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Updated: May 16, 2026
Induction of Drug-Induced, Autoimmune Hepatitis in BALB/c Mice for the Study of Its Pathogenic Mechanisms
Published on: May 29, 2020
Chlorpromazine-induced hepatotoxicity during inflammation is mediated by TIRAP-dependent signaling pathway in mice
Adarsh Gandhi1, Tao Guo, Pranav Shah
1University of Houston, Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, 1441 Moursund Street, Room 517, Houston, TX 77030, USA. adarsh.gandhi@nih.gov
Abstract:
Inflammation is a major component of idiosyncratic adverse drug reactions (IADRs). To understand the molecular mechanism of inflammation-mediated IADRs, we determined the role of the Toll-like receptor (TLR) signaling pathway in idiosyncratic hepatotoxicity of the anti-psychotic drug, chlorpromazine (CPZ). Activation of TLRs recruits the first adaptor protein, Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP) to the TIR domain of TLRs leading to the activation of the downstream kinase, c-Jun-N-terminal kinase (JNK). Prolonged activation of JNK leads to cell-death. We hypothesized that activation of TLR2 by lipoteichoic acid (LTA) or TLR4 by lipopolysaccharide (LPS) will augment the hepatotoxicity of CPZ by TIRAP-dependent mechanism involving prolonged activation of JNK. Adult male C57BL/6, TIRAP(+/+) and TIRAP(-/-) mice were pretreated with saline, LPS (2 mg/kg) or LTA (6 mg/kg) for 30 min or 16 h followed by CPZ (5 mg/kg) or saline (vehicle) up to 24h. We found that treatment of mice with CPZ in presence of LPS or LTA leads to ~3-4 fold increase in serum ALT levels, a marked reduction in hepatic glycogen content, significant induction of serum tumor necrosis factor (TNF) α and prolonged JNK activation, compared to LPS or LTA alone. Similar results were observed in TIRAP(+/+) mice, whereas the effects of LPS or LTA on CPZ-induced hepatotoxicity were attenuated in TIRAP(-/-) mice. For the first time, we show that inflammation-mediated hepatotoxicity of CPZ is dependent on TIRAP, and involves prolonged JNK activation in vivo. Thus, TIRAP-dependent pathways may be targeted to predict and prevent inflammation-mediated IADRs.
Insights
Inflammation contributes to drug reactions. This study reveals Toll-like receptor 2/4 (TLR2/4) activation exacerbates chlorpromazine (CPZ) liver injury via TIRAP, prolonging JNK activation and leading to cell death.
Area of Science:
- Pharmacology
- Immunology
- Hepatology
Background:
- Inflammation is a key factor in idiosyncratic adverse drug reactions (IADRs).
- Toll-like receptor (TLR) signaling pathways, involving adaptor proteins like TIRAP and kinases such as JNK, play a role in inflammatory responses.
- Understanding these pathways is crucial for elucidating drug-induced liver injury mechanisms.
Purpose of the Study:
- To investigate the role of the TLR signaling pathway, specifically TIRAP, in chlorpromazine (CPZ)-induced idiosyncratic hepatotoxicity.
- To determine if TLR2 or TLR4 activation augments CPZ hepatotoxicity through a TIRAP-dependent mechanism involving JNK activation.
Main Methods:
- Utilized adult male C57BL/6 mice, including TIRAP(+/+) and TIRAP(-/-) genotypes.
- Administered lipopolysaccharide (LPS) or lipoteichoic acid (LTA) to activate TLR4 or TLR2, respectively, followed by CPZ administration.
- Assessed serum alanine aminotransferase (ALT) levels, hepatic glycogen content, tumor necrosis factor-alpha (TNF-α) induction, and JNK activation.
Main Results:
- CPZ treatment combined with LPS or LTA significantly increased serum ALT levels and reduced hepatic glycogen content compared to LPS or LTA alone.
- This combination therapy led to prolonged JNK activation and induced TNF-α, effects observed in TIRAP(+/+) mice.
- Hepatotoxicity and JNK activation induced by LPS/LTA and CPZ were significantly attenuated in TIRAP(-/-) mice.
Conclusions:
- Hepatotoxicity of CPZ exacerbated by inflammation (via TLR2/4 activation) is dependent on the adaptor protein TIRAP.
- The mechanism involves prolonged JNK activation in vivo.
- Targeting TIRAP-dependent pathways could offer a strategy for predicting and preventing inflammation-mediated IADRs.
