title: Adverse effects of anti-tuberculosis drugs on HepG2 cell bioenergetics.
abstract: Tuberculosis (TB) is an intractable chronic infection. Disease treatment with anti-TB drugs remains challenging due to drug-induced hepatotoxicity. The toxicity of the anti-TB drugs rifampicin (RIF), isoniazid (INH) and pyrazinamide (PZA) either alone or in combination was investigated in HepG2 cells. Assays of intracellular adenosine triphosphate (ATP) levels at 4-, 24- and 48-h post-exposure to gradient concentrations of RIF, INH and PZA were conducted. Drug-induced effects on mitochondrial membrane potential (MMP), mitochondrial complex I and complex III activity, nicotinamide adenine dinucleotide (NAD+) levels and cellular lactate production were assessed. Decreased ATP levels were dose-dependent and correlated with drug exposure duration. Approximate 24-h IC50s were 0.5 mM, 70 mM and 84 mM for RIF, INH and PZA, respectively. Twenty-four hours post-drug treatment, reductions of MMP ( p = 0.0005), mitochondrial complex I and III activities ( p = 0.0001 and p = 0.0003, respectively), NAD+levels ( p = 0.0057) and increased lactate production ( p < 0.0001) were observed. Drug combinations used to mimic cumulative drug treatments induced a synergistic inhibition of mitochondrial complex I activity. An assessment of cellular ultrastructure using transmission electron microscopy indicated drug-induced mitophagy. Collectively, our study suggests that hepatotoxicity of commonly employed anti-TB drugs is mediated by their curtailment of mitochondrial function.
authors.affiliation: 1 Departments of Forensic Medicine and Clinical Toxicology, Mansoura University, Mansoura, Egypt.
authors.forename: E
authors.initials: E
authors.lastname: Elmorsy
authors.affiliation: 1 Departments of Forensic Medicine and Clinical Toxicology, Mansoura University, Mansoura, Egypt.
authors.forename: S M
authors.initials: SM
authors.lastname: Attalla
authors.affiliation: 1 Departments of Forensic Medicine and Clinical Toxicology, Mansoura University, Mansoura, Egypt.
authors.forename: E
authors.initials: E
authors.lastname: Fikry
authors.affiliation: 2 School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: A
authors.initials: A
authors.lastname: Kocon
authors.affiliation: 2 School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: R
authors.initials: R
authors.lastname: Turner
authors.affiliation: 3 School of Life Sciences, University of Nottingham, Nottingham, UK.
authors.forename: D
authors.initials: D
authors.lastname: Christie
authors.affiliation: 2 School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: A
authors.initials: A
authors.lastname: Warren
authors.affiliation: 4 Department of Experimental Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, University of Port Harcourt, Port Harcourt, Nigeria.
authors.forename: L L
authors.initials: LL
authors.lastname: Nwidu
authors.affiliation: 2 School of Medicine, University of Nottingham, Nottingham, UK.
authors.forename: W G
authors.initials: WG
authors.lastname: Carter
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000995:Antitubercular Agents / Q000633:toxicity*; D004347:Drug Interactions; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects*; D056945:Hep G2 Cells; D006801:Humans; D007538:Isoniazid / Q000633:toxicity*; D019344:Lactic Acid / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009243:NAD / Q000378:metabolism; D011718:Pyrazinamide / Q000633:toxicity*; D012293:Rifampin / Q000633:toxicity*
chemical_list: D000995:Antitubercular Agents; D009243:NAD; D011718:Pyrazinamide; D019344:Lactic Acid; D000255:Adenosine Triphosphate; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III; D007538:Isoniazid; D012293:Rifampin
keywords: Anti-TB drugs; drug-induced hepatotoxicity; mitochondrial complex I and complex III activity; mitochondrial membrane potential; mitophagy.