Dimethyl fumarate improves cognitive impairment and neuroinflammation in mice with Alzheimer's disease

BACKGROUND

Neuroinflammation substantially contributes to the pathology of Alzheimer's disease (AD), the most common form of dementia. Studies have reported that nuclear factor erythroid 2-related factor 2 (Nrf2) attenuates neuroinflammation in the mouse models of neurodegenerative diseases, however, the detailed mechanism remains unclear.

METHODS

The effects of dimethyl fumarate (DMF), a clinically used drug to activate the Nrf2 pathway, on neuroinflammation were analyzed in primary astrocytes and AppNL-G-F (App-KI) mice. The cognitive function and behavior of DMF-administrated App-KI mice were evaluated. For the gene expression analysis, microglia and astrocytes were directly isolated from the mouse cerebral cortex by magnetic-activated cell sorting, followed by quantitative PCR.

RESULTS

DMF treatment activated some Nrf2 target genes and inhibited the expression of proinflammatory markers in primary astrocytes. Moreover, chronic oral administration of DMF attenuated neuroinflammation, particularly in astrocytes, and reversed cognitive dysfunction presumably by activating the Nrf2-dependent pathway in App-KI mice. Furthermore, DMF administration inhibited the expression of STAT3/C3 and C3 receptor in astrocytes and microglia isolated from App-KI mice, respectively, suggesting that the astrocyte-microglia crosstalk is involved in neuroinflammation in mice with AD.

CONCLUSION

The activation of astrocytic Nrf2 signaling confers neuroprotection in mice with AD by controlling neuroinflammation, particularly by regulating astrocytic C3-STAT3 signaling. Furthermore, our study has implications for the repositioning of DMF as a drug for AD treatment.

Genetic background variation impacts microglial heterogeneity and disease progression in amyotrophic lateral sclerosis model mice

Recent single-cell analyses have revealed the complexity of microglial heterogeneity in brain development, aging, and neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). Disease-associated microglia (DAMs) have been identified in ALS mice model, but their role in ALS pathology remains unclear. The effect of genetic background variations on microglial heterogeneity and functions remains unknown. Herein, we established and analyzed two mice models of ALS with distinct genetic backgrounds of C57BL/6 and BALB/c. We observed that the change in genetic background from C57BL/6 to BALB/c affected microglial heterogeneity and ALS pathology and its progression, likely due to the defective induction of neurotrophic factor-secreting DAMs and impaired microglial survival. Single-cell analyses of ALS mice revealed new markers for each microglial subtype and a possible association between microglial heterogeneity and systemic immune environments. Thus, we highlighted the role of microglia in ALS pathology and importance of genetic background variations in modulating microglial functions.

Novel insights into brain lipid metabolism in Alzheimer's disease: Oligodendrocytes and white matter abnormalities

Alzheimer's disease (AD) is the most common cause of dementia. A genome-wide association study has shown that several AD risk genes are involved in lipid metabolism. Additionally, epidemiological studies have indicated that the levels of several lipid species are altered in the AD brain. Therefore, lipid metabolism is likely changed in the AD brain, and these alterations might be associated with an exacerbation of AD pathology. Oligodendrocytes are glial cells that produce the myelin sheath, which is a lipid-rich insulator. Dysfunctions of the myelin sheath have been linked to white matter abnormalities observed in the AD brain. Here, we review the lipid composition and metabolism in the brain and myelin and the association between lipidic alterations and AD pathology. We also present the abnormalities in oligodendrocyte lineage cells and white matter observed in AD. Additionally, we discuss metabolic disorders, including obesity, as AD risk factors and the effects of obesity and dietary intake of lipids on the brain.

An open chat with… Koji Yamanaka

Koji Yamanaka is a Professor at the Research Institute of Environmental Medicine at Nagoya University of Japan. His research interests lie in understanding the mechanism of onset and progression of motor neuron disease as well as the role of glial cells in Alzheimer's disease neuroinflammation. Koji has been serving on the FEBS Open Bio Editorial Board since 2013. In this interview, he explains the implications of recent findings in neurobiology for amyotrophic lateral sclerosis, provides updates on the research environment in Japan and discusses how editors might use their position to positively influence academic culture.

Mitochondria-associated membrane collapse impairs TBK1-mediated proteostatic stress response in ALS

The organelle contact site of the endoplasmic reticulum and mitochondria, known as the mitochondria-associated membrane (MAM), is a multifunctional microdomain in cellular homeostasis. We previously reported that MAM disruption is a common pathological feature in amyotrophic lateral sclerosis (ALS); however, the precise role of MAM in ALS was uncovered. Here, we show that the MAM is essential for TANK-binding kinase 1 (TBK1) activation under proteostatic stress conditions. A MAM-specific E3 ubiquitin ligase, autocrine motility factor receptor, ubiquitinated nascent proteins to activate TBK1 at the MAM, which results in ribosomal protein degradation. MAM or TBK1 deficiency under proteostatic stress conditions resulted in increased cellular vulnerability in vitro and motor impairment in vivo. Thus, MAM disruption exacerbates proteostatic stress via TBK1 inactivation in ALS. Our study has revealed a proteostatic mechanism mediated by the MAM-TBK1 axis, highlighting the physiological importance of the organelle contact sites.

The necessity to improve disaster preparedness among patients with amyotrophic lateral sclerosis and their families

Disaster preparation is an important issue for patients with amyotrophic lateral sclerosis (ALS). However, to the best of our knowledge, no studies have investigated disaster preparedness among patients with ALS. In this study, we aimed to investigate disaster preparation in patients with ALS and their caregivers, including their families, in Japan. We conducted a nationwide webinar in September 2022 titled "ALS Café" and distributed a self-report questionnaire to participants with questions about awareness of disaster preparedness, social countermeasures, stockpiles, and electricity demand. Forty-eight patients with ALS (27 male; average age 60.0 ± 9.3 years) and 23 caregivers (8 male; 55.7 ± 9.9 years) responded. The median revised ALS Functional Rating Scale score was 30.5, and 25% of the patients with ALS were on a ventilator. More than 70% of the respondents answered that they were not prepared for disasters, increasing to 89% in patients not using ventilators. In the event of their phones being down, 86% of the respondents had no plans for alternative means of communication. <30% of the respondents, including ventilator users, had secured human resources for transportation. Twenty-five percent of the respondents did not stockpile food and beverages, and 12% of the ventilator users had no government-recommended ventilator preparation equipment. Thus, although patients with ALS and their families with ventilators have a high awareness of disaster preparedness, their awareness remains insufficient. Furthermore, patients with ALS and their families without ventilators have a low awareness of disaster preparedness. Therefore, better education regarding disaster preparedness is necessary for these groups.

Investigation of non-motor symptoms in patients with amyotrophic lateral sclerosis

[Objective] Few studies have comprehensively investigated the non-motor symptoms of amyotrophic lateral sclerosis (ALS). We aimed to investigate this aspect of ALS. [Methods] We held a nationwide webinar, titled "ALS Café," and distributed self-report questionnaires to ALS patients. In addition to the frequency of non-motor symptoms such as fatigue, pain, sleep disorders, defecation disorders, sialorrhea, and sexual problems, we evaluated the quality of life (QoL), ALS Functional Rating Scale-Revised (ALSFRS-R), and Patient Health Questionnaire-9 (PHQ-9). [Results] The average age of the 33 respondents (19 male, 14 female) was 60.8 ± 11.2; 96.7% of respondents had some non-motor symptoms. The median ALSFRS-R was 32.0, and seven (21.2%) of the respondents had a PHQ-9 score of 10 or higher. Fatigue was the most common non-motor symptom (81.8%), followed by pain (60.6%), defecation disorders (57.6%), sleep disorders (48.5%), sialorrhea (48.5%), and sexual problems (24.2%). Fatigue was more frequent in females (P = 0.03). Among the non-motor symptoms, pain was the most common factor affecting QoL, followed by fatigue. More than 90% of ALS patients answered that they had never consulted a physician/counselor about sexual problems. Patients with pain had higher PHQ-9 scores than those without (P = 0.01). There was no correlation between the ALSFRS-R score and QoL and PHQ-9. [Conclusions] Most patients with amyotrophic lateral sclerosis had non-motor symptoms, and fatigue and pain were the most common. We showed that many non-motor symptoms affected QoL without correlating with ALSFRS-R score. Attention should be paid to those even if the motor symptoms of ALS are mild.

Monomerization of TDP-43 is a key determinant for inducing TDP-43 pathology in amyotrophic lateral sclerosis

The cytoplasmic aggregation of TAR DNA binding protein-43 (TDP-43), also known as TDP-43 pathology, is the pathological hallmark of amyotrophic lateral sclerosis (ALS). However, the mechanism underlying TDP-43 cytoplasmic mislocalization and subsequent aggregation remains unclear. Here, we show that TDP-43 dimerization/multimerization is impaired in the postmortem brains and spinal cords of patients with sporadic ALS and that N-terminal dimerization-deficient TDP-43 consists of pathological inclusion bodies in ALS motor neurons. Expression of N-terminal dimerization-deficient mutant TDP-43 in Neuro2a cells and induced pluripotent stem cell-derived motor neurons recapitulates TDP-43 pathology, such as Nxf1-dependent cytoplasmic mislocalization and aggregate formation, which induces seeding effects. Furthermore, TDP-DiLuc, a bimolecular luminescence complementation reporter assay, could detect decreased N-terminal dimerization of TDP-43 before TDP-43 pathological changes caused by the transcription inhibition linked to aberrant RNA metabolism in ALS. These findings identified TDP-43 monomerization as a critical determinant inducing TDP-43 pathology in ALS.

Cellular senescence in white matter microglia is induced during ageing in mice and exacerbates the neuroinflammatory phenotype

Cellular senescence, a state of irreversible cell-cycle arrest caused by a variety of cellular stresses, is critically involved in age-related tissue dysfunction in various organs. However, the features of cells in the central nervous system that undergo senescence and their role in neural impairment are not well understood as yet. Here, through comprehensive investigations utilising single-cell transcriptome analysis and various mouse models, we show that microglia, particularly in the white matter, undergo cellular senescence in the brain and spinal cord during ageing and in disease models involving demyelination. Microglial senescence is predominantly detected in disease-associated microglia, which appear in ageing and neurodegenerative diseases. We also find that commensal bacteria promote the accumulation of senescent microglia and disease-associated microglia during ageing. Furthermore, knockout of p16INK4a, a key senescence inducer, ameliorates the neuroinflammatory phenotype in damaged spinal cords in mice. These results advance our understanding of the role of cellular senescence in the central nervous system and open up possibilities for the treatment of age-related neural disorders.

Neuroinflammation in Alzheimer's disease: microglial signature and their relevance to disease

Alzheimer's disease (AD) is the most common form of dementia, pathologically characterized by senile plaques and neurofibrillary tangles (NFTs), resulting in neurodegeneration. Neuroinflammation, defined as the activation of glial cells such as microglia and astrocytes, is observed surrounding senile plaques and affected neurons in AD. Recently conducted genome-wide association studies (GWAS) indicate that a large section of identified AD risk genes are involved in immune responses and are enriched in microglia. Microglia are innate immune cells in the central nervous system (CNS), which are involved in immune surveillance and maintenance of homeostasis in the CNS. Recently, a novel subpopulation of activated microglia named as disease-associated microglia (DAM), also known as activated response microglia (ARM) or microglial neurodegenerative phenotype (MGnD), was identified in AD model mice. These microglia closely associate with β-amyloid (Aβ) plaques and exhibit characteristic gene expression profiles accompanied with reduced expressions of homeostatic microglial genes. However, it remains unclear whether decreased homeostatic microglia functions or increased DAM/ARM/MGnD functions correlate with the degree of neuronal loss in AD. To translate the results of rodent studies to human AD, precuneus, the brain region vulnerable to β-amyloid accumulation in preclinical AD, is of high interest, as it can provide novel insights into the mechanisms of microglia response to Aβ in early AD. In this study, we performed comparative analyses of gene expression profiles of microglia among three representative neurodegenerative mouse models and the human precunei with early AD pathology. We proceeded to evaluate the identified genes as potential therapeutic targets for AD. We believe that our findings will provide important resources to better understand the role of glial dysfunction in AD.

Intrinsic structural vulnerability in the hydrophobic core induces species-specific aggregation of canine SOD1 with degenerative myelopathy-linked E40K mutation

Canine degenerative myelopathy (DM), a fatal neurodegenerative disease in dogs, shares clinical and genetic features with amyotrophic lateral sclerosis (ALS), a human motor neuron disease. Mutations in the SOD1 gene encoding Cu/Zn superoxide dismutase (SOD1) cause canine DM and a subset of inherited human ALS. The most frequent DM causative mutation is homozygous E40K mutation which induces the aggregation of canine SOD1 but not of human SOD1. However, the mechanism through which canine E40K mutation induces species-specific aggregation of SOD1 remains unknown. By screening human/canine chimeric SOD1s, we identified that the humanized mutation of the 117th residue (M117L), encoded by exon 4, significantly reduced aggregation propensity of canine SOD1^E40K. Conversely, introducing a mutation of leucine 117 to methionine, a residue homologous to canine, promoted E40K-dependent aggregation in human SOD1. M117L mutation improved protein stability and reduced cytotoxicity of canine SOD1^E40K. Furthermore, crystal structural analysis of canine SOD1 proteins revealed that M117L increased the packing within the hydrophobic core of the β-barrel structure, contributing to the increased protein stability. Our findings indicate that the structural vulnerability derived intrinsically from Met 117 in the hydrophobic core of the β-barrel structure induces E40K-dependent species-specific aggregation in canine SOD1.

Sigma-1 receptor maintains ATAD3A as a monomer to inhibit mitochondrial fragmentation at the mitochondria-associated membrane in amyotrophic lateral sclerosis

Organelle contact sites are multifunctional platforms for maintaining cellular homeostasis. Alternations of the mitochondria-associated membranes (MAM), one of the organelle contact sites where the endoplasmic reticulum (ER) is tethered to the mitochondria, have been involved in the pathogenesis of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). However, the detailed mechanisms through which MAM integrity is disrupted in ALS have not been fully elucidated. Here, we examined whether AAA ATPase domain-containing protein 3A (ATAD3A), a mitochondrial membrane AAA ATPase accumulating at the MAM, is involved in ALS. We found that sigma-1 receptor (σ1R), an ER-resident MAM protein causative for inherited juvenile ALS, required ATAD3A to maintain the MAM. In addition, σ1R retained ATAD3A as a monomer, which is associated with an inhibition of mitochondrial fragmentation. ATAD3A dimerization and mitochondrial fragmentation were significantly induced in σ1R-deficient or SOD1-linked ALS mouse spinal cords. Overall, these observations indicate that MAM induction by σ1R depends on ATAD3A and that σ1R maintains ATAD3A as a monomer to inhibit mitochondrial fragmentation. Our findings suggest that targeting σ1R-ATAD3A axis would be promising for a novel therapeutic strategy to treat mitochondrial dysfunction in neurological disorders, including ALS.

Corrigendum: Comprehensive expression analysis with cell-type-specific transcriptome in ALS-linked mutant SOD1 mice: Revisiting the active role of glial cells in disease

[This corrects the article DOI: 10.3389/fncel.2022.1045647.].

Comprehensive expression analysis with cell-type-specific transcriptome in ALS-linked mutant SOD1 mice: Revisiting the active role of glial cells in disease

Non-cell autonomous mechanisms are involved in the pathogenesis of amyotrophic lateral sclerosis (ALS), an adult neurodegenerative disease characterized by selective motor neuron loss. While the emerging role of glial cells in ALS has been noted, the detailed cell-type-specific role of glial cells has not been clarified. Here, we examined mRNA expression changes using microarrays of the spinal cords of three distinct lines of mutant superoxide dismutase (SOD) 1 transgenic mice, an established ALS model. Our analysis used a transcriptome database of component cell types in the central nervous system (CNS), as well as SOD1 ^G93A cell-type transcriptomes. More than half of the differentially expressed genes (DEGs) were highly expressed in microglia, and enrichment analysis of DEGs revealed that immunological reactions were profoundly involved and some transcription factors were upregulated. Our analysis focused on DEGs that are highly expressed in each cell type, as well as chemokines, caspases, and heat shock proteins. Disease-associated microglial genes were upregulated, while homeostatic microglial genes were not, and galectin-3 (Mac2), a known activated microglial marker, was predicted to be ectopically expressed in astrocytes in mutant SOD1 mice. In mutant SOD1 mice, we developed a prediction model for the pathophysiology of different cell types related to TREM2, apolipoprotein E, and lipoproteins. Our analysis offers a viable resource to understand not only the molecular pathologies of each CNS constituent cell type, but also the cellular crosstalk between different cell types under both physiological and pathological conditions in model mice for various neurodegenerative diseases.

Novel reporters of mitochondria-associated membranes (MAM), MAMtrackers, demonstrate MAM disruption as a common pathological feature in amyotrophic lateral sclerosis

The mitochondria-associated membrane (MAM) is a functional subdomain of the endoplasmic reticulum membrane that tethers to the mitochondrial outer membrane and is essential for cellular homeostasis. A defect in MAM is involved in various neurological diseases, including amyotrophic lateral sclerosis (ALS). Recently, we and others reported that MAM was disrupted in the models expressing several ALS-linked genes, including SOD1, SIGMAR1, VAPB, TARDBP, and FUS, suggesting that MAM disruption is deeply involved in the pathomechanism of ALS. However, it is still uncertain whether MAM disruption is a common pathology in ALS, mainly due to the absence of a simple, quantitative tool for monitoring the status of MAM. In this study, to examine the effects of various ALS-causative genes on MAM, we created the following two novel MAM reporters: MAMtracker-Luc and MAMtracker-Green. The MAMtrackers could detect MAM disruption caused by suppression of SIGMAR1 or the overexpression of ALS-linked mutant SOD1 in living cells. Moreover, the MAMtrackers have an advantage in their ability to monitor reversible changes in the MAM status induced by nutritional conditions. We used the MAMtrackers with an expression plasmid library of ALS-causative genes and noted that 76% (16/21) of the genes altered MAM integrity. Our results suggest that MAM disruption is a common pathological feature in ALS. Furthermore, we anticipate our MAMtrackers, which are suitable for high-throughput assays, to be valuable tools to understand MAM dynamics.

Microglial gene signature reveals loss of homeostatic microglia associated with neurodegeneration of Alzheimer's disease

Microglia-mediated neuroinflammation has been implicated in the pathogenesis of Alzheimer’s disease (AD). Although microglia in aging and neurodegenerative disease model mice show a loss of homeostatic phenotype and activation of disease-associated microglia (DAM), a correlation between those phenotypes and the degree of neuronal cell loss has not been clarified. In this study, we performed RNA sequencing of microglia isolated from three representative neurodegenerative mouse models, App^{NL-G-F/NL-G-F} with amyloid pathology, rTg4510 with tauopathy, and SOD1^G93A with motor neuron disease by magnetic activated cell sorting. In parallel, gene expression patterns of the human precuneus with early Alzheimer’s change (n = 11) and control brain (n = 14) were also analyzed by RNA sequencing. We found that a substantial reduction of homeostatic microglial genes in rTg4510 and SOD1^G93A microglia, whereas DAM genes were uniformly upregulated in all mouse models. The reduction of homeostatic microglial genes was correlated with the degree of neuronal cell loss. In human precuneus with early AD pathology, reduced expression of genes related to microglia- and oligodendrocyte-specific markers was observed, although the expression of DAM genes was not upregulated. Our results implicate a loss of homeostatic microglial function in the progression of AD and other neurodegenerative diseases. Moreover, analyses of human precuneus also suggest loss of microglia and oligodendrocyte functions induced by early amyloid pathology in human.

Stagnation of glymphatic interstitial fluid flow and delay in waste clearance in the SOD1-G93A mouse model of ALS

Overexpression and mislocalization of aquaporin-4 (AQP4) in the SOD1^G93A mouse model of amyotrophic lateral sclerosis (ALS) have previously been reported. However, how alterations of AQP4 affect interstitial bulk flow in the brain and spinal cord, the so-called glymphatic system, is unclear. Here, we report an enhanced accumulation of disease-associated SOD1 species including SOD1 oligomers in SOD1^G93A;AQP4^-/- mice compared with SOD1^G93A mice during ALS disease progression, as analyzed by sandwich ELISA. By directly injecting SOD1 oligomers into the spinal cord parenchyma, we observed a significantly larger delay in clearance of biotinylated or fluorescent-labeled SOD1 oligomers in AQP4^-/- mice than in wild-type mice. Furthermore, when we injected the fluorescent-labeled tracer protein ovalbumin into the cisterna magna and analyzed the tracer distribution in the cervical spinal cord, approximately 35 % processing ability was found to be reduced in SOD1^G93A mice compared to wild-type mice. These results suggest that the glymphatic system is abnormal and that waste clearance is delayed in SOD1^G93A mice.

Touchscreen-based location discrimination and paired associate learning tasks detect cognitive impairment at an early stage in an App knock-in mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline with accumulation of amyloid beta (Aβ) and neurofibrillary tangles that usually begins 15–30 years before clinical diagnosis. Rodent models that recapitulate aggressive Aβ and/or the pathology of neurofibrillary tangles are essential for AD research. Accordingly, non-invasive early detection systems in these animal models are required to evaluate the phenotypic changes, elucidate the mechanism of disease progression, and facilitate development of novel therapeutic approaches. Although many behavioral tests efficiently reveal cognitive impairments at the later stage of the disease in AD models, it has been challenging to detect such impairments at the early stage. To address this issue, we subjected 4–6-month-old male App^{NL−G−F/NL−G−F} knock-in (App-KI) mice to touchscreen-based location discrimination (LD), different object–location paired-associate learning (dPAL), and reversal learning tests, and compared the results with those of the classical Morris water maze test. These tests are mainly dependent on the brain regions prone to Aβ accumulation at the earliest stages of the disease. At 4–6 months, considered to represent the early stage of disease when mice exhibit initial deposition of Aβ and slight gliosis, the classical Morris water maze test revealed no difference between groups, whereas touchscreen-based LD and dPAL tasks revealed significant impairments in task performance. Our report is the first to confirm that a systematic touchscreen-based behavioral test battery can sensitively detect the early stage of cognitive decline in an AD-linked App-KI mouse model. This system could be applied in future translational research.

Astrocytic phagocytosis is a compensatory mechanism for microglial dysfunction

Microglia are the principal phagocytes that clear cell debris in the central nervous system (CNS). This raises the question, which cells remove cell debris when microglial phagocytic activity is impaired. We addressed this question using Siglech^dtr mice, which enable highly specific ablation of microglia. Non‐microglial mononuclear phagocytes, such as CNS‐associated macrophages and circulating inflammatory monocytes, did not clear microglial debris. Instead, astrocytes were activated, exhibited a pro‐inflammatory gene expression profile, and extended their processes to engulf microglial debris. This astrocytic phagocytosis was also observed in Irf8‐deficient mice, in which microglia were present but dysfunctional. RNA‐seq demonstrated that even in a healthy CNS, astrocytes express TAM phagocytic receptors, which were the main astrocytic phagocytic receptors for cell debris in the above experiments, indicating that astrocytes stand by in case of microglial impairment. This compensatory mechanism may be important for the maintenance or prolongation of a healthy CNS.

Novel Selenium-based compounds with therapeutic potential for SOD1-linked amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease as well as Lou Gehrig's disease, is a progressive neurological disorder selectively affecting motor neurons with no currently known cure. Around 20% of the familial ALS cases arise from dominant mutations in the sod1 gene encoding superoxide dismutase1 (SOD1) enzyme. Aggregation of mutant SOD1 in familial cases and of wild-type SOD1 in at least some sporadic ALS cases is one of the known causes of the disease. Riluzole, approved in 1995 and edaravone in 2017 remain the only drugs with limited therapeutic benefits.

Methods

We have utilised the ebselen template to develop novel compounds that redeem stability of mutant SOD1 dimer and prevent aggregation. Binding modes of compounds have been visualised by crystallography. In vitro neuroprotection and toxicity of lead compounds have been performed in mouse neuronal cells and disease onset delay of ebselen has been demonstrated in transgenic ALS mice model.

Finding

We have developed a number of ebselen-based compounds with improvements in A4V SOD1 stabilisation and in vitro therapeutic effects with significantly better potency than edaravone. Structure-activity relationship of hits has been guided by high resolution structures of ligand-bound A4V SOD1. We also show clear disease onset delay of ebselen in transgenic ALS mice model holding encouraging promise for potential therapeutic compounds.

Interpretation

Our finding established the new generation of organo-selenium compounds with better in vitro neuroprotective activity than edaravone. The potential of this class of compounds may offer an alternative therapeutic agent for ALS treatment. The ability of these compounds to target cysteine 111 in SOD may have wider therapeutic applications targeting cysteines of enzymes involved in pathogenic and viral diseases including main protease of SARS-Cov-2 (COVID-19).

Funding

Project funding was supported by the 10.13039/100000971ALS Association grant (WA1128) and Fostering Joint International Research (19KK0214) from the 10.13039/100009950Ministry of Education, Culture, Sports, Science and Technology (10.13039/501100001700MEXT), Japan.

SAT0262 PROPOSAL FOR OPTIMIZATION OF DIAGNOSTIC IMAGING FOR GIANT CELL ARTERITIS USING THREE-DIMENSIONAL COMPUTED TOMOGRAPHY ANGIOGRAPHY IMAGE AND CONSTRUCTING VASCULAR MAPPING FROM VASCULAR ULTRASONOGRAPHY AS REFERENCES

Background:

The development of rapid and accurate methods of diagnosing giant cell arteritis (GCA) is critical to prevent blindness and stroke, which may develop rapidly in patients with GCA. In 2018, EULAR published recommendations that the first imaging modality for GCA should be vascular ultrasonography without biopsy. However, many institutions still consider biopsy to make an important contribution to the diagnosis of GCA.

Objectives:

Our purpose is to eliminate blindness and stroke among GCA patients by optimizing diagnostic imaging and method to diagnose GCA employed by vascular ultrasonography (V-US), CT Angiography (CTA), MRI/A, and PET/CT without biopsy.

Methods:

We evaluated the clinical and serological characteristics of 20 patients who were diagnosed with GCA at our hospital from 2012 to 2018, and compared the image and biopsy findings of these patients. We then evaluated the effect of optimizing diagnostic imaging and methods for patients with suspected GCA who visited our hospital during 2019. Vascular mapping was carried out using V-US for 3DCTA and other imaging methods as references.

Results:

Table 1 shows the clinical characteristics of the study population. The sensitivity of CTA for GCA was 85.7% (12 of 14 patients), which was the highest of the studied imaging methods. All biopsy-positive cases were diagnosed as GCA, and we compared these cases with cases with positive imaging findings. This revealed that CTA findings were correct (i.e., positive) in 66.7% (four of six patients), MRI/A findings were correct in in 33.3% (three of nine), V-US findings were correct in 50.0% (three of six). Therefore, CTA exhibited the highest sensitivity for positive findings. Comparison of biopsy-positive cases with cases in which imaging findings were negative revealed that CTA findings were correct (negative) in 33.3% (two of six patients), MRI/A findings were correct in 55.6% (five of nine), V-US was correct in 50.0% (three of six). Thus, CTA had the lowest sensitivity for negative findings. Comparison of CTA findings of positive cases with other imaging modalities which reported positive findings revealed MRI/A findings to be correct in 44.4% (four of nine patients), PET/CT findings to be correct in 50.0% (one of two), V-US to be correct in 63.3% (five of eight). Thus, V-US had the highest agreement with CTA. We carried out vascular mapping by V-US using 3DCTA and other imaging methods and produced references to improve the accuracy of diagnosis. Using these references, we diagnosed five cases of GCA among the 20 patients; the positive predictive value of V-US was 80% (four of five patients) and negative predictive value was 86.7% (13 of 15 patients).

Table 1.

Baseline characteristics of the study sample

    

The number of biopsies performed decreased from 50% (10 of 20 patients) from 2012 to 2018 to 15% (3 of 20 patients) in 2019. Two cases in the present study had positive findings in both biopsy and V-US; in one case, biopsy, CTA, and MRI/A were negative while V-US revealed positive findings. No patients with GCA developed blindness or stroke during 2019.

Conclusion:

We propose that V-US should be performed as the first examination for the diagnosis of GCA by the creation of vascular mappings when GCA is suspected in order to prevent blindness and stroke.

References:

[1]Christian Dejaco et al.EULAR recommendations for the use of imaging in large vasculitis in clinical practice.Annals of the Rheumatic Diseases,2018 May;77(5):636-643

[2]Kawamoto T et al.Diagnosis of giant cell arthritis by head-contrast three-dimensional computed tomography angiography.Journal of Medical Case Reports2019 Sep 11;13(1):285.

Figure 1.

Left side is before, right side is after thrapy. (A) 3DCTA finding, (B) determination of V-US arrangement with vascular location to evaluate wall thickening of V-US, compression sign, stenosis and stoppage of vessels.

Disclosure of Interests:

None declared

FRI0179 A STUDY ON THE ACHIEVEMENT OF LUPUS LOW DISEASE ACTIVITY STATE AND QUALITY OF LIFE IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: FROM THE JUNTENDO UNIVERSITY SLE PROSPECTIVE REGISTRY STUDY

Background:

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that affects mostly young women. Multiorgan complications and prolonged treatment significantly cause physical and mental stress in patients. Improving patients’ quality of life (QOL) in SLE treatment is essential. We examined the treatment effects on disease activity and QOL of SLE patients.

Objectives:

In recent years, lupus low disease activity state (LLDAS) has been proposed as a treatment target for SLE. Patients who achieve LLDAS have a low recurrence rate for lupus and a low risk of serious complications (1). The aim of this study is to investigate whether achieving LLDAS reduces not only recurrence rate and complications of SLE but also improves patients’ QOL.

Methods:

A total of 104 SLE patients were enrolled in our prospective SLE registry study (Juntendo, Multi-center, Prospective cohort for investigation of clinical course and outcome in SLE: JUMP) conducted at our institution. SLE was diagnosed using the American College of Rheumatology (ACR) 1982 criteria (revised in 1997). QOL was evaluated using the standard version of the 36-item short form health survey version 2 (SF36v2). Participants were divided into the LLDAS achievement and non-achievement groups, and the characteristics of each group including results of SF36v2 were examined.

Results:

This study included 104 SLE patients, 94 female and 10 male, and the average age and disease duration were 46.4±13.8 and 14.5±11.3 years, respectively. The average corticosteroid dose was 8.0±17.4 mg/day in terms of prednisolone, and anti-dsDNA antibody titer was 16.8±38.5 IU/ml. Of the 104 patients, 57 achieved LLDAS. The subscale’s standard scoring using SF36v2 for role physical (RP) was 78.9±24.0 and 64.6±27.6 (P<0.01), general health (GH) was 50.0±17.0 and 42.0±19.3 (P<0.05), vitality (VT) was 55.8±15.8 and 38.0±24.1 (P<0.01), social functioning (SF) was 82.0±20.7 and 66.5±26.3 (P<0.01), role emotional (RE) was 89.0±16.1 and 73.4±28.1 (P<0.01), and mental health (MH) was 72.4±15.9 and 58.3±21.8 (P<0.01) in the LLDAS achievement and non-achievement groups, respectively. Furthermore, scoring based on the national standard value in the LLDAS achievement group showed that two categories were >50. However, in the LLDAS non-achievement group, all categories were <50. In particular, RP, GH, VT, SF, RE, and MH of the LLDAS achievement group had significantly higher scores than the LLDAS non-achievement group (RP and GH: p<0.05 and VT, SF, RE and MH: p<0.01).

Conclusion:

Results of examining the association between LLDAS and QOL using SF36v2 in SLE patients showed that patients who achieved LLDAS had significantly better standard statistical scores in many subscale categories. Thus, LLDAS achievement as a treatment target for SLE patients greatly contributes to improving patients’ QOL.

References:

[1]Franklyn K, et al. Definition and initial validation of a Lupus Low Disease Activity State (LLDAS).Ann Rheum Dis. 2016 Sep;75(9):1615-21.

Disclosure of Interests:

None declared

Ubiquitination of DNA Damage-Stalled RNAPII Promotes Transcription-Coupled Repair

Transcription-coupled nucleotide excision repair (TC-NER) is initiated by the stalling of elongating RNA polymerase II (RNAPIIo) at DNA lesions. The ubiquitination of RNAPIIo in response to DNA damage is an evolutionarily conserved event, but its function in mammals is unknown. Here, we identified a single DNA damage-induced ubiquitination site in RNAPII at RPB1-K1268, which regulates transcription recovery and DNA damage resistance. Mechanistically, RPB1-K1268 ubiquitination stimulates the association of the core-TFIIH complex with stalled RNAPIIo through a transfer mechanism that also involves UVSSA-K414 ubiquitination. We developed a strand-specific ChIP-seq method, which revealed RPB1-K1268 ubiquitination is important for repair and the resolution of transcriptional bottlenecks at DNA lesions. Finally, RPB1-K1268R knockin mice displayed a short life-span, premature aging, and neurodegeneration. Our results reveal RNAPII ubiquitination provides a two-tier protection mechanism by activating TC-NER and, in parallel, the processing of DNA damage-stalled RNAPIIo, which together prevent prolonged transcription arrest and protect against neurodegeneration.

ALS-linked TDP-43M337V knock-in mice exhibit splicing deregulation without neurodegeneration

Abnormal accumulation of TAR DNA-binding protein 43 (TDP-43), a DNA/RNA binding protein, is a pathological signature of amyotrophic lateral sclerosis (ALS). Missense mutations in the TARDBP gene are also found in inherited and sporadic ALS, indicating that dysfunction in TDP-43 is causative for ALS. To model TDP-43-linked ALS in rodents, we generated TDP-43 knock-in mice with inherited ALS patient-derived TDP-43^M337V mutation. Homozygous TDP-43^M337V mice developed normally without exhibiting detectable motor dysfunction and neurodegeneration. However, splicing of mRNAs regulated by TDP-43 was deregulated in the spinal cords of TDP-43^M337V mice. Together with the recently reported TDP-43 knock-in mice with ALS-linked mutations, our finding indicates that ALS patient-derived mutations in the TARDBP gene at a carboxyl-terminal domain of TDP-43 may cause a gain of splicing function by TDP-43, however, were insufficient to induce robust neurodegeneration in mice.

34 Effect of polysaccharide from Flammulina velutipes on the vitrification of bovine oocytes

The developmental competence of oocytes after cryopreservation is compromised by the physical injury due to the ice crystallisation. Recent studies have reported that polysaccharide (xylomannan) derived from the mycelium and fruit body of the basidiomycete Flammulina velutipes inhibits the ice recrystallisation in the cryopreserved Chinese hamster ovary cells. In this study, we aimed to clarify the effect of xylomannan from Flammulina velutipes on the developmental competence of bovine vitrified oocytes. Bovine ovaries were obtained from a local abattoir, and cumulus-oocyte complexes (COCs) were aspirated from follicles (2-6mm in diameter) using a 19-gauge needle attached to a syringe. The COCs were matured for 22h in tissue culture medium-199 supplemented with 5% fetal bovine serum (FBS), 0.02IUmL−1 FSH, and 10μgmL−1 gentamycin. After maturation, COCs were incubated in base solution (BS: 10% FBS-tissue culture medium-199, control group; n=149) or BS supplemented with 100μgmL−1 xylomannan (xylomannan group; n=175) for 1h before vitrification. All vitrification procedures were performed at room temperature. The COCs were equilibrated in BS with 3% ethylene glycol for 12min and then in vitrification solution (BS with 30% ethylene glycol, 1.0M sucrose) for 1min. The COCs were loaded on a Cryotop (Kitazato) and transferred into liquid nitrogen. The warming procedure was performed on a warm plate (42°C). The COCs were placed into BS supplemented with 0.5, 0.25, 0.125, and 0M sucrose for 5min each. After washing with IVF100 solution (Research Institute for the Functional Peptide), COCs were applied for IVF. The viability of putative zygotes was morphologically evaluated following IVF, and ones that survived were cultured in CR1aa supplemented with 5% FBS. The cleavage pattern was evaluated at 28h after IVF as follows: embryos with blastomeres of the same size without fragmentation were classified as normal cleavage; embryos with 2 blastomeres and several small fragments, direct cleavage from the 1-cell stage to 3 or 4 blastomeres, or 2 blastomeres of different size were classified as abnormal cleavage. The rates of cleavage and blastocyst formation were calculated on 2 and 8 days after culture, respectively. Total cell number and apoptosis of blastocysts were measured by terminal deoxynucleotidyl transferase dUTP nick end labelling assay. All data were obtained from more than four replicates. Viability and invitro development data were analysed using the chi-squared test. Total cell number and apoptosis data were analysed by a Student's t-test. Although no significant differences in viability, cleavage pattern, and cleavage rate (85.8 vs. 80.3%, 17.2 vs. 14.8%, and 35.4 vs. 36.7%, respectively) were observed, the developmental rate to blastocysts in the xylomannan group was significantly higher than that in the control group (68.6 vs. 42.2%; P&lt;0.01). The present results suggest that co-incubation with xylomannan before vitrification is an effective method to improve the vitrification outcome in bovine oocytes.

P175 Prognostic value of 99mTc-ECD brain perfusion SPECT in patients with atrial fibrillation and dementia

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and those afflicted have reduced quality of life, functional status, and cardiac performance. The patients with AF have a high risk of coronary heart disease and cardiovascular disease. Although the prevalence of AF is increasing, cognitive disorders are also on the rise in tandem with the aging of the population. The patients with dementia have also experienced lower the quality of life and have increased mortality. Technetium 99m ECD brain perfusion single photon emission computed tomography (99mTc-ECD brain perfusion SPECT) is a useful modality for diagnosing dementia and identifying high risk patients with mild cognitive impairment. However, there are few reports about the relationship between the value of Z score calculated by 99mTc-ECD brain perfusion SPECT and prognosis of patients with AF and dementia.

Purpose

The aim of this study was to evaluate the prognostic values of brain perfusion using 99mTc-ECD SPECT in patients with AF and dementia.

Methods

Among 405 consecutive patients who were diagnosed as AF in cardiac outpatients and subsequently diagnosed as dementia using Mini-Mental State Examination by neurologists or psychiatrists, we identified 170 patients (81 ± 10 years) who underwent 99mTc-ECD brain perfusion SPECT for the current study. Of those, 73, 73, and 24 were diagnosed as Alzheimer’s dementia (AD), vascular dementia (VD), and non-specified dementia respectively. Multivariate Cox model was used to assess if higher Z score by 99mTc-ECD brain perfusion SPECT and clinical parameters were associated with major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, hospitalization for heart failure, and stroke. Sub-analyses of multivariate Cox models by AD or VD were also assessed. The cut-off values of Z score were determined using area under the curve by a receiver operating characteristic analysis based on MACE occurrences.

Results

During a mean follow-up of 1258 ± 1044 days, 62 MACE occurred. There was not significant difference of MACE between AD and VD (33%, vs. 44%, p = 0.153). By multivariable Cox model, the higher Z score of temporal-occipital-pariental lobe was associated with increased MACE compared to the lower group (HR 2.521, 95% CI 1.465–4.337, p &lt; 0.001). In a sub-analysis of patients with AD, Z score was the most significant prognostic factor for MACE (HR 3.969, 95% CI 1.374–11.468, p = 0.011). The similar trend was observed in those with VD (HR 2.247, 95% CI 1.028–4.913, p = 0.043). Conclusion: This study demonstrated that the Z score of temporal-occipital-pariental lobe by 99mTc-ECD brain perfusion SPECT could be a potential prognostic value among patients with AF and dementia, regardless of type of dementia.

An indirect comparison of long-term efficacy of every-2-week dosing vs. recommended dosing of ixekizumab in patients who had static Physician's Global Assessment > 1 at week 12

BACKGROUND

Long-term efficacy and safety of ixekizumab [160 mg at week 0, then 80 mg every 2 weeks (Q2W) for 12 weeks, followed by every 4 weeks (Q4W) thereafter (i.e. Q2W/Q4W), which is the labelled psoriasis dosing where approved, except in Japan] have been established for the treatment of adults with moderate-to-severe plaque psoriasis. However, some patients may benefit from remaining on Q2W dosing beyond 12 weeks.

METHODS

Among patients who had static Physician's Global Assessment (sPGA) > 1 at week 12, efficacy through week 52 of continuous Q2W dosing in the IXORA-P study was compared indirectly with Q2W/Q4W in the integrated data from the UNCOVER-1, UNCOVER-2 and UNCOVER-3 studies. The continuous Q4W dose group, which had comparable results across studies, was used as the common comparator.

RESULTS

In the IXORA-P study, among patients with sPGA > 1 at week 12, 64% of patients in the continuous Q2W group achieved sPGA ≤ 1 at week 52, which was statistically significantly higher than the 36% of patients with sPGA > 1 in the Q2W/Q4W group based on the integrated data from the UNCOVER studies (P = 0·0007). There were no clinically meaningful differences in frequencies of safety events between patients with sPGA ≤ 1 and patients with sPGA > 1 at week 12 in the IXORA-P study.

CONCLUSIONS

Among patients who did not have clear or almost clear skin at week 12, nearly 30% more patients who were treated continuously with ixekizumab Q2W in IXORA-P had clear or almost clear skin at week 52 when compared indirectly with those who were treated using the labelled psoriasis dosing in integrated UNCOVER studies. What's already known about this topic? Most patients with moderate-to-severe psoriasis who were given the labelled psoriasis dosing of ixekizumab [160-mg loading dose at week 0, 80 mg every 2 weeks (Q2W) through week 12, and 80 mg every 4 weeks (QW4) thereafter] respond quickly with a high percentage of skin clearance. Additionally, patients who achieve static Physician's Global Assessment (sPGA) ≤ 1 by week 12 tend to maintain this response, even after switching to Q4W. What does this study add? Here, we assessed whether patients with sPGA > 1 at week 12 benefited from receiving more frequent dosing beyond the first 12 weeks. The results showed that Q2W dosing beyond 12 weeks resulted in more patients achieving sPGA ≤ 1 by week 52 than the labelled psoriasis dosing among patients with sPGA > 1 at week 12.

Mice deficient in the C-terminal domain of TAR DNA-binding protein 43 develop age-dependent motor dysfunction associated with impaired Notch1-Akt signaling pathway

Intracellular mislocalization of TAR DNA-binding protein 43 (TDP-43), a nuclear DNA/RNA-binding protein involved in RNA metabolism, is a pathological hallmark of amyotrophic lateral sclerosis (ALS). Although the aggregation-prone, TDP-43 C-terminal domain is widely considered as a key component of TDP-43 pathology in ALS, recent studies including ours suggest that TDP-43 N-terminal fragments (TDP-∆C) may also contribute to the motor dysfunction in ALS. However, the specific pathological functions of TDP-43 N-terminal fragments in mice have not been elucidated. Here, we established TDP-∆C knock-in mice missing a part of exon 6 of murine Tardbp gene, which encodes the C-terminal region of TDP-43. Homozygous TDP-∆C mice showed embryonic lethality, indicating that the N-terminal domain of TDP-43 alone is not sufficient for normal development. In contrast, heterozygous TDP-∆C mice developed normally but exhibited age-dependent mild motor dysfunction with a loss of C-boutons, large cholinergic synaptic terminals on spinal α-motor neurons. TDP-∆C protein broadly perturbed gene expression in the spinal cords of aged heterozygous TDP-∆C mice, including downregulation of Notch1 mRNA. Moreover, the level of Notch1 mRNA was suppressed both by TDP-43 depletion and TDP-∆C expression in Neuro2a cells. Decreased Notch1 mRNA expression in aged TDP-∆C mice was associated with the age-dependent motor dysfunction and loss of Akt surviving signal. Our findings indicate that the N-terminal region of TDP-43 derived from TDP-∆C induces the age-dependent motor dysfunction associated with impaired Notch1-Akt axis in mice.

The influence of temperature during water-quench rapid heat treatment on the microstructure, mechanical properties and biocompatibility of Ti6Al4V ELI alloy

This study investigates the influence of a rapid heat treatment followed by water-quenching on the mechanical properties of Ti6Al4V ELI alloy to improve its strength for use in implants. Prior to the experiment, a dilatometry test was performed to understand the progressive α-to β-phase transformation taking place during heating. The results were then used to carry out heat treatments. Microstructure was analysed using SEM, EBSD, EDX and XRD techniques. Vickers micro-hardness, tensile and high cycle rotating bending tests were used to analyse the influence of the $\alpha'$-phase fraction on the strength of the studied alloy. Results show that this process can provide a Ti6Al4V ELI alloy with a better Yield Strength (YS)/uniform deformation (ε_u) ratio and improved high cycle fatigue strength than those observed in the current microstructure used in medical implants. Lastly, cytotoxicity tests were performed on two types of human cells, namely MG63 osteoblast-like cells and fibroblasts. The results reveal the non-toxicity of the heat-treated Ti6Al4V ELI alloy.

136 Efficient in vitro embryo production system using in vivo-matured oocytes from superstimulated Japanese black cows

In this study, we examined whether in vivo matured oocytes collected by ovum pickup (OPU) from superstimulated Japanese black cows can improve the productivity and quality of in vitro-produced embryos. Cows in the stimulated group received an intravaginal progesterone-releasing device (Day 0), administration of 100μg of GnRH on Day 5, a single administration of 30 Armour units of FSH on the evening of Day 8 and prostaglandin F2α on the evening of Day 10. The progesterone device was removed on the morning of Day11, and then 100μg of GnRH was administered on the morning of Day 12 (0 h). The OPU and IVF were conducted at 25~26 and 30h, respectively. Cows in the control group received no treatment before OPU, and collected oocytes were subjected to in vitro maturation followed by IVF. The cortical granules distribution of oocytes at metaphase II stage, the cleavage pattern of embryos at the first cell cycle, the developmental rate, and the quality of blastocysts were compared between the stimulated and control groups. Oocytes with cortical granules distributing cortical cytoplasm were classified as normal distribution. The cleavage pattern was evaluated at 28h after IVF as follows: embryos with blastomeres of the same size without fragmentation were classified as normal cleavage; embryos with 2 blastomeres and several small fragments, direct cleavage from the one-cell stage to 3 or 4 blastomeres, or 2 blastomeres of different size were classified as abnormal cleavage. The developmental rate to blastocyst stage was measured on Day 9 of culture. The morphological quality of blastocysts was evaluated based on the IETS manual. All data were obtained from more than 3 replicates. In vitro development and cortical granules distribution data were analysed using chi-squared test. Other data were analysed using Student’s t-test. Normal cortical granules distribution rate in the stimulated group was higher than that in the control group (90.3v. 23.1%; P&lt;0.01). Although no differences in the developmental rate to blastocyst stage (51.5v. 58.6%) was observed, the normal cleavage rate (73.4v. 51.2%) and the transferable embryo rate (98.3v. 88.0%) in the stimulated group were significantly higher (P&lt;0.01) than those in the control group. The ratio of embryos from normal cleavage among the transferable embryos in the stimulated group was also significantly higher than in the control group (82.2v. 57.2%; P&lt;0.01). In addition, the freezable embryo ratio (71.7v. 58.1%; P&lt;0.072) and the total production number of embryos per head (28.0v. 15.5; P&lt;0.106) showed a tendency to be higher in the stimulated group than in the control group. These results suggest that high quality embryos can be efficiently produced by the use of in vivo matured oocytes collected by OPU from superstimulated Japanese black cows.

Phenotypic heterogeneity of astrocytes in motor neuron disease

Accumulating evidence has shown that astrocytes do not just support the function of neurons, but play key roles in maintaining the brain environment in health and disease. Contrary to the traditional understanding of astrocytes as static cells, reactive astrocytes possess more diverse functions and phenotypes than previously predicted. In the present focused review, we summarize the evidence showing that astrocytes are playing profound roles in the disease process of amyotrophic lateral sclerosis. Aberrantly activated astrocytes in amyotrophic lateral sclerosis rodents express microglial molecular markers and provoke toxicities to accelerate disease progression. In addition, TIR domain–containing adapter protein–inducing interferon‐β‐dependent innate immune pathway in astrocytes also has a novel function in terminating glial activation and neuroinflammation. Furthermore, heterogeneity in phenotypes and functions of astrocytes are also observed in various disease conditions, such as other neurodegenerative diseases, ischemia, aging and acute lesions in the central nervous system. Through accumulating knowledge of the phenotypic and functional diversity of astrocytes, these cells will become more attractive therapeutic targets for neurological diseases.

Amiodarone does not affect brain injury in a rat model of transient forebrain ischemia

OBJECTIVES

Although amiodarone may cause neurotoxicity that can affect patient outcomes when used during cardiopulmonary resuscitation (CPR), it has been commonly prescribed during CPR. This study investigated the possible neurotoxic effects of amiodarone in a rat model of transient forebrain ischemia.

DESIGN

A prospective laboratory animal study was carried out.

SETTING

Animal laboratory.

MATERIALS

Male Sprague-Dawley rats.

INTERVENTION

Eight minutes of forebrain ischemia was induced in rats by bilateral carotid occlusion and hypotension (mean arterial pressure=35mmHg) under isoflurane (1.5%) anesthesia. Amiodarone (0, 50, 100 and 150mg/kg) with saline was injected intraperitoneally 10min after ischemia. Rats given 0mg/kg of amiodarone were used as saline-treated controls. Sham operated rats received no treatment.

VARIABLES OF INTEREST

Animals were evaluated neurologically on postoperative days 4-7, and histologically after a one-week recovery period.

RESULTS

The greatest improvement in water maze test performance corresponded to the sham operated group (p=0.015 vs. saline-treated controls). No differences in performance were seen in amiodarone-treated rats compared with saline-treated controls. In the control group, 45% of the CA1 hippocampal neurons survived, compared with 78% in the sham operated group (p=0.009). Neuron survival after ischemia in the amiodarone treatment groups (50, 100 and 150mg/kg) (58%, 40% and 36%, respectively) and in the control rats did not differ significantly.

CONCLUSIONS

The administration of amiodarone immediately after transient forebrain ischemia did not worsen spatial cognitive function or neuronal survival in the hippocampal CA1 region in rats. The current results must be applied with caution in humans. However, they indicate that the potential neurotoxicity induced by amiodarone during resuscitation after cardiac arrest may be negligible.

Innate immune adaptor TRIF deficiency accelerates disease progression of ALS mice with accumulation of aberrantly activated astrocytes

There is compelling evidence that glial-immune interactions contribute to the progression of neurodegenerative diseases. The adaptive immune response has been implicated in disease processes of amyotrophic lateral sclerosis (ALS), but it remains unknown if innate immune signaling also contributes to ALS progression. Here we report that deficiency of the innate immune adaptor TIR domain-containing adaptor inducing interferon-β (TRIF), which is essential for certain Toll-like receptor (TLR) signaling cascades, significantly shortens survival time and accelerates disease progression of ALS mice. While myeloid differentiation factor 88 (MyD88) is also a crucial adaptor for most TLR signaling pathways, MyD88 deficiency had only a marginal impact on disease course. Moreover, TRIF deficiency reduced the number of natural killer (NK), NK-T-lymphocytes, and CD8-T cells infiltrating into the spinal cord of ALS mice, but experimental modulation of these populations did not substantially influence survival time. Instead, we found that aberrantly activated astrocytes expressing Mac2, p62, and apoptotic markers were accumulated in the lesions of TRIF-deficient ALS mice, and that the number of aberrantly activated astrocytes was negatively correlated with survival time. These findings suggest that TRIF pathway plays an important role in protecting a microenvironment surrounding motor neurons by eliminating aberrantly activated astrocytes.

A copper-deficient form of mutant Cu/Zn-superoxide dismutase as an early pathological species in amyotrophic lateral sclerosis

Dominant mutations in the gene encoding copper and zinc-binding superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS). Abnormal accumulation of misfolded SOD1 proteins in spinal motoneurons is a major pathological hallmark in SOD1-related ALS. Dissociation of copper and/or zinc ions from SOD1 has been shown to trigger the protein aggregation/oligomerization in vitro, but the pathological contribution of such metal dissociation to the SOD1 misfolding still remains obscure. Here, we tested the relevance of the metal-deficient SOD1 in the misfolding in vivo by developing a novel antibody (anti-apoSOD), which exclusively recognized mutant SOD1 deficient in metal ions at its copper-binding site. Notably, anti-apoSOD-reactive species were detected specifically in the spinal cords of the ALS model mice only at their early pre-symptomatic stages but not at the end stage of the disease. The cerebrospinal fluid as well as the spinal cord homogenate of one SOD1-ALS patient also contained the anti-apoSOD-reactive species. Our results thus suggest that metal-deficiency in mutant SOD1 at its copper-binding site is one of the earliest pathological features in SOD1-ALS.