Integrative analysis of miRNAs and proteins in plasma extracellular vesicles of patients with familial hypercholesterolemia.

Background And Aims: Familial Hypercholesterolemia (FH) is a monogenic disease that leads to early-onset atherosclerosis. Causative mutations in FH-related genes are found in 60-80 % of patients, while epigenetic factors may contribute to mutation-negative cases. This study analyzed miRNAs and proteins from plasma-derived extracellular vesicles (EVs) of FH patients to explore their contribution in FH diagnosis.

Methods: Clinical and laboratory data were obtained from 54 FH patients and 38 normolipidemic individuals. FH-related gene variants were identified using exon-targeted gene sequencing. Plasma EVs miRNome and proteome were analysed using small RNA sequencing and liquid chromatography/mass spectrometry.

Results: Thirteen FH patients carried LDLR deleterious variants (MD group), while 41 did not (non-MD group). Over 2000 miRNAs were detected in plasma EVs, with miR-122-5p higher in FH patients compared to controls, and miR-21-5p higher in the MD group than in the non-MD group (p < 0.05). Proteomic analysis identified 300 proteins with 18 out of 38 proteins more abundant in EVs than in total plasma. Eighteen EVs-derived proteins had differential abundance in FH patients compared to control group (p < 0.05). EV levels of miR-122-5p, miR-21-5p and 12 proteins were correlated with serum lipids (p < 0.05). The integrative analysis between dysregulated miRNAs (miR-122-5p and miR-21-5p) and altered proteins (APOD, APOF, MBL2 and MASP1) from EVs identified several common pathways involved in cholesterol metabolism.

Conclusion: Co-regulation of plasma EVs miR-122-5p, miR-21-5p, APOD, APOF, MBL2 and MASP1 and their correlation with serum lipids suggest their involvement in impaired cholesterol metabolism and may be useful as biomarkers of FH severity.