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1.
Elife ; 122023 Jul 06.
Article in English | MEDLINE | ID: mdl-37410076

ABSTRACT

Many bacteria use quorum sensing to control changes in lifestyle. The process is regulated by microbially derived 'autoinducer' signalling molecules, that accumulate in the local environment. Individual cells sense autoinducer abundance, to infer population density, and alter their behaviour accordingly. In Vibrio cholerae, quorum-sensing signals are transduced by phosphorelay to the transcription factor LuxO. Unphosphorylated LuxO permits expression of HapR, which alters global gene expression patterns. In this work, we have mapped the genome-wide distribution of LuxO and HapR in V. cholerae. Whilst LuxO has a small regulon, HapR targets 32 loci. Many HapR targets coincide with sites for the cAMP receptor protein (CRP) that regulates the transcriptional response to carbon starvation. This overlap, also evident in other Vibrio species, results from similarities in the DNA sequence bound by each factor. At shared sites, HapR and CRP simultaneously contact the double helix and binding is stabilised by direct interaction of the two factors. Importantly, this involves a CRP surface that usually contacts RNA polymerase to stimulate transcription. As a result, HapR can block transcription activation by CRP. Thus, by interacting at shared sites, HapR and CRP integrate information from quorum sensing and cAMP signalling to control gene expression. This likely allows V. cholerae to regulate subsets of genes during the transition between aquatic environments and the human host.


Subject(s)
Vibrio cholerae , Humans , Vibrio cholerae/physiology , Quorum Sensing/genetics , Repressor Proteins/metabolism , Bacterial Proteins/metabolism , Transcription Factors/genetics , Transcription Factors/metabolism , Cyclic AMP Receptor Protein/genetics , Cyclic AMP Receptor Protein/metabolism , Gene Expression Regulation, Bacterial
2.
Microbiology (Reading) ; 169(5)2023 05.
Article in English | MEDLINE | ID: mdl-37204124

ABSTRACT

The closely related transcription factors MarA, SoxS, Rob and RamA control overlapping stress responses in many enteric bacteria. Furthermore, constitutive expression of such regulators is linked to clinical antibiotic resistance. In this work we have mapped the binding of MarA, SoxS, Rob and RamA across the Salmonella Typhimurium genome. In parallel, we have monitored changes in transcription start site use resulting from expression of the regulators. Together, these data allow direct and indirect gene regulatory effects to be disentangled. Promoter architecture across the regulon can also be deduced. At a phylogenetic scale, around one third of regulatory targets are conserved in most organisms encoding MarA, SoxS, Rob or RamA. We focused our attention on the control of csgD, which encodes a transcriptional activator responsible for stimulating production of curli fibres during biofilm formation. We show that expression of csgD is particularly sensitive to SoxS that binds upstream to repress transcription. This differs to the situation in Escherichia coli, where MarA regulates csgD indirectly.


Subject(s)
DNA-Binding Proteins , Escherichia coli Proteins , DNA-Binding Proteins/metabolism , Trans-Activators/genetics , Trans-Activators/metabolism , Salmonella typhimurium/genetics , Salmonella typhimurium/metabolism , Escherichia coli Proteins/genetics , Regulon , Phylogeny , Gene Expression Regulation, Bacterial , Transcription Factors/genetics , Transcription Factors/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Biofilms , Bacterial Proteins/genetics , Bacterial Proteins/metabolism
3.
Microbiology (Reading) ; 169(5)2023 05.
Article in English | MEDLINE | ID: mdl-37204130

ABSTRACT

Transcription of the DNA template, to generate an RNA message, is the first step in gene expression. The process initiates at DNA sequences called promoters. Conventionally, promoters have been considered to drive transcription in a specific direction. However, in recent work, we showed that many prokaryotic promoters can drive divergent transcription. This is a consequence of key DNA sequences for transcription initiation being inherently symmetrical. Here, we used global transcription start site mapping to determine the prevalence of such bidirectional promoters in Salmonella Typhimurium. Surprisingly, bidirectional promoters occur three times more frequently in plasmid components of the genome compared to chromosomal DNA. Implications for the evolution of promoter sequences are discussed.


Subject(s)
Plasmids , Promoter Regions, Genetic , Salmonella typhimurium , Plasmids/genetics , Promoter Regions, Genetic/genetics , Salmonella typhimurium/genetics , Transcription, Genetic/genetics , Transcription Initiation Site , Genome, Bacterial/genetics , Chromosomes, Bacterial/genetics
4.
bioRxiv ; 2023 May 26.
Article in English | MEDLINE | ID: mdl-36798193

ABSTRACT

Many bacteria use quorum sensing to control changes in lifestyle. The process is regulated by microbially derived "autoinducer" signalling molecules, that accumulate in the local environment. Individual cells sense autoinducer abundance, to infer population density, and alter their behaviour accordingly. In Vibrio cholerae , quorum sensing signals are transduced by phosphorelay to the transcription factor LuxO. Unphosphorylated LuxO permits expression of HapR, which alters global gene expression patterns. In this work, we have mapped the genome-wide distribution of LuxO and HapR in V. cholerae . Whilst LuxO has a small regulon, HapR targets 32 loci. Many HapR targets coincide with sites for the cAMP receptor protein (CRP) that regulates the transcriptional response to carbon starvation. This overlap, also evident in other Vibrio species, results from similarities in the DNA sequence bound by each factor. At shared sites, HapR and CRP simultaneously contact the double helix and binding is stabilised by direct interaction of the two factors. Importantly, this involves a CRP surface that usually contacts RNA polymerase to stimulate transcription. As a result, HapR can block transcription activation by CRP. Thus, by interacting at shared sites, HapR and CRP integrate information from quorum sensing and cAMP signalling to control gene expression. This likely allows V. cholerae to regulate subsets of genes during the transition between aquatic environments and the human host.

5.
mBio ; 13(3): e0095222, 2022 06 28.
Article in English | MEDLINE | ID: mdl-35583320

ABSTRACT

Bacterial cells and their associated plasmids and bacteriophages encode numerous small proteins of unknown function. One example, the 73-amino-acid protein TraR, is encoded by the transfer operon of the conjugative F plasmid of Escherichia coli. TraR is a distant homolog of DksA, a protein found in almost all proteobacterial species that is required for ppGpp to regulate transcription during the stringent response. TraR and DksA increase or decrease transcription initiation depending on the kinetic features of the promoter by binding directly to RNA polymerase without binding to DNA. Unlike DksA, whose full activity requires ppGpp as a cofactor, TraR is fully active by itself and unaffected by ppGpp. TraR belongs to a family of divergent proteins encoded by proteobacterial bacteriophages and other mobile elements. Here, we experimentally addressed whether other members of the TraR family function like the F element-encoded TraR. Purified TraR and all 5 homologs that were examined bound to RNA polymerase, functioned at lower concentrations than DksA, and complemented a dksA-null strain for growth on minimal medium. One of the homologs, λ Orf73, encoded by bacteriophage lambda, was examined in greater detail. λ Orf73 slowed host growth and increased phage burst size. Mutational analysis suggested that λ Orf73 and TraR have a similar mechanism for inhibiting rRNA and r-protein promoters. We suggest that TraR and its homologs regulate host transcription to divert cellular resources to phage propagation or conjugation without induction of ppGpp and a stringent response. IMPORTANCE TraR is a distant homolog of the transcription factor DksA and the founding member of a large family of small proteins encoded by proteobacterial phages and conjugative plasmids. Reprogramming transcription during the stringent response requires the interaction of DksA not only with RNA polymerase but also with the stress-induced regulatory nucleotide ppGpp. We show here that five phage TraR homologs by themselves, without ppGpp, regulate transcription of host promoters, mimicking the effects of DksA and ppGpp together. During a stringent response, ppGpp independently binds directly to, and inhibits the activities of, many proteins in addition to RNA polymerase, including translation factors, enzymes needed for ribonucleotide biosynthesis, and other metabolic enzymes. Here, we suggest a physiological role for TraR-like proteins: bacteriophages utilize TraR homologs to reprogram host transcription in the absence of ppGpp induction and thus without inhibiting host enzymes needed for phage development.


Subject(s)
Escherichia coli Proteins , Escherichia coli , Bacteriophage lambda/genetics , DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Escherichia coli Proteins/metabolism , Gene Expression Regulation, Bacterial , Guanosine Tetraphosphate/metabolism , Transcription Factors/metabolism , Transcription, Genetic
6.
JAMA Cardiol ; 7(5): 513-520, 2022 05 01.
Article in English | MEDLINE | ID: mdl-35385057

ABSTRACT

Importance: Low-flow severe aortic stenosis (AS) has higher mortality than severe AS with normal flow. The conventional definition of low-flow AS is an indexed stroke volume (SVi) by echocardiography less than 35 mL/m2. Cardiovascular magnetic resonance (CMR) is the reference standard for quantifying left ventricular volumes and function from which SVi by CMR can be derived. Objective: To determine the association of left ventricular SVi by CMR with myocardial remodeling and survival among patients with severe AS after valve replacement. Design, Setting, and Participants: This multicenter longitudinal cohort study was conducted between January 2003 and May 2015 across 6 UK cardiothoracic centers. Patients with severe AS listed for either surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR) were included. Patients underwent preprocedural echocardiography and CMR. Patients were stratified by echocardiography-derived aortic valve mean and/or peak gradient and SVi by CMR into 4 AS endotypes: low-flow, low-gradient AS; low-flow, high-gradient AS; normal-flow, low-gradient AS; and normal-flow, high-gradient AS. Patients were observed for a median of 3.6 years. Data were analyzed from September to November 2021. Exposures: SAVR or TAVR. Main Outcomes and Measures: All-cause and cardiovascular (CV) mortality after aortic valve intervention. Results: Of 674 included patients, 425 (63.1%) were male, and the median (IQR) age was 75 (66-80) years. The median (IQR) aortic valve area index was 0.4 (0.3-0.4) cm2/m2. Patients with low-flow AS endotypes (low gradient and high gradient) had lower left ventricular ejection fraction, mass, and wall thickness and increased all-cause and CV mortality than patients with normal-flow AS (all-cause mortality: hazard ratio [HR], 2.08; 95% CI, 1.37-3.14; P < .001; CV mortality: HR, 3.06; 95% CI, 1.79-5.25; P < .001). CV mortality was independently associated with lower SVi (HR, 1.64; 95% CI, 1.08-2.50; P = .04), age (HR, 2.54; 95% CI, 1.29-5.01; P = .001), and higher quantity of late gadolinium enhancement (HR, 2.93; 95% CI, 1.68-5.09; P < .001). CV mortality hazard increased more rapidly in those with an SVI less than 45 mL/m2. SVi by CMR was independently associated with age, atrial fibrillation, focal scar (by late gadolinium enhancement), and parameters of cardiac remodeling (left ventricular mass and left atrial volume). Conclusions and Relevance: In this cohort study, SVi by CMR was associated with CV mortality after aortic valve replacement, independent of age, focal scar, and ejection fraction. The unique capability of CMR to quantify myocardial scar, combined with other prognostically important imaging biomarkers, such as SVi by CMR, may enable comprehensive stratification of postoperative risk in patients with severe symptomatic AS.


Subject(s)
Aortic Valve Stenosis , Aged , Aged, 80 and over , Aortic Valve Stenosis/diagnostic imaging , Aortic Valve Stenosis/surgery , Cicatrix/pathology , Cohort Studies , Contrast Media , Female , Fibrosis , Gadolinium , Humans , Longitudinal Studies , Magnetic Resonance Spectroscopy , Male , Stroke Volume , Ventricular Function, Left
7.
Nucleic Acids Res ; 50(1): 149-159, 2022 01 11.
Article in English | MEDLINE | ID: mdl-34908143

ABSTRACT

Many bacteria use cyclic dimeric guanosine monophosphate (c-di-GMP) to control changes in lifestyle. The molecule, synthesized by proteins having diguanylate cyclase activity, is often a signal to transition from motile to sedentary behaviour. In Vibrio cholerae, c-di-GMP can exert its effects via the transcription factors VpsT and VpsR. Together, these proteins activate genes needed for V. cholerae to form biofilms. In this work, we have mapped the genome-wide distribution of VpsT in a search for further regulatory roles. We show that VpsT binds 23 loci and recognises a degenerate DNA palindrome having the consensus 5'-W-5R-4[CG]-3Y-2W-1W+1R+2[GC]+3Y+4W+5-3'. Most genes targeted by VpsT encode functions related to motility, biofilm formation, or c-di-GMP metabolism. Most notably, VpsT activates expression of the vpvABC operon that encodes a diguanylate cyclase. This creates a positive feedback loop needed to maintain intracellular levels of c-di-GMP. Mutation of the key VpsT binding site, upstream of vpvABC, severs the loop and c-di-GMP levels fall accordingly. Hence, as well as relaying the c-di-GMP signal, VpsT impacts c-di-GMP homeostasis.


Subject(s)
Bacterial Proteins/metabolism , Cyclic GMP/analogs & derivatives , Regulatory Sequences, Nucleic Acid , Transcription Factors/metabolism , Vibrio cholerae/genetics , Cyclic GMP/metabolism , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Homeostasis , Operon , Phosphorus-Oxygen Lyases/genetics , Phosphorus-Oxygen Lyases/metabolism , Protein Binding , Vibrio cholerae/metabolism
8.
J Med Chem ; 64(15): 10742-10771, 2021 08 12.
Article in English | MEDLINE | ID: mdl-34232650

ABSTRACT

Domain-specific BET bromodomain ligands represent an attractive target for drug discovery with the potential to unlock the therapeutic benefits of antagonizing these proteins without eliciting the toxicological aspects seen with pan-BET inhibitors. While we have reported several distinct classes of BD2 selective compounds, namely, GSK620, GSK549, and GSK046, only GSK046 shows high aqueous solubility. Herein, we describe the lead optimization of a further class of highly soluble compounds based upon a picolinamide chemotype. Focusing on achieving >1000-fold selectivity for BD2 over BD1 ,while retaining favorable physical chemical properties, compound 36 was identified as being 2000-fold selective for BD2 over BD1 (Brd4 data) with >1 mg/mL solubility in FaSSIF media. 36 represents a valuable new in vivo ready molecule for the exploration of the BD2 phenotype.


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Pyridines/pharmacology , Transcription Factors/antagonists & inhibitors , Cell Cycle Proteins/metabolism , Dose-Response Relationship, Drug , Humans , Models, Molecular , Molecular Structure , Pyridines/chemistry , Structure-Activity Relationship , Transcription Factors/metabolism
9.
J Med Chem ; 64(15): 10772-10805, 2021 08 12.
Article in English | MEDLINE | ID: mdl-34255512

ABSTRACT

The profound efficacy of pan-BET inhibitors is well documented, but these epigenetic agents have shown pharmacology-driven toxicity in oncology clinical trials. The opportunity to identify inhibitors with an improved safety profile by selective targeting of a subset of the eight bromodomains of the BET family has triggered extensive medicinal chemistry efforts. In this article, we disclose the identification of potent and selective drug-like pan-BD2 inhibitors such as pyrazole 23 (GSK809) and furan 24 (GSK743) that were derived from the pyrrole fragment 6. We transpose the key learnings from a previous pyridone series (GSK620 2 as a representative example) to this novel class of inhibitors, which are characterized by significantly improved solubility relative to our previous research.


Subject(s)
Furans/pharmacology , Proteins/antagonists & inhibitors , Pyrazoles/pharmacology , Dose-Response Relationship, Drug , Furans/chemistry , Humans , Molecular Structure , Proteins/metabolism , Pyrazoles/chemistry , Structure-Activity Relationship
10.
J Med Chem ; 64(15): 10806-10833, 2021 08 12.
Article in English | MEDLINE | ID: mdl-34251219

ABSTRACT

Second-generation bromodomain and extra terminal (BET) inhibitors, which selectively target one of the two bromodomains in the BET proteins, have begun to emerge in the literature. These inhibitors aim to help determine the roles and functions of each domain and assess whether they can demonstrate an improved safety profile in clinical settings compared to pan-BET inhibitors. Herein, we describe the discovery of a novel BET BD2-selective chemotype using a structure-based drug design from a hit identified by DNA-encoded library technologies, showing a structural differentiation from key previously reported greater than 100-fold BD2-selective chemotypes GSK620, GSK046, and ABBV-744. Following a structure-based hypothesis for the selectivity and optimization of the physicochemical properties of the series, we identified 60 (GSK040), an in vitro ready and in vivo capable BET BD2-inhibitor of unprecedented selectivity (5000-fold) against BET BD1, excellent selectivity against other bromodomains, and good physicochemical properties. This novel chemical probe can be added to the toolbox used in the advancement of epigenetics research.


Subject(s)
DNA/chemistry , Drug Discovery , Proteins/antagonists & inhibitors , Small Molecule Libraries/pharmacology , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Humans , Molecular Structure , Protein Domains/drug effects , Proteins/metabolism , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Structure-Activity Relationship
11.
J Med Chem ; 64(6): 3249-3281, 2021 03 25.
Article in English | MEDLINE | ID: mdl-33662213

ABSTRACT

A number of reports have recently been published describing the discovery and optimization of bromo and extraterminal inhibitors which are selective for the second bromodomain (BD2); these include our own work toward GSK046 (3) and GSK620 (5). This paper describes our approach to mitigating the genotoxicity risk of GSK046 by replacement of the acetamide functionality with a heterocyclic ring. This was followed by a template-hopping and hybridization approach, guided by structure-based drug design, to incorporate learnings from other BD2-selective series, optimize the vector for the amide region, and explore the ZA cleft, leading to the identification of potent, selective, and bioavailable compounds 28 (GSK452), 39 (GSK737), and 36 (GSK217).


Subject(s)
Cell Cycle Proteins/antagonists & inhibitors , Protein Domains/drug effects , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Transcription Factors/antagonists & inhibitors , Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolism , Drug Design , Drug Discovery , Humans , Transcription Factors/chemistry , Transcription Factors/metabolism
12.
Osteoarthritis Cartilage ; 29(6): 802-814, 2021 06.
Article in English | MEDLINE | ID: mdl-33621705

ABSTRACT

OBJECTIVES: Pain is the prevailing symptom of knee osteoarthritis. Central sensitisation creates discordance between pain and joint pathology. We previously reported a Central Pain Mechanisms trait derived from eight discrete characteristics: Neuropathic-like pain, Fatigue, Cognitive-impact, Catastrophising, Anxiety, Sleep disturbance, Depression, and Pain distribution. We here validate and show that an 8-item questionnaire, Central Aspects of Pain in the Knee (CAP-Knee) is associated both with sensory- and affective- components of knee pain severity. METHODS: Participants with knee pain were recruited from the Investigating Musculoskeletal Health and Wellbeing study in the East Midlands, UK. CAP-Knee items were refined following cognitive interviews. Psychometric properties were assessed in 250 participants using Rasch-, and factor-analysis, and Cronbach's alpha. Intra-class correlation coefficients tested repeatability. Associations between CAP-Knee and McGill Pain questionnaire pain severity scores were assessed using linear regression. RESULTS: CAP-Knee targeted the knee pain sample well. Cognitive interviews indicated that participants interpreted CAP-Knee items in diverse ways, which aligned to their intended meanings. Fit to the Rasch model was optimised by rescoring each item, producing a summated score from 0 to 16. Internal consistency was acceptable (Cronbach's alpha = 0.74) and test-retest reliability was excellent (ICC2,1 = 0.91). Each CAP-Knee item contributed uniquely to one discrete 'Central Mechanisms trait' factor. High CAP-Knee scores associated with worse overall knee pain intensity, and with each of sensory- and affective- McGill Pain Questionnaire scores. CONCLUSION: CAP-Knee is a simple and valid self-report questionnaire, which measures a single 'Central Mechanisms' trait, and may help identify and target centrally-acting treatments aiming to reduce the burden of knee pain.


Subject(s)
Arthralgia/diagnosis , Central Nervous System Sensitization , Diagnostic Self Evaluation , Knee Joint , Self Report , Aged , Cross-Sectional Studies , Female , Humans , Male , Middle Aged
13.
J Public Health (Oxf) ; 43(1): e92-e99, 2021 04 12.
Article in English | MEDLINE | ID: mdl-31840739

ABSTRACT

BACKGROUND: Uptake of NHS Health Checks (NHSHCs) is sub-optimal. This study aimed to increase their uptake using behaviourally informed invitation letters. METHOD: Patients registered with 6 general practices in Northamptonshire, England who were eligible for an NHSHC between 10 February 2014 and 31 January 2015 were randomized monthly, using a random number generator, to three trial arms: control (standard invitation), sunk costs (resources already allocated) and counterargument (against common barriers to attendance). The outcome measure was uptake of NHSHC by 12 weeks after 31 January. RESULTS: In total, 6331 patients were randomized. After exclusions, due to ineligibility for the NHSHC, data were analysed for N = 6313 patients: N = 2123 control; N = 2085 counterargument; N = 2105 sunk costs. Overall, 2364 (37.45%) patients attended an NHSHC. Both intervention letters increased uptake compared to control, by 5.46% using counterargument (adjusted odds ratio (AOR) 1.32, CI 1.162-1.51, p < 0.001) and 4.33% using sunk costs (AOR 1.246, CI 1.10-1.42, p < 0.001), with no significant difference between the two. CONCLUSION: Behaviourally informed invitation letters, containing sunk costs or counterargument messages, can improve the uptake of NHSHCs. The trial was registered with the International Standard Randomised Controlled Trial Registration Number Scheme (ISRCTN57110614).


Subject(s)
Cardiovascular Diseases , State Medicine , England , Humans , Primary Health Care
14.
ACS Med Chem Lett ; 11(8): 1581-1587, 2020 Aug 13.
Article in English | MEDLINE | ID: mdl-32832027

ABSTRACT

Pan-BET inhibitors have shown profound efficacy in a number of in vivo preclinical models and have entered the clinic in oncology trials where adverse events have been reported. These inhibitors interact equipotently with the eight bromodomains of the BET family of proteins. To better understand the contribution of each domain to their efficacy and to improve from their safety profile, selective inhibitors are required. This Letter discloses the profile of GSK973, a highly selective inhibitor of the second bromodomains of the BET proteins that has undergone extensive preclinical in vitro and in vivo characterization.

15.
J Med Chem ; 63(17): 9070-9092, 2020 09 10.
Article in English | MEDLINE | ID: mdl-32691591

ABSTRACT

Pan-bromodomain and extra terminal domain (BET) inhibitors interact equipotently with the eight bromodomains of the BET family of proteins and have shown profound efficacy in a number of in vitro phenotypic assays and in vivo pre-clinical models in inflammation or oncology. A number of these inhibitors have progressed to the clinic where pharmacology-driven adverse events have been reported. To better understand the contribution of each domain to their efficacy and improve their safety profile, selective inhibitors are required. This article discloses the profile of GSK046, also known as iBET-BD2, a highly selective inhibitor of the second bromodomains of the BET proteins that has undergone extensive pre-clinical in vitro and in vivo characterization.


Subject(s)
Amides/chemical synthesis , Drug Design , Transcription Factors/antagonists & inhibitors , Amides/chemistry , Amides/metabolism , Animals , Benzene Derivatives/chemistry , Binding Sites , Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/metabolism , Crystallography, X-Ray , Humans , Microsomes, Liver/metabolism , Molecular Dynamics Simulation , Protein Domains , Quantum Theory , Rats , Structure-Activity Relationship , Transcription Factors/metabolism
16.
J Med Chem ; 63(17): 9093-9126, 2020 09 10.
Article in English | MEDLINE | ID: mdl-32702236

ABSTRACT

The profound efficacy, yet associated toxicity of pan-BET inhibitors is well documented. The possibility of an ameliorated safety profile driven by significantly selective (>100-fold) inhibition of a subset of the eight bromodomains is enticing, but challenging given the close homology. Herein, we describe the X-ray crystal structure-directed optimization of a novel weak fragment ligand with a pan-second bromodomain (BD2) bias, to potent and highly BD2 selective inhibitors. A template hopping approach, enabled by our parallel research into an orthogonal template (15, GSK046), was the basis for the high selectivity observed. This culminated in two tool molecules, 20 (GSK620) and 56 (GSK549), which showed an anti-inflammatory phenotype in human whole blood, confirming their cellular target engagement. Excellent broad selectivity, developability, and in vivo oral pharmacokinetics characterize these tools, which we hope will be of broad utility to the field of epigenetics research.


Subject(s)
Anti-Inflammatory Agents/chemistry , Ligands , Transcription Factors/antagonists & inhibitors , Administration, Oral , Amides/chemistry , Amides/metabolism , Amides/pharmacokinetics , Animals , Anti-Inflammatory Agents/metabolism , Anti-Inflammatory Agents/pharmacokinetics , Binding Sites , Cell Cycle Proteins/antagonists & inhibitors , Cell Cycle Proteins/metabolism , Crystallography, X-Ray , Dogs , Half-Life , Humans , Hydrogen Bonding , Male , Molecular Dynamics Simulation , Protein Domains , Rats , Rats, Wistar , Structure-Activity Relationship , Transcription Factors/metabolism
18.
J Am Heart Assoc ; 9(1): e011521, 2020 01 07.
Article in English | MEDLINE | ID: mdl-31852424

ABSTRACT

Background Spironolactone may have prognostic benefit in selected patients with heart failure with preserved ejection fraction. This study assessed the myocardial tissue effects of spironolactone in heart failure with preserved ejection fraction. Methods and Results A 1:1 randomized controlled study of 6 months of spironolactone versus control in heart failure with preserved ejection fraction. The primary outcome was change in myocardial extracellular volume fraction by cardiovascular magnetic resonance as a surrogate of diffuse fibrosis. Of 55 randomized patients, 40 (20 women; age, 75.2±5.9 years) completed follow-up (19 treatment, 21 control). A significant change in extracellular volume over the study period was not seen (treatment, 28.7±3.7% versus 27.7±3.4% [P=0.14]; controls, 27.6±3.4% versus 28.3±4.4% [P=0.14]); however, the rate of extracellular volume expansion was decreased by spironolactone (-1.0±2.4% versus 0.8±2.2%). Indexed left ventricular mass decreased with treatment (104.4±26.6 versus 94.0±20.6 g/m2; P=0.001) but not in controls (101.4±29.4 versus 104.0±32.8 g/m2; P=0.111). Extracellular mass decreased by 13.8% (15.1±4.8 versus 13.0±3.4 g/m2; P=0.003), and cellular mass decreased by 8.3% (37.6±10.0 versus 34.3±7.9 g/m2; P=0.001) with spironolactone, but was static in controls. Conclusions Spironolactone did not lead to significant change in extracellular volume. However, spironolactone did decrease rate of extracellular expansion, with a decrease in the mass of both cellular and extracellular myocardial compartments. These data point to the mechanism of action of spironolactone in heart failure with preserved ejection fraction, including a direct tissue effect with a reduction in rate of myocardial fibrosis.


Subject(s)
Heart Failure/drug therapy , Mineralocorticoid Receptor Antagonists/therapeutic use , Myocardium/pathology , Spironolactone/therapeutic use , Stroke Volume/drug effects , Ventricular Function, Left/drug effects , Ventricular Remodeling/drug effects , Aged , Aged, 80 and over , England , Female , Fibrosis , Heart Failure/diagnostic imaging , Heart Failure/physiopathology , Humans , Magnetic Resonance Imaging, Cine , Male , Time Factors , Treatment Outcome
19.
PLoS Genet ; 15(10): e1008362, 2019 10.
Article in English | MEDLINE | ID: mdl-31658256

ABSTRACT

Many bacteria use population density to control gene expression via quorum sensing. In Vibrio cholerae, quorum sensing coordinates virulence, biofilm formation, and DNA uptake by natural competence. The transcription factors AphA and HapR, expressed at low and high cell density respectively, play a key role. In particular, AphA triggers the entire virulence cascade upon host colonisation. In this work we have mapped genome-wide DNA binding by AphA. We show that AphA is versatile, exhibiting distinct modes of DNA binding and promoter regulation. Unexpectedly, whilst HapR is known to induce natural competence, we demonstrate that AphA also intervenes. Most notably, AphA is a direct repressor of tfoX, the master activator of competence. Hence, production of AphA markedly suppressed DNA uptake; an effect largely circumvented by ectopic expression of tfoX. Our observations suggest dual regulation of competence. At low cell density AphA is a master repressor whilst HapR activates the process at high cell density. Thus, we provide deep mechanistic insight into the role of AphA and highlight how V. cholerae utilises this regulator for diverse purposes.


Subject(s)
Cholera/genetics , DNA-Binding Proteins/genetics , Trans-Activators/genetics , Vibrio cholerae/genetics , Biofilms/growth & development , Cholera/microbiology , Gene Expression Regulation, Bacterial/genetics , Host-Pathogen Interactions/genetics , Humans , Promoter Regions, Genetic/genetics , Quorum Sensing/genetics , Transcription Factors/genetics , Vibrio cholerae/pathogenicity
20.
BMJ Open ; 9(1): e022329, 2019 01 21.
Article in English | MEDLINE | ID: mdl-30670503

ABSTRACT

OBJECTIVE: To compare the incidence of silent cerebral infarction and impact on cognitive function following transcatheter aortic valve implantation (TAVI) with the first-generation CoreValve (Medtronic, Minneapolis, Minnesota, USA) and second-generation Lotus valve (Boston Scientific, Natick Massachusetts, USA). DESIGN: A prospective observational study comprising a 1.5 T cerebral MRI scan, performed preoperatively and immediately following TAVI, and neurocognitive assessments performed at baseline, 30 days and 1 year follow-up. SETTING: University hospitals of Leeds and Leicester, UK. PATIENTS: 66 (80.6±8.0 years, 47% male) patients with high-risk severe symptomatic aortic stenosis recruited between April 2012 and May 2015. MAIN OUTCOME MEASURES: Incidence of new cerebral microinfarction and objective decline in neurocognitive performance. RESULTS: All underwent cerebral MRI at baseline and immediately following TAVI, and 49 (25 Lotus, 24 CoreValve) completed neurocognitive assessments at baseline, 30 days and 1 year. There was a significantly greater incidence of new cerebral microinfarction observed following the Lotus TAVI (23 (79%) vs 22 (59%), p=0.025) with a greater number of new infarcts per patient (median 3.5 (IQR 7.0) vs 2.0 (IQR 3.0), p=0.002). The mean volume of infarcted cerebral tissue per patient was equivalent following the two prostheses (p=0.166). More patients suffered new anterior (14 (48%) vs 2 (5%), p=0.001) and vertebrobasilar (15 (52%) vs 7 (19%), p=0.005) lesions following Lotus. Lotus was associated with a decline in verbal memory and psychomotor speed at 30 days. However, performance longitudinally at 1 year was preserved in all neurocognitive domains. CONCLUSIONS: There was a higher incidence of silent cerebral microinfarction and a greater number of lesions per patient following Lotus compared with CoreValve. However, there was no objective decline in neurocognitive function discernible at 1 year following TAVI with either prosthesis.


Subject(s)
Aortic Valve Stenosis/surgery , Cerebral Infarction/physiopathology , Cognition , Heart Valve Prosthesis/classification , Transcatheter Aortic Valve Replacement/adverse effects , Aged , Aged, 80 and over , Cerebral Infarction/diagnostic imaging , Diffusion Magnetic Resonance Imaging , Female , Humans , Male , Mental Status and Dementia Tests , Prospective Studies , Prosthesis Design , Risk Factors , Severity of Illness Index , Time Factors , Treatment Outcome , United Kingdom
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