Neuroprotective properties of solanum leaves in transgenic Drosophila melanogaster model of Alzheimer's disease.

INTRODUCTION: We investigated the effect of African eggplant (AE) (Solanum macrocarpon L) and Black nightshade (BN) (Solanum nigrum L) leaves; two tropical vegetables consumed by humans on behavioural, biochemical and histological indices in Drosophila melanogaster model of Alzheimer's disease (AD). MATERIALS AND METHOD: Transgenic flies expressing human Amyloid Precursor Protein (hAPP) and ß-secretase (hBACE 1) were exposed to the pulverised leaf samples (0.1 and 1.0%) in their diets for fourteen days. Thereafter, the flies were assessed for their behavioural indices and routine histology of brain cells. Furthermore, fly head homogenates were assayed for ß-amyloid level, activities of acetylcholinesterase (AChE) and ß-secretase (BACE-1), as well as oxidative stress markers. RESULTS: Result showed that the significantly lower (p < 0.05) behavioural parameters (survival, locomotor performance and memory index), higher AChE and BACE-1 activities, ß-amyloid, ROS and lipid peroxidation levels, as well as reduced antioxidant indices observed in the AD flies, were significantly ameliorated (p < 0.05) in AD flies treated with the leaf samples. DISCUSSION: This study has showed that leaves of AE and BN ameliorated behavioural and biochemical indices in AD flies via neural enzyme modulatory, and antioxidant mechanisms. CONCLUSION: Hence, this study further justifies the neuroprotective properties of both AE and BN.

Long-term oral administration of hyperoside ameliorates AD-related neuropathology and improves cognitive impairment in APP/PS1 transgenic mice.

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disorder characterized by the pathological hallmarks of ß-amyloid plaque deposits, tau pathology, inflammation, and cognitive decline. Hyperoside, a flavone glycoside isolated from Rhododendron brachycarpum G. Don (Ericaceae), has neuroprotective effects against Aß both in vitro and in vivo. However, whether hyperoside could delay AD pathogenesis remains unclear. In the present study, we observed if chronic treatment with hyperoside can reverse pathological progressions of AD in the APP/PS1 transgenic mouse model. Meanwhile, we attempted to elucidate the molecular mechanisms involved in regulating its effects. After 9 months of treatment, we found that hyperoside can improve spatial learning and memory in APP/PS1 transgenic mice, reduce amyloid plaque deposition and tau phosphorylation, decrease the number of activated microglia and astrocytes, and attenuate neuroinflammation and oxidative stress in the brain of APP/PS1 mice. These beneficial effects may be mediated in part by influencing reduction of BACE1 and GSK3ß levels. Hyperoside confers neuroprotection against the pathology of AD in APP/PS1 mouse model and is emerging as a promising therapeutic candidate drug for AD.

GSI Treatment Preserves Protein Synthesis in C2C12 Myotubes.

It has been demonstrated that inhibiting Notch signaling through γ-secretase inhibitor (GSI) treatment increases myogenesis, AKT/mTOR signaling, and muscle protein synthesis (MPS) in C2C12 myotubes. The purpose of this study was to determine if GSI-mediated effects on myogenesis and MPS are dependent on AKT/mTOR signaling. C2C12 cells were assessed for indices of myotube formation, anabolic signaling, and MPS following GSI treatment in combination with rapamycin and API-1, inhibitors of mTOR and AKT, respectively. GSI treatment increased several indices of myotube fusion and MPS in C2C12 myotubes. GSI-mediated effects on myotube formation and fusion were completely negated by treatment with rapamycin and API-1. Meanwhile, GSI treatment was able to rescue MPS in C2C12 myotubes exposed to rapamycin or rapamycin combined with API-1. Examination of protein expression revealed that GSI treatment was able to rescue pGSK3ß Ser9 despite AKT inhibition by API-1. These findings demonstrate that GSI treatment is able to rescue MPS independent of AKT/mTOR signaling, possibly via GSK3ß modulation.

Investigation of anti-Alzheimer's activity of aqueous extract of areca nuts (Areca catechu L): in vitro and in vivo studies / Investigación de la actividad anti-Alzheimer del extracto acuoso de nueces de areca (Areca catechu L): estudios in vitro e in vivo

Alzheimer's disease (AD) is an age-related neurodegenerative disorder. Sever cognitive and memory impairments, huge increase in the prevalence of the disease, and lacking definite cure have absorbed worldwide efforts to develop therapeutic approaches. Since many drugs have failed in the clinical trials due to multifactorial nature of AD, symptomatic treatments are still in the center attention and now, nootropic medicinal plants have been found as versatile ameliorators to reverse memory disorders. In this work, anti-Alzheimer's activity of aqueous extract of areca nuts (Areca catechu L.) was investigated via in vitro and in vivo studies. It depicted good amyloid ß (Aß) aggregation inhibitory activity, 82% at 100 µg/mL. In addition, it inhibited beta-secretase 1 (BACE1) with IC50 value of 19.03 µg/mL. Evaluation of neuroprotectivity of the aqueous extract of the plant against H2O2-induced cell death in PC12 neurons revealed 84.5% protection at 1 µg/mL. It should be noted that according to our results obtained from Morris Water Maze (MWM) test, the extract reversed scopolamine-induced memory deficit in rats at concentrations of 1.5 and 3 mg/kg.

La enfermedad de Alzheimer (EA) es un trastorno neurodegenerativo relacionado con la edad. Los severos deterioros cognitivos y de la memoria, el enorme aumento de la prevalencia de la enfermedad y la falta de una cura definitiva han absorbido los esfuerzos mundiales para desarrollar enfoques terapéuticos. Dado que muchos fármacos han fallado en los ensayos clínicos debido a la naturaleza multifactorial de la EA, los tratamientos sintomáticos siguen siendo el centro de atención y ahora, las plantas medicinales nootrópicas se han encontrado como mejoradores versátiles para revertir los trastornos de la memoria. En este trabajo, se investigó la actividad anti-Alzheimer del extracto acuoso de nueces de areca (Areca catechu L.) mediante estudios in vitro e in vivo. Representaba una buena actividad inhibidora de la agregación de amiloide ß (Aß), 82% a 100 µg/mL. Además, inhibió la beta-secretasa 1 (BACE1) con un valor de CI50 de 19,03 µg/mL. La evaluación de la neuroprotección del extracto acuoso de la planta contra la muerte celular inducida por H2O2 en neuronas PC12 reveló una protección del 84,5% a 1 µg/mL. Cabe señalar que, de acuerdo con nuestros resultados obtenidos de la prueba Morris Water Maze (MWM), el extracto revirtió el déficit de memoria inducido por escopolamina en ratas a concentraciones de 1,5 y 3 mg/kg.

Screening Traditional Chinese Medicine Combination for Cotreatment of Alzheimer's Disease and Type 2 Diabetes Mellitus by Network Pharmacology.

BACKGROUND: In recent years, the efficacy of type 2 diabetes mellitus (T2DM) drugs in the treatment of Alzheimer's disease (AD) has attracted extensive interest owing to the close associations between the two diseases. OBJECTIVE: Here, we screened traditional Chinese medicine (TCM) and multi-target ingredients that may have potential therapeutic effects on both T2DM and AD from T2DM prescriptions. METHODS: Network pharmacology and molecular docking were used. RESULTS: Firstly, the top 10 frequently used herbs and corresponding 275 active ingredients were identified from 263 T2DM-related TCM prescriptions. Secondly, through the comparative analysis of 208 potential targets of ingredients, 1,740 T2DM-related targets, and 2,060 AD-related targets, 61 common targets were identified to be shared. Thirdly, by constructing pharmacological network, 26 key targets and 154 representative ingredients were identified. Further enrichment analysis showed that common targets were involved in regulating multiple pathways related to T2DM and AD, while network analysis also found that the combination of Danshen (Radix Salviae)-Gancao (Licorice)-Shanyao (Rhizoma Dioscoreae) contained the vast majority of the representative ingredients and might be potential for the cotreatment of the two diseases. Fourthly, MAPK1, PPARG, GSK3B, BACE1, and NR3C1 were selected as potential targets for virtual screening of multi-target ingredients. Further docking studies showed that multiple natural compounds, including salvianolic acid J, gancaonin H, gadelaidic acid, icos-5-enoic acid, and sigmoidin-B, exhibited high binding affinities with the five targets. CONCLUSION: To summarize, the present study provides a potential TCM combination that might possess the potential advantage of cotreatment of AD and T2DM.

The role of GLP-1/GIP receptor agonists in Alzheimer's disease.

BACKGROUND: New glucagon-like peptide-1 (GLP-1) analogues developed in recent years have a long half-life and offer further prospects for clinical application. At present, the neuroprotection of GLP-1 analogues in Alzheimer's disease (AD) has just begun to be explored. OBJECTIVES: To investigate how glucagon-like peptide-1 (liraglutide) plays a protective role in AD by regulating tau activation and BACE1 expression. MATERIAL AND METHODS: Human neuroblastoma cell line SH-SY5Y cells were cultured in vitro and pretreated with different concentrations of liraglutide, and then treated with different concentrations of okadaic acid (OA) in order to observe the apoptosis of the SH-SY5Y cells. After liraglutide treatment, the apoptosis of neurons in AD rats was detected using flow cytometry, and tau activation and ß-site APP cleaving enzyme 1 (BACE1) expression were detected using western blot. RESULTS: Different concentrations of OA were able to induce apoptosis of SH-SY5Y cells in a dose-dependent manner. Different concentrations of liraglutide were used to pretreat SH-SY5Y cells, which were able to protect the SH-SY5Y cells from apoptosis induced by OA. Okadaic acid significantly increased tau activation and BACE1 expression in the SH-SY5Y cells, which was blocked with liraglutide pretreatment. The results of a water maze experiment showed that liraglutide had significant protective effects on memory and cognitive ability in AD rats induced with OA, inhibited apoptosis of neural cells in AD rats, and inhibited tau activation and BACE1 expression of neural cells in AD rats induced with OA. CONCLUSIONS: Liraglutide has a protective effect on AD in vivo and in vitro, which may be mediated by preventing neuronal apoptosis and inhibiting the activation of tau and the expression of BACE1.

New BACE1 Chimeric Peptide Inhibitors Selectively Prevent AßPP-ß Cleavage Decreasing Amyloid-ß Production and Accumulation in Alzheimer's Disease Models.

BACKGROUND: A disease-modifying therapy for Alzheimer's disease (AD) is still an unmet clinical need. The formation of amyloid-ß (Aß) requires the initial cleavage of the amyloid-ß protein precursor (AßPP) by BACE1 (beta-site AßPP cleaving enzyme 1), which is a prime therapeutic target for AD. OBJECTIVE: We aimed to design and develop a selective BACE1 inhibitor suitable to AD treatment. METHODS: The new BACE1 inhibitors consist on a chimeric peptide including a sequence related to the human Swedish mutant form of AßPP (AßPPswe) conjugated with the TAT carrier that facilitates cell membrane permeation and the crossing of the blood-brain barrier. Additionally to the chimeric peptide in the L-form, we developed a D-retroinverso chimeric peptide. The latter strategy, never used with BACE1 inhibitors, is considered to favor a significantly higher half-life and lower immunogenicity. RESULTS: We found that both chimeric peptides inhibit recombinant BACE1 activity and decrease Aß40/42 production in Neuro-2a (N2A) cells expressing AßPPswe without inducing cytotoxicity. The intraperitoneal administration of these peptides to 3xTg-AD mice decreased plasma and brain Aß40/42 levels, as well as brain soluble AßPPß production. Also, a reduction of insoluble Aß was observed in the brain after chronic treatment. Noteworthy, the chimeric peptides selectively inhibited the AßPP-ß cleavage relatively to the proteolysis of other BACE1 substrates such as close homologue of L1 (CHL1) and seizure-related gene 6 (SEZ6). CONCLUSIONS: Overall these new BACE1 chimeric peptideshold promising potential as a selective disease-modifying therapy for AD.

Anti-HIV drugs promote ß-amyloid deposition and impair learning and memory in BALB/c mice.

OBJECTIVES: Growing evidence suggested that antiretroviral (ARV) drugs may promote amyloid beta (Aß) accumulation in HIV-1-infected brain and the persistence of HIV-associated neurocognitive disorders (HANDs). It has also been shown that lipid peroxidation upregulates ß-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) expression and subsequently promotes Aß peptide production. In the present study, we examined whether chronic exposure to the anti-HIV drugs tenofovir disoproxil fumarate (TDF) and nevirapine induces lipid peroxidation thereby promoting BACE1 and Aß generation and consequently impair cognitive function in mice. METHODS: TDF or nevirapine was orally administered to female BALB/c mice once a day for 8 weeks. On the 7th week of treatment, spatial learning and memory were assessed using the Morris water maze test. The levels of lipid peroxidation, BACE1, amyloid ß 1-42 (Aß1-42) and Aß deposits were measured in the hippocampal tissue upon completion of treatment. RESULTS: Chronic administration of nevirapine induced spatial learning and memory impairment in the Morris water maze test, whereas TDF did not have an effect. TDF and nevirapine administration increased hippocampal lipid peroxidation and Aß1-42 concentration. Nevirapine further upregulated BACE1 expression and Aß deposits. CONCLUSION: Our results suggest that chronic exposure to TDF and nevirapine contributes to hippocampal lipid peroxidation and Aß accumulation, respectively, as well as spatial learning and memory deficits in mice even in the absence of HIV infection. These findings further support a possible link between ARV drug toxicity, Aß accumulation and the persistence of HANDs.

Computer-Aided Drug Design of ß-Secretase, γ-Secretase and Anti-Tau Inhibitors for the Discovery of Novel Alzheimer's Therapeutics.

Aging-associated neurodegenerative diseases, which are characterized by progressive neuronal death and synapses loss in human brain, are rapidly growing affecting millions of people globally. Alzheimer's is the most common neurodegenerative disease and it can be caused by genetic and environmental risk factors. This review describes the amyloid-ß and Tau hypotheses leading to amyloid plaques and neurofibrillary tangles, respectively which are the predominant pathways for the development of anti-Alzheimer's small molecule inhibitors. The function and structure of the druggable targets of these two pathways including ß-secretase, γ-secretase, and Tau are discussed in this review article. Computer-Aided Drug Design including computational structure-based design and ligand-based design have been employed successfully to develop inhibitors for biomolecular targets involved in Alzheimer's. The application of computational molecular modeling for the discovery of small molecule inhibitors and modulators for ß-secretase and γ-secretase is summarized. Examples of computational approaches employed for the development of anti-amyloid aggregation and anti-Tau phosphorylation, proteolysis and aggregation inhibitors are also reported.

δ-secretase in neurodegenerative diseases: mechanisms, regulators and therapeutic opportunities.

Mammalian asparagine endopeptidase (AEP) is a cysteine protease that cleaves its protein substrates on the C-terminal side of asparagine residues. Converging lines of evidence indicate that AEP may be involved in the pathogenesis of several neurological diseases, including Alzheimer's disease, Parkinson's disease, and frontotemporal dementia. AEP is activated in the aging brain, cleaves amyloid precursor protein (APP) and promotes the production of amyloid-ß (Aß). We renamed AEP to δ-secretase to emphasize its role in APP fragmentation and Aß production. AEP also cleaves other substrates, such as tau, α-synuclein, SET, and TAR DNA-binding protein 43, generating neurotoxic fragments and disturbing their physiological functions. The activity of δ-secretase is tightly regulated at both the transcriptional and posttranslational levels. Here, we review the recent advances in the role of δ-secretase in neurodegenerative diseases, with a focus on its biochemical properties and the transcriptional and posttranslational regulation of its activity, and discuss the clinical implications of δ-secretase as a diagnostic biomarker and therapeutic target for neurodegenerative diseases.

Pharmacokinetic and Pharmacodynamic Effects of a γ-Secretase Modulator, PF-06648671, on CSF Amyloid-ß Peptides in Randomized Phase I Studies.

γ-Secretase modulators (GSMs) represent a promising therapy for Alzheimer's disease by reducing pathogenic amyloid-ß (Aß) peptide production. Three phase I studies (NCT02316756, NCT02407353, and NCT02440100) investigated the safety/tolerability, pharmacokinetics (PKs), and pharmacodynamics (PDs) of the oral GSM, PF-06648671. A PK/PD indirect-response model was developed (using biomarker data) to simultaneously characterize differential effects of PF-06648671 on multiple Aß species in cerebrospinal fluid (CSF). Healthy subjects (n = 120) received single doses or multiple-ascending doses of PF-06648671/placebo for 14 days. No serious adverse events occurred; severe adverse eventswere deemed not drug related. PF-06648671 decreased Aß42 and Aß40 concentrations in CSF, with greater effects on Aß42, and increased Aß37 and Aß38 levels, particularly Aß37. No significant change in total Aß was observed. The PK/PD model well described the tendency of observed CSF Aß data and the steady-state effects of PF-06648671, supporting its use for predicting central Aß effects and optimal dose selection for GSMs in future trials.

Activation of peroxisome proliferator-activated receptor delta suppresses BACE1 expression by up-regulating SOCS1 in a JAK2/STAT1-dependent manner.

Neuronal expression of beta-secretase 1 (BACE1) has been implicated in the progression of Alzheimer's disease. However, the mechanisms that regulate BACE1 expression are unclear. Here, we show that peroxisome proliferator-activated receptor delta (PPARδ) decreases BACE1 expression by up-regulating suppressor of cytokine signaling 1 (SOCS1) in SH-SY5Y neuroblastoma cells. The activation of PPARδ by GW501516, a specific PPARδ agonist, inhibited expression of BACE1. This effect was abrogated by shRNA-mediated knockdown of PPARδ and by treatment with the PPARδ antagonist GSK0660, indicating that PPARδ is involved in GW501516-mediated suppression of BACE1 expression. On the other hand, GW501516-activated PPARδ induced expression of SOCS1, which is a negative regulator of cytokine signal transduction, at the transcriptional level by binding to a PPAR response element in its promoter. This GW501516-mediated induction of SOCS1 expression led to down-regulation of BACE1 expression via inactivation of signal transducer and activator of transcription 1. GW501516-activated PPARδ suppressed the generation of neurotoxic amyloid beta (Aß) in accordance with the decrease in BACE1 expression. Taken together, these results indicate that PPARδ attenuates BACE1 expression via SOCS1-mediated inhibition of signal transducer and activator of transcription 1 signaling, thereby suppressing BACE1-associated generation of neurotoxic Aß.

Structure-Based Design of Selective ß-Site Amyloid Precursor Protein Cleaving Enzyme 1 (BACE1) Inhibitors: Targeting the Flap to Gain Selectivity over BACE2.

BACE1 inhibitors hold potential as agents in disease-modifying treatment for Alzheimer's disease. BACE2 cleaves the melanocyte protein PMEL in pigment cells of the skin and eye, generating melanin pigments. This role of BACE2 implies that nonselective and chronic inhibition of BACE1 may cause side effects derived from BACE2. Herein, we describe the discovery of potent and selective BACE1 inhibitors using structure-based drug design. We targeted the flap region, where the shape and flexibility differ between these enzymes. Analysis of the cocrystal structures of an initial lead 8 prompted us to incorporate spirocycles followed by its fine-tuning, culminating in highly selective compounds 21 and 22. The structures of 22 bound to BACE1 and BACE2 revealed that a relatively high energetic penalty in the flap of the 22-bound BACE2 structure may cause a loss in BACE2 potency, thereby leading to its high selectivity. These findings and insights should contribute to responding to the challenges in exploring selective BACE1 inhibitors.

Multidisciplinary approaches for targeting the secretase protein family as a therapeutic route for Alzheimer's disease.

The continual increase of the aging population worldwide renders Alzheimer's disease (AD) a global prime concern. Several attempts have been focused on understanding the intricate complexity of the disease's development along with the on- andgoing search for novel therapeutic strategies. Incapability of existing AD drugs to effectively modulate the pathogenesis or to delay the progression of the disease leads to a shift in the paradigm of AD drug discovery. Efforts aimed at identifying AD drugs have mostly focused on the development of disease-modifying agents in which effects are believed to be long lasting. Of particular note, the secretase enzymes, a group of proteases responsible for the metabolism of the ß-amyloid precursor protein (ßAPP) and ß-amyloid (Aß) peptides production, have been underlined for their promising therapeutic potential. This review article attempts to comprehensively cover aspects related to the identification and use of drugs targeting the secretase enzymes. Particularly, the roles of secretases in the pathogenesis of AD and their therapeutic modulation are provided herein. Moreover, an overview of the drug development process and the contribution of computational (in silico) approaches for facilitating successful drug discovery are also highlighted along with examples of relevant computational works. Promising chemical scaffolds, inhibitors, and modulators against each class of secretases are also summarized herein. Additionally, multitarget secretase modulators are also taken into consideration in light of the current growing interest in the polypharmacology of complex diseases. Finally, challenging issues and future outlook relevant to the discovery of drugs targeting secretases are also discussed.

Ganglioside Hp-s1 Analogue Inhibits Amyloidogenic Toxicity in Alzheimer's Disease Model Cells.

Alzheimer's disease (AD) is characterized by extracellular deposition of amyloid plaques, which are predominantly composed of amyloid-ß (Aß) peptide derived from amyloid precursor protein (APP) cleavage. APP interacts with tropomyosin receptor kinase A, a neurotrophic receptor associated with gangliosides and mediating neuronal survival and differentiation through the extracellular signal-regulated protein kinase (ERK) pathway. The ganglioside Hp-s1's analogue Hp-s1A exerts neuritogenic activity; however, its effect on AD pathology remains unknown. To test the hypothesis that Hp-s1A is a potential candidate to treat AD, we established the AD-modeled cell line by expressing human Swedish and Indiana APP gene (APP-Swe/Ind) in N2a mouse neuroblastoma cells. The cells were treated with Hp-s1A or monosialoganglioside GM1 for comparison. The AD model cells expressing APP-Swe/Ind exhibited a significant reduction in viability, as well as neurite outgrowth rate, in comparison to the control cells expressing APP-695. APP C-terminal fragment-ß (CTFß) and Aß42 were increased in the AD cell lysates and the culture media, respectively. With the treatment of either Hp-s1A or GM1 at 1 µM, the AD model cells showed a significant increase in viability; however, only Hp-s1A reduced CTFß levels in these cells. Further analysis of the culture media revealed that Hp-s1A also reduced Aß42 production from AD model cells. The phosphorylation of ERK was elevated and the neurite outgrowth rate was restored with Hp-s1A treatment. In conclusion, the ganglioside analogue Hp-s1A inhibited amyloidogenic processing of APP and promoted neurotrophic activity and survival of AD model cells. Hp-s1A has great potential in AD therapeutic development.

Contrasting effects of acute and long-term corticosterone treatment on amyloid-ß, beta-secretase 1 expression, and nuclear factor kappa B nuclear translocation.

Regulation of neuroinflammation is critical to control the detrimental impact of chronic stress in the central nervous system. Neuroinflammation occurs in response to chronic stress, leading to enhanced neuronal damage in the brain. We investigated the regulatory effects of stress hormone corticosterone on neuroinflammation regulator, as well as amyloid-ß and Beta-secretase 1 related signaling. We demonstrate that corticosterone can both positively and negatively regulate amyloid-ß expression, which may be related to the ratio of neuroinflammation regulator and Beta-secretase 1 signaling in rat primary cortical neurons. Thirty minutes of treatment with 1 µM corticosterone significantly decreased the nuclear translocation of neuroinflammation mediator neuroinflammation regulator (Western Blot: P < 0.05, Immunofluorescence: P < 0.001) and production of Beta-secretase 1 enzyme (P < 0.01), which was accompanied by a reduction in amyloid-ß1-42 levels (P < 0.01). In contrast, 1 µM corticosterone treatment over 3 days increased nuclear neuroinflammation regulator localization (P < 0.001), followed by the upregulation of Beta-secretase 1 (P < 0.01) and amyloid-ß1-42 (P < 0.05) expression. This work is the first to demonstrate that the duration of corticosterone exposure can promote or inhibit amyloid-ß production, and to link this effect with Beta-secretase 1 / neuroinflammation regulator signaling, together with providing valuable insight into the mechanisms of neuroinflammation and neuroprotection.

Lipid bilayer position and orientation of novel carprofens, modulators of γ-secretase in Alzheimer's disease.

γ-Secretase is an integral membrane protein complex and is involved in the cleavage of the amyloid precursor protein APP to produce amyloid-ß peptides. Amyloid-ß peptides are considered causative agents for Alzheimer's disease and drugs targeted at γ-secretase are investigated as therapeutic treatments. We synthesized new carprofen derivatives, which showed γ-secretase modulating activity and determined their precise position, orientation, and dynamics in lipid membranes by combining neutron diffraction, solid-state NMR spectroscopy, and molecular dynamics simulations. Our data indicate that the carprofen derivatives are inserted into the membrane interface, where the exact position and orientation depends on the lipid phase. This knowledge will help to understand the docking of carprofen derivatives to γ-secretase and in the design of new potent drugs. The approach presented here promises to serve as a general guideline how drug/target interactions in membranes can be analyzed in a comprehensive manner.

Lead exposure induces Alzheimers's disease (AD)-like pathology and disturbes cholesterol metabolism in the young rat brain.

Lead exposure has been evidenced as a risk factor for Alzheimer's disease (AD), mainly affecting the ageing. However, the early manifestation and mechanisms of AD-like pathology induced by lead exposure remains to be elucidated. Considering the fact that impaired cholesterol metabolism is associated with many neurodegenerative disorders including AD, in this study we focused on the role of cholesterol metabolism in lead induced premature AD-like pathology. We treated weaning rats with lead at different concentrations for 4 weeks. We found that developmental lead exposure increased amyloid-beta (Aß) accumulation and amyloid plaque deposition in the cortex and hippocampus. Lead exposure increased amyloid precursor protein (APP) expression and activated the sterol regulatory element binding protein 2 (SREBP2)-beta secretase (BACE1) pathway. In addition, we found that lead exposure decreased cholesterol levels by upregulating the expression of liver X receptor-a (LXR-a) and ATP-binding cassette transporter protein family member A1 (ABCA1) and decreasing the expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CR) and low density lipoprotein receptor (LDL-R) in young rat brain tissues. Taken together, our data demonstrated that developmental lead exposure induced early manifestation of AD-like pathology and disturbed cholesterol metabolism in young rat brains.

Compound CID 9998128 Is a Potential Multitarget Drug for Alzheimer's Disease.

We have probed small molecule compound CID 9998128 as a potential multitarget drug for the Alzheimer's disease (AD) using in silico and in vitro experiments. By all-atom simulation and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method, we have demonstrated that this compound strongly binds to both amyloid ß42 (Aß42) fibrils and ß-secretase, and the van der Waals interaction dominates over the electrostatic interaction in binding affinity. A detailed analysis at the atomic level revealed that indazole in CID 99998128 structure made a major contribution to instability of all studied complexes. In vitro experiments have shown that CID 9998128 inhibits the Aß42 amyloid fibrillization and is capable to clear Aß42 fibrils. Moreover, the compound dose-dependently decreases ß-site amyloid precursor protein cleaving enzyme (BACE-1) activity with EC50 value in micromolar range. Thus, our study has revealed that CID 9998128 is a good candidate for AD treatment through preventing production of Aß peptides and degrading their aggregates. For drug design, we predict that the chemical structure of potent AD multitarget inhibitors should not contain indazole.

In Silico Identification and Experimental Validation of Novel Anti-Alzheimer's Multitargeted Ligands from a Marine Source Featuring a "2-Aminoimidazole plus Aromatic Group" Scaffold.

Multitargeting or polypharmacological approaches, looking for single chemical entities retaining the ability to bind two or more molecular targets, are a potentially powerful strategy to fight complex, multifactorial pathologies. Unfortunately, the search for multiligand agents is challenging because only a small subset of molecules contained in molecular databases are bioactive and even fewer are active on a preselected set of multiple targets. However, collections of natural compounds feature a significantly higher fraction of bioactive molecules than synthetic ones. In this view, we searched our library of 1175 natural compounds from marine sources for molecules including a 2-aminoimidazole+aromatic group motif, found in known compounds active on single relevant targets for Alzheimer's disease (AD). This identified two molecules, a pseudozoanthoxanthin (1) and a bromo-pyrrole alkaloid (2), which were predicted by a computational approach to possess interesting multitarget profiles on AD target proteins. Biochemical assays experimentally confirmed their biological activities. The two compounds inhibit acetylcholinesterase, butyrylcholinesterase, and ß-secretase enzymes in high- to sub-micromolar range. They are also able to prevent and revert ß-amyloid (Aß) aggregation of both Aß1-40 and Aß1-42 peptides, with 1 being more active than 2. Preliminary in vivo studies suggest that compound 1 is able to restore cholinergic cortico-hippocampal functional connectivity.