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2.
Endoscopy ; 51(8): 733-741, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31174223

RESUMO

BACKGROUND: The post-colonoscopy colorectal cancer (PCCRC) rate is a key quality indicator for colonoscopy. Previously published PCCRC rates have been difficult to compare owing to differences in methodology. The primary aim of this study was to compare Danish PCCRC rates internationally and to calculate Danish PCCRC rates using the World Endoscopy Organization (WEO) consensus method for future comparison. The secondary aim was to identify factors associated with PCCRC. METHODS: National registries were used to examine the risk of PCCRC. The Danish 3-year rate of PCCRC (PCCRC-3yr) was calculated using previously published methods from England, Sweden, and the WEO. Poisson regression analysis was performed to identify factors associated with PCCRC. RESULTS: The Danish PCCRC-3yr was significantly higher than the rate in the English NHS (relative risk [RR] 1.12, 95 % confidence interval [CI] 1.05 - 1.19) and Sweden (RR 1.15, 95 %CI 1.06 - 1.24). The Danish PCCRC-3yr based on the WEO consensus method fell from 22.5 % in 2001 to 7.9 % in 2012. The multivariable Poisson regression model found PCCRC to be significantly associated with diverticulitis (RR 3.25, 95 %CI 2.88 - 3.66), ulcerative colitis (RR 3.44, 95 %CI 2.79 - 4.23), hereditary cancer (age < 60 years: RR 7.39, 95 %CI 5.77 - 9.47; age ≥ 60 years: RR 3.81, 95 %CI 2.74 - 5.31), and location in the transverse (RR 1.57, 95 %CI 1.28 - 1.94) and ascending colon (RR 1.85, 95 %CI 1.64 - 2.08). CONCLUSIONS: The PCCRC-3yr was higher in Denmark than in comparable countries. Differences in colonoscopist training, background, and certification are possible contributing factors. A review of colonoscopist training and certification in Denmark, and continuous audit and feedback of colonoscopist performance may reduce PCCRC-3yr.


Assuntos
Colonoscopia , Neoplasias Colorretais/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Dinamarca/epidemiologia , Inglaterra/epidemiologia , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Sistema de Registros , Risco , Medicina Estatal , Suécia/epidemiologia
3.
Diabetes Obes Metab ; 21(4): 749-760, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30456918

RESUMO

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of liver diseases, of which the first stage is steatosis. It is one of the most common liver diseases in developed countries and there is a clear association between type 2 diabetes (T2DM) and NAFLD. It is estimated that 70% of people with T2DM have NAFLD and yet there is currently no licensed pharmacological agent to treat it. Whilst lifestyle modification may ameliorate liver fat, it is often difficult to achieve or sustain; thus, there is great interest in pharmacological treatments for NAFLD. Metformin is the first-line medication in the management of T2DM and evidence from animal and human studies has suggested that it may be useful in reducing liver fat via inhibition of lipogenesis and increased fatty acid oxidation. Findings from the majority of studies undertaken in rodent models clearly suggest that metformin may be a powerful therapeutic agent specifically to reduce liver fat accumulation; data from human studies are less convincing. In the present review we discuss the evidence for the specific effects of metformin treatment on liver fat accumulation in animal and human studies, as well as the underlying proposed mechanisms, to try and understand and reconcile the difference in findings between rodent and human work in this area.


Assuntos
Hipoglicemiantes/uso terapêutico , Metformina/uso terapêutico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Ácidos Graxos/metabolismo , Humanos , Hipoglicemiantes/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipogênese/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Metformina/farmacologia , Camundongos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Oxirredução/efeitos dos fármacos , Ratos , Triglicerídeos/metabolismo
4.
Microb Cell Fact ; 18(1): 10, 2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30657054

RESUMO

BACKGROUND: Many valuable biopharmaceutical and biotechnological proteins have been produced in Escherichia coli, however these proteins are almost exclusively localised in the cytoplasm or periplasm. This presents challenges for purification, i.e. the removal of contaminating cellular constituents. One solution is secretion directly into the surrounding media, which we achieved via the 'hijack' of the flagellar type III secretion system (FT3SS). Ordinarily flagellar subunits are exported through the centre of the growing flagellum, before assembly at the tip. However, we exploit the fact that in the absence of certain flagellar components (e.g. cap proteins), monomeric flagellar proteins are secreted into the supernatant. RESULTS: We report the creation and iterative improvement of an E. coli strain, by means of a modified FT3SS and a modular plasmid system, for secretion of exemplar proteins. We show that removal of the flagellin and HAP proteins (FliC and FlgKL) resulted in an optimal prototype. We next developed a high-throughput enzymatic secretion assay based on cutinase. This indicated that removal of the flagellar motor proteins, motAB (to reduce metabolic burden) and protein degradation machinery, clpX (to boost FT3SS levels intracellularly), result in high capacity secretion. We also show that a secretion construct comprising the 5'UTR and first 47 amino acidsof FliC from E. coli (but no 3'UTR) achieved the highest levels of secretion. Upon combination, we show a 24-fold improvement in secretion of a heterologous (cutinase) enzyme over the original strain. This improved strain could export a range of pharmaceutically relevant heterologous proteins [hGH, TrxA, ScFv (CH2)], achieving secreted yields of up to 0.29 mg L-1, in low cell density culture. CONCLUSIONS: We have engineered an E. coli which secretes a range of recombinant proteins, through the FT3SS, to the extracellular media. With further developments, including cell culture process strategies, we envision further improvement to the secreted titre of recombinant protein, with the potential application for protein production for biotechnological purposes.


Assuntos
Escherichia coli/metabolismo , Engenharia Metabólica , Sistemas de Secreção Tipo III/metabolismo , Regiões 5' não Traduzidas , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Escherichia coli/crescimento & desenvolvimento , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Flagelos/metabolismo , Flagelina/genética , Hormônio do Crescimento Humano/genética , Hormônio do Crescimento Humano/metabolismo , Humanos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Tiorredoxinas/genética , Tiorredoxinas/metabolismo
5.
Cell Tissue Bank ; 18(4): 597-604, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28717878

RESUMO

Two-step perfusion is considered the gold standard method for isolating hepatocytes from human liver tissue. As perfusion may require a large tissue specimen, which is encapsulated and has accessible vessels for cannulation, only a limited number of tissue samples may be suitable. Therefore, the aim of this work was to develop an alternative method to isolate hepatocytes from non-encapsulated and small samples of human liver tissue. Healthy tissue from 44 human liver resections were graded for steatosis and tissue weights between 7.8 and 600 g were used for hepatocyte isolations. Tissue was diced and underwent a two-step digestion (EDTA and collagenase). Red cell lysis buffer was used to prevent red blood cell contamination and toxicity. Isolated hepatocyte viability was determined by trypan blue exclusion. Western blot and biochemical analyses were undertaken to ascertain cellular phenotype and function. Liver tissue that weighed ≥50 g yielded significantly higher (P < 0.01) cell viability than tissue <50 g. Viable cells secreted urea and displayed the phenotypic hepatocyte markers albumin and cytochrome P450. Presence of steatosis in liver tissue or intra-hepatocellular triglyceride content had no effect on cell viability. This methodology allows for the isolation of viable primary human hepatocytes from small amounts of "healthy" resected liver tissue which are not suitable for perfusion. This work provides the opportunity to increase the utilisation of resection surplus tissue, and may ultimately lead to an increased number of in vitro cellular studies being undertaken using the gold-standard model of human primary hepatocytes.


Assuntos
Separação Celular , Sobrevivência Celular/fisiologia , Hepatócitos/citologia , Fígado/citologia , Adulto , Idoso , Albuminas/metabolismo , Separação Celular/métodos , Células Cultivadas , Colagenases/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
6.
Am J Physiol Endocrinol Metab ; 308(1): E1-20, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25352434

RESUMO

The liver is a main metabolic organ in the human body and carries out a vital role in lipid metabolism. Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, encompassing a spectrum of conditions from simple fatty liver (hepatic steatosis) through to cirrhosis. Although obesity is a known risk factor for hepatic steatosis, it remains unclear what factor(s) is/are responsible for the primary event leading to retention of intrahepatocellular fat. Studying hepatic processes and the etiology and progression of disease in vivo in humans is challenging, not least as NAFLD may take years to develop. We present here a review of experimental models and approaches that have been used to assess liver triglyceride metabolism and discuss their usefulness in helping to understand the aetiology and development of NAFLD.


Assuntos
Fígado/metabolismo , Modelos Animais , Modelos Biológicos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Triglicerídeos/metabolismo , Animais , Células Cultivadas , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Metabolismo dos Lipídeos/fisiologia , Masculino
7.
Am J Physiol Endocrinol Metab ; 309(6): E511-22, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26126685

RESUMO

The development of hepatocyte cell models that represent fatty acid partitioning within the human liver would be beneficial for the study of the development and progression of nonalcoholic fatty liver disease (NAFLD). We sought to develop and characterize a novel human liver cell line (LIV0APOLY) to establish a model of lipid accumulation using a physiological mixture of fatty acids under low- and high-glucose conditions. LIV0APOLY cells were compared with a well-established cell line (HepG2) and, where possible, primary human hepatocytes. LIV0APOLY cells were found to proliferate and express some mature liver markers and were wild type for the PNPLA3 (rs738409) gene, whereas HepG2 cells carried the Ile(148)Met variant that is positively associated with liver fat content. Intracellular triglyceride content was higher in HepG2 than in LIV0APOLY cells; exposure to high glucose and/or exogenous fatty acids increased intracellular triglyceride in both cell lines. Triglyceride concentrations in media were higher from LIV0APOLY compared with HepG2 cells. Culturing LIV0APOLY cells in high glucose increased a marker of endoplasmic reticulum stress and attenuated insulin-stimulated Akt phosphorylation whereas low glucose and exogenous fatty acids increased AMPK phosphorylation. Although LIV0APOLY cells and primary hepatocytes stored similar amounts of exogenous fatty acids as triglyceride, more exogenous fatty acids were partitioned toward oxidation in the LIV0APOLY cells than in primary hepatocytes. LIV0APOLY cells offer the potential to be a renewable cellular model for studying the effects of exogenous metabolic substrates on fatty acid partitioning; however, their usefulness as a model of lipoprotein metabolism needs to be further explored.


Assuntos
Ácidos Graxos/metabolismo , Glucose/metabolismo , Hepatócitos/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Triglicerídeos/metabolismo , Linhagem Celular , Estresse do Retículo Endoplasmático , Células Hep G2 , Humanos , Insulina/metabolismo , Lipase/genética , Proteínas de Membrana/genética , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo
8.
Pharmacol Res ; 100: 24-35, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26196248

RESUMO

Mitophagy is a cellular mechanism for the recycling of mitochondrial fragments. This process is able to improve mitochondrial DNA (mtDNA) quality in heteroplasmic mtDNA disease, in which mutant mtDNA co-exists with normal mtDNA. In disorders where the load of mutant mtDNA determines disease severity it is likely to be an important determinant of disease progression. Measuring mitophagy is technically demanding. We used pharmacological modulators of autophagy to validate two techniques for quantifying mitophagy. First we used the IN Cell 1000 analyzer to quantify mitochondrial co-localisation with LC3-II positive autophagosomes. Unlike conventional fluorescence and electron microscopy, this high-throughput system is sufficiently sensitive to detect transient low frequency autophagosomes. Secondly, because mitophagy preferentially removes pathogenic heteroplasmic mtDNA mutants, we developed a heteroplasmy assay based on loss of m.3243A>G mtDNA, during culture conditions requiring oxidative metabolism ("energetic stress"). The effects of the pharmacological modulators on these two measures were consistent, confirming that the high throughput imaging output (autophagosomes co-localising with mitochondria) reflects mitochondrial quality control. To further validate these methods, we performed a more detailed study using metformin, the most commonly prescribed antidiabetic drug that is still sometimes used in Maternally Inherited Diabetes and Deafness (MIDD). This confirmed our initial findings and revealed that metformin inhibits mitophagy at clinically relevant concentrations, suggesting that it may have novel therapeutic uses.


Assuntos
Autofagia/fisiologia , Bioensaio/métodos , DNA Mitocondrial/genética , Mitocôndrias/genética , Mitocôndrias/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Autofagia/efeitos dos fármacos , DNA Mitocondrial/efeitos dos fármacos , Humanos , Metformina/farmacologia , Microscopia de Fluorescência/métodos , Pessoa de Meia-Idade , Mitocôndrias/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Mitofagia/fisiologia , Adulto Jovem
9.
Liver Int ; 34(7): e180-90, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24621397

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is not a single disease entity, rather it describes a spectrum of liver conditions that range from fatty liver (steatosis) to more severe steatosis coupled with marked inflammation and fibrosis [non-alcoholic steatohepatitis (NASH)] to severe liver disease such as cirrhosis and possibly hepatocellular carcinoma. Obesity, notably abdominal obesity, is a common risk factor for NAFLD. The pathogenesis from steatosis to NASH is poorly understood, and the 'two hit' model, as suggested nearly two decades ago, provides a feasible starting point for characterization of underlying mechanisms. This review will examine the oxidative stress factors ('triggers') which have been implicated as a 'second hit' in the development of primary NASH. It would be reasonable to assume that multiple, rather than single, pro-oxidative intracellular and extracellular triggers act in conjunction promoting oxidative stress that drives the development of NASH. It is likely that the common denominator of these pro-oxidative triggers is mitochondrial dysfunction. Understanding the contribution of each of these 'triggers' is an essential step in starting to understand and elucidate the mechanisms responsible for progression from steatosis to NASH, thus enabling the development of therapeutic targeting to prevent NASH development and progression.


Assuntos
Estresse do Retículo Endoplasmático/fisiologia , Fígado Gorduroso/complicações , Fígado Gorduroso/epidemiologia , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Hepatopatia Gordurosa não Alcoólica/etiologia , Obesidade Abdominal/epidemiologia , Estresse Oxidativo/fisiologia , Progressão da Doença , Humanos , Mitocôndrias/patologia , Modelos Biológicos , Fatores de Risco
10.
Science ; 383(6687): 1122-1130, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38452070

RESUMO

Eukaryotic genomes are organized by loop extrusion and sister chromatid cohesion, both mediated by the multimeric cohesin protein complex. Understanding how cohesin holds sister DNAs together, and how loss of cohesion causes age-related infertility in females, requires knowledge as to cohesin's stoichiometry in vivo. Using quantitative super-resolution imaging, we identified two discrete populations of chromatin-bound cohesin in postreplicative human cells. Whereas most complexes appear dimeric, cohesin that localized to sites of sister chromatid cohesion and associated with sororin was exclusively monomeric. The monomeric stoichiometry of sororin:cohesin complexes demonstrates that sister chromatid cohesion is conferred by individual cohesin rings, a key prediction of the proposal that cohesion arises from the co-entrapment of sister DNAs.


Assuntos
Proteínas de Ciclo Celular , Cromátides , Coesinas , Troca de Cromátide Irmã , Humanos , Proteínas de Ciclo Celular/metabolismo , Cromátides/metabolismo , Cromatina/metabolismo , Coesinas/metabolismo , DNA/genética , DNA/metabolismo , Linhagem Celular Tumoral
11.
J Biol Chem ; 287(24): 20088-99, 2012 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-22511782

RESUMO

The importance of AMP-activated protein kinase (AMPK) and protein kinase C (PKC) as effectors of metformin (Met) action on glucose uptake (GU) in skeletal muscle cells was investigated. GU in L6 myotubes was stimulated 2-fold following 16 h of Met treatment and acutely enhanced by insulin in an additive fashion. Insulin-stimulated GU was sensitive to PI3K inhibition, whereas that induced by Met was not. Met and its related biguanide, phenformin, stimulated AMPK activation/phosphorylation to a level comparable with that induced by the AMPK activator, 5-amino-1-ß-d-ribofuranosyl-imidazole-4-carboxamide (AICAR). However, the increase in GU elicited by AICAR was significantly lower than that induced by either biguanide. Expression of a constitutively active AMPK mimicked the effects of AICAR on GU, whereas a dominant interfering AMPK or shRNA silencing of AMPK prevented AICAR-stimulated GU and Met-induced AMPK signaling but only repressed biguanide-stimulated GU by ∼20%. Consistent with this, analysis of GU in muscle cells from α1(-/-)/α2(-/-) AMPK-deficient mice revealed a significant retention of Met-stimulated GU, being reduced by ∼35% compared with that of wild type cells. Atypical PKCs (aPKCs) have been implicated in Met-stimulated GU, and in line with this, Met and phenformin induced activation/phosphorylation of aPKC in L6 myotubes. However, although cellular depletion of aPKC (>90%) led to loss in biguanide-induced aPKC phosphorylation, it had no effect on Met-stimulated GU, whereas inhibitors targeting novel/conventional PKCs caused a significant reduction in biguanide-induced GU. Our findings indicate that although Met activates AMPK, a significant component of Met-stimulated GU in muscle cells is mediated via an AMPK-independent mechanism that involves novel/conventional PKCs.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Glucose/metabolismo , Hipoglicemiantes/farmacologia , Metformina/farmacologia , Fibras Musculares Esqueléticas/enzimologia , Proteína Quinase C/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/genética , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Ativadores de Enzimas/farmacologia , Glucose/genética , Camundongos , Camundongos Knockout , Fibras Musculares Esqueléticas/citologia , Fenformin/farmacologia , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Proteína Quinase C/genética , Ribonucleotídeos/farmacologia , Fatores de Tempo
12.
Biol Reprod ; 89(3): 51, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23759309

RESUMO

Maternal diet can significantly skew the secondary sex ratio away from the expected value of 0.5 (proportion males), but the details of how diet may do this are unclear. Here, we altered dietary levels of salt (4% salt in the feed) and/or fructose (10% in the drinking water) of pregnant rats to model potential effects that consumption of a "Western diet" might have on maternofetal growth, development, and sex ratio. We demonstrate that excess fructose consumption before and during pregnancy lead to a marked skew in the secondary sex ratio (proportion of males, 0.60; P < 0.006). The effect was not mediated by selective developmental arrest of female embryos or influenced by fetal position in the uterine horn or sex-specific effects on sperm motility, suggesting a direct effect of glycolyzable monosaccharide on the maternal ovary and/or ovulated oocyte. Furthermore, combined excess maternal consumption of salt and fructose-sweetened beverage significantly reduced fertility, reflected as a 50% reduction in preimplantation and term litter size. In addition, we also noted birth order effects in the rat, with sequential implantation sites tending to be occupied by the same sex.


Assuntos
Ordem de Nascimento , Fertilidade/efeitos dos fármacos , Frutose/administração & dosagem , Crescimento e Desenvolvimento/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Pré-Natal , Reprodução/efeitos dos fármacos , Razão de Masculinidade , Cloreto de Sódio na Dieta/administração & dosagem , Animais , Ingestão de Alimentos/fisiologia , Feminino , Masculino , Gravidez , Resultado da Gravidez , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Ratos , Ratos Sprague-Dawley
13.
Sci Data ; 10(1): 655, 2023 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-37749083

RESUMO

Advancing age is the greatest risk factor for developing multiple age-related diseases. Therapeutic approaches targeting the underlying pathways of ageing, rather than individual diseases, may be an effective way to treat and prevent age-related morbidity while reducing the burden of polypharmacy. We harness the Open Targets Genetics Portal to perform a systematic analysis of nearly 1,400 genome-wide association studies (GWAS) mapped to 34 age-related diseases and traits, identifying genetic signals that are shared between two or more of these traits. Using locus-to-gene (L2G) mapping, we identify 995 targets with shared genetic links to age-related diseases and traits, which are enriched in mechanisms of ageing and include known ageing and longevity-related genes. Of these 995 genes, 128 are the target of an approved or investigational drug, 526 have experimental evidence of binding pockets or are predicted to be tractable, and 341 have no existing tractability evidence, representing underexplored genes which may reveal novel biological insights and therapeutic opportunities. We present these candidate targets for exploration and prioritisation in a web application.


Assuntos
Envelhecimento , Estudo de Associação Genômica Ampla , Multimorbidade , Longevidade , Fenótipo , Envelhecimento/genética , Humanos
14.
Inorg Chem ; 51(1): 463-71, 2012 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-22145812

RESUMO

Synthetic methods toward ruthenium(II) complexes incorporating the benzo[i]dipyrido[3,2-a:2',3'-c]phenazine-11,16-quinone ligand, qdppn, are reported. In several cases, it was found that complexes containing coordinated benzo[i]dipyrido[3,2-a:2',3'-c]phenazine, dppn, could be chemically or photochemically oxidized to their qdppn analogues. Since this method was not possible in all the cases, a new, higher yielding, convenient synthesis of qdppn was developed. The crystal structure of the complex [Ru(phen)(2)(qppn)](PF(6))(2) (phen = 1,10-phenanthroline) which was synthesized from free qdppn reveals that a combination of π-π stacking between coordinated phen and qdppn units, as well as anion-ligand hydrogen bonding, define large hexagonal channels which are occupied by anions and solvent molecules. Electrochemical and photophysical studies reveal that the new qdppn-based complexes are not luminescent and, in contrast to their dppn analogues, they are also poor singlet oxygen sensitizers. Time-resolved studies and density functional theory (DFT) calculations indicate that optical properties of the new complexes are due to a short-lived charge separated state involving the quinone moiety of qdppn. The DNA binding properties of the new complexes have also been investigated. It was found that they are intercalators, displaying binding affinities which are comparable to their dppn analogues.


Assuntos
Complexos de Coordenação/química , DNA/metabolismo , Substâncias Intercalantes/química , Fenazinas/química , Rutênio/química , Animais , Bovinos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Substâncias Intercalantes/síntese química , Substâncias Intercalantes/farmacologia , Ligantes , Modelos Moleculares , Oxirredução , Fenantrolinas/síntese química , Fenantrolinas/química , Fenantrolinas/farmacologia , Fenazinas/síntese química , Fenazinas/farmacologia , Quinonas/síntese química , Quinonas/química , Quinonas/farmacologia , Rutênio/farmacologia
15.
Biochem J ; 435(2): 463-74, 2011 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-21323644

RESUMO

Sustained over-supply of saturated non-esterified 'free' fatty acids has been shown to promote skeletal muscle insulin resistance, which may be driven, in part, by an increase in inflammatory signalling within this tissue. In the present manuscript we show that exposure of L6 myotubes to palmitate, a saturated fatty acid, induces activation of the NF-κB (nuclear factor κB) pathway {based on increased IKK [IκB (inhibitory κB) kinase] phosphorylation, IκBα loss and elevated interleukin-6 mRNA expression} and that this was associated with enhanced phosphorylation/activation of p38 MAPK (mitogen-activated protein kinase), JNK (c-Jun N-terminal kinase) and ERK (extracellular-signal-regulated kinase) as well as impaired insulin-dependent activation of PKB (protein kinase B)/Akt and glucose transport. NF-κB activation by palmitate was unaffected by pharmacological inhibition of p38 MAPK or JNK, but was suppressed significantly by inhibition of MEK (MAPK/ERK kinase)/ERK signalling. The importance of ERK with respect to downstream NF-κB signalling was underscored by the finding that PMA, a potent ERK activator, enhanced IKK phosphorylation. Strikingly, both palmitate- and PMA-induced activation of IKK/NF-κB were antagonized by AMPK (AMP-activated protein kinase) activators because of reduced ERK signalling. Although palmitate-induced activation of NF-κB was repressed by AMPK activation and by cellular overexpression of a mutated IκBα (S32A/S36A) super-repressor, this did not ameliorate the loss in insulin-stimulated PKB activation or glucose transport. Our results from the present study indicate that ERK plays a pivotal role in palmitate-induced activation of the IKK/NF-κB signalling axis and that AMPK can restrain the activity of this pro-inflammatory pathway. The finding that insulin resistance persists in myotubes in which NF-κB signalling has been repressed implies that palmitate and/or its lipid derivatives retain the capacity to impair insulin-regulated events independently of the increase in inflammatory signalling.


Assuntos
Proteínas Quinases Ativadas por AMP/fisiologia , Ácidos Graxos/farmacologia , Músculo Esquelético/efeitos dos fármacos , NF-kappa B/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Células Cultivadas , Humanos , Inflamação/induzido quimicamente , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Resistência à Insulina/fisiologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/fisiologia , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Ácido Palmítico/farmacologia , Ratos , Transdução de Sinais/efeitos dos fármacos
16.
Eur J Endocrinol ; 186(3): 367-377, 2022 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-35038311

RESUMO

OBJECTIVE: Metformin is a first-line pharmacotherapy in the treatment of type 2 diabetes, a condition closely associated with non-alcoholic fatty liver disease (NAFLD). Although metformin promotes weight loss and improves insulin sensitivity, its effect on intrahepatic triglyceride (IHTG) remains unclear. We investigated the effect of metformin on IHTG, hepatic de novo lipogenesis (DNL), and fatty acid (FA) oxidation in vivo in humans. DESIGN AND METHODS: Metabolic investigations, using stable-isotope tracers, were performed in ten insulin-resistant, overweight/obese human participants with NAFLD who were treatment naïve before and after 12 weeks of metformin treatment. The effect of metformin on markers of s.c. adipose tissue FA metabolism and function, along with the plasma metabolome, was investigated. RESULTS: Twelve weeks of treatment with metformin resulted in a significant reduction in body weight and improved insulin sensitivity, but IHTG content and FA oxidation remained unchanged. Metformin treatment was associated with a significant decrease in VLDL-triglyceride (TG) concentrations and a significant increase in the relative contribution of DNL-derived FAs to VLDL-TG. There were subtle and relatively few changes in s.c. adipose tissue FA metabolism and the plasma metabolome with metformin treatment. CONCLUSIONS: We demonstrate the mechanisms of action of metformin whereby it improves insulin sensitivity and promotes weight loss, without improvement in IHTG; these observations are partly explained through increased hepatic DNL and a lack of change in FA oxidation.


Assuntos
Hipoglicemiantes/uso terapêutico , Resistência à Insulina/fisiologia , Lipogênese/fisiologia , Fígado/metabolismo , Metformina/uso terapêutico , Triglicerídeos/metabolismo , Adulto , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Estudos de Coortes , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Humanos , Hipoglicemiantes/farmacologia , Lipogênese/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Metformina/farmacologia , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Sobrepeso/tratamento farmacológico , Sobrepeso/metabolismo
17.
Exerc Immunol Rev ; 17: 6-63, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21446352

RESUMO

An ever-growing volume of peer-reviewed publications speaks to the recent and rapid growth in both scope and understanding of exercise immunology. Indeed, more than 95% of all peer-reviewed publications in exercise immunology (currently >2, 200 publications using search terms "exercise" and "immune") have been published since the formation of the International Society of Exercise and Immunology (ISEI) in 1989 (ISI Web of Knowledge). We recognise the epidemiological distinction between the generic term "physical activity" and the specific category of "exercise", which implies activity for a specific purpose such as improvement of physical condition or competition. Extreme physical activity of any type may have implications for the immune system. However, because of its emotive component, exercise is likely to have a larger effect, and to date the great majority of our knowledge on this subject comes from exercise studies.


Assuntos
Exercício Físico , Sistema Imunitário/fisiologia , Humanos , Imunidade Inata , Imunidade nas Mucosas , Inflamação/prevenção & controle , Linfócitos/imunologia , Neoplasias/prevenção & controle , Neutrófilos/imunologia , Infecções Respiratórias/etiologia , Infecções Respiratórias/imunologia
18.
SLAS Discov ; 26(6): 749-756, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33724070

RESUMO

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) represents a significant threat to human health. Despite its similarity to related coronaviruses, there are currently no specific treatments for COVID-19 infection, and therefore there is an urgent need to develop therapies for this and future coronavirus outbreaks. Formation of the cap at the 5' end of viral RNA has been shown to help coronaviruses evade host defenses. Nonstructural protein 14 (nsp14) is responsible for N7-methylation of the cap guanosine in coronaviruses. This enzyme is highly conserved among coronaviruses and is a bifunctional protein with both N7-methyltransferase and 3'-5' exonuclease activities that distinguish nsp14 from its human equivalent. Mutational analysis of SARS-CoV nsp14 highlighted its role in viral replication and translation efficiency of the viral genome. In this paper, we describe the characterization and development of a high-throughput assay for nsp14 utilizing RapidFire technology. The assay has been used to screen a library of 1771 Food and Drug Administration (FDA)-approved drugs. From this, we have validated nitazoxanide as a selective inhibitor of the methyltransferase activity of nsp14. Although modestly active, this compound could serve as a starting point for further optimization.


Assuntos
Antivirais/farmacologia , Exorribonucleases/antagonistas & inibidores , Ensaios de Triagem em Larga Escala , Nitrocompostos/farmacologia , Capuzes de RNA/antagonistas & inibidores , RNA Viral/antagonistas & inibidores , SARS-CoV-2/efeitos dos fármacos , Tiazóis/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Antiparasitários/química , Antiparasitários/farmacologia , Antivirais/química , COVID-19/virologia , Clonagem Molecular , Reposicionamento de Medicamentos , Ensaios Enzimáticos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Escherichia coli/genética , Escherichia coli/metabolismo , Exorribonucleases/genética , Exorribonucleases/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Cinética , Espectrometria de Massas/métodos , Metilação , Nitrocompostos/química , Medicamentos sob Prescrição/química , Medicamentos sob Prescrição/farmacologia , Capuzes de RNA/genética , Capuzes de RNA/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , SARS-CoV-2/enzimologia , SARS-CoV-2/genética , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Tiazóis/química , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacos
19.
Am J Physiol Cell Physiol ; 299(2): C240-50, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20410436

RESUMO

Sodium pyruvate can increase mitochondrial biogenesis in C2C12 myoblasts in a peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC1alpha)-independent manner. The present study examined the effect of 72-h treatment with sodium pyruvate (5-50 mM) or sodium chloride (50 mM) as an osmotic control on the regulation of mitochondrial substrate metabolism and biogenesis in C2C12 myotubes. Pyruvate (50 mM) increased the levels of fatty acid oxidation enzymes (CD36, 61%, and beta-oxidative enzyme 3-hydroxyacyl-CoA dehydrogenase, 54%) and the expression of cytochrome-c oxidase subunit I (220%) and cytochrome c (228%), consistent with its previous described role as a promoter of mitochondrial biogenesis. However, in contrast, pyruvate treatment reduced glucose transporter 4 (42%), phosphofructokinase (57%), and PGC1alpha (72%) protein content as well as PGC1alpha (48%) and PGC1beta (122%) mRNA. The decrease in PGC1alpha was compensated for by an increase in the PGC1alpha-related coactivator (PRC; 187%). Pyruvate treatment reduced basal and insulin-stimulated glucose uptake (41% and 31%, respectively) and palmitate uptake and oxidation (24% and 31%, respectively). The addition of the pyruvate dehydrogenase activator dichloroacetate (DCA) and the TCA precursor glutamine increased PGC1alpha expression (368%) and returned PRC expression to basal. Glucose uptake increased by 4.2-fold with DCA and glutamine and palmitate uptake increased by 18%. Coupled to this adaptation was an 80% increase in oxygen consumption. The data suggest that supraphysiological doses of pyruvate decrease mitochondrial function despite limited biogenesis and that anaplerotic agents can reverse this effect.


Assuntos
Regulação para Baixo/fisiologia , Transporte de Elétrons/fisiologia , Fibras Musculares Esqueléticas/metabolismo , Ácido Pirúvico/farmacologia , Transativadores/antagonistas & inibidores , Regulação para Cima/fisiologia , Animais , Linhagem Celular , Células Cultivadas , Ciclo do Ácido Cítrico/efeitos dos fármacos , Ciclo do Ácido Cítrico/fisiologia , Regulação para Baixo/efeitos dos fármacos , Transporte de Elétrons/efeitos dos fármacos , Camundongos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Especificidade por Substrato/efeitos dos fármacos , Especificidade por Substrato/fisiologia , Transativadores/biossíntese , Fatores de Transcrição , Regulação para Cima/efeitos dos fármacos
20.
Drug Discov Today ; 25(8): 1403-1415, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32574698

RESUMO

Advanced age is the major risk factor for multimorbidity. Current clinical practice treats the individual age-related diseases, resulting in polypharmacy. Thus, targeting the biological processes that drive ageing could prevent both multimorbidity and polypharmacy.


Assuntos
Envelhecimento , Descoberta de Drogas , Multimorbidade , Envelhecimento/genética , Animais , Biomarcadores , Hotspot de Doença , Humanos
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