RESUMO
Converging lines of evidence implicate the beta-amyloid peptide (Ass) as causative in Alzheimer's disease. We describe a novel class of compounds that reduce A beta production by functionally inhibiting gamma-secretase, the activity responsible for the carboxy-terminal cleavage required for A beta production. These molecules are active in both 293 HEK cells and neuronal cultures, and exert their effect upon A beta production without affecting protein secretion, most notably in the secreted forms of the amyloid precursor protein (APP). Oral administration of one of these compounds, N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester, to mice transgenic for human APP(V717F) reduces brain levels of Ass in a dose-dependent manner within 3 h. These studies represent the first demonstration of a reduction of brain A beta in vivo. Development of such novel functional gamma-secretase inhibitors will enable a clinical examination of the A beta hypothesis that Ass peptide drives the neuropathology observed in Alzheimer's disease.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Dipeptídeos/administração & dosagem , Endopeptidases/metabolismo , Administração Oral , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/genética , Secretases da Proteína Precursora do Amiloide , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Ácido Aspártico Endopeptidases , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Células Cultivadas , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Endopeptidases/efeitos dos fármacos , Inibidores Enzimáticos/administração & dosagem , Feminino , Humanos , Injeções Subcutâneas , Rim/citologia , Rim/efeitos dos fármacos , Rim/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fragmentos de Peptídeos/metabolismoRESUMO
A series of potent, selective 5HT2B receptor antagonists has been identified based upon yohimbine, with SAR studies resulting in a 1000-fold increase in 5HT2B receptor affinity relative to the starting structure (-log KBS > 10.0 have been obtained). These high-affinity tetrahydro-beta-carboline antagonists are able to discriminate among the 5HT2 family of serotonin receptors, with members of the series showing selectivities of more than 100-fold versus both the 5HT2A and 5HT2C receptors based upon radioligand binding and functional assays. As the first compounds reported with such selectivity and enhanced receptor affinity, these tetrahydro-beta-carboline antagonists are useful tools for elucidating the role of serotonin acting at the 5HT2B receptor in normal and disease physiology.