Publications by authors named "Masashi Kurachi"

White matter infarct induces demyelination and brain dysfunction. We previously reported that transplantation of brain microvascular endothelial cells improved the behavioral outcome and promoted remyelination by increasing the number of oligodendrocyte precursor cells in the rat model of white matter infarct. In this study, we investigated the effects of transplantation of vascular endothelial cells generated from human induced pluripotent stem cells (iPSCs) on the rat model of white matter infarct.

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Subcortical white matter infarction causes ischemic demyelination and loss of brain functions, as the result of disturbances of the blood flow. Although angiogenesis is one of the recovery processes after cerebral infarction, the dynamics of revascularization after white matter infarction still remains unclear. We induced white matter infarction in the internal capsule of Flk1-GFP::Flt1-tdsRed double transgenic mice by injection of endothelin-1 (ET-1), a vasoconstrictor peptide, together with N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, and followed the changes in Flk1 and Flt1 expression in the vascular system in the infarct area.

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X-ray irradiation (X-irradiation) induces disruption of the blood-brain barrier (BBB). However, the mechanisms underlying the permeability changes are unclear. Therefore, in the present study, we examined the cellular and molecular changes produced by X-irradiation of the brain.

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We previously reported that BMP4 does not promote proliferation or differentiation of CD44-positive astrocyte precursor cells (APCs) but greatly promotes their survival in the presence of fibroblast growth factor-2 (FGF-2). In this study, we examined if BMP4 acts as a survival factor also for neural stem/progenitor cells (NPCs) isolated from ganglionic eminence of neonatal mouse brain. We found BMP4 promotes survival but not proliferation or differentiation of these cells, just as in the case for CD44-positive APCs.

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We previously reported transplantation of brain microvascular endothelial cells (MVECs) into cerebral white matter infarction model improved the animal's behavioral outcome by increasing the number of oligodendrocyte precursor cells (OPCs). We also revealed extracellular vesicles (EVs) derived from MVECs promoted survival and proliferation of OPCs in vitro. In this study, we investigated the mechanism how EVs derived from MVECs contribute to OPC survival and proliferation.

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Aims: The prevalence of major depressive disorder (MDD) is higher in women than in men, and this may be due to the decline in estrogen levels that occurs during the menopausal transition. We studied the biological alterations in the medial prefrontal cortex (mPFC), which is a region that is highly implicated in the neurobiology of MDD, and the blood cells (BCs) of ovariectomized (OVX) mice subjected to chronic mild stress (CMS), which represents a mouse model of depression during menopause.

Main Methods: The mPFC and the BCs were obtained from the same individuals.

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We previously examined the effect of brain microvascular endothelial cell (MVEC) transplantation on rat white matter infarction, and found that MVEC transplantation promoted remyelination of demyelinated axons in the infarct region and reduced apoptotic death of oligodendrocyte precursor cells (OPCs). We also found that the conditioned medium (CM) from cultured MVECs inhibited apoptosis of cultured OPCs. In this study, we examined contribution of extracellular vesicles (EVs) contained in the CM to its inhibitory effect on OPC apoptosis.

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We investigated transcriptomic markers of late-onset major depressive disorder (LOD; onset age of first depressive episode ≥ 50 years) from the genes expressed in blood cells and identified state-dependent transcriptomic markers in these patients. We assessed the genes expressed in blood cells by microarray and found that the expression levels of 3,066 probes were state-dependently changed in the blood cells of patients with LOD. To select potential candidates from those probes, we assessed the genes expressed in the blood of an animal model of depression, ovariectomized female mice exposed to chronic ultra-mild stress, by microarray and cross-matched the differentially expressed genes between the patients and the model mice.

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We previously showed that transplantation of brain microvascular endothelial cells (MVECs) greatly stimulated remyelination in the white matter infarct of the internal capsule (IC) induced by endothelin-1 injection and improved the behavioral outcome. In the present study, we examined the effect of MVEC transplantation on the infarct volume using intermittent magnetic resonance image and on the behavior of oligodendrocyte lineage cells histochemically. Our results in vivo show that MVEC transplantation reduced the infarct volume in IC and apoptotic death of oligodendrocyte precursor cells (OPCs).

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We previously reported that CD44-positive cells were candidates for astrocyte precursor cells in the developing cerebellum, because cells expressing high levels of CD44 selected by fluorescence-activated cell sorting (FACS) gave rise only to astrocytes in vitro. However, whether CD44 is a specific cell marker for cerebellar astrocyte precursor cells in vivo is unknown. In this study, we used immunohistochemistry, in situ hybridization, and FACS to analyze the spatial and temporal expression of CD44 and characterize the CD44-positive cells in the mouse cerebellum during development.

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It has been long speculated that specific signals are transmitted from photoreceptors to the retinal pigment epithelium (RPE). However, such signals have not been identified. In this study, we examined the retinal expression and localization of acetylcholine-related molecules as putative candidates for these signals.

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Ischemic insults affecting the internal capsule result in sensory-motor disabilities which adversely affect the patient's life. Cerebral endothelial cells have been reported to exert a protective effect against brain damage, so the transplantation of healthy endothelial cells might have a beneficial effect on the outcome of ischemic brain damage. In this study, endothelin-1 (ET-1) was injected into the rat internal capsule to induce lacunar infarction.

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Neural stem cells are generally considered to be committed to becoming precursor cells before terminally differentiating into either neurons or glial cells during neural development. Neuronal and oligodendrocyte precursor cells have been identified in several areas in the murine central nervous system. The presence of astrocyte precursor cells (APCs) is not so well understood.

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Molecules that have crucial functions in both nervous and vascular systems have attracted keen attention recently, and the name "angioneurins" has been proposed. The most striking example of angioneurins is vascular endothelial growth factor A (VEGF), which was originally identified as a key regulator of angiogenesis and has only recently been found to have important functions in the nervous system. In this study, we compared VEGF expression in the vasculature in the brain with that in the aorta and the vasculature in the kidney in mice.

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We used direct buckling force measurements with optical traps to determine the flexural rigidity of individual microtubules bound to polystyrene beads. To optimize the accuracy of the measurement, we used two optical traps and antibody-coated beads to manipulate each microtubule. We then applied a new analytical model assuming nonaxial buckling.

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Members of the stathmin-like protein family depolymerize microtubules (MTs), probably due to the ability of each stathmin monomer to bind two tubulin heterodimers in a complex (T(2)S complex). SCG10, a member of this family, is localized in the growth cone of neurons. It has four identified sites of serine phosphorylation (S50, S63, S73, and S97).

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Evidence is presented to demonstrate that colour polymorphism in a beetle arises from structural colours produced by a five-layered reflector in the elytron. The colour of leaf beetles, Plateumaris sericea, ranges across the visible spectrum from blackish-blue to red. The elytra have two distinct layers: epicuticle and exocuticle.

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