RESUMO
Obesity results from a caloric imbalance between energy intake, absorption and expenditure. In both rodents and humans, diet-induced thermogenesis contributes to energy expenditure and involves the activation of brown adipose tissue (BAT). We hypothesize that environmental toxicants commonly used as food additives or pesticides might reduce BAT thermogenesis through suppression of uncoupling protein 1 (UCP1) and this may contribute to the development of obesity. Using a step-wise screening approach, we discover that the organophosphate insecticide chlorpyrifos suppresses UCP1 and mitochondrial respiration in BAT at concentrations as low as 1 pM. In mice housed at thermoneutrality and fed a high-fat diet, chlorpyrifos impairs BAT mitochondrial function and diet-induced thermogenesis, promoting greater obesity, non-alcoholic fatty liver disease (NAFLD) and insulin resistance. This is associated with reductions in cAMP; activation of p38MAPK and AMPK; protein kinases critical for maintaining UCP1 and mitophagy, respectively in BAT. These data indicate that the commonly used pesticide chlorpyrifos, suppresses diet-induced thermogenesis and the activation of BAT, suggesting its use may contribute to the obesity epidemic.
Assuntos
Tecido Adiposo Marrom/fisiopatologia , Clorpirifos/metabolismo , Obesidade/fisiopatologia , Praguicidas/metabolismo , Termogênese/efeitos dos fármacos , Quinases Proteína-Quinases Ativadas por AMP , Animais , Clorpirifos/toxicidade , AMP Cíclico/metabolismo , Metabolismo Energético , Contaminação de Alimentos/análise , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/induzido quimicamente , Obesidade/metabolismo , Praguicidas/toxicidade , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
RNA sequencing (RNA-Seq) is a complicated protocol, both in the laboratory in generation of data and at the computer in analysis of results. Several decisions during RNA-Seq library construction have important implications for analysis, most notably strandedness during complementary DNA library construction. Here, we clarify bioinformatic decisions related to strandedness in both alignment of DNA sequencing reads to reference genomes and subsequent determination of transcript abundance.
