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1.
Clin Infect Dis ; 76(8): 1449-1458, 2023 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-36520995

RESUMO

BACKGROUND: Head and neck squamous cell cancer (HNSCC) occurs at higher rates among persons with HIV (PWH). This study compares the impact of sociodemographic and clinicopathologic characteristics on outcomes among PWH-HNSCC compared with HNSCC patients without HIV. METHODS: Patient data from HNSCC individuals were collected at a single academic hospital center between 2002 and 2018. Forty-eight patients with HIV (HIV-HNSCC) and 2894 HNSCC patients without HIV were included. Multivariate analysis determined predictors of survival using Cox proportional hazards regression model. HIV-positive and -negative tumors were analyzed by quantitative immunofluorescence for expression of CD4, CD8, CD20 and PD-L1. RESULTS: HIV-HNSCC patients had a lower median overall survival than HNSCC patients without HIV (34 [18-84] vs 94 [86-103] months; P < .001). In multivariate analysis that included age, sex, race/ethnicity, stage, site, tobacco use, time to treatment initiation, and insurance status, HIV was an independent predictor of poorer survival, with a hazard ratio of 1.98 (95% CI: 1.32-2.97; P < .001). PWH with human papillomavirus (HPV)-positive oropharyngeal tumors also had worse prognosis than HPV-positive oropharyngeal tumors in the population without HIV (P < .001). The tumor microenvironment among HIV-HNSCC patients revealed lower intratumoral CD8 infiltration among HIV+ HPV+ tumors compared with HIV- HPV+ tumors (P = .04). CONCLUSIONS: HIV-HNSCC patients had worse prognosis than the non-HIV population, with HIV being an independent predictor of poor clinical outcomes when accounting for important sociodemographic and clinicopathologic factors. Our findings highlight differences in tumor biology that require further detailed characterization in large cohorts and increased inclusion of PWH in immunotherapy trials.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Orofaríngeas , Infecções por Papillomavirus , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/complicações , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/terapia , HIV , Infecções por Papillomavirus/epidemiologia , Neoplasias de Cabeça e Pescoço/complicações , Prognóstico , Microambiente Tumoral
2.
BMC Med Educ ; 20(1): 442, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33203404

RESUMO

BACKGROUND: Vaccination is the most cost-effective medical intervention known to prevent morbidity and mortality. However, data are limited on the effectiveness of residency programs in delivering immunization knowledge and skills to trainees. The authors sought to describe the immunization competency needs of medical residents at the University of Toronto (UT), and to develop and evaluate a pilot immunization curriculum. METHODS: Residents at the University of Toronto across nine specialties were recruited to attend a pilot immunization workshop in November 2018. Participants completed a questionnaire before and after the workshop to assess immunization knowledge and compare baseline change. Feedback was also surveyed on the workshop content and process. Descriptive statistics were performed on the knowledge questionnaire and feedback survey. A paired sample T-test compared questionnaire answers before and after the workshop. Descriptive coding was used to identify themes from the feedback survey. RESULTS: Twenty residents from at least six residencies completed the pre-workshop knowledge questionnaire, seventeen attended the workshop, and thirteen completed the post-workshop questionnaire. Ninety-five percent (19/20) strongly agreed that vaccine knowledge was important to their career, and they preferred case-based teaching. The proportion of the thirty-four knowledge questions answered correctly increased from 49% before the workshop to 67% afterwards, with a mean of 2.24 (CI: 1.43, 3.04) more correct answers (P < 0.001). Sixteen residents completed the post-workshop feedback survey. Three themes emerged: first, they found the content specific and practical; second, they wanted more case-based learning and for the workshop to be longer; and third, they felt the content and presenters were of high quality. CONCLUSIONS: Findings from this study suggest current immunization training of UT residents does not meet their training competency requirements. The study's workshop improved participants' immunization knowledge. The information from this study could be used to develop residency immunization curriculum at UT and beyond.


Assuntos
Internato e Residência , Currículo , Educação de Pós-Graduação em Medicina , Retroalimentação , Humanos , Imunização , Vacinação
3.
J Lipid Res ; 58(8): 1561-1578, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28583918

RESUMO

GPR40 and GPR120 are fatty acid sensors that play important roles in glucose and energy homeostasis. GPR40 potentiates glucose-dependent insulin secretion and demonstrated in clinical studies robust glucose lowering in type 2 diabetes. GPR120 improves insulin sensitivity in rodents, albeit its mechanism of action is not fully understood. Here, we postulated that the antidiabetic efficacy of GPR40 could be enhanced by coactivating GPR120. A combination of GPR40 and GPR120 agonists in db/db mice, as well as a single molecule with dual agonist activities, achieved superior glycemic control compared with either monotherapy. Compared with a GPR40 selective agonist, the dual agonist improved insulin sensitivity in ob/ob mice measured by hyperinsulinemic-euglycemic clamp, preserved islet morphology, and increased expression of several key lipolytic genes in adipose tissue of Zucker diabetic fatty rats. Novel insights into the mechanism of action for GPR120 were obtained. Selective GPR120 activation suppressed lipolysis in primary white adipocytes, although this effect was attenuated in adipocytes from obese rats and obese rhesus, and sensitized the antilipolytic effect of insulin in rat and rhesus primary adipocytes. In conclusion, GPR120 agonism enhances insulin action in adipose tissue and yields a synergistic efficacy when combined with GPR40 agonism.


Assuntos
Tecido Adiposo/metabolismo , Diabetes Mellitus Experimental/metabolismo , Lipólise , Receptores Acoplados a Proteínas G/metabolismo , Tecido Adiposo/efeitos dos fármacos , Animais , Células CHO , Cricetinae , Cricetulus , Diabetes Mellitus Experimental/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Resistência à Insulina , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/fisiopatologia , Lipólise/efeitos dos fármacos , Masculino , Camundongos , Ratos , Receptores Acoplados a Proteínas G/agonistas
4.
Bioorg Med Chem Lett ; 26(6): 1529-1535, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26898814

RESUMO

MK-4256, a tetrahydro-ß-carboline sstr3 antagonist, was discontinued due to a cardiovascular (CV) adverse effect observed in dogs. Additional investigations revealed that the CV liability (QTc prolongation) was caused by the hERG off-target activity of MK-4256 and was not due to sstr3 antagonism. In this Letter, we describe our extensive SAR effort at the C3 position of the tetrahydro-ß-carboline structure. This effort resulted in identification of 5-fluoro-pyridin-2-yl as the optimal substituent on the imidazole ring to balance sstr3 activity and the hERG off-target liability.


Assuntos
Carbolinas/química , Carbolinas/farmacologia , Receptores de Somatostatina/antagonistas & inibidores , Animais , Carbolinas/síntese química , Cães , Relação Dose-Resposta a Droga , Humanos , Camundongos , Estrutura Molecular , Ratos , Relação Estrutura-Atividade
5.
Proc Natl Acad Sci U S A ; 108(13): 5378-83, 2011 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-21389266

RESUMO

Platensimycin (PTM) is a recently discovered broad-spectrum antibiotic produced by Streptomyces platensis. It acts by selectively inhibiting the elongation-condensing enzyme FabF of the fatty acid biosynthesis pathway in bacteria. We report here that PTM is also a potent and highly selective inhibitor of mammalian fatty acid synthase. In contrast to two agents, C75 and cerulenin, that are widely used as inhibitors of mammalian fatty acid synthase, platensimycin specifically inhibits fatty acid synthesis but not sterol synthesis in rat primary hepatocytes. PTM preferentially concentrates in liver when administered orally to mice and potently inhibits hepatic de novo lipogenesis, reduces fatty acid oxidation, and increases glucose oxidation. Chronic administration of platensimycin led to a net reduction in liver triglyceride levels and improved insulin sensitivity in db/+ mice fed a high-fructose diet. PTM also reduced ambient glucose levels in db/db mice. These results provide pharmacological proof of concept of inhibiting fatty acid synthase for the treatment of diabetes and related metabolic disorders in animal models.


Assuntos
Adamantano/uso terapêutico , Aminobenzoatos/uso terapêutico , Anilidas/uso terapêutico , Diabetes Mellitus/tratamento farmacológico , Ácido Graxo Sintases/antagonistas & inibidores , Fígado Gorduroso/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Animais , Anti-Infecciosos/uso terapêutico , Modelos Animais de Doenças , Ácidos Graxos/biossíntese , Glucose/metabolismo , Humanos , Fígado/metabolismo , Camundongos , Camundongos Mutantes , Oxirredução , Esteróis/biossíntese
6.
Food Chem Toxicol ; 185: 114499, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38309685

RESUMO

Food products simultaneously containing both food contaminants and emulsifiers are common in baked products, coffee and chocolate. Little is known regarding how food contaminants and emulsifiers interact and alter toxicity. Recent studies have shown that while emulsifiers themselves have little toxicity, they could cause changes in the gut microenvironment and lead to issues such as increased uptake of allergens. This study examined toxic effect of two common process contaminants acrylamide (AA) and benzo [a]pyrene (BAP) combined with food emulsifiers polyoxyethylene sorbitan monooleate (TW) or glycerol monostearate (G). In liver cell line HepG2 and gastrointestinal cell lines HIEC6 and Caco-2, toxicities of AA and BAP were increased by TW but not by G as indicated by decrease in IC50 values. Addition of TW also exacerbated gene expression changes caused by AA or BAP. Cellular uptake and cell membrane permeability were enhanced by TW but not by G, but tight junction proteins of Caco-2 monolayer was impacted by both emulsifiers. These results suggested that TW could increase toxicity of AA and BAP through increasing cell permeability thus chemical uptake and potentially through other interactions. The study is to draw the attention of regulators on the potential synergistic interaction of co-occurring chemicals in food.


Assuntos
Chocolate , Alimentos , Humanos , Células CACO-2 , Café , Transporte Biológico , Acrilamida/toxicidade , Benzo(a)pireno
7.
Sci Total Environ ; 944: 173985, 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-38876354

RESUMO

Contaminants such as heavy metals and polycyclic aromatic hydrocarbons (PAHs) can be released from asphalt pavement and transported through stormwater runoff to nearby water bodies, leading to water pollution and potential harm to living aquatic animals. This study characterizes the heavy metal and PAH leaching from various asphalt paving materials and their potential ecotoxicological effects on zebrafish Danio rerio. Artificial runoffs were prepared in the laboratory concerning the effects of water, temperature, and traffic. The concentrations of heavy metals and PAHs in the leachates were quantified, while the toxicity assessment encompassed mortality, metal stress, PAH toxicity, inflammation, carcinogenicity, and oxidative damage. Gene expressions of related proteins or transcription factors were assessed, including metallothionines, aryl hydrocarbon receptors, interleukin-1ß, interleukin-10, nuclear factor-κB, tumor necrosis factor-α, tumor suppressor p53, heat shock protein 70, and reactive oxygen species (ROS). The findings demonstrate that leachates from asphalt pavements containing waste bottom ash, crumb rubber, or specific chemicals could induce notable stress and inflammation responses in zebrafish. In addition, potential carcinogenic effects and the elevation of ROS were identified within certain treatment groups. This study represents the first attempt to assess the ecotoxicity of pavement leachates employing a live fish model, thereby improving the current understanding of the environmental impact of asphalt pavements.


Assuntos
Hidrocarbonetos , Metais Pesados , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Peixe-Zebra , Animais , Poluentes Químicos da Água/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos/toxicidade , Metais Pesados/toxicidade , Ecotoxicologia , Materiais de Construção , Monitoramento Ambiental
8.
J Appl Meas ; 14(4): 339-55, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24064576

RESUMO

This paper examines the residual-based fit statistics commonly used in Rasch measurement. In particular, the paper analytically examines some of the theoretical properties of the residual-based fit statistics with a view to establishing the inferences that can be made using these fit statistics. More specifically, the relationships between the distributional properties of the fit statistics and sample size are discussed; some research that erroneously concludes that residual-based fit statistics are unstable is reviewed; and finally, it is analytically illustrated that, for dichotomous items, residual-based fit statistics provide a measure of the relative slope of empirical item characteristic curves. With a clear understanding of the theoretical properties of the fit statistics, the use and limitations of these statistics can be placed in the right light.


Assuntos
Algoritmos , Coleta de Dados , Interpretação Estatística de Dados , Psicometria , Inquéritos e Questionários , Modelos Estatísticos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
Antioxidants (Basel) ; 11(5)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35624828

RESUMO

Selenium nanoparticles (SeNPs) are a novel elemental form selenium and often reported to possess beneficial bioactivities such as anticancer, promoting bone growth and immunomodulation. Our previous study demonstrated that chitosan-stabilized SeNPs have strong activity in immunomodulation. However, the mechanism underlying the immunomodulation of SeNPs is still unknown. The aim of this study is to identify the molecular mechanisms involved in SeNP-induced immunomodulation. Using zebrafish, as a common immunological animal model with a highly conserved molecular mechanism with other vertebrates, we conducted serum proteomic and tissue transcriptome analyses on individuals fed with SeNP in healthy or disease conditions. We also compared differences between SeNPs and an exogenous antioxidant Trolox in immune activity and redox regulation. Our results suggest that the immunomodulation activity was highly related to antioxidant activity and lipid metabolism. Interestingly, the biological functions enhanced by SeNP were almost identical in the healthy and disease conditions. However, while the SeNP was suppressing ROS in healthy individuals, it promoted ROS formation during disease condition. This might be related to the defense mechanism against pathogens. SOD and NFkß appeared to be the key molecular switch changing effect of SeNPs when individuals undergo infection, indicating the close relationship between immune and redox regulation.

10.
Nat Commun ; 13(1): 942, 2022 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-35177603

RESUMO

Insulin analogs have been developed to treat diabetes with focus primarily on improving the time action profile without affecting ligand-receptor interaction or functional selectivity. As a result, inherent liabilities (e.g. hypoglycemia) of injectable insulin continue to limit the true therapeutic potential of related agents. Insulin dimers were synthesized to investigate whether partial agonism of the insulin receptor (IR) tyrosine kinase is achievable, and to explore the potential for tissue-selective systemic insulin pharmacology. The insulin dimers induced distinct IR conformational changes compared to native monomeric insulin and substrate phosphorylation assays demonstrated partial agonism. Structurally distinct dimers with differences in conjugation sites and linkers were prepared to deliver desirable IR partial agonist (IRPA). Systemic infusions of a B29-B29 dimer in vivo revealed sharp differences compared to native insulin. Suppression of hepatic glucose production and lipolysis were like that attained with regular insulin, albeit with a distinctly shallower dose-response. In contrast, there was highly attenuated stimulation of glucose uptake into muscle. Mechanistic studies indicated that IRPAs exploit tissue differences in receptor density and have additional distinctions pertaining to drug clearance and distribution. The hepato-adipose selective action of IRPAs is a potentially safer approach for treatment of diabetes.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Hipoglicemiantes/farmacologia , Insulina/farmacologia , Receptor de Insulina/agonistas , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Aloxano/administração & dosagem , Aloxano/toxicidade , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Células CHO , Cricetulus , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/induzido quimicamente , Diabetes Mellitus Tipo 1/metabolismo , Células HEK293 , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/uso terapêutico , Lipólise/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Ratos , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Suínos , Porco Miniatura
11.
Clin Rheumatol ; 40(1): 321-330, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32506316

RESUMO

INTRODUCTION/OBJECTIVES: Musculoskeletal ultrasound (MSUS) has been extensively studied by rheumatologists in Europe and the Americas, but less is known about MSUS use in Asia. Our hypothesis is that MSUS use is less prevalent in China as compared with its Western counterparts. This study reports the most up-to-date recommendations for MSUS use in rheumatology globally and is also the first study to characterize the current practices, training, and perceptions regarding MSUS of rheumatologists in China. METHOD: A 43-question survey was designed and distributed via mobile application to members of the Chinese Rheumatology Association, primarily to investigate the current prevalence and utilization of MSUS in China. Statistical analyses included the use of chi-square tests and independent-samples t tests, with p values less than 0.05 considered statistically significant. RESULTS: The results showed low rates of MSUS training (129/528, 24%) and current MSUS use (89/524, 17%) in China. However, there was a high level of interest in learning MSUS, especially among younger respondents. Lack of access to training programs and user variability in skill were seen as significant barriers to the uptake of MSUS. CONCLUSIONS: Despite low rates of MSUS training and utilization, the vast majority of respondents believe that MSUS should become a standard clinical tool in rheumatology, and there was great interest in undergoing training. Importantly, lack of access to MSUS training programs and user variability in skill were seen as significant obstacles to the more widespread use of MSUS, which suggests a need for more standardized, high-quality MSUS training in China. Key Points • A low percentage of Chinese rheumatologists (17%) currently use MSUS. • Chinese rheumatologists expressed a high level of interest in obtaining MSUS training. • The greatest perceived obstacle to more widespread MSUS use is the lack of training programs.


Assuntos
Doenças Musculoesqueléticas , Reumatologia , Ásia , China , Competência Clínica , Europa (Continente) , Humanos , Reumatologistas , Reumatologia/educação , Ultrassonografia
12.
Bioorg Med Chem Lett ; 20(20): 6088-92, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20832306
13.
Clin Cancer Res ; 14(18): 5735-42, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18794082

RESUMO

PURPOSE: For many tumor cells, de novo lipogenesis is a requirement for growth and survival. A considerable body of work suggests that inhibition of this pathway may be a powerful approach to antineoplastic therapy. It has recently been shown that inhibition of various steps in the lipogenic pathway individually can induce apoptosis or loss of viability in tumor cells. However, it is not clear whether quantitative differences exist in the ability of lipogenic enzymes to control tumor cell survival. We present a systematic approach that allows for a direct comparison of the control of lipogenic pathway enzymes over tumor cell growth and apoptosis using different cancer cells. EXPERIMENTAL DESIGN: RNA interference-mediated, graded down-regulation of fatty acid synthase (FAS) pathway enzymes was employed in combination with measurements of lipogenesis, apoptosis, and cell growth. RESULTS: In applying RNA interference titrations to two lipogenic enzymes, acetyl-CoA carboxylase 1 (ACC1) and FAS, we show that ACC1 and FAS both significantly control cell growth and apoptosis in HCT-116 cells. These results also extend to PC-3 and A2780 cancer cells. CONCLUSIONS: Control of tumor cell survival by different steps in de novo lipogenesis can be quantified. Because ACC1 and FAS both significantly control tumor cell growth and apoptosis, we propose that pharmacologic inhibitors of either enzyme might be useful agents in targeting cancer cells that critically rely on fatty acid synthesis. The experimental approach described here may be extended to other targets or disease-relevant pathways to identify steps suitable for therapeutic intervention.


Assuntos
Acetiltransferases/metabolismo , Neoplasias do Colo/enzimologia , Ácido Graxo Sintases/metabolismo , Linhagem Celular , Proliferação de Células , Sobrevivência Celular , Inibidores Enzimáticos/farmacologia , Células HCT116 , Humanos , Lipogênese , Transdução de Sinais , Transfecção
14.
J Appl Meas ; 10(4): 355-70, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19934525

RESUMO

Wu (1997) developed a residual based fit statistic for the generalized Rasch model when marginal maximum likelihood estimation is used. This statistic is based upon a comparison of individual's contributions to the sufficient statistics with the expectation of those contributions, for modeled parameters. In this paper, we present a more flexible approach in which linear combinations of individual's contributions to the sufficient statistics are compared to their expectations. This more flexible approach can be used to test the fit of combinations of items. This article first describes briefly the theoretical derivation of the fit statistics, and then illustrates how user-defined fit tests can be implemented for a number of simulated data sets, and for two real data sets. The results show that user-defined fit tests are much more powerful than fit tests at individual parameter level in testing hypothesized violations of the item response model, such as local dependence and multi-dimensionality.


Assuntos
Funções Verossimilhança , Modelos Teóricos , Psicometria/estatística & dados numéricos , Humanos , Modelos Estatísticos , Inquéritos e Questionários
15.
Mol Metab ; 19: 49-64, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30472415

RESUMO

OBJECTIVES: GPR142, which is highly expressed in pancreatic islets, has recently been deorphanized as a receptor for aromatic amino acids; however, its physiological role and pharmacological potential is unclear. METHODS AND RESULTS: We find that GPR142 is expressed not only in ß- but also in α-cells of the islets as well as in enteroendocrine cells, and we confirm that GPR142 is a highly selective sensor of essential aromatic amino acids, in particular Trp and oligopeptides with N-terminal Trp. GPR142 knock-out mice displayed a very limited metabolic phenotype but demonstrated that L-Trp induced secretion of pancreatic and gut hormones is mediated through GPR142 but that the receptor is not required for protein-induced hormone secretion. A synthetic GPR142 agonist stimulated insulin and glucagon as well as GIP, CCK, and GLP-1 secretion. In particular, GIP secretion was sensitive to oral administration of the GPR142 agonist an effect which in contrast to the other hormones was blocked by protein load. Oral administration of the GPR142 agonist increased [3H]-2-deoxyglucose uptake in muscle and fat depots mediated through insulin action while it lowered liver glycogen conceivably mediated through glucagon, and, consequently, it did not lower total blood glucose. Nevertheless, acute administration of the GPR142 agonist strongly improved oral glucose tolerance in both lean and obese mice as well as Zucker fatty rat. Six weeks in-feed chronic treatment with the GPR142 agonist did not affect body weight in DIO mice, but increased energy expenditure and carbohydrate utilization, lowered basal glucose, and improved insulin sensitivity. CONCLUSIONS: GPR142 functions as a sensor of aromatic amino acids, controlling GIP but also CCK and GLP-1 as well as insulin and glucagon in the pancreas. GPR142 agonists could have novel interesting potential in modifying metabolism through a balanced action of gut hormones as well as both insulin and glucagon.


Assuntos
Ilhotas Pancreáticas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Aminoácidos Aromáticos/metabolismo , Animais , Glicemia/metabolismo , Glucagon/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Células Secretoras de Glucagon/metabolismo , Glucose/metabolismo , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Ratos , Ratos Zucker , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Receptores Acoplados a Proteínas G/biossíntese , Receptores dos Hormônios Gastrointestinais/metabolismo , Receptores de Glucagon/metabolismo , Triptofano/metabolismo
17.
Science ; 365(6451): 386-392, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31273070

RESUMO

Ceramides contribute to the lipotoxicity that underlies diabetes, hepatic steatosis, and heart disease. By genetically engineering mice, we deleted the enzyme dihydroceramide desaturase 1 (DES1), which normally inserts a conserved double bond into the backbone of ceramides and other predominant sphingolipids. Ablation of DES1 from whole animals or tissue-specific deletion in the liver and/or adipose tissue resolved hepatic steatosis and insulin resistance in mice caused by leptin deficiency or obesogenic diets. Mechanistic studies revealed ceramide actions that promoted lipid uptake and storage and impaired glucose utilization, none of which could be recapitulated by (dihydro)ceramides that lacked the critical double bond. These studies suggest that inhibition of DES1 may provide a means of treating hepatic steatosis and metabolic disorders.


Assuntos
Ceramidas/metabolismo , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Resistência à Insulina/genética , Proteínas de Membrana/genética , Oxirredutases/genética , Animais , Ceramidas/química , Ceramidas/genética , Dieta Hiperlipídica/efeitos adversos , Deleção de Genes , Leptina/deficiência , Camundongos , Camundongos Mutantes , Esfingolipídeos/química , Esfingolipídeos/metabolismo
18.
J Clin Invest ; 115(4): 1030-8, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15761499

RESUMO

Effective therapies for the treatment of obesity, a key element of metabolic syndrome, are urgently needed but currently lacking. Stearoyl-CoA desaturase-1 (SCD1) is the rate-limiting enzyme catalyzing the conversion of saturated long-chain fatty acids into monounsaturated fatty acids, which are major components of triglycerides. In the current study, we tested the efficacy of pharmacological inhibition of SCD1 in controlling lipogenesis and body weight in mice. SCD1-specific antisense oligonucleotide inhibitors (ASOs) reduced SCD1 expression, reduced fatty acid synthesis and secretion, and increased fatty acid oxidization in primary mouse hepatocytes. Treatment of mice with SCD1 ASOs resulted in prevention of diet-induced obesity with concomitant reductions in SCD1 expression and the ratio of oleate to stearoyl-CoA in tissues and plasma. These changes correlated with reduced body adiposity, hepatomegaly and steatosis, and postprandial plasma insulin and glucose levels. Furthermore, SCD1 ASOs reduced de novo fatty acid synthesis, decreased expression of lipogenic genes, and increased expression of genes promoting energy expenditure in liver and adipose tissues. Thus, SCD1 inhibition represents a new target for the treatment of obesity and related metabolic disorders.


Assuntos
Obesidade/prevenção & controle , Oligonucleotídeos Antissenso/metabolismo , Estearoil-CoA Dessaturase , Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Animais , Glicemia/metabolismo , Peso Corporal , Células Cultivadas , Dieta , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Insulina/metabolismo , Fígado/citologia , Fígado/enzimologia , Camundongos , Camundongos Endogâmicos , Atividade Motora , Obesidade/metabolismo , Oligonucleotídeos Antissenso/genética , Oxirredução , Consumo de Oxigênio , Estearoil-CoA Dessaturase/antagonistas & inibidores , Estearoil-CoA Dessaturase/genética , Estearoil-CoA Dessaturase/metabolismo
19.
Eur J Pharmacol ; 584(1): 192-201, 2008 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-18346728

RESUMO

The use of the thiazolidinedione insulin sensitizers rosiglitazone and pioglitazone for the treatment of type 2 diabetes mellitus in recent years has proven to be effective in helping patients resume normal glycemic control. However, their use is often associated with undesirable side effects including peripheral edema, congestive heart failure and weight gain. Here, we report the identification and characterization of a novel selective PPARgamma modulator, SPPARgammaM5 ((2S)-2-(2-chloro-5-{[3-(4-chlorophenoxy)-2-methyl-6-(trifluoromethoxy)-1H-indol-1-yl]methyl} phenoxy)propionic acid), which has notable insulin sensitizing properties and a superior tolerability profile to that of rosiglitazone. SPPARgammaM5 is a potent ligand of human PPARgamma with high selectivity versus PPARalpha or PPARdelta in receptor competitive binding assays. In cell-based transcriptional activation assays, SPPARgammaM5 was a potent partial agonist of human PPARgamma in comparison to the PPARgamma full agonist rosiglitazone. Compared to rosiglitazone or the PPARgamma full agonist COOH (2-(2-(4-phenoxy-2-propylphenoxy)ethyl)indole-5-acetic acid), SPPARgammaM5 induced an attenuated PPARgamma-regulated gene expression profile in fully differentiated 3T3-L1 adipocytes and white adipose tissue of chronically treated db/db mice. SPPARgammaM5 treatment also reduced the insulin resistance index by homeostasis model assessment (HOMA), suggesting an improvement in insulin resistance in these db/db mice. Treatment of obese Zucker rats with either rosiglitazone or SPPARgammaM5 resulted in an improvement in selected parameters that serve as surrogate indicators of insulin resistance and hyperlipidemia. However, unlike rosiglitazone, SPPARgammaM5 did not cause significant fluid retention or cardiac hypertrophy in these rats. Thus, compounds such as SPPARgammaM5 may offer beneficial effects on glycemic control with significantly attenuated adverse effects.


Assuntos
Acetatos/farmacologia , Doenças Cardiovasculares/induzido quimicamente , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/farmacologia , Indóis/farmacologia , Resistência à Insulina , PPAR gama/efeitos dos fármacos , Propionatos/farmacologia , Tiazolidinedionas/farmacologia , Células 3T3-L1 , Acetatos/efeitos adversos , Acetatos/metabolismo , Tecido Adiposo Branco/efeitos dos fármacos , Tecido Adiposo Branco/metabolismo , Animais , Células COS , Cardiomegalia/induzido quimicamente , Cardiomegalia/metabolismo , Cardiomegalia/fisiopatologia , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/fisiopatologia , Chlorocebus aethiops , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Agonismo Parcial de Drogas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Hemodiluição , Humanos , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/metabolismo , Indóis/efeitos adversos , Indóis/metabolismo , Resistência à Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos , PPAR alfa/efeitos dos fármacos , PPAR alfa/metabolismo , PPAR delta/efeitos dos fármacos , PPAR delta/metabolismo , PPAR gama/genética , PPAR gama/metabolismo , Propionatos/efeitos adversos , Propionatos/metabolismo , Ligação Proteica , Ratos , Ratos Zucker , Rosiglitazona , Tiazolidinedionas/efeitos adversos , Tiazolidinedionas/metabolismo , Ativação Transcricional/efeitos dos fármacos , Transfecção , Equilíbrio Hidroeletrolítico/efeitos dos fármacos
20.
Bioorg Med Chem Lett ; 18(17): 4798-801, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18701276

RESUMO

A series of highly functionalized 3-aroyl and 3-phenoxy-2-methyl-7-azaindoles have been identified, which are potent selective PPARgamma modulators (SPPARgammaMs). Addition of substituents at the 6-position of the 7-azaindoles improves in vitro potency and pharmacokinetics. 7-Azaindoles have significantly improved off-target profiles compared to the parent indole series.


Assuntos
Indóis/química , Indóis/farmacologia , PPAR gama/metabolismo , Animais , Humanos , Camundongos , PPAR gama/agonistas , Ratos , Ratos Sprague-Dawley
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