title: Endogenous cerebellar neurogenesis in adult mice with progressive ataxia.
abstract: OBJECTIVE
  Transplanting exogenous neuronal progenitors to replace damaged neurons in the adult brain following injury or neurodegenerative disorders and achieve functional amelioration is a realistic goal. However, studies so far have rarely taken into consideration the preexisting inflammation triggered by the disease process that could hamper the effectiveness of transplanted cells. Here, we examined the fate and long-term consequences of human cerebellar granule neuron precursors (GNP) transplanted into the cerebellum of Harlequin mice, an adult model of progressive cerebellar degeneration with early-onset microgliosis.
  
  
  METHODS
  Human embryonic stem cell-derived progenitors expressing Atoh1, a transcription factor key to GNP specification, were generated in vitro and stereotaxically transplanted into the cerebellum of preataxic Harlequin mice. The histological and functional impact of these transplants was followed using immunolabeling and Rotarod analysis.
  
  
  RESULTS
  Although transplanted GNPs did not survive beyond a few weeks, they triggered the proliferation of endogenous nestin-positive precursors in the leptomeninges that crossed the molecular layer and differentiated into mature neurons. These phenomena were accompanied by the preservation of the granule and Purkinje cell layers and delayed ataxic changes. In vitro neurosphere generation confirmed the enhanced neurogenic potential of the cerebellar leptomeninges of Harlequin mice transplanted with exogenous GNPs.
  
  
  CONCLUSIONS
  The cerebellar leptomeninges of adult mice contain an endogenous neurogenic niche that can be stimulated to yield mature neurons from an as-yet unidentified population of progenitors. The transplantation of human GNPs not only stimulates this neurogenesis, but, despite the potentially hostile environment, leads to neuroprotection and functional amelioration.
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Csaba
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France ; School of Physiology and Pharmacology, MRC Centre for Synaptic Plasticity Bristol, United Kingdom.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Peineau
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France ; National Brain Research Centre Manesar, India.
authors.forename: Rupali
authors.initials: R
authors.lastname: Srivastava
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France.
authors.forename: Sowmyalakshmi
authors.initials: S
authors.lastname: Rasika
authors.affiliation: Centre for Neuroscience, IISC Bangalore, India.
authors.forename: Shyamala
authors.initials: S
authors.lastname: Mani
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France ; Department of Division of Imaging Sciences and Biomedical Engineering, Centre for the Developing Brain, King's College London, King's Health Partners, St. Thomas' Hospital London, United Kingdom.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gressens
authors.affiliation: Inserm U1141 Paris, France ; Sorbonne Paris Cité, Université Paris Diderot, UMRS 1141 Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: El Ghouzzi