Lung Lysyl Oxidase Regulation by Metal Ion Homeostasis

Summary

Principal Investigator: Wande Li
Abstract: PROJECT ABSTRACT. Lysyl oxidase (LO), a copper-(Cu) dependent enzyme, oxidizes peptidyl lysine residues in substrates, e.g., collagen, elastin and histone H1, essential for organization and stabilization of the extracellular matrix (ECM) and the cell nucleus. This enzyme has been identified as a tumor suppressor, for example, inhibiting transforming activity of ras, a proto oncogene. Thus, LO as an intra- and extracellular effector plays a critical role in human physiology and pathology. Chronic exposure of humans to cadmium (Cd), a heavy metal, either from occupational contamination or from cigarette smoke, induces emphysema and lung cancers. However, the mechanisms for Cd-elicited lung pathology remain poorly understood. LO as a metalloenzyme is susceptible to changes in cellular metal homeostasis. Previous studies by this lab investigating the phenotype change from Cd sensitive to Cd resistant of rat lung fibroblasts (RFL6) illustrated downregulation of LO by Cd at mRNA, protein and catalytic levels. Continuing studies further indicated that RFL6 cells in response to Cd displayed inhibition of LO transcription initiation and enhancement of LO mRNA decay both collectively contributing to decreased levels of steady-state LO mRNAs. These findings have led to a hypothesis that transcriptional control and regulation of the LO gene are critical targets for Cd insult and silencing of LO gene transcription by Cd is a key molecular basis for lung diseases. The overall goal of the proposed research is to test this hypothesis by achieving following specific aims: 1) to identify mechanisms for Cd silencing of the LO gene at the transcriptional level by examining Cd modulation of RNA polymerase II- directed LO pre-mRNA synthesis and processing, and of the LO promoter activation regulated by the core promoter;2) to identify mechanisms for Cd silencing of the LO gene at the transcriptional level by examining Cd modulation of the LO promoter activation regulated by metal and redox-sensitive transcription factors and their cognate cis-elements, and determining LO promoter methylation to provide evidence for Cd epigenetic damage to LO DNA;3) to identify mechanisms for Cd silencing of the LO gene at the posttranscriptional level by examining Cd effects on the 5'-capping and 3'-polyadenylation status of LO mRNA, and assessing Cd sensitive, LO mRNA stability-related cis-elements in the 3'-untranslation region and their corresponding binding proteins;and 4) to investigate biological consequences of Cd silencing of the LO gene in cell and animal models by examining effects of altered LO expression by Cd on substrate promoter activation and cell transformation in the cell model and assessing the active status of the major LO transcriptional and posttranscriptional machineries as well as aberrant methylation of the LO gene promoter in emphysematous and carcinogenic lungs of rats receiving Cd by chronic administration. The outcomes of the proposed research are expected to enhance our understanding of mechanisms of LO gene silence by Cd providing the basis for developing prophylaxis and treatment strategies for Cd-related lung diseases.
Funding Period: 2001-12-01 - 2014-04-30
more information: NIH RePORT

Top Publications

  1. ncbi Inhibition of the expression of lysyl oxidase and its substrates in cadmium-resistant rat fetal lung fibroblasts
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    Toxicol Sci 90:478-89. 2006
  2. ncbi Perturbation of copper (Cu) homeostasis and expression of Cu-binding proteins in cadmium-resistant lung fibroblasts
    Denise K Chou
    Department of Biochemistry, Boston University School of Medicine, MA 02118, USA
    Toxicol Sci 99:267-76. 2007
  3. ncbi Cloning and characterization of the rat lysyl oxidase gene promoter: identification of core promoter elements and functional nuclear factor I-binding sites
    Song Gao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    J Biol Chem 282:25322-37. 2007
  4. pmc The critical role of the cellular thiol homeostasis in cadmium perturbation of the lung extracellular matrix
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Toxicology 267:60-9. 2010
  5. pmc Bleomycin induces upregulation of lysyl oxidase in cultured human fetal lung fibroblasts
    Li Jun Chen
    Department of Pharmacology, Zhongshan School of Medicine, Sun Yat Sen University, Guangzhou 510089, China
    Acta Pharmacol Sin 31:554-9. 2010
  6. pmc LITAF and TNFSF15, two downstream targets of AMPK, exert inhibitory effects on tumor growth
    J Zhou
    Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
    Oncogene 30:1892-900. 2011
  7. pmc Lysyl oxidase, a critical intra- and extra-cellular target in the lung for cigarette smoke pathogenesis
    Wande Li
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Int J Environ Res Public Health 8:161-84. 2011
  8. pmc Microtubules as a critical target for arsenic toxicity in lung cells in vitro and in vivo
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Int J Environ Res Public Health 9:474-95. 2012
  9. pmc Hypoxia-response element (HRE)-directed transcriptional regulation of the rat lysyl oxidase gene in response to cobalt and cadmium
    Song Gao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    Toxicol Sci 132:379-89. 2013

Research Grants

Detail Information

Publications9

  1. ncbi Inhibition of the expression of lysyl oxidase and its substrates in cadmium-resistant rat fetal lung fibroblasts
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    Toxicol Sci 90:478-89. 2006
    ....
  2. ncbi Perturbation of copper (Cu) homeostasis and expression of Cu-binding proteins in cadmium-resistant lung fibroblasts
    Denise K Chou
    Department of Biochemistry, Boston University School of Medicine, MA 02118, USA
    Toxicol Sci 99:267-76. 2007
    ..These results suggest that downregulation of LO is linked with upregulation of other Cu-binding proteins and with alteration in Cu homeostasis in the CdR phenotype...
  3. ncbi Cloning and characterization of the rat lysyl oxidase gene promoter: identification of core promoter elements and functional nuclear factor I-binding sites
    Song Gao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    J Biol Chem 282:25322-37. 2007
    ..In conclusion, the isolated rat LO gene promoter contains functionally independent initiator and downstream core promoter elements, and the conserved NFI-binding sites play a critical role in the LO gene activation...
  4. pmc The critical role of the cellular thiol homeostasis in cadmium perturbation of the lung extracellular matrix
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Toxicology 267:60-9. 2010
    ..Thus, Cd upregulation of cellular thiols may be a critical cellular event facilitating downregulation of LO, a potential mechanism for Cd-induced emphysema...
  5. pmc Bleomycin induces upregulation of lysyl oxidase in cultured human fetal lung fibroblasts
    Li Jun Chen
    Department of Pharmacology, Zhongshan School of Medicine, Sun Yat Sen University, Guangzhou 510089, China
    Acta Pharmacol Sin 31:554-9. 2010
    ..To investigate the mechanism of bleomycin (BLM)-induced pulmonary fibrosis...
  6. pmc LITAF and TNFSF15, two downstream targets of AMPK, exert inhibitory effects on tumor growth
    J Zhou
    Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
    Oncogene 30:1892-900. 2011
    ..Therefore, our studies for the first time establish the regulatory axis of AMPK-LITAF-TNFSF15 and also suggest that LITAF may function as a tumor suppressor...
  7. pmc Lysyl oxidase, a critical intra- and extra-cellular target in the lung for cigarette smoke pathogenesis
    Wande Li
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Int J Environ Res Public Health 8:161-84. 2011
    ..In view of multiple biological functions and regulation characteristics of the LO gene, molecular mechanisms for CS damage to lung LO and its role in emphysema and cancer pathogenesis are discussed in this review...
  8. pmc Microtubules as a critical target for arsenic toxicity in lung cells in vitro and in vivo
    Yinzhi Zhao
    Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
    Int J Environ Res Public Health 9:474-95. 2012
    ..Thus, tubulin sulfhydryls and MAPs are major molecular targets for As³⁺ damage to the lung triggering MT disassembly cascades...
  9. pmc Hypoxia-response element (HRE)-directed transcriptional regulation of the rat lysyl oxidase gene in response to cobalt and cadmium
    Song Gao
    Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
    Toxicol Sci 132:379-89. 2013
    ..Thus, modulation of the HRE activity by Co and Cd plays a critical role in LO gene transactivation...

Research Grants30

  1. Mechanisms of Adaptation to Exercise in Health and COPD
    Peter D Wagner; Fiscal Year: 2013
    ....
  2. MOLECULAR MECHANISMS OF COMPLEX MIXTURE TOXICITY
    Alvaro Puga; Fiscal Year: 2013
    ....
  3. Immune-Based Interventions Against Infectious Diseases
    Alan L Rothman; Fiscal Year: 2013
    ..3. Recruit promising junior investigators and provide mentoring by established NIH-funded researchers. 4. Support a multidisciplinary research program led by junior investigators in translational infectious diseases immunology. ..
  4. Expanding Excellence in Developmental Biology in Oklahoma
    Linda F Thompson; Fiscal Year: 2013
    ..abstract_text> ..
  5. Signaling in Inflammation, Stress, and Tumorigenesis
    GEORGE ROBERT STARK; Fiscal Year: 2013
    ..abstract_text> ..