Vitamin E inhibits activated chaperone-mediated autophagy in rats with status epilepticus

Neuroscience. 2009 Jun 16;161(1):73-7. doi: 10.1016/j.neuroscience.2009.02.059. Epub 2009 Mar 9.

Abstract

Seizures and status epilepticus induce an excessive production of reactive oxygen species leading to oxidative stress. Vitamin E, a classic antioxidant, has a neuroprotective effect on rats with seizures by regulating reactive oxygen species production. The activity of chaperone-mediated autophagy, a selective pathway for the degradation of cytosolic proteins in lysosomes, is enhanced during oxidative stress. Whether chaperone-mediated autophagy is induced during status epilepticus is not established. To address this problem, we used pilocarpine to elicit status epilepticus in rats. Lysosome-associated membrane protein 2a was used to estimate chaperone-mediated autophagy. We showed that compared to control animals, lysosome-associated membrane protein 2a at lysosomal membranes increased significantly in rats at 8 h, 16 h, and 24 h after induction of status epilepticus, which directly correlated with chaperone-mediated autophagy activity. Since reactive oxygen species are believed to be important in the pathogenesis of status epilepticus and are essential for the process of chaperone-mediated autophagy, we also sought to determine if pretreatment with vitamin E reduced chaperone-mediated autophagy. Pretreatment with vitamin E reduced oxidative stress and partially inhibited chaperone-mediated autophagy in brain at 24 h after status epilepticus versus vehicle. Taken together, these data show that chaperone-mediated autophagy is increased in rats with pilocarpine-induced status epilepticus through upregulation of de novo synthesis of lysosome-associated membrane protein 2a. Antioxidants such as vitamin E may partially inhibit activated chaperone-mediated autophagy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology*
  • Autophagy / drug effects*
  • Hippocampus / metabolism
  • Lysosomal-Associated Membrane Protein 2 / biosynthesis*
  • Male
  • Molecular Chaperones / biosynthesis*
  • Oxidative Stress
  • Pilocarpine
  • RNA, Messenger / biosynthesis
  • Rats
  • Rats, Wistar
  • Status Epilepticus / chemically induced
  • Status Epilepticus / metabolism*
  • Status Epilepticus / pathology
  • Up-Regulation
  • Vitamin E / pharmacology*

Substances

  • Antioxidants
  • Lysosomal-Associated Membrane Protein 2
  • Molecular Chaperones
  • RNA, Messenger
  • Pilocarpine
  • Vitamin E