Regensburg 2025 – scientific programme

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BP: Fachverband Biologische Physik

BP 11: Cytoskeleton

BP 11.7: Talk

Tuesday, March 18, 2025, 11:15–11:30, H44

Investigating the interaction between two single heart cells through TNTs using ROCS and Fluorescence microscopy — •Arash Felekary and Alexander Rohrbach — Lab for Bio and Nano Photonics, IMTEK, Freiburg, Germany

Cell-cell communication is vital for biological processes, particularly in the heart. Tunneling nanotubes (TNTs), dynamic and thin protrusions, facilitate cellular interactions by transferring organelles, including mitochondria. To investigate TNT composition and their roles in cardiac fibroblast (FB) communication, we employed Rotating Coherent Scattering (ROCS) microscopy, a label-free super-resolution technique, in addition to Fluorescence microscopy. ROCS enables up to 100 Hz recordings of lamellipodia dynamics along TNTs, and 3D imaging across different z-planes up to 6μm in depth, which is critical for visualizing TNTs. We observed a linear correlation between TNT density and lamellipodia motion velocity. Lamellipodia, driven by actin polymerization and branching via Arp2/3 activation, play a key role in FB migration and interaction. Collagen staining demonstrated that TNTs and lamellipodia interact with collagen fibers, a major component of the extracellular matrix (ECM). This interaction not only influences ECM remodeling, but also activates actin branching signals that enhance FB migration and protrusion dynamics. In this presentation, we investigate the coordinated roles of TNTs, lamellipodia, and collagen in regulating FB interaction and migration, offering new insights into heart tissue repair.

Keywords: Cardiac Fibroblasts; Tunneling Nanotubes (TNTs); ROCS Microscopy; Cell-Cell Communication; Extracellular Matrix (ECM)