miR-146b-5p serves as a novel biomarker for acute myocardial infarction and is involved in regulating oxidized low-density lipoprotein-induced endothelial injury through targeting PRKAR2A

Figures

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  Fig. 1. The miR-146b-5p expression and its association with AMI. a Upregulated miR-146b-5p expression in AMI subjects; (b) ROC curve identified miR-146b-5p diagnostic potential in AMI; (c-f) Upregulation of miR-146b-5p was correlated with hs-CRP(c), CK-MB (d), cTnI (e), and LVEF (f); (g) AMI subjects with advanced Killip grade (III-IV) showed higher miR-146b-5p expression; (h) K-M survival analysis indicated higher miR-146b-5p expression was associated with poor prognosis in AMI subjects. ***p < 0.001

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  Fig. 2. The miR-146b-5p expression in ox-LDL-induced HCAECs and its effect on cell proliferation and apoptosis. a Upregulated miR-146b-5p expression in ox-LDL-induced HCAECs was suppressed by miR-146b-5p knockdown; (b-d) MiR-146b-5p knockdown promoted HCAEC proliferation (b), decreased HCAEC apoptosis (c), and suppressed the caspase-3 activity (d) in ox-LDL-induced HCAECs. ns: no significance, **p < 0.01, ***p < 0.001

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  Fig. 3. The effect of miR-146b-5p on ox-LDL-induced HCAEC inflammation, oxidative stress, and levels of endothelial dysfunction markers. a-b miR-146b-5p knockdown attenuated ox-LDL-induced increases in IL-1β (a) and TNF-α (b) levels in HCAECs; (c-d) Knockdown of miR-146b-5p reduced MDA production (c) and enhanced SOD activity (d) in ox-LDL-induced HCAECs; (e-f) MiR-146b-5p knockdown decreased the expression of ET-1 (e) and vWF (f) in ox-LDL-induced HCAECs. ns: no significance, **p < 0.01, ***p < 0.001

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  Fig. 4. Bioinformatics analysis on miR-146b-5p downstream targets. a Venn diagram of predicted target genes from miRDB and Starbase, with 164 shared genes. b KEGG pathway enrichment analysis. c-e GO enrichment analysis for cellular component (c), molecular function (d), and biological process (e)

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  Fig. 5. Interaction between miR-146b-5p and PRKAR2A. a Binding sites of miR-146b-5p on PRKAR2A; (b) Negative correlation between miR-146b-5p and PRKAR2A expression in AMI; (c-d) Dual-luciferase reporter assays confirmed direct regulatory interaction between miR-146b-5p and PRKAR2A; (e) Downregulation of PRKAR2A in ox-LDL-induced HCAECs was upregulated by miR-146b-5p knockdown, which was further attenuated by PRKAR2A suppression; (f) Protein levels of PRKAR2A in ox-LDL-induced HCAECs was downregulated and could be upregulated by miR-146b-5p knockdown, which was further reversed by PRKAR2A silencing. ns: no significance, **p < 0.01, ***p < 0.001

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  Fig. 6. PRKAR2A suppression reversed the protective effect of miR-146b-5p suppression in ox-LDL-induced HCAEC injury. a-i PRKAR2A knockdown counteracted the beneficial effects of miR-146b-5p suppression by inhibiting cell proliferation (a), promoting apoptosis (b), and (c) enhancing caspase-3 activity (c), while also exacerbating inflammation through increased IL-1β (d) and TNF-α (e) levels, intensifying oxidative stress via elevated MDA levels (f) and reduced SOD activity (g), and suppressing endothelial dysfunction markers as shown by decreased levels of ET-1 (h) and vWF (i). ns: no significance, **p < 0.01, ***p < 0.001