Ernst William Spannhake

Johns Hopkins University, Baltimore, Maryland, United States

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Publications (5)22.3 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: c-Met, the receptor tyrosine kinase whose natural ligand is hepatocyte growth factor (HGF), is known to have a key role in cell motility. We have previously shown that lysophosphatidic acid (LPA) induced a decrease in c-Met activation via serine phosphorylation of c-Met at cell-cell contacts. Here, we demonstrate that lipopolysaccharide (LPS) treatment of human bronchial epithelial cells induced internalization of c-Met via phosphorylation at its tyrosine residue 1003. In addition, it induced epithelial barrier dysfunction as evidenced by a decrease in transepithelial resistance (TER) in a time-dependent manner. Pretreatment with a c-Met inhibitor (PHA-665752) or inhibition of PKCα attenuated the LPS-mediated phosphorylation of c-Met and its internalization. LPS-induced c-Met tyrosine 1003 phosphorylation, activation of PKCα , and c-Met internalization were, however, reversed by pretreatment of cells with LPA which increased c-Met accumulation at cell-cell contacts. Inhibition of LPS-mediated c-Met tyrosine (Y1003) phosphorylation and internalization by prior treatment with PHA-665752, inhibition of PKCα, or over-expression of c-Met(Y1003A) mutant attenuated LPS-induced reduction of TER. Further, we found that c-Met accumulation at cell-cell contacts contributed to LPA-enhanced epithelial barrier integrity, since down-regulation of c-Met by specific siRNA attenuated LPA-increased TER. The data reveal a novel biological function of c-Met in the regulation of lung epithelial barrier integrity.
    AJP Lung Cellular and Molecular Physiology 04/2013; 305(1). DOI:10.1152/ajplung.00417.2012 · 4.04 Impact Factor
  • Andrew P Lane, Bahman Saatian, Xiao-Ying Yu, Ernst William Spannhake
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    ABSTRACT: Although the mechanisms underlying the initiation and maintenance of inflammation in chronic rhinosinusitis are poorly understood, the activation of memory T cells within the nasal mucosa is thought to play an important role. T-cell activation requires specialized antigen processing and presentation of antigen by immunocompetent cells in the context of cell surface immune molecules. The purpose of this study was to investigate the expression of such molecules by human sinonasal epithelial cells grown in culture at the air-liquid interface (ALI). Middle meatal epithelium was obtained from six patients undergoing endoscopic sinus surgery. Dissociated epithelial cells were grown to confluence in serum-free, defined medium and transferred to filter inserts for culture at the ALI. Cells were harvested at 2 and 21 days of growth at the ALI and processed for real-time polymerase chain reaction (PCR). The presence and relative abundance of constitutively expressed mRNA for human leukocyte antigen (HLA)-B, HLA-DR, B7 to 1, B7 to 2, B7-H2, B7-H3, and cathepsin D were assessed. After 2 days at the ALI, middle meatal epithelial cells demonstrated expression of genes for each of the antigen processing associated genes tested. The expression of HLA-B and HLA-DR increased significantly with cellular maturation at the ALI. Expression of HLA-DR and B7 to 1 increased with cytokine stimulation. Primary human epithelial cells obtained from the middle meatus express genes associated with antigen presentation function. The pattern of gene expression is modulated by cytokine stimulation and changes as the cells differentiate at the ALI. These findings suggest that mature middle meatal epithelial cells have the cellular machinery to interact with T cells and therefore may be direct participants in the modulation of T-cell activity in chronic sinusitis.
    The Laryngoscope 11/2004; 114(10):1827-32. DOI:10.1097/00005537-200410000-00028 · 2.03 Impact Factor
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    ABSTRACT: Lysophosphatidic acid (LPA), a potent bioactive lipid, elicits many of its biological actions via the specific G-protein-coupled receptors LPA1, LPA2, LPA3, and LPA4. Recently, we have shown that LPA-induced transactivation of platelet-derived growth factor receptor-beta is regulated by phospholipase D2 in human bronchial epithelial cells (HBEpCs) (Wang, L., Cummings, R. J., Zhao, Y., Kazlauskas, A., Sham, J., Morris, A., Brindley, D. N., Georas, S., and Natarajan, V. (2003) J. Biol. Chem. 278, 39931-39940). Here, we report that protein kinase Cdelta (PKCdelta) mediates LPA-induced NF-kappaB transcription and interleukin-8 (IL-8) secretion in HBEpCs. Treatment of HBEpCs with LPA increased both IL-8 gene and protein expression, which was coupled to Gi and G(12/13) proteins. LPA caused a marked activation of NF-kappaB in HBEpCs as determined by IkappaB phosphorylation and of NF-kappaB nuclear translocation and a strong induction of NF-kappaB promoter-mediated luciferase activity. Furthermore, LPA-activated PKCdelta and the LPA-mediated activation of NF-kappaB and IL-8 production were attenuated by overexpression of dominant-negative PKCdelta and rottlerin. Intratracheal administration of LPA in mice resulted in elevated levels of macrophage inflammatory protein-2, a murine homolog of IL-8, and an influx of neutrophils in the bronchoalveolar lavage fluid. These results demonstrate for the first time that LPA is a potent stimulator of IL-8 production in HBEpCs, which involves PKCdelta/NF-kappaB signaling pathways.
    Journal of Biological Chemistry 10/2004; 279(39):41085-94. DOI:10.1074/jbc.M404045200 · 4.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Lysophosphatidic acid (LPA), a potent bioactive lipid, elicits many of its biological actions via the specific G-protein-coupled receptors LPA1, LPA2, LPA3, and LPA4. Recently, we have shown that LPA-induced transactivation of platelet-derived growth factor receptor-β is regulated by phospholipase D2 in human bronchial epithelial cells (HBEpCs) (Wang, L., Cummings, R. J., Zhao, Y., Kazlauskas, A., Sham, J., Morris, A., Brindley, D. N., Georas, S., and Natarajan, V. (2003) J. Biol. Chem. 278, 39931-39940). Here, we report that protein kinase Cδ (PKCδ) mediates LPA-induced NF-κB transcription and interleukin-8 (IL-8) secretion in HBEpCs. Treatment of HBEpCs with LPA increased both IL-8 gene and protein expression, which was coupled to Gi and G12/13 proteins. LPA caused a marked activation of NF-κB in HBEpCs as determined by IκB phosphorylation and of NF-κB nuclear translocation and a strong induction of NF-κB promoter-mediated luciferase activity. Furthermore, LPA-activated PKCδ and the LPA-mediated activation of NF-κB and IL-8 production were attenuated by overexpression of dominant-negative PKCδ and rottlerin. Intratracheal administration of LPA in mice resulted in elevated levels of macrophage inflammatory protein-2, a murine homolog of IL-8, and an influx of neutrophils in the bronchoalveolar lavage fluid. These results demonstrate for the first time that LPA is a potent stimulator of IL-8 production in HBEpCs, which involves PKCδ/NF-κB signaling pathways.
    Journal of Biological Chemistry 09/2004; 279(39):41085-41094. · 4.60 Impact Factor
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    ABSTRACT: Of the several factors believed to exacerbate asthmatic symptoms, air pollution and viral infections are considered to be particularly important. Although evidence indicates that each of these respiratory insults individually can increase asthma severity in susceptible individuals, we know little about the extent to which exposure to environmental oxidant pollutants can influence the course of respiratory viral infection and its associated inflammation. To investigate the interaction of these two stimuli within their common epithelial cell targets in the upper and lower respiratory tracks, we infected primary human nasal epithelial cells and cells of the BEAS-2B line grown at the air-liquid interface with human rhinovirus type 16 (RV16) and exposed them to NO2 (2.0 ppm) or O3 (0.2 ppm) for 3 hr. Independently, RV16, NO2, and O3 rapidly increased release of the inflammatory cytokine interleukin-8 through oxidant-dependent mechanisms. The combined effect of RV16 and oxidant ranged from 42% to 250% greater than additive for NO2 and from 41% to 67% for O3. We abrogated these effects by treating the cells with the antioxidant N-acetylcysteine. Surface expression of intercellular adhesion molecule 1 (ICAM-1) underwent additive enhancement in response to combined stimulation. These data indicate that oxidant pollutants can amplify the generation of proinflammatory cytokines by RV16-infected cells and suggest that virus-induced inflammation in upper and lower airways may be exacerbated by concurrent exposure to ambient levels of oxidants commonly encountered the indoor and outdoor environments.
    Environmental Health Perspectives 08/2002; 110(7):665-70. DOI:10.1289/ehp.02110665 · 7.03 Impact Factor

Publication Stats

154 Citations
22.30 Total Impact Points

Institutions

  • 2004–2013
    • Johns Hopkins University
      • Department of Environmental Health Sciences
      Baltimore, Maryland, United States
    • Showa University
      • Institute of Molecular Oncology
      Shinagawa, Tōkyō, Japan
  • 2002–2004
    • Johns Hopkins Bloomberg School of Public Health
      • Department of Environmental Health Sciences
      Baltimore, MD, United States