Anatomical localization of protease-activated receptor-1 and protease-mediated neuroglilal crosstalk on peri-synaptic astrocytic endfeet

Efrat Shavit, Daniel M. Michaelson, Joab Chapman

Research output: Contribution to journalArticlepeer-review

Abstract

We studied the localization, activation and function of protease-activated receptor 1 (PAR-1) at the CNS synapse utilizing rat brain synaptosomes and slices. Confocal immunofluoresence and transmission electron microscopy in brain slices with pre-embedding diaminobenzidine (DAB) immunostaining found PAR-1 predominantly localized to the peri-synaptic astrocytic endfeet. Structural confocal immunofluorescence microscopy studies of isolated synaptosomes revealed spherical structures stained with anti-PAR-1 antibody which co-stained mainly for glial-filament acidic protein compared with the neuronal markers synaptophysin and PSD-95. Immunoblot studies of synaptosomes demonstrated an appropriate major band corresponding to PAR-1 and activation of the receptor by a specific agonist peptide (SFLLRN) significantly modulated phosphorylated extracellular signal-regulated kinase. A significant membrane potential depolarization was produced by thrombin (1 U/mL) and the PAR-1 agonist (100 μM) and depolarization by high K + elevated extracellular thrombin-like activity in the synaptosomes preparation. The results indicate PAR-1 localized to the peri-synaptic astrocytic endfeet is most likely activated by synaptic proteases and induces cellular signaling and modulation of synaptic electrophysiology. A protease mediated neuron-glia pathway may be important in both physiological and pathological regulation of the synapse.

Original languageEnglish
Pages (from-to)460-473
Number of pages14
JournalJournal of Neurochemistry
Volume119
Issue number3
DOIs
StatePublished - Nov 2011

Keywords

  • astrocytic endfeet
  • glia
  • protease-activated receptors
  • synapse
  • synaptosome
  • thrombin

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