Publications by authors named "Sayoko Nishimura"

Background: Pulmonary embolism (PE) remains a major contributor to the global disease burden. However, disparities in international trends of PE-related mortality have not been comprehensively examined across geographic, economic, and healthcare system parameters. We employed multifaceted stratification to analyse long-term trends in PE-related mortality.

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Cerebral cortex development in humans is a highly complex and orchestrated process that is under tight genetic regulation. Rare mutations that alter gene expression or function can disrupt the structure of the cerebral cortex, resulting in a range of neurological conditions. Lissencephaly ('smooth brain') spectrum disorders comprise a group of rare, genetically heterogeneous congenital brain malformations commonly associated with epilepsy and intellectual disability.

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Background And Objective: Adverse drug events (ADEs) are becoming a significant public health issue. However, reports on ADE-related mortality are limited to national-level evaluations. Therefore, we aimed to reveal overall trends in ADE-related mortality across the 21st century on an international level.

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Hedgehog signaling mediates embryologic development of the central nervous system and other tissues and is frequently hijacked by neoplasia to facilitate uncontrolled cellular proliferation. Meningiomas, the most common primary brain tumor, exhibit Hedgehog signaling activation in 6.5% of cases, triggered by recurrent mutations in pathway mediators such as SMO.

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While somatic variants of  (Tumor necrosis factor receptor-associated factor 7) underlie anterior skull-base meningiomas, here we report the inherited mutations of  that cause congenital heart defects. We show that TRAF7 mutants operate in a dominant manner, inhibiting protein function via heterodimerization with wild-type protein. Further, the shared genetics of the two disparate pathologies can be traced to the common origin of forebrain meninges and cardiac outflow tract from the expressing neural crest.

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Context: X-linked hypophosphatemia (XLH) is a genetic disease, causing life-long hypophosphatemia due to overproduction of fibroblast growth factor 23 (FGF23). XLH is associated with Chiari malformations, cranial synostosis, and syringomyelia. FGF23 signals through FGFR1c and requires a coreceptor, α-Klotho, which is expressed in the renal distal convoluted tubules and the choroid plexus (ChP).

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Cerebrovascular disorders are underlain by perturbations in cerebral blood flow and abnormalities in blood vessel structure. Here, we provide an overview of the current knowledge of select cerebrovascular disorders that are associated with genetic lesions and connect genomic findings with analyses aiming to elucidate the cellular and molecular mechanisms of disease pathogenesis. We argue that a mechanistic understanding of genetic (familial) forms of cerebrovascular disease is a prerequisite for the development of rational therapeutic approaches, and has wider implications for treatment of sporadic (non-familial) forms, which are usually more common.

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Cerebral cavernous malformations (CCMs) are common vascular anomalies that develop in the central nervous system and, more rarely, the retina. The lesions can cause headache, seizures, focal neurological deficits, and hemorrhagic stroke. Symptomatic lesions are treated according to their presentation; however, targeted pharmacological therapies that improve the outcome of CCM disease are currently lacking.

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Cholecystokinin (CCK), a peptide hormone and one of the most abundant neuropeptides in vertebrate brain, mediates its actions via two G-protein coupled receptors, CCKAR and CCKBR, respectively active in peripheral organs and the central nervous system. Here, we demonstrate that the CCK receptors have a dynamic and largely reciprocal expression in embryonic and postnatal brain. Using compound homozygous mutant mice lacking the activity of both CCK receptors, we uncover their additive, functionally synergistic effects in brain development and demonstrate that CCK receptor loss leads to abnormalities of cortical development, including defects in the formation of the midline and corpus callosum, and cortical interneuron migration.

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Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype.

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The combination of family-based linkage analysis with high-throughput sequencing is a powerful approach to identifying rare genetic variants that contribute to genetically heterogeneous syndromes. Using parametric multipoint linkage analysis and whole exome sequencing, we have identified a gene responsible for microcephaly (MCP), severe visual impairment, intellectual disability, and short stature through the mapping of a homozygous nonsense alteration in a multiply-affected consanguineous family. This gene, DIAPH1, encodes the mammalian Diaphanous-related formin (mDia1), a member of the diaphanous-related formin family of Rho effector proteins.

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Loss of function of cerebral cavernous malformation 3 (CCM3) results in an autosomal dominant cerebrovascular disorder. Here, we uncover a developmental role for CCM3 in regulating neuronal migration in the neocortex. Using cell type-specific gene inactivation in mice, we show that CCM3 has both cell autonomous and cell non-autonomous functions in neural progenitors and is specifically required in radial glia and newly born pyramidal neurons migrating through the subventricular zone, but not in those migrating through the cortical plate.

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Oxidative stress-induced cell death plays a major role in the progression of ischemic acute renal failure. Using microarrays, we sought to identify a stress-induced gene that may be a therapeutic candidate. Human proximal tubule (HK2) cells were treated with hydrogen peroxide (H2O2) and RNA was applied to an Affymetrix gene chip.

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Background: Klotho is associated with the suppression of several ageing phenotypes. Because high klotho gene expression was detected in the kidney and several studies have found altered expression in animal models, we explored the physiological relevance of klotho expression in the kidney under renal ischemia reperfusion injury (IRI).

Methods: Male Wistar rats were subjected to bilateral renal ischemia or sham operation, followed by reperfusion for 6, 12 or 24 h, or 2 to 10 days.

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Background: CD2-associated protein (CD2AP) is a ubiquitously expressed 80-kDa intracellular protein, and has been speculated to act as an intracellular signaling pathway between plasma membrane proteins and cytoskeleton proteins. CD2AP expression has been reported in both the glomerulus and tubular epithelium in the kidney, and CD2AP knockout mice exhibit congenital nephrotic syndrome. However, the precise properties and its role in the renal tubules have not been clarified.

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Autosomal dominant polycystic kidney disease (ADPKD) occurs by germline mutation in PKD1 or PKD2. Evidence of homozygous inactivation of either gene in human cyst lining cells as well as in mouse knockout models strongly supports a two-hit mechanism for cyst formation. Discovery of trans-heterozygous mutations in PKD1 and PKD2 in a minority of human renal cysts has led to the proposal that such mutations also can play a role in cyst formation.

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Polycystin-2, the product of the gene mutated in type 2 autosomal dominant polycystic kidney disease (ADPKD), is the prototypical member of a subfamily of the transient receptor potential (TRP) channel superfamily, which is expressed abundantly in the endoplasmic reticulum (ER) membrane. Here, we show by single channel studies that polycystin-2 behaves as a calcium-activated, high conductance ER channel that is permeable to divalent cations. Epithelial cells overexpressing polycystin-2 show markedly augmented intracellular calcium release signals that are lost after carboxy-terminal truncation or by the introduction of a disease-causing missense mutation.

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