Induction of c-Jun immunoreactivity in spinal cord and brainstem neurons in a transgenic mouse model for amyotrophic lateral sclerosis

Abstract

Transgenic mice carrying amyotrophic lateral sclerosis (ALS)-linked superoxide dismutase 1 (SOD1) mutations develop a motoneuron disease resembling human ALS. c-Jun is a transcription factor frequently induced in injured neurons. In this study we have examined the distribution of c-Jun-immunoreactivity in the brainstem and spinal cord of transgenic SOD1 mice with a glycine 93 alanine (G93A) mutation. In non-transgenic littermates c-Jun immunostaining was predominantly situated in motoneurons. The number of c-Jun immunoreactive motoneuron was reduced in SOD1(G93A) mice due to pronounced loss of motoneurons. In SOD1(G93A) mice, however, c-Jun-immunoreactivity was strongly induced in neurons in the intermediate zone (Rexed's laminae V–VIII and X) of the spinal cord and throughout the brainstem reticular formation. These findings are of interest since increased levels of c-jun also have been found in the intermediate zone of the spinal cord of ALS patients. Thus c-Jun may be involved in the neurodegenerative processes both in ALS and in motoneuron disease in SOD1(G93A) mice.