Publications by authors named "IKAWA M"

In mammals, blastocyst-stage trophectoderm (TE) contacts the maternal body at the time of implantation and forms the placenta after implantation, which supports the development of the fetus. Studying gene function in TE and placenta is important to understand normal implantation and pregnancy processes and their dysfunction. However, genetically modified mice are commonly generated by manipulating pronuclear-stage zygotes, which modify both the genome of the fetus and the placenta.

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Spermatogenesis is one of the most complex processes of cell differentiation and its failure is a major cause of male infertility. Therefore, a proper model that recapitulates spermatogenesis in vitro has been long sought out for basic and clinical research. Testis organ culture using the gas-liquid interphase method has been shown to support spermatogenesis in mice and rats.

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One in five couples who wish to conceive is infertile, and half of these couples have male infertility. However, the causes of male infertility are still largely unknown. Creatine is stored in the body as an energy buffer, and the testes are its second-largest reservoir after muscles.

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One of the major age-related declines in female reproductive function is the reduced quantity and quality of oocytes. Here we demonstrate that structural changes in the zona pellucida (ZP) were associated with decreased fertilization rates from 34- to 38-week-old female mice, equivalent to the mid-reproductive of human females. In middle-aged mouse ovaries, the decline in the number of transzonal projections was accompanied by a decrease in cumulus cell-oocyte interactions, resulting in a deterioration of the oocyte quality.

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Embryo implantation is crucial for successful pregnancy, requiring appropriate uterine responses to implantation-competent blastocysts. Molecular communication at the maternal-fetal junction governs this process. Leukemia inhibitory factor (Lif) plays a pivotal role in implantation across species.

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Background: Inhibition of sperm maturation in the epididymis is a promising post-testicular strategy for short-acting male contraceptives. It has been shown that ROS1, a receptor tyrosine kinase expressed in the epididymis, is essential for epididymal differentiation, sperm maturation, and male fertility in mice. However, it is unknown if inhibition of ROS1 suppresses male fertility reversibly.

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Fertilization, the basis for sexual reproduction, culminates in the binding and fusion of sperm and egg. Although several proteins are known to be crucial for this process in vertebrates, the molecular mechanisms remain poorly understood. Using an AlphaFold-Multimer screen, we identified the protein Tmem81 as part of a conserved trimeric sperm complex with the essential fertilization factors Izumo1 and Spaca6.

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Article Synopsis
  • * Research shows that USF2, in conjunction with HDAC1, represses lysosomal and autophagy genes when nutrients are abundant by altering histone modifications and chromatin structure.
  • * Under starvation, USF2 competes with TFEB to control gene expression related to lysosomes, and findings suggest that targeting USF2 could be beneficial for treating diseases linked to protein aggregation, like α1-antitrypsin deficiency.
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  • Advanced genetic studies have identified mutations in the FUS/TLS gene, important for DNA repair and RNA processing, as a cause of familial ALS.
  • A CRISPR-Cas9 technique was used to create mouse models with the FUS-ALS mutation, which exhibited progressive motor impairment and neuron damage, similar to symptoms seen in ALS patients.
  • The findings support the idea that disruptions in nuclear structure are significant in ALS, highlighting the potential of these models for future research and therapy development.
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  • * Research using knockout (KO) mice lacking the Ccdc188 gene revealed that this gene is essential for male fertility, as these mice produced mostly acephalic sperm and were sterile.
  • * The study also showed that while the HTCA could assemble without CCDC188, it was unable to attach properly to the nucleus during sperm development, causing separation of the sperm head and neck, and a lack of mitochondrial sheath in the sperm.
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  • The study focuses on how chromatin structure changes during the development of multicellular organisms and highlights the role of histone variants in cell differentiation.
  • Researchers created knock-in mice with a FLAG tag on a testis-specific histone variant called H3t to better understand its function in vivo.
  • Through immunostaining and mass spectrometry, they found that H3t-FLAG was present in spermatogonia and meiotic cells, showing similarities and differences in posttranslational modifications compared to the standard histone H3.
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Spleen tyrosine kinase (Syk), a non-receptor-type tyrosine kinase, has a wide range of physiological functions. A possible role of Syk in Alzheimer's disease (AD) has been proposed. We evaluated the localization of Syk in the brains of patients with AD and control participants.

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Dishcook is a new cooking system that allows individual cooking using a dedicated induction heater. This study investigated whether Dishcook use affects the nutritional value of individuals with intellectual disabilities. This study was conducted on users receiving support from a continuous-employment office in Obama City, Fukui Prefecture, in 2022.

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Voltage-sensing phosphatase (VSP) exhibits voltage-dependent phosphatase activity toward phosphoinositides. VSP generates a specialized phosphoinositide environment in mammalian sperm flagellum. However, the voltage-sensing mechanism of VSP in spermatozoa is not yet characterized.

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Despite numerous biomarkers being proposed for rheumatoid arthritis (RA), a gap remains in our understanding of their mechanisms of action. In this study, we discovered a novel role for gelsolin (GSN), an actin-binding protein whose levels are notably reduced in the plasma of RA patients. We elucidated that GSN is a key regulator of NLRP3 inflammasome activation in macrophages, providing a plausible explanation for the decreased secretion of GSN in RA patients.

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Ribonucleoprotein (RNP) granules are membraneless electron-dense structures rich in RNAs and proteins, and involved in various cellular processes. Two RNP granules in male germ cells, intermitochondrial cement and the chromatoid body (CB), are associated with PIWI-interacting RNAs (piRNAs) and are required for transposon silencing and spermatogenesis. Other RNP granules in male germ cells, the reticulated body and CB remnants, are also essential for spermiogenesis.

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There are approximately 20 000 protein-coding genes in humans and mice. More than 1000 of these genes are predominantly expressed in the testis or are testis-specific and thought to play an important role in male reproduction. Through the production of gene knockout mouse models and phenotypic evaluations, many genes essential for spermatogenesis, sperm maturation, and fertilization have been discovered, greatly contributing to the elucidation of their molecular mechanisms.

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Article Synopsis
  • The sperm flagellar axoneme structure is crucial for sperm motility and is highly conserved across different species, aiding in fertilization.
  • Mycbpap is primarily expressed in mouse and human testes and is vital for male fertility; its absence disrupts docking between the centrosome and nuclear envelope, causing defects in flagellar development.
  • Research on transgenic mice showed that restoring MYCBPAP can recover fertility, and further studies revealed key protein interactions that highlight MYCBPAP’s role in regulating sperm tail formation and centrosome functions.
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Background: Sitting ability is an important prognostic factor for patients with acute stroke. However, the characteristics of trunk muscle activity and weight-bearing during sitting are unclear.

Research Question: Are trunk muscle activity and weight-bearing during static sitting associated with sitting ability in patients with acute stroke?

Methods: Trunk electromyography and sitting posturography were performed during static sitting in 20 patients with acute stroke.

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Article Synopsis
  • * Sperm cells, or spermatozoa, consist of a head (containing the acrosome) and a flagellum, which is crucial for movement and fertilization.
  • * The article reviews the development of functional spermatozoa in mammals, emphasizing the processes that involve acrosome and flagellum formation, based on studies of mouse models.
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Regulation of gene expression through histone modifications underlies cell homeostasis and differentiation. Kdm4d and Kdm4dl exhibit a high degree of similarity and demethylate H3K9me3. However, the physiological functions of these proteins remain unclear.

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Regulated neural-metabolic-inflammatory responses are essential for maintaining physiological homeostasis. However, the molecular machinery that coordinates neural, metabolic, and inflammatory responses is largely unknown. Here, we show that semaphorin 6D (SEMA6D) coordinates anxiogenic, metabolic, and inflammatory outputs from the amygdala by maintaining synaptic homeostasis.

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Sperm heads contain not only the nucleus but also the acrosome which is a distinctive cap-like structure located anterior to the nucleus and is derived from the Golgi apparatus. The Golgi Associated RAB2 Interactors (GARINs; also known as FAM71) protein family shows predominant expression in the testis and all possess a RAB2-binding domain which confers binding affinity to RAB2, a small GTPase that is responsible for membrane transport and vesicle trafficking. Our previous study showed that GARIN1A and GARIN1B are important for acrosome biogenesis and that GARIN1B is indispensable for male fertility in mice.

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Article Synopsis
  • Mice are a key model for studying human gene function due to their genetic similarities and advancements like CRISPR/Cas9 have sped up research on gene roles in male reproduction.
  • Researchers focused on 15 genes related to male fertility and created 13 gene-deficient mouse models, all of which showed normal fertility in natural breeding.
  • The study suggests that the investigated genes are not essential for male fertility, which could help streamline research efforts by preventing unnecessary duplication of studies on these non-essential genes.
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The glymphatic system is considered to play a pivotal role in the clearance of disease-causing proteins in neurodegenerative diseases. This study employed MR diffusion tensor imaging (DTI) to evaluate glymphatic system function and its correlation with brain amyloid accumulation levels measured using [C]Pittsburgh compound-B (PiB) PET/MRI. Fifty-six patients with mild cognitive impairment and early Alzheimer's disease (AD: 70 ± 11 y) underwent [C]PiB PET/MRI to assess amyloid deposition and were compared with 27 age-matched cognitively normal volunteers (CN: 69 ± 10y).

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