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BACKGROUND: Somatic hypermutation (SHM) status of the immunoglobulin heavy variable (IGHV) gene plays a crucial role in determining the prognosis and treatment of patients with chronic lymphocytic leukemia (CLL). A common approach for determining SHM status is multiplex polymerase chain reaction and Sanger sequencing of the immunoglobin heavy locus; however, this technique is low throughput, is vulnerable to failure, and does not allow multiplexing with other diagnostic assays. METHODS: Here we designed and validated a DNA targeted capture approach to detect immunoglobulin heavy variable somatic hypermutation (IGHV SHM) status as a submodule of a larger next-generation sequencing (NGS) panel that also includes probes for ATM, BIRC3, CHD2, KLHL6, MYD88, NOTCH1, NOTCH2, POT1, SF3B1, TP53, and XPO1. The assay takes as input FASTQ files and outputs a report containing IGHV SHM status and V allele usage following European Research Initiative on CLL guidelines. RESULTS: We validated the approach on 35 CLL patient samples, 34 of which were characterized using Sanger sequencing. The NGS panel identified the IGHV SHM status of 34 of 35 CLL patients. We showed 100% sensitivity and specificity among the 33 CLL samples with both NGS and Sanger sequencing calls. Furthermore, we demonstrated that this panel can be combined with additional targeted capture panels to detect prognostically important CLL single nucleotide variants, insertions/deletions, and copy number variants (TP53 copy number loss). CONCLUSIONS: A targeted capture approach to IGHV SHM detection can be integrated into broader sequencing panels, allowing broad CLL prognostication in a single molecular assay.
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Leucemia Linfocítica Crônica de Células B , Hipermutação Somática de Imunoglobulina , Humanos , Alelos , Sequenciamento de Nucleotídeos em Larga Escala , Imunoglobulinas , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/genética , Fatores de TranscriçãoRESUMO
PURPOSE: Contact lens wearers may inadvertently expose their lenses during the lens insertion and removal process or while wearing their lenses to cosmetic products being used. This study investigated the impact of various cosmetics on the physical dimension and optical properties of three recently marketed monthly replacement silicone hydrogel contact lenses. METHODS: In this in vitro study, three monthly replacement silicone hydrogel lens types including senofilcon C (ACUVUE VITA, Johnson & Johnson), samfilcon A (Bausch+Lomb ULTRA, Bausch+Lomb), and lotrafilcon B+EOBO (polyoxyethylene-polyoxybutylene) (AIR OPTIX plus HydraGlyde, ALCON), were individually coated with cosmetic products followed by a 1-hr soak in phosphate-buffered saline. Cosmetic products included; three hand creams (HC1: Glysomed; HC2: Vaseline Healthy Hand & Nail Conditioning; and HC3: Intense Relieve), three make-up removers (MR1: Lid-Care Towelettes; MR2: Gentle waterproof eye and Lip Makeup Remover; and MR3: Oil-Free Makeup Remover), and three mascaras (MA1: Great Lash-waterproof; MA2a: Wonder'Lash-waterproof, and MA3: Voluminous Original). The contact lens dimensions were determined for diameter, sagittal depth, and base curve, using the Chiltern (Optimec Limited), whereas lens power and optical quality were assessed using the Contest Plus II (Rotlex). Six replicates for each lens/cosmetic combination were used. The impact of cosmetics was tested between lenses and compared with uncoated control lenses. RESULTS: For lens diameter, makeup removers (MR2 & MR3) demonstrated the largest impact, with an increase of up to 0.26 mm (MR2) and 0.35 mm (MR3) for senofilcon C and samfilcon A, respectively (P<0.01 compared to baseline), whereas lotrafilcon B+EOBO showed a decrease of 0.01 mm (P<0.01 between lens types). For sagittal depth, mascara MA1 demonstrated the greatest impact, followed by makeup removers MR2 & MR3. All lenses showed increases in sagittal depth after MA1 exposure (0.16±0.06 mm in lotrafilcon B+EOBO, 0.24±0.22, and 0.26±0.09 mm in samfilcon A and senofilcon C, respectively; P<0.01 for all lenses compared with baseline). For base curve, the makeup removers (MR2 & MR3) caused increases for both senofilcon C (up to 0.36 mm) and samfilcon A (up to 0.35 mm), but lotrafilcon B+EOBO was unaffected. Lens power changes were generally minor (<0.25 D). However, senofilcon C showed a significant change of -1.18±0.65 D (more minus) after MA1 exposure (P<0.001). Image quality was most affected by mascaras, although given that all lens types were adversely affected to similar degrees, none of the lenses performed better or worse after mascara application (P>0.05). The parameters of the different lens types were not significantly affected by the hand creams. CONCLUSION: Makeup removers and mascaras changed the lens parameters to varying degrees, which may affect the fit and overall performance of the lens, whereas no such effect was noted with hand creams. Lotrafilcon B+EOBO was typically less affected compared with senofilcon C or samfilcon A.
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Lentes de Contato Hidrofílicas , Cosméticos/efeitos adversos , Hidrogéis , Silicones , Equipamentos Descartáveis , Humanos , Óptica e Fotônica , Ajuste de Prótese , Propriedades de Superfície/efeitos dos fármacosRESUMO
Experimental evolution (EE) is a powerful tool for addressing how environmental factors influence life-history evolution. While in nature different selection pressures experienced across the lifespan shape life histories, EE studies typically apply selection pressures one at a time. Here, we assess the consequences of adaptation to three different developmental diets in combination with classical selection for early or late reproduction in the fruit fly Drosophila melanogaster. We find that the response to each selection pressure is similar to that observed when they are applied independently, but the overall magnitude of the response depends on the selection regime experienced in the other life stage. For example, adaptation to increased age at reproduction increased lifespan across all diets; however, the extent of the increase was dependent on the dietary selection regime. Similarly, adaptation to a lower calorie developmental diet led to faster development and decreased adult weight, but the magnitude of the response was dependent on the age-at-reproduction selection regime. Given that multiple selection pressures are prevalent in nature, our findings suggest that trade-offs should be considered not only among traits within an organism, but also among adaptive responses to different-sometimes conflicting-selection pressures, including across life stages.
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Adaptação Fisiológica/genética , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Maturidade Sexual/fisiologia , Animais , Dieta , Feminino , Estágios do Ciclo de Vida , Masculino , Maturidade Sexual/genéticaRESUMO
BACKGROUND: Sub-optimal developmental diets often have adverse effects on long-term fitness and health. One hypothesis is that such effects are caused by mismatches between the developmental and adult environment, and may be mediated by persistent changes in gene expression. However, there are few experimental tests of this hypothesis. Here we address this using the fruit fly, Drosophila melanogaster. We vary diet during development and adulthood in a fully factorial design and assess the consequences for both adult life history traits and gene expression at middle and old age. RESULTS: We find no evidence that mismatches between developmental and adult diet are detrimental to either lifespan or fecundity. Rather, developmental and adult diet exert largely independent effects on both lifespan and gene expression, with adult diet having considerably more influence on both traits. Furthermore, we find effects of developmental diet on the transcriptome that persist into middle and old-age. Most of the genes affected show no correlation with the observed phenotypic effects of larval diet on lifespan. However, in each sex we identify a cluster of ribosome, transcription, and translation-related genes whose expression is altered across the lifespan and negatively correlated with lifespan. CONCLUSIONS: As several recent studies have linked decreased expression of ribosomal and transcription related proteins to increased lifespan, these provide promising candidates for mediating the effects of larval diet on lifespan. We place our findings in the context of theories linking developmental conditions to late-life phenotypes and discuss the likelihood that gene expression differences caused by developmental exposure causally relate to adult ageing phenotypes.
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Dieta , Drosophila melanogaster/genética , Fenótipo , Transcriptoma , Envelhecimento/genética , Animais , Drosophila melanogaster/fisiologia , Feminino , Larva/genética , Longevidade , Masculino , Especificidade de Órgãos , Testículo/metabolismoRESUMO
BACKGROUND: Energy drinks are popular mixers with alcohol. While energy drinks contain many ingredients, caffeine is an important pharmacologically active component and is generally present in larger amounts than in other caffeinated beverages. In these studies, we investigated the hypothesis that caffeine would influence the effects of alcohol (ethanol [EtOH]) on conditioned taste aversion (CTA), ataxia, and locomotor activity (LA) after repeated exposure. METHODS: Four groups of mice were exposed by oral gavage twice daily to vehicle, EtOH (4 g/kg), caffeine (15 mg/kg), or the EtOH/caffeine combination. CTA to saccharin and ataxia in the parallel rod task was evaluated after 8 or 16 gavages, respectively, using EtOH (1 to 3 g/kg) or EtOH/caffeine (3 mg/kg + 2 g/kg) challenges. In addition, LA was evaluated initially and after repeated exposure to oral gavage of these drugs and doses. RESULTS: Repeated oral gavage of EtOH produced significant locomotor sensitization, with those mice increasing total distance traveled by 2-fold. The locomotor response to caffeine, while significantly greater than vehicle gavage, did not change with repeated exposure. On the other hand, repeated gavage of caffeine/EtOH combination produced a substantial increase in total distance traveled after repeated exposure (~4-fold increase). After repeated EtOH exposure, there was significant tolerance to EtOH in the CTA and parallel rod tests. However, neither a history of caffeine exposure nor including caffeine influenced EtOH-induced CTA. Interestingly, a history of caffeine exposure increased the ataxic response to the caffeine/EtOH combination and appeared to reduce the ataxic response to high doses of EtOH. CONCLUSIONS: The data support the general hypothesis that repeated exposure to caffeine influences the response to EtOH. Together with previously published work, these data indicate that caffeine influences some EtOH-related behaviors, notably locomotion and ataxia, but appears not to influence the expression of conditioned behaviors.
Assuntos
Cafeína/administração & dosagem , Tolerância a Medicamentos , Etanol/administração & dosagem , Atividade Motora/efeitos dos fármacos , Animais , Ataxia/induzido quimicamente , Ataxia/prevenção & controle , Cafeína/toxicidade , Tolerância a Medicamentos/fisiologia , Etanol/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Atividade Motora/fisiologiaRESUMO
BACKGROUND: In 2005, the Indian government launched the National Rural Health Mission (NRHM) to improve the quality of and access to rural public health care. Despite these efforts, recent evidence shows that the rural poor continue to primarily consult private non-degree allopathic practitioners (NDAPs) for acute illness episodes. To examine this phenomenon, we explore the rural poor's perception and utilization of the rural health care system and the role and accessibility of NDAPs therein. METHODS: Our study is based on qualitative data from focus group discussions conducted in three rural districts in Bihar and Uttar Pradesh, two high-focus states of the NRHM in northern India, in 2009/2010. Our study population consists of female micro-credit self-help group members and their male household heads. We apply a directed content analysis and use a theoretical framework to differentiate between physical, financial and cultural access to care. RESULTS: Our study population distinguishes between "home treatment" (informal self-care), "local treatment" (formally unqualified care) and "outside treatment" (formally qualified care). Because of their proximity, flexible payment options and familiarity with patients' belief systems, among other things, local NDAPs are physically, financially and culturally accessible. They are usually the first contact points for patients before turning to qualified practitioners, and treat minor illnesses, provide first relief, refer patients to other providers and administer formally prescribed treatments. CONCLUSION: Our findings are similar for all three study sites and reinforce recent findings from southern and eastern India. The poor's understanding and utilization of the rural health system deviates from governmental ideas. Because of their embeddedness in the community, private NDAPs are the most accessible medical providers and first contact points for acute illness episodes. Thus, they de-facto fulfill the role envisaged by the Indian government for accredited social health activists introduced as part of the NRHM. We conclude that instead of trying to replace NDAPs with public initiatives, the Indian government should regulate, qualify and integrate them as part of the existing public health care system. This way, we argue, India can improve the rural poor's access to formally qualified practitioners.
Assuntos
Acreditação , Acessibilidade aos Serviços de Saúde , Serviços de Saúde Rural , Grupos de Autoajuda , Doença Aguda , Feminino , Pesquisa sobre Serviços de Saúde , Humanos , Índia , Masculino , Programas Nacionais de Saúde , Áreas de Pobreza , Pesquisa Qualitativa , Qualidade da Assistência à Saúde , População RuralRESUMO
Potentiation of metabotropic glutamate receptor subtype 5 (mGluR5) function produces antipsychotic-like and pro-cognitive effects in animal models of schizophrenia and can reverse cognitive deficits induced by N-methyl-D-aspartate type glutamate receptor (NMDAR) antagonists. However, it is currently unknown if mGluR5 positive allosteric modulators (PAMs) can modulate NMDAR antagonist-induced alterations in extracellular glutamate levels in regions underlying these cognitive and behavioral effects, such as the medial prefrontal cortex (mPFC). We therefore assessed the ability of the mGluR5 PAM, 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB), to reduce elevated extracellular glutamate levels induced by the NMDAR antagonist, dizocilpine (MK-801), in the mPFC. Male Sprague-Dawley rats were implanted with a guide cannula aimed at the mPFC and treated for ten consecutive days with MK-801 and CDPPB or their corresponding vehicles. CDPPB or vehicle was administered thirty minutes before MK-801 or vehicle each day. On the final day of treatment, in vivo microdialysis was performed, and samples were collected every thirty minutes to analyze extracellular glutamate levels. Compared to animals receiving only vehicle, administration of MK-801 alone significantly increased extracellular levels of glutamate in the mPFC. This effect was not observed in animals administered CDPPB before MK-801, nor in those administered CDPPB alone, indicating that CDPPB decreased extracellular glutamate release stimulated by MK-801. Results indicate that CDPPB attenuates MK-801 induced elevations in extracellular glutamate in the mPFC. This effect of CDPPB may underlie neurochemical adaptations associated with the pro-cognitive effects of mGluR5 PAMs in rodent models of schizophrenia.
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Balance and movement are impaired in a wide variety of neurological disorders. Recent advances in behavioral monitoring provide unprecedented access to posture and locomotor kinematics, but without the throughput and scalability necessary to screen candidate genes / potential therapeutics. We present a powerful solution: a Scalable Apparatus to Measure Posture and Locomotion (SAMPL). SAMPL includes extensible imaging hardware and low-cost open-source acquisition software with real-time processing. We first demonstrate that SAMPL's hardware and acquisition software can acquire data from from D. melanogaster, C. elegans, and D. rerio as they move vertically. Next, we leverage SAMPL's throughput to rapidly (two weeks) gather a new zebrafish dataset. We use SAMPL's analysis and visualization tools to replicate and extend our current understanding of how zebrafish balance as they navigate through a vertical environment. Next, we discover (1) that key kinematic parameters vary systematically with genetic background, and (2) that such background variation is small relative to the changes that accompany early development. Finally, we simulate SAMPL's ability to resolve differences in posture or vertical navigation as a function of affect size and data gathered -- key data for screens. Taken together, our apparatus, data, and analysis provide a powerful solution for labs using small animals to investigate balance and locomotor disorders at scale. More broadly, SAMPL is both an adaptable resource for labs looking process videographic measures of behavior in real-time, and an exemplar of how to scale hardware to enable the throughput necessary for screening.
RESUMO
Balance and movement are impaired in many neurological disorders. Recent advances in behavioral monitoring provide unprecedented access to posture and locomotor kinematics but without the throughput and scalability necessary to screen candidate genes/potential therapeutics. Here, we present a scalable apparatus to measure posture and locomotion (SAMPL). SAMPL includes extensible hardware and open-source software with real-time processing and can acquire data from D. melanogaster, C. elegans, and D. rerio as they move vertically. Using SAMPL, we define how zebrafish balance as they navigate vertically and discover small but systematic variations among kinematic parameters between genetic backgrounds. We demonstrate SAMPL's ability to resolve differences in posture and navigation as a function of effect size and data gathered, providing key data for screens. SAMPL is therefore both a tool to model balance and locomotor disorders and an exemplar of how to scale apparatus to support screens.
Assuntos
Caenorhabditis elegans , Drosophila melanogaster , Animais , Peixe-Zebra , Comportamento Animal , Locomoção , PosturaRESUMO
Follicular lymphoma (FL) is an indolent cancer of mature B-cells but with ongoing risk of transformation to more aggressive histology over time. Recurrent mutations associated with transformation have been identified; however, prognostic features that can be discerned at diagnosis could be clinically useful. We present here comprehensive profiling of both tumor and immune compartments in 155 diagnostic FL biopsies at single-cell resolution by mass cytometry. This revealed a diversity of phenotypes but included two recurrent patterns, one which closely resembles germinal center B-cells (GCB) and another which appears more related to memory B-cells (MB). GCB-type tumors are enriched for EZH2, TNFRSF14, and MEF2B mutations, while MB-type tumors contain increased follicular helper T-cells. MB-type and intratumoral phenotypic diversity are independently associated with increased risk of transformation, supporting biological relevance of these features. Notably, a reduced 26-marker panel retains sufficient information to allow phenotypic profiling of future cohorts by conventional flow cytometry.
Assuntos
Linfoma Folicular , Humanos , Linfoma Folicular/genética , Células B de Memória , Centro Germinativo , Linfócitos B , MutaçãoRESUMO
Although genetics shapes our sense of taste to prefer some foods over others, taste sensation is plastic and changes with age, disease state, and nutrition. We have known for decades that diet composition can influence the way we perceive foods, but many questions remain unanswered, particularly regarding the effects of chemosensory plasticity on feeding behavior. Here, we review recent evidence on the effects of high-nutrient diets, especially high dietary sugar, on sweet taste in vinegar flies, rodents, and humans, and discuss open questions about molecular and neural mechanisms and research priorities. We also consider ways in which diet-dependent chemosensory plasticity may influence food intake and play a role in the etiology of obesity and metabolic disease. Understanding the interplay between nutrition, taste sensation, and feeding will help us define the role of the food environment in mediating chronic disease and design better public health strategies to combat it.
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Dieta , Obesidade/fisiopatologia , Comportamento Alimentar/fisiologia , Humanos , Paladar/fisiologiaRESUMO
Mixing alcohol (ethanol) with caffeinated beverages continues to be a common and risky practice. Energy drinks are one type of caffeinated beverage that may be especially problematic when used as mixers, due to their relatively high caffeine content in combination with their highly sweetened flavor profile. The present study used a mouse model of limited-access drinking and lickometer circuitry to examine the effects of an energy drink anid its caffeine content on ethanol consumption. Predictably, the highly sweetened energy drink significantly increased ethanol intake compared to a plain ethanol solution (6.34 ± 0.2 vs. 5.01 ± 0.3 g/kg; Cohen's d = 1.79). Interestingly, adulterating a plain ethanol solution with the same concentration of caffeine (without sweetener) found in the energy drink also increased ethanol intake (5.47 ± 0.3 vs. 4.11 ± 0.3 g/kg; Cohen's d = 1.4). A lower concentration of caffeine was without effect on ethanol drinking. Interestingly, plain caffeine solutions at both tested concentrations provoked high numbers of bottle contacts, indicating that the mice found the solution palatable. These findings suggest that altering the bitterness profile of an ethanol solution with the addition of caffeine can increase intake in a similar manner as sweetening the solution. Further, the findings underscore the importance of taste in motivating ethanol consumption and the potential role that caffeine can have in this process.
Assuntos
Cafeína , Bebidas Energéticas , Consumo de Bebidas Alcoólicas , Animais , Cafeína/farmacologia , Etanol , Camundongos , EdulcorantesRESUMO
Next-generation sequencing assays are capable of identifying cancer patients eligible for targeted therapies and can also detect germline variants associated with increased cancer susceptibility. However, these capabilities have yet to be routinely harmonized in a single assay because of challenges with accurately identifying germline variants from tumor-only data. We have developed the Oncology and Hereditary Cancer Program targeted capture panel, which uses tumor tissue to simultaneously screen for both clinically actionable solid tumor variants and germline variants across 45 genes. Validation using 14 tumor specimens, composed of patient samples and cell lines analyzed in triplicate, demonstrated high coverage with sensitive and specific identification of single-nucleotide variants and small insertions and deletions. Average coverage across all targets remained >2000× in 198 additional patient tumor samples. Analysis of 55 formalin-fixed, paraffin-embedded tumor samples for the detection of known germline variants within a subset of cancer-predisposition genes, including one multiexon deletion, yielded a 100% detection rate, demonstrating that germline variants can be reliably detected in tumor samples using a single panel. Combining targetable somatic and actionable germline variants into a single tumor tissue assay represents a streamlined approach that can inform treatment for patients with advanced cancers as well as identify those with potential germline variants who are eligible for confirmatory testing, but would not otherwise have been identified.
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Predisposição Genética para Doença/genética , Células Germinativas , Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias/diagnóstico , Neoplasias/genética , Alelos , Estudos de Coortes , Variações do Número de Cópias de DNA , Confiabilidade dos Dados , Feminino , Testes Genéticos/métodos , Humanos , Mutação INDEL , Polimorfismo de Nucleotídeo Único , Prognóstico , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: The anti-infective agent Taurolidine (TRD) has been shown to have cell death inducing properties, but the mechanism of its action is largely unknown. The aim of this study was to identify potential common target genes modulated at the transcriptional level following TRD treatment in tumour cell lines originating from different cancer types. METHODS: Five different malignant cell lines (HT29, Chang Liver, HT1080, AsPC-1 and BxPC-3) were incubated with TRD (100 µM, 250 µM and 1000 µM). Proliferation after 8 h and cell viability after 24 h were analyzed by BrdU assay and FACS analysis, respectively. Gene expression analyses were carried out using the Agilent-microarray platform to identify genes which displayed conjoint regulation following the addition of TRD in all cell lines. Candidate genes were subjected to Ingenuity Pathways Analysis and selected genes were validated by qRT-PCR and Western Blot. RESULTS: TRD 250 µM caused a significant inhibition of proliferation as well as apoptotic cell death in all cell lines. Among cell death associated genes with the strongest regulation in gene expression, we identified pro-apoptotic transcription factors (EGR1, ATF3) as well as genes involved in the ER stress response (PPP1R15A), in ubiquitination (TRAF6) and mitochondrial apoptotic pathways (PMAIP1). CONCLUSIONS: This is the first conjoint analysis of potential target genes of TRD which was performed simultaneously in different malignant cell lines. The results indicate that TRD might be involved in different signal transduction pathways leading to apoptosis.
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Regulação Neoplásica da Expressão Gênica , Taurina/análogos & derivados , Tiadiazinas/farmacologia , Antineoplásicos/farmacologia , Apoptose , Morte Celular , Linhagem Celular Tumoral , Proliferação de Células , Separação Celular , Sobrevivência Celular , Citometria de Fluxo , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Taurina/farmacologia , Transcrição GênicaRESUMO
From humans to vinegar flies, exposure to diets rich in sugar and fat lowers taste sensation, changes food choices, and promotes feeding. However, how these peripheral alterations influence eating is unknown. Here we used the genetically tractable organism D. melanogaster to define the neural mechanisms through which this occurs. We characterized a population of protocerebral anterior medial dopaminergic neurons (PAM DANs) that innervates the ß'2 compartment of the mushroom body and responds to sweet taste. In animals fed a high sugar diet, the response of PAM-ß'2 to sweet stimuli was reduced and delayed, and sensitive to the strength of the signal transmission out of the sensory neurons. We found that PAM-ß'2 DANs activity controls feeding rate and satiation: closed-loop optogenetic activation of ß'2 DANs restored normal eating in animals fed high sucrose. These data argue that diet-dependent alterations in taste weaken satiation by impairing the central processing of sensory signals.
Obesity is a major health problem affecting over 650 million adults worldwide. It is typically caused by overeating high-energy foods, which often contain a lot of sugar. Consuming sugary foods triggers the production of a reward signal called dopamine in the brains of insects and mammals, which reinforces sugar-consuming behavior. The brain balances this with a process called 'sensory-enhanced satiety', which makes foods that provide a stronger sensation of sweetness better at reducing hunger and further eating. High-energy food was scarce for most of human evolution, but over the past century sugar has become readily available in our diet leading to an increase in obesity. Last year, a study in fruit flies reported that a sugary diet reduces the sensitivity to sweet flavors, which leads to overeating and weight gain. It appears that this sensitivity is linked to the effectiveness of sensory-enhanced satiety. However, the mechanism linking diets high in sugar and overeating is still poorly understood. One hypothesis is that fruit flies estimate the energy content of food based on the degree of dopamine released in response to the sugar. May et al. compared the responses of neurons in fruit flies fed a normal diet to those in flies fed a diet high in sugar. As expected, both groups activated the neurons involved in the dopamine reward response when they tasted sugar. However, when the flies were on a sugar-heavy diet, these neurons were less active. This was because the neurons responsible for tasting sweetness were activated less in flies fed a high-sugar diet, leading to a lowered response by the neurons that produce dopamine. The flies in these experiments were genetically engineered so that the dopamine-producing neurons could be artificially activated in response to light, a technique called optogenetics. When May et al. applied this technique to the flies on a sugar-heavy diet, they were able to stop these flies from overeating. These findings provide further evidence to support the idea that a sugary diet reduces the brain's sensitivity to overeating. Given the significant healthcare cost of obesity to society, this improved understanding could help public health initiatives focusing on manufacturing food that is lower in sugar.
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Açúcares da Dieta/administração & dosagem , Neurônios Dopaminérgicos , Drosophila melanogaster/fisiologia , Sacarose/metabolismo , Percepção Gustatória , Animais , Animais Geneticamente Modificados/fisiologia , MasculinoRESUMO
Diets rich in sugar, salt, and fat alter taste perception and food preference, contributing to obesity and metabolic disorders, but the molecular mechanisms through which this occurs are unknown. Here, we show that in response to a high sugar diet, the epigenetic regulator Polycomb Repressive Complex 2.1 (PRC2.1) persistently reprograms the sensory neurons of Drosophila melanogaster flies to reduce sweet sensation and promote obesity. In animals fed high sugar, the binding of PRC2.1 to the chromatin of the sweet gustatory neurons is redistributed to repress a developmental transcriptional network that modulates the responsiveness of these cells to sweet stimuli, reducing sweet sensation. Half of these transcriptional changes persist despite returning the animals to a control diet, causing a permanent decrease in sweet taste. Our results uncover a new epigenetic mechanism that, in response to the dietary environment, regulates neural plasticity and feeding behavior to promote obesity.
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Proteínas de Drosophila , Drosophila melanogaster , Animais , Dieta , Proteínas de Drosophila/genética , Drosophila melanogaster/fisiologia , Epigênese Genética , Obesidade/genética , Células Receptoras Sensoriais/metabolismo , Açúcares , Paladar/fisiologiaRESUMO
In the mouse, the osteoblast-derived hormone Lipocalin-2 (LCN2) suppresses food intake and acts as a satiety signal. We show here that meal challenges increase serum LCN2 levels in persons with normal or overweight, but not in individuals with obesity. Postprandial LCN2 serum levels correlate inversely with hunger sensation in challenged subjects. We further show through brain PET scans of monkeys injected with radiolabeled recombinant human LCN2 (rh-LCN2) and autoradiography in baboon, macaque, and human brain sections, that LCN2 crosses the blood-brain barrier and localizes to the hypothalamus in primates. In addition, daily treatment of lean monkeys with rh-LCN2 decreases food intake by 21%, without overt side effects. These studies demonstrate the biology of LCN2 as a satiety factor and indicator and anorexigenic signal in primates. Failure to stimulate postprandial LCN2 in individuals with obesity may contribute to metabolic dysregulation, suggesting that LCN2 may be a novel target for obesity treatment.
Obesity has reached epidemic proportions worldwide and affects more than 40% of adults in the United States. People with obesity have a greater likelihood of developing type 2 diabetes, cardiovascular disease or chronic kidney disease. Changes in diet and exercise can be difficult to follow and result in minimal weight loss that is rarely sustained overtime. In fact, in people with obesity, weight loss can lower the metabolism leading to increased weight gain. New drugs may help some individuals achieve 5 to 10% weight loss but have side effects that prevent long-term use. Previous studies in mice show that a hormone called Lipocalin-2 (LCN2) suppresses appetite. It also reduces body weight and improves sugar metabolism in the animals. But whether this hormone has the same effects in humans or other primates is unclear. If it does, LCN2 might be a potential obesity treatment. Now, Petropoulou et al. show that LCN2 suppressed appetite in humans and monkeys. In human studies, LCN2 levels increased after a meal in individuals with normal weight or overweight, but not in individuals with obesity. Higher levels of LCN2 in a person's blood were also associated with a feeling of reduced hunger. Using brain scans, Petropoulou et al. showed that LCN2 crossed the blood-brain barrier in monkeys and bound to the hypothalamus, the brain center regulating appetite and energy balance. LCN2 also bound to human and monkey hypothalamus tissue in laboratory experiments. When injected into monkeys, the hormone suppressed food intake and lowered body weight without toxic effects in short-term studies. The experiments lay the initial groundwork for testing whether LCN2 might be a useful treatment for obesity. More studies in animals will help scientists understand how LCN2 works, which patients might benefit, how it would be given to patients and for how long. Clinical trials would also be needed to verify whether it is an effective and safe treatment for obesity.
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Lipocalina-2/metabolismo , Macaca/metabolismo , Obesidade/metabolismo , Papio/metabolismo , Animais , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Ingestão de Alimentos , Humanos , Lipocalina-2/genética , Obesidade/diagnóstico por imagem , Obesidade/genética , Obesidade/fisiopatologia , Tomografia por Emissão de Pósitrons , Transporte ProteicoRESUMO
Recent studies find that sugar tastes less intense to humans with obesity, but whether this sensory change is a cause or a consequence of obesity is unclear. To tackle this question, we study the effects of a high sugar diet on sweet taste sensation and feeding behavior in Drosophila melanogaster. On this diet, fruit flies have lower taste responses to sweet stimuli, overconsume food, and develop obesity. Excess dietary sugar, but not obesity or dietary sweetness alone, caused taste deficits and overeating via the cell-autonomous action of the sugar sensor O-linked N-Acetylglucosamine (O-GlcNAc) transferase (OGT) in the sweet-sensing neurons. Correcting taste deficits by manipulating the excitability of the sweet gustatory neurons or the levels of OGT protected animals from diet-induced obesity. Our work demonstrates that the reshaping of sweet taste sensation by excess dietary sugar drives obesity and highlights the role of glucose metabolism in neural activity and behavior.
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Açúcares da Dieta/farmacologia , Drosophila melanogaster/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Paladar/efeitos dos fármacos , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Obesidade/patologia , Sinapses/efeitos dos fármacos , Sinapses/fisiologiaAssuntos
Ciclídeos/fisiologia , Comportamento Sexual Animal/fisiologia , Comunicação Animal , Animais , Feminino , Masculino , Ruído , ReproduçãoRESUMO
Both developmental nutrition and adult nutrition affect life-history traits; however, little is known about whether the effect of developmental nutrition depends on the adult environment experienced. We used the fruit fly to determine whether life-history traits, particularly life span and fecundity, are affected by developmental nutrition, and whether this depends on the extent to which the adult environment allows females to realize their full reproductive potential. We raised flies on three different developmental food levels containing increasing amounts of yeast and sugar: poor, control, and rich. We found that development on poor or rich larval food resulted in several life-history phenotypes indicative of suboptimal conditions, including increased developmental time, and, for poor food, decreased adult weight. However, development on poor larval food actually increased adult virgin life span. In addition, we manipulated the reproductive potential of the adult environment by adding yeast or yeast and a male. This manipulation interacted with larval food to determine adult fecundity. Specifically, under two adult conditions, flies raised on poor larval food had higher reproduction at certain ages - when singly mated this occurred early in life and when continuously mated with yeast this occurred during midlife. We show that poor larval food is not necessarily detrimental to key adult life-history traits, but does exert an adult environment-dependent effect, especially by affecting virgin life span and altering adult patterns of reproductive investment. Our findings are relevant because (1) they may explain differences between published studies on nutritional effects on life-history traits; (2) they indicate that optimal nutritional conditions are likely to be different for larvae and adults, potentially reflecting evolutionary history; and (3) they urge for the incorporation of developmental nutritional conditions into the central life-history concept of resource acquisition and allocation.