RESUMO
beta-Site amyloid precursor protein (APP)-cleaving enzyme (BACE) 1 cleavage of amyloid precursor protein is an essential step in the generation of the potentially neurotoxic and amyloidogenic A beta 42 peptides in Alzheimer's disease. Although previous mouse studies have shown brain A beta lowering after BACE1 inhibition, extension of such studies to nonhuman primates or man was precluded by poor potency, brain penetration, and pharmacokinetics of available inhibitors. In this study, a novel tertiary carbinamine BACE1 inhibitor, tertiary carbinamine (TC)-1, was assessed in a unique cisterna magna ported rhesus monkey model, where the temporal dynamics of A beta in cerebrospinal fluid (CSF) and plasma could be evaluated. TC-1, a potent inhibitor (IC(50) approximately 0.4 nM), has excellent passive membrane permeability, low susceptibility to P-glycoprotein transport, and lowered brain A beta levels in a mouse model. Intravenous infusion of TC-1 led to a significant but transient lowering of CSF and plasma A beta levels in conscious rhesus monkeys because it underwent CYP3A4-mediated metabolism. Oral codosing of TC-1 with ritonavir, a potent CYP3A4 inhibitor, twice daily over 3.5 days in rhesus monkeys led to sustained plasma TC-1 exposure and a significant and sustained reduction in CSF sAPP beta, A beta 40, A beta 42, and plasma A beta 40 levels. CSF A beta 42 lowering showed an EC(50) of approximately 20 nM with respect to the CSF [TC-1] levels, demonstrating excellent concordance with its potency in a cell-based assay. These results demonstrate the first in vivo proof of concept of CSF A beta lowering after oral administration of a BACE1 inhibitor in a nonhuman primate.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Precursor de Proteína beta-Amiloide/líquido cefalorraquidiano , Precursor de Proteína beta-Amiloide/antagonistas & inibidores , Animais , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/farmacologia , Humanos , Infusões Intravenosas , Macaca mulatta , Camundongos , Camundongos Transgênicos , TransfecçãoAssuntos
Aminas/química , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Fragmentos de Peptídeos/líquido cefalorraquidiano , Inibidores de Proteases/química , Administração Oral , Aminas/administração & dosagem , Aminas/farmacologia , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Barreira Hematoencefálica , Cristalografia por Raios X , Haplorrinos , Concentração Inibidora 50 , Macaca mulatta , Conformação Molecular , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/farmacologia , Relação Estrutura-AtividadeRESUMO
A series of low-molecular weight 2,6-diamino-isonicotinamide BACE-1 inhibitors containing an amine transition-state isostere were synthesized and shown to be highly potent in both enzymatic and cell-based assays. These inhibitors contain a trans-S,S-methyl cyclopropane P(3) which bind BACE-1 in a 10s-loop down conformation giving rise to highly potent compounds with favorable molecular weight and moderate to high susceptibility to P-glycoprotein (P-gp) efflux.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Niacinamida/síntese química , Niacinamida/farmacologia , Animais , Baculoviridae/efeitos dos fármacos , Baculoviridae/enzimologia , Disponibilidade Biológica , Células Cultivadas , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Peso Molecular , Niacinamida/farmacocinética , Ratos , Relação Estrutura-AtividadeRESUMO
Thrombin-activatable fibrinolysis inhibitor (TAFI) is an important regulator of fibrinolysis, and inhibitors of this enzyme have potential use in antithrombotic and thrombolytic therapy. Appropriately substituted imidazole acetic acids such as 10j were found to be potent inhibitors of activated TAFI and selective versus the related carboxypeptidases CPA, CPN, and CPM but not CPB. Further, 10j accelerated clot lysis in vitro and was shown to be efficacious in a primate model of thrombosis.