Microarray analyses of the effects of NF-κB or PI3K pathway inhibitors on the LPS-induced gene expression profile in RAW264.7 cells

Mendes, Sofia Dos Santos; Candi, Aurélie; Vansteenbrugge, Martine; Pignon, Marie-Rose; Bult, Hidde; Boudjeltia, Karim Zouaoui; Munaut, Carine; Raes, Martine

doi:10.1016/j.cellsig.2009.02.025

Cited by 55 publications

(18 citation statements)

References 67 publications

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“…Combined with our previous findings that the upregulation of phosphorylated IκB induced by GOS is associated with NF-κB nuclear translocation 20 , we speculated that Akt phosphorylation contributes to GOS-stimulated signalling. In addition, the Akt/mTOR signalling pathway is reported to participate in various processes, including cell growth, autophagy, apoptosis and immune regulation 27 , and activated Akt was found to induce expression of IL-6, TNF-α and IL-12 by initiating phosphorylation of mTOR and p70 S6K 28 . According to current findings (Figs 2D,E and 3), we propose that GOS-mediated immune regulation in RAW264.7 macrophages is divided into the following major steps: (1) GOS the surface receptor TLR4; (2) PI3K is activated by TLR4 and subsequently induces Akt phosphorylation; (3) phosphorylated Akt triggers IκB phosphorylation, resulting in (4) the release and translocation of NF-κB into the nucleus; (5) mTOR and p70 S6K are also activated by p-Akt; (6) all these factors work together or separately to induce the production of inflammatory mediators.…”

Section: Discussionmentioning

confidence: 99%

Identification and activation of TLR4-mediated signalling pathways by alginate-derived guluronate oligosaccharide in RAW264.7 macrophages

Fang

Zheng

et al. 2017

Sci Rep

156

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Alginate, a natural acidic polysaccharide extracted from marine brown seaweeds, is composed of different blocks of β-(1, 4)-D-mannuronate (M) and its C-5 epimer α-(1, 4)-L-guluronate (G). Alginate-derived guluronate oligosaccharide (GOS) readily activates macrophages. However, to understand its role in immune responses, further studies are needed to characterize GOS transport and signalling. Our results show that GOS is recognized by and upregulates Toll-like receptor 4 (TLR4) on RAW264.7 macrophages, followed by its endocytosis via TLR4. Increased expression of TLR4 and myeloid differentiation protein 2 (MD2) results in Akt phosphorylation and subsequent activation of both nuclear factor-κB (NF-κB) and mechanistic target of rapamycin (mTOR). Moreover, GOS stimulates mitogen-activated protein kinases (MAPKs); notably, c-Jun N-terminal kinase (JNK) phosphorylation depends on TLR4 initiation. All these events contribute to the production of inflammatory mediators, either together or separately. Our findings also reveal that GOS induces cytoskeleton remodelling in RAW264.7 cells and promotes macrophage proliferation in mice ascites, both of which improve innate immunity. Conclusively, our investigation demonstrates that GOS, which is dependent on TLR4, is taken up by macrophages and stimulates TLR4/Akt/NF-κB, TLR4/Akt/mTOR and MAPK signalling pathways and exerts impressive immuno-stimulatory activity.

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Section: Discussionmentioning

confidence: 99%

Identification and activation of TLR4-mediated signalling pathways by alginate-derived guluronate oligosaccharide in RAW264.7 macrophages

Fang

Zheng

et al. 2017

Sci Rep

156

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“…MMP-9 production and activity could be induced by LPS, which is a common potent activator of inflammatory responses [22,23,24,25]. In addition, MMP-9 was closely associated with cell migration [4,5].…”

Section: Discussionmentioning

confidence: 99%

Acetylcholine Inhibits LPS-Induced MMP-9 Production and Cell Migration via the a7 nAChR-JAK2/STAT3 Pathway in RAW264.7 Cells

Yang

et al. 2015

Cell Physiol Biochem

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Background: Excessive activation of matrix metalloproteinase 9 (MMP-9) has been found in several inflammatory diseases. Previous studies have shown that acetylcholine (ACh) reduced the levels of pro-inflammatory cytokines and decreased tissue damage. Therefore, this study was designed to explore the potential effects and mechanisms of ACh on MMP-9 production and cell migration in response to lipopolysaccharide (LPS) stimulation in RAW264.7 cells. Methods: MMP-9 expression and activity were induced by LPS in RAW264.7 cells, and examined by real-time PCR, western blotting and gelatin zymography, respectively. ELISA was used to determine the changes in MMP-9 secretion among the groups. Macrophage migration was evaluated using transwell migration assay. Knockdown of a7 nicotinic acetylcholine receptor (a7 nAChR) expression was performed using siRNA transfection. Results: Pre-treatment with ACh inhibited LPS-induced MMP-9 production and macrophage migration in RAW264.7 cells. These effects were abolished by the a7 nAChR antagonist methyllycaconitine (MLA) and a7 nAChR siRNA. The a7 nAChR agonist PNU282987 was found to have an effect similar to that of ACh. Moreover, ACh enhanced the expression of JAK2 and STAT3, and the JAK2 inhibitor AG490 and the STAT3 inhibitor static restored the effect of ACh. Meanwhile, ACh decreased the phosphorylation and nuclear translocation of NF-κB, and this effect was abrogated in the presence of MLA. In addition, the JAK2 and STAT3 inhibitor abolished the inhibitory effects of ACh on phosphorylation of NF-κB. Conclusions: Activation of a7 nAChR by ACh inhibited LPS-induced MMP-9 production and macrophage migration through the JAK2/STAT3 signaling pathway. These results provide novel insights into the anti-inflammatory effects and mechanisms of ACh.

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“…These data may be reasonably explained by the recruitment of different signaling pathways by the two stimuli, and/or by a different timing in recruitment, which can account for the different effects of RAD on NOS2 activity and expression depending on the presence of one or another of the two pro-inflammatory stimuli. Interestingly, both proinflammatory [35,36] and antinflammatory effects [24] have been described in peripheral macrophages in association to mTOR inhibition. Most of the currently available data suggest that mTOR acts as a negative feedback regulator in LPS activated macrophages by blocking NFkB activation and thus reducing the inflammatory responses [20].…”

Section: Discussionmentioning

confidence: 99%

Involvement of mTOR kinase in cytokine-dependent microglial activation and cell proliferation

Russo

Lisi

Tringali

et al. 2009

Biochemical Pharmacology

137

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. Involvement of mTOR kinase in cytokine dependent microglial activation and cell proliferation. Biochemical Pharmacology, Elsevier, 2009, 78 (9) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. It is now evident that the mTOR signaling pathway regulates different functions in the innate immune system, contributing to macrophage activation. More recently, mTOR has been found to enhance the survival of EOC2 microglia during oxygen-glucose deprivation and increase NO synthase 2 (NOS2) expression during hypoxia in BV2 microglial cell line, thus suggesting an involvement in microglial proinflammatory activation. In the present study, we detected mTOR activation in response to two different stimuli, namely LPS and a mixture of cytokines, in primary cultures of rat cortical microglia. Moreover, mTOR inhibitors reduced NOS activity and NOS2 expression induced by cytokines, but not those induced by LPS. The mTOR inhibitor RAD001, in combination with cytokines, also reduced microglial proliferation and the intracellular levels of cyclooxygenase. Under basal conditions mTOR inhibition significantly reduced microglial viability. Interestingly, mTOR inhibitors did not display any relevant effect on astrocyte NOS2 activity or cell viability. In conclusion, mTOR selectively controls microglial activation in response to proinflammatory cytokines and appears to play a crucial role in microglial viability; thus these drugs may be a useful pharmacological tool to reduce neuroinflammation.

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Microarray analyses of the effects of NF-κB or PI3K pathway inhibitors on the LPS-induced gene expression profile in RAW264.7 cells

Cited by 55 publications

References 67 publications

Identification and activation of TLR4-mediated signalling pathways by alginate-derived guluronate oligosaccharide in RAW264.7 macrophages

Identification and activation of TLR4-mediated signalling pathways by alginate-derived guluronate oligosaccharide in RAW264.7 macrophages

Acetylcholine Inhibits LPS-Induced MMP-9 Production and Cell Migration via the a7 nAChR-JAK2/STAT3 Pathway in RAW264.7 Cells

Involvement of mTOR kinase in cytokine-dependent microglial activation and cell proliferation

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