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Signaling function of Na,K-ATPase induced by ouabain against LPS as an inflammation model in hippocampus.

Kinoshita PF, Yshii LM, Vasconcelos AR, Orellana AM, Lima Lde S, Davel AP, Rossoni LV, Kawamoto EM, Scavone C - J Neuroinflammation (2014)

Bottom Line: The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus.Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus.This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.

View Article: PubMed Central - PubMed

Affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. paula.f.kinoshita@gmail.com.

ABSTRACT

Background: Ouabain (OUA) is a newly recognized hormone that is synthesized in the adrenal cortex and hypothalamus. Low doses of OUA can activate a signaling pathway by interaction with Na,K-ATPase, which is protective against a number of insults. OUA has central and peripheral anti-inflammatory effects. Lipopolysaccharide (LPS), via toll-like receptor 4 activation, is a widely used model to induce systemic inflammation. This study used a low OUA dose to evaluate its effects on inflammation induced by LPS injection in rats.

Methods: Adult male Wistar rats received acute intraperitoneal (ip) OUA (1.8 μg/kg) or saline 20 minutes before LPS (200 μg/kg, ip) or saline injection. Some of the animals had their femoral artery catheterized in order to assess arterial blood pressure values before and after OUA administration. Na,K-ATPase activity, cytokine mRNA levels, apoptosis-related proteins, NF-κB activation brain-derived neurotrophic factor BDNF, corticosterone and TNF-α levels were measured.

Results: OUA pretreatment decreased mRNA levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and IL-1β, which are activated by LPS in the hippocampus, but with no effect on serum measures of these factors. None of these OUA effects were linked to Na,K-ATPase activity. The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus. OUA pretreatment reversed the LPS-induced glial fibrillary acidic protein (GFAP) activation and associated inflammation in the dentate gyrus. OUA also prevented LPS-induced increases in the hippocampal Bax/Bcl2 ratio suggesting an anti-apoptotic action in the brain.

Conclusion: Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus. This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.

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Effects of ouabain (OUA) pretreatment(1.8 μg/kg)on lipopolysaccharide (LPS)-induced(200 μg/kg)serum corticosterone and TNF-α. (A) The serum levels of corticosterone were elevated in LPS and OUA + LPS in comparison with control and OUA group, aP < 0.01 versus control and OUA and bP < 0.01 versus control and OUA. (B) The same pattern occurs in TNF-α serum levels, aP < 0.05 versus control and OUA and bP < 0.05 versus control and OUA. Data are presented as mean ± SEM from five individual experiments. One-way ANOVA followed by Newman-Keuls post-test.
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Fig5: Effects of ouabain (OUA) pretreatment(1.8 μg/kg)on lipopolysaccharide (LPS)-induced(200 μg/kg)serum corticosterone and TNF-α. (A) The serum levels of corticosterone were elevated in LPS and OUA + LPS in comparison with control and OUA group, aP < 0.01 versus control and OUA and bP < 0.01 versus control and OUA. (B) The same pattern occurs in TNF-α serum levels, aP < 0.05 versus control and OUA and bP < 0.05 versus control and OUA. Data are presented as mean ± SEM from five individual experiments. One-way ANOVA followed by Newman-Keuls post-test.

Mentions: Our data showed that LPS, but not OUA, increased serum levels of corticosterone and TNF-α (Figure 5A and B). In addition, OUA pretreatment was unable to block LPS-induced increases in serum corticosterone and TNF-α.Figure 5


Signaling function of Na,K-ATPase induced by ouabain against LPS as an inflammation model in hippocampus.

Kinoshita PF, Yshii LM, Vasconcelos AR, Orellana AM, Lima Lde S, Davel AP, Rossoni LV, Kawamoto EM, Scavone C - J Neuroinflammation (2014)

Effects of ouabain (OUA) pretreatment(1.8 μg/kg)on lipopolysaccharide (LPS)-induced(200 μg/kg)serum corticosterone and TNF-α. (A) The serum levels of corticosterone were elevated in LPS and OUA + LPS in comparison with control and OUA group, aP < 0.01 versus control and OUA and bP < 0.01 versus control and OUA. (B) The same pattern occurs in TNF-α serum levels, aP < 0.05 versus control and OUA and bP < 0.05 versus control and OUA. Data are presented as mean ± SEM from five individual experiments. One-way ANOVA followed by Newman-Keuls post-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4307894&req=5

Fig5: Effects of ouabain (OUA) pretreatment(1.8 μg/kg)on lipopolysaccharide (LPS)-induced(200 μg/kg)serum corticosterone and TNF-α. (A) The serum levels of corticosterone were elevated in LPS and OUA + LPS in comparison with control and OUA group, aP < 0.01 versus control and OUA and bP < 0.01 versus control and OUA. (B) The same pattern occurs in TNF-α serum levels, aP < 0.05 versus control and OUA and bP < 0.05 versus control and OUA. Data are presented as mean ± SEM from five individual experiments. One-way ANOVA followed by Newman-Keuls post-test.
Mentions: Our data showed that LPS, but not OUA, increased serum levels of corticosterone and TNF-α (Figure 5A and B). In addition, OUA pretreatment was unable to block LPS-induced increases in serum corticosterone and TNF-α.Figure 5

Bottom Line: The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus.Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus.This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.

View Article: PubMed Central - PubMed

Affiliation: Molecular Neuropharmacology Laboratory, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, 05508-900, São Paulo, Brazil. paula.f.kinoshita@gmail.com.

ABSTRACT

Background: Ouabain (OUA) is a newly recognized hormone that is synthesized in the adrenal cortex and hypothalamus. Low doses of OUA can activate a signaling pathway by interaction with Na,K-ATPase, which is protective against a number of insults. OUA has central and peripheral anti-inflammatory effects. Lipopolysaccharide (LPS), via toll-like receptor 4 activation, is a widely used model to induce systemic inflammation. This study used a low OUA dose to evaluate its effects on inflammation induced by LPS injection in rats.

Methods: Adult male Wistar rats received acute intraperitoneal (ip) OUA (1.8 μg/kg) or saline 20 minutes before LPS (200 μg/kg, ip) or saline injection. Some of the animals had their femoral artery catheterized in order to assess arterial blood pressure values before and after OUA administration. Na,K-ATPase activity, cytokine mRNA levels, apoptosis-related proteins, NF-κB activation brain-derived neurotrophic factor BDNF, corticosterone and TNF-α levels were measured.

Results: OUA pretreatment decreased mRNA levels of the pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and IL-1β, which are activated by LPS in the hippocampus, but with no effect on serum measures of these factors. None of these OUA effects were linked to Na,K-ATPase activity. The involvement of the inflammatory transcription factor NF-κB in the OUA effect was indicated by its prevention of LPS-induced nuclear translocation of the NF-κB subunit, RELA (p65), as well as the decreased cytosol levels of the NF-κB inhibitor, IKB, in the hippocampus. OUA pretreatment reversed the LPS-induced glial fibrillary acidic protein (GFAP) activation and associated inflammation in the dentate gyrus. OUA also prevented LPS-induced increases in the hippocampal Bax/Bcl2 ratio suggesting an anti-apoptotic action in the brain.

Conclusion: Our results suggest that a low dose of OUA has an important anti-inflammatory effect in the rat hippocampus. This effect was associated with decreased GFAP induction by LPS in the dentate gyrus, a brain area linked to adult neurogenesis.

Show MeSH