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1.
Elife ; 112022 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-35866628

RESUMO

G-protein-coupled receptors (GPCR) are present at the cell surface in different conformational and oligomeric states. However, how these states impact GPCRs biological function and therapeutic targeting remains incompletely known. Here, we investigated this issue in living cells for the CC chemokine receptor 5 (CCR5), a major receptor in inflammation and the principal entry co-receptor for Human Immunodeficiency Viruses type 1 (HIV-1). We used TIRF microscopy and a statistical method to track and classify the motion of different receptor subpopulations. We showed a diversity of ligand-free forms of CCR5 at the cell surface constituted of various oligomeric states and exhibiting transient Brownian and restricted motions. These forms were stabilized differently by distinct ligands. In particular, agonist stimulation restricted the mobility of CCR5 and led to its clustering, a feature depending on ß-arrestin, while inverse agonist stimulation exhibited the opposite effect. These results suggest a link between receptor activation and immobilization. Applied to HIV-1 envelope glycoproteins gp120, our quantitative analysis revealed agonist-like properties of gp120s. Distinct gp120s influenced CCR5 dynamics differently, suggesting that they stabilize different CCR5 conformations. Then, using a dimerization-compromized mutant, we showed that dimerization (i) impacts CCR5 precoupling to G proteins, (ii) is a pre-requisite for the immobilization and clustering of receptors upon activation, and (iii) regulates receptor endocytosis, thereby impacting the fate of activated receptors. This study demonstrates that tracking the dynamic behavior of a GPCR is an efficient way to link GPCR conformations to their functions, therefore improving the development of drugs targeting specific receptor conformations.


Assuntos
HIV-1 , Receptores CCR5 , Membrana Celular/metabolismo , HIV-1/fisiologia , Humanos , Ligantes , Multimerização Proteica , Receptores CCR5/metabolismo , Receptores Acoplados a Proteínas G/metabolismo
2.
PLoS Pathog ; 18(5): e1010335, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35622876

RESUMO

Macrophages (MΦ) are increasingly recognized as HIV-1 target cells involved in the pathogenesis and persistence of infection. Paradoxically, in vitro infection assays suggest that virus isolates are mostly T-cell-tropic and rarely MΦ-tropic. The latter are assumed to emerge under CD4+ T-cell paucity in tissues such as the brain or at late stage when the CD4 T-cell count declines. However, assays to qualify HIV-1 tropism use cell-free viral particles and may not fully reflect the conditions of in vivo MΦ infection through cell-to-cell viral transfer. Here, we investigated the capacity of viruses expressing primary envelope glycoproteins (Envs) with CCR5 and/or CXCR4 usage from different stages of infection, including transmitted/founder Envs, to infect MΦ by a cell-free mode and through cell-to-cell transfer from infected CD4+ T cells. The results show that most viruses were unable to enter MΦ as cell-free particles, in agreement with the current view that non-M-tropic viruses inefficiently use CD4 and/or CCR5 or CXCR4 entry receptors on MΦ. In contrast, all viruses could be effectively cell-to-cell transferred to MΦ from infected CD4+ T cells. We further showed that viral transfer proceeded through Env-dependent cell-cell fusion of infected T cells with MΦ targets, leading to the formation of productively infected multinucleated giant cells. Compared to cell-free infection, infected T-cell/MΦ contacts showed enhanced interactions of R5 M- and non-M-tropic Envs with CD4 and CCR5, resulting in a reduced dependence on receptor expression levels on MΦ for viral entry. Altogether, our results show that virus cell-to-cell transfer overcomes the entry block of isolates initially defined as non-macrophage-tropic, indicating that HIV-1 has a more prevalent tropism for MΦ than initially suggested. This sheds light into the role of this route of virus cell-to-cell transfer to MΦ in CD4+ T cell rich tissues for HIV-1 transmission, dissemination and formation of tissue viral reservoirs.


Assuntos
Infecções por HIV , HIV-1 , Antígenos CD4/metabolismo , Linfócitos T CD4-Positivos , Infecções por HIV/metabolismo , HIV-1/metabolismo , Humanos , Macrófagos/metabolismo , Receptores CCR5/metabolismo , Internalização do Vírus
3.
Oncologist ; 27(5): 414-423, 2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35522558

RESUMO

BACKGROUND: Anaplastic oligodendrogliomas IDH-mutant and 1p/19q codeleted (AO) occasionally have a poor outcome. Herein we aimed at analyzing their characteristics. METHODS: We retrospectively analyzed the characteristics of 44 AO patients with a cancer-specific survival <5 years (short-term survivors, STS) and compared them with those of 146 AO patients with a survival ≥5 years (classical survivors, CS) included in the POLA network. RESULTS: Compared to CS, STS were older (P = .0001), less frequently presented with isolated seizures (P < .0001), more frequently presented with cognitive dysfunction (P < .0001), had larger tumors (P = .= .003), a higher proliferative index (P = .= .0003), and a higher number of chromosomal arm abnormalities (P = .= .02). Regarding treatment, STS less frequently underwent a surgical resection than CS (P = .= .0001) and were more frequently treated with chemotherapy alone (P = .= .009) or with radiotherapy plus temozolomide (P = .= .05). Characteristics independently associated with STS in multivariate analysis were cognitive dysfunction, a number of mitosis > 8, and the absence of tumor resection. Based on cognitive dysfunction, type of surgery, and number of mitosis, patients could be classified into groups of standard (18%) and high (62%) risk of <5 year survival. CONCLUSION: The present study suggests that although STS poor outcome appears to largely result from a more advanced disease at diagnosis, surgical resection may be particularly important in this population.


Assuntos
Neoplasias Encefálicas , Oligodendroglioma , Neoplasias Encefálicas/patologia , Aberrações Cromossômicas , Humanos , Oligodendroglioma/genética , Estudos Retrospectivos , Sobreviventes , Temozolomida/uso terapêutico
4.
Viruses ; 13(7)2021 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-34372601

RESUMO

The chemokine receptor CCR5 is a key player in HIV-1 infection. The cryo-EM 3D structure of HIV-1 envelope glycoprotein (Env) subunit gp120 in complex with CD4 and CCR5 has provided important structural insights into HIV-1/host cell interaction, yet it has not explained the signaling properties of Env nor the fact that CCR5 exists in distinct forms that show distinct Env binding properties. We used classical molecular dynamics and site-directed mutagenesis to characterize the CCR5 conformations stabilized by four gp120s, from laboratory-adapted and primary HIV-1 strains, and which were previously shown to bind differentially to distinct CCR5 forms and to exhibit distinct cellular tropisms. The comparative analysis of the simulated structures reveals that the different gp120s do indeed stabilize CCR5 in different conformational ensembles. They differentially reorient extracellular loops 2 and 3 of CCR5 and thus accessibility to the transmembrane binding cavity. They also reshape this cavity differently and give rise to different positions of intracellular ends of transmembrane helices 5, 6 and 7 of the receptor and of its third intracellular loop, which may in turn influence the G protein binding region differently. These results suggest that the binding of gp120s to CCR5 may have different functional outcomes, which could result in different properties for viruses.


Assuntos
Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/fisiologia , Receptores CCR5/química , Receptores CCR5/metabolismo , Linhagem Celular , Proteína gp120 do Envelope de HIV/classificação , Proteína gp120 do Envelope de HIV/genética , HIV-1/química , Humanos , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Ligação Proteica , Receptores CCR5/genética , Tropismo Viral
5.
Physiol Rep ; 9(11): e14591, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34057319

RESUMO

Soldiers on military expeditions usually fail to compensate for the increase in energy expenditure, with potential deleterious consequences. We therefore analyzed the characteristics of energy compensation in 12 male soldiers, during a 15-day expedition in the cold, while alleviating some of the contextual limitations of food intake (~20-MJ daily bags of easy-to-use, highly palatable and familiar foods with multiple and long breaks allowed during the day). Body and fat mass losses were low and moderate, respectively (-1.13 ± 1.42% and -19.5 ± 15.6%, respectively, p < .021). Mean energy intake (EI) was high (~16.3 MJ) and increased at each third of the expedition (15.3 ± 2.1, 16.1 ± 2.1, and 17.6 ± 2.0 for D1-5, D6-10 and D11-15, respectively, p < .012). This resulted in reaching a neutral energy balance as soon as the D6 to 10 period and reaching normal energy availability during D11 to 15. Participants only increased their EI during the mid-day (10:00-14:00) period (p = .002) whereas hunger and thirst only increased in the morning, with higher scores during D11-15 than D1-5 (p < .009). Last, the reward value of sweet foods was also higher during D11-15 than during D1-5 (p = .026). The changes in body mass were positively associated with EI (r = 0.598, p = .040) and carbohydrate intake (r = 0.622, p = .031). This study indicates that complete energy compensation can be reached in challenging field conditions when food intake is facilitated, offering some guidelines to limit energy deficit during operational missions.


Assuntos
Temperatura Baixa/efeitos adversos , Ingestão de Alimentos/fisiologia , Metabolismo Energético , Militares , Adulto , Ingestão de Energia/fisiologia , Metabolismo Energético/fisiologia , Humanos , Masculino , Esforço Físico/fisiologia , Adulto Jovem
6.
PLoS Pathog ; 17(4): e1009526, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33872329

RESUMO

HIV-1 infects CD4 T lymphocytes (CD4TL) through binding the chemokine receptors CCR5 or CXCR4. CXCR4-using viruses are considered more pathogenic, linked to accelerated depletion of CD4TL and progression to AIDS. However, counterexamples to this paradigm are common, suggesting heterogeneity in the virulence of CXCR4-using viruses. Here, we investigated the role of the CXCR4 chemokine CXCL12 as a driving force behind virus virulence. In vitro, CXCL12 prevents HIV-1 from binding CXCR4 and entering CD4TL, but its role in HIV-1 transmission and propagation remains speculative. Through analysis of thirty envelope glycoproteins (Envs) from patients at different stages of infection, mostly treatment-naïve, we first interrogated whether sensitivity of viruses to inhibition by CXCL12 varies over time in infection. Results show that Envs resistant (RES) to CXCL12 are frequent in patients experiencing low CD4TL levels, most often late in infection, only rarely at the time of primary infection. Sensitivity assays to soluble CD4 or broadly neutralizing antibodies further showed that RES Envs adopt a more closed conformation with distinct antigenicity, compared to CXCL12-sensitive (SENS) Envs. At the level of the host cell, our results suggest that resistance is not due to improved fusion or binding to CD4, but owes to viruses using particular CXCR4 molecules weakly accessible to CXCL12. We finally asked whether the low CD4TL levels in patients are related to increased pathogenicity of RES viruses. Resistance actually provides viruses with an enhanced capacity to enter naive CD4TL when surrounded by CXCL12, which mirrors their situation in lymphoid organs, and to deplete bystander activated effector memory cells. Therefore, RES viruses seem more likely to deregulate CD4TL homeostasis. This work improves our understanding of the pathophysiology and the transmission of HIV-1 and suggests that RES viruses' receptors could represent new therapeutic targets to help prevent CD4TL depletion in HIV+ patients on cART.


Assuntos
Antivirais/metabolismo , Quimiocina CXCL12/metabolismo , Infecções por HIV/virologia , HIV-1/patogenicidade , Receptores CXCR4/metabolismo , Linfócitos T CD4-Positivos/virologia , Infecções por HIV/fisiopatologia , Infecções por HIV/transmissão , HIV-1/fisiologia , Homeostase , Humanos , Proteínas do Envelope Viral/metabolismo , Virulência
7.
Acta Neuropathol Commun ; 8(1): 198, 2020 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-33225991

RESUMO

The brain pathology of Alzheimer's disease (AD) is characterized by the misfolding and aggregation of both the amyloid beta (Aß) peptide and hyperphosphorylated forms of the tau protein. Initial Aß deposition is considered to trigger a sequence of deleterious events contributing to tau pathology, neuroinflammation and ultimately causing the loss of synapses and neurons. To assess the effect of anti-Aß immunization in this context, we generated a mouse model by overexpressing the human tau protein in the hippocampus of 5xFAD mice. Aß plaque deposition combined with human tau overexpression leads to an array of pathological manifestations including the formation of tau-positive dystrophic neurites and accumulation of hyperphosphorylated tau at the level of neuritic plaques. Remarkably, the presence of human tau reduces microglial clustering in proximity to the Aß plaques, which may affect the barrier role of microglia. In this mouse model, continuous administration of anti-Aß antibodies enhances the clustering of microglial cells even in the presence of tau. Anti-Aß immunization increases plaque compaction, reduces the spread of tau in the hippocampal formation and prevents the formation of tau-positive dystrophic neurites. However, the treatment does not significantly reduce tau-induced neurodegeneration in the dentate gyrus. These results highlight that anti-Aß immunization is able to enhance microglial activity around neuritic plaques, mitigating part of the tau-induced pathological manifestations.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/imunologia , Anticorpos/farmacologia , Região CA3 Hipocampal/metabolismo , Giro Denteado/metabolismo , Microglia/patologia , Placa Amiloide/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Animais , Região CA3 Hipocampal/patologia , Giro Denteado/patologia , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Imunização Passiva , Camundongos , Camundongos Transgênicos , Placa Amiloide/patologia , Presenilina-1/genética
8.
Commun Biol ; 3(1): 364, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32647232

RESUMO

Sub-cellular trace element quantifications of nano-heterogeneities in brain tissues offer unprecedented ways to explore at elemental level the interplay between cellular compartments in neurodegenerative pathologies. We designed a quasi-correlative method for analytical nanoimaging of the substantia nigra, based on transmission electron microscopy and synchrotron X-ray fluorescence. It combines ultrastructural identifications of cellular compartments and trace element nanoimaging near detection limits, for increased signal-to-noise ratios. Elemental composition of different organelles is compared to cytoplasmic and nuclear compartments in dopaminergic neurons of rat substantia nigra. They exhibit 150-460 ppm of Fe, with P/Zn/Fe-rich nucleoli in a P/S-depleted nuclear matrix and Ca-rich rough endoplasmic reticula. Cytoplasm analysis displays sub-micron Fe/S-rich granules, including lipofuscin. Following AAV-mediated overexpression of α-synuclein protein associated with Parkinson's disease, these granules shift towards higher Fe concentrations. This effect advocates for metal (Fe) dyshomeostasis in discrete cytoplasmic regions, illustrating the use of this method to explore neuronal dysfunction in brain diseases.


Assuntos
Neurônios Dopaminérgicos/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Organelas/metabolismo , Doença de Parkinson/patologia , Substância Negra/metabolismo , Oligoelementos/metabolismo , alfa-Sinucleína/metabolismo , Animais , Feminino , Microscopia Eletrônica de Transmissão/métodos , Doença de Parkinson/metabolismo , Ratos , Ratos Sprague-Dawley , Espectrometria por Raios X/métodos , Síncrotrons/instrumentação
9.
Appl Physiol Nutr Metab ; 45(9): 968-977, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32187499

RESUMO

We assessed energy compensation, appetite, and reward value of foods during a 14-day military expedition in Greenland realized by 12 male French soldiers, during which energy compensation was optimized by providing them with easy-to-eat palatable foods in excess. Although daily energy expenditure (estimated by accelerometry) stayed relatively constant throughout the expedition (15 ± 9 MJ·day-1), energy intake (EI; estimated by self-reported diaries) was 17% higher during the D8-D14 period compared with the D1-D7 period, leading to a neutral energy balance (EB). Body fat mass (BFM) significantly decreased (-1.0 ± 0.7 kg, p < 0.001) but not body mass (BM). Neither hunger scores (assessed by visual analog scales) nor components of the reward value of food (explicit liking (EL) and food preference) were significantly altered. However, changes in EL at D10 were positively correlated with changes in BM (r = 0.600, p < 0.05) and BFM (r = 0.680, p < 0.05) and changes in hunger in the EI of the relevant period (r = 0.743, p < 0.01 for D1-D7, r = 0.652, p < 0.05 for D8-14). This study shows that the negative EB and BM loss can be attenuated by an appropriate food supply and that subjective components of eating behaviour, such as hunger and EL, may be useful to predict the magnitude of energy compensation. Novelty Energy intake increases during of a 14-day expedition in the cold. Energy compensation was likely facilitated by providing participants with easy-to-eat palatable and familiar foods. Hunger scores and EL for energy-dense foods were associated with high EIs and low BM changes.


Assuntos
Temperatura Baixa , Metabolismo Energético , Comportamento Alimentar , Adulto , Apetite , Ingestão de Energia , Expedições , Preferências Alimentares , Groenlândia , Humanos , Fome , Masculino , Pessoa de Meia-Idade , Militares
10.
Neurology ; 94(10): e1027-e1039, 2020 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-31907289

RESUMO

OBJECTIVE: Real-life studies on patients with primary CNS lymphoma (PCNSL) are scarce. Our objective was to analyze, in a nationwide population-based study, the current medical practice in the management of PCNSL. METHODS: The French oculo-cerebral lymphoma network (LOC) database prospectively records all newly diagnosed PCNSL cases from 32 French centers. Data of patients diagnosed between 2011 and 2016 were retrospectively analyzed. RESULTS: We identified 1,002 immunocompetent patients (43% aged >70 years, median Karnofsky Performance Status [KPS] 60). First-line treatment was high-dose methotrexate-based chemotherapy in 92% of cases, with an increasing use of rituximab over time (66%). Patients <60 years of age received consolidation treatment in 77% of cases, consisting of whole-brain radiotherapy (WBRT) (54%) or high-dose chemotherapy with autologous stem cell transplantation (HCT-ASCT) (23%). Among patients >60 years of age, WBRT and HCT-ASCT consolidation were administered in only 9% and 2%, respectively. The complete response rate to initial chemotherapy was 50%. Median progression-free survival was 10.5 months. For relapse, second-line chemotherapy, HCT-ASCT, WBRT, and palliative care were offered to 55%, 17%, 10%, and 18% of patients, respectively. The median, 2-year, and 5-year overall survival was 25.3 months, 51%, and 38%, respectively (<60 years: not reached [NR], 70%, and 61%; >60 years: 15.4 months, 44%, and 28%). Age, KPS, sex, and response to induction CT were independent prognostic factors in multivariate analysis. CONCLUSIONS: Our study confirms the increasing proportion of elderly within the PCNSL population and shows comparable outcome in this population-based study with those reported by clinical trials, reflecting a notable application of recent PCNSL advances in treatment.


Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Antineoplásicos Imunológicos/farmacologia , Neoplasias do Sistema Nervoso Central/terapia , Irradiação Craniana/estatística & dados numéricos , Linfoma/terapia , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Transplante de Células-Tronco/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , Neoplasias do Sistema Nervoso Central/epidemiologia , Terapia Combinada , Bases de Dados Factuais , França/epidemiologia , Humanos , Linfoma/epidemiologia , Metotrexato/farmacologia , Pessoa de Meia-Idade , Intervalo Livre de Progressão , Estudos Retrospectivos , Rituximab/farmacologia , Transplante Autólogo , Adulto Jovem
11.
J Virol ; 94(1)2019 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-31619555

RESUMO

Soluble recombinant native-like (NL) envelope glycoprotein (Env) trimers of various human immunodeficiency virus type 1 (HIV-1) genotypes are being developed as vaccine candidates aimed at the induction of broadly neutralizing antibodies (bNAbs). The prototypic design, designated BG505 SOSIP.664, incorporates an intersubunit disulfide bond (SOS) to covalently link the gp120 and gp41 ectodomain (gp41ECTO) subunits and a point substitution, I559P (IP), to further stabilize the gp41ECTO components. Without the SOS and IP changes, proteolytically cleaved trimers tend to disintegrate into their constituent gp120 and gp41ECTO subunits. We show, however, that NL trimers lacking the SOS and/or IP change can be affinity purified in amounts sufficient for analyses of their antigenicity and thermal stability. In general, these trimer variants have properties highly comparable to those of the fully stabilized SOSIP.664 version. We conclude that the major effect of the SOS and IP changes is to substantially increase trimer stability during and after the expression process, thereby allowing useful amounts to be produced. However, once the trimers have been purified, the SOS and IP changes have only subtle impacts on thermostability and the antigenicity of bNAb and other epitopes.IMPORTANCE Recombinant trimeric proteins based on HIV-1 env genes are being developed for vaccine trials in humans. A feature of these proteins is their mimicry of the envelope glycoprotein structure on virus particles that is targeted by neutralizing antibodies, i.e., antibodies that prevent cells from becoming infected. One vaccine concept under exploration is that recombinant trimers may be able to elicit virus-neutralizing antibodies when delivered as immunogens. A commonly used design is designated SOSIP.664, a term reflecting the sequence changes that are used to stabilize the trimers and allow their production in practically useful amounts. Here, we show that these stabilizing changes act to increase trimer yield during the biosynthesis process within the producer cell but have little impact on the properties of purified trimers.


Assuntos
Vacinas contra a AIDS/genética , Proteína gp120 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/genética , HIV-1/genética , Proteínas Recombinantes de Fusão/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Vacinas contra a AIDS/biossíntese , Animais , Anticorpos Neutralizantes/biossíntese , Células CHO , Cricetulus , Dissulfetos/química , Expressão Gênica , Genótipo , Células HEK293 , Anticorpos Anti-HIV/biossíntese , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/classificação , HIV-1/imunologia , Humanos , Mutação Puntual , Domínios Proteicos , Estabilidade Proteica , Proteólise , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/imunologia , Temperatura , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia
12.
PLoS Pathog ; 14(12): e1007432, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30521629

RESUMO

CCR5 plays immune functions and is the coreceptor for R5 HIV-1 strains. It exists in diverse conformations and oligomerization states. We interrogated the significance of the CCR5 structural diversity on HIV-1 infection. We show that envelope glycoproteins (gp120s) from different HIV-1 strains exhibit divergent binding levels to CCR5 on cell lines and primary cells, but not to CD4 or the CD4i monoclonal antibody E51. This owed to differential binding of the gp120s to different CCR5 populations, which exist in varying quantities at the cell surface and are differentially expressed between different cell types. Some, but not all, of these populations are antigenically distinct conformations of the coreceptor. The different binding levels of gp120s also correspond to differences in their capacity to bind CCR5 dimers/oligomers. Mutating the CCR5 dimerization interface changed conformation of the CCR5 homodimers and modulated differentially the binding of distinct gp120s. Env-pseudotyped viruses also use particular CCR5 conformations for entry, which may differ between different viruses and represent a subset of those binding gp120s. In particular, even if gp120s can bind both CCR5 monomers and oligomers, impairment of CCR5 oligomerization improved viral entry, suggesting that HIV-1 prefers monomers for entry. From a functional standpoint, we illustrate that the nature of the CCR5 molecules to which gp120/HIV-1 binds shapes sensitivity to inhibition by CCR5 ligands and cellular tropism. Differences exist in the CCR5 populations between T-cells and macrophages, and this is associated with differential capacity to bind gp120s and to support viral entry. In macrophages, CCR5 structural plasticity is critical for entry of blood-derived R5 isolates, which, in contrast to prototypical M-tropic strains from brain tissues, cannot benefit from enhanced affinity for CD4. Collectively, our results support a role for CCR5 heterogeneity in diversifying the phenotypic properties of HIV-1 isolates and provide new clues for development of CCR5-targeting drugs.


Assuntos
Infecções por HIV/metabolismo , HIV-1/fisiologia , Receptores CCR5/química , Receptores CCR5/metabolismo , Internalização do Vírus , Proteína gp120 do Envelope de HIV/metabolismo , Humanos , Fenótipo , Ligação Proteica
13.
J Appl Clin Med Phys ; 19(6): 88-98, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30216702

RESUMO

The purpose of this work is to assess eight detectors performance for output factor (OF), percent depth dose (PDD), and beam profiles in a 6-MV Clinac stereotactic radiosurgery mode for cone irradiation using Monte Carlo simulation as reference. Cones with diameters comprised between 30 and 4 mm have been studied. The evaluated detectors were ionization chambers: pinpoint and pinpoint 3D, diodes: SRS, P and E, Edge, MicroDiamond and EBT3 radiochromic films. The results showed that pinpoints underestimate OF up to -2.3% for cone diameters ≥10 mm and down to -12% for smaller cones. Both nonshielded (SRS and E) and shielded diodes (P and Edge) overestimate the OF respectively up to 3.3% and 5.2% for cone diameters ≥10 mm and in both cases more than 7% for smaller cones. MicroDiamond slightly overestimates the OF, 3.7% for all the cones and EBT3 film is the closest to Monte Carlo with maximum difference of ±1% whatever the cone size is. For the profiles and the PDD, particularly for the small cones, the size of the detector predominates. All diodes and EBT3 agree with the simulation within ±0.2 mm for beam profiles determination. For PDD curve all the active detectors response agree with simulation up to 1% for all the cones. EBT3 is the more accurate detector for beam profiles and OF determinations of stereotactic cones but it is restrictive to use. Due to respectively inappropriate size of the sensitive volume and composition, pinpoints and diodes do not seem appropriate without OF corrective factors below 10 mm diameter cone. MicroDiamond appears to be the best detector for OF determination regardless all cones. For off-axis measurements, the size of the detector predominates and for PDD all detectors give promising results.


Assuntos
Método de Monte Carlo , Neoplasias/cirurgia , Aceleradores de Partículas/instrumentação , Imagens de Fantasmas , Radiocirurgia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Algoritmos , Simulação por Computador , Humanos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos
14.
J Neurosurg ; 128(1): 3-13, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28298039

RESUMO

OBJECTIVE The goal of this study was to provide insight into the influence of gliomas on gestational outcomes, the impact of pregnancy on gliomas, and the identification of patients at risk. METHODS In this multiinstitutional retrospective study, the authors identified 52 pregnancies in 50 women diagnosed with a glioma. RESULTS For gliomas known prior to pregnancy (n = 24), we found the following: 1) An increase in the quantified imaging growth rates occurred during pregnancy in 87% of cases. 2) Clinical deterioration occurred in 38% of cases, with seizures alone resolving after delivery in 57.2% of cases. 3) Oncological treatments were immediately performed after delivery in 25% of cases. For gliomas diagnosed during pregnancy (n = 28), we demonstrated the following: 1) The tumor was discovered during the second and third trimesters in 29% and 54% of cases, respectively, with seizures being the presenting symptom in 68% of cases. 2) The quantified imaging growth rates did not significantly decrease after delivery and before oncological treatment. 3) Clinical deterioration resolved after delivery in 21.4% of cases. 4) Oncological treatments were immediately performed after delivery in 70% of cases. Gliomas with a high grade of malignancy, negative immunoexpression of alpha-internexin, or positive immunoexpression for p53 were more likely to be associated with tumor progression during pregnancy. Deliveries were all uneventful (cesarean section in 54.5% of cases and vaginal delivery in 45.5%), and the infants were developmentally normal. CONCLUSIONS When a woman harboring a glioma envisions a pregnancy, or when a glioma is discovered in a pregnant patient, the authors suggest informing her and her partner that pregnancy may impact the evolution of the glioma clinically and radiologically. They strongly advise a multidisciplinary approach to management. ■ CLASSIFICATION OF EVIDENCE Type of question: association; study design: case series; evidence: Class IV.


Assuntos
Neoplasias Encefálicas/epidemiologia , Glioma/epidemiologia , Complicações Neoplásicas na Gravidez/epidemiologia , Adulto , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/terapia , Progressão da Doença , Feminino , Seguimentos , Glioma/diagnóstico , Glioma/terapia , Humanos , Gravidez , Complicações Neoplásicas na Gravidez/diagnóstico , Complicações Neoplásicas na Gravidez/terapia , Resultado da Gravidez , Estudos Retrospectivos , Análise de Sobrevida , Adulto Jovem
15.
Nat Commun ; 8(1): 1239, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-29093476

RESUMO

Direct collection of extracellular fluid (ECF) plays a central role in the monitoring of neurological disorders. Current approaches using microdialysis catheters are however drastically limited in term of temporal resolution. Here we show a functional in vivo validation of a droplet collection system included at the tip of a neural probe. The system comprises an advanced droplet formation mechanism which enables the collection of neurochemicals present in the brain ECF at high-temporal resolution. The probe was implanted in a rat brain and could successfully collect fluid samples organized in a train of droplets. A microfabricated target plate compatible with most of the surface-based detection methods was specifically developed for sample analysis. The time-resolved brain-fluid samples are analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The results provide a time evolution picture of the cerebral tissues neurochemical composition for selected elements known for their involvement in neurodegenerative diseases.


Assuntos
Cérebro/química , Líquido Extracelular/química , Microdiálise/métodos , Animais , Encéfalo , Química Encefálica , Cálcio/análise , Feminino , Magnésio/análise , Espectrometria de Massas , Mercúrio/análise , Potássio/análise , Ratos , Ratos Sprague-Dawley , Sódio/análise , Fatores de Tempo
16.
Mol Cell Neurosci ; 85: 1-11, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28811225

RESUMO

The normal cellular role of α-synuclein is of potential importance in understanding diseases in which an aggregated form of the protein has been implicated. A potential loss or change in the normal function of α-synuclein could play a role in the aetiology of diseases such as Parkinson's disease. Recently, it has been suggested that α-synuclein could cause the enzymatic reduction of iron and a cellular increase in Fe(II) levels. Experiments were carried out to determine if such activity could be measured in vivo. Experiments with rats overexpressing human α-synuclein in nigral dopaminergic neurons demonstrated a correlation between α-synuclein expression and ferrireductase activity. Furthermore, studies on tissue from Parkinson's disease patient brains showed a significant decrease in ferrireductase activity, possibly due to deposition of large amounts of inactive protein. Cellular studies suggest that increase ferrireductase activity results in increased levels of dopamine metabolites and increased sensitivity to the toxicity of DOPAL. These findings demonstrate that α-synuclein ferrireductase activity is present in vivo and its alteration may play a role in neuron loss in disease.


Assuntos
Encéfalo/metabolismo , Doença de Parkinson/metabolismo , alfa-Sinucleína/metabolismo , Animais , FMN Redutase/metabolismo , Feminino , Humanos , Masculino , Ratos , Ratos Sprague-Dawley
17.
J Virol Methods ; 236: 184-195, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27451265

RESUMO

The trimeric HIV-1 envelope (Env) glycoproteins gp120 and gp41 mediate virus entry into target cells by engaging CD4 and the coreceptors CCR5 or CXCR4 at the cell surface and driving membrane fusion. Receptor/gp120 interactions regulate the virus life cycle, HIV infection transmission and pathogenesis. Env is also the target of neutralizing antibodies. Efforts have thus been made to produce soluble HIV-1 glycoproteins to develop vaccines and study the role and mechanisms of HIV/receptor interactions. However, production and purification of Env glycoproteins and their functional assessment has to cope with multiple obstacles. These include difficulties in amplifying and cloning env sequences and setting up receptor binding assays that are suitable for studies on large collections of glycoproteins, flexible enough to adapt to Env and receptor structural heterogeneities, and allow recapitulating the receptor binding properties of virion-associated Env trimers. Here we identify these difficulties and present protocols to produce primary gp120 and determination of their binding properties to receptors. The receptor binding assays confirmed that the produced glycoproteins are competent for binding CD4 and undergo proper CD4-induced conformational changes required for interaction with CCR5. These assays may help elucidate the role of gp120/receptor interactions in the pathophysiology of HIV infection and develop HIV-1 entry inhibitors.


Assuntos
Clonagem Molecular , Expressão Gênica , Biologia Molecular/métodos , Proteínas Recombinantes/isolamento & purificação , Produtos do Gene env do Vírus da Imunodeficiência Humana/isolamento & purificação , Guias como Assunto , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismo
18.
Retrovirology ; 13(1): 50, 2016 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-27473399

RESUMO

BACKGROUND: Covariation is an essential process that leads to coevolution of parts of proteins and genomes. In organisms subject to strong selective pressure, coevolution is central to keep the balance between the opposite requirements of antigenic variation and retention of functionality. Being the viral component most exposed to the external environment, the HIV-1 glycoprotein gp120 constitutes the main target of the immune response. Accordingly its more external portions are characterised by extensive sequence heterogeneity fostering constant antigenic variation. RESULTS: We report that a single polymorphism, present at the level of the viral population in the conserved internal region C2, was sufficient to totally abolish Env functionality when introduced in an exogenous genetic context. The prominent defect of the non-functional protein is a block occurring after recognition of the co-receptor CCR5, likely due to an interference with the subsequent conformational changes that lead to membrane fusion. We also report that the presence of compensatory polymorphisms at the level of the external and hypervariable region V3 fully restored the functionality of the protein. The functional revertant presents different antigenic profiles and sensitivity to the entry inhibitor TAK 779. CONCLUSIONS: Our data suggest that variable regions, besides harbouring intrinsic extensive antigenic diversity, can also contribute to sequence diversification in more structurally constrained parts of the gp120 by buffering the deleterious effect of polymorphisms, further increasing the genetic flexibility of the protein and the antigenic repertoire of the viral population.


Assuntos
Proteína gp120 do Envelope de HIV/genética , HIV-1/genética , Polimorfismo Genético , Amidas/farmacologia , Variação Antigênica , Antígenos CD4/metabolismo , Evolução Molecular , Variação Genética , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Inibidores da Fusão de HIV/farmacologia , HIV-1/imunologia , HIV-1/fisiologia , Humanos , Estabilidade Proteica , Compostos de Amônio Quaternário/farmacologia , Receptores CCR5/metabolismo , Alinhamento de Sequência , Internalização do Vírus
19.
Neuro Oncol ; 18(9): 1297-303, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26951382

RESUMO

BACKGROUND: Treatment of relapsed/refractory (R/R) primary CNS lymphoma (PCNSL) is poorly defined, because randomized trials and large studies are lacking. The aim of this study was to analyze the characteristics, management, and outcome of R/R PCNSL patients after first-line therapy in a nationwide cohort. METHODS: We analyzed R/R PCNSL patients following first-line treatment who had been prospectively registered in the database of the French network for oculocerebral lymphoma (LOC) between 2011 and 2014. RESULTS: Among 563 PCNSL patients treated with first-line therapy, we identified 256 with relapsed (n = 93, 16.5%) or refractory (n = 163, 29.0%) disease. Patients who were asymptomatic at relapse/progression (25.5%), mostly diagnosed on routine follow-up neuroimaging, tended to have a better outcome. Patients who received salvage therapy followed by consolidation (mostly intensive chemotherapy plus autologous hematopoietic stem cell transplantation [ICT + AHSCT]) experienced prolonged survival compared with those who did not receive salvage or consolidation therapy. Independent prognostic factors at first relapse/progression were: KPS ≥ 70 vs KPS < 70), sensitivity to first-line therapy (relapsed vs refractory disease), duration of first remission (progression-free survival [PFS] ≥1 y vs <1 y), and management at relapse/progression (palliative care vs salvage therapy). Patients who relapsed early after first-line therapy (ie, PFS < 1 y) had a poor outcome, comparable to that of refractory patients. Conversely, patients experiencing late relapses (PFS ≥ 1 y) and/or undergoing consolidation with ICT + AHSCT experienced prolonged survival. CONCLUSIONS: About a third of PCNSL patients are primary refractory to first line treatment. We identified several independent prognostic factors that can guide the management of R/R PCNSL patients.


Assuntos
Neoplasias do Sistema Nervoso Central/terapia , Resistencia a Medicamentos Antineoplásicos , Linfoma não Hodgkin/terapia , Recidiva Local de Neoplasia/terapia , Terapia de Salvação , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Nervoso Central/patologia , Terapia Combinada , Progressão da Doença , Feminino , Transplante de Células-Tronco Hematopoéticas , Humanos , Linfoma não Hodgkin/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Prognóstico , Estudos Prospectivos , Taxa de Sobrevida , Transplante Autólogo
20.
Neurology ; 85(15): 1325-31, 2015 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-26385879

RESUMO

OBJECTIVES: We aimed to study the potential clinical relevance of 9p allelic loss, with or without copy number variation, in 1p/19q codeleted anaplastic oligodendroglial tumors (AOTs). METHODS: This study enrolled 216 patients with 1p/19q codeleted AOT. The prognostic value of 9p allelic loss was investigated using a French nation-wide prospective registry, POLA (prise en charge des tumeurs oligodendrogliales anaplasiques) and high-density single nucleotide polymorphism arrays. We validated our results using the Repository of Molecular Brain Neoplasia Data (REMBRANDT) dataset. RESULTS: The minimal common region of allelic loss in chromosome arm 9p was 9p21.3. Allelic loss of 9p21.3, detected in 41.7% of tumors, was associated with shorter progression-free and overall survival rates in univariate (p = 0.008 and p < 0.001, respectively) and multivariate analyses (p = 0.009 and p = 0.009, respectively). This finding was validated in the REMBRANDT dataset in univariate and multivariate analysis (p = 0.01 and p = 0.01, respectively). CONCLUSION: Our study highlights a novel potential prognostic biomarker in 1p/19q codeleted AOT. Further prospective studies are warranted to investigate our finding.


Assuntos
Neoplasias Encefálicas/genética , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 9/genética , Variações do Número de Cópias de DNA/genética , Glioma/diagnóstico , Glioma/epidemiologia , Perda de Heterozigosidade/genética , Adulto , Idoso , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/patologia , Deleção Cromossômica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos
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