Microglia-Derived Cytokines/Chemokines Are Involved in the Enhancement of LPS-Induced Loss of Nigrostriatal Dopaminergic Neurons in DJ-1 Knockout Mice

PLoS One. 2016 Mar 16;11(3):e0151569. doi: 10.1371/journal.pone.0151569. eCollection 2016.

Abstract

Mutation of DJ-1 (PARK7) has been linked to the development of early-onset Parkinson's disease (PD). However, the underlying molecular mechanism is still unclear. This study is aimed to compare the sensitivity of nigrostriatal dopaminergic neurons to lipopolysaccharide (LPS) challenge between DJ-1 knockout (KO) and wild-type (WT) mice, and explore the underlying cellular and molecular mechanisms. Our results found that the basal levels of interferon (IFN)-γ (the hub cytokine) and interferon-inducible T-cell alpha chemoattractant (I-TAC) (a downstream mediator) were elevated in the substantia nigra of DJ-1 KO mice and in microglia cells with DJ-1 deficiency, and the release of cytokine/chemokine was greatly enhanced following LPS administration in the DJ-1 deficient conditions. In addition, direct intranigral LPS challenge caused a greater loss of nigrostriatal dopaminergic neurons and striatal dopamine content in DJ-1 KO mice than in WT mice. Furthermore, the sensitization of microglia cells to LPS challenge to release IFN-γ and I-TAC was via the enhancement of NF-κB signaling, which was antagonized by NF-κB inhibitors. LPS-induced increase in neuronal death in the neuron-glia co-culture was enhanced by DJ-1 deficiency in microglia, which was antagonized by the neutralizing antibodies against IFN-γ or I-TAC. These results indicate that DJ-1 deficiency sensitizes microglia cells to release IFN-γ and I-TAC and causes inflammatory damage to dopaminergic neurons. The interaction between the genetic defect (i.e. DJ-1) and inflammatory factors (e.g. LPS) may contribute to the development of PD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Chemokines / physiology*
  • Corpus Striatum / cytology
  • Corpus Striatum / drug effects*
  • Corpus Striatum / metabolism
  • Cytokines / physiology*
  • Dopamine / metabolism*
  • Lipopolysaccharides / pharmacology*
  • Mice
  • Mice, Knockout
  • Microglia / metabolism*
  • Neurons / metabolism*
  • Oncogene Proteins / genetics
  • Oncogene Proteins / physiology*
  • Peroxiredoxins / genetics
  • Peroxiredoxins / physiology*
  • Protein Deglycase DJ-1
  • Substantia Nigra / cytology
  • Substantia Nigra / drug effects*
  • Substantia Nigra / metabolism

Substances

  • Chemokines
  • Cytokines
  • Lipopolysaccharides
  • Oncogene Proteins
  • Peroxiredoxins
  • PARK7 protein, mouse
  • Protein Deglycase DJ-1
  • Dopamine

Grants and funding

The study was financially supported by the grant MOST 102-2321-B-002-016 from the Ministry of Science and Technology, Taiwan, R.O.C. to H.H.L. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.