Neuroprotective effects of intrastriatal injection of rapamycin in a mouse model of excitotoxicity induced by quinolinic acid

Soraya Wilke Saliba, Erica Leandro Marciano Vieira, Rebeca Priscila de Melo Santos, Eduardo Candelario-Jalil, Bernd L. Fiebich, Luciene Bruno Vieira, Antonio Lucio Teixeira, Antonio Carlos Pinheiro de Oliveira

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Background: The mammalian target of rapamycin (mTOR) is a kinase involved in a variety of physiological and pathological functions. However, the exact role of mTOR in excitotoxicity is poorly understood. Here, we investigated the effects of mTOR inhibition with rapamycin against neurodegeneration, and motor impairment, as well as inflammatory profile caused by an excitotoxic stimulus. Methods: A single and unilateral striatal injection of quinolinic acid (QA) was used to induce excitotoxicity in mice. Rapamycin (250 nL of 0.2, 2, or 20 μM; intrastriatal route) was administered 15 min before QA injection. Forty-eight hours after QA administration, rotarod test was performed to evaluate motor coordination and balance. Fluoro-Jade C, Iba-1, and GFAP staining were used to evaluate neuronal cell death, microglia morphology, and astrocytes density, respectively, at this time point. Levels of cytokines and neurotrophic factors were measured by ELISA and Cytometric Bead Array 8 h after QA injection. Striatal synaptosomes were used to evaluate the release of glutamate. Results: We first demonstrated that rapamycin prevented the motor impairment induced by QA. Moreover, mTOR inhibition also reduced the neurodegeneration and the production of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α induced by excitotoxic stimulus. The lowest dose of rapamycin also increased the production of IL-10 and prevented the reduction of astrocyte density induced by QA. By using an in vitro approach, we demonstrated that rapamycin differently alters the release of glutamate from striatal synaptosomes induced by QA, reducing or enhancing the release of this neurotransmitter at low or high concentrations, respectively. Conclusion: Taken together, these data demonstrated a protective effect of rapamycin against an excitotoxic stimulus. Therefore, this study provides new evidence of the detrimental role of mTOR in neurodegeneration, which might represent an important target for the treatment of neurodegenerative diseases.

Original languageEnglish (US)
Article number25
JournalJournal of Neuroinflammation
Volume14
Issue number1
DOIs
StatePublished - Jan 31 2017
Externally publishedYes

Keywords

  • Glutamate
  • Inflammation
  • MTOR
  • Neurodegeneration
  • Neurotrophic factors
  • Quinolinic acid
  • Rapamycin

ASJC Scopus subject areas

  • General Neuroscience
  • Immunology
  • Neurology
  • Cellular and Molecular Neuroscience

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