Signal transduction in astrocytes: Localization and release of inorganic polyphosphate

Plamena R. Angelova, Kathrine Z. Iversen, Anja G. Teschemacher, Sergey Kasparov, Alexander V. Gourine*, Andrey Y. Abramov

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)
211 Downloads (Pure)

Abstract

Inorganic polyphosphate (polyP) is present in every cell and is highly conserved from primeval times. In the mammalian cells, polyP plays multiple roles including control of cell bioenergetics and signal transduction. In the brain, polyP mediates signaling between astrocytes via activation of purinergic receptors, however, the mechanisms of polyP release remain unknown. Here we report identification of polyP-containing vesicles in cortical astrocytes and the main triggers that evoke vesicular polyP release. In cultured astrocytes, polyP was localized predominantly within the intracellular vesicular compartments which express vesicular nucleotide transporter VNUT (putative ATP-containing vesicles), but not within the compartments expressing vesicular glutamate transporter 2 (VGLUT2). The number of lysosomes which contain polyP was dependent on the conditions of astrocytes. Release of polyP from a proportion of lysosomes could be induced by calcium ionophores. In contrast, polyP release from the VNUT-containing vesicles could be triggered by various physiological stimuli, such as pH changes, polyP induced polyP release and other stimuli which increase [Ca2+]i. These data suggest that astrocytes release polyP predominantly via exocytosis from the VNUT-containing vesicles.

Original languageEnglish
Pages (from-to)2126-2136
Number of pages10
JournalGlia
Volume66
Issue number10
Early online date7 Sep 2018
DOIs
Publication statusPublished - 1 Oct 2018

Keywords

  • astrocytes
  • inorganic polyphosphate
  • lysosomes
  • mitochondria
  • VNUT

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