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BioAssay: AID 1712

Assay for Inhibitors of the fibrillization of the Beta-Amyloid Protein Fragment, A-beta 1-42

The microtubule-associated protein tau is an abundant protein in the axons of neurons that stabilizes microtubules. With its ability to modulate microtubule dynamics, tau contributes directly or indirectly, to key structural and regulatory cellular functions. Particularly important is the influence tau exerts on axonal transport, which allows signaling molecules, trophic factors and other more ..
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 Tested Compounds
 Tested Compounds
All(25)
 
 
Inactive(13)
 
 
Inconclusive(12)
 
 
 Tested Substances
 Tested Substances
All(26)
 
 
Inactive(13)
 
 
Inconclusive(13)
 
 
AID: 1712
Data Source: NCGC (TAU2490)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2009-05-04

Data Table ( Complete ):           All
Target
Sequence: beta-amyloid peptide, A beta {N-terminal} [human, cerebrospinal fluid, conditioned medium of mixed-brain cell cultures, Peptide Partial, 33 aa]
Description ..   
Protein Family: Beta-amyloid peptide (beta-APP)

Related Protein 3D Structures     More BioActivity Data..
Tested Compounds:
Depositor Specified Assays
AIDNameTypeComment
1460qHTS for Inhibitors of Tau Fibril Formation, Thioflavin T Bindingconfirmatory
1468qHTS for Inhibitors of Tau Fibril Formation, Fluorescence Polarizationconfirmatory
1475Quantitative High-Throughput Screen for Inhibitors of Tau Fibril Formation: Summarysummary
Description:
NIH Molecular Libraries Probe Production Network [MLPCN]
NIH Chemical Genomics Center [NCGC]

MLPCN Grant: X01 MH083262-01
Assay Provider: Carlo Ballatore, University of Pennsylvania


NCGC Assay Overview:
The microtubule-associated protein tau is an abundant protein in the axons of neurons that stabilizes microtubules. With its ability to modulate microtubule dynamics, tau contributes directly or indirectly, to key structural and regulatory cellular functions. Particularly important is the influence tau exerts on axonal transport, which allows signaling molecules, trophic factors and other essential cellular constituents to travel along the axons. Under pathological conditions, tau becomes sequestered into insoluble aggregates called neurofibrillary tangles. This phenomenon is believed to have pathological consequences by promoting axonal transport deficits that ultimately lead to synaptic dysfunction and neuronal loss. Beta-amyloid protein undergoes a similar type of aggregation as tau and is implicated in the pathology of Alzheimer's disease. To examine the selectivity of tau fibrillization inhibitors, compounds were tested in an in vitro assay for fibrillization of the beta-amyloid fragment, A-beta 1-42.

Crystal, A. S., Giasson, B. I., Crowe, A., Kung, M. P., Zhuang, Z. P., Trojanowski, J. Q., and Lee, V. M. Y. (2003) Journal of Neurochemistry 86, 1359-1368.
Protocol
NCGC Assay Protocol Summary:
Synthetic A-beta 1-42 aliquots were reconstituted to 2 mg/ml in DMSO and then diluted to 15 uM in 25 mM Tris, pH 7.0 buffer to which test compound was added at 50 uM final concentration, or at several concentrations ranging from 0.16-40 uM. The reaction mixtures were dispensed at 25 ul/well into a 384-well plate and then incubated at 37 C for 4 hrs. Upon completion of the reaction, 25 ul of 25 uM ThT was added to each well followed by ThT fluorescence readings as described above for K18PL.
Comment
Compound Ranking:

1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.
Result Definitions
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TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1PhenotypeIndicates type of activity observed: inhibitor, activator, fluorescent, cytotoxic, inactive, or inconclusive.String
2Potency*Concentration at which compound exhibits half-maximal efficacy, AC50. Extrapolated AC50s also include the highest efficacy observed and the concentration of compound at which it was observed.FloatμM
3EfficacyMaximal efficacy of compound, reported as a percentage of control. These values are estimated based on fits of the Hill equation to the dose-response curves.Float%
4Analysis CommentAnnotation/notes on a particular compound's data or its analysis.String
5Curve_DescriptionA description of dose-response curve quality. A complete curve has two observed asymptotes; a partial curve may not have attained its second asymptote at the highest concentration tested. High efficacy curves exhibit efficacy greater than 80% of control. Partial efficacies are statistically significant, but below 80% of control.String
6Fit_LogAC50The logarithm of the AC50 from a fit of the data to the Hill equation (calculated based on Molar Units).Float
7Fit_HillSlopeThe Hill slope from a fit of the data to the Hill equation.Float
8Fit_R2R^2 fit value of the curve. Closer to 1.0 equates to better Hill equation fit.Float
9Fit_InfiniteActivityThe asymptotic efficacy from a fit of the data to the Hill equation.Float%
10Fit_ZeroActivityEfficacy at zero concentration of compound from a fit of the data to the Hill equation.Float%
11Fit_CurveClassNumerical encoding of curve description for the fitted Hill equation.Float
12Excluded_PointsWhich dose-response titration points were excluded from analysis based on outlier analysis. Each number represents whether a titration point was (1) or was not (0) excluded, for the titration series going from smallest to highest compound concentrations.String
13Max_ResponseMaximum activity observed for compound (usually at highest concentration tested).Float%
14Activity at 0.156 uM (0.156μM**)% Activity at given concentration.Float%
15Activity at 0.313 uM (0.3128μM**)% Activity at given concentration.Float%
16Activity at 0.625 uM (0.6248μM**)% Activity at given concentration.Float%
17Activity at 1.248 uM (1.248μM**)% Activity at given concentration.Float%
18Activity at 2.504 uM (2.504μM**)% Activity at given concentration.Float%
19Activity at 5.000 uM (5μM**)% Activity at given concentration.Float%
20Activity at 10.000 uM (10μM**)% Activity at given concentration.Float%
21Activity at 20.00 uM (20μM**)% Activity at given concentration.Float%
22Activity at 40.00 uM (40μM**)% Activity at given concentration.Float%
23Activity at 80.00 uM (80μM**)% Activity at given concentration.Float%
24Compound QCNCGC designation for data stage: 'qHTS', 'qHTS Verification', 'Secondary Profiling'String

* Activity Concentration. ** Test Concentration.
Additional Information
Grant Number: X01 MH083262-01

Data Table (Concise)
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