Project description:In inflammatory diseases of the airway, a high level (estimated to be as high as 8 mM) of HOCl can be generated through a reaction catalyzed by the leukocyte granule enzyme myeloperoxidase (MPO). HOCl, a potent oxidative agent, causes extensive tissue injury through its reaction with various cellular substances, including thiols, nucleotides, and amines. In addition to its physiological source, HOCl can also be generated by chlorine gas inhalation from an accident or a potential terrorist attack. Despite the important role of HOCl-induced airway epithelial injury, the underlying molecular mechanism is largely unknown. In the present study, we found that HOCl induced dose-dependent toxicity in airway epithelial cells. By transcription profiling using GeneChip, we identified a battery of HOCl-inducible antioxidant genes, all of which have been reported previously to be regulated by nuclear factor erythroid-related factor 2 (Nrf2), a transcription factor that is critical to the lung antioxidant response. Consistent with this finding, Nrf2 was found to be activated time and dose dependently by HOCl. Although the epidermal growth factor receptor-MAPK pathway was also highly activated by HOCl, it was not involved in Nrf2 activation and Nrf2-dependent gene expression. Instead, HOCl-induced cellular oxidative stress appeared to lead directly to Nrf2 activation. To further understand the functional significance of Nrf2 activation, small interference RNA was used to knock down Nrf2 level by targeting Nrf2 or enhance nuclear accumulation of Nrf2 by targeting its endogenous inhibitor Keap1. By both methods, we conclude that Nrf2 directly protects airway epithelial cells from HOCl-induced toxicity.
Project description:Hypochlorous acid (HOCl) is a potent oxidant that is produced endogenously in mammalian tissue by phagocytes. Exogenous exposure to HOCl also can occur following inhalation of chlorine gas. HOCl has been implicated as a source of oxidative stress associated atherosclerosis and other diseases. The purpose of this study was to identify dose-dependent transitions in cellular response to hypochlorous acid (HOCl), with a focus on understanding how various cellular defense and stress dose-responses overlap.
Project description:In inflammatory diseases of the airway, a high level (estimated to be as high as 8 mM) of HOCl can be generated through a reaction catalyzed by the leukocyte granule enzyme myeloperoxidase (MPO). HOCl, a potent oxidative agent, causes extensive tissue injury through its reaction with various cellular substances, including thiols, nucleotides, and amines. In addition to its physiological source, HOCl can also be generated by chlorine gas inhalation from an accident or a potential terrorist attack. Despite the important role of HOCl-induced airway epithelial injury, the underlying molecular mechanism is largely unknown. In the present study, we found that HOCl induced dose-dependent toxicity in airway epithelial cells. By transcription profiling using GeneChip, we identified a battery of HOCl-inducible antioxidant genes, all of which have been reported previously to be regulated by nuclear factor erythroid-related factor 2 (Nrf2), a transcription factor that is critical to the lung antioxidant response. Consistent with this finding, Nrf2 was found to be activated time and dose dependently by HOCl. Although the epidermal growth factor receptor-MAPK pathway was also highly activated by HOCl, it was not involved in Nrf2 activation and Nrf2-dependent gene expression. Instead, HOCl-induced cellular oxidative stress appeared to lead directly to Nrf2 activation. To further understand the functional significance of Nrf2 activation, small interference RNA was used to knock down Nrf2 level by targeting Nrf2 or enhance nuclear accumulation of Nrf2 by targeting its endogenous inhibitor Keap1. By both methods, we conclude that Nrf2 directly protects airway epithelial cells from HOCl-induced toxicity. Experiment Overall Design: This is genechip study. Detailed study design is described in: Am J Physiol Lung Cell Mol Physiol. 2008 Mar;294(3):L469-77. Epub 2007 Dec 21.
Project description:Galectin-1 (Gal-1) and Galectin-3 (Gal-3) are conserved carbohydrate-binding proteins that also display RNA-binding activity. We generated mouse embryonic stem cells (mESC) constitutively depleted of Gal-1 and/or Gal-3 using CRISPR-Cas9, and assessed the transcriptomic effects of the individual or concomitant depletion of Gal-1 and Gal-3 in mESCs differentiated by deprivation of the leukaemia inhibitory factor (LIF) for 7 days. Wild-type cells were employed as control.
Project description:RNA sequencing of Escherichia coli Nissle 1917 before and after HOCl treatment was perfomed to identify pathways that may be important in responding to oxidative stress caused by reachive chlorine species (RCS).
Project description:We evaluated the changes in the transcriptome of a melanoma cell line, B16F10, and spleen isolated murine T cells when in the presence of hypochlorous acid (HOCl) using RNA-sequencing technologies.
Project description:The biogenesis of iron-sulfur proteins in eukaryotes is an essential process involving the mitochondrial iron-sulfur cluster (ISC) assembly and export machineries and the cytosolic Fe/S protein assembly (CIA) apparatus. To define the integration of Fe/S protein biogenesis into cellular homeostasis, we compared the global transcriptional responses to defects in the three biogenesis systems in S. cerevisiae using DNA microarrays. Microarray analyses were carried out with regulatable yeast mutants in which representatives of each of the three biosynthetic systems could be depleted. In particular, we used the mutants Gal-YAH1, Gal-ATM1 and Gal-NBP35.