The primary cilium coordinates early cardiogenesis and hedgehog signaling in cardiomyocyte differentiation.
Defects in the assembly or function of primary cilia, which are sensory organelles, are tightly coupled to developmental defects and diseases in mammals. Here, we investigated the function of the primary cilium in regulating hedgehog signaling and early cardiogenesis. We report that the pluripotent P19.CL6 mouse stem cell line, which can differentiate into beating cardiomyocytes, forms primary cilia that contain essential components of the hedgehog pathway, including Smoothened, Patched-1 and Gli2. Knockdown of the primary cilium by Ift88 and Ift20 siRNA or treatment with cyclopamine, an inhibitor of Smoothened, blocks hedgehog signaling in P19.CL6 cells, as well as differentiation of the cells into beating cardiomyocytes. E11.5 embryos of the Ift88(tm1Rpw) (Ift88-null) mice, which form no cilia, have ventricular dilation, decreased myocardial trabeculation and abnormal outflow tract development. These data support the conclusion that cardiac primary cilia are crucial in early heart development, where they partly coordinate hedgehog signaling.
Clement
Christian A
CA
Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Kristensen
Stine G
SG
Møllgård
Kjeld
K
Pazour
Gregory J
GJ
Yoder
Bradley K
BK
Larsen
Lars A
LA
Christensen
Søren T
ST
D000818:Animals; D002454:Cell Differentiation; D002923:Cilia / Q000235:genetics / Q000378:metabolism*; D006321:Heart / Q000196:embryology; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; D039904:Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000072086:Smoothened Receptor; D000075746:Zinc Finger Protein Gli2
C000618551:Gli2 protein, mouse; D053823:Hedgehog Proteins; D051741:Kruppel-Like Transcription Factors; D000072079:Patched Receptors; D000072081:Patched-1 Receptor; C000606240:Ptch1 protein, mouse; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; C491022:Smo protein, mouse; D000072086:Smoothened Receptor; D000075746:Zinc Finger Protein Gli2