Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death

Lu Cao, Mary P. Walker, Naveen K. Vaidya, Mingui Fu, Santosh Kumar, Anil Kumar

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy, generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6-h exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7, and p-Bcl-2/Beclin-1 were also involved, and this was confirmed by using selective inhibitors and small interfering RNAs (siRNAs). In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death.

Original languageEnglish (US)
Pages (from-to)4417-4430
Number of pages14
JournalMolecular Neurobiology
Volume53
Issue number7
DOIs
StatePublished - Sep 1 2016

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Autophagy
Phosphatidylinositol 3-Kinases
Cocaine
Astrocytes
TOR Serine-Threonine Kinases
Beclin-1
sigma-1 receptor
Street Drugs
Transmission Electron Microscopy
Confocal Microscopy
Caspase 3
Small Interfering RNA
Cell Death

All Science Journal Classification (ASJC) codes

  • Neuroscience (miscellaneous)
  • Neurology
  • Cellular and Molecular Neuroscience

Cite this

Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death. / Cao, Lu; Walker, Mary P.; Vaidya, Naveen K.; Fu, Mingui; Kumar, Santosh; Kumar, Anil.

In: Molecular Neurobiology, Vol. 53, No. 7, 01.09.2016, p. 4417-4430.

Research output: Contribution to journalArticle

Cao, Lu ; Walker, Mary P. ; Vaidya, Naveen K. ; Fu, Mingui ; Kumar, Santosh ; Kumar, Anil. / Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death. In: Molecular Neurobiology. 2016 ; Vol. 53, No. 7. pp. 4417-4430.
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