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1.
Brain ; 147(5): 1644-1652, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38428032

RESUMO

The pathological misfolding and aggregation of soluble α-synuclein into toxic oligomers and insoluble amyloid fibrils causes Parkinson's disease, a progressive age-related neurodegenerative disease for which there is no cure. HET-s is a soluble fungal protein that can form assembled amyloid fibrils in its prion state. We engineered HET-s(218-298) to form four different fibrillar vaccine candidates, each displaying a specific conformational epitope present on the surface of α-synuclein fibrils. Vaccination with these four vaccine candidates prolonged the survival of immunized TgM83+/- mice challenged with α-synuclein fibrils by 8% when injected into the brain to model brain-first Parkinson's disease or by 21% and 22% when injected into the peritoneum or gut wall, respectively, to model body-first Parkinson's disease. Antibodies from fully immunized mice recognized α-synuclein fibrils and brain homogenates from patients with Parkinson's disease, dementia with Lewy bodies and multiple system atrophy. Conformation-specific vaccines that mimic epitopes present only on the surface of pathological fibrils but not on soluble monomers, hold great promise for protection against Parkinson's disease, related synucleinopathies and other amyloidogenic protein misfolding disorders.


Assuntos
Camundongos Transgênicos , Doença de Parkinson , alfa-Sinucleína , Animais , Doença de Parkinson/imunologia , Doença de Parkinson/patologia , Camundongos , alfa-Sinucleína/imunologia , alfa-Sinucleína/metabolismo , Humanos , Amiloide/imunologia , Amiloide/metabolismo , Vacinação , Proteínas Fúngicas/imunologia , Encéfalo/patologia , Encéfalo/metabolismo , Encéfalo/imunologia , Feminino , Camundongos Endogâmicos C57BL
2.
Appl Environ Microbiol ; 90(10): e0115024, 2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39365048

RESUMO

The severe acute respiratory syndrome coronavirus 2 pandemic has raised public awareness about the importance of hygiene, leading to an increased demand for antimicrobial surfaces to minimize microbial contamination on high-touch surfaces. This is particularly relevant in public and private transportation settings, where surfaces frequently touched by individuals pose a significant, yet preventable, risk of infection transmission. Typically, the antimicrobial activity of surfaces is tested using test methods of the International Standards Organization, American Society for Testing and Materials, or Japanese Industrial Standards, which involve complete submersion in liquid, elevated temperature (37°C), and prolonged (24 h) contact periods. However, these conditions do not accurately represent real-world scenarios where surfaces are exposed to air. In this study, we propose a modified test method designed to better reflect real-life conditions in the intended end-use setting. The modifications included using deionized water instead of nutrient broth while preparing bacterial inoculum, applying a small test inoculum to the surface and allowing it to dry, maintaining ambient temperature and relative humidity throughout the contact period, and reducing the contact period to 4 h. With this modified approach, the antimicrobial activity of 20 samples was reassessed. This screening revealed that out of 20 samples, only 2 samples were effective against all species, while 8 samples demonstrated partial effectiveness against selected species, and 10 samples showed no significant effect. These findings highlight the inadequacy of the current test standard and emphasize the urgent necessity for revised and adapted testing method to ensure a reliable and accurate evaluation.IMPORTANCEThe recent severe acute respiratory syndrome coronavirus 2 pandemic has sparked increased demand for antimicrobial surfaces to mitigate the risk of fomites-transmitted infection in both indoors and confined spaces. Commonly, the antimicrobial activity of these surfaces is assessed using test standards established by national standards bodies, which do not distinguish between different application scenarios. While these test standards are suitable for surfaces intended for submerged application, they are inappropriate for antimicrobial surfaces designed for dry surface exposure. The usage of these standards can lead to an overestimation of antimicrobial efficacy. Thus, this study introduces a modified dry exposure test method aimed at better reflecting real-life conditions in the intended end-use setting. Our results revealed the subpar antimicrobial performance of numerous samples, highlighting the necessity to revise and tailor the universal test standard to real-world scenarios in order to ensure a reliable and accurate evaluation.


Assuntos
COVID-19 , COVID-19/prevenção & controle , Humanos , SARS-CoV-2/efeitos dos fármacos , Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Propriedades de Superfície
3.
Nature ; 563(7729): 121-125, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30333624

RESUMO

Many evolutionarily distant pathogenic organisms have evolved similar survival strategies to evade the immune responses of their hosts. These include antigenic variation, through which an infecting organism prevents clearance by periodically altering the identity of proteins that are visible to the immune system of the host1. Antigenic variation requires large reservoirs of immunologically diverse antigen genes, which are often generated through homologous recombination, as well as mechanisms to ensure the expression of one or very few antigens at any given time. Both homologous recombination and gene expression are affected by three-dimensional genome architecture and local DNA accessibility2,3. Factors that link three-dimensional genome architecture, local chromatin conformation and antigenic variation have, to our knowledge, not yet been identified in any organism. One of the major obstacles to studying the role of genome architecture in antigenic variation has been the highly repetitive nature and heterozygosity of antigen-gene arrays, which has precluded complete genome assembly in many pathogens. Here we report the de novo haplotype-specific assembly and scaffolding of the long antigen-gene arrays of the model protozoan parasite Trypanosoma brucei, using long-read sequencing technology and conserved features of chromosome folding4. Genome-wide chromosome conformation capture (Hi-C) reveals a distinct partitioning of the genome, with antigen-encoding subtelomeric regions that are folded into distinct, highly compact compartments. In addition, we performed a range of analyses-Hi-C, fluorescence in situ hybridization, assays for transposase-accessible chromatin using sequencing and single-cell RNA sequencing-that showed that deletion of the histone variants H3.V and H4.V increases antigen-gene clustering, DNA accessibility across sites of antigen expression and switching of the expressed antigen isoform, via homologous recombination. Our analyses identify histone variants as a molecular link between global genome architecture, local chromatin conformation and antigenic variation.


Assuntos
Variação Antigênica/genética , Cromatina/genética , Cromatina/metabolismo , DNA de Protozoário/metabolismo , Genoma/genética , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/imunologia , DNA de Protozoário/genética , Haplótipos/genética , Histonas/deficiência , Histonas/genética , Família Multigênica/genética , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Glicoproteínas Variantes de Superfície de Trypanosoma/biossíntese , Glicoproteínas Variantes de Superfície de Trypanosoma/genética
4.
Curr Cardiol Rep ; 25(9): 1053-1064, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37498450

RESUMO

PURPOSE OF REVIEW: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in women in the United States of America. Despite this, women are underdiagnosed, less often receive preventive care, and are undertreated for CVD compared to men. There has been an increase in sex-specific risk factors and treatments over the past decade; however, sex-specific recommendations have not been included in the guidelines. We aim to highlight recent evidence behind the differential effect of traditional risk factors and underscore sex-specific risk factors with an intention to promote awareness, improve risk stratification, and early implementation of appropriate preventive therapies in women. RECENT FINDINGS: Women are prescribed fewer antihypertensives and lipid-lowering agents and receive less cardiovascular care as compared to men. Additionally, pregnancy complications have been associated with increased cardiovascular mortality later in life. Findings from the ARIC study suggest that there is a perception of lower risk of cardiovascular disease in women. The SWEDEHEART study which investigated sex differences in treatment, noted a lower prescription of guideline-directed therapy in women. Women are less likely to be prescribed statin medications by their providers in both primary and secondary prevention as they are considered lower risk than men, while also being more likely to decline and discontinue treatment. A woman's abnormal response to pregnancy may serve as her first physiological stress test which can have implications on her future cardiovascular health. This was supported by the CHAMPs study noting a higher premature cardiovascular risk after maternal complications. Adverse pregnancy outcomes have been associated with a 1.5-4.0 fold increase in future cardiovascular events in multiple studies. In this review, we highlight the differences in traditional risk factors and their impact on women. Furthermore, we address the sex-specific risk factors and pregnancy-associated complications that increase the risk of CVD in women. Adherence to GDMT may have implications on overall mortality in women. An effort to improve early recognition of CVD risk with implementation of aggressive risk factor control and lifestyle modification should be emphasized. Future studies should specifically report on differences in outcomes between males and females. Increased awareness and knowledge on sex-specific risks and prevention are likely to lower the prevalence and improve outcomes of CVD in women.


Assuntos
Doenças Cardiovasculares , Gravidez , Feminino , Humanos , Masculino , Estados Unidos/epidemiologia , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/prevenção & controle , Doenças Cardiovasculares/epidemiologia , Fatores de Risco , Fatores de Risco de Doenças Cardíacas , Anti-Hipertensivos/uso terapêutico , Hipolipemiantes
5.
Psychopathology ; 52(5): 283-293, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31665738

RESUMO

INTRODUCTION: Facial expressions and vocal intonation are key signals in the communication of emotions. Individuals with posttraumatic stress disorder (PTSD) are known to show an impaired perception of facial emotions. So far, research on multimodal emotional stimuli or the priming effects on emotion processing has been absent in PTSD. Therefore, we conducted a study to investigate the influence of vocal priming on facial emotion processing and classification in PTSD using electroencephalography. METHODS: Twenty-one women with PTSD compared to 28 healthy women were asked to classify emotion-morphed faces with predominantly angry, ambiguous, or predominantly happy expressions primed by either an angry or a happy voice. Responses and reaction times as well as the N170, a component reflecting configural face processing, were analyzed. RESULTS: Patients with PTSD were slower in classifying emotional faces that were primed by either an angry or happy voice compared to the healthy controls (HCs; η2 = 0.14). Additionally, patients with PTSD were faster in classifying facial expressions after angry compared to happy vocal primes (η2 = 0.14). HCs did not show this effect. Correlation analyses revealed positive associations between emotion (dys-)regulation and reaction times in patients with PTSD but not in HCs (r = 0.64-0.76). Furthermore, patients with PTSD showed greater N170 amplitudes for predominantly angry and ambiguous faces than HCs (η2 = 0.07). CONCLUSION: Data suggest that patients with PTSD experience more difficulties when processing complex social stimuli than HCs. The altered processing of complex social-emotional signals could amplify PTSD symptoms, thus qualifying as an explicit therapy target.


Assuntos
Emoções/fisiologia , Expressão Facial , Transtornos de Estresse Pós-Traumáticos/psicologia , Voz/fisiologia , Adulto , Feminino , Humanos
6.
J Antimicrob Chemother ; 73(10): 2762-2769, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982453

RESUMO

Objectives: In the context of cystic fibrosis, Pseudomonas aeruginosa biofilms often develop in the vicinity of airway mucus, which acts as a protective physical barrier to inhaled matter. However, mucus can also adsorb small drug molecules administered as aerosols, including antibiotics, thereby reducing their bioavailability. The efficacy of antibiotics is typically assessed by determining the MIC using in vitro assays. This widespread technique, however, does not consider either bacterial biofilm formation or the influence of mucus, both of which may act as diffusion barriers, potentially limiting antibiotic efficacy. Methods: We grew P. aeruginosa biofilms in the presence or absence of human tracheal mucus and tested their susceptibility to tobramycin and colistin. Results: A significant reduction of tobramycin efficacy was observed when P. aeruginosa biofilms were grown in the presence of mucus compared with those grown in the absence of mucus. Diffusion of tobramycin through mucus was reduced; however, this reduction was more pronounced in biofilm/mucus mixtures, suggesting that biofilms in the presence of mucus respond differently to antibiotic treatment. In contrast, the influence of mucus on colistin efficacy was almost negligible and no differences in mucus permeability were observed. Conclusions: These findings underline the important role of mucus in the efficacy of anti-infective drugs.


Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Colistina/farmacologia , Muco/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Tobramicina/farmacologia , Biofilmes/crescimento & desenvolvimento , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/crescimento & desenvolvimento , Traqueia/metabolismo
7.
Biomacromolecules ; 19(2): 374-385, 2018 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-29286657

RESUMO

Nanomaterials are interesting candidates for applications in medicine as drug delivery or diagnostic agents. For safe application, they have to be evaluated in in vitro and in vivo models to finally be translated to human clinical trials. However, often those transfer processes fail, and it is not completely understood whether in vitro models leading to these animal models can reliably be compared to the situation in humans. In particular, the interaction of nanomaterials with components from different blood plasma sources is difficult to compare, and the outcomes of those interactions with respect to body distribution and cell uptake are unclear. Therefore, we investigated the interactions of differently functionalized polymeric and inorganic nanoparticles with human, mouse, rabbit, and sheep plasma. The focus was put on the determination of aggregation events of the nanoparticles occurring in concentrated plasma and the correlation with the respectively formed protein coronas. Both the stability in plasma as well as the types of adsorbed proteins were found to strongly depend on the plasma source. Thus, we suggest evaluating the potential use of nanocarriers always in the plasma source of the chosen animal model for in vitro studies as well as in human plasma to pin down differences and eventually enable transfer into clinical trials in humans.


Assuntos
Nanopartículas/efeitos adversos , Coroa de Proteína , Animais , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Camundongos , Nanopartículas/química , Plasma/efeitos dos fármacos , Poliestirenos/efeitos adversos , Poliestirenos/química , Coelhos , Ovinos , Especificidade da Espécie
8.
Eur Arch Psychiatry Clin Neurosci ; 268(4): 429-439, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28956145

RESUMO

According to longitudinal studies, most individuals with borderline personality disorder (BPD) achieve remission. Since BPD is characterized by disturbed emotion recognition, this study investigated behavioral and electrophysiological correlates of facial emotion classification and processing in remitted BPD. 32 women with remitted BPD (rBPD), 32 women with current BPD (cBPD), and 28 healthy women (HC) participated in an emotion classification paradigm comprising blends of angry and happy faces while behavioral and electroencephalographic (event-related potentials) data were recorded. rBPD demonstrated a convergence in behavior towards HC in terms of responses and reaction times. They evaluated maximally ambiguous faces more positively and exhibited faster reaction times when classifying predominantly happy faces compared to cBPD. Group × facial emotion interaction effects were found in early electrophysiological processes with post hoc tests indicating differences between rBPD and cBPD but not between rBPD and HC. However, BPD-like impairments were still found in rBPD in later processing (P300). Our results suggest a reduction in negativity bias in rBPD on the behavioral level and a normalization of earlier stages of facial processing on the neural level, while alterations in later, more cognitive processing do not remit. Early processing may be more state-like, while later impairments may be more trait-like. Further research may need to focus on these stable components.


Assuntos
Transtorno da Personalidade Borderline/fisiopatologia , Eletroencefalografia , Emoções/fisiologia , Potenciais Evocados/fisiologia , Expressão Facial , Adulto , Transtorno da Personalidade Borderline/psicologia , Mapeamento Encefálico , Emoções/classificação , Reconhecimento Facial , Feminino , Humanos , Estudos Longitudinais , Estimulação Luminosa , Psicometria , Tempo de Reação/fisiologia , Adulto Jovem
9.
J Neural Transm (Vienna) ; 124(11): 1473-1488, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-28864837

RESUMO

Functional near-infrared spectroscopy (fNIRS) and vagus somatosensory evoked potentials (VSEP) show deviant patterns in subjects with Alzheimer's disease (AD) compared to healthy controls. We now aimed at testing the predictive value of these methods in the early diagnosis of AD. The Vogel study is a prospective, observational, long-term follow-up study with three time points of investigation within 6 years. Residents of the city of Würzburg born between 1936 and 1941 were recruited. Every participant underwent physical, psychiatric, and laboratory examinations, and performed an intense neuropsychological testing as well as VSEP and NIRS according to the published procedures. 604 subjects were included. Mean age of the participants was 73.9 ± 1.55 years. The most frequent pathological physical and laboratory examination results were observed for blood pressure (62%), body weight (54%), HbA1c (16%), cholesterol (42%), and homocysteine (69%). Comprehensive analysis of cognitive testing showed mild cognitive impairment (MCI) in 12.3% of the patients. Concurrent major depression was found in 6.6% of the patients. We observed a high rate of MCI and somatic comorbidity in our cohort. The high rate of vascular risk factors and depressive symptoms, all of which are known risk factors of AD, is consistent with the notion that there are multiple options to prevent or postpone the onset of AD in a geriatric population like the one of the Vogel studies.


Assuntos
Doença de Alzheimer/diagnóstico , Doença de Alzheimer/fisiopatologia , Potenciais Somatossensoriais Evocados/fisiologia , Hemoglobinas Glicadas/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho , Nervo Vago/fisiopatologia , Idoso , Diagnóstico Precoce , Feminino , Alemanha , Humanos , Estudos Longitudinais , Masculino , Transtornos do Humor/etiologia , Testes Neuropsicológicos , Avaliação de Resultados em Cuidados de Saúde , Índice de Gravidade de Doença , Estimulação Elétrica Nervosa Transcutânea
11.
J Am Chem Soc ; 138(7): 2244-51, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26878670

RESUMO

Tandem ring-opening/ring-closing metathesis (RO/RCM) results in extremely fast living polymerization; however, according to previous reports, only monomers containing certain combinations of cycloalkenes, terminal alkynes, and nitrogen linkers successfully underwent tandem polymerization. After examining the polymerization pathways, we proposed that the relatively slow intramolecular cyclization might lead to competing side reactions such as intermolecular cross metathesis reactions to form inactive propagating species. Thus, we developed two strategies to enhance tandem polymerization efficiency. First, we modified monomer structures to accelerate tandem RO/RCM cyclization by enhancing the Thorpe-Ingold effect. This strategy increased the polymerization rate and suppressed the chain transfer reaction to achieve controlled polymerization, even for challenging syntheses of dendronized polymers. Alternatively, reducing the reaction concentration facilitated tandem polymerization, suggesting that the slow tandem RO/RCM cyclization step was the main reason for the previous failure. To broaden the monomer scope, we used monomers containing internal alkynes and observed that two different polymer units with different ring sizes were produced as a result of nonselective α-addition and ß-addition on the internal alkynes. Thorough experiments with various monomers with internal alkynes suggested that steric and electronic effects of the alkyne substituents influenced alkyne addition selectivity and the polymerization reactivity. Further polymerization kinetics studies revealed that the rate-determining step of monomers containing certain internal alkynes was the six-membered cyclization step via ß-addition, whereas that for other monomers was the conventional intermolecular propagation step, as observed in other chain-growth polymerizations. This conclusion agrees well with all those polymerization results and thus validates our strategies.

12.
Mol Pharm ; 13(11): 3636-3647, 2016 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-27700112

RESUMO

Herein we report on a liposomal system for siRNA delivery consisting of cholesterol (Chol), distearoylphosphatidylcholine (DSPC), and surfactant TF (1-hydroxy-50-amino-3,4,7,10,13,16,19,22-octaoxa-37,41,45-triaza-pentacontane), a novel spermine derivative (HO-EG8-C12-spermine) which has shown improved siRNA delivery to cells in vitro and in vivo. Predominantly single-walled liposomes with reproducible sizes and moderately broad size distributions were generated with an automated extrusion device. The liposomes remained stable when prepared in the presence of siRNA at N/P ratios of 17-34. However, when mixed with human serum in equal volumes, larger aggregates in the size range of several hundred nanometers were observed by dynamic light scattering. These larger aggregates could potentially limit prolonged in vivo applications. Aggregate formation could be reduced by the addition of a cholesterol-hyperbranched polyglycerol surfactant (hbPG) that sterically shields the liposomal surface against serum induced aggregation. In vitro experiments with murine macrophages utilizing macrophage-specific anti-CD68 siRNA loaded liposomes showed potent and sequence specific reduction of CD68 transcript levels without cytotoxicity. Experiments in mice using intravenous application of CW800 NHS ester labeled liposomes, near-infrared in vivo imaging, and fluorescent assisted cell sorting of inflammatory cells demonstrated an almost quantitative accumulation of these liposomes, with and without hbPG, in the liver and a specific knockdown of CD68 mRNA of up to 70% in liver resident macrophages. It was found that aggregate formation of TF liposomes in serum does not significantly affect in vivo siRNA delivery to these central inflammatory cells of the liver.


Assuntos
Lipossomos/química , Fígado/citologia , Macrófagos/metabolismo , RNA Interferente Pequeno/administração & dosagem , Espermina/química , Tensoativos/química , Animais , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Células Cultivadas , Colesterol/química , Portadores de Fármacos/química , Citometria de Fluxo , Camundongos , Modelos Teóricos , Tamanho da Partícula , Fosfatidilcolinas/química , RNA Interferente Pequeno/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa
13.
J Neural Transm (Vienna) ; 123(9): 1107-18, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27311838

RESUMO

Traumatic experiences have severe impact on the autonomous nervous system. Heart rate variability (HRV) is a reliable psychophysiological marker for the autonomous nervous system functioning. Reduced vagally mediated HRV has been found in patients with post-traumatic stress disorder (PTSD) and, in some studies, in patients with borderline personality disorder (BPD). In this study, we compared HRV parameters of patients with PTSD, current BPD, and BPD in remission with healthy volunteers in a 5 min resting-state electrocardiogram recording. 91 unmedicated female participants took part in the study (18 with PTSD, 27 with the current BPD, 23 with BPD in remission, and 23 healthy volunteers). We found significant group differences in both time-domain and frequency-domain (total power, low-frequency and high-frequency power) HRV parameters. Root mean square of the successive differences (RMSSD) was lowest in patients with PTSD (M = 48.6 ms, SD = 23.5 ms) followed by patients with BPD in remission (M = 57.7 ms, SD = 31.5 ms) and patients with the current BPD (M = 71.1 ms, SD = 44.5 ms), while the highest RMSSD was found in healthy volunteers (M = 84.1 ms, SD = 41.7 ms). Variance of HRV was higher in patients with BPD than in patients with PTSD. In addition, RMSSD was significantly negatively correlated with self-reported early life maltreatment assessed with the Childhood Trauma Questionnaire. Our findings point out a complex interaction between traumatic experiences, the functioning of the autonomic nervous system, and psychopathology. Alterations in HRV might be related to early life maltreatment or associated psychological factors rather than diagnostic entities.


Assuntos
Transtorno da Personalidade Borderline/fisiopatologia , Transtorno da Personalidade Borderline/psicologia , Maus-Tratos Infantis/psicologia , Frequência Cardíaca/fisiologia , Abuso Físico/psicologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Adulto , Criança , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Estatística como Assunto , Adulto Jovem
14.
Nucleic Acids Res ; 42(5): 3164-76, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24353315

RESUMO

Monoallelic expression within a gene family is found in pathogens exhibiting antigenic variation and in mammalian olfactory neurons. Trypanosoma brucei, a lethal parasite living in the human bloodstream, expresses variant surface glycoprotein (VSG) from 1 of 15 bloodstream expression sites (BESs) by virtue of a multifunctional RNA polymerase I. The active BES is transcribed in an extranucleolar compartment termed the expression site body (ESB), whereas silent BESs, located elsewhere within the nucleus, are repressed epigenetically. The regulatory mechanisms, however, are poorly understood. Here we show that two essential subunits of the basal class I transcription factor A (CITFA) predominantly occupied the promoter of the active BES relative to that of a silent BES, a phenotype that was maintained after switching BESs in situ. In these experiments, high promoter occupancy of CITFA was coupled to high levels of both promoter-proximal RNA abundance and RNA polymerase I occupancy. Accordingly, fluorescently tagged CITFA-7 was concentrated in the nucleolus and the ESB. Because a ChIP-seq analysis found that along the entire BES, CITFA-7 is specifically enriched only at the promoter, our data strongly indicate that monoallelic BES transcription is activated by a mechanism that functions at the level of transcription initiation.


Assuntos
Regiões Promotoras Genéticas , Proteínas de Protozoários/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional , Trypanosoma brucei brucei/genética , Glicoproteínas Variantes de Superfície de Trypanosoma/genética , Nucléolo Celular/química , Inativação Gênica , Genes de RNAr , Proteínas de Protozoários/análise , Fatores de Transcrição/análise , Iniciação da Transcrição Genética
15.
J Bacteriol ; 197(8): 1394-407, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25666133

RESUMO

UNLABELLED: α-Glucan phosphorylases contribute to degradation of glycogen and maltodextrins formed in the course of maltose metabolism in bacteria. Accordingly, bacterial α-glucan phosphorylases are classified as either glycogen or maltodextrin phosphorylase, GlgP or MalP, respectively. GlgP and MalP enzymes follow the same catalytic mechanism, and thus their substrate spectra overlap; however, they differ in their regulation: GlgP genes are constitutively expressed and the enzymes are controlled on the activity level, whereas expression of MalP genes are transcriptionally controlled in response to the carbon source used for cultivation. We characterize here the modes of control of the α-glucan phosphorylase MalP of the Gram-positive Corynebacterium glutamicum. In accordance to the proposed function of the malP gene product as MalP, we found transcription of malP to be regulated in response to the carbon source. Moreover, malP transcription is shown to depend on the growth phase and to occur independently of the cell glycogen content. Surprisingly, we also found MalP activity to be tightly regulated competitively by the presence of ADP-glucose, an intermediate of glycogen synthesis. Since the latter is considered a typical feature of GlgPs, we propose that C. glutamicum MalP acts as both maltodextrin and glycogen phosphorylase and, based on these findings, we question the current system for classification of bacterial α-glucan phosphorylases. IMPORTANCE: Bacterial α-glucan phosphorylases have been classified conferring to their purpose as either glycogen or maltodextrin phosphorylases. We found transcription of malP in C. glutamicum to be regulated in response to the carbon source, which is recognized as typical for maltodextrin phosphorylases. Surprisingly, we also found MalP activity to be tightly regulated competitively by the presence of ADP-glucose, an intermediate of glycogen synthesis. The latter is considered a typical feature of GlgPs. These findings, taken together, suggest that C. glutamicum MalP is the first α-glucan phosphorylase that does not fit into the current system for classification of bacterial α-glucan phosphorylases and exemplifies the complex mechanisms underlying the control of glycogen content and maltose metabolism in this model organism.


Assuntos
Adenosina Difosfato Glucose/metabolismo , Corynebacterium glutamicum/enzimologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Regulação Enzimológica da Expressão Gênica/fisiologia , Fosforilases/metabolismo , Transcrição Gênica/fisiologia , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/metabolismo , Fosforilases/genética
16.
Biochem Biophys Res Commun ; 468(3): 411-8, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26315266

RESUMO

In the last decades, the development and design of drug delivery systems have attracted great attention. Especially siRNA carriers have been of special interest since discovered as suitable tool for gene silencing. Self-assembled structures consisting of amphiphilic molecules are the most investigated carriers with regards to siRNA delivery. Liposomes as drug vehicles already found their way into clinical use, as they are highly biocompatible and their colloidal stability and circulation time in blood can be significantly enhanced by PEGylation. Fully synthetic polymersomes inspired by these natural structures provide enhanced stability and offer a wide range of modification-possibilities. Therefore, their design as carrier vehicles has become of great interest. This mini-review highlights the possibilities of using polymeric vesicles for potential drug delivery and gives a brief overview of their potential regarding fine-tuning towards targeted delivery or triggered drug release.


Assuntos
Produtos Biológicos/química , Preparações de Ação Retardada/química , Lipossomos/química , Nanocápsulas/química , Polímeros/química , Nanocápsulas/ultraestrutura
18.
Langmuir ; 30(49): 14954-62, 2014 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-25469945

RESUMO

To overcome the limited functionality of "stealth" lipids based on linear poly(ethylene glycol) (PEG) chains, hyperbranched polyether-based lipids that bear multiple hydroxyl groups for further chemical modification may be a suitable replacement. This study focuses on the development and characterization of "stealth" liposomes modified with a novel hyperbranched polyglycerol lipid (cholesterol-PEG30-hbPG23). An emphasis was placed on the stability of these liposomes in comparison to those containing a linear PEG derivative (cholesterol-PEG44) directly in human blood serum, characterized via dynamic light scattering (DLS). Polymer lipid contents were varied between 0 and 30 mol %, resulting in liposomes with sizes between 150 and 80 nm in radius, depending on the composition. DLS analysis showed no aggregation inducing interactions between serum components and liposomes containing 10-30 mol % of the hyperbranched lipid. In contrast, liposomes functionalized with comparable amounts of linear PEG exhibited aggregate formation in the size range of 170-330 nm under similar conditions. In addition to DLS, cryo-transmission electron microscopy (TEM) was employed for all liposome samples to prove the formation of unilamellar vesicles. These results demonstrate the outstanding potential of the introduction of hyperbranched polyglycerol into liposomes to stabilize the assemblies against aggregation while providing additional functionalization sites.


Assuntos
Análise Química do Sangue/métodos , Glicerol/química , Lipídeos/química , Lipossomos/sangue , Polímeros/química , Colesterol/química , Humanos , Lipossomos/química , Microscopia Eletrônica de Transmissão , Modelos Biológicos , Estrutura Molecular
19.
Neuropharmacology ; 251: 109930, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38537867

RESUMO

OBJECTIVE: This study extended a classic self-referential learning paradigm by investigating the effects of intranasally-administered oxytocin in high and low socially anxious participants during social learning, as a function of social anxiety levels and sex. METHODS: In a randomized double-blinded design, 160 participants were either given intranasal oxytocin (24 I.U.) or placebo. Subsequently, while lying in an MR scanner, participants were shown neutral faces that were paired with positively, neutrally, or negatively valenced self-referential sentences, during which we measured self-reported arousal and sympathy of the facial stimuli, pupil dilation, and changes in the brain-oxygen-level dependent signal. Four-factor mixed analyses of variance with the between-subjects factors group (high socially anxious vs. low socially anxious), substance (oxytocin vs. placebo), and sex (male vs. female) and the within-subjects factor sentence valence (positive vs. neutral vs. negative) were conducted for each measure, respectively. RESULTS: Administration of intranasal oxytocin yielded an increase in sympathy ratings in high socially anxious compared to low socially anxious individuals and decreased arousal ratings for positively-conditioned faces in low socially anxious participants. As an objective physiological measure of arousal, pupil dilation mirrored the behavioral results. Oxytocin effects on neural activation in the insula interacted with anxiety levels and sex: low socially anxious individuals yielded lower activation under oxytocin than placebo; the converse was observed in high socially anxious individuals. This interaction also differed between sexes, as men yielded higher activation levels than women. These findings were more prominent for positively- and negatively-conditioned faces. Within the amygdala, high socially anxious men yielded higher activation than high socially anxious women in the left hemisphere, and low socially anxious men yielded higher activation than low socially anxious women from positively- and negatively-conditioned faces, though no influence of oxytocin was detected. CONCLUSION: These results suggest oxytocin-induced behavioral, physiological, and neural changes as a function of social learning in socially low and high anxious individuals. These findings challenge the amygdalocentric view of the role of emotions in social learning, instead contributing to the growing body of findings implicating the insula therein, revealing an interaction between oxytocin, sex, and emotional valence. Such discoveries raise an interesting set of questions regarding the computational goals of regions such as the insula in emotional learning and how neural activity can play a diagnostic or prognostic role in social anxiety, potentially leading to new treatment opportunities that may combine oxytocin and neurofeedback differentially for men and women.


Assuntos
Ocitocina , Aprendizado Social , Humanos , Masculino , Feminino , Ocitocina/farmacologia , Ansiedade , Emoções/fisiologia , Encéfalo/diagnóstico por imagem , Administração Intranasal , Imageamento por Ressonância Magnética , Método Duplo-Cego
20.
Health Econ Rev ; 14(1): 27, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38607501

RESUMO

BACKGROUND: Based on the legal framework laid down in section 130b (9) of Book V of the German Social Code, various criteria are relevant for the negotiated price for new patented drugs in Germany. European reference prices (ERPs) are one criterion. The ERP is based on the ex-factory prices (EFPs) of the countries included in the European country basket. However, in some of these countries, the EFP is not published due to confidential wholesale margins. Wholesale margins must therefore be estimated and deducted from purchase prices. In this context literature-based estimates to date do not assume regressive margins with higher pharmaceutical prices. This assumption is questionable and can lead to systematically underestimated country prices, especially for high-priced drugs. Percentage wholesale margins in the majority of European countries develop to a comparable extent regressively with increasing prices. It should therefore be examined (1) whether statistical models can predict the margins of individual countries, in principle and especially for countries where margins are unknown and regressive trends are likely, and (2) to what extent the estimation of margins improves when regressive statistical models are used to estimate margins instead of cross-price averages published in the literature. METHODS: Qualitative preliminary research explores the basic wholesale pricing mechanisms in countries with confidential wholesale margins. Wholesale margins for reimbursable drugs were then modeled for regulated European countries. Estimation quality and impact of the model was compared to estimations based on average margins. RESULTS: In both regulated countries and in countries with confidential wholesale margins, percentage margins of wholesalers develop regressively as drug prices rise. Regressive courses of margins can be resiliently modeled for the regulated countries using a power distribution with significantly lower mean squared errors in a linear mixed model in comparison to literature-based estimations with country-specific cross-price averages. CONCLUSION: If there is reason to believe that margins are regressive, confidential wholesale margins are expected to be better estimated by the power function based on margins of regulated countries than by the published country-specific average margins, reducing significantly inaccurate effects on margin estimations of high-price drugs.

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