Blockade of astrocytic calcineurin/NFAT signaling helps to normalize hippocampal synaptic function and plasticity in a rat model of traumatic brain injury

Jennifer L. Furman, Pradoldej Sompol, Susan D. Kraner, Melanie M. Pleiss, Esther J. Putman, Jacob Dunkerson, Hafiz Mohmmad Abdul, Kelly N. Roberts, Stephen W. Scheff, Christopher M. Norris

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

Increasing evidence suggests that the calcineurin (CN)-dependent transcription factor NFAT (Nuclear Factor of Activated T cells) mediates deleterious effects of astrocytes in progressive neurodegenerative conditions. However, the impact of astrocytic CN/NFAT signaling on neural function/recovery after acute injury has not been investigated extensively. Using a controlled cortical impact (CCI) procedure in rats, we show that traumatic brain injury is associated with an increase in the activities of NFATs 1 and 4 in the hippocampus at 7 d after injury. NFAT4, but not NFAT1, exhibited extensive labeling in astrocytes and was found throughout the axon/dendrite layers of CA1 and the dentate gyrus. Blockade of the astrocytic CN/NFAT pathway in rats using adeno-associated virus (AAV) vectors expressing the astrocyte-specific promoter Gfa2 and the NFAT-inhibitory peptide VIVIT prevented the injury-related loss of basalCA1synaptic strength and key synaptic proteins and reduced the susceptibility to induction of long-term depression. In conjunction with these seemingly beneficial effects, VIVIT treatment elicited a marked increase in the expression of the prosynaptogenic factor SPARCL1 (hevin), especially in hippocampal tissue ipsilateral to the CCI injury. However, in contrast to previous work on Alzheimer’s mouse models, AAVGfa2- VIVIT had no effects on the levels of GFAP and Iba1, suggesting that synaptic benefits of VIVIT were not attributable to a reduction in glial activation per se. Together, the results implicate the astrocytic CN/NFAT4 pathway as a key mechanism for disrupting synaptic remodeling and homeostasis in the hippocampus after acute injury.

Original languageEnglish
Pages (from-to)1502-1515
Number of pages14
JournalJournal of Neuroscience
Volume36
Issue number5
DOIs
StatePublished - Feb 3 2016

Bibliographical note

Publisher Copyright:
© 2016 the authors.

Keywords

  • Astrocytes
  • Brain injury
  • Calcineurin
  • Calcium
  • Glia
  • Synapse

ASJC Scopus subject areas

  • Neuroscience (all)

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