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Toxicology. 2018 Mar 1;396-397:33-45. doi: 10.1016/j.tox.2018.02.003. Epub 2018 Feb 8.

Mitochondrial dysfunction induced by leflunomide and its active metabolite.

Author information

1
Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
2
School of Pharmacy and School of Life Sciences, Fudan University, Shanghai 200438, China.
3
School of Pharmacy and School of Life Sciences, Fudan University, Shanghai 200438, China. Electronic address: Lei.Guo@fda.hhs.gov.

Abstract

Leflunomide, an anti-inflammatory drug used for the treatment of rheumatoid arthritis, has been marked with a black box warning regarding an increased risk of liver injury. The active metabolite of leflunomide, A771726, which also carries a boxed warning about potential hepatotoxicity, has been marketed as teriflunomide for the treatment of relapsing multiple sclerosis. Thus far, however, the mechanism of liver injury associated with the two drugs has remained elusive. In this study, cytotoxicity assays showed that ATP depletion and subsequent LDH release were induced in a time- and concentration-dependent manner by leflunomide in HepG2 cells, and to a lesser extent, by A77 1726. The decline of cellular ATP levels caused by leflunomide was dramatically exacerbated when galactose was substituted for glucose as the sugar source, indicating a potential mitochondrial liability of leflunomide. By measuring the activities of immuno-captured mitochondrial oxidative phosphorylation (OXPHOS) complexes, we found that leflunomide and A77 1726 preferentially targeted complex V (F1FO ATP synthase), with IC50 values of 35.0 and 63.7 μM, respectively. Bongkrekic acid, a mitochondrial permeability transition pore blocker that targets adenine nucleotide translocase, profoundly attenuated mitochondrial membrane depolarization, ATP depletion, and LDH leakage induced by leflunomide and A77 1726. Substantial alterations of mitochondrial function at the transcript level were observed in leflunomide-treated HepG2 cells, whereas the effects of A77 1726 on the cellular transcriptome were much less profound. Our results suggest that mitochondrial dysfunction may be implicated in the hepatotoxicity associated with leflunomide and A77 1726, with the former exhibiting higher toxicity potency.

KEYWORDS:

ANT; ATP synthase; Drug-induced liver injury; Leflunomide; Oxidative phosphorylation

PMID:
29427785
PMCID:
PMC5909954
DOI:
10.1016/j.tox.2018.02.003
[Indexed for MEDLINE]
Free PMC Article

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