TUNNELING NANOTUBES AN EMERGING INTERCELLULAR ROUTE FOR THE EXCANGE OF COMPONENT BETWEEN NEIGHBORING CELLS CHARACTERIZED IN MESENCHYMAL STEM CELLS

LUZZANI, CARLOS; GELPI, RICARDO J.; PODEROSO, JUAN JOSE; SANCHEZ, VIVIANA; FIORE, LUCIANO; BRUSCO ALICIA; VILLALBA, NERINA; MIRIUKA, SANTIAGO; BOVERIS, ALBERTO

Mar del Plata

Congreso; SAIC 2016; 2016

SAIC

Intercellular communication is one of the most important events in cell population behavior.In the last decade, tunneling nanotubes (TNTs) have emerged as a newly discovered form oflong distance intercellular connection. TNTs transfer molecules and organelles such as calciumions, prions, viral and bacterial pathogens, small lysosomes and mitochondria betweenneighboring cells. New findings suggest that the ability of mesenchymal stem cells (MSCs) toalter tissue microenvironment via the secretion of soluble factors or transfer of their owncellular components to neighboring cells may contribute significantly to tissue repair, althoughthe underlying mechanisms remain poorly understood. In this work we present an extensive anddetailed description of types, structure, components, dynamics and functionality of TNTsbridging neighboring human Wharton Jelly MSCs (WJ-MSC) using phase contrast, fluorescenceand electron microscopy, as well as time lapse images. Our results show that TNTs either extendbetween two neighboring cells or form a network connecting various neighboring cells. In bothcases, they exhibited a long rectilinear extension whose length ranged between 100 and 700μm . Two different types of TNTs were identified: one containing only actin filament cytoskeleton(Type I), and the other with both actin and tubulin filaments (Type II). In vivo time lapse imagingemploying a mitochondrial marker allowed us to see mitochondria lining up and moving alongTNTs at a velocity of 0.8 ± 0.2 μm / min. As sh own by ultrastructural analysis, Type I TNTs did notexceed 100-nm diameter and had no organelles inside, while Type II TNTs had 600-700nmdiameter and contained polyribosomes, rough endoplasmic reticulum, vesicles, mitochondriaand lipid drops. Caveoles were present on the cell surface of both types of TNTs. MSCs havemany advantages for implementation in regenerative medicine and TNTs in this cell type mayconstitute a suitable route.