Single-cell analysis revealed the role of CD8+ effector T cells in preventing cardioprotective macrophage differentiation in the early phase of heart failure

Heart failure is a complex clinical syndrome characterized by insufficient cardiac function. It has been characterized that heart resident and infiltrated macrophages play important roles in the cardiac remodeling in response to cardiac pressure overload, however, role of T cells has not been well characterized. Here we show that CD8+T cell depletion resulted in the late stage heart protection, but induced cardioprotective hypertrophy at an early stage of heart failure caused by cardiac pressure overload. Single cell RNA sequencing analysis revealed that cardioprotective hypertrophy was characterized by an expression of mitochondrial genes and growth factor receptors genes. CD8+T cells regulated the conversion of cardiac-resident macrophages as well as infiltrated macrophages to cardioprotective macrophages which express growth factor genes including Areg, Osm and Csf1 at the early phase of cardiac pressure overload, which are essential for the myocardial adaptive response. Our results demonstrate a dynamic interplay between cardiac CD8+T cells and macrophages that is necessary for adaptation to cardiac stress, and they highlight the homeostatic functions of tissue macrophages. The hearts of WT mice or mice without Tcells were pressure over loaded, and cardiomyocytes were harvested two weeks later for single-cell RNA sequencing (scRNA-seq) analysis.