Abstract: Amyotrophic lateral sclerosis (ALS) has its onset in middle age and is a progressive disorder characterized by degeneration of motor neurons of the primary motor cortex, brainstem and spinal cord. Most cases of ALS are sporadic, but about 10% are familial. Genes known to cause classic familial ALS (FALS) are superoxide dismutase 1 (SOD1), ANG encoding angiogenin, TARDP encoding transactive response (TAR) DNA-binding protein TDP-43 (ref. 4) and fused in sarcoma/translated in liposarcoma (FUS, also known as TLS). However, these genetic defects occur in only about 20-30% of cases of FALS, and most genes causing FALS are unknown. Here we show that there are mutations in the gene encoding optineurin (OPTN), earlier reported to be a causative gene of primary open-angle glaucoma (POAG), in patients with ALS. We found three types of mutation of OPTN: a homozygous deletion of exon 5, a homozygous Q398X nonsense mutation and a heterozygous E478G missense mutation within its ubiquitin-binding domain. Analysis of cell transfection showed that the nonsense and missense mutations of OPTN abolished the inhibition of activation of nuclear factor kappa B (NF-kappaB), and the E478G mutation revealed a cytoplasmic distribution different from that of the wild type or a POAG mutation. A case with the E478G mutation showed OPTN-immunoreactive cytoplasmic inclusions. Furthermore, TDP-43- or SOD1-positive inclusions of sporadic and SOD1 cases of ALS were also noticeably immunolabelled by anti-OPTN antibodies. Our findings strongly suggest that OPTN is involved in the pathogenesis of ALS. They also indicate that NF-kappaB inhibitors could be used to treat ALS and that transgenic mice bearing various mutations of OPTN will be relevant in developing new drugs for this disorder.
Abstract: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most common genetic determinant of Parkinson's disease (PD) in European-derived populations, but far less is known about LRRK2 mutations and susceptibility alleles in Asians. To address this issue, we sequenced the LRRK2 coding region in 36 patients with familial PD, then genotyped variants of interest in an additional 595 PD cases and 1,641 controls who were all of Japanese ancestry. We also performed a meta-analysis of studies on G2385R, a polymorphism previously reported to associate with PD. One pathogenic (G2019S) and one putative pathogenic (R1067Q) mutation were each observed in two patients with sporadic PD. The overall mutation frequency among patients was 0.6%. G2385R was highly associated with PD under a dominant model in our dataset (adjusted OR, 1.83; 95% CI, 1.31-2.54; P = 3.3 x 10(-4)) and similar results were seen in the meta-analysis (summary OR assuming fixed effects, 2.55; 95% CI, 2.10-3.10). G2385R represents the first consistently replicated common PD susceptibility variant in a non-European population and its effect size is substantially greater than that reported for other well-validated genetic risk factors for the disease. However, LRRK2 mutations appear to be rare among Japanese patients with PD.
Abstract: BACKGROUND: Aortic pulse wave velocity (PWV) is widely used as a noninvasive index of arterial stiffness and was used in the present study to investigate the relationship between PWV and cardiovascular mortality in the middle-aged and elderly Japanese population using a longitudinal study design. METHODS AND RESULTS: From 1988 to 2003, a total of 3,960 men (50-69 years old at baseline) who underwent medical check-ups and measurement of PWV, which was standardized for diastolic blood pressure, were recruited and divided into 4 groups according to the PWV values. The average follow-up period was 8.2 years. Mortality from all-causes and from cardiovascular disease significantly increased as PWV increased in the entire follow-up period. Multivariate-adjusted relative risks of all-cause and cardiovascular disease mortality for the highest quartile of PWV (>9.0 m/s) were 1.28 (95% confidence interval (CI) 0.97-1.68) and 1.83 (95%CI 1.02-3.29), respectively, compared with the lowest quartile (<7.5 m/s). CONCLUSIONS: An increased PWV can predict cardiovascular mortality in middle-aged and elderly Japanese men.
Abstract: TAR-DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene on chromosome 1p36.22, has been identified as the major pathological protein in abnormal inclusions in neurons and glial cells in sporadic amyotrophic lateral sclerosis (SALS), SOD1-negative familial ALS (FALS) and frontotemporal lobar dementia (FTLD). Twenty mutations of TARDBP in SOD1-negative FALS and SALS cases have been reported so far. To investigate the presence and frequency of TARDBP mutations in Japanese SOD1-negative FALS patients, we performed mutational screening of TARDBP in 30 SOD1-negative FALS patients. An N352S mutation was found in one case of FALS, but no TARDBP mutations were found in cases of SALS. It was thought that this mutation increases TDP-43 phosphorylation. This might lead to impaired nuclear cytoplasmic transport or protein-protein interaction, thereby leading to TDP-43 accumulation.
Abstract: To identify susceptibility variants for Parkinson's disease (PD), we performed a genome-wide association study (GWAS) and two replication studies in a total of 2,011 cases and 18,381 controls from Japan. We identified a new susceptibility locus on 1q32 (P = 1.52 x 10(-12)) and designated this as PARK16, and we also identified BST1 on 4p15 as a second new risk locus (P = 3.94 x 10(-9)). We also detected strong associations at SNCA on 4q22 (P = 7.35 x 10(-17)) and LRRK2 on 12q12 (P = 2.72 x 10(-8)), both of which are implicated in autosomal dominant forms of parkinsonism. By comparing results of a GWAS performed on individuals of European ancestry, we identified PARK16, SNCA and LRRK2 as shared risk loci for PD and BST1 and MAPT as loci showing population differences. Our results identify two new PD susceptibility loci, show involvement of autosomal dominant parkinsonism loci in typical PD and suggest that population differences contribute to genetic heterogeneity in PD.
Abstract: To confirm the incidence of SCA16 in Japan, we screened DNA samples from a number of patients of ataxia of unknown etiology for the substitution. We examined a total of 323 DNA samples from Japanese patients with inherited spinocerebellar ataxia. We found no 317-base pair band in the patients with ataxia of unknown etiology. It seemed that this mutation (c.4256C>T) is rare in Japanese patients with inherited spinocerebellar ataxia. Mutations in other populations should be analyzed. Pathological examinations and molecular biological examinations are needed to confirm that this mutation is a true cause of SCA16.
Abstract: Spinocerebellar ataxia type 6 (SCA6) is a common cause of dominantly inherited ataxia due to an expansion of the CAG repeat in the CACNA1A gene. Affected individuals from the same population share a common haplotype, raising the possibility that most SCA6 cases have descended from a small number of common founders across the globe. To test this hypothesis, we carried out haplotype analysis on SCA6 families from Europe, South America and the Far East, including an established de novo SCA6 expansion. A core CACNA1A disease haplotype was found in affected individuals across the globe. This was also present in the unaffected father of the de novo case, suggesting that the shared chromosome predisposes to the CAG repeat expansion at the SCA6 locus. The SCA6 expansion lies within a CpG island, which could act as a cis-acting element predisposing to repeat expansion as for other CAG/CTG repeat diseases. Polymorphic variation in this region may explain the high-risk haplotype found in SCA6 families.
Abstract: Age-related macular degeneration (AMD) is one of the leading causes of blindness among older adults in developed countries and also in Japan. Previous research suggests that AMD is etiologically a complex disease, caused by multiple genes and environmental factors. Association studies have identified that a complement factor H gene (CFH) variant is a major risk factor for AMD in Caucasians. However, we and two other groups have reported no association between CFH and AMD in the Japanese population. Recent studies have suggested that LOC387715 on chromosome 10q26 may be the second major risk loci for AMD in Caucasians. In this study, we examined the association between LOC387715 and AMD in Japanese, and our results show that polymorphism of the LOC387715 gene is associated with AMD in Japanese as well as in Caucasians. Our data show a disease odds ratio of 6.20 (95% CI: 2.87-13.40) conferred by homozygosity for risk alleles at LOC387715 compared with the non-risk genotype. A polymorphism of LOC387715 gene is associated with AMD in the Japanese population.
Abstract: CONTEXT: Identification and replication of susceptibility genes for Parkinson disease at the population level have been hampered by small studies with potential biases. Alpha-synuclein (SNCA) has been one of the most promising susceptibility genes, but large-scale studies have been lacking. OBJECTIVE: To determine whether allele-length variability in the dinucleotide repeat sequence (REP1) of the SNCA gene promoter is associated with Parkinson disease susceptibility, whether SNCA promoter haplotypes are associated with Parkinson disease, and whether REP1 variability modifies age at onset. DESIGN, SETTING, AND PARTICIPANTS: We performed a collaborative analysis of individual-level data on SNCA REP1 and flanking markers in patients with Parkinson disease and controls. Study site recruitment, data collection, and analyses were performed between April 5, 2004, and December 31, 2005. Eighteen participating sites of a global genetics consortium provided clinical data. Genotyping was performed for SNCA REP1, -770, and -116 markers at individual sites; however, each site also provided 20 DNA samples for regenotyping centrally. MAIN OUTCOME MEASURES: Measures included estimations of Hardy-Weinberg equilibrium in controls; a test of heterogeneity; analyses for association of single variants or haplotypes; and survival analyses for age at onset. RESULTS: Of the 18 sites, 11 met stringent criteria for concordance with Hardy-Weinberg equilibrium and low genotyping error rate. These 11 sites provided complete data for 2692 cases and 2652 controls. There was no heterogeneity across studies (P>.60). The SNCA REP1 alleles differed in frequency for cases and controls (P<.001). Genotypes defined by the 263 base-pair allele were associated with Parkinson disease (odds ratio, 1.43; 95% confidence interval, 1.22-1.69; P<.001 for trend). Multilocus haplotypes differed in frequency for cases and controls (global score statistic, P<.001). Two-loci haplotypes were associated with Parkinson disease only when they included REP1 as one of the loci. However, genotypes defined by REP1 alleles did not modify age at onset (P = .55). CONCLUSION: This large-scale collaborative analysis demonstrates that SNCA REP1 allele-length variability is associated with an increased risk of Parkinson disease.
Abstract: Recently, limbic encephalitis (LE) associated with Voltage-gated potassium channel antibody (VGKC-Ab) has been postulated as a new autoimmune disorder. Most previously reported cases of VGKC-Ab-associated LE were non-paraneoplastic, and reports of a paraneoplastic type are rare. Here we describe a 59-year-old woman with paraneoplastic VGKC-Ab-associated LE preceding the recurrence of invasive thymoma. There was a close temporal relationship between the clinical course and the changes of the VGKC-Ab titer. Unlike many of the non-paraneoplastic VGKC-Ab-associated LE cases, our cases showed the more extensive high intensity lesions on MRI and the absence of seizure and hyponatremia.
Abstract: We investigated a family manifesting progressive ataxia, with expanded SCA8 CTA/CTG repeats. Neuropathologically, degeneration of Purkinje, inferior olivary, and nigral neurons and periaqueductal gliosis were evident. The sites of Purkinje cell loss were occupied by fibrillary accumulations. The remaining Purkinje cells showed somatic sprouts, and intracytoplasmic 1C2-positive granular structures were recognizable. This characteristic distribution of neurodegeneration and Purkinje cell cytopathology were distinct from those of other hereditary spinocerebellar ataxias previously reported.
Abstract: PURPOSE: The aim of this study was to determine whether genetic polymorphism of complement factor H (CFH) is associated with age-related macular degeneration (AMD) in the Japanese population. METHODS: Genomic DNA was examined in a cohort of 67 Japanese patients with AMD and 107 controls. TT/TC/CC genotypes on exon 9 were screened for sequence alternation by polymerase chain reaction analysis and through sequencing. RESULTS: The mean ages +/- SD of AMD patients and control subjects were 73 +/- 8.5 years and 72 +/- 8.7 years, respectively. There was no significant difference between CFH genotypes in the AMD group (TT, 76%; TC, 19%; CC, 5%) and the control group (TT, 80%; TC, 17%; CC, 3%). The frequencies of T and C alleles were 86% and 14%, respectively, in the AMD group and 89% and 11%, respectively, in the control group. CONCLUSION: CFH gene polymorphism is not associated with AMD in the Japanese population. Moreover, the frequency of the C allele is low among the Japanese population.
Abstract: The clinical and genetic relationships between Alzheimer's disease (AD) and glaucoma remain obscure. The aim of this study was to determine the prevalence of open-angle glaucoma (OAG) in patients with AD and whether the apolipoprotein E (APOE) 4 allele is associated with AD, with or without OAG, in Japanese. The groups consisted of 172 patients with the diagnostic criteria of AD and 176 age-matched controls. Ophthalmic examinations were conducted, and genomic analysis was performed by PCR and digestion of products with an enzyme. OAG was found in 41 (23.8%) of the AD patients, which was a significantly (p = 0.0002) higher prevalence than that in the controls (9.9%). Furthermore, there was no significant difference between intraocular pressures (IOPs) in AD patients with OAG and without OAG. The percentage of AD patients who carried an APOE epsilon4 allele (29.5%) was significantly (p = 0.0007) higher than that of the controls (9.1%). However, the percentage of AD patients with OAG who carried an APOE epsilon4 allele (35.7%) was not significantly different than that of AD patients without OAG (27.7%, p = 0.42). In summary, the prevalence of OAG is high in Japanese patients with AD, suggesting that common factors other than APOE may contribute to the two diseases.
Abstract: BACKGROUND: A genome-wide association study identified 13 single-nucleotide polymorphisms (SNPs) significantly associated with Parkinson's disease. Small-scale replication studies were largely non-confirmatory, but a meta-analysis that included data from the original study could not exclude all SNP associations, leaving relevance of several markers uncertain. METHODS: Investigators from three Michael J Fox Foundation for Parkinson's Research-funded genetics consortia-comprising 14 teams-contributed DNA samples from 5526 patients with Parkinson's disease and 6682 controls, which were genotyped for the 13 SNPs. Most (88%) participants were of white, non-Hispanic descent. We assessed log-additive genetic effects using fixed and random effects models stratified by team and ethnic origin, and tested for heterogeneity across strata. A meta-analysis was undertaken that incorporated data from the original genome-wide study as well as subsequent replication studies. FINDINGS: In fixed and random-effects models no associations with any of the 13 SNPs were identified (odds ratios 0.89 to 1.09). Heterogeneity between studies and between ethnic groups was low for all SNPs. Subgroup analyses by age at study entry, ethnic origin, sex, and family history did not show any consistent associations. In our meta-analysis, no SNP showed significant association (summary odds ratios 0.95 to 1.08); there was little heterogeneity except for SNP rs7520966. INTERPRETATION: Our results do not lend support to the finding that the 13 SNPs reported in the original genome-wide association study are genetic susceptibility factors for Parkinson's disease.
Abstract: Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disorder characterized by cerebellar ataxia and intermittent axial myoclonus. Various mutations have been found in the PRKCG gene encoding protein kinase C gamma in SCA14 families. Most of those mutations have been found in exon 4 of the PRKCG gene. We performed polymerase chain reaction (PCR)-based screening to clarify the approximate morbidity rate of the disease in the Japanese SCA population. We screened exon 4 of the PRKCG gene in 882 SCA patients with undefined etiologies using denaturing high-performance liquid chromatography and subsequent direct sequencing. We found a novel C/T missense mutation with a Ser119-to-Phe substitution (S119F) in 2 patients and subsequently found that they belonged to the same family. This S119F mutation was not found in 259 control individuals. Further PCR-based analysis revealed an additional 5 members with the same mutation in this family. Cerebellar ataxia was manifested in 5 of those 7 members. The main symptom in 4 of the 5 affected members was pure cerebellar ataxia with late onset. They had no myoclonus, extrapyramidal signs, ophthalmoplegia, or intellectual disturbance, some of which were found in previously reported SCA families. One patient showed intractable epilepsy, severe walking disturbance, and trunk ataxia with early onset. The results of this study suggest that the frequency of SCA14 in the Japanese SCA population is very low.
Abstract: LRRK2 G2019S is the most common known cause of Parkinson disease (PD) in patients of European origin, but little is known about its distribution in other populations. The authors identified two of 586 Japanese patients with PD heterozygous for the mutation who shared a haplotype distinct from that observed in Europeans. This suggests that G2019S originated from separate founders in Europe and Japan and is more widely dispersed than previously recognized.
Abstract: We studied two genetic polymorphisms (240C/T and 480G/A) of the brain-derived neurotrophic factor (BDNF) gene in Japanese patients with Alzheimer's disease (AD, n = 172), Parkinson's disease (PD, n = 327), and multiple system atrophy (MSA, n = 122), as well as controls (n = 275). The distribution of the 240 C/T polymorphism was significantly different between AD patients and controls, whereas there was no difference in the genotype of the two polymorphisms between MSA and controls or between PD and controls. Our data suggest that BDNF might play a role in AD.
Abstract: We studied genetic polymorphisms in the glutathione-S-transferase-1 (GST-1) gene region and the interleukin-1beta (IL-1beta) promoter region in patients with Parkinson's disease (PD, n = 361), as well as controls (n = 257). Although we have confirmed the previous results, in a larger sample, that the IL-1beta genotype has affected the age at onset of PD patients, no contribution of the GST-1 gene polymorphism was observed in the allele frequency or the onset age of the disease in Japanese persons.
Abstract: We studied promoter region polymorphisms in the tumor necrosis factor (TNF), interleukin (IL)-6, IL-10, and transforming growth factor (TGF)-beta1 genes in Japanese patients with multiple system atrophy (MSA) (n=122) and normal controls (n=277). The frequency of the TNF-1031C, a high producer allele of TNF, was increased significantly in MSA patients compared with controls (chi2=12.36, P=0.0021, Pc=0.0084). In contrast, there was no difference in the genotype or allele frequency in the other cytokine gene polymorphisms. We also failed to detect any difference in the disease onset between each genotype of the polymorphisms examined. Our findings suggest that TNF might have a toxic effect in MSA.
Abstract: Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disease characterized by various symptoms including cerebellar ataxia. Recently, several missense mutations in the protein kinase Cgamma (gammaPKC) gene have been found in different SCA14 families. To elucidate how the mutant gammaPKC causes SCA14, we examined the molecular properties of seven mutant (H101Y, G118D, S119P, S119F, Q127R, G128D, and F643L) gammaPKCs fused with green fluorescent protein (gammaPKC-GFP). Wild-type gammaPKC-GFP was expressed ubiquitously in the cytoplasm of CHO cells, whereas mutant gammaPKC-GFP tended to aggregate in the cytoplasm. The insolubility of mutant gammaPKC-GFP to Triton X-100 was increased and correlated with the extent of aggregation. gammaPKC-GFP in the Triton-insoluble fraction was rarely phosphorylated at Thr(514), whereas gammaPKC-GFP in the Triton-soluble fraction was phosphorylated. Furthermore, the stimulation of the P2Y receptor triggered the rapid aggregation of mutant gammaPKC-GFP within 10 min after transient translocation to the plasma membrane. Overexpression of the mutant gammaPKC-GFP caused cell death that was more prominent than wild type. The cytotoxicity was exacerbated in parallel with the expression level of the mutant. These results indicate that SCA14 mutations make gammaPKC form cytoplasmic aggregates, suggesting the involvement of this property in the etiology of SCA14.
Abstract: Various factors have been suggested to participate in Alzheimer's disease (AD) pathology, and some inflammatory cytokines may play an important role in the development of AD. Interferon-gamma (IFNG), an important pro-inflammatory cytokine, is encoded by a single gene mapped to chromosome 12, one of the candidate locus of AD. The first intron in the IFNG gene represents a CA repeat polymorphism that is possible to affect the IFNG secretion dose. We speculate that the polymorphism may have some roles on the inflammatory process and the pathologic change in AD, so we analyzed the IFNG gene polymorphism in 199 Japanese AD patients and 225 Japanese controls. There were no significant differences in allele frequency between the AD and control groups. We conclude that IFNG gene polymorphism is not associated with development of AD.
Abstract: BACKGROUND: Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant cerebellar ataxia caused by CAG trinucleotide expansion. The characteristics of regional cerebral blood flow (rCBF) in SCA6 patients have not been established, whereas it has been reported that decreased rCBF in the cerebrum seems to be a remote effect of cerebellar impairment in other cerebellar disorders. OBJECTIVE: To clarify the characteristics of rCBF, including cerebro-cerebellar relationship, and its correlation with clinical manifestations in patients with genetically confirmed SCA6 using quantitative assessment of rCBF by brain single-photon emission computed tomography (SPECT). DESIGN: Technetium Tc 99m ethyl cysteinate dimer SPECT study using a Patlak plot.Patients Hiroshima University Hospital, Hiroshima, Japan. Ten patients with SCA6 and 9 healthy controls.Main Outcome Measure The rCBF of the cerebellar vermis, cerebellar hemisphere, and frontal lobes. RESULTS: In SCA6 patients, rCBF was decreased only in the cerebellar vermis and hemisphere compared with healthy controls, and this was inversely correlated with duration of illness. The rCBF in the frontal lobes was slightly correlated with duration of illness without statistical significance. The rCBF in the vermis was inversely correlated with severity of dysarthria, but there was no significant correlation with CAG repeated expansions. CONCLUSIONS: Decrease in rCBF was found only in the cerebellum and was associated with duration of illness, dysarthria and ataxia, and cerebellar atrophy. No remote effect of cerebellar hypoperfusion was found in the SCA6 patients.
Abstract: BACKGROUND: Spinocerebellar ataxia type 17 (SCA17) is an autosomal dominant cerebellar ataxia caused by expansion of CAG/CAA trinucleotide repeats in the TATA-binding protein (TBP) gene. Because the number of triplets in patients with SCA17 in previous studies ranged from 43 to 63, the normal number of trinucleotide units has been considered to be 42 or less. However, some healthy subjects in SCA17 pedigrees carry alleles with the same number of expanded repeats as patients with SCA17. OBJECTIVE: To investigate the minimum number of CAG/CAA repeats in the TBP gene that causes SCA17. DESIGN: We amplified the region of the TBP gene containing the CAG/CAA repeat by means of polymerase chain reaction and performed fragment and sequence analyses. PATIENTS: The subjects included 734 patients with SCA (480 patients with sporadic SCA and 254 patients with familial SCA) without CAG repeat expansions at the SCA1, SCA2, Machado-Joseph disease, SCA6, SCA7, or dentatorubral-pallidolluysian atrophy loci, with 162 healthy subjects, 216 patients with Parkinson disease, and 195 with Alzheimer disease as control subjects. RESULTS: Eight patients with SCA possessed an allele with more than 43 CAG/CAA repeats. Among the non-SCA groups, alleles with 43 to 45 repeats were seen in 3 healthy subjects and 2 with Parkinson disease. In 1 SCA pedigree, a patient with possible SCA17 and her healthy sister had alleles with 45 repeats. A 34-year-old man carrying alleles with 47 and 44 repeats (47/44) had developed progressive cerebellar ataxia and myoclonus at 25 years of age, and he exhibited dementia and pyramidal signs. He was the only affected person in his pedigree, although his father and mother carried alleles with mildly expanded repeats (44/36 and 47/36, respectively). In another pedigree, 1 patient carried a 43-repeat allele, whereas another patient had 2 normal alleles, indicating that the 43-repeat allele may not be pathologic in this family. CONCLUSIONS: We estimate that 44 CAG/CAA repeats is the minimum number required to cause SCA17. However, the existence of unaffected subjects with mildly expanded triplets suggests that the TBP gene mutation may not penetrate fully. Homozygosity of alleles with mildly expanded triplet repeats in the TBP gene might contribute to the pathologic phenotype.
Abstract: We studied promoter region polymorphisms in the interleukin (IL)-1alpha, IL-1beta, IL-6, IL-10, tumor necrosis factor, and transforming growth factor (TGF)-beta1 genes in Japanese patients with Alzheimer's disease (AD) (n = 172) and normal controls (n = 163). We also examined an association of a polymorphism located in the glutathione S-transferase omega 1 (GSTO-1) gene region with AD patients. None of these genotypes or allele frequencies showed a significant difference between AD patients and controls. We also failed to detect any difference in the disease onset between each genotype of the seven polymorphisms. Although AD patients carrying high producer alleles of TGF-beta1 and IL-1beta or TGF-beta1 and IL-6 showed a tendency for an early onset of the disease, neither of these combined effects reached a significant level after multiple comparisons. Our findings suggest that genetic polymorphisms in the cytokines and GSTO do not play a major role in Japanese AD patients.
Abstract: The highest prevalence rate of spinocerebellar ataxia type 6 (SCA6) in the worldwide population is in the Chugoku and Kansai areas of Western Japan, but the reason of this geographic characteristics is unclear. We investigated the predisposing haplotypes and their geographic distribution. Genotyping of five microsatellite markers and three single nucleotide polymorphisms linked to the CACNA1A gene in 150 Japanese SCA6 patients from unrelated 118 families revealed three major haplotypes, carrying a pool of one common haplotype core. A founder chromosome was thought to have historically diverged into at least three types. One of the major haplotypes newly identified showed a strong geographical cluster around the Seto Inland Sea in the Chugoku and Kansai areas of Western Japan, whereas the others were widely distributed throughout Japan. The distribution of predisposing haplotypes contributes to the geographical differences in prevalence of SCA6.
Abstract: We analyzed the SCA8 CTA/CTG repeat in a large group of Japanese subjects. The frequency of large alleles (85-399 CTA/CTG repeats) was 1.9% in spinocerebellar ataxia (SCA), 0.4% in Parkinson disease, 0.3% in Alzheimer disease, and 0% in a healthy control group; the frequency was significantly higher in the group with SCA than in the control group. Homozygotes for large alleles were observed only in the group with SCA. In five patients with SCA from two families, a large SCA8 CTA/CTG repeat and a large SCA6 CAG repeat coexisted. Age at onset was correlated with SCA8 repeats rather than SCA6 repeats in these five patients. In one of these families, at least one patient showed only a large SCA8 CTA/CTG repeat allele, with no large SCA6 CAG repeat allele. We speculate that the presence of a large SCA8 CTA/CTG repeat allele influences the function of channels such as alpha(1A)-voltage-dependent calcium channel through changing or aberrant splicing, resulting in the development of cerebellar ataxia, especially in homozygous patients.
Abstract: Human T-cell leukemia virus type I (HTLV-I) provirus load differs more than 100-fold among carriers and a high provirus load in the peripheral blood mononuclear cells (PBMCs) is regarded as a risk factor for both preleukemic states and inflammatory diseases including HTLV-I-associated myelopathy (HAM). We examined polymorphisms in the genes for tumor necrosis factor (TNF), TNF receptor type 1 and 2, lymphotoxin (LT)-alpha, interleukin (IL)-1beta, IL-6, IL-10, monocyte chemoattractant protein (MCP)-1, and mannose binding protein (ManBP) in 143 HTLV-I carriers whether these polymorphisms affect the provirus load in the PBMCs of carriers. No significant association was observed between these polymorphisms and the provirus load. Homozygotes for a ManBP-variant allele, however, showed a tendency for the decreased number of provirus load. When combined, the data on the alleles of LT-alpha and MCP-1, HTLV-I carriers having high producer alleles of both genes showed a trend for increased provirus load. These data suggest that inflammation or an active immune response may induce an increased amount of HTLV-I-infected T cells, leading to a high provirus load.
Abstract: We studied polymorphisms in the genes for monocyte chemoattractant protein 1 (MCP-1) and CC chemokine receptor (CCR)-2 in 171 Parkinson's disease (PD) patients and 340 controls. Although no associations were found in alleles or genotypes, MCP-1 -2518A/G genotype affected the age-at-onset of PD patients. This effect was also detected in a second PD group, suggesting a possible involvement of MCP-1 in PD.
Abstract: The authors describe a 16-year-old boy with severe muscular atrophy and signs of peripheral neuropathy compatible with Charcot-Marie-Tooth disease. Abnormalities in the cerebellum and central somatosensory pathway were also noted. Gene analysis revealed a novel gross insertion mutation in exon 2 of the connexin32 gene along with a 21-base pair duplication resulting in a seven-amino acid insertion in the first extracellular loop of the protein.
Abstract: Expansions of trinucleotide repeats have been discovered in spinocerebellar ataxia (SCA) types 1, 2, 6, 7, 12, and 17, Machado-Joseph disease (MJD/SCA3), and dentatorubropallidoluysian atrophy (DRPLA). However, the frequency of familial SCA in Japan remains unclear. The number of trinucleotide repeats was determined for 1,286 patients. Three hundred and thirty families (523 cases) were autosomal dominant group (A), and 165 families were positive for family history but not autosomal dominant group (B), while the remaining 598 cases were the sporadic group (C). The frequency of SCA subtypes in autosomal dominant group was: 1) 5.5% for SCA1; 2) 2.4% for SCA2; 3) 27.6% for MJD/SCA3; 4) 25.5% for SCA6; 5) 0.3% for SCA17; and 6) 7.3% for DRPLA. Abnormal expansion of SCA12 was not detected. Another 31.5% of the patients in the autosomal dominant group had unknown genetic abnormalities. Within group B, SCA6 was the most prominent and within the sporadic group MJD/SCA3 and SCA6 were the most common subtypes observed. The disease-free survival curve of SCA6 was different from that of other SCAs and the mean age at onset for SCA6 was found to be later than that of the other types. Regional differences were observed in the relative rate of SCA subtypes. MJD/SCA3 appears more common in the Kanto and Kyushu districts of Japan, whereas SCA6 is most common in the Chugoku district. In order to establish an effective social welfare system for SCA patients, clinical course and regional differences in the prevalence of SCA subtypes must be taken into consideration.
Abstract: In the pathological process of Alzheimer's disease (AD), deposition of amyloid beta-peptide (A beta) in the brain parenchyma plays an important role. Neprilysin (NEP), a neutral endopeptidase, degrades A beta, and it is postulated that decreased NEP activity may contribute to the development of AD by promoting the accumulation of A beta. The human NEP gene possesses four dinucleotide repeat polymorphisms, and it is possible that these polymorphisms regulate the NEP expression levels and influence the pathological cascade of AD. Therefore, we investigated the association of these polymorphisms with AD. We performed genotyping of each polymorphism in 201 Japanese sporadic AD patients and 208 Japanese controls. There were no significant differences between the AD and control groups in allele frequencies of each polymorphism. We conclude that these polymorphisms in the NEP gene do not contribute to genetic risk factors for sporadic AD.
Abstract: It has been reported that nicotine shows some beneficial effects on Parkinson's disease. The purpose of the present study is to assess the therapeutic effects of nicotine chewing gum in patients with early-onset parkinsonism (EOP). The subjects were 8 patients with early-onset parkinsonism (male/female = 4/4, mean age; 51.3 years). Four out of 8 patients had a history of smoking (smokers). To estimate the effects of nicotine gum, the scores on the Unified Parkinson's Disease Rating Scale (UPDRS) and auditory event-related potentials (ERPs) were studied before and after taking nicotine gum in the EOP patients. In smokers, UPDRS scores improved by more than 10% and the P300 latency of auditory ERPs was shortened by more than 30 msec. In contrast, nicotine had no remarkable effects on UPDRS scores or auditory ERPs in non-smokers. We suggest that nicotine chewing gum may be a possible choice for the treatment of patients with EOP, especially when they are smokers.
Abstract: We studied cytokine gene polymorphisms in the promoter region, including interleukin (IL)-6, IL-1beta, and IL-10, in Japanese patients with human T-cell leukemia virus type I (HTLV-I) associated myelopathy (HAM) (n = 65), asymptomatic HTLV-I carriers (n = 143), and HTLV-I seronegative, normal controls (n = 160). There was a significant difference between HAM patients and HTLV-I carriers in the distribution of IL-6 promoter polymorphism at position -634 (chi(2) = 9.90, p = 0.0071). The IL-6 genotype was also significantly different between HAM patients and normal controls (chi(2) = 11.53, p = 0.0033), while a similar distribution was observed in IL-1beta and IL-10 polymorphisms among HAM patients, carriers, and normal controls. The results suggest that IL-6 gene region may contribute to susceptibility to HAM, and that aberrant cytokine productions could be involved in the development of HAM.
Abstract: We studied genetic polymorphisms in the promoter region at position -511 of the interleukin (IL) -1beta gene (IL-1B-511) and at position -889 of the IL-1alpha gene (IL-1A-889), in 111 Japanese patients with multiple system atrophy (MSA) and 160 controls. The distribution of IL-1B-511 was significantly different between MSA patients and controls, because of the under-representation of patients with homozygotes for allele 2 (IL-1B-511*2), a high producer of IL-1beta. The frequency of IL-1A-889*2, a high secretor of IL-1alpha, was also decreased in MSA patients. Our findings suggest that abnormal cytokine expression may be implicated in the pathogenesis of MSA.
Abstract: A 61-year-old woman had repeated episodes of muscle weakness of face, neck and limbs for 18 years. She was diagnosed as having myasthenia gravis (MG) by the positive anti-acetylcholine receptor antibody and findings of electromyogram. Simultaneously, she was noticed to have diabetes mellitus with high titers of anti-glutamic acid decarboxylase (GAD) antibody. Magnetic resonance imaging showed a large thymoma. In spite of the improvement of MG after thymectomy, the insulin secretion slowly exacerbated during next two years. The clinical course of her disease was characteristic as slowly progressive insulin dependent diabetes mellitus (SPIDDM). She continued to have positive autoantibody against beta-cell of pancreas. Recently, anti-GAD antibody is detected in patients with SPIDDM and stiffman syndrome (SS) in high rate, and it is closely associated with the cause of these syndromes. The patient did not reveal the symptoms of SS. From the clinical course, MG and SPIDDM in this patient may be caused by a common underlying autoimmune abnormality resulting from the long presence of the thymoma. MG and SPIDDM may be derived from organ-specific autoimmunopathy from the defect of self-tolerance.
Abstract: Nicotinic acetylcholine receptor (nAChR) in the central nervous system represents a new potential therapeutic target in neurodegenerative diseases, and this is driven by new findings in the molecular biology of nicotinic ion channel. Results of epidemiological studies have revealed that the incidence of Alzheimer's disease is lower among smokers compared with findings for nonsmokers, which seems to indicate that nicotine may influence cortical functions. We observed an increase in extracellular dopamine concentrations after administration of nicotine through a microdialysis tube. Nicotine might inhibit the uptake of dopamine through the nAChR, which could serve as a preventive factor against neurodegenerative diseases. We evaluated the ability of nicotine to protect neuronal cells from death by using the model system of serum- and nerve growth factor (NGF)-free cultures of PC12 cells. Serum and NGF deprivation induced rapid and massive death of these cells, which was inhibited by the addition of nicotine. These results suggest to us that nicotine may be involved in the protection of neuronal cells from death by means of nAChR. The effect of NGF and nicotine on the expression of nAChR subunits in PC12 cells was examined by using Northern blot analysis. Nerve growth factor increased the transcription of alpha5 and beta4 subunits, whereas nicotine increased mRNA level encoding alpha5 and beta2 subunits. These results suggest to us that NGF changes the expression of nAChR in a subtype-specific manner over the course of differentiation, and disproportionate subunit expressions might be related to the neuroprotective effect exerted by nicotine.
Abstract: Associations between polymorphisms of the cystatin C gene (CST3) at 5' flanking region and exon 1 in Caucasian patients with late onset AD and exon 1 in a US study of late onset AD have been reported. Clinically diagnosed Japanese patients with AD and Japanese normal control subjects were assessed for the presence of polymorphisms of CST3. The authors could not confirm the previously reported association between CST3 polymorphisms and AD in Japan. Age had no effect on the CST3 genotype.
Abstract: An inverse correlation is observed between the expanded CAG repeat number and age-at-onset of spinocerebellar ataxia 6 (SCA6). To detect another modifying genetic factor for SCA6, we studied polymorphisms in the genes for interleukin (IL)-1beta and tumor necrosis factor in 122 Japanese patients with SCA6. No contribution of these polymorphisms to the variance in disease onset was observed by regression analysis or by ANOVA. The IL-1beta promoter polymorphism, however, significantly affected the age-at-onset, when adjusted for the CAG repeat number as a covariate (P=0.0004, by ANCOVA), suggesting that IL-1beta may be a genetic factor other than the SCA6 gene that modifies the age-at-onset of the disease.
Abstract: Dinucleotide repeat polymorphism has been observed in the promoter of the alpha-synuclein (alpha-SYN)/NAC precursor protein (NACP) gene. Alpha-SYN/NACP allele 3 (described by Xia et al. (Ann. Neurol., 40 (1996) 207), equivalent to allele 1 described by Krüger et al. (Ann. Neurol. 45 (1999) 611) is reported to be significantly more frequent among patients with sporadic Parkinson's disease (sPD) than controls. In this study, we genotyped the same alpha-SYN/NACP polymorphism in Japanese sPD patients and healthy controls, but found that any aliele showed no significant difference between the two groups.
Abstract: Cerebral white matter lesions, such as leukoaraiosis, may be a result of damage from cerebral ischaemia, and may also be associated with the degenerative process in Alzheimer's disease. The apolipoprotein epsilon4 (apoepsilon4) genotype is a genetic risk factor for both Alzheimer's disease and ischaemic brain damage through acceleration of atherosclerosis. The aim was to determine whether apoepsilon4 may be related to the formation of cerebral white matter lesions in Alzheimer's disease. The association of apoE genotype, sex, age, and the presence of several vascular risk factors, with the presence of white matter lesions in 55 patients clinically diagnosed with Alzheimer's disease was investigated. The cerebral white matter lesions were identified by T2 weighted MRI and classified on a 4 grade scale from no lesion to diffuse lesion. The odds ratio (OR) of the factors mentioned above to the presence of white matter lesions was determined and tested by Fisher's exact test. The association of the lesion grades with these factors was analysed by non-parametric tests. The apoE 4 genotype was strongly associated with Alzheimer's disease (p=0.0001), but not associated with the presence or the degree of cerebral white matter lesions in Alzheimer's disease (OR=1.09, p>0.99). Aging (>70 years old) was a significant risk factor for white matter lesions (OR=7.2, p=0.0006) and age was significantly correlated with the lesion (p=0.0075). The OR of female sex to the lesion grades was 2.89 (p=0.084) and the lesion grade of female sex was significantly higher than that of the male sex (p=0.047). Other vascular risk factors were not significantly associated with the presence of white matter lesions. These findings suggest that there is a sex difference in white matter pathology in Alzheimer's disease.
Abstract: We studied tumor necrosis factor (TNF), lymphotoxin-alpha (LT-alpha), and TNF receptors type 1 (TNFR-1) and type 2 (TNFR-2) gene polymorphisms as well as HLA class II DRB1 alleles in Japanese patients with human T-cell lymphotropic virus type I (HTLV-I) associated myelopathy (HAM) (n = 51), patients with adult T-cell leukemia/lymphoma (ATL) (n = 48), asymptomatic HTLV-I carriers (n = 50), and HTLV-I seronegative, normal controls (n = 112). There were significant differences between HAM patients and normal controls in the distributions of TNF promoter region polymophism at position --857, the LT-alpha gene NcoI polymorphism, and the T-G substitution in exon 6 of the TNFR-2 gene. The distribution of the NcoI polymorphism of the LT-alpha gene was also significantly different between HAM patients and asymptomatic HTLV-I carriers. In contrast, we failed to detect any difference in the frequency of DRB1, TNF promoter at position --1031, --863, or the TNFR-1 promoter --383 polymorphism. The results suggest that the TNF/LT-alpha gene region within the HLA class III of chromosome 6 and the TNFR-2 gene region located on chromosome 1p36 might contribute to susceptibility to HAM, and that aberrant expression or function of these cytokines and the receptor could be involved in the development of HAM.
Abstract: BACKGROUND: Long-term cognitive decline in postmenopausal women is associated with aging and Alzheimer disease (AD). Estrogen replacement therapy has been reported to reduce the risk of developing AD. The distribution of estrogen receptors (ERs) in neurons overlaps that of the brain neurons known to develop AD. Estrogen increases the secretion and metabolism of amyloid precursor protein, may help synapse formation, and is reported to protect neurons from toxins. Restriction fragment length polymorphisms (RFLPs) of the ERalpha gene at intron 1 and exon 2 were associated with a low bone mineral density in postmenopausal women and also with AD in a Japanese population. OBJECTIVE: To determine whether ERalpha gene polymorphisms are associated with transcriptional activity and AD. METHODS: A luciferase reporter assay analyzed enhancer activity of the ERalpha gene at intron 1 and exon 2. This activity was evaluated according to the RFLPs. The RFLPs of the ERalpha gene were determined in Japanese patients clinically diagnosed as having AD, white patients diagnosed as having AD at autopsy, and corresponding healthy control subjects. The RFLPs were also evaluated for the contribution of the ERalpha gene RFLPs to AD. RESULTS: We found weak (about 2-fold) enhancer activity of the ERalpha gene, which differed among RFLPs. Although there were racial differences in these polymorphisms, we could not confirm the previously reported association between ERalpha gene polymorphisms and AD. CONCLUSION: Regulatory element of the ERalpha gene was found in intron 1, but we found no association between ERalpha gene polymorphisms and AD.
Abstract: In spinocerebellar ataxia type 6 (SCA6), the cerebellum is predominantly affected, but several electrophysiological studies have revealed subclinical disorders other than cerebellar lesions. We conducted statistical analyses by comparing SCA6 patients and age-matched normal controls to asses whether electrophysiological abnormalities are directly associated with SCA6 because late onset of SCA6 may involve senile changes. We performed brain stem auditory evoked potentials (BAEP), visual evoked potentials, somatosensory evoked potentials and nerve conduction studies in 10 SCA6 patients. The BAEP latencies of wave I was prolonged and compound muscle action potentials of peroneal nerve and sensory nerve action potentials of sural nerve reduced in SCA6 patients. Our results suggest an existence of peripheral impairment in the auditory pathway and axonal neuropathy in SCA6.
Abstract: We identified two polymorphisms out of all coding regions of the dopamine transporter gene. One existed in exon 9 (1215A/G) and another in exon 15 (1898T/C). The 1215G was significantly less frequent among patients with Parkinson's disease than the controls. Although the polymorphism caused no amino acid substitution, we concluded that it was associated with decreasing the susceptibility to Parkinson's disease through mechanisms other than the protein function of dopamine transporter.
Abstract: We isolated and characterized the human NeuroD-related factor (NDRF)/NeuroD2/KW8 gene. The NDRF gene consisted of two exons and one intron. NDRF had one transcriptional starting point, and in its 5'-flanking region, no TATA box was detected, but 16 E boxes (CANNTG) were present. RNA blotting analysis revealed that HIT-T15 and D283 cells expressed a 3.3 kb band of the NDRF transcript. Promoter analysis by luciferase assay demonstrated that luciferase activity changed between -120 and -195, and between -451 and -564, both regions wherein a single E box existed. Radiation hybrid mapping showed that NDRF linked the marker SHGC-36242 with a LOD score of 8.53 and was located on 17q12-22.
Abstract: We reported a 73-year-old woman of spinocerebellar ataxia 6 (SCA 6). There was no family history of neurological diseases. She demonstrated cerebellar ataxia and scanning speech at the age of 48. These symptoms gradually developed. Brain MRI showed severe cerebellar atrophy and no abnormality in the brain stem. Her neurological symptoms and MRI findings were compatible with cerebellocortical atrophy (CCA). Analysis of the CACNL1A4 gene on chromosome 19p 13 demonstrated she had an expanded allele with 27 CAG repeats. Therefore, she was diagnosed with SCA 6. In spite of her large CAG expansion, there was no family history of SCA 6 in this case. SCA 6 needs to be ruled out in cases of clinical CCA.
Abstract: Recent reports have revealed that Nurr1 (also known as NOT/TINUR/RNR-1/HZF-3), a member of the steroid/thyroid hormone nuclear receptor superfamily, is predominantly expressed in the midbrain; substantia nigra (SN) and ventral tegmental area (VTA). Nurr1 null mice are born lethal, lacking the midbrain dopamine (DA) neurons, suggesting that Nurr1 is essential for the development and differentiation of midbrain DA neurons. Human Nurr1 gene has been mapped on chromosome 2q22-23, which is reported to associate weakly with schizophrenia. We cloned and sequenced the human Nurr1 gene, which is approximately 8.3kb long, consisting of eight exons and seven introns. Comparisons of the human Nurr1 with the mouse Nurr1, mouse Nur77 and human NOR-1 revealed that their genomic structures were highly conserved. The 5'-flanking region of the human Nurr1 included three transcriptional regulatory elements, cAMP-response element (CRE), CArG-like element and Sp-1 site, which were surrounded by CpG island, and showed a strong homology with the mouse Nurr1. We performed a primer extension analysis using mRNA from HeLa S3 cells stimulated with phorbol 12-myristate 13-acetate (PMA), Ca2+ ionophore A23187 and cycloheximide (CHX) in order to induce the Nurr1 mRNA expression, and determined one transcription initiation site within CRE. The transient transfection assay indicates that the regulatory elements in the 5'-flanking region are robust for mitogen-induced expression of the human Nurr1. Further analysis of the polymorphism of the human Nurr1 gene may reveal the association with diseases characterized by changes of the DA system, such as Parkinson's disease and schizophrenia.
Abstract: A recent observation has shown that a common polymorphism (-491 A) in the promoter of apolipoprotein E (APOE) was associated with an increased risk for Alzheimer's disease (AD) in European decent. Moreover, the promoter with -491 A showed higher transcriptional activity than that with -491 T. To investigate the further contribution of the polymorphism to the etiology of sporadic AD, we evaluated associations between Japanese AD and -491 A/T polymorphism of APOE. There was no significant difference between these cases and controls. The percentage of the homozygote of -491 A allele (AA) among the Japanese control population was significantly higher than that among the Spanish control population. The APOE promoter genotype frequencies may be influenced by the ethnic background. Our study failed to confirm any relationship between -491 A/T polymorphism and AD. Thus, we conclude that the APOE promoter polymorphism does not represent an additional risk factor for AD in Japanese populations.
Abstract: Spinocerebellar ataxia 6 (SCA6) is caused by expansion of a polyglutamine stretch, encoded by a CAG trinucleotide repeat, in the human P/Q-type Ca(2+) channel alpha(1A) subunit. Although SCA6 shares common features with other neurodegenerative glutamine repeat disorders, the polyglutamine repeats in SCA6 are exceptionally small, ranging from 21 to 33. Because this size is too small to form insoluble aggregates that have been blamed for the cause of neurodegeneration, SCA6 is the disorder suitable for exploring the pathogenic mechanisms other than aggregate formation, whose universal role has been questioned. To characterize the pathogenic process of SCA6, we studied the effects of polyglutamine expansion on channel properties by analyzing currents flowing through the P/Q-type Ca(2+) channels with an expanded stretch of 24, 30, or 40 polyglutamines, recombinantly expressed in baby hamster kidney cells. Whereas the Ca(2+) channels with </=24 polyglutamines showed normal properties, the Ca(2+) channels with 30 or 40 polyglutamines exhibited an 8 mV hyperpolarizing shift in the voltage dependence of inactivation, which considerably reduces the available channel population at a resting membrane potential. The results suggest that polyglutamine expansion in SCA6 leads to neuronal death and cerebellar atrophy through reduction in Ca(2+) influx into Purkinje cells and other neurons. Besides the widely accepted notion that polyglutamine stretches exert toxic effects by forming aggregates, expanded polyglutamines directly alter functions of the affected gene product.
Abstract: Variation in the number of CAG repeats in the Machado-Joseph disease gene (MJD1) was examined by polymerase chain reaction and denaturing polyacrylamide gel electrophoresis analysis of 2134 normal and 135 affected chromosomes of Japanese individuals. The number of repeats ranged from 14 to 47 in normal alleles and from 61 to 84 in disease-associated alleles. The most frequent and lowest number of repeats was 14. The size distribution of normal MJD1 alleles did not fit a normal distribution curve, but was tetramodal. Repeats from 14 to 17, 18 to 23, 24 to 25, and 26 to 47 units were designated groups A through D, respectively. When examined Hardy-Weinberg equilibrium by chi-square analysis of goodness of fit: no evidence of significant deviation from the Hardy-Weinberg equilibrium was observed [x2=4.248<16.919 (P=0.05), df=9]. The observed distribution peak of normal MJD1 alleles corresponding to peptides containing 10, 15, 20, and 24 glutamine suggests that stretches of 5 and 10 glutamine might constitute a functional domain of human MJD1.
Abstract: The neuroprotective effect of nicotine via nicotinic acetylcholine receptor (nAChR) has been reported in differentiated PC12 cells. We examined the effects of nerve growth factor (NGF) and nicotine on the expressions of the nAChR subunits alpha3, alpha5, alpha7, beta2, beta3 and beta4, in PC12 cells using Northern blot analysis. NGF increased the transcriptions of alpha5 (1,4- to 2,3-fold), alpha7 (1.7- to 2.5-fold) and beta4 (1.9- to 3.0-fold) subunits, but changes in alpha3 and beta2 subunit levels were smaller than alpha5, alpha7, or beta4. Nicotine also increased the levels of mRNA encoding alpha5 and beta2 subunits. The pattern of subunit mRNA changes was different between NGF and nicotine treatment. No signal for beta3 subunit was detected. The results suggest that NGF changes the expression of nAChR in a subtype-specific manner over the course of the differentiation, and the disproportionate subunit expressions might be related to the neuroprotective effect exerted by nicotine.
Abstract: The effect of CAT trinucleotide interruptions in the CAG trinucleotide repeats of the SCA1 gene on the age at onset of spinocerebellar ataxia type 1 (SCA1) was investigated. The number of CAG repeats in SCA1 was determined by polymerase chain reaction (PCR) analysis, and the presence of CAT interruptions was assessed on the basis of the sensitivity of the PCR products to the restriction endonuclease SfaNI, which recognises CAT trinucleotides. Only one in 17 expanded SCA1 alleles from 17 SCA1 patients was interrupted by CAT. The SfaNI sensitive SCA1 allele from this single patient contained 58 CAG repeats, which would predict an age at onset of SCA1 of 22.0 years, in contrast to the actual 50 years. In addition, the brain stem atrophy of this patient was mild compared with that of a patient with 52 uninterrupted CAG repeats. A sequence analysis showed that the repeat portion of the patient contained (CAG)45CATCAG CAT(CAG)10. From these results, we suggest that the age at onset of SCA1 is not determined by the total number of CAG repeats (58) but by the number of uninterrupted CAG repeats.
Abstract: The major symptom of spinocerebellar ataxia type 6 (SCA6) is progressive cerebellar ataxia. MRI revealed isolated cerebellar atrophy without brainstem and cerebral involvement. Up to the present electrophysiological abnormalities in patients with SCA6 have not been intensively investigated. We performed electrophysiological examination, such as multi-modality evoked potentials, in 10 patients with SCA6. We analyzed the electrophysiological data including the results previously reported. When compared with SCA1, 2 and MJD, specific findings in electrophysiological studies are obscure in SCA6. Existence of subclinical lesions in peripheral nerves, pyramidal tract, auditory pathway, visual pathway, and sensory pathway was suggested in some cases with SCA6. It is important to consider the effect of age, because age at onset is relatively late in SCA6.
Abstract: The purpose of the present study was to assess the relationship between clinical characteristics of spinocerebellar ataxia type 6 (SCA6) and CAG repeat length. MATERIALS AND METHODS: We examined clinical symptoms of 54 patients with SCA6. CAG repeat length was compared among subgroups divided by clinical manifestations. RESULTS: The major symptom was progressive cerebellar ataxia. Truncal or limb ataxia, dysarthria, and nystagmus were observed in more than 80% of the patients. In analysis of CAG repeat length in patients with different types of nystagmus, CAG repeat length was the longest when both upbeat and downbeat nystagmus existed (P < 0.01). In addition, CAG repeat length was longer when the initial symptom was ataxic gait and was shorter when the initial symptom was dysarthria or ocular symptom (P < 0.05). CONCLUSION: Clinical features of SCA6 might be influenced by the length of abnormal CAG repeat.
Abstract: In this study, we isolated and characterized the human NeuroD (BETA2/BHF1) gene. This gene was found to consist of two exons and one intron. The promoter regions were well-conserved compared with the mouse NeuroD gene. Two transcription start points (TSPs) were determined by the oligo-capping method. One TATA box was located at -31 bp from the lower TSP. The results of a transient transfection assay using the human neuroblastoma cell line IMR-32 and hamster insulin tumor cell line HIT-T15 suggested that there are at least three positive regulatory regions in the promoter. In these regions, four E boxes (CANNTG), named the E1 to E4 boxes, and two GC boxes were present. Cotransfection of the NeuroD expression vector into IMR-32 cells enhanced the NeuroD promoter activity by about 4-fold. A deletion and mutation analysis revealed that the E1 and E4 boxes, especially the E1 box, are associated with autoactivation and that E2 and E3 boxes are not associated with autoactivation. As mutation analysis of E3 box showed a decrease in the enhancer activity to the basal level, it showed that the E3 box is important to activate the NeuroD transcription. These results raised the possibility that the NeuroD gene expression is positively regulated through the E box sequence, not only by NeuroD itself but also by another E box binding protein.
Abstract: There are two types of neurotransmitter transporters whose structure is known. One is a glutamate transporter family. The glutamate transporter takes up glutamate to terminate neurotransmission and to prevent neuronal cell death. The transporter may play important roles of cause and development in the neurological diseases. Another type is a catecholamine transporter family with 12 transmembrane domains. Dopamine transporter of the family takes up 1-methyl-4-phenylpyridinium (MPP+) and causes dopaminergic cell death.
Abstract: OBJECTIVE: To clarify the characteristic magnetic resonance imaging (MRI) findings in patients with Machado-Joseph disease (MJD) diagnosed by genetic analysis. PATIENTS AND METHODS: Using MRI, we examined 31 patients genetically diagnosed as having MJD, 20 patients with sporadic olivopontocerebellar atrophy, and 26 control subjects. RESULTS: The MRIs of patients with MJD disclosed remarkably reduced width of the superior cerebellar peduncles, atrophy in the frontal and temporal lobes, diminished transverse diameter of the globus pallidus, and decreased anteroposterior and transverse diameters of the pons, which correlated with the width of the middle cerebellar peduncle. The width of the superior cerebellar peduncles also correlated with the diameter of the dentate or red nucleus in patients with MJD, but not in controls or in patients with sporadic olivopontocerebellar atrophy. On T2- and/or proton-weighted axial MR imaging, a high signal intensity in the transverse pontine fibers was observed in 14 (45.2%) of 31 patients with MJD and in all patients with sporadic olivopontocerebellar atrophy, but not in any controls. CONCLUSION: Affected afferent and efferent cerebellar tracts and atrophy of the frontal and temporal lobes and globus pallidus are characteristics of MRI of patients with MJD.
Abstract: OBJECTIVE: To clarify the characteristic magnetic resonance imaging (MRI) findings in patients with spinocerebellar ataxia 6 (SCA6) diagnosed by genetic analysis. PATIENTS AND METHODS: Using MRI, we examined 10 patients genetically diagnosed as having SCA6 and 40 control subjects. RESULTS: The mean (+/-SD) CAG repeat length in 10 patients with SCA6 was 22.9 +/- 1.3. There was a significant inverse correlation between the CAG repeat size and age at onset in the SCA6 group (r = -0.86, P = .003). In patients with SCA6, the areas of the cerebellar vermis and hemispheres in sagittal MRI were significantly smaller than those in the control subjects. In transaxial MRI, the anteroposterior diameter of the pons and the diameter of the middle cerebellar peduncle were mildly decreased and the red nucleus was slightly atrophied in patients with SCA6. There was no significant difference in the diameter of the midbrain, medulla oblongata, fourth ventricle, superior cerebellar peduncles, dentate nucleus, or globus pallidus between the SCA6 and control groups. A high-signal intensity in the transverse pontine fibers was not observed in any of the patients with SCA6 on T2-weighted and/or proton-weighted axial MRI. CONCLUSIONS: The cerebellum and its afferent and efferent systems were affected in patients with SCA6. These results seem to distinguish the MRI findings of SCA6 from those of other forms of spinocerebellar ataxia.
Abstract: Effect of amino acid ergot alkaloids on glutamate transport via the human glutamate transporter (hGluT-1) was investigated using hGluT-HeLaS3 cells, which stably expressed high levels of hGluT-1. Ergotamine enhanced the glutamate uptake of hGluT-HeLaS3 cells in a concentration-dependent manner, increasing the initial velocity of glutamate uptake by 1.45 times at 10 microM. Other amino acid alkaloids, bromocriptine and dihydroergotamine, also augmented glutamate uptake, whereas amine alkaloids, ergonovine or lisuride did not influence glutamate uptake. The accelerating effect required a preincubation longer than 5 min. Kinetic studies on hGluT-1 revealed that ergot alkaloids decreased a Michaelis constant (Km) for glutamate with unchanged maximum velocity. The effect of bromocriptine was not mediated by dopamine D1 or D2 receptors, and was independent of its antioxidant action. Amino acid ergot alkaloids may serve as a prototype for agents that regulate glutamate transporters. These results may be useful in exploring new agents for neurological diseases associated with glutamatergic neurotoxicity.
Abstract: We studied genetic polymorphisms in the tumor necrosis factor (TNF) region as well as HLA-DRB1 of 42 patients with Western-type multiple sclerosis (MS) and 38 with Asian-type MS in Japan. The sex ratio (Female:Male) was significantly higher in Asian than in Western type MS (3.8 vs. 1.3, P = 0.038). The frequency of HLA-DRB1 * 1501 allele in the Western-type MS group increased significantly compared with the control group, while Asian-type MS and control groups showed similar distribution in the frequencies of HLA-DRB1 alleles. No significant differences existed in the TNF region, however, including TNF-a microsatellite alleles. The results suggest that MS in Asians may present two different clinical and immunogenetic manifestations.
Abstract: Apolipoprotein E (apo E) epsilon4 is a risk factor for sporadic and late-onset familial Alzheimer's disease, but it is not well known whether the apo E is associated with spinocerebellar degeneration. We studied the frequency of apo E allele in 59 olivopontocerebellar atrophy (OPCA) patients, including 13 pathologically confirmed cases. The distribution of the apo E allele frequency did not differ between OPCA patients and controls. Apo E allele does not influence the development of OPCA.
Abstract: We report a family with autosomal recessive spastic paraplegia. Patient 1 was a 37-year-old woman and patient 2 was her 35-year-old sister. They showed spastic paraplegia with mild truncal ataxia and dysarthria but no dementia, epilepsy, myoclonus, or other involuntary movements. They were the products of a consanguineous marriage but the parents were neurologically normal. We analyzed the CAG repeats of the dentatorubral-pallidoluysian atrophy (DRPLA) gene in the family members. The patients were homozygous for an allele carrying an intermediate size of CAG repeats (41 or 40 repeats) in the DRPLA gene; the parents were heterozygous for an intermediate allele and a normal allele in this gene. Homozygosity for an intermediate allele in the DRPLA gene appears to have resulted in spastic paraplegia different from any DRPLA phenotype.
Abstract: The human dopamine transporter (hDAT) is a member of the subfamily of monoamine transporters which show a common topological structure and possess significant amino acid sequence homology. We isolated and characterized the hDAT gene including about 1 kb of 5'-flanking region. The hDAT gene spans over 64 kb, consisting of 15 exons separated by 14 introns. The intron-exon structure of the hDAT gene is most similar to that of the human noradrenaline transporter (hNAT) gene. Promoter sequence analysis demonstrated a 'TATA'-less, 'CAT'-less and G+C-rich structure. Two E box and several Sp-1-binding sites exist in the promoter region. These structural features are similar to that of the human D1A dopamine receptor gene and the human monoamine oxidase A gene. The transcription start site was determined by both 5'-RACE and RNase protection assay. We determined the 5' end of the mRNA by identifying the 5'-terminal cap-G residue in 5'-RACE and RNase protection assay.
Abstract: To evaluate the clinical characteristics of Machado-Joseph disease (MJD) with reference to CAG repeat length and disease duration, we analyzed neurologic findings in 108 patients from 84 families. The majority of MJD patients presented with an ataxic gait as the initial symptom. Dysarthria and nystagmus were observed from an early stage. Bulging eyes, muscle atrophy and bradykinesia developed later. Patients with a shorter CAG repeat length or later onset had more frequent involvement of proprioceptive sensory deficit. Incidence of abnormal reflexes, tones, and proprioceptive sensation was not associated with disease duration, but with CAG repeat length. Based on these results, we propose a new clinical classification: type A (juvenile type), with hyperreflexia and dystonia, but without a proprioceptive sensory deficit; type C (adult type), with hyporeflexia and a proprioceptive sensory deficit, but without dystonia; and type B (intermediate type), the remaining patients with a mixed presentation.
Abstract: We investigated a patient with mitochondrial myopathy accompanied by cardiomyopathy. Molecular analysis disclosed a C-to-G substitution at nucleotide position 3254 of the mitochondrial tRNA(Leu)(UUR). Pedigree analysis revealed that this mutation was inherited maternally. Mutation C3254G may also be a candidate for genetic defects in mitochondrial myopathy.
Abstract: Spinocerebellar ataxia 6 (SCA6) is an autosomal dominant spinocerebellar degeneration caused by the expansion of the polymorphic CAG repeat in the human alpha1A voltage-dependent calcium channel subunit gene (CACNL1A4 gene). We have analyzed 60 SCA6 individuals from 39 independent SCA6 Japanese families and found that the CAG repeat length is inversely correlated with the age of onset (n = 58, r = -0.51, P < 0.0001). SCA6 chromosomes contained 21-30 repeat units, whereas normal chromosomes displayed 6-17 repeats. There was no overlap between the normal and affected CAG repeat number. The anticipation of the disease was observed clinically in all eight parent-child pairs that we examined; the mean age of onset was significantly lower (P = 0.0042) in children than in parents. However, a parent-child analysis showed the increase in the expansion of CAG repeats only in one pair and no diminution in any affected cases. This result suggests that factors other than CAG repeats may produce the clinical anticipation. A homozygotic case could not demonstrate an unequivocal gene dosage effect on the age of onset.
Abstract: Coagulation and vascular abnormalities were studied in 4 patients with Crow-Fukase syndrome (CFS or POEMS) to understand the pathophysiology. Fibrinogen, fibrinopeptide A, and thrombin-antithrombin complexes (TAT) increased in sera during active phase of CFS. In nerves of 2 untreated cases, the endothelium of small vessels was immunohistochemically stained with antithrombin III antibody, which indicates the existence of TAT. HLA-DR+ inflammatory cell infiltrate surrounded these vessels. Blood-nerve barrier opening was suggested by strong immunoglobulin staining in the endoneurium. More than 50% of endoneurial blood vessels had narrowed or closed lumina with thick basement membranes. Endothelial cell abnormality and chronic intravascular coagulation may play an important role in the pathogenesis of CFS, in addition to a still unknown demyelinating factor. Refractory cases responded to combined treatment of prednisolone, human leukocyte interferon, and antithrombin drug.
Abstract: We compared the expression of mRNAs for three human glutamate transporter subtypes in human central nervous system (CNS) and other organs by Northern blot analysis. hGLT-1 and hGLuT-1 mRNAs were most abundantly expressed in the brain, while hEAAC1 mRNA expression (3.8 kb and 2,4 kb) was strongest in peripheral organs. All subtype mRNAs were expressed throughout the CNS with hGLT-1 predominant in frontal lobe, striatum and limbic areas, and hGluT-1 predominant in cerebellum.
Abstract: We report a family with Machado-Joseph disease (MJD) that was previously diagnosed with dentatorubral-pallidoluysian atrophy (DRPLA), on the basis of the neuropathologic findings. Because the clinical and pathologic reevaluation strongly suggested a diagnosis of MJD, we conducted a genetic study in the family. Two patients, aged 38 and 40, revealed CAG repeat lengths of the MJD1 gene of 80, 28 and 75, 14, confirming a final diagnosis of MJD.
Abstract: High affinity glutamate transporters regulate levels of extracellular glutamate in the central nervous system. Impaired glutamate transport has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). The glutamate transporter subtypes GluT-1 and EAAC1 have previously been mapped to human chromosomes 5p13 and 9p24, respectively. In the present study, the GLT-1 subtype was mapped to human chromosome 11p11.2-p13 by fluorescence in situ hybridization. The possible clinical implications of this finding are discussed.
Abstract: Hereditary cerebellar ataxias, including spinocerebellar ataxia type I (SCA1), dentato-rubro-pallidoluysian atrophy (DRPLA), and Machado-Joseph disease (MJD), have been associated with unstable CAG repeats. The length of the CAG repeat is a major factor in determining the age of onset of these diseases. In electrophoresis through acrylamide gels with formamide, the CAG repeat length following the polymerase chain reaction (PCR) coincides with the sequence-determined repeat length after subcloning. However, without formamide, PCR products with long CAG repeats appear 1-4 repeats shorter than when electrophoresed with formamide, and the repeat lengths are variable. In addition, the larger the CAG repeats are, the more difficult are the PCR reactions. A mixture containing thermostable Taq and Pwo DNA polymerases (so-called "long PCR") is much more sensitive than that with Taq polymerase alone in detecting- expanded CAG repeats. Therefore, highly denaturing conditions, especially formamide gel electrophoresis, and the "long PCR" protocol should be used to evaluate the exact CAG repeat length. We have used these principles to detect unstable CAG repeats. The normal ranges are 14-34 repeats for MJD, 6-31 repeats for DRPLA, and 21-32 repeats for SCA1.
Abstract: Glutamate transporters play an important role in keeping extracellular glutamate concentrations below the neurotoxic levels. We cloned a human glutamate transporter hGluT-1. In ischemic states, glutamate efflux via glutamate transporters and the extracellular glutamate concentrations are rapidly increased. These phenomenon enlarges the area of neuronal cell death. We showed that L-CCG-III, IV and glutamate block the reverse uptake (efflux) of glutamate in the hGluT-1 expressing HeLa cells. In amyotrophic lateral sclerosis, a glutamate transporter GLT1 was decreased. Decrease of the glutamate transporter will cause the elevation of extracellular glutamate concentrations and will lead to the neuronal injury. Bromocriptine enhances glutamate uptake 1.5 times than in its absence in the hGluT-1 expressing HeLa cells. Enhancing the removal of extracellular glutamate may produce similar effect as those achieved by glutamate-receptor antagonists. At two neuronal death conditions, we showed new possibilities of preventing neuronal cell death by the glutamate transporter regulators.
Abstract: Machado-Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration. The CAG expansions of the MJD1 gene at chromosome 14q32.1 was identified as the cause of the disease. MJD has three factors that influence the age of the onset. The MJD1 repeat length inversely correlated with the age of onset (r = -0.87). Homozygosity of the gene exhibited an additive effect on age of onset. MJD has a gender-specific effect on the age of onset. A parent-child analysis showed the unidirectional expansion of CAG repeats. Among the three clinical subtypes, type I of MJD, with dystonia, showed a larger degree of expansion in CAG repeats of the gene and younger ages of onset than the other types.
Abstract: We cloned a novel basic helix-loop-helix protein, NDRF (NeuroD-related factor), cDNA. NDRF contains 383 amino acids and exhibits 53.4% and 52.2% sequence identity to NeuroD and MATH-2/NEX-1, respectively. NDRF mRNA appears in the brain of 12-day-old mouse embryos and is localized in certain regions of the adult brain, such as the hippocampus, dentate gyrus and cerebellum, Thus, the structure and expression patterns of NDRF are similar to but distinct from those of NeuroD and MATH-2/NEX-1, suggesting that NDRF may play distinct roles in neural development and plasticity as a novel member of the NeuroD family.
Abstract: We cloned two rat cDNAs of brain basic helix-loop-helix factor 1 (BHF1). These have an identical coding region, contain 357 amino acids and exhibit 94.6% identity to MATH-2/NEX1 in the basic helix-loop-helix region. BHF1mRNAs are dominantly expressed in the brain particularly in the cerebellum, in the adult bovine, rat and mouse. Two shorter BHF1mRNAs (1.6 kb and 1.8 kb) were also detected in the mouse embryo, and these decreased in the developmental process. These results suggest that BHF1 may play important roles in cerebellum-specific functions and development of neurons.
Abstract: The effects of isomers of 2-(carboxycyclopropyl)glycine (CCG) on uptake of L-glutamate were investigated in COS-7 cells that expressed a cloned human glutamate transporter (hGluT-1). The (2S, 3S, 4R)-isomer (L-CCG-III) and the (2S, 3R, 4S)-isomer (L-CCG-IV) markedly inhibited glutamate uptake with a 50% inhibitory concentration of 290 nM and 1.1 microM, respectively. The (2S, 3S, 4S)-isomer (L-CCG-I) and the (2S, 3R, 4R)-isomer (L-CCG-II) did not inhibit glutamate uptake at concentrations of < or = 10 microM. Thus, hGluT-1 showed a markedly higher affinity for L-CCG-III and L-CCG-IV with a folded conformation of the glutamate skeleton, than for L-CCG-I or L-CCG-II with an extended conformation.
Abstract: The glutamate transporter takes up glutamate to terminate neurotransmission and to prevent neuronal cell death. Chromosomal location of the human glutamate transporter, hGluT-1, gene (SLC1A3) was determined by fluorescence in situ hybridization. SLC1A3 was mapped to chromosome 5p13.
Abstract: Machado--Joseph disease (MJD) is an autosomal dominant spinocerebellar degeneration mapped to chromosome 14q32.1. The CAG expansions of the MJD1 gene was identified as the cause of the disease. We have analyzed 90 MJD individuals from 62 independent MJD families and found that the MJD1 repeat length is inversely correlated with the age of onset (r = -0.87). The MJD chromosomes contained 61-84 repeat units, whereas normal chromosomes displayed 14-34 repeats. In the normal chromosomes, 14 repeat units were the most common and the shortest. In association with the clinical anticipation of the disease, a parent--child analysis showed the unidirectional expansion of CAG repeats and no case of diminution in the affected family. The differences in CAG repeat length between parent and child and between siblings are greater in paternal transmission than in maternal transmission. Detailed analysis revealed that a large degree of expansion was associated with a shorter length of MJD1 gene in paternal transmission. On the other hand, the increments of increase were similar for shorter and longer expansion in maternal transmission. Among the three clinical subtypes, type I of MJD, with dystonia, showed a larger degree of expansion in CAG repeats of the gene and younger ages of onset than the other types.
Abstract: A complementary DNA clone was isolated from human brain that encodes a glutamate transporter. Injection of RNA transcribed from this cDNA into Xenopus oocytes resulted in expression of a transport activity with a high affinity for glutamate (Km = 78.4 microM) and a dependency on external Na+. The cDNA sequence predicts a protein of 542 amino acids that is highly homologous to the congeneric proteins from rat and mouse brains. RNA blotting analyses revealed the expression both in the brain and in peripheral tissues.
Abstract: We have identified a novel gene containing CAG repeats and mapped it to chromosome 14q32.1, the genetic locus for Machado-Joseph disease (MJD). In normal individuals the gene contains between 13 and 36 CAG repeats, whereas most of the clinically diagnosed patients and all of the affected members of a family with the clinical and pathological diagnosis of MJD show expansion of the repeat-number (from 68-79). Southern blot analyses and genomic cloning demonstrates the existence of related genes. These results raise the possibility that similar abnormalities in related genes may give rise to diseases similar to MJD.
Abstract: The effect of ciliary neurotrophic factor (CNTF) on beta-amyloid precursor protein (APP) gene expression was investigated in cultured rat C6 glioma cells and human SH-SY5Y neuroblastoma cells. CNTF increased APP mRNA abundance in C6 glioma cells in a dose-dependent manner, with an approximately 3-fold increase in maximum observed after 24 h with a concentration of 1 ng/ml. However, no significant differences in the splicing pattern of the three major isoforms of APP mRNA were apparent between control and CNTF-treated C6 glioma cells. CNTF had no effect on APP mRNA abundance in SH-SY5Y neuroblastoma cells. These findings suggest that CNTF can modulate APP mRNA expression and might affect amyloidogenesis in Alzheimer's disease.
Abstract: The distribution of HLA-A, B, C, DR and DRB1, DQB1, DPB1 alleles was studied in 60 Japanese patients with clinically definite multiple sclerosis (MS) using serologic and genomic analysis. We found significant associations with HLA-Cw3 (p = 0.002, pc = 0.012, RR = 3.2), DR2 (p = 0.007, RR = 2.6), and DQB1*0602 (p = 0.04, RR = 4.0) in Japanese patients for the first time. The combined presence of Cw3 and DR2 gave a higher risk than each antigen alone. The reported increase in the frequency of DPw4 in Japanese MS patients [12] could not be confirmed by our genomic study. The frequencies of all of the residues in each variable region of the amino acid sequences of DQ beta and DP beta chains were not different between the MS patients and the controls. These results suggest that MS susceptibility may result from polygenic influences and from the presence of environmental factors.
Abstract: Brush border myosin I heavy chain (MIHC), known previously as the brush border 110-kDa protein, contains an amino-terminal sequence which is highly homologous to the globular head domain of conventional myosin II heavy chain (MIIHC). The carboxyl-terminal sequence of MIHC completely diverges from that of MIIHC and functions as calmodulin-binding and membrane-interaction sites. In this investigation, we determined the structural organization of the bovine MIHC by isolating a set of genomic segments containing the whole MIHC gene. The bovine MIHC gene is 26 kilobase pairs long and consists of 28 exons. At the homologous amino-terminal portion of MIHC, many introns are located at positions equivalent to those of the rat MIIHC gene and the amoeba MIHC gene. At the carboxyl-terminal sequence of MIHC, the putative calmodulin-binding and membrane-interacting domains are specified by discrete sets of exons. These findings support the view that the amino-terminal head portions of MIHC and MIIHC evolved from a common ancestral origin and also that the MIHC protein was generated as a result of fusion of discrete genomic segments encoding different functional and structural protein domains. Analysis of tissue expression of the MIHC mRNA was also extended in this investigation, and the results indicated that this mRNA is expressed in some tissues other than the intestines.
Abstract: The role of the renin-angiotensin system in blood pressure control and in the development of hypertension was investigated by generating transgenic mice carrying the rat renin or angiotensinogen gene or both genes under the control of the mouse metallothionein I promoter. The systolic blood pressure was significantly elevated in transgenic mice carrying both transgenes but was maintained normally in those bearing either of the transgenes. The transgene was effectively and properly transcribed to form the mature mRNA in the transgenic mice. The production of rat renin and angiotensinogen in the transgenic mice carrying the corresponding transgene was also verified by immunoanalyses of these proteins. Furthermore, the specific angiotensin-converting enzyme inhibitor captopril was effective in reducing the elevated blood pressure of the hypertensive transgenic mice. These results indicate that the combined action of the exogenous rat renin and angiotensinogen is responsible and necessary for elevation of blood pressure in the hypertensive transgenic mice.
