Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France; ESPCI Paris, PSL University, CNRS, Institut Langevin, Paris, France
Ludovic Keiser
Laboratory of Fluid Mechanics and Instabilities, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Yasmine Cantaut-Belarif
Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
Martin Carbo-Tano
Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
Frederik Verweij
Institute of Psychiatry and Neuroscience of Paris, Hôpital Saint-Anne, Université Descartes, INSERM U1266, Paris, France
Kavli Institute for Systems Neuroscience, Centre for Neural Computation, The Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Clinical and Molecular Medicine, The Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway
Pierre-Luc Bardet
Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
Guillaume van Niel
Institute of Psychiatry and Neuroscience of Paris, Hôpital Saint-Anne, Université Descartes, INSERM U1266, Paris, France
Francois Gallaire
Laboratory of Fluid Mechanics and Instabilities, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Institut du Cerveau et de la Moelle épinière (ICM), Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
Circulation of the cerebrospinal fluid (CSF) contributes to body axis formation and brain development. Here, we investigated the unexplained origins of the CSF flow bidirectionality in the central canal of the spinal cord of 30 hpf zebrafish embryos and its impact on development. Experiments combined with modeling and simulations demonstrate that the CSF flow is generated locally by caudally-polarized motile cilia along the ventral wall of the central canal. The closed geometry of the canal imposes the average flow rate to be null, explaining the reported bidirectionality. We also demonstrate that at this early stage, motile cilia ensure the proper formation of the central canal. Furthermore, we demonstrate that the bidirectional flow accelerates the transport of particles in the CSF via a coupled convective-diffusive transport process. Our study demonstrates that cilia activity combined with muscle contractions sustain the long-range transport of extracellular lipidic particles, enabling embryonic growth.
