Spinal cord extracts of amyotrophic lateral sclerosis spread TDP-43 pathology in cerebral organoids.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder caused by progressive loss of motor neurons and there is currently no effective therapy. Cytoplasmic mislocalization and aggregation of TAR DNA-binding protein 43 kDa (TDP-43) within the CNS is a pathological hallmark in sporadic ALS and prion-like propagation of pathogenic TDP-43 is thought to be implicated in disease progression. However, cell-to-cell transmission of pathogenic TDP-43 in the human CNS has not been confirmed experimentally. Here we used induced pluripotent stem cells (iPSCs)-derived cerebral organoids as recipient CNS tissue model that are anatomically relevant human brain. We injected postmortem spinal cord protein extracts individually from three non-ALS or five sporadic ALS patients containing pathogenic TDP-43 into the cerebral organoids to validate the templated propagation and spreading of TDP-43 pathology in human CNS tissue. We first demonstrated that the administration of spinal cord extracts from an ALS patient induced the formation of TDP-43 pathology that progressively spread in a time-dependent manner in cerebral organoids, suggesting that pathogenic TDP-43 from ALS functioned as seeds and propagated cell-to-cell to form de novo TDP-43 pathology. We also reported that the administration of ALS patient-derived protein extracts caused astrocyte proliferation to form astrogliosis in cerebral organoids, reproducing the pathological feature seen in ALS. Moreover, we showed pathogenic TDP-43 induced cellular apoptosis and that TDP-43 pathology correlated with genomic damage due to DNA double-strand breaks. Thus, our results provide evidence that patient-derived pathogenic TDP-43 can mimic the prion-like propagation of TDP-43 pathology in human CNS tissue. Our findings indicate that our assays with human cerebral organoids that replicate ALS pathophysiology have a promising strategy for creating readouts that could be used in future drug discovery efforts against ALS.

Tau beyond Tangles: DNA Damage Response and Cytoskeletal Protein Crosstalk on Neurodegeneration.

Neurons in the brain are continuously exposed to various sources of DNA damage. Although the mechanisms of DNA damage repair in mitotic cells have been extensively characterized, the repair pathways in post-mitotic neurons are still largely elusive. Moreover, inaccurate repair can result in deleterious mutations, including deletions, insertions, and chromosomal translocations, ultimately compromising genomic stability. Since neurons are terminally differentiated cells, they cannot employ homologous recombination (HR) for double-strand break (DSB) repair, suggesting the existence of neuron-specific repair mechanisms. Our research has centered on the microtubule-associated protein tau (MAPT), a crucial pathological protein implicated in neurodegenerative diseases, and its interplay with neurons' DNA damage response (DDR). This review aims to provide an updated synthesis of the current understanding of the complex interplay between DDR and cytoskeletal proteins in neurons, with a particular focus on the role of tau in neurodegenerative disorders.

Clinical Features and Neuroimaging Findings of Neuropil Antibody-Positive Idiopathic Sporadic Ataxia of Unknown Etiology.

Idiopathic sporadic ataxia (ISA) is the clinical term for nonfamilial ataxia with adult-onset and a slowly progressive course. However, immune-mediated cerebellar ataxia cannot be completely excluded from ISA. The current study investigated the neuropil antibodies against cell-surface antigens and clarified the clinical features and neuroimaging findings of patients with these antibodies. Using tissue-based immunofluorescence assays (TBAs), we examined antibodies against the cerebellum in serum samples from 67 patients who met the ISA diagnostic criteria, including 30 patients with multiple system atrophy with predominant cerebellar features (MSA-C) and 20 patients with hereditary ataxia (HA), and 18 healthy control subjects. According to the TBA results, we divided subjects into three groups: subjects positive for neuropil antibodies, subjects positive for intracellular antibodies only, and subjects negative for antibodies. We compared clinical features and neuroimaging findings in ISA patients among these three groups. The prevalence of neuropil antibodies in ISA (17.9%) was significantly higher than that in MSA-C (3.3%), HA (0%), or healthy subjects (0%). The neuropil antibody-positive ISA patients showed pure cerebellar ataxia more frequently than the other ISA patients. Two neuropil antibody-positive patients showed significant improvement of cerebellar ataxia after immunotherapy. We detected neuropil antibodies in 17.9% of ISA patients. Characteristic clinical features of neuropil antibody-positive ISA patients were pure cerebellar ataxia. Some cases of neuropil antibody-positive ISA responded to immunotherapy.

Control of Diabetes Mellitus and Long-Term Prognosis in Stroke Patients: The Shiga Stroke and Heart Attack Registry.

BACKGROUND: The relationship between diabetes control status and long-term prognosis after stroke incidence remains unclear. This study aimed to investigate the effect of diabetes status at admission on long-term survival in patients with first-ever stroke. METHODS: A retrospective cohort study was conducted based on the Shiga Stroke and Heart Attack Registry in Japan. Patients were classified according to their diabetes status and glycated hemoglobin (HbA1c) value at hospital admission into the following: (1) free of diabetes (no history of diabetes and HbA1c <6.5%); (2) good control (history of diabetes and HbA1c <7%; free of history and 6.5% ≤HbA1c <7%); and (3) poor control (with or without a history of diabetes and HbA1c ≥7%). Multivariable Cox regression models were used to evaluate the association between diabetes status and long-term survival from stroke onset. Additionally, we also evaluated the association between diabetes status and conditional survival, beginning 29 days after stroke onset. RESULTS: A total of 6,331 first-ever stroke patients were eligible for this study. Among study patients, the mean (±SD) age was 72.85 ± 13.19 years, and the mean (±SD) follow-up year was 2.76 ± 1.66 years; additionally, 42.09% of patients were women. Among patients with all strokes, considering the free-of-diabetes group as the reference group, the adjusted hazard ratio (95% confidence interval) for mortality was 1.26 (1.10, 1.44) in the good control group and 1.22 (1.05, 1.41) in the poor control group. Among patients with ischemic stroke, the adjusted hazard ratio was 1.24 (1.06, 1.46) in good control group and 1.27 (1.08, 1.50) in poor control group. After excluding patients who died within 28 days, the adjusted hazard ratio for conditional mortality in the poor control group was 1.31 (1.12, 1.54) among all stroke patients and 1.29 (1.08, 1.54) among ischemic stroke patients. No significant associations were observed between diabetic status and long-term mortality in intracerebral hemorrhage patients. CONCLUSIONS: The findings suggest that first-ever stroke patients with diabetes exhibited a higher risk of all-cause mortality than those without diabetes, particularly in the overall stroke and ischemic stroke populations. Additionally, in stroke populations after 28 days of onset, high risk of long-term mortality was stated in stroke patients with poor HbA1c control.

Nuclear Expression of TDP-43 Is Linked with Morphology and Ubiquitylation of Cytoplasmic Aggregates in Amyotrophic Lateral Sclerosis.

The transactive response DNA-binding protein of 43 kDa (TDP-43) is a pathological protein of amyotrophic lateral sclerosis (ALS). TDP-43 pathology is characterized by a combination of the cytoplasmic aggregation and nuclear clearance of this protein. However, the mechanisms underlying TDP-43 pathology have not been fully clarified. The aim of this study was to evaluate the relationships between the expression level of nuclear TDP-43 and the pathological properties of cytoplasmic aggregates in autopsied ALS cases. We included 22 consecutively autopsied cases with sporadic TDP-43-related ALS. The motor neuron systems were neuropathologically assessed. We identified 790 neurons with cytoplasmic TDP-43 inclusions from the lower motor neuron system of included cases. Nuclear TDP-43 disappeared in 84% (n = 660) and expressed in 16% (n = 130) of neurons with cytoplasmic inclusions; the former was defined as TDP-43 cytoplasmic immunoreactivity (c-ir), and the latter was defined as nuclear and cytoplasmic immunoreactivity (n/c-ir). Morphologically, diffuse cytoplasmic inclusions were significantly more prevalent in TDP-43 n/c-ir neurons than in c-ir neurons, while skein-like and round inclusions were less prevalent in n/c-ir neurons. The cytoplasmic inclusions of TDP-43 n/c-ir neurons were phosphorylated but poorly ubiquitylated when compared with those of c-ir neurons. TDP-43 n/c-ir neurons became less dominant than the c-ir neurons among cases with a prolonged disease duration. The expression level of nuclear TDP-43 was significantly lower in n/c-ir neurons than in normal neurons without cytoplasmic inclusions. Our results indicate that the maturation of cytoplasmic TDP-43 inclusions correlates with the depletion of nuclear TDP-43 in each affected neuron. This finding supports the view that an imbalance between nuclear and cytoplasmic TDP-43 may be an essential pathway to TDP-43 pathology.

Bone marrow-derived inducible microglia-like cells ameliorate motor function and survival in a mouse model of amyotrophic lateral sclerosis.

BACKGROUND AIMS: Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease. Neuroinflammation in the spinal cord plays a pivotal role in the pathogenesis of ALS, and microglia are involved in neuroinflammation. Microglia mainly have two opposite phenotypes involving cytotoxic and neuroprotective properties, and neuroprotective microglia are expected to be a novel application for the treatment of ALS. Therefore, to establish a clinically applicable therapeutic method using neuroprotective microglia, the authors investigated the effect of inducing neuroprotective microglia-like cells from bone marrow for transplantation into ALS model mice. METHODS: Bone marrow-derived mononuclear cells were isolated from green fluorescent protein mice and cultured using different protocols of cytokine treatment with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4. Cells with a high potency of proliferation and differentiation into microglia were evaluated by gene analysis, flow cytometry and direct neuroprotective effects in vitro. These cells were named bone marrow-derived inducible microglia-like (BM-iMG) cells and transplanted into the spinal cords of ALS model mice, and behavioral tests, immunohistochemistry and gene expression profiling were performed. RESULTS: Three-day GM-CSF and 4-day GM-CSF + IL-4 stimulations were most effective in inducing BM-iMG cells from the bone marrow. Transplantation of BM-iMG cells improved motor function, prolonged survival and suppressed neuronal cell death, astrogliosis and microgliosis in the spinal cords of ALS mice. Moreover, neuroprotective genes such as Arg1 and Mrc1 were upregulated, whereas pro-inflammatory genes such as Nos2 and Il6 were downregulated. CONCLUSIONS: Intraspinal transplantation of BM-iMG cells demonstrated therapeutic effects in a mouse model of ALS. Further studies and clinical applications in patients with ALS are expected in the future.

Seasonal Variation in Incidence of Stroke in a General Population of 1.4 Million Japanese: The Shiga Stroke Registry.

INTRODUCTION: The purpose of this study was to investigate seasonal variation in stroke incidence using data from a large-scale stroke registry of general population in current Japan. METHODS: Shiga Stroke Registry (SSR) is an ongoing population-based registry of stroke that occurred in the Shiga Prefecture in central Honshu, Japan. A total 6,688 cases of first-ever stroke, with onset dates ranging from 1 January 2011 to 31 December in 2013 were included in this study. Incidence rates of first-ever stroke in each season were estimated using the person-year approach and adjusted for age and sex using the Poisson regression models. RESULTS: From 2011 to 2013, we identified a total of 6,688 stroke cases (3,570 men, 3,118 women), of which 4,480 cases had ischemic stroke (2,518 men, 1,962 women), 1,588 had intracerebral hemorrhage (857 men, 731 women) and 563 had subarachnoid hemorrhage (166 men, 397 women). Age- and sex-adjusted incidence rates of total stroke were 151 (95% confidence interval [CI] 144-160, p = <0.001 vs. summer) in spring, 130 (95% CI 122-137) in summer, 141 (95% CI 133-149, p = 0.020 vs. summer) in autumn and 170 (95% CI 161-179, p = <0.001 vs. summer) in winter. Seasonal variation was more pronounced in intracerebral hemorrhage than in ischemic stroke. CONCLUSION: In the present large-scale stroke registry of general population, incidence rates of stroke were highest in winter and lowest in summer in current Japan.

Molecular Dissection of TDP-43 as a Leading Cause of ALS/FTLD.

TAR DNA binding protein 43 (TDP-43) is a DNA/RNA binding protein involved in pivotal cellular functions, especially in RNA metabolism. Hyperphosphorylated and ubiquitinated TDP-43-positive neuronal cytoplasmic inclusions are identified in the brain and spinal cord in most cases of amyotrophic lateral sclerosis (ALS) and a substantial proportion of frontotemporal lobar degeneration (FTLD) cases. TDP-43 dysfunctions and cytoplasmic aggregation seem to be the central pathogenicity in ALS and FTLD. Therefore, unraveling both the physiological and pathological mechanisms of TDP-43 may enable the exploration of novel therapeutic strategies. This review highlights the current understanding of TDP-43 biology and pathology, describing the cellular processes involved in the pathogeneses of ALS and FTLD, such as post-translational modifications, RNA metabolism, liquid-liquid phase separation, proteolysis, and the potential prion-like propagation propensity of the TDP-43 inclusions.

Transplantation of M2-Deviated Microglia Promotes Recovery of Motor Function after Spinal Cord Injury in Mice.

Despite the poor prognosis of spinal cord injury (SCI), effective treatments are lacking. Diverse factors regulate SCI prognosis. In this regard, microglia play crucial roles depending on their phenotype. The M1 phenotype exacerbates neuroinflammation, whereas the M2 phenotype promotes tissue repair and provides anti-inflammatory effects. Therefore, we compared the effects of M2 and M1 microglia transplantation on SCI. First, we established a method for effective induction of M1 or M2 microglia by exposure to granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin (IL)-4, respectively, to be used for transplantation in a SCI mouse model. In the M2 microglia transplantation group, significant recovery of motor function was observed compared with the control and M1 groups. Elevated transcription of several neuroprotective molecules including mannose receptor C type 1 (Mrc1), arginase 1 (Arg1), and insulin-like growth factor 1 (Igf1) was observed. Moreover, intramuscular injection of FluoroRuby dye revealed recovery of retrograde axonal transport from the neuromuscular junction to upstream of the injured spinal cord only in the M2-transplanted group, although the number of migrated microglia were comparable in both M1 and M2 groups. In conclusion, our results indicated that M2 microglia obtained by IL-4 stimulation may be a promising candidate for cell transplantation therapy for SCI.

Factors Affecting Energy Metabolism and Prognosis in Patients with Amyotrophic Lateral Sclerosis.

BACKGROUND/AIMS: Nutritional status is a factor affecting prognosis in patients with amyotrophic lateral sclerosis (ALS). Here, we aimed to clarify the factors associated with hypermetabolism and the prognosticators of ALS. METHODS: Forty-two inpatients (22 men, 20 women) diagnosed with ALS according to the revised El-Escorial criteria were investigated. The following data were retrospectively analyzed: anthropometric measurements, blood biochemistry, disease severity, basal energy expenditure (BEE), resting energy expenditure (REE) measured by indirect calorimetry, spirometry, and bioelectrical impedance analysis. Single and multiple regression analysis was performed to examine factors affecting REE and metabolic changes (defined as the ratio of REE to fat-free mass [FFM]). The Kaplan-Meier method was used to examine factors associated with the occurrence of cumulative events (death or tracheostomy). RESULTS: Among the 42 inpatients, REE was significantly higher than BEE, indicating hypermetabolism in ALS. Multiple regression analysis revealed that REE/FFM is strongly associated with the skeletal muscle index (-3.746 to -1.532, p < 0.0001) and percent forced vital capacity (%FVC) (-0.172 to -0.021, p = 0.013). Moreover, both the skeletal muscle index and %FVC were significant prognosticators associated with the occurrence of cumulative events. CONCLUSIONS: Energy metabolism was elevated in ALS, and respiratory status and muscle mass were associated with the hypermetabolism and poor prognosis. Adequate nutritional support may improve outcomes in ALS by preventing deterioration of respiratory status and reduction in muscle mass.