Endoplasmic Reticulum Stress Induction and ERK1/2 Activation Contribute to Nefazodone-Induced Toxicity in Hepatic Cells.
Nefazodone, an antagonist for the 5-hydroxytryptanine receptor, has been used for the treatment of depression. Acute liver injury has been documented to be associated with the use of nefazodone; however, the mechanisms of nefazodone-induced liver toxicity are not well defined. In this report, using biochemical and molecular analyses, we characterized the molecular mechanisms underlying the hepatotoxicity of nefazodone. We found that nefazodone induced endoplasmic reticulum (ER) stress in HepG2 cells, as the expression of typical ER stress markers, including CHOP, ATF-4, and p-eIF2α, was significantly increased, and splicing of XBP1 was observed. Nefazodone-suppressed protein secretion was evaluated using a Gaussia luciferase reporter assay that measures ER stress. The ER stress inhibitors (4-phenylbutyrate and salubrinal) and knockdown of ATF-4 gene attenuated nefazodone-induced ER stress and cytotoxicity. Nefazodone activated the MAPK signaling pathway, as indicated by increased phosphorylation of JNK, ERK1/2, and p38. Inhibition of ERK1/2 reduced ER stress caused by nefazodone. Taken together, our findings suggest that ER stress contributes to nefazodone-induced toxicity in HepG2 cells and that the MAPK signaling pathway plays an important role in ER stress.
Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas.
Zhen
Z
Ren
Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas.
Si
S
Chen
Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas.
Jie
J
Zhang
In Vitro ADMET Laboratories LLC, Columbia, Maryland.
Utkarsh
U
Doshi
In Vitro ADMET Laboratories LLC, Columbia, Maryland.
Albert P
AP
Li
Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. FDA, Jefferson, Arkansas; Lei.Guo@fda.hhs.gov.
Lei
L
Guo
D051701:Activating Transcription Factor 4 / Q000235:genetics / Q000378:metabolism; D018687:Antidepressive Agents, Second-Generation / Q000378:metabolism / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D051544:Cytochrome P-450 CYP3A / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D004789:Enzyme Activation; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010879:Piperazines; D034622:RNA Interference; D012326:RNA Splicing; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D051742:Transcription Factor CHOP / Q000378:metabolism; D014162:Transfection; D014230:Triazoles / Q000378:metabolism / Q000633:toxicity*; D000071717:X-Box Binding Protein 1 / Q000235:genetics / Q000378:metabolism
C497109:ATF4 protein, human; D018687:Antidepressive Agents, Second-Generation; C497249:DDIT3 protein, human; D015852:Eukaryotic Initiation Factor-2; D010879:Piperazines; D014230:Triazoles; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; D051701:Activating Transcription Factor 4; D051742:Transcription Factor CHOP; C051752:nefazodone; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3
MAPK pathway; drug-induced liver toxicity; endoplasmic reticulum stress (ER stress); nefazodone.; reporter gene assay