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G Sobue

Publications and source records attributed to G Sobue.

At least 73 records · Page 4Linked to original sources
PubMed2000

Detection of triplet repeat expansion in the human genome by use of hybridization signal intensity.

Triplet repeat disease is a group of hereditary neurodegenerative disorders caused by expansion of trinucleotide repeats such as CAG/CTG, CGG/CCG, and GAA/TTC. Direct detection of the expansion in the patient's genome shortcuts the tedious process needed for identification of disease genes by conventional approaches. Here we describe a method to detect triplet repeat expansion from the hybridization signal intensity. Using a digoxigenin-labeled (CTG)9 probe, the hybridization intensity and number of repeats showed a good linear correlation. The technique detected expansion in genomic DNA in all cases with moderate or large expansion. Even in the case of a small expansion, this method could detect the mutant fragment. The technique has advantages over related techniques because it is more sensitive and can be applied to cases where a small repeat expansion is involved.

Alleles↗
PubMed2000

CREB-binding protein sequestration by expanded polyglutamine.

Spinal and bulbar muscular atrophy (SBMA) is one of eight inherited neurodegenerative diseases known to be caused by CAG repeat expansion. The expansion results in an expanded polyglutamine tract, which likely confers a novel, toxic function to the affected protein. Cell culture and transgenic mouse studies have implicated the nucleus as a site for pathogenesis, suggesting that a critical nuclear factor or process is disrupted by the polyglutamine expansion. In this report we present evidence that CREB-binding protein (CBP), a transcriptional co-activator that orchestrates nuclear response to a variety of cell signaling cascades, is incorporated into nuclear inclusions formed by polyglutamine-containing proteins in cultured cells, transgenic mice and tissue from patients with SBMA. We also show CBP incorporation into nuclear inclusions formed in a cell culture model of another polyglutamine disease, spinocerebellar ataxia type 3. We present evidence that soluble levels of CBP are reduced in cells expressing expanded polyglutamine despite increased levels of CBP mRNA. Finally, we demonstrate that over-expression of CBP rescues cells from polyglutamine-mediated toxicity in neuronal cell culture. These data support a CBP-sequestration model of polyglutamine expansion disease.

Animals↗
PubMed2000

Chaperones Hsp70 and Hsp40 suppress aggregate formation and apoptosis in cultured neuronal cells expressing truncated androgen receptor protein with expanded polyglutamine tract.

Spinal and bulbar muscular atrophy (SBMA) is one of a group of human inherited neurodegenerative diseases caused by polyglutamine expansion. We have previously demonstrated that the SBMA gene product, the androgen receptor protein, is toxic and aggregates when truncated. Heat shock proteins function as molecular chaperones, which recognize and renaturate misfolded protein (aggregate). We thus assessed the effect of a variety of chaperones in a cultured neuronal cell model of SBMA. Overexpression of chaperones reduces aggregate formation and suppresses apoptosis in a cultured neuronal cell model of SBMA to differing degrees depending on the chaperones and their combinations. Combination of Hsp70 and Hsp40 was the most effective among the chaperones in reducing aggregate formation and providing cellular protection, reflecting that Hsp70 and Hsp40 act together in chaperoning mutant and disabled proteins. Although Hdj2/Hsdj chaperone has been previously reported to suppress expanded polyglutamine tract-formed aggregate, Hsdj/Hdj2 showed little effect in our system. These findings indicate that chaperones may be one of the key factors in the developing of CAG repeat disease and suggested that increasing expression level or enhancing the function of chaperones will provide an avenue for the treatment of CAG repeat disease.

Apoptosis↗
PubMed2000

Medial temporal atrophy and memory impairment in early stage of Alzheimer's disease: an MRI volumetric and memory assessment study.

Memory impairment and medial temporal lobe (MTL) involvement are the earliest and most prominent features of Alzheimer's disease (AD). A psychological assessment of memory function and an evaluation of the morphological changes in MTL structures, as found in the mild form of AD, are important for early diagnosis as well as for understanding the pathophysiology of the disease. In the present study, we aimed to evaluate correlations in these psychoanatomical changes in terms of the stage of AD. We performed MRI-based volumetric measurements of the MTL structure and neuropsychological tests, using MMSE and the Wechsler memory scale-revised (WMS-R), on 27 elderly normal subjects and 46 probable AD patients, and then checked for possible correlations between the volumetric measurements and memory dysfunction. The severity of the AD patients' condition was assessed by CDR scale. Each MTL structure decreased in volume with increasing severity of AD. In very early AD, the reduction in the amygdala volume was pronounced, while the hippocampal volumes were relatively unchanged. Neuropsychological scores also declined with increasing severity of AD. Scores on the main WMS-R subsets examined (verbal memory, visual memory, and delayed recall) decreased significantly in the very mild group, as compared with normal controls. The WMS-R test scores correlated significantly with the amygdala volumes in normal control subjects and very mild AD patients. Our findings suggest that MRI-based amygdaloid volumetric measurement provides a sensitive marker, and that the degeneration of the amygdala may begin very early in the course of AD.

Aged↗
PubMed2000

Expression of HLA-DR and its enhancing molecules in muscle fibers in polymyositis.

Polymyositis (PM) is an autoimmune inflammatory muscle disease of unknown cause in which cellular immunity is thought to play an important pathogenic role. Class II major histocompatibility complex (class II MHC: human leukocyte antigen (HLA)-DR operates as a cofactor of antigen presentation in immunological responses. There has been a major debate over whether muscle fibers themselves synthesize and express HLA-DR molecules and play a role in antigen presentation in PM pathogenesis. In this study, we demonstrated that most muscle fibers from patients with PM synthesized and expressed HLA-DR molecules on their surface. Human leukocyte antigen-DR expression was highly specific to PM. In addition, class II transactivator (CIITA), human leukocyte antigen DM (HLA-DM), and invariant chain (Ii), which are indispensable for expression of mature HLA-DR molecules and for antigen processing and presentation, were co-expressed. One of the cytokines that could induce this expression is interferon-gamma (IFN-gamma), released by activated lymphocytes. Our results indicate that in PM muscle fibers synthesize and express HLA-DR molecules and may contribute to the inflammatory responses together with lymphocytes.

Adult↗
PubMed2000

Intrafamilial phenotypic variation in limb-girdle muscular dystrophy type 2C with compound heterozygous mutations.

Two Japanese-Brazilian siblings with type 2C limb girdle muscular dystrophy showed a maternal 521-T deletion in exon 6 and a larger paternal deletion of exon 6 in the gamma-sarcoglycan gene. One sib was ambulant at 29 years of age, whereas the other sib was confined to a wheelchair at the age of 12. Sarcoglycan staining of the muscle was reduced in both siblings but it did not correlate with the observed variability of the clinical severity.

Adult↗
PubMed2000

Reduced expression of DMAHP/SIX5 gene in myotonic dystrophy muscle.

In myotonic dystrophy (DM), the expansion of CTG triplet repeats in the 3'-untranslated region of DM-protein kinase (DMPK) is a causal gene mutation. However, the pathogenic molecular mechanism of CTG repeat expansion for DM phenotypic expression is unclear. To investigate this issue, we examined the influence of CTG repeat expansion on the expression levels of DMPK gene and 3'-flanking DM locus-associated homeodomain protein (DMAHP)/SIX5 gene in the muscles of DM patients. We isolated RNA from muscle tissues of six DM patients and six controls, and performed a competitive reverse transcriptional polymerase chain reaction (RT-PCR) assay. The total mRNA level of DMAHP/SIX5 was significantly lower in DM than in controls, but the DMPK mRNA level was unchanged. Our results suggest that CTG repeat expansion influences the expression of genes other than DMPK to cause the DM phenotype.

Adult↗
PubMed2000

Mutations in the peripheral myelin protein zero and connexin32 genes detected by non-isotopic RNase cleavage assay and their phenotypes in Japanese patients with Charcot-Marie-Tooth disease.

Mutations of myelin protein zero (MPZ) and connexin32 (Cx32) genes were examined in 70 unrelated Japanese patients with Charcot-Marie-Tooth disease (CMT) without PMP22 gene duplication. A new method, which could detect base pair mismatches with Rnase cleavage on agarose gel electrophoresis, identified 5 and 4 mutations of the MPZ and Cx32 genes, respectively, including one novel mutation (Ser128Ter) of Cx32. This non-isotopic RNase cleavage assay (NIRCA) employed in the present study is very suitable for exploring mutations of MPZ and Cx32 genes in a large number of CMT patients, as the phenotype of patients with CMT is greatly divergent from demyelinating to axonal pathology.

Adolescent↗
PubMed2000

Brainstem-type Lewy body disease presenting with progressive autonomic failure and lethargy.

The authors report an autopsy case characterized by progressive lethargy and autonomic failure with a distinctive pattern of occurrence of Lewy bodies. Autonomic dysfunction such as sleep apnea, orthostatic hypotension, dysuria, and hypohidrosis predominated with lethargy, whereas parkinsonism was not apparent. Numerous Lewy bodies were widely evident microscopically in brainstem nuclei and the intermediolateral cell columns of the spinal cord, as well as in the sympathetic ganglia, but were rare or absent in the cerebral cortex and other supratentorial structures. Marked neuronal loss was seen in the locus ceruleus, raphe nuclei, dorsal vagal nuclei, and intermediolateral cell columns, but neurons in the substantia nigra, other brain regions, and sympathetic ganglia appeared undiminished. This case represents a specific clinicopathologic form of Lewy body disease occurring predominantly in the brainstem, spinal cord, and sympathetic ganglia.

Autonomic Nervous System↗
PubMed2000

The role of lymphotoxin in pathogenesis of polymyositis.

Polymyositis (PM) is a cell-mediated autoimmune disease. Perforin (PF), Fas ligand (FasL) and TNF-alpha are considered to be important factors in cytotoxic T lymphocyte-mediated cell injury, and several studies have established a role of lymphotoxin (LT) in T helper type 1 (Th1)-induced cell-mediated autoimmune diseases. In the present study, to determine how LT, PF and FasL are involved in the pathogenesis of PM, we used immunohistochemical staining (IHC), reverse transcription polymerase chain reaction (RT-PCR), and in situ hybridization (ISH) on muscle specimens from patients with PM, amyotrophic lateral sclerosis (ALS), myotonic dystrophy (MyD) and controls (NC). There were many mononuclear cells (MNCs) immunoreactive for LT and some for PF and FasL within the fasciculus in PM muscles. On the other hand, only few or no LT-, PF- and FasL-positive cells were detected in MyD, ALS and NC muscles. The results of mRNA expression of these three molecules with RT-PCR were consistent with those using IHC methods. The number of MNCs positive for LT with ISH was far higher in PM compared to MyD, ALS and NC (P < 0.05 or 0.01). The MNCs located in the connective tissue or in the vicinity of necrotizing or non-necrotizing muscles were mainly LT mRNA and CD4 positive, while MNCs invading the non-necrotic fibers were mainly LT mRNA and CD8 positive. Our results indicated that the expression of LT was up-regulated in PM, and LT plays an important role in muscle injury and orchestrating the inflammatory reaction in PM.

Aged↗
PubMed2000

Tumor necrosis factor-alpha expression in muscles of polymyositis and dermatomyositis.

We evaluated the expression of tumor necrosis factor-alpha (TNF-alpha) mRNA in muscle biopsy specimens from patients with polymyositis (PM) and dermatomyositis (DM) to clarify its role in the pathogenesis of PM and DM. We performed non-radioactive in situ hybridization studies for TNF-alpha combined with immunohistochemistry for cell type-specific markers on muscles from ten PM and five DM patients. TNF-alpha-positive infiltrating cells present in the endomysium and perimysium were found in all PM and DM muscles. The frequency of TNF-alpha-positive cells against total infiltrating cells was similar among PM and DM (27.1 +/- 7.4% in PM and 28.5 +/- 13.6% in DM). However, TNF-alpha/CD8-positive lymphocytes and TNF-alpha-positive macrophages invading the non-necrotic muscle fiber were observed only in PM but not in DM. TNF-alpha was more highly expressed in PM and DM than was previously thought, and it was suggested that TNF-alpha plays a role in muscle fiber degeneration in PM.

Aged↗
PubMed2000

Differential response to corticosteroid therapy of MRI findings and clinical manifestations in spinal cord sarcoidosis.

Spinal cord sarcoidosis is a rare disorder whose natural history and therapeutic outcome are not fully known. We examined four patients with spinal cord sarcoidosis both clinically and radiologically, particularly in relation to corticosteroid treatment. The initial manifestation was cervical myelopathy in three and uveitis in one. All four patients progressed slowly until corticosteroid therapy was initiated. The cervical spine was involved in all patients. Magnetic resonance imaging (MRI) who showed spinal cord swelling with T2-weighted high intensity and linear leptomeningeal and patchy or diffuse intramedullary enhancement with gadolinium diethylene triamine-pentaacetic acid. With corticosteroid therapy, dramatic improvement was seen on MRI, including disappearance or marked reduction of swelling and enhancement. Plasma levels of angiotensin-converting enzyme (ACE) were also markedly improved. In contrast, the clinical symptoms were little improved in one patient, unchanged in two, and rather worsened in one patient. Recurrence was seen on MRI at the maintenance dose in all four patients, without any dramatic change in clinical manifestation. MRI findings and plasma ACE are well correlated with active lesion of the spinal cord sarcoidosis, providing a useful marker for recurrence, but do not parallel the clinical manifestations.

Adrenal Cortex Hormones↗
PubMed2000

Differential somatic CAG repeat instability in variable brain cell lineage in dentatorubral pallidoluysian atrophy (DRPLA): a laser-captured microdissection (LCM)-based analysis.

Employing a laser-captured microdissection (LCM), we have investigated the somatic instability of CAG repeats in the variable brain cell lineage in three patients with dentatorubral pallidoluysian atrophy (DRPLA). LCM enables the isolation of single lineage brain cells for subsequent molecular analysis. We have found that CAG repeat size and the range of CAG repeats in the cerebellar granular cells is smaller than those in cerebellar glial cells. Similarly, those in the cerebral neuronal cells are significantly shorter than those in cerebral glial cells. These data directly indicate that the CAG repeat is relatively more stable in neuronal cells than in glial cells. Furthermore, cerebellar granular cells show significantly smaller main CAG repeat size and CAG repeat range than either Purkinje cells or cerebral neuronal cells, suggesting that somatic instability in the CAG repeat is markedly variable even among the different types of neuronal populations. The cell-specific CAG repeat instability may thus be more complex than has previously been considered. LCM is a powerful tool for elucidating the mechanism of the triplet repeat instability of each cell type.

Adult↗
PubMed2000

Decreased phosphorylation levels of TrkB neurotrophin receptor in the spinal cords from patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is characterized by the selective degeneration of specific populations of cranial and spinal motor neurons. In this study, we examined the expression of the high affinity functional receptor for BDNF, TrkB, and assessed the functional state of TrkB by examining the level of phosphorylation on tyrosine residues in ALS spinal cords. The data showed that TrkB-immunoprecipitates prepared from cell-free lysates of ALS spinal cords by use of an anti-TrkB antibody contained much more TrkB protein than from controls. These TrkB proteins expressed in ALS spinal cords, however, are much less phosphorylated on tyrosine residues than those of controls. Moreover, RT-PCR analysis of TrkB mRNA in ALS spinal cords demonstrated that the expression of Trk B mRNA is also upregulated in ALS spinal cords compared with those of controls. These data strongly suggest that there exists an abnormality in TrkB-mediated intracellular signaling in ALS spinal cords and shed a light on the possibility of the therapeutic intervention by normalizing this intracellular signaling.

Amyotrophic Lateral Sclerosis↗
PubMed2000

Temporal expression of mRNAs for neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM), cardiotrophin-1 (CT-1) and their receptors (IL-11Ralpha and OSMRbeta) in peripheral nerve injury.

The mRNA expression pattern of the neuropoietic cytokines, interleukin-11 (IL-11), oncostatin M (OSM) and cardiotrophin-1 (CT-1), and their receptor components (IL-11Ralpha and OSMRbeta) was examined in peripheral nerves on two different types of injury, crush and transection. The IL-11 mRNA increased after nerve damage and immediately returned to control levels. The OSM mRNA expression increased rapidly after nerve injury and relatively high expressions were maintained for at least 14 days. The CT-1 mRNA was not expressed in any time before and after the injury. Interestingly, IL-11Ralpha was expressed in the intact nerve and decreased after injury. The expression of OSMRbeta increased slightly after the injury. Moreover, temporal mRNA expression pattern of these neuropoietic cytokines and receptors was similar between the crushed and transected models. Each neuropoietic cytokine of IL-11, OSM and CT-1 has its own specific temporal mRNA expression pattern, which is also different from those of ciliary neuro-trophic factor (CNTF), leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). These results suggest that all neuropoietic cytokines have distinctive functions in nerve degeneration and repair process in response to peripheral nerve injury.

Animals↗
PubMed2000

Sisters homozygous for the spinocerebellar ataxia type 6 (SCA6)/CACNA1A gene associated with different clinical phenotypes.

Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disease caused by a CAG repeat expansion in the CACNA1A gene. The neurodegeneration that occurs in CAG repeat diseases is considered to share a common mechanism that may result in the gain of a toxic function related to the expanded polyglutamine tracts. However, the phenotypic expression in homozygotes for CAG repeat diseases has been controversial, and is not clearly related to a gain of functional mechanism. We identified a Japanese family with two sisters who were homozygous for the SCA6 with identical CAG repeat expansion (25/25). They showed an earlier age of onset (27 years in both) than their father (44 years), a heterozygote with an expanded allele showing the same CAG repeat length as the homozygotes (25/14). Interestingly, the two sisters showed differences in disease progression and severity, although the age of onset and CAG repeat length were identical. These findings strongly suggest that the gene dosage influences the age of onset, but other unknown factors are also important in the phenotypic expression of homozygous SCA6.

Adult↗