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Trazodone regulates neurotrophic/growth factors, mitogen-activated protein kinases and lactate release in human primary astrocytes.

Daniele S, Zappelli E, Martini C - J Neuroinflammation (2015)

Bottom Line: TDZ had no effect on cell proliferation, but it decreased pro-inflammatory mediator release and modulated trophic and transcription factor mRNA expression.These effects mainly involved an activation of 5-HT1A and an antagonism at 5-HT2A/C serotonin receptors.Fluoxetine, used in parallel, showed similar final effects nevertheless it activates different receptors/intracellular pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, Pisa, 56126, PI, Italy. simona.daniele@for.unipi.it.

ABSTRACT

Background: In the central nervous system, glial cells provide metabolic and trophic support to neurons and respond to protracted stress and insults by up-regulating inflammatory processes. Reactive astrocytes and microglia are associated with the pathophysiology of neuronal injury, neurodegenerative diseases and major depression, in both animal models and human brains. Several studies have reported clear anti-inflammatory effects of anti-depressant treatment on astrocytes, especially in models of neurological disorders. Trazodone (TDZ) is a triazolopyridine derivative that is structurally unrelated to other major classes of antidepressants. Although the molecular mechanisms of TDZ in neurons have been investigated, it is unclear whether astrocytes are also a TDZ target.

Methods: The effects of TDZ on human astrocytes were investigated in physiological conditions and following inflammatory insult with lipopolysaccharide (LPS) and tumour necrosis factor-α (TNF-α). Astrocytes were assessed for their responses to pro-inflammatory mediators and cytokines, and the receptors and signalling pathways involved in TDZ-mediated effects were evaluated.

Results: TDZ had no effect on cell proliferation, but it decreased pro-inflammatory mediator release and modulated trophic and transcription factor mRNA expression. Following TDZ treatment, the AKT pathway was activated, whereas extracellular signal-regulated kinase and c-Jun NH2-terminal kinase were inhibited. Most importantly, a 72-h TDZ pre-treatment before inflammatory insult completely reversed the anti-proliferative effects induced by LPS-TNF-α. The expression or the activity of inflammatory mediators, including interleukin-6, c-Jun NH2-terminal kinase and nuclear factor κB, were also reduced. Furthermore, TDZ affected astrocyte metabolic support to neurons by counteracting the inflammation-mediated lactate decrease. Finally, TDZ protected neuronal-like cells against neurotoxicity mediated by activated astrocytes. These effects mainly involved an activation of 5-HT1A and an antagonism at 5-HT2A/C serotonin receptors. Fluoxetine, used in parallel, showed similar final effects nevertheless it activates different receptors/intracellular pathways.

Conclusions: Altogether, our results demonstrated that TDZ directly acts on astrocytes by regulating intracellular signalling pathways and increasing specific astrocyte-derived neurotrophic factor expression and lactate release. TDZ may contribute to neuronal support by normalizing trophic and metabolic support during neuroinflammation, which is associated with neurological diseases, including major depression.

No MeSH data available.


Related in: MedlinePlus

Expression of pro-inflammatory genes, trophic and transcription factors in an experimental model of inflammation. a Human astrocytes were treated with 50 μg/ml LPS and 50 ng/ml TNF-α for 24 h. b, c Human astrocytes were treated with medium alone (control), different concentrations of TDZ (100 nM-1 μM), or FLUOX (10 μM) for 24 h (b) or 72 h (c); after drug removal, cells were incubated with 50 μg/ml LPS and 50 ng/ml TNF-α for an additional 24 h. At the end of treatment, total RNA was extracted, and relative mRNA quantification of NF-kB, CREB, mTOR and BDNF was performed by RT-PCR. The data are expressed as fold changes vs. control and represent the mean ± SEM of three different experiments, each performed in duplicate. Statistical significance was determined using a one-way ANOVA-Tukey HSD post hoc test: *P < 0.05, **P < 0.01, ***P < 0.001 vs. control; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. cells treated with LPS-TNF-α
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Fig5: Expression of pro-inflammatory genes, trophic and transcription factors in an experimental model of inflammation. a Human astrocytes were treated with 50 μg/ml LPS and 50 ng/ml TNF-α for 24 h. b, c Human astrocytes were treated with medium alone (control), different concentrations of TDZ (100 nM-1 μM), or FLUOX (10 μM) for 24 h (b) or 72 h (c); after drug removal, cells were incubated with 50 μg/ml LPS and 50 ng/ml TNF-α for an additional 24 h. At the end of treatment, total RNA was extracted, and relative mRNA quantification of NF-kB, CREB, mTOR and BDNF was performed by RT-PCR. The data are expressed as fold changes vs. control and represent the mean ± SEM of three different experiments, each performed in duplicate. Statistical significance was determined using a one-way ANOVA-Tukey HSD post hoc test: *P < 0.05, **P < 0.01, ***P < 0.001 vs. control; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. cells treated with LPS-TNF-α

Mentions: The effects of the inflammatory damage on the expression of trophic and transcription factors were then determined. LPS-TNF-α treatment significantly increased NF-kB levels (Fig. 5a), consistent with its role as a pro-inflammatory gene [46]. Moreover, mTOR and CREB levels were significantly increased (Fig. 5a). These results are consistent with previous data from LPS or TNF-α-stimulated glial cells [48, 49]. Pre-incubation of astrocytes with TDZ or FLUOX for 24 h further increased inflammation-mediated increase in NF-kB mRNA expression, suggesting that 24-h pre-treatment with antidepressants is not sufficient to reverse the effects of LPS-TNF-α on NF-kB induction. In contrast, a significant decrease in mTOR levels after 24-h TDZ pre-incubation was evidenced (Fig. 5b).Fig. 5


Trazodone regulates neurotrophic/growth factors, mitogen-activated protein kinases and lactate release in human primary astrocytes.

Daniele S, Zappelli E, Martini C - J Neuroinflammation (2015)

Expression of pro-inflammatory genes, trophic and transcription factors in an experimental model of inflammation. a Human astrocytes were treated with 50 μg/ml LPS and 50 ng/ml TNF-α for 24 h. b, c Human astrocytes were treated with medium alone (control), different concentrations of TDZ (100 nM-1 μM), or FLUOX (10 μM) for 24 h (b) or 72 h (c); after drug removal, cells were incubated with 50 μg/ml LPS and 50 ng/ml TNF-α for an additional 24 h. At the end of treatment, total RNA was extracted, and relative mRNA quantification of NF-kB, CREB, mTOR and BDNF was performed by RT-PCR. The data are expressed as fold changes vs. control and represent the mean ± SEM of three different experiments, each performed in duplicate. Statistical significance was determined using a one-way ANOVA-Tukey HSD post hoc test: *P < 0.05, **P < 0.01, ***P < 0.001 vs. control; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. cells treated with LPS-TNF-α
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4666178&req=5

Fig5: Expression of pro-inflammatory genes, trophic and transcription factors in an experimental model of inflammation. a Human astrocytes were treated with 50 μg/ml LPS and 50 ng/ml TNF-α for 24 h. b, c Human astrocytes were treated with medium alone (control), different concentrations of TDZ (100 nM-1 μM), or FLUOX (10 μM) for 24 h (b) or 72 h (c); after drug removal, cells were incubated with 50 μg/ml LPS and 50 ng/ml TNF-α for an additional 24 h. At the end of treatment, total RNA was extracted, and relative mRNA quantification of NF-kB, CREB, mTOR and BDNF was performed by RT-PCR. The data are expressed as fold changes vs. control and represent the mean ± SEM of three different experiments, each performed in duplicate. Statistical significance was determined using a one-way ANOVA-Tukey HSD post hoc test: *P < 0.05, **P < 0.01, ***P < 0.001 vs. control; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. cells treated with LPS-TNF-α
Mentions: The effects of the inflammatory damage on the expression of trophic and transcription factors were then determined. LPS-TNF-α treatment significantly increased NF-kB levels (Fig. 5a), consistent with its role as a pro-inflammatory gene [46]. Moreover, mTOR and CREB levels were significantly increased (Fig. 5a). These results are consistent with previous data from LPS or TNF-α-stimulated glial cells [48, 49]. Pre-incubation of astrocytes with TDZ or FLUOX for 24 h further increased inflammation-mediated increase in NF-kB mRNA expression, suggesting that 24-h pre-treatment with antidepressants is not sufficient to reverse the effects of LPS-TNF-α on NF-kB induction. In contrast, a significant decrease in mTOR levels after 24-h TDZ pre-incubation was evidenced (Fig. 5b).Fig. 5

Bottom Line: TDZ had no effect on cell proliferation, but it decreased pro-inflammatory mediator release and modulated trophic and transcription factor mRNA expression.These effects mainly involved an activation of 5-HT1A and an antagonism at 5-HT2A/C serotonin receptors.Fluoxetine, used in parallel, showed similar final effects nevertheless it activates different receptors/intracellular pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, Pisa, 56126, PI, Italy. simona.daniele@for.unipi.it.

ABSTRACT

Background: In the central nervous system, glial cells provide metabolic and trophic support to neurons and respond to protracted stress and insults by up-regulating inflammatory processes. Reactive astrocytes and microglia are associated with the pathophysiology of neuronal injury, neurodegenerative diseases and major depression, in both animal models and human brains. Several studies have reported clear anti-inflammatory effects of anti-depressant treatment on astrocytes, especially in models of neurological disorders. Trazodone (TDZ) is a triazolopyridine derivative that is structurally unrelated to other major classes of antidepressants. Although the molecular mechanisms of TDZ in neurons have been investigated, it is unclear whether astrocytes are also a TDZ target.

Methods: The effects of TDZ on human astrocytes were investigated in physiological conditions and following inflammatory insult with lipopolysaccharide (LPS) and tumour necrosis factor-α (TNF-α). Astrocytes were assessed for their responses to pro-inflammatory mediators and cytokines, and the receptors and signalling pathways involved in TDZ-mediated effects were evaluated.

Results: TDZ had no effect on cell proliferation, but it decreased pro-inflammatory mediator release and modulated trophic and transcription factor mRNA expression. Following TDZ treatment, the AKT pathway was activated, whereas extracellular signal-regulated kinase and c-Jun NH2-terminal kinase were inhibited. Most importantly, a 72-h TDZ pre-treatment before inflammatory insult completely reversed the anti-proliferative effects induced by LPS-TNF-α. The expression or the activity of inflammatory mediators, including interleukin-6, c-Jun NH2-terminal kinase and nuclear factor κB, were also reduced. Furthermore, TDZ affected astrocyte metabolic support to neurons by counteracting the inflammation-mediated lactate decrease. Finally, TDZ protected neuronal-like cells against neurotoxicity mediated by activated astrocytes. These effects mainly involved an activation of 5-HT1A and an antagonism at 5-HT2A/C serotonin receptors. Fluoxetine, used in parallel, showed similar final effects nevertheless it activates different receptors/intracellular pathways.

Conclusions: Altogether, our results demonstrated that TDZ directly acts on astrocytes by regulating intracellular signalling pathways and increasing specific astrocyte-derived neurotrophic factor expression and lactate release. TDZ may contribute to neuronal support by normalizing trophic and metabolic support during neuroinflammation, which is associated with neurological diseases, including major depression.

No MeSH data available.


Related in: MedlinePlus