title: TNF-α and IL-1β-activated human mesenchymal stromal cells increase airway epithelial wound healing in vitro via activation of the epidermal growth factor receptor.
abstract: BACKGROUND
  Mesenchymal stromal cells (MSCs) are investigated for their potential to reduce inflammation and to repair damaged tissue. Inflammation and tissue damage are hallmarks of chronic obstructive pulmonary disease (COPD) and MSC infusion is a promising new treatment for COPD. Inflammatory mediators attract MSCs to sites of inflammation and affect their immune-modulatory properties, but little is known about their effect on regenerative properties of MSCs. This study investigates the effect of the pro-inflammatory cytokines TNF-α and IL-1β on the regenerative potential of MSCs, using an in vitro wound healing model of airway epithelial cells.
  
  
  METHODS
  Standardized circular wounds were created by scraping cultures of the airway epithelial cell line NCI-H292 and primary bronchial epithelial cells cultured at the air-liquid interface (ALI-PBEC), and subsequently incubated with MSC conditioned medium (MSC-CM) that was generated in presence or absence of TNF-α/IL-1β. Remaining wound size was measured up to 72 h. Phosphorylation of ERK1/2 by MSC-CM was assessed using Western blot. Inhibitors for EGFR and c-Met signaling were used to investigate the contribution of these receptors to wound closure and to ERK1/2 phosphorylation. Transactivation of EGFR by MSC-CM was investigated using a TACE inhibitor, and RT-PCR was used to quantify mRNA expression of several growth factors in MSCs and NCI-H292.
  
  
  RESULTS
  Stimulation of MSCs with the pro-inflammatory cytokines TNF-α and IL-1β increased the mRNA expression of various growth factors by MCSs and enhanced the regenerative potential of MSCs in an in vitro model of airway epithelial injury using NCI-H292 airway epithelial cells. Conditioned medium from cytokine stimulated MSCs induced ERK1/2 phosphorylation in NCI-H292, predominantly via EGFR; it induced ADAM-mediated transactivation of EGFR, and it induced airway epithelial expression of several EGFR ligands. The contribution of activation of c-Met via HGF to increased repair could not be confirmed by inhibitor experiments.
  
  
  CONCLUSIONS
  Our data imply that at sites of tissue damage, when inflammatory mediators are present, for example in lungs of COPD patients, MSCs become more potent inducers of repair, in addition to their well-known immune-modulatory properties.
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. w.broekman@lumc.nl.
authors.forename: Winifred
authors.initials: W
authors.lastname: Broekman
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. g.d.amatngalim@lumc.nl.
authors.forename: Gimano D
authors.initials: GD
authors.lastname: Amatngalim
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. yvonne.de.mooij@hotmail.com.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: de Mooij-Eijk
authors.affiliation: Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands. oostendorpjaap@gmail.com.
authors.forename: Jaap
authors.initials: J
authors.lastname: Oostendorp
authors.affiliation: Department of Immunohaematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands. h.roelofs@lumc.nl.
authors.forename: Helene
authors.initials: H
authors.lastname: Roelofs
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. c.taube@lumc.nl.
authors.forename: Christian
authors.initials: C
authors.lastname: Taube
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. j.stolk@lumc.nl.
authors.forename: Jan
authors.initials: J
authors.lastname: Stolk
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands. p.s.hiemstra@lumc.nl.
authors.forename: Pieter S
authors.initials: PS
authors.lastname: Hiemstra
mesh_terms: D002450:Cell Communication / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D004847:Epithelial Cells; D066246:ErbB Receptors / Q000276:immunology*; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000276:immunology*; D020545:Respiratory Mucosa / Q000276:immunology* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*; D014945:Wound Healing / Q000276:immunology*
chemical_list: D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha; C512478:EGFR protein, human; D066246:ErbB Receptors