Choline supplementation mitigates effects of bilirubin in cerebellar granule neurons in vitro
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Published on: May 10, 2017
Mrinaj Janampalli1, Spencer T Kitchen1, Sergei Vatolin1
1Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
Insights
Choline supplementation protects premature infants from bilirubin neurotoxicity by improving L1 signaling and function. This intervention enhances neural resilience against bilirubin
Area of Science:
- Neuroscience
- Biochemistry
- Developmental Biology
Background:
- Premature infants face risks of bilirubin-induced neurotoxicity.
- Bilirubin disrupts L1 cell adhesion molecule signaling, affecting neuronal development.
- Bilirubin alters L1 distribution in lipid rafts and impairs neurite outgrowth.
Purpose of the Study:
- To investigate the protective effects of choline on L1 signaling and function in the context of bilirubin exposure.
- To determine if choline supplementation can mitigate bilirubin's neurotoxic effects on cerebellar granule neurons (CGN).
Main Methods:
- Cultured CGN with and without choline supplementation in the presence of bilirubin.
- Assessed L1 activation of ERK1/2, L1 phosphorylation/dephosphorylation.
- Quantified L1 distribution in lipid rafts and measured CGN neurite outgrowth.
Main Results:
- Choline significantly reduced bilirubin's impact on L1/ERK1/2 signaling by 220%.
- Choline increased L1 phosphorylation and dephosphorylation by 34% and 35% respectively.
- Choline ameliorated L1 redistribution in lipid rafts by 38% and increased neurite length by 11%.
Conclusions:
- Choline pretreatment effectively counteracted bilirubin's disruption of L1 function in CGN.
- Choline supplementation may enhance infant resilience to bilirubin's neurotoxic effects.
- This study establishes choline as a potential intervention for bilirubin neurotoxicity.
Background:
Premature infants may suffer from high levels of bilirubin that could lead to neurotoxicity. Bilirubin has been shown to decrease L1-mediated ERK1/2 signaling, L1 phosphorylation, and L1 tyrosine 1176 dephosphorylation. Furthermore, bilirubin redistributes L1 into lipid rafts (LR) and decreases L1-mediated neurite outgrowth. We demonstrate that choline supplementation improves L1 function and signaling in the presence of bilirubin.
Methods:
Cerebellar granule neurons (CGN) were cultured with and without supplemental choline, and the effects on L1 signaling and function were measured in the presence of bilirubin. L1 activation of ERK1/2, L1 phosphorylation and dephosphorylation were measured. L1 distribution in LR was quantified and neurite outgrowth of CGN was determined.
Results:
Forty µM choline significantly reduced the effect of bilirubin on L1 activation of ERK1/2 by 220% (p = 0.04), and increased L1 triggered changes in tyrosine phosphorylation /dephosphorylation of L1 by 34% (p = 0.026) and 35% (p = 0.02) respectively. Choline ameliorated the redistribution of L1 in lipid rafts by 38% (p = 0.02) and increased L1-mediated mean neurite length by 11% (p = 0.04).
Conclusion:
Choline pretreatment of CGN significantly reduced the disruption of L1 function by bilirubin. The supplementation of pregnant women and preterm infants with choline may increase infant resilience to the effects of bilirubin.
Impact:
This article establishes choline as an intervention for the neurotoxic effects of bilirubin on lipid rafts. This article provides clear evidence toward establishing one intervention for bilirubin neurotoxicity, where little is understood. This article paves the way for future investigation into the mechanism of the ameliorative effect of choline on bilirubin neurotoxicity.
