P3‐271: Presenilin‐1 (PS1) and amyloid precursor protein (APP) mutations present in mouse models of Alzheimer's disease in their response to γ‐secretase inhibitors and modulators

Presenilin is the molecular target of acidic γ-secretase modulators in living cells.

The intramembrane-cleaving protease γ-secretase catalyzes the last step in the generation of toxic amyloid-β (Aβ) peptides and is a principal therapeutic target in Alzheimer's disease. Both preclinical and clinical studies have demonstrated that inhibition of γ-secretase is associated with prohibitive side effects due to suppression of Notch processing and signaling. Potentially safer are γ-secretase modulators (GSMs), which are small molecules that selectively lower generation of the highly amyloidogenic Aβ42 peptides but spare Notch processing. GSMs with nanomolar potency and favorable pharmacological properties have been described, but the molecular mechanism of GSMs remains uncertain an…

Synthesis of a potent photoreactive acidic γ-secretase modulator for target identification in cells.

Supramolecular self-assembly of amyloidogenic peptides is closely associated with numerous pathological conditions. For instance, Alzheimer´s disease (AD) is characterized by abundant amyloid plaques originating from the proteolytic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. Compounds named γ-secretase modulators (GSMs) can shift the substrate cleavage specificity of γ-secretase toward the production of non-amyloidogenic, shorter Aβ fragments. Herein, we describe the synthesis of highly potent acidic GSMs, equipped with a photoreactive diazirine moiety for photoaffinity labeling. The probes labeled the N-terminal fragment of presenilin (the catalytic subunit of …

Presenilin-1 but not amyloid precursor protein mutations present in mouse models of Alzheimer’s disease attenuate the response of cultured cells to γ-secretase modulators regardless of their potency and structure

γ-Secretase modulators (GSMs) inhibit the generation of amyloidogenic Aβ42 peptides and are promising agents for treatment or prevention of Alzheimer's disease (AD). Recently, a second generation of GSMs with favorable pharmacological properties has emerged, but preclinical studies to assess their efficacy in vivo are lacking. Such studies rely on transgenic mouse models that express amyloid precursor protein (APP) and presenilin (PSEN) mutations associated with early-onset familial AD. Previously, we have shown that certain PSEN1 mutations attenuated the response of cultured cells to GSMs and potentially confound in vivo studies in AD mouse models. However, different combinations of famili…

Discovery of γ-secretase modulators with a novel activity profile by text-based virtual screening.

We present an integrated approach to identify and optimize a novel class of γ-secretase modulators (GSMs) with a unique pharmacological profile. Our strategy included (i) virtual screening through application of a recently developed protocol (PhAST), (ii) synthetic chemistry to discover structure–activity relationships, and (iii) detailed in vitro pharmacological characterization. GSMs are promising agents for treatment or prevention of Alzheimer’s disease. They modulate the γ-secretase product spectrum (i.e., amyloid-β (Aβ) peptides of different length) and induce a shift from toxic Aβ42 to shorter Aβ species such as Aβ38 with no or minimal effect on the overall rate of γ-secretase cleavag…

O1‐11‐06: Presenilin is the molecular target of both acidic and non‐acidic gamma‐secretase modulators