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Cyclization provides a general strategy for improving the proteolytic stability, cell membrane permeability and target binding affinity of peptides. Insertion of a stable, non-reducible linker into a disulphide bond is a commonly used approach for cyclizing phage-displayed peptides. However, among the vast collection of cysteine reactive linkers available, few provide the selectivity required to target specific cysteine residues within the peptide in the phage display system, whilst sparing those on the phage capsid. Here, we report the development of a cyclopropenone-based proximity-driven chemical linker that can efficiently cyclize synthetic peptides and peptides fused to a phage-coat protein, and cyclize phage-displayed peptides in a site-specific manner, with no disruption to phage infectivity. Our cyclization strategy enables the construction of stable, highly diverse phage display libraries. These libraries can be used for the selection of high-affinity cyclic peptide binders, as exemplified through model selections on streptavidin and the therapeutic target αvß3.
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Biblioteca de Péptidos , Péptidos Cíclicos , Ciclización , Péptidos Cíclicos/química , Péptidos Cíclicos/metabolismo , Estreptavidina/química , Estreptavidina/metabolismo , Humanos , Proteínas de la Cápside/química , Proteínas de la Cápside/metabolismo , Proteínas de la Cápside/genética , Cisteína/química , Cisteína/metabolismo , Ciclopropanos/química , Péptidos/química , Péptidos/metabolismoRESUMEN
Evolution can occur over ecological timescales, suggesting a potentially important role for rapid evolution in shaping community trait distributions. However, evidence of concordant eco-evolutionary dynamics often comes from in vitro studies of highly simplified communities, and measures of ecological and evolutionary dynamics are rarely directly comparable. Here, we quantified how ecological species sorting and rapid evolution simultaneously shape community trait distributions by tracking within- and between-species changes in a key trait in a complex bacterial community. We focused on the production of siderophores; bacteria use these costly secreted metabolites to scavenge poorly soluble iron and to detoxify environments polluted with toxic nonferrous metals. We found that responses to copper-imposed selection within and between species were ultimately the same-intermediate siderophore levels were favored-and occurred over similar timescales. Despite being a social trait, this level of siderophore production was selected regardless of whether species evolved in isolation or in a community context. Our study suggests that evolutionary selection can play a pivotal role in shaping community trait distributions within natural, highly complex, bacterial communities. Furthermore, trait evolution may not always be qualitatively affected by interactions with other community members.
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Bacterias , Evolución Biológica , Selección Genética , Sideróforos , Sideróforos/metabolismo , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación , Ecosistema , Cobre/metabolismo , Hierro/metabolismoRESUMEN
Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis, and chronic obstructive pulmonary disease. Prolonged infection allows the accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonizing upper airway environments. Here, we model this process using an experimental evolution approach. Pseudomonas aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments-sinus and lungs, under CF and non-CF conditions-selected for loss of twitching motility, increased resistance to multiple antibiotic classes, and a hyper-biofilm phenotype. These traits conferred increased airway colonization potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching, and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included the loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.
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Adaptación Fisiológica , Biopelículas , Infecciones por Pseudomonas , Pseudomonas aeruginosa , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/fisiología , Pseudomonas aeruginosa/metabolismo , Infecciones por Pseudomonas/microbiología , Biopelículas/crecimiento & desarrollo , Animales , Pulmón/microbiología , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/metabolismo , Sistemas de Mensajero Secundario , Fibrosis Quística/microbiología , Ratones , Humanos , Antibacterianos/farmacología , GMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , Mutación , FenotipoRESUMEN
Ecological dependencies - where organisms rely on other organisms for survival - are a ubiquitous feature of life on earth. Multicellular hosts rely on symbionts to provide essential vitamins and amino acids. Legume plants similarly rely on nitrogen-fixing rhizobia to convert atmospheric nitrogen to ammonia. In some cases, dependencies can arise via loss-of-function mutations that allow one partner to benefit from the actions of another. It is common in microbiology to label ecological dependencies between species as cooperation - making it necessary to invoke cooperation-specific frameworks to explain the phenomenon. However, in many cases, such traits are not (at least initially) cooperative, because they are not selected for because of the benefits they confer on a partner species. In contrast, dependencies in microbial communities may originate from fitness benefits gained from genomic-streamlining (i.e. Black Queen Dynamics). Here, we outline how the Black Queen Hypothesis predicts the formation of metabolic dependencies via loss-of-function mutations in microbial communities, without needing to invoke any cooperation-specific explanations. Furthermore we outline how the Black Queen Hypothesis can act as a blueprint for true cooperation as well as discuss key outstanding questions in the field. The nature of interactions in microbial communities can predict the ability of natural communities to withstand and recover from disturbances. Hence, it is vital to gain a deeper understanding of the factors driving these dynamic interactions over evolutionary time.
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Ilusiones , Microbiota , Humanos , Aminoácidos , Evolución Biológica , NitrógenoRESUMEN
A major impediment to the characterization of mtDNA repair mechanisms in comparison to nuclear DNA repair mechanisms is the difficulty of specifically addressing mitochondrial damage. Using a mitochondria-penetrating peptide, we can deliver DNA-damaging agents directly to mitochondria, bypassing the nuclear compartment. Here, we describe the use of an mtDNA-damaging agent in tandem with CRISPR/Cas9 screening for the genome-wide discovery of factors essential for mtDNA damage response. Using mitochondria-targeted doxorubicin (mtDox), we generate mtDNA double-strand breaks (mtDSBs) specifically in this organelle. Combined with an untargeted doxorubicin (Dox) screen, we identify genes with significantly greater essentiality during mitochondrial versus nuclear DNA damage. We characterize the essentiality of our top hit, WRNIP1âobserved here for the first time to respond to mtDNA damage. We further investigate the mitochondrial role of WRNIP1 in innate immune signaling and nuclear genome maintenance, outlining a model that experimentally supports mitochondrial turnover in response to mtDSBs.
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ADN Mitocondrial , Mitocondrias , ADN Mitocondrial/genética , Mitocondrias/genética , Reparación del ADN , Daño del ADN , DoxorrubicinaRESUMEN
FBXW7 is a commonly mutated tumor suppressor gene that functions to regulate numerous oncogenes involved in cell-cycle regulation. Genome-wide CRISPR fitness screens identified a signature of DNA repair and DNA damage response genes as required for the growth of FBXW7-knockout cells. Guided by these findings, we show that FBXW7-mutant cells have high levels of replication stress, which results in a genotype-specific vulnerability to inhibition of the ATR signaling pathway, as these mutant cells become heavily reliant on a robust S-G2 checkpoint. ATR inhibition induces an accelerated S-phase, leading to mitotic catastrophe and cell death caused by the high replication stress present in FBXW7-/- cells. In addition, we provide evidence in cell and organoid studies, and mining of publicly available high-throughput drug screening efforts, that this genotype-specific vulnerability extends to multiple types of cancer, providing a rational means of identifying responsive patients for targeted therapy. SIGNIFICANCE: We have elucidated the synthetic lethal interactions between FBXW7 mutation and DNA damage response genes, and highlighted the potential of ATR inhibitors as targeted therapies for cancers harboring FBXW7 alterations.
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Reparación del ADN , Neoplasias , Humanos , Proteína 7 que Contiene Repeticiones F-Box-WD/genética , Proteínas de la Ataxia Telangiectasia Mutada/genética , Mutación , Neoplasias/genética , Muerte CelularRESUMEN
A major impediment to the characterization of mtDNA repair mechanisms, in comparison to nuclear DNA repair mechanisms, is the difficulty of specifically addressing mitochondrial damage. Using a mitochondria-penetrating peptide, we can deliver DNA-damaging agents directly to mitochondria, bypassing the nuclear compartment. Here, we describe the use of a mtDNA-damaging agent in tandem with CRISPR/Cas9 screening for the genome-wide discovery of factors essential for mtDNA damage response. Using mitochondria-targeted doxorubicin (mtDox) we generate mtDNA double-strand breaks (mtDSBs) specifically in this organelle. Combined with an untargeted Dox screen, we identify genes with significantly greater essentiality during mitochondrial versus nuclear DNA damage. We characterize the essentially of our top hit - WRNIP1 - observed here for the first time to respond to mtDNA damage. We further investigate the mitochondrial role of WRNIP1 in innate immune signaling and nuclear genome maintenance, outlining a model that experimentally supports mitochondrial turnover in response to mtDSBs.
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Publishing in Science, Girish and colleagues achieve chromosome-level genome editing to reveal a requirement for aneuploidy in breast and melanoma cancers. Authors developed and leveraged ReDACT (restoring disomy in aneuploid cells using CRISPR targeting) to generate isogenic models of aneuploidy and demonstrate that some cancers are addicted to increased copy number of specific chromosome arms.
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Edición Génica , Neoplasias , Humanos , Aneuploidia , Neoplasias/genética , CariotipoRESUMEN
BACKGROUND: Intraspecific public goods are commonly shared within microbial populations, where the benefits of public goods are largely limited to closely related conspecifics. One example is the production of iron-scavenging siderophores that deliver iron to cells via specific cell envelope receptor and transport systems. Intraspecific social exploitation of siderophore producers is common, since non-producers avoid the costs of production but retain the cell envelope machinery for siderophore uptake. However, little is known about how interactions between species (i.e., interspecific interactions) can shape intraspecific public goods exploitation. Here, we predicted that strong competition for iron between species in diverse communities will increase costs of siderophore cooperation, and hence drive intraspecific exploitation. We examined how increasing microbial community species diversity shapes intraspecific social dynamics by monitoring the growth of siderophore producers and non-producers of the plant-growth promoting bacterium Pseudomonas fluorescens, embedded within tree-hole microbial communities ranging from 2 to 15 species. RESULTS: We find, contrary to our prediction, that siderophore production is favoured at higher levels of community species richness, driven by increased likelihood of encountering key species that reduce the growth of siderophore non-producing (but not producing) strains of P. fluorescens. CONCLUSIONS: Our results suggest that maintaining a diverse soil microbiota could partly contribute to the maintenance of siderophore production in natural communities.
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Pseudomonas fluorescens , Sideróforos , Hierro , Transporte Biológico , Membrana CelularRESUMEN
Antimicrobial resistance (AMR) is a growing threat to public health, global food security and animal welfare. Despite efforts in antibiotic stewardship, AMR continues to rise worldwide. Anthropogenic activities, particularly intensive agriculture, play an integral role in the dissemination of AMR genes within natural microbial communities - which current antibiotic stewardship typically overlooks. In this review, we examine the impact of anthropogenically induced temperature fluctuations, increased soil salinity, soil fertility loss, and contaminants such as metals and pesticides on the de novo evolution and dissemination of AMR in the environment. These stressors can select for AMR - even in the absence of antibiotics - via mechanisms such as cross-resistance, co-resistance and co-regulation. Moreover, anthropogenic stressors can prime bacterial physiology against stress, potentially widening the window of opportunity for the de novo evolution of AMR. However, research to date is typically limited to the study of single isolated bacterial species - we lack data on how intensive agricultural practices drive AMR over evolutionary timescales in more complex microbial communities. Furthermore, a multidisciplinary approach to fighting AMR is urgently needed, as it is clear that the drivers of AMR extend far beyond the clinical environment.
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Antibacterianos , Plaguicidas , Animales , Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Agricultura , SueloRESUMEN
INTRODUCTION: Our objective was to compare [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 radioimmunotherapy (RIT) agents for decreasing the clonogenic survival fraction (SF) in vitro of EGFR-positive human pancreatic ductal adenocarcinoma (PDAC) cell lines and estimate the relative biological effectiveness (RBE) vs. γ-radiation (XRT). METHODS: EGFR-positive PDAC cell lines (AsPC-1, PANC-1, MIAPaCa-2, Capan-1) and EGFR-knockout PANC-1 EGFR KO cells were treated in vitro for 18 h with (0-19.65 MBq; 72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 or XRT (0-8 Gy) followed by clonogenic assay. The SF was determined after culturing single treated cells for 14 d. Cell fractionation studies were performed for cells incubated with 1 MBq (72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 for 1, 4, or 24 h to estimate the time-integrated activity (Ã) on the cell surface, cytoplasm, nucleus and medium. Radiation absorbed doses in the nucleus were calculated by multiplying à by S-factors calculated by Monte Carlo N Particle (MCNP) modeling using monolayer cell culture geometry. The SF of PDAC cells was plotted vs. dose and fitted to a linear quadratic model to estimate the dose required to decrease the SF to 0.1 (D10). The D10 for RIT agents were compared to XRT to estimate the RBE. DNA double-strand breaks (DSBs) caused by [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 continuous exposure for 5 h or 20 h were probed by immunofluorescence for γ-H2AX. Relative EGFR expression of PDAC cells was assessed by flow cytometry (scored + to +++) and cell doubling times for untreated cells were determined. RESULTS: The D10 for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 9.1 Gy (PANC-1) to 39.9 Gy (Capan-1). The D10 for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 11.7 Gy (AsPC-1) to 170.8 Gy (Capan-1). The D10 for XRT ranged from 2.5 Gy (Capan-1) to 6.7 Gy (PANC-1 EGFR KO). D10 values were not correlated with EGFR expression over a relatively narrow range (++ to +++) or with cell doubling times. Based on D10 values, PANC-1 EGFR KO cells were 1.6-fold less sensitive than PANC-1 cells to [64Cu]Cu-NOTA-panitumumab F(ab')2 and 1.9-fold less sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2. The RBE for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 0.06 for Capan-1 cells to 0.45 for PANC-1 cells. The RBE for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 0.015 for Capan-1 cells to 0.28 for AsPC-1 cells. DNA DSBs were detected in PDAC cells exposed to [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 but were not correlated with the SF of the cells. CONCLUSIONS: We conclude that at the same dose delivered to the cell nucleus [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 were less radiobiologically effective than XRT for decreasing the SF of human PDAC cells, but [64Cu]Cu-NOTA-panitumumab F(ab')2 was more cytotoxic than [177Lu]Lu-NOTA-panitumumab F(ab')2 except for AsPC-1 cells which were more sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2. ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE: This study demonstrates that higher radiation doses may be required for RIT than XRT to achieve radiobiologically equivalent effects when used to treat PDAC.
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Adenocarcinoma , Receptores ErbB , Humanos , Panitumumab , Efectividad Biológica Relativa , Receptores ErbB/metabolismo , ADN , Línea Celular Tumoral , Neoplasias PancreáticasRESUMEN
This article reports on a study analysing changes in the use of digital technologies and working from home during the COVID-19 crisis and the impact of these changes on the wellbeing of five female university lecturers from Australia and Sweden. Applying collaborative autoethnographical methods, this study employed Weick's sensemaking framework to explore how the academics made sense of these sudden changes. The Positive emotion, Engagement, Relationships, Meaning, and Accomplishment (PERMA) wellbeing framework was also employed to explore the effect of these changes on the academics' wellbeing. Findings from the reflective narratives show that after the initial experiences of stress, each university lecturer was able to adapt and navigate the online teaching environment during the pandemic. However, the time constraints in preparing and adapting to online teaching, and working from home, were experienced by some of the university lecturers as highly stressful and isolating which impacted their sense of wellbeing. Even so, working from home was recognized as a positive experience, providing time for research, hobbies, and time with family. This study addresses a gap in current knowledge by examining the impact of the sudden transition to online teaching and learning had on academic wellbeing as conceptualised through the PERMA framework. In addition, by applying Weick's sensemaking framework, this study provides a unique perspective around how academics made sense of the sudden switch to online teaching and learning during COVID-19.
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Since the recognition that mutations in components of the Wnt-ß-catenin pathway underlie some human cancers, considerable attention has been dedicated to developing therapeutic modalities to block its activity. Despite numerous efforts, no drug directly inhibiting Wnt signaling is currently clinically available. Conversely, activating the Wnt pathway in a specific manner has recently been made possible with new molecules mimicking the activity of Wnt proteins, thus offering new possibilities for controlling tissue stem cell activity and for the rational treatment of various degenerative conditions. We describe the landscape of antibody modalities that modulate the Wnt-ß-catenin pathway, and detail the advances and challenges in both cancer and regenerative medicine drug development.
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Neoplasias , Vía de Señalización Wnt , Humanos , beta Catenina , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismoRESUMEN
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Fibrosis Quística , Infecciones por Pseudomonas , Animales , Medios de Cultivo , Pseudomonas aeruginosa/genética , PulmónRESUMEN
CDK11 is a cyclin-dependent kinase that controls proliferation by regulating transcription, RNA splicing, and the cell cycle. As its activity is increasingly associated with cancer, CDK11 is an attractive target for the development of small-molecule inhibitors. However, the development of CDK11 inhibitors with limited off-target effects against other CDKs poses a challenge based on the high conservation of sequence across family members. OTS964 is notable as it displays a measure of specificity for CDK11 in cells. To understand the basis for OTS964's specificity for CDK11, we solved a 2.6 Å crystal structure of the CDK11 kinase domain bound to OTS964. Despite the absence of cyclin, CDK11 adopts an active-like conformation when bound to OTS964. We identified amino acids likely to contribute to the specificity of OTS964 for CDK11 and assessed their contribution to OTS964 binding by isothermal titration calorimetry (ITC) in vitro and by resistance to OTS964 in cells.
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Quinasas Ciclina-Dependientes , Quinolonas , Quinasas Ciclina-Dependientes/genética , Quinasas Ciclina-Dependientes/metabolismo , Fosforilación , Ciclo CelularRESUMEN
FBXW7, which encodes a substrate-specific receptor of an SCF E3 ligase complex, is a frequently mutated human tumor suppressor gene known to regulate the post-translational stability of various proteins involved in cellular proliferation. Here, using genome-wide CRISPR screens, we report a novel synthetic lethal genetic interaction between FBXW7 and CCNL1 and describe CCNL1 as a new substrate of the SCF-FBXW7 E3 ligase. Further analysis showed that the CCNL1-CDK11 complex is critical at the G2-M phase of the cell cycle since defective CCNL1 accumulation, resulting from FBXW7 mutation, leads to shorter mitotic time. Cells harboring FBXW7 loss-of-function mutations are hypersensitive to treatment with a CDK11 inhibitor, highlighting a genetic vulnerability that could be leveraged for cancer treatment.
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Ciclinas , Proteína 7 que Contiene Repeticiones F-Box-WD , Ubiquitina-Proteína Ligasas , Humanos , Proteína 7 que Contiene Repeticiones F-Box-WD/genética , Mutación , Ubiquitina-Proteína Ligasas/genética , Ciclinas/metabolismo , UbiquitinaciónRESUMEN
OBJECTIVE: Obesity-linked type 2 diabetes (T2D) is a worldwide health concern and many novel approaches are being considered for its treatment and subsequent prevention of serious comorbidities. Co-administration of glucagon like peptide 1 (GLP-1) and peptide YY3-36 (PYY3-36) renders a synergistic decrease in energy intake in obese men. However, mechanistic details of the synergy between these peptide agonists and their effects on metabolic homeostasis remain relatively scarce. METHODS: In this study, we utilized long-acting analogues of GLP-1 and PYY3-36 (via Fc-peptide conjugation) to better characterize the synergistic pharmacological benefits of their co-administration on body weight and glycaemic regulation in obese and diabetic mouse models. Hyperinsulinemic-euglycemic clamps were used to measure weight-independent effects of Fc-PYY3-36 + Fc-GLP-1 on insulin action. Fluorescent light sheet microscopy analysis of whole brain was performed to assess activation of brain regions. RESULTS: Co-administration of long-acting Fc-IgG/peptide conjugates of Fc-GLP-1 and Fc-PYY3-36 (specific for PYY receptor-2 (Y2R)) resulted in profound weight loss, restored glucose homeostasis, and recovered endogenous ß-cell function in two mouse models of obese T2D. Hyperinsulinemic-euglycemic clamps in C57BLKS/J db/db and diet-induced obese Y2R-deficient (Y2RKO) mice indicated Y2R is required for a weight-independent improvement in peripheral insulin sensitivity and enhanced hepatic glycogenesis. Brain cFos staining demonstrated distinct temporal activation of regions of the hypothalamus and hindbrain following Fc-PYY3-36 + Fc-GLP-1R agonist administration. CONCLUSIONS: These results reveal a therapeutic approach for obesity/T2D that improved insulin sensitivity and restored endogenous ß-cell function. These data also highlight the potential association between the gut-brain axis in control of metabolic homeostasis.
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Péptido 1 Similar al Glucagón/metabolismo , Obesidad/metabolismo , Péptido YY/metabolismo , Animales , Glucemia/metabolismo , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Dieta , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Energía/efectos de los fármacos , Metabolismo Energético/efectos de los fármacos , Derivación Gástrica , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Hipotálamo , Resistencia a la Insulina/fisiología , Células Secretoras de Insulina/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/fisiopatología , Péptido YY/fisiología , Pérdida de PesoRESUMEN
BACKGROUND AND OBJECTIVES: Slowing the spread of antimicrobial resistance is urgent if we are to continue treating infectious diseases successfully. There is increasing evidence microbial interactions between and within species are significant drivers of resistance. On one hand, cross-protection by resistant genotypes can shelter susceptible microbes from the adverse effects of antibiotics, reducing the advantage of resistance. On the other hand, antibiotic-mediated killing of susceptible genotypes can alleviate competition and allow resistant strains to thrive (competitive release). Here, by observing interactions both within and between species in microbial communities sampled from humans, we investigate the potential role for cross-protection and competitive release in driving the spread of ampicillin resistance in the ubiquitous gut commensal and opportunistic pathogen Escherichia coli. METHODOLOGY: Using anaerobic gut microcosms comprising E.coli embedded within gut microbiota sampled from humans, we tested for cross-protection and competitive release both within and between species in response to the clinically important beta-lactam antibiotic ampicillin. RESULTS: While cross-protection gave an advantage to antibiotic-susceptible E.coli in standard laboratory conditions (well-mixed LB medium), competitive release instead drove the spread of antibiotic-resistant E.coli in gut microcosms (ampicillin boosted growth of resistant bacteria in the presence of susceptible strains). CONCLUSIONS AND IMPLICATIONS: Competition between resistant strains and other members of the gut microbiota can restrict the spread of ampicillin resistance. If antibiotic therapy alleviates competition with resident microbes by killing susceptible strains, as here, microbiota-based interventions that restore competition could be a key for slowing the spread of resistance. LAY SUMMARY: Slowing the spread of global antibiotic resistance is an urgent task. In this paper, we ask how interactions between microbial species drive the spread of resistance. We show that antibiotic killing of susceptible microbes can free up resources for resistant microbes and allow them to thrive. Therefore, we should consider microbes in light of their social interactions to understand the spread of resistance.
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BACKGROUND: People who become homeless have higher morbidity and mortality, use a disproportionate amount of healthcare resources, and generate a large volume of potentially preventable healthcare and other costs compared to more privileged individuals. Although access to rehabilitation is a human right under article 26 of the United Nations Convention on the Rights of Persons with Disabilities, the rehabilitation needs of individuals with homelessness have not been explored, and this project's purpose was to establish a baseline of need for this cohort. METHODS: A prospective audit of case discussions at an inclusion health service over a 2-month period in 2018. RESULTS: Four multidisciplinary inclusion health clinics were observed with over 20 cases discussed in each and data were extracted using a bespoke audit data extraction tool. The inclusion health needs were diverse and complex with many unmet rehabilitation needs. Physical and cognitive rehabilitation needs were identified in over 50% of cases discussed. Musculoskeletal problems and acquired brain injuries were the most common cause of activity limitation. Most had concurrent medical conditions and addiction and/or mental health needs. None had access to rehabilitation services. CONCLUSION: The results of this study show that the rehabilitative needs of this cohort are significant and are not being met through traditional models of care. We are currently exploring innovative ways to provide appropriate services to these individuals.
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Prestación Integrada de Atención de Salud , Personas con Mala Vivienda , Adulto , Accesibilidad a los Servicios de Salud , Necesidades y Demandas de Servicios de Salud , Humanos , Irlanda/epidemiología , Salud MentalRESUMEN
Ecological theory predicts interactions between species to become more positive under abiotic stress, while competition should prevail in more benign environments. However, experimental tests of this stress gradient hypothesis in natural microbial communities are lacking. We test this hypothesis by measuring interactions between 10 different members of a bacterial community inhabiting potting compost in the presence or absence of toxic copper stress. We found that copper stress caused significant net changes in species interaction signs, shifting the net balance towards more positive interactions. This pattern was at least in part driven by copper-sensitive isolates - that produced relatively small amounts of metal-detoxifying siderophores - benefitting from the presence of other species that produce extracellular detoxifying agents. As well as providing support for the stress gradient hypothesis, our results highlight the importance of community-wide public goods in shaping microbial community composition.