High mobility group box protein-1 promotes cerebral edema after traumatic brain injury via activation of toll-like receptor 4

Melissa D. Laird, Jessica S. Shields, Sangeetha Sukumari Ramesh, Donald E. Kimbler, R. David Fessler, Basheer Shakir, Patrick Youssef, Nathan Eugene Yanasak, John R Vender, Krishnan Michael Dhandapani

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Cerebral edema, a life-threatening medical complication, contributes to elevated intracranial pressure (ICP) and a poor clinical prognosis after TBI. Unfortunately, treatment options to reduce post-traumatic edema remain suboptimal, due in part, to a dearth of viable therapeutic targets. Herein, we tested the hypothesis that cerebral innate immune responses contribute to edema development after TBI. Our results demonstrate that high-mobility group box protein 1 (HMGB1) was released from necrotic neurons via a NR2B-mediated mechanism. HMGB1 was clinically associated with elevated ICP in patients and functionally promoted cerebral edema after TBI in mice. The detrimental effects of HMGB1 were mediated, at least in part, via activation of microglial toll-like receptor 4 (TLR4) and the subsequent expression of the astrocytic water channel, aquaporin-4 (AQP4). Genetic or pharmacological (VGX-1027) TLR4 inhibition attenuated the neuroinflammatory response and limited post-traumatic edema with a delayed, clinically implementable therapeutic window. Human and rodent tissue culture studies further defined the cellular mechanisms demonstrating neuronal HMGB1 initiates the microglial release of interleukin-6 (IL-6) in a TLR4 dependent mechanism. In turn, microglial IL-6 increased the astrocytic expression of AQP4. Taken together, these data implicate microglia as key mediators of post-traumatic brain edema and suggest HMGB1-TLR4 signaling promotes neurovascular dysfunction after TBI.

Original languageEnglish (US)
Pages (from-to)26-38
Number of pages13
JournalGlia
Volume62
Issue number1
DOIs
StatePublished - Jan 1 2014

Fingerprint

HMGB1 Protein
Toll-Like Receptor 4
Brain Edema
Aquaporin 4
Edema
Intracranial Hypertension
Interleukin-6
Aquaporins
Microglia
Innate Immunity
Rodentia
Therapeutics
Traumatic Brain Injury
Pharmacology
Morbidity
Neurons
Mortality

Keywords

  • Controlled cortical impact
  • DAMP
  • Innate immunity
  • Intracranial pressure
  • Neuroinflammation

ASJC Scopus subject areas

  • Neurology
  • Cellular and Molecular Neuroscience

Cite this

High mobility group box protein-1 promotes cerebral edema after traumatic brain injury via activation of toll-like receptor 4. / Laird, Melissa D.; Shields, Jessica S.; Sukumari Ramesh, Sangeetha; Kimbler, Donald E.; Fessler, R. David; Shakir, Basheer; Youssef, Patrick; Yanasak, Nathan Eugene; Vender, John R; Dhandapani, Krishnan Michael.

In: Glia, Vol. 62, No. 1, 01.01.2014, p. 26-38.

Research output: Contribution to journalArticle

Laird, Melissa D. ; Shields, Jessica S. ; Sukumari Ramesh, Sangeetha ; Kimbler, Donald E. ; Fessler, R. David ; Shakir, Basheer ; Youssef, Patrick ; Yanasak, Nathan Eugene ; Vender, John R ; Dhandapani, Krishnan Michael. / High mobility group box protein-1 promotes cerebral edema after traumatic brain injury via activation of toll-like receptor 4. In: Glia. 2014 ; Vol. 62, No. 1. pp. 26-38.
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