Caffeine disrupts ataxia telangiectasia mutated gene-related pathways and exacerbates acetaminophen toxicity in human fetal immortalized hepatocytes

Hepatocyte Transplantation Rebalances Cytokines for Hepatic Regeneration in Rats with Ataxia Telangiectasia Mutated Pathway-Related Acute Liver Failure

Inadequate DNA damage response related to ataxia telangiectasia mutated gene restricts hepatic regeneration in acute liver failure. Resolving mechanistic gaps in liver damage and repair requires additional animal models that are unconstrained by ultrarapid and unpredictable mortalities or substantial divergences from human pathology. This study used Fischer 344 rats primed with the antitubercular drug, rifampicin, plus phenobarbitone, and monocrotaline, a DNA adduct-forming alkaloid. Rifampicin and monocrotaline can cause liver failure in people. This regimen resulted in hepatic oxidative stress, necrosis, DNA double-strand breaks, liver test abnormalities, altered serum cytokine expression, and mortality. Healthy donor hepatocytes were transplanted ectopically in the peritoneal cavity to study whether they could supply metabolic support and rebalance inflammatory or protective cytokines affecting liver regeneration events. Hepatocyte transplantation increased candidate cytokine levels (granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interferon-γ, IL-10, and IL-12), leading to Atm, Stat3, and Akt signaling in hepatocytes and nonparenchymal cells, lowering of inflammation, and improvements in intermediary metabolism, DNA repair, and hepatocyte proliferation. Such control of DNA damage and inflammation, along with stimulation of hepatic growth, offers paradigms for cell signaling to restore hepatic homeostasis and regeneration in acute liver failure. Further studies of molecular pathways of high pathobiological impact will advance the knowledge of liver regeneration.

Potential Therapeutic Implication of Herbal Medicine in Mitochondria-Mediated Oxidative Stress-Related Liver Diseases

Mitochondria are double-membrane organelles that play a role in ATP synthesis, calcium homeostasis, oxidation-reduction status, apoptosis, and inflammation. Several human disorders have been linked to mitochondrial dysfunction. It has been found that traditional therapeutic herbs are effective on alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) which are leading causes of liver cirrhosis and hepatocellular carcinoma. The generation of reactive oxygen species (ROS) in response to oxidative stress is caused by mitochondrial dysfunction and is considered critical for treatment. The role of oxidative stress, lipid toxicity, and inflammation in NAFLD are well known. NAFLD is a chronic liver disease that commonly progresses to cirrhosis and chronic liver disease, and people with obesity, insulin resistance, diabetes, hyperlipidemia, and hypertension are at a higher risk of developing NAFLD. NAFLD is associated with a number of pathological factors, including insulin resistance, lipid metabolic dysfunction, oxidative stress, inflammation, apoptosis, and fibrosis. As a result, the improvement in steatosis and inflammation is enough to entice researchers to look into liver disease treatment. However, antioxidant treatment has not been very effective for liver disease. Additionally, it has been suggested that the beneficial effects of herbal medicines on immunity and inflammation are governed by various mechanisms for lipid metabolism and inflammation control. This review provided a summary of research on herbal medicines for the therapeutic implementation of mitochondria-mediated ROS production in liver disease as well as clinical applications through herbal medicine. In addition, the pathophysiology of common liver disorders such as ALD and NAFLD would be investigated in the role that mitochondria play in the process to open new therapeutic avenues in the management of patients with liver disease.

Transcriptional profiling reveals ataxia telangiectasia mutated pathways regulate joint copper and arsenic toxicity for hepatic metalloplasia and anti-cancer therapies

AIMS

Exposures to toxic metals, including arsenic (As), pose health risks but joint effects of physiologically needed metals, e.g., copper (Cu), are ill-defined for regulated metal-dependent cell proliferation (or metalloplasia). This study elucidated hepatic toxicities of As and Cu.

MAIN METHODS

Human HuH-7 cells were exposed to As and Cu and mRNA profiling obtained for molecular networks, regulators and signaling pathways. This followed biological testing of ATM signaling-related DNA damage response, mitochondrial dysfunction and lysosome activity using HuH-7 cells and primary hepatocytes. Free Cu ions were bound to 3-indole propionic acid for finding their contribution in toxicity.

KEY FINDINGS

The As or As plus Cu toxicities in HuH-7 cells produced dimorphic down- or up-regulation patterns in mRNA profiles. Significant differences extended for ontologies in protein synthesis, intermediary metabolism, mitochondrial function, autophagy, or cell survival and growth. Bioassays revealed ATM signaling regulated As and Cu toxicity for oxidative phosphorylation, mitochondrial membrane potential, lysosomal activity, DNA damage response, and cell growth-arrest. Removal of reactive Cu ions decreased As and Cu toxicity. Primary hepatocytes withstood Cu and As toxicity better.

SIGNIFICANCE

This joint As and Cu toxicity offers further mechanisms for metalloplasia, carcinogenesis and tissue damage in other settings, e.g., during excess Cu accumulation in Wilson disease. Moreover, joint As and Cu toxicities are relevant for anti-cancer therapies, potentially including manipulations to increase intracellular Cu through altered uptake or efflux processes and incorporating ATM-related checkpoint inhibitors. Superior tolerance of healthy hepatocytes to Cu and As toxicity should improve safety margins for anti-cancer therapies.