Effects of MicroRNA-499 On the Inflammatory Damage of Endothelial Cells During Coronary Artery Disease Via the Targeting of PDCD4 Through the NF-Κβ/TNF-α Signaling Pathway

Background/Aims: This study aimed to analyze the impact of microRNA-499 (miR-499) on the inflammatory damage of endothelial cells during coronary artery disease (CAD) via the targeting of PDCD4 through the NF-kB/ TNF-α signaling pathway. Methods: A total of 216 CAD patients (CAD group) and 90 healthy people (normal group) were enrolled in our study. Endothelial cells were collected and assigned into normal, OX-LDL, negative control (NC), miR-499 inhibitor, miR-499 mimic, PDCD4 siRNA, and miR-499 inhibitor + PDCD4 siRNA groups. The qRT-PCR and western blotting were performed to detect the mRNA and protein expression levels of PDCD4 and miR-499. The MTT assay was performed to determine cell viability, ELISA was performed to determine the expression levels of inflammatory factors, and flow cytometry assay to evaluate cell apoptosis. Results: Increased miR-499 expression and decreased PDCD4 expression in the plasma were observed in the CAD group compared with the normal group, demonstrating a negative correlation between miR-499 and PDCD4. Compared to the normal and miR-499 inhibitor groups, the survival rate of cells and PDCD4 expression were decreased; and the expressions of miR-499, IL-6, IL-8, IL-1β, TNF-α, NF-kB, VCAM-1, ICAM-1 and MCP-1 and the apoptosis rate were all elevated in the OX-LDL, NC, miR-499 mimic, PDCD4 siRNA and miR-499 inhibitor + PDCD4 siRNA groups. Compared to the OX-LDL, NC and miR-499 inhibitor + PDCD4 siRNA groups, PDCD4 expression and the survival rate of cells were increased; and the IL-6, IL-8, IL-1β, TNF-α, NF-κB, VCAM-1, ICAM-1 and MCP-1 expression levels and the apoptosis rate were all reduced in the miR-499 inhibitor group. In the PDCD4 siRNA group, PDCD4 expression and the survival rate of cells were lower, and the expression levels of IL-6, IL-8, IL-1β, TNF-α, NF-κB, VCAM-1, ICAM-1 and MCP-1 and the apoptosis rate were all higher compared with the miR-499 mimic group. In the miR-499 inhibitor + PDCD4 siRNA group, PDCD4 expression and the survival rate of cells were higher, and the expression levels of IL-6, IL-8, IL-1β, TNF-α, NF-κB, VCAM-1, ICAM-1, and MCP-1 and the apoptosis rate were all lower than those in the PDCD4 siRNA group. Conclusion: Down-regulated miR-499 expression increased PDCD4 expression and protected endothelial cells from inflammatory damage during CAD by inhibiting the NF-κB/TNF-α signaling pathway.