Open AccessChemoproteomic profiling reveals that cathepsin D off-target activity drives ocular toxicity of β-secretase inhibitors
Author(s) -
Andrea M. Zuhl,
Charles E. Nolan,
Michael A. Brodney,
Sherry Niessen,
Kevin Atchison,
Christopher Houle,
David A. Karanian,
Claude Ambroise,
Jeffrey W. Brulet,
Elizabeth M. Beck,
Shawn D. Doran,
Brian T. O’Neill,
Christopher W. am Ende,
Cheng Chang,
Kieran F. Geoghegan,
Graham M. West,
Joshua C. Judkins,
Xinjun Hou,
David Riddell,
Douglas S. Johnson
Publication year - 2016
Publication title -
nature communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.559
H-Index - 365
ISSN - 2041-1723
DOI - 10.1038/ncomms13042
Subject(s) - toxicity , cathepsin , computational biology , proteomics , drug discovery , amyloid precursor protein secretase , in vivo , chemistry , amyloid precursor protein , biology , pharmacology , biochemistry , enzyme , alzheimer's disease , disease , medicine , genetics , organic chemistry , pathology , gene
Inhibition of β-secretase BACE1 is considered one of the most promising approaches for treating Alzheimer's disease. Several structurally distinct BACE1 inhibitors have been withdrawn from development after inducing ocular toxicity in animal models, but the target mediating this toxicity has not been identified. Here we use a clickable photoaffinity probe to identify cathepsin D (CatD) as a principal off-target of BACE1 inhibitors in human cells. We find that several BACE1 inhibitors blocked CatD activity in cells with much greater potency than that displayed in cell-free assays with purified protein. Through a series of exploratory toxicology studies, we show that quantifying CatD target engagement in cells with the probe is predictive of ocular toxicity in vivo . Taken together, our findings designate off-target inhibition of CatD as a principal driver of ocular toxicity for BACE1 inhibitors and more generally underscore the power of chemical proteomics for discerning mechanisms of drug action.