Bookmark and Share
BioAssay: AID 2101

qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease

Glucocerebrosidase (GC) catalyzes the hydrolysis of beta-glucocerebroside to glucose and ceramide in lysosomes. Mutations in the glucocerebrosidase gene result in Gaucher disease, an autosomal recessive lysosomal storage disorder. Many of the mutations encountered in patients with Gaucher disease are missense alterations that may cause misfolding, decreased stability and/or mistrafficking of this more ..
_
   
 Tested Compounds
 Tested Compounds
All(321562)
 
 
Active(295)
 
 
Inactive(310035)
 
 
Inconclusive(11499)
 
 
 Tested Substances
 Tested Substances
All(326770)
 
 
Active(299)
 
 
Inactive(314877)
 
 
Inconclusive(11594)
 
 
AID: 2101
Data Source: NCGC (GCNS623)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2009-11-05
Modify Date: 2010-11-02

Data Table ( Complete ):           Active    All
Target
BioActive Compounds: 295
Depositor Specified Assays
Show more
AIDNameTypeProbeComment
1473Quantitative High-Throughput Screen for Inhibitors and Activators of Human alpha-Glucosidase as a Potential Chaperone Treatment of Pompe Disease: Summarysummary1
2293Direct Measure of the Activation of Acid alpha-Glucosidase Catalytic Rateother
2577qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Alpha-Glucosidase Counterscreenconfirmatory
2578qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Alpha-Galactosidase Counterscreenconfirmatory
2587qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Chaperone Activity in Gauche Fibroblasts After Multi-day Incubation with Compoundconfirmatory
2588qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Activity in Non-Mutant Spleen Homogenate Using a Red Fluorescent Substrateconfirmatory
2589qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Chaperone Activity in Non-Gauche Fibroblasts After Multi-day Incubation with Compoundconfirmatory
2590qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Primary Screen Confirmationconfirmatory
2592qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Activity in Non-Mutant Spleen Homogenateconfirmatory
2593qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Summarysummary2
2595qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Purified Non-mutant Glucocerebrosidaseconfirmatory
2596qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Purified N370S Glucocerebrosidase Cleavage of Glucosylceramideconfirmatory
2597qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Purified N370S Glucocerebrosidaseconfirmatory
2613qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Activity in N370S Spleen Homogenate Using a Red Fluorescent Substrateconfirmatory
2671qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Hit Validationconfirmatory
488845qHTS Assay for Inhibitors and Activators of N370S glucocerebrosidase as a Potential Chaperone Treatment of Gaucher Disease: Primary Screen Confirmation Using LC/MSconfirmatory
Description:
NIH Chemical Genomics Center [NCGC]
NIH Molecular Libraries Probe Production Centers Network [MLPCN]

MLPCN Grant: MH086442-01
Assay Submitter (PI): Wei Zheng

Glucocerebrosidase (GC) catalyzes the hydrolysis of beta-glucocerebroside to glucose and ceramide in lysosomes. Mutations in the glucocerebrosidase gene result in Gaucher disease, an autosomal recessive lysosomal storage disorder. Many of the mutations encountered in patients with Gaucher disease are missense alterations that may cause misfolding, decreased stability and/or mistrafficking of this lysosomal protein. Some GC inhibitors have been shown to act as chemical chaperones, stabilizing the conformation of mutant proteins and thus restoring their function. These inhibitors include iminosugar analogs and three non-iminosugar inhibitors identified from a previous HTS of 62,000 compounds with the wild type recombinant enzyme. However, the enhancement of enzyme activity by the chaperone action of an enzyme inhibitor must be balanced against the direct inhibition of the enzyme. An enzyme activator could also function as a chaperone by binding to the enzyme and helping to correct its misfolding and mistrafficking. While activators for GC have not yet been identified, they may have better therapeutic potential than inhibitors. Therefore the discovery and development of chemical activators may provide a new strategy for the chaperone therapy.

We have optimized a new assay using N370S mutant GC derived from the spleen of a Gaucher patient. The new assay differs significantly from the previous screen because the N370S mutant enzyme is used instead of wildtype GC and an enzyme preparation derived from patient tissue instead of the purified recombinant GC that should have the physiologically relevant subunit/subunits and cofactors. In addition, the MLPCN compound library has expanded, which increases the chance of finding new and better probes.
Protocol
NCGC Assay Protocol Summary:

This is a fluorogenic enzyme assay with 4-methylumbelliferyl-beta-D-glucopyranoside as the substrate and N370S glucocerebrosidase from human spleen homogenate as the enzyme preparation. Upon the hydrolysis of this fluorogenic substrate, the resulting product, 4-methyllumbelliferone, can be excited at 365 nm and emits at 440 nm which can be detected by a standard fluorescence plate reader. Data were normalized to the controls for basal activity (without enzyme) and 100% activity (with enzyme). The AC50 values were determined from concentration-response data modeled with the standard Hill equation.

Assay buffer: 50 mM citric acid (titrated with potassium phosphate to pH 5.0), 100 mM potassium chloride, 10 mM sodium chloride, 1 mM magnesium chloride, 0.01% Tween-20.


1536-well assay protocol:
(1) Add 2 ul/well of spleen homogenate (27 ug final)
(2) Add 23 nL compounds in DMSO solution. The final titration was 0.5 nM to 58 uM.
(3) Add 2 ul of substrate (1 mM final)
(4) Incubate at 37C for 40 min.
(5) Add 2 ul stop solution (1M NaOH and 1M Glycine mixture, pH 10)
(6) Detect the assay plate in a ViewLux plate reader (PerkinElmer) with Ex=365 nm and Em=440nm.

Keywords: Glucocerebrosidase, beta-glucosidase, Gaucher Disease, pharmacological chaperone, chaperone therapy, high throughput screening, glucocerebrosidase inhibitor, MLSMR, MLSCN, NIH Roadmap, qHTS and NCGC
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
Show more
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 0.00164 uM (0.00164368μM**)% Activity at given concentration.Float%
15Activity at 0.00368 uM (0.00367816μM**)% Activity at given concentration.Float%
16Activity at 0.00822 uM (0.00821839μM**)% Activity at given concentration.Float%
17Activity at 0.018 uM (0.0183915μM**)% Activity at given concentration.Float%
18Activity at 0.040 uM (0.0402362μM**)% Activity at given concentration.Float%
19Activity at 0.093 uM (0.0929832μM**)% Activity at given concentration.Float%
20Activity at 0.133 uM (0.133162μM**)% Activity at given concentration.Float%
21Activity at 0.202 uM (0.20158μM**)% Activity at given concentration.Float%
22Activity at 0.417 uM (0.417308μM**)% Activity at given concentration.Float%
23Activity at 0.504 uM (0.504169μM**)% Activity at given concentration.Float%
24Activity at 0.837 uM (0.837465μM**)% Activity at given concentration.Float%
25Activity at 1.286 uM (1.28634μM**)% Activity at given concentration.Float%
26Activity at 2.348 uM (2.34763μM**)% Activity at given concentration.Float%
27Activity at 3.436 uM (3.43578μM**)% Activity at given concentration.Float%
28Activity at 5.162 uM (5.1624μM**)% Activity at given concentration.Float%
29Activity at 10.68 uM (10.6773μM**)% Activity at given concentration.Float%
30Activity at 12.83 uM (12.8347μM**)% Activity at given concentration.Float%
31Activity at 21.58 uM (21.5823μM**)% Activity at given concentration.Float%
32Activity at 32.14 uM (32.1375μM**)% Activity at given concentration.Float%
33Activity at 59.40 uM (59.4005μM**)% Activity at given concentration.Float%
34Activity at 89.08 uM (89.0793μM**)% Activity at given concentration.Float%
35Activity at 135.5 uM (135.538μM**)% Activity at given concentration.Float%
36Activity at 187.4 uM (187.356μM**)% Activity at given concentration.Float%
37Compound QCNCGC designation for data stage: 'qHTS', 'qHTS Verification', 'Secondary Profiling'String

* Activity Concentration. ** Test Concentration.
Additional Information
Grant Number: MH086442-01

Data Table (Concise)
Classification
PageFrom: