RGMa collapses the neuronal actin barrier against disease-implicated protein and exacerbates ALS.

Repulsive guidance molecule A (RGMa) was originally identified as a neuronal growth cone-collapsing factor. Previous reports have demonstrated the multifunctional roles of RGMa mediated by neogenin1. However, the pathogenic involvement of RGMa in amyotrophic lateral sclerosis (ALS) remains unclear. Here, we demonstrated that RGMa concentration was elevated in the cerebrospinal fluid of both patients with ALS and transgenic mice overexpressing the mutant human superoxide dismutase1 (mSOD1 mice). Treatment with humanized anti-RGMa monoclonal antibody ameliorated the clinical symptoms in mSOD1 mice. Histochemical analysis revealed that the anti-RGMa antibody significantly decreased mutant SOD1 protein accumulation in the motor neurons of mSOD1 mice via inhibition of actin depolymerization. In vitro analysis revealed that the anti-RGMa antibody inhibited the cellular uptake of the mutant SOD1 protein, presumably by reinforcing the neuronal actin barrier. Collectively, these data suggest that RGMa leads to the collapse of the neuronal actin barrier and promotes aberrant protein deposition, resulting in exacerbation of the ALS pathology.

An MFN2-related Charcot-Marie-Tooth Disease Patient with Optic Nerve Atrophy, Neurogenic Bladder Dysfunction, and Diaphragmatic Weakness.

Charcot-Marie-Tooth disease (CMT) is a common hereditary peripheral polyneuropathy encompassing distinct monogenetic disorders. Pathogenic mutations in mitofusin 2 (MFN2) are the most frequent cause of its axonal type, CMT type 2A, with diverse phenotypes. We herein report a Japanese patient with a novel heterozygous MFN2 pathogenic variant (c.740 G>C, p.R247P) and severe CMT phenotypes, including progressive muscle weakness, optic atrophy, urinary inconsistency, and restrictive pulmonary dysfunction with eventration of the diaphragm that developed over her 60-year disease course. Our case expands the clinico-genetic features of MFN2-related CMT and highlights the need to evaluate infrequent manifestations during long-term care of CMT patients.

Mitochondrial DNA enhance innate immune responses in neuromyelitis optica by monocyte recruitment and activation.

Although recent studies indicate the involvement of monocytes in accelerating the lesion formation of neuromyelitis optica spectrum disorder (NMOSD), the precise mechanism of the innate immune system activation remains elusive. Thus, in this study, we aimed to clarify the mechanisms of NMOSD pathogenesis from the viewpoint of innate immunity activation. We established anti-AQP4 recombinant autoantibodies (Ab) from plasmablasts in NMOSD patient's CSF. Human astrocytes treated with anti-AQP4 Ab produced a significant amount of CCL2 and contributed to the efficient recruitment of monocytes. Moreover, mitochondrial DNA (mtDNA), which activated monocytes via Toll-like receptor 9 (TLR9), was released from astrocytes treated with anti-AQP4 Ab. MtDNA further enhanced CCL2 production by monocytes, and it was demonstrated that mtDNA concentration correlated with the efficiency of monocyte recruitment in the CSF of NMOSD patients. In conclusion, these observations highlight that mtDNA which was released from astrocytes damaged by anti-AQP4 Ab has a central role in establishing the inflammatory loop of monocyte recruitment and activation via an innate immunity pathway.

Synchrotron FTIR micro-spectroscopy for structural analysis of Lewy bodies in the brain of Parkinson's disease patients.

Lewy bodies (LBs), which mainly consist of α-synuclein (α-syn), are neuropathological hallmarks of patients with Parkinson's disease (PD). The fine structure of LBs is unknown, and LBs cannot be made artificially. Nevertheless, many studies have described fibrillisation using recombinant α-syn purified from E. coli. An extremely fundamental problem is whether the structure of LBs is the same as that of recombinant amyloid fibrils. Thus, we used synchrotron Fourier transform infrared micro-spectroscopy (FTIRM) to analyse the fine structure of LBs in the brain of PD patients. Our results showed a shift in the infrared spectrum that indicates abundance of a ß-sheet-rich structure in LBs. Also, 2D infrared mapping of LBs revealed that the content of the ß-sheet structure is higher in the halo than in the core, and the core contains a large amount of proteins and lipids.

[A case of dysferlinopathy asymptomatic for 10 years after an episode of transient muscle weakness].

We report a 28-year-old male with dysferlinopathy, who has remained asymptomatic for 10 years from a rhabdomyolysis-like episode. He had been in good health since birth, but felt difficulty in walking after a month and a half of manual labor at 18 years old (at the year 2000). Rhabdomyolysis was suspected because of muscle weakness and elevated serum CK of 28,094U/L. He was hospitalized and his muscle weakness improved. He was referred to us, because his serum CK remained around 2,000U/L. Histological analysis of muscle, when anti-dysferlin antibody was unavailable, was not informative but later analysis at the age of 23 using preserved specimen showed loss of dysferlin immunoreactivity. Subsequently, a missense mutation (c.2997G>T) and a deletion (c.3373delG) of the dysferlin gene, both of which are common in Miyoshi myopathy in Japanese, were identified. He continuously showed hyper-CKemia, but no apparent muscle weakness emerged for more than ten years. Reports on asymptomatic dysferlinopathy over such a long duration are rare. This case may suggest that genetic factors, environmental factors such as intensity of work-load, or both, might affect the clinical course of dysferlinopathy. Further follow-up is necessary.

Adult-onset multiple acyl CoA dehydrogenation deficiency associated with an abnormal isoenzyme pattern of serum lactate dehydrogenase.

We report a case of a 37 year-old male with multiple acyl-CoA dehydrogenation deficiency (MADD). The patient had suffered from exercise intolerance in his hip and thigh muscles for one year. Then, restriction of carbohydrates for a diet made his symptoms rapidly deteriorate. Blood test revealed compound heterozygosity for two novel missense mutations in the electron transfer flavoprotein dehydrogenase gene (ETFDH), and an abnormal LDH isoenzyme pattern: LDH-1 (60.0%) and LDH-2 (26.0%) predominated with abnormally elevated LDH-1/LDH-2 ratio (2.3), compared with muscle-derived LDH-5 (4.0%). Oral riboflavin treatment significantly improved his exercise intolerance and the LDH profile: LDH-1 (34.4%), LDH-2 (34.9%), LDH-5 (6.9%) and LDH-1/LDH-2 ratio (1.0). The abnormal LDH isoenzyme pattern may be one feature of adult-onset MADD selectively affecting type I muscle fibers with relatively high LDH-1 content.

Nuclear TAR DNA binding protein 43 expression in spinal cord neurons correlates with the clinical course in amyotrophic lateral sclerosis.

TAR DNA binding protein 43 (TDP-43) has been considered a signature protein in frontotemporal dementia and amyotrophic lateral sclerosis (ALS), but not in ALS associated with the superoxide dismutase 1 (SOD1) gene mutations (ALS1). To clarify how TDP may be involved in ALS pathogenesis, clinical and pathological features in cases of sporadic ALS ([SALS] n = 18) and ALS1 (n = 6) were analyzed. In SALS patients with rapid clinical courses, TDP mislocalization (i.e. cytoplasmic staining and TDP-positive cytoplasmic inclusions) in anterior horn cells was frequent. In SALS patients with slow clinical courses, TDP-43 mislocalization was rare. In an ALS1 patient with the SOD1 gene mutation C111Y, there were numerous TDP-positive inclusions and colocalization of SOD1 and TDP. In mutant SOD1 transgenic (G93A) mice at the end stage (median, 256 days), TDP-positive inclusions and TDP colocalization with SOD1 were also observed; nuclear TDP-43 immunoreactivity was highly correlated with life span in these mice. In both humans and mice, nuclei that stained strongly for TDP were large and circular; weakly stained nuclei were atrophic or deformed. In conclusion, low levels of TDP expression in the nucleus cor relate with a rapid clinical course in SALS and in ALS1 model mice, suggesting that nuclear TDP may play a protective role against motor neuron death resulting from different underlying etiologies.

Pioglitazone promotes peripheral nerve remyelination after crush injury through CD36 upregulation.

In our previous study, we found that CD36-deficient mice showed significant delays in peripheral nerve remyelination after sciatic nerve crush injury and suggested that CD36 played an important role in the restoration of injured peripheral nerves. The aim of this study was to investigate whether CD36 upregulation can promote peripheral nerve remyelination. We made crush injury that caused demyelination and mild axonal degeneration to sciatic nerves and investigated the effect of pioglitazone (PIO) on the remyelination post-injury in C57Bl/6 wild-type and CD36-deficient mice. The immunohistochemistry with anti-CD36 antibody showed that CD36 was upregulated in macrophages infiltrating peripheral nerves from the wild-type mice by PIO administration at 1 week post-injury. The lectin histochemistry represented that infiltrating macrophages lessened in the wild-type mice at 3 weeks post-injury by PIO administration. General histopathology and morphometry indicated that thinly myelinated fibers and naked axons diminished in PIO-treated wild-type mice compared with non-treated wild-type mice at 3 weeks post-injury. No significant differences were observed in remyelination and number of infiltrating macrophages between PIO-treated and non-treated CD36-deficient mice. These results indicate that PIO promotes peripheral nerve remyelination possibly through CD36. It may be possible to apply PIO to the remedy against demyelinating neuropathies.

Neuroaxonal dystrophy caused by group VIA phospholipase A2 deficiency in mice: a model of human neurodegenerative disease.

Calcium-independent group VIA phospholipase A2 (iPLA2beta) is considered to play a role in signal transduction and maintenance of homeostasis or remodeling of membrane phospholipids. A role of iPLA2beta has been suggested in various physiological and pathological processes, including immunity, chemotaxis, and cell death, but the details remain unclear. Accordingly, we investigated mice with targeted disruption of the iPLA2beta gene. iPLA2beta-/- mice developed normally and grew to maturity, but all showed evidence of severe motor dysfunction, including a hindlimb clasping reflex during tail suspension, abnormal gait, and poor performance in the hanging wire grip test. Neuropathological examination of the nervous system revealed widespread degeneration of axons and/or synapses, accompanied by the presence of numerous spheroids (swollen axons) and vacuoles. These findings provide evidence that impairment of iPLA2beta causes neuroaxonal degeneration, and indicate that the iPLA2beta-/- mouse is an appropriate animal model of human neurodegenerative diseases associated with mutations of the iPLA2beta gene, such as infantile neuroaxonal dystrophy and neurodegeneration with brain iron accumulation.

Inverse correlation between the formation of mitochondria-derived vacuoles and Lewy-body-like hyaline inclusions in G93A superoxide-dismutase-transgenic mice.

In G93A mice, the most popular model of amyotrophic lateral sclerosis (ALS), neuronal Lewy-body-like hyaline inclusions (LBHIs) and mitochondria-derived vacuoles are observed in addition to motor neuron loss. Although LBHIs are thought to be toxic, the significance of the mitochondria-derived vacuoles has not been fully investigated. In this study, the relationship between the formation of these vacuoles and LBHIs was clarified statistically in the lumbar segment from two phyletic lines of G93A mice (G1L, G1H), using immunohistochemical methods. Furthermore, the distributions of vacuoles and LBHIs were examined in the pons including the facial nucleus, where pathological changes occur in ALS patients and G93A mice. Numerous vacuoles 2-3 microm in diameter were detected in the neuropil of the lumbar segment from G1L mice euthanatized approximately 3.5 months prior to the onset of the disease. Most of the vacuoles disappeared, but some became larger as the disease progressed. The number of vacuoles with a diameter exceeding 5 microm began to decrease after disease onset, while that of intra-neuritic LBHIs increased rapidly. There was a strong inverse correlation between the numbers of vacuoles and LBHIs in symptomatic mice (P<0.01; G1L, r=-0.91; G1H, r=-0.93). In the facial nucleus of G1L mice, where the number of motor neurons was significantly reduced, only a few LBHIs were detected along with prominent vacuole formation. In contrast, significantly more LBHIs with little vacuole formation were evident around the facial nucleus in G1L mice. Furthermore, the SOD1 immunoreactivity in vacuoles initially increased and then decreased after disease onset. Taken together, the present findings suggest that the mitochondria-derived vacuoles might prevent the formation of LBHIs by sequestering mutated SOD1 from the cytoplasm.

Loss of dopaminergic neurons by the induction of inducible nitric oxide synthase and cyclooxygenase-2 via CD 40: relevance to Parkinson's disease.

A glial reaction associated with up-regulation of inflammatory molecules has been suggested to play an important role in dopaminergic neuron loss in Parkinson's disease (PD). Among inflammatory molecules, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been focused upon as key factors in the pathogenesis. However, the mechanism of how these molecules are induced in PD brains is not clearly understood. We focused on CD 40, which is expressed on neural cells and could be implicated in the neuroinflammation by inducing inflammatory molecules. We showed that both iNOS and COX-2 were up-regulated in microglia and astrocytes by CD 40 stimulation in association with a low dose of interferon-gamma (IFN-gamma) in vitro. Selective loss of dopaminergic neurons was induced by costimulation with CD 40 and IFN-gamma in mesencephalic cultures, which was protected by selective inhibitors of iNOS and/or COX-2. We also found in CD 40-stimulated astrocytes an increase of a low-affinity IgE receptor CD 23, which is known to induce iNOS expression. Together these data suggest that up-regulated iNOS and COX-2 via the CD 40 pathway may lead to dopaminergic neuron loss and may participate in the neuroinflammaory pathway of PD.

Benefit of valproic acid in suppressing disease progression of ALS model mice.

Valproic acid (VPA) has long been used as an antiepileptic drug and recently as a mood stabilizer, and evidence is increasing that VPA exerts neuroprotective effects through changes in a variety of intracellular signalling pathways including upregulation of Bcl-2 protein with an antiapoptotic property and inhibiting glycogen synthase kinase 3-beta, which is considered to promote cell survival. Although the neuroprotective effects of VPA have been demonstrated in a murine model of human immunodeficiency virus-1 encephalitis, there have been no reports on the effect of VPA in chronic progressing neurodegenerative disease models including amyotrophic lateral sclerosis (ALS). ALS is a devastating disease selectively affecting motoneurons, and its disease model mice bear a close resemblance to ALS symptomatically and pathologically. First, we used an organotypic slice culture using mouse spinal cord, and showed that VPA protected spinal motoneurons against death from glutamate toxicity in vitro. Then, we treated ALS model mice with VPA at the dose effective level for epileptic model mice after 45 days of age (pre-onset treatment) or the day of the disease onset (post-onset treatment). We found a significant prolongation of the disease duration in ALS model mice in both methods of treatment. Considering the long usage of VPA for epileptic patients with good tolerance and safety, these data strongly support the clinical application of VPA for ALS treatment.

Hepatoma-derived growth factor is a neurotrophic factor harbored in the nucleus.

Hepatoma-derived growth factor (HDGF) is a heparin-binding proliferating factor originally isolated from conditioned medium of the hepatoma-derived cell line HuH-7. HDGF has greatest homology in an amino acid sequence with high mobility group 1 (HMG1), which has been characterized as a DNA-binding, inflammatory, and potent neurite outgrowth molecule. HDGF is reported to be widely expressed and act as a growth factor in many kinds of cells. However, it has not been investigated in the nervous system. Here, we show by Western blot analysis that HDGF is present in the mouse brain from the embryonic period until adulthood. In situ hybridization and immunohistochemical analyses revealed that HDGF was expressed mainly in neurons, and HDGF protein was localized to the nucleus. HDGF and high mobility group 1 were secreted under physiological conditions and released extracellularly in necrotic conditions. Furthermore, we showed that exogenously supplied HDGF had a neurotrophic effect and was able to partially prevent the cell death of neurons in which endogenous HDGF was suppressed. Therefore, we propose that HDGF is a novel type of neurotrophic factor, on account of its localization in the nucleus and its potential to function in an autocrine manner under both physiological and pathological conditions throughout life.