Mitsuteru Shimohata

SCA17 homozygote showing Huntington's disease‐like phenotype

We report a homozygous case of spinocerebellar ataxia type 17 with 48 glutamines. The age of the patient at disease onset was not lower than those of heterozygotes with the same CAG‐repeat sizes, but the clinical manifestations were rapidly progressive dementia and chorea. Neuronal loss was relatively restricted and most prominent in the Purkinje cell layer and striatum; however, intranuclear neuronal polyglutamine accumulation was widespread, with a high frequency in the cerebral cortex and striatum.

Periaxin mutation causes early-onset but slow-progressive Charcot-Marie-Tooth disease

AbstractPeriaxin (PRX) plays a significant role in the myelination of the peripheral nerve. To date, seven nonsense or frameshift PRX mutations have been reported in six pedigrees with Dejerine-Sottas neuropathy or severe Charcot-Marie-Tooth neuropathy (CMT). We detected a PRX mutation in three patients in the screening of 66 Japanese demyelinating CMT patients who were negative for the gene mutation causing dominant or X-linked demyelinating CMT. Three unrelated patients were homozygous for a novel R1070X mutation and presented early-onset but slowly progressive distal motor and sensory neuropathies. Mutations lacking the carboxyl-terminal acidic domain may show loss-of-function effects and cause severe demyelinating CMT.

Polyglutamine disease: recent advances in the neuropathology of dentatorubral-pallidoluysian atrophy.

Polyglutamine diseases are hereditary neurodegenerative disorders that are caused by the expansion of a CAG repeat in the causative genes. They comprise at least nine disorders, including DRPLA, HD, and Machado‐Joseph disease. Initially, the discovery of neuronal intranuclear inclusions (NIIs) in human brains and in a murine model of HD provided a plausible hypothesis that the expression of expanded polyglutamine stretches leads to NII formation, resulting in neuronal cell death in selective brain regions characteristic to each disease. Recent studies, however, suggest that nuclear dysfunction, especially transcriptional abnormalities caused by the diffuse intranuclear accumulation of mutant proteins, plays a pivotal role in the development and progression of clinical symptoms. Polyglutamine diseases have a similarity with neuronal storage disease, and this pathological process might become a target for the establishment of an effective therapy for these diseases.

Interference of CREB-dependent transcriptional activation by expanded polyglutamine stretches - augmentation of transcriptional activation as a potential therapeutic strategy for polyglutamine diseases

On the basis of the hypothesis that the interaction of mutant proteins with expanded polyglutamine stretches with transcriptional co‐activator, TAFII130, leads to transcriptional dysregulation, the transcriptional activation of c‐Fos and its suppression by expanded polyglutamine stretches was investigated. The phosphorylation of cAMP‐responsive element binding protein (CREB) and induction of c‐Fos in response to cAMP were strongly suppressed in Neuro2a cells expressing expanded polyglutamine. The suppression of CREB‐dependent transcriptional activation was reversibly rescued by increasing the concentration of cAMP. Expanded polyglutamine‐induced cytotoxicity was also substantially suppressed by augmenting CREB‐dependent transcriptional activation with a high concentration of cAMP. FR901228, a histone deacetylase inhibitor, was also demonstrated as rescuing the expanded polyglutamine‐induced suppression of CREB phosphorylation and c‐Fos expression. Furthermore, nuclear fragmentation was significantly suppressed by FR901228. The co‐expression of dominant‐negative CREB vectors considerably abrogated the suppressive effect of cAMP and FR901228 on the expanded polyglutamine‐induced nuclear fragmentation, suggesting that these compounds suppress polyglutamine‐induced cytotoxicity, largely, via the enhancement of CREB‐dependent transcriptional activation. These findings suggest that the interference of CREB‐dependent transcriptional activation by expanded polyglutamine stretches is involved in the pathogenetic mechanisms underlying neurodegeneration, and that the augmentation of CREB‐dependent transcriptional activation is a potential strategy in treating polyglutamine diseases.

Spinocerebellar ataxia type 2 (SCA2) is associated with TDP-43 pathology

Abnormality of the nuclear protein TDP-43 is associated with amyotrophic lateral sclerosis (ALS), a usually sporadic, fatal neurological disease. Recently, the yeast ortholog of ataxin 2, Pbp 1, was shown to enhance the toxicity of TDP-43 [1], and ataxin 2 intermediate-length polyglutamine (polyQ) expansions were found to be associated with ALS [1, 2]. Ataxin 2 is a polyQ protein that is mutated in spinocerebellar ataxia type 2 (SCA2), an autosomal-dominant neurological disease, by an expansion of CAG repeats in the SCA2 gene (ATXN2). In the present study, we performed an immunohistochemical examination of phosphorylated TDP-43 (pTDP43), the pathological form of TDP-43, in various regions of the brain and spinal cord in a patient with SCA2. We found that pTDP-43 neuronal cytoplasmic inclusions (NCIs), although small in number in individual regions, occurred widely in the central nervous system (CNS), except the lower motor neuron system. Examination of the patient’s family history revealed a similar neurological disease that had affected the mother, whose initial symptom had been cerebellar ataxia at the age of 47 years and who had died at the age of 59 years, and the patient’s elder brother, who was still alive at the age of 56 years after initially developing gait disturbance at the age of 41 years. The patient, a Japanese man, had developed speech disturbance as the initial symptom in his 30 s. At the age of 46 years, he had been diagnosed as having SCA2 by DNA examination; the number of CAG repeats in ATXN2 was 42. At the age of 50 years, he was admitted to our hospital with nystagmus and severe cerebellar deficit involving the arms and legs. About 1 year later, he also became diabetic. Thereafter, his general condition worsened gradually, and he died of liver dysfunction at the age of 52 years. The brain weighed 1,005 g (brainstem and cerebellum, 100 g) before fixation. The pontine base and cerebellum showed marked atrophy (Fig. 1a). Mild atrophy was also evident in the frontal lobe, including the precentral gyrus. In sections, severe atrophy of the brainstem and cerebellum was confirmed; the substantia nigra showed severe depigmentation (Fig. 1b). Histologically, neuronal loss was evident in the motor cortex (Fig. 1c) and spinal anterior horns (Fig. 1d). No Bunina bodies were present in the lower motor neurons. Atrophy and myelin pallor were evident in the spinal posterior column. Immunostaining with 1C2, an antibody specific for polyQ stretches (monoclonal; Chemicon, Temecula, CA, USA), revealed many widely distributed positive neuronal inclusions in the CNS (Fig. 2a). These inclusions were present frequently in the cytoplasm (Fig. 2b) and rarely in the nuclei (Fig. 2c). Immunostaining with an antibody against pTDP-43 (monoclonal, pS409/410; Cosmo Bio, Tokyo, Japan) also revealed positive NCIs appearing as linear wisp-like, skein-like (Fig. 2d), or dense bodies. Cat’s eye-shaped neuronal intranuclear inclusions (NIIs) were also observed in a few neurons (Fig. 2e). pTDP-43-positive Y. Toyoshima (&) A. Kakita H. Takahashi Department of Pathology, Brain Research Institute, University of Niigata, 1-757 Asahimachi, Chuo-ku, Niigata 951-8585, Japan e-mail: yasuko@bri.niigata-u.ac.jp

Periaxin mutation in Japanese patients with Charcot-Marie-Tooth disease

AbstractPeriaxin (PRX) plays an important role in the myelination of the peripheral nerve and consequently in the pathogenesis of Charcot-Marie-Tooth disease (CMT). To date, nine nonsense or frameshift PRX mutations have been reported in eight families with CMT. The patients with PRX mutations appeared to show characteristic clinical features with early onset but slow or no progression, a common result of mutations that lead to missing a C-terminal acidic domain. Here, we report a Japanese CMT patient with these characteristic clinical features, who was a compound heterozygote for PRX R1070X and L132FsX153 mutations. We previously reported that three Japanese isolated families also had the homozygous R1070X mutation. To examine the potential founder effect of the R1070X mutation in the Japanese population, we performed haplotype analysis and found that each R1070X allele lay on a different haplotype background in these four families. Therefore, the high frequency of the R1070X mutation among the Japanese population is not likely the consequence of a founder effect, but probably a result of a mutation hot spot.

Transportin 1 accumulates in FUS inclusions in adult-onset ALS without FUS mutation.

Accumulation of a protein, DNA/RNA binding protein fused in sarcoma (FUS), as cytoplasmic inclusions in neurones and glial cells in the central nervous system (CNS) is the pathological hallmark of amyotrophic lateral sclerosis (ALS) with FUS mutations (ALS-FUS) [1,2] as well as certain subtypes of frontotemporal lobar degeneration (FTLD-FUS) [3,4], the latter being unassociated with FUS mutations. While the inclusions in ALS-FUS contain only FUS, those in FTLD-FUS show co-accumulation of three proteins of the FET protein family, i.e. in addition to FUS, Ewing’s sarcoma (EWS) and TATA-binding proteinassociated factor 15 (TAF15) [5]. These findings strongly suggest that a more complex derangement of transportinmediated nuclear import of proteins accounts for the disease process in FTLD-FUS in comparison to ALS-FUS. Recently, Neumann et al. reported that the inclusions in FTLD-FUS subtypes were strongly labelled for transportin 1 (TRN1) and that, as expected, the inclusions in ALS-FUS were completely unreactive for this protein [6]. Here we report an adult patient who exhibited a clinically pure ALS phenotype without FUS mutations (ALS-FUS) and cytoplasmic inclusions showing coaccumulation of FET and TRN1 proteins, confirming that ALS-FUS and FTLD-FUS represent part of a spectrum of FUS proteinopathy without FUS mutation. A 65-year-old Japanese woman became aware of muscle weakness in her hands. Three years later, she was diagnosed as having ALS. Thereafter, bulbar palsy and respiratory distress progressed gradually; at the age of 70 years, tracheotomy and respirator support became necessary. The patient died of gastrointestinal bleeding at the age of 74 years, about 9 years after disease onset. There was no family history of neurological disorders, including ALS. During the disease course, dementia was not evident. We sequenced and found no mutations in the all coding regions of the FUS gene. The brain was small and weighed 820 g (brainstem and cerebellum, 110 g) before fixation. The spinal cord showed marked atrophy. Histologically, loss of myelinated fibres was observed in the spinal white matter except for the posterior columns; the lateral corticospinal tracts appeared to be only mildly affected (Figure 1a). Neuronal loss and gliosis were also evident in the spinal anterior horns (Figure 1b) and brainstem hypoglossal nucleus. The presence of slightly basophilic round inclusions in the remaining lower motor neurones was a feature (Figure 1c). No Bunina bodies were found. In the cerebral cortex, mild neuronal loss was noted in the motor cortex. Immunostaining with an antibody against FUS (polyclonal, SigmaAldrich, St Louis, USA; 1:50) revealed widely distributed positive neuronal cytoplasmic inclusions (NCIs) in the CNS, including the spinal anterior horn and motor cortex (Figure 1d,e). The distribution and severity of FUS lesions and neuronal loss are shown inTable 1. FUS immunostaining also revealed positive glial cytoplasmic inclusions (GCIs) (Figure 1f). These cytoplasmic inclusions were also labelled by anti-ubiquitin (polyclonal, Dako, Glostrup, Denmark; 1:800) (Figure 1g) and anti-p62 (monoclonal; BD Bioscience, San Jose, CA, USA; 1:1000) antibodies (Figure 1h). No neuronal nuclear inclusions (NIIs) were found.The results of immunostaining for a-internexin and TDP-43 were all negative (data not shown). Immunostaining with an antibody against transportin 1 (TRN1) (monoclonal, Abcam, Cambridge, UK; 1:200) also revealed clearly positive NCIs (Figure 2a) and GCIs. Such inclusions were also labelled with anti-TAF15 (polyclonal, Bethyl Lab, Montgomery, USA; 1:200) (Figure 2b) and anti-EWS (monoclonal, Santa Cruz, Santa Cruz, USA; 1:200) antibodies (Figure 2c). TRN1 and FUS were sometimes fully or partially colocalized in the same neurones (Figure 2d–f,g–i) and glial cells. The ratio of the colocalization (TRN1/FUS) in NCIs was about 50%. FTLD-FUS can be classified into three pathological subtypes, atypical FTLD-U, neuronal intermediate filament inclusion disease (NIFID), and basophilic inclusion body disease (BIBD) on the basis of the morphology and distribution pattern of FUS-positive NCIs and NIIs [3]. Atypical FTLD-U is characterized by compact, round to oval kidneyshaped NCIs and vermiform NIIs in the neocortex, granule cells of the dentate gyrus, striatum and some other brain regions. NIFID is characterized by FUS-positive NCIs and NIIs as well as less predominant type IV interfilament-, a-internexinand neurofilament-positive NCIs. Lastly,

Cerebral lipoma and the underlying cortex of the temporal lobe: pathological features associated with the malformation

Intracranial lipomas are believed to be congenital malformations rather than true neoplasms, resulting from the abnormal differentiation of the meninx primitiva, the undifferentiated mesenchyme. We report here the surgical pathological features of a lipoma that was located on the cerebral surface of an abnormally formed fissure, and the underlying cortex of the middle temporal gyrus of a 20-year-old woman. The mass was composed of typical adipose tissue in which a large number of blood vessels were present. Thick connective tissue associated with the arachnoid membrane covered the cortical surface. The cortex exhibited a polymicrogyric configuration in which the cortical ribbon was abnormally undulated and excessively folded. Reelin-immunolabeled Cajal-Retzius-cell-like cells were observed frequently in the fused molecular layer. The cortical lamination underlying the molecular layer was poorly defined. Along the border between the connective tissue and cortical surface, there was a narrow zone in which the mesenchymal and neuronal tissues were intermingled, and where immunohistochemical and ultrastructural investigations disclosed disruption of the basal lamina, prominent astrocytosis, and abundant axonal and synaptic profiles. These findings suggest that focal disturbances in cerebral cortical development occur in association with the development of lipomas.

Numbness in the tip of the tongue and lower lip caused by thalamic hemorrhage.

Although patients with isolated oral syndrome or facial sensory loss following stroke of thalamic ventroposteromedial (VPM) nucleus have been reported, there have been no reports of numbness in the tip of the tongue and lower lip. Furthermore, symptoms in the tip of the tongue caused by stroke are typically characterized as gustatory sensory disturbances. A 62-year-old hypertensive man experienced an acute onset of severe numbness in the left tip of the tongue and ipsilateral lower lip. Neurological examination revealed no other abnormalities except for the aforementioned numbness. Head computed tomography showed a small hematoma in the medial part of the right thalamus, most likely within the VPM nucleus. The somatosensory impulse of the tongue is conveyed via the lingual nerve, and it reaches the contralateral medial VPM proper via the trigeminal spinal nucleus. Therefore, thalamic stroke mainly involving the medial VPM proper has the potential to elicit numbness in the tip of the tongue. A major portion of the VPM nucleus is vascularized by the inferolateral arteries. The inferolateral arteries vary greatly in the number and position of the arteries and their tributaries, and small-vessel disease in this territory can present with diverse symptoms because of this complexity. These findings indicate that central neurological involvement should not be overlooked in the case of sensory disturbance restricted to the tip of the tongue and lip.