DNA-damaging Chemotherapy altered the Cardiac Pathogenesis by reshaping the Composition and Functionality of Cardiac Resident Macrophages (bulk RNA-Seq).

Cardiovascular comorbidities including heart failure and ischemic heart injury represent the most common causes of death among cancer survivors. Despite extensive investigation, we continue to have a poor understanding of how previous chemotherapy reagents exposure impact the heart. Here, we investigated the effect of chemotherapy reagent on the composition and function of the cardiac resident macrophages and found carboplatin selectively deplete the CCR2¬¬¬¬– cardiac macrophages by activating P53 signaling pathway and inducing necroptosis and apoptosis. Using Bulk-RNA-seq and lineage-tracing mice, we found CCR2– cardiac macrophages returned after Carboplatin-exposure primarily from monocytes recruitment and demonstrated a different transcriptomic profile. These reshaped CRMs attenuated heart remodeling upon hypertensive heart injury and ischemic-reperfusion injury while selective ablation of the reshaped CRMs abolished this mitigation phenotype. Using bulk-seq, single-cell RNA seq and lineage-tracing mice, we showed that the reshaped CRMs in carboplatin-exposed mice mitigated ventricle remodeling via elevated IFN-I signaling. Together, this study characterized how DNA-damaging chemotherapy reagent change the cardiac immune landscape and demonstrated a novel protective mechanism in adverse cardiac injury response that depends on the carboplatin-reshaped CRMs. These findings highlight the importance of type-I interferon signaling in the long-term effect of chemotherapy and provide promising pathway to retard cardiac pathogenesis. Overall design: To study the acute effect of carboplatin on the cardiac macrophages, we injected CCR2-GFP mice (Ccr2Gfp/+, JAX027619, half male half female, 8- to 12-week-old) with carboplatin (Sigma, C2538, 45 mg/kg, dissolved in PBS, i.p.) or equal volume of PBS. Three days later, the mice from Carbo group and PBS group were euthanized. The heart of these mice was dissected out and perfused with pre-cool HBSS before being digested with hyaluronidase, DNase I, and collagenase type IV on a shaker at 37 ?. The cardiac macrophages were sorted on the BD Melody FACS platform by gating on the CD45+CD11b+ Ly6G-CD64+Ly6Clo alive singlets. CCR2+ cardiac macrophage and CCR2- cardiac macrophage were differentiated by GFP expression and were sorted into separate tubes for RNA extraction and Bulk-RNA-sequencing. To study the long-term effects of carboplatin on the cardiac macrophages, we injected CCR2-GFP mice (Ccr2Gfp/+, JAX027619, half male half female, 8- to 12-week-old) with carboplatin (Sigma, C2538, 45 mg/kg, dissolved in PBS, i.p.) or equal volume of PBS for two weeks (twice a week). These experimental mice recovered for four weeks before being euthanized for cardiac macrophage isolation. The CCR2+ and CCR2- macrophages were differentiated by GFP expression and sorted into separate tubes for RNA extraction and Bulk-RNA-Sequencing.