Please use this identifier to cite or link to this item: https://doi.org/10.1016/j.taap.2006.08.001
Title: Leflunomide or A77 1726 protect from acetaminophen-induced cell injury through inhibition of JNK-mediated mitochondrial permeability transition in immortalized human hepatocytes
Authors: Latchoumycandane, C. 
Seah, Q.M.
Tan, R.C.H.
Boelsterli, U.A. 
Sattabongkot, J.
Beerheide, W.
Keywords: A77 1726
Acetaminophen
Cytoprotection
Hepatotoxicity
Immortalized human hepatocytes
JNK
Leflunomide
Mitochondria
Permeability transition
Issue Date: 2006
Source: Latchoumycandane, C., Seah, Q.M., Tan, R.C.H., Boelsterli, U.A., Sattabongkot, J., Beerheide, W. (2006). Leflunomide or A77 1726 protect from acetaminophen-induced cell injury through inhibition of JNK-mediated mitochondrial permeability transition in immortalized human hepatocytes. Toxicology and Applied Pharmacology 217 (1) : 125-133. ScholarBank@NUS Repository. https://doi.org/10.1016/j.taap.2006.08.001
Abstract: Leflunomide, a disease-modifying anti-rheumatic drug, protects against T-cell-mediated liver injury by poorly understood mechanisms. The active metabolite of leflunomide, A77 1726 (teriflunomide) has been shown to inhibit stress-activated protein kinases (JNK pathway), which are key regulators of mitochondria-mediated cell death. Therefore, we hypothesized that leflunomide may protect from drugs that induce the mitochondrial permeability transition (mPT) by blocking the JNK signaling pathway. To this end, we exposed cultured immortalized human hepatocytes (HC-04) to the standard protoxicant drug acetaminophen (APAP), which induces CsA-sensitive mPT-mediated cell death. We determined the effects of leflunomide on the extent of APAP-induced hepatocyte injury and the upstream JNK-mediated mitochondrial signaling pathways. We found that leflunomide or A77 1726 concentration-dependently protected hepatocytes from APAP (1 mM)-induced mitochondrial permeabilization and lethal cell injury. This was not due to proximal inhibition of CYP-catalyzed APAP bioactivation to its thiol-reactive metabolite. Instead, we demonstrate that leflunomide (20 μM) inhibited the APAP-induced early (3 h) activation (phosphorylation) of JNK1/2, thus inhibiting phosphorylation of the anti-apoptotic protein Bcl-2 and preventing P-Bcl-2-mediated induction of the mPT. This greatly attenuated mitochondrial cytochrome c release, which we used as a marker for mitochondrial permeabilization. The specific JNK2 inhibitor SP600125 similarly protected from APAP-induced cell death. In conclusion, these findings are consistent with our hypothesis that leflunomide protects from protoxicant-induced hepatocyte injury by inhibiting JNK signaling and preventing mPT induction. © 2006 Elsevier Inc. All rights reserved.
Source Title: Toxicology and Applied Pharmacology
URI: http://scholarbank.nus.edu.sg/handle/10635/27297
ISSN: 0041008X
10960333
DOI: 10.1016/j.taap.2006.08.001
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