Séminaire de Anne Kastner (Spicci)

Vendredi 5 septembre 2025, à 11h, Salle Henri Gastaut, INT

Anne Kastner from the ‘Spicci Team’ (Institut de Neurosciences de la Timone)

Characterisation of the spinal cord central canal region: species comparison and reaction to injury

Abstract: The cerebrospinal fluid (CSF) is a major transmitter of physiopathological signals that may control the body state and behavior. In the spinal cord (SC), this fluid transit within the central canal (cc), mainly composed of ependymal cells but also of CSF- contacting neurons (CSF-cNs) which may sense various CSF parameters. To assess the role of the cc region as a CSF-spinal interface, we compare its organization between rodents and various primates, and we analyse its reaction to injury. In macaca Rhesus monkey, we show that the cc is surrounded by a large hyponeural peri-ependymal zone containing only CSF-cNs and enriched with astrocytes and microglia cells. Such specific organization was also observed in capuchin, chimpanzee and humans but not in rodents and marmoset, suggesting an evolutive specialization and enlargement of this CSF-SC barrier. We assess also the role of this cc region as a regulatory CSF-spinal interface by analysing its response to SC injury. We show first that SC injury (lateral section at C2 level in rodents) but also to a lesser extent sham surgical injury led to a transient neuroinflammatory response characterized by CSF inflammatory cytokines induction, IBA-1+ microglia reaction around the cc (at C4 level) and neural activation in NTS & AP region. SC injury led moreover to a cc enlargement (at C1, 7DPI). A transient cell activation (c-Fos induction) was observed in ependyma cells 1H and 1D after SC injury but also in CSF-cNs (both after sham and SC injury and also in vitro model), suggesting that cc cell activation may be part of the neuroinflammatory response that occurred after SC and sham injury. Altogether, our data suggest that the cc region may constitute a regulatory zone between the cc CSF and the spinal parenchyma that may sense and respond to CSF inflammatory signals.