RESUMO
Identification and validation of novel drug targets continues to be a major bottleneck in drug development, particularly for polygenic complex diseases such as type 2 diabetes. Here, the authors describe an approach that allows researchers to rapidly identify and validate potential drug targets by combining chemical tools and RNA interference technology. As a proof-of-concept study, the known mechanism Sigma LOPAC library was used to screen for glucose-dependent insulin secretion (GDIS) in INS-1 832/13 cells. In addition to several mechanisms that are known to regulate GDIS (such as cyclic adenosine monophosphate-specific phosphodiesterases, adrenoceptors, and Ca(2+) channels), the authors find that several of the dopamine receptor (DRD) antagonists significantly enhance GDIS, whereas DRD agonists profoundly inhibit GDIS. Subsequent siRNA studies in the same cell line indicate that knockdown of DRD2 enhanced GDIS. Furthermore, selective DRD2 antagonists and agonists also enhance or suppress, respectively, GDIS in isolated rat islets. The data support that the approach described here offers a rapid and effective way for target identification and validation.
Assuntos
Biblioteca Gênica , Inativação Gênica , Glucose/farmacologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Redes e Vias Metabólicas/genética , RNA Interferente Pequeno/farmacologia , Animais , Células Cultivadas , Antagonistas de Dopamina/farmacologia , Inativação Gênica/fisiologia , Secreção de Insulina , Redes e Vias Metabólicas/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Dopaminérgicos/genética , Receptores Dopaminérgicos/metabolismoRESUMO
Five G-protein-coupled melanocortin receptors (MC(1)-MC(5)) are expressed in mammalian tissues. The melanocortin receptors support diverse physiological functions, including the regulation of hair color, adrenal function, energy homeostasis, feed efficiency, sebaceous gland lipid production and immune and sexual function. The melanocortins (adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-MSH and gamma-MSH) are agonist peptide ligands for the melanocortin receptors and these peptides are processed from the pre-prohormone proopiomelanocortin (POMC). Peptide antagonists for the melanocortin MC(1), MC(3) and MC(4) receptors include agouti-related protein (AgRP) and agouti. Diverse lines of evidence, including genetic and pharmacological data obtained in rodents and humans, support a role for the melanocortin MC(3) and MC(4) receptors in the regulation of energy homeostasis. Recent advances in the development of potent and selective peptide and non-peptide melanocortin receptor ligands are anticipated to help unravel the roles for the melanocortin receptors in humans and to accelerate the clinical use of small molecule melanocortin mimetics.
Assuntos
Peso Corporal/fisiologia , Hormônios Estimuladores de Melanócitos/fisiologia , Obesidade/fisiopatologia , Animais , Fármacos Antiobesidade/química , Fármacos Antiobesidade/uso terapêutico , Peso Corporal/efeitos dos fármacos , Expressão Gênica , Humanos , Hormônios Estimuladores de Melanócitos/genética , Obesidade/tratamento farmacológico , Receptores da Corticotropina/efeitos dos fármacos , Receptores da Corticotropina/genética , Receptores da Corticotropina/fisiologia , Receptores de MelanocortinaRESUMO
Five G-protein-coupled melanocortin receptors (MC(1)-MC(5)) are expressed in mammalian tissues. The melanocortin receptors support diverse physiological functions, including the regulation of hair color, adrenal function, energy homeostasis, feed efficiency, sebaceous gland lipid production and immune and sexual function. The melanocortins (adrenocorticotropic hormone (ACTH), alpha-melanocyte-stimulating hormone (alpha-MSH), beta-MSH and gamma-MSH) are agonist peptide ligands for the melanocortin receptors and these peptides are processed from the pre-prohormone proopiomelanocortin (POMC). Peptide antagonists for the melanocortin MC(1), MC(3) and MC(4) receptors include agouti-related protein (AgRP) and agouti. Diverse lines of evidence, including genetic and pharmacological data obtained in rodents and humans, support a role for the melanocortin MC(3) and MC(4) receptors in the regulation of energy homeostasis. Recent advances in the development of potent and selective peptide and non-peptide melanocortin receptor ligands are anticipated to help unravel the roles for the melanocortin receptors in humans and to accelerate the clinical use of small molecule melanocortin mimetics.
