γ-Secretase is an aspartyl intramembranal protease composed of presenilin, Nicastrin, Aph1, and Pen2 with 19 transmembrane domains. γ-Secretase cleaves the amyloid precursor proteins (APP) to release Aβ peptides that likely play a causative role in the pathogenesis of Alzheimer’s disease (AD). In addition, γ-secretase cleaves Notch and other type I membrane proteins. γ-Secretase inhibitors (GSIs) have been developed and used for clinical studies. However, clinical trials have shown adverse effects of GSIs that are potentially linked with nondiscriminatory inhibition of Notch signaling, overall APP processing, and other substrate cleavages. Therefore, these findings call for the development of disease-modifying agents that target γ-secretase activity to lower levels of Aβ42 production without blocking the overall processing of γ-secretase substrates. γ-Secretase modulators (GSMs) originally derived from nonsteroidal anti-inflammatory drugs (NSAIDs) display such characteristics and are the focus of this rev...

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Development and mechanism of γ-secretase modulators for Alzheimer's disease.

The Petasis boron–Mannich reaction, simply referred to as the Petasis reaction, is a powerful multicomponent coupling reaction of a boronic acid, an amine, and a carbonyl derivative. Highly functio...

Reactivity and Synthetic Applications of Multicomponent Petasis Reactions

Recent therapeutic strategies targeting beta amyloid and tauopathies in Alzheimer's disease.

The design and the synthesis of several chemical subclasses of imidazole containing γ-secretase modulators (GSMs) is described. Conformational restriction of pyridone 4 into bicyclic pyridone isosteres has led to compounds with high in vitro and in vivo potency. This has resulted in the identification of benzimidazole 44a as a GSM with low nanomolar potency in vitro. In mouse, rat, and dog, this compound displayed the typical γ-secretase modulatory profile by lowering Aβ42 and Aβ40 levels combined with an especially pronounced increase in Aβ38 and Aβ37 levels while leaving the total levels of amyloid peptides unchanged.

Design and synthesis of a novel series of bicyclic heterocycles as potent γ-secretase modulators.

Introduction: γ-Secretase is the enzyme responsible for the final step of amyloid precursor protein proteolysis to generate Aβ peptides including Aβ42 which is believed to be a toxic species involved in Alzheimer's disease (AD) progression. γ-Secretase modulators (GSMs) have been shown to selectively lower Aβ42 production without affecting total Aβ levels or the formation of γ-secretase substrate intracellular domains such as APP intracellular domain and Notch intracellular domain. Therefore, GSMs have emerged as an important therapeutic strategy for the treatment of AD. Areas covered: The literature covering novel GSMs will be reviewed focusing on patents from 2010 to 2012. Expert opinion: During the last review period (2008 – 2010) considerable progress was made developing GSMs with improved potency for lowering Aβ42 levels, but most of the compounds resided in unfavorable central nervous system (CNS) drug space. In this review period (2010 – 2012), there is a higher percentage of potent GSM chemical ma...

Novel γ-secretase modulators for the treatment of Alzheimer's disease: a review focusing on patents from 2010 to 2012.

We have investigated a novel series of acid-derived γ-secretase modulators as a potential treatment of Alzheimer's disease. Optimization based on cellular potency and brain pharmacodynamics after oral dosing led to the discovery of 10a (BIIB042). Compound 10a is a potent γ-secretase modulator, which lowered Aβ42, increased Aβ38, but had little to no effect on Aβ40 levels both in vitro and in vivo. In addition, compound 10a did not affect Notch signaling in our in vitro assessment. Compound 10a demonstrated excellent pharmacokinetic parameters in multiple species. Oral administration of 10a significantly reduced brain Aβ42 levels in CF-1 mice and Fischer rats, as well as plasma Aβ42 levels in cynomolgus monkeys. Compound 10a was selected as a candidate for preclinical safety evaluation.

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Discovery of BIIB042, a Potent, Selective, and Orally Bioavailable γ-Secretase Modulator.

BIIB042, a novel γ-secretase modulator, reduces amyloidogenic Aβ isoforms in primates and rodents and plaque pathology in a mouse model of Alzheimer's disease

SUMMARY Assemblies of b-amyloid (Ab) peptides are pathological mediators of Alzheimer’s Disease (AD) and are produced by the sequential cleavages of amyloid precursor protein (APP) by b-secretase (BACE1) and g-secretase. The generation of Ab is coupled to neuronal activity, but the molecular basis is unknown. Here, we report that the immediate early gene Arc is required for activity-dependent generation of Ab. Arc is a postsynaptic protein that recruits endophilin2/3 and dynamin to early/recycling endosomes that traffic AMPA receptors to reduce synaptic strength in both Hebbian and non-Hebbian forms of plasticity. The Arc-endosome also traffics APP and BACE1, and Arc physically associates with presenilin1 (PS1) to regulate g-secretase trafficking and confer activity dependence. Genetic deletion of Arc reduces Ab load in a transgenic mouse model of AD. In concert with the finding that patients with AD can express anomalously high levels of Arc, we hypothesize that Arc participates in the pathogenesis of AD.

http://basicmed.med.ncku.edu.tw/public/project/1207-1334311529-1.pdf

Mi-young Jung

Papers

Discovery of BIIB042, a Potent, Selective, and Orally Bioavailable γ-Secretase Modulator.

BIIB042, a novel γ-secretase modulator, reduces amyloidogenic Aβ isoforms in primates and rodents and plaque pathology in a mouse model of Alzheimer's disease

Arc/Arg3.1RegulatesanEndosomalPathway EssentialforActivity-Dependent b-AmyloidGeneration