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1.
Elife ; 122023 09 12.
Artigo em Inglês | MEDLINE | ID: mdl-37698546

RESUMO

Infection with Influenza A virus (IAV) causes the well-known symptoms of the flu, including fever, loss of appetite, and excessive sleepiness. These responses, mediated by the brain, will normally disappear once the virus is cleared from the system, but a severe respiratory virus infection may cause long-lasting neurological disturbances. These include encephalitis lethargica and narcolepsy. The mechanisms behind such long lasting changes are unknown. The hypothalamus is a central regulator of the homeostatic response during a viral challenge. To gain insight into the neuronal and non-neuronal molecular changes during an IAV infection, we intranasally infected mice with an H1N1 virus and extracted the brain at different time points. Using single-nucleus RNA sequencing (snRNA-seq) of the hypothalamus, we identify transcriptional effects in all identified cell populations. The snRNA-seq data showed the most pronounced transcriptional response at 3 days past infection, with a strong downregulation of genes across all cell types. General immune processes were mainly impacted in microglia, the brain resident immune cells, where we found increased numbers of cells expressing pro-inflammatory gene networks. In addition, we found that most neuronal cell populations downregulated genes contributing to the energy homeostasis in mitochondria and protein translation in the cytosol, indicating potential reduced cellular and neuronal activity. This might be a preventive mechanism in neuronal cells to avoid intracellular viral replication and attack by phagocytosing cells. The change of microglia gene activity suggest that this is complemented by a shift in microglia activity to provide increased surveillance of their surroundings.


When you are ill, your behaviour changes. You sleep more, eat less and are less likely to go out and be active. This behavioural change is called the 'sickness response' and is believed to help the immune system fight infection. An area of the brain called the hypothalamus helps to regulate sleep and appetite. Previous research has shown that when humans are ill, the immune system sends signals to the hypothalamus, likely initiating the sickness response. However, it was not clear which brain cells in the hypothalamus are involved in the response and how long after infection the brain returns to its normal state. To better understand the sickness response, Lemcke et al. infected mice with influenza then extracted and analysed brain tissue at different timepoints. The experiments showed that the major changes to gene expression in the hypothalamus early during an influenza infection are not happening in neurons ­ the cells in the brain that transmit electrical signals and usually control behaviour. Instead, it is cells called glia ­ which provide support and immune protection to the neurons ­ that change during infection. The findings suggest that these cells prepare to protect the neurons from influenza should the virus enter the brain. Lemcke et al. also found that the brain takes a long time to go back to normal after an influenza infection. In infected mice, molecular changes in brain cells could be detected even after the influenza infection had been cleared from the respiratory system. In the future, these findings may help to explain why some people take longer than others to fully recover from viral infections such as influenza and aid development of medications that speed up recovery.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana , Animais , Camundongos , Humanos , Hipotálamo , Núcleo Solitário , Apetite
2.
J Exp Clin Cancer Res ; 42(1): 106, 2023 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-37118819

RESUMO

BACKGROUND: The malaria protein VAR2CSA binds oncofetal chondroitin sulfate (ofCS), a unique chondroitin sulfate, expressed on almost all mammalian cancer cells. Previously, we produced a bispecific construct targeting ofCS and human T cells based on VAR2CSA and anti-CD3 (V-aCD3Hu). V-aCD3Hu showed efficacy against xenografted tumors in immunocompromised mice injected with human immune cells at the tumor site. However, the complex effects potentially exerted by the immune system as a result of the treatment cannot occur in mice without an immune system. Here we investigate the efficacy of V-aCD3Mu as a monotherapy and combined with immune checkpoint inhibitors in mice with a fully functional immune system. METHODS: We produced a bispecific construct consisting of a recombinant version of VAR2CSA coupled to an anti-murine CD3 single-chain variable fragment. Flow cytometry and ELISA were used to check cell binding capabilities and the therapeutic effect was evaluated in vitro in a killing assay. The in vivo efficacy of V-aCD3Mu was then investigated in mice with a functional immune system and established or primary syngeneic tumors in the immunologically "cold" 4T1 mammary carcinoma, B16-F10 malignant melanoma, the pancreatic KPC mouse model, and in the immunologically "hot" CT26 colon carcinoma model. RESULTS: V-aCD3Mu had efficacy as a monotherapy, and the combined treatment of V-aCD3Mu and an immune checkpoint inhibitor showed enhanced effects resulting in the complete elimination of solid tumors in the 4T1, B16-F10, and CT26 models. This anti-tumor effect was abscopal and accompanied by a systemic increase in memory and activated cytotoxic and helper T cells. The combined treatment also led to a higher percentage of memory T cells in the tumor without an increase in regulatory T cells. In addition, we observed partial protection against re-challenge in a melanoma model and full protection in a breast cancer model. CONCLUSIONS: Our findings suggest that V-aCD3Mu combined with an immune checkpoint inhibitor renders immunologically "cold" tumors "hot" and results in tumor elimination. Taken together, these data provide proof of concept for the further clinical development of V-aCD3 as a broad cancer therapy in combination with an immune checkpoint inhibitor.


Assuntos
Anticorpos Biespecíficos , Carcinoma , Melanoma Experimental , Humanos , Camundongos , Animais , Sulfatos de Condroitina/farmacologia , Sulfatos de Condroitina/metabolismo , Memória Imunológica , Inibidores de Checkpoint Imunológico , Melanoma Experimental/tratamento farmacológico , Carcinoma/tratamento farmacológico , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/uso terapêutico , Linhagem Celular Tumoral , Mamíferos/metabolismo
3.
bioRxiv ; 2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38168225

RESUMO

Head-mounted miniscopes have allowed for functional fluorescence imaging in freely moving animals. However, current capabilities of state-of-the-art technology can record only up to two, spectrally distinct fluorophores. This severely limits the number of cell types identifiable in a functional imaging experiment. Here we present a pipeline that enables the distinction of nine neuronal subtypes from regions defined by behaviorally relevant cells during in vivo GCaMP imaging. These subtypes are identified utilizing unique fluorophores that are co-expressed with GCaMP, unmixed by spectral imaging on a confocal microscope and co-registering these spectral fingerprints with functional data obtained on miniaturized microscopes. This method facilitates detailed analyses of circuit-level encoding of behavior.

4.
NPJ Sci Learn ; 7(1): 29, 2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36302785

RESUMO

A child's environment is thought to be composed of different levels that interact with their individual genetic propensities. However, studies have not tested this theory comprehensively across multiple environmental levels. Here, we quantify the contributions of child, parent, school, neighbourhood, district, and municipality factors to achievement, and investigate interactions between polygenic indices for educational attainment (EA-PGI) and environmental levels. We link population-wide administrative data on children's standardised test results, schools and residential identifiers to the Norwegian Mother, Father, and Child Cohort Study (MoBa), which includes >23,000 genotyped parent-child trios. We test for gene-environment interactions using multilevel models with interactions between EA-PGI and random effects for school and residential environments (thus remaining agnostic to specific features of environments). We use parent EA-PGI to control for gene-environment correlation. We found an interaction between students' EA-PGI and schools suggesting compensation: higher-performing schools can raise overall achievement without leaving children with lower EA-PGI behind. Differences between schools matter more for students with lower EA-PGI, explaining 4 versus 2% of the variance in achievement for students 2 SD below versus 2 SD above the mean EA-PGI. Neighbourhood, district, and municipality variation contribute little to achievement (<2% of the variance collectively), and do not interact with children's individual EA-PGI. Policy to reduce social inequality in achievement in Norway should focus on tackling unequal support across schools for children with difficulties.

5.
J Child Psychol Psychiatry ; 63(10): 1174-1185, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35789088

RESUMO

BACKGROUND: Children with ADHD tend to achieve less than their peers in school. It is unknown whether schools moderate this association. Nonrandom selection of children into schools related to variations in their ADHD risk poses a methodological problem. METHODS: We linked data on ADHD symptoms of inattention and hyperactivity and parent-child ADHD polygenic scores (PGS) from the Norwegian Mother, Father, and Child Cohort Study (MoBa) to achievement in standardised tests and school identifiers. We estimated interactions of schools with individual differences between students in inattention, hyperactivity, and ADHD-PGS using multilevel models with random slopes for ADHD effects on achievement over schools. In our PGS analyses, we adjust for parental selection of schools by adjusting for parental ADHD-PGS (a within-family PGS design). We then tested whether five school sociodemographic measures explained any interactions. RESULTS: Analysis of up to 23,598 students attending 2,579 schools revealed interactions between school and ADHD effects on achievement. The variability between schools in the effects of inattention, hyperactivity and within-family ADHD-PGS on achievement was 0.08, 0.07 and 0.05 SDs, respectively. For example, the average effect of inattention on achievement was ß = -0.23 (SE = 0.009), but in 2.5% of schools with the weakest effects, the value was -0.07 or less. ADHD has a weaker effect on achievement in higher-performing schools. Schools make more of a difference to the achievements of students with higher levels of ADHD, explaining over four times as much variance in achievement for those with high versus average inattention symptoms. School sociodemographic measures could not explain the ADHD-by-school interactions. CONCLUSIONS: Although ADHD symptoms and genetic risk tend to hinder achievement, schools where their effects are weaker do exist. Differences between schools in support for children with ADHD should be evened out.


Assuntos
Sucesso Acadêmico , Transtorno do Deficit de Atenção com Hiperatividade , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtorno do Deficit de Atenção com Hiperatividade/genética , Estudos de Coortes , Escolaridade , Humanos , Instituições Acadêmicas
6.
Biochim Biophys Acta Biomembr ; 1864(6): 183884, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-35182589

RESUMO

Nanodiscs are used to stabilize membrane proteins in a lipid environment and enable investigations of the function and structure of these. Membrane proteins are often only available in small amounts, and thus the stability and ease of use of the nanodiscs are essential. We have recently explored circularizing and supercharging membrane scaffolding proteins (MSPs) for nanodisc formation and found increased temporal stability at elevated temperatures. In the present study, we investigate six different supercharged MSPs and their ability to form nanodiscs: three covalently circularized and the three non-circularized, linear versions. Using standard reconstitution protocols using cholate as the reconstitution detergent, we found that two of the linear constructs formed multiple lipid-protein species, whereas adding n-Dodecyl-B-D-maltoside (DDM) with the cholate in the reconstitution gave rise to single-species nanodisc formation for these MSPs. For all MSPs, the formed nanodiscs were analyzed by small-angle X-ray scattering (SAXS), which showed similar structures for each MSP, respectively, suggesting that the structures of the formed nanodiscs are independent of the initial DDM content, as long as cholate is present. Lastly, we incorporated the membrane protein proteorhodopsin into the supercharged nanodiscs and observed a considerable increase in incorporation yield with the addition of DDM. For the three circularized MSPs, a single major species appeared in the size exclusion chromatography (SEC) chromatogram, suggesting monodisperse nanodiscs with proteorhodopsin incorporated, which is in strong contrast to the samples without DDM showing almost no incorporation and high polydispersity.


Assuntos
Bicamadas Lipídicas , Proteínas de Membrana , Colatos , Detergentes/química , Bicamadas Lipídicas/química , Proteínas de Membrana/química , Espalhamento a Baixo Ângulo , Difração de Raios X
7.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34504004

RESUMO

Pentameric ligand-gated ion channels undergo subtle conformational cycling to control electrochemical signal transduction in many kingdoms of life. Several crystal structures have now been reported in this family, but the functional relevance of such models remains unclear. Here, we used small-angle neutron scattering (SANS) to probe ambient solution-phase properties of the pH-gated bacterial ion channel GLIC under resting and activating conditions. Data collection was optimized by inline paused-flow size-exclusion chromatography, and exchanging into deuterated detergent to hide the micelle contribution. Resting-state GLIC was the best-fit crystal structure to SANS curves, with no evidence for divergent mechanisms. Moreover, enhanced-sampling molecular-dynamics simulations enabled differential modeling in resting versus activating conditions, with the latter corresponding to an intermediate ensemble of both the extracellular and transmembrane domains. This work demonstrates state-dependent changes in a pentameric ion channel by SANS, an increasingly accessible method for macromolecular characterization with the coming generation of neutron sources.


Assuntos
Proteínas de Bactérias/química , Ativação do Canal Iônico , Canais Iônicos de Abertura Ativada por Ligante/química , Nêutrons , Multimerização Proteica , Estrutura Quaternária de Proteína , Espalhamento a Baixo Ângulo , Cianobactérias/metabolismo , Simulação de Dinâmica Molecular
8.
Anal Chem ; 93(37): 12698-12706, 2021 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-34498849

RESUMO

Isothermal titration calorimetry (ITC) is a widely used method to determine binding affinities and thermodynamics in ligand-receptor interactions, but it also has the capability of providing detailed information on much more complex events. However, the lack of available methods to analyze ITC data is limiting the use of the technique in such multifaceted cases. Here, we present the software ANISPROU. Through a semi-empirical approach that allows for extraction of quantitative information from complex ITC data, ANISPROU solves an inverse problem where three parameters describing a set of predefined functions must be found. In analogy to strategies adopted in other scientific fields, such as geophysics, imaging, and many others, it employs an optimization algorithm which minimizes the difference between calculated and experimental data. In contrast to the existing methods, ANISPROU provides automated and objective analysis of ITC data on sodium dodecyl sulfate (SDS)-induced protein unfolding, and in addition, more information can be extracted from the data. Here, data series on SDS-mediated protein unfolding is analyzed, and binding isotherms and thermodynamic information on the unfolding events are extracted. The obtained binding isotherms as well as the enthalpy of different events are similar to those obtained using the existing manual methods, but our methodology ensures a more robust result, as the entire data set is used instead of single data points. We foresee that ANISPROU will be useful in other cases with complex enthalpograms, for example, in cases with coupled interactions in biomolecular, polymeric, and amphiphilic systems including cases where both structural changes and interactions occur simultaneously.


Assuntos
Tensoativos , Calorimetria , Ligantes , Ligação Proteica , Dodecilsulfato de Sódio , Termodinâmica
9.
Child Dev ; 92(5): 2089-2105, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33948952

RESUMO

Although attention deficit hyperactivity disorder (ADHD) is among the most heritable psychiatric childhood disorders, social and gene-environment interactions seemingly play an important role in the etiology of ADHD. Consistent with this, this study finds that School-Wide Positive Behavioral Interventions and Supports (SWPBIS) reduced the likelihood of pharmacotherapeutic treatment for ADHD at age 14-16 by 12%, using population-wide Norwegian register data and a difference-in-difference design (N = 698,364, birth cohorts 1990-2002, 48.7% girls, 5.7% immigrant background). At-risk students in schools with high fidelity of implementation are driving these intervention effects. Overall, the findings indicate that children with a genetic disposition for ADHD are more likely to avoid medical treatment in an organized and predictable school setting with a focus on positive reinforcement.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/terapia , Terapia Comportamental , Criança , Feminino , Humanos , Masculino , Sistema de Registros , Instituições Acadêmicas , Estudantes
10.
Nat Commun ; 12(1): 1461, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33674575

RESUMO

The polyglutamine expansion of huntingtin (mHTT) causes Huntington disease (HD) and neurodegeneration, but the mechanisms remain unclear. Here, we found that mHtt promotes ribosome stalling and suppresses protein synthesis in mouse HD striatal neuronal cells. Depletion of mHtt enhances protein synthesis and increases the speed of ribosomal translocation, while mHtt directly inhibits protein synthesis in vitro. Fmrp, a known regulator of ribosome stalling, is upregulated in HD, but its depletion has no discernible effect on protein synthesis or ribosome stalling in HD cells. We found interactions of ribosomal proteins and translating ribosomes with mHtt. High-resolution global ribosome footprint profiling (Ribo-Seq) and mRNA-Seq indicates a widespread shift in ribosome occupancy toward the 5' and 3' end and unique single-codon pauses on selected mRNA targets in HD cells, compared to controls. Thus, mHtt impedes ribosomal translocation during translation elongation, a mechanistic defect that can be exploited for HD therapeutics.


Assuntos
Proteína Huntingtina/genética , Proteína Huntingtina/metabolismo , Doença de Huntington/genética , Doença de Huntington/metabolismo , Biossíntese de Proteínas , Ribossomos/metabolismo , Animais , Linhagem Celular , Modelos Animais de Doenças , Fibroblastos , Proteína do X Frágil da Deficiência Intelectual/genética , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Camundongos , Neurônios/metabolismo , Ribossomos/genética , Fatores de Transcrição/metabolismo , Transcriptoma , Regulação para Cima
11.
Front Cell Dev Biol ; 8: 749, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32984308

RESUMO

Circulating tumor cells (CTCs) are accessible by liquid biopsies via an easy blood draw. They represent not only the primary tumor site, but also potential metastatic lesions, and could thus be an attractive supplement for cancer diagnostics. However, the analysis of rare CTCs in billions of normal blood cells is still technically challenging and novel specific CTC markers are needed. The formation of metastasis is a complex process supported by numerous molecular alterations, and thus novel CTC markers might be found by focusing on this process. One example of this is specific changes in the cancer cell glycocalyx, which is a network on the cell surface composed of carbohydrate structures. Proteoglycans are important glycocalyx components and consist of a protein core and covalently attached long glycosaminoglycan chains. A few CTC assays have already utilized proteoglycans for both enrichment and analysis of CTCs. Nonetheless, the biological function of proteoglycans on clinical CTCs has not been studied in detail so far. Therefore, the present review describes proteoglycan functions during the metastatic cascade to highlight their importance to CTCs. We also outline current approaches for CTC assays based on targeting proteoglycans by their protein cores or their glycosaminoglycan chains. Lastly, we briefly discuss important technical aspects, which should be considered for studying proteoglycans.

12.
Int J Mol Sci ; 21(7)2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32244341

RESUMO

Early detection and monitoring of cancer progression is key to successful treatment. Therefore, much research is invested in developing technologies, enabling effective and valuable use of non-invasive liquid biopsies. This includes the detection and analysis of circulating tumor cells (CTCs) from blood samples. Recombinant malaria protein VAR2CSA (rVAR2) binds a unique chondroitin sulfate modification present on the vast majority of cancers and thereby holds promise as a near-universal tumor cell-targeting reagent to isolate CTCs from complex blood samples. This study describes a technical approach for optimizing the coupling of rVAR2 to magnetic beads and the development of a CTC isolation platform targeting a range of different cancer cell lines. We investigate both direct and indirect approaches for rVAR2-mediated bead retrieval of cancer cells and conclude that an indirect capture approach is most effective for rVAR2-based cancer cell retrieval.


Assuntos
Antígenos de Protozoários/genética , Detecção Precoce de Câncer/métodos , Células Neoplásicas Circulantes/patologia , Linhagem Celular Tumoral , Sulfatos de Condroitina/metabolismo , Humanos , Magnetismo , Proteínas Recombinantes
13.
Int J Psychol ; 55 Suppl 1: 4-15, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30963574

RESUMO

Problem behaviour in schools may have detrimental effects both on students' well-being and academic achievement. A large literature has consistently found that school-wide positive behaviour support (SWPBS) successfully addresses social and behavioural problems. In this paper, we used population-wide longitudinal register data for all Norwegian primary schools and a difference-in-difference (DiD) design to evaluate effects of SWPBS on a number of primary and secondary outcomes, including indicators of externalising behaviour, school well-being, pull-out instruction, and academic achievement. Indications of reduced classroom noise were found. No other effects were detected. Analyses revealed important differences in outcomes between the intervention and control schools, independent of the implementation of SWPBS, and that a credible design like DiD is essential to handle such school differences.


Assuntos
Comportamento Infantil/psicologia , Adolescente , Criança , Feminino , Humanos , Estudos Longitudinais , Masculino , Sistema de Registros , Instituições Acadêmicas
14.
Cells ; 8(9)2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31466397

RESUMO

Diffuse gliomas are the most common primary malignant brain tumor. Although extracranial metastases are rarely observed, recent studies have shown the presence of circulating tumor cells (CTCs) in the blood of glioma patients, confirming that a subset of tumor cells are capable of entering the circulation. The isolation and characterization of CTCs could provide a non-invasive method for repeated analysis of the mutational and phenotypic state of the tumor during the course of disease. However, the efficient detection of glioma CTCs has proven to be challenging due to the lack of consistently expressed tumor markers and high inter- and intra-tumor heterogeneity. Thus, for this field to progress, an omnipresent but specific marker of glioma CTCs is required. In this article, we demonstrate how the recombinant malaria VAR2CSA protein (rVAR2) can be used for the capture and detection of glioma cell lines that are spiked into blood through binding to a cancer-specific oncofetal chondroitin sulfate (ofCS). When using rVAR2 pull-down from glioma cells, we identified a panel of proteoglycans, known to be essential for glioma progression. Finally, the clinical feasibility of this work is supported by the rVAR2-based isolation and detection of CTCs from glioma patient blood samples, which highlights ofCS as a potential clinical target for CTC isolation.


Assuntos
Antígenos de Protozoários/farmacologia , Biomarcadores Tumorais/sangue , Neoplasias Encefálicas/diagnóstico , Separação Celular/métodos , Glioma/diagnóstico , Células Neoplásicas Circulantes/metabolismo , Neoplasias Encefálicas/metabolismo , Contagem de Células/métodos , Linhagem Celular Tumoral , Proteoglicanas de Sulfatos de Condroitina/sangue , Glioma/metabolismo , Humanos , Estudo de Prova de Conceito , Proteínas Recombinantes/farmacologia
15.
Proc Natl Acad Sci U S A ; 115(34): E8047-E8056, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-30082388

RESUMO

Extending superresolution fluorescence microscopy to living animals has remained a challenging frontier ever since the first demonstration of STED (stimulated emission depletion) nanoscopy in the mouse visual cortex. The use of fluorescent proteins (FPs) in in vivo STED analyses has been limiting available fluorescence photon budgets and attainable image contrasts, in particular for far-red FPs. This has so far precluded the definition of subtle details in protein arrangements at sufficient signal-to-noise ratio. Furthermore, imaging with longer wavelengths holds promise for reducing photostress. Here, we demonstrate that a strategy based on enzymatic self-labeling of the HaloTag fusion protein by high-performance synthetic fluorophore labels provides a robust avenue to superior in vivo analysis with STED nanoscopy in the far-red spectral range. We illustrate our approach by mapping the nanoscale distributions of the abundant scaffolding protein PSD95 at the postsynaptic membrane of excitatory synapses in living mice. With silicon-rhodamine as the reporter fluorophore, we present imaging with high contrast and low background down to ∼70-nm lateral resolution in the visual cortex at ≤25-µm depth. This approach allowed us to identify and characterize the diversity of PSD95 scaffolds in vivo. Besides small round/ovoid shapes, a substantial fraction of scaffolds exhibited a much more complex spatial organization. This highly inhomogeneous, spatially extended PSD95 distribution within the disk-like postsynaptic density, featuring intricate perforations, has not been highlighted in cell- or tissue-culture experiments. Importantly, covisualization of the corresponding spine morphologies enabled us to contextualize the diverse PSD95 patterns within synapses of different orientations and sizes.


Assuntos
Proteína 4 Homóloga a Disks-Large/metabolismo , Proteínas Luminescentes/metabolismo , Imagem Óptica/métodos , Coloração e Rotulagem/métodos , Sinapses/metabolismo , Córtex Visual , Animais , Proteína 4 Homóloga a Disks-Large/genética , Proteínas Luminescentes/genética , Camundongos , Sinapses/genética , Córtex Visual/citologia , Córtex Visual/metabolismo , Proteína Vermelha Fluorescente
16.
Proc Natl Acad Sci U S A ; 115(11): E2634-E2643, 2018 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-29487216

RESUMO

Exposure of cultured primary neurons to preformed α-synuclein fibrils (PFFs) leads to the recruitment of endogenous α-synuclein and its templated conversion into fibrillar phosphorylated α-synuclein (pα-synF) aggregates resembling those involved in Parkinson's disease (PD) pathogenesis. Pα-synF was described previously as inclusions morphologically similar to Lewy bodies and Lewy neurites in PD patients. We discovered the existence of a conformationally distinct, nonfibrillar, phosphorylated α-syn species that we named "pα-syn*." We uniquely describe the existence of pα-syn* in PFF-seeded primary neurons, mice brains, and PD patients' brains. Through immunofluorescence and pharmacological manipulation we showed that pα-syn* results from incomplete autophagic degradation of pα-synF. Pα-synF was decorated with autophagic markers, but pα-syn* was not. Western blots revealed that pα-syn* was N- and C-terminally trimmed, resulting in a 12.5-kDa fragment and a SDS-resistant dimer. After lysosomal release, pα-syn* aggregates associated with mitochondria, inducing mitochondrial membrane depolarization, cytochrome C release, and mitochondrial fragmentation visualized by confocal and stimulated emission depletion nanoscopy. Pα-syn* recruited phosphorylated acetyl-CoA carboxylase 1 (ACC1) with which it remarkably colocalized. ACC1 phosphorylation indicates low ATP levels, AMPK activation, and oxidative stress and induces mitochondrial fragmentation via reduced lipoylation. Pα-syn* also colocalized with BiP, a master regulator of the unfolded protein response and a resident protein of mitochondria-associated endoplasmic reticulum membranes that are sites of mitochondrial fission and mitophagy. Pα-syn* aggregates were found in Parkin-positive mitophagic vacuoles and imaged by electron microscopy. Collectively, we showed that pα-syn* induces mitochondrial toxicity and fission, energetic stress, and mitophagy, implicating pα-syn* as a key neurotoxic α-syn species and a therapeutic target.


Assuntos
Autofagia/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Neurotoxinas , Doença de Parkinson/metabolismo , alfa-Sinucleína , Acetil-CoA Carboxilase/química , Acetil-CoA Carboxilase/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Química Encefálica , Técnicas de Cultura de Células , Células Cultivadas , Humanos , Lisossomos/metabolismo , Camundongos , Mitocôndrias , Neurotoxinas/química , Neurotoxinas/metabolismo , Neurotoxinas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , alfa-Sinucleína/toxicidade
17.
Nat Commun ; 9(1): 290, 2018 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-29348575

RESUMO

Ca2+ influx triggers the release of synaptic vesicles at the presynaptic active zone (AZ). A quantitative characterization of presynaptic Ca2+ signaling is critical for understanding synaptic transmission. However, this has remained challenging to establish at the required resolution. Here, we employ confocal and stimulated emission depletion (STED) microscopy to quantify the number (20-330) and arrangement (mostly linear 70 nm × 100-600 nm clusters) of Ca2+ channels at AZs of mouse cochlear inner hair cells (IHCs). Establishing STED Ca2+ imaging, we analyze presynaptic Ca2+ signals at the nanometer scale and find confined elongated Ca2+ domains at normal IHC AZs, whereas Ca2+ domains are spatially spread out at the AZs of bassoon-deficient IHCs. Performing 2D-STED fluorescence lifetime analysis, we arrive at estimates of the Ca2+ concentrations at stimulated IHC AZs of on average 25 µM. We propose that IHCs form bassoon-dependent presynaptic Ca2+-channel clusters of similar density but scalable length, thereby varying the number of Ca2+ channels amongst individual AZs.


Assuntos
Sinalização do Cálcio/fisiologia , Células Ciliadas Auditivas Internas/fisiologia , Microscopia/métodos , Nanotecnologia/métodos , Algoritmos , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo L/fisiologia , Células Ciliadas Auditivas Internas/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Confocal , Modelos Neurológicos , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/fisiologia , Sinapses/metabolismo , Sinapses/fisiologia , Transmissão Sináptica/genética , Transmissão Sináptica/fisiologia
18.
Sports Med ; 48(5): 1049-1058, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-28983866

RESUMO

Studies in sport and exercise medicine routinely use samples of highly trained individuals in order to understand what characterizes elite endurance performance, such as running economy and maximal oxygen uptake VO2max. However, it is not well understood in the literature that using such samples most certainly leads to biased findings and accordingly potentially erroneous conclusions because of endogenous selection bias. In this paper, I review the current literature on running economy and VO2max, and discuss the literature in light of endogenous selection bias. I demonstrate that the results in a large part of the literature may be misleading, and provide some practical suggestions as to how future studies may alleviate endogenous selection bias.


Assuntos
Consumo de Oxigênio/fisiologia , Resistência Física , Corrida , Viés de Seleção , Exercício Físico , Humanos
19.
Med Klin Intensivmed Notfmed ; 113(1): 33-44, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29116361

RESUMO

A growing number of patients with increasingly complex or specialized diseases are being treated in hospitals worldwide. The treatment requirements of some of these patients are exceeding the capacity of standard nursing units. However, the severity of these diseases or the treatment requirements for these specific clinical pictures do not always justify admission to an intensive care unit. For this reason, an increasing number of special units (intermediate care units) are being set up to offer highly specialized treatment and close monitoring, in order to fulfil an intermediate role between the standard care unit and the intensive care unit. The recommendations of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI) on the personnel, capacity, equipment and structure of these units are intended to provide the framework for the setting up and operation of intermediate care units in collaboration with experts on both an evidence-based and an expert-based basis (where scientific evidence is not available). Where only minimal or indirect evidence is available, patient safety is paramount in the formulation of the recommendation.


Assuntos
Medicina de Emergência , Unidades de Terapia Intensiva , Instituições para Cuidados Intermediários , Cuidados Críticos , Humanos
20.
Pneumologie ; 71(12): 849-919, 2017 12.
Artigo em Alemão | MEDLINE | ID: mdl-29216678

RESUMO

The present guideline is a new version and an update of the guideline for the diagnosis and treatment of asthma, which replaces the previous version for german speaking countries from the year 2006. The wealth of new data on the pathophysiology and the phenotypes of asthma, and the expanded spectrum of diagnostic and therapeutic options necessitated a new version and an update. This guideline presents the current, evidence-based recommendations for the diagnosis and treatment of asthma, for children and adolescents as well as for adults with asthma.


Assuntos
Asma/diagnóstico , Asma/terapia , Asma/classificação , Asma/etiologia , Áustria , Alemanha , Humanos , Prognóstico , Fatores de Risco , Sociedades Médicas
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