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The gp130 receptor cytokines IL-6 and CNTF improve metabolic homeostasis but have limited therapeutic use for the treatment of type 2 diabetes. Accordingly, we engineered the gp130 ligand IC7Fc, in which one gp130-binding site is removed from IL-6 and replaced with the LIF-receptor-binding site from CNTF, fused with the Fc domain of immunoglobulin G, creating a cytokine with CNTF-like, but IL-6-receptor-dependent, signalling. Here we show that IC7Fc improves glucose tolerance and hyperglycaemia and prevents weight gain and liver steatosis in mice. In addition, IC7Fc either increases, or prevents the loss of, skeletal muscle mass by activation of the transcriptional regulator YAP1. In human-cell-based assays, and in non-human primates, IC7Fc treatment results in no signs of inflammation or immunogenicity. Thus, IC7Fc is a realistic next-generation biological agent for the treatment of type 2 diabetes and muscle atrophy, disorders that are currently pandemic.
Assuntos
Receptor gp130 de Citocina/metabolismo , Citocinas/síntese química , Citocinas/uso terapêutico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Imunoglobulina G/uso terapêutico , Proteínas Recombinantes de Fusão/uso terapêutico , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Ligação Competitiva , Citocinas/química , Diabetes Mellitus Tipo 2/metabolismo , Desenho de Fármacos , Fígado Gorduroso/prevenção & controle , Teste de Tolerância a Glucose , Humanos , Hiperglicemia/tratamento farmacológico , Hiperglicemia/metabolismo , Incretinas/metabolismo , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Masculino , Camundongos , Músculo Esquelético/efeitos dos fármacos , Obesidade/metabolismo , Pâncreas/metabolismo , Fosfoproteínas/metabolismo , Engenharia de Proteínas , Receptores de Interleucina-6/metabolismo , Transdução de Sinais , Fatores de Transcrição , Aumento de Peso/efeitos dos fármacos , Proteínas de Sinalização YAPRESUMO
PURPOSE OF REVIEW: The recent (re)discovery of the meningeal lymphatic has brought a new player in brain neurophysiology. This review highlights the state of the current research on the meningeal lymphatic vasculature, from its specific physiology to its increasing implication in normal and pathological brain function. RECENT FINDINGS: Growing evidence are emerging about the uniqueness of the meningeal lymphatic vasculature and its implication in multiple neurological and neurotraumatic disorders. SUMMARY: These studies are highlighting a new and unexpected role for the lymphatic vasculature in brain function and a potential new therapeutic target for neurological disorders.
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Vasos Linfáticos , Meninges , Encéfalo , Humanos , Sistema Linfático , Vasos Linfáticos/fisiologia , Meninges/patologia , Meninges/fisiologiaRESUMO
Autophagy is critical for maintaining cellular function via clearance of excess nutrients and damaged organelles. In pancreatic ß-cells, it helps counter the endoplasmic reticulum (ER) stress that impairs insulin secretory capacity during Type 2 diabetes. Chronic exposure of ß-cells to saturated fatty acids (FAs) such as palmitate stimulates ER stress and modulates autophagy, but the effects of unsaturated FAs such as oleate, which are also elevated during obesity, are less well understood. We therefore treated MIN6 cells and mouse islets for 8-48 h with either palmitate or oleate, and then monitored autophagic flux, signaling pathways, lysosomal biology, and phospholipid profiles. Compared with palmitate, oleate more effectively stimulated both autophagic flux and clearance of autophagosomes. The flux stimulation occurred independently of ER stress, nutrient-sensing (mTOR) and signaling pathways (protein kinases A, C, and D). Instead the mechanism involved the exchange factor directly activated by cAMP 2 (EPAC2). Oleate reduced cellular cAMP, and its effects on autophagic flux were reproduced or inhibited, respectively, by Epac2 knockdown or activation. Oleate also increased lysosomal acidity and increased phospholipid saturation, consistent with improved autophagosomal fusion with lysosomes. We conclude that a potent stimulation of autophagy might help explain the known benefits of unsaturated FAs in countering the toxicity of saturated FAs in ß-cells during obesity and lipid loading.
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Apoptose/efeitos dos fármacos , AMP Cíclico/antagonistas & inibidores , Células Secretoras de Insulina/efeitos dos fármacos , Ácido Oleico/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , AMP Cíclico/metabolismo , Fatores de Troca do Nucleotídeo Guanina/antagonistas & inibidores , Fatores de Troca do Nucleotídeo Guanina/deficiência , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Células Tumorais CultivadasRESUMO
Fatty acid receptors have been recognized as important players in glycaemic control. This study is the first to describe a role for the medium-chain fatty acid (MCFA) receptor G-protein-coupled receptor (Gpr) 84 in skeletal muscle mitochondrial function and insulin secretion. We are able to show that Gpr84 is highly expressed in skeletal muscle and adipose tissue. Mice with global deletion of Gpr84 [Gpr84 knockout (KO)] exhibit a mild impairment in glucose tolerance when fed a MCFA-enriched diet. Studies in mice and pancreatic islets suggest that glucose intolerance is accompanied by a defect in insulin secretion. MCFA-fed KO mice also exhibit a significant impairment in the intrinsic respiratory capacity of their skeletal muscle mitochondria, but at the same time also exhibit a substantial increase in mitochondrial content. Changes in canonical pathways of mitochondrial biogenesis and turnover are unable to explain these mitochondrial differences. Our results show that Gpr84 plays a crucial role in regulating mitochondrial function and quality control.-Montgomery, M. K., Osborne, B., Brandon, A. E., O'Reilly, L., Fiveash, C. E., Brown, S. H. J., Wilkins, B. P., Samsudeen, A., Yu, J., Devanapalli, B., Hertzog, A., Tolun, A. A., Kavanagh, T., Cooper, A. A., Mitchell, T. W., Biden, T. J., Smith, N. J., Cooney, G. J., Turner, N. Regulation of mitochondrial metabolism in murine skeletal muscle by the medium-chain fatty acid receptor Gpr84.
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Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Receptores Acoplados a Proteínas G/fisiologia , Animais , Composição Corporal , Glucose/metabolismo , Resistência à Insulina , Lipídeos/análise , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/química , Receptores Acoplados a Proteínas G/genéticaRESUMO
AIMS/HYPOTHESIS: Defective beta cell function during lipid oversupply and type 2 diabetes is associated with dysregulation of lysosomal function and autophagy. Whether this dysregulation represents augmentation or inhibition is unclear because of technical limitations in assaying autophagy. The current aim was to determine the effects of high-fat feeding on true autophagic flux in beta cells in vivo in mice, and to establish the relationship between autophagy, endoplasmic reticulum (ER) stress and apoptosis. METHODS: Green fluorescent protein-microtubule-associated protein 1 light chain 3 (GFP-LC3) mice were fed chow or high-fat diets for 8-10 weeks and injected with 100 mg kg(-1) day(-1) chloroquine for 5 days, prior to being killed, to block clearance of autophagic markers. Pancreases and livers were fixed and GFP-LC3 aggregates or autophagosomes were detected by fluorescence or electron microscopy, respectively. Independently, islets isolated from chow or high-fat-fed mice were treated for 2 h with chloroquine ex vivo, and immunoblotting was performed for markers of autophagy (LC3 lipidation - LC3II and p62/SQSTM1), ER stress (C/EBP homology protein [CHOP], phosphorylated eukaryotic initiation factor 2α [p-eIFα] and inositol requiring enzyme 1α [p-IRE1α]) and apoptosis (cleaved caspase-3). RESULTS: Numbers of autophagosomes and GFP puncta were increased in beta cells by combined high-fat feeding and chloroquine injection, indicative of enhanced autophagic flux. By contrast, GFP puncta were attenuated in liver under the same conditions. Relative to chow-fed controls, islets isolated from fat-fed mice exhibited higher LC3II levels when treated ex vivo with chloroquine. The combination of high-fat feeding and acute chloroquine treatment induced CHOP, p-eIF2α and caspase-3, but not either treatment alone. CONCLUSIONS/INTERPRETATION: We provide the first in vivo demonstrations that high-fat feeding increases autophagic flux in pancreatic beta cells, and that this serves to protect against induction of terminal ER stress. We also highlight an approach for monitoring dietary alterations in autophagic flux using ex vivo manipulation of isolated islets.
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Diabetes Mellitus Tipo 2/sangue , Dieta Hiperlipídica , Células Secretoras de Insulina/citologia , Animais , Apoptose , Autofagia , Caspase 3/metabolismo , Cloroquina/química , Retículo Endoplasmático/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Homozigoto , Lipídeos/química , Lisossomos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Confocal , Microscopia Eletrônica , Microscopia de Fluorescência , Proteínas Associadas aos Microtúbulos/metabolismo , Fator de Transcrição CHOP/metabolismoRESUMO
Frailty is common among older hospital inpatients. While studies describe frailty prevalence in acute hospitals, it is usually based upon retrospective hospital-coded data or brief screening on admission rather than comprehensive geriatric assessment (CGA). Further, little is known about differences between pre-admission and current frailty status. Given this, we investigated the prevalence of pre-frailty and frailty among adult inpatients in a large university hospital after CGA. Of the 410 inpatients available, 398 were included in the study, with a median age of 70 years; 56% were male. The median length of stay (LOS) at review was 8 days. The point prevalence of frailty was 30% versus 14% for pre-frailty. The median Clinical Frailty Scale score pre-admission was 3/9, which was significantly lower than at review, which was 4/9 (p < 0.001). After adjusting for age and sex, frailty was associated with greater odds of prolonged LOS (odds ratio [OR] 1.7, p = 0.045), one-year mortality (OR 2.1, p = 0.006), and one-year institutionalisation (OR 9, p < 0.001) but not re-admission. Frailty was most prevalent on medical and orthopaedic wards. In conclusion, CGA is an important risk assessment for hospitalised patients. Frailty was highly prevalent and associated with poor healthcare outcomes. Frailty status appears to worsen significantly during admission, likely reflecting acute illness, and it may not reflect a patient's true frailty level. The development of frailty clinical care pathways is recommended in order to address the poor prognosis associated with a diagnosis of frailty in this setting.
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Fragilidade , Humanos , Masculino , Idoso , Adulto , Feminino , Fragilidade/epidemiologia , Fragilidade/diagnóstico , Prevalência , Idoso Fragilizado , Estudos Retrospectivos , Tempo de Internação , Hospitais , Avaliação GeriátricaRESUMO
With increasing evidence of electroreception in terrestrial arthropods, an understanding of receptor level processes is vital to appreciating the capabilities and limits of this sense. Here, we examine the spatio-temporal sensitivity of mechanoreceptive filiform hairs in detecting electrical fields. We first present empirical data, highlighting the time-varying characteristics of biological electrical signals. After which, we explore how electrically sensitive hairs may respond to such stimuli. The main findings are: (i) oscillatory signals (elicited by wingbeats) influence the spatial sensitivity of hairs, unveiling an inextricable spatio-temporal link; (ii) wingbeat direction modulates spatial sensitivity; (iii) electrical wingbeats can be approximated by sinusoidally modulated DC signals; and (iv) for a moving point charge, maximum sensitivity occurs at a faster timescale than a hair's frequency-based tuning. Our results show that electro-mechanical sensory hairs may capture different spatio-temporal information, depending on an object's movement and wingbeat and in comparison with aero-acoustic stimuli. Crucially, we suggest that electrostatic and aero-acoustic signals may provide distinguishable channels of information for arthropods. Given the pervasiveness of electric fields in nature, our results suggest further study to understand electrostatics in the ecology of arthropods and to reveal unknown ecological relationships and novel interactions between species.
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Artrópodes , Animais , Movimento , Eletricidade , Cabelo , Eletricidade EstáticaRESUMO
We have exploited islet-associated macrophages (IAMs) as a model of resident macrophage function, focusing on more physiological conditions than the commonly used extremes of M1 (inflammation) versus M2 (tissue remodeling) polarization. Under steady state, murine IAMs are metabolically poised between aerobic glycolysis and oxidative phosphorylation, and thereby exert a brake on glucose-stimulated insulin secretion (GSIS). This is underpinned by epigenetic remodeling via the metabolically regulated histone demethylase Kdm5a. Conversely, GSIS is enhanced by engaging Axl receptors on IAMs, or by augmenting their oxidation of glucose. Following high-fat feeding, efferocytosis is stimulated in IAMs in conjunction with Mertk and TGFß receptor signaling. This impairs GSIS and potentially contributes to ß-cell failure in pre-diabetes. Thus, IAMs serve as relays in many more settings than currently appreciated, fine-tuning insulin secretion in response to dynamic changes in the external environment. Intervening in this nexus might represent a means of preserving ß-cell function during metabolic disease.
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The atmosphere hosts multiple sources of electric charge that influence critical processes such as the aggregation of droplets and the removal of dust and aerosols. This is evident in the variability of the atmospheric electric field. Whereas these electric fields are known to respond to physical and geological processes, the effect of biotic sources of charge has not hitherto been considered. Here, we combine theoretical and empirical evidence to demonstrate that honeybee swarms directly contribute to atmospheric electricity, in proportion to the swarm density. We provide a quantitative assessment of this finding, by comparing the electrical contribution of various swarming insect species with common abiotic sources of charge. This reveals that the charge contribution of some insect swarms will be comparable with that of meteorologically induced variations. The observed transport of charge by insects therefore demonstrates an unexplored role of biogenic space charge for physical and ecological processes in the atmosphere.
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The Association for Respiratory Technology & Physiology (ARTP) last produced a statement on the performance of lung function testing in 1994. At that time the focus was on a practical statement for people working in lung function laboratories. Since that time there have been many technological advances and alterations to best practice in the measurement and interpretation of lung function assessments. In light of these advances an update was warranted. ARTP, therefore, have provided within this document, where available, the most up-to-date and evidence-based recommendations for the most common lung function assessments performed in laboratories across the UK. These recommendations set out the requirements and considerations that need to be made in terms of environmental and patient factors that may influence both the performance and interpretation of lung function tests. They also incorporate procedures to ensure quality assured diagnostic investigations that include those associated with equipment, the healthcare professional conducting the assessments and the results achieved by the subject. Each section aims to outline the common parameters provided for each investigation, a brief principle behind the measurements (where applicable), and suggested acceptability and reproducibility criteria.
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Laboratórios/normas , Testes de Função Respiratória/métodos , Humanos , Controle de Qualidade , Sociedades Médicas , Reino UnidoRESUMO
Emitting ultrasound upon hearing an attacking bat is an effective defence strategy used by several moth taxa. Here we reveal how Yponomeuta moths acquire sophisticated acoustic protection despite being deaf themselves and hence unable to respond to bat attacks. Instead, flying Yponomeuta produce bursts of ultrasonic clicks perpetually; a striated patch in their hind wing clicks as the beating wing rotates and bends. This wing structure is strikingly similar to the thorax tymbals with which arctiine moths produce their anti-bat sounds. And indeed, Yponomeuta sounds closely mimic such arctiine signals, revealing convergence in form and function. Because both moth taxa contain noxious compounds, we conclude they are mutual Müllerian acoustic mimics. Yponomeuta's perpetual clicking would however also attract bat predators. In response, their click amplitude is reduced and affords acoustic protection just as far as required, matching the distance over which bat biosonar would pick up Yponomeuta echoes anyway - advanced acoustic defences for a deaf moth.
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Mimetismo Biológico , Mariposas/fisiologia , Vocalização Animal , Asas de Animais/fisiologia , Animais , Quirópteros/fisiologia , Ondas UltrassônicasRESUMO
Early identification of frailty through targeted screening can facilitate the delivery of comprehensive geriatric assessment (CGA) and may improve outcomes for older inpatients. As several instruments are available, we aimed to investigate which is the most accurate and reliable in the Emergency Department (ED). We compared the ability of three validated, short, frailty screening instruments to identify frailty in a large University Hospital ED. Consecutive patients aged ≥70 attending ED were screened using the Clinical Frailty Scale (CFS), Identification of Seniors at Risk Tool (ISAR), and the Programme on Research for Integrating Services for the Maintenance of Autonomy 7 item questionnaire (PRISMA-7). An independent CGA using a battery of assessments determined each patient's frailty status. Of the 280 patients screened, complete data were available for 265, with a median age of 79 (interquartile ±9); 54% were female. The median CFS score was 4/9 (±2), ISAR 3/6 (±2), and PRISMA-7 was 3/7 (±3). Based upon the CGA, 58% were frail and the most accurate instrument for separating frail from non-frail was the PRISMA-7 (AUC 0.88; 95% CI:0.83-0.93) followed by the CFS (AUC 0.83; 95% CI:0.77-0.88), and the ISAR (AUC 0.78; 95% CI:0.71-0.84). The PRISMA-7 was statistically significantly more accurate than the ISAR (p = 0.008) but not the CFS (p = 0.15). Screening for frailty in the ED with a selection of short screening instruments, but particularly the PRISMA-7, is reliable and accurate.
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Serviço Hospitalar de Emergência , Idoso Fragilizado , Fragilidade/diagnóstico , Avaliação Geriátrica/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Medição de Risco , Sensibilidade e Especificidade , TriagemRESUMO
Protein kinase C epsilon (PKCÉ) activation in the liver is proposed to inhibit insulin action through phosphorylation of the insulin receptor. Here, however, we demonstrated that global, but not liver-specific, deletion of PKCÉ in mice protected against diet-induced glucose intolerance and insulin resistance. Furthermore, PKCÉ-dependent alterations in insulin receptor phosphorylation were not detected. Adipose-tissue-specific knockout mice did exhibit improved glucose tolerance, but phosphoproteomics revealed no PKCÉ-dependent effect on the activation of insulin signaling pathways. Altered phosphorylation of adipocyte proteins associated with cell junctions and endosomes was associated with changes in hepatic expression of several genes linked to glucose homeostasis and lipid metabolism. The primary effect of PKCÉ on glucose homeostasis is, therefore, not exerted directly in the liver as currently posited, and PKCÉ activation in this tissue should be interpreted with caution. However, PKCÉ activity in adipose tissue modulates glucose tolerance and is involved in crosstalk with the liver.
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Tecido Adiposo/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Proteína Quinase C-épsilon/fisiologia , Animais , Dieta Hiperlipídica , Técnicas de Inativação de Genes , Intolerância à Glucose , Resistência à Insulina , Metabolismo dos Lipídeos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Quinase C-épsilon/genéticaRESUMO
Behavioral observation techniques which relate action to personality have long been neglected (Furr and Funder in Handbook of research methods in personality psychology, The Guilford Press, New York, 2007) and, when employed, often use human judges to code behavior. In the current study we used an alternative to human coding (biomechanical research techniques) to investigate how personality traits are manifest in gait. We used motion capture technology to record 29 participants walking on a treadmill at their natural speed. We analyzed their thorax and pelvis movements, as well as speed of gait. Participants completed personality questionnaires, including a Big Five measure and a trait aggression questionnaire. We found that gait related to several of our personality measures. The magnitude of upper body movement, lower body movement, and walking speed, were related to Big Five personality traits and aggression. Here, we present evidence that some gait measures can relate to Big Five and aggressive personalities. We know of no other examples of research where gait has been shown to correlate with self-reported measures of personality and suggest that more research should be conducted between largely automatic movement and personality.
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This study used a novel research paradigm to examine gait control during real-time between-person collision avoidance. Ten young adults (M=20.1±1.52years) were required to walk across a six metre simulated pedestrian crossing, while avoiding a collision with one or two oncoming pedestrians. The potential for social interaction was manipulated by having the oncoming pedestrians walk with (2MP) or without (2P) looking at a mobile phone. Participants took longer to complete the crossing when avoiding a collision with two oncoming pedestrians (2MP: M=5.68s; 2P: M=5.74s) in comparison with baseline (M=4.96s). Gait velocity decreased and was more variable when avoiding a collision during the 2P condition, whilst the anterior-posterior separation distance between pedestrians and the participants at the initiation of peak mediolateral deviation was significantly smaller in 2MP compared to 2P. These findings offer preliminary understanding on how gait control may be adapted to changes in the availability of other persons' gaze orientation information. Future work is needed to further understand how different adaptive behaviours emerge relative to other persons during pedestrian crossings.
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Acidentes de Trânsito/prevenção & controle , Simulação por Computador , Marcha/fisiologia , Orientação Espacial/fisiologia , Pedestres , Caminhada/fisiologia , Adulto , Feminino , Humanos , Masculino , Segurança , Adulto JovemRESUMO
Transglutaminase type 2 (TG2) has been reported to be a candidate gene for maturity onset diabetes of the young (MODY) because three different mutations that impair TG2 transamidase activity have been found in 3 families with MODY. TG2 null (TG2(-/-)) mice have been reported to be glucose intolerant and have impaired glucose-stimulated insulin secretion (GSIS). Here we rigorously evaluated the role of TG2 in glucose metabolism using independently generated murine models of genetic TG2 disruption, which show no compensatory enhanced expression of other TGs in pancreatic islets or other tissues. First, we subjected chow- or fat-fed congenic SV129 or C57BL/6 wild type (WT) and TG2(-/-) littermates, to oral glucose gavage. Blood glucose and serum insulin levels were similar for both genotypes. Pancreatic islets isolated from these animals and analysed in vitro for GSIS and cholinergic potentiation of GSIS, showed no significant difference between genotypes. Results from intraperitoneal glucose tolerance tests (GTTs) and insulin tolerance tests (ITTs) were similar for both genotypes. Second, we directly investigated the role of TG2 transamidase activity in insulin secretion using a coisogenic model that expresses a mutant form of TG2 (TG2(R579A)), which is constitutively active for transamidase activity. Intraperitoneal GTTs and ITTs revealed no significant differences between WT and TG2(R579A/R579A) mice. Given that neither deletion nor constitutive activation of TG2 transamidase activity altered basal responses, or responses to a glucose or insulin challenge, our data indicate that glucose homeostasis in mice is TG2 independent, and question a link between TG2 and diabetes.