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Anti-inflammatory effects of α-galactosylceramide analogs in activated microglia: involvement of the p38 MAPK signaling pathway.

Jeong YH, Kim Y, Song H, Chung YS, Park SB, Kim HS - PLoS ONE (2014)

Bottom Line: Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia.After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis.Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine and Global Top5 Research Program, Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, Republic of Korea.

ABSTRACT
Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1β, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.

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Inhibitory effect of α-GalCer analogs on NO/ROS/TNF-α production in LPS-stimulated microglial cells.a
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pone-0087030-g005: Inhibitory effect of α-GalCer analogs on NO/ROS/TNF-α production in LPS-stimulated microglial cells.a

Mentions: To investigate the anti-inflammatory effects of systematically designed α-GalCer analogs in microglial activation, BV2 cells were treated with compounds 1 h prior to stimulation with LPS, and the inhibitory effects of each α-GalCer analog on LPS-induced production of NO, ROS, and TNF-α were examined. As shown in Figure 5, we measured the percent inhibition of NO, ROS, and TNF-α production upon treatment with 25 α-GalCer analogs at 5 µM concentration. It is worth mentioning that known α-GalCer that are known to be bioactive in iNKT cells showed no or marginal inhibitory effects on LPS-stimulated microglia. For example, KRN7000, a representative α-GalCer, showed an inhibitory effect only on ROS production (24.4% inhibition) but no effect on the production of NO (3.9% inhibition) or TNF-α (1.5% inhibition). In the case of OCH, a known immunomodulatory α-GalCer in iNKT cells, we observed increased production of NO (15.1%) and only slight inhibitory effects on the production of ROS (12.5% inhibition) and TNF-α (13.6% inhibition). When we tested our TH2-selective α-GalCer analog 1c[25], there were marginal inhibitory activities in LPS-induced microglial cells.


Anti-inflammatory effects of α-galactosylceramide analogs in activated microglia: involvement of the p38 MAPK signaling pathway.

Jeong YH, Kim Y, Song H, Chung YS, Park SB, Kim HS - PLoS ONE (2014)

Inhibitory effect of α-GalCer analogs on NO/ROS/TNF-α production in LPS-stimulated microglial cells.a
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921125&req=5

pone-0087030-g005: Inhibitory effect of α-GalCer analogs on NO/ROS/TNF-α production in LPS-stimulated microglial cells.a
Mentions: To investigate the anti-inflammatory effects of systematically designed α-GalCer analogs in microglial activation, BV2 cells were treated with compounds 1 h prior to stimulation with LPS, and the inhibitory effects of each α-GalCer analog on LPS-induced production of NO, ROS, and TNF-α were examined. As shown in Figure 5, we measured the percent inhibition of NO, ROS, and TNF-α production upon treatment with 25 α-GalCer analogs at 5 µM concentration. It is worth mentioning that known α-GalCer that are known to be bioactive in iNKT cells showed no or marginal inhibitory effects on LPS-stimulated microglia. For example, KRN7000, a representative α-GalCer, showed an inhibitory effect only on ROS production (24.4% inhibition) but no effect on the production of NO (3.9% inhibition) or TNF-α (1.5% inhibition). In the case of OCH, a known immunomodulatory α-GalCer in iNKT cells, we observed increased production of NO (15.1%) and only slight inhibitory effects on the production of ROS (12.5% inhibition) and TNF-α (13.6% inhibition). When we tested our TH2-selective α-GalCer analog 1c[25], there were marginal inhibitory activities in LPS-induced microglial cells.

Bottom Line: Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia.After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis.Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Medicine and Global Top5 Research Program, Tissue Injury Defense Research Center, Ewha Womans University Medical School, Seoul, Republic of Korea.

ABSTRACT
Microglial activation plays a pivotal role in the development and progression of neurodegenerative diseases. Thus, anti-inflammatory agents that control microglial activation can serve as potential therapeutic agents for neurodegenerative diseases. Here, we designed and synthesized α-galactosylceramide (α-GalCer) analogs to exert anti-inflammatory effects in activated microglia. We performed biological evaluations of 25 α-GalCer analogs and observed an interesting preliminary structure-activity relationship in their inhibitory influence on NO release and TNF-α production in LPS-stimulated BV2 microglial cells. After identification of 4d and 4e as hit compounds, we further investigated the underlying mechanism of their anti-inflammatory effects using RT-PCR analysis. We confirmed that 4d and 4e regulate the expression of iNOS, COX-2, IL-1β, and IL-6 at the mRNA level and the expression of TNF-α at the post-transcriptional level. In addition, both 4d and 4e inhibited LPS-induced DNA binding activities of NF-κB and AP-1 and phosphorylation of p38 MAPK without affecting other MAP kinases. When we examined the anti-inflammatory effect of a p38 MAPK-specific inhibitor, SB203580, on microglial activation, we observed an identical inhibitory pattern as that of 4d and 4e, not only on NO and TNF-α production but also on the DNA binding activities of NF-κB and AP-1. Taken together, these results suggest that p38 MAPK plays an important role in the anti-inflammatory effects of 4d and 4e via the modulation of NF-κB and AP-1 activities.

Show MeSH
Related in: MedlinePlus