Unveiling the Cellular Mystery of Isoniazid–Rifampicin (IR) in CYP2E1 Overexpressing HepG2 Cells
- 1Department of Basic Science and Disease Biology John C. Martin Center for Liver Research and Innovations Kolkata India
- 2Department of Hepatology School of Digestive and Liver Diseases School of Digestive and Liver Diseases Institute of Post Graduate Medical Education & Research Kolkata India ipgmer.gov.in
- 3Department of Gastroenterology School of Digestive and Liver Diseases Institute of Post Graduate Medical Education & Research Kolkata India ipgmer.gov.in
Abstract
Background and Aims: The molecular basis of liver injury observed following cotreatment with the first‐line antitubercular drugs (ATDs) isoniazid (INH) and rifampicin (RIF) is not fully understood. Cytochrome P450 2E1 (CYP2E1), a key enzyme in drug metabolism, is thought to contribute to INH‐RIF (IR)–associated hepatotoxicity. In this study, we investigated the intracellular events, including lysosomal and mitochondrial alterations, that occur in CYP2E1 overexpressing HepG2 (HepG2‐E47) cells during IR exposure.
Methods: HepG2‐E47 cells overexpressing CYP2E1 were cotreated with 5 μM INH and 2.5 μM RIF for various time points. Reactive oxygen species (ROS) generation, antioxidant defense status, and CYP2E1 activity were assessed. Lysosomal destabilization, mitochondrial depolarization, and cell death were analyzed using fluorescence spectrophotometer and flow cytometry. To explore CYP2E1 involvement, cells were pretreated with the selective CYP2E1 inhibitor chlormethiazole (CMZ). Pharmacological modulators were used to explore the role of lysosomal and mitochondrial involvement following IR treatment.
Results: IR treatment significantly enhanced CYP2E1 activity, ROS production, and impairment of the cellular antioxidant system. These effects were prevented by CMZ, indicating CYP2E1‐dependent oxidative stress. Increased ROS in hepatocytes was accompanied by an early lysosomal dysfunction and cathepsin D release, which were followed by mitochondrial depolarization and apoptosis of the cells. Treatment with bafilomycin, a pharmacological modulator of lysosomal function, alleviated mitochondrial damage, consistent with lysosomal destabilization preceding mitochondrial dysfunction.
Conclusion: CYP2E1 plays a pivotal role in IR‐associated cellular injury in CYP2E1 overexpressing HepG2 cells by driving oxidative stress that triggers lysosomal and mitochondrial dysfunction leading to apoptosis. Targeting CYP2E1 or its downstream signalling pathways may provide therapeutic potential against ATD‐associated liver injury.
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BibTeX
@article{bishnu2026unveiling,
title = {{Unveiling the Cellular Mystery of Isoniazid–Rifampicin (IR) in CYP2E1 Overexpressing HepG2 Cells}},
author = {Debasree Bishnu and Suman Santra and Partha Sarathi Mukherjee and Gopal Krishna Dhali and Abhijit Chowdhury and Amal Santra},
journal = {International Journal of Hepatology},
year = {2026},
month = nov,
doi = {10.1155/ijh/9275461},
url = {https://doi.org/10.1155/ijh/9275461},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Unveiling the Cellular Mystery of Isoniazid–Rifampicin (IR) in CYP2E1 Overexpressing HepG2 Cells
AU - Debasree Bishnu
AU - Suman Santra
AU - Partha Sarathi Mukherjee
AU - Gopal Krishna Dhali
AU - Abhijit Chowdhury
AU - Amal Santra
PY - 2026
DA - 2026/11/03
JO - International Journal of Hepatology
DO - 10.1155/ijh/9275461
UR - https://doi.org/10.1155/ijh/9275461
AB - Background and Aims: The molecular basis of liver injury observed following cotreatment with the first‐line antitubercular drugs (ATDs) isoniazid (INH) and rifampicin (RIF) is not fully understood. Cytochrome P450 2E1 (CYP2E1), a key enzyme in drug metabolism, is thought to contribute to INH‐RIF (IR)–associated hepatotoxicity. In this study, we investigated the intracellular events, including lysosomal and mitochondrial alterations, that occur in CYP2E1 overexpressing HepG2 (HepG2‐E47) cells during IR exposure. Methods: HepG2‐E47 cells overexpressing CYP2E1 were cotreated with 5 μM INH and 2.5 μM RIF for various time points. Reactive oxygen species (ROS) generation, antioxidant defense status, and CYP2E1 activity were assessed. Lysosomal destabilization, mitochondrial depolarization, and cell death were analyzed using fluorescence spectrophotometer and flow cytometry. To explore CYP2E1 involvement, cells were pretreated with the selective CYP2E1 inhibitor chlormethiazole (CMZ). Pharmacological modulators were used to explore the role of lysosomal and mitochondrial involvement following IR treatment. Results: IR treatment significantly enhanced CYP2E1 activity, ROS production, and impairment of the cellular antioxidant system. These effects were prevented by CMZ, indicating CYP2E1‐dependent oxidative stress. Increased ROS in hepatocytes was accompanied by an early lysosomal dysfunction and cathepsin D release, which were followed by mitochondrial depolarization and apoptosis of the cells. Treatment with bafilomycin, a pharmacological modulator of lysosomal function, alleviated mitochondrial damage, consistent with lysosomal destabilization preceding mitochondrial dysfunction. Conclusion: CYP2E1 plays a pivotal role in IR‐associated cellular injury in CYP2E1 overexpressing HepG2 cells by driving oxidative stress that triggers lysosomal and mitochondrial dysfunction leading to apoptosis. Targeting CYP2E1 or its downstream signalling pathways may provide therapeutic potential against ATD‐associated liver injury.
SN - 2090-3448
SN - 2090-3456
ER -