Γ-secretase Modulators Research Articles

γ-Secretase in the pathogenesis of Alzheimer’s disease and therapeutic potential of its modulators

Alzheimer’s disease is caused by the loss of synaptic connections and neurons in the brain. One of the characteristic morphological features of Alzheimer’s disease is the formation of amyloid plaques containing β-amyloid peptide. The β-amyloid peptide is produced from the amyloid precursor protein (APP) through sequential proteolytic cleavages by α-secretase, β-secretase, and γ-secretase, resulting in β-amyloid peptide clustering into amyloid plaques, a key pathogenic event in Alzheimer’s disease. Since γ-secretase mediates the final cleavage that releases β-amyloid peptide, it has been widely studied as a potential drug target for the treatment of Alzheimer’s disease. γ-Secretase is a transmembrane protein complex consisting of four subunits: presenilin, nicastrin, Aph-1, and Pen-2, which are necessary for its function. γ-Secretase has been shown to cleave more than 140 substrates, including the APP and Notch. Clinical trials of γ-secretase inhibitors for Alzheimer’s disease have shown side effects due to inhibition of Notch signaling. It has been concluded that alternative compounds with more specific regulation or modulation of γ-secretase are needed. A number of γ-secretase modulators have now been developed. To modulate γ-secretase and better understand its complex biology, research focuses on identifying inhibitor and modulator binding sites within γ-secretase’s structure, as well as intermediate binding proteins that modulate γ-secretase. This article discusses recent advances over the past decade in studying the role of γ-secretase in the treatment of Alzheimer’s disease.

Truncated mini LRP1 transports cargo from luminal to basolateral side across the blood brain barrier

BackgroundThe most crucial area to focus on when thinking of novel pathways for drug delivery into the CNS is the blood brain barrier (BBB). A number of nanoparticulate formulations have been shown in earlier research to target receptors at the BBB and transport therapeutics into the CNS. However, no mechanism for CNS entrance and movement throughout the CNS parenchyma has been proposed yet. Here, the truncated mini low-density lipoprotein receptor-related protein 1 mLRP1_DIV* was presented as blood to brain transport carrier, exemplified by antibodies and immunoliposomes using a systematic approach to screen the receptor and its ligands’ route across endothelial cells in vitro.MethodsThe use of mLRP1_DIV* as liposomal carrier into the CNS was validated based on internalization and transport assays across an in vitro model of the BBB using hcMEC/D3 and bEnd.3 cells. Trafficking routes of mLRP1_DIV* and corresponding cargo across endothelial cells were analyzed using immunofluorescence. Modulation of γ-secretase activity by immunoliposomes loaded with the γ-secretase modulator BB25 was investigated in co-cultures of bEnd.3 mLRP1_DIV* cells and CHO cells overexpressing human amyloid precursor protein (APP) and presenilin 1 (PSEN1).ResultsWe showed that while expressed in vitro, mLRP1_DIV* transports both, antibodies and functionalized immunoliposomes from luminal to basolateral side across an in vitro model of the BBB, followed by their mLRP1_DIV* dependent release of the cargo. Importantly, functionalized liposomes loaded with the γ-secretase modulator BB25 were demonstrated to effectively reduce toxic Aß42 peptide levels after mLRP1_DIV* mediated transport across a co-cultured endothelial monolayer.ConclusionTogether, the data strongly suggest mLRP1_DIV* as a promising tool for drug delivery into the CNS, as it allows a straight transport of cargo from luminal to abluminal side across an endothelial monolayer and it’s release into brain parenchyma in vitro, where it exhibits its intended therapeutic effect.

Air pollution amyloidogenesis is attenuated by the gamma-secretase modulator GSM-15606.

Chronic air pollution (AirPoll) is associated with accelerated cognitive decline and risk of Alzheimer's disease (AD). Correspondingly, wild-type and AD-transgenic rodents exposed to AirPoll have increased amyloid peptides and behavioral impairments. We examined the γ-secretase modulator GSM-15606 for potential AirPoll protection by its attenuating of amyloid beta (Aβ)42 peptide production. Male and female wild-type mice were fed GSM-15606 during an 8-week inhalation exposure to AirPoll subfractions, ambient nanoparticulate matter (nPM), and diesel exhaust particles (DEP). GSM-15606 decreased Aβ42 during nPM and DEP exposure without changing beta- or gamma-secretase activity or BACE1 and PS1 protein levels. DEP increased lateral ventricle volume by 25%. These enzyme responses are relevant to AD drug treatments, as well as to the physiological functions of the Aβ42 peptide. GSM-15606 attenuation of Aβ42 may benefit human exposure to AirPoll. Gamma-secretase modulator (GSM-15606) attenuates the amyloidogenic amyloid beta (Aβ)42 peptide during exposure to air pollution, which may be a mechanism by which air pollution increases Alzheimer's disease (AD) risk. AD drug treatments may also consider Aβ homeostasis among the chronic effects of GSM-15606 and other amyloid reduction treatments on secretase enzymes.

Discovery of Clinical Candidate PF-06648671: A Potent γ-Secretase Modulator for the Treatment of Alzheimer's Disease.

Herein, we describe the design and synthesis of γ-secretase modulator (GSM) clinical candidate PF-06648671 (22) for the treatment of Alzheimer's disease. A key component of the design involved a 2,5-cis-tetrahydrofuran (THF) linker to impart conformational rigidity and lock the compound into a putative bioactive conformation. This effort was guided using a pharmacophore model since crystallographic information was not available for the membrane-bound γ-secretase protein complex at the time of this work. PF-06648671 achieved excellent alignment of whole cell in vitro potency (Aβ42 IC50 = 9.8 nM) and absorption, distribution, metabolism, and excretion (ADME) parameters. This resulted in favorable in vivo pharmacokinetic (PK) profile in preclinical species, and PF-06648671 achieved a human PK profile suitable for once-a-day dosing. Furthermore, PF-06648671 was found to have favorable brain availability in rodent, which translated into excellent central exposure in human and robust reduction of amyloid β (Aβ) 42 in cerebrospinal fluid (CSF).

γ-Secretase Modulator BPN15606 Reduced Aβ42 and Aβ40 and Countered Alzheimer-Related Pathologies in a Mouse Model of Down Syndrome.

Due to increased gene dose for the amyloid precursor protein (APP), elderly adults with Down syndrome (DS) are at a markedly increased risk of Alzheimer's disease (AD), known as DS-AD. How the increased APP gene dose acts and which APP products are responsible for DS-AD is not well understood, thus limiting strategies to target pathogenesis. As one approach to address this question, we used a novel class of γ-secretase modulators that promote γ-site cleavages by the γ-secretase complex, resulting in lower levels of the Aβ42 and Aβ40 peptides. Ts65Dn mice, which serve as a model of DS, were treated via oral gavage with 10 mg/kg/weekday of BPN15606 (a potent and novel pyridazine-containing γ-secretase modulators). Treatment started at 3 months-of-age and lasted for 4 months. Demonstrating successful target engagement, treatment with BPN15606 significantly decreased levels of Aβ40 and Aβ42 in the cortex and hippocampus; it had no effect on full-length APP or its C-terminal fragments in either 2 N or Ts65Dn mice. Importantly, the levels of total amyloid-β were not impacted, pointing to BPN15606-mediated enhancement of processivity of γ-secretase. Additionally, BPN15606 rescued hyperactivation of Rab5, a protein responsible for regulating endosome function, and normalized neurotrophin signaling deficits. BPN15606 treatment also normalized the levels of synaptic proteins and tau phosphorylation, while reducing astrocytosis and microgliosis, and countering cognitive deficits. Our findings point to the involvement of increased levels of Aβ42 and/or Aβ40 in contributing to several molecular and cognitive traits associated with DS-AD. They speak to increased dosage of the APP gene acting through heightened levels of Aβ42 and/or Aβ40 as supporting pathogenesis. These findings further the interest in the potential use of γ-secretase modulators for treating and possibly preventing AD in individuals with DS. ANN NEUROL 2024;96:390-404.

How Modulator Binding at the Amyloidβ-γ-Secretase Interface Enhances Substrate Binding and Attenuates Membrane Distortion.

Inhibition of γ-secretase, an intramembrane protease, to reduce secretion of Amyloid-β (Aβ) peptides has been considered for treating Alzheimer's disease. However, γ-secretase inhibitors suffer from severe side effects. As an alternative, γ-secretase modulators (GSM) reduce the generation of toxic peptides by enhancing the cleavage processivity without diminishing the enzyme activity. Starting from a known γ-secretase structure without substrate but in complex with an E2012 GSM, we generated a structural model that included a bound Aβ43 peptide and studied interactions among enzyme, substrate, GSM, and lipids. Our result suggests that E2012 binding at the enzyme-substrate-membrane interface attenuates the membrane distortion by shielding the substrate-membrane interaction. The model predicts that the E2012 modulation is charge-dependent and explains the preserved hydrogen acceptor and the aromatic ring observed in many imidazole-based GSM. Predicted effects of γ-secretase mutations on E2012 modulation were confirmed experimentally. We anticipate that the study will facilitate the future development of effective GSMs.

Sulindac sulfide as a non-immune suppressive γ-secretase modulator to target triple-negative breast cancer.

Triple-negative breast cancer (TNBC) comprises a heterogeneous group of clinically aggressive tumors with high risk of recurrence and metastasis. Current pharmacological treatment options remain largely limited to chemotherapy. Despite promising results, the efficacy of immunotherapy and chemo-immunotherapy in TNBC remains limited. There is strong evidence supporting the involvement of Notch signaling in TNBC progression. Expression of Notch1 and its ligand Jagged1 correlate with poor prognosis. Notch inhibitors, including g-secretase inhibitors (GSIs), are quite effective in preclinical models of TNBC. However, the success of GSIs in clinical trials has been limited by their intestinal toxicity and potential for adverse immunological effects, since Notch plays key roles in T-cell activation, including CD8 T-cells in tumors. Our overarching goal is to replace GSIs with agents that lack their systemic toxicity and ideally, do not affect tumor immunity. We identified sulindac sulfide (SS), the active metabolite of FDA-approved NSAID sulindac, as a potential candidate to replace GSIs. We investigated the pharmacological and immunotherapeutic properties of SS in TNBC models in vitro, ex-vivo and in vivo. We confirmed that SS, a known γ-secretase modulator (GSM), inhibits Notch1 cleavage in TNBC cells. SS significantly inhibited mammosphere growth in all human and murine TNBC models tested. In a transplantable mouse TNBC tumor model (C0321), SS had remarkable single-agent anti-tumor activity and eliminated Notch1 protein expression in tumors. Importantly, SS did not inhibit Notch cleavage in T- cells, and the anti-tumor effects of SS were significantly enhanced when combined with a-PD1 immunotherapy in our TNBC organoids and in vivo. Our data support further investigation of SS for the treatment of TNBC, in conjunction with chemo- or -chemo-immunotherapy. Repurposing an FDA-approved, safe agent for the treatment of TNBC may be a cost-effective, rapidly deployable therapeutic option for a patient population in need of more effective therapies.

2D QSAR STUDY OF FUSED 5,6-BICYCLIC HETEROCYCLES AS ANTI ALZHEIMER’S AGENTS USING TOPOLOGICAL PARAMETERS

Alzheimer’s disease (AD) is a degrading and irreversible neurodegenerative disorder associated with loss of brain functions. It is manifested clinically into psychological symptoms that collectively form cognitive dysfunction and the loss of thinking skills through the progressive degeneration of central nervous system neurons. Over the last decade, γ-secretase emerged as a promising target for the treatment of Alzheimer’s disease. The γ-secretase modulator compounds would be good candidates for AD therapeutics. In previous years, a series fused 5,6-bicyclic heterocycles were investigated as γ-secretase modulators or anti Alzheimer’s agents. In the present study, a quantitative structure activity relationship (QSAR) study of twenty-eight derivatives of fused 5,6-bicyclic heterocycles has been made with the help of topological parameters. The descriptors that have been used are solvent accessible surface area, valence connectivity indices of order 0, 1 and 2 and shape indices of order 1, 2 and 3. The best QSAR model for this set of derivatives has been obtained by using solvent accessible surface area as first descriptor, valence connectivity index (order-0) as second descriptor, valence connectivity index (order-1) as third descriptor and shape index (order-3) as fourth descriptor. The correlation coefficient (r 2 ) and cross validation coefficient (rCV2 ) for this model are 0.773037 and 0.688568, respectively.

Retromer Proteins Reduced in Down Syndrome and the Dp16 Model: Impact of APP Dose and Preclinical Studies of a γ-Secretase Modulator.

The retromer complex plays an essential role in intracellular endosomal sorting. Deficits in the retromer complex are linked to enhanced Aβ production. The levels of the components of the retromer complex are reported to be downregulated in Alzheimer disease (AD). Down syndrome (DS) shares neuropathological features with AD. Recent evidence points to dysregulation of the retromer complex in DS. The mechanisms underlying retromer deficits in DS and AD are poorly understood. We measured the levels of retromer components in the frontal cortex of cases of DS-AD (AD in DS) as well as DS; the frontal cortex of a person partially trisomic (PT-DS) for human chromosome 21 (HSA21), whose genome had only the normal 2 copies of the APP gene, was also examined. We also analyzed these proteins in the Dp16 mouse model of DS. To further explore the molecular mechanism for changes in the retromer complex, we treated Dp16 mice with a γ-secretase modulator (GSM; 776890), a treatment that reduces the levels of Aβ42 and Aβ40. We found VPS26A, VPS26B, and VPS29, but not VPS35, were significantly reduced in both DS and DS-AD, but not in PT-DS. Downregulation of VPS26A, VPS26B, and VPS29 was recapitulated in the brains of old Dp16 mice (at 16 months of age) and required increased App gene dose. Significantly, GSM treatment completely prevented reductions of the retromer complex. Our studies point to increased APP gene dose as a compromising retromer function in DS and suggest a causal role for Aβ42 and Aβ40. ANN NEUROL 2023;94:245-258.

An internal docking site stabilizes substrate binding to γ-secretase: Analysis by molecular dynamics simulations

Amyloid precursor protein (APP) is cleaved and processed sequentially by γ-secretase yielding amyloid β (Aβ) peptides of different lengths. Longer Aβ peptides are associated with the formation of neurotoxic plaques related to Alzheimer’s disease. Based on the APP substrate-bound structure of γ-secretase, we investigated the enzyme-substrate interaction using molecular dynamics simulations and generated model structures that represent the sequentially cleaved intermediates during the processing reaction. The simulations indicated an internal docking site providing strong enzyme-substrate packing interaction. In the enzyme-substrate complex, it is located close to the region where the helical conformation of the substrate is interrupted and continues toward the active site in an extended conformation. The internal docking site consists of two non-polar pockets that are preferentially filled by large hydrophobic or aromatic substrate side chains to stabilize binding. Placement of smaller residues such as glycine can trigger a shift in the cleavage pattern during the simulations or results in destabilization of substrate binding. The reduced packing by smaller residues also influences the hydration of the active site and the formation of a catalytically active state. The simulations on processed substrate intermediates and a substrate G33I mutation offer an explanation of the experimentally observed relative increase of short Aβ fragment production for this mutation. In addition, studies on a substrate K28A mutation indicate that the internal docking site opposes the tendency of substrate dissociation due to a hydrophobic mismatch at the membrane boundary caused by K28 during processing and substrate movement toward the enzyme active site. The proposed internal docking site could also be useful for the specific design of new γ-secretase modulators.

γ-Secretase in Alzheimer's disease.

Alzheimer’s disease (AD) is caused by synaptic and neuronal loss in the brain. One of the characteristic hallmarks of AD is senile plaques containing amyloid β-peptide (Aβ). Aβ is produced from amyloid precursor protein (APP) by sequential proteolytic cleavages by β-secretase and γ-secretase, and the polymerization of Aβ into amyloid plaques is thought to be a key pathogenic event in AD. Since γ-secretase mediates the final cleavage that liberates Aβ, γ-secretase has been widely studied as a potential drug target for the treatment of AD. γ-Secretase is a transmembrane protein complex containing presenilin, nicastrin, Aph-1, and Pen-2, which are sufficient for γ-secretase activity. γ-Secretase cleaves >140 substrates, including APP and Notch. Previously, γ-secretase inhibitors (GSIs) were shown to cause side effects in clinical trials due to the inhibition of Notch signaling. Therefore, more specific regulation or modulation of γ-secretase is needed. In recent years, γ-secretase modulators (GSMs) have been developed. To modulate γ-secretase and to understand its complex biology, finding the binding sites of GSIs and GSMs on γ-secretase as well as identifying transiently binding γ-secretase modulatory proteins have been of great interest. In this review, decades of findings on γ-secretase in AD are discussed.

A Matter of Timing: Rudy Tanzi on Alzheimer's Disease

A Matter of Timing: Rudy Tanzi on Alzheimer's Disease

ENANTIOSELECTIVE SYNTHESIS OF (S)-(-)-1-(4-FLUOROPHENYL)ETHANOL

S)-(–)-1-(4-Fluorophenyl)ethanolis an intermediate in the synthesis of an antagonist of the CCR5 chemokine receptor that can be protective against HIV infection. Along with o-fluoro-substituted analogs, (S)-(–)-1-(4-fluorophenyl)ethanol can be used to study the role of substituents in the chiral recognition of molecular complexes, and (R)-(+)-1-(4-fluorophenyl)ethanol is a com-ponent of an antimalarial drug and a γ-secretase modulator necessary for the treatment of Alzhei-mer's disease.We proposed an approach to the synthesis of (S)-(-)-1-(4-fluorophenyl)ethanol based on the enantioselective reduction of prochiral 1-(4-fluorophenyl)ethanone catalyzed by Daucus carota cells. We found the conditions that make it possible to obtain (S)-(–)-1-(4-fluorophenyl)eth-anol by bioreduction of 1-(4-fluorophenyl)ethanone in the presence of a D. carota biocatalyst for 48 h with 55% yield (98% ee).We also studied the possibility of optimizing the transformation of 1-(4-fluorophenyl)ethanone in a reaction medium containing various exogenous reducing agents(ethanol, isopropanol, or glucose), which are known to significantly affect the product yield and the enantioselectivity of the process. Biotransformation of 1-(4-fluorophenyl)ethanone in the pres-ence of ethanol (1-5%) gives (S)-(-)-1-(4-fluorophenyl)ethanol with 7-85% yields and optical purity 10-98% ee.Enantioselective reduction of the initial ketone in the presence of isopropanol (1-5%) does not lead to a significant increase in the yield and optical purity of S-alcohol (7-57% (18-98% ee).In the case of biotransformation of 1-(4-fluorophenyl)ethanone in the presence of an equimo-lar amount of glucosefor 48 hthe yield of (S)-(-)-1-(4-fluorophenyl)ethanol is 66% (98% ee).Fur-ther transformation of the initial ketone (144 h) both in the absence of an exogenous reducing agent and in the presence of an equimolar amount of glucose leads to an increase in the yield of alcohol to 73% and 76%, respectively, however, the optical purity of the alcohol decreases to 62% ee and 80% ee, which suggests the stereoinversion.

Evaluation of Virtual Screening Strategies for the Identification of γ-Secretase Inhibitors and Modulators.

γ-Secretase is an intramembrane aspartyl protease that is important in regulating normal cell physiology via cleavage of over 100 transmembrane proteins, including Amyloid Precursor Protein (APP) and Notch family receptors. However, aberrant proteolysis of substrates has implications in the progression of disease pathologies, including Alzheimer’s disease (AD), cancers, and skin disorders. While several γ-secretase inhibitors have been identified, there has been toxicity observed in clinical trials associated with non-selective enzyme inhibition. To address this, γ-secretase modulators have been identified and pursued as more selective agents. Recent structural evidence has provided an insight into how γ-secretase inhibitors and modulators are recognized by γ-secretase, providing a platform for rational drug design targeting this protease. In this study, docking- and pharmacophore-based screening approaches were evaluated for their ability to identify, from libraries of known inhibitors and modulators with decoys with similar physicochemical properties, γ-secretase inhibitors and modulators. Using these libraries, we defined strategies for identifying both γ-secretase inhibitors and modulators incorporating an initial pharmacophore-based screen followed by a docking-based screen, with each strategy employing distinct γ-secretase structures. Furthermore, known γ-secretase inhibitors and modulators were able to be identified from an external set of bioactive molecules following application of the derived screening strategies. The approaches described herein will inform the discovery of novel small molecules targeting γ-secretase.

γ-Secretase modulators show selectivity for γ-secretase-mediated amyloid precursor protein intramembrane processing.

The aggregation of β‐amyloid peptide 42 results in the formation of toxic oligomers and plaques, which plays a pivotal role in Alzheimer's disease pathogenesis. Aβ42 is one of several Aβ peptides, all of Aβ30 to Aβ43 that are produced as a result of γ‐secretase–mediated regulated intramembrane proteolysis of the amyloid precursor protein. γ‐Secretase modulators (GSMs) represent a promising class of Aβ42‐lowering anti‐amyloidogenic compounds for the treatment of AD. Gamma‐secretase modulators change the relative proportion of secreted Aβ peptides, while sparing the γ‐secretase–mediated processing event resulting in the release of the cytoplasmic APP intracellular domain. In this study, we have characterized how GSMs affect the γ‐secretase cleavage of three γ‐secretase substrates, E‐cadherin, ephrin type A receptor 4 (EphA4) and ephrin type B receptor 2 (EphB2), which all are implicated in important contexts of cell signalling. By using a reporter gene assay, we demonstrate that the γ‐secretase–dependent generation of EphA4 and EphB2 intracellular domains is unaffected by GSMs. We also show that γ‐secretase processing of EphA4 and EphB2 results in the release of several Aβ‐like peptides, but that only the production of Aβ‐like proteins from EphA4 is modulated by GSMs, but with an order of magnitude lower potency as compared to Aβ modulation. Collectively, these results suggest that GSMs are selective for γ‐secretase–mediated Aβ production.

Discovery of aryl aminothiazole γ-secretase modulators with novel effects on amyloid β-peptide production

A series of analogs based on a prototype aryl aminothiazole γ-secretase modulator (GSM) were synthesized and tested for their effects on the profile of 37-to-42-residue amyloid β-peptides (Aβ), generated through processive proteolysis of precursor protein substrate by γ-secretase. Certain substitutions on the terminal aryl D ring resulted in an altered profile of Aβ production compared to that seen with the parent molecule. Small structural changes led to concentration-dependent increases in Aβ37 and Aβ38 production without parallel decreases in their precursors Aβ40 and Aβ42, respectively. The new compounds therefore apparently also stimulate carboxypeptidase trimming of Aβ peptides ≥ 43 residues, providing novel chemical tools for mechanistic studies of processive proteolysis by γ-secretase.

A Local Desymmetrization Approach to Piperidinyl Acetic Acid γ-Secretase Modulators.

A desymmetrization-based approach for the synthesis of piperidinyl acetic acid γ-secretase modulators has been developed. The synthetic sequence features the use of N-tert-butanesulfinyl imine reduction and a diastereoselective lactam formation to set up the chiral centers. The synthetic utility is demonstrated by the concise asymmetric synthesis of γ-secretase modulator GSM-1.

FYN, SARS-CoV-2, and IFITM3 in the neurobiology of Alzheimer's disease

Introduction(IFITM3) is an innate immune protein that has been identified as a novel γ-secretase (γs) modulator. FYN is a kinase that stabilizes IFITM3 on the membrane, primes APP for amyloidogenic γs processing and mediates tau oligomerization. The purpose of this study is to explore the role of FYN and IFITM3 in AD and COVID-19, expanding on previous research from our group. MethodsA 520 gene signature containing FYN and IFITM3 (termed Ia) was extracted from a previously published meta-analysis of Alzheimer's disease (AD) bulk- and single nuclei sequencing data. Exploratory analyses involved meta-analysis of bulk and single cell RNA data for IFITM3 and FYN differential expression per CNS site and cellular type. Confirmatory analyses, gene set enrichment analysis (GSEA) on Ia was performed to detect overlapping enriched biological networks between COVID-19 with AD. ResultsBulk RNA data analysis revealed that IFITM3 and FYN were overexpressed in two CNS regions in AD vs. Controls: the temporal cortex Wilcoxon p-value=1.3e-6) and the parahippocampal cortex Wilcoxon p-value=0.012). Correspondingly, single cell RNA analysis of IFITM3 and FYN revealed that it was differentially expressed in neurons, glial and endothelial cells donated b AD patients, when compared to controls. DiscussionIFITM3 and FYN were found as interactors within biological networks overlapping between AD and SARS-CoV-2 infection. Within the context of SARS-CoV-2 induced tau aggregation and interactions between tau and Ab1–42, the FYN – IFITM3 regulome may outline an important innate immunity element responsive to viral infection and IFN-I signaling in both AD and COVID-19.

Contribution to the Discovery of a Novel Medicine for a Neuromuscular Disease and of other Promising Molecules for the Treatment of Neurodevelopmental and Neurodegenerative Diseases.

Nervous system disorders affect millions of people around the world, through a very broad range of diseases. Here we describe our contribution to find a treatment for patients suffering from three of those diseases. The first one, autism spectrum disorder (ASD), affects approximately one in every 59 children in US. The second one, spinal muscular atrophy (SMA) is a rare disease affecting 1 in 10000 live births worldwide, often leading to death if untreated. The third one, Alzheimer's disease (AD) is a very well known devastating disease with an estimated 50 million people living with AD and other dementia, a number expected to triple by 2050. Our strategy to address those diseases was directed towards the discovery of a selective vasopressin 1a (V1a) antagonist for ASD, a splicing modifier of the survival of motor neuron 2 (SMN2) for SMA, and finally a γ-secretase modulator (GSM) for AD. In the frame of our GSM project, we also reported the discovery of a bridge piperidine moiety as a bioisostere for a phenyl moiety with an improved drug-like profile.

Characterizing the Chemical Space of γ-Secretase Inhibitors and Modulators

γ-Secretase (GS) is one of the most attractive molecular targets for the treatment of Alzheimer's disease (AD). Its key role in the final step of amyloid-β peptides generation and its relationship in the cascade of events for disease development have caught the attention of many pharmaceutical groups. Over the past years, different inhibitors and modulators have been evaluated as promising therapeutics against AD. However, despite the great chemical diversity of the reported compounds, a global classification and visual representation of the chemical space for GS inhibitors and modulators remain unavailable. In the present work, we carried out a two-dimensional (2D) chemical space analysis from different classes and subclasses of GS inhibitors and modulators based on their structural similarity. Along with the novel structural information available for GS complexes, our analysis opens the possibility to identify compounds with high molecular similarity, critical to finding new chemical structures through the optimization of existing compounds and relating them with a potential binding site.