title: Iterative Focused Screening with Biological Fingerprints Identifies Selective Asc-1 Inhibitors Distinct from Traditional High Throughput Screening.
abstract: N-methyl-d-aspartate receptors (NMDARs) mediate glutamatergic signaling that is critical to cognitive processes in the central nervous system, and NMDAR hypofunction is thought to contribute to cognitive impairment observed in both schizophrenia and Alzheimer's disease. One approach to enhance the function of NMDAR is to increase the concentration of an NMDAR coagonist, such as glycine or d-serine, in the synaptic cleft. Inhibition of alanine-serine-cysteine transporter-1 (Asc-1), the primary transporter of d-serine, is attractive because the transporter is localized to neurons in brain regions critical to cognitive function, including the hippocampus and cortical layers III and IV, and is colocalized with d-serine and NMDARs. To identify novel Asc-1 inhibitors, two different screening approaches were performed with whole-cell amino acid uptake in heterologous cells stably expressing human Asc-1: (1) a high-throughput screen (HTS) of 3 M compounds measuring35S l-cysteine uptake into cells attached to scintillation proximity assay beads in a 1536 well format and (2) an iterative focused screen (IFS) of a 45 000 compound diversity set using a3H d-serine uptake assay with a liquid scintillation plate reader in a 384 well format. Critically important for both screening approaches was the implementation of counter screens to remove nonspecific inhibitors of radioactive amino acid uptake. Furthermore, a 15 000 compound expansion step incorporating both on- and off-target data into chemical and biological fingerprint-based models for selection of additional hits enabled the identification of novel Asc-1-selective chemical matter from the IFS that was not identified in the full-collection HTS.
authors.affiliation: Modeling and Informatics, Merck & Co., Inc., MRL , Boston, Massachusetts, United States.
authors.forename: Peter S
authors.identifier: 0000-0002-5684-1971
authors.initials: PS
authors.lastname: Kutchukian
authors.affiliation: Neuroscience, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Lee
authors.initials: L
authors.lastname: Warren
authors.affiliation: Pharmacology, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Magliaro
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Adam
authors.initials: A
authors.lastname: Amoss
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Cassaday
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Gregory
authors.initials: G
authors.lastname: O'Donnell
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Brian
authors.initials: B
authors.lastname: Squadroni
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Zuck
authors.affiliation: Pharmacology, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Danette
authors.initials: D
authors.lastname: Pascarella
authors.affiliation: Modeling and Informatics, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: J Chris
authors.initials: JC
authors.lastname: Culberson
authors.affiliation: Chemistry, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cooke
authors.affiliation: Chemistry, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Danielle
authors.initials: D
authors.lastname: Hurzy
authors.affiliation: Chemistry, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Kelly-Ann Sondra
authors.initials: KS
authors.lastname: Schlegel
authors.affiliation: Neuroscience, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Fiona
authors.identifier: 0000-0002-8987-5369
authors.initials: F
authors.lastname: Thomson
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Eric N
authors.initials: EN
authors.lastname: Johnson
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Victor N
authors.initials: VN
authors.lastname: Uebele
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Hermes
authors.affiliation: Neuroscience, Merck & Co., Inc., MRL , West Point, Pennsylvania, United States.
authors.forename: Sophie
authors.initials: S
authors.lastname: Parmentier-Batteur
authors.affiliation: Screening and Protein Sciences, Merck & Co., Inc., MRL , North Wales, Pennsylvania, United States.
authors.forename: Michael
authors.identifier: 0000-0002-5547-5519
authors.initials: M
authors.lastname: Finley
mesh_terms: D027182:Amino Acid Transport System y+ / Q000037:antagonists & inhibitors*; D000818:Animals; D001499:Bayes Theorem; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D057166:High-Throughput Screening Assays; D006801:Humans; D000069550:Machine Learning
chemical_list: D027182:Amino Acid Transport System y+; C498799:SLC7A10 protein, human