Publications by authors named "Kosuke Yamaguchi"

Posttranslational modifications (PTMs) of proteins are efficient biological mechanisms for expanding the genetic code and for regulating cellular physiology. However, there have been no systematic approaches to profile all the PTMs critical for autoreactive neoantigen production or the etiology and pathology of autoimmune diseases. In the present study, to gain insight into protein PTMs associated with systemic lupus erythematosus (SLE), we applied a mass spectrometry-based method for the comprehensive analysis of modified amino acids ("adductome").

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Persistent SARS-CoV-2 infections involve prolonged viral replication and immune system interactions, potentially driving viral evolution and immune escape. This study examines viral characteristics and host gene expression changes in persistent infections. The nasopharyngeal samples from four patients with persistent SARS-CoV-2 infections at Tottori University Hospital, Japan, were analyzed.

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Inhibitors of DNA methylation such as 5-aza-deoxycytidine are widely used in experimental and clinical settings. However, their mechanism of action is such that DNA damage inevitably co-occurs with loss of DNA methylation, making it challenging to discern their respective effects. Here we deconvolute the effects of decreased DNA methylation and DNA damage on cancer cells, by using degron alleles of key DNA methylation regulators.

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UL16-binding protein 2 (ULBP2), a ligand for the activating receptor NKG2D, plays a dual role in tumor immunity, promoting immune activation or suppression, depending on the context. To investigate its impact on CD4CD25 T cell-targeted immunotherapies, we used a syngeneic CT26 colon cancer model engineered to express ULBP2 and compared tumor growth and tumor-infiltrating lymphocyte (TIL) profiles in control and ULBP2-expressing tumors treated with anti-CD4, anti-CD25, or anti-CTLA-4 antibodies. Tumor growth was uniformly assessed on day 21 post-transplantation, and TIL analysis was performed in groups with evaluable residual tumors.

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Background: The SARS-CoV-2 Omicron variant is associated with milder COVID-19 symptoms than previous strains. This study analyzed alterations in natural killer (NK) cell-associated immunity dynamics in mild and moderate COVID-19 cases during the Omicron phase of the COVID-19 pandemic.

Methods: We conducted a retrospective observational cohort study of patients aged ≥16 with confirmed SARS-CoV-2 infection who were hospitalized at Tottori University Hospital between January 2022 and May 2022.

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UL-16 binding protein 2 (ULBP2), a human NKG2D ligand, has been identified as a poor prognostic factor in several cancers based on recent comprehensive analyses of immune-related genes using the Cancer Genome Atlas datasets. Despite its clinical significance, the functional role of ULBP2 in vivo remains largely unknown. In this study, we investigated the role of ULBP2 in modulating anti-tumor immunity using murine melanoma cell lines engineered to stably express surface-expressed or soluble ULBP2.

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Currently, immune checkpoint inhibitors (ICIs) are the standard treatment for malignant pleural mesothelioma (MPM). The characteristic responses to ICI treatment include pseudoprogression (PP) and hyperprogressive disease (HPD), which require attention. Reports on PP of MPM are rare.

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Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are highly effective against EGFR-mutant non-small-cell lung carcinoma but can cause serious adverse events, such as interstitial lung disease (ILD). Treatment strategies for osimertinib-induced ILD are not well established. Cytotoxic anticancer drugs are considered first, although several cases of successful rechallenge with EGFR-TKIs have been reported.

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Asthma is characterized by chronic airway inflammation as its primary pathological condition, which leads to various respiratory symptoms due to airway narrowing, with type 2 inflammation playing a central role. Asthma treatment, primarily centered on inhaled corticosteroids, aims to suppress type 2 inflammation and improve airway narrowing. However, severe asthma that cannot be controlled with high-dose inhaled corticosteroids or other asthma medications remains a clinical issue.

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We take a wide variety of antioxidants, including polyphenols, daily from our diet. They are generally considered to be beneficial for our health. However, the intrinsic function of antioxidants in biological systems remain unknown.

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Steroidogenesis occurs locally in peripheral tissues and via adrenal and gonadal glands' biosynthesis. The C2C12 mouse myoblast cell line and rat skeletal muscles harbor a local steroidogenesis pathway for glucocorticoids, and corticosterone is biosynthesized from skeletal muscle cells. However, Cyp11a1 and StAR protein expressions are not observed in C2C12 cells or rat muscular tissues.

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Pembrolizumab is an anti-programmed cell death-1 (PD-1) antibody used to treat various cancer types. Treatments with such immune checkpoint inhibitors cause immune-related adverse events. However, airway inflammation caused by immune-related adverse events has rarely been reported.

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DNA methylation is an essential epigenetic chromatin modification, and its maintenance in mammals requires the protein UHRF1. It is yet unclear if UHRF1 functions solely by stimulating DNA methylation maintenance by DNMT1, or if it has important additional functions. Using degron alleles, we show that UHRF1 depletion causes a much greater loss of DNA methylation than DNMT1 depletion.

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Anti-DNA antibodies (Abs), serological hallmarks of systemic lupus erythematosus (SLE) and markers for diagnosis and disease activity, show a specificity for non-nucleic acid molecules, such as N-pyrrolated proteins (pyrP) containing N-pyrrole-L-lysine (pyrK) residues. However, the detailed mechanism for the binding of anti-DNA Abs to pyrP remains unknown. In the present study, to gain structural insights into the dual-specificity of anti-DNA Abs, we used phage display to obtain DNA-binding, single-chain variable fragments (scFvs) from SLE-prone mice and found that they also cross-reacted with pyrP.

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Epigenetic mechanisms are essential to establish and safeguard cellular identities in mammals. They dynamically regulate the expression of genes, transposable elements and higher-order chromatin structures. Consequently, these chromatin marks are indispensable for mammalian development and alterations often lead to disease, such as cancer.

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In mammals, only the zygote and blastomeres of the early embryo are totipotent. This totipotency is mirrored in vitro by mouse '2-cell-like cells' (2CLCs), which appear at low frequency in cultures of embryonic stem cells (ESCs). Because totipotency is not completely understood, we carried out a genome-wide CRISPR knockout screen in mouse ESCs, searching for mutants that reactivate the expression of Dazl, a gene expressed in 2CLCs.

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Spermatozoa have a unique genome organization. Their chromatin is almost completely devoid of histones and is formed instead of protamines, which confer a high level of compaction and preserve paternal genome integrity until fertilization. Histone-to-protamine transition takes place in spermatids and is indispensable for the production of functional sperm.

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Article Synopsis
  • DNMT1 is a crucial enzyme for maintaining DNA methylation, but its activation mechanisms are not fully known.
  • Researchers used cryo-electron microscopy to reveal the structure of DNMT1 when bound to hemimethylated DNA and ubiquitinated histone H3, identifying a key linker that aids in its activation.
  • The study highlights how the linker helps shift the enzyme from an inactive to an active state, offering new insights for research and potential drug development targeting DNMT1.
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Sperm chromatin compaction is physiologically essential for sperm to acquire the fertility. However, this unique structure composed of protamines makes us unable to solubilize the chromatin due to its resistance to sonication and enzymes usually used for chromatin fragmentation in somatic cells. Even when intense enzymatic treatment is applied, it appears to solubilize only certain portions of sperm chromatin presumably because of the heterogeneous properties.

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Antioxidants are sensitive to oxidation and are immediately converted into their oxidized forms that can react with proteins. We have recently found that proteins incubated with oxidized vitamin C (dehydroascorbate) gain a new function as a histone-binding ligand. This finding led us to predict that antioxidants, through conversion to their oxidized forms, may generally have similar functions.

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Aseptic meningitis is a rare immune-related adverse event (irAE), which occurs during treatment with immune checkpoint inhibitors (ICIs). This condition has non-specific symptoms and exhibits no clear signs on magnetic resonance imaging (MRI). There are only a few reports of aseptic meningitis caused by pembrolizumab treatment for non-small cell lung cancer (NSCLC).

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Article Synopsis
  • Epigenetic abnormalities are prevalent in cancer, influencing both the onset and progression of the disease, and serve as potential biomarkers and therapeutic targets.
  • The review focuses on large-scale chromatin changes that lead to significant modifications in DNA methylation and histone patterns, examining how factors like mutations, metabolism, and infections can disrupt the normal epigenome.
  • It highlights the implications of these epigenetic alterations for cancer therapies and emphasizes the importance of single-cell approaches in advancing our understanding of the field.
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Reducing sugars can covalently react with proteins to generate a heterogeneous and complex group of compounds called advanced glycation end products (AGEs). AGEs are generally considered as pathogenic molecules, mediating a pro-inflammatory response and contributing to the development of a number of human diseases. However, the intrinsic function of AGEs remains to be elucidated.

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Olefin production from polyols via deoxydehydration (DODH) was carried out over Ag-modified CeO -supported heterogeneous Re catalysts with H as a reducing agent. Both high DODH activity and low hydrogenation ability for C=C bonds were observed in the reaction of erythritol, giving a 1,3-butadiene yield of up to 90 % under "solvent-free" conditions. This catalyst is applicable to other substrates such as methyl glycosides (methyl α-fucopyranoside: 91 % yield of DODH product; methyl β-ribofuranoside: 88 % yield), which were difficult to be converted to the DODH products over the DODH catalysts reported previously.

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Lysine N-pyrrolation, a posttranslational modification, which converts lysine residues to N-pyrrole-L-lysine, imparts electronegative properties to proteins, causing them to mimic DNA. Apolipoprotein E (apoE) has been identified as a soluble receptor for pyrrolated proteins (pyrP), and accelerated lysine N-pyrrolation has been observed in apoE-deficient (apoE) hyperlipidemic mice. However, the impact of pyrP accumulation consequent to apoE deficiency on the innate immune response remains unclear.

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