Preeti Viswanathan1, Yogeshwar Sharma2, Priya Gupta2, Sanjeev Gupta2,3,4. 1. Division of Pediatric Gastroenterology and Hepatology, Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA. 2. Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA. 3. Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA. 4. Marion Bessin Liver Research Center, Diabetes Center, Irwin S. and Sylvia Chanin Institute for Cancer Research, Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, Albert Einstein College of Medicine, Bronx, NY, USA.
Abstract
OBJECTIVES: Acetaminophen hepatotoxicity is a leading cause of hepatic failure with impairments in liver regeneration producing significant mortality. Multiple intracellular events, including oxidative stress, mitochondrial damage, inflammation, etc., signify acetaminophen toxicity, although how these may alter cell cycle controls has been unknown and was studied for its significance in liver regeneration. MATERIALS AND METHODS: Assays were performed in HuH-7 human hepatocellular carcinoma cells, primary human hepatocytes and tissue samples from people with acetaminophen-induced acute liver failure. Cellular oxidative stress, DNA damage and cell proliferation events were investigated by mitochondrial membrane potential assays, flow cytometry, fluorescence staining, comet assays and spotted arrays for protein expression after acetaminophen exposures. RESULTS: In experimental groups with acetaminophen toxicity, impaired mitochondrial viability and substantial DNA damage were observed with rapid loss of cells in S and G2/M and cell cycle restrictions or even exit in the remainder. This resulted from altered expression of the DNA damage regulator, ATM and downstream transducers, which imposed G1/S checkpoint arrest, delayed entry into S and restricted G2 transit. Tissues from people with acute liver failure confirmed hepatic DNA damage and cell cycle-related lesions, including restrictions of hepatocytes in aneuploid states. Remarkably, treatment of cells with a cytoprotective cytokine reversed acetaminophen-induced restrictions to restore cycling. CONCLUSIONS: Cell cycle lesions following mitochondrial and DNA damage led to failure of hepatic regeneration in acetaminophen toxicity but their reversibility offers molecular targets for treating acute liver failure.
OBJECTIVES:Acetaminophenhepatotoxicity is a leading cause of hepatic failure with impairments in liver regeneration producing significant mortality. Multiple intracellular events, including oxidative stress, mitochondrial damage, inflammation, etc., signify acetaminophentoxicity, although how these may alter cell cycle controls has been unknown and was studied for its significance in liver regeneration. MATERIALS AND METHODS: Assays were performed in HuH-7humanhepatocellular carcinoma cells, primary human hepatocytes and tissue samples from people with acetaminophen-induced acute liver failure. Cellular oxidative stress, DNA damage and cell proliferation events were investigated by mitochondrial membrane potential assays, flow cytometry, fluorescence staining, comet assays and spotted arrays for protein expression after acetaminophen exposures. RESULTS: In experimental groups with acetaminophentoxicity, impaired mitochondrial viability and substantial DNA damage were observed with rapid loss of cells in S and G2/M and cell cycle restrictions or even exit in the remainder. This resulted from altered expression of the DNA damage regulator, ATM and downstream transducers, which imposed G1/S checkpoint arrest, delayed entry into S and restricted G2 transit. Tissues from people with acute liver failure confirmed hepatic DNA damage and cell cycle-related lesions, including restrictions of hepatocytes in aneuploid states. Remarkably, treatment of cells with a cytoprotective cytokine reversed acetaminophen-induced restrictions to restore cycling. CONCLUSIONS: Cell cycle lesions following mitochondrial and DNA damage led to failure of hepatic regeneration in acetaminophentoxicity but their reversibility offers molecular targets for treating acute liver failure.
Authors: Zurab Kakabadze; Lia Karalashvili; David Chakhunashvili; Necat Havlioglu; Merab Janelidze; Ann Kakabadze; Yogeshwar Sharma; Sanjeev Gupta Journal: Mater Sci Eng C Mater Biol Appl Date: 2018-12-10 Impact factor: 7.328