RESUMEN
OBJECTIVE: Fibroblast growth factor 21 (FGF21) shows great potential for the treatment of obesity and type 2 diabetes, as its long-acting analogue reduces body weight and improves lipid profiles of participants in clinical studies; however, the intracellular mechanisms mediating these effects are poorly understood. AMP-activated protein kinase (AMPK) is an important energy sensor of the cell and a molecular target for anti-diabetic medications. This work examined the role of AMPK in mediating the glucose and lipid-lowering effects of FGF21. METHODS: Inducible adipocyte AMPK ß1ß2 knockout mice (iß1ß2AKO) and littermate controls were fed a high fat diet (HFD) and treated with native FGF21 or saline for two weeks. Additionally, HFD-fed mice with knock-in mutations on the AMPK phosphorylation sites of acetyl-CoA carboxylase (ACC)1 and ACC2 (DKI mice) along with wild-type (WT) controls received long-acting FGF21 for two weeks. RESULTS: Consistent with previous studies, FGF21 treatment significantly reduced body weight, adiposity, and liver lipids in HFD fed mice. To add, FGF21 improved circulating lipids, glycemic control, and insulin sensitivity. These effects were independent of adipocyte AMPK and were not associated with changes in browning of white (WAT) and brown adipose tissue (BAT). Lastly, we assessed whether FGF21 exerted its effects through the AMPK/ACC axis, which is critical in the therapeutic benefits of the anti-diabetic medication metformin. ACC DKI mice had improved glucose and insulin tolerance and a reduction in body weight, body fat and hepatic steatosis similar to WT mice in response to FGF21 administration. CONCLUSIONS: These data illustrate that the metabolic improvements upon FGF21 administration are independent of adipocyte AMPK, and do not require the inhibitory action of AMPK on ACC. This is in contrast to the anti-diabetic medication metformin and suggests that the treatment of obesity and diabetes with the combination of FGF21 and AMPK activators merits consideration.
Asunto(s)
Acetil-CoA Carboxilasa/metabolismo , Factores de Crecimiento de Fibroblastos/farmacología , Glucosa/metabolismo , Proteínas Quinasas/metabolismo , Quinasas de la Proteína-Quinasa Activada por el AMP , Adipocitos/metabolismo , Animales , Homeostasis , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Ratones , Proteínas Quinasas/genéticaRESUMEN
Tumor cell proliferation and migration processes are regulated by multiple metabolic pathways including glycolysis and de novo lipogenesis. Since acetyl-CoA carboxylase (ACC) is at the junction of lipids synthesis and oxidative metabolic pathways, we investigated whether use of a dual ACC inhibitor would provide a potential therapy against certain lipogenic cancers. The impact of dual ACC1/ACC2 inhibition was investigated using a dual ACC1/ACC2 inhibitor as well as dual siRNA knock down on the cellular viability and metabolism of two glioblastoma multiform cancer cell lines, U87 and a more aggressive form, U87 EGFRvIII. We first demonstrated that while ACCi inhibited DNL in both cell lines, ACCi preferentially blunted the U87 EGFRvIII cellular proliferation capacity. Metabolically, chronic treatment with ACCi significantly upregulated U87 EGFRvIII cellular respiration and extracellular acidification rate, a marker of glycolytic activity, but impaired mitochondrial health by reducing maximal respiration and decreasing mitochondrial ATP production efficiency. Moreover, ACCi treatment altered the cellular lipids content and increased apoptotic caspase activity in U87 EGFRvIII cells. Collectively these data indicate that ACC inhibition, by reducing DNL and increasing cellular metabolic rate, may have therapeutic utility for the suppression of lipogenic tumor growth and warrants further investigation.
Asunto(s)
Acetil-CoA Carboxilasa/antagonistas & inhibidores , Proliferación Celular/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Receptores ErbB , Glioblastoma/tratamiento farmacológico , Glioblastoma/enzimología , Lipogénesis/efectos de los fármacos , Proteínas de Neoplasias/antagonistas & inhibidores , Acetil-CoA Carboxilasa/genética , Acetil-CoA Carboxilasa/metabolismo , Apoptosis/efectos de los fármacos , Apoptosis/genética , Línea Celular Tumoral , Proliferación Celular/genética , Glioblastoma/genética , Glioblastoma/patología , Humanos , Lipogénesis/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Consumo de Oxígeno/efectos de los fármacos , Consumo de Oxígeno/genéticaRESUMEN
Lysophospholipase-like 1 (LYPLAL1) is an uncharacterized metabolic serine hydrolase. Human genome-wide association studies link variants of the gene encoding this enzyme to fat distribution, waist-to-hip ratio, and nonalcoholic fatty liver disease. We describe the discovery of potent and selective covalent small-molecule inhibitors of LYPLAL1 and their use to investigate its role in hepatic metabolism. In hepatocytes, selective inhibition of LYPLAL1 increased glucose production supporting the inference that LYPLAL1 is a significant actor in hepatic metabolism. The results provide an example of how a selective chemical tool can contribute to evaluating a hypothetical target for therapeutic intervention, even in the absence of complete biochemical characterization.
Asunto(s)
Hidrolasas/metabolismo , Lisofosfolipasa/antagonistas & inhibidores , Serina/metabolismo , Animales , Cristalización , Cristalografía por Rayos X , Inhibidores Enzimáticos/farmacología , Humanos , Lisofosfolipasa/químicaRESUMEN
FGF21 plays a central role in energy, lipid, and glucose homeostasis. To characterize the pharmacologic effects of FGF21, we administered a long-acting FGF21 analog, PF-05231023, to obese cynomolgus monkeys. PF-05231023 caused a marked decrease in food intake that led to reduced body weight. To assess the effects of PF-05231023 in humans, we conducted a placebo-controlled, multiple ascending-dose study in overweight/obese subjects with type 2 diabetes. PF-05231023 treatment resulted in a significant decrease in body weight, improved plasma lipoprotein profile, and increased adiponectin levels. Importantly, there were no significant effects of PF-05231023 on glycemic control. PF-05231023 treatment led to dose-dependent changes in multiple markers of bone formation and resorption and elevated insulin-like growth factor 1. The favorable effects of PF-05231023 on body weight support further evaluation of this molecule for the treatment of obesity. Longer studies are needed to assess potential direct effects of FGF21 on bone in humans.
Asunto(s)
Fármacos Antiobesidad/farmacología , Anticuerpos Monoclonales Humanizados/farmacología , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Factores de Crecimiento de Fibroblastos/farmacología , Obesidad/tratamiento farmacológico , Adolescente , Adulto , Anciano , Animales , Fármacos Antiobesidad/uso terapéutico , Anticuerpos Monoclonales Humanizados/uso terapéutico , Glucemia , Peso Corporal/efectos de los fármacos , Diabetes Mellitus Tipo 2/sangre , Evaluación Preclínica de Medicamentos , Femenino , Factores de Crecimiento de Fibroblastos/uso terapéutico , Expresión Génica/efectos de los fármacos , Humanos , Insulina/sangre , Metabolismo de los Lípidos/efectos de los fármacos , Macaca fascicularis , Masculino , Persona de Mediana Edad , Obesidad/sangre , Grasa Subcutánea/efectos de los fármacos , Grasa Subcutánea/metabolismo , Pérdida de Peso , Adulto JovenRESUMEN
Inhibition of the sodium-coupled citrate transporter (NaCT or SLC13A5) has been proposed as a new therapeutic approach for prevention and treatment of metabolic diseases. In a previous report, we discovered dicarboxylate 1a (PF-06649298) which inhibits the transport of citrate in in vitro and in vivo settings via a specific interaction with NaCT. Herein, we report the optimization of this series leading to 4a (PF-06761281), a more potent inhibitor with suitable in vivo pharmacokinetic profile for assessment of in vivo pharmacodynamics. Compound 4a was used to demonstrate dose-dependent inhibition of radioactive [(14)C]citrate uptake in liver and kidney in vivo, resulting in modest reductions in plasma glucose concentrations.
Asunto(s)
Citratos/metabolismo , Malatos/química , Malatos/farmacología , Fenilbutiratos/química , Fenilbutiratos/farmacología , Piridinas/química , Piridinas/farmacología , Simportadores/antagonistas & inhibidores , Animales , Transporte Biológico/efectos de los fármacos , Glucemia/metabolismo , Citratos/farmacocinética , Relación Dosis-Respuesta a Droga , Células HEK293 , Hepatocitos/efectos de los fármacos , Humanos , Riñón/efectos de los fármacos , Riñón/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Malatos/administración & dosificación , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Estructura Molecular , Fenilbutiratos/administración & dosificación , Piridinas/administración & dosificación , Ratas , Ratas Sprague-Dawley , Relación Estructura-Actividad , Simportadores/metabolismoRESUMEN
Citrate is a key regulatory metabolic intermediate as it facilitates the integration of the glycolysis and lipid synthesis pathways. Inhibition of hepatic extracellular citrate uptake, by blocking the sodium-coupled citrate transporter (NaCT or SLC13A5), has been suggested as a potential therapeutic approach to treat metabolic disorders. NaCT transports citrate from the blood into the cell coupled to the transport of sodium ions. The studies herein report the identification and characterization of a novel small dicarboxylate molecule (compound 2) capable of selectively and potently inhibiting citrate transport through NaCT, both in vitro and in vivo. Binding and transport experiments indicate that 2 specifically binds NaCT in a competitive and stereosensitive manner, and is recognized as a substrate for transport by NaCT. The favorable pharmacokinetic properties of 2 permitted in vivo experiments to evaluate the effect of inhibiting hepatic citrate uptake on metabolic endpoints.