title: Early activation of pro-fibrotic WNT5A in sepsis-induced acute lung injury.
abstract: BACKGROUND
  The mechanisms of lung repair and fibrosis in the acute respiratory distress syndrome (ARDS) are poorly known. Since the role of WNT/β-catenin signaling appears to be central to lung healing and fibrosis, we hypothesized that this pathway is activated very early in the lungs after sepsis.
  
  
  METHODS
  We tested our hypothesis using a three-step experimental design: (1) in vitro lung cell injury model with human bronchial epithelial BEAS-2B and lung fibroblasts (MRC-5) cells exposed to endotoxin for 18 hours; (2) an animal model of sepsis-induced ARDS induced by cecal ligation and perforation, and (3) lung biopsies from patients who died within the first 24 hours of septic ARDS. We examined changes in protein levels of target genes involved in the Wnt pathway, including WNT5A, non-phospho (Ser33/37/Thr41) β-catenin, matrix metalloproteinase-7 (MMP7), cyclin D1, and vascular endothelial growth factor (VEGF) by Western blotting and immunohistochemistry. Finally, we validated the main gene targets of this pathway in experimental animals and human lungs.
  
  
  RESULTS
  Protein levels of WNT5A, non-phospho (Ser33/37/Thr41) β-catenin, total β-catenin, MMP7, cyclin D1, and VEGF increased after endotoxin stimulation in BEAS-2B and MRC-5 cells. Lungs from septic animals and from septic humans demonstrated acute lung inflammation, collagen deposition, and marked increase of WNT5A and MMP7 protein levels.
  
  
  CONCLUSIONS
  Our findings suggest that the WNT/β-catenin signaling pathway is activated very early in sepsis-induced ARDS and could play an important role in lung repair and fibrosis. Modulation of this pathway might represent a potential target for treatment for septic and ARDS patients.
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. jesus.villar54@gmail.com.|Multidisciplinary Organ Dysfunction Evaluation Research Network, Research Unit, Hospital Universitario Dr. Negrin, Las Palmas de Gran Canaria, Spain. jesus.villar54@gmail.com.|Keenan Research Center for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada. jesus.villar54@gmail.com.
authors.forename: Jesús
authors.initials: J
authors.lastname: Villar
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. nuriaecb@gmail.com.|Multidisciplinary Organ Dysfunction Evaluation Research Network, Research Unit, Hospital Universitario Dr. Negrin, Las Palmas de Gran Canaria, Spain. nuriaecb@gmail.com.
authors.forename: Nuria E
authors.initials: NE
authors.lastname: Cabrera-Benítez
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. shefloanse@hotmail.com.|Multidisciplinary Organ Dysfunction Evaluation Research Network, Research Unit, Hospital Universitario Dr. Negrin, Las Palmas de Gran Canaria, Spain. shefloanse@hotmail.com.
authors.forename: Angela
authors.initials: A
authors.lastname: Ramos-Nuez
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. cflores@ull.edu.es.|Research Unit, Hospital Universitario NS de Candelaria, Santa Cruz de Tenerife, Spain. cflores@ull.edu.es.
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores
authors.affiliation: Department of Anatomy, Pathology & Histology, Medical School University of La Laguna and Hospital Universitario de Canarias, La Laguna, Tenerife, Spain. soniagaher76@gmail.com.
authors.forename: Sonia
authors.initials: S
authors.lastname: García-Hernández
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. fvallapa@gmail.com.|Department of Anatomy, Pathology & Histology, Medical School University of La Laguna and Hospital Universitario de Canarias, La Laguna, Tenerife, Spain. fvallapa@gmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: Valladares
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. JLopezA@tauli.cat.|Critical Care Center, Corporació Sanitaria Parc Taulí, Sabadell, Barcelona, Spain. JLopezA@tauli.cat.
authors.forename: Josefina
authors.initials: J
authors.lastname: López-Aguilar
authors.affiliation: CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain. lblanch@tauli.cat.|Critical Care Center, Corporació Sanitaria Parc Taulí, Sabadell, Barcelona, Spain. lblanch@tauli.cat.
authors.forename: Lluís
authors.initials: L
authors.lastname: Blanch
authors.affiliation: Keenan Research Center for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada. lblanch@tauli.cat.|Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada. lblanch@tauli.cat.
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Slutsky
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002478:Cells, Cultured; D005355:Fibrosis / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000378:metabolism* / Q000473:pathology; D018805:Sepsis / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D051153:Wnt Proteins / Q000378:metabolism*; D000071818:Wnt-5a Protein
chemical_list: D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C491837:Wnt5a protein, rat