High-content screen for modifiers of Niemann-Pick type C disease in patient cells

Hum Mol Genet. 2018 Jun 15;27(12):2101-2112. doi: 10.1093/hmg/ddy117.

Abstract

Niemann-Pick type C (NPC) disease is a rare lysosomal storage disease caused primarily by mutations in NPC1. NPC1 encodes the lysosomal cholesterol transport protein NPC1. The most common NPC1 mutation is a missense mutation (NPC1I1061T) that causes misfolding and rapid degradation of mutant protein in the endoplasmic reticulum. Cholesterol accumulates in enlarged lysosomes as a result of decreased levels of lysosomal NPC1I1061T protein in patient cells. There is currently no cure or FDA-approved treatment for patients. We sought to identify novel compounds that decrease lysosomal cholesterol storage in NPC1I1061T/I1061T patient fibroblasts using a high-content screen with the cholesterol dye, filipin and the lysosomal marker, LAMP1. A total of 3532 compounds were screened, including 2013 FDA-approved drugs, 327 kinase inhibitors and 760 serum metabolites. Twenty-three hits were identified that decreased both filipin and LAMP1 signals. The majority of hits (16/21) were histone deacetylase (HDAC) inhibitors, a previously described class of modifiers of NPC cholesterol storage. Of the remaining hits, the antimicrobial compound, alexidine dihydrochloride had the most potent lysosomal cholesterol-reducing activity. Subsequent analyses showed that alexidine specifically increased levels of NPC1 transcript and mature protein in both control and NPC patient cells. Although unsuitable for systemic therapy, alexidine represents a unique tool compound for further NPC studies and as a potent inducer of NPC1. Together, these findings confirm the utility of high-content image-based compound screens of NPC1 patient cells and support extending the approach into larger compound collections.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biguanides / administration & dosage
  • Carrier Proteins / genetics*
  • Cholesterol / genetics*
  • Cholesterol / metabolism
  • Drug Evaluation, Preclinical
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / genetics
  • Fibroblasts / drug effects
  • Filipin / metabolism
  • Histone Deacetylase Inhibitors / administration & dosage*
  • Histone Deacetylase Inhibitors / isolation & purification
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Lysosomal-Associated Membrane Protein 1 / genetics
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Membrane Glycoproteins / genetics*
  • Metabolome / drug effects
  • Mutation, Missense
  • Niemann-Pick C1 Protein
  • Niemann-Pick Disease, Type C / drug therapy*
  • Niemann-Pick Disease, Type C / genetics
  • Niemann-Pick Disease, Type C / pathology

Substances

  • Biguanides
  • Carrier Proteins
  • Histone Deacetylase Inhibitors
  • Intracellular Signaling Peptides and Proteins
  • Lysosomal-Associated Membrane Protein 1
  • Membrane Glycoproteins
  • NPC1 protein, human
  • Niemann-Pick C1 Protein
  • Filipin
  • Cholesterol
  • alexidine