RESUMO
A functional high throughput screen identified a novel chemotype for the positive allosteric modulation (PAM) of the muscarinic acetylcholine receptor (mAChR) subtype 5 (M5). Application of rapid analog, iterative parallel synthesis efficiently optimized M5 potency to arrive at the most potent M5 PAMs prepared to date and provided tool compound 8n (ML380) demonstrating modest CNS penetration (human M5 EC50 = 190 nM, rat M5 EC50 = 610 nM, brain to plasma ratio (Kp) of 0.36).
Assuntos
Sistema Nervoso Central/metabolismo , Descoberta de Drogas , Indazóis/metabolismo , Indazóis/farmacologia , Piperidinas/metabolismo , Piperidinas/farmacologia , Receptor Muscarínico M5/química , Receptor Muscarínico M5/metabolismo , Sulfonamidas/metabolismo , Sulfonamidas/farmacologia , Regulação Alostérica/efeitos dos fármacos , Animais , Avaliação Pré-Clínica de Medicamentos , Ensaios de Triagem em Larga Escala , Humanos , Indazóis/química , Indazóis/farmacocinética , Masculino , Piperidinas/química , Piperidinas/farmacocinética , Ratos , Especificidade por Substrato , Sulfonamidas/química , Sulfonamidas/farmacocinéticaRESUMO
Of the five G-protein-coupled muscarinic acetylcholine receptors (mAChRs; M1-M5), M5 is the least explored and understood due to a lack of mAChR subtype-selective ligands. We recently performed a high-throughput functional screen and identified a number of weak antagonist hits that are selective for the M5 receptor. Here, we report an iterative parallel synthesis and detailed molecular pharmacologic profiling effort that led to the discovery of the first highly selective, central nervous system (CNS)-penetrant M5-orthosteric antagonist, with sub-micromolar potency (hM5 IC50=450â nM, hM5 Ki=340â nM, M1-M4 IC50>30â µM), enantiospecific inhibition, and an acceptable drug metabolism and pharmacokinetics (DMPK) profile for in vitro and electrophysiology studies. This compound will be a powerful tool and molecular probe for the further investigation into the role of M5 in addiction and other diseases.
Assuntos
Acetofenonas/química , Isoxazóis/química , Sondas Moleculares/química , Antagonistas Muscarínicos/química , Receptor Muscarínico M5/antagonistas & inibidores , Acetofenonas/metabolismo , Acetofenonas/farmacocinética , Animais , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Isoxazóis/metabolismo , Isoxazóis/farmacocinética , Sondas Moleculares/metabolismo , Sondas Moleculares/farmacocinética , Antagonistas Muscarínicos/metabolismo , Antagonistas Muscarínicos/farmacocinética , Ligação Proteica , Ratos , Receptor Muscarínico M5/metabolismoRESUMO
A functional high throughput screen and subsequent multidimensional, iterative parallel synthesis effort identified the first muscarinic acetylcholine receptor (mAChR) negative allosteric modulator (NAM) selective for the M5 subtype. ML375 is a highly selective M5 NAM with submicromolar potency (human M5 IC50 = 300 nM, rat M5 IC50 = 790 nM, M1-M4 IC50 > 30 µM), excellent multispecies PK, high CNS penetration, and enantiospecific inhibition.
Assuntos
Encéfalo/metabolismo , Descoberta de Drogas , Imidazóis/química , Imidazóis/farmacologia , Indóis/química , Indóis/farmacologia , Receptor Muscarínico M5/metabolismo , Regulação Alostérica/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Células CHO , Cricetinae , Cricetulus , Avaliação Pré-Clínica de Medicamentos , Humanos , Imidazóis/metabolismo , Imidazóis/farmacocinética , Indóis/metabolismo , Indóis/farmacocinética , Masculino , Ratos , Receptor Muscarínico M5/química , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
The therapeutic potential of small molecule signaling inhibitors is often limited by off-target effects. Recently, in a screen for compounds that perturb the zebrafish embryonic dorsoventral axis, we identified dorsomorphin, the first selective inhibitor of bone morphogenetic protein (BMP) signaling. Here we show that dorsomorphin has significant "off-target" effects against the VEGF (vascular endothelial growth factor) type-2 receptor (Flk1/KDR) and disrupts zebrafish angiogenesis. Since both BMP and VEGF signals are known to be involved in vascular development, we sought to determine whether dorsomorphin's antiangiogenic effects are due to its impact on the BMP or VEGF signals through the development of analogues that target BMP but not VEGF signaling and vice versa. In a structure-activity relationship (SAR) study of dorsomorphin analogues based primarily on their effects on live zebrafish embryos, we identified highly selective and potent BMP inhibitors as well as selective VEGF inhibitors. One of the BMP inhibitors, DMH1, which exclusively targets the BMP but not the VEGF pathway, dorsalized the embryonic axis without disrupting the angiogenic process, demonstrating that BMP signaling was not involved in the angiogenic process. This is one of the first full-scale SAR studies performed in vertebrates and demonstrates the potential of zebrafish as an attractive complementary platform for drug development that incorporates an assessment of in vivo bioactivity and selectivity in the context of a living organism.