GPR137 Inhibits Cell Proliferation and Promotes Neuronal Differentiation in the Neuro2a Cells.

The orphan receptor, G protein-coupled receptor 137 (GPR137), is an integral membrane protein involved in several types of cancer. GPR137 is expressed ubiquitously, including in the central nervous system (CNS). We established a GPR137 knockout (KO) neuro2A cell line to analyze GPR137 function in neuronal cells. KO cells were generated by genome editing using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and cultured as single cells by limited dilution. Rescue cells were then constructed to re-express GPR137 in GPR137 KO neuro2A cells using an expression vector with an EF1-alpha promoter. GPR137 KO cells increased cellular proliferation and decreased neurite outgrowth (i.e., a lower level of neuronal differentiation). Furthermore, GPR137 KO cells exhibited increased expression of a cell cycle regulator, cyclin D1, and decreased expression of a neuronal differentiation marker, NeuroD1. Additionally, GPR137 KO cells exhibited lower expression levels of the neurite outgrowth markers STAT3 and GAP43. These phenotypes were all abrogated in the rescue cells. In conclusion, GPR137 deletion increased cellular proliferation and decreased neuronal differentiation, suggesting that GPR137 promotes cell cycle exit and neuronal differentiation in neuro2A cells. Regulation of neuronal differentiation by GPR137 could be vital to constructing neuronal structure during brain development.

Microglial depletion exacerbates axonal damage and motor dysfunction in mice with cuprizone-induced demyelination.

The cuprizone (CPZ)-induced demyelination model, an animal model of Multiple sclerosis (MS), is characterized by demyelination and motor dysfunction due to microglial-mediated neuroinflammation. To determine the contribution of microglia to motor function during CPZ-induced demyelination, the microglia of mice in the CPZ-model were depleted using PLX3397 (PLX), an orally bioavailable selective colony stimulating factor 1 receptor inhibitor. PLX treatment aggravated motor dysfunction as shown by the pole, beam walk, ladder walk, and rotarod tests. PLX treatment removed microglia from the superior cerebellar peduncle (SCP), but not from the corpus callosum (CC). Although PLX treatment did not affect the degree of demyelination in both of CC and SCP, the expression of axonal damage marker APP (amyloid precursor protein) was increased. Increased TNF-α, IL-1ß, and iNOS expressions were observed in PLX-treated mice. These results suggest that microglial depletion exacerbates axonal damage and motor dysfunction in CPZ model mice. In this study, we found that microglia contribute to motor function and axon-protective effects in CPZ-induced demyelination.

Testosterone interrupts binding of Neurexin and Neuroligin that are expressed in a highly socialized rodent, Octodon degus.

Octodon degus is said to be one of the most human-like rodents because of its improved cognitive function. Focusing on its high sociality, we cloned and characterized some sociality-related genes of degus, in order to establish degus as a highly socialized animal model in molecular biology. We cloned degus Neurexin and Neuroligin as sociality-related genes, which are genetically related to autism spectrum disorder in human. According to our results, amino acid sequences of Neurexin and Neuroligin expressed in degus brain, are highly conserved to that of human sequences. Most notably, degus Neuroligin4 is highly similar to human Neuroligin4X, which is one of the most important autism-related genes, whereas mouse Neuroligin4 is known to be poorly similar to human Neuroligin4X. Furthermore, our work also indicated that testosterone directly binds to degus Neurexin and intercepts intercellular Neurexin-Neuroligin binding. Moreover, it is of high interest that testosterone is another key molecule of the higher incidence of autism in male. These results indicated that degus has the potential for animal model of sociality, and furthermore may promote understanding toward the pathogenic mechanism of autism.

A peripheral lipid sensor GPR120 remotely contributes to suppression of PGD2-microglia-provoked neuroinflammation and neurodegeneration in the mouse hippocampus.

BACKGROUND: Neuroinflammation is a key pathological component of neurodegenerative disease and is characterized by microglial activation and the secretion of proinflammatory mediators. We previously reported that a surge in prostaglandin D2 (PGD2) production and PGD2-induced microglial activation could provoke neuroinflammation. We also reported that a lipid sensor GPR120 (free fatty acid receptor 4), which is expressed in intestine, could be activated by polyunsaturated fatty acids (PUFA), thereby mediating secretion of glucagon-like peptide-1 (GLP-1). Dysfunction of GPR120 results in obesity in both mice and humans. METHODS: To reveal the relationship between PGD2-microglia-provoked neuroinflammation and intestinal PUFA/GPR120 signaling, we investigated neuroinflammation and neuronal function with gene and protein expression, histological, and behavioral analysis in GPR120 knockout (KO) mice. RESULTS: In the current study, we discovered notable neuroinflammation (increased PGD2 production and microglial activation) and neurodegeneration (declines in neurogenesis, hippocampal volume, and cognitive function) in GPR120 KO mice. We also found that Hematopoietic-prostaglandin D synthase (H-PGDS) was expressed in microglia, microglia were activated by PGD2, H-PGDS expression was upregulated in GPR120 KO hippocampus, and inhibition of PGD2 production attenuated this neuroinflammation. GPR120 KO mice exhibited reduced intestinal, plasma, and intracerebral GLP-1 contents. Peripheral administration of a GLP-1 analogue, liraglutide, reduced PGD2-microglia-provoked neuroinflammation and further neurodegeneration in GPR120 KO mice. CONCLUSIONS: Our results suggest that neurological phenotypes in GPR120 KO mice are probably caused by dysfunction of intestinal GPR120. These observations raise the possibility that intestinal GLP-1 secretion, stimulated by intestinal GPR120, may remotely contributed to suppress PGD2-microglia-provoked neuroinflammation in the hippocampus.

Immunohistochemical characterization of granulomatosis with polyangiitis exhibiting spontaneous regression.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is characterized by granulomatous inflammation, vasculitis, and elevated levels of serum proteinase 3 (PR3)-anti-neutrophil cytoplasmic antibody (PR3-ANCA). OBJECTIVE: We tried to characterize immune cells accumulated into the lung lesions of a GPA patient exhibiting spontaneous regression. METHODS: Transbronchial lung biopsy (TBLB) samples were subjected to immunohistochemical analyses. RESULTS: Multiple lung nodules were detected by CT. TBLB showed granulomatous inflammation and small vessel vasculitis. This case was diagnosed as GPA based on pathological findings and elevation of PR-3 ANCA levels. Spontaneous disappearance of multiple lung nodules was observed in CT. CD3+ T cells and CD20+ B cells accumulated in the inflammatory lesions surrounding the vessels whereas granulomatous inflammation was mainly comprised of CD3+ T cells and CD68+ macrophages, but not B cells or myeloperoxidase+ neutrophils. CONCLUSIONS: We characterized immune cell compositions of the lung lesions of a patient with GPA exhibiting spontaneous regression.

Evaluation of the pharmacokinetics of 2-carba-cyclic phosphatidic acid by liquid chromatography-triple quadrupole mass spectrometry.

Cyclic phosphatidic acid (cPA) is a lysophospholipid mediator that suppresses cancer metastasis and osteoarthritis. It also has neuroprotective roles in diseases such as multiple sclerosis and delayed neuronal death following transient ischemia. In order to take advantage of the properties of cPA for the development of new therapeutic strategies, we have synthesized several cPA derivatives and discovered 2-carba-cPA (2ccPA) as a promising candidate. To develop 2ccPA as a therapeutic agent, we investigated the pharmacokinetic profile of 2ccPA by liquid chromatography-triple quadrupole mass spectrometry in this study. When 2ccPA was administered intraperitoneally to mice at a dose of 1.6 mg/kg, the half-life of 2ccPA in plasma was 16 min. The 2ccPA, dosed intraperitoneally to mice at 16 mg/kg, distributed to each organ including brain at 20 min after dosing. It was found that 2ccPA was stable in neutral or alkaline conditions (e.g., intestine) but unstable in acidic conditions (e.g., stomach). When 2ccPA was orally administrated to rats as a gastro-resistant form using an enterosoluble capsule, plasma 2ccPA levels peaked at 2 h, slowly declined thereafter and persistently detected even at 10 h after administration. Here, we present the findings on the effect of the continuous release of 2ccPA from the capsule to reduce the lysophospholipase D activity and also decrease plasma levels of lysophosphatidic acid in rat. These findings will be useful in further studies for evaluating the application of 2ccPA in several disorders.

Ursolic acid treatment suppresses cuprizone-induced demyelination and motor dysfunction via upregulation of IGF-1.

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system, characterized by apoptotic death of mature oligodendrocytes, neuroinflammation, and motor dysfunction. A pentacyclic triterpenoid compound, ursolic acid (UA), has various pharmacological activities, such as anti-inflammatory, anti-oxidative, and anti-apoptotic effects. In the present study, we investigated the effects of UA on cuprizone-induced demyelination, which is a model of MS. Oral administration of UA effectively suppressed cuprizone-induced demyelination and motor dysfunction via the enhancement of IGF-1 levels in the demyelinating lesions. Our results suggest that UA might be therapeutically useful for demyelination in MS.

Correction to: Protective and therapeutic role of 2-carbacyclic phosphatidic acid in demyelinating disease.

After publication of the article [1], it was brought to our attention that an acknowledgement was missing from the original version.

ELectron microscopic abnormality and therapeutic efficacy in chronic inflammatory demyelinating polyneuropathy with anti-neurofascin155 immunoglobulin G4 antibody.

INTRODUCTION: Neurofascin155 (NF155) is a target antigen for autoantibodies in a subset of chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: We report the cases of 4 patients with anti-NF155 immunoglobulin G4 (IgG4) antibody-positive CIDP who underwent sural nerve biopsies. RESULTS: All patients were relatively young at onset. Three patients experienced tremors, and 2 patients had severe ataxia. Although the response to intravenous immunoglobulin was poor in all patients, plasma exchange and corticosteroids were at least partially effective. Immunoadsorption plasmapheresis was performed in 1 patient but was ineffective. Electron microscopic examination of sural nerve biopsies revealed loss of paranodal transverse bands in all patients. DISCUSSION: Anti-NF155 IgG4 antibody-positive CIDP shows distinctive clinicopathological features, indicating that the IgG4 antibody is directly associated with the pathogenic mechanisms of anti-NF155 IgG4 antibody-positive CIDP. Muscle Nerve 57: 498-502, 2018.

LPA5 signaling is involved in multiple sclerosis-mediated neuropathic pain in the cuprizone mouse model.

Lysophosphatidic acid (LPA) and LPA1 receptor signaling play a crucial role in the initiation of peripheral nerve injury-induced neuropathic pain through the alternation of pain-related genes/proteins expression and demyelination. However, LPA and its signaling in the brain are still poorly understood. In the present study, we revealed that the LPA5 receptor expression in corpus callosum elevated after the initiation of demyelination, and the hyperalgesia through Aδ-fibers following cuprizone-induced demyelination was mediated by LPA5 signaling. These data suggest that LPA5 signaling may play a key role in the mechanisms underlying neuropathic pain following demyelination in the brain.

Excitotoxicity-induced prostaglandin D2 production induces sustained microglial activation and delayed neuronal death.

Excitotoxicity is the pivotal mechanism of neuronal death. Prostaglandins (PGs) produced during excitotoxicity play important roles in neurodegenerative conditions. Previously, we demonstrated that initial burst productions of PGD2, PGE2, and PGF2α are produced by cyclooxygenase-2 (COX-2) in the hippocampus following a single systemic kainic acid (KA) administration. In addition, we showed that blocking of all PG productions ameliorated hippocampal delayed neuronal death at 30 days after KA administration. To investigate the role of individual PGs in the delayed neuronal death, we performed intracerebroventricular injection of PGD2, PGE2, or PGF2α in rats whose hippocampal PG productions were entirely blocked by pretreatment of NS398, a COX-2 selective inhibitor. Administration of PGD2 and PGF2α had a latent contribution to the delayed neuronal death, sustained over 30 days after a single KA treatment. Furthermore, PGD2 enhanced microglial activation, which may be involved in the delayed neuronal death in the hippocampus. These findings suggest that excitotoxic delayed neuronal death is mediated through microglia activated by PGD2.

Protective and therapeutic role of 2-carba-cyclic phosphatidic acid in demyelinating disease.

BACKGROUND: Multiple sclerosis is a neuroinflammatory demyelinating and neurodegenerative disease of the central nervous system characterized by recurrent and progressive demyelination/remyelination cycles, neuroinflammation, oligodendrocyte loss, demyelination, and axonal degeneration. Cyclic phosphatidic acid (cPA) is a natural phospholipid mediator with a unique cyclic phosphate ring structure at the sn-2 and sn-3 positions of the glycerol backbone. We reported earlier that cPA elicits a neurotrophin-like action and protects hippocampal neurons from ischemia-induced delayed neuronal death. We designed, chemically synthesized, and metabolically stabilized derivatives of cPA: 2-carba-cPA (2ccPA), a synthesized compound in which one of the phosphate oxygen molecules is replaced with a methylene group at the sn-2 position. In the present study, we investigated whether 2ccPA exerts protective effects in oligodendrocytes and suppresses pathology in the two most common mouse models of multiple sclerosis. METHODS: To evaluate whether 2ccPA has potential beneficial effects on the pathology of multiple sclerosis, we investigated the effects of 2ccPA on oligodendrocyte cell death in vitro and administrated 2ccPA to mouse models of experimental autoimmune encephalomyelitis (EAE) and cuprizone-induced demyelination. RESULTS: We demonstrated that 2ccPA suppressed the CoCl2-induced increase in the Bax/Bcl-2 protein expression ratio and phosphorylation levels of p38MAPK and JNK protein. 2ccPA treatment reduced cuprizone-induced demyelination, microglial activation, NLRP3 inflammasome, and motor dysfunction. Furthermore, 2ccPA treatment reduced autoreactive T cells and macrophages, spinal cord injury, and pathological scores in EAE, the autoimmune multiple sclerosis mouse model. CONCLUSIONS: We demonstrated that 2ccPA protected oligodendrocytes via suppression of the mitochondrial apoptosis pathway. Also, we found beneficial effects of 2ccPA in the multiperiod of cuprizone-induced demyelination and the pathology of EAE. These data indicate that 2ccPA may be a promising compound for the development of new drugs to treat demyelinating disease and ameliorate the symptoms of multiple sclerosis.

Determination of volatile compounds in four commercial samples of Japanese green algae using solid phase microextraction gas chromatography mass spectrometry.

Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Origin of O2 Generation in Sulfide-Based All-Solid-State Batteries and its Impact on High Energy Density.

The cathode surface of sulfide-based all-solid-state batteries (SBs) is commonly coated with amorphous-LiNbO3 in order to stabilize charge-discharge reactions. However, high-voltage charging diminishes the advantages, which is caused by problems with the amorphous-LiNbO3 coating layer. This study has investigated the degradation of amorphous-LiNbO3 coating layer directly during the high-voltage charging of SBs. O2 generation via Li extraction from the amorphous-LiNbO3 coating layer is observed using electrochemical gas analysis and electrochemical X-ray photoelectron spectroscopy. This O2 leads to the formation of an oxidative solid electrolyte (SE) around the coating layer and degrades the battery performance. On the other hand, elemental substitution (i.e., amorphous-LiNbxP1- xO3) reduces O2 release, leading to stable high-voltage charge-discharge reactions of SBs. The results have emphasized that the suppression of O2 generation is a key factor in improving the energy density of SBs.

Takotsubo cardiomyopathy in Guillain-Barré syndrome.

BACKGROUND AND PURPOSE: Takotsubo cardiomyopathy (TCM) is a serious autonomic complication of Guillain-Barré syndrome (GBS). However, the association between TCM and GBS has not been investigated in detail. We investigated the characteristics of GBS patients with TCM (GBS-TCM). METHODS: Clinical features and anti-ganglioside antibody between the GBS-TCM patients and 62 classical GBS patients without TCM as control patients were compared. RESULTS: Eight GBS-TCM patients were identified, in whom TCM was diagnosed at a mean of 6.5 [range 3-42] days after the onset of GBS. The age at onset of GBS was elder in the GBS-TCM patients than in the control GBS patients (76.5 [56-87] vs. 52 [20-88] years, p < 0.01). Notably, cranial nerve deficits, particularly in the lower cranial nerves, were observed in all GBS-TCM patients (100% vs. 41.9%, p < 0.01). Additionally, the GBS-TCM patients showed a higher GBS disability score at nadir (5 [4-5] vs. 4 [1-5], p < 0.01), and lower Medical Research Council sum scores at admission and nadir (37 [30-44] vs. 48 [12-60] at admission, p < 0.05, and 20 [12-44] vs. 40 [0-60] at nadir, p < 0.05, respectively). Mechanical ventilation was more frequently required in the GBS-TCM patients (62.5% vs. 11.3%, p < 0.01). Three GBS-TCM patients were positive for anti-ganglioside antibodies. CONCLUSIONS: TCM occurred at a relatively early phase of GBS. The characteristics of GBS-TCM were the elder, lower cranial nerve involvements, severe limb weakness, and respiratory failure.

Characteristics of Guillain-Barré syndrome in super-elderly individuals.

BACKGROUND: Japan has the world's largest super-aging population, and the number of elderly patients with various diseases is increasing. Herein, we reported the characteristics of super-elderly patients, aged over 80 years, with Guillain-Barré syndrome (GBS), a typical neuroimmune disease. METHODS: During the period 2019-2021, 74 patients over the age of 80 years diagnosed with GBS at Kindai university were analyzed as the super-elderly group patients. The control group comprised 74 consecutive patients aged < 79 years, under the same conditions. GBS was diagnosed using Brighton diagnostic criteria. Electrophysiology was assessed using the Ho criteria. RESULTS: The mean age was 83.5 years in the super-elderly group and 51.7 years in the control group. Prior infection was recognized in 50% of cases in the super-elderly group and 77% of cases in the control group with fewer cases in the super-elderly group. The mean number of days until peak symptom presentation was longer in the super-elderly group. The percentage who required a ventilator was significantly higher among the super-elderly group than among the control group. Hughes functional grading scale was more severe in the super-elderly group. Electrophysiological examination revealed the demyelinating form was particularly common in the super-elderly group. Intravenous immunoglobulin was the most common treatment in both the groups, with no difference in efficacy. CONCLUSIONS: Super-elderly onset GBS tends to be severe, therefore it is important to diagnose and treat appropriately, even in the absence of prior episodes of infection.

A case of thymoma-associated myasthenia gravis accompanied with myositis showing the clusters of histiocyte along the fascicles in perimysium.

Patients with myasthenia gravis (MG) often have other autoimmune disorders. However, the coexistence of MG and myositis is rare. Here, we report a case of a 77-year-old woman who developed mild fatigable muscle weakness and diplopia in 3 months. Serum creatine kinase was elevated to 1385 IU/L. Antibodies to acetylcholine receptor (AChR), titin and voltage-gated potassium channel 1.4 (Kv 1.4) were all positive while all tested myositis-specific autoantibodies were negative. Standard needle electromyography showed fibrillation potential and early recruitment of motor units. The repetitive nerve stimulations were consistent with a disorder of the neuromuscular junction. Muscle biopsy showed that the clusters of histiocyte were present along the fascicles in perimysium and some of them invaded into endomysium.

Memantine administration prevented chorea movement in Huntington's disease: a case report.

BACKGROUND: Huntington's disease is an autosomal dominant inherited disorder characterized by personality changes (such as irritability and restlessness) and psychotic symptoms (such as hallucinations and delusions). When the personality changes become noticeable, involuntary movements (chorea) also develop. The disease is caused by the CAG repeat expansion in the coding region of the HTT gene, and the diagnosis is based on the presence of this expansion. However, there is currently no effective treatment for the progression of Huntington's disease and its involuntary motor symptoms. Herein, we present a case in which memantine was effective in treating the chorea movements of Huntington's disease. CASE PRESENTATION: A 75-year-old Japanese woman presented to the hospital with involuntary movements of Huntington's disease that began when she was 73 years old. In a cerebral blood flow test (N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography), decreased blood flow was observed in the precuneus (anterior wedge) and posterior cingulate gyrus. Usually, such areas of decreased blood flow are observed in patients with Alzheimer's-type dementia. So, we administered memantine for Alzheimer's-type dementia, and this treatment suppressed the involuntary movements of Huntington's disease, and the symptoms progressed slowly for 7 years after the onset of senility. In contrast, her brother died of complications of pneumonia during the course of Huntington's disease. CONCLUSIONS: We recorded changes in parameters such as the results of the N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography and gait videos over 7 years. Treatment with memantine prevented the chorea movement and the progression of Huntington's disease. We believe this record will provide clinicians with valuable information in diagnosing and treating Huntington's disease.

Long term administration of loquat leaves and their major component, ursolic acid, attenuated endogenous amyloid-ß burden and memory impairment.

Loquat (Eriobotrya japonica) leaves contain many bioactive components such as ursolic acid (UA) and amygdalin. We investigated the effects of loquat leaf powder and methanol extract in human neuroglioma H4 cells stably expressing the Swedish-type APP695 (APPNL-H4 cells) and C57BL/6 J mice. Surprisingly, the extract greatly enhanced cellular amyloid-beta peptide (Aß) 42 productions in APPNL-H4 cells. Administration of leaf powder increased Aß42 levels after 3 months and decreased levels after 12 months compared to control mice. Leaf powder had no effect on working memory after 3 months, but improved working memory after 12 months. Administration of UA decreased Aß42 and P-tau levels and improved working memory after 12 months, similar to the administration of leave powder for 12 months. Amygdalin enhanced cellular Aß42 production in APPNL-H4 cells, which was the same as the extract. Three-month administration of amygdalin increased Aß42 levels slightly but did not significantly increase them, which is similar to the trend observed with the administration of leaf powder for 3 months. UA was likely the main compound contained in loquat leaves responsible for the decrease in intracerebral Aß42 and P-tau levels. Also, amygdalin might be one of the compounds responsible for the transiently increased intracerebral Aß42 levels.