Single cell RNAseq profiling of Tbx1 function in adult post myocardial infarction hearts [scRNA-seq]

Post-myocardial infarction (Post-MI) heart failure is an unanswered clinical challenge. Current immunological intervention trials to reduce MI damage are unsatisfactory. Thus a thorough understanding of post-MI immune response is imperative. Tbx1, the major 22q11.2 deletion syndrome (22q11.2DS) disease gene, reactivated in cardiac lymphatic endothelial cells (LECs) to promote post-MI repair. Endothelial deletion of Tbx1 deteriorated post-MI cardiac function through a dual approach, impaired lymphangiogenesis and weakened immunosuppression. To characterize cell autonous function of Tbx1 in endothelial population and cell non-autonous effect in immune cells, we set to performed scRNA-seq on Ctrl (Tbx1flox/flox) and Tbx1cko (Fabp4-Cre;Tbx1flox/flox) hearts. The dataset is comprised of total 55,106 single cells transcriptomes. We identified eight principal non-myocyte types with their known markers, including CD31-expressing vascular endothelial cell (VEC), LEC, pericyte, as well as CD45-expressing monocyte/macrophage, dendritic cell (DC), neutrophil, T/innate lymphoid cell (ILC), and B cell. Interestingly, we found that the relative percentage of monocyte/macrophage population, which is most abundant among all immune cells, was significantly decreased in Tbx1cko hearts, whereas T/ILC population was increased. Taken together, single cell transcriptomic analyses suggest a potential cell non-autonomous effect that Tbx1 deficiency in endothelium may cause imbalance in immune response. Overall design: We set to performed scRNA-seq on enriched CD31+ endothelial cells and CD45+ leucocytes from Ctrl and Tbx1cko hearts. We collected samples at 4, 5, 6, and 7 dpMI, reasoning that the the most significant cellular and transcriptional distincts between Ctrl and Tbx1cko would occur during the initial 4-day window of Tbx1 reactivation.