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1.
J Periodontal Res ; 59(3): 542-551, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38146226

RESUMO

BACKGROUND AND OBJECTIVE: Efferocytosis is a process whereby macrophages remove apoptotic cells, such as neutrophils, that have accumulated in tissues, which is required for resolution of inflammation. Efferocytosis is impaired in individuals with increasing age and in those with various systemic diseases. Recently, efferocytosis has been reported to be related to the pathogenesis and progression of periodontitis, and enhancement of efferocytosis, especially in the subjects with impaired efferocytosis, was suggested to lead to periodontitis prevention and care. Various anti-inflammatory ingredients are used in oral care products, but their effect on efferocytosis is unclear. Here, we aimed to identify ingredients contained in oral care products that are effective for efferocytosis regulation. METHODS: The ability of dead cells to induce inflammation in human gingival fibroblast (HGF) cells were evaluated by measuring IL-6 secretion. Six ingredients in oral care products used as anti-inflammatory agents were evaluated for their effect on efferocytosis using flow cytometry. The expression of various efferocytosis-related molecules, such as MERTK and LRP1 involved in recognition, and LXRα and ABCA1 that function in metabolism, were measured in RAW264.7 cells with or without ingredient treatment. Rac1 activity, which is related to the uptake of dead cells, was measured using the G-LISA kit. RESULTS: Dead cells elicited IL-6 secretion in HGF cells. Among the six ingredients, GK2 and hinokitiol enhanced efferocytosis activity. GK2 and hinokitiol significantly increased the expression of MERTK and LRP1, and also enhanced LXRα and ABCA1 expression after efferocytosis. Furthermore, they increased Rac1 activity in the presence of dead cells. CONCLUSION: Among the six ingredients tested, GK2 and hinokitiol promoted efferocytosis by regulating apoptotic cell recognition, uptake, and metabolism-related molecules. Efferocytosis upregulation may be one of the mechanisms of GK2 and hinokitiol in the treatment of inflammatory diseases, such as periodontitis.


Assuntos
Apoptose , Gengiva , Ácido Glicirrízico , Macrófagos , Monoterpenos , Fagocitose , Tropolona , Apoptose/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Humanos , Tropolona/análogos & derivados , Tropolona/farmacologia , Fagocitose/efeitos dos fármacos , Gengiva/citologia , Gengiva/metabolismo , Gengiva/efeitos dos fármacos , Ácido Glicirrízico/farmacologia , Monoterpenos/farmacologia , Camundongos , Animais , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Células RAW 264.7 , Anti-Inflamatórios/farmacologia , Interleucina-6/metabolismo , Células Cultivadas , Eferocitose
2.
J Toxicol Sci ; 48(12): 617-639, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38044124

RESUMO

Although toxicities of multiwalled carbon nanotube (MWCNT) have been found to be related with activities of macrophages phagocytosing the fibers, the exact relationship between macrophage population and pathogenesis of fibrosis and mesotheliomas induced by MWCNTs is largely unknown. CCL2-CCR2 axis, a major monocyte/macrophage infiltration route, is thought to be involved in not only acute inflammation but also the formation of tumor microenvironment. We therefore described a time-course of alteration of macrophage population in an attempt to clarify the contribution of the Ccr2 gene to mesotheliomagenesis. Wild-type (WT) C57BL/6 mice and Ccr2-knockout (KO) mice were intraperitoneally administered with MWNT-7 and were sequentially necropsied at 1, 7, 28, 90, and 245 day(s) after the injection. Peritoneal fibrosis was prominent in all MWCNT-treated mice, with a lower severity in the KO mice. No differences were observed in the incidences of neoplastic lesions of mesothelia between WT and KO mice. A flow cytometric analysis revealed that after gross disappearance of macrophages after MWCNT exposure, small peritoneal macrophages (SPMs) were exclusively refurbished by the CCR2-dependent route at day 1 (as Ly-6C+MHC class II- cells), followed by additional CCR2-independent routes (as Ly-6C-MHC class II- cells); i.e., the only route in KO mice; with a delay of 1-7 days. The SPMs derived from both routes appeared to differentiate into maturated cells as Ly-6C-MHC class II+, whose ratio increased in a time-dependent manner among the total SPM population. Additionally, most macrophages expressed M1-like features, but a small fraction of macrophages exhibited an M1/M2 mixed status in MWCNT-treated animals. Our findings demonstrate a long-persistent activation of the CCL2-CCR2 axis after MWCNT exposure and enable a better understanding of the participation and potential roles of SPMs in fibrous material-induced chronic toxicities.


Assuntos
Mesotelioma , Nanotubos de Carbono , Camundongos , Animais , Nanotubos de Carbono/toxicidade , Macrófagos Peritoneais , Peritônio , Camundongos Endogâmicos C57BL , Fibrose , Mesotelioma/induzido quimicamente , Mesotelioma/genética , Camundongos Knockout , Microambiente Tumoral
3.
Cell Rep ; 42(9): 113137, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37708022

RESUMO

As cerebellar granule cells (GCs) coordinate the formation of regular cerebellar networks during postnatal development, molecules in GCs are expected to be involved. Here, we test the effects of the knockdown (KD) of multiple epidermal growth factor-like domains protein 11 (MEGF11), which is a homolog of proteins mediating astrocytic phagocytosis but is substantially increased at the later developmental stages of GCs on cerebellar development. MEGF11-KD in GCs of developing mice results in abnormal cerebellar structures, including extensively ectopic Purkinje cell (PC) somas, and in impaired motor functions. MEGF11-KD also causes abnormally asynchronous synaptic release from GC axons, parallel fibers, before the appearance of abnormal cerebellar structures. Interestingly, blockade of this abnormal synaptic release restores most of the cerebellar structures. Thus, apart from phagocytic functions of its related homologs in astrocytes, MEGF11 in GCs promotes proper PC development and cerebellar network formation by regulating immature synaptic transmission.

4.
Nanomaterials (Basel) ; 13(14)2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37513116

RESUMO

Despite intensive toxicological studies of carbon nanotubes (CNTs) over the last two decades, only a few studies have demonstrated their pulmonary carcinogenicities in chronic animal experiments, and the underlying molecular mechanisms are still unclear. To obtain molecular insights into CNT-induced lung carcinogenicity, we performed a transcriptomic analysis using a set of lung tissues collected from rats in a 2-year study, in which lung tumors were induced by repeated intratracheal instillations of a multiwalled carbon nanotube, MWNT-7. The RNA-seq-based transcriptome identified a large number of significantly differentially expressed genes at Year 0.5, Year 1, and Year 2. Ingenuity Pathway Analysis revealed that macrophage-elicited signaling pathways such as phagocytosis, acute phase response, and Toll-like receptor signaling were activated throughout the experimental period. At Year 2, cancer-related pathways including ERBB signaling and some axonal guidance signaling pathways such as EphB4 signaling were perturbed. qRT-PCR and immunohistochemistry indicated that several key molecules such as Osteopontin/Spp1, Hmox1, Mmp12, and ERBB2 were markedly altered and/or localized in the preneoplastic lesions, suggesting their participation in the induction of lung cancer. Our findings support a scenario of inflammation-induced carcinogenesis and contribute to a better understanding of the molecular mechanism of MWCNT carcinogenicity.

5.
Front Mol Neurosci ; 16: 1236015, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37520428

RESUMO

The well-organized cerebellar structures and neuronal networks are likely crucial for their functions in motor coordination, motor learning, cognition, and emotion. Such cerebellar structures and neuronal networks are formed during developmental periods through orchestrated mechanisms, which include not only cell-autonomous programs but also interactions between the same or different types of neurons. Cerebellar granule cells (GCs) are the most numerous neurons in the brain and are generated through intensive cell division of GC precursors (GCPs) during postnatal developmental periods. While GCs go through their own developmental processes of proliferation, differentiation, migration, and maturation, they also play a crucial role in cerebellar development. One of the best-characterized contributions is the enlargement and foliation of the cerebellum through massive proliferation of GCPs. In addition to this contribution, studies have shown that immature GCs and GCPs regulate multiple factors in the developing cerebellum, such as the development of other types of cerebellar neurons or the establishment of afferent innervations. These studies have often found impairments of cerebellar development in animals lacking expression of certain molecules in GCs, suggesting that the regulations are mediated by molecules that are secreted from or present in GCs. Given the growing recognition of GCs as regulators of cerebellar development, this review will summarize our current understanding of cerebellar development regulated by GCs and molecules in GCs, based on accumulated studies and recent findings, and will discuss their potential further contributions.

6.
Commun Biol ; 6(1): 446, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-37095324

RESUMO

The long-standing hypothesis that synapses between mossy fibers (MFs) and cerebellar granule cells (GCs) are organized according to the origins of MFs and locations of GC axons, parallel fibers (PFs), is supported by recent findings. However, the mechanisms of such organized synaptic connections remain unknown. Here, using our technique that enabled PF location-dependent labeling of GCs in mice, we confirmed that synaptic connections of GCs with specific MFs originating from the pontine nucleus (PN-MFs) and dorsal column nuclei (DCoN-MFs) were gently but differentially organized according to their PF locations. We then found that overall MF-GC synaptic connectivity was biased in a way that dendrites of GCs having nearby PFs tended to connect with the same MF terminals, implying that the MF origin- and PF location-dependent organization is associated with the overall biased MF-GC synaptic connectivity. Furthermore, the development of PN-MFs preceded that of DCoN-MFs, which matches the developmental sequence of GCs that preferentially connect with each type of these MFs. Thus, our results revealed that overall MF-GC synaptic connectivity is biased in terms of PF locations, and suggested that such connectivity is likely the result of synaptic formation between developmental timing-matched partners.


Assuntos
Cerebelo , Fibras Musgosas Hipocampais , Camundongos , Animais , Sinapses
7.
J Chem Phys ; 157(23): 234705, 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36550047

RESUMO

This study provides experimental evidence for the following: (1) Excess minority carrier recombination at SiO2/Si interfaces is associated with O2 dissociative adsorption; (2) the x-ray induced enhancement of SiO2 growth is not caused by the band flattening resulting from the surface photovoltaic effect but by the electron-hole pair creation resulting from core level photoexcitation for the spillover of bulk Si electronic states toward the SiO2 layer; and (3) a metastable chemisorbed O2 species plays a decisive role in combining two types of the single- and double-step oxidation reaction loops. Based on experimental results, the unified Si oxidation reaction model mediated by point defect generation [S. Ogawa et al., Jpn. J. Appl. Phys., Part 1 59, SM0801 (2020)] is extended from the viewpoints of (a) the excess minority carrier recombination at the oxidation-induced vacancy site and (b) the trapping-mediated adsorption through the chemisorbed O2 species at the SiO2/Si interface.

8.
Part Fibre Toxicol ; 19(1): 38, 2022 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-35590372

RESUMO

BACKGROUND: A mounting number of studies have been documenting the carcinogenic potential of multiwalled carbon nanotubes (MWCNTs); however, only a few studies have evaluated the pulmonary carcinogenicity of MWCNTs in vivo. A 2-year inhalation study demonstrated that MWNT-7, a widely used MWCNT, was a pulmonary carcinogen in rats. In another 2-year study, rats administered MWNT-7 by intratracheal instillation at the beginning of the experimental period developed pleural mesotheliomas but not lung tumors. To obtain data more comparable with rats exposed to MWNT-7 by inhalation, we administered MWNT-7 to F344 rats by intratracheal instillation once every 4-weeks over the course of 2 years at 0, 0.125, and 0.5 mg/kg body weight, allowing lung burdens of MWNT-7 to increase over the entire experimental period, similar to the inhalation study. RESULTS: Absolute and relative lung weights were significantly elevated in both MWNT-7-treated groups. Dose- and time-dependent toxic effects in the lung and pleura, such as inflammatory, fibrotic, and hyperplastic lesions, were found in both treated groups. The incidences of lung carcinomas, lung adenomas, and pleural mesotheliomas were significantly increased in the high-dose group compared with the control group. The pleural mesotheliomas developed mainly at the mediastinum. No MWNT-7-related neoplastic lesions were noted in the other organs. Cytological and biochemical parameters of the bronchoalveolar lavage fluid (BALF) were elevated in both treated groups. The lung burden of MWNT-7 was dose- and time-dependent, and at the terminal necropsy, the average value was 0.9 and 3.6 mg/lung in the low-dose and high-dose groups, respectively. The number of fibers in the pleural cavity was also dose- and time-dependent. CONCLUSIONS: Repeated administration of MWNT-7 by intratracheal instillation over the 2 years indicates that MWNT-7 is carcinogenic to both the lung and pleura of rats, which differs from the results of the 2 carcinogenicity tests by inhalation or intratracheal instillation.


Assuntos
Neoplasias Pulmonares , Mesotelioma Maligno , Mesotelioma , Nanotubos de Carbono , Animais , Carcinógenos/toxicidade , Neoplasias Pulmonares/induzido quimicamente , Neoplasias Pulmonares/patologia , Mesotelioma/induzido quimicamente , Mesotelioma/patologia , Nanotubos de Carbono/toxicidade , Ratos , Ratos Endogâmicos F344
9.
Womens Health Rep (New Rochelle) ; 3(1): 335-343, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35415716

RESUMO

Objective: Hot flashes, a symptom of menopause, can decrease women's quality of life. Sympathetic nervous system activation has been identified as an important factor in the occurrence of hot flashes. Given that somatosensory stimulation of the oral cavity can affect autonomic nervous activity, we aimed to investigate the possibility that somatosensory stimulation of the gums (i.e., gum massage) could improve hot flashes. Materials and Methods: Nineteen women experiencing at least one hot flash per day were instructed to perform a gum massage on themselves before undertaking mental workload, using arithmetic task, and the frequency of hot flashes experienced during this task was measured. Changes in autonomic nervous activity were assessed based on heart rate variability. Results: Massage conditions promoted a significantly lower arithmetic task-induced hot flash frequency compared with nonmassage conditions (p < 0.05). During gum massage, the ratio between low and high frequency (LF/HF) values decreased significantly under massage conditions compared with nonmassage conditions (p < 0.01). During the arithmetic task, the gum massage-induced reduction in LF/HF, which changed from baseline, was significantly correlated with the gum massage-induced reduction in hot flash frequency. Conclusions: The results of this study indicate that gum massage can reduce the subjective frequency of hot flashes over a certain period under mental workload. Our study also indicates that gum massage can potentially decrease sympathetic nerve activity, which is known to be involved in the occurrence of hot flashes.Clinical Trial Registration number 328 (the institutional review board of Lion Corporation).

10.
Elife ; 112022 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-35156922

RESUMO

Although cerebellar alterations have been implicated in stress symptoms, the exact contribution of the cerebellum to stress symptoms remains to be elucidated. Here, we demonstrated the crucial role of cerebellar neurons projecting to the ventral tegmental area (VTA) in the development of chronic stress-induced behavioral alterations in mice. Chronic chemogenetic activation of inhibitory Purkinje cells in crus I suppressed c-Fos expression in the DN and an increase in immobility in the tail suspension test or forced swimming test, which were triggered by chronic stress application. The combination of adeno-associated virus-based circuit mapping and electrophysiological recording identified network connections from crus I to the VTA via the dentate nucleus (DN) of the deep cerebellar nuclei. Furthermore, chronic inhibition of specific neurons in the DN that project to the VTA prevented stressed mice from showing such depression-like behavior, whereas chronic activation of these neurons alone triggered behavioral changes that were comparable with the depression-like behaviors triggered by chronic stress application. Our results indicate that the VTA-projecting cerebellar neurons proactively regulate the development of depression-like behavior, raising the possibility that cerebellum may be an effective target for the prevention of depressive disorders in human.


Assuntos
Cerebelo/citologia , Depressão , Neurônios/metabolismo , Estresse Fisiológico , Área Tegmentar Ventral/fisiologia , Animais , Comportamento Animal , Feminino , Interneurônios/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR
11.
Nat Commun ; 12(1): 5837, 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34611167

RESUMO

Ryugu is a carbonaceous rubble-pile asteroid visited by the Hayabusa2 spacecraft. Small rubble pile asteroids record the thermal evolution of their much larger parent bodies. However, recent space weathering and/or solar heating create ambiguities between the uppermost layer observable by remote-sensing and the pristine material from the parent body. Hayabusa2 remote-sensing observations find that on the asteroid (162173) Ryugu both north and south pole regions preserve the material least processed by space weathering, which is spectrally blue carbonaceous chondritic material with a 0-3% deep 0.7-µm band absorption, indicative of Fe-bearing phyllosilicates. Here we report that spectrally blue Ryugu's parent body experienced intensive aqueous alteration and subsequent thermal metamorphism at 570-670 K (300-400 °C), suggesting that Ryugu's parent body was heated by radioactive decay of short-lived radionuclides possibly because of its early formation 2-2.5 Ma. The samples being brought to Earth by Hayabusa2 will give us our first insights into this epoch in solar system history.

12.
PLoS One ; 16(9): e0257705, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34534255

RESUMO

SARS-CoV-2 enters host cells when the viral spike protein is cleaved by transmembrane protease serine 2 (TMPRSS2) after binding to the host angiotensin-converting enzyme 2 (ACE2). Since ACE2 and TMPRSS2 are expressed in the tongue and gingival mucosa, the oral cavity is a potential entry point for SARS-CoV-2. This study evaluated the inhibitory effects of general ingredients of toothpastes and mouthwashes on the spike protein-ACE2 interaction and the TMPRSS2 protease activity using an in vitro assay. Both assays detected inhibitory effects of sodium tetradecene sulfonate, sodium N-lauroyl-N-methyltaurate, sodium N-lauroylsarcosinate, sodium dodecyl sulfate, and copper gluconate. Molecular docking simulations suggested that these ingredients could bind to inhibitor-binding site of ACE2. Furthermore, tranexamic acid exerted inhibitory effects on TMPRSS2 protease activity. Our findings suggest that these toothpaste and mouthwash ingredients could help prevent SARS-CoV-2 infection.


Assuntos
COVID-19/prevenção & controle , Antissépticos Bucais/farmacologia , Higiene Bucal/métodos , SARS-CoV-2/efeitos dos fármacos , Cremes Dentais/farmacologia , Internalização do Vírus/efeitos dos fármacos , Enzima de Conversão de Angiotensina 2/imunologia , Humanos , Serina Endopeptidases/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia
13.
Mol Brain ; 14(1): 63, 2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33789707

RESUMO

Cerebellar granule cells (GCs) relay mossy fiber (MF) inputs to Purkinje cell dendrites via their axons, the parallel fibers (PFs), which are individually located at a given sublayer of the molecular layer (ML). Although a certain degree of heterogeneity among GCs has been recently reported, variability of GC responses to MF inputs has never been associated with their most notable structural variability, location of their projecting PFs in the ML. Here, we utilize an adeno-associated virus (AAV)-mediated labeling technique that enables us to categorize GCs according to the location of their PFs, and compare the Ca2+ responses to MF stimulations between three groups of GCs, consisting of either GCs having PFs at the deep (D-GCs), middle (M-GCs), or superficial (S-GCs) sublayer. Our structural analysis revealed that there was no correlation between position of GC soma in the GC layer and location of its PF in the ML, confirming that our AAV-mediated labeling was important to test the projection-dependent variability of the Ca2+ responses in GCs. We then found that the Ca2+ responses of D-GCs differed from those of M-GCs. Pharmacological experiments implied that the different Ca2+ responses were mainly attributable to varied distributions of GABAA receptors (GABAARs) at the synaptic and extrasynaptic regions of GC dendrites. In addition to GABAAR distributions, amounts of extrasynaptic NMDA receptors appear to be also varied, because Ca2+ responses were different between D-GCs and M-GCs when glutamate spillover was enhanced. Whereas the Ca2+ responses of S-GCs were mostly equivalent to those of D-GCs and M-GCs, the blockade of GABA uptake resulted in larger Ca2+ responses in S-GCs compared with D-GCs and M-GCs, implying existence of mechanisms leading to more excitability in S-GCs with increased GABA release. Thus, this study reveals MF stimulation-mediated non-uniform Ca2+ responses in the cerebellar GCs associated with the location of their PFs in the ML, and raises a possibility that combination of inherent functional variability of GCs and their specific axonal projection contributes to the information processing through the GCs.


Assuntos
Sinalização do Cálcio/fisiologia , Córtex Cerebelar/citologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Transmissão Sináptica/fisiologia , 2-Amino-5-fosfonovalerato/farmacologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Córtex Cerebelar/ultraestrutura , Dependovirus/genética , Genes Reporter , Vetores Genéticos , Camundongos , Fibras Nervosas/fisiologia , Células de Purkinje/fisiologia , Receptores de GABA-A/genética , Receptores de GABA-A/fisiologia
14.
Cancer Sci ; 112(6): 2185-2198, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33665882

RESUMO

A rat model of mesothelioma development by peritoneal injection of multiwalled carbon nanotube (MWCNT) has been established and found to be useful to understand the mechanisms underlying fibrous particles-associated carcinogenesis. Its detailed histological sequence, however, remains largely obscure. We therefore aimed to assess the time-course of mesothelioma development by MWCNT and evaluate a set of lipoprotein-related molecules as potential mechanism-based biomarkers for the phenomenon. Male Fischer 344 rats were injected intraperitoneally (ip) with MWCNT (MWNT-7) at 1 mg/kg body weight, and necropsied at 8, 16, 24, 32, or 42 wk after injection. For biochemical analyses of the lipoprotein-related molecules, more samples, including severe mesothelioma cases, were obtained from 2 other carcinogenicity tests. Histologically, in association with chronic inflammation, mesothelial proliferative lesions appeared at c. Wk-24. Before and at the beginning of the tumor development, a prominent infiltration of CD163-positive cells was seen near mesothelial cells. The histological pattern of early mesothelioma was not a papillary structure, but was a characteristic structure with a spherical appearance, composed of the mesothelioma cells in the surface area that were underlain by connective tissue-like cells. Along with the progression, mesotheliomas started to show versatile histological subtypes. Serum levels of apolipoprotein A-I and A-IV, and a ratio of HDL cholesterol to total cholesterol were inversely correlated with mesothelioma severity. Overall, the detailed histological sequence of mesotheliomagenesis by MWCNT is demonstrated, and indicated that the altered profile of apolipoproteins may be involved in its underlying mechanisms.


Assuntos
Apolipoproteínas/metabolismo , Carcinógenos/toxicidade , Mesotelioma/patologia , Nanotubos de Carbono/toxicidade , Animais , Líquido Ascítico/metabolismo , Biomarcadores Tumorais/metabolismo , Carcinogênese , Colesterol/metabolismo , Masculino , Mesotelioma/induzido quimicamente , Mesotelioma/metabolismo , Ratos , Ratos Endogâmicos F344
15.
Neuroscience ; 462: 44-55, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-32502568

RESUMO

The cerebellum forms regular neural network structures consisting of a few major types of neurons, such as Purkinje cells, granule cells, and molecular layer interneurons, and receives two major inputs from climbing fibers and mossy fibers. Its regular structures consist of three well-defined layers, with each type of neuron designated to a specific location and forming specific synaptic connections. During the first few weeks of postnatal development in rodents, the cerebellum goes through dynamic changes via proliferation, migration, differentiation, synaptogenesis, and maturation, to create such a network structure. The development of this organized network structure presumably relies on the communication between developing elements in the network, including not only individual neurons, but also their dendrites, axons, and synapses. Therefore, it is reasonable that extracellular signaling via synaptic transmission, secreted molecules, and cell adhesion molecules, plays important roles in cerebellar network development. Although it is not yet clear as to how overall cerebellar development is orchestrated, there is indeed accumulating lines of evidence that extracellular signaling acts toward the development of individual elements in the cerebellar networks. In this article, we introduce what we have learned from many studies regarding the extracellular signaling required for cerebellar network development, including our recent study suggesting the importance of unbiased synaptic inputs from parallel fibers.


Assuntos
Cerebelo , Células de Purkinje , Axônios , Neurônios , Sinapses
16.
Front Neuroanat ; 15: 759948, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34975418

RESUMO

The cerebellum has a long history in terms of research on its network structures and motor functions, yet our understanding of them has further advanced in recent years owing to technical developments, such as viral tracers, optogenetic and chemogenetic manipulation, and single cell gene expression analyses. Specifically, it is now widely accepted that the cerebellum is also involved in non-motor functions, such as cognitive and psychological functions, mainly from studies that have clarified neuronal pathways from the cerebellum to other brain regions that are relevant to these functions. The techniques to manipulate specific neuronal pathways were effectively utilized to demonstrate the involvement of the cerebellum and its pathways in specific brain functions, without altering motor activity. In particular, the cerebellar efferent pathways that have recently gained attention are not only monosynaptic connections to other brain regions, including the periaqueductal gray and ventral tegmental area, but also polysynaptic connections to other brain regions, including the non-primary motor cortex and hippocampus. Besides these efferent pathways associated with non-motor functions, recent studies using sophisticated experimental techniques further characterized the historically studied efferent pathways that are primarily associated with motor functions. Nevertheless, to our knowledge, there are no articles that comprehensively describe various cerebellar efferent pathways, although there are many interesting review articles focusing on specific functions or pathways. Here, we summarize the recent findings on neuronal networks projecting from the cerebellum to several brain regions. We also introduce various techniques that have enabled us to advance our understanding of the cerebellar efferent pathways, and further discuss possible directions for future research regarding these efferent pathways and their functions.

17.
Nature ; 579(7800): 518-522, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32214245

RESUMO

Carbonaceous (C-type) asteroids1 are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites2,3 and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth's atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR)4 onboard the spacecraft Hayabusa25, indicating that the asteroid's boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m-2 s-0.5 K-1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites6 and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect7,8. We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites6. These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity9 of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies10.

18.
Cell Rep ; 28(11): 2939-2954.e5, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509753

RESUMO

Neuronal activity is believed to be important for brain development; however, it remains unclear as to how spatiotemporal distributions of synaptic excitation contribute to neural network formation. Bifurcated axons of cerebellar granule cells, parallel fibers (PFs), are made in an orderly inside-out manner during postnatal development. In this study, we induced a blockade of neurotransmitter release from specific bundles of developing PFs and tested the effects of biased PF inputs on cerebellar development. The blockade of different layers of PFs at different developmental times results in varying degrees of abnormal cerebellar development. Furthermore, cerebellar network abnormalities are not restored when PF inputs are restored in adulthood and, hence, result in motor dysfunction. We thus conclude that spatiotemporally unbiased synaptic transmission from sequentially developed PFs is crucial for cerebellar network formation and motor function, supporting the idea that unbiased excitatory synaptic transmission is crucial for network formation.


Assuntos
Axônios/efeitos dos fármacos , Cerebelo/crescimento & desenvolvimento , Cerebelo/fisiopatologia , Neocórtex/fisiopatologia , Células de Purkinje/patologia , Transmissão Sináptica/efeitos dos fármacos , Animais , Axônios/metabolismo , Axônios/fisiologia , Cerebelo/citologia , Cerebelo/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Locomoção/efeitos dos fármacos , Locomoção/fisiologia , Camundongos , Camundongos Transgênicos , Neocórtex/citologia , Neocórtex/efeitos dos fármacos , Neurogênese/efeitos dos fármacos , Neurogênese/fisiologia , Células de Purkinje/citologia , Células de Purkinje/efeitos dos fármacos , Células de Purkinje/metabolismo , Sinapses/fisiologia , Transmissão Sináptica/fisiologia , Toxina Tetânica/toxicidade , Fatores de Tempo
19.
J Neurol Sci ; 404: 11-15, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31323516

RESUMO

Robot-assisted gait training following acute stroke could allow patients with severe disability to receive a high dosage and intensity of gait training compared with conventional physical therapy (CP). However, given the limited data on gauging the efficacy of Hybrid Assistive Limb (HAL) on gait training in patients with acute stroke, we aimed to evaluate several outcome measures following gait training with HAL. Patients with first-ever stroke, who required a walking aid and were able to start gait training within 1 week of stroke onset were included in the current study. Patients were assigned to either the CP or HAL group. Outcome measures were collected at baseline, and at the 2nd (at 2-6 weeks), and 3rd (at 3-5 months) assessments. All patients underwent physical therapy until the 3rd assessment; patients in the HAL group underwent gait training using HAL until the 2nd assessment. Thirty-seven patients (19 from CP and 18 from HAL, median age = 69 years) completed the study. At the 2nd assessment, the total Functional Independence Measure (FIM) score was higher in the HAL group than in the CP group (90.1 vs. 79.0, p = 0.042). In conclusion, the FIM scale could be used to identify responsiveness to acute stroke rehabilitation using HAL.


Assuntos
Transtornos Neurológicos da Marcha/reabilitação , Robótica/métodos , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/terapia , Idoso , Terapia por Exercício/instrumentação , Terapia por Exercício/métodos , Feminino , Transtornos Neurológicos da Marcha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Robótica/instrumentação , Acidente Vascular Cerebral/epidemiologia , Reabilitação do Acidente Vascular Cerebral/instrumentação
20.
Medicina (Kaunas) ; 55(7)2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31252680

RESUMO

Background and objectives: It is well-known that lifestyle is closely associated with psychological distress in many elderly subjects. However, the effect of intervention with physical activity and/or sleeping on psychological distress has not been fully discussed. The purpose of this cross-sectional study was to investigate the relationships between physical activity, sleeping time, and psychological distress in community-dwelling elderly Japanese subjects. Materials and Methods: A total of 108 elderly Japanese (31 men and 77 women) subjects were enrolled in this cross-sectional study. Psychological distress was evaluated using the K6 questionnaire. Physical activity, including sedentary behavior, was measured using a tri-accelerometer. Sleeping time was evaluated using a self-reported questionnaire. Results: The median of the K6 scores was 1.0 (0-18), and the sedentary behavior (%) and walking time (minutes/day) were 57.2 ± 10.7 and 80.7 (17.9-222.4), respectively. Sleeping time was negatively correlated with psychological distress. In addition, multiple linear regression showed that walking time and sleeping time were important factors for psychological distress, even after adjusting for confounding factors. Conclusions: These results suggest that increased walking time and sleeping time may be beneficial for reducing psychological distress in community-dwelling elderly Japanese subjects.


Assuntos
Exercício Físico/fisiologia , Sono/fisiologia , Estresse Psicológico/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Vida Independente/estatística & dados numéricos , Japão , Masculino , Autorrelato , Inquéritos e Questionários , Fatores de Tempo
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