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Glutathione peroxidase-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

Bozinovski S, Seow HJ, Crack PJ, Anderson GP, Vlahos R - PLoS ONE (2012)

Bottom Line: To understand the basis for this paradoxical reduction we assessed inflammatory cytokines and proteases at protein and transcript levels.These attenuated protein levels were unexpectedly not mirrored by reduced mRNA transcripts but were associated with increased 20S proteasome expression.Thus, these data suggest that gpx-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, The University of Melbourne, Victoria, Australia.

ABSTRACT
Reactive oxygen species produced during the innate immune response to LPS are important agents of anti-pathogen defence but may also cause oxidative lung damage. Glutathione peroxidase-1 (gpx-1) is an anti-oxidant enzyme that may protect lungs from such damage. We assessed the in vivo importance of gpx-1 in LPS-induced lung inflammation. Male wild-type (WT) or gpx-1 deficient (gpx-1(-/-)) mice were treated intranasally with PBS or 10 µg LPS and killed 3 and 24 h post LPS. Lungs were lavaged with PBS and then harvested for inflammatory marker expression. LPS caused an intense neutrophilia in WT BALF evident 3 and 24 h post challenge that was reduced in gpx-1(-/-) mice. In addition, LPS-treated gpx-1(-/-) mice had significantly fewer macrophages than LPS-treated WT mice. To understand the basis for this paradoxical reduction we assessed inflammatory cytokines and proteases at protein and transcript levels. MMP-9 expression and net gelatinase activity in BALF of gpx-1(-/-) mice treated with LPS for 3 and 24 h was no different to that found in LPS-treated WT mice. BALF from LPS-treated gpx-1(-/-) mice (3 h) had less TNF-α, MIP-2 and GM-CSF protein than LPS-treated WT mice. In contrast, LPS-induced increases in TNF-α, MIP-2 and GM-CSF mRNA expression in WT mice were similar to those observed in gpx-1(-/-) mice. These attenuated protein levels were unexpectedly not mirrored by reduced mRNA transcripts but were associated with increased 20S proteasome expression. Thus, these data suggest that gpx-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

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Effect of LPS on 20S proteasome concentrations in BALF of WT and gpx-1−/− mice.WT and gpx-1−/− mice were treated with LPS (10 µg/mouse) for 3 h and 20S proteasome concentrations measured in BALF. Data are shown as the mean for BALF pooled from 5–6 individual mice per treatment group. Clear bars represent PBS-treated mice and black bars represent LPS-treated mice.
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pone-0033172-g006: Effect of LPS on 20S proteasome concentrations in BALF of WT and gpx-1−/− mice.WT and gpx-1−/− mice were treated with LPS (10 µg/mouse) for 3 h and 20S proteasome concentrations measured in BALF. Data are shown as the mean for BALF pooled from 5–6 individual mice per treatment group. Clear bars represent PBS-treated mice and black bars represent LPS-treated mice.

Mentions: The ubiquitin-proteasome system is the major non-lysosomal system for the degradation of short half-life proteins that are involved in basic cellular processes, such as cell-cycle regulation and apoptosis, transcriptional regulation or antigen processing. The proteasome is a multicatalytic proteinase complex that is involved in the selective degradation of proteins. The 20S proteasome is the proteolytic core particle of a large protein degradation complex, the 26S proteasome. In order to explore whether the reduction in BALF TNF-α, MIP-2 and GM-CSF protein observed in LPS-treated gpx-1−/− mice at 3 hours was associated with the ubiquitin-proteasome pathway we measured BALF 20S proteasome concentrations (Figure 6). LPS treatment of WT mice caused a decrease in 20S proteasome levels compared to PBS-treated WT mice. In contrast, LPS-treated gpx-1−/− mice displayed a 2-fold increase in 20S proteasome levels compared to PBS-treated gpx-1−/− mice. Levels of 20S proteasome in PBS-treated gpx-1−/− mice were similar to those of PBS-treated WT mice.


Glutathione peroxidase-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

Bozinovski S, Seow HJ, Crack PJ, Anderson GP, Vlahos R - PLoS ONE (2012)

Effect of LPS on 20S proteasome concentrations in BALF of WT and gpx-1−/− mice.WT and gpx-1−/− mice were treated with LPS (10 µg/mouse) for 3 h and 20S proteasome concentrations measured in BALF. Data are shown as the mean for BALF pooled from 5–6 individual mice per treatment group. Clear bars represent PBS-treated mice and black bars represent LPS-treated mice.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3295802&req=5

pone-0033172-g006: Effect of LPS on 20S proteasome concentrations in BALF of WT and gpx-1−/− mice.WT and gpx-1−/− mice were treated with LPS (10 µg/mouse) for 3 h and 20S proteasome concentrations measured in BALF. Data are shown as the mean for BALF pooled from 5–6 individual mice per treatment group. Clear bars represent PBS-treated mice and black bars represent LPS-treated mice.
Mentions: The ubiquitin-proteasome system is the major non-lysosomal system for the degradation of short half-life proteins that are involved in basic cellular processes, such as cell-cycle regulation and apoptosis, transcriptional regulation or antigen processing. The proteasome is a multicatalytic proteinase complex that is involved in the selective degradation of proteins. The 20S proteasome is the proteolytic core particle of a large protein degradation complex, the 26S proteasome. In order to explore whether the reduction in BALF TNF-α, MIP-2 and GM-CSF protein observed in LPS-treated gpx-1−/− mice at 3 hours was associated with the ubiquitin-proteasome pathway we measured BALF 20S proteasome concentrations (Figure 6). LPS treatment of WT mice caused a decrease in 20S proteasome levels compared to PBS-treated WT mice. In contrast, LPS-treated gpx-1−/− mice displayed a 2-fold increase in 20S proteasome levels compared to PBS-treated gpx-1−/− mice. Levels of 20S proteasome in PBS-treated gpx-1−/− mice were similar to those of PBS-treated WT mice.

Bottom Line: To understand the basis for this paradoxical reduction we assessed inflammatory cytokines and proteases at protein and transcript levels.These attenuated protein levels were unexpectedly not mirrored by reduced mRNA transcripts but were associated with increased 20S proteasome expression.Thus, these data suggest that gpx-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, The University of Melbourne, Victoria, Australia.

ABSTRACT
Reactive oxygen species produced during the innate immune response to LPS are important agents of anti-pathogen defence but may also cause oxidative lung damage. Glutathione peroxidase-1 (gpx-1) is an anti-oxidant enzyme that may protect lungs from such damage. We assessed the in vivo importance of gpx-1 in LPS-induced lung inflammation. Male wild-type (WT) or gpx-1 deficient (gpx-1(-/-)) mice were treated intranasally with PBS or 10 µg LPS and killed 3 and 24 h post LPS. Lungs were lavaged with PBS and then harvested for inflammatory marker expression. LPS caused an intense neutrophilia in WT BALF evident 3 and 24 h post challenge that was reduced in gpx-1(-/-) mice. In addition, LPS-treated gpx-1(-/-) mice had significantly fewer macrophages than LPS-treated WT mice. To understand the basis for this paradoxical reduction we assessed inflammatory cytokines and proteases at protein and transcript levels. MMP-9 expression and net gelatinase activity in BALF of gpx-1(-/-) mice treated with LPS for 3 and 24 h was no different to that found in LPS-treated WT mice. BALF from LPS-treated gpx-1(-/-) mice (3 h) had less TNF-α, MIP-2 and GM-CSF protein than LPS-treated WT mice. In contrast, LPS-induced increases in TNF-α, MIP-2 and GM-CSF mRNA expression in WT mice were similar to those observed in gpx-1(-/-) mice. These attenuated protein levels were unexpectedly not mirrored by reduced mRNA transcripts but were associated with increased 20S proteasome expression. Thus, these data suggest that gpx-1 primes pro-inflammatory cytokine production after LPS challenge in vivo.

Show MeSH
Related in: MedlinePlus