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Differential effects of domoic acid and E. coli lipopolysaccharide on tumor necrosis factor-alpha, transforming growth factor-beta1 and matrix metalloproteinase-9 release by rat neonatal microglia: evaluation of the direct activation hypothesis.

Mayer AM, Guzman M, Peksa R, Hall M, Fay MJ, Jacobson PB, Romanic AM, Gunasekera SP - Mar Drugs (2007)

Bottom Line: LPS [3 ng/mL] but not domoic acid [1 mM] stimulated a statistically significant increase in TNF-alpha mRNA and protein generation.Furthermore, both LPS and domoic acid did not significantly affect TGF-beta1 gene expression and protein release.However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, Illinois 60515, USA. amayer@midwestern.edu

ABSTRACT
The excitatory amino acid domoic acid is the causative agent of amnesic shellfish poisoning in humans. The in vitro effects of domoic acid on rat neonatal brain microglia were compared with E. coli lipopolysaccharide (LPS), a known activator of microglia mediator release over a 4 to 24 hour observation period. LPS [3 ng/mL] but not domoic acid [1 mM] stimulated a statistically significant increase in TNF-alpha mRNA and protein generation. Furthermore, both LPS and domoic acid did not significantly affect TGF-beta1 gene expression and protein release. Finally, an in vitro exposure of microglia to LPS resulted in statistically significant MMP-9 expression and release, thus extending and confirming our previous observations. However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment. Taken together our observations do not support the hypothesis that a short term (4 to 24 hours) in vitro exposure to domoic acid, at a concentration toxic to neuronal cells, activates rat neonatal microglia and the concomitant release of the pro-inflammatory mediators tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinases-9 (MMP-9), as well as the anti-inflammatory cytokine transforming growth factor beta1 (TGF-beta1).

No MeSH data available.


Related in: MedlinePlus

Time-dependent TGF-β1 gene expression levels in rat neonatal microglia after in vitro treatment with LPS or DOM. Levels of gene expression were quantified as described in Experimental and were normalized to S12 ribosomal RNA. Relative expression levels were calculated by dividing the experimental level at each time point by the level observed in the control. Expression is relative to steady-state levels in control (1.00). Data (relative expression level) is expressed as mean ± SE of 2 independent experiments.
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f6-md503113: Time-dependent TGF-β1 gene expression levels in rat neonatal microglia after in vitro treatment with LPS or DOM. Levels of gene expression were quantified as described in Experimental and were normalized to S12 ribosomal RNA. Relative expression levels were calculated by dividing the experimental level at each time point by the level observed in the control. Expression is relative to steady-state levels in control (1.00). Data (relative expression level) is expressed as mean ± SE of 2 independent experiments.

Mentions: Furthermore, as shown in Figure 6, LPS [3 ng/mL] induced non-statistically significant alterations in TGF-β1 expression levels relative to controls which were 0.931±0.19 fold by 4 hours, 0.901±0.22 fold by 8 hours, then slightly decreasing to 0.671±0.05 fold by 16 hours, and returning to near control levels (0.821±0.15 fold) by 24 hours. Similarly, domoic acid [1mM] induced non-statistically significant alterations in levels of TGF-β1 expression which were 0.625 fold by 4 hours (n=1) and 0.923±0.09, 1.01±0.1 fold and 0.977±0.206 fold by 8, 16 and 24 hours, respectively.


Differential effects of domoic acid and E. coli lipopolysaccharide on tumor necrosis factor-alpha, transforming growth factor-beta1 and matrix metalloproteinase-9 release by rat neonatal microglia: evaluation of the direct activation hypothesis.

Mayer AM, Guzman M, Peksa R, Hall M, Fay MJ, Jacobson PB, Romanic AM, Gunasekera SP - Mar Drugs (2007)

Time-dependent TGF-β1 gene expression levels in rat neonatal microglia after in vitro treatment with LPS or DOM. Levels of gene expression were quantified as described in Experimental and were normalized to S12 ribosomal RNA. Relative expression levels were calculated by dividing the experimental level at each time point by the level observed in the control. Expression is relative to steady-state levels in control (1.00). Data (relative expression level) is expressed as mean ± SE of 2 independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2367328&req=5

f6-md503113: Time-dependent TGF-β1 gene expression levels in rat neonatal microglia after in vitro treatment with LPS or DOM. Levels of gene expression were quantified as described in Experimental and were normalized to S12 ribosomal RNA. Relative expression levels were calculated by dividing the experimental level at each time point by the level observed in the control. Expression is relative to steady-state levels in control (1.00). Data (relative expression level) is expressed as mean ± SE of 2 independent experiments.
Mentions: Furthermore, as shown in Figure 6, LPS [3 ng/mL] induced non-statistically significant alterations in TGF-β1 expression levels relative to controls which were 0.931±0.19 fold by 4 hours, 0.901±0.22 fold by 8 hours, then slightly decreasing to 0.671±0.05 fold by 16 hours, and returning to near control levels (0.821±0.15 fold) by 24 hours. Similarly, domoic acid [1mM] induced non-statistically significant alterations in levels of TGF-β1 expression which were 0.625 fold by 4 hours (n=1) and 0.923±0.09, 1.01±0.1 fold and 0.977±0.206 fold by 8, 16 and 24 hours, respectively.

Bottom Line: LPS [3 ng/mL] but not domoic acid [1 mM] stimulated a statistically significant increase in TNF-alpha mRNA and protein generation.Furthermore, both LPS and domoic acid did not significantly affect TGF-beta1 gene expression and protein release.However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, Illinois 60515, USA. amayer@midwestern.edu

ABSTRACT
The excitatory amino acid domoic acid is the causative agent of amnesic shellfish poisoning in humans. The in vitro effects of domoic acid on rat neonatal brain microglia were compared with E. coli lipopolysaccharide (LPS), a known activator of microglia mediator release over a 4 to 24 hour observation period. LPS [3 ng/mL] but not domoic acid [1 mM] stimulated a statistically significant increase in TNF-alpha mRNA and protein generation. Furthermore, both LPS and domoic acid did not significantly affect TGF-beta1 gene expression and protein release. Finally, an in vitro exposure of microglia to LPS resulted in statistically significant MMP-9 expression and release, thus extending and confirming our previous observations. However, in contrast, no statistically significant increase in MMP-9 expression and release was observed after domoic acid treatment. Taken together our observations do not support the hypothesis that a short term (4 to 24 hours) in vitro exposure to domoic acid, at a concentration toxic to neuronal cells, activates rat neonatal microglia and the concomitant release of the pro-inflammatory mediators tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinases-9 (MMP-9), as well as the anti-inflammatory cytokine transforming growth factor beta1 (TGF-beta1).

No MeSH data available.


Related in: MedlinePlus