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Differentiation of the SH-SY5Y Human Neuroblastoma Cell Line
Published on: February 17, 2016
Regulation of FOXO3a by brain-derived neurotrophic factor in differentiated human SH-SY5Y neuroblastoma cells
Wawa Zhu1, Gautam N Bijur, Nathan A Styles
1Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, 1075 Sparks Center, 1720 7th Avenue South Birmingham, AL 35294-0017, USA.
Abstract:
FOXO3a is a ubiquitously expressed mammalian forkhead transcription factor with a high expression level in adult brain. The activity of FOXO3a is inhibited by growth factors through activation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling, which phosphorylates FOXO3a and decreases the level of FOXO3a in the nucleus. In the present study, we examined the regulation of FOXO3a by brain-derived neurotrophic factor (BDNF) in retinoic acid (RA)-differentiated human SH-SY5Y neuroblastoma cells. BDNF caused a rapid and time-dependent decrease of nuclear FOXO3a with a corresponding increase of cytosolic FOXO3a. The rate of the BDNF-induced nuclear/cytosolic redistribution was consistent with the time course of BDNF-induced threonine32-phosphorylation of FOXO3a, and was mediated by the PI3K/Akt signaling pathway. Active FOXO3a rapidly increased the level of Bcl-2-interacting mediator (bim) in differentiated SH-SY5Y cells, and BDNF decreased the FOXO3a-induced increase of bim through activation of both PI3K/Akt and Erk signaling pathways. Thapsigargin, an endoplasmic reticulum (ER) stress-inducing agent, significantly decreased threonine32-phosphorylation of FOXO3a, and increased nuclear and decreased cytosolic FOXO3a, suggesting that thapsigargin activates FOXO3a. Treatment with BDNF completely reversed and blocked the thapsigargin-induced dephosphorylation and nuclear accumulation of FOXO3a. In addition, protein phosphatase 1/2A inhibitors increased threonine32-phosphorylation of FOXO3a, decreased nuclear FOXO3a, and blocked thapsigargin-induced activity of FOXO3a. The regulatory effect of BDNF on FOXO3a and its target genes may play a significant role in the BDNF-mediated neuronal survival, differentiation, and plasticity.
Insights
Brain-derived neurotrophic factor (BDNF) regulates the transcription factor FOXO3a activity in neurons via PI3K/Akt signaling. BDNF impacts FOXO3a
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Signaling
Background:
- FOXO3a is a key transcription factor in the brain, regulated by growth factors via PI3K/Akt signaling.
- Phosphorylation by Akt inhibits FOXO3a, reducing its nuclear localization and activity.
Purpose of the Study:
- To investigate how brain-derived neurotrophic factor (BDNF) regulates FOXO3a in differentiated human neuroblastoma cells.
- To elucidate the signaling pathways involved in BDNF-mediated FOXO3a regulation.
Main Methods:
- Utilized retinoic acid-differentiated SH-SY5Y neuroblastoma cells.
- Examined FOXO3a localization, phosphorylation, and target gene expression (bim) following BDNF treatment.
- Investigated the roles of PI3K/Akt, Erk signaling, and protein phosphatase 1/2A inhibitors.
Main Results:
- BDNF induced a rapid decrease in nuclear FOXO3a and increase in cytosolic FOXO3a, mediated by PI3K/Akt signaling and FOXO3a phosphorylation at threonine32.
- BDNF counteracted the FOXO3a-activating effects of endoplasmic reticulum stress induced by thapsigargin.
- BDNF modulated the expression of the FOXO3a target gene bim, involving both PI3K/Akt and Erk pathways.
Conclusions:
- BDNF signaling, primarily through PI3K/Akt, controls FOXO3a activity and localization in neuronal cells.
- BDNF's regulation of FOXO3a and its target genes likely contributes to neuronal survival, differentiation, and plasticity.
- Understanding this pathway offers insights into neuroprotective mechanisms and neuronal development.
