Biology subjects

Mizoguchi, H.

Publications and source records attributed to Mizoguchi, H..

7 recordsLinked to original sources

bioRxiv2025

The caninized anti-canine PD-1 monoclonal antibody in canine oral malignant melanoma: Efficacy and exploratory biomarker analysis

BackgroundCanine oral malignant melanoma (OMM) is a highly aggressive tumor with few treatment options. Because of its biological similarity to human mucosal melanoma, canine OMM represents a valuable spontaneous model for translational immunotherapy studies. Anti-PD-1 antibody therapy has shown promise in canine OMM; however, predictive biomarkers for treatment response and survival have not been identified. MethodsWe conducted a multicenter, prospective, investigator-initiated clinical trial to evaluate the safety and efficacy of a caninized anti-canine PD-1 monoclonal antibody (ca-4F12-E6) in 150 dogs with advanced OMM. The dogs were administered 3 mg/kg ca-4F12-E6 intravenously every two weeks. Treatment response was assessed using cRECIST v1.0. Biomarker analyses included peripheral blood parameters, cytokine/chemokines, peripheral lymphocyte subsets, microsatellite instability (MSI), immunohistochemistry for immune cell and mismatch repair protein markers, and RNA sequencing of the tumor tissue. Associations with clinical outcomes were determined by logistic regression and Cox proportional hazard models. ResultsThe best overall response rate was 16.7%. Treatment-related adverse events occurred in 40.0% of the dogs, which were primarily grade 1-3. Increased baseline white blood cell, neutrophil count, and C-reactive protein (CRP) levels were significantly associated with poor response, shorter progression-free survival (PFS), and reduced overall survival (OS). MSI-high tumors were associated with significantly prolonged OS compared with MSI-low/microsatellite stable tumors. Transcriptome analysis revealed differentially expressed genes and enriched immune-related pathways in responders, though limited by sample size. Conclusionca-4F12-E6 exhibited durable antitumor activity and an acceptable safety profile in dogs with OMM. Baseline systemic inflammatory markers and MSI status may serve as predictive biomarkers for clinical outcomes. The results support the use of canine OMM as a comparative model for human immuno-oncology and biomarker discovery.

cancer biology↗

bioRxiv2025

Distinct effects of nonselective Rho-kinase inhibitor fasudil and selective Rho-kinase 2 inhibitor KD025 on serotonin and dopamine release in the nucleus accumbens of mice

Recent studies have indicated that the Rho GTPase family and Rho-kinases are associated with psychiatric diseases, such as schizophrenia. Rho-kinases have two subtypes, Rho-kinases 1 and 2 that regulate actin dynamics and mediate neurite outgrowth, spine morphology in neurons, and neurotransmitter release in vitro and ex vivo. However, the precise role of Rho-kinases in neurotransmitter release in vivo remains unclear. To clarify the role of Rho-kinases 1 and 2 in serotonin and dopamine release in the nucleus accumbens (NAc) of mice in vivo, we investigated the effect of a nonselective Rho-kinase inhibitor, fasudil, and a selective Rho-kinase 2 inhibitor, KD025, using an in vivo microdialysis technique. Fasudil perfusion (1-20 M) into the NAc increased the basal extracellular serotonin level but did not affect dopamine levels, whereas KD025 (10-20 M) had little effect on basal serotonin and dopamine levels. Notably, fasudil perfusion into the NAc suppressed depolarization-induced serotonin and dopamine release in a dose-dependent manner, whereas KD025 selectively suppressed depolarization-induced serotonin release. Our results suggested that Rho-kinases 1 and 2 are associated with dopamine and serotonin release, respectively, and that both may have significant but distinct roles in the regulation of serotonin and dopamine release in the NAc.

neuroscience↗

bioRxiv2025

Cortical excitatory and inhibitory neuron deficits may underlie the cognitive and social impairments in a mouse model of schizophrenia with exonic Reln deletion

Reelin is an essential extracellular matrix glycoprotein involved in the formation of cortical layers and has been associated with several neuropsychiatric conditions, such as schizophrenia (SCZ). To explore its role in brain function and its potential involvement in SCZ, we developed a Reln heterozygous deletion (Relndel/+) mouse model that mimics a genetic deletion observed in a Japanese patient with SCZ. In previous studies, we demonstrated that Relndel/+ mice exhibit cognitive impairments in a visual discrimination test. Here, we found that Relndel/+ mice displayed impairments in social novelty recognition, while social preference remained intact. Immunohistochemical analyses revealed a significant decrease in the numbers of calcium/calmodulin-dependent protein kinase II (CaMKII)-positive glutamatergic pyramidal neurons, gamma-aminobutyric acid (GABA)-ergic interneurons, and parvalbumin (PV)-positive interneurons in the medial prefrontal cortex (mPFC) of Relndel/+ mice. Furthermore, Relndel/+ mice exhibited significant deficits in excitatory spine density and morphology, as well as a decrease number of PV boutons in the mPFC compared to wild-type (WT) mice. Finally, we demonstrated that injection of AAV-R36-Myc virus into the mPFC can improve social novelty impairments in Relndel/+ mice, but no effects on WT control. These findings indicate that Relndel/+ mice could be a valuable model for exploring the neurobiological mechanisms underlying cognitive and social impairments in SCZ. Futhermore, our results with AAV-R36-Myc also suggest the therapeutic potential of Reelin replacement, warranting further investigation as a possible treatment strategy for SCZ. HighlightsO_LIReelin deficiency disrupts social novelty, but not social preference, in Relndel/+ mice C_LIO_LIRelndel/+ mice serve as a novel model to investigate impairments of neuronal mechanisms on schizophrenia C_LIO_LIAAV-R36-myc injection rescues social novelty deficits in Relndel/+ mice C_LIO_LIReelin replacement therapy is a potential treatment for schizophrenia C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=143 HEIGHT=200 SRC="FIGDIR/small/666057v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@1f4921aorg.highwire.dtl.DTLVardef@1a41b33org.highwire.dtl.DTLVardef@f5f2bcorg.highwire.dtl.DTLVardef@1134d8d_HPS_FORMAT_FIGEXP M_FIG C_FIG

animal behavior and cognition↗

bioRxiv2025

Twinfilin-1 phosphorylation in reelin signaling regulates actin dynamics and spine development

Reelin is an extracellular glycoprotein essential for neuronal migration, spine development, and synaptic plasticity. Impaired reelin signaling is linked to neurological disorders, including schizophrenia and autism. While reelin mutant (reeler) mice exhibit behavioral deficits associated with impaired spine formation, the underlying molecular mechanisms remain unclear. We identified Twinfilin-1 (Twf1) as a downstream effector of reelin signaling via phosphoproteomic analysis, based on its reduced tyrosine phosphorylation in reeler mice. We found that Src regulated Twf1 phosphorylation at tyrosine 309, and reelin stimulation increased Twf1 phosphorylation in neurons, an effect blocked by the Src inhibitor PP2. A phospho-resistant Twf1 mutant (Twf1 Y309F) showed reduced capping protein binding and a lower F/G-actin ratio. Twf1Y309F mice exhibited cognitive deficits, reduced spine density, smaller spine head size, and a decreased F/G-actin ratio in synaptosomes. These findings highlight Twf1 phosphorylation as a key component of reelin signaling involved in actin remodeling and spine development.

neuroscience↗

bioRxiv2025

Involvement of orexin nerves in early stage of Alzheimer's disease model mice and preventive effect of orexin receptor antagonists

BackgroundMild cognitive impairment (MCI) is a condition between healthy cognition and dementia with a high probability of progression to Alzheimers disease (AD). Elevated levels of orexin (OX) have been reported in the cerebrospinal fluid of patients with MCI and AD. ObjectiveTo investigate the efficacy of dual OX receptor antagonists (suvorexant and lemborexant) in an early-stage AD mouse model (App-KI). MethodsThe expression of the OX receptor gene, the levels of suvorexant and lemborexant in the brain after a single oral dose, and their effects on locomotor activity were investigated in wild-type mice. In addition, the cognitive function of wild-type and App-KI mice was assessed using the Y-maze test after oral administration of suvorexant or lemborexant once a day for 60 d. After the behavioral test, amyloid-beta levels were quantified in the hippocampal CA1 region of App-KI mice. ResultsThe expression of the OX receptor gene was highest in the lateral hypothalamus and was also observed in other brain regions. Drug levels peaked at 20-40 min for suvorexant and 15 min for lemborexant and declined, still detectable 24 h later. Locomotor activity was reduced after suvorexant or lemborexant administration; however, 24 h after administration, locomotor activity did not differ from the control group. In particular, the Y-maze test showed that suvorexant and lemborexant prevented cognitive impairment in App-KI mice. Furthermore, suvorexant and lemborexant suppressed amyloid-beta accumulation in the hippocampal CA1 region of App-KI mice. ConclusionThe results suggest that suvorexant and lemborexant effectively suppress the early stages of AD.

animal behavior and cognition↗

bioRxiv2024

Antipsychotic-like effects of the selective Rho-kinase 2 inhibitor KD025 in genetic and pharmacological mouse models of schizophrenia

1Copy number variations in the ARHGAP10 gene encoding Rho GTPase-activating protein 10 are significantly associated with schizophrenia. ARHGAP10 negatively regulates RhoA/Rho-kinase (ROCK) signaling. We previously demonstrated that fasudil, a non-selective ROCK inhibitor, exhibited antipsychotic-like effects in several mouse models of schizophrenia. ROCK has two subtypes, ROCK1 and ROCK2. ROCK1 is mainly expressed in the thymus and blood, while ROCK2 is predominantly expressed in the brain. Therefore, it is expected that like fasudil, selective ROCK2 inhibitors will exhibit antipsychotic-like effects, accompanied by a lower incidence of adverse effects due to ROCK1 inhibition. Here, we used genetic and pharmacological models of schizophrenia to investigate whether the selective ROCK2 inhibitor KD025 would show antipsychotic-like effects with a favorable adverse effect profile. Oral administration of KD025 suppressed the abnormal increase in the phosphorylation level of myosin phosphatase-targeting subunit 1, a substrate of ROCK, and ameliorated the decreased spine density of layer 2/3 pyramidal neurons in the medial prefrontal cortex of Arhgap10 S490P/NHEJ mice. Furthermore, KD025 mitigated the methamphetamine-induced impairment of visual discrimination (VD) in Arhgap10 S490P/NHEJ and wild-type mice. KD025 also reduced MK-801-induced impairments of VD, novel object recognition, and hyperlocomotion. Regarding side effects that are commonly seen with typical antipsychotics, KD025 did not affect systolic blood pressure and did not induce extrapyramidal symptoms, hyperprolactinemia, or hyperglycemia at the effective dosage in naive wild-type mice. Taken together, KD025 shows antipsychotic-like effects with a favorable adverse effect profile in genetic and pharmacological mouse models of schizophrenia.

pharmacology and toxicology↗

bioRxiv2021

A machine learning model that emulates experts decision making in vancomycin initial dose planning

Vancomycin is a glycopeptide antibiotic that has been used primarily in the treatment of methicillin-resistant Staphylococcus aureus infections. To enhance its clinical effectiveness and prevent nephrotoxicity, therapeutic drug monitoring (TDM) of trough concentrations is recommended. Initial vancomycin dosing regimens are determined based on patient characteristics such as age, body weight, and renal function, and dosing strategies to achieve therapeutic concentration windows at initial TDM have been extensively studied. Although numerous dosing nomograms for specific populations have been developed, no comprehensive strategy exists for individually tailoring initial dosing regimens; therefore, decision making regarding initial dosing largely depends on each clinicians experience and expertise. In this study, we applied a machine-learning (ML) approach to integrate clinician knowledge into a predictive model for initial vancomycin dosing. A dataset of vancomycin initial dose plans defined by pharmacists experienced in vancomycin TDM (i.e., experts) was used to build the ML model. The target trough concentration was attained at comparable rates with the model- and expert-recommended dosing regimens, suggesting that the ML model successfully incorporated the experts knowledge. The predictive model developed here will contribute to improved decision making for initial vancomycin dosing and early attainment of therapeutic windows.

pharmacology and toxicology↗