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Expression of sphingosine kinase 1 in amoeboid microglial cells in the corpus callosum of postnatal rats.

Lin H, Baby N, Lu J, Kaur C, Zhang C, Xu J, Ling EA, Dheen ST - J Neuroinflammation (2011)

Bottom Line: 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.We conclude that SphK1 expression in AMC may be linked to regulation of proinflammatory cytokines via an NFκB signaling pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomy, Second Military Medical University, 800 Xiangyin Road, Shanghai, 200433, PR China.

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.

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Quantitative analysis of number and intensity of SphK1 positive AMC. Significantly increased numbers of SphK1-positive AMC (co-expressing OX-42) are evident in 1 h after hypoxia (A). The intensity of SphK1 immunofluorescence is increased significantly at 15 min and 1 h compared with that 6 h after hypoxia and that of control (B). The data are presented as mean ± S.E. Control vs Hypoxia, * P < 0.05, ** P < 0.01
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Figure 6: Quantitative analysis of number and intensity of SphK1 positive AMC. Significantly increased numbers of SphK1-positive AMC (co-expressing OX-42) are evident in 1 h after hypoxia (A). The intensity of SphK1 immunofluorescence is increased significantly at 15 min and 1 h compared with that 6 h after hypoxia and that of control (B). The data are presented as mean ± S.E. Control vs Hypoxia, * P < 0.05, ** P < 0.01

Mentions: In rats subjected to hypoxic exposure, SphK1 immunoexpression in AMC was drastically increased (Figure 5A-D, Figure 6A). Virtually all OX-42-positive AMC exhibited more intense SphK1 immunofluorescence 1 h after hypoxia, compared with that in control rats (Figure 5Ca-c, Figure 6A). At 6 h after hypoxia, SphK1 immunofluorescence in AMC appeared to be diminished, although OX-42 immunofluorescence in AMC remained intense and the cells were hypertrophic (Figure 5Da-c).


Expression of sphingosine kinase 1 in amoeboid microglial cells in the corpus callosum of postnatal rats.

Lin H, Baby N, Lu J, Kaur C, Zhang C, Xu J, Ling EA, Dheen ST - J Neuroinflammation (2011)

Quantitative analysis of number and intensity of SphK1 positive AMC. Significantly increased numbers of SphK1-positive AMC (co-expressing OX-42) are evident in 1 h after hypoxia (A). The intensity of SphK1 immunofluorescence is increased significantly at 15 min and 1 h compared with that 6 h after hypoxia and that of control (B). The data are presented as mean ± S.E. Control vs Hypoxia, * P < 0.05, ** P < 0.01
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3050721&req=5

Figure 6: Quantitative analysis of number and intensity of SphK1 positive AMC. Significantly increased numbers of SphK1-positive AMC (co-expressing OX-42) are evident in 1 h after hypoxia (A). The intensity of SphK1 immunofluorescence is increased significantly at 15 min and 1 h compared with that 6 h after hypoxia and that of control (B). The data are presented as mean ± S.E. Control vs Hypoxia, * P < 0.05, ** P < 0.01
Mentions: In rats subjected to hypoxic exposure, SphK1 immunoexpression in AMC was drastically increased (Figure 5A-D, Figure 6A). Virtually all OX-42-positive AMC exhibited more intense SphK1 immunofluorescence 1 h after hypoxia, compared with that in control rats (Figure 5Ca-c, Figure 6A). At 6 h after hypoxia, SphK1 immunofluorescence in AMC appeared to be diminished, although OX-42 immunofluorescence in AMC remained intense and the cells were hypertrophic (Figure 5Da-c).

Bottom Line: 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.We conclude that SphK1 expression in AMC may be linked to regulation of proinflammatory cytokines via an NFκB signaling pathway.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomy, Second Military Medical University, 800 Xiangyin Road, Shanghai, 200433, PR China.

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.

Show MeSH
Related in: MedlinePlus