title: Lipid droplets as a novel cargo of tunnelling nanotubes in endothelial cells.
abstract: Intercellular communication is a fundamental process in the development and functioning of multicellular organisms. Recently, an essentially new type of intercellular communication, based on thin membrane channels between cells, has been reported. These structures, termed intercellular or tunnelling nanotubes (TNTs), permit the direct exchange of various components or signals (e.g., ions, proteins, or organelles) between non-adjacent cells at distances over 100 μm. Our studies revealed the presence of tunnelling nanotubes in microvascular endothelial cells (HMEC-1). The TNTs were studied with live cell imaging, environmental scanning electron microscopy (ESEM), and coherent anti-Stokes Raman scattering spectroscopy (CARS). Tunneling nanotubes showed marked persistence: the TNTs could connect cells over long distances (up to 150 μm) for several hours. Several cellular organelles were present in TNTs, such as lysosomes and mitochondria. Moreover, we could identify lipid droplets as a novel type of cargo in the TNTs. Under angiogenic conditions (VEGF treatment) the number of lipid droplets increased significantly. Arachidonic acid application not only increased the number of lipid droplets but also tripled the extent of TNT formation. Taken together, our results provide the first demonstration of lipid droplets as a cargo of TNTs and thereby open a new field in intercellular communication research.
authors.affiliation: Department of Pharmacy, Pharmaceutical Biology, Saarland University, Saarbrücken, Germany.
authors.forename: Ksenia
authors.initials: K
authors.lastname: Astanina
authors.affiliation: Leibniz Institute for New Materials, Saarbrücken, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Koch
authors.affiliation: Department of Chemistry, Konstanz University, Konstanz, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Jüngst
authors.affiliation: Department of Chemistry, Konstanz University, Konstanz, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Zumbusch
authors.affiliation: Department of Pharmacy, Pharmaceutical Biology, Saarland University, Saarbrücken, Germany.
authors.forename: Alexandra K
authors.initials: AK
authors.lastname: Kiemer
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D016718:Arachidonic Acid / Q000494:pharmacology; D001692:Biological Transport; D015820:Cadherins / Q000037:antagonists & inhibitors / Q000378:metabolism; D002450:Cell Communication / Q000502:physiology*; D002460:Cell Line; D003599:Cytoskeleton / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D007365:Intercellular Junctions / Q000378:metabolism*; D066292:Lipid Droplets / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes; D013059:Spectrum Analysis, Raman; D013229:Stearic Acids / Q000494:pharmacology; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D016718:Arachidonic Acid; D015820:Cadherins; D013229:Stearic Acids; D000099152:Cadherin 5; C031183:stearic acid