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Spinal and bulbar muscular atrophy (SBMA) is a polyglutamine disease caused by the expansion of a CAG repeat in the androgen receptor (AR) gene. We generated a transgenic mouse model carrying a full-length AR containing 97 CAGs. Three of the five lines showed progressive muscular atrophy and weakness as well as diffuse nuclear staining and nuclear inclusions consisting of the mutant AR. These phenotypes were markedly pronounced in male transgenic mice, and dramatically rescued by castration. Female transgenic mice showed only a few manifestations that markedly deteriorated with testosterone administration. Nuclear translocation of the mutant AR by testosterone contributed to the phenotypic difference with gender and the effects of hormonal interventions. These results suggest the therapeutic potential of hormonal intervention for SBMA.

Familial amyotrophic lateral sclerosis (FALS)-linked mutations in copper-zinc superoxide dismutase (SOD1) cause motor neuron death through one or more acquired toxic properties. We analyzed the molecular mechanism underlying motor neuron degeneration in the transgenic mouse model expressing the SOD1 gene with G93A mutation. Using cDNA microarray, the differentially expressed genes were identified in the spinal cords of G93A mice, 30 being elevated and seven decreased. cDNA microarray analysis to monitor gene expression during neurodegeneration revealed an up-regulation of genes related to an inflammatory process, such as the tumor necrosis factor-alpha (TNF-alpha) gene, resulting from glial cell activation, together with the change in apoptosis-related gene expression, such as caspase-1. The increased expression of the inflammation- and apoptosis-related genes occurred at 11 weeks of age in the presymptomatic stage prior to motor neuron death. These results suggest a mechanism of neurodegeneration that includes an inflammatory response as an important component. Thus, ALS has paralleled other neurodegenerative disorders, such as Alzheimer's and prion diseases, in which the inflammatory process is believed to participate directly in neuronal death.

Although more than 130 years have gone by since the first description in 1869 by Jean-Martin Charcot, the mechanism underlying the characteristic selective motor neuron degeneration in amyotrophic lateral sclerosis (ALS) has remained elusive. Modest advances in this research field have been achieved by the identification of copper/zinc superoxide dismutase 1 (SOD1) as one of the causative genes for rare familial ALS (FALS) and by the development and analysis of mutant SOD1 transgenic mouse models. However, in sporadic ALS (SALS) with many more patients, causative or critical genes situated upstream of the disease pathway have not yet been elucidated and no available disease models have been established. To approach genes causative or critical for ALS, gene expression profiling in tissues primarily affected by the disease has represented an attractive research strategy. We have been working on screening these genes employing and combining several new technologies such as cDNA microarray, molecular indexing, and laser capture microdissection. Many of the resultant genes are of intense interest and may provide a powerful tool for determining the molecular mechanisms of ALS. However, we have barely arrived at the starting point and are confronting an enormous number of genes whose roles remain undetermined. Challenging tasks lie ahead of us such as identifying which genes are really causative for ALS and developing a disease model of SALS with due consideration for the expression changes in those genes. [ABSTRACT FROM AUTHOR]

Presents a study which reported that overexpression of the inducible form of human HSP70 markedly ameliorated clinical and pathological phenotypes, and that this amelioration was correlated with the reduction of nuclear-localized mutant androgen receptor (AR) protein complexes in the mouse model of spinal and bulbar muscular atrophy. Materials and methods; Nondeleterious effects of HSP70 overexpression and generation of double-transgenic mice; Colocalization of HSP70 with mutant AR in the nuclei.

To analyze the genes related to the pathophysiology of sporadic amyotrophic lateral sclerosis (SALS) we performed gene profiling of SALS spinal cords using molecular indexing combined with cDNA microarray. Eighty-four fragments were cloned in the first screening procedure with molecular indexing. Subsequent quantitative microarray screening revealed 11 genes which were differentially expressed in SALS. Real-time RT-PCR verified that the expression level of the following six genes was altered in SALS: dorfin, metallothionein-3, 30 kDa TATA-binding protein-associated factor, neugrin, ubiquitin-like protein 5 and macrophage-inhibiting factor-related protein-8. These results indicated that genes associated with the ubiquitin–proteasome system, oxidative toxicity, transcription, neuronal differentiation and inflammation might be involved in the pathogenesis of SALS. [Copyright &y& Elsevier]