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Objectives: This study aimed to clarify the relationship between 43-kDa TAR DNA-binding protein (TDP-43) pathology and spinal cord anterior horn motor neuron (AHMN) atrophy in sporadic amyotrophic lateral sclerosis (SALS)., Methods: Eight patients with SALS and 12 controls were included in this study. Formalin-fixed specimens of lumbar spinal cord samples were paraffin-embedded and sectioned at the level of the fourth lumbar spinal cord with a 4 μm thickness. Using a microscope, the long diameters of the neurons with nucleoli were measured in spinal AHMNs stained with an anti-SMI-32 antibody. AHMNs were divided into medial and lateral nuclei for statistical analysis. We also used previously reported data to measure the long diameter of AHMNs with initial TDP-43 pathology, in which TDP-43 was present both in the nucleus and cytoplasm., Results: The long diameter of the lumbar spinal AHMNs in patients with SALS was smaller in the medial nucleus (42.54 ± 9.33 μm, n = 24) and the lateral nucleus (49.41 ± 13.86 μm, n = 129) than in controls (medial nucleus: 55.84 ± 13.49 μm, n = 85, p < 0.001; lateral nucleus: 62.39 ± 13.29 μm, n = 756, p < 0.001, Mann-Whitney U test). All 21 motor neurons with initial TDP-43 pathology were in the lateral nucleus, and their long diameter (67.60 ± 18.3 μm, p = 0.352) was not significantly different from that of controls., Conclusion: Motor neuron atrophy in SALS does not occur during the initial stages of TDP-43 pathology, and TDP-43 pathology is already advanced in the atrophied motor neurons., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Patients with amyotrophic lateral sclerosis (ALS) do not develop oculomotor disturbances and vesicorectal dysfunction until end-stage disease owing to the survival of certain motor neurons (MNs), including oculomotor neurons and MNs within Onuf's nucleus. In sporadic ALS, adenosine deaminase acting on RNA 2 (ADAR2)-mediated editing of GluA2 mRNA at the Q/R site is compromised in lower MNs. We previously developed genetically modified mice with a conditional knockout of ADAR2 in cholinergic neurons (ADAR2 flox/flox /VAChT-Cre, Fast; AR2). These mice displayed slow and progressive lower motor neuron death with TAR DNA-binding protein 43 (TDP-43) pathology, attributable to insufficient editing at the GluA2 Q/R site due to ADAR2 deficiency. MN death was more common in fast-fatigable MNs owing to differential vulnerability under conditions of ADAR2 deficiency. Although facial and hypoglossal nerves were impaired in AR2 mice, cell death did not occur within the oculomotor nerve nucleus, as observed in patients with sporadic ALS. Since the basis for avoiding cystorectal damage in ALS is unknown, we compared the features of Onuf's nucleus MNs in 12-month-old AR2 mice with those in age-matched wild-type mice. Although the number of MNs was not significantly lower in AR2 mice, the neurons exhibited a shrunken morphology and TDP-43 pathology. Onuf's nucleus MNs could survive in an ADAR2-deficient state and mainly included fast fatigue-resistant (FR) and slow (S) MNs. In summary, FR and S MNs show increased resilience to ADAR2 deficiency, potentially participating in an important neuronal death avoidance mechanism in ALS., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

We report a case of anticoagulation therapy complicated by a non-traumatic rectus sheath hematoma (RSH). RSH is a relatively rare occurrence caused by bleeding into the rectus sheath following the rupture of the superior and inferior epigastric vessels combined with a primary tear of the rectus muscle fibers. Herein, we report a rare presentation of RSH in a 73-year-old man taking the direct oral anticoagulant (DOAC) apixaban orally. The patient presented with sudden right abdominal pain after a severe cough, which worsened with cough and movement. The Fothergill and Carnett signs were positive. The platelet count, renal function test, and the prothrombin time/international normalized ratio were within the normal range. The activated partial thromboplastin time was 40.0 s, slightly longer than normal. Computed tomography (CT) of the abdomen and pelvis showed RSH, and DOAC therapy was temporarily discontinued. Subsequently, RSH resolution was confirmed via CT four weeks after the onset. DOACs are safer and more efficacious than warfarin for patients with non-valvular atrial fibrillation. However, RSH is a potential complication of anticoagulant therapy. This case report demonstrates that RSH should be considered in the differential diagnosis of sudden-onset abdominal pain and mass in patients on DOACs., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Hideyama et al.)

Background and Purpose: To clarify the effect of perampanel (PER) on sporadic amyotrophic lateral sclerosis (sALS) progression, the relationship between the changes in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) scores and serum PER concentrations was investigated., Methods: 12 patients with sALS from our hospital who agreed to participate and completed the PER for sALS randomized phase 2 study were included. After completing the study, we retrospectively obtained serum PER concentration data from the patients. Based on their mean PER concentrations, we divided the patients who had been taking PER into two groups: four patients with a mean PER concentration of ≥400 ng/mL were assigned to the H group, and three with a mean PER concentration of <400 ng/mL were assigned to the L group. The control group consisted of five patients who had been taking a placebo. We obtained the ALSFRS-R scores of each patient at 36 and 48 weeks after randomization. The differences in ALSFRS-R scores at baseline (0 weeks) and each subsequent week were used in the analysis., Results: At 48 weeks, there were no differences in the degree of deterioration of the bulbar, upper and lower limb, and respiratory ALSFRS-R subscores and total ALSFRS-R score. However, at 36 weeks, the bulbar subscore was significantly lower in the H group than in the control group ( p =0.032)., Conclusions: Because high PER concentrations may exacerbate bulbar symptoms in patients with sALS, serum PER measurements may be beneficial when patients with sALS are taking PER., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2023 Korean Neurological Association.)

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the selective degeneration of motor neurons (MNs). In the MNs of patients with ALS, adenosine deaminase acting on RNA 2 (ADAR2)-mediated RNA editing of GluA2 mRNA at the Q/R site is profoundly deficient. In genetically modified mice (ADAR2 flox/flox /VAChT-Cre.Fast; AR2), the selective knockout of ADAR2 in cholinergic neurons induced progressive loss of lower MNs. MNs exhibiting an age-related increase in abnormal TDP-43 localization and reduced ADAR2 immunoreactivity are localized in the lateral areas of the anterior horns (AHs) in aged wild-type mice. However, the patterns in the AHs of AR2 mice remain unknown. In this study, we investigated whether similar degeneration is observed in AR2 mice. We compared the number of astrocytes and MNs in the lateral and medial AHs of the lumbar spinal cord of 12-month-old AR2 mice with age-matched wild-type mice. The number of MNs significantly decreased in both the lateral and medial areas in AR2 mice AHs, particularly in the former. The number of reactive astrocytes increased significantly in the lateral areas of the AHs of AR2 mice. In conclusion, stronger activation of astrocytes with reduction of MNs in the ADAR2 deficiency-related lateral area increases in AR2 mice AHs. Fast fatigable MNs are expected to be present in the lateral area of the AHs. We found that MN death is more common in the lateral area of AHs associated with FF MNs due to differences in vulnerability to MN under ADAR2 deficiency., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022. Published by Elsevier B.V.)

Background and Purpose: Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease. Selective deficiency of edited adenosine deaminase acting on RNA 2 (ADAR2), a key molecule in the acquisition of Ca 2+ resistance in motor neurons, has been reported in sporadic ALS (sALS) spinal motor neurons. Since ADAR2 activity is positively regulated by prolyl isomerase Protein never in mitosis gene A interacting-1 (Pin1), a known phosphorylation-dependent peptidyl-prolyl cis/trans isomerase, we investigated Pin1 expression in spinal motor neurons in sALS., Methods: Specimens of the spinal cord were obtained from the lumbar region in eight sALS patients and age-matched five controls after postmortem examinations. The specimens were double stained with anti-Pin1 and anti-TAR DNA-binding protein of 43 kDa (TDP-43) antibodies, and examined under a fluorescence microscope., Results: This study analyzed 254 and 422 spinal motor neurons from 8 sALS patients and 5 control subjects, respectively. The frequency of motor neurons with high cytoplasmic Pin1 expression from the spinal cord did not differ significantly between sALS specimens without cytoplasmic TDP-43 inclusions and control specimens. However, in sALS specimens, neurons for which the Pin1 immunoluminescence intensity in the cytoplasm was at least twice that in the background were more common in specimens with cytoplasmic TDP-43 inclusions ( p <0.05 in χ² test)., Conclusions: In sALS, neurons with higher expression levels of Pin1 levels had more TDP-43 inclusions. Despite the feedback mechanism between Pin1 and ADAR2 being unclear, since Pin1 positively regulates ADAR2, our results suggest that higher Pin1 expression levels in motor neurons with TDP-43 pathology from sALS patients represent a compensatory mechanism., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2022 Korean Neurological Association.)

Importance: Repeat expansion of CGG in LRP12 has been identified as the causative variation of oculopharyngodistal myopathy (OPDM). However, to our knowledge, the clinicopathologic features of OPDM with CGG repeat expansion in LRP12 (hereafter referred to as OPDM&#95;LRP12) remain unknown., Objective: To identify and characterize the clinicopathologic features of patients with OPDM&#95;LRP12., Design, Setting, and Participants: This case series included 208 patients with a clinical or clinicopathologic diagnosis of oculopharyngeal muscular dystrophy (OPDM) from January 1, 1978, to December 31, 2020. Patients with GCN repeat expansions in PABPN1 were excluded from the study. Repeat expansions of CGG in LRP12 were screened by repeat primed polymerase chain reaction and/or Southern blot., Main Outcomes and Measures: Clinical information, muscle imaging data obtained by either computed tomography or magnetic resonance imaging, and muscle pathologic characteristics., Results: Sixty-five Japanese patients with OPDM (40 men [62%]; mean [SD] age at onset, 41.0 [10.1] years) from 59 families with CGG repeat expansions in LRP12 were identified. This represents the most common OPDM subtype among all patients in Japan with genetically diagnosed OPDM. The expansions ranged from 85 to 289 repeats. A negative correlation was observed between the repeat size and the age at onset (r2 = 0.188, P = .001). The most common initial symptoms were ptosis and muscle weakness, present in 24 patients (37%). Limb muscle weakness was predominantly distal in 53 of 64 patients (83%), but 2 of 64 patients (3%) had predominantly proximal muscle weakness. Ptosis was observed in 62 of 64 patients (97%), and dysphagia or dysarthria was observed in 63 of 64 patients (98%). A total of 21 of 64 patients (33%) had asymmetric muscle weakness. Aspiration pneumonia was seen in 11 of 64 patients (17%), and 5 of 64 patients (8%) required mechanical ventilation. Seven of 64 patients (11%) developed cardiac abnormalities, and 5 of 64 patients (8%) developed neurologic abnormalities. Asymmetric muscle involvement was detected on computed tomography scans in 6 of 27 patients (22%) and on magnetic resonance imaging scans in 4 of 15 patients (27%), with the soleus and the medial head of the gastrocnemius being the worst affected. All 42 muscle biopsy samples showed rimmed vacuoles. Intranuclear tubulofilamentous inclusions were observed in only 1 of 5 patients., Conclusions and Relevance: This study suggests that OPDM&#95;LRP12 is the most frequent OPDM subtype in Japan and is characterized by oculopharyngeal weakness, distal myopathy that especially affects the soleus and gastrocnemius muscles, and rimmed vacuoles in muscle biopsy.

Spontaneous intracranial hypotension (SIH) is an important cause of headache mainly associated with spinal cerebrospinal fluid leakage. We herein report the case of a 51-year-old man who developed SIH after swimming. Brain magnetic resonance imaging (MRI) showed a transient high-intensity lesion in the splenium of the corpus callosum (SCC), in addition to bilateral subdural hematomas (SDH) and pseudo-subarachnoid hemorrhage on brain computed tomography. The splenial lesion disappeared and SDH improved after an epidural blood patch. This case emphasizes that transient SCC lesions could coexist with SIH and that SIH should be considered in the differential diagnosis of SCC lesions.

Corticobasal degeneration (CBD) is a rare progressive neurodegenerative disorder characterized by asymmetric presentation of cerebral cortex signs, cortical sensory disturbance and extrapyramidal signs. Herein, we report a case of a 66-year-old Japanese woman who presented with apraxia of the right hand. She subsequently developed postural instability and cognitive impairments that rapidly worsened. One and a half years later, the patient was wheelchair-bound and severely demented. Brain magnetic resonance imaging revealed left dominant atrophy of the frontoparietal lobe. There was a hyperintense lesion in the deep white matter expanding toward the subcortical area on fluid-attenuated inversion recovery (FLAIR) images. In order to rule out the possibility of an intracranial tumor such as an astrocytoma or malignant lymphoma, we performed a brain biopsy of the left frontal middle gyrus. The patient became bedridden and showed akinetic mutism 1 year after biopsy. Pathological examination revealed a large amount of 4-repeat tau-immunoreactive neuropil threads scattered predominantly in the corticomedullary junction and tau-immunoreactive structures, consistent with CBD. Immunostaining for p53 showed no positive cells, and there were very few Ki-67-positive cells. On immunoblots of sarkosyl-insoluble brain extracts, a major doublet of 64 and 68 kDa full-length tau with two closely related fragments of approximately 37 kDa were detected. Based on these results, the patient was pathologically diagnosed as having CBD, excluding the possibility of tumor. Taken together with previous similar case reports, our findings indicate that a deep white matter hyperintense lesion on FLAIR images may be a useful clue to CBD, predicting rapid clinical progression with severe dementia based on severe white matter degeneration with a large amount of tau accumulation on pathological examination., (© 2020 Japanese Society of Neuropathology.)

"Stroke mimics" mean diseases presenting with acute neurological impairments that are taken for stroke. Discriminating them is crucial to avoid improper treatment or delayed correct treatment. We describe a 48-year-old woman presenting with a sudden onset of scintillating scotoma and left-lower quadrantanopsia. Hyperacute cerebral infarction was suspected. However, brain magnetic resonance imaging (MRI) revealed a mass at the cortico-medullary junction in the right occipital lobe. We diagnosed her as metastatic melanoma. We suspected that neurological deficits can be attributed to seizure, and therefore introduced levetiracetam. She showed neurological improvement immediately. Our case demonstrated the importance of considering brain tumor as a differential diagnosis in patients presenting with acute-onset neurological deficits. In addition to appropriate treatment of tumor, the use of newer antiepileptic drugs resulted in good neurological prognosis in metastatic brain tumors., Competing Interests: Dr Narita has received an honorarium from Chugai Pharmaceutical Co., Ltd and conducted contract research with AbbVie GK, Ono Pharmaceutical Co., Ltd., Stella Pharma Co., Ltd., Sumitomo Heavy Industries, Ltd., and Nihon Medi‐Physics Co., Ltd. The other authors state that they have no conflict of interest. All the authors state they have no conflict of interest with Otsuka Pharmaceutical Co., Ltd. or UCB Japan Co. Ltd, the distributor of levetiracetam., (© 2020 The Authors. Journal of General and Family Medicine published by John Wiley & Sons Australia, Ltd on behalf of Japan Primary Care Association.)

Tumefactive demyelinating lesions (TDLs) are rare in multiple sclerosis (MS). We herein report a case of tumefactive MS which initially presented with brainstem encephalitis with a long-term follow-up. The patient had experienced relapse mostly in the brainstem in the first twenty years, and then in the periventricular white matter afterwards. The patient responded well to steroid treatment recovered without sequalae. However, immunodeficiency due to the long-term use of oral prednisolone made aggressive therapy during the relapse impossible, so recovery after steroid therapy is incomplete. Our case is different from classical MS in clinical course and response to treatment. Our report offers rare information on long-term outcome of tumefactive MS., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The case is a 75-year-old female. She had dysesthesia in the distal extremities and truncal ataxia, and they had progressed in two months. Neurological examination revealed the findings of segmental dysesthesia in the distal extremities, impaired deep sensations in the trunk and four limbs, and painful legs and moving toes (PLMT). After workup, she was diagnosed with small cell lung cancer and her blood sample was positive for anti-Hu antibody. We concluded that her neurological symptoms were attributable to sensory neuronopathy associated with paraneoplastic syndrome. No cases with PLMT caused by paraneoplastic syndrome have been reported so far. She had chemotherapy to lung cancer and Duloxetine without improvement of PLMT. On the other hand, intravenous immunoglobulin treatment improved lightening pain in the toes without improvement of moving toes.

Segmental zoster paresis is an uncommon complication of herpes zoster, and abdominal wall pseudohernia is rare. Previous reports have emphasized the involvement of anterior rami of spinal nerves, while the involvement of posterior rami has been less frequently reported. We aimed to elucidate the involvement of posterior rami of spinal nerves in abdominal wall pseudohernia. Four patients with a diagnosis of abdominal wall pseudohernia underwent needle electromyography (nEMG) and magnetic resonance imaging (MRI). In three patients, nEMG of affected paraspinal muscles showed denervation potentials, and MRI showed hyperintensity of these muscles on short T1 inversion recovery imaging. These results suggested involvement of paraspinal muscles, and indicated that posterior rami of spinal nerves are also often affected in abdominal wall pseudohernia. MRI as well as nEMG could be useful for evaluating paraspinal muscle involvement and for the diagnosis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Systemic lupus erythematosus (SLE) is a multisystem disorder, which occurs mostly in young women. However, late-onset SLE does exist and sometimes presents with an atypical, diversified course. We describe an 85-year-old woman who was admitted to our hospital for lower extremity edema and hand grip weakness. Chest computed tomography scan 4 days after admission demonstrated rapid accumulation of pleural and pericardial effusions, which did not exist on admission. She was diagnosed with pleuritis and pericarditis associated with very-late-onset SLE. Methylprednisolone pulse therapy resulted in a drastic improvement in serositis. Our case exemplifies the fact that patients with late-onset SLE sometimes follow an atypical course, which makes the clinical diagnosis difficult.

Mutations in the fused in sarcoma (FUS) gene can cause amyotrophic lateral sclerosis (ALS), and FUS gene mutations have been reported in sporadic ALS patients with basophilic cytoplasmic inclusions. Deficiency of adenosine deaminase acting on RNA 2 (ADAR2), an enzyme that specifically catalyzes GluA2 Q/R site-editing, has been reported in considerable proportions of spinal motor neurons of the majority of sporadic ALS patients. We describe the relationship between GluA2 Q/R site-editing efficiency and FUS-positive inclusions in a patient with FUS(P525L). A 24-year-old woman with ALS presented with basophilic cytoplasmic inclusions, significantly reduced GluA2 Q/R site-editing efficiency in the spinal motor neurons, and markedly decreased ADAR2 mRNA levels. Neuropathologic examination showed that not all spinal motor neurons expressed ADAR2 and revealed FUS-positive cytoplasmic inclusions in motor neurons irrespective of ADAR2 immunoreactivity. There were no phosphorylated transactive response (TAR) DNA-binding protein 43 kDa (TDP-43)-positive inclusions, indicating that there was no tight correlation between ADAR2 deficiency and TDP-43 deposition. ADAR2 deficiency can occur in ALS patients with a FUS(P525L) mutation and is unrelated to the presence of FUS-positive inclusions. FUS-associated ALS may share neurodegenerative characteristics with classical sporadic ALS., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

We herein describe a rare case of temporal arteritis associated with hypertrophic pachymeningitis. An 81-year-old man presented with a right temporal headache that had persisted for one month. A right superficial temporal artery biopsy revealed intimal hypertrophy with increased elastic fibers, consistent with temporal arteritis. Brain MRI using gadolinium enhancement showed thickened dura mater on the right frontal and temporal lobes, which led to the diagnosis of hypertrophic pachymeningitis. Intravenous methylprednisolone and oral prednisolone improved the patient's symptoms. According to our findings, hypertrophic pachymeningitis may be a potential cause of an ipsilateral temporal headache associated with temporal arteritis.

A 78-year-old woman with a history of bronchial asthma presented with distal dominant sensory disturbance and weakness in the upper and lower extremities. A biopsy of the left peroneus brevis muscle showed active vasculitis with inflammation extending into muscle fascicles and fibrinoid necrosis of the vessel wall, consistent with eosinophilic granulomatosis with polyangiitis (EGPA). Despite her decreased serum osmolarity, her serum antidiuretic hormone level was not reduced, consistent with the syndrome of inappropriate antidiuretic hormone (SIADH). Intravenous and oral steroid therapy improved her neurological symptoms. Clinicians should consider EGPA as a concurrent, and potentially causative, disorder in cases of SIADH.

A reduction in adenosine deaminase acting on RNA 2 (ADAR2) activity causes the death of spinal motor neurons specifically via the GluA2 Q/R site-RNA editing failure in sporadic amyotrophic lateral sclerosis (ALS). We studied, over time, the spinal cords of ADAR2-knockout mice, which are the mechanistic model mice for sporadic ALS, using homozygous ADAR2(flox/flox)/VAChT-Cre.Fast (AR2), homozygous ADAR2(flox/flox)/VAChT-Cre.Slow (AR2Slow), and heterozygous ADAR2(flox/+)/VAChT-Cre.Fast (AR2H) mice. The conditional ADAR2-knockout mice were divided into 3 groups by stage: presymptomatic (AR2H mice), early symptomatic (AR2 mice, AR2H mice) and late symptomatic (AR2Slow mice). Light-microscopically, some motor neurons in AR2 and AR2H mice (presymptomatic) showed simple neuronal atrophy and astrogliosis, and AR2H (early symptomatic) and AR2Slow mice often showed vacuoles predominantly in motor neurons. The number of vacuole-bearing anterior horn neurons decreased with the loss of anterior horn neurons in AR2H mice after 40 weeks of age. Electron-microscopically, in AR2 mice, while the cytoplasm of normal-looking motor neurons was almost always normal-appearing, the interior of dendrites was frequently loose and disorganized. In AR2H and AR2Slow mice, large vacuoles without a limiting membrane were observed in the anterior horns, preferentially in the nuclei of motor neurons, astrocytes and oligodendrocytes. Nuclear vacuoles were not observed in AR2res (ADAR2(flox/flox)/VAChT-Cre.Fast/GluR-B(R/R)) mice, in which motor neurons express edited GluA2 in the absence of ADAR2. These findings suggest that ADAR2-reduction is associated with progressive deterioration of nuclear architecture, resulting in vacuolated nuclei due to a Ca(2+)-permeable AMPA receptor-mediated mechanism., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A 43-year-old man was admitted to our hospital because of diplopia, ptosis, and dysphagia that had begun three years previously. He was diagnosed with myasthenia gravis (MG) and invasive thymoma and treated with corticosteroid, thymectomy, and radiation therapy. Ten years after the thymectomy, computed tomography (CT) showed metastasis of the thymoma in the left lower lobe of the lung. Two years after this recurrence, when the patient was 55, respiratory symptoms such as wheezing, persistent cough, and dyspnea appeared. Chronic sinusitis, diffuse centrilobular opacities on CT, and positivity for HLA-B54 led to a diagnosis of diffuse panbronchiolitis (DPB). Despite treatment with clarithromycin, the respiratory symptoms worsened. The patient developed alopecia and body hair loss at the age of 56 followed by dysgeusia, cholangitis, and myositis with positivity for anti-Kv1.4 antibodies. Although treatment with an increased dose of corticosteroid improved hair loss, dysgeusia, cholangitis, and myositis, he died of progression of DPB and serious respiratory infection at the age of 58. In this case, various autoimmune disorders occurred together with MG as complications of thymoma. Although alopecia, dysgeusia, and myositis are already known as complications of MG associated with thymoma, cholangitis is not well-recognized since there have been few reports suggesting a causal relationship between cholangitis and thymoma. Furthermore, DPB caused by immunodeficiency and respiratory tract hypersensitivity associated with thymoma and HLA-B54, respectively, is the distinctive feature of our case. Neurologists should be aware that various organs can be damaged directly and indirectly by abnormal T cells from thymoma in patients with MG.

TDP-43 pathology in motor neurons is a hallmark of ALS. In addition, the reduced expression of an RNA editing enzyme, adenosine deaminase acting on RNA 2 (ADAR2), increases the expression of GluA2 with an unedited Q/R site in the motor neurons of patients with sporadic ALS. As the occurrence of these two disease-specific abnormalities in the same motor neurons suggests a molecular link between them, we examined the effects of altered TDP-43 processing on ADAR2 activity in TetHeLaG2m and Neuro2a cells. We found that ADAR2 activity did not consistently change due to the overexpression or knockdown of TDP-43 or the expression of abnormal TDP-43, including caspase-3-cleaved fragments, truncated TDP-43 lacking either nuclear localization or export signals and ALS-linked TDP-43 mutants. These results suggest that the abnormal processing of TDP-43 is not an upstream event of inefficient GluA2 Q/R site editing in the motor neurons of sporadic ALS patients., (Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Adenosine deaminase acting on RNA 2 (ADAR2) catalyzes RNA editing at the glutamine/arginine (Q/R) site of GluA2, and an ADAR2 deficiency may play a role in the death of motor neurons in ALS patients. The expression level of ADAR2 mRNA is a determinant of the editing activity at the GluA2 Q/R site in human brain but not in cultured cells. Therefore, we investigated the extent of Q/R site-editing in the GluA2 mRNA and pre-mRNA as well as the ADAR2 mRNA and GluA2 mRNA and pre-mRNA levels in various cultured cell lines. The extent of the GluA2 mRNA editing was 100% except in SH-SY5Y cells, which have a much lower level of ADAR2 than the other cell lines examined. The ADAR2 activity at the GluA2 pre-mRNA Q/R site correlated with the ADAR2 mRNA level relative to the GluA2 pre-mRNA. SH-SY5Y cells expressed higher level of the GluA2 mRNA in the cytoplasm compared with other cell lines. These results suggest that the ADAR2 expression level reflects editing activity at the GluA2 Q/R site and that although the edited GluA2 pre-mRNA is readily spliced, the unedited GluA2 pre-mRNA is also spliced and transported to the cytoplasm when ADAR2 expression is low., (Copyright © 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.)

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset fatal motor neuron disease. In spinal motor neurons of patients with sporadic ALS, normal RNA editing of GluA2, a subunit of the L-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor, is inefficient. Adenosine deaminase acting on RNA 2 (ADAR2) specifically mediates RNA editing at the glutamine/arginine (Q/R) site of GluA2 and motor neurons expressing Q/R site-unedited GluA2 undergo slow death in conditional ADAR2 knockout mice. Therefore, investigation into whether inefficient ADAR2-mediated GluA2 Q/R site-editing occurs universally in motor neurons of patients with ALS would provide insight into the pathogenesis of ALS. We analyzed the extents of GluA2 Q/R site-editing in an individual laser-captured motor neuron of 29 ALS patients compared with those of normal and disease control subjects. In addition, we analyzed the enzymatic activity of three members of the ADAR family (ADAR1, ADAR2 and ADAR3) in ALS motor neurons expressing unedited GluA2 mRNA and those expressing only edited GluA2 mRNA. Q/R site-unedited GluA2 mRNA was expressed in a significant proportion of motor neurons from all of the ALS cases examined. Conversely, motor neurons of the normal and disease control subjects expressed only edited GluA2 mRNA. ADAR2, but not ADAR1 or ADAR3, was significantly downregulated in all the motor neurons of ALS patients, more extensively in those expressing Q/R site-unedited GluA2 mRNA than those expressing only Q/R site-edited GluA2 mRNA. These results indicate that ADAR2 downregulation is a profound pathological change relevant to death of motor neurons in ALS., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Both mislocalization of TDP-43 and downregulation of RNA-editing enzyme ADAR2 co-localize in the motor neurons of amyotrophic lateral sclerosis patients, but how they are linked is not clear. Here we demonstrate that activation of calpain, a Ca2+-dependent cysteine protease, by upregulation of Ca2+-permeable AMPA receptors generates carboxy-terminal-cleaved TDP-43 fragments and causes mislocalization of TDP-43 in the motor neurons expressing glutamine/arginine site-unedited GluA2 of conditional ADAR2 knockout (AR2) mice that mimic the amyotrophic lateral sclerosis pathology. These abnormalities are inhibited in the AR2res mice that express Ca2+-impermeable AMPA receptors in the absence of ADAR2 and in the calpastatin transgenic mice, but are exaggerated in the calpastatin knockout mice. Additional demonstration of calpain-dependent TDP43 fragments in the spinal cord and brain of amyotrophic lateral sclerosis patients, and high vulnerability of amyotrophic lateral sclerosis-linked mutant TDP43 to cleavage by calpain support the crucial role of the calpain-dependent cleavage of TDP43 in the amyotrophic lateral sclerosis pathology.

TDP-43 pathology in spinal motor neurons is a neuropathological hallmark of sporadic amyotrophic lateral sclerosis (ALS) and has recently been shown to be closely associated with the downregulation of an RNA editing enzyme called adenosine deaminase acting on RNA 2 (ADAR2) in the motor neurons of sporadic ALS patients. Because TDP-43 pathology is found more frequently in the brains of elderly patients, we investigated the age-related changes in the TDP-43 localization and ADAR2 activity in mouse motor neurons. We found that ADAR2 was developmentally upregulated, and its mRNA expression level was progressively decreased in the spinal cords of aged mice. Motor neurons normally exhibit nuclear ADAR2 and TDP-43 immunoreactivity, whereas fast fatigable motor neurons in aged mice demonstrated a loss of ADAR2 and abnormal TDP-43 localization. Importantly, these motor neurons expressed significant amounts of the Q/R site-unedited AMPA receptor subunit 2 (GluA2) mRNA. Because expression of unedited GluA2 has been demonstrated as a lethality-causing molecular abnormality observed in the motor neurons, these results suggest that age-related decreases in ADAR2 activity play a mechanistic role in aging and serve as one of risk factors for ALS.

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. More than 90% of ALS cases are sporadic, and the majority of sporadic ALS patients do not carry mutations in genes causative of familial ALS; therefore, investigation specifically targeting sporadic ALS is needed to discover the pathogenesis. The motor neurons of sporadic ALS patients express unedited GluA2 mRNA at the Q/R site in a disease-specific and motor neuron-selective manner. GluA2 is a subunit of the AMPA receptor, and it has a regulatory role in the Ca(2+)-permeability of the AMPA receptor after the genomic Q codon is replaced with the R codon in mRNA by adenosine-inosine conversion, which is mediated by adenosine deaminase acting on RNA 2 (ADAR2). Therefore, ADAR2 activity may not be sufficient to edit all GluA2 mRNA expressed in the motor neurons of ALS patients. To investigate whether deficient ADAR2 activity plays pathogenic roles in sporadic ALS, we generated genetically modified mice (AR2) in which the ADAR2 gene was conditionally knocked out in the motor neurons. AR2 mice showed an ALS-like phenotype with the death of ADAR2-lacking motor neurons. Notably, the motor neurons deficient in ADAR2 survived when they expressed only edited GluA2 in AR2/GluR-B(R/R) (AR2res) mice, in which the endogenous GluA2 alleles were replaced by the GluR-B(R) allele that encoded edited GluA2. In heterozygous AR2 mice with only one ADAR2 allele, approximately 20% of the spinal motor neurons expressed unedited GluA2 and underwent degeneration, indicating that half-normal ADAR2 activity is not sufficient to edit all GluA2 expressed in motor neurons. It is likely therefore that the expression of unedited GluA2 causes the death of motor neurons in sporadic ALS. We hypothesize that a progressive downregulation of ADAR2 activity plays a critical role in the pathogenesis of sporadic ALS and that the pathological process commences when motor neurons express unedited GluA2.

GluR2 is a subunit of the AMPA receptor, and the adenosine for the Q/R site of its pre-mRNA is converted to inosine (A-to-I conversion) by the enzyme called adenosine deaminase acting on RNA 2 (ADAR2). Failure of A-to-I conversion at this site affects multiple AMPA receptor properties, including the Ca(2+) permeability of the receptor-coupled ion channel, thereby inducing fatal epilepsy in mice (Brusa et al., 1995; Feldmeyer et al., 1999). In addition, inefficient GluR2 Q/R site editing is a disease-specific molecular dysfunction found in the motor neurons of sporadic amyotrophic lateral sclerosis (ALS) patients (Kawahara et al., 2004). Here, we generated genetically modified mice (designated as AR2) in which the ADAR2 gene was conditionally targeted in motor neurons using the Cre/loxP system. These AR2 mice showed a decline in motor function commensurate with the slow death of ADAR2-deficient motor neurons in the spinal cord and cranial motor nerve nuclei. Notably, neurons in nuclei of oculomotor nerves, which often escape degeneration in ALS, were not decreased in number despite a significant decrease in GluR2 Q/R site editing. All cellular and phenotypic changes in AR2 mice were prevented when the mice carried endogenous GluR2 alleles engineered to express edited GluR2 without ADAR2 activity (Higuchi et al., 2000). Thus, loss of ADAR2 activity causes AMPA receptor-mediated death of motor neurons.

Both the appearance of cytoplasmic inclusions containing phosphorylated TAR DNA-binding protein (TDP-43) and inefficient RNA editing at the GluR2 Q/R site are molecular abnormalities observed specifically in motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS). The purpose of this study is to determine whether a link exists between these two specific molecular changes in ALS spinal motor neurons. We immunohistochemically examined the expression of adenosine deaminase acting on RNA 2 (ADAR2), the enzyme that specifically catalyzes GluR2 Q/R site-editing, and the expression of phosphorylated and non-phosphorylated TDP-43 in the spinal motor neurons of patients with sporadic ALS. We found that all motor neurons were ADAR2-positive in the control cases, whereas more than half of them were ADAR2-negative in the ALS cases. All ADAR2-negative neurons had cytoplasmic inclusions that were immunoreactive to phosphorylated TDP-43, but lacked non-phosphorylated TDP-43 in the nucleus. Our results suggest a molecular link between reduced ADAR2 activity and TDP-43 pathology.

alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor-mediated excitotoxicity has been proposed to play a role in death of motor neurons in amyotrophic lateral sclerosis (ALS). We demonstrated that RNA editing of GluR2 mRNA at the glutamine/arginine (Q/R) site was decreased in autopsy-obtained spinal motor neurons, but not in cerebellar Purkinje cells, of patients with sporadic ALS. This molecular change occurs in motor neurons of sporadic ALS cases with various phenotypes, but not in degenerating neurons of patients with other neurodegenerative diseases, including SOD1-associated familial ALS. Because GluR2 Q/R site-editing is specifically catalyzed by adenosine deaminase acting on RNA 2 (ADAR2), it is likely that regulatory mechanism of ADAR2 activity does not work well in the motor neurons of sporadic ALS. Indeed, ADAR2 expression level was significantly decreased in the spinal ventral gray matter of sporadic ALS as compared to normal control subjects. It is likely that ADAR2 underactivity selective in motor neurons induced deficient GluR2 Q/R site-editing, which results in the neuronal death of sporadic ALS. Thus, among multiple different molecular mechanisms underlying death of motor neurons, it is likely that an increase of the proportion of Q/R site-unedited GluR2-containing Ca(2+)-permeable AMPA receptors initiates the death of motor neurons in sporadic ALS. To this end, normalization of ADAR2 activity in motor neurons may become a therapeutic strategy for sporadic ALS.

The motor neurons of patients with sporadic amyotrophic lateral sclerosis (ALS) express abundant Q/R site-unedited GluR2 mRNA, whereas those of patients with other motor neuron diseases including familial ALS associated with mutated SOD1 (ALS1) and those of normal subjects express only Q/R site-edited GluR2 mRNA. Because adenosine deaminase acting on RNA type 2 (ADAR2) specifically catalyzes GluR2 Q/R site-editing, it is likely that ADAR2 activity is not sufficient to edit this site completely in motor neurons of patients with sporadic ALS. Because these molecular abnormalities occur in disease- and motor neuron-specific fashion and induce fatal epilepsy in mice, we have hypothesized that GluR2 Q/R site-underediting due to ADAR2 underactivity is a cause of neuronal death in sporadic ALS. We found that cytoplasmic fragile X mental retardation protein interacting protein 2 (CYFIP2) mRNA had an ADAR2-mediated editing position using RNA interference knockdown. Our review will include a discussion of new ADAR2 substrates that may be useful for research on sporadic ALS.

A 73-year-old woman was admitted to the surgical department of our hospital for endoscopic resection of a colonic polyp. The day after endoscopic resection, she became drowsy and dysphasic. Two days later, left hemiparesis and gait difficulty developed. The next day, hemiparesis progressed bilaterally and dyspnea developed due to upper airway stenosis. The most prominent signs were those of bulbar palsy. Blood analysis revealed mild inflammatory responses and hyponatremia. T2-weighted magnetic resonance imaging showed high-intensity lesions in the swollen medulla and cervical spinal cord. Those areas and the meninges of the posterior fossa were enhanced by gadolinium. Steroid pulse therapy was administered, resulting in rapid recovery of bulbar and paretic symptoms with decreased enhanced area. At this point, concentration of cerebrospinal fluid interleukin (IL)-10 was markedly elevated at 146 pg/ml (normal,< 5 pg/ml), suggesting malignant lymphoma. Cytology of the cerebrospinal fluid was repeatedly examined, eventually revealing atypical lymphocytes with hyperlobulated nuclei and clear nucleoli. Lymphocytes stained with anti-CD20 antibody. These findings strongly suggested a diagnosis of primary intraocular and central nervous system lymphoma. In the present case, repeated cytology of cerebrospinal fluid was highly important for diagnosis in this case of high IL-10 level in cerebrospinal fluid.

A-to-I RNA editing modifies a variety of biologically important mRNAs, and is specifically catalyzed by either adenosine deaminase acting on RNA type 1 (ADAR1) or type 2 (ADAR2) in mammals including human. Recently several novel A-to-I editing sites were identified in mRNAs abundantly expressed in mammalian organs by means of computational genomic analysis, but which enzyme catalyzes these editing sites has not been determined. Using RNA interference (RNAi) knockdowns, we found that cytoplasmic fragile X mental retardation protein interacting protein 2 (CYFIP2) mRNA had an ADAR2-mediated editing position and bladder cancer associated protein (BLCAP) mRNA had an ADAR1-mediated editing position. In addition, we found that ADAR2 forms a complex with mRNAs with ADAR2-mediated editing positions including GluR2, kv1.1 and CYFIP2 mRNAs, particularly when the editing sites were edited in human cerebellum by means of immunoprecipitation (IP) method. CYFIP2 mRNA was ubiquitously expressed in human tissues with variable extents of K/E site editing. Because ADAR2 underactivity may be a causative molecular change of death of motor neurons in sporadic amyotrophic lateral sclerosis (ALS), this newly identified ADAR2-mediated editing position may become a useful tool for ALS research.

Background: Patients with amyotrophic lateral sclerosis (ALS) sometimes exhibit parkinsonism, but the lesion responsible for parkinsonism has not been extensively studied., Objective: To test whether nigrostriatal system dysfunction is responsible for parkinsonism in ALS., Design: From the 182 ALS patients who were admitted to our neurology ward during the past 10 years, we extracted all the patients who satisfied the criteria of both parkinsonism and ALS., Setting: The University of Tokyo Hospital., Methods: We conducted [(18)F]L-dopa and [(11)C]N-methylspiperone positron emission tomography and technetium Tc 99m hexamethylpropyleneamine oxime single-photon emission computed tomography studies on 5 patients with ALS manifesting overt parkinsonism., Results: Two male and 3 female patients (average age, 63.2 +/- 5.8 years) had ALS for an average of 28.6 +/- 21.5 months and had parkinsonism for an average of 15.2 +/- 11.4 months. Features of their parkinsonism were characterized by outstanding bradykinesia without resting tremor or dementia. The results of positron emission tomography studies indicated normal nigrostriatal function, but those of single-photon emission computed tomography demonstrated decreased blood flow in the frontotemporal cortices., Conclusion: It is likely that parkinsonism in ALS is due to cortical lesions rather than nigrostriatal dysfunction and that both symptoms are the clinical manifestation of frontotemporal dementia with motor neuron diseases, including classic ALS.

Deficient RNA editing of the AMPA receptor subunit GluR2 at the Q/R site is a primary cause of neuronal death and recently has been reported to be a tightly linked etiological cause of motor neuron death in sporadic amyotrophic lateral sclerosis (ALS). We quantified the RNA editing efficiency of the GluR2 Q/R site in single motor neurons of rats transgenic for mutant human Cu/Zn-superoxide dismutase (SOD1) as well as patients with spinal and bulbar muscular atrophy (SBMA), and found that GluR2 mRNA was completely edited in all the motor neurons examined. It seems likely that the death cascade is different among the dying motor neurons in sporadic ALS, familial ALS with mutant SOD1 and SBMA.

A 95-year-old woman complained of sudden onset of disturbance of consciousness and right hemiparesis on April 20, 2003 and was admitted on the next day. She was drowsy and showed moderate right motor and sensory hemiparesis. The blood laboratory tests showed slight inflammatory reaction. A low density area was found in the left basal ganglia by brain CT, which was also coincided with the high signal region in T2, FLAIR and diffusion-MR images. The MRA of the intracerebral arteries presented no remarkable abnormality. The hemiparesis and impaired consciousness improved partially in the following week. However, she did not fully recover, since aspiration pneumonia and mild generalized inflammation continued. Percutaneous gastrostomy and intravenous hyperalimentation were started to improve her nutrition. The moderate inflammatory state persisted for several weeks. Her blood pressure suddenly fell and she died on June 12. Autopsy showed a mildly brownish and necrotic lesion from the left caudate to the putamen through the internal capsule. There was no liquefaction. On the microscopic examination, the necrosis surrounded by small vessels was consisted of numerous neutrophils and macrophages with pseudohypha and blastospore of candida. Small fragments of fungus were phagocytosed by macrophages. Small abscesses and necrotic foci due to candidiasis were observed in the bladder, kidneys, lungs, myocardium and thyroid gland. In this case, cerebral candidiasis probably occurred via hematogenous dissemination from a primary focus in the urinary tract. The intracerebral arteries revealed rather mild atherosclerotic changes and there was no occlusion by thromboembolism. Intracerebral lesion was diagnosed as candidiasis and there was no cerebral infarction by thromboembolism. If the infection occurred after cerebral infarction, there should not be any inflammatory reaction in the center of necrotic area. There have been few reports of cerebral candidal infection in patients without diabetes mellitus or immunosuppressive conditions. None of them had been diagnosed before death. Caution should be exercised for the presence of systemic candidiasis in elderly patients who are bedridden and with continuous low grade inflammatory reactions.