Modulation of RUNX1-dependent Regulatory Elements in Cardiac Fibroblasts

• Applicant: Professor Dr. Ralf Gilsbach
• Subject Area: Cardiology, Angiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 558598989

Cardiac fibrosis is a common hallmark of heart disease. It plays a protective role in heart disease by replacing dead cells with scar tissue, thereby preserving the heart's structural integrity. In contrast, excess production of collagen-rich scar tissue adversely impacts heart function and patient survivability. The activation of fibroblasts is of central importance for developing cardiac fibrosis. Transcription factors like RUNX1 (RUNX Family Transcription Factor 1) are main drivers of fibroblast activation. RUNX1 mediates fibroblast activation by modulation of the activity of gene promoters and distal regulatory elements. These signaling pathways can manifest in the epigenome of fibroblasts and alter their activity in the long term. This project aims to decode the trajectories of fibroblast activation on the epigenetic and transcriptomic level for different lesion types and to modulate these pathways using CRISPR interference with a focus on RUNX1-dependent gene regulatory elements. In work package 1, we will combine multimodal single-cell and spatial analysis with FB lineage tracing to decode common and distinct trajectories of FB activation in cardiac lesions resulting from different insults on the transcriptional and epigenetic layer. This project part will predict RUNX1-dependent regulatory elements as targets for work package 2. Including non-FB cells in the analysis will allow the prediction of the involved heterocellular interactions. In work package 2, we will use CRISPR-based functional epigenetic methods to modulate the activity and spatial interactions of RUNX1-dependent regulatory elements. We will optimize AAV vectors and delivery routes to deliver these constructs to FB efficiently. This will allow testing of the impact of functional epigenetic modulation on scar formation in vivo. We will include RUNX1-dependent regulatory elements identified in our preliminary work and sites identified in work package 1. The impact of CRISPR-based modulation will be studied on the epigenetic layer with single-cell resolution and on the functional level in vivo. In summary, this project will decode the trajectories of FB activation on the epigenome and transcriptome levels and establish functional epigenetic methods to modulate these trajectories with a focus on RUNX1-dependent signaling events and a vision of modifying scar properties.

• DFG Programme: Research Grants