Abstract
Bilirubin is neurotoxic upon excess accumulation in the brain, but it also plays important physiological roles related to its antioxidant properties. Here we report that exposure of PC12 and primary rat cerebellar granule neurons to bilirubin (0.5-10 μM) drastically decreases nerve growth factor (NGF)/brain-derived neurotrophic factor signaling to Akt and extracellular signal-regulated kinases (ERKs), indicating a direct interference of the molecule with crucial prosurvival signaling pathways. This effect likely involves the scavenging capacity of bilirubin, the latter being able to inhibit, in PC12 cells, accumulation of intracellular reactive oxygen species and phosphorylation of Akt and ERKs in response to extracellular hydrogen peroxide. Interestingly, in the absence of exogenous growth factor, bilirubin elicited the phosphorylation of ERKs and of the cAMP responsive element binding (CREB) transcription factor, a signature of NGF-dependent survival signaling. These growth factor-like signaling effects were paralleled by the induction of the neuronal nitric oxide synthase (nNOS) and generation of nitric oxide (NO). Pharmacological dissection of the signaling cascade triggered by bilirubin revealed that phosphorylation of ERKs requires NO signaling through soluble guanylyl cyclase, and, further upstream, influx of extracellular calcium is necessary for nNOS induction and NO release, likely through calcium-dependent phosphorylation of CREB. Importantly, the cascade elicited by bilirubin through NO and ERK is cytoprotective, as revealed by exacerbated bilirubin toxicity in cultures treated by either NOS or MEK inhibitors. Taken together, these observations indicate an important action of bilirubin on redox signaling by neurotrophins, with either inhibitory or agonistic effects based on growth factor availability.
| Original language | English |
|---|---|
| Pages (from-to) | 2235-2249 |
| Number of pages | 15 |
| Journal | Journal of Neuroscience Research |
| Volume | 86 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - Aug 1 2008 |
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Keywords
- CREB
- Heme oxygenase
- Nitric oxide
- ROS
ASJC Scopus subject areas
- Neuroscience(all)
Cite this
Bilirubin as an endogenous modulator of neurotrophin redox signaling. / Mancuso, Cesare; Capone, Caterina; Ranieri, Sofia Chiatamone; Fusco, Salvatore; Calabrese, Vittorio; Eboli, Maria Luisa; Preziosi, Paolo; Galeotti, Tommaso; Pani, Giovambattista.
In: Journal of Neuroscience Research, Vol. 86, No. 10, 01.08.2008, p. 2235-2249.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Bilirubin as an endogenous modulator of neurotrophin redox signaling
AU - Mancuso, Cesare
AU - Capone, Caterina
AU - Ranieri, Sofia Chiatamone
AU - Fusco, Salvatore
AU - Calabrese, Vittorio
AU - Eboli, Maria Luisa
AU - Preziosi, Paolo
AU - Galeotti, Tommaso
AU - Pani, Giovambattista
PY - 2008/8/1
Y1 - 2008/8/1
N2 - Bilirubin is neurotoxic upon excess accumulation in the brain, but it also plays important physiological roles related to its antioxidant properties. Here we report that exposure of PC12 and primary rat cerebellar granule neurons to bilirubin (0.5-10 μM) drastically decreases nerve growth factor (NGF)/brain-derived neurotrophic factor signaling to Akt and extracellular signal-regulated kinases (ERKs), indicating a direct interference of the molecule with crucial prosurvival signaling pathways. This effect likely involves the scavenging capacity of bilirubin, the latter being able to inhibit, in PC12 cells, accumulation of intracellular reactive oxygen species and phosphorylation of Akt and ERKs in response to extracellular hydrogen peroxide. Interestingly, in the absence of exogenous growth factor, bilirubin elicited the phosphorylation of ERKs and of the cAMP responsive element binding (CREB) transcription factor, a signature of NGF-dependent survival signaling. These growth factor-like signaling effects were paralleled by the induction of the neuronal nitric oxide synthase (nNOS) and generation of nitric oxide (NO). Pharmacological dissection of the signaling cascade triggered by bilirubin revealed that phosphorylation of ERKs requires NO signaling through soluble guanylyl cyclase, and, further upstream, influx of extracellular calcium is necessary for nNOS induction and NO release, likely through calcium-dependent phosphorylation of CREB. Importantly, the cascade elicited by bilirubin through NO and ERK is cytoprotective, as revealed by exacerbated bilirubin toxicity in cultures treated by either NOS or MEK inhibitors. Taken together, these observations indicate an important action of bilirubin on redox signaling by neurotrophins, with either inhibitory or agonistic effects based on growth factor availability.
AB - Bilirubin is neurotoxic upon excess accumulation in the brain, but it also plays important physiological roles related to its antioxidant properties. Here we report that exposure of PC12 and primary rat cerebellar granule neurons to bilirubin (0.5-10 μM) drastically decreases nerve growth factor (NGF)/brain-derived neurotrophic factor signaling to Akt and extracellular signal-regulated kinases (ERKs), indicating a direct interference of the molecule with crucial prosurvival signaling pathways. This effect likely involves the scavenging capacity of bilirubin, the latter being able to inhibit, in PC12 cells, accumulation of intracellular reactive oxygen species and phosphorylation of Akt and ERKs in response to extracellular hydrogen peroxide. Interestingly, in the absence of exogenous growth factor, bilirubin elicited the phosphorylation of ERKs and of the cAMP responsive element binding (CREB) transcription factor, a signature of NGF-dependent survival signaling. These growth factor-like signaling effects were paralleled by the induction of the neuronal nitric oxide synthase (nNOS) and generation of nitric oxide (NO). Pharmacological dissection of the signaling cascade triggered by bilirubin revealed that phosphorylation of ERKs requires NO signaling through soluble guanylyl cyclase, and, further upstream, influx of extracellular calcium is necessary for nNOS induction and NO release, likely through calcium-dependent phosphorylation of CREB. Importantly, the cascade elicited by bilirubin through NO and ERK is cytoprotective, as revealed by exacerbated bilirubin toxicity in cultures treated by either NOS or MEK inhibitors. Taken together, these observations indicate an important action of bilirubin on redox signaling by neurotrophins, with either inhibitory or agonistic effects based on growth factor availability.
KW - CREB
KW - Heme oxygenase
KW - Nitric oxide
KW - ROS
UR - http://www.scopus.com/inward/record.url?scp=48249127222&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=48249127222&partnerID=8YFLogxK
U2 - 10.1002/jnr.21665
DO - 10.1002/jnr.21665
M3 - Article
C2 - 18338802
AN - SCOPUS:48249127222
VL - 86
SP - 2235
EP - 2249
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
SN - 0360-4012
IS - 10
ER -