Proteasome inhibitor lactacystin disturbs the intracellular calcium homeostasis of dopamine neurons in ventral mesencephalic cultures

Xuping Li, Dehua Yang, Liang Li, Changgeng Peng, Shen Chen, Weidong Le

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Ubiquitin proteasome system (UPS) impairment has been implicated in the pathology of Parkinson's disease, but the mechanisms underlying the UPS impairment-induced dopamine (DA) neuron degeneration remain obscure. To test whether calcium homeostasis disturbance is involved in the DA neuronal injury resulting from UPS impairment, we treated the primary ventral mesencephalic (VM) cultures with the proteasome inhibitor lactacystin, and observed its effects on the expression of the gene Homer 1a that is related to calcium homeostasis, and the intracellular free calcium ([Ca2+]i) levels as well as the DA neuron survival. We also investigated a possible role of the L-type voltage dependent calcium channels (L-VDCC) in these events. We found that the lactacystin exposure induced the Homer 1a expression, lowered the [Ca2+]i levels, reduced the depolarization-induced calcium entry and DA release in the VM cultures, and caused a significant DA neuron loss. Activation of L-VDCC by potassium chloride or its agonists alleviated the effects of lactacystin on the [Ca2+]i levels and promoted DA neuron survival, whereas L-VDCC antagonists blocked the depolarization-mediated neuroprotective effect, and at high concentrations the L-VDCC antagonists aggravated the lactacystin-induced DA neuronal injury. These results indicate that calcium homeostasis disturbance may be a novel pathological mechanism leading to DA neuronal injury under conditions of proteasome inhibition.

Original languageEnglish (US)
Pages (from-to)959-965
Number of pages7
JournalNeurochemistry International
Volume50
Issue number7-8
DOIs
StatePublished - Jun 2007

Keywords

  • Calcium homeostasis
  • Dopamine neuronal injury
  • L-type voltage dependent calcium channels
  • Lactacystin
  • Ubiquitin-proteasome system

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Cellular and Molecular Neuroscience

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