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.