Single-Nucleus Transcriptomics Reveal Cell Type-Specific Diversification in Left Ventricle in Mice Undergoing Arteriovenous Fistula Creation with Cardiac-Specific Overexpression of PDE5A

Background: PDE5A, an enzyme that hydrolyses cyclic guanosine phosphate (cGMP), has been implicated in various cardiovascular conditions. We have observed an increase in protein levels of cardiac PDE5A following arteriovenous fistula (AVF) creation in left ventricle (LV) (Fig.1-A). AVF creation has been associated with increased cardiac output and dilation of LV leading to adverse cardiac remodeling (Fig.1-B). We performed single nuclei RNA-seq to understand the cellular transcriptional profiles and pathway changes after AVF creation and the role of PDE5A in LV remodeling. Methods: AVF’s were created in cardiomyocyte-specific overexpression PDE5A transgenic mice (homozygous, HO) and littermate controls (WT). LVs were collected at day 7. Single nuclei RNA-seq was performed to identify gene signatures in WT (n=5), WT-AVF (n=4), HO (n=5), and HO-AVF (n=4) groups. Integration of Single Nuclei data (10X Chromium) was done using Seurat v.4 package. Results: We observed 19 different clusters, including 9 subtypes of cardiomyocytes (CM). Two CM clusters were not present in AVF group (Fig.1-C). There was a significant increase in endothelial cell count following AVF creation (p=3.2e-3). Notable gene expression changes include a downregulation in genes related to oxidative phosphorylation and ATP production (p=3.2e-18), an upregulation in genes linked to cardiomyocyte death and oxidative stress pathways (p=5.65e-310), downregulation in genes essential for sarcomere assembly and myofibrillogenesis (p=1.22e-190), and downregulation in genes essential for autophagy (p=1.153e-38), cytokines and inflammatory response (p=1.16e-99). Conclusion: Our snRNA-seq data indicates that AVF creation and PDE5A expression in cardiomyocytes contribute to cardiac impairment pathways and adverse remodeling. Funding: NIDDK Support