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1.
Glia ; 2020 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-32445516

RESUMO

Dystonin (Dst) is a causative gene for Dystonia musculorum (dt) mice, which is an inherited disorder exhibiting dystonia-like movement and ataxia with sensory degeneration. Dst is expressed in a variety of tissues, including the central nervous system and the peripheral nervous system (PNS), muscles, and skin. However, the Dst-expressing cell type(s) for dt phenotypes have not been well characterized. To address the questions whether the disruption of Dst in Schwann cells induces movement disorders and how much impact does it have on dt phenotypes, we generated Dst conditional knockout (cKO) mice using P0-Cre transgenic mice and Dst gene trap mice. First, we assessed the P0-Cre transgene-dependent Cre recombination using tdTomato reporter mice and then confirmed the preferential tdTomato expression in Schwann cells. In the Dst cKO mice, Dst mRNA expression was significantly decreased in Schwann cells, but it was intact in most of the sensory neurons in the dorsal root ganglion. Next, we analyzed the phenotype of Dst cKO mice. They exhibited a normal motor phenotype during juvenile periods, and thereafter, started exhibiting an ataxia. Behavioral tests and electrophysiological analyses demonstrated impaired motor abilities and slowed motor nerve conduction velocity in Dst cKO mice, but these mice did not manifest dystonic movements. Electron microscopic observation of the PNS of Dst cKO mice revealed significant numbers of hypomyelinated axons and numerous infiltrating macrophages engulfing myelin debris. These results indicate that Dst is important for normal PNS myelin organization and Dst disruption in Schwann cells induces late-onset neuropathy and sensory ataxia. MAIN POINTS: Dystonin (Dst) disruption in Schwann cells results in late-onset neuropathy and sensory ataxia. Dst in Schwann cells is important for normal myelin organization in the peripheral nervous system.

2.
Sci Rep ; 9(1): 19610, 2019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873139

RESUMO

Recent studies have examined the feedback pathway from the amygdala to the auditory cortex in conjunction with the feedforward pathway from the auditory cortex to the amygdala. However, these connections have not been fully characterized. Here, to visualize the comprehensive connectivity between the auditory cortex and amygdala, we injected cholera toxin subunit b (CTB), a bidirectional tracer, into multiple subfields in the mouse auditory cortex after identifying the location of these subfields using flavoprotein fluorescence imaging. After injecting CTB into the secondary auditory field (A2), we found densely innervated CTB-positive axon terminals that were mainly located in the lateral amygdala (La), and slight innervations in other divisions such as the basal amygdala. Moreover, we found a large number of retrogradely-stained CTB-positive neurons in La after injecting CTB into A2. When injecting CTB into the primary auditory cortex (A1), a small number of CTB-positive neurons and axons were visualized in the amygdala. Finally, we found a near complete absence of connections between the other auditory cortical fields and the amygdala. These data suggest that reciprocal connections between A2 and La are main conduits for communication between the auditory cortex and amygdala in mice.

3.
J Physiol ; 597(13): 3441-3455, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31087329

RESUMO

KEY POINTS: Neuropathic pain spreads spatially beyond the injured sites, and the mechanism underlying the spread has been attributed to inflammation occurring in the spinal cord. However, the spatial spread of spinal/cortical potentiation induced by conduction block of the peripheral nerves can be observed prior to inflammation. In the present study, we found that spreading potentiation and hypersensitivity acutely induced by unilateral hindpaw ischaemia are nitric oxide (NO)-dependent and that NO is produced by ischaemia and quickly diffuses within the spinal cord. We also found that NO production induced by ischaemia is not observed in the presence of an antagonist for group II metabotropic glutamate receptors (mGluRs) and that neuronal NO synthase-positive dorsal horn neurons express group II mGluRs. These results suggest strongly that NO-mediated spreading potentiation in the spinal cord is one of the trigger mechanisms for neuropathic pain. ABSTRACT: Cortical/spinal responses to hindpaw stimulation are bilaterally potentiated by unilateral hindpaw ischaemia in mice. We tested the hypothesis that hindpaw ischaemia produces nitric oxide (NO), which diffuses in the spinal cord to induce spatially spreading potentiation. Using flavoprotein fluorescence imaging, we confirmed that the spreading potentiation in hindpaw responses was induced during ischaemia in the non-stimulated hindpaw. This spreading potentiation was blocked by spinal application of l-NAME, an inhibitor of NO synthase (NOS). Furthermore, no spreading potentiation was observed in neural NOS (nNOS) knockout mice. Spinal application of an NO donor was enough to induce cortical potentiation and mechanical hypersensitivity. The spatial distribution of NO during unilateral hindpaw ischaemia was visualized using 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM). An increase in fluorescence derived from the complex of DAF-FM with NO was observed on the ischaemic side of the spinal cord. A similar but smaller increase was also observed on the contralateral side. Somatosensory potentiation after hindpaw ischaemia is known to be inhibited by spinal application of LY354740, an agonist of group II metabotropic glutamate receptors (mGluRs). We confirmed that the spinal DAF-FM fluorescence increases during hindpaw ischaemia were not observed in the presence of LY354740. We also confirmed that approximately half of the nNOS-positive neurons in the superficial laminae of the dorsal horn expressed mGluR2 mRNA. These results suggest that disinhibition of mGluR2 produces NO which in turn induces a spreading potentiation in a wide area of the spinal cord. Such spreading, along with the consequent non-specific potentiation in the spinal cord, may trigger neuropathic pain.

5.
Eur J Neurosci ; 50(6): 2970-2987, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31012509

RESUMO

Feedback regulation from the higher association areas is thought to control the primary sensory cortex, contribute to the cortical processing of sensory information, and work for higher cognitive functions such as multimodal integration and attentional control. However, little is known about the underlying neural mechanisms. Here, we show that the posterior parietal cortex (PPC) persistently inhibits the activity of the primary visual cortex (V1) in mice. Activation of the PPC causes the suppression of visual responses in V1 and induces the short-term depression, which is specific to visual stimuli. In contrast, pharmacological inactivation of the PPC or disconnection of cortical pathways from the PPC to V1 results in an effect of transient enhancement of visual responses in V1. Two-photon calcium imaging demonstrated that the cortical disconnection caused V1 excitatory neurons an enhancement of visual responses and a reduction of orientation selectivity index (OSI). These results show that the PPC regulates the response properties of V1 excitatory neurons. Our findings reveal one of the functions of the PPC, which may contribute to higher brain functions in mice.

6.
Cereb Cortex ; 28(12): 4424-4439, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30272122

RESUMO

Tonotopy is an essential functional organization in the mammalian auditory cortex, and its source in the primary auditory cortex (A1) is the incoming frequency-related topographical projections from the ventral division of the medial geniculate body (MGv). However, circuits that relay this functional organization to higher-order regions such as the secondary auditory field (A2) have yet to be identified. Here, we discovered a new pathway that projects directly from MGv to A2 in mice. Tonotopy was established in A2 even when primary fields including A1 were removed, which indicates that tonotopy in A2 can be established solely by thalamic input. Moreover, the structural nature of differing thalamocortical connections was consistent with the functional organization of the target regions in the auditory cortex. Retrograde tracing revealed that the region of MGv input to a local area in A2 was broader than the region of MGv input to A1. Consistent with this anatomy, two-photon calcium imaging revealed that neuronal responses in the thalamocortical recipient layer of A2 showed wider bandwidth and greater heterogeneity of the best frequency distribution than those of A1. The current study demonstrates a new thalamocortical pathway that relays frequency information to A2 on the basis of the MGv compartmentalization.


Assuntos
Córtex Auditivo/citologia , Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Corpos Geniculados/citologia , Corpos Geniculados/fisiologia , Neurônios/citologia , Neurônios/fisiologia , Estimulação Acústica , Animais , Vias Auditivas/citologia , Vias Auditivas/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Técnicas de Rastreamento Neuroanatômico
7.
Sci Rep ; 8(1): 7678, 2018 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-29769630

RESUMO

Propagation of oscillatory spike firing activity at specific frequencies plays an important role in distributed cortical networks. However, there is limited evidence for how such frequency-specific signals are induced or how the signal spectra of the propagating signals are modulated during across-layer (radial) and inter-areal (tangential) neuronal interactions. To directly evaluate the direction specificity of spectral changes in a spiking cortical network, we selectively photostimulated infragranular excitatory neurons in the rat primary visual cortex (V1) at a supra-threshold level with various frequencies, and recorded local field potentials (LFPs) at the infragranular stimulation site, the cortical surface site immediately above the stimulation site in V1, and cortical surface sites outside V1. We found a significant reduction of LFP powers during radial propagation, especially at high-frequency stimulation conditions. Moreover, low-gamma-band dominant rhythms were transiently induced during radial propagation. Contrastingly, inter-areal LFP propagation, directed to specific cortical sites, accompanied no significant signal reduction nor gamma-band power induction. We propose an anisotropic mechanism for signal processing in the spiking cortical network, in which the neuronal rhythms are locally induced/modulated along the radial direction, and then propagate without distortion via intrinsic horizontal connections for spatiotemporally precise, inter-areal communication.


Assuntos
Potenciais de Ação , Potenciais Evocados Visuais , Neurônios/fisiologia , Periodicidade , Córtex Visual/fisiologia , Animais , Channelrhodopsins/genética , Channelrhodopsins/metabolismo , Eletroencefalografia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Neurônios/citologia , Estimulação Luminosa , Ratos , Ratos Long-Evans , Córtex Visual/citologia
8.
Anat Sci Int ; 93(1): 119-127, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27888476

RESUMO

Oligodendrocytes (OLs) are glial cells that form myelin sheaths surrounding the axons in the central nervous system (CNS). Jimpy (jp) mutant mice are dysmyelinating disease models that show developmental abnormalities in myelinated OLs in the CNS. The causative gene in jp mice is the proteolipid protein (PLP) located on the X chromosome. Mutations in the jp allele result in exon 5 skipping and expression of abnormal PLP containing a C-terminal frame shift. Many lines of evidence suggest that abnormal PLP in OLs results in endoplasmic reticulum (ER) stress and cell death. To histologically detect glial responses in the jp mutant brain, we performed staining with lineage-specific markers. Using OL markers and OL progenitor cell marker staining, we identified reduced numbers of OL lineage cells in the jp mutant brain. Nuclear staining of the transcription factor Olig1 was observed in the Tabby-jp brain, whereas cytoplasmic Olig1 staining was observed in the wild-type brain at postnatal day 21, suggesting that active myelination was present in the mutant brain. Many microglial cells with activated morphology and intensive staining of CD11b microglia marker were observed in the internal capsule of the mutant brain, a region of white matter containing residual OLs. Activated astrocytes with high glial fibrillary acidic protein-immunoreactivity were also mainly observed in white matter. Finally, we performed in situ hybridization using C/EBP homologous protein (CHOP) antisense probes to detect ER stressed cells. CHOP mRNA was strongly expressed in residual OLs in the Tabby-jp mutant mice at postnatal stages. These data show that microglia and astrocytes exhibit dynamic glial activation in response to cell death of OLs during Tabby-jp pathogenesis, and that CHOP antisense probes may be a good marker for the detection of ER-stressed OLs in jp mutant mice.


Assuntos
Encéfalo/citologia , Encéfalo/patologia , Doenças Desmielinizantes/genética , Doenças Desmielinizantes/patologia , Estresse do Retículo Endoplasmático , Oligodendroglia/patologia , Animais , Elementos Antissenso (Genética) , Morte Celular , Modelos Animais de Doenças , Feminino , Hidroxietilrutosídeo , Masculino , Camundongos Mutantes , Proteína Proteolipídica de Mielina/genética , Proteína Proteolipídica de Mielina/metabolismo , Oligodendroglia/metabolismo , RNA Mensageiro/metabolismo , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Cromossomo X/genética
9.
Neurochem Int ; 119: 159-170, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29061384

RESUMO

Dystonia musculorum (dt) mice, which have a mutation in the Dystonin (Dst) gene, are used as animal models to investigate the human disease known as hereditary sensory and autonomic neuropathy type VI. Massive neuronal cell death is observed, mainly in the peripheral nervous system (PNS) of dt mice. We and others have recently reported a histopathological feature of these mice that neurofilament (NF) accumulates in various areas of the central nervous system (CNS), including motor pathways. Although dt mice show motor disorder and growth retardation, the causes for these are still unknown. Here we performed histopathological analyses on motor units of the trigeminal motor nucleus (Mo5 nucleus), because they are a good system to understand neuronal responses in the mutant CNS, and abnormalities in this system may lead to problems in mastication, with subsequent growth retardation. We report that motoneurons with NF accumulation in the Mo5 nuclei of DstGt homozygous mice express the stress-induced genes CHOP, ATF3, and lipocalin 2 (Lcn2). We also show a reduced number of Mo5 motoneurons and a reduced size of Mo5 nuclei in DstGt homozygous mice, possibly due to apoptosis, given the presence of cleaved caspase 3-positive Mo5 motoneurons. In the mandibular (V3) branches of the trigeminal nerve, which contains axons of Mo5 motoneurons and trigeminal sensory neurons, there was infiltration of Iba1-positive macrophages. Finally, we report atrophy of the masseter muscles in DstGt homozygous mice, which showed abnormal nuclear localization of myofibrils and increased expression of atrogin-1 mRNA, a muscle atrophy-related gene and weaker masseter muscle strength with uncontrolled muscle activity by electromyography (EMG). Taken together, our findings strongly suggest that mastication in dt mice is affected due to abnormalities of Mo5 motoneurons and masseter muscles, leading to growth retardation at the post-weaning stages.


Assuntos
Axônios/metabolismo , Distonia/metabolismo , Músculo Masseter/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Núcleo Motor do Nervo Trigêmeo/metabolismo , Animais , Proteínas de Transporte/metabolismo , Proteínas do Citoesqueleto/metabolismo , Camundongos Transgênicos , Neurônios Motores/metabolismo , Células Receptoras Sensoriais/metabolismo
10.
Neurochem Res ; 43(1): 101-109, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28664402

RESUMO

Dystonia musculorum (dt) mice show sensory neurodegeneration and movement disorder, such as dystonia and cerebellar ataxia. The causative gene Dystonin (Dst) encodes a cytoskeleton linker protein. Although sensory neurodegeneration has been well studied, glial cell responses in the central nervous system (CNS) are poorly understood. Here, we investigated cell proliferation in the CNS of Dst Gt homozygous mice using newly generated in situ hybridization (ISH) probes-Ki-67 and proliferating cell nuclear antigen (PCNA) probes-both of which effectively detect proliferating cells. We found that Ki-67-positive cells were significantly decreased in the corpus callosum and thalamus of dt brain at postnatal day 21 (P21). There is a similar but not significant tendency at postnatal day 14 (P14) in the dt brain. We also confirmed the reduced proliferation by PCNA ISH and Ki-67 immunohistochemistry. Double staining with cell-type-specific markers revealed that proliferating cells are oligodendrocyte progenitor cells (OPCs) in both wild-type and dt brain. We also observed a reduced number of Olig2-positive cells in the corpus callosum of Dst Gt homozygous mice at P21, indicating that reduced proliferation resulted in a reduced number of OPCs. Our data indicate that OPCs proliferation is reduced in the dt mouse brain at the postnatal stage and that it subsequently results in the reduced number of OPCs.


Assuntos
Encéfalo/citologia , Citoesqueleto/metabolismo , Células Precursoras de Oligodendrócitos/citologia , Oligodendroglia/citologia , Animais , Proliferação de Células/fisiologia , Proteínas do Citoesqueleto/metabolismo , Camundongos Transgênicos , Microtúbulos/metabolismo , Proteínas do Tecido Nervoso/metabolismo
11.
J Heart Lung Transplant ; 36(10): 1087-1096, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28942783

RESUMO

BACKGROUND: In Japan, ventricular assist devices (VADs) have been used for patients with severe heart failure as a bridge to transplantation (BTT) since 1992. However, it was not until 1997, when the Organ Transplant Law was enacted, that medical devices received approval by the national health insurance system for that use. To encourage research and development of innovative medical devices, the Pharmaceuticals and Medical Devices Agency has established a public-private partnership in collaboration with academic societies, hospitals and manufacturers. METHODS: The Japanese registry for Mechanically Assisted Circulatory Support (J-MACS) is a prospective registry designed to be harmonized with the Interagency Registry of Mechanically Assisted Circulatory Support (INTERMACS). Participation in J-MACS is mandatory for device manufacturers to meet the conditions of approval as well as for hospitals to obtain authorization for reimbursement from the national health insurance system. RESULTS: From June 2010 to April 2015, 476 patients were registered at 31 hospitals. Of these, analysis of primary VAD patients (n = 332) revealed that their overall 360-day survival was 91% (implantable 93%, extracorporeal 84%). CONCLUSIONS: This initial report from J-MACS focuses on patients' demographics, device types, survival, competing outcomes, adverse events and successful examples of system failure detection.


Assuntos
Insuficiência Cardíaca/cirurgia , Coração Auxiliar/estatística & dados numéricos , Sistema de Registros , Insuficiência Cardíaca/epidemiologia , Humanos , Japão/epidemiologia , Morbidade/tendências
12.
Semin Cell Dev Biol ; 69: 26-33, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28736206

RESUMO

BPAG1, also known as Dystonin or BP230, belongs to the plakin family of proteins, which has multiple cytoskeleton-binding domains. Several BPAG1 isoforms are produced by a single BPAG1 genomic locus using different promoters and exons. For example, BPAG1a, BPAG1b, and BPAG1e are predominantly expressed in the nervous system, muscle, and skin, respectively. Among BPAG1 isoforms, BPAG1e is well studied because it was first identified as an autoantigen in patients with bullous pemphigoid, an autoimmune skin disease. BPAG1e is a component of hemidesmosomes, the adhesion complexes that promote dermal-epidermal cohesion. In the nervous system, the role of BPAG1a is also well studied because disruption of BPAG1a results in a phenotype identical to that of Dystonia musculorum (dt) mutants, which show progressive motor disorder. However, the expression and function of BPAG1 in muscles is not well studied. The aim of this review is to provide an overview of and highlight some recent findings on the expression and function of BPAG1 in muscles, which can assist future studies designed to delineate the role and regulation of BPAG1 in the dt mouse phenotype and in human hereditary sensory and autonomic neuropathy type 6 (HSAN6).


Assuntos
Distonina/metabolismo , Músculo Esquelético/metabolismo , Músculo Liso/metabolismo , Miocárdio/metabolismo , Animais , Distonina/química , Distonina/genética , Humanos
14.
J Neurochem ; 142(6): 886-900, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28608461

RESUMO

Phenotypic development of neocortical GABA neurons is highly plastic and promoted by various neurotrophic factors such as neuregulin-1. A subpopulation of GABA neurons expresses not only neuregulin receptor (ErbB4) but also epidermal growth factor (EGF) receptor (ErbB1) during development, but the neurobiological action of EGF on this cell population is less understood than that of neuregulin-1. Here, we examined the effects of exogenous EGF on immature GABA neurons both in culture and in vivo and also explored physiological consequences in adults. We prepared low density cultures from the neocortex of rat embryos and treated neocortical neurons with EGF. EGF decreased protein levels of glutamic acid decarboxylases (GAD65 and GAD67), and EGF influences on neuronal survival and glial proliferation were negligible or limited. The EGF treatment also diminished the frequency of miniature inhibitory postsynaptic currents (mIPSCs). In vivo administration of EGF to mouse pups reproduced the above GABAergic phenomena in neocortical culture. In EGF-injected postnatal mice, GAD- and parvalbumin-immunoreactivities were reduced in the frontal cortex. In addition, postnatal EGF treatment decreased mIPSC frequency in, and the density of, GABAergic terminals on pyramidal cells. Although these phenotypic influences on GABA neurons became less marked during development, it later resulted in the reduced ß- and γ-powers of sound-evoked electroencephalogram in adults, which is regulated by parvalbumin-positive GABA neurons and implicated in the schizophrenia pathophysiology. These findings suggest that, in contrast to the ErbB4 ligand of neuregulin-1, the ErbB1 ligand of EGF exerts unique maturation-attenuating influences on developing cortical GABAergic neurons.

15.
Front Neural Circuits ; 11: 14, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28293178

RESUMO

The auditory thalamus and auditory cortex (AC) are pivotal structures in the central auditory system. However, the thalamocortical mechanisms of processing sounds are largely unknown. Investigation of this process benefits greatly from the use of mice because the mouse is a powerful animal model in which various experimental techniques, especially genetic tools, can be applied. However, the use of mice has been limited in auditory research, and thus even basic anatomical knowledge of the mouse central auditory system has not been sufficiently collected. Recently, optical imaging combined with morphological analyses has enabled the elucidation of detailed anatomical properties of the mouse auditory system. These techniques have uncovered fine AC maps with multiple frequency-organized regions, each of which receives point-to-point thalamocortical projections from different origins inside the lemniscal auditory thalamus, the ventral division of the medial geniculate body (MGv). This precise anatomy now provides a platform for physiological research. In this mini review article, we summarize these recent achievements that will facilitate physiological investigations in the mouse auditory system.


Assuntos
Córtex Auditivo/anatomia & histologia , Corpos Geniculados/anatomia & histologia , Vias Neurais/anatomia & histologia , Animais , Córtex Auditivo/fisiologia , Corpos Geniculados/fisiologia , Camundongos , Vias Neurais/fisiologia
16.
Neurosci Lett ; 637: 26-30, 2017 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-27914952

RESUMO

Amid recent amendment of delineation of a mouse auditory cortical map, a caudal auditory field, originally defined as the primary auditory cortex (AI), was divided into the AI and dorsomedial field (DM), based on distinct high frequency areas. A low frequency area was not previously established in the DM because responses to low frequency tones were weak in this area. This may lead to the misconception that the DM is an atypical region that lacks a low frequency band. In the current study, we confirmed that the DM has a low frequency area that is completely independent from the AI. First, we conducted flavoprotein fluorescence imaging with improved signal to noise ratio and revealed the presence of two separated low frequency areas in the AI and DM. Next, we injected a retrograde neural tracer along the tonotopic axis of the AI or DM to reveal the thalamic origins in the ventral division of the medial geniculate body (MGv). We found that neurons projecting to low frequency areas of the AI and DM occupied different locations within the MGv and mutually independent topographic organizations consisting of thalamic neurons projecting to the AI or DM. These results indicate that the AI and DM have distinct low frequency areas with distinct thalamic projections from the MGv. Our findings reaffirm that the AI and DM should be regarded as independent regions in the mouse auditory cortex.


Assuntos
Córtex Auditivo/fisiologia , Vias Auditivas/fisiologia , Corpos Geniculados/fisiologia , Neurônios/fisiologia , Tálamo/fisiologia , Estimulação Acústica/métodos , Animais , Processamento de Imagem Assistida por Computador/métodos , Masculino , Camundongos Endogâmicos C57BL
17.
Neurobiol Dis ; 96: 271-283, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27693510

RESUMO

We identified a novel spontaneous mutant mouse showing motor symptoms that are similar to those of the dystonia musculorum (dt) mouse. The observations suggested that the mutant mice inherited the mild dt phenotype as an autosomal recessive trait. Linkage analysis showed that the causative gene was located near D1Mit373 and D1Mit410 microsatellite markers on chromosome 1, which are close to the dystonin (Dst) gene locus. To investigate whether Dst is the causative gene of the novel mutant phenotype, we crossed the mutant with Dst gene trap (DstGt) mice. Compound heterozygotes showed a typical dt phenotype with sensory degeneration and progressive motor symptoms. DNA sequencing analysis identified a nonsense mutation within the spectrin repeats of the plakin domain. The novel mutant allele was named dt23Rbrc. Motor abnormalities in homozygous dt23Rbrc/dt23Rbrc mice are not as severe as homozygous DstGt/DstGt mice. Histological analyses showed abnormal neurofilament (NF) accumulation in the nervous system of homozygous dt23Rbrc/dt23Rbrc mice, which is characteristic of the dt phenotype. We mapped the distribution of abnormal NF-accumulated neurons in the brain and found that they were located specifically in the brainstem, spinal cord, and in regions such as the vestibular nucleus, reticular nucleus, and red nucleus, which are implicated in posture and motor coordination pathways. The quantification of abnormal NF accumulation in the cytoplasm and spheroids (axons) of neurons showed that abnormal NF immunoreactivity was lower in homozygous dt23Rbrc/dt23Rbrc mice than in homozygous DstGt/DstGt mice. Therefore, we have identified a novel hypomorphic allele of dt, which causes histological abnormalities in the central nervous system that may account for the abnormal motor phenotype. This novel spontaneously occurring mutant may become a good model of hereditary sensory and autonomic neuropathy type 6, which is caused by mutations in the human DST gene.


Assuntos
Distúrbios Distônicos/complicações , Distúrbios Distônicos/genética , Distonina/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Transtornos Heredodegenerativos do Sistema Nervoso/etiologia , Repetições de Microssatélites/genética , Fatores Etários , Animais , Animais Recém-Nascidos , Cromossomos Humanos Par 1/genética , Distúrbios Distônicos/patologia , Distonina/metabolismo , Potencial Evocado Motor/genética , Comportamento Exploratório/fisiologia , Genótipo , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Transtornos Heredodegenerativos do Sistema Nervoso/patologia , Humanos , Filamentos Intermediários/genética , Filamentos Intermediários/metabolismo , Filamentos Intermediários/ultraestrutura , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes Neurológicos , Atividade Motora/genética , Neurônios/fisiologia , Neurônios/ultraestrutura , Reflexo de Endireitamento/genética , Percepção Espacial/fisiologia
18.
Ann Neurol ; 80(4): 554-65, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27490250

RESUMO

OBJECTIVE: To clarify the histopathological alterations of microglia in the brains of patients with hereditary diffuse leukoencephalopathy with spheroids (HDLS) caused by mutations of the gene encoding the colony stimulating factor-1 receptor (CSF-1R). METHODS: We examined 5 autopsied brains and 1 biopsy specimen from a total of 6 patients with CSF-1R mutations. Detailed immunohistochemical, biochemical, and ultrastructural features of microglia were examined, and quantitative analyses were performed. RESULTS: In layers 3 to 4 of the frontal cortex in HDLS brains, microglia showed relatively uniform and delicate morphology, with thin and winding processes accompanying knotlike structures, and significantly smaller areas of Iba1 immunoreactivity and lower numbers of Iba1-positive cells were evident in comparison with control brains. On the other hand, in layers 5 to 6 and the underlying white matter, microglia were distributed unevenly; that is, in some areas they had accumulated densely, whereas in others they were scattered. Immunoblot analyses of microglia-associated proteins, including CD11b and DAP12, revealed that HDLS brains had significantly lower amounts of these proteins than diseased controls, although Ki-67-positive proliferative microglia were not reduced. Ultrastructurally, the microglial cytoplasm and processes in HDLS showed vesiculation of the rough endoplasmic reticulum and disaggregated polyribosomes, indicating depression of protein synthesis. On the other hand, macrophages were immunonegative for GLUT-5 or P2ry12, indicating that they were derived from bone marrow. INTERPRETATION: The pathogenesis of HDLS seems to be associated with microglial vulnerability and morphological alterations. Ann Neurol 2016;80:554-565.


Assuntos
Córtex Cerebelar/patologia , Lobo Frontal/patologia , Leucoencefalopatias/patologia , Microglia/patologia , Substância Branca/patologia , Autopsia , Biópsia , Humanos , Leucoencefalopatias/metabolismo , Microglia/ultraestrutura , Receptor de Fator Estimulador de Colônias de Macrófagos/genética
19.
Acta Neuropathol Commun ; 4(1): 61, 2016 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-27338935

RESUMO

Frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) are types of major TDP-43 (43-kDa TAR DNA-binding protein) proteinopathy. Cortical TDP-43 pathology has been analyzed in detail in cases of FTLD-TDP, but is still unclear in cases of ALS. We attempted to clarify the cortical and subcortical TDP-43 pathology in Japanese cases of sporadic ALS (n = 96) using an antibody specific to phosphorylated TDP-43 (pTDP-43). The cases were divided into two groups: those without pTDP-43-positive neuronal cytoplasmic inclusions in the hippocampal dentate granule cells (Type 1, n = 63), and those with such inclusions (Type 2, n = 33). Furthermore, the Type 2 cases were divided into two subgroups based on semi-quantitative estimation of pTDP-43-positive dystrophic neurites (DNs) in the temporal neocortex: Type 2a (accompanied by no or few DNs, n = 22) and Type 2b (accompanied by abundant DNs, n = 11). Clinico-pathologic analysis revealed that cognitive impairment was a feature in patients with Type 2a and Type 2b, but not in those with Type 1, and that importantly, Type 2b is a distinct subtype characterized by a poor prognosis despite the less severe loss of lower motor neurons, the unusual subcortical dendrospinal pTDP-43 pathology, and more prominent glial involvement in cortical pTDP-43 pathology than other two groups. Considering the patient survival time and severity of motor neuron loss in each group, transition from Type 1 to Type 2, or from Type 2a to Type 2b during the disease course appeared unlikely. Therefore, each of these three groups was regarded as an independent subtype.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Proteínas de Ligação a DNA/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Esclerose Amiotrófica Lateral/classificação , Esclerose Amiotrófica Lateral/psicologia , Proteína C9orf72 , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Imuno-Histoquímica , Hibridização In Situ , Corpos de Inclusão/metabolismo , Corpos de Inclusão/patologia , Masculino , Pessoa de Meia-Idade , Mutação , Neurônios/metabolismo , Neurônios/patologia , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Fenótipo , Prognóstico , Proteínas/genética
20.
Sci Rep ; 6: 22315, 2016 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-26924462

RESUMO

Optical imaging studies have recently revealed the presence of multiple auditory cortical regions in the mouse brain. We have previously demonstrated, using flavoprotein fluorescence imaging, at least six regions in the mouse auditory cortex, including the anterior auditory field (AAF), primary auditory cortex (AI), the secondary auditory field (AII), dorsoanterior field (DA), dorsomedial field (DM), and dorsoposterior field (DP). While multiple regions in the visual cortex and somatosensory cortex have been annotated and consolidated in recent brain atlases, the multiple auditory cortical regions have not yet been presented from a coronal view. In the current study, we obtained regional coordinates of the six auditory cortical regions of the C57BL/6 mouse brain and illustrated these regions on template coronal brain slices. These results should reinforce the existing mouse brain atlases and support future studies in the auditory cortex.


Assuntos
Córtex Auditivo/fisiologia , Mapeamento Encefálico , Imageamento Tridimensional , Imagem Óptica , Animais , Flavoproteínas/genética , Flavoproteínas/metabolismo , Processamento de Imagem Assistida por Computador , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Imagem Óptica/métodos
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