRNAs in DR and elucidate the exact mechanism.

Materials and methods: Real-time quantitative polymerase chain reaction was carried out to distinguish the lncRNA ATPase plasma membrane Ca²⁺ transporting 1 antisense RNA 1 (ATP2B1-AS1) expression in DR patients and HG-treated human retinal endothelial cells (HRECs). Dual-luciferase reporter system was used to verify that ATP2B1-AS1 could act as a microRNA (miR)-4729 sponge, and miR-4729 could bind to 3'UTR of IQ motif-containing GTPase-activating protein 2 (IQGAP2). Cell proliferation assay, wound healing migration assay, transwell assay, tube formation assay and immunofluorescence were used to investigate cell proliferation, migration and angiogenesis in HRECs.

Results: The present results showed that ATP2B1-AS1 was downregulated in DR patients and high-glucose-induced HRECs. In gain- and loss-of-function assays, ATP2B1-AS1 overexpression could significantly reduce cell proliferation, migration, angiogenesis and permeability induced by high glucose in vitro. Additionally, we carried out dual-luciferase reporter experiments to determine that ATP2B1-AS1 could act as a miR-4729 sponge. ATP2B1-AS1 overexpression could rescue miR-4729 mimics and short hairpin RNA-IQGAP2 induced cell proliferation, migration and angiogenesis in HRECs.

Conclusions: The present study showed that ATP2B1-AS1 acted as a miR-4729 sponge to regulate IQGAP2 reducing high-glucose-induced endothelial dysfunction in DR.

Keywords: ATP2B1-AS1; Diabetic retinopathy; miR-4729.

Figure 1

Identification of ATPase plasma membrane Ca²⁺ transporting 1 antisense ribonucleic acid 1 (ATP2B1‐AS1) in diabetic retinopathy (DR) and high‐glucose‐treated high‐glucose‐treated human retinal endothelial cells (HRECs). (a) The heatmap of the differentially expressed genes in low glucose (LG) and high glucose (HG). Upregulated genes and downregulated genes are shown in red and blue. (b) Volcano plots showing long non‐coding ribonucleic acids expression in the LG and HG groups. The red dots show the significant expressed genes. (c) Reverse transcription quantitative polymerase chain reaction was carried out to detect ATP2B1‐AS1 levels in 5 mmol/L or 25 mmol/L glucose treated HRECs. (d) Reverse transcription quantitative polymerase was carried out to distinguish the level of ATP2B1‐AS1 in blood samples obtained from DR patients (n = 30) and healthy individuals. All values were represented by the mean ± standard deviation. *P < 0.05, **P < 0.01, ***P < 0.001.

Figure 2

ATPase plasma membrane Ca²⁺ transporting 1 antisense ribonucleic acid 1 (ATP2B1‐AS1) prevents cell proliferation, migration, angiogenesis and permeability. (a) Reverse transcription quantitative polymerase chain reaction was made to measure the expression of ATP2B1‐AS1 after transfecting plasmid cloning deoxyribonucleic acid (pcDNA)‐long non‐coding ribonucleic acids (lncRNA) ATP2B1‐AS1 (pcDNA‐lnc) and (short hairpin RNA‐lncRNA ATP2B1‐AS1; shR‐lnc) into high‐glucose‐treated human retinal endothelial cells (HRECs). (b) The level of ATP2B1‐AS1 was detected by reverse transcription polymerase chain reaction after transfecting pcDNA‐lnc and shR‐lnc into HRECs by Cell Counting Kit‐8 assay. (c) Proliferation of HRECs was detected by Cell Counting Kit‐8 assay. (d, e) Migration ability was measured by wound healing migration assay and transwell assay. (f) Tube formation assay was used to distinguish angiogenesis ability in HRECs. (g) Cell junctional assembly formation of CDH5 staining. (h) Vascular permeability was detected by using evans blue injection. All values were represented by the mean ± standard deviation. *P < 0.05, **P < 0.01, ***P < 0.001.

Figure 3

ATPase plasma membrane Ca²⁺ transporting 1 antisense ribonucleic acid 1 (ATP2B1‐AS1) sponges microRNA (miR)‐4729. The microRNAs lists and scores on predicted by using the MicroRNA Target Prediction Database. (b) Predicted miR‐4729 binding sites in 3′UTR of ATP2B1‐AS1 and dual luciferase report assay in ATP2B1‐AS1‐wild type (WT) or ATP2B1‐AS1‐mutation (MUT) co‐transfected with miR negative control (NC) or miR‐4729 mimics. (c) Level of miR‐4729 in high‐glucose‐treated human retinal endothelial cells (HRECs) transfected with shR‐lnc or pcDNA‐lnc. (d) miR‐4729 expression in blood from diabetes retinopathy (DR) patients (n = 30) and non‐DR individuals. (e) Pearson's correlation analysis was used to check the relationship between ATP2B1‐AS1 and miR‐4729. All values were represented by the mean ± standard deviation. *P < 0.05, **P < 0.01, ***P < 0.001.

Figure 4

ATPase plasma membrane Ca²⁺ transporting 1 antisense ribonucleic acid 1 (ATP2B1‐AS1) reduced high glucose‐treated high‐glucose‐treated human retinal endothelial cells (HRECs) cell proliferation, migration, angiogenesis and permeability through regulating microRNA (miR)‐4729–IQ motif‐containing GTPase‐activating protein 2 (IQGAP2) axis. (a) Schematic indicating the miR‐4729 sites in IQGAP2 and dual luciferase assay in IQGAP2‐wild type (WT) or IQGAP2‐mutation (MUT) treated HRECs co‐transfected with miR‐NC or miR‐4729 mimics. (b) The protein IQGAP2 level was detected by WB after transfection. (c) HRECs proliferation was detected by Cell Counting Kit‐8 assay after transfection. (d, e) Migration ability was measured by wound healing migration assay and transwell assay after transfection. (f) Tube formation assay was used to detect the ability of angiogenesis in HRECs after transfection. (g) Cell junctional assembly formation of VE‐cadherin staining after transfection. All values were represented by the mean ± standard deviation. *P < 0.05, **P < 0.01, ***P < 0.001.

Figure 5

Graphic model of long non‐coding ribonucleic acids (lncRNA) ATPase plasma membrane Ca²⁺ transporting 1 antisense ribonucleic acid 1 (ATP2B1‐AS1) modulates endothelial permeability. ATP2B1‐AS1 acts as a microRNA (miR)‐4729 sponge to regulate IQ motif‐containing GTPase‐activating protein 2 (IQGAP2) reduce high‐glucose‐induced endothelial dysfunction in diabetic retinopathy. Decreased ATP2B1‐AS1 significantly reduced cell proliferation, migration, angiogenesis and permeability through the miR‐4729–IQGAP2 axis in response to hyperglycemia.