Abstract P3055: Identification Of Cell-intrinsic Effects Of Clonal Hematopoiesis In Heart Failure

Abstract

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is caused by somatic mutations in hematopoietic stem cells and associates with worse prognosis in patients with heart failure (HF). While, circulating immune cells derived from patients with HF harboring CHIP mutations show heightened proinflammatory signatures, it is unclear whether these signatures are derived from the relatively low number of cells harboring CHIP-driver mutations, or are indicators of a systemic pro-inflammatory activation associated with CHIP. Methods and Results: We assessed the cell-intrinsic effects of the most prevalent CHIP-driver gene (DNMT3A) mutant-carrying circulating immune cells in a total of 5 HF patients. Using a novel protocol to detect DNMT3A mutant cells on a single cell level (MutDetect-Seq), we show that CHIP mutations can be detected in all major immune cell types (e.g. T cells, monocytes, B cells, NK cells), with detected mutation similar to that predicted by traditional targeted DNA sequencing. DNMT3A mutant monocytes demonstrated the highest number of significantly upregulated genes relative to other cell types. DNMT3A mutant monocytes exhibit altered gene expression signatures associated with inflammation and phagolysosome function. Additionally, DNMT3A mutant carrying CD4+, but not CD8+ T cells, showed significant changes in gene expression patterns towards an activated and cytotoxic profile, which was validated in vitro. Finally, increased paracrine signaling pathways involved in amplifying inflammatory circuits are predicted between mutated and non-mutated monocytes, this was validated in vitro with further implications for cardiac fibroblast activation via aSMA and COL1A1 expression. Conclusion: This is the first study to decipher the genetic signature of DNMT3A-CHIP-driver mutation carrying circulating immune cells, thereby providing first evidence for the cell intrinsic effects of DNMT3A mutations on peripheral blood cell subsets in patients with HF. The altered gene expression profiles associated with inflammation and phagolysosome function of mutant monocyte, as well as skewing of mutated T cells towards effector cells provide novel insights into how CHIP may promote worse prognosis in heart failure patients.