title: Vertebrate Hedgehog is secreted on two types of extracellular vesicles with different signaling properties.
abstract: Hedgehog (Hh) is a secreted morphogen that elicits differentiation and patterning in developing tissues. Multiple proposed mechanisms to regulate Hh dispersion includes lipoprotein particles and exosomes. Here we report that vertebrate Sonic Hedgehog (Shh) is secreted on two types of extracellular-vesicles/exosomes, from human cell lines and primary chick notochord cells. Although largely overlapping in size as estimated from electron micrographs, the two exosomal fractions exhibited distinct protein and RNA composition. We have probed the functional properties of these vesicles using cell-based assays of Hh-elicited gene expression. Our results suggest that while both Shh-containing exo-vesicular fractions can activate an ectopic Gli-luciferase construct, only exosomes co-expressing Integrins can activate endogenous Shh target genes HNF3β and Olig2 during the differentiation of mouse ES cells to ventral neuronal progenitors. Taken together, our results demonstrate that primary vertebrate cells secrete Shh in distinct vesicular forms, and support a model where packaging of Shh along with other signaling proteins such as Integrins on exosomes modulates target gene activation. The existence of distinct classes of Shh-containing exosomes also suggests a previously unappreciated complexity for fine-tuning of Shh-mediated gradients and pattern formation.
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Vyas
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Ankita
authors.initials: A
authors.lastname: Walvekar
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Tate
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Vairavan
authors.initials: V
authors.lastname: Lakshmanan
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Dhiru
authors.initials: D
authors.lastname: Bansal
authors.affiliation: 1] Institut Curie, UMR 144, CNRS, F-75248 Paris, France [2] Structure and Membrane Compartments, Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France [3] Cell and Tissue Imaging Facility, Infrastructures en Biologie Sante et Agronomie (IBiSA), Paris F-75248, France.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lo Cicero
authors.affiliation: 1] Institut Curie, UMR 144, CNRS, F-75248 Paris, France [2] Structure and Membrane Compartments, Centre National de la Recherche Scientifique, UMR144, Paris F-75248, France [3] Cell and Tissue Imaging Facility, Infrastructures en Biologie Sante et Agronomie (IBiSA), Paris F-75248, France.
authors.forename: Graca
authors.initials: G
authors.lastname: Raposo
authors.affiliation: Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India.
authors.forename: Dasaradhi
authors.initials: D
authors.lastname: Palakodeti
authors.affiliation: 1] Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India [2] CSIR-Center for Cellular and Molecular Biology, Hyderabad, India.
authors.forename: Jyotsna
authors.initials: J
authors.lastname: Dhawan
mesh_terms: D000818:Animals; D002642:Chick Embryo; D055354:Exosomes / Q000235:genetics / Q000378:metabolism*; D005110:Extracellular Space; D057809:HEK293 Cells; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism; D008954:Models, Biological; D021381:Protein Transport; D015398:Signal Transduction; D014714:Vertebrates
chemical_list: D053823:Hedgehog Proteins; D035683:MicroRNAs