Exposing molecular interactions between miRNAs and proteins in atrial fibrillation: a two-dimensional omics approach

Introduction Atrial fibrillation (AF) is the most common heart rhythm disorder. It can lead to serious adverse outcomes such as thromboembolism and heart failure resulting to increased mortality. The use of omics such as proteomics and epigenomics may enable discovery of novel targets related to AF pathogenesis and help uncover the molecular pathways involved. Purpose To compare the expression of total proteome and miRNAs in atrial tissue samples from patients with AF and subjects with sinus rhythm (SR) and determine potential interactions connected to AF. Methods Right atrial appendages (RAA) were collected from patients undergoing open-heart surgery (study START). Twenty-eight tissue samples were included in proteomic analysis with AF (n=17) and SR (n= 11), and 27 samples were included in epigenomic analysis, AF (n=9) and SR (n= 18). RNA and proteins were extracted using a phenol-based method. Proteomic analysis was done with an LC-MS/MS system by a label- free- based quantitative approach (LFQ). MiRNAs were analyzed using the untargeted TaqMan OpenArray Human Advanced miRNA panel. Proteomic and epigenomic data were analyzed using bioinformatics tools. Results In AF compared to SR, 132 proteins were found to be overexpressed, while 80 proteins were underexpressed. From epigenetic analysis 10 miRNAs were found to be upregulated and 5 downregulated in AF compared to SR. Among them, 10 miRNAs were predicted to interact with 48 differentially expressed proteins identified in the proteomic analysis. A notable interaction was identified between ENC1 and miR-224-5p. ENC1 was underexpressed (abundance ratio AF/SR = 0.01, p = 0.021), while hsa-miR-224-5p was upregulated (RQ = 2.099, p = 0.024). miR-224-5p is involved in various biological processes, including the regulation of cell proliferation, migration, and apoptosis. ENC1is a member of the kelch-related family of actin-binding proteins and plays a role in the oxidative stress response. Conclusions A previously unreported potential interaction between ENC1 and miR-224-5p has been identified. Both miR-224-5p and ENC1 contribute to maintaining cellular homeostasis. Disruptions in these processes could lead to altered expression levels of miR-224-5p and ENC1, potentially affecting cellular function and stress response mechanisms. Further investigation is necessary to validate these miRNA-protein interactions and appreciate their potential contribution in AF pathogenesis.