CircSamd4: A novel biomarker for predicting vascular calcification.

BACKGROUND: Vascular calcification (VC) is usually associated with cardiovascular diseases (CVDs), which are one of the main causes of mortality in the world. This study aimed to analyze the expression of circular RNAs (circRNAs) in patients with VC and to evaluate biomarkers for the diagnosis of VC. METHODS: Calcified human aortic endothelial cells (HAECs) and the calcification in mouse aorta were detected by qRT-PCR. Subsequently, this was verified in the plasma of patients with coronary artery calcification (CAC). The plasma of 40 patients in the control group and 31 patients in the calcified group were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR) to detect the level of circSamd4a in the blood. The diagnostic value was evaluated by logistic regression analysis and the working characteristics of subjects. RESULTS: In the HAECs, the qRT-PCR showed a significant decrease in the level of circSamd4a expression in the calcification group compared to the control group (p < 0.05). The calcified mouse aorta showed the same trend for circSamd4a expression, wherein the difference was statistically significant (p < 0.05); the expression of circSamd4a was significantly downregulated in the plasma of patients with VC (p < 0.01). The receiver operating characteristic (ROC) curves of circSamd4a in patients with VC and control group showed that the area under the curve (AUC) was 0.81 (95% CI: 0.707-0.913; p < 0.001). CONCLUSION: CircSamd4a showed a stable downward trend in different specimens, and had significant advantages as a biomarker for diagnosis of VC.

[Knockdown of PCSK9 inhibits endothelial-to-mesenchymal transition of human aortic endothelial cells].

Objective To investigate the protective effect of proprotein convertase subtilisin/kexin type 9 (PCSK9) knockdown on endothelial-to-mesenchymal transition (EndoMT) induced by ß glycerophosphate, dexamethasone, and L-ascorbic acid in human aortic endothelial cells (HAECs). Methods EndoMT model was established by inducing HAECs with (0, 10, 30, 50) mmol/L of ß glycerophosphate combined with 100 nmol/L of dexamethasone and 50 µg/mL of L-ascorbic acid. HAECs were transfected with specific small interfering RNA of PCSK9 (si-PCSK9), and the mRNA and protein expression levels of PCSK9 in HAECs were detected by real-time quantitative PCR and Western blotting. HAECs were randomized into blank group, EndoMT group, EndoMT group transfected with negative control small interfering RNA (si-NC), and EndoMT group transfected with si-PCSK9. The mRNA levels of α-smooth muscle actin (α-SMA), fibroblast-specific protein 1 (FSP1), and vascular endothelial cadherin (VE-cadherin) were detected by real-time quantitative PCR, the protein levels of α-SMA and VE-cadherin were detected by Western blotting, and the expression of α-SMA was detected by immunofluorescence staining. Results 30 mmol/L of ß glycerophosphate had the best effect in inducing EndoMT, and the expression of PCSK9 mRNA and protein was up-regulated when EndoMT occurred. After PCSK9 knockdown, the expressions of α-SMA and FSP1 were down-regulated, while the expression of VE cadherin was up-regulated. Conclusion Knockdown of PCSK9 inhibits the EndoMT of HAECs.