Tau filaments from amyotrophic lateral sclerosis/parkinsonism-dementia complex adopt the CTE fold.

The amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of the island of Guam and the Kii peninsula of Japan is a fatal neurodegenerative disease of unknown cause that is characterized by the presence of abundant filamentous tau inclusions in brains and spinal cords. Here, we used electron cryo-microscopy to determine the structures of tau filaments from the cerebral cortex of three cases of ALS/PDC from Guam and eight cases from Kii, as well as from the spinal cord of two of the Guam cases. Tau filaments had the chronic traumatic encephalopathy (CTE) fold, with variable amounts of Type I and Type II filaments. Paired helical tau filaments were also found in three Kii cases and tau filaments with the corticobasal degeneration fold in one Kii case. We identified a new Type III CTE tau filament, where protofilaments pack against each other in an antiparallel fashion. ALS/PDC is the third known tauopathy with CTE-type filaments and abundant tau inclusions in cortical layers II/III, the others being CTE and subacute sclerosing panencephalitis. Because these tauopathies are believed to have environmental causes, our findings support the hypothesis that ALS/PDC is caused by exogenous factors.

Protein profiling of extracellular vesicles from iPSC-derived astrocytes of patients with ALS/PDC in Kii peninsula.

BACKGROUND: Amyotrophic lateral sclerosis/Parkinsonism-dementia complex in Kii peninsula, Japan (Kii ALS/PDC), is an endemic neurodegenerative disease whose causes and pathogenesis remain unknown. However, astrocytes in autopsied cases of Kii ALS/PDC show characteristic lesions. In addition, relationships between extracellular vesicles (EVs) and neurodegenerative diseases are increasingly apparent. Therefore, we focused on proteins in EVs derived from Kii ALS/PDC astrocytes in the present study. METHODS: Induced pluripotent stem cells (iPSCs) derived from three healthy controls (HCs) and three patients with Kii ALS/PDC were differentiated into astrocytes. EVs in the culture medium of astrocytes were collected and subjected to quantitative proteome analysis. RESULTS: Our proteome analysis reveals that EV-containing proteins derived from astrocytes of patients with Kii ALS/PDC show distinctive patterns compared with those of HCs. Moreover, EVs derived from Kii ALS/PDC astrocytes display increased proteins related to proteostasis and decreased proteins related to anti-inflammation. DISCUSSION: Proteins contained in EVs from astrocytes unveil protective support to neurons and may reflect the molecular pathomechanism of Kii ALS/PDC; accordingly, they may be potential biomarker candidates of Kii ALS/PDC.

An immigrant family with Kii amyotrophic lateral sclerosis/parkinsonism-dementia complex.

OBJECTIVES: Amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a unique endemic on Guam island of the USA, the Kii Peninsula of Japan, and Papua state of Indonesia. The pathomechanism of ALS/PDC remains to be solved, although interaction between some environmental factors and genetic background is plausible. This is the first autopsy-proven immigrant family of ALS/PDC of the Kii Peninsula. METHODS: A daughter and her father immigrated to the high incident area from outside the Kii Peninsula. The father developed ALS 18 years later after immigration, and his daughter also developed ALS 65 years after immigration. They showed pure ALS phenotype without parkinsonism and dementia. RESULTS: The daughter was diagnosed neuropathologically with Kii ALS/PDC with multiple proteinopathies: tauopathy, α-synucleinopathy, and TDP-43 proteinopathy. Gene analysis of familial ALS-related genes, including C9orf72, showed no mutation. DISCUSSION: The findings in an immigrant family established that certain environmental factors play a critical role in the pathogenesis of Kii ALS/PDC.

EF hand-like motif mutations of Nav1.4 C-terminus cause myotonic syndrome by impairing fast inactivation.

INTRODUCTION: Mutations of the voltage-gated sodium channel gene (SCN4A), which encodes Nav1.4, cause nondystrophic myotonia that occasionally is associated with severe apnea and laryngospasm. There are case reports of nondystrophic myotonia due to mutations in the C-terminal tail (CTerm) of Nav1.4, but the functional analysis is scarce. METHODS: We present two families with nondystrophic myotonia harboring a novel heterozygous mutation (E1702del) and a known heterozygous mutation (E1702K). RESULTS: The proband with E1702K exhibited repeated rhabdomyolysis, and the daughter showed laryngospasm and cyanosis. Functional analysis of the two mutations as well as another known heterozygous mutation (T1700_E1703del), all located on EF hand-like motif in CTerm, was conducted with whole-cell recording of heterologously expressed channel. All mutations displayed impaired fast inactivation. DISCUSSION: The CTerm of Nav1.4 is vital for regulating fast inactivation. The study highlights the importance of accumulating pathological mutations of Nav1.4 and their functional analysis data.

Comparison of Premortem Magnetic Resonance Imaging and Postmortem Autopsy Findings of a Cortical Microinfarct.

An 85-year-old woman diagnosed with amyotrophic lateral sclerosis died of pneumonia and was autopsied. Magnetic resonance imaging (MRI) performed 16 days before death revealed an intracortical high-intensity lesion in her right temporal cortex on three-dimensional (3D)-double inversion recovery (DIR) and 3D-fluid-attenuated inversion recovery (FLAIR) images. Histopathological examination indicated a cortical microinfarct (CMI) juxtaposed to cerebral amyloid angiopathy. Recently, in vivo detection of CMIs using 3D-DIR and 3D-FLAIR on 3-tesla MRI has been reported, and postmortem MRI study confirmed the presence of CMIs. This is the first case study to compare CMI findings detected upon premortem MRI to the CMI itself discovered upon postmortem neuropathological examination.

Tau Filaments from Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex (ALS/PDC) adopt the CTE Fold.

The amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of the island of Guam and the Kii peninsula of Japan is a fatal neurodegenerative disease of unknown cause that is characterised by the presence of abundant filamentous tau inclusions in brains and spinal cords. Here we used electron cryo-microscopy (cryo-EM) to determine the structures of tau filaments from the cerebral cortex of three cases of ALS/PDC from Guam and eight cases from Kii, as well as from the spinal cord of two of the Guam cases. Tau filaments had the chronic traumatic encephalopathy (CTE) fold, with variable amounts of Type I and Type II filaments. Paired helical tau filaments were also found in two Kii cases. We also identified a novel Type III CTE tau filament, where protofilaments pack against each other in an anti-parallel fashion. ALS/PDC is the third known tauopathy with CTE-type filaments and abundant tau inclusions in cortical layers II/III, the others being CTE and subacute sclerosing panencephalitis. Because these tauopathies are believed to have environmental causes, our findings support the hypothesis that ALS/PDC is caused by exogenous factors.

Endemic parkinsonism: clusters, biology and clinical features.

The term 'endemic parkinsonism' refers to diseases that manifest with a dominant parkinsonian syndrome, which can be typical or atypical, and are present only in a particular geographically defined location or population. Ten phenotypes of endemic parkinsonism are currently known: three in the Western Pacific region; two in the Asian-Oceanic region; one in the Caribbean islands of Guadeloupe and Martinique; and four in Europe. Some of these disease entities seem to be disappearing over time and therefore are probably triggered by unique environmental factors. By contrast, other types persist because they are exclusively genetically determined. Given the geographical clustering and potential overlap in biological and clinical features of these exceptionally interesting diseases, this Review provides a historical reference text and offers current perspectives on each of the 10 phenotypes of endemic parkinsonism. Knowledge obtained from the study of these disease entities supports the hypothesis that both genetic and environmental factors contribute to the development of neurodegenerative diseases, not only in endemic parkinsonism but also in general. At the same time, this understanding suggests useful directions for further research in this area.

VPS35 mutation in Japanese patients with typical Parkinson's disease.

Vacuolar protein sorting 35 (VPS35) was recently reported to be a pathogenic gene for late-onset autosomal dominant Parkinson's disease (PD), using exome sequencing. To date, VPS35 mutations have been detected only in whites with PD. The aim of the present study was to determine the incidence and clinical features of Asian PD patients with VPS35 mutations. We screened 7 reported nonsynonymous missense variants of VPS35, including p.D620N, known as potentially disease-associated variants of PD, in 300 Japanese index patients with autosomal dominant PD and 433 patients with sporadic PD (SPD) by direct sequencing or high-resolution melting (HRM) analysis. In addition, we screened 579 controls for the p.D620N mutation by HRM analysis. The p.D620N mutation was detected in 3 patients with autosomal dominant PD (1.0%), in 1 patient with SPD (0.23%), and in no controls. None of the other reported variants of VPS35 were detected. Haplotype analysis suggested at least 3 independent founders for Japanese patients with p.D620N mutation. Patients with the VPS35 mutation showed typical tremor-predominant PD. We report Asian PD patients with the VPS35 mutation. Although VPS35 mutations are uncommon in PD, the frequency of such mutation is relatively higher in Japanese than reported in other populations. In VPS35, p.D620N substitution may be a mutational hot spot across different ethnic populations. Based on the clinical features, VPS35 should be analyzed in patients with PD, especially autosomal dominant PD or tremor-predominant PD.

APOE Alleles With Tau and Aß Pathology in Patients With Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex in the Kii Peninsula.

BACKGROUND AND OBJECTIVES: To examine the association of the APOE ε4 and ε2 alleles with the pathologic features of patients with amyotrophic lateral sclerosis and parkinsonism-dementia complex cases in the Kii peninsula of Japan (Kii ALS/PDC). METHODS: We analyzed APOE variants in 18 autopsy patients with ALS/PDC, consisting of 9, 8, and 1 patient with PDC, ALS, and PDC followed by ALS, respectively. Moreover, we revealed the relationship between APOE variants and Aß and tau pathologies. RESULTS: The frequency of the ε4 allele was not different between patients with Kii ALS/PDC and control participants. APOE ε4 was associated with increased Aß pathology (p = 0.005 by the χ 2 test), but not with increased tau pathology (p = 0.984). The frequency of the ε2 allele was apparently higher than that of control participants (p = 0.254). The APOE ε2 allele was associated with increased tau pathology (p = 0.009) and not with reduced Aß pathology (p = 0.383) in patients with Kii ALS/PDC. DISCUSSION: Although there was no overrepresentation of the frequency of the ε4 or ε2 allele, our findings suggest that the ε2 allele is associated with increased tau pathology and not with reduced Aß pathology in patients with Kii ALS/PDC.

PLA2G6 variant in Parkinson's disease.

PLA2G6 was reported recently as the causative gene for PARK14-linked autosomal recessive early-onset dystonia-parkinsonism. In a recent study in Singapore, heterozygous PLA2G6 p.P806R (c.2417C>G) mutation in exon 17 was reported to be a possible Parkinson's disease (PD)-related mutation. To determine the significance of the PLA2G6 mutation, we conducted an association study by performing direct sequencing of PLA2G6 exon 17 in 379 Japanese sporadic PD patients and 310 controls in the Japanese general population. In this group, we found 12 patients (12/379=3.16%) and 10 controls (10/310=3.23%) with a heterozygous p.P806R mutation (P=0.96, χ(2)=0.0019). Therefore, our large case-controlled study suggests that PLA2G6 p.P806R is not a disease-associated polymorphism in PD. Moreover, we performed direct sequencing of all exons and exon-intron boundaries of PLA2G6 in 116 Japanese patients with sporadic PD. Two single heterozygous variants (p.R301C or p.D331N) were found (both frequencies: 1/379 patients vs 0/310 controls) and the roles of their variants were unclear. Finally, combined with the previous report, our findings emphasize that PLA2G6 mutations are unlikely to be the major causes or risk factors of PD at least in Asian populations. However, further large studies in various populations are needed because patients with PLA2G6 mutations can show heterogeneous clinical features.

[A case of status epilepticus with a possible therapeutic effect by dantrolene sodium].

We report a 62-year-old man who have taken major tranquilizer for schizophrenia for the past 24 years. He had sudden generalized tonic-clonic seizure and consciousness loss on April 2010. He was administered diazepam, phenytoin, phenobarbital intravenously and drip-infused with midazolam continuously, but the seizure persisted. For a possible comorbidity of neuroleptic malignant syndrome, we administered dantrolene sodium intravenously and bromocriptine through a nasal gastric tube. The refractory status epilepticus disappeared immediately after the administration. Status epilepticus remitted 2 days later but again disappeared with repeated injection of dantrolene. These results suggested that intravenous administration of dantrolene may have alleviated the refractory symptoms of status epilepticus.

Initial Result of Stroke Care at the Stroke Center in a New Hospital Opened by the Merger of Three Facilities with Different Management Bases: Effect of Stroke Center on Mechanical Thrombectomy.

Objective: The most important function required for the stroke center is prompt treatment for acute stroke. We report the initial results of stroke care under the new medical care system of stroke center in a new hospital that merges three hospitals with different management bases to verify the effect of stroke center on mechanical thrombectomy. Methods: We investigated changes in the number of inpatients and surgical treatments compared with the past 3 years (Stages I, II, and III) with stage IV one year after the new hospital was opened, and examined the effect of establishing a stroke center on mechanical thrombectomy for acute main cerebral artery occlusion. Results: From stage I to stage IV, the number of hospitalized patients increased from 396, 485, 482 to 630, respectively, and the proportion of patients with cerebrovascular disease increased from 57.6%, 55.7%, 60.4% to 68.3%, respectively. Total surgical treatment increased from 137, 195, 224 to 297, respectively, especially endovascular therapy increased markedly from 22, 36, 68 to 118, respectively. The main treatment contents of endovascular treatment in stage IV were ruptured cerebral aneurysm embolization 22 cases, unruptured cerebral aneurysm embolization 13 cases, carotid artery stenting 23 cases, other intracranial or extracranial artery angioplasty/stenting 9 cases, and mechanical thrombectomy 34 cases. In particular, mechanical thrombectomy was significantly increased to 34 in stage IV, compared to 4 in stage I, 4 in stage II, and 17 in stage III (degree of contribution [DC] 25.0%, contribution ratio [CR] 34.0%). Conclusion: With the establishment of the stroke center, the number of cases of acute cerebral infarction within the adaptation time who received mechanical thrombectomy remarkably increased. It is considered that the effect and validity of function aggregation by establishing stroke center are shown.

TRPM7 is not associated with amyotrophic lateral sclerosis-parkinsonism dementia complex in the Kii peninsula of Japan.

Amyotrophic lateral sclerosis-parkinsonism dementia complex (ALS/PDC) is a distinct neurodegenerative disorder characterized by ALS pathology with neurofibrillary tangles (NFTs) in the spinal cord and brain. Recent clinical studies have revealed a high incidence and a high familial occurrence of ALS/PDC in both Guam and the Kii peninsula of Japan, suggesting a strong genetic predisposition to this disorder. The T1482I variant (rs8042919) of TRPM7 gene which is suggested to play roles in regulating the cellular homeostasis of Ca(2+), Mg(2+), and trace metals, has recently been reported to be associated with Guamanian patients with ALS/PDC. To investigate whether TRPM7 is associated with Kii ALS/PDC, we conducted parametric linkage analyses of the TRPM7 locus in a large extended family with ALS/PDC. Linkage analysis did not reveal any evidence supporting the linkage to the TRPM7 locus. Resequencing of the entire coding region of TRPM7 did not reveal any pathogenic mutations in an affected individual in this family. The allele frequencies of the T1482I in affected individuals in this family or in those from other families are not significantly different from those in regional controls or those in HapMap-JPT samples. These results indicate that TRPM7 is not associated with ALS/PDC in the Kii peninsula of Japan.

Mutation spectrum and health status in skeletal muscle channelopathies in Japan.

Skeletal muscle channelopathies, including non-dystrophic myotonia and periodic paralysis, are rare hereditary disorders caused by mutations of various ion channel genes. To define the frequency of associated mutations of skeletal muscle channelopathies in Japan, clinical and genetic data of two academic institutions, which provides genetic analysis service, were reviewed. Of 105 unrelated pedigrees genetically confirmed, 66 pedigrees were non-dystrophic myotonias [CLCN1 (n = 30) and SCN4A (n = 36)], 11 were hyperkalemic periodic paralysis (SCN4A), and 28 were hypokalemic periodic paralysis [CACNA1S (n = 16) and SCN4A (n = 12)]. Of the 30 families with myotonia congenita, dominant form (Thomsen type) consisted 67%, and unique mutations, A298T, P480T, T539A, and M560T, not found in Western countries, were commonly identified in CLCN1. Hypokalemic periodic paralysis caused by SCN4A mutations consisted 43% in Japan, which was much higher than previous reports. Furthermore, the quality of life of the patients was assessed using the patient-reported outcome measures, SF-36 and INQoL, for 41 patients. This study indicated that the etiology of skeletal muscle channelopathies in Japan was not identical to previous reports from Western countries, and provided crucial information for genetics as well as future therapeutic interventions.

Analysis of the genetic background associated with sporadic periodic paralysis in Japanese patients.

Periodic paralysis (PP) is a rare disease caused by abnormal excitability of the sarcolemma, resulting in the episodic weakness in extremities. Two major subtypes have been identified: primary/familial PP showing Mendelian inheritance of a mutation in the ion channel genes expressed in skeletal muscle, and secondary/sporadic PP which does not show Mendelian inheritance. Thyrotoxic periodic paralysis (TPP) contributes to the majority of secondary PP cases in Asians and Latin Americans, suggesting that genetic factors may underlie the pathogenesis. In contrast, sporadic periodic paralysis (SPP) has no familial history and no secondary factors. The genetic features associated with SPP in Japanese patients remain unexplored. Here, we investigate whether nine single nucleotide variants (SNVs), rs623011, rs312691, rs393743, rs312692, rs312736, rs992072, rs312732, rs723498, and rs312707, found in TPP and/or SPP in other Asian populations are also associated with Japanese SPP cases. The study cohort included 43 Japanese periodic paralysis patients with no mutations in causative genes (SCN4A, CACNA1S, and KCNJ2), no myotonia, and with euthyroid function. The results showed disease susceptibility for all nine SNVs in our Japanese SPP cohort. One of them, rs312691, was newly confirmed to show susceptibility to SPP. Our results suggest the genetic background underlies periodic paralysis.

Expression of Mutant Ubiquitin and Proteostasis Impairment in Kii Amyotrophic Lateral Sclerosis/Parkinsonism-Dementia Complex Brains.

Kii amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) is a progressive neurodegenerative disorder that is endemic to the Kii peninsula of Japan. The disorder is clinically characterized by a variable combination of parkinsonism, dementia, and motor neuron symptoms. Despite extensive investigations, the etiology and pathogenesis of ALS/PDC remain unclear. At the neuropathological level, Kii ALS/PDC is characterized by neuronal loss and tau-dominant polyproteinopathy. Here, we report the accumulation of several proteins involved in protein homeostasis pathways, that is, the ubiquitin-proteasome system and the autophagy-lysosome pathway, in postmortem brain tissue from a number of Kii ALS/PDC cases (n = 4). Of particular interest is the presence of a mutant ubiquitin protein (UBB+1), which is indicative of disrupted ubiquitin homeostasis. The findings suggest that abnormal protein aggregation is linked to impaired protein homeostasis pathways in Kii ALS/PDC.

Paramyotonia Congenita with Persistent Distal and Facial Muscle Weakness: A Case Report with Literature Review.

BACKGROUND: Paramyotonia congenita (PC; OMIM 168300) is a non-dystrophic myotonia caused by mutations in the SCN4A gene. Transient muscle stiffness, usually induced by exposure to cold and aggravated by exercise, is the predominant clinical symptom, and interictal persistent weakness is uncommon. CASE REPORT: We report a family with a history of PC accompanied by persistent hand muscle weakness with masticatory muscle involvement. Persistent weakness was exacerbated with age, and MR analysis showed marked atrophy of temporal, masseter, and finger flexor muscles with fatty replacement. The PC causative mutation T1313M in the SCN4A gene was prevalent in the family. Administration of acetazolamide chloride improved clinical symptoms and the results of cold and short exercise tests. Phenotypic variation within the family was remarkable, as the two younger affected patients did not present with persistent weakness or muscle atrophy. CONCLUSIONS: PC associated with the T1313M mutation is a possible cause of persistent distal hand weakness.

Mouse model of multiple system atrophy alpha-synuclein expression in oligodendrocytes causes glial and neuronal degeneration.

Transgenic (Tg) mice overexpressing human wild-type alpha-synuclein in oligodendrocytes under the control of the 2,' 3'-cyclic nucleotide 3'-phosphodiesterase (CNP) promoter are shown here to recapitulate features of multiple system atrophy (MSA), including the accumulation of filamentous human alpha-synuclein aggregates in oligodendrocytes linked to their degeneration and autophagocytosis of myelin. Significantly, endogenous mouse alpha-synuclein also accumulated in normal and degenerating axons and axon terminals in association with oligodendroglia and neuron loss and slowly progressive motor impairments. Our studies demonstrate that overexpression of alpha-synuclein in oligodendrocytes of mice results in MSA-like degeneration in the CNS and that alpha-synuclein inclusions in oligodendrocytes participate in the degeneration of neurons in MSA.

Chronic cerebral hypoperfusion upregulates leptin receptor expression in astrocytes and tau phosphorylation in tau transgenic mice.

Alzheimer's disease (AD) is the most common type of dementia in aging adults. Increasing evidence has revealed that vascular risk factors influence the midlife development of AD and that diet-induced obesity accelerates tau phosphorylation in tau transgenic mice and increases the level of serum leptin receptor (leptin-R). Leptin-R is upregulated in the peri-infarct cortices after acute cerebral ischemia. Leptin may be protective against the development of AD as it can inactivate GSK-3ß through the phosphorylation of Ser-9, leading to the reduction of tau phosphorylation. Using tau transgenic mice, the present study examined whether chronic cerebral hypoperfusion affects leptin-R signaling and tau phosphorylation. Eight-month-old tau transgenic mice (T44) overexpressing the shortest human tau isoform were subjected to chronic cerebral hypoperfusion with bilateral common carotid artery stenosis (BCAS) using microcoils or sham surgery. Their brains were analyzed four weeks later to evaluate the expression of phosphorylated tau and leptin-R via immunohistochemistry and Western blot analysis. In addition, expression of leptin-R was examined in the rat primary astrocyte cultures subjected to prolonged chemical hypoxic stress, as well as in autopsied brains. BCAS upregulated leptin-R expression and promoted the expression of phosphorylated tau in T44 Tg mice. In primary astrocyte cultures, leptin-R was upregulated under hypoxic conditions via the phosphorylated AKT/pAKT pathway, possibly suppressing the expression of caspase 3. Leptin-R was also strongly expressed in autopsied brains with AD and cerebrovascular diseases. These results collectively indicate that chronic cerebral hypoperfusion promotes leptin-R signaling and tau phosphorylation.

Functional analysis of a double-point mutation in the KCNJ2 gene identified in a family with Andersen-Tawil syndrome.

Andersen-Tawil syndrome (ATS) is a skeletal muscle channelopathy with autosomal dominant inheritance resulting in periodic paralysis, arrhythmia characterized by QT prolongation, and dysmorphic features. The KCNJ2 gene has been identified as the causative gene of ATS. Herein, we reported 2 cases of a 21-year-old man and his mother, with episodic paralytic attacks and/or arrhythmia, which are characteristic of ATS. Both G144A, a reported ATS mutation, and V296F, a novel mutation, were identified in the KCNJ2 gene on the same allele from the proband and his mother, but not from his father. In the present study, we investigated the functional effect of these variants on the potassium channel Kir2.1 and the significance of the double mutation. G144A, V296F, and G144A-V296F mutant channels expressed in cultured cells revealed a loss-of-function effect of these mutations on Kir2.1. The K+ currents of G144A and G144A-V296F channels were more suppressed than that of V296F channel alone, whereas was no difference between G144A and G144A-V296F. To our knowledge, a double mutation in the KCNJ2 gene has not been reported previously. While either of 2 mutations potentially causes ATS, the G144A mutation might cause the dominant effect on the patients' clinical presentation.