sulindac and Alzheimer-Disease

Topics: Aged; Alzheimer Disease; Animals; Anti-Inflammatory Agents, Non-Steroidal; Humans; Ibuprofen; Indomethacin; Mice; Sulindac

Transthyretin (TTR) has a well-established role in neuroprotection in Alzheimer's Disease (AD). We have setup a drug discovery program of small-molecule compounds that act as chaperones enhancing TTR/Amyloid-beta peptide (Aβ) interactions. A combination of computational drug repurposing approaches and in vitro biological assays have resulted in a set of molecules which were then screened with our in-house validated high-throughput screening ternary test. A prioritized list of chaperones was obtained and corroborated with ITC studies. Small-molecule chaperones have been discovered, among them our lead compound Iododiflunisal (IDIF), a molecule in the discovery phase; one investigational drug (luteolin); and 3 marketed drugs (sulindac, olsalazine and flufenamic), which could be directly repurposed or repositioned for clinical use. Not all TTR tetramer stabilizers behave as chaperones in vitro. These chemically diverse chaperones will be used for validating TTR as a target in vivo, and to select one repurposed drug as a candidate to enter clinical trials as AD disease-modifying drug.

Topics: Alzheimer Disease; Calorimetry; Dose-Response Relationship, Drug; Drug Discovery; Humans; Models, Molecular; Molecular Chaperones; Molecular Structure; Prealbumin; Small Molecule Libraries; Software; Structure-Activity Relationship

Alzheimer's disease is characterized by deposition of the amyloid β-peptide (Aβ) in brain tissue of affected individuals. In recent years, many potential lead structures have been suggested that can potentially be used for diagnosis and therapy. However, the mode of action of these compounds is so far not understood. Among these small molecules, the nonsteroidal anti-inflammatory drug (NSAID) sulindac sulfide received a lot of attention. In this manuscript, we characterize the interaction between the monomeric Aβ peptide and the NSAID sulindac sulfide. We find that sulindac sulfide efficiently depletes the pool of toxic oligomers by enhancing the rate of fibril formation. In vitro, sulindac sulfide forms colloidal particles which catalyze the formation of fibrils. Aggregation is immediate, presumably by perturbing the supersaturated Aβ solution. We find that sulindac sulfide induced Aβ aggregates are structurally homogeneous. The C-terminal part of the peptide adopts a β-sheet structure, whereas the N-terminus is disordered. The salt bridge between D23 and K28 is present, similar as in wild type fibril structures. (13)C-(19)F transferred echo double resonance experiments suggest that sulindac sulfide colocalizes with the Aβ peptide in the aggregate.

Topics: Alzheimer Disease; Amino Acid Sequence; Amyloid beta-Peptides; Anti-Inflammatory Agents, Non-Steroidal; Cell Line, Tumor; Dose-Response Relationship, Drug; Humans; Molecular Sequence Data; Peptide Fragments; Protein Aggregates; Sulindac

Alzheimer disease is the most severe neurodegenerative disease worldwide. In the past years, a plethora of small molecules interfering with amyloid-β (Aβ) aggregation has been reported. However, their mode of interaction with amyloid fibers is not understood. Non-steroidal anti-inflammatory drugs (NSAIDs) are known γ-secretase modulators; they influence Aβ populations. It has been suggested that NSAIDs are pleiotrophic and can interact with more than one pathomechanism. Here we present a magic angle spinning solid-state NMR study demonstrating that the NSAID sulindac sulfide interacts specifically with Alzheimer disease Aβ fibrils. We find that sulindac sulfide does not induce drastic architectural changes in the fibrillar structure but intercalates between the two β-strands of the amyloid fibril and binds to hydrophobic cavities, which are found consistently in all analyzed structures. The characteristic Asp(23)-Lys(28) salt bridge is not affected upon interacting with sulindac sulfide. The primary binding site is located in the vicinity of residue Gly(33), a residue involved in Met(35) oxidation. The results presented here will assist the search for pharmacologically active molecules that can potentially be employed as lead structures to guide the design of small molecules for the treatment of Alzheimer disease.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Anti-Inflammatory Agents, Non-Steroidal; Humans; Hydrophobic and Hydrophilic Interactions; Magnetic Resonance Spectroscopy; Protein Binding; Protein Structure, Secondary; Sulindac

Alzheimer's disease (AD) is characterized by extensive loss of neurons in the brain of AD patients. Intracellular accumulation of beta-amyloid peptide (Abeta) has also shown to occur in AD. Neuro-inflammation has been known to play a role in the pathogenesis of AD.. In this study, we investigated neuro-inflammation and amyloidogenesis and memory impairment following the systemic inflammation generated by lipopolysaccharide (LPS) using immunohistochemistry, ELISA, behavioral tests and Western blotting.. Intraperitoneal injection of LPS, (250 microg/kg) induced memory impairment determined by passive avoidance and water maze tests in mice. Repeated injection of LPS (250 microg/kg, 3 or 7 times) resulted in an accumulation of Abeta1-42 in the hippocampus and cerebralcortex of mice brains through increased beta- and gamma-secretase activities accompanied with the increased expression of amyloid precursor protein (APP), 99-residue carboxy-terminal fragment of APP (C99) and generation of Abeta1-42 as well as activation of astrocytes in vivo. 3 weeks of pretreatment of sulindac sulfide (3.75 and 7.5 mg/kg, orally), an anti-inflammatory agent, suppressed the LPS-induced amyloidogenesis, memory dysfunction as well as neuronal cell death in vivo. Sulindac sulfide (12.5-50 microM) also suppressed LPS (1 microg/ml)-induced amyloidogenesis in cultured neurons and astrocytes in vitro.. This study suggests that neuro-inflammatory reaction could contribute to AD pathology, and anti-inflammatory agent could be useful for the prevention of AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Anti-Inflammatory Agents, Non-Steroidal; Behavior, Animal; Brain; Cells, Cultured; Cognition Disorders; Female; Humans; Inflammation; Isoenzymes; Learning; Lipopolysaccharides; Male; Memory Disorders; Mice; Neurons; Pregnancy; Random Allocation; Rats; Rats, Sprague-Dawley; Sulindac

The enzyme gamma-secretase has long been considered a potential pharmaceutical target for Alzheimer disease. Presenilin (the catalytic subunit of gamma-secretase) and signal peptide peptidase (SPP) are related transmembrane aspartyl proteases that cleave transmembrane substrates. SPP and gamma-secretase are pharmacologically similar in that they are targeted by many of the same small molecules, including transition state analogs, non-transition state inhibitors, and amyloid beta-peptide modulators. One difference between presenilin and SPP is that the proteolytic activity of presenilin functions only within a multisubunit complex, whereas SPP requires no additional protein cofactors for activity. In this study, gamma-secretase inhibitor radioligands were used to evaluate SPP and gamma-secretase inhibitor binding pharmacology. We found that the SPP enzyme exhibited distinct binding sites for transition state analogs, non-transition state inhibitors, and the nonsteroidal anti-inflammatory drug sulindac sulfide, analogous to those reported previously for gamma-secretase. In the course of this study, cultured cells were found to contain an abundance of SPP binding activity, most likely contributed by several of the SPP family proteins. The number of SPP binding sites was in excess of gamma-secretase binding sites, making it essential to use selective radioligands for evaluation of gamma-secretase binding under these conditions. This study provides further support for the idea that SPP is a useful model of inhibitory mechanisms and structure in the SPP/presenilin protein family.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid Precursor Protein Secretases; Anti-Inflammatory Agents, Non-Steroidal; Aspartic Acid Endopeptidases; Binding Sites; Catalytic Domain; Cell Line; Humans; Ligands; Models, Molecular; Presenilins; Protease Inhibitors; Sulindac

Epidemiological studies have documented a reduced prevalence of Alzheimer's disease among users of nonsteroidal anti-inflammatory drugs (NSAIDs). It has been proposed that NSAIDs exert their beneficial effects in part by reducing neurotoxic inflammatory responses in the brain, although this mechanism has not been proved. Here we report that the NSAIDs ibuprofen, indomethacin and sulindac sulphide preferentially decrease the highly amyloidogenic Abeta42 peptide (the 42-residue isoform of the amyloid-beta peptide) produced from a variety of cultured cells by as much as 80%. This effect was not seen in all NSAIDs and seems not to be mediated by inhibition of cyclooxygenase (COX) activity, the principal pharmacological target of NSAIDs. Furthermore, short-term administration of ibuprofen to mice that produce mutant beta-amyloid precursor protein (APP) lowered their brain levels of Abeta42. In cultured cells, the decrease in Abeta42 secretion was accompanied by an increase in the Abeta(1-38) isoform, indicating that NSAIDs subtly alter gamma-secretase activity without significantly perturbing other APP processing pathways or Notch cleavage. Our findings suggest that NSAIDs directly affect amyloid pathology in the brain by reducing Abeta42 peptide levels independently of COX activity and that this Abeta42-lowering activity could be optimized to selectively target the pathogenic Abeta42 species.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspartic Acid Endopeptidases; Brain; CHO Cells; Cricetinae; Disease Models, Animal; Endopeptidases; Enzyme-Linked Immunosorbent Assay; Humans; Ibuprofen; Indomethacin; Mass Spectrometry; Mice; Mice, Transgenic; Peptide Fragments; Prostaglandin-Endoperoxide Synthases; Sulindac; Tumor Cells, Cultured