Early amyloid-induced changes in microglia gene expression in male APP/PS1 mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia, characterized by deposition of extracellular amyloid-beta (Aß) aggregates and intraneuronal hyperphosphorylated Tau. Many AD risk genes, identified in genome-wide association studies (GWAS), are expressed in microglia, the innate immune cells of the central nervous system. Specific subtypes of microglia emerged in relation to AD pathology, such as disease-associated microglia (DAMs), which increased in number with age in amyloid mouse models and in human AD cases. However, the initial transcriptional changes in these microglia in response to amyloid are still unknown. Here, to determine early changes in microglia gene expression, hippocampal microglia from male APPswe/PS1dE9 (APP/PS1) mice and wild-type littermates were isolated and analyzed by RNA sequencing (RNA-seq). By bulk RNA-seq, transcriptomic changes were detected in hippocampal microglia from 6-months-old APP/PS1 mice. By performing single-cell RNA-seq of CD11c-positive and negative microglia from 6-months-old APP/PS1 mice and analysis of the transcriptional trajectory from homeostatic to CD11c-positive microglia, we identified a set of genes that potentially reflect the initial response of microglia to Aß.

Prevention of microgliosis halts early memory loss in a mouse model of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline, the neuropathological formation of amyloid-beta (Aß) plaques and neurofibrillary tangles. The best cellular correlates of the early cognitive deficits in AD patients are synapse loss and gliosis. In particular, it is unclear whether the activation of microglia (microgliosis) has a neuroprotective or pathological role early in AD. Here we report that microgliosis is an early mediator of synaptic dysfunction and cognitive impairment in APP/PS1 mice, a mouse model of increased amyloidosis. We found that the appearance of microgliosis, synaptic dysfunction and behavioral impairment coincided with increased soluble Aß42 levels, and occurred well before the presence of Aß plaques. Inhibition of microglial activity by treatment with minocycline (MC) reduced gliosis, synaptic deficits and cognitive impairments at early pathological stages and was most effective when provided preventive, i.e., before the onset of microgliosis. Interestingly, soluble Aß levels or Aß plaques deposition were not affected by preventive MC treatment at an early pathological stage (4 months) whereas these were reduced upon treatment at a later stage (6 months). In conclusion, this study demonstrates the importance of early-stage prevention of microgliosis on the development of cognitive impairment in APP/PS1 mice, which might be clinically relevant in preventing memory loss and delaying AD pathogenesis.

LOX-1 mediates inflammatory activation of microglial cells through the p38-MAPK/NF-κB pathways under hypoxic-ischemic conditions.

BACKGROUND: Microglial cells play an important role in the immune system in the brain. Activated microglial cells are not only injurious but also neuroprotective. We confirmed marked lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression in microglial cells in pathological lesions in the neonatal hypoxic-ischemic encephalopathy (nHIE) model brain. LOX-1 is known to be an activator of cytokines and chemokines through intracellular pathways. Here, we investigated a novel role of LOX-1 and the molecular mechanism of LOX-1 gene transcription microglial cells under hypoxic and ischemic conditions. METHODS: We isolated primary rat microglial cells from 3-day-old rat brains and confirmed that the isolated cells showed more than 98% Iba-1 positivity with immunocytochemistry. We treated primary rat microglial cells with oxygen glucose deprivation (OGD) as an in vitro model of nHIE. Then, we evaluated the expression levels of LOX-1, cytokines and chemokines in cells treated with or without siRNA and inhibitors compared with those of cells that did not receive OGD-treatment. To confirm transcription factor binding to the OLR-1 gene promoter under the OGD conditions, we performed a luciferase reporter assay and chromatin immunoprecipitation assay. In addition, we analyzed reactive oxygen species and cell viability. RESULTS: We found that defects in oxygen and nutrition induced LOX-1 expression and led to the production of inflammatory mediators, such as the cytokines IL-1ß, IL-6 and TNF-α; the chemokines CCL2, CCL5 and CCL3; and reactive oxygen/nitrogen species. Then, the LOX-1 signal transduction pathway was blocked by inhibitors, LOX-1 siRNA, the p38-MAPK inhibitor SB203580 and the NF-κB inhibitor BAY11-7082 suppressed the production of inflammatory mediators. We found that NF-κB and HIF-1α bind to the promoter region of the OLR-1 gene. Based on the results of the luciferase reporter assay, NF-κB has strong transcriptional activity. Moreover, we demonstrated that LOX-1 in microglial cells was autonomously overexpressed by positive feedback of the intracellular LOX-1 pathway. CONCLUSION: The hypoxic/ischemic conditions of microglial cells induced LOX-1 expression and activated the immune system. LOX-1 and its related molecules or chemicals may be major therapeutic candidates. Video abstract.

Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1-Related Microglial Activation in Neonatal Hypoxic-Ischemic Encephalopathy: Morphologic Consideration.

Neonatal hypoxic-ischemic encephalopathy (nHIE) is a major neonatal brain injury. Despite therapeutic hypothermia, mortality and sequelae remain severe. The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is associated with the pathophysiology of nHIE. In this study, morphologic change and microglial activation under the nHIE condition and LOX-1 treatment were investigated. The microglial activity and proliferation were assessed with a novel morphologic method, immunostaining, and quantitative PCR in the rat brains of both nHIE model and anti-LOX-1 treatment. Circumference ratio, the long diameter ratio, the cell area ratio, and the roundness of microglia were calculated. The correlation of the morphologic metrics and microglial activation in nHIE model and anti-LOX-1 treated brains was evaluated. LOX-1 was expressed in activated ameboid and round microglia in the nHIE model rat brain. In the evaluation of microglial activation, the novel morphologic metrics correlated with all scales of the nHIE-damaged and treated brains. While the circumference and long diameter ratios had a positive correlation, the cell area ratio and roundness had a negative correlation. Anti-LOX-1 treatment attenuated morphologic microglial activation and proliferation, and suppressed the subsequent production of inflammatory mediators by microglia. In human nHIE, round microglia and endothelial cells expressed LOX-1. The results indicate that LOX-1 regulates microglial activation in nHIE and anti-LOX-1 treatment attenuates brain injury by suppressing microglial activation.

Somatic TARDBP variants as a cause of semantic dementia.

The aetiology of late-onset neurodegenerative diseases is largely unknown. Here we investigated whether de novo somatic variants for semantic dementia can be detected, thereby arguing for a more general role of somatic variants in neurodegenerative disease. Semantic dementia is characterized by a non-familial occurrence, early onset (<65 years), focal temporal atrophy and TDP-43 pathology. To test whether somatic variants in neural progenitor cells during brain development might lead to semantic dementia, we compared deep exome sequencing data of DNA derived from brain and blood of 16 semantic dementia cases. Somatic variants observed in brain tissue and absent in blood were validated using amplicon sequencing and digital PCR. We identified two variants in exon one of the TARDBP gene (L41F and R42H) at low level (1-3%) in cortical regions and in dentate gyrus in two semantic dementia brains, respectively. The pathogenicity of both variants is supported by demonstrating impaired splicing regulation of TDP-43 and by altered subcellular localization of the mutant TDP-43 protein. These findings indicate that somatic variants may cause semantic dementia as a non-hereditary neurodegenerative disease, which might be exemplary for other late-onset neurodegenerative disorders.

Matrin3 binds directly to intronic pyrimidine-rich sequences and controls alternative splicing.

Matrin3 is an RNA-binding protein that is localized in the nuclear matrix. Although various roles in RNA metabolism have been reported for Matrin3, in vivo target RNAs to which Matrin3 binds directly have not been investigated comprehensively so far. Here, we show that Matrin3 binds predominantly to intronic regions of pre-mRNAs. Photoactivatable Ribonucleoside-Enhanced Cross-linking and Immunoprecipitation (PAR-CLIP) analysis using human neuronal cells showed that Matrin3 recognized pyrimidine-rich sequences as binding motifs, including the polypyrimidine tract, a splicing regulatory element. Splicing-sensitive microarray analysis showed that depletion of Matrin3 preferentially increased the inclusion of cassette exons that were adjacent to introns that contained Matrin3-binding sites. We further found that although most of the genes targeted by polypyrimidine tract binding protein 1 (PTBP1) were also bound by Matrin3, Matrin3 could control alternative splicing in a PTBP1-independent manner, at least in part. These findings suggest that Matrin3 is a splicing regulator that targets intronic pyrimidine-rich sequences.

Distinct effects of moisture and air contents on acoustic properties of sandy soil.

Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage.

Multiple exciton generation in cluster-free alloy Cd(x)Hg(1-x)Te colloidal quantum dots synthesized in water.

A number of different composition CdxHg1-xTe alloy quantum dots have been synthesized using a modified aqueous synthesis and ion exchange method. The benefits of good stoichiometric control and high emission quantum yield were retained whilst also ensuring that the tendency to form gel-like clusters and adsorb excess cations in the stabilizing ligand shells was mitigated using a sequestering method to remove excess ionic material during and after the synthesis. This was highly desirable for ultrafast carrier dynamics measurements, avoiding strong photocharging effects which may mask fundamental carrier signals. Transient grating measurements revealed a composition dependent carrier multiplication process which competes with phonon mediated carrier cooling to deplete the initial hot carrier population. The interplay between these two mechanisms is strongly dependent on the electron effective mass which in these alloys has a marked composition dependence and may be considerably lower than the hole effective mass. For a composition x = 0.52 we measured a maximum carrier multiplication quantum yield of 199 ± 19% with pump photon energy 3 times the bandgap energy, Eg, whilst the threshold energy is calculated to be just 2.15Eg. There is some evidence to suggest an impact ionization process analogous to the inverse Auger S mechanism seen in bulk CdxHg1-xTe.

Charge transfer and recombination at the metal oxide/CH3NH3PbClI2/spiro-OMeTAD interfaces: uncovering the detailed mechanism behind high efficiency solar cells.

In recent years, organometal halide perovskite-based solid-state hybrid solar cells have attracted unexpected increasing interest because of their high efficiency (the record power conversion efficiency has been reported to be over 15%) and low fabrication cost. It has been accepted that the high efficiency was mainly attributed to the strong optical absorption (absorption coefficient: 15,000 cm(-1) at 550 nm) over a broader range (up to 800 nm) and the long lifetimes of photoexcited charge carriers (in the order of 10 ns - a few 100 ns) of the perovskite absorbers. However, much of the fundamental photophysical properties of perovskite relating to the high photovoltaic performance are remained to be investigated. The charge separation and recombination processes at the material interfaces are particularly important for solar cell performances. To better understand the high efficiency of perovskite solar cells, we systematically investigated the charge separation (electron and hole injection) and charge recombination dynamics of CH3NH3PbClI2 hybrid solar cells employing TiO2 nanostructures as the electron transfer material (ETM) and spiro-OMeTAD as the hole transfer material (HTM). The measurements were carried out using transient absorption (TA) techniques on a time scale from sub-picoseconds to milliseconds. We clarified the timescales of electron injection, hole injection, and recombination processes in TiO2/CH3NH3PbClI2/spiro-OMeTAD solar cells. Charge separation and collection efficiency of the perovskite-based solar cells were discussed. In addition, the effect of TiO2 size on the charge separation and recombination dynamics was also investigated. It was found that all TiO2-based perovskite solar cells possessed similar charge separation processes, but quite different recombination dynamics. Our results indicate that charge recombination was crucial to the performance of the perovskite solar cells, which could be effectively suppressed through optimising nanostructured TiO2 films and surface passivation, thus pushing these cells to even higher efficiency.

Three-dimensional urban acoustic simulations and scale-model measurements over real-life topography.

Comparisons of finite-difference time-domain sound propagation simulations over real-life urban topography with scale-model experimental measurements are performed. A 1:100 scale model for the measurements and full-scale input geometry for the simulations are created by using digital geographic datasets. The sound pressure levels obtained by the measurements and simulations resulted in approximately 2 dB of root mean square error in the 125 and 250 Hz octave bands, and 4 dB in 500 Hz. Visualizations of a low-frequency sound propagation case by the measurement and simulation clearly show the wave phenomena caused by buildings and natural terrain.

Radiotherapy induces persistent innate immune reprogramming of microglia into a primed state.

Over half of patients with brain tumors experience debilitating and often progressive cognitive decline after radiotherapy treatment. Microglia, the resident macrophages in the brain, have been implicated in this decline. In response to various insults, microglia can develop innate immune memory (IIM), which can either enhance (priming or training) or repress (tolerance) the response to subsequent inflammatory challenges. Here, we investigate whether radiation affects the IIM of microglia by irradiating the brains of rats and later exposing them to a secondary inflammatory stimulus. Comparative transcriptomic profiling and protein validation of microglia isolated from irradiated rats show a stronger immune response to a secondary inflammatory insult, demonstrating that radiation can lead to long-lasting molecular reprogramming of microglia. Transcriptomic analysis of postmortem normal-appearing non-tumor brain tissue of patients with glioblastoma indicates that radiation-induced microglial priming is likely conserved in humans. Targeting microglial priming or avoiding further inflammatory insults could decrease radiotherapy-induced neurotoxicity.

Degenerative spondylolisthesis does not influence surgical results of laminoplasty in elderly cervical spondylotic myelopathy patients.

The objective of the study was to investigate the comorbidity of degenerative spondylolisthesis (DS), in elderly cervical spondylotic myelopathy (CSM) patients in our hospital, and the correlation between surgical results and preoperative DS. There are few studies on the outcome of laminoplasty for CSM with DS. A total of 49 elderly patients (>65 years old) who eventually had surgical treatment for CSM were evaluated. A slippage displacement of more than 2.5 mm at least at one level was classified to have a positive DS on flexion/extension radiographs (DS group). A slippage displacement less than 1.0 mm was considered a negative DS (non-DS group). Seventeen patients who had slippage of 1.0-2.5 mm were excluded from the study. The DS group (n = 15) included cases with DS at preoperation, while the remaining cases (n = 17) belonged to the non-DS group. The flexion/extension radiographs of the two groups were compared for range of motion and clinical results at 3 years after the operation. Of all elderly patients, 30.6% had DS. There was no significant difference between the two groups based on the clinical results. The range of motion of all cervical spines (DS group and non-DS group) was significantly limited. However, there was no significant difference between the two groups. New postoperative DS appeared in four patients, of which two were from the DS group and two from the non-DS group. These data suggest that degenerative spondylolisthesis does not influence surgical results in elderly cervical spondylotic myelopathy patients.

THETA system allows one-step isolation of tagged proteins through temperature-dependent protein-peptide interaction.

Tools to control protein-protein interactions by external stimuli have been extensively developed. For this purpose, thermal stimulation can be utilized in addition to light. In this study, we identify a monoclonal antibody termed C13 mAb, which shows an approximately 480-fold decrease in the affinity constant at 37 °C compared to that at 4 °C. Next, we apply this temperature-dependent protein-peptide interaction for one-step protein purifications. We term this THermal-Elution-based TAg system as the THETA system, in which gel-immobilized C13 mAb-derived single-chain variable fragment (scFv) (termed THETAL) is able to bind with proteins tagged by C13 mAb-epitope(s) (THETAS) at 4 °C and thermally release at 37-42 °C. Moreover, to reveal the temperature-dependent interaction mechanism, molecular dynamics simulations are performed along with epitope mapping experiments. Overall, the high specificity and reversibility of the temperature-dependent features of the THETA system will support a wide variety of future applications such as thermogenetics.

Does developmental canal stenosis influence surgical results of bilateral open-door laminoplasty for cervical spondylotic myelopathy?

OBJECT: The purpose of this study was to investigate the prevalence of developmental canal stenosis in patients with cervical spondylotic myelopathy (CSM), and the correlation between surgical results and degree of developmental canal stenosis. METHODS: A total of 112 patients who eventually had surgical treatment for CSM were evaluated. Male patients whose sagittal spinal diameter was < 14 mm and females whose sagittal diameter was < 13 mm even at one level were classified as having developmental canal stenosis. Two groups of patients were used in this study; the "positive" group (57 cases) included patients with developmental canal stenosis preoperatively, whereas the "negative" group (55 cases) excluded such patients. Lateral functional radiographs obtained in patients in the 2 groups were compared for range of motion and clinical results. RESULTS: Developmental canal stenosis was found in 50.9% of all cases. Based on clinical results, there was no significant difference between the 2 groups. CONCLUSIONS: Patients with CSM showed a high incidence of preoperative developmental canal stenosis. However, there were no significant differences in clinical results between patients with and without this disorder. These results indicate that developmental canal stenosis is not a factor that influences surgical results.

Quantification of methylation efficiency at a specific N6-methyladenosine position in rRNA by using BNA probes.

We found that insertion of artificial nucleic acid analogs, such as bridged nucleic acid (BNA), into DNA probes increases the difference in melting temperature between N6-methyladenosine (m6A)-containing RNA and unmethylated RNA. By applying this principle, we quantified methylation efficiency at m6A sites in E. coli 23S rRNA with high accuracy.

Magnification error in digital radiographs of the cervical spine against magnetic resonance imaging measurements.

STUDY DESIGN: Prospective study. PURPOSE: The main purpose of this study was to clarify the range of magnification errors on digital plain radiographs and to determine if there is a correlation between the body mass index (BMI) of a patient and the magnification error. OVERVIEW OF LITERATURE: Most clinicians currently use digital plain radiography. This new method allows one to access images and measure lengths and angles more easily than with the past technologies. In addition, conventional plain radiography has magnification errors. Although few articles mention magnification errors in regards to digital radiographs, they are known to have the same errors. METHODS: We used plain digital radiography and magnetic resonance imaging (MRI) to acquire images of the cervical spine with the goal of evaluating magnification errors by measuring the anteroposterior vertebral body lengths of C2 and C5. The magnification error (ME) was then calculated: ME=(length on radiograph-length on MRI)/length on MRI ×100 (%). The correlation coefficient between the magnification error and BMI was obtained using Pearson's correlation analysis. RESULTS: Average magnification errors in C2 and C5 were approximately 18.5%±5.4% (range, 0%-30%) and 20.7%±6.3% (range, 1%-32%). There was no positive correlation between BMI and the magnification error. CONCLUSIONS: There were magnification errors on the digital plain radiographs, and they were different in each case. Maximum magnification error differences were 30% (C2) and 31% (C5). Based on these finding, clinicians must pay attention to magnification errors when measuring lengths using digital plain radiography.

Temporal changes in the tensile strength of ultra-high-molecular-weight polyethylene cable embedded in muscle tissue.

BACKGROUND: Wires and cables have been used extensively for spinal sublaminar wiring, but damages to the spinal cord due to compression by metal wires have been reported. We have used more flexible ultra-high-molecular-weight polyethylene cable (Tekmilon tape) instead of metal wires since 1999 and have obtained good clinical outcomes. Although the initial strength of Tekmilon tape is equivalent to metal wires, the temporal changes in the strength of Tekmilon tape in the body should be investigated to show that sufficient strength is maintained over time until bone union is complete. METHODS: Tekmilon tape was embedded into the paravertebral muscle of 10-week-old male Japanese white rabbits. Samples were embedded for 0, 1, 3, 6 or 12 months. At the end of each period, sequential straight tensile strength and sequential knot-pull tensile strength were measured. FINDINGS: The initial strength of Tekmilon tape in muscle tissue was maintained over time, with 92% straight tensile strength and 104% knot-pull tensile strength at 6months, and values of 77% and 100% at 12 months, respectively. Since single knot is clinically relevant, it is very important that the knot-pull tensile strength did not decrease over a 12-month period. This suggests that temporal changes in the tensile strength of Tekmilon tape are negligible at 1 year. INTERPRETATION: Tekmilon tape maintains sufficient strength in vivo until bone union has occurred. It is useful for sublaminar wiring instead of metal materials due to its flexibility and strength and may reduce the risk of neurological damage.