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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

The time-dependent effect of LPS and DOM on rat neonatal microglia TGF-β1 release. Rat neonatal microglia (2.8–5.0 x 106 cells/culture dish) were treated with LPS [3 ng/mL] or DOM [1mM] for 4 to 24 hours. TGF-β1 was determined as described in Experimental. Data (pg/mL) are expressed as mean ± SE of 5–6 independent experiments.
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f7-md503113: The time-dependent effect of LPS and DOM on rat neonatal microglia TGF-β1 release. Rat neonatal microglia (2.8–5.0 x 106 cells/culture dish) were treated with LPS [3 ng/mL] or DOM [1mM] for 4 to 24 hours. TGF-β1 was determined as described in Experimental. Data (pg/mL) are expressed as mean ± SE of 5–6 independent experiments.

Mentions: In order to determine whether a 4 to 24 hour stimulation of microglia with domoic acid [1mM] or LPS [3 ng/mL] in vitro caused TGF-β1 protein release, the cell-free media from the same cell culture dishes containing microglia used for TGF-β1 mRNA analysis shown in Figures 5 and 6 were assayed with a rat-specific ELISA (see Experimental). As shown in Figure 7, in LPS [3 ng/mL]-treated microglia TGF-β1 levels remained unchanged: by 4, 8, 16 and 24 hours TGF-β1 levels were 219.4 ± 13.3, 267 ± 34.4, 216 ± 19.4, 244 ± 13.0 pg/mL (n=5), respectively vs. 255.3 ± 27.3 pg/mL (untreated controls, n=5), P > 0.05. Similarly, in domoic acid [1mM]-treated microglia although TGF-β1 levels appeared to decrease after 4, 8, 16 and 24 hours, the differences were non-statistically significant: 198 ± 17, 201 ± 21.4, 173 ± 15.7, 207 ± 27 pg/mL (n=6), respectively, vs. 255.3 ± 27.3 pg/mL (untreated controls, n=5), P > 0.05.


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)

The time-dependent effect of LPS and DOM on rat neonatal microglia TGF-β1 release. Rat neonatal microglia (2.8–5.0 x 106 cells/culture dish) were treated with LPS [3 ng/mL] or DOM [1mM] for 4 to 24 hours. TGF-β1 was determined as described in Experimental. Data (pg/mL) are expressed as mean ± SE of 5–6 independent experiments.
© Copyright Policy
Related In: Results  -  Collection

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

f7-md503113: The time-dependent effect of LPS and DOM on rat neonatal microglia TGF-β1 release. Rat neonatal microglia (2.8–5.0 x 106 cells/culture dish) were treated with LPS [3 ng/mL] or DOM [1mM] for 4 to 24 hours. TGF-β1 was determined as described in Experimental. Data (pg/mL) are expressed as mean ± SE of 5–6 independent experiments.
Mentions: In order to determine whether a 4 to 24 hour stimulation of microglia with domoic acid [1mM] or LPS [3 ng/mL] in vitro caused TGF-β1 protein release, the cell-free media from the same cell culture dishes containing microglia used for TGF-β1 mRNA analysis shown in Figures 5 and 6 were assayed with a rat-specific ELISA (see Experimental). As shown in Figure 7, in LPS [3 ng/mL]-treated microglia TGF-β1 levels remained unchanged: by 4, 8, 16 and 24 hours TGF-β1 levels were 219.4 ± 13.3, 267 ± 34.4, 216 ± 19.4, 244 ± 13.0 pg/mL (n=5), respectively vs. 255.3 ± 27.3 pg/mL (untreated controls, n=5), P > 0.05. Similarly, in domoic acid [1mM]-treated microglia although TGF-β1 levels appeared to decrease after 4, 8, 16 and 24 hours, the differences were non-statistically significant: 198 ± 17, 201 ± 21.4, 173 ± 15.7, 207 ± 27 pg/mL (n=6), respectively, vs. 255.3 ± 27.3 pg/mL (untreated controls, n=5), P > 0.05.

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