Abstract 12532: Extracellular Vesicles Released by Cardiosphere-Derived Cells Dampen the Pro-Inflammatory Monocyte Response Through Repression of C-C Chemokine Receptor Type 2 (CCR2)

• Published in: Circulation (New York, N.Y.) N.Y.), 2021-11, Vol.144 (Suppl_1), p.A12532-A12532
• Main Authors: Mentkowski, Kyle I, Pandey, Rohan, Schiffmacher, Paul J, Eagler, Lisa A, Reynolds, Jessica L, Lang, Jennifer K
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.144.suppl_1.12532

BackgroundFollowing a myocardial infarction (MI), CCR2+ monocytes migrate toward the injury site along a CCL2 concentration gradient and play an integral role in removing debris and facilitating repair. Although required to orchestrate the pro-inflammatory response, prolonged activation of CCR2+ monocytes can lead to adverse outcomes. Extracellular vesicles (EVs) derived from cardiosphere-derived cells (CDCs) have been suggested to mediate cardioprotection in part via immunomodulation. We hypothesized that CDC-EVs influence CCR2+ monocyte recruitment and function. MethodsBlood samples were obtained from healthy human donors under approved institutional IRBs. Human monocytes were isolated from peripheral blood using density gradient centrifugation (Ficoll) followed by magnetic activated cell sorting (MACS). EVs were isolated from CDCs, normal human dermal fibroblasts (NHDFs, an inert population in models of ischemia), and CDCs transfected with a miR-146a antagomir. EVs were characterized according to established guidelines for size, morphology and protein expression. Monocytes were incubated with PBS, NHDF-EVs, CDC-EVs, or miR-146a deficient CDC-EVs and analyzed for CCR2 protein expression by flow cytometry and western blot and migration along a CCL2/MCP-1 gradient by in vitro chemotaxis assays. ResultsCDC-EVs significantly reduced CD14hiCD16- monocyte surface expression of CCR2 by 50% as quantified by flow cytometry when compared with PBS and NHDF-EVs (p