PCB-95 modulates the calcium-dependent signaling pathway responsible for activity-dependent dendritic growth

Gary A. Wayman, Diptiman D. Bose, Dongren Yang, Adam Lesiak, Donald Bruun, Soren Impey, Veronica Ledoux, Isaac N Pessah, Pamela J Lein

Research output: Contribution to journalArticle

73 Scopus citations

Abstract

Background: Non-dioxin-like (NDL) polychlorinated biphenyls (PCBs) promote dendritic growth in hippocampal neurons via ryanodine receptor (RyR)-dependent mechanisms; however, downstream signaling events that link enhanced RyR activity to dendritic growth are unknown. Activity-dependent dendritic growth, which is a critical determinant of neuronal connectivity in the developing brain, is mediated by calcium ion (Ca2++)-dependent activation of Ca2++/calmodulin kinase-I (CaMKI), which triggers cAMP response element binding protein (CREB)-dependent Wnt2 transcription. RyRs regulate the spatiotemporal dynamics of intracellular Ca2++ signals, but whether RyRs promote dendritic growth via modulation of this signaling pathway is not known. Objective: We tested the hypothesis that the CaMKI-CREB-Wnt2 signaling pathway couples NDL PCB-enhanced RyR activity to dendritic arborization. Methods and Results: Ca2++ imaging of dissociated cultures of primary rat hippocampal neurons indicated that PCB-95 (2,2 ́,3,5 ́6-pentachlorobiphenyl; a potent RyR potentiator), enhanced synchronized Ca2++ oscillations in somata and dendrites that were blocked by ryanodine. As determined by Western blotting and quantitative polymerase chain reaction, PCB-95 also activated CREB and up-regulated Wnt2. Blocking CaMKK, CaMKIα/γ, MEK/ERK, CREB, or Wnt2 prevented PCB-95-induced dendritic growth. Antagonism of γ-aminobutyric acid (GABA) receptors with bicuculline (BIC) phenocopied the dendrite-promoting effects of PCB-95, and pharmacological antagonism or siRNA knockdown of RyR blocked BIC-induced dendritic growth in dissociated and slice cultures of hippocampal neurons. Conclusions: RyR activity contributes to dynamic remodeling of dendritic architecture in response to NDL PCBs via CaMKI-CREB-Wnt2 signaling in rats. Our findings identify PCBs as candidate environmental risk factors for neurodevelopmental disorders, especially in children with heritable deficits in calcium signaling associated with autism.

Original languageEnglish (US)
Pages (from-to)1003-1009
Number of pages7
JournalEnvironmental Health Perspectives
Volume120
Issue number7
DOIs
StatePublished - Jun 2012

Keywords

  • Ca
  • CaMKI
  • CREB
  • Dendrites
  • Developmental neurotoxicity
  • Hippocampal MEK
  • Neuronal connectivity
  • Neurons
  • Non-dioxin-like PCBs
  • Ryanodine receptor
  • Utism
  • Wnt2

ASJC Scopus subject areas

  • Health, Toxicology and Mutagenesis
  • Public Health, Environmental and Occupational Health

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