title: Different actions of endothelin-1 on chemokine production in rat cultured astrocytes: reduction of CX3CL1/fractalkine and an increase in CCL2/MCP-1 and CXCL1/CINC-1.
abstract: BACKGROUND
  Chemokines are involved in many pathological responses of the brain. Astrocytes produce various chemokines in brain disorders, but little is known about the factors that regulate astrocytic chemokine production. Endothelins (ETs) have been shown to regulate astrocytic functions through ETB receptors. In this study, the effects of ETs on chemokine production were examined in rat cerebral cultured astrocytes.
  
  
  METHODS
  Astrocytes were prepared from the cerebra of one- to two-day-old Wistar rats and cultured in serum-containing medium. After serum-starvation for 48 hours, astrocytes were treated with ETs. Total RNA was extracted using an acid-phenol method and expression of chemokine mRNAs was determined by quantitative RT-PCR. The release of chemokines was measured by ELISA.
  
  
  RESULTS
  Treatment of cultured astrocytes with ET-1 and Ala(1,3,11,15)-ET-1, an ET(B) agonist, increased mRNA levels of CCL2/MCP1 and CXCL1/CINC-1. In contrast, CX3CL1/fractalkine mRNA expression decreased in the presence of ET-1 and Ala(1,3,11,15)-ET-1. The effect of ET-1 on chemokine mRNA expression was inhibited by BQ788, an ET(B) antagonist. ET-1 increased CCL2 and CXCL1 release from cultured astrocytes, but decreased that of CX3CL1. The increase in CCL2 and CXCL1 expression by ET-1 was inhibited by actinomycin D, pyrrolidine dithiocarbamate, SN50, mithramycin, SB203580 and SP600125. The decrease in CX3CL1 expression by ET-1 was inhibited by cycloheximide, Ca(2+) chelation and staurosporine.
  
  
  CONCLUSIONS
  These findings suggest that ETs are one of the factors regulating astrocytic chemokine production. Astrocyte-derived chemokines are involved in pathophysiological responses of neurons and microglia. Therefore, the ET-induced alterations of astrocytic chemokine production are of pathophysiological significance in damaged brains.
authors.affiliation: Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-Kita, Tonda-bayashi, Osaka, 584-8540, Japan. koyamay@osaka-ohtani.ac.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Koyama
authors.forename: Mao
authors.initials: M
authors.lastname: Kotani
authors.forename: Tadateru
authors.initials: T
authors.lastname: Sawamura
authors.forename: Miho
authors.initials: M
authors.lastname: Kuribayashi
authors.forename: Rika
authors.initials: R
authors.lastname: Konishi
authors.forename: Shotaro
authors.initials: S
authors.lastname: Michinaga
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism*; D054428:Chemokine CX3CL1 / Q000378:metabolism*; D054360:Chemokine CXCL1 / Q000378:metabolism*; D018925:Chemokines / Q000096:biosynthesis*; D019332:Endothelin-1 / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D018628:Gene Dosage; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D044023:Receptor, Endothelin B / Q000819:agonists / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; D054428:Chemokine CX3CL1; D054360:Chemokine CXCL1; D018925:Chemokines; C513297:Cxcl1 protein, rat; D019332:Endothelin-1; D012333:RNA, Messenger; D044023:Receptor, Endothelin B