High-mobility group box 1-mediated hippocampal microglial activation induces cognitive impairment in mice with neuropathic pain

Kazue Hisaoka-Nakashima, Kazuto Ohata, Natsuki Yoshimoto, Shintarou Tokuda, Nanako Yoshii, Yoki Nakamura, Dengli Wang, Keyue Liu, Hidenori Wake, Takayuki Yoshida, Yukio Ago, Kouichi Hashimoto, Masahiro Nishibori, Norimitsu Morioka

Research output: Contribution to journalArticlepeer-review

Abstract

Clinical evidence indicates that cognitive impairment is a common comorbidity of chronic pain, including neuropathic pain, but the mechanism underlying cognitive impairment remains unclear. Neuroinflammation plays a critical role in the development of both neuropathic pain and cognitive impairment. High-mobility group box 1 (HMGB1) is a proinflammatory molecule and could be involved in neuroinflammation-mediated cognitive impairment in the neuropathic pain state. Hippocampal microglial activation in mice has been associated with cognitive impairment. Thus, the current study examined a potential role of HMGB1 and microglial activation in cognitive impairment in mice with neuropathic pain due to a partial sciatic nerve ligation (PSNL). Mice developed cognitive impairment over two weeks, but not one week, after nerve injury. Nerve-injured mice demonstrated decreased nuclear fraction HMGB1, suggesting increased extracellular release of HMGB1. Furthermore, two weeks after PSNL, significant microglia activation was observed in hippocampus. Inhibition of microglial activation with minocycline, local hippocampal microglia depletion with clodronate liposome, or blockade of HMGB1 with either glycyrrhizic acid (GZA) or anti-HMGB1 antibody in PSNL mice reduced hippocampal microglia activation and ameliorated cognitive impairment. Other changes in the hippocampus of PSNL mice potentially related to cognitive impairment, including decreased hippocampal neuron dendrite length and spine densities and decreased α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor (AMPAR) subunits, were prevented with anti-HMGB1 antibody treatment. The current findings suggest that neuro-inflammation involves a number of cellular-level changes and microglial activation. Blocking neuro-inflammation, particularly through blocking HMGB1 could be a novel approach to reducing co-morbidities such as cognitive impairment associated with neuropathic pain.

Original languageEnglish
Article number114146
JournalExperimental Neurology
Volume355
DOIs
Publication statusPublished - Sep 2022
Externally publishedYes

Keywords

  • Cognitive impairment
  • HMGB1
  • Microglia
  • Neural plasticity
  • Neuro-inflammation
  • Neuropathic pain
  • Novel object recognition

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience

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