Takahiro Kano

Clinical, pathological, and genetic mutation analysis of sporadic inclusion body myositis in Japanese people

Previous studies have identified several genetic loci associated with the development of familial inclusion body myopathy. However, there have been few genetic analyses of sporadic inclusion body myositis (sIBM). In order to explore the molecular basis of sIBM and to investigate genotype-phenotype correlations, we performed a clinicopathological analysis of 21 sIBM patients and screened for mutations in the Desmin, GNE, MYHC2A, VCP, and ZASP genes. All coding exons of the five genes were sequenced directly. Definite IBM was confirmed in 14 cases, probable IBM in three cases, and possible IBM in four cases. No cases showed missense mutations in the Desmin, GNE, or VCP genes. Three patients carried the missense mutation c.2542T>C (p.V805A) in the MYHC2A gene; immunohistochemical staining for MYHC isoforms in these three cases showed atrophy or loss of muscle fibers expressing MYHC IIa or IIx. One patient harbored the missense mutation c.1719G>A (p.V566M) in the ZASP gene; immunohistochemical studies of Z-band-associated proteins revealed Z-band abnormalities. Both of the novel heterogeneous mutations were located in highly evolutionarily conserved domains of their respective genes. Cumulatively, these findings have expanded our understanding of the molecular background of sIBM. However, we advocate further clinicopathology and investigation of additional candidate genes in a larger cohort.

TRIM67 protein negatively regulates Ras activity through degradation of 80K-H and induces neuritogenesis.

Background: TRIM67, which is selectively expressed in the cerebellum, is a novel member of the TRIM protein family. Results: TRIM67 interacts with PRG-1 and 80K-H, which is involved in the Ras-mediated signaling pathway. Conclusion: TRIM67 regulates Ras signaling via degradation of 80K-H, leading to neural differentiation including neuritogenesis. Significance: Analysis of TRIM67 would provide therapeutic benefits for neurodegenerative diseases. Tripartite motif (TRIM)-containing proteins, which are defined by the presence of a common domain structure composed of a RING finger, one or two B-box motifs and a coiled-coil motif, are involved in many biological processes including innate immunity, viral infection, carcinogenesis, and development. Here we show that TRIM67, which has a TRIM motif, an FN3 domain and a SPRY domain, is highly expressed in the cerebellum and that TRIM67 interacts with PRG-1 and 80K-H, which is involved in the Ras-mediated signaling pathway. Ectopic expression of TRIM67 results in degradation of endogenous 80K-H and attenuation of cell proliferation and enhances neuritogenesis in the neuroblastoma cell line N1E-115. Furthermore, morphological and biological changes caused by knockdown of 80K-H are similar to those observed by overexpression of TRIM67. These findings suggest that TRIM67 regulates Ras signaling via degradation of 80K-H, leading to neural differentiation including neuritogenesis.

Identification of anti-Sez6l2 antibody in a patient with cerebellar ataxia and retinopathy

Cerebellar ataxia (CA) is one of the main syndromes of both central nervous system syndrome associated with neuronal surface antibodies and paraneoplastic neurological diseases [5]. Some antigens of anti-neuronal antibodies have been reported, and their detection has contributed to the establishment of the disease concept and treatment strategy [1]. In the present study, in order to identify novel anti-neuronal antibodies and the corresponding autoantigens, we examined sera from six patients assumed to have immune-mediated cerebellar ataxia for immunoreactivity against the mouse cerebellum. To find a specific antigen that is recognized by sera from six patients with CA, which was assumed to be associated with an immune-mediated mechanism, and control sera, we performed immunoblotting analysis with sera using lysates from the mouse cerebellum. We found that a protein of approximately 170 kDa was detected by the serum of a patient with CA and retinopathy (CAR), which we named CAR protein. The CAR protein was not detected by sera from the other five CA patients, six controls, five multiple system atrophy patients, one Parkinson’s disease patient, one amyotrophic lateral sclerosis patient, one neuromyelitis optica patient, or one tumefactive multiple sclerosis patient (Fig. 1a). The patient is a 60-year-old woman who developed CA. Her symptoms worsened rapidly over a period of about 3 months. A neurological examination on admission revealed severe cerebellar ataxia and retinopathy. The results of blood tests, including tests for autoantibodies and anti-neuronal antibodies (VGCC, Hu, Yo, Ri, GAD, GQ1b, GM1, gliadin and recoverin) were normal. Screening for malignant tumors was negative. The results of a cerebrospinal fluid test were normal. Magnetic resonance (MR) imaging of the brain showed no abnormality (Fig. 1b). H. Yaguchi and I. Yabe contributed equally to this article.

Level of plasma neuregulin-1 SMDF is reduced in patients with idiopathic Parkinson’s disease

Parkinsons disease (PD) is characterised by the progressive loss of dopaminergic neurons, neurons that are regulated by the development, protection and function of neuregulin-1 (NRG1)-ErbB4 signals, in the substantia nigra (SN). NRG1 is a neurotrophic differentiation factor and one of its isoforms is a sensory and motor neuron-derived factor (SMDF), mostly expressed in neurons. To examine the relationship between NRG1 SMDF and PD, we tested whether NRG1 SMDF can be detected and measured in plasma and whether their level in plasma correlates with the clinical severity of PD. We detected NRG1 SMDF to be immunoreactive in plasma. Using an ELISA method specific for NRG1 SMDF, we found that NRG1 SMDF levels were significantly reduced in sporadic PD as compared to controls. However, levels of plasma NRG1 SMDF showed no correlation with the clinical severity of PD. Additionally, we found that there was a correlation of NRG1 SMDF levels in CSF with that in plasma where levels in plasma were significantly higher, at approximately ten times that in CSF. Finally, we also examined the expression of NRG1 SMDF in the post-mortem brain using immunohistochemistry and showed that Lewy bodies in the SN of patients with PD were immunoreactive for NRG1 SMDF. In summary, we found that the reduction of plasma NRG1 SMDF is specifically associated with PD, but has no correlation with the clinical severity of PD. These findings of NRG1 SMDF may provide important complementary information for diagnosing the onset of PD.

Validity and reliability of a pilot scale for assessment of multiple system atrophy symptoms

BackgroundMultiple system atrophy (MSA) is a rare progressive neurodegenerative disorder for which brief yet sensitive scale is required in order for use in clinical trials and general screening. We previously compared several scales for the assessment of MSA symptoms and devised an eight-item pilot scale with large standardized response mean [handwriting, finger taps, transfers, standing with feet together, turning trunk, turning 360°, gait, body sway]. The aim of the present study is to investigate the validity and reliability of a simple pilot scale for assessment of multiple system atrophy symptoms.MethodsThirty-two patients with MSA (15 male/17 female; 20 cerebellar subtype [MSA-C]/12 parkinsonian subtype [MSA-P]) were prospectively registered between January 1, 2014 and February 28, 2015. Patients were evaluated by two independent raters using the Unified MSA Rating Scale (UMSARS), Scale for Assessment and Rating of Ataxia (SARA), and the pilot scale. Correlations between UMSARS, SARA, pilot scale scores, intraclass correlation coefficients (ICCs), and Cronbach’s alpha coefficients were calculated.ResultsPilot scale scores significantly correlated with scores for UMSARS Parts I, II, and IV as well as with SARA scores. Intra-rater and inter-rater ICCs and Cronbach’s alpha coefficients remained high (> 0.94) for all measures.ConclusionThe results of the present study indicate the validity and reliability of the eight-item pilot scale, particularly for the assessment of symptoms in patients with early state multiple system atrophy.

Novel GNE compound heterozygous mutations in a GNE myopathy patient.

Introduction: Molecular studies have revealed that some patients with myopathies with rimmed vacuoles have pathogenic mutations in the UDP‐N‐acetylglucosamine‐2‐epimerase/N‐acetylmannosamine kinase (GNE) and Z‐band alternatively spliced PDZ motif‐containing protein (ZASP) genes. Methods: We investigated a patient with distal myopathy with rimmed vacuoles by muscle biopsy and sequenced 6 candidate genes. Results: The patient carried GNE compound heterozygous missense mutations (p.V421A and p.N635K) and a ZASP variant (p.D673N). This patient also presented with distal weakness sparing the quadriceps muscles and had atypical results for Z‐band‐associated protein immunostaining. This finding indicates that the GNE mutations are pathogenic, and the diagnosis is compatible with GNE myopathy. Conclusions: By combining pathological studies and candidate gene screening, we identified a patient with GNE myopathy due to novel GNE compound heterozygous mutations. Muscle Nerve 48: 594–598, 2013

Usefulness of 11C-methionine-positron emission tomography for the diagnosis of progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a subacute demyelinating disease of the brain caused by the JC virus that occurs mainly in immunocompromised patients. The prognosis is very poor. As the lesion looks like non- specific leukoencephalopathy, making a diagnosis at the early stage is very difficult. We report three PML cases in which there was a mismatch between 11C-methionine-positron emission tomography (MET-PET) uptake and 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) uptake. All three cases demonstrated the hyper-uptake of MET around the white matter lesions and hypo-uptake of FDG inside the lesions. We speculate that the infection had ended inside the white matter lesions of these patients, while JC virus infection was ongoing around the lesions, resulting in the increase of methionine metabolism, and the glucose metabolism was reduced or intermediate because inflammatory cells infiltrate PML lesions rarely. Two patients who were diagnosed and treated with mefloquine while the JC virus was at a low level in the cerebrospinal fluid are still alive. We suggest the usefulness of MET-PET for the early diagnosis of PML and early treatment with mefloquine.

Reliability of the Japanese version of the scales for outcomes in Parkinson's disease-autonomic questionnaire.

OBJECTIVE The Scales for Outcomes in Parkinsons Disease-Autonomic (SCOPA-AUT) questionnaire was used to assess autonomic dysfunction in patients with neurological disorders. The aim of this study was to evaluate the reliability of the Japanese version of the SCOPA-AUT. METHODS We translated the SCOPA-AUT from English to Japanese. Thirty-one patients with diseases involving autonomic symptoms completed the form twice. The reliability was assessed by Cronbachs coefficient alphas and intraclass correlation coefficients (ICCs). RESULTS The average (standard deviation, SD) total scores of the first and second assessments of the SCOPA-AUT were 15.7 (SD, 7.1) and 13.6 (SD, 6.5), respectively. The Cronbachs coefficient alphas were globally high, but the ICCs were moderately high. The valid response rates for the questions about sexual dysfunction were 36.7% in men and 26.6% in women. CONCLUSIONS The Japanese version of the SCOPA-AUT had high internal consistency. However, the questions about sexual dysfunction showed less valid response rates.

Sez6l2 regulates phosphorylation of ADD and neuritogenesis

Increasing evidence shows that immune-mediated mechanisms may contribute to the pathogenesis of central nervous system disorders including cerebellar ataxias, as indicated by the aberrant production of neuronal surface antibodies. We previously reported a patient with cerebellar ataxia associated with production of a new anti-neuronal antibody, anti-seizure-related 6 homolog like 2 (Sez6l2). Sez6l2 is a type 1 membrane protein that is highly expressed in the hippocampus and cerebellar cortex and mice lacking Sez6l2 protein family members develop ataxia. Here we used a proteomics-based approach to show that serum derived from this patient recognizes the extracellular domain of Sez6l2 and that Sez6l2 protein binds to both adducin (ADD) and glutamate receptor 1 (GluR1). Our results indicate that Sez6l2 is one of the auxiliary subunits of the AMPA receptor and acts as a scaffolding protein to link GluR1 to ADD. Furthermore, Sez6l2 overexpression upregulates ADD phosphorylation, whereas siRNA-mediated downregulation of Sez612 prevents ADD phosphorylation, suggesting that Sez6l2 modulates AMPA-ADD signal transduction.

Effectiveness of zonisamide in a patient with Parkinson's disease and various levodopa‐induced psychotic symptoms

Levodopa and dopamine agonists are useful as Parkinsons disease medications. However, they often induce persistent psychotic symptoms and motor complications, which make Parkinsons disease treatment difficult. This is a case report of a patient with advanced Parkinsons disease accompanied by exacerbation of motor symptoms and psychotic symptoms derived from prolonged use of conventional anti‐Parkinsons disease drugs, and in whom adjunctive therapy with a new anti‐Parkinsons disease drug, zonisamide, was shown to improve motor symptoms with no exacerbation of psychotic symptoms.