title: Different populations of Wnt-containing vesicles are individually released from polarized epithelial cells.
abstract: Accumulating evidence suggests that exosomes are heterogeneous in molecular composition and physical properties. Here we examined whether epithelial cells secrete a heterogeneous population of exosomes, and if that is the case, whether epithelial cell polarity affects release of different populations of exosomes, especially that of those carrying Wnt. Sucrose-density ultracentrifugation and molecular marker analysis revealed that different populations of exosomes or exosome-like vesicles were released from MDCK cells depending on the cell polarity. Wnt3a associated with these vesicles were detectable in culture media collected from both apical and basolateral sides of the cells. Basolaterally secreted Wnt3a were co-fractionated with a typical exosomal protein TSG101 in fractions having typical exosome densities. In contrast, most of apically secreted Wnt3a, as well as Wnt11, were co-fractionated with CD63 and Hsp70, which are also common to the most exosomes, but recovered in higher density fractions. Wnt3a exhibiting similar floatation behavior to the apically secreted ones were also detectable in the culture media of Wnt3a-expressing L and HEK293 cells. The lipidation of Wnt3a was required for its basolateral secretion in exosomes but was dispensable for the apical one. Thus, epithelial cells release Wnt via distinct populations of vesicles differing in secretion polarity and lipidation dependency.
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Takada
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
authors.forename: Chiyo
authors.initials: C
authors.lastname: Noda
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan.|Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.|The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takada
mesh_terms: D000818:Animals; D016764:Cell Polarity; D055252:Cell-Derived Microparticles / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism*; D055354:Exosomes / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D054878:Lipoylation / Q000235:genetics; D061985:Madin Darby Canine Kidney Cells; D051379:Mice; D060149:Tetraspanin 30 / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D060509:Wnt3A Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C554587:Cd63 protein, mouse; D018840:HSP70 Heat-Shock Proteins; D060149:Tetraspanin 30; D051153:Wnt Proteins; C508957:Wnt11 protein, mouse; D060509:Wnt3A Protein; C555511:Wnt3a protein, mouse