Kinesin expression in the central nervous system of humans and transgenic hSOD1G93A mice with amyotrophic lateral sclerosis.

BACKGROUND

Amyotrophic lateral sclerosis is a fatal motor neuron degenerative disease. Most cases are sporadic (SALS), and approximately 10% are familial (FALS) among which over 20% are linked to the SOD1 mutation. Both SALS and FALS have been associated with retrograde axonal transport defects. Kinesins (KIFs) are motor proteins involved mainly in anterograde transport; however, some also participate in retrograde transport.

OBJECTIVE

The purpose of the study was to investigate and compare the expression of kinesins involved in anterograde (KIF5A, 5C) and retrograde (KIFC3/C2) axonal transport in SALS in humans and FALS in mice with the hSOD1G93A mutation.

METHODS

The studies were conducted on various parts of the CNS from autopsy specimens of SALS patients, and transgenic mice at presymptomatic and symptomatic stages using real-time quantitative PCR and reverse-transcription PCR.

RESULTS

All KIF expression in the motor cortex of individual SALS subjects was higher than in the adjacent sensory cortex, in contrast to the expression in control brains. It was also significantly higher in the frontal cortex of symptomatic but not presymptomatic mice compared to wild-type controls. However, the mean KIF expression in the SALS motor and sensory cortexes was lower than in control cortexes. To a lesser extent the decrease in KIF mean expression also occurred in human but not in mouse ALS spinal cords and in both human and mouse cerebella.

CONCLUSION

Disturbances in kinesin expression in the CNS may dysregulate both anterograde and retrograde axonal transports leading to motor neuron degeneration.