Insulin increases glutamate transporter GLT1 in cultured astrocytes

Biochem Biophys Res Commun. 2011 Feb 25;405(4):691-6. doi: 10.1016/j.bbrc.2011.01.105. Epub 2011 Feb 1.

Abstract

The astroglial cell-specific glutamate transporter subtype 2 (excitatory amino acid transporter 2, GLT1) plays an important role in excitotoxicity that develops after damage to the central nervous system (CNS) is incurred. Both the protein kinase C signaling pathway and the epidermal growth factor (EGF) pathway have been suggested to participate in the modulation of GLT1, but the modulatory mechanisms of GLT1 expression are not fully understood. In the present study, we aimed to evaluate the effects of insulin on GLT1 expression. We found that short-term stimulation of insulin led to the upregulation of both total and surface expressions of GLT1. Akt phosphorylation increased after insulin treatment, and triciribine, the inhibitor of Akt phosphorylation, significantly inhibited the effects of insulin. We also found that the upregulation of GLT1 expression correlated with increased kappa B motif-binding phosphoprotein (KBBP) and GLT1 mRNA levels. Our results suggest that insulin may modulate the expression of astrocytic GLT1, which might play a role in reactive astrocytes after CNS injuries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / drug effects*
  • Astrocytes / metabolism
  • Excitatory Amino Acid Transporter 2 / biosynthesis*
  • Excitatory Amino Acid Transporter 2 / genetics
  • Insulin / pharmacology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Rats
  • Rats, Sprague-Dawley
  • Up-Regulation

Substances

  • Excitatory Amino Acid Transporter 2
  • Insulin
  • RNA, Messenger
  • Slc1a2 protein, rat
  • Proto-Oncogene Proteins c-akt