The Golgi apparatus is fragmented in spinal cord motor neurons of amyotrophic lateral sclerosis with basophilic inclusions

The mechanisms of neuronal death in amyotrophic lateral sclerosis (ALS) are not known. A pathological aggregation of cytoplasmic constituents in the form of variety of inclusions may play a role in the pathogenesis of neuronal death. Cytoplasmic basophilic inclusions (BIs) in motor neurons are commonly found in sporadic juvenile ALS. The functional significance of these inclusions is not known, i.e., whether they represent a protective reaction for the isolation of abnormal products from the cytoplasm, or a sign of irreversible neuronal damage. To gain insights on the significance of BIs we asked whether neurons with BIs had an intact or fragmented Golgi apparatus (GA), a sign of neuronal degeneration reported not only in sporadic and familial ALS with mutations of the Cu/Zn superoxide dismutase gene (SOD1), but also in transgenic mice expressing the G93A mutation of SOD1. In these mice fragmentation of the GA of spinal cord motor neurons was found months before the onset of paralysis. We report here that all neurons bearing the inclusions showed fragmentation and reduced number of GA. These results suggest that common pathogenetic mechanisms are involved in the production of BIs and in the fragmentation of the GA.