Molecular regulation of GM-CSF expression in alveolar epithelial cells

Summary

Principal Investigator: Robert Paine
Abstract: DESCRIPTION (provided by applicant): The pulmonary alveolar epithelium forms the largest surface of interaction of the human body with the external environment. Injury or disruption of normal function in alveolar epithelial cells (AEC) has important consequences for pulmonary gas exchange (resulting in acute lung injury), for determining normal or aberrant lung repair following lung injury, and for pulmonary innate immunity. Granulocyte-macrophage colony stimulating factor (GM-CSF) is an endogenous pulmonary cytokine produced by normal AEC that has emerged as a key defender of the lung. GM-CSF is protective against acute lung injury induced by oxidative stress and is an anti-apoptotic factor for AEC. Insults, such as exposure to bleomycin, that result in pulmonary fibrosis are associated with decreased AEC expression of GM-CSF;fibrosis is reduced following treatment with GM-CSF. GM-CSF is essential for normal function of alveolar macrophages, critical components of the pulmonary innate immunity that are also responsible for maintenance of normal surfactant homeostasis. Oxidative stress experienced by AEC in the setting of lung injury leads to impaired AEC GM-CSF expression and increased susceptibility to lethal pneumonia. This process is reversed by treatment with GM-CSF. Despite these protective effects, GM-CSF occupies a complex niche, with suggestions that inappropriate expression may contribute to pathologic inflammatory states such as rheumatoid arthritis or COPD. Our data demonstrate that regulation of GM-CSF expression in the alveolar epithelium differs in fundamental ways from regulation of this growth factor in other cells. Thus it is essential to understand the details of regulation of this pluripotent cytokine in the alveolar epithelium. Because lung epithelial cell lines poorly replicate the pattern of expression of GM-CSF by primary AEC, it is important to study the regulation of GM-CSF expression in primary AEC and to extend these studies to the intact lung. We hypothesize that AEC GM-CSF expression is regulated both post-transcriptionally and at the level of transcription. This proposal will examine both of these components in detail. Our preliminary studies indicate that mRNA stability is an important determinant of GM-CSF expression in the setting of oxidative stress. We have identified a group of microRNAs (miRNAs) whose behavior suggests that they are candidates to participate in GM-CSF mRNA destabilization in the setting of oxidative stress and have confirmed our ability to manipulate miRNA in primary murine AEC using lentviral transduction. Specific Aim 1 of this proposal will determine the regulatory roles of these miRNA, using a reporter construct for the GM-CSF 3'untranslated region and miRNA mimics and knockdown. We also have evidence that a zinc finger protein, ZFP36 or tristetraprolin (TTP), may contribute to GM-CSF mRNA degradation. Specific Aim 2 will define the role of TTP in the regulation of GM-CSF mRNA stability in AEC, with particular reference to miRNA effects on TTP expression. Specific Aim 3 will define the contribution of chromosomal accessibility and histone acetylation in determining the pattern of GM-CSF transcription in normal AEC and in the setting of injury and repair. These studies will determine critical features of the regulation of GM-CSF expression in a key cell type, the alveolar epithelial cell, and are essential for understanding th biology of GM-CSF in the contexts of defense of, and diseases of the human lung. They will offer the opportunity for targeted manipulation of endogenous GM-CSF expression within the alveolar space to promote normal repair following lung injury and restore or augment pulmonary host defense against pneumonia. Thus, they have the potential to provide new therapeutic approaches to restore alveolar epithelial integrity while limiting unintended adverse effects.
Funding Period: 2013-04-01 - 2017-03-31
more information: NIH RePORT

Research Grants

  1. Role for Wnt/beta-catenin signaling in alveolar repair and fibrosis
    Cara J Gottardi; Fiscal Year: 2013
  2. South Carolina IDeA Network of Biomedical Research Excellence
    LUCIA AMELIA PIRISI-CREEK; Fiscal Year: 2013
  3. Molecular mechanisms of hypoxia tolerance and susceptibility
    Gabriel G Haddad; Fiscal Year: 2013
  4. GENE THERAPY USING HEMATOPOIETIC STEM CELLS
    Donald B Kohn; Fiscal Year: 2013
  5. Mitochondrial Target for Radiation Mitigation
    Joel S Greenberger; Fiscal Year: 2013
  6. Mechanisms of beta-catenin signaling in alveolar epithelial cell differentiation
    Michael Kahn; Fiscal Year: 2013
  7. Developmental Exposure Alcohol Research Center
    Linda Patia Spear; Fiscal Year: 2013
  8. ADAPTATIONS TO HYPOXIA
    Kurt R Stenmark; Fiscal Year: 2013
  9. Zinc deficiency in the alcoholic lung
    Pratibha C Joshi; Fiscal Year: 2013
  10. Novel Molecular Mechanisms Promote GPCR-Induced Bronchodilation in Asthma
    REYNOLD ALEXANDER PANETTIERI; Fiscal Year: 2013

Detail Information

Research Grants31

  1. Role for Wnt/beta-catenin signaling in alveolar repair and fibrosis
    Cara J Gottardi; Fiscal Year: 2013
    ..By parsing the effects of Wnt/b-catenin signaling in both alveolar epithelial and fibroblast components, we will provide much needed insight into the instigating causes of fibrotic lung diseases. ..
  2. South Carolina IDeA Network of Biomedical Research Excellence
    LUCIA AMELIA PIRISI-CREEK; Fiscal Year: 2013
    ..We will intensify and focus our efforts to further build and support the pipeline for training, with particular attention to the recruitment and retention of minorities in biomedical science. ..
  3. Molecular mechanisms of hypoxia tolerance and susceptibility
    Gabriel G Haddad; Fiscal Year: 2013
    ..abstract_text> ..
  4. GENE THERAPY USING HEMATOPOIETIC STEM CELLS
    Donald B Kohn; Fiscal Year: 2013
    ..The Project and Core leaders have complementary expertise in the relevant areas of experimental hematology, gene therapy, immunology, and signal transduction and have a long-standing record of interactive collaborations. ..
  5. Mitochondrial Target for Radiation Mitigation
    Joel S Greenberger; Fiscal Year: 2013
    ..abstract_text> ..
  6. Mechanisms of beta-catenin signaling in alveolar epithelial cell differentiation
    Michael Kahn; Fiscal Year: 2013
    ....
  7. Developmental Exposure Alcohol Research Center
    Linda Patia Spear; Fiscal Year: 2013
    ..Thus, the DEARC will serve as a nexus of alcohol research in Central New York and as a beacon for national activities. ..
  8. ADAPTATIONS TO HYPOXIA
    Kurt R Stenmark; Fiscal Year: 2013
    ..abstract_text> ..
  9. Zinc deficiency in the alcoholic lung
    Pratibha C Joshi; Fiscal Year: 2013
    ....
  10. Novel Molecular Mechanisms Promote GPCR-Induced Bronchodilation in Asthma
    REYNOLD ALEXANDER PANETTIERI; Fiscal Year: 2013
    ..abstract_text> ..
  11. Mechanisms of Adaptation to Exercise in Health and COPD
    Peter D Wagner; Fiscal Year: 2013
    ....
  12. The mechanisms by which alcohol and HIV render the lung susceptible to injury
    DAVID MARSHALL GUIDOT; Fiscal Year: 2013
    ..This research project is designed to determine how alcohol and HIV-1 interact to make the lung susceptible to injury, and to develop effective treatments that can improve the health of these vulnerable individuals. ..
  13. Epigenic Regulation of Lung Progenitor Repair and Regeneration
    Edward E Morrisey; Fiscal Year: 2013
    ..Since small molecule modulators of miRNA and Hdac pathways exist, we believe that investigation into how these pathways regulate lung regeneration will have an important impact on the development of new therapies for lung disease..
  14. Molecular programming of AEC differentiation: role of forkhead factors
    Zea Borok; Fiscal Year: 2013
    ....
  15. DEVELOPMENT AND CONTROL OF PULMONARY ALVEOLAR STABILITY
    Samuel Hawgood; Fiscal Year: 2013
    ..abstract_text> ..
  16. Endothelial Injury and Repair: CardioPulmonary Vascular Biology COBRE
    SHARON IRENE SMITH ROUNDS; Fiscal Year: 2013
    ..abstract_text> ..
  17. Regulation of pulmonary fibrosis by the sonic hedgehog pathway
    William E Lawson; Fiscal Year: 2013
    ....
  18. Pathophysiology of Alveolar Epithelial Lung Injury
    Jacob I Sznajder; Fiscal Year: 2013
    ..The insights gained from the data generated from these studies will provide novel molecular targets for the development of new therapeutic strategies to treat patients with lung injury. ..
  19. Evolving Microenvironments in Airway Inflammation
    George H Caughey; Fiscal Year: 2013
    ..End of Abstract) ..
  20. Pacific Southwest RCE for Biodefense &Emerging Infectious Diseases Research
    Alan G Barbour; Fiscal Year: 2013
    ..abstract_text> ..
  21. Regulation of Pulmonary Fibrosis by CXCR3
    PAUL WESLEY NOBLE; Fiscal Year: 2013
    ..Understanding the roles of the CXCL10/CXCR3 axis in the pathobiology of lung injury and repair could lead to new therapies for progressive pulmonary fibrosis. ..