Publications by authors named "Hiroto Takeuchi"

Background: Memory CD8 T cells sense inflammation and rapidly produce interferon-γ (IFN-γ) independent of cognate antigens. This innate-like property, called bystander activation, is involved in early host defense before the antigen-specific memory response. However, the molecular mechanisms underlying this activation remain unknown.

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Background: This study evaluated the effects of difelikefalin, a kappa opioid receptor (KOR) agonist, on the inflammatory response and renal dysfunction in a rat model of acute kidney injury induced by renal ischemia-reperfusion injury, comparing it with other KOR agonists.

Methods: One week after right nephrectomy, rats received one of three drugs (difelikefalin, nalfurafine hydrochloride, or U-50488H). Thirty minutes later, ischemia was induced in the left kidney by clamping its artery and vein for 45 min.

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Antibody-dependent enhancement (ADE) is one of the mechanisms associated with severe clinical outcomes in infections caused by certain viruses, including dengue virus (DENV). Several ADE assay systems have been established, including flow cytometric assays using live viruses, enzyme-linked immuno-sorbent assay (ELISA) for the detection of viral NS1, and luciferase reporter gene assays. Among these, the flow cytometric assay is the most commonly used to evaluate ADE activity; however, it has limitations such as high operational costs due to fixation and immunostaining procedures, as well as a long analysis time.

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Immune checkpoint inhibitors (ICIs) are widely used for cancer immunotherapy; however, the clinical efficacy of anti-PD-1/PD-L1 monotherapy is generally limited, highlighting the need to develop combination therapies. Dogs develop spontaneous tumors in immunocompetent settings, and anti-PD-1/PD-L1 antibodies exert similar clinical benefits. However, no clinically relevant anti-CTLA-4 antibody has been reported, limiting the value of canine tumors as comparative models for human ICI research.

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The tumor suppressor p53 activates transcription of the IER5 gene, which encodes an adapter protein of protein phosphatase PP2A. IER5 binds to both the B55 regulatory subunit of PP2A and PP2A's target proteins, facilitating PP2A/B55-catalyzed dephosphorylation of these proteins. Here, we show that IER5 functions as a positive regulator of p53 by inhibiting its ubiquitination, thereby increasing cellular p53 levels.

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Titanium dioxide doped with Pt(IV) ions was synthesized via a sol-gel method, incorporating a sol purification process through dialysis. The doped Pt(IV) ions were reduced by UV light irradiation to obtain a transparent Pt-TiO sol, with Pt(0) acting as a cocatalyst for hydrogen evolution. The hydrogen evolution activity of Pt-TiO sol was evaluated under UV light irradiation using methanol as a sacrificial reagent.

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Article Synopsis
  • Immune checkpoint inhibitors (ICIs), specifically c4G12, show promise in treating various advanced malignant tumors in dogs, including osteosarcoma and nasal adenocarcinoma, based on a clinical study conducted at Hokkaido University.
  • The study involved 12 dogs, with a treatment regimen of c4G12 administered bi-weekly, revealing a significant incidence of treatment-related adverse effects in 8 dogs, though most were manageable.
  • The results indicate a 25% objective response rate among dogs with measurable disease, highlighting the need for further research to better understand which tumor types respond best to this treatment.
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The transcription factor E2F1 participates in cell cycle control through transcriptional activation of genes that promote S-phase entry. E2F1 is also linked to the expression of proapoptotic genes, and the loss of E2F1 activity facilitates tumor progression by reducing cellular apoptosis. Phosphorylation controlled by protein kinases and phosphatases is the major posttranslational modification and regulates the cellular levels and transactivator function of E2F1.

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Article Synopsis
  • Immune checkpoint inhibitors (ICIs), like the anti-PD-L1 antibody, have shown limited effectiveness in treating canine malignant melanoma.
  • Recent research on humans indicates that combining radiation therapy (RT) with ICIs can enhance systemic antitumor immunity.
  • This study found that hypofractionated RT followed by anti-PD-L1 therapy showed improved clinical benefits and overall survival in dogs, particularly for those who had previous RT, suggesting this combination might be a promising treatment strategy with manageable side effects.
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  • Coagulase-positive Staphylococci, like Staphylococcus aureus, use a protein called protein A (SpA) to evade the immune system, but SpA only effectively binds to one of four canine IgG subclasses (IgG-B), making purification of other subclasses difficult.
  • Researchers hypothesized that SpsQ, a protein from Staphylococcus pseudintermedius, would bind more effectively to canine IgGs, providing a better option for purifying therapeutic antibodies.
  • Tests revealed that SpsQ binds strongly to IgG-A and IgG-D compared to SpA, and affinity chromatography using SpsQ led to higher recovery rates for these subclasses, suggesting SpsQ is a promising alternative ligand for canine
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Spontaneous tumors are a major cause of death in cats. Treatment of human tumors has progressed dramatically in the past decade, partly due to the success of immunotherapies using immune checkpoint inhibitors, such as anti-programmed death 1 (PD-1) and anti-PD-ligand 1 (PD-L1) antibodies. However, little is known about the PD-1 pathway and its association with tumor disease in cats.

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The retinoblastoma (RB) tumour suppressor protein regulates cell proliferation, motility, differentiation and apoptosis. The phosphorylation state of RB is modulated by kinases and phosphatases, and RB exhibits phosphorylation-sensitive interactions with E2F family transcription factors. Here, we characterize RB dephosphorylation by protein phosphatase 2A (PP2A).

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Immune checkpoint inhibitors (ICIs) such as anti-PD-L1 antibodies are widely used to treat human cancers, and growing evidence suggests that ICIs are promising treatments for canine malignancies. However, only some canine oral malignant melanoma (OMM) cases respond to ICIs. To explore biomarkers predictive of survival in dogs with pulmonary metastatic OMM receiving the anti-PD-L1 antibody c4G12 (n = 27), serum concentrations of prostaglandin E2 (PGE), cytokines, chemokines, and growth factors were measured prior to treatment initiation.

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Previously it was shown that cisplatin causes muscle atrophy. Under this condition, cisplatin increased the expression of atorogenes, such as muscle ring finger 1 and atrogin-1 (also known as muscle atrophy F-box protein), in mouse skeletal muscle. It was reported recently that ubiquitin (Ub) and ubiquitinated protein levels in skeletal muscle were also up-regulated in cisplatin-induced muscle atrophy, and cisplatin-induced ubiquitinated proteins were degraded by the 26S proteasome pathway.

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Cancer cells can evade host immune systems multiple mechanisms. Transforming growth factor beta 1 (TGF-β1) is an immunosuppressive cytokine that induces regulatory T cell (Tregs) differentiation and is involved in immune evasion mechanisms in cancer. The inhibition of the TGF-β1 signaling pathway can suppress cancer progression and metastasis through the modulation of anticancer immune responses.

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Background: Rotator cuff tears (RCTs) are often associated with severe shoulder pain. Non-steroidal anti-inflammatory drugs, not recommended for long-term use, do not effectively manage RCT-induced pain, resulting in reduced quality of life. To improve management, a better understanding of the fundamental properties of RCT pain is needed.

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Cancer is one of the most significant causes of death in dogs. Antibody drugs targeting the PD-1/PD-L1 axis represent a promising immunotherapy for both human and canine cancers. However, the regulation mechanisms of PD-L1 expression in canine cancers require further investigation to better understand the resistance mechanisms to anti-PD-L1 therapy.

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Recently, we demonstrated that Rac1 upregulation is involved in augmented bronchial smooth muscle (BSM) contractions of antigen-challenged mice. However, change in G protein-coupled receptor (GPCR)-induced Rac1 activation remains unknown in BSMs of repeatedly antigen-challenged (Chal.) mice.

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There has been considerable research on the involvement of RhoA/Rho kinase signalling in smooth muscle contractions. However, only a few reports have addressed the specific role of Rac1, which is a member of the Rho GTPase superfamily. Therefore, this study investigated the role of Rac1-related pathways in bronchial smooth muscle (BSM) contractions.

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VGF nerve growth factor inducible (VGF) is a polypeptide that is induced by neurotrophic factors and is involved in neurite growth and neuroprotection. The mRNA of the Vgf gene has been detected in the adult rat retina, however the roles played by VGF in the retina are still undetermined. Thus, the purpose of this study was to determine the effects of VGF on the retinal ganglion cells (RGCs) of mice in the optic nerve crush (ONC) model, rat-derived primary cultured RGCs and human induced pluripotent stem cells (iPSCs)-derived RGCs.

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Toll-like receptor 4 (TLR4) plays key roles in innate immune responses and inflammatory reactions. TAK-242 (resatorvid) is a small-molecule cyclohexene derivative that selectively inhibits TLR4 signaling pathways and suppresses inflammatory reactions. Here we investigated the protective effects of TAK-242 against optic nerve crush (ONC) which induces axonal injury like glaucoma in mice.

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Objectives: We sought to clarify the mechanism for neovascularization by ultrasonic microbubble destruction (US/MB) and its ability to improve the function of ischemic limbs.

Background: In tissue, US/MB can cause capillary rupture, leading to angiogenesis and arteriogenesis.

Methods: Seven days after removal of the femoral artery (day 0) in mice, microbubble/ultrasound treatment was performed by intermittent insonation (1.

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Objectives: We examined whether ultrasonic microbubble destruction (US/MB) enables therapeutic myocardial gene transfer of hepatocyte growth factor (HGF) for acute myocardial infarction (MI).

Background: Hepatocyte growth factor gene transfer provides cardioprotective effects in MI, which requires direct intramyocardial injection or special vectors. Although US/MB was used in myocardial gene transfer, its feasibility in transfer of a therapeutic gene with non-viral vector remains unknown.

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Article Synopsis
  • The study investigated the effects of early pravastatin treatment on glucose intolerance and heart health in a type II diabetes model using OLETF rats.
  • Results showed that treated OLETF rats had significantly lower rates of diabetes and maintained better heart function compared to untreated counterparts.
  • Pravastatin treatment also reduced harmful cardiac factors while promoting the expression of protective substances, suggesting its potential as an early intervention for diabetes-related cardiovascular issues.
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