title: Leukocyte transmigration into tissue-engineered constructs is influenced by endothelial cells through Toll-like receptor signaling.
abstract: BACKGROUND
  Inflammation plays a crucial role in tissue regeneration, wound healing, and the success of tissue-engineered constructs. The aim of this study was to investigate the influence of human umbilical vein endothelial cells (ECs) on leukocyte transmigration when co-cultured with primary human bone marrow-derived multipotent stromal cells (MSCs).
  
  
  METHODS
  MSCs with and without ECs were cultured in poly (L-lactide-co-1, 5-dioxepan-2-one) (poly (LLA-co-DXO)) scaffolds for 1 week in vitro in a bioreactor system, after which they were implanted subcutaneously in non-obese diabetic/severe combined immunodeficient mice. After 1 and 3 weeks, scaffolds were retrieved, and the mRNA expression of interleukin 1-beta (IL-1β), IL-6, IL-10, hypoxia-inducible factor 1-alpha (HIF-1α), HIF-1β, and mammalian target of rapamycin was examined by real-time reverse transcription-polymerase chain reaction. Furthermore, immunofluorescent staining was performed for IL-1β, IL-6, neutrophils, and CD11b. In addition, Western blotting was done for IL-1β and IL-6. Leukocyte transmigration genes and genes in Toll-like receptor pathways, expressed by MSCs cultured in vitro with or without ECs, were further investigated with a microarray dataset.
  
  
  RESULTS
  In vitro, genes involved in leukocyte transmigration and Toll-like receptor pathways were clearly influenced by the addition of ECs. Platelet/endothelial cell adhesion molecule-1 (PECAM-1) and cadherin-5 (CDH5), both genes involved in leukocyte transmigration, were expressed significantly higher in the MSC/EC group.
  
  
  CONCLUSIONS
  The recruitment of leukocytes into tissue-engineered constructs with MSCs is strongly influenced by the addition of ECs via activation of leukocyte transmigration and Toll-like receptor pathways.
authors.forename: Sushma
authors.initials: S
authors.lastname: Bartaula-Brevik
authors.forename: Torbjorn O
authors.initials: TO
authors.lastname: Pedersen
authors.forename: Anna L
authors.initials: AL
authors.lastname: Blois
authors.forename: Panagiota
authors.initials: P
authors.lastname: Papadakou
authors.forename: Anna
authors.initials: A
authors.lastname: Finne-Wistrand
authors.forename: Ying
authors.initials: Y
authors.lastname: Xue
authors.forename: Anne Isine
authors.initials: AI
authors.lastname: Bolstad
authors.forename: Kamal
authors.initials: K
authors.lastname: Mustafa
mesh_terms: D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D007378:Interleukins / Q000235:genetics / Q000378:metabolism; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D023822:Tissue Engineering; D054457:Tissue Scaffolds; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism*; D057705:Transendothelial and Transepithelial Migration
chemical_list: D015820:Cadherins; D017077:Culture Media, Conditioned; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007378:Interleukins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D012333:RNA, Messenger; D051193:Toll-Like Receptors; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator