The causative pathomechanism of sporadic amyotrophic lateral sclerosis (ALS) is not clearly understood. Using microarray technology combined with laser-captured microdissection, gene expression profiles of degenerating spinal motor neurons isolated from autopsied patients with sporadic ALS were examined. Gene expression was quantitatively assessed by real-time reverse transcription polymerase chain reaction and in situ hybridization. Spinal motor neurons showed a distinct gene expression profile from the whole spinal ventral horn. Three percent of genes examined were downregulated, and 1% were upregulated in motor neurons. Downregulated genes included those associated with cytoskeleton/axonal transport, transcription, and cell surface antigens/receptors, such as dynactin, microtubule-associated proteins, and early growth response 3 (EGR3). In contrast, cell death-associated genes were mostly upregulated. Promoters for cell death pathway, death receptor 5, cyclins A1 and C, and caspases-1, -3, and -9, were upregulated, whereas cell death inhibitors, acetyl-CoA transporter, and NF-kappaB were also upregulated. Moreover, neuroprotective neurotrophic factors such as ciliary neurotrophic factor (CNTF), Hepatocyte growth factor (HGF), and glial cell line-derived neurotrophic factor were upregulated. Inflammation-related genes, such as those belonging to the cytokine family, were not, however, significantly upregulated in either motor neurons or ventral horns. The motor neuron-specific gene expression profile in sporadic ALS can provide direct information on the genes leading to neurodegeneration and neuronal death and are helpful for developing new therapeutic strategies.
Spinal and bulbar muscular atrophy (SBMA) is an inherited neurodegenerative disorder caused by the expansion of the polyglutamine (polyQ) tract of the androgen receptor (AR-polyQ). Characteristics of SBMA include proximal muscular atrophy, weakness, contraction fasciculation and bulbar involvement. MicroRNAs (miRNAs) are a diverse class of highly conserved small RNA molecules that function as crucial regulators of gene expression in animals and plants. Recent functional studies have shown the potent activity of specific miRNAs as disease modifiers both in vitro and in vivo. Thus, potential therapeutic approaches that target the miRNA processing pathway have recently attracted attention. Here we describe a novel therapeutic approach using the adeno-associated virus (AAV) vector–mediated delivery of a specific miRNA for SBMA. We found that miR-196a enhanced the decay of the AR mRNA by silencing CUGBP, Elav-like family member 2 (CELF2). CELF2 directly acted on AR mRNA and enhanced the stability of AR mRNA. Furthermore, we found that the early intervention of miR-196a delivered by an AAV vector ameliorated the SBMA phenotypes in a mouse model. Our results establish the proof of principle that disease-specific miRNA delivery could be useful in neurodegenerative diseases.
We studied intracellular localization of the UL31 protein of herpes simplex virus type 2 (HSV-2) in infected and transfected cells. The UL31 protein localized diffusely throughout the nucleus in infected Vero cells and the distribution patterns of the UL31 protein appeared to be different from those of either replication protein ICP8 or capsid protein ICP35. In transfected Vero cells it localized diffusely throughout the nucleus except the nucleolus at early times after transfection. At very low efficiency, it accumulated in the nucleolus. At intermediate times after transfection, the UL31 protein showed punctate staining in the nucleus. These punctate forms fused and became larger. At later times after transfection, granular forms further fused and a nuclear diffuse pattern virtually disappeared. We also constructed five N and C terminal deletion mutants of the UL31 protein for transfection assays and showed that the region containing amino acids 44 to 110 was important for nuclear and nucleolar localization. Moreover, green fluorescent protein (GFP)-targeting experiments showed that the UL31 protein was able to transport nonnuclear GFP to the nucleus and nucleolus as a fusion protein.
We have identified the herpes simplex virus type 1 (HSV-1) US10 gene product using rabbit polyclonal antisera raised against a recombinant 6xHis-US10 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with 34 and 36 kDa proteins in HSV-1 KOS-infected cells as shown by Western blotting and immunoprecipitation experiments. The 36 kDa protein was immunoprecipitated with the US10 antiserum from 32 P-labelled lysates of Vero cells infected with HSV-1 KOS, demonstrating that the US10 protein was phosphorylated. Indirect immunofluorescence studies
In a differential gene expression profile, we showed previously that dynactin 1 (DCTN1), early growth response 3 (EGR3), acetyl-CoA transporter (ACATN), death receptor 5 (DR5), and cyclin C (CCNC) were prominently up- or downregulated in motor neurons of sporadic amyotrophic lateral sclerosis (ALS). In the present study, we examined the correlation between the expression levels of these genes and the levels of pathologic markers for motor neuron degeneration (i.e. cytoplasmic accumulation of phosphorylated neurofilament H [pNF-H] and ubiquitylated protein) and the numbers of residual motor neurons in 20 autopsies of patients with sporadic ALS. DCTN1 and EGR3 were widely downregulated, and the changes in gene expression were correlated to the number of residual motor neurons. In particular, DCTN1 was markedly downregulated in most residual motor neurons before the accumulation of pNF-H, even in cases with well-preserved motor neuron populations. ACATN, DR5, and CCNC were upregulated in subpopulations of residual motor neurons, and their expression levels were well correlated with the levels of pNF-H accumulation and the number of residual motor neurons. The expressions of DCTN1, EGR3, ACATN, and DR5 were all markedly altered before ubiquitylated protein accumulation. DCTN1 downregulation appears to be an early event before the appearance of neurodegeneration markers, whereas upregulations of DR5 and CCNC are relatively later phenomena associated with pathologic markers and leading to neuronal death. The sequence of motor neuron-specific gene expression changes in sporadic ALS can be beneficial information in developing appropriate therapeutic strategies for neurodegeneration.
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