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1.
EMBO J ; 39(6): e102214, 2020 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-32030804

RESUMO

Spinal cord microglia contribute to nerve injury-induced neuropathic pain. We have previously demonstrated that toll-like receptor 2 (TLR2) signaling is critical for nerve injury-induced activation of spinal cord microglia, but the responsible endogenous TLR2 agonist has not been identified. Here, we show that nerve injury-induced upregulation of sialyltransferase St3gal2 in sensory neurons leads to an increase in expression of the sialylated glycosphingolipid, GT1b. GT1b ganglioside is axonally transported to the spinal cord dorsal horn and contributes to characteristics of neuropathic pain such as mechanical and thermal hypersensitivity. Spinal cord GT1b functions as an TLR2 agonist and induces proinflammatory microglia activation and central sensitization. Pharmacological inhibition of GT1b synthesis attenuates nerve injury-induced spinal cord microglia activation and pain hypersensitivity. Thus, the St3gal2-GT1b-TLR2 axis may offer a novel therapeutic target for the treatment of neuropathic pain.


Assuntos
Gangliosídeos/metabolismo , Neuralgia/terapia , Traumatismos dos Nervos Periféricos/terapia , Transdução de Sinais , Receptor 2 Toll-Like/agonistas , Animais , Gangliosídeos/antagonistas & inibidores , Regulação da Expressão Gênica , Inflamação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Neuralgia/etiologia , Traumatismos dos Nervos Periféricos/etiologia , Ratos , Ratos Sprague-Dawley , Células Receptoras Sensoriais , Sialiltransferases/genética , Sialiltransferases/metabolismo , Medula Espinal/metabolismo , Receptor 2 Toll-Like/metabolismo
2.
Stroke ; 54(2): 575-586, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36490365

RESUMO

BACKGROUND: The migration of oligodendrocyte precursor cells (OPC) is a key process of remyelination, which is essential for the treatment of white matter stroke. This study aimed to investigate the role of HMGB1 (high mobility group box 1), a damage-associated molecular pattern released from dying oligodendrocytes, as an autocrine chemoattractant that promotes OPC migration. METHODS: The migratory capacity of primary cultured OPCs was measured using the Boyden chamber assay. The downstream pathway of HMGB1-mediated OPC migration was specified by siRNA-induced knockdown or pharmacological blockade of TLR2 (toll-like receptor 2), RAGE (receptor for advanced glycation end product), Src, ERK1/2 (extracellular signal-regulated kinase1/2), and FAK (focal adhesion kinase). Conditioned media were collected from oxygen-glucose deprivation-treated oligodendrocytes, and the impact on OPC migration was assessed. Lesion size and number of intralesional Olig2(+) cells were analyzed in an in vivo model of white matter stroke with N5-(1-iminoethyl)-L-ornithine (L-NIO). RESULTS: HMGB1 treatment promoted OPC migration. HMGB1 antagonism reversed such effects to untreated levels. Among the candidates for the downstream signal of HMGB1-mediated migration, the knockdown of TLR2 rather than that of RAGE attenuated the migration-promoting effect of HMGB1. Further specification of the HMGB1-TLR2 axis revealed that the phosphorylation of ERK1/2 and its downstream molecule FAK, rather than of Src, was decreased in TLR2-knockdown OPCs, and pharmacological inhibition of ERK1/2 and FAK led to decreased OPC migration. Oxygen-glucose deprivation-conditioned media promoted OPC migration, suggesting the autocrine chemoattractant function of HMGB1. In vivo, TLR2(-/-)-mice showed lesser intralesional Olig2(+) cells compared to wild-type controls in response to L-NIO induced ischemic injury regardless of HMGB1 administration. CONCLUSIONS: HMGB1, through the TLR2-ERK1/2-FAK axis, functions as an autocrine chemoattractant to promote OPC migration, which is an initial and indispensable step in remyelination. Thus, a novel treatment strategy for white matter stroke based on the HMGB1-TLR2 axis in the oligodendrocyte lineage could be feasible.


Assuntos
Proteína HMGB1 , Acidente Vascular Cerebral , Substância Branca , Camundongos , Animais , Receptor 2 Toll-Like/metabolismo , Substância Branca/patologia , Linhagem da Célula , Proteína HMGB1/metabolismo , Meios de Cultivo Condicionados/metabolismo , Oligodendroglia/metabolismo , Acidente Vascular Cerebral/patologia
3.
J Neurosci ; 41(3): 446-460, 2021 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-33262248

RESUMO

Preconditioning peripheral nerve injury enhances the intrinsic growth capacity of DRGs sensory axons by inducing transcriptional upregulation of the regeneration-associated genes (RAGs). However, it is still unclear how preconditioning injury leads to the orchestrated induction of many RAGs. The present study identified Myc proto-oncogene as a transcriptional hub gene to regulate the expression of a distinct subset of RAGs in DRGs following the preconditioning injury. We demonstrated that c-MYC bound to the promoters of certain RAGs, such as Jun, Atf3, and Sprr1a, and that Myc upregulation following SNI preceded that of the RAGs bound by c-MYC. Marked DNA methylation of the Myc exon 3 sequences was implicated in the early transcriptional activation and accompanied by open histone marks. Myc deletion led to a decrease in the injury-induced expression of a distinct subset of RAGs, which were highly overlapped with the list of RAGs that were upregulated by Myc overexpression. Following dorsal hemisection spinal cord injury in female rats, Myc overexpression in DRGs significantly prevented the retraction of the sensory axons in a manner dependent on its downstream RAG, June Our results suggest that Myc plays a critical role in axon regeneration via its transcriptional activity to regulate the expression of a spectrum of downstream RAGs and subsequent effector molecules. Identification of more upstream hub transcription factors and the epigenetic mechanisms specific for individual hub transcription factors would advance our understanding of how the preconditioning injury induces orchestrated upregulation of RAGs.


Assuntos
Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Regeneração Nervosa/genética , Regeneração Nervosa/fisiologia , Traumatismos dos Nervos Periféricos/genética , Traumatismos dos Nervos Periféricos/fisiopatologia , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/fisiologia , Animais , Axônios/fisiologia , Metilação de DNA , Epigênese Genética/genética , Feminino , Gânglios Espinais/citologia , Gânglios Espinais/fisiologia , Neuritos , Células PC12 , Ratos , Ratos Sprague-Dawley , Células Receptoras Sensoriais/fisiologia
4.
Small ; 18(21): e2200326, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35285157

RESUMO

The widespread adoption of Li-ion batteries is currently limited by their unstable electrochemical performance and high flammability under mechanical deformation conditions and a relatively low energy density. Herein, high-energy-density lithium-sulfur (Li-S) batteries are developed for applications in next-generation flexible electronics and electric vehicles with long cruising distances. Freestanding high-S-loading carbon nanotubes cathodes are assembled with a phosphorus (P)-doped carbon interlayer coated on commercial separators. Strategies for the active materials and structural design of both the electrodes and separators are highly efficient for immobilizing the lithium polysulfides via multimodal capturing effects; they significantly improve the electrochemical performance in terms of the redox kinetics and cycling stability. The foldable Li-S cells show stable specific capacities of 850 mAh g-1 over 100 cycles, achieving high gravimetric and volumetric energy densities of 387 Wh kgcell -1 and 395 Wh Lcell -1 , respectively. The Li-S cells show highly durable mechanical flexibilities under severe deformation conditions without short circuit or failure. Finally, the Li-S battery is explored as a light-weight and flexible energy storage device aboard airplane drones to ensure at least fivefold longer flight times than traditional Li-ion batteries. Nanocarbon-based S cathodes and P-doped carbon interlayers offer a promising solution for commercializing rechargeable Li-S batteries.

5.
Glia ; 69(4): 1037-1052, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33300228

RESUMO

The brain has an intrinsic capacity to repair injury, but the specific mechanisms are largely unknown. In this study, we found that, despite their incipient death, damaged neurons play a key repair role with the help of monocytes infiltrated from blood. Monocytes phagocytosed damaged and/or dying neurons that expressed osteopontin (OPN), with possible subsequent activation of their inflammasome pathway, resulting in pyroptosis. During this process, monocytes released CD63-positive exosome-like vesicles containing OPN. Importantly, following the exosome-like vesicles, neuron and astrocyte processes elongated toward the injury core. In addition, exosomes prepared from the injured brain contained OPN, and enhanced neurite outgrowth of cultured neurons in an OPN-dependent manner. Thus, our results introduce the concept that neurons in the injured brain that are destined to die perceive the stressful condition and begin the regeneration processes through induction of OPN, ultimately executing the repair process with the help of monocytes recruited from the circulation.


Assuntos
Monócitos , Osteopontina , Encéfalo/metabolismo , Monócitos/metabolismo , Neurônios/metabolismo , Osteopontina/metabolismo , Fagocitose
6.
Opt Lett ; 46(7): 1608-1611, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33793499

RESUMO

We propose a simple two-channel mode-group-division-multiplexing (MGDM) system operating in the 0.8 µm region over the standard single-mode fiber (SSMF). For the cost-effectiveness, we implement its receiver by using only two photodetectors (PDs) [instead of three PDs required for the detection of the LP01,LP11a, and LP11b modes]. We then detect the signal carried by the LP01 mode by using a PD and a mode filter. On the other hand, the other signal carried by the LP11 mode group is detected by using another PD and a multiple-input single-output equalizer (i.e., by subtracting the signal carried by the LP01 mode from the multiplexed signal). For a demonstration, we transmit 2×28Gb/s MGDM on-off keying signal operating at 852.6 nm over 2.2 km of the SSMF by using the proposed technique. The results show that we can achieve the bit-error rate of <3.8×10-3 for both the LP01 and LP11 modes.

7.
Surg Endosc ; 35(10): 5836-5841, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34143290

RESUMO

BACKGROUND: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). We developed a robotic assistive traction device for flexible endoscopy and compared its safety and efficiency in ESD between experienced and novice endoscopists. METHODS: Robotic ESD was performed by experienced and novice endoscopist groups (n = 2, each). The outcomes included time to complete each ESD step, total procedure time, size of the dissected mucosa, rate of en bloc resection, and major adverse events. Furthermore, incision and dissection speeds were compared between groups. RESULTS: Sixteen gastric lesions were resected from nine live pigs. The submucosal incision speed was significantly faster in the expert group than in the novice group (P = 0.002). There was no significant difference in the submucosal dissection speed between the groups (P = 0.365). No complications were reported in either group. CONCLUSIONS: When the robot was assisting in the ESD procedure, the dissection speed improved significantly, especially in the novice surgeons. Our robotic device can provide simple, effective, and safe multidirectional traction during ESD.


Assuntos
Ressecção Endoscópica de Mucosa , Robótica , Animais , Dissecação , Estudos de Viabilidade , Suínos , Tração
8.
Glia ; 68(10): 2086-2101, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32176388

RESUMO

Monocyte-derived macrophages play a role in the repair of the injured brain. We previously reported that a deficiency of the Parkinson's disease (PD)-associated gene DJ-1 delays repair of brain injury produced by stereotaxic injection of ATP, a component of damage-associated molecular patterns. Here, we show that a DJ-1 deficiency attenuates monocyte infiltration into the damaged brain owing to a decrease in C-C motif chemokine ligand 2 (CCL2) expression in astrocytes. Like DJ-1-knockout (KO) mice, CCL2 receptor (CCR2)-KO mice showed defects in monocyte infiltration and delayed recovery of brain injury, as determined by 9.4 T magnetic resonance imaging analysis and immunostaining for tyrosine hydroxylase and glial fibrillary acid protein. Notably, transcriptome analyses showed that genes related to regeneration and synapse formation were similarly downregulated in injured brains of DJ-1-KO and CCR2-KO mice compared with the injured wild-type brain. These results indicate that defective astrogliosis in DJ-1-KO mice is associated with decreased CCL2 expression and attenuated monocyte infiltration, resulting in delayed repair of brain injury. Thus, delayed repair of brain injury could contribute to the development of PD. MAIN POINTS: A DJ-1 deficiency attenuates infiltration of monocytes owing to a decrease in CCL2 expression in astrocytes, which in turn led to delay in repair of brain injury.


Assuntos
Astrócitos/metabolismo , Lesões Encefálicas/metabolismo , Quimiocina CCL2/biossíntese , Monócitos/metabolismo , Proteína Desglicase DJ-1/deficiência , Animais , Astrócitos/patologia , Lesões Encefálicas/genética , Lesões Encefálicas/patologia , Quimiocina CCL2/antagonistas & inibidores , Quimiocina CCL2/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Monócitos/patologia , Proteína Desglicase DJ-1/genética
9.
Neurobiol Dis ; 134: 104672, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31707117

RESUMO

Ischemic white matter injuries underlie cognitive decline in the elderly and vascular dementia. Ischemia in the subcortical white matter is caused by chronic reduction of blood flow due to narrowing of small arterioles. However, it remains unclear how chronic ischemia leads to white matter pathology. We aimed to develop an in vitro model of ischemic white matter injury using organotypic slice cultures. Cultured cerebellar slices preserved fully myelinated white matter tracts that were amenable to chronic hypoxic insult. Prolonged hypoxia caused progressive morphological evidence of axonal degeneration with focal constrictions and swellings. In contrast, myelin sheaths and oligodendrocytes exhibited remarkable resilience to hypoxia. The cytoskeletal degradation of axons was accompanied by mitochondrial shortening and lysosomal activation. Multiple pharmacological manipulations revealed that the AMPA glutamate receptor, calpain proteolysis, and lysosomal proteases were independently implicated in hypoxia-induced axonal degeneration in our model. Thus, our in vitro model would be a novel experimental system to explore molecular mechanisms of ischemic white matter injury. Furthermore, we verified that the in vitro assay could be successfully utilized to screen for molecules that can ameliorate hypoxia/ischemia-induced axonal degeneration.


Assuntos
Axônios/patologia , Axônios/fisiologia , Isquemia Encefálica/patologia , Isquemia Encefálica/fisiopatologia , Modelos Animais de Doenças , Substância Branca/patologia , Substância Branca/fisiopatologia , Animais , Hipóxia Celular , Cerebelo/patologia , Cerebelo/fisiopatologia , Lisossomos/fisiologia , Camundongos Endogâmicos C57BL , Bainha de Mielina/patologia , Técnicas de Cultura de Órgãos , Proteólise , Receptores de AMPA/fisiologia
10.
Opt Express ; 28(21): 32002-32009, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33115163

RESUMO

The multipath interference (MPI) noise is one of the most important limiting factors on the performance of the mobile fronthaul network (MFN) based on the radio-over-fiber (RoF) technology. Recently, it has been proposed to suppress this MPI noise by using the Gaussian phase dither. However, it broadens the optical spectrum significantly and, as a result, increases its vulnerability to the chromatic dispersion. To overcome this problem, we propose to suppress the MPI noise by using the RF-chirp dither instead of the Gaussian dither. The results show that, due to the narrow optical spectrum achieved by the RF-chirp dither, we can increase the transmission distance of the RoF-based MFN operating in the 1.5-µm region by three times.

11.
Proc Natl Acad Sci U S A ; 114(25): E4987-E4995, 2017 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-28584116

RESUMO

Maintenance of white matter integrity in health and disease is critical for a variety of neural functions. Ischemic stroke in the white matter frequently results in degeneration of oligodendrocytes (OLs) and myelin. Previously, we found that toll-like receptor 2 (TLR2) expressed in OLs provides cell-autonomous protective effects on ischemic OL death and demyelination in white matter stroke. Here, we identified high-mobility group box-1 (HMGB1) as an endogenous TLR2 ligand that promotes survival of OLs under ischemic stress. HMGB1 rapidly accumulated in the culture medium of OLs exposed to oxygen-glucose deprivation (OGD). This conditioned medium exhibited a protective activity against ischemic OL death that was completely abolished by immunodepletion of HMGB1. Knockdown of HMGB1 or application of glycyrrhizin, a specific HMGB1 inhibitor, aggravated OGD-induced OL death, and recombinant HMGB1 application reduced the extent of OL death in a TLR2-dependent manner. We confirmed that cytosolic translocation of HMGB1 and activation of TLR2-mediated signaling pathways occurred in a focal white matter stroke model induced by endothelin-1 injection. Animals with glycyrrhizin coinjection showed an expansion of the demyelinating lesion in a TLR2-dependent manner, accompanied by aggravation of sensorimotor behavioral deficits. These results indicate that HMGB1/TLR2 activates an autocrine trophic signaling pathways in OLs and myelin to maintain structural and functional integrity of the white matter under ischemic conditions.


Assuntos
Proteína HMGB1/metabolismo , Acidente Vascular Cerebral/metabolismo , Substância Branca/metabolismo , Animais , Isquemia Encefálica/metabolismo , Células Cultivadas , Doenças Desmielinizantes/metabolismo , Endotelina-1/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Bainha de Mielina/metabolismo , Oligodendroglia/metabolismo , Transdução de Sinais/fisiologia , Receptor 2 Toll-Like/metabolismo
12.
Small ; 15(18): e1900235, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30963717

RESUMO

All-solid-state batteries (ASSBs) have lately received enormous attention for electric vehicle applications because of their exceptional stability by engaging all-solidified cell components. However, there are many formidable hurdles such as low ionic conductivity, interface instability, and difficulty in the manufacturing process, for its practical use. Recently, carbon, one of the representative conducting agents, turns out to largely participate in side reactions with the solid electrolyte, which finally leads to the formation of insulating side products at the interface. Although the battery community mentioned that parasitic reactions are presumably attributed to carbon itself or the generation of electronic conducting paths lowering the kinetic barrier for reactions, the underlying origin for such reactions as well as appropriate solutions have not been provided yet. In this study, for the first time, it is verified that the functional group on carbon is an origin for causing negative effects on interfacial stability and a graphitized hollow nanocarbon as a promising solution for improving-electrochemical performance is introduced. This work offers an invaluable lesson that a relatively minor part, such as a conducting agent, in ASSBs sometimes gives more positive impact on improving electrochemical performance than huge efforts for resolving other parts.

13.
Glia ; 66(2): 445-458, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29105838

RESUMO

Defects in repair of damaged brain accumulate injury and contribute to slow-developing neurodegeneration. Here, we report that a deficiency of DJ-1, a Parkinson's disease (PD) gene, delays repair of brain injury due to destabilization of Sox9, a positive regulator of astrogliosis. Stereotaxic injection of ATP into the brain striatum produces similar size of acute injury in wild-type and DJ-1-knockout (KO) mice. However, recovery of the injury is delayed in KO mice, which is confirmed by 9.4T magnetic resonance imaging and tyrosine hydroxylase immunostaining. DJ-1 regulates neurite outgrowth from damaged neurons in a non-cell autonomous manner. In DJ-1 KO brains and astrocytes, Sox9 protein levels are decreased due to enhanced ubiquitination, resulting in defects in astrogliosis and glial cell-derived neurotrophic factor/ brain-derived neurotrophic factor expression in injured brain and astrocytes. These results indicate that DJ-1 deficiency causes defects in astrocyte-mediated repair of brain damage, which may contribute to the development of PD.


Assuntos
Astrócitos/metabolismo , Lesões Encefálicas/metabolismo , Gliose/metabolismo , Proteína Desglicase DJ-1/deficiência , Fatores de Transcrição SOX9/metabolismo , Animais , Astrócitos/patologia , Lesões Encefálicas/genética , Lesões Encefálicas/patologia , Células Cultivadas , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Gliose/genética , Gliose/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Técnicas de Cultura de Órgãos , Doença de Parkinson/genética , Doença de Parkinson/metabolismo , Proteína Desglicase DJ-1/genética , Estabilidade Proteica , Fatores de Transcrição SOX9/genética
14.
Opt Express ; 25(11): 12152-12160, 2017 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-28786573

RESUMO

We propose and demonstrate a simple composite second-order (CSO) cancellation technique based on the digital signal processing (DSP) for the radio-over-fiber (RoF) transmission system implemented by using directly modulated lasers (DMLs). When the RoF transmission system is implemented by using DMLs, its performance could be limited by the CSO distortions caused by the interplay between the DML's chirp and fiber's chromatic dispersion. We present the theoretical analysis of these nonlinear distortions and show that they can be suppressed at the receiver by using a simple DSP. To verify the effectiveness of the proposed technique, we demonstrate the transmission of twenty-four 100-MHz filtered orthogonal frequency-division multiplexing (f-OFDM) signals in 64 quadrature amplitude modulation (QAM) format over 20 km of the standard single-mode fiber (SSMF). The results show that, by using the proposed technique, we can suppress the CSO distortion components by >10 dB and achieve the error-vector magnitude performance better than 6% even after the 20-km long SSMF transmission.

15.
Opt Express ; 25(13): 14282-14289, 2017 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-28789013

RESUMO

There have been substantial efforts to implement high-speed (>10 Gb/s) upstream transmission using reflective semiconductor optical amplifiers (RSOAs) in a coherent wavelength-division-multiplexed (WDM) passive optical network (PON). In such a network, it is necessary to estimate the carrier phase of upstream optical signal to retrieve the phase-modulated information created by RSOA. However, due to the severe waveform distortions caused by the limited modulation bandwidth of RSOA (typically less than 3 GHz), previously reported carrier phase estimation (CPE) algorithms cannot accurately estimate the carrier phase of high-speed quadrature phase-shift keying (QPSK) signal generated from the RSOA seeded by a distributed-feedback (DFB) laser. We propose a novel CPE method capable of tracking the carrier phase rapidly by using a small number of symbols (e.g., 15 symbols) even when the waveforms are severely distorted by the limited modulation bandwidth of RSOA. The proposed CPE method utilizes the linear relationship between the intensity modulation and phase modulation indices inherent in the semiconductor opto-electronic device. By using the proposed method, we demonstrate the transmission of 25.78-Gb/s QPSK signal in a 20-km long loopback fiber link. In this experiment, a commercial DFB laser (linewidth: 3 MHz) is used as the seed light instead of an expensive narrow-linewidth laser. Also shown through the experiment is that the proposed CPE method is highly unsusceptible to variations of parameters required in the proposed method, such as the number of test phases, the accuracy of linewidth enhancement factor, and the accuracy of the normalized amplitude of DC component.

16.
Proc Natl Acad Sci U S A ; 111(2): 599-604, 2014 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-24379365

RESUMO

Sodium ion batteries offer promising opportunities in emerging utility grid applications because of the low cost of raw materials, yet low energy density and limited cycle life remain critical drawbacks in their electrochemical operations. Herein, we report a vanadium-based ortho-diphosphate, Na7V4(P2O7)4PO4, or VODP, that significantly reduces all these drawbacks. Indeed, VODP exhibits single-valued voltage plateaus at 3.88 V vs. Na/Na(+) while retaining substantial capacity (>78%) over 1,000 cycles. Electronic structure calculations reveal that the remarkable single plateau and cycle life originate from an intermediate phase (a very shallow voltage step) that is similar both in the energy level and lattice parameters to those of fully intercalated and deintercalated states. We propose a theoretical scheme in which the reaction barrier that arises from lattice mismatches can be evaluated by using a simple energetic consideration, suggesting that the presence of intermediate phases is beneficial for cell kinetics by buffering the differences in lattice parameters between initial and final phases. We expect these insights into the role of intermediate phases found for VODP hold in general and thus provide a helpful guideline in the further understanding and design of battery materials.


Assuntos
Difosfatos/química , Fontes de Energia Elétrica , Compostos de Vanádio/química , Cristalografia , Eletroquímica , Cinética , Modelos Teóricos , Difração de Raios X
17.
J Neurosci ; 35(48): 15934-47, 2015 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-26631474

RESUMO

CNS neurons in adult mammals do not spontaneously regenerate axons after spinal cord injury. Preconditioning peripheral nerve injury allows the dorsal root ganglia (DRG) sensory axons to regenerate beyond the injury site by promoting expression of regeneration-associated genes. We have previously shown that peripheral nerve injury increases the number of macrophages in the DRGs and that the activated macrophages are critical to the enhancement of intrinsic regeneration capacity. The present study identifies a novel chemokine signal mediated by CCL2 that links regenerating neurons with proregenerative macrophage activation. Neutralization of CCL2 abolished the neurite outgrowth activity of conditioned medium obtained from neuron-macrophage cocultures treated with cAMP. The neuron-macrophage interactions that produced outgrowth-promoting conditioned medium required CCL2 in neurons and CCR2/CCR4 in macrophages. The conditioning effects were abolished in CCL2-deficient mice at 3 and 7 d after sciatic nerve injury, but CCL2 was dispensable for the initial growth response and upregulation of GAP-43 at the 1 d time point. Intraganglionic injection of CCL2 mimicked conditioning injury by mobilizing M2-like macrophages. Finally, overexpression of CCL2 in DRGs promoted sensory axon regeneration in a rat spinal cord injury model without harmful side effects. Our data suggest that CCL2-mediated neuron-macrophage interaction plays a critical role for amplification and maintenance of enhanced regenerative capacity by preconditioning peripheral nerve injury. Manipulation of chemokine signaling mediating neuron-macrophage interactions may represent a novel therapeutic approach to promote axon regeneration after CNS injury.


Assuntos
Quimiocina CCL2/metabolismo , Macrófagos/fisiologia , Regeneração Nervosa/genética , Neurônios/fisiologia , Traumatismos dos Nervos Periféricos/fisiopatologia , Animais , Células Cultivadas , Quimiocina CCL2/genética , Toxina da Cólera/metabolismo , Técnicas de Cocultura , Dependovirus/genética , Modelos Animais de Doenças , Feminino , Gânglios Espinais/citologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Regeneração Nervosa/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Neuritos/fisiologia , Neurônios/citologia , Medição da Dor , Limiar da Dor/fisiologia , Ratos , Ratos Sprague-Dawley , Receptores CCR2/genética , Receptores CCR2/metabolismo
18.
J Neurosci ; 34(38): 12788-800, 2014 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-25232115

RESUMO

Combining cell transplantation with activity-based rehabilitation is a promising therapeutic approach for spinal cord repair. The present study was designed to investigate potential interactions between the transplantation (TP) of neural stem cells (NSCs) obtained at embryonic day 14 and treadmill training (TMT) in promoting locomotor recovery and structural repair in rat contusive injury model. Combination of TMT with NSC TP at 1 week after injury synergistically improved locomotor function. We report here that combining TMT increased the survival of grafted NSCs by >3-fold and >5-fold at 3 and 9 weeks after injury, respectively. The number of surviving NSCs was significantly correlated with the extent of locomotor recovery. NSCs grafted into the injured spinal cord were under cellular stresses induced by reactive nitrogen or oxygen species, which were markedly attenuated by TMT. TMT increased the concentration of insulin-like growth factor-1 (IGF-1) in the CSF. Intrathecal infusion of neutralizing IGF-1 antibodies, but not antibodies against either BDNF or Neurotrophin-3 (NT-3), abolished the enhanced survival of NSC grafts by TMT. The combination of TP and TMT also resulted in tissue sparing, increased myelination, and restoration of serotonergic fiber innervation to the lumbar spinal cord to a larger extent than that induced by either TP or TMT alone. Therefore, we have discovered unanticipated beneficial effects of TMT in modulating the survival of grafted NSCs via IGF-1. Our study identifies a novel neurobiological basis for complementing NSC-based spinal cord repair with activity-based neurorehabilitative approaches.


Assuntos
Fator de Crescimento Insulin-Like I/fisiologia , Atividade Motora/fisiologia , Células-Tronco Neurais/fisiologia , Células-Tronco Neurais/transplante , Transdução de Sinais , Traumatismos da Medula Espinal/reabilitação , Traumatismos da Medula Espinal/terapia , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Fator Neurotrófico Derivado do Encéfalo/imunologia , Sobrevivência Celular/imunologia , Sobrevivência Celular/fisiologia , Terapia Combinada/métodos , Feminino , Injeções Espinhais , Fator de Crescimento Insulin-Like I/imunologia , Fator de Crescimento Insulin-Like I/metabolismo , Região Lombossacral/inervação , Bainha de Mielina/metabolismo , Neurotrofina 3/imunologia , Ratos , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Recuperação de Função Fisiológica/fisiologia , Neurônios Serotoninérgicos/fisiologia , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/fisiopatologia , Regeneração da Medula Espinal/imunologia , Regeneração da Medula Espinal/fisiologia
19.
J Am Chem Soc ; 137(22): 7210-6, 2015 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-26000786

RESUMO

Various dry sorbents have been lately introduced as promising media to capture carbon dioxide (CO2). However, it is still desirable to further improve their performance in diverse aspects, and high temperature selectivity of CO2 over other gases is clearly one of them. Here, we report a co-assembly approach to turn nonporous melamine resin to a highly ordered mesoporous polymeric network (space group: Im3̅m) containing high nitrogen content (∼18 at%). This mesoporous network shows anomalously increasing CO2/N2 selectivity with temperature rise, with the selectivity at 323 K reaching 117 (Henry method). This selectivity behavior is attributed to a combined effect of the high nitrogen content allowing for high binding affinity with CO2 and well-defined mesopores (2.5-2.9 nm) accelerating release of N2 with temperature rise. The given orthogonal approach suggests a new direction in designing dry sorbents with excellent selectivities at high temperatures.

20.
Int J Mol Sci ; 16(9): 21021-34, 2015 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-26404252

RESUMO

Atopic dermatitis (AD) is a chronic and inflammatory skin disease that can place a significant burden on quality of life for patients. AD most frequently appears under the age of six and although its prevalence is increasing worldwide, therapeutic treatment options are limited. Chlorella vulgaris (CV) is a species of the freshwater green algae genus chlorella, and has been reported to modulate allergy-inducible factors when ingested. Here, we examined the effect of CV supplementation on AD-like symptoms in NC/Nga mice. CV was orally administrated for six weeks while AD-like symptoms were induced via topical application of Dermatophagoides farinae extract (DFE). CV treatment reduced dermatitis scores, epidermal thickness, and skin hydration. Histological analysis also revealed that CV treatment reduced DFE-induced eosinophil and mast cell infiltration into the skin, while analysis of serum chemokine levels indicated that CV treatment downregulated thymus- and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) levels. In addition, CV treatment downregulated mRNA expression levels of IL-4 and IFN-γ. Taken together, these results suggest that CV extract may have potential as a nutraceutical ingredient for the prevention of AD.


Assuntos
Chlorella vulgaris/química , Dermatite Atópica/tratamento farmacológico , Dermatophagoides farinae/patogenicidade , Suplementos Nutricionais/microbiologia , Imunossupressores/administração & dosagem , Animais , Quimiocinas/sangue , Dermatite Atópica/imunologia , Dermatite Atópica/parasitologia , Modelos Animais de Doenças , Esquema de Medicação , Eosinófilos/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Mastócitos/efeitos dos fármacos , Camundongos
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