SCAN:Study of Golgi morphology/dynamics in cell models of Amyotrophic Lateral Sclerosis

Abstract:

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease. Some familial ALS cases result from mutations in human superoxide dismutase 1 (SOD1). Golgi apparatus (GA) has been reported to appear disrupted in motor neurons (MN) from tissues of ALS patients and mouse models. These alterations could have consequences to the function of the secretory pathway of MN. There has also been evidence for secretion of SOD1 by an unknown mechanism that might involve a vesicle dependent pathway. Protein aggregates containing mutant SOD1 are another hallmark of the disease.

In this work, mouse NSC-34 cell lines, which have characteristics of MN, stably overexpressing human mutant SOD1G93A have been constructed as an ALS cell model. The effects of mutant SOD1 on GA morphology, cell apoptosis and secreted levels of secretory -Trace protein were studied. Increased GA disruption in cells expressing mutant SOD1, not related with apoptosis, was found. Furthermore, a decreased level of -Trace protein produced from mutant SOD1 expressing cells was observed.

On the other hand, mutant SOD1 was found to be secreted in association with exosomes. These secreted microvesicles might constitute a way of cell-to-cell communication and transfer of mutant toxicity.

Furthermore, NSC-34 cells transiently transfected with mutant hSOD1G93A showed prominent aggregates of mutant protein as observed by fluorescence microscopy.

In conclusion, several pathological features of ALS have been mimicked in NSC-34 cells overexpressing human mutant SOD1G93A. These can be useful to study mechanisms underlying the disease and to test potential therapeutic compounds.