title: Rho kinase inhibitor Y27632 affects initial heart myofibrillogenesis in cultured chick blastoderm.
abstract: During early vertebrate development, Rho-associated kinases (ROCKs) are involved in various developmental processes. Here, we investigated spatiotemporal expression patterns of ROCK1 protein and examined the role of ROCK during initial heart myofibrillogenesis in cultured chick blastoderm. Immunohistochemistry showed that ROCK1 protein was distributed in migrating mesendoderm cells, visceral mesoderm of the pericardial coelom (from which cardiomyocytes will later develop), and cardiomyocytes of the primitive heart tube. Pharmacological inhibition of ROCK by Y27632 did not alter the myocardial specification process in cultured posterior blastoderm. However, Y27632 disturbed the formation of striated heart myofibrils in cultured posterior blastoderm. Furthermore, Y27632 affected the formation of costamere, a vinculin/integrin-based rib-like cell adhesion site. In such cardiomyocytes, cell-cell adhesion was disrupted and N-cadherin was distributed in the perinuclear region. Pharmacological inactivation of myosin light chain kinase, a downstream of ROCK, by ML-9 perturbed the formation of striated myofibrils as well as costameres, but not cell-cell adhesion. These results suggest that ROCK plays a role in the formation of initial heart myofibrillogenesis by means of actin-myosin assembly, and focal adhesion/costamere and cell-cell adhesion.
authors.affiliation: Department of Anatomy and Cell Biology, Graduate School of Medicine, Osaka City University, Asahimachi, Osaka, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Sakata
authors.forename: Masahide
authors.initials: M
authors.lastname: Sakabe
authors.forename: Hiroko
authors.initials: H
authors.lastname: Matsui
authors.forename: Norifumi
authors.initials: N
authors.lastname: Kawada
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nakatani
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ikeda
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yamagishi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakajima
mesh_terms: D000577:Amides / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001756:Blastoderm / Q000378:metabolism* / Q000502:physiology; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D002642:Chick Embryo; D017931:DNA Primers; D019084:Fluorescent Antibody Technique, Indirect; D006321:Heart / Q000196:embryology*; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D024510:Muscle Development / Q000187:drug effects / Q000502:physiology*; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011725:Pyridines / Q000378:metabolism / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D001381:Azepines; D017931:DNA Primers; D047908:Intracellular Signaling Peptides and Proteins; D011725:Pyridines; C056218:ML 9; C108830:Y 27632; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase