Dimethyl fumarate and monoethyl fumarate exhibit differential effects on KEAP1, NRF2 activation, and glutathione depletion in vitro

PLoS One. 2015 Mar 20;10(3):e0120254. doi: 10.1371/journal.pone.0120254. eCollection 2015.

Abstract

Delayed-release dimethyl fumarate (also known as gastro-resistant dimethyl fumarate), an oral therapeutic containing dimethyl fumarate (DMF) as the active ingredient, is currently approved for the treatment of relapsing multiple sclerosis. DMF is also a component in a distinct mixture product with 3 different salts of monoethyl fumarate (MEF), which is marketed for the treatment of psoriasis. Previous studies have provided insight into the pharmacologic properties of DMF, including modulation of kelch-like ECH-associated protein 1 (KEAP1), activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway, and glutathione (GSH) modulation; however, those of MEF remain largely unexplored. Therefore, the aim of this study was to evaluate the in vitro effects of DMF and MEF on KEAP1 modification, activation of the NRF2 pathway, and GSH conjugation. Using mass spectrometry, DMF treatment resulted in a robust modification of specific cysteine residues on KEAP1. In comparison, the overall degree of KEAP1 modification following MEF treatment was significantly less or undetectable. Consistent with KEAP1 cysteine modification, DMF treatment resulted in nuclear translocation of NRF2 and a robust transcriptional response in treated cells, as did MEF; however, the responses to MEF were of a lower magnitude or distinct compared to DMF. DMF was also shown to produce an acute concentration-dependent depletion of GSH; however, GSH levels eventually recovered and rose above baseline by 24 hours. In contrast, MEF did not cause acute reductions in GSH, but did produce an increase by 24 hours. Overall, these studies demonstrate that DMF and MEF are both pharmacologically active, but have differing degrees of activity as well as unique actions. These differences would be expected to result in divergent effects on downstream biology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytes / drug effects
  • Astrocytes / metabolism
  • Cell Nucleus / drug effects
  • Cell Nucleus / metabolism
  • Cysteine / metabolism
  • Dimethyl Fumarate / chemistry
  • Dimethyl Fumarate / pharmacology*
  • Extracellular Space / metabolism
  • Fumarates / chemistry
  • Fumarates / pharmacology*
  • Gene Expression Regulation / drug effects
  • Glutathione / metabolism*
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Kelch-Like ECH-Associated Protein 1
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism*
  • Protein Transport / drug effects

Substances

  • Fumarates
  • Intracellular Signaling Peptides and Proteins
  • KEAP1 protein, human
  • Kelch-Like ECH-Associated Protein 1
  • NF-E2-Related Factor 2
  • Dimethyl Fumarate
  • Glutathione
  • Cysteine
  • ethyl fumarate

Grant support

This study was funded by Biogen Idec, Inc. The authors had full editorial control of the content of manuscript, and all authors approved the content of the submitted manuscript. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.