Expression of cyclooxygenase-2 and microsomal prostaglandin-E synthase in amoeboid microglial cells in the developing brain and effects of cyclooxygenase-2 neutralization on BV-2 microglial cells.
Microglia express cyclooxygenase-2 (COX-2) and microsomal prostaglandin-E synthase (mPGES-1) but their localization in the amoeboid microglial cells (AMC), considered to be the nascent brain macrophages, in the developing brain has remained unexplored; furthermore, their interrelation and regulation have also remained to be fully elucidated. We show here that AMC in postnatal rat brain constitutively expressed COX-2 and mPGES-1 whose immunoexpression was upregulated in rats given lipopolysaccharide (LPS) injections. Reverse transcriptase-polymerase chain reaction and Western blot analysis of the callosal tissue rich in AMC revealed that COX-2 and mPGES-1 mRNA and protein expression was augmented following LPS injections. BV-2 cells also exhibited COX-2 and mPGES-1 expression which was enhanced by LPS. However, in cells treated with LPS coupled with COX-2 neutralization, the mRNA expression levels of COX-2, mPGES-1, tumor necrosis factor-alpha, interleukin-1beta and inducible nitric oxide synthase were significantly suppressed; production of prostaglandin E(2) and reactive oxygen species also decreased. Western blot analysis confirmed the changes of protein levels of the above mediators. Remarkably, COX-2 neutralization concomitantly suppressed the protein expression levels of nuclear factor-kappa B (NF-kappaB), phos-NF-kappaB and phos-IkappaB-alpha as well as translocation of NF-kappaB as determined by flow cytometry. In conclusion, AMC in the developing brain expressed COX-2 and mPGES-1 notably when stimulated by LPS. It is suggested that this may be involved in local inflammation during development. Our results have further shown that COX-2 neutralization may be effective in suppressing production of inflammatory mediators and hence its potential use in alleviating neuroinflammation.
Li
Ping
P
Department of Histology and Embryology, Faculty of Basic Medical Sciences, Kunming Medical College, China.
Kaur
Charanjit
C
Lu
Jia
J
Sivakumar
V
V
Dheen
S Thameem
ST
Ling
Eng-Ang
EA
D000818:Animals; D000831:Animals, Newborn; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D051546:Cyclooxygenase 2 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism; D004660:Encephalitis / Q000188:drug therapy / Q000201:enzymology* / Q000503:physiopathology; D005911:Gliosis / Q000188:drug therapy / Q000201:enzymology* / Q000503:physiopathology; D018836:Inflammation Mediators / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D000071876:Prostaglandin-E Synthases; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011458:Prostaglandins E / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
D052246:Cyclooxygenase 2 Inhibitors; D016207:Cytokines; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D016328:NF-kappa B; D011458:Prostaglandins E; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D052247:Nitric Oxide Synthase Type II; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D000071876:Prostaglandin-E Synthases; C497818:Ptges protein, rat