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1.
J Neurosci ; 43(6): 885-901, 2023 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-36535770

RESUMO

Memory formation and maintenance is a dynamic process involving the modulation of the actin cytoskeleton at synapses. Understanding the signaling pathways that contribute to actin modulation is important for our understanding of synapse formation and function, as well as learning and memory. Here, we focused on the importance of the actin regulator, noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1), in hippocampal dependent behaviors and development. We report that male mice lacking NCK1 have impairments in both short-term and working memory, as well as spatial learning. Additionally, we report sex differences in memory impairment showing that female mice deficient in NCK1 fail at reversal learning in a spatial learning task. We find that NCK1 is expressed in postmitotic neurons but is dispensable for neuronal proliferation and migration in the developing hippocampus. Morphologically, NCK1 is not necessary for overall neuronal dendrite development. However, neurons lacking NCK1 have lower dendritic spine and synapse densities in vitro and in vivo EM analysis reveal increased postsynaptic density (PSD) thickness in the hippocampal CA1 region of NCK1-deficient mice. Mechanistically, we find the turnover of actin-filaments in dendritic spines is accelerated in neurons that lack NCK1. Together, these findings suggest that NCK1 contributes to hippocampal-dependent memory by stabilizing actin dynamics and dendritic spine formation.SIGNIFICANCE STATEMENT Understanding the molecular signaling pathways that contribute to memory formation, maintenance, and elimination will lead to a better understanding of the genetic influences on cognition and cognitive disorders and will direct future therapeutics. Here, we report that the noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) adaptor protein modulates actin-filament turnover in hippocampal dendritic spines. Mice lacking NCK1 show sex-dependent deficits in hippocampal memory formation tasks, have altered postsynaptic densities, and reduced synaptic density. Together, our work implicates NCK1 in the regulation of actin cytoskeleton dynamics and normal synapse development which is essential for memory formation.


Assuntos
Actinas , Espinhas Dendríticas , Animais , Feminino , Masculino , Camundongos , Actinas/metabolismo , Espinhas Dendríticas/metabolismo , Hipocampo/metabolismo , Neurônios/fisiologia , Proteínas Tirosina Quinases/metabolismo , Sinapses/fisiologia , Memória
2.
BMC Neurol ; 19(1): 345, 2019 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-31884946

RESUMO

BACKGROUND: Hyperprolinemia type 2 (HPII) is a rare autosomal recessive disorder of the proline metabolism, that affects the ALDH4A1 gene. So far only four different pathogenic mutations are known. The manifestation is mostly in neonatal age, in early infancy or early childhood. CASE PRESENTATION: The 64-years female patient had a long history of abdominal pain, and episode of an acute neuritis. Ten years later she was admitted into the neurological intensive-care-unit with acute abdominal pain, multiple generalized epileptic seizures, a vertical gaze palsy accompanied by extensive lactic acidosis in serum 26.0 mmol/l (reference: 0.55-2.2 mmol/l) and CSF 12.01 mmol/l (reference: 1.12-2.47 mmol/l). Due to repeated epileptic seizures and secondary complications a long-term sedation with a ventilation therapy over 20 days was administered. A diagnostic work-up revealed up to 400-times increased prolin-level in urine CSF and blood. Furthermore, a low vitamin-B6 serum value was found, consistent with a HPII causing secondary pyridoxine deficiency and seizures. The ALDH4A1 gene sequencing confirmed two previously unknown compound heterozygous variants (ALDH4A1 gene (NM_003748.3) Intron 1: c.62 + 1G > A - heterozygous and ALDH4A1 gene (NM_003748.3) Exon 5 c.349G > C, p.(Asp117His) - heterozygous). Under high-dose vitamin-B6 therapy no further seizures occurred. CONCLUSION: We describe two novel ALDH4A1-variants in an adult patient with hyperprolinemia type II causing secondary pyridoxine deficiency and seizures. Severe and potentially life-threatening course of this treatable disease emphasizes the importance of diagnostic vigilance and thorough laboratory work-up including gene analysis even in cases with atypical late manifestation.


Assuntos
1-Pirrolina-5-Carboxilato Desidrogenase/deficiência , Erros Inatos do Metabolismo dos Aminoácidos/genética , 1-Pirrolina-5-Carboxilato Desidrogenase/genética , Acidose Láctica/etiologia , Adulto , Erros Inatos do Metabolismo dos Aminoácidos/complicações , Feminino , Humanos , Mutação , Estado Epiléptico/etiologia
3.
Clin Chem Lab Med ; 57(9): 1308-1318, 2019 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-30721141

RESUMO

Background Procalcitonin (PCT)-guided antibiotic stewardship (ABS) has been shown to reduce antibiotics (ABxs), with lower side-effects and an improvement in clinical outcomes. The aim of this experts workshop was to derive a PCT algorithm ABS for easier implementation into clinical routine across different clinical settings. Methods Clinical evidence and practical experience with PCT-guided ABS was analyzed and discussed, with a focus on optimal PCT use in the clinical context and increased adherence to PCT protocols. Using a Delphi process, the experts group reached consensus on different PCT algorithms based on clinical severity of the patient and probability of bacterial infection. Results The group agreed that there is strong evidence that PCT-guided ABS supports individual decisions on initiation and duration of ABx treatment in patients with acute respiratory infections and sepsis from any source, thereby reducing overall ABx exposure and associated side effects, and improving clinical outcomes. To simplify practical application, the expert group refined the established PCT algorithms by incorporating severity of illness and probability of bacterial infection and reducing the fixed cut-offs to only one for mild to moderate and one for severe disease (0.25 µg/L and 0.5 µg/L, respectively). Further, guidance on interpretation of PCT results to initiate, withhold or discontinue ABx treatment was included. Conclusions A combination of clinical patient assessment with PCT levels in well-defined ABS algorithms, in context with continuous education and regular feedback to all ABS stakeholders, has the potential to improve the diagnostic and therapeutic management of patients suspected of bacterial infection, thereby improving ABS effectiveness.


Assuntos
Gestão de Antimicrobianos/métodos , Pró-Calcitonina/metabolismo , Adulto , Algoritmos , Antibacterianos/uso terapêutico , Infecções Bacterianas/diagnóstico , Biomarcadores/sangue , Calcitonina/uso terapêutico , Consenso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pró-Calcitonina/fisiologia , Sepse/diagnóstico
4.
Biomed Eng Online ; 12: 7, 2013 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-23356939

RESUMO

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) can replace the lungs' gas exchange capacity in refractory lung failure. However, its limited hemocompatibility, the activation of the coagulation and complement system as well as plasma leakage and protein deposition hamper mid- to long-term use and have constrained the development of an implantable lung assist device. In a tissue engineering approach, lining the blood contact surfaces of the ECMO device with endothelial cells might overcome these limitations. As a first step towards this aim, we hypothesized that coating the oxygenator's gas exchange membrane with proteins might positively influence the attachment and proliferation of arterial endothelial cells. METHODS: Sheets of polypropylene (PP), polyoxymethylpentene (TPX) and polydimethylsiloxane (PDMS), typical material used for oxygenator gas exchange membranes, were coated with collagen, fibrinogen, gelatin or fibronectin. Tissue culture treated well plates served as controls. Endothelial cell attachment and proliferation were analyzed for a period of 4 days by microscopic examination and computer assisted cell counting. RESULTS: Endothelial cell seeding efficiency is within range of tissue culture treated controls for fibronectin treated surfaces only. Uncoated membranes as well as all other coatings lead to lower cell attachment. A confluent endothelial cell layer develops on fibronectin coated PDMS and the control surface only. CONCLUSIONS: Fibronectin increases endothelial cells' seeding efficiency on different oxygenator membrane material. PDMS coated with fibronectin shows sustained cell attachment for a period of four days in static culture conditions.


Assuntos
Células Endoteliais/citologia , Fibronectinas/química , Oxigenadores de Membrana , Animais , Materiais Biocompatíveis , Adesão Celular , Colágeno/química , Dimetilpolisiloxanos/química , Endotélio Vascular/citologia , Oxigenação por Membrana Extracorpórea/métodos , Fibrinogênio/química , Gelatina/química , Polipropilenos/química , Ovinos , Técnicas de Cultura de Tecidos , Engenharia Tecidual/métodos
5.
Proc Natl Acad Sci U S A ; 107(19): 8836-41, 2010 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-20421490

RESUMO

The likelihood with which an action potential elicits neurotransmitter release, the release probability (p(r)), is an important component of synaptic strength. Regulatory mechanisms controlling several steps of synaptic vesicle (SV) exocytosis may affect p(r), yet their relative importance in determining p(r) and eliciting temporal changes in neurotransmitter release at individual synapses is largely unknown. We have investigated whether the size of the active zone cytomatrix is a major determinant of p(r) and whether changes in its size lead to corresponding alterations in neurotransmitter release. We have used a fluorescent sensor of SV exocytosis, synaptophysin-pHluorin, to measure p(r) at individual synapses with high accuracy and employed a fluorescently labeled cytomatrix protein, Bassoon, to quantify the amount of active zone cytomatrix present at these synapses. We find that, for synapses made by a visually identified presynaptic neuron, p(r) is indeed strongly correlated with the amount of active zone cytomatrix present at the presynaptic specialization. Intriguingly, active zone cytomatrices are frequently subject to synapse-specific changes in size on a time scale of minutes. These spontaneous alterations in active zone size are associated with corresponding changes in neurotransmitter release. Our results suggest that the size of the active zone cytomatrix has a large influence on the reliability of synaptic transmission. Furthermore, they implicate mechanisms leading to rapid structural alterations at active zones in synapse-specific forms of plasticity.


Assuntos
Neurotransmissores/metabolismo , Vesículas Sinápticas/química , Vesículas Sinápticas/metabolismo , Animais , Técnicas Biossensoriais , Exocitose , Proteínas de Fluorescência Verde/metabolismo , Hipocampo/metabolismo , Plasticidade Neuronal , Probabilidade , Ratos , Sinaptofisina/metabolismo , Fatores de Tempo
6.
Sensors (Basel) ; 13(1): 898-917, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23344383

RESUMO

Body sensor networks (BSN) are an important research topic due to various advantages over conventional measurement equipment. One main advantage is the feasibility to deploy a BSN system for 24/7 health monitoring applications. The requirements for such an application are miniaturization of the network nodes and the use of wireless data transmission technologies to ensure wearability and ease of use. Therefore, the reliability of such a system depends on the quality of the wireless data transmission. At present, most BSNs use ZigBee or other IEEE 802.15.4 based transmission technologies. Here, we evaluated the performance of a wireless transmission system of a novel BSN for biomedical applications in the 433MHz ISM band, called Integrated Posture and Activity NEtwork by Medit Aachen (IPANEMA) BSN. The 433MHz ISM band is used mostly by implanted sensors and thus allows easy integration of such into the BSN. Multiple measurement scenarios have been assessed, including varying antenna orientations, transmission distances and the number of network participants. The mean packet loss rate (PLR) was 0.63% for a single slave, which is comparable to IEEE 802.15.4 BSNs in the proximity of Bluetooth or WiFi networks. Secondly, an enhanced version is evaluated during on-body measurements with five slaves. The mean PLR results show a comparable good performance for measurements on a treadmill (2.5%), an outdoor track (3.4%) and in a climate chamber (1.5%).


Assuntos
Tecnologia Biomédica/instrumentação , Tecnologia Biomédica/métodos , Monitorização Ambulatorial/instrumentação , Redes de Comunicação de Computadores/instrumentação , Humanos , Processamento de Sinais Assistido por Computador , Análise Espectral , Fatores de Tempo
7.
J Neurosci ; 30(13): 4796-805, 2010 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-20357130

RESUMO

The formation and function of the neuronal synapse is dependent on the asymmetric distribution of proteins both presynaptically and postsynaptically. Recently, proteins important in establishing cellular polarity have been implicated in the synapse. We therefore performed a proteomic screen with known polarity proteins and identified novel complexes involved in synaptic function. Specifically, we show that the tumor suppressor protein, Scribble, associates with neuronal nitric oxide synthase (nNOS) adaptor protein (NOS1AP) [also known as C-terminal PDZ ligand of nNOS (CAPON)] and is found both presynaptically and postsynaptically. The Scribble-NOS1AP association is direct and is mediated through the phosphotyrosine-binding (PTB) domain of NOS1AP and the fourth PDZ domain of Scribble. Further, we show that Scribble bridges NOS1AP to a beta-Pix [beta-p21-activated kinase (PAK)-interacting exchange factor]/Git1 (G-protein-coupled receptor kinase-interacting protein)/PAK complex. The overexpression of NOS1AP leads to an increase in dendritic protrusions, in a fashion that depends on the NOS1AP PTB domain. Consistent with these observations, both full-length NOS1AP and the NOS1AP PTB domain influence Rac activity. Together these data suggest that NOS1AP plays an important role in the mammalian synapse.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Espinhas Dendríticas/fisiologia , Proteínas Supressoras de Tumor/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Dados de Sequência Molecular , Complexos Multiproteicos , Fosfotirosina/metabolismo , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , Ratos , Fatores de Troca de Nucleotídeo Guanina Rho , Quinases Ativadas por p21/metabolismo , Proteínas rac de Ligação ao GTP/metabolismo
8.
Hum Mutat ; 32(4): 424-35, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21309039

RESUMO

The effects of missense changes and small in-frame deletions and insertions on protein function are not easy to predict, and the identification of such variants in individuals at risk of a genetic disease can complicate genetic counselling. One option is to perform functional tests to assess whether the variants affect protein function. We have used this strategy to characterize variants identified in the TSC1 and TSC2 genes in individuals with, or suspected of having, Tuberous Sclerosis Complex (TSC). Here we present an overview of our functional studies on 45 TSC1 and 107 TSC2 variants. Using a standardized protocol we classified 16 TSC1 variants and 70 TSC2 variants as pathogenic. In addition we identified eight putative splice site mutations (five TSC1 and three TSC2). The remaining 24 TSC1 and 34 TSC2 variants were classified as probably neutral.


Assuntos
Variação Genética , Esclerose Tuberosa/genética , Proteínas Supressoras de Tumor/genética , Células Cultivadas , Humanos , Modelos Genéticos , Esclerose Tuberosa/metabolismo , Proteína 1 do Complexo Esclerose Tuberosa , Proteína 2 do Complexo Esclerose Tuberosa
9.
Urol Int ; 86(4): 393-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21335950

RESUMO

OBJECTIVES: Endorectal coil MRI (endoMRI) of the prostate is useful to evaluate tumor localization. There is little evidence on patient characteristics affecting its diagnostic performance. We evaluate the influence of clinical and histological parameters on the accuracy of endoMRI. METHODS: Sixty-nine patients with prostate cancer were included. After virtually dividing the prostate into pixels of 1 cm2, results of endoMRI were compared with those from prostatectomy specimens' whole-mount sections. Univariate and multivariate analyses were performed to calculate the impact of clinical and histological parameters on the number of appropriately described pixels. RESULTS: In 9, no tumor could be demonstrated by endoMRI. 48.3% of patients were staged correctly, 23.3% were over- and 28.3% understaged. Mean rates of correctly labeled pixels were 0.44 (± 0.04 SEM) for tumor and 0.90 (± 0.01) for benign segments. In univariate analysis, the rate of correctly labeled tumor segments showed significant positive correlations with Gleason score ≥7 and negative correlations with prostate weight and multifocality. The rate of correctly labeled benign segments showed significant negative correlation with tumor weight. All factors were independent variables in multivariate analysis. CONCLUSIONS: The reliability of endoMRI depends on clinical parameters. Higher Gleason scores, unifocal tumors and smaller prostate volumes ameliorate endoMRI performance.


Assuntos
Imageamento por Ressonância Magnética/métodos , Neoplasias da Próstata/patologia , Idoso , Humanos , Masculino , Oncologia/métodos , Pessoa de Meia-Idade , Estadiamento de Neoplasias/métodos , Tamanho do Órgão , Próstata/patologia , Antígeno Prostático Específico/biossíntese , Prostatectomia/métodos , Neoplasias da Próstata/diagnóstico
10.
J Thorac Oncol ; 16(4): 572-582, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33309988

RESUMO

INTRODUCTION: Robust data on the outcome of MET-aberrant NSCLC with nontargeted therapies are limited, especially in consideration of the heterogeneity of MET-amplified tumors (METamp). METHODS: A total of 337 tumor specimens of patients with MET-altered Union for International Cancer Control stage IIIB/IV NSCLC were analyzed using next-generation sequencing, fluorescence in situ hybridization, and immunohistochemistry. The evaluation focused on the type of MET aberration, co-occurring mutations, programmed death-ligand 1 expression, and overall survival (OS). RESULTS: METamp tumors (n = 278) had a high frequency of co-occurring mutations (>80% for all amplification levels), whereas 57.6% of the 59 patients with MET gene and exon 14 (METex14) tumors had no additional mutations. In the METamp tumors, with increasing gene copy number (GCN), the frequency of inactivating TP53 mutations increased (GCN < 4: 58.2%; GCN ≥ 10: 76.5%), whereas the frequency of KRAS mutations decreased (GCN < 4: 43.2%; GCN ≥ 10: 11.8%). A total of 10.1% of all the METamp tumors with a GCN ≥ 10 had a significant worse OS (4.0 mo; 95% CI: 1.9-6.0) compared with the tumors with GCN < 10 (12.0 mo; 95% confidence interval [CI]: 9.4-14.6). In the METamp NSCLC, OS with immune checkpoint inhibitor (ICI) therapy was significantly better compared with chemotherapy with 19.0 months (95% CI: 15.8-22.2) versus 8.0 months (95% CI: 5.8-10.2, p < 0.0001). No significant difference in median OS was found between ICI therapy and chemotherapy in the patients with METex14 (p = 0.147). CONCLUSIONS: METex14, METamp GCN ≥ 10, and METamp GCN < 10 represent the subgroups of MET-dysregulated NSCLC with distinct molecular and clinical features. The patients with METex14 do not seem to benefit from immunotherapy in contrast to the patients with METamp, which is of particular relevance for the prognostically poor METamp GCN ≥ 10 subgroup.


Assuntos
Neoplasias Pulmonares , Heterogeneidade Genética , Humanos , Imunoterapia , Hibridização in Situ Fluorescente , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Mutação , Proteínas Proto-Oncogênicas c-met/genética
11.
J Neurochem ; 114(1): 311-22, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20456004

RESUMO

Imbalances in brain cholesterol homeostasis have been observed in several neurodegenerative diseases. In Niemann-Pick Type C (NPC) disease, mutations in NPC1 or NPC2 lead to endosomal cholesterol accumulation, neuronal dysfunction and death. Cholesterol in synaptic plasma membranes influences membrane fluidity, curvature, and protein function, and its depletion may adversely affect synaptic vesicle cycling. We have investigated pre-synaptic function in primary hippocampal neurons with altered cholesterol distribution because of NPC1 deficiency or cyclodextrin treatment. In NPC1-deficient neurons grown in serum-free medium, plasma membrane cholesterol was reduced and total synaptic vesicle release during prolonged stimulation was attenuated. In NPC1-deficient neurons cultured in the presence of high-density lipoproteins, plasma membrane cholesterol markedly increased, but the defects in synaptic vesicle release in NPC1-deficient neurons were exacerbated. Treatment with 1 mM methyl-beta-cyclodextrin acutely depleted plasma membrane cholesterol in wild-type neurons to levels below those in NPC1 deficiency, but did not alter synaptic vesicle exo- or endocytosis. Defects only became apparent when higher methyl-beta-cyclodextrin concentrations were used. Our data indicate that synaptic vesicle release can tolerate some degree of plasma membrane cholesterol depletion and suggest that the pre-synaptic defects in NPC1-deficient neurons are not solely caused by a reduction of plasma membrane cholesterol.


Assuntos
Membrana Celular/metabolismo , Colesterol/metabolismo , Hipocampo/metabolismo , Neurônios/metabolismo , Proteínas/genética , Animais , Ciclodextrinas/farmacologia , Endocitose , Endossomos/metabolismo , Exocitose , Corantes Fluorescentes , Genes Reporter , Peptídeos e Proteínas de Sinalização Intracelular , Lipoproteínas HDL/farmacologia , Camundongos , Camundongos Knockout , Proteína C1 de Niemann-Pick , Proteínas/fisiologia , Compostos de Piridínio , Compostos de Amônio Quaternário , Vesículas Sinápticas/metabolismo
12.
Dermatol Online J ; 15(10): 4, 2009 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-19951622

RESUMO

Basal cell carcinoma (BCC), the most common cutaneous malignant tumor, may display neuroendocrine differentiation in very rare instances. We here describe a case of a BCC with neuroendocrine differentiation that arose in a scar resulting from a trauma 75 years earlier. Neuroendocrine differentiation was proven by immunohistochemistry and electron microscopy. The simultaneous occurrence of BCC development in a scar and neuroendocrine differentiation is quite rare.


Assuntos
Carcinoma Basocelular/complicações , Cicatriz/complicações , Neoplasias Cutâneas/complicações , Idoso , Carcinoma Basocelular/patologia , Feminino , Humanos , Neoplasias Cutâneas/patologia
13.
Front Cell Neurosci ; 13: 291, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31316356

RESUMO

Neuronal activity is thought to drive the remodeling of circuits in the mammalian cerebral cortex. However, its precise function in the underlying formation and elimination of glutamatergic synapses has remained controversial. To clarify the role of activity in synapse turnover, we have assessed the effects of inhibition of glutamate release from a sparse subset of cultured hippocampal neurons on synapse turnover. Sustained chemogenetic attenuation of release through presynaptic expression of a designer receptor exclusively activated by designer drugs (DREADD) had no effect on the formation or elimination of glutamatergic synapses. Sparse expression of tetanus neurotoxin light chain (TeNT-LC), a synaptobrevin-cleaving protease that completely abolishes neurotransmitter release, likewise did not lead to changes in the rate of synapse elimination, although it reduced the rate of synapse formation. The stability of active and silenced synapses correlated with measures of synapse size. While not excluding a modulatory role in synapse elimination, our findings show that synaptic activity is neither required for the removal nor the maintenance of glutamatergic synapses between hippocampal neurons. Our results also demonstrate that the stability of glutamatergic synapses scales with their size irrespective of their activity.

14.
Neuron ; 40(5): 945-57, 2003 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-14659093

RESUMO

Whether contact of an axon with a dendrite is a necessary inductive signal for the assembly of functional presynaptic machinery is controversial. Combining FM1-43 imaging with retrospective immunocytochemistry, we observe many functional synaptic vesicle (SV) release sites lacking postsynaptic specializations in cultured hippocampal neurons. These "orphan" release sites share the same exocytic machinery and mechanisms of endocytic recycling as mature synaptic sites. Moreover, quantitative analysis of FM1-43 destaining at these orphan release sites reveals similar kinetics with slightly lower release probabilities. Time-lapse imaging of FM1-43 reveals that orphans are generated by complete or partial mobilization of synaptic release sites that retain their functionality in transit. Orphan clusters fuse with existing synaptic release sites or form novel release sites onto dendrites. Mobilization and stabilization of orphan boutons to new sites of dendritic contact may represent a necessary presynaptic counterpart to postsynaptic changes observed during development and plasticity in the CNS.


Assuntos
Axônios/metabolismo , Comunicação Celular/fisiologia , Dendritos/metabolismo , Terminações Pré-Sinápticas/metabolismo , Animais , Separação Celular , Células Cultivadas , Hipocampo/metabolismo , Ratos , Ratos Sprague-Dawley
15.
J Cell Biol ; 217(2): 715-730, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29317530

RESUMO

The actin cytoskeleton is essential for the structural changes in dendritic spines that lead to the formation of new synapses. Although the molecular mechanisms underlying spine formation are well characterized, the events that drive spine maturation during development are largely unknown. In this study, we demonstrate that Angiomotin (AMOT-130) is necessary for spine stabilization. AMOT-130 is enriched in mature dendritic spines and functions to stabilize the actin cytoskeleton by coupling F-actin to postsynaptic protein scaffolds. These functions of AMOT are transiently restricted during postnatal development by phosphorylation imposed by the kinase Lats1. Our study proposes that AMOT-130 is essential for normal spine morphogenesis and identifies Lats1 as an upstream regulator in this process. Moreover, our findings may link AMOT-130 loss and the related spine defects to neurological disorders.


Assuntos
Espinhas Dendríticas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Angiomotinas , Animais , Células Cultivadas , Ratos , Ratos Sprague-Dawley
16.
Sci Rep ; 7: 42920, 2017 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-28220838

RESUMO

Neurexins are a diverse family of cell adhesion molecules that localize to presynaptic specializations of CNS neurons. Heterologous expression of neurexins in non-neuronal cells leads to the recruitment of postsynaptic proteins in contacting dendrites of co-cultured neurons, implicating neurexins in synapse formation. However, isoform-specific knockouts of either all α- or all ß-neurexins show defects in synaptic transmission but an unaltered density of glutamatergic synapses, a finding that argues against an essential function of neurexins in synaptogenesis. To address the role of neurexin in synapse formation and function, we disrupted the function of all α- and ß-neurexins in cultured hippocampal neurons by shRNA knockdown or by overexpressing a neurexin mutant that is unable to bind to postsynaptic neurexin ligands. We show that neurexin perturbation results in an attenuation of neurotransmitter release that is in large part due to a reduction in the number of readily releasable synaptic vesicles. We also find that neurexin perturbation fails to alter the ability of neurons to form synapses, but rather leads to more frequent synapse elimination. These experiments suggest that neurexins are dispensable for the formation of initial synaptic contacts, but play an essential role in the stabilization and functional maturation of synapses.


Assuntos
Glicoproteínas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuropeptídeos/metabolismo , Sinapses/metabolismo , Animais , Células COS , Células Cultivadas , Chlorocebus aethiops , Técnicas de Cocultura , Glicoproteínas/antagonistas & inibidores , Glicoproteínas/genética , Hipocampo/citologia , Hipocampo/metabolismo , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/genética , Moléculas de Adesão de Célula Nervosa/metabolismo , Neuropeptídeos/antagonistas & inibidores , Neuropeptídeos/genética , Neurotransmissores/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Vesículas Sinápticas/metabolismo
17.
J Neurosci Methods ; 152(1-2): 32-9, 2006 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-16198002

RESUMO

The use of fluorescent probes such as FM 1-43 or synapto-pHluorin to study the dynamic aspects of synaptic function has dramatically increased in recent years. The analysis of such experiments is both labor intensive and subject to potentially significant experimenter bias. For our analysis of fluorescently labeled synapses in cultured hippocampal neurons, we have developed an automated approach to punctum identification and classification. This automatic selection and processing of fluorescently labeled synaptic puncta not only reduces the chance of subjective bias and improves the quality and reproducibility of the analyses, but also greatly increases the number of release sites that can be rapidly analyzed from a given experiment, increasing the signal-to-noise ratio of the data. An important innovation to the automation of analysis is our method for objectively selecting puncta for analysis, particularly important for studying and comparing dynamic functional properties of a large population of individual synapses. The fluorescence change for each individual punctum is automatically scored according to several criteria, allowing objective assessment of the quality of each site. An entirely automated and thus unbiased analysis of fluorescence in the study of synaptic function is critical to providing a comprehensive understanding of the cellular and molecular underpinnings of neurotransmission and plasticity.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Sinapses/fisiologia , Animais , Células Cultivadas , Interpretação Estatística de Dados , Corantes Fluorescentes , Hipocampo/citologia , Hipocampo/metabolismo , Camundongos , Microscopia de Fluorescência , Plasticidade Neuronal/fisiologia , Neurônios/metabolismo , Software , Transmissão Sináptica/fisiologia
18.
J Neurosci ; 23(31): 10093-9, 2003 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-14602824

RESUMO

Regulation of intracellular calcium influences neuronal excitability, synaptic plasticity, gene expression, and neurotoxicity. In this study, we investigated the role of calcium in mechanisms underlying nicotine-mediated neuroprotection from glutamate excitotoxicity. Neuroprotection by nicotine in primary cortical cultures was not seen in knock-out mice lacking the beta2 subunit of the nicotinic acetylcholine receptor (nAChR). Neuroprotection was partially blocked in wild-type cultures by alpha-bungarotoxin, an antagonist of the alpha7 nAChR subtype, suggesting a potential cooperative role for these subtypes. Pretreatment with nicotine decreased glutamate-mediated calcium influx in primary cortical cultures by 41%, an effect that was absent in cultures from knock-out mice lacking the beta2 subunit of the nAChR. This effect was dependent on calcium entry through L-type channels during nicotine pretreatment in wild-type cultures. The ability of nicotine to decrease glutamate-mediated calcium influx was occluded by cotreatment with nifedipine during glutamate application, suggesting that nicotine pretreatment decreased subsequent activity of L-type calcium channels. Treatment with the calcineurin antagonists FK506 and cyclosporine during pretreatment eliminated both nicotine-mediated neuroprotection and the effects of nicotine on L-type channels. We conclude that neuroprotective effects of nicotine in cortical neurons involve both beta2- and alpha7-containing nAChRs, activation of calcineurin, and decreased intracellular calcium via L-type channels.


Assuntos
Calcineurina/metabolismo , Canais de Cálcio Tipo L/efeitos dos fármacos , Córtex Cerebral/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Nicotina/farmacologia , Animais , Bungarotoxinas/farmacologia , Inibidores de Calcineurina , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio Tipo L/metabolismo , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/metabolismo , Ácido Glutâmico/toxicidade , Camundongos , Camundongos Knockout , Neurônios/metabolismo , Neurotoxinas/toxicidade , Nifedipino/farmacologia , Receptores Nicotínicos/deficiência , Receptores Nicotínicos/efeitos dos fármacos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Tacrolimo/farmacologia , Receptor Nicotínico de Acetilcolina alfa7
19.
Acta Orthop Belg ; 70(2): 182-8, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15165024

RESUMO

Primary synovial chondromatosis (PSC) is a rare, usually monoarticular disorder of synovial joints. PSC is characterised by the formation of osteocartilaginous nodules in the synovial connective tissue. We report the case of a 32-year-old male with PSC of the left hip. At clinical examination abduction of the left hip was limited and rotation was painful. Ultrasound examination of the hip revealed joint effusion and multiple hyperechogenic foci due to distal acoustic shadowing. Plain radiographs showed a slight soft tissue swelling around the femoral neck and multiple round or ovoid calcifications of a uniform size. MRI revealed a large joint effusion with multiple small filling defects. Open total synovectomy was performed after dislocation of the femoral head. The diagnosis of PSC was confirmed by histological examination of the excised material. The majority of cells failed to exhibit any staining for cerb B-2 and ki-67. None of the sections showed more than 5% labelling for DNA-fragmentation proven by terminal deoxytransferase-mediated dUTD nick-end labeling (TUNEL), and all were completely non-reactive for p53 as well. In conclusion, immunohistochemical analysis suggests that in this case PSC originated from metaplasia and not from a proliferative process. After two years, the patient was free of symptoms and radiological control did not show evidence of recurrence or femoral head necrosis. Physical findings, diagnosis, histological features and management of PSC are discussed.


Assuntos
Condromatose Sinovial/diagnóstico , Condromatose Sinovial/cirurgia , Articulação do Quadril , Procedimentos Ortopédicos/métodos , Membrana Sinovial/patologia , Adulto , Biópsia por Agulha , Seguimentos , Humanos , Imuno-Histoquímica , Imageamento por Ressonância Magnética/métodos , Masculino , Doenças Raras , Medição de Risco , Índice de Gravidade de Doença , Sinovectomia , Resultado do Tratamento , Ultrassonografia Doppler
20.
J Clin Oncol ; 28(16): 2712-8, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20439646

RESUMO

PURPOSE: Invasion and migration are key processes of glioblastoma and are tightly linked to tumor recurrence. Integrin inhibition using cilengitide has shown synergy with chemotherapy and radiotherapy in vitro and promising activity in recurrent glioblastoma. This multicenter, phase I/IIa study investigated the efficacy and safety of cilengitide in combination with standard chemoradiotherapy in newly diagnosed glioblastoma. PATIENTS AND METHODS: Patients (age > or = 18 to < or = 70 years) were treated with cilengitide (500 mg) administered twice weekly intravenously in addition to standard radiotherapy with concomitant and adjuvant temozolomide. Treatment was continued until disease progression or for up to 35 weeks. The primary end point was progression-free survival (PFS) at 6 months. RESULTS: Fifty-two patients (median age, 57 years; 62% male) were included. Six- and 12-month PFS rates were 69% (95% CI, 54% to 80%) and 33% (95% CI, 21% to 46%). Median PFS was 8 months (95% CI, 6.0 to 10.7 months). Twelve- and 24-month overall survival (OS) rates were 68% (95% CI, 53% to 79%) and 35% (95% CI, 22% to 48%). Median OS was 16.1 months (95% CI, 13.1 to 23.2 months). PFS and OS were longer in patients with tumors with O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation (13.4 and 23.2 months) versus those without MGMT promoter methylation (3.4 and 13.1 months). The combination of cilengitide with temozolomide and radiotherapy was well tolerated, with no additional toxicity. No pharmacokinetic interactions between temozolomide and cilengitide were identified. CONCLUSION: Compared with historical controls, the addition of concomitant and adjuvant cilengitide to standard chemoradiotherapy demonstrated promising activity in patients with glioblastoma with MGMT promoter methylation.


Assuntos
Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/terapia , Dacarbazina/análogos & derivados , Glioblastoma/mortalidade , Glioblastoma/terapia , Venenos de Serpentes/administração & dosagem , Adulto , Idoso , Antineoplásicos Alquilantes/administração & dosagem , Antineoplásicos Alquilantes/efeitos adversos , Biópsia por Agulha , Neoplasias Encefálicas/patologia , Terapia Combinada , Intervalos de Confiança , Dacarbazina/administração & dosagem , Dacarbazina/efeitos adversos , Intervalo Livre de Doença , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Seguimentos , Glioblastoma/patologia , Humanos , Imuno-Histoquímica , Infusões Intravenosas , Estimativa de Kaplan-Meier , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Procedimentos Neurocirúrgicos/métodos , Probabilidade , Radioterapia Adjuvante , Radioterapia Conformacional , Medição de Risco , Venenos de Serpentes/efeitos adversos , Análise de Sobrevida , Temozolomida , Resultado do Tratamento
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