Changes in Cathepsin D and Beclin-1 mRNA and protein expression by the excitotoxin quinolinic acid in human astrocytes and neurons

Nady Braidy, Bruce J. Brew, Nibaldo C. Inestrosa, Roger Chung, Perminder Sachdev, Gilles J. Guillemin

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Quinolinic acid (QUIN) is an excitotoxin that has been implicated in the pathogenesis of several neurodegenerative diseases including Alzheimer's disease (AD). While QUIN has been shown to induce neuronal and astrocytic apoptosis as well as excitotoxic cell death, other mechanisms such as autophagy remain unexplored. We investigated the role of Cathepsin D (CatD) and Beclin-1 (Bc1) in QUIN-treated primary human astrocytes and neurons. We demonstrated that the expression patterns of CatD, a lysosomal aspartic protease associated with autophagy, are increased at 24 h after QUIN treatment. However, unlike CatD, the expression patterns of Bc1, a tumour suppressor protein, are significantly reduced at 24 h after QUIN treatment in both brain cell types. Furthermore, we showed that the NMDA ion channel blockers, MK801, can attenuate QUIN-induced changes CatD and Bc1 expression in both astrocytes and neurons. Taken together, these results suggest that induction of deficits in CatD and Bc1 is a significant mechanism for QUIN toxicity in glial and neuronal cells. Maintenance of autophagy may play a crucial role in neuroprotection in the setting of AD.

Original languageEnglish
Pages (from-to)873-883
Number of pages11
JournalMetabolic brain disease
Volume29
Issue number3
DOIs
Publication statusPublished - 1 Sep 2014

Keywords

  • excitotoxicity
  • Quinolinic acid
  • autophagy
  • Cathepsin D
  • astrocytes

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