title: Expression of sphingosine kinase 1 in amoeboid microglial cells in the corpus callosum of postnatal rats.
abstract: Sphingosine kinase 1 (SphK1), a key enzyme responsible for phosphorylating sphingosine into sphingosine-1-phosphate (S1P) has been shown to be expressed in monocytes and monocyte-derived peripheral macrophages. This study demonstrates SphK1 immunoexpression in amoeboid microglial cells (AMC), a nascent monocyte-derived brain macrophage in the corpus callosum of developing rat brain. SphK1 immunofluorescence expression, which appeared to be weak in AMC in normal brain, was markedly induced by lipopolysaccharide (LPS) or hypoxia treatment. Western blot analysis also showed increased expression level of SphK1 in the corpus callosum rich in AMC after LPS treatment. Detection of SphK1 mRNA and its upregulation after LPS treatment was confirmed in primary culture AMC by RT-PCR. Administration of N, N-dimethylsphingosine (DMS), a specific inhibitor of SphK1, effectively reduced upregulated SphK1 immunoexpression in AMC both in vivo and in vitro. This was corroborated by western blot which showed a decrease in SphK1 protein level of callosal tissue with DMS pretreatment. Remarkably, LPS-induced upregulation of the transcription factor NFκB was suppressed by DMS. We conclude that SphK1 expression in AMC may be linked to regulation of proinflammatory cytokines via an NFκB signaling pathway.
authors.affiliation: Department of Anatomy, Second Military Medical University, 800 Xiangyin Road, Shanghai, 200433, PR China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Lin
authors.forename: Nimmi
authors.initials: N
authors.lastname: Baby
authors.forename: Jia
authors.initials: J
authors.lastname: Lu
authors.forename: Charanjit
authors.initials: C
authors.lastname: Kaur
authors.forename: Chuansen
authors.initials: C
authors.lastname: Zhang
authors.forename: Jiajun
authors.initials: J
authors.lastname: Xu
authors.forename: Eng-Ang
authors.initials: EA
authors.lastname: Ling
authors.forename: S Thameem
authors.initials: ST
authors.lastname: Dheen
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000033:anatomy & histology* / Q000378:metabolism*; D039481:CD11b Antigen / Q000378:metabolism; D002478:Cells, Cultured; D003337:Corpus Callosum / Q000166:cytology* / Q000254:growth & development; D006801:Humans; D000860:Hypoxia; D053583:Interleukin-1beta / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D016328:NF-kappa B / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D000099157:Sphingosine Kinase
chemical_list: D039481:CD11b Antigen; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D016328:NF-kappa B; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D000099157:Sphingosine Kinase