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Panax Notoginseng flower saponins (PNFS) inhibit LPS-stimulated NO overproduction and iNOS gene overexpression via the suppression of TLR4-mediated MAPK/NF-kappa B signaling pathways in RAW264.7 macrophages.

Peng XX, Zhang SH, Wang XL, Ye TJ, Li H, Yan XF, Wei L, Wu ZP, Hu J, Zou CP, Wang YH, Hu XD - Chin Med (2015)

Bottom Line: PNFS (50, 100, 200 μg/mL) significantly reduced LPS-induced overproduction of NO (P < 0.001, P < 0.001, P < 0.001) and IL-6 (P = 0.103, P < 0.001, P < 0.001), but did not affect TNF-alpha overproduction.PNFS (50, 100, 200 μg/mL) also markedly decreased LPS-activated iNOS (P < 0.001, P < 0.001, P < 0.001) and TLR4 gene overexpression (P = 0.858, P = 0.046, P = 0.005).PNFS significantly down-regulated iNOS gene overexpression and thereby decreased NO overproduction via the inhibition of TLR4-mediated MAPK/NF-kappa B signaling pathways, but not the PI3K/Akt signaling pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203 People's Republic of China.

ABSTRACT

Background: Panax Notoginseng flower saponins (PNFS) are the main active component of Panax notoginseng (Burk) F. H. Chen flower bud (PNF) and possess significant anti-inflammatory efficacy. This study aims to explore the mechanisms underlying PNFS' antiflammatory action in RAW264.7 macrophages.

Methods: A cell counting kit-8 assay was used to determine the viability of RAW264.7 macrophages. Anti-inflammation effects of PNFS in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were measured based on the detection of nitric oxide (NO) overproduction (Griess method, DAF-FM DA fluorescence assay and NO2 (-) scavenging assay), and interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha gene overexpression (real-time PCR and ELISA). Inducible nitric oxide synthase (iNOS) gene overexpression was determined by real-time PCR and western blotting. iNOS enzyme activity was also assayed. The mechanisms underlying the suppression of iNOS gene overexpression by PNFS were explored using real-time PCR and western blotting to assess mRNA and protein levels of components of the Toll-like receptor 4 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor-kappa B (NF-kappa B) signaling pathways.

Results: PNFS (50, 100, 200 μg/mL) significantly reduced LPS-induced overproduction of NO (P < 0.001, P < 0.001, P < 0.001) and IL-6 (P = 0.103, P < 0.001, P < 0.001), but did not affect TNF-alpha overproduction. PNFS (50, 100, 200 μg/mL) also markedly decreased LPS-activated iNOS (P < 0.001, P < 0.001, P < 0.001) and TLR4 gene overexpression (P = 0.858, P = 0.046, P = 0.005). Furthermore, treatment with PNFS (200 μg/mL) suppressed the phosphorylation of MAPKs including P38 (P = 0.001), c-Jun N-terminal kinase (JNK) (P = 0.036) and extracellular-signal regulated kinase (ERK) 1/2 (P = 0.021). PNFS (200 μg/mL) inhibited the activation of the NF-kappa B signaling pathway by preventing the phosphorylation of inhibitor of NF-kappa B alpha (I-kappa B alpha) (P = 0.004) and P65 (P = 0.023), but PNFS (200 μg/mL) could not activate the LPS-induced PI3K-Akt signaling pathway.

Conclusions: PNFS significantly down-regulated iNOS gene overexpression and thereby decreased NO overproduction via the inhibition of TLR4-mediated MAPK/NF-kappa B signaling pathways, but not the PI3K/Akt signaling pathway.

No MeSH data available.


Related in: MedlinePlus

PNFS did not activate LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages. a PNFS had no effect on PI3K production in LPS-stimulated RAW264.7 macrophages. b PNFS had no effect on P-Akt (Thr308) production in LPS-stimulated RAW264.7 macrophages. Data in Fig. 7a and b were both expressed as the mean (SD) of 3 independent experiments. One-Way ANOVA test was used to analyzed the data and the results were F = 0.999; P = 0.422 and F = 0.157; P = 0.858, respectively. Then, data in Fig. 7a and b were both counted by SNK and LSD multiple comparisons to determine the statistical difference between two groups. The P values represented the statistical differences between each group and the corresponding positive control (without PNFS and with LPS treated)
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Fig7: PNFS did not activate LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages. a PNFS had no effect on PI3K production in LPS-stimulated RAW264.7 macrophages. b PNFS had no effect on P-Akt (Thr308) production in LPS-stimulated RAW264.7 macrophages. Data in Fig. 7a and b were both expressed as the mean (SD) of 3 independent experiments. One-Way ANOVA test was used to analyzed the data and the results were F = 0.999; P = 0.422 and F = 0.157; P = 0.858, respectively. Then, data in Fig. 7a and b were both counted by SNK and LSD multiple comparisons to determine the statistical difference between two groups. The P values represented the statistical differences between each group and the corresponding positive control (without PNFS and with LPS treated)

Mentions: iNOS gene expression can be suppressed via activating the PI3K/Akt signaling pathway [27]. In this study, the effects of PNFS on the LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages were evaluated. After cells were incubated with LPS (1 μg/mL) and PNFS (0, 200 μg/mL) for 3 h, we used western blotting to measure the levels of PI3K and phospho-Akt (P-Akt) (Thr308). PNFS (200 μg/mL) did not affect levels of PI3K or P-Akt (Thr308) (Fig. 7a and b), suggesting that the PI3K/Akt signaling pathway might not be involved in the mechanism by which PNFS suppresses iNOS gene overexpression.Fig. 7


Panax Notoginseng flower saponins (PNFS) inhibit LPS-stimulated NO overproduction and iNOS gene overexpression via the suppression of TLR4-mediated MAPK/NF-kappa B signaling pathways in RAW264.7 macrophages.

Peng XX, Zhang SH, Wang XL, Ye TJ, Li H, Yan XF, Wei L, Wu ZP, Hu J, Zou CP, Wang YH, Hu XD - Chin Med (2015)

PNFS did not activate LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages. a PNFS had no effect on PI3K production in LPS-stimulated RAW264.7 macrophages. b PNFS had no effect on P-Akt (Thr308) production in LPS-stimulated RAW264.7 macrophages. Data in Fig. 7a and b were both expressed as the mean (SD) of 3 independent experiments. One-Way ANOVA test was used to analyzed the data and the results were F = 0.999; P = 0.422 and F = 0.157; P = 0.858, respectively. Then, data in Fig. 7a and b were both counted by SNK and LSD multiple comparisons to determine the statistical difference between two groups. The P values represented the statistical differences between each group and the corresponding positive control (without PNFS and with LPS treated)
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Related In: Results  -  Collection

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Fig7: PNFS did not activate LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages. a PNFS had no effect on PI3K production in LPS-stimulated RAW264.7 macrophages. b PNFS had no effect on P-Akt (Thr308) production in LPS-stimulated RAW264.7 macrophages. Data in Fig. 7a and b were both expressed as the mean (SD) of 3 independent experiments. One-Way ANOVA test was used to analyzed the data and the results were F = 0.999; P = 0.422 and F = 0.157; P = 0.858, respectively. Then, data in Fig. 7a and b were both counted by SNK and LSD multiple comparisons to determine the statistical difference between two groups. The P values represented the statistical differences between each group and the corresponding positive control (without PNFS and with LPS treated)
Mentions: iNOS gene expression can be suppressed via activating the PI3K/Akt signaling pathway [27]. In this study, the effects of PNFS on the LPS-stimulated PI3K/Akt signaling pathway in RAW264.7 macrophages were evaluated. After cells were incubated with LPS (1 μg/mL) and PNFS (0, 200 μg/mL) for 3 h, we used western blotting to measure the levels of PI3K and phospho-Akt (P-Akt) (Thr308). PNFS (200 μg/mL) did not affect levels of PI3K or P-Akt (Thr308) (Fig. 7a and b), suggesting that the PI3K/Akt signaling pathway might not be involved in the mechanism by which PNFS suppresses iNOS gene overexpression.Fig. 7

Bottom Line: PNFS (50, 100, 200 μg/mL) significantly reduced LPS-induced overproduction of NO (P < 0.001, P < 0.001, P < 0.001) and IL-6 (P = 0.103, P < 0.001, P < 0.001), but did not affect TNF-alpha overproduction.PNFS (50, 100, 200 μg/mL) also markedly decreased LPS-activated iNOS (P < 0.001, P < 0.001, P < 0.001) and TLR4 gene overexpression (P = 0.858, P = 0.046, P = 0.005).PNFS significantly down-regulated iNOS gene overexpression and thereby decreased NO overproduction via the inhibition of TLR4-mediated MAPK/NF-kappa B signaling pathways, but not the PI3K/Akt signaling pathway.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203 People's Republic of China.

ABSTRACT

Background: Panax Notoginseng flower saponins (PNFS) are the main active component of Panax notoginseng (Burk) F. H. Chen flower bud (PNF) and possess significant anti-inflammatory efficacy. This study aims to explore the mechanisms underlying PNFS' antiflammatory action in RAW264.7 macrophages.

Methods: A cell counting kit-8 assay was used to determine the viability of RAW264.7 macrophages. Anti-inflammation effects of PNFS in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages were measured based on the detection of nitric oxide (NO) overproduction (Griess method, DAF-FM DA fluorescence assay and NO2 (-) scavenging assay), and interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha gene overexpression (real-time PCR and ELISA). Inducible nitric oxide synthase (iNOS) gene overexpression was determined by real-time PCR and western blotting. iNOS enzyme activity was also assayed. The mechanisms underlying the suppression of iNOS gene overexpression by PNFS were explored using real-time PCR and western blotting to assess mRNA and protein levels of components of the Toll-like receptor 4 mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Akt, and nuclear factor-kappa B (NF-kappa B) signaling pathways.

Results: PNFS (50, 100, 200 μg/mL) significantly reduced LPS-induced overproduction of NO (P < 0.001, P < 0.001, P < 0.001) and IL-6 (P = 0.103, P < 0.001, P < 0.001), but did not affect TNF-alpha overproduction. PNFS (50, 100, 200 μg/mL) also markedly decreased LPS-activated iNOS (P < 0.001, P < 0.001, P < 0.001) and TLR4 gene overexpression (P = 0.858, P = 0.046, P = 0.005). Furthermore, treatment with PNFS (200 μg/mL) suppressed the phosphorylation of MAPKs including P38 (P = 0.001), c-Jun N-terminal kinase (JNK) (P = 0.036) and extracellular-signal regulated kinase (ERK) 1/2 (P = 0.021). PNFS (200 μg/mL) inhibited the activation of the NF-kappa B signaling pathway by preventing the phosphorylation of inhibitor of NF-kappa B alpha (I-kappa B alpha) (P = 0.004) and P65 (P = 0.023), but PNFS (200 μg/mL) could not activate the LPS-induced PI3K-Akt signaling pathway.

Conclusions: PNFS significantly down-regulated iNOS gene overexpression and thereby decreased NO overproduction via the inhibition of TLR4-mediated MAPK/NF-kappa B signaling pathways, but not the PI3K/Akt signaling pathway.

No MeSH data available.


Related in: MedlinePlus