Modulating PCAF/GCN5 Immune Cell Function through a PROTAC Approach

ACS Chem Biol. 2018 Oct 19;13(10):2862-2867. doi: 10.1021/acschembio.8b00705. Epub 2018 Sep 18.

Abstract

P300/CBP-associated factor (PCAF) and general control nonderepressible 5 (GCN5) are closely related epigenetic proteins, each containing an acetyltransferase domain and a bromodomain. Consistent with reported roles for these proteins in immune function, we find that PCAF-deficient macrophages exhibit a markedly reduced ability to produce cytokines upon stimulation with lipopolysaccharide (LPS). Investigating the potential to target this pathway pharmacologically, we show that chemical inhibition of the PCAF/GCN5 bromodomains is insufficient to recapitulate the diminished inflammatory response of PCAF-deficient immune cells. However, by generating the first PCAF/GCN5 proteolysis targeting chimera (PROTAC), we identify small molecules able to degrade PCAF/GCN5 and to potently modulate the expression of multiple inflammatory mediators in LPS-stimulated macrophages and dendritic cells. Our data illustrate the power of the PROTAC approach in the context of multidomain proteins, revealing a novel anti-inflammatory therapeutic opportunity for targeting PCAF/GCN5.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Benzoates / chemical synthesis
  • Benzoates / chemistry
  • Benzoates / pharmacology*
  • Cell Differentiation / drug effects
  • Cytokines / metabolism
  • Dendritic Cells / metabolism
  • Humans
  • Inflammation / chemically induced
  • Inflammation / metabolism
  • Lipopolysaccharides
  • Macrophages / metabolism
  • Mice
  • Monocytes / metabolism
  • Peptide Hydrolases / metabolism
  • Piperidines / chemical synthesis
  • Piperidines / chemistry
  • Piperidines / pharmacology*
  • Protein Domains
  • Proteolysis
  • Pyridazines / chemical synthesis
  • Pyridazines / chemistry
  • Pyridazines / pharmacology*
  • Stereoisomerism
  • Ubiquitin-Protein Ligases
  • p300-CBP Transcription Factors / chemistry
  • p300-CBP Transcription Factors / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Benzoates
  • CRBN protein, human
  • Cytokines
  • Lipopolysaccharides
  • Piperidines
  • Pyridazines
  • p300-CBP Transcription Factors
  • p300-CBP-associated factor
  • Ubiquitin-Protein Ligases
  • Peptide Hydrolases