Clin Res Cardiol (2023). https://doi.org/10.1007/s00392-023-02180-w

Macrophage-derived PDGFs drive fibrosis in human HFpEF

J. Leberzammer1, A.-P. Das2, M. Bendel2, D. John2, V. Larcher2, B. Schumacher2, M. Merten2, A. M. Zeiher3, D. Leistner1, J. Krishnan2, E. Nagel4, S. Dimmeler2, S. Cremer1

1Med. Klinik III - Kardiologie, Angiologie, Universitätsklinikum Frankfurt, Frankfurt am Main; 2Zentrum für Molekulare Medizin, Institut für Kardiovaskuläre Regeneration, Goethe Universität Frankfurt am Main, Frankfurt am Main; 3Institute of Cardiovascular Regeneration, Goethe Universität Frankfurt am Main, Frankfurt am Main; 4Kardiovaskuläre Bildgebung, Universitätsklinikum Frankfurt, Frankfurt am Main;

Background: The prevalence of heart failure with preserved ejection fraction (HFpEF) is rising worldwide and accounts for half of all heart failure cases. In contrast to heart failure with reduced ejection fraction (HFrEF), approved medical therapies for HFpEF are scarce, and there is an unmet need for novel treatment options. Maladaptive cardiac fibrosis is central to the pathology of HFpEF. The contribution of myeloid cells to the development of HFpEF in humans has not been studied in detail so far. Methods: Single-nuclei RNA sequencing (snRNA-seq) of cardiac biopsies from patients with HFpEF was performed and merged with a publicly available dataset of healthy hearts. Single-nuclei transcriptomes were analyzed by R using the Seurat package. For gene ontology analysis, Metascape was used. Ligand-receptor analysis was conducted by the CellChat package for R. For in-vitro studies self-assembling human iPSC-derived cardiac organoids were used. HFpEF in human iPSC-derived cardiac organoids was induced using a high-fat (200µM Palmitate) and L-NAME (2.1 mM)-supplemented medium. Genes of interest were analyzed by qPCR. Results: We performed single-nuclei RNA sequencing of cardiac tissue from patients with HFpEF and the resulting data were merged with a publicly available dataset of healthy hearts (total: 69918 nuclei). Macrophages were annotated using published myeloid cell markers. Differentially expressed gene analysis of macrophages revealed a significant upregulation of total 1638 genes in HFpEF (cut-off: adjusted p-value<0,05). Among the upregulated genes, proinflammatory receptors like Toll-like receptors and Interleukin receptors were present. In addition, we found an upregulation of the profibrotic mediators Platelet-derived growth factor B and C (PDGFB: 1,4, PDGFC: 3,5, all fold change, p<2,7x10-26). Gene ontology analysis revealed dysregulation of “signal transduction by growth factors” and “PDGFRB pathway” as key regulated pathways. For maladaptive fibrosis, cell-cell communication between various cell types in the heart including immune cells and fibroblasts is mandatory. Therefore, we performed in-silico ligand-receptor analysis with the bioinformatic tool CellChat. The top predicted ligand-receptor pairs between macrophages and fibroblasts were macrophage-derived PDGFs and their corresponding receptors on fibroblasts. To gain further insight into the role of macrophage derived PDGFs in cardiac fibrosis in HFpEF, we treated self-assembling human iPSC-derived cardiac organoids for 7 days with recombinant PDGF-B and C. PDGF-B induced significant upregulation of collagens (COL1A1, COL3A1, COL4A1) and the myofibroblasts marker ACTA1 (p<0,05). For PDGF-C, the same trend was observed, reaching statistical significance for COL4A1 (p<0,05). To validate our findings from the snRNA-seq of human HFpEF, we induced HFpEF in iPSC-derived cardiac organoids using an established HFpEF model. In accordance with our snRNA-seq data, HFpEF organoids showed significant overexpression of PDGFB (p<0.05) and a trend to more expression of PDGFC. Conclusions: Our data, for the first time, dissect human HFpEF on a single cell level. Using bioinformatic tools, we identified the PDGF-PDGFR axis as a central mediator of macrophage-fibroblast interactions in HFpEF. In-vitro experiments validated the role of PDGFs in promoting cardiac fibrosis. We will test approved PDGF inhibitors in a drug-repurposing approach in-vitro and in-vivo to target fibrosis in HFpEF.

https://dgk.org/kongress_programme/jt2023/aV1520.html