title: Neutralization of chemokine-like factor 1, a novel C-C chemokine, protects against focal cerebral ischemia by inhibiting neutrophil infiltration via MAPK pathways in rats.
abstract: BACKGROUND
  Inflammation plays a key role in the pathophysiology of ischemic stroke. Some proinflammatory mediators, such as cytokines and chemokines, are produced in stroke. Chemokine-like factor 1 (CKLF1), as a novel C-C chemokine, displays chemotactic activities in a wide spectrum of leukocytes and plays an important role in brain development. In previous studies, we have found that the expression of CKLF1 increased in rats after focal cerebral ischemia and treatment with the CKLF1 antagonist C19 peptide decreased the infarct size and water content. However, the role of CKLF1 in stroke is still unclear. The objective of the present study was to ascertain the possible roles and mechanism of CKLF1 in ischemic brain injury by applying anti-CKLF1 antibody.
  
  
  METHODS
  Male Sprague-Dawley rats were subjected to one-hour middle cerebral artery occlusion. Antibody to CKLF1 was applied to the right cerebral ventricle immediately after reperfusion; infarct volume and neurological score were measured at 24 and 72 hours after cerebral ischemia. RT-PCR, Western blotting and ELISA were utilized to characterize the expression of adhesion molecules, inflammatory factors and MAPK signal pathways. Immunohistochemical staining and myeloperoxidase activity was used to determine the extent of neutrophil infiltration.
  
  
  RESULTS
  Treatment with anti-CKLF1 antibody significantly decreased neurological score and infarct volume in a dose-dependent manner at 24 and 72 hours after cerebral ischemia. Administration with anti-CKLF1 antibody lowered the level of inflammatory factors TNF-α, IL-1β, MIP-2 and IL-8, the expression of adhesion molecules ICAM-1 and VCAM-1 in a dose-dependent manner. The results of immunohistochemical staining and detection of MPO activity indicated that anti-CKLF1 antibody inhibited neutrophil infiltration. Further studies suggested MAPK pathways associated with neutrophil infiltration in cerebral ischemia.
  
  
  CONCLUSIONS
  Selective inhibition of CKLF1 activity significantly protects against ischemia/reperfusion injury by decreasing production of inflammatory mediators and expression of adhesion molecules, thereby reducing neutrophils recruitment to the ischemic area, possibly via inhibiting MAPK pathways. Therefore, CKLF1 may be a novel target for the treatment of stroke.
authors.forename: Ling Lei
authors.initials: LL
authors.lastname: Kong
authors.forename: Zhi Yuan
authors.initials: ZY
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Han
authors.forename: Xiao Mei
authors.initials: XM
authors.lastname: Zhuang
authors.forename: Zhen Zhen
authors.initials: ZZ
authors.lastname: Wang
authors.affiliation: The Key Lab of Drug Metabolism and Pharmacokinetics, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Haidian District, Beijing 100850, China. amms_hli@126.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Nai Hong
authors.initials: NH
authors.lastname: Chen
mesh_terms: D000818:Animals; D000906:Antibodies / Q000627:therapeutic use*; D020520:Brain Infarction / Q000209:etiology / Q000517:prevention & control; D018925:Chemokines / Q000037:antagonists & inhibitors / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism; D062792:MARVEL Domain-Containing Proteins / Q000037:antagonists & inhibitors / Q000276:immunology*; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009460:Neurologic Examination; D020556:Neutrophil Infiltration / Q000187:drug effects* / Q000502:physiology; D010455:Peptides / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D018709:Statistics, Nonparametric; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism
chemical_list: D000906:Antibodies; C560037:C19 peptide; D018925:Chemokines; C486623:Cklf protein, rat; D016207:Cytokines; D062792:MARVEL Domain-Containing Proteins; D010455:Peptides; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D020929:Mitogen-Activated Protein Kinase Kinases