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Extracellular ATP drives systemic inflammation, tissue damage and mortality.

Cauwels A, Rogge E, Vandendriessche B, Shiva S, Brouckaert P - Cell Death Dis (2014)

Bottom Line: Our results indeed indicate an important pro-inflammatory role for extracellular ATP.However, the effect of ATP is not restricted to inflammasome activation at all.Although blocking ATP receptors with the broad-spectrum P2 purinergic receptor antagonist suramin imitated certain beneficial effects of apyrase treatment, it could not prevent morbidity or mortality at all.

View Article: PubMed Central - PubMed

Affiliation: 1] Inflammation Research Center, VIB, Ghent, Belgium [2] Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.

ABSTRACT
Systemic inflammatory response syndromes (SIRS) may be caused by both infectious and sterile insults, such as trauma, ischemia-reperfusion or burns. They are characterized by early excessive inflammatory cytokine production and the endogenous release of several toxic and damaging molecules. These are necessary to fight and resolve the cause of SIRS, but often end up progressively damaging cells and tissues, leading to life-threatening multiple organ dysfunction syndrome (MODS). As inflammasome-dependent cytokines such as interleukin-1β are critically involved in the development of MODS and death in SIRS, and ATP is an essential activator of inflammasomes in vitro, we decided to analyze the ability of ATP removal to prevent excessive tissue damage and mortality in a murine LPS-induced inflammation model. Our results indeed indicate an important pro-inflammatory role for extracellular ATP. However, the effect of ATP is not restricted to inflammasome activation at all. Removing extracellular ATP with systemic apyrase treatment not only prevented IL-1β accumulation but also the production of inflammasome-independent cytokines such as TNF and IL-10. In addition, ATP removal also prevented systemic evidence of cellular disintegration, mitochondrial damage, apoptosis, intestinal barrier disruption and even mortality. Although blocking ATP receptors with the broad-spectrum P2 purinergic receptor antagonist suramin imitated certain beneficial effects of apyrase treatment, it could not prevent morbidity or mortality at all. We conclude that removal of systemic extracellular ATP could be a valuable strategy to dampen systemic inflammatory damage and toxicity in SIRS.

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Apyrase prevents inflammation and tissue damage. (a) CD45 staining quantification in liver sections 6 h after LPS challenge, n=3–7. (b) Hexosaminidase in serum indicates cellular disintegration. Plotted is the relative increase compared with PBS-treated animals, n=7. (c, d) Mitochondrial complex I and II activity in liver tissue 6 h after LPS injection, n=3–4. (e) TUNEL staining of apoptotic cell death in the jejunum, n=4-6. (f) AB/PAS staining was used to visualize mucin-positive goblet cells in the jejunum, n=6–9. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001, compared with LPS (a, b) or PBS controls (c–f), or as indicated by horizontal lines
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fig3: Apyrase prevents inflammation and tissue damage. (a) CD45 staining quantification in liver sections 6 h after LPS challenge, n=3–7. (b) Hexosaminidase in serum indicates cellular disintegration. Plotted is the relative increase compared with PBS-treated animals, n=7. (c, d) Mitochondrial complex I and II activity in liver tissue 6 h after LPS injection, n=3–4. (e) TUNEL staining of apoptotic cell death in the jejunum, n=4-6. (f) AB/PAS staining was used to visualize mucin-positive goblet cells in the jejunum, n=6–9. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001, compared with LPS (a, b) or PBS controls (c–f), or as indicated by horizontal lines

Mentions: Using both genetic and therapeutic approaches, we recently determined the critical involvement of both endogenous IL-1β and IL-18 in several models of inflammatory and septic shock.20 To induce IL-1β/IL-18 maturation and release, the NLRP3 inflammasome is essential, and LPS-induced activation of the inflammasome has been suggested to result from particle internalization and/or ATP signaling.21 Hence, we decided to analyze the effect of apyrase on LPS-induced cytokine induction. As anticipated based on our hypothesis, IL-1 bioactivity and IL-1β protein levels in serum were significantly reduced (Figures 2a and b). Surprisingly, however, we found that also endogenous TNF and IL-10 production were markedly inhibited by apyrase treatment (Figures 2c–e), whereas IL-6 levels were not affected significantly (Figure 2f). Also the production of IL-12 (produced from 2 h on) and IFN-γ (undetectable at 2 h, but systemically present at 6 h), pro-inflammatory cytokines that may link innate with adaptive immunity, was reduced thanks to apyrase treatment, albeit not significantly (not shown). The reduced systemic TNF and IL-1 production was reflected in reduced leukocyte infiltration into liver tissue (Figure 3a).


Extracellular ATP drives systemic inflammation, tissue damage and mortality.

Cauwels A, Rogge E, Vandendriessche B, Shiva S, Brouckaert P - Cell Death Dis (2014)

Apyrase prevents inflammation and tissue damage. (a) CD45 staining quantification in liver sections 6 h after LPS challenge, n=3–7. (b) Hexosaminidase in serum indicates cellular disintegration. Plotted is the relative increase compared with PBS-treated animals, n=7. (c, d) Mitochondrial complex I and II activity in liver tissue 6 h after LPS injection, n=3–4. (e) TUNEL staining of apoptotic cell death in the jejunum, n=4-6. (f) AB/PAS staining was used to visualize mucin-positive goblet cells in the jejunum, n=6–9. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001, compared with LPS (a, b) or PBS controls (c–f), or as indicated by horizontal lines
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3973196&req=5

fig3: Apyrase prevents inflammation and tissue damage. (a) CD45 staining quantification in liver sections 6 h after LPS challenge, n=3–7. (b) Hexosaminidase in serum indicates cellular disintegration. Plotted is the relative increase compared with PBS-treated animals, n=7. (c, d) Mitochondrial complex I and II activity in liver tissue 6 h after LPS injection, n=3–4. (e) TUNEL staining of apoptotic cell death in the jejunum, n=4-6. (f) AB/PAS staining was used to visualize mucin-positive goblet cells in the jejunum, n=6–9. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001, compared with LPS (a, b) or PBS controls (c–f), or as indicated by horizontal lines
Mentions: Using both genetic and therapeutic approaches, we recently determined the critical involvement of both endogenous IL-1β and IL-18 in several models of inflammatory and septic shock.20 To induce IL-1β/IL-18 maturation and release, the NLRP3 inflammasome is essential, and LPS-induced activation of the inflammasome has been suggested to result from particle internalization and/or ATP signaling.21 Hence, we decided to analyze the effect of apyrase on LPS-induced cytokine induction. As anticipated based on our hypothesis, IL-1 bioactivity and IL-1β protein levels in serum were significantly reduced (Figures 2a and b). Surprisingly, however, we found that also endogenous TNF and IL-10 production were markedly inhibited by apyrase treatment (Figures 2c–e), whereas IL-6 levels were not affected significantly (Figure 2f). Also the production of IL-12 (produced from 2 h on) and IFN-γ (undetectable at 2 h, but systemically present at 6 h), pro-inflammatory cytokines that may link innate with adaptive immunity, was reduced thanks to apyrase treatment, albeit not significantly (not shown). The reduced systemic TNF and IL-1 production was reflected in reduced leukocyte infiltration into liver tissue (Figure 3a).

Bottom Line: Our results indeed indicate an important pro-inflammatory role for extracellular ATP.However, the effect of ATP is not restricted to inflammasome activation at all.Although blocking ATP receptors with the broad-spectrum P2 purinergic receptor antagonist suramin imitated certain beneficial effects of apyrase treatment, it could not prevent morbidity or mortality at all.

View Article: PubMed Central - PubMed

Affiliation: 1] Inflammation Research Center, VIB, Ghent, Belgium [2] Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.

ABSTRACT
Systemic inflammatory response syndromes (SIRS) may be caused by both infectious and sterile insults, such as trauma, ischemia-reperfusion or burns. They are characterized by early excessive inflammatory cytokine production and the endogenous release of several toxic and damaging molecules. These are necessary to fight and resolve the cause of SIRS, but often end up progressively damaging cells and tissues, leading to life-threatening multiple organ dysfunction syndrome (MODS). As inflammasome-dependent cytokines such as interleukin-1β are critically involved in the development of MODS and death in SIRS, and ATP is an essential activator of inflammasomes in vitro, we decided to analyze the ability of ATP removal to prevent excessive tissue damage and mortality in a murine LPS-induced inflammation model. Our results indeed indicate an important pro-inflammatory role for extracellular ATP. However, the effect of ATP is not restricted to inflammasome activation at all. Removing extracellular ATP with systemic apyrase treatment not only prevented IL-1β accumulation but also the production of inflammasome-independent cytokines such as TNF and IL-10. In addition, ATP removal also prevented systemic evidence of cellular disintegration, mitochondrial damage, apoptosis, intestinal barrier disruption and even mortality. Although blocking ATP receptors with the broad-spectrum P2 purinergic receptor antagonist suramin imitated certain beneficial effects of apyrase treatment, it could not prevent morbidity or mortality at all. We conclude that removal of systemic extracellular ATP could be a valuable strategy to dampen systemic inflammatory damage and toxicity in SIRS.

Show MeSH
Related in: MedlinePlus