Cerebrospinal fluid-contacting neurons: multimodal cells with diverse roles in the CNS
Claire Wyart, Martin Carbó-Tano, Yasmine Cantaut-Belarif, Adeline Orts-Del’Immagine, Urs L. Böhm
Abstract
The cerebrospinal fluid (CSF) is a complex solution that circulates around the CNS, and whose composition changes as a function of an animal’s physiological state. Ciliated neurons that are bathed in the CSF — and thus referred to as CSF-contacting neurons (CSF-cNs) — are unusual polymodal interoceptive neurons. As chemoreceptors, CSF-cNs respond to variations in pH and osmolarity and to bacterial metabolites in the CSF. Their activation during infections of the CNS results in secretion of compounds to enhance host survival. As mechanosensory neurons, CSF-cNs operate together with an extracellular proteinaceous polymer known as the Reissner fibre to detect compression during spinal curvature. Once activated, CSF-cNs inhibit motor neurons, premotor excitatory neurons and command neurons to enhance movement speed and stabilize posture. At longer timescales, CSF-cNs instruct morphogenesis throughout life via the release of neuropeptides that act over long distances on skeletal muscle. Finally, recent evidence suggests that mouse CSF-cNs may act as neural stem cells in the spinal cord, inspiring new paths of investigation for repair after injury. Ciliated neurons sited at the interface between the CNS and the cerebrospinal fluid (CSF) are present in many species; however, it is only in recent years that these ‘CSF-contacting neurons’ have been investigated in detail. Wyart et al. here discuss the features of these neurons and our current understanding of their varied contributions to CNS function.