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Modulation of LPS stimulated NF-kappaB mediated Nitric Oxide production by PKCepsilon and JAK2 in RAW macrophages.

Jones E, Adcock IM, Ahmed BY, Punchard NA - J Inflamm (Lond) (2007)

Bottom Line: These effects were associated with changes in p65 nuclear translocation.Furthermore, a partial inhibitory effect on LPS-induced NO release was seen with the JAK2 inhibitor AG-490 and the p38 MAPK inhibitor SB 203850.The results further define the role of NF-kappaB in LPS stimulated NO production in RAW macrophages.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Health & Biosciences, University of East London, London, UK. n.punchard@uel.ac.uk.

ABSTRACT

Background: Nuclear factor kappa B (NF-kappaB) has been shown to play an important role in regulating the expression of many genes involved in cell survival, immunity and in the inflammatory processes. NF-kappaB activation upregulates inducible nitric oxide synthase leading to enhanced nitric oxide production during an inflammatory response. NF-kappaB activation is regulated by distinct kinase pathways independent of inhibitor of kappaB kinase (IKK). Here, we examine the role of protein kinase C isoforms and janus activated kinase 2 (JAK2) activation in NF-kappaB activation and LPS-stimulated NO production.

Methods: Murine RAW 264.7 macrophages were treated with lipopolysaccharide (LPS), Phorbol 12-myristate 13-acetate (PMA) and a combination of LPS and PMA in the presence or absence of various inhibitors of PKC isoforms and JAK2. Nuclear translocation of the NF-kappaB p65 subunit, was assessed by Western blot analysis whilst NO levels were assessed by Greiss assay.

Results: LPS-stimulated NO production was attenuated by PMA whilst PMA alone did not affect NO release. These effects were associated with changes in p65 nuclear translocation. The PKCalpha, beta, gamma, delta and zeta inhibitor Gö 6983 (Go) had no effect on LPS-induced NO release. In contrast, Bisindolymalemide I (Bis), a PKC alpha, betaI, betaII, gamma, delta and epsilon isoform inhibitors completely inhibited LPS-stimulated NO production without affecting p65 nuclear translocation. Furthermore, a partial inhibitory effect on LPS-induced NO release was seen with the JAK2 inhibitor AG-490 and the p38 MAPK inhibitor SB 203850.

Conclusion: The results further define the role of NF-kappaB in LPS stimulated NO production in RAW macrophages. The data support a function for PKCepsilon, JAK2 and p38 MAPK in NF-kappaB activation following p65 nuclear import.

No MeSH data available.


Related in: MedlinePlus

Effect of JAK2 inhibitor on LPS-stimulated NO production in RAW 264.7 cells. Concentration dependent effect of the JAK2 inhibitor AG-490 (0–10 μM) on LPS (1 μg/ml)-stimulated NO production measured at 24 hr. Cells were stimulated and the culture medium harvested and assayed for nitrite content by Greiss assay. The data show that AG-490 was able to inhibit LPS-stimulated NO production. Results for the effects of the inhibitor are expressed mean ± SEM, **p < 0.01 vs no inhibitor, n = 6.
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Figure 6: Effect of JAK2 inhibitor on LPS-stimulated NO production in RAW 264.7 cells. Concentration dependent effect of the JAK2 inhibitor AG-490 (0–10 μM) on LPS (1 μg/ml)-stimulated NO production measured at 24 hr. Cells were stimulated and the culture medium harvested and assayed for nitrite content by Greiss assay. The data show that AG-490 was able to inhibit LPS-stimulated NO production. Results for the effects of the inhibitor are expressed mean ± SEM, **p < 0.01 vs no inhibitor, n = 6.

Mentions: AG-490, a potent inhibitor of JAK2, caused a concentration-dependent inhibition of LPS-stimulated NO production and this was significant at 10 μM (Fig. 6). JAK2 has been shown to be activated in response to a wide variety of stimuli [30] and AG-490 to block induced NOS2 expression in IL-1β/TNFα/IFNγ-stimulated human epithelial-like colon carcinoma DLD-1 cells [31] and in IFNγ/LPS stimulated RAW cells [32]. This present finding extends the previous studies and further indicates the involvement of JAK2 in NF-κB-induced LPS-stimulated NO production and NF-κB activation in RAW cells.


Modulation of LPS stimulated NF-kappaB mediated Nitric Oxide production by PKCepsilon and JAK2 in RAW macrophages.

Jones E, Adcock IM, Ahmed BY, Punchard NA - J Inflamm (Lond) (2007)

Effect of JAK2 inhibitor on LPS-stimulated NO production in RAW 264.7 cells. Concentration dependent effect of the JAK2 inhibitor AG-490 (0–10 μM) on LPS (1 μg/ml)-stimulated NO production measured at 24 hr. Cells were stimulated and the culture medium harvested and assayed for nitrite content by Greiss assay. The data show that AG-490 was able to inhibit LPS-stimulated NO production. Results for the effects of the inhibitor are expressed mean ± SEM, **p < 0.01 vs no inhibitor, n = 6.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC2211292&req=5

Figure 6: Effect of JAK2 inhibitor on LPS-stimulated NO production in RAW 264.7 cells. Concentration dependent effect of the JAK2 inhibitor AG-490 (0–10 μM) on LPS (1 μg/ml)-stimulated NO production measured at 24 hr. Cells were stimulated and the culture medium harvested and assayed for nitrite content by Greiss assay. The data show that AG-490 was able to inhibit LPS-stimulated NO production. Results for the effects of the inhibitor are expressed mean ± SEM, **p < 0.01 vs no inhibitor, n = 6.
Mentions: AG-490, a potent inhibitor of JAK2, caused a concentration-dependent inhibition of LPS-stimulated NO production and this was significant at 10 μM (Fig. 6). JAK2 has been shown to be activated in response to a wide variety of stimuli [30] and AG-490 to block induced NOS2 expression in IL-1β/TNFα/IFNγ-stimulated human epithelial-like colon carcinoma DLD-1 cells [31] and in IFNγ/LPS stimulated RAW cells [32]. This present finding extends the previous studies and further indicates the involvement of JAK2 in NF-κB-induced LPS-stimulated NO production and NF-κB activation in RAW cells.

Bottom Line: These effects were associated with changes in p65 nuclear translocation.Furthermore, a partial inhibitory effect on LPS-induced NO release was seen with the JAK2 inhibitor AG-490 and the p38 MAPK inhibitor SB 203850.The results further define the role of NF-kappaB in LPS stimulated NO production in RAW macrophages.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Health & Biosciences, University of East London, London, UK. n.punchard@uel.ac.uk.

ABSTRACT

Background: Nuclear factor kappa B (NF-kappaB) has been shown to play an important role in regulating the expression of many genes involved in cell survival, immunity and in the inflammatory processes. NF-kappaB activation upregulates inducible nitric oxide synthase leading to enhanced nitric oxide production during an inflammatory response. NF-kappaB activation is regulated by distinct kinase pathways independent of inhibitor of kappaB kinase (IKK). Here, we examine the role of protein kinase C isoforms and janus activated kinase 2 (JAK2) activation in NF-kappaB activation and LPS-stimulated NO production.

Methods: Murine RAW 264.7 macrophages were treated with lipopolysaccharide (LPS), Phorbol 12-myristate 13-acetate (PMA) and a combination of LPS and PMA in the presence or absence of various inhibitors of PKC isoforms and JAK2. Nuclear translocation of the NF-kappaB p65 subunit, was assessed by Western blot analysis whilst NO levels were assessed by Greiss assay.

Results: LPS-stimulated NO production was attenuated by PMA whilst PMA alone did not affect NO release. These effects were associated with changes in p65 nuclear translocation. The PKCalpha, beta, gamma, delta and zeta inhibitor Gö 6983 (Go) had no effect on LPS-induced NO release. In contrast, Bisindolymalemide I (Bis), a PKC alpha, betaI, betaII, gamma, delta and epsilon isoform inhibitors completely inhibited LPS-stimulated NO production without affecting p65 nuclear translocation. Furthermore, a partial inhibitory effect on LPS-induced NO release was seen with the JAK2 inhibitor AG-490 and the p38 MAPK inhibitor SB 203850.

Conclusion: The results further define the role of NF-kappaB in LPS stimulated NO production in RAW macrophages. The data support a function for PKCepsilon, JAK2 and p38 MAPK in NF-kappaB activation following p65 nuclear import.

No MeSH data available.


Related in: MedlinePlus