Genética del Desarrollo Neural

Guillermo Lanuza - Fundación Instituto Leloir

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  El sistema nervioso central está compuesto por una llamativa diversidad de tipos de neuronas y células de la glia que se ensamblan en circuitos neuronales funcionales. La generación de diversidad neuronal y glial resulta de una serie integrada de pasos de desarrollo que controla la diferenciación de progenitores o células madre neurales, la adquisición de identidades neuronales específicas, la extensión de procesos axonales y el establecimiento de conexiones sinápticas. Nuestro objetivo es entender los mecanismos básicos que subyacen a diferentes aspectos de estos eventos. Estos estudios contribuyen a entender cómo se desarrollan los circuitos del sistema nervioso y contribuyen al diseño de potenciales estrategias terapeúticas de patologías y daños del sistema nervioso. Nuestras investigaciones se centran fundamentalmente en dos regiones del sistema nervioso central: el cerebro posterior y el cordón espinal que albergan circuitos neuronales que son esenciales para el control motor y para el procesamiento de señales sensoriales. Nuestro objetivo es identificar reguladores transcripcionales y vías de señalización cuya función organiza la creación de diversidad celular en el sistema nervioso. Nuestros modelos experimentales son el ratón y el pollo, y utilizamos abordajes combinados de biología molecular, bioquímica, genética molecular y fisiología.  

1. Late neurogenesis in the developing mammalian spinal cord: the origin an specification of central canal neurons 

1a. The Late and Dual Origin of Cerebrospinal Fluid-contacting Neurons in the Mouse Spinal Cord

Considerable progress has been made in understanding the mechanisms that control the production of specialized neuronal types. However, how the timing of differentiation contributes to neuronal diversity in the developing spinal cord is still a pending question. In this study, we show that CerebroSpinal Fluid-contacting Neurons (CSF-cNs), an anatomically discrete cell type of the ependymal area, originate from surprisingly late neurogenic events in the ventral spinal cord. CSF-cNs are identified by the expression of the transcription factors Gata2 and Gata3, and the ionic channels PKD2L1 and PKD1L2. Contrasting with Gata2/3+ V2b interneurons, CSF-cNs differentiation is independent of Foxn4 and takes place during advanced developmental stages previously assumed to be exclusively gliogenic. CSF-cNs are produced from two distinct dorso-ventral regions of the mouse spinal cord. Most CSF-cNs derive from progenitors circumscribed to the late-p2 and the oligodendrogenic (pOL) domains, whereas a second subset of CSF-cNs arises from cells bordering the floor plate. The development of these two subgroups of CSF-cNs is differentially controlled by Pax6, they adopt separate locations around the postnatal central canal and display electrophysiological differences. Our results highlight that spatio-temporal mechanisms are instrumental in creating neural cell diversity in the ventral spinal cord to produce distinct classes of interneurons, motoneurons, CSF-cNs, glial and ependymal cells. Reference: Petracca, Saroretti, et al. Development (2016)   1b. Ascl1 balances neuronal vs. ependymal fate in the spinal cord central canal The generation of neuronal cell types at the right time, location and number is essential for building a functional nervous system. Significant progress has been reached in understanding the genetic mechanisms that govern neuronal diversity. CerebroSpinal Fluid-contacting Neurons (CSF-cNs), an intriguing specialized population of the spinal cord central canal, are produced during advanced developmental stages, simultaneous with glial and ependymal cells. It is unknown how late-born CSF-cNs are specified and how progenitors acquire neuronal potential after the neurogenic-to-gliogenic switch. Here, we identified that delayed expression of the transcription factor Ascl1 in mouse spinal progenitors during the gliogenic phase is key in CSF-cN differentiation. With fate mappings and time-controlled deletions, we demonstrate that CSF-cNs derive from Ascl1-expressing cells and that Ascl1 triggers late neurogenesis in the amniote spinal cord. Abrogation of Ascl1 transforms prospective CSF-cN progenitors into ependymocytes. These results demonstrate that late spinal progenitors have the potential to produce neurons and that Ascl1 initiates CSF-cN differentiation, controlling the precise neuronal and non-neuronal composition of the spinal cord central canal. Reference: Di Bella, Carcagno, at al. Cell Reports (2019)  

 2. Neuronal specification in ventral hindbrain and spinal cord

2a. Neurogenin3 restricts serotonergic neuron differentiation to the hindbrain In the developing neural tube, hindbrain serotonergic neurons and spinal glutamatergic V3 interneurons are produced from ventral p3 progenitors, which possess a common transcriptional identity but are confined to distinct anterior-posterior territories. In this study, we show that the expression of the transcription factor Neurogenin3 (Neurog3) in the spinal cord controls the correct specification of p3-derived neurons. Gain- and loss-of-function manipulations in the mouse and chick embryo show that Neurog3 switches ventral progenitors from a serotonergic to V3 differentiation program by repressing Ascl1 in spinal p3 progenitors through a mechanism dependent on Hes proteins. In this way, Neurog3 establishes the posterior boundary of the serotonergic system by actively suppressing serotonergic specification in the spinal cord. These results explain how equivalent p3 progenitors within the hindbrain and the spinal cord produce functionally distinct neuron cell types. Reference: Carcagno, at al. Journal of Neuroscience (2014) 2b. Sim1 is required for the migration and axonal projections of V3 interneurons in the developing mouse spinal cord V3 spinal interneurons (INs) are a group of excitatory INs that play a crucial role in producing balanced and stable gaits in vertebrate animals. In the developing mouse spinal cord, V3 INs arise from the most ventral progenitor domain and form anatomically distinctive subpopulations in adult spinal cords. They are marked by the expression of transcription factor Sim1 postmitotically, but the function of Sim1 in V3 development remains unknown. Here, we used Sim1Cre;tdTomato mice to trace the fate of V3 INs in a Sim1 mutant versus control genetic background during development. In Sim1 mutants, V3 INs are produced normally and maintain a similar position and organization as in wild types before E12.5. Further temporal analysis revealed that the V3 INs in the mutants failed to migrate properly to form V3 subgroups along the dorsoventral axis of the spinal cord. At birth, in the Sim1 mutant the number of V3 INs in the ventral subgroup was normal, but they were significantly reduced in the dorsal subgroup with a concomitant increase in the intermediate subgroup. Retrograde labeling at lumbar level revealed that loss of Sim1 led to a reduction in extension of contralateral axon projections both at E14.5 and P0 without affecting ipsilateral axon projections. These results demonstrate that Sim1 is essential for proper migration and the guidance of commissural axons of the spinal V3 INs. Reference: Blacklaws, et al Devel Neurobiol (2015)  

  Ascl1 balances neuronal vs. ependymal fate in the spinal cord central canal. Di-Bella DJ*, Carcagno AL*, Bartolomeu ML, Pardi MB, Löhr H, Siegel N, Hammerschmidt M, Marin-Burgin A and Lanuza GM.  Cell Reports, 28: 2264-2274 (2019). *equal contribution    Full text

Whispering neurons fuel cortical highways (Perspective). Schinder AF and Lanuza GM. Science 360: 265-266 (2018).  Full Text  PubMed

Delineating the Diversity of Spinal Interneurons in Locomotor Circuits. Gosgnach S, Bikoff JB, Dougherty KJ, El Manira A, Lanuza GM, Zhang Y. J Neurosci. 37: 10835-10841 (2017).  Full text    PubMed

DEVELOP_2015_129254 small   The late and dual origin of cerebrospinal fluid-contacting neurons in the mouse spinal cord.  Petracca YL*, Sartoretti MM*, Di Bella DY, Marin Burgin A, Carcagno A, Schinder AF, and Lanuza GM. Development 143: 880-891 (2016).  Full Text  PubMed

Sim1 is required for the migration and axonal projections of V3 interneurons in the developing mouse spinal cord. Blacklaws J, Deska-Gauthier D, Jones DT, Petracca YL, Fawcett J, Glover JC, Lanuza GM and Zhang Y.  Dev.Neurobiol.   75:1003-1017 (2015). Full Text  PubMed

home_cover Neurogenin3 restricts serotonergic neuron differentiation to the hindbrain. Carcagno AL*, Di Bella DJ*, Goulding M, Guillemot F and Lanuza GM. J.Neurosci  34: 15223-15233 (2014).  Full Text  PubMed  

Delayed coupling to feedback inhibition during a critical period for the integration of adult-born granule cells. Temprana SG, Mongiat LA, Yang SM, Trinchero MF, Alvarez D, Kropff E, Giacomini D, Beltramone N, Lanuza GM, Schinder AF.  Neuron 85: 116-130 (2015). Full Text PubMed  

V1 and v2b interneurons secure the alternating flexor-extensor motor activity mice require for limbed locomotion. Lanuza GM*, Zhang J*, Britz O, Wang Z, Siembab V, Zhang Y, Velasquez T, Alvarez F, Frank T and Goulding M. *equal contribution.   Neuron  82: 138-150 (2014). Full text PubMed

Functional characterization of dI interneurons in the neonatal mouse spinal cord. Dyck J, Lanuza GM and Gosgnach S. J.Neurophysiol. 107: 3256-3266 (2012).   PubMed

Isl1 Is Required For Multiple Aspects of Motor Neuron Development. Liang M, Song MR, Xu ZG, Lanuza GM, Liu Y, Zhuang T, Chen Y, Pfaff S, Evans SM, Sun Y. Mol.Cell.Neurosci. 47:215-222 (2011).   PubMed

Identification of distinct telencephalic progenitor pools for excitatory and inhibitory cell diversity in the amygdala. Hirata T, Cocas L, Lanuza GM, Li P, Huntsman M and Corbin JG.  Nature Neurosci.  12: 141-149 (2009).    PubMed

V3 spinal neurons establish a robust and balanced locomotor rhythm during walking. Zhang Y, Narayan S, Geiman E, Lanuza GM, Velasquez, Shanks B, T, Akay T, Dyck J, Pearson K, Gosgnach S, Fan C-M and Goulding M. Neuron 60: 84-96  (2008).   PubMed

V1 spinal neurons regulate the speed of vertebrate locomotor outputs. Lanuza GM*, Gosgnach S*, Butt SJB, Saueressig H, Zhang Y, Velazquez T, Riethmacher D, Callaway E, Kiehn O and Goulding M.    *equal contribution.   Nature 440: 215-219  (2006).   PubMed

Gsh2 is required for the repression of Ngn1 in specification of dorsal interneuron fate in the spinal cord. Kriks S, Lanuza GM, Mizuguchi R, Nakafuku M and Goulding M. Development 132: 2991-3002 (2005).    PubMed

Genetic identification of spinal interneurons that coordinate left-right locomotor activity necessary for walking movements.  Lanuza GM*, Gosgnach S*, PieraniA, JessellT and Goulding M.   *co-author.  Neuron 42: 375-386 (2004).    PubMed

The formation of sensorimotor circuits.  Goulding M, Lanuza G, Sapir T and Narayan S. Curr.Opin.Neurobiol. 12:508-515 (2002).    PubMed

Dimeric inhibin production are differentially regulated by hormones and local factors in granulosa cells. Lanuza GM, Groome NP, Barañao JL and Campo S. Endocrinology 140: 2549-2554 (1999).    PubMed

Growth promoting activity of oocytes on granulosa cells is decreased upon meiotic maturation. Lanuza GM, Fischman ML and Barañao JL. Dev.Biol. 197: 129-139 (1998).    PubMed

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Guillermo Lanuza
Jefe de Laboratorio - glanuza@leloir.org.ar



Abel Carcagno
Investigador Asociado - acarcagno@leloir.org.ar



Luciano Brum
Becario Doctoral - lbrum@leloir.org.ar



Carla Campetella
Becaria Doctoral - ccampetella@leloir.org.ar



Nicole Siegel
Estudiante - nsiegel@leloir.org.ar



Joselina Berti
Estudiante - jberti@leloir.org.ar



Santiago Olszevicki
Estudiante



Daniela Di Bella
ALUMNI. Becaria Doctoral - ddibella@leloir.org.ar



María Micaela Sartoretti
ALUMNI. Becaria Doctoral



Yanina Petracca
ALUMNI. Becaria Doctoral



Cristina Monzon
ALUMNI. Pasante



María Lucía Bartolomeu
Alumni Becaria