Expression of a Constitutively Active Human Insulin Receptor in Hippocampal Neurons Does Not Alter VGCC Currents

H. N. Frazier, K. L. Anderson, S. Maimaiti, A. O. Ghoweri, S. D. Kraner, G. J. Popa, K. K. Hampton, M. D. Mendenhall, C. M. Norris, R. J. Craven, O. Thibault

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Memory and cognitive decline are the product of numerous physiological changes within the aging brain. Multiple theories have focused on the oxidative, calcium, cholinergic, vascular, and inflammation hypotheses of brain aging, with recent evidence suggesting that reductions in insulin signaling may also contribute. Specifically, a reduction in insulin receptor density and mRNA levels has been implicated, however, overcoming these changes remains a challenge. While increasing insulin receptor occupation has been successful in offsetting cognitive decline, alternative molecular approaches should be considered as they could bypass the need for brain insulin delivery. Moreover, this approach may be favorable to test the impact of continued insulin receptor signaling on neuronal function. Here we used hippocampal cultures infected with lentivirus with or without IRβ, a constitutively active, truncated form of the human insulin receptor, to characterize the impact continued insulin receptor signaling on voltage-gated calcium channels. Infected cultures were harvested between DIV 13 and 17 (48 h after infection) for Western blot analysis on pAKT and AKT. These results were complemented with whole-cell patch-clamp recordings of individual pyramidal neurons starting 96 h post-infection. Results indicate that while a significant increase in neuronal pAKT/AKT ratio was seen at the time point tested, effects on voltage-gated calcium channels were not detected. These results suggest that there is a significant difference between constitutively active insulin receptors and the actions of insulin on an intact receptor, highlighting potential alternate mechanisms of neuronal insulin resistance and mode of activation.

Original languageEnglish
Pages (from-to)269-280
Number of pages12
JournalNeurochemical Research
Volume44
Issue number1
DOIs
StatePublished - Jan 15 2019

Bibliographical note

Funding Information:
Acknowledgements We acknowledge the National Institute of Health for sources of funding for these experiments: Thibault, O. (R01AG033649); Frazier, H. and Hampton, K.K. (T32DK007778). The authors acknowledge the use of facilities in the University of Kentucky Center for Molecular Medicine Genetic Technologies Core. This core is supported in part by National Institute of Health Grant Number P30GM110787.

Funding Information:
We acknowledge the National Institute of Health for sources of funding for these experiments: Thibault, O. (R01AG033649); Frazier, H.?and Hampton, K.K. (T32DK007778). The authors acknowledge the use of facilities in the University of Kentucky Center for Molecular Medicine Genetic Technologies Core. This core is supported in part by National Institute of Health Grant Number P30GM110787.

Publisher Copyright:
© 2018, Springer Science+Business Media, LLC, part of Springer Nature.

Keywords

  • Calcium
  • Electrophysiology
  • Insulin resistance
  • Memory

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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