title: Basal filopodia and vascular mechanical stress organize fibronectin into pillars bridging the mesoderm-endoderm gap.
abstract: Cells may exchange information with other cells and tissues by exerting forces on the extracellular matrix (ECM). Fibronectin (FN) is an important ECM component that forms fibrils through cell contacts and creates directionally biased geometry. Here, we demonstrate that FN is deposited as pillars between widely separated germ layers, namely the somitic mesoderm and the endoderm, in quail embryos. Alongside the FN pillars, long filopodia protrude from the basal surfaces of somite epithelial cells. Loss-of-function of Ena/VASP, α5β1-integrins or talin in the somitic cells abolished the FN pillars, indicating that FN pillar formation is dependent on the basal filopodia through these molecules. The basal filopodia and FN pillars are also necessary for proper somite morphogenesis. We identified a new mechanism contributing to FN pillar formation by focusing on cyclic expansion of adjacent dorsal aorta. Maintenance of the directional alignment of the FN pillars depends on pulsatile blood flow through the dorsal aortae. These results suggest that the FN pillars are specifically established through filopodia-mediated and pulsating force-related mechanisms.
authors.affiliation: Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan satoyuki@anat1.med.kyushu-u.ac.jp.|JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Yuki
authors.identifier: 0000-0001-8974-2059
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nagatoshi
authors.affiliation: Department of Advanced Information Technology, Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0385, Japan.
authors.forename: Ayumi
authors.identifier: 0000-0002-7115-0626
authors.initials: A
authors.lastname: Hamano
authors.affiliation: Graduate School of Science, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Imamura
authors.affiliation: Department of Radiology and Developmental Neuroscience Program, Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.|Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: David
authors.initials: D
authors.lastname: Huss
authors.affiliation: Department of Advanced Information Technology, Faculty of Information Science and Electrical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0385, Japan.
authors.forename: Seiichi
authors.identifier: 0000-0001-8592-7566
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Department of Radiology and Developmental Neuroscience Program, Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.|Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Rusty
authors.identifier: 0000-0002-2159-3699
authors.initials: R
authors.lastname: Lansford
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001808:Blood Vessels / Q000502:physiology*; D002465:Cell Movement; D004625:Embryo, Nonmammalian; D004707:Endoderm / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism*; D009024:Morphogenesis; D011554:Pseudopodia / Q000502:physiology*; D011784:Quail / Q000196:embryology*; D013314:Stress, Mechanical
chemical_list: D005353:Fibronectins
keywords: Dorsal aorta; Endoderm; Fibronectin; Filopodia; Somite