title: Computational identification of a phospholipidosis toxicophore using (13)C and (15)N NMR-distance based fingerprints.
abstract: Modified 3D-SDAR fingerprints combining (13)C and (15)N NMR chemical shifts augmented with inter-atomic distances were used to model the potential of chemicals to induce phospholipidosis (PLD). A curated dataset of 328 compounds (some of which were cationic amphiphilic drugs) was used to generate 3D-QSDAR models based on tessellations of the 3D-SDAR space with grids of different density. Composite PLS models averaging the aggregated predictions from 100 fully randomized individual models were generated. On each of the 100 runs, the activities of an external blind test set comprised of 294 proprietary chemicals were predicted and averaged to provide composite estimates of their PLD-inducing potentials (PLD+ if PLD is observed, otherwise PLD-). The best performing 3D-QSDAR model utilized a grid with a density of 8ppm×8ppm in the C-C region, 8ppm×20ppm in the C-N region and 20ppm×20ppm in the N-N region. The classification predictive performance parameters of this model evaluated on the basis of the external test set were as follows: accuracy=0.70, sensitivity=0.73 and specificity=0.66. A projection of the most frequently occurring bins on the standard coordinate space suggested a toxicophore composed of an aromatic ring with a centroid 3.5-7.5Å distant from an amino-group. The presence of a second aromatic ring separated by a 4-5Å spacer from the first ring and at a distance of between 5.5Å and 7Å from the amino-group was also associated with a PLD+ effect. These models provide comparable predictive performance to previously reported models for PLD with the added benefit of being based entirely on non-confidential, publicly available training data and with good predictive performance when tested in a rigorous, external validation exercise.
authors.affiliation: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA.
authors.forename: Svetoslav H
authors.initials: SH
authors.lastname: Slavov
authors.affiliation: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA.
authors.forename: Jon G
authors.initials: JG
authors.lastname: Wilkes
authors.affiliation: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA.
authors.forename: Dan A
authors.initials: DA
authors.lastname: Buzatu
authors.affiliation: Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Naomi L
authors.initials: NL
authors.lastname: Kruhlak
authors.affiliation: Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Willard
authors.affiliation: Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Hanig
authors.affiliation: Division of Systems Biology, National Center for Toxicological Research, US Food and Drug Administration, 3900 NCTR Rd., Jefferson, AR 72079, USA. Electronic address: Richard.Beger@fda.hhs.gov.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Beger
mesh_terms: D000465:Algorithms; D002247:Carbon Isotopes; D003878:Dermatoglyphics; D064420:Drug-Related Side Effects and Adverse Reactions; D009682:Magnetic Resonance Spectroscopy; D009587:Nitrogen Isotopes; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism*; D021281:Quantitative Structure-Activity Relationship; D013501:Surface-Active Agents / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D010743:Phospholipids; D013501:Surface-Active Agents
keywords: Fingerprint; Molecular modeling; Phospholipidosis; Quantitative spectral data–activity relationship (3D-QSDAR); Toxicophore