Counterscreen for IDE inhibitors: Luminescence-based cell-based high throughput assay to identify cytotoxic compounds using HEK cells
Name: Counterscreen for IDE inhibitors: Luminescence-based cell-based high throughput assay to identify cytotoxic compounds using HEK cells. ..more
BioActive Compounds: 334
Source (MLPCN Center Name): The Scripps Research Institute Molecular Screening Center (SRIMSC)
Affiliation: The Scripps Research Institute, TSRI
Assay Provider: Malcolm Leissring, Mayo Clinic College of Medicine
Network: Molecular Library Probe Production Centers Network (MLPCN)
Grant Proposal Number: 1 R03 DA024888-01
Grant Proposal PI: Malcolm Leissring
External Assay ID: HEK293CYTOX_INH_LUMI_1536_3X%INH CSRUN
Name: Counterscreen for IDE inhibitors: Luminescence-based cell-based high throughput assay to identify cytotoxic compounds using HEK cells.
Alzheimer's disease (AD) is characterized by accumulation of amyloid beta-protein (A-beta; Abeta) in brain regions involved in memory and cognition (1). The steady-state levels of AB reflect a balance between its production via beta- and gamma-secretases and its catabolism by proteolytic degradation (2-4). Because Abeta cleavage products are less neurotoxic than intact Abeta, enzymes that cleave Abeta are of therapeutic interest for AD. In fact, upregulation of Abeta-degrading proteases can prevent AD-like pathology in beta-amyloid precursor protein (APP) transgenic mice (5), suggesting that enhancing AB degradation may be therapeutic in human AD. Insulin-degrading enzyme (IDE) is an Abeta-degrading zinc metalloprotease that requires a free thiol and bivalent cations to degrade extracellular Abeta in neurons and other cell types (6-8). The deduced sequence of IDE shares little homology to other proteinases, including cysteine, metallo-, serine, or aspartic proteases (9). Most IDE is localized inside the cell (10), where it can degrade internalized insulin (11), insulin-like growth factors I and II (12), and amylin (13), which make IDE an attractive target for type-2 diabetes. However, since IDE has also been found in the extracellular space and at the plasma membrane (6), it can function as a principal protease in Abeta catabolism (5, 14, 15). IDE secretion is not dependent upon the classical secretion pathway (16). Studies showing reduced IDE levels in human AD patients (17, 18), combined with increased brain AB levels in IDE-deficient mice (14, 15), and association studies suggesting that IDE variants may be associated with AD severity (19-23), suggest that the identification of compounds that selectively modulate IDE activity will present as important tools for the study of IDE function, AD, and diabetes (24).
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2. Selkoe, DJ, Clearing the brain's amyloid cobwebs. Neuron, 2001. 32(2): p. 177-80.
3. Eckman, EA and Eckman, CB, Abeta-degrading enzymes: modulators of Alzheimer's disease pathogenesis and targets for therapeutic intervention. Biochem Soc Trans, 2005. 33(Pt 5): p. 1101-5.
4. Hersh, LB, The insulysin (insulin degrading enzyme) enigma. Cell Mol Life Sci, 2006. 63(21): p. 2432-4.
5. Leissring, MA, Farris, W, Chang, AY, Walsh, DM, Wu, X, Sun, X, Frosch, MP and Selkoe, DJ, Enhanced proteolysis of beta-amyloid in APP transgenic mice prevents plaque formation, secondary pathology, and premature death. Neuron, 2003. 40(6): p. 1087-93.
6. Qiu, WQ, Walsh, DM, Ye, Z, Vekrellis, K, Zhang, J, Podlisny, MB, Rosner, MR, Safavi, A, Hersh, LB and Selkoe, DJ, Insulin-degrading enzyme regulates extracellular levels of amyloid beta-protein by degradation. J Biol Chem, 1998. 273(49): p. 32730-8.
7. Qiu, WQ, Ye, Z, Kholodenko, D, Seubert, P and Selkoe, DJ, Degradation of amyloid beta-protein by a metalloprotease secreted by microglia and other neural and non-neural cells. J Biol Chem, 1997. 272(10): p. 6641-6.
8. Kurochkin, IV and Goto, S, Alzheimer's beta-amyloid peptide specifically interacts with and is degraded by insulin degrading enzyme. FEBS Lett, 1994. 345(1): p. 33-7.
9. Affholter, JA, Fried, VA and Roth, RA, Human insulin-degrading enzyme shares structural and functional homologies with E. coli protease III. Science, 1988. 242(4884): p. 1415-8.
10. Qiu, WQ and Folstein, MF, Insulin, insulin-degrading enzyme and amyloid-beta peptide in Alzheimer's disease: review and hypothesis. Neurobiol Aging, 2006. 27(2): p. 190-8.
11. Fawcett, J and Rabkin, R, Degradation of insulin by isolated rat renal cortical endosomes. Endocrinology, 1993. 133(4): p. 1539-47.
12. Misbin, RI and Almira, EC, Degradation of insulin and insulin-like growth factors by enzyme purified from human erythrocytes. Comparison of degradation products observed with A14- and B26-[125I]monoiodoinsulin. Diabetes, 1989. 38(2): p. 152-8.
13. Bennett, RG, Duckworth, WC and Hamel, FG, Degradation of amylin by insulin-degrading enzyme. J Biol Chem, 2000. 275(47): p. 36621-5.
14. Farris, W, Mansourian, S, Chang, Y, Lindsley, L, Eckman, EA, Frosch, MP, Eckman, CB, Tanzi, RE, Selkoe, DJ and Guenette, S, Insulin-degrading enzyme regulates the levels of insulin, amyloid beta-protein, and the beta-amyloid precursor protein intracellular domain in vivo. Proc Natl Acad Sci U S A, 2003. 100(7): p. 4162-7.
15. Miller, BC, Eckman, EA, Sambamurti, K, Dobbs, N, Chow, KM, Eckman, CB, Hersh, LB and Thiele, DL, Amyloid-beta peptide levels in brain are inversely correlated with insulysin activity levels in vivo. Proc Natl Acad Sci U S A, 2003. 100(10): p. 6221-6.
16. Zhao, J, Li, L and Leissring, MA, Insulin-degrading enzyme is exported via an unconventional protein secretion pathway. Mol Neurodegener, 2009. 4: p. 4.
17. Perez, A, Morelli, L, Cresto, JC and Castano, EM, Degradation of soluble amyloid beta-peptides 1-40, 1-42, and the Dutch variant 1-40Q by insulin degrading enzyme from Alzheimer disease and control brains. Neurochem Res, 2000. 25(2): p. 247-55.
18. Zhao, Z, Xiang, Z, Haroutunian, V, Buxbaum, JD, Stetka, B and Pasinetti, GM, Insulin degrading enzyme activity selectively decreases in the hippocampal formation of cases at high risk to develop Alzheimer's disease. Neurobiol Aging, 2007. 28(6): p. 824-30.
19. Abraham, R, Myers, A, Wavrant-DeVrieze, F, Hamshere, ML, Thomas, HV, Marshall, H, Compton, D, Spurlock, G, Turic, D, Hoogendoorn, B, Kwon, JM, Petersen, RC, Tangalos, E, Norton, J, Morris, JC, Bullock, R, Liolitsa, D, Lovestone, S, Hardy, J, Goate, A, O'Donovan, M, Williams, J, Owen, MJ and Jones, L, Substantial linkage disequilibrium across the insulin-degrading enzyme locus but no association with late-onset Alzheimer's disease. Hum Genet, 2001. 109(6): p. 646-52.
20. Prince, JA, Feuk, L, Gu, HF, Johansson, B, Gatz, M, Blennow, K and Brookes, AJ, Genetic variation in a haplotype block spanning IDE influences Alzheimer disease. Hum Mutat, 2003. 22(5): p. 363-71.
21. Ertekin-Taner, N, Allen, M, Fadale, D, Scanlin, L, Younkin, L, Petersen, RC, Graff-Radford, N and Younkin, SG, Genetic variants in a haplotype block spanning IDE are significantly associated with plasma Abeta42 levels and risk for Alzheimer disease. Hum Mutat, 2004. 23(4): p. 334-42.
22. Bian, L, Yang, JD, Guo, TW, Sun, Y, Duan, SW, Chen, WY, Pan, YX, Feng, GY and He, L, Insulin-degrading enzyme and Alzheimer disease: a genetic association study in the Han Chinese. Neurology, 2004. 63(2): p. 241-5.
23. Vepsalainen, S, Parkinson, M, Helisalmi, S, Mannermaa, A, Soininen, H, Tanzi, RE, Bertram, L and Hiltunen, M, Insulin-degrading enzyme is genetically associated with Alzheimer's disease in the Finnish population. J Med Genet, 2007. 44(9): p. 606-8.
24. Leissring, MA, Lu, A, Condron, MM, Teplow, DB, Stein, RL, Farris, W and Selkoe, DJ, Kinetics of amyloid beta-protein degradation determined by novel fluorescence- and fluorescence polarization-based assays. J Biol Chem, 2003. 278(39): p. 37314-20.
Insulin degrading enzyme, IDE, insulysin, insulinase, beta amyloid, AB, A-beta, beta, inhibitors, inhibition, antagonists, inhibit, inhibitor, counterscreen, Alzheimer's disease, AD, diabetes, HEK cells, cytotoxicity, cytox, viability, triplicate, HTS, high throughput screen, 1536, Scripps, Scripps Florida, The Scripps Research Institute Molecular Screening Center, SRIMSC, Molecular Libraries Probe Production Centers Network, MLPCN, viability, cytotoxicity
The purpose of this assay is to determine whether compounds identified as active in a set of previous experiments entitled, "Fluorescence polarization-based cell-based high throughput primary assay to identify inhibitors of insulin-degrading enzyme (IDE)" (AID 434962) were nonselective due to HEK cytotoxicity. In this assay, HEK cells are incubated with test compounds, followed by determination of cell viability. The assay utilizes the CellTiter-Glo luminescent reagent to measure intracellular ATP in viable cells. Luciferase present in the reagent catalyzes the oxidation of beetle luciferin to oxyluciferin and light in the presence of cellular ATP. Well luminescence is directly proportional to ATP levels and cell viability. As designed, compounds that reduce cell viability will reduce ATP levels, luciferin oxidation and light production, resulting in decreased well luminescence. Compounds are tested in triplicate at a nominal concentration of 5.59 uM.
HEK cells were cultured in T-175 sq cm flasks at 37 C and 95% relative humidity (RH). The growth media consisted of Dulbecco's Modified Eagle's Media (DMEM) containing 10% v/v fetal bovine serum, 1X antibiotic mix (penicillin, streptomycin, and neomycin).
Prior to the start of the assay 500 cells in a 5 uL volume of growth media were dispensed into each well of 1536-well tissue culture-treated microtiter plates. The assay was started immediately by dispensing 28 nL of test compound in DMSO (0.06% final DMSO concentration), DMSO alone, or doxorubicin (150 uM final concentration) to the appropriate wells. Next, the plates were incubated for 48 hours at 37 C (5% CO2, 95% RH). After equilibrating the plates to room temperature for 30 minutes, the assay was stopped by dispensing 5 uL of CellTiter-Glo reagent to each well, followed by incubation at room temperature for 15 minutes. Well luminescence was measured on the ViewLux plate reader.
The percent inhibition for each compound was calculated as follows:
% Inhibition = ( 1 - ( ( Test_Compound - Median_High_Control ) / ( Median_Low_Control - Median_High_Control ) ) ) * 100
Test_Compound is defined as wells containing test compound.
Low_Control is defined as wells containing DMSO.
High_Control is defined as wells containing doxorubicin.
A mathematical algorithm was used to determine nominally cytotoxic compounds in this assay. Two values were calculated: (1) the average percent inhibition of test wells treated with DMSO only, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater % inhibition than the cutoff parameter was declared active.
PubChem Activity Outcome and Score:
The reported PubChem Activity Score has been normalized to 100% observed primary Inhibition. Negative % Inhibition values are reported as activity score zero.
The PubChem Activity Score range for active compounds is 100-17, and for inactive compounds 17-0.
List of Reagents:
HEK cells (supplied by Assay Provider)
Cell Titer Glo (Promega, part G75729)
Doxorubicin (Sigma Chemical, part D1515)
BSA (Sigma, part A9647)
DMEM (Invitrogen, part 11965)
Phenol-red free DMEM (Invitrogen, part 21063)
FBS (Hyclone, part SH30088.03)
Pen/Step/Neo mix (Gibco, part 15640)
1536-well plates (Greiner, part 789176)
Due to the increasing size of the MLPCN compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. In this case the results of each separate campaign were assigned "Active/Inactive" status based upon that campaign's specific compound activity cutoff value. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, and compounds that quench or emit fluorescence within the well. All test compound concentrations reported are nominal; the specific concentration for a particular test compound may vary based upon the actual sample provided by the MLSMR. The MLSMR was not able to provide all compounds selected for testing in this AID.
Categorized Comment - additional comments and annotations
** Test Concentration.
Data Table (Concise)