Contrasting effects of cerebrospinal fluid from motor neuron disease patients on the survival of primary motor neurons cultured with or without glia.

Motor neuronal (MN) degeneration in motor neuron disease (MND) often starts focally before spreading to neighbouring MN populations, suggesting soluble factors may contribute to disease propagation. Whether cerebrospinal fluid (CSF) from MND patients contains such factors has been difficult to prove. We aimed to determine the effect of glia on the response of MNs to CSF from MND patients. Primary rat spinal MNs grown in mono-culture or cocultured with glia were exposed to CSF from patients (MND-CSF) or controls (Con-CSF) and survival measured by cell counting. In mono-culture both MND-CSF and Con-CSF reduced MN survival with MND-CSF reducing MN survival by less than Con-CSF. In coculture MN survival was unchanged by exposure to MND-CSF while exposure to Con-CSF improved MN survival. In separate experiments, murine MNs grown in mono-culture and stressed by growth factor withdrawal were partially rescued by the application of monocyte chemoattractant protein-1 (MCP-1), a trophic factor previously found to be elevated in MND-CSF. Our results suggest that MND-CSF may contain factors harmful to MNs as well as factors protective of MNs, the interplay of which is altered by the presence of glial cells. These preliminary results further emphasize the importance of MN environment to MN health.