Imaharu Nakano

Phosphorylated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis.

TAR DNA‐binding protein of 43kDa (TDP‐43) is deposited as cytoplasmic and intranuclear inclusions in brains of patients with frontotemporal lobar degeneration with ubiquitinated inclusions (FTLD‐U) and amyotrophic lateral sclerosis (ALS). Previous studies reported that abnormal phosphorylation takes place in deposited TDP‐43. The aim of this study was to identify the phosphorylation sites and responsible kinases, and to clarify the pathological significance of phosphorylation of TDP‐43.

A Phase I Study of Aromatic l-Amino Acid Decarboxylase Gene Therapy for Parkinson's Disease

Gene transfer of dopamine-synthesizing enzymes into the striatal neurons has led to behavioral recovery in animal models of Parkinsons disease (PD). We evaluated the safety, tolerability, and potential efficacy of adeno-associated virus (AAV) vector-mediated gene delivery of aromatic L-amino acid decarboxylase (AADC) into the putamen of PD patients. Six PD patients were evaluated at baseline and at 6 months, using multiple measures, including the Unified Parkinsons Disease Rating Scale (UPDRS), motor state diaries, and positron emission tomography (PET) with 6-[(18)F]fluoro-L-m-tyrosine (FMT), a tracer for AADC. The short-duration response to levodopa was measured in three patients. The procedure was well tolerated. Six months after surgery, motor functions in the OFF-medication state improved an average of 46% based on the UPDRS scores, without apparent changes in the short-duration response to levodopa. PET revealed a 56% increase in FMT activity, which persisted up to 96 weeks. Our findings provide class IV evidence regarding the safety and efficacy of AADC gene therapy and warrant further evaluation in a randomized, controlled, phase 2 setting.Gene transfer of dopamine-synthesizing enzymes into the striatal neurons has led to behavioral recovery in animal models of Parkinsons disease (PD). We evaluated the safety, tolerability, and potential efficacy of adeno-associated virus (AAV) vector-mediated gene delivery of aromatic L-amino acid decarboxylase (AADC) into the putamen of PD patients. Six PD patients were evaluated at baseline and at 6 months, using multiple measures, including the Unified Parkinsons Disease Rating Scale (UPDRS), motor state diaries, and positron emission tomography (PET) with 6-[18F]fluoro-L-m-tyrosine (FMT), a tracer for AADC. The short-duration response to levodopa was measured in three patients. The procedure was well tolerated. Six months after surgery, motor functions in the OFF-medication state improved an average of 46% based on the UPDRS scores, without apparent changes in the short-duration response to levodopa. PET revealed a 56% increase in FMT activity, which persisted up to 96 weeks. Our findings provide class IV evidence regarding the safety and efficacy of AADC gene therapy and warrant further evaluation in a randomized, controlled, phase 2 setting.

Delayed delivery of AAV-GDNF prevents nigral neurodegeneration and promotes functional recovery in a rat model of Parkinson's disease

Glial cell line-derived neurotrophic factor (GDNF) is a strong candidate agent in the neuroprotective treatment of Parkinsons disease (PD). We investigated whether adeno-associated viral (AAV) vector-mediated delivery of a GDNF gene in a delayed manner could prevent progressive degeneration of dopaminergic (DA) neurons, while preserving a functional nigrostriatal pathway. Four weeks after a unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA), rats received injection of AAV vectors expressing GDNF tagged with FLAG peptide (AAV-GDNFflag) or β-galactosidase (AAV-LacZ) into the lesioned striatum. Immunostaining for FLAG demonstrated retrograde transport of GDNFflag to the substantia nigra (SN). The density of tyrosine hydroxylase (TH)-positive DA fibers in the striatum and the number of TH-positive or cholera toxin subunit B (CTB, neuronal tracer)-labeled neurons in the SN were significantly greater in the AAV-GDNFflag group than in the AAV-LacZ group. Dopamine levels and those of its metabolites in the striatum were remarkably higher in the AAV-GDNFflag group compared with the control group. Consistent with anatomical and biochemical changes, significant behavioral recovery was observed from 4–20 weeks following AAV-GDNFflag injection. These data indicate that a delayed delivery of GDNF gene using AAV vector is efficacious even 4 weeks after the onset of progressive degeneration in a rat model of PD.

A revision of the El Escorial criteria - 2015

There has been much discussion as to the necessity for adjustment of the El Escorial diagnostic criteria, primarily based on observations relating to the specificity of the‘Possible’ category. The ...

Age at onset influences on wide-ranged clinical features of sporadic amyotrophic lateral sclerosis

PURPOSE To profile the detailed clinical features of sporadic amyotrophic lateral sclerosis (ALS) on large-scale samples in Japan. METHODS We assessed the clinical features of sporadic ALS patients in Japan, based on the nationwide registration system of the Ministry of Health, Labor and Welfare of Japan. We described 3,428 new cases registered cases between 2003 and 2006 to analyze initial symptoms and related clinical features, 4,202 cases registered in the single year of 2005 to describe the cross-sectional overview of the ALS patients, and a total of 2,128 cases with tracheostomy positive pressure ventilation (TPPV) from all of the registration data from 2003 to 2006 to describe the features of ALS patients with TPPV. RESULTS The patients with an older age at onset progressed more rapidly to the TPPV stage than those with a younger age at onset. The subpopulation of patients with long-standing TPPV showed ophthalmoplegia, while its appearance rate was less in the patients with an older age at onset than in those with a younger age at onset. Furthermore, age at onset strongly influenced the frequency of initial symptoms: dysarthria, dysphagia, neck weakness and respiratory disturbance were more frequent in patients with an older age at onset, while upper or lower limb weakness was observed more frequently in patients with a younger age at onset. In addition, those initial symptoms were still the most prominent at the follow-up stage, suggesting that the initial symptoms determine the major clinical features even in advanced illness. CONCLUSIONS Our present study demonstrated that symptomatic features of ALS are strongly influenced by the age at onset by the large scale of samples.

Cerebral small-vessel disease protein HTRA1 controls the amount of TGF-β1 via cleavage of proTGF-β1

Cerebral small-vessel disease is a common disorder in elderly populations; however, its molecular basis is not well understood. We recently demonstrated that mutations in the high-temperature requirement A (HTRA) serine peptidase 1 (HTRA1) gene cause a hereditary cerebral small-vessel disease, cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). HTRA1 belongs to the HTRA protein family, whose members have dual activities as chaperones and serine proteases and also repress transforming growth factor-β (TGF-β) family signaling. We demonstrated that CARASIL-associated mutant HTRA1s decrease protease activity and fail to decrease TGF-β family signaling. However, the precise molecular mechanism for decreasing the signaling remains unknown. Here we show that increased expression of ED-A fibronectin is limited to cerebral small arteries and is not observed in coronary, renal arterial or aortic walls in patients with CARASIL. Using a cell-mixing assay, we found that HTRA1 decreases TGF-β1 signaling triggered by proTGF-β1 in the intracellular space. HTRA1 binds and cleaves the pro-domain of proTGF-β1 in the endoplasmic reticulum (ER), and cleaved proTGF-β1 is degraded by ER-associated degradation. Consequently, the amount of mature TGF-β1 is reduced. These results establish a novel mechanism for regulating the amount of TGF-β1, specifically, the intracellular cleavage of proTGF-β1 in the ER.

Intramuscular injection of AAV-GDNF results in sustained expression of transgenic GDNF, and its delivery to spinal motoneurons by retrograde transport

Adeno-associated virus (AAV) vector has been developed as an attractive gene delivery system with proven safety. Glial cell line-derived neurotrophic factor (GDNF) is proposed to be a promising therapeutic agent for amyotrophic lateral sclerosis (ALS) and other motor neuron diseases. The purpose of this report was to investigate transgenic GDNF expression at different time points post AAV mediated GDNF intramuscular delivery. An AAV vector was constructed to encode a recombinant fusion of GDNF tagged with a FLAG sequence at the C-terminal (AAV-GDNF) to distinguish it from its endogenous counterpart. A single intramuscular injection of AAV-GDNF led to substantial expression of transgenic GDNF which remained for at least 10 months in transduced gastrocnemius muscle. This transgenic GDNF was distributed in a large number of myofibers, mainly in the vicinity of the sarcolemma and predominantly concentrated at the sites of neuromuscular junctions (NMJs). Furthermore, transgenic GDNF, but not beta-galactosidase expressed as a control, was detected in the motoneurons that projected axons to the injected muscles, thus, indicating retrograde axonal transportation of the transgenic GDNF. This study provides a basis for a strategy of intramuscular AAV-GDNF delivery to protect motoneurons as a possible means of ALS treatment.

A homozygous mutation of C12orf65 causes spastic paraplegia with optic atrophy and neuropathy (SPG55).

Background Autosomal recessive hereditary spastic paraplegias (AR-HSP) constitute a heterogeneous group of neurodegenerative diseases involving pyramidal tracts dysfunction. The genes responsible for many types of AR-HSPs remain unknown. We attempted to identify the gene responsible for AR-HSP with optic atrophy and neuropathy. Methods The present study involved two patients in a consanguineous Japanese family. Neurologic examination and DNA analysis were performed for both patients, and a skin biopsy for one. We performed genome-wide linkage analysis involving single nucleotide polymorphism arrays, copy-number variation analysis, and exome sequencing. To clarify the mitochondrial functional alteration resulting from the identified mutation, we performed immunoblot analysis, mitochondrial protein synthesis assaying, blue native polyacrylamide gel electrophoresis (BN-PAGE) analysis, and respiratory enzyme activity assaying of cultured fibroblasts of the patient and a control. Results We identified a homozygous nonsense mutation (c.394C>T, p.R132X) in C12orf65 in the two patients in this family. This C12orf65 mutation was not found in 74 Japanese AR-HSP index patients without any mutations in previously known HSP genes. This mutation resulted in marked reduction of mitochondrial protein synthesis, followed by functional and structural defects in respiratory complexes I and IV. Conclusions This novel nonsense mutation in C12orf65 could cause AR-HSP with optic atrophy and neuropathy, resulting in a premature stop codon. The truncated C12orf65 protein must lead to a defect in mitochondrial protein synthesis and a reduction in the respiratory complex enzyme activity. Thus, dysfunction of mitochondrial translation could be one of the pathogenic mechanisms underlying HSPs.

The El Escorial criteria: Strengths and weaknesses

Abstract The El Escorial criteria for the diagnosis of amyotrophic lateral sclerosis (ALS) were established 20 years ago and have been used as inclusion criteria for clinical trials. However, concerns have been raised concerning their use as diagnostic criteria in clinical practice. Moreover, as modern genetics have shed new light on the heterogeneity of ALS and the close relationship between ALS and frontotemporal dementia (FTD) recognized, the World Federation of Neurology Research Group on ALS/MND has initiated discussions to amend and update the criteria, while preserving the essential components for clinical trial enrolment purposes.

Multitracer assessment of dopamine function after transplantation of embryonic stem cell-derived neural stem cells in a primate model of Parkinson's disease

The ability of primate embryonic stem (ES) cells to differentiate into dopamine (DA)‐synthesizing neurons has raised hopes of creating novel cell therapies for Parkinsons disease (PD). As the primary purpose of cell transplantation in PD is restoration of dopaminergic neurotransmission in the striatum, in vivo assessment of DA function after grafting is necessary to achieve better therapeutic effects. A chronic model of PD was produced in two cynomolgus monkeys (M‐1 and M‐2) by systemic administration of neurotoxin. Neural stem cells (NSCs) derived from cynomolgus ES cells were implanted unilaterally in the putamen. To evaluate DA‐specific functions, we used multiple [11C]‐labeled positron emission tomography (PET) tracers, including [β‐11C]L‐3,4‐dihydroxyphenylalanine (L‐[β‐11C]DOPA, DA precursor ligand), [11C]‐2β‐carbomethoxy‐3β‐(4‐fluorophenyl)tropane ([11C]β‐CFT, DA transporter ligand) and [11C]raclopride (D2 receptor ligand). At 12 weeks after grafting NSCs, PET demonstrated significantly increased uptake of L‐[β‐11C]DOPA (M‐1:41%, M‐2:61%) and [11C]β‐CFT (M‐1:31%, M‐2:36%) uptake in the grafted putamen. In addition, methamphetamine challenge in M‐2 induced reduced [11C]raclopride binding (16%) in the transplanted putamen, suggesting release of DA. These results show that transplantation of NSCs derived from cynomolgus monkey ES cells can restore DA function in the putamen of a primate model of PD. PET with multitracers is useful for functional studies in developing cell‐based therapies against PD. Synapse 63: 541‐548, 2009.