title: Alternatively-spliced extra domain A of fibronectin promotes acute inflammation and brain injury after cerebral ischemia in mice.
abstract: OBJECTIVE
  The fibronectin isoform containing the alternatively spliced extra domain A (EDA(+)-FN) is normally absent from the circulation, but plasma levels of EDA(+)-FN can become markedly elevated in several human pathological conditions associated with inflammation including ischemic stroke. It remains unknown whether EDA(+)-FN contributes to stroke pathogenesis or is simply an associative marker. Several in vitro studies suggest that EDA(+)-FN can activate Toll-like receptor 4, an innate immune receptor that triggers proinflammatory responses. We undertook a genetic approach in mice to investigate the ability of EDA(+)-FN to mediate inflammatory brain damage in a focal cerebral ischemia/reperfusion injury model.
  
  
  METHODS
  We used genetically modified EDA(+/+) mice, which constitutively express EDA(+)-FN. Extent of injury, neurological outcome, and inflammatory mechanisms were assessed after 1-hour cerebral ischemia/23-hour reperfusion injury and compared with wild-type mice.
  
  
  RESULTS
  We found that EDA(+/+) mice developed significantly larger infarcts and severe neurological deficits that were associated with significant increased neutrophil and macrophage infiltration as quantitated by immunohistochemistry. Additionally, we found upregulation of nuclear factor-κB, cyclo-oxygenase-2, and inflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the EDA(+/+) mice compared with wild-type mice. Interestingly, increased brain injury and neurological deficits were largely abrogated in EDA(+/+) mice by treatment with a specific Toll-like receptor 4 inhibitor.
  
  
  CONCLUSIONS
  These findings provide the first evidence that EDA(+)-FN promotes inflammatory brain injury after ischemic stroke and suggest that the elevated levels of plasma EDA(+)-FN observed in chronic inflammatory conditions could worsen injury and outcome in patients after acute stroke.
authors.affiliation: University of Iowa, Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA 52242, USA.
authors.forename: Mohammad Moshahid
authors.initials: MM
authors.lastname: Khan
authors.forename: Chintan
authors.initials: C
authors.lastname: Gandhi
authors.forename: Neelam
authors.initials: N
authors.lastname: Chauhan
authors.forename: Jeff W
authors.initials: JW
authors.lastname: Stevens
authors.forename: David G
authors.initials: DG
authors.lastname: Motto
authors.forename: Steven R
authors.initials: SR
authors.lastname: Lentz
authors.forename: Anil K
authors.initials: AK
authors.lastname: Chauhan
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001930:Brain Injuries / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D002545:Brain Ischemia / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D051546:Cyclooxygenase 2 / Q000502:physiology; D016207:Cytokines / Q000502:physiology; D004660:Encephalitis / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D005353:Fibronectins / Q000097:blood / Q000235:genetics* / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D016328:NF-kappa B / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000235:genetics*; D013997:Time Factors; D051197:Toll-Like Receptor 4 / Q000502:physiology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D016207:Cytokines; D005353:Fibronectins; D016328:NF-kappa B; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C572454:extra domain A fibronectin, mouse; D051546:Cyclooxygenase 2