Single-cell RNA-sequencing Unravels Heterogeneity of Cardiomyocytes and Signaling Pathways in Pressure Overload

Background This study aimed to unravel the heterogeneity of cardiomyocytes and probed out hub genes and hub pathways for cardiac hypertrophy based on transverse aortic constriction (TAC) mouse models using single-cell RNA sequencing (scRNA-seq). Methods scRNA-seq data of TAC mouse models were retrieved from the GSE95140 dataset. After filtering, cell clusters were detected using scRNA-seq data, followed by identification of differentially expressed genes (DEGs). Then, functional enrichment analysis of DEGs was presented. GSVA scores of hub pathways were calculated. After that, hub genes were detected by protein-protein interaction (PPI) network and expression association analysis. Cell subtypes were clustered using UMAP and the expression patterns of hub genes across different cell subtypes and different stages of cardiac hypertrophy were visualized. Finally, hub genes and hub pathways were verified using the GSE76 and GSE36074 datasets. Results Following data filtering and normalization, 3408 DEGs were identified between TAC and sham operation. As shown functional enrichment analysis, hub pathways were identified including cardiac hypertrophy, ion transport, myocardial remodeling, apoptosis, HIF pathway and metabolise. Eight hub genes (Vldlr, Ugp2, Tgm2, Pygm, Flnc, Ctsd, Clu and Atp1b1) with the highest degree in the PPI network and the strongest correlation with GSVA calculated score of hub pathways were identified for cardiac hypertrophy. Six cell subtypes were clustered, composed of fibroblast, CM-A, CM-V, trabecular CM and endothelial cell. There was a distinct heterogeneity in the expression patterns of hub genes and the GSVA scores of hub pathways across different cell clusters and different stages of cardiac hypertrophy. The hub genes and hub pathways were externally verified by the two independent datasets. Conclusion Our findings identified hub genes and hub pathways for cardiac hypertrophy, which had a distinct heterogeneity across different cell clusters and different stages of cardiac hypertrophy.