A biochemical and NMR spectroscopic study of hydrazine in the isolated rat hepatocyte

Ghatineh, S.; Morgan, Winston A.; Preece, Nicholas E.; Timbrell, John A.

doi:10.1007/bf01981506

Cited by 22 publications

(8 citation statements)

References 25 publications

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“…As 1-ABT is also an N -acetyltransferase (NAT) inhibitor [ 28 ], these data indicate that it is unlikely that an acetylated or oxidative metabolite of either INH or EFV was a major contributor to the cell injury. Because hydrazine, a major hydrolytic metabolite of isoniazid, has been implicated in the hepatic toxicity of isoniazid [ 29–32 ], we hypothesized that hydrazine was the primary toxic species contributing to the cytotoxicity in this model. To test this hypothesis, we used bis- p -nitrophenyl phosphate (BNPP), a specific acylamidase inhibitor, to prevent hydrazine formation in cells exposed to INH.…”

Section: Resultsmentioning

confidence: 99%

Bypassing the compromised mitochondrial electron transport with methylene blue alleviates efavirenz/isoniazid-induced oxidant stress and mitochondria-mediated cell death in mouse hepatocytes

Lee

Boelsterli

2014

Redox Biology

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Efavirenz (EFV) is an anti-retroviral drug frequently combined with isoniazid (INH) to treat HIV-1/tuberculosis co-infected patients. Both drugs have been associated with idiosyncratic liver injury (DILI), but combined anti-retroviral and anti-tubercular therapy can increase the risk for DILI as compared to either drug class alone. Because both EFV and INH have been implicated in targeting mitochondria, we aimed at exploring whether the two drugs might cause synergistic effects on the electron transport chain. We found that EFV inhibited complex I activity in isolated mouse liver mitochondria (IC50 ˜30 μM), whereas hydrazine, a major metabolite of INH generated by acylamidase-mediated hydrolytic cleavage, inhibited complex II activity (IC50 ˜30 μM). Neither INH alone (≤1000 μM) nor EFV alone (≤30 μM) was able to induce cell injury in cultured mouse hepatocytes. However, combined EFV/INH exposure resulted in increased superoxide formation and peroxynitrite stress, leading to the opening of the cyclosporine A-insensitive mode of the mitochondrial permeability transition (mPT), and necrotic cell death. The peroxynitrite scavengers, CBA or Fe-TMPyP, protected against mPT induction and alleviated cell injury. The acylamidase inhibitor bis-p-nitrophenyl phosphate prevented cell injury, suggesting that hydrazine greatly contributed to the toxicity. Methylene blue, a redox-active alternative electron acceptor/donor that bypasses complex I/II, effectively protected against EFV/INH-induced toxicity. These data demonstrate that, in murine hepatocytes, the mitochondrial electron transport chain is a critical target of combined EFV/INH exposure, and that this drug combination can lead to peroxynitrite stress-induced mPT and hepatocellular necrosis. These results are compatible with the concept that underlying silent mitochondrial dysfunction may be a key susceptibility factor contributing to idiosyncratic drug-induced liver injury.

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Section: Resultsmentioning

confidence: 99%

Bypassing the compromised mitochondrial electron transport with methylene blue alleviates efavirenz/isoniazid-induced oxidant stress and mitochondria-mediated cell death in mouse hepatocytes

Lee

Boelsterli

2014

Redox Biology

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“…In cultured rat hepatocytes, hydrazine causes acute toxicity in a concentration‐dependent manner, characterized by glutathione depletion, increase in glutathione disulfide, loss of catalase activity, and lactate dehydrogenase release . Also, hydrazine depletes the levels of pyridine nucleotides in cultured rat hepatocytes . The in vitro concentrations used to elicit these effects (low millimolar range) are clearly high and greater than the plasma concentrations measured in patients; however, the repeated and/or cumulative effects of even low levels of hydrazine in the liver are not known.…”

Section: Mechanisms Underlying Inh‐induced Liver Injurymentioning

confidence: 99%

“…40 Also, hydrazine depletes the levels of pyridine nucleotides in cultured rat hepatocytes. 41 The in vitro concentrations used to elicit these effects (low millimolar range) are clearly high and greater than the plasma concentrations measured in patients; however, the repeated and/or cumulative effects of even low levels of hydrazine in the liver are not known.…”

Section: Role Of Hydrazinementioning

confidence: 99%

“…With regards to a mechanistic explanation, earlier studies had found that in cultured rat hepatocytes exposed to hydrazine, the activity of succinate dehydrogenase was inhibited in a concentration-dependent manner. 41 While this suggests an effect of hydrazine on complex II and/or the TCA cycle, it was not clear whether the apparent inhibitory effect was due to a direct interaction with the enzyme complex or rather a consequence of cofactor or substrate depletion. Importantly, the temporal sequence of events indicated that decreased enzyme activity clearly preceded the loss of cell viability, suggesting that this may be a contributing cause, rather than the result of toxicity.…”

Section: Mitochondrial Toxicitymentioning

confidence: 99%

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Mechanisms of isoniazid‐induced idiosyncratic liver injury: Emerging role of mitochondrial stress

Boelsterli

Lee

2014

J of Gastro and Hepatol

117

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Idiosyncratic drug-induced liver injury (DILI) is a significant adverse effect of antitubercular therapy with isoniazid (INH). Although the drug has been used for many decades, the underlying mode of action (both patient-specific and drug-specific mechanisms) leading to DILI are poorly understood. Among the patient-specific determinants of susceptibility to INH-associated DILI, the importance of HLA genetic variants has been increasingly recognized, whereas the role of polymorphisms of drug-metabolizing enzymes (NAT2 and CYP2E1) has become less important and remains controversial. However, these polymorphisms are merely correlative, and other molecular determinants of susceptibility have remained largely unknown. Regarding the drug-specific mechanisms underlying INHinduced liver injury, novel concepts have been emerging. Among these are covalent protein adduct formation via novel reactive intermediates, leading to hapten formation and a potential immune response, and interference with endogenous metabolism. Furthermore, INH and/or INH metabolites (e.g. hydrazine) can cause mitochondrial injury, which can lead to mitochondrial oxidant stress and impairment of energy homeostasis. Recent studies have revealed that underlying impairment of complex I function can trigger massive hepatocellular injury induced by otherwise nontoxic concentrations of INH superimposed on these mitochondrial deficiencies. This review discusses these emerging new paradigms of INH-induced DILI and highlights recent insights into the mechanisms, as well as points to the existing large gaps in our understanding of the pathogenesis.

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“…Flutamide, an androgen, caused hepatitis in a few patients, which was attributed to a P450 catalysed reactive metabolite that inhibited hepatocyte mitochondrial complex I causing an inhibition of mitochondrial respiration and ATP depletion [181]. NMR spectroscopy was used to show that hydrazine, a minor metabolite of hydrazine drugs, inhibited succinate dehydrogenase when added to hepatocytes [182].…”

Section: B) Drugsmentioning

confidence: 99%

Mechanism of Mitochondrial Uncouplers, Inhibitors, and Toxins: Focus on Electron Transfer, Free Radicals, and Structure -Activity Relationships

Kovacic

Pozos²,

Somanathan³

et al. 2005

CMC

160

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The biology of the mitochondrial electron transport chain is summarized. Our approach to the mechanism of uncouplers, inhibitors, and toxins is based on electron transfer (ET) and reactive oxygen species (ROS). Extensive supporting evidence, which is broadly applicable, is cited. ROS can be generated either endogenously or exogenously. Generally, the reactive entities arise via redox cycling by ET functionalities, such as, quinones (or precursors), metal compounds, imines (or iminiums), and aromatic nitro compounds (or reduced metabolites). In most cases, the ET functions are formed metabolically. The toxic substances belong to many categories, e.g., medicinals, industrial chemicals, abused drugs, and pesticides. Structure-activity relationships are presented from the ET-ROS perspective, and also quantitatively. Evidence for the theoretical framework is provided by the protective effect of antioxidants. Among other topics addressed are proton flux, membrane pores, and apoptosis. There is support for the thesis that mitochondrial insult may contribute to illnesses and aging.

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A biochemical and NMR spectroscopic study of hydrazine in the isolated rat hepatocyte

Cited by 22 publications

References 25 publications

Bypassing the compromised mitochondrial electron transport with methylene blue alleviates efavirenz/isoniazid-induced oxidant stress and mitochondria-mediated cell death in mouse hepatocytes

Bypassing the compromised mitochondrial electron transport with methylene blue alleviates efavirenz/isoniazid-induced oxidant stress and mitochondria-mediated cell death in mouse hepatocytes

Mechanisms of isoniazid‐induced idiosyncratic liver injury: Emerging role of mitochondrial stress

Mechanism of Mitochondrial Uncouplers, Inhibitors, and Toxins: Focus on Electron Transfer, Free Radicals, and Structure -Activity Relationships

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