AID	Name	Type	Comment
1460	qHTS for Inhibitors of Tau Fibril Formation, Thioflavin T Binding	confirmatory
1468	qHTS for Inhibitors of Tau Fibril Formation, Fluorescence Polarization	confirmatory
1475	Quantitative High-Throughput Screen for Inhibitors of Tau Fibril Formation: Summary	summary

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.

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.

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.

Grant Number: X01 MH083262-01