FRET-Based Screening Identifies p38 MAPK and PKC Inhibition as Targets for Prevention of Seeded α-Synuclein Aggregation

Neurotherapeutics. 2021 Jul;18(3):1692-1709. doi: 10.1007/s13311-021-01070-1. Epub 2021 Jul 13.

Abstract

Aggregation of α-synuclein is associated with neurodegeneration and a hallmark pathology in synucleinopathies. These aggregates are thought to function as prion-like particles where the conformation of misfolded α-synuclein determines the traits of the induced pathology, similar to prion diseases. Still, little is known about the molecular targets facilitating the conformation-specific biological effects, but their identification could form the basis for new therapeutic interventions. High-throughput screening of annotated compound libraries could facilitate mechanistic investigation by identifying targets with impact on α-synuclein aggregation. To this end, we developed a FRET-based cellular reporter in HEK293T cells, with sensitivity down to 6.5 nM α-synuclein seeds. Using this model system, we identified GF109203X, SB202190, and SB203580 as inhibitors capable of preventing induction of α-synuclein aggregation via inhibition of p38 MAPK and PKC, respectively. We further investigated the mechanisms underlying the protective effects and found alterations in the endo-lysosomal system to be likely candidates of the protection. We found the changes did not stem from a reduction in uptake but rather alteration of lysosomal abundance and degradative capacity. Our findings highlight the value high-throughput screening brings to the mechanistic investigation of α-synuclein aggregation while simultaneously identifying novel therapeutic compounds.

Keywords: Endosome; FRET; High-throughput screening; Kinase; Lysosome; Proteomics; α-Synuclein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Cultured
  • Drug Delivery Systems / methods
  • Enzyme Inhibitors / administration & dosage*
  • Fluorescence Resonance Energy Transfer / methods*
  • HEK293 Cells
  • Humans
  • Imidazoles / administration & dosage
  • Protein Aggregation, Pathological / drug therapy
  • Protein Aggregation, Pathological / metabolism*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Proteome / drug effects
  • Proteome / metabolism
  • Pyridines / administration & dosage
  • alpha-Synuclein / metabolism*
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • p38 Mitogen-Activated Protein Kinases / metabolism*

Substances

  • Enzyme Inhibitors
  • Imidazoles
  • Proteome
  • Pyridines
  • SNCA protein, human
  • alpha-Synuclein
  • Protein Kinase C
  • p38 Mitogen-Activated Protein Kinases
  • 4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole