title: Prostaglandin E2 released from activated microglia enhances astrocyte proliferation in vitro.
abstract: Microglial activation has been implicated in many astrogliosis-related pathological conditions including astroglioma; however, the detailed mechanism is not clear. In this study, we used primary enriched microglia and astrocyte cultures to determine the role of microglial prostaglandin E(2) (PGE(2)) in the proliferation of astrocytes. The proliferation of astrocytes was measured by BrdU incorporation. The level of PGE(2) was measured by ELISA method. Pharmacological inhibition or genetic ablation of COX-2 in microglia were also applied in this study. We found that proliferation of astrocytes increased following lipopolysaccharide (LPS) treatment in the presence of microglia. Furthermore, increased proliferation of astrocytes was observed in the presence of conditioned media from LPS-treated microglia. The potential involvement of microglial PGE(2) in enhanced astrocyte proliferation was suggested by the findings that PGE(2) production and COX-2 expression in microglia were increased by LPS treatment. In addition, activated microglia-induced increases in astrocyte proliferation were blocked by the PGE(2) antagonist AH6809, COX-2 selective inhibitor DuP-697 or by genetic knockout of microglial COX-2. These findings were further supported by the finding that addition of PGE(2) to the media significantly induced astrocyte proliferation. These results indicate that microglial PGE(2) plays an important role in astrocyte proliferation, identifying PGE(2) as a key neuroinflammatory molecule that triggers the pathological response related to uncontrollable astrocyte proliferation. These findings are important in elucidating the role of activated microglia and PGE(2) in astrocyte proliferation and in suggesting a potential avenue in the use of anti-inflammatory agents for the therapy of astroglioma.
authors.affiliation: Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Hu
authors.forename: Li
authors.initials: L
authors.lastname: Qian
authors.forename: Belinda
authors.initials: B
authors.lastname: Wilson
authors.forename: Christopher
authors.initials: C
authors.lastname: Lee
authors.forename: Patrick
authors.initials: P
authors.lastname: Flood
authors.forename: Robert
authors.initials: R
authors.lastname: Langenbach
authors.forename: Jau-Shyong
authors.initials: JS
authors.lastname: Hong
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D051546:Cyclooxygenase 2 / Q000187:drug effects / Q000235:genetics*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000008:administration & dosage / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D013876:Thiophenes / Q000494:pharmacology; D044004:Xanthones / Q000494:pharmacology
chemical_list: D016861:Cyclooxygenase Inhibitors; D008070:Lipopolysaccharides; D011448:Prostaglandin Antagonists; D013876:Thiophenes; D044004:Xanthones; C053876:6-isopropoxy-9-oxoxanthene-2-carboxylic acid; C064874:DuP 697; D051546:Cyclooxygenase 2; D015232:Dinoprostone