Selective Surface and Intraluminal Localization of Wnt Ligands on Small Extracellular Vesicles Released by HT-22 Hippocampal Neurons

• DOI: 10.3389/fcell.2021.735888
• Publication Date: 2021-10-13T18:18:57Z
• Authors: Viviana I. Torres; Daniela P. Barrera; Manuel Varas-Godoy; Duxan Arancibia; Nibaldo C. Inestrosa
• Keywords: Exosome; Tetraspanin; Palmitoylation; Extracellular vesicles

The Wnt signaling pathway induces various responses underlying the development and maturation of nervous system. ligands are highly hydrophobic proteins that limit their diffusion through an aqueous extracellular medium to a target cell. Nevertheless, attachment small vesicles-like exosomes is one described mechanisms allow transport under this condition. Some in these vehicles expected be dependent on post-translational modifications such as acylation. determining loading delivery cells largely unknown. Here, we took advantage cell model secret enriched population vesicles (sEVs), hippocampal HT-22 neurons. First, establish model, characterized morphological biochemical properties fraction sEVs obtained from neurons express NCAM-L1, specific exosomal neuronal marker. Transmission electron microscopy showed exosome-like vesicles. Next, presence Wnt3a, Wnt5a, Wnt7a was confirmed by western blot analysis combined with immunogold. Also, studied whether palmitoylation necessary modification for We found proteinase-K treatment selectively decreased Wnt5a content, suggesting expression delimited exterior membrane surface. In contrast, Wnt3a remained attached, it localized within exosome lumen. On other hand, Wnt-C59, inhibitor porcupine O-acyltransferase (PORCN), association exosomes, ligand acylation them secreted exosomes. These findings may help understand action cell, which could defined during packaging secretory sEVs.