DNA-damaging Chemotherapy altered the Cardiac Pathogenesis by reshaping the Composition and Functionality of Cardiac Resident Macrophages (scRNA-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: We collected hearts from 20 adult mice that were randomly grouped into 4 groups, PBS+Sham, CBP+ Sham, CBP +AngII/PE, and PBS+AngII/PE (each group has 5 mice of mixed gender). Mice were injected with Carboplatin (45 mg/kg, i.p., twice a week) or equal volume of PBS for two weeks. Then, all the mice underwent 4-week recovery. Next, we implanted osmotic minipump subcutaneously to each mouse. The minipump will either infuse Angiotensin II (1.5mg/kg/d) and PE (50mg/kg/d), or Saline (Sham group) for 7 days. Seven days after the minipump implantation, the CD64+ cardiac mononuclear phagocytes (CD45+CD11b+Ly6G–Ly6Clo) were sorted through FACS. Ten thousand cells from each group were pooled to make Single-cell barcoded cDNA libraries using 10X Genomics 3'v1kit following manufacturer's manual. GTAC core of WUSM conducted the quality control, sequencing, and alignment through cellRanger. Further analysis was performed using R studio (Seurat, DEseq2, ggplot2). The obtained single-cell RNA sequencing data contain 21681 features across 38066 samples. After being filtered as mitochondrial gene proportion(prompt) < 10.0%, nCounts of RNA<30000, and nFeature RNA counts< 7000 & >500, 20290 features across 17438 samples remained. We utilized graph-based clustering and UMAP (Uniform Manifold Approximation and Projection) visualization of the combined four groups (Dim=1:80, resolution=0.6, normalized by SCTransform). According to the feature genes of each cluster, the contamination from cardiomyocytes, endothelial cells, fibroblasts, lymphocytes were found and removed together with two junk clusters. The proliferating cells, monocytes, and mono-phagocytes including Dendritic cells and macrophages are kept for further analysis.