Publications by authors named "Yasuhiro Kojima"

Messenger RNA splicing and degradation are critical for gene expression regulation, the abnormality of which leads to diseases. Previous methods for estimating kinetic rates have limitations, assuming uniform rates across cells. DeepKINET is a deep generative model that estimates splicing and degradation rates at single-cell resolution from scRNA-seq data.

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Motivation: Single-cell RNA sequencing (scRNA-seq) enables comprehensive characterization of the cell state. However, its destructive nature prohibits measuring gene expression changes during dynamic processes such as embryogenesis or cell state divergence due to injury or disease. Although recent studies integrating scRNA-seq with lineage tracing have provided clonal insights between progenitor and mature cells, challenges remain.

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  • The study investigates cell-cell interactions in colorectal cancer (CRC) to understand how adenomas progress to sporadic CRC, aiming to improve patient survival rates.
  • By using spatial transcriptomics on early and advanced CRC cases, the researchers identified key interactions between cancer cells and regulatory T cells (Tregs) that may lead to immune suppression in the tumor microenvironment.
  • Findings highlight midkine (MDK) as a critical signaling molecule involved in these interactions and indicate that higher MDK/SDC4 levels are linked to poorer survival outcomes in CRC patients, suggesting a potential target for early diagnosis and treatment.
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  • Understanding how different cell types interact is crucial for studying diseases, but current computational methods may overlook important molecular signals during these interactions.
  • DeepCOLOR is a new advanced framework that uses deep learning to analyze cell interactions at a single-cell level by combining single-cell data with spatial information.
  • It has shown improved accuracy in identifying cell interactions in various biological samples, including mouse brains and human cancer and COVID-19 tissues, allowing for deeper insights into cell communication in different environments.
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Single-cell RNA-seq analysis coupled with CRISPR-based perturbation has enabled the inference of gene regulatory networks with causal relationships. However, a snapshot of single-cell CRISPR data may not lead to an accurate inference, since a gene knockout can influence multi-layered downstream over time. Here, we developed RENGE, a computational method that infers gene regulatory networks using a time-series single-cell CRISPR dataset.

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Bone marrow-derived cells (BMDCs) infiltrate hypoxic tumors at a pre-angiogenic state and differentiate into mature macrophages, thereby inducing pro-tumorigenic immunity. A critical factor regulating this differentiation is activation of SREBP2-a well-known transcription factor participating in tumorigenesis progression-through unknown cellular mechanisms. Here, we show that hypoxia-induced Golgi disassembly and Golgi-ER fusion in monocytic myeloid cells result in nuclear translocation and activation of SREBP2 in a SCAP-independent manner.

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  • Embryonic development is a structured series of changes in cell states influenced by complex molecular processes, as studied in zebrafish tailbud using advanced techniques like RNA sequencing and cell tracking.
  • Researchers identified and mapped cell expression and motion states across embryos, revealing consistent patterns over time despite individual variations.
  • These variations lead to left-right asymmetries, suggesting that collective cell movement can create differences rather than simply smooth out the randomness of individual cells.
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The presence of some amino acid mutations in the amino acid sequence that determines a protein's structure can significantly affect that 3D structure and its biological function. However, the effects upon structural and functional changes differ for each displaced amino acid, and it is very difficult to predict these changes in advance. Although computer simulations are very effective at predicting conformational changes, they struggle to determine whether the amino acid mutation of interest induces sufficient conformational changes, unless the researcher is a specialist in molecular structure calculations.

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  • The study explores how cellular interactions in the tumor microenvironment affect treatment strategies for colorectal cancer (CRC), focusing on the invasion front of tumors.
  • By combining spatial transcriptomics and a single-cell transcriptomic atlas, researchers analyze CRC tissues to better understand cell-to-cell communication in this critical area.
  • The findings reveal that CRC cells at the invasion front can influence macrophages and enhance both their own growth and invasiveness while simultaneously evading anti-tumor immunity.
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  • IBD patients have lower immunity levels against certain viruses (measles, rubella, mumps, varicella) compared to healthy control subjects, indicating a potential risk when starting immunosuppressive therapy.
  • The study included 437 IBD patients (with ulcerative colitis and Crohn's disease) and 225 healthy individuals, finding significant differences in seropositivity, particularly for patients with ulcerative colitis.
  • Screening for immunity to these viruses in IBD patients is recommended before they begin immunosuppressive treatment to prevent potential complications.
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  • - The traditional view of hematopoiesis as a stepwise process has shifted to a continuous one due to advancements in single-cell RNA sequencing, which revealed complexities in the differentiation process that weren’t previously acknowledged.
  • - This study focuses on the B-plasmacytoid dendritic cell (pDC) pathway, identifying significant fluctuations in transcriptome dynamics in the B/NK progenitor region using novel computational methods that model splicing kinetics.
  • - The findings illustrate that these fluctuations are critical for differentiation, demonstrating a model that reconciles continuous and discrete processes, with implications for understanding other developmental systems.
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  • A clinical trial was conducted to test the efficacy and safety of ultrahigh-dose methylcobalamin in patients with ALS diagnosed within a year of onset, indicating a need for better treatments given the limited effectiveness of current drugs.
  • The study was multicenter, double-blind, and placebo-controlled, enrolling 130 patients from Japan, who received either the methylcobalamin treatment or a placebo for 16 weeks.
  • The main outcome measured was the change in the Revised ALS Functional Rating Scale score, with results showing a significant number of patients observed completing the trial, highlighting the continued investigation into the drug's potential benefits for ALS.
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  • Immune checkpoint blockade (ICB) shows promise in treating cancer, but its effectiveness is limited by the presence of immunosuppressive cells, particularly regulatory T cells (Tregs) in the tumor environment.
  • A selective PI3K inhibitor, ZSTK474, was tested in combination with PD-1 blockade to evaluate its impact on Tregs and CD8 T cells in both animal models and human samples.
  • Results indicated that while higher doses of the PI3K inhibitor can impair CD8 T cell activation, careful optimization of dosage can selectively decrease Tregs, enhance CD8 T cell responses, and contribute to long-lasting antitumor immunity.
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  • - The study introduces algorithms that estimate the evolutionary time since the last substitution event in genomic sequences, utilizing a probabilistic model to improve accuracy based on alignment patterns and gap fractions.
  • - Researchers identified human genomic sites where substitutions occurred around key speciation events, particularly noting a significant concentration of these substitutions associated with brain-specific enhancers.
  • - The new algorithms enhance the understanding of evolutionary development (Evo-Devo) by helping to identify important genomic sites that may be responsible for unique biological traits in various species.
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  • Researchers developed advanced tools to study ultrafast surface plasmon polariton (SPP) pulses, which occur on extremely short timescales and small distances.
  • They created two types of scanning near-field optical microscopes (SNOMs) and employed spectral interferometry to accurately measure these rapid SPP pulses.
  • Using these techniques, they were able to analyze the plasmonic behavior of gold nanorods on a GeSbTe thin film in both crystalline and amorphous states, and successfully captured the temporal profile of SPP pulses on a gold layer.
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Motivation: Evolve and resequence (E&R) experiments show promise in capturing real-time evolution at genome-wide scales, enabling the assessment of allele frequency changes SNPs in evolving populations and thus the estimation of population genetic parameters in the Wright-Fisher model (WF) that quantify the selection on SNPs. Currently, these analyses face two key difficulties: the numerous SNPs in E&R data and the frequent unreliability of estimates. Hence, a methodology for efficiently estimating WF parameters is needed to understand the evolutionary processes that shape genomes.

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Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the upper and lower motor neurons. Currently, only riluzole and edaravone are approved as drugs to treat ALS and new agents with larger effect sizes are warranted. Exploratory analyses in our previous study (study ID #E0302-J081-761) have suggested that high-dose methylcobalamin (E0302) prolonged the overall survival of ALS patients and suppressed ALS progression in patients with a disease duration of less than 12 months.

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Recapitulative animal models of idiopathic pulmonary fibrosis (IPF) and related diseases are lacking, which inhibits our ability to fully clarify the pathogenesis of these diseases. Although lung fibrosis in mouse models is often induced by bleomycin, silica-induced lung fibrosis is more sustainable and more progressive. Therefore, in this study, we sought to elucidate the mediator(s) responsible for the pathogenesis of lung fibrosis, through the use of a mouse model of silica-induced lung fibrosis.

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  • - The study explores ultrafast surface plasmon polariton (SPP) nanofocusing using femtosecond laser pulses on a tapered aluminum tip, allowing for localized excitation beyond the diffraction limit through a novel method.
  • - By using dual wavelengths of 440 nm and 800 nm in a coherent anti-Stokes Raman scattering (CARS) microscopy technique, the researchers achieved significantly increased Raman intensity for monolayer graphene, improving detection capabilities.
  • - The new imaging approach was successfully applied to multiwalled carbon nanotubes, and the findings suggest potential for advancements in nanoscale microspectroscopy and various optical excitation techniques.
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  • A 24-year-old woman experienced unsteadiness in her gait, with neurological exams revealing mild dysmetria in her limbs and difficulty with balance and coordination.
  • MRI scans indicated Lhermitte-Duclos disease, which is associated with an enlarged left cerebellar hemisphere and is linked to the inherited condition Cowden syndrome.
  • Cowden syndrome is characterized by various benign tumors (hamartomas) and a mutation in the PTEN gene, and requires careful monitoring due to the increased risk of malignancies from these tumors.
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Background: Viral infections are the most common triggers of asthma exacerbation, but the key molecules involved in this process have not been fully identified. Although cysteinyl leukotrienes (cysLTs) have been postulated as the key mediators, their precise roles remain largely unclear. To investigate the roles of cysLTs in virus-induced asthma exacerbation, we developed a murine model using a viral double-stranded RNA analog, polyinosinic-polycytidylic acid (poly I:C), and analyzed the effect of leukotriene receptor antagonist (LTRA) administration.

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  • Fibrinogen replacement therapy helps control bleeding and reduce blood transfusions during critical situations, specifically in thoracic aortic surgery.
  • A study of 169 patients found that those who received cryoprecipitate or fibrinogen concentrate experienced significantly less postoperative bleeding and required fewer blood transfusions, especially when their fibrinogen levels were low.
  • The effective dose for patients is determined to be between 2-3 grams for those weighing 50-70 kg, with optimal benefits when fibrinogen levels are below 130 mg/dL during surgery.
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Objective: This paper reports a patient with bulbospinal muscular atrophy (BSMA) who presented with spinal myoclonus, documented by video and surface electromyography.

Case Report: A 66-year-old man had progressive gait disturbance, dysphagia, and easy fatigability of all extremities over a period of 4 years. Neurologically, muscle atrophy, fasciculation, and weakness were observed in the bulbar and limb muscles.

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The total synthesis of KB-3346-5A, named naphthacemycin A, has been accomplished by combining the Dötz reaction and Suzuki-Miyaura cross coupling as well as employing Friedel-Crafts reaction with dienone-phenol rearrangement as key steps. We also describe the preparation of the simplified tetarimycin A and naphthacemycin A analogs as a model study, which coincidentally reveal unique properties of naturally occurring naphthacene-5,6,11(12H)-trione framework. The synthesized compounds were evaluated for antibacterial activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus (VRE) to elucidate their structure-activity relationships (SARs), the results of which agreed with a previously reported preliminary SAR study of tetarimycin A.

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  • The flexor carpi radialis brevis (FCRB) is an unusual muscle-tendon structure found in the wrist.
  • This report discusses five specific cases of FCRB identified among 123 patients who underwent surgery for distal radius fractures.
  • The fractures were treated using volar locking plates, which is a common surgical method.
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