MicroRNA changes in plasma associated with fibrous coronary plaque remodelling after PCSK9 inhibitor therapy in familial hypercholesterolemia with subclinical atherosclerosis

Patients with familial hypercholesterolemia (FH) exhibit lifelong elevated LDL-cholesterol levels and high risk of premature atherosclerotic cardiovascular disease despite lipid-lowering therapy. PCSK9 inhibitors reduce LDL-cholesterol and have shown to regress coronary atherosclerotic plaque burden in asymptomatic FH patients, but post-transcriptional miRNA mechanisms underlying these vascular effects remain unclear.

This study was aimed to identify differentially expressed miRNAs associated with changes ) in coronary plaque volume and composition as assessed by computed tomographic angiography (CTA) in FH patients treated with PCSK9 inhibitors added to high-intensity statins.

Seventy-seven FH patients with subclinical atherosclerosis from the SAFEHEART cohort underwent CTA at baseline and after 78 weeks of PCSK9 inhibitors (150 mg every 14 days) plus high-intensity statins. Plaque components (fibrous, fibro-fatty, calcified, and necrotic) were quantified. miRNA changes were analyzed by real-time PCR and bioinformatic tools (miTED, TAM, miRWalk, ShinyGO, Cytoscape, IPA).

An initial profiling of 375 miRNA was performed in a discovery subset (n=8), identifying 66 miRNAs consistently expressed in all subjects. Thirteen miRNAs with stable and quantifiable expression were selected for validation in the full cohort (n=77). Hierarchical clustering revealed two miRNA clusters [Cluster 1 (8 miRNAs) and Cluster 2 (5 miRNAs)] related to tissue remodelling processes (cell proliferation, innate immunity, and stem cell differentiation). The most relevant changes occurred in miRNAs miR-342-3p (immune-related source, Cluster 1) and miR-193a-5p (vascular-related source, Cluster 2). Changes in both miRNA positively correlated with the observed increase in the percentage of fibrous plaque at follow-up (P=0.026 and p=0.001, respectively). Moreover, miR-193a-5p changes were inversely correlated with reductions in fibro-fatty plaques (P=0.017). miR-342-3p changes were associated with PCSK9 inhibitor-induced lipid reductions, whereas miR-193a-5p changes appeared lipid-independent. Combined target gene predictions for the effects of the two miRNAs relate to FGF and PDGF signaling, including genes such as SOS1, PIK3CD, PPP2R1A, MAPK9, and RPS6KA5. Downregulation of SOS1, PIK3CD, MAPK9, and RPS6KA5, genes regulating inflammation, cell proliferation, and apoptosis, is linked to plaque stabilization.

FH patients treated with a PCSK9 inhibitor exhibited a differential miRNA signature. Predicted target genes for upregulated miR-320a-3p and miR-21-5p relate to cell functions involved in plaque remodelling and stabilization.