Fig. 5.

Differential protein expression between right and left atrium captures physiology and disease status. A, Volcano plot analysis of protein expression in right- versus left atria in seven individuals depicts significance of differential expression for each measured protein (points). Mean fold-change of protein expression between RA and LA (left: higher in LA, right: higher in RA) is plotted against statistical significance of the differential expression (Student's t test p value). Proteins with strong differential expression at high statistical significance populate the upper corners of the graph. The analysis identified 109 proteins statistically significantly higher expressed in either LA (42 proteins, green) or RA (67 proteins, blue) at 5% false discovery rate (black line) FDR. Gene names are listed for all significant proteins. B and C, STRING-based protein-protein interaction networks for collagens (B) and natriuretic peptide system components (C) identified in our data depict protein abundance (node size) and differential expression between chambers (node color: green - higher in LA, blue - higher in RA). The networks highlight higher collagen abundance in LA (B) and higher abundance of natriuretic peptide signaling pathway in RA (C). The table shows PheWAS associations and corresponding p values for genes in the natriuretic peptide signaling network from the UK Biobank PheWeb, highlighting involvement in hypertension and heart block. Abbreviations: LA: left atrium; RA: right atrirum, iBAQ: intensity-based absolute quantification. Data based on biopsy measurements of seven individuals: 7 RA biopsies, 6 LA biopsies, 7 LV biopsies are underlying this analysis.