Abstract P2061: The Long Non-coding RNA Schlafenlnc As A Regulator Of Cardiac Resident Macrophage Function

Abstract

Introduction: Cardiac resident macrophages (crMΦs) constitute up to 5% of cells in the murine heart and were shown to play key roles in cardiac homeostasis and disease. Long non-coding RNAs (lncRNAs) are regulatory molecules that impact characteristics such as cell identity, proliferation or migration. However, the function of lncRNAs in crMΦ remains enigmatic. Objective: We sought to identify crMΦ-specific lncRNAs and analyze their function in vitro and in vivo to understand their role during health and cardiac disease. Methods and Results: Using RNASeq (>100 million reads/sample) of purified murine crMΦs and single cell Seq of total murine myocardium in health and disease, we could identify the lncRNA Schlafenlnc as a highly enriched and abundant lncRNA in crMΦs. Employing the CRISPR-Cas system we successfully deleted the full Schlafenlnc locus in a macrophage progenitor cell line. Next, we performed RNASeq of Schlafenlnc -/- macrophages and could observe 2,660 significantly deregulated genes that were enriched in genes associated with chemotaxis and migration. In line with these findings, Schlafenlnc -/- macrophages displayed decreased chemotaxis as well as adhesion using cell-based assays. Furthermore, using RNA-pulldown experiments followed by mass spectrometry analysis and we could identify 27 interaction partners of Schlafenlnc , which are involved in processes such as mRNA processing, transcriptional regulation and alternative splicing. Finally, we are currently using cardiac functional measurements, macrophage stainings as well as single cell Seq during health and cardiac disease to analyze the function of Schlafenlnc in vivo. Conclusion: In this study, we could identify the crMΦ-specific lncRNA Schlafenlnc as a critical regulator of macrophage migratory functions. Therapeutic targeting of the evolutionary conserved lncRNA Schlafenlnc might therefore be beneficial in the treatment of inflammatory cardiac diseases.