High Ca2+ Influx During Traumatic Brain Injury Leads to Caspase-1-Dependent Neuroinflammation and Cell Death

P. M. Abdul-Muneer, Mathew Long, Adriano Andrea Conte, Vijayalakshmi Santhakumar, Bryan J. Pfister

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We investigated the hypothesis that high Ca2+ influx during traumatic brain injury induces the activation of the caspase-1 enzyme, which triggers neuroinflammation and cell apoptosis in a cell culture model of neuronal stretch injury and an in vivo model of fluid percussion injury (FPI). We first established that stretch injury causes a rapid increase in the intracellular Ca2+ level, which activates interleukin-converting enzyme caspase-1. The increase in the intracellular Ca2+ level and subsequent caspase-1 activation culminates into neuroinflammation via the maturation of IL-1β. Further, we analyzed caspase-1-mediated apoptosis by TUNEL staining and PARP western blotting. The voltage-gated sodium channel blocker, tetrodotoxin, mitigated the stretch injury-induced neuroinflammation and subsequent apoptosis by blocking Ca2+ influx during the injury. The effect of tetrodotoxin was similar to the caspase-1 inhibitor, zYVAD-fmk, in neuronal culture. To validate the in vitro results, we demonstrated an increase in caspase-1 activity, neuroinflammation and neurodegeneration in fluid percussion-injured animals. Our data suggest that neuronal injury/traumatic brain injury (TBI) can induce a high influx of Ca2+ to the cells that cause neuroinflammation and cell death by activating caspase-1, IL-1β, and intrinsic apoptotic pathways. We conclude that excess IL-1β production and cell death may contribute to neuronal dysfunction and cognitive impairment associated with TBI.

Original languageEnglish (US)
Pages (from-to)3964-3975
Number of pages12
JournalMolecular Neurobiology
Volume54
Issue number6
DOIs
StatePublished - Aug 1 2017

All Science Journal Classification (ASJC) codes

  • Neurology
  • Cellular and Molecular Neuroscience

Keywords

  • Apoptosis
  • Ca influx
  • Caspase-1
  • Fluid percussion injury
  • IL-1β
  • Neuroinflammation
  • Neuronal stretch injury
  • Traumatic brain injury

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