Insulin expression in cultured astrocytes and the decrease by amyloid β

Katsura Takano, Keisuke Koarashi, Kenji Kawabe, Masanori Itakura, Hidemitsu Nakajima, Mitsuaki Moriyama, Yoichi Nakamura

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Insulin resistance in brain has been reported in Alzheimer's diseases (AD). Insulin signaling is important for homeostasis in brain function and reported to be disturbed in neurons leading to tau phosphorylation and neurofibrillary tangles. Many investigations of insulin in neurons have been reported; however, it has not been reported whether astrocytes also produce insulin. In the present study, we assessed the expression of insulin in astrocytes cultured from rat embryonic brain and the effects of amyloid β1-42 (Aβ) and lipopolysaccharide (LPS) on the expression. We found that astrocytes expressed preproinsulin mRNAs and insulin protein, and that Aβ or LPS decreased these expressions. Antioxidants, glutathione and N-acetylcysteine, restored the decreases in insulin mRNA expression by Aβ and by LPS. Insulin protein was detected in astrocyte conditioned medium. These results suggest that astrocytes express and secrete insulin. Oxidative stress might be involved in the decreased insulin expression by Aβ or LPS. The insulin decrease by Aβ in astrocytes could be a novel disturbing mechanism for brain insulin signaling in AD.

Original languageEnglish
JournalNeurochemistry International
DOIs
Publication statusAccepted/In press - Jan 1 2017
Externally publishedYes

Keywords

  • Amyloid β
  • Astrocytes
  • Insulin
  • Reactive oxygen species

ASJC Scopus subject areas

  • Cellular and Molecular Neuroscience
  • Cell Biology

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    Takano, K., Koarashi, K., Kawabe, K., Itakura, M., Nakajima, H., Moriyama, M., & Nakamura, Y. (Accepted/In press). Insulin expression in cultured astrocytes and the decrease by amyloid β. Neurochemistry International. https://doi.org/10.1016/j.neuint.2017.10.017