Identification of Anti-prion Compounds using a Novel Cellular Assay.
Prion diseases are devastating neurodegenerative disorders with no known cure. One strategy for developing therapies for these diseases is to identify compounds that block conversion of the cellular form of the prion protein (PrPC) into the infectious isoform (PrPSc). Most previous efforts to discover such molecules by high-throughput screening methods have utilized, as a read-out, a single kind of cellular assay system: neuroblastoma cells that are persistently infected with scrapie prions. Here, we describe the use of an alternative cellular assay based on suppressing the spontaneous cytotoxicity of a mutant form of PrP (Δ105-125). Using this assay, we screened 75,000 compounds, and identified a group of phenethyl piperidines (exemplified by LD7), which reduces the accumulation of PrPScin infected neuroblastoma cells by >90% at low micromolar doses, and inhibits PrPSc-induced synaptotoxicity in hippocampal neurons. By analyzing the structure-activity relationships of 35 chemical derivatives, we defined the pharmacophore of LD7, and identified a more potent derivative. Active compounds do not alter total or cell-surface levels of PrPC, and do not bind to recombinant PrP in surface plasmon resonance experiments, although at high concentrations they inhibit PrPSc-seeded conversion of recombinant PrP to a misfolded state in an in vitro reaction (RT-QuIC). This class of small molecules may provide valuable therapeutic leads, as well as chemical biological tools to identify cellular pathways underlying PrPScmetabolism and PrPCfunction.
From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
Thibaut
http://orcid.org/0000-0002-0818-2617
T
Imberdis
From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
James T
JT
Heeres
the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and.
Han
H
Yueh
From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
Cheng
C
Fang
the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and.
Jessie
J
Zhen
From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
Celeste B
CB
Rich
the Laboratory for Drug Discovery in Neurodegeneration, Brigham and Women's Hospital, Harvard Medical School, Cambridge, Massachusetts 02139.
Marcie
M
Glicksman
the Department of Chemistry, Boston University, Boston, Massachusetts 02115, and.
Aaron B
AB
Beeler
From the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, daharris@bu.edu.
David A
DA
Harris
D045744:Cell Line, Tumor; D057809:HEK293 Cells; D006801:Humans; D010880:Piperidines / Q000737:chemistry* / Q000494:pharmacology*; D018620:PrPSc Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D020349:Surface Plasmon Resonance / Q000379:methods*
D010880:Piperidines; D018620:PrPSc Proteins
drug discovery; drug screening; neurodegeneration; neurological disease; prion; small molecule