title: Atorvastatin prevents age-related and amyloid-β-induced microglial activation by blocking interferon-γ release from natural killer cells in the brain.
abstract: BACKGROUND
  Microglial function is modulated by several factors reflecting the numerous receptors expressed on the cell surface, however endogenous factors which contribute to the age-related increase in microglial activation remain largely unknown. One possible factor which may contribute is interferon-γ (IFNγ). IFNγ has been shown to increase in the aged brain and potently activates microglia, although its endogenous cell source in the brain remains unidentified.
  
  
  METHODS
  Male Wistar rats were used to assess the effect of age and amyloid-β (Aβ) on NK cell infiltration into the brain. The effect of the anti-inflammatory compound, atorvastatin was also assessed under these conditions. We measured cytokine and chemokine (IFNγ, IL-2, monocyte chemoattractant protein-1 (MCP-1) and IFNγ-induced protein 10 kDa (IP-10)), expression in the brain by appropriate methods. We also looked at NK cell markers, CD161, NKp30 and NKp46 using flow cytometry and western blot.
  
  
  RESULTS
  Natural killer (NK) cells are a major source of IFNγ in the periphery and here we report the presence of CD161+ NKp30+ cells and expression of CD161 and NKp46 in the brain of aged and Aβ-treated rats. Furthermore, we demonstrate that isolated CD161+ cells respond to interleukin-2 (IL-2) by releasing IFNγ. Atorvastatin, the HMG-CoA reductase inhibitor, attenuates the increase in CD161 and NKp46 observed in hippocampus of aged and Aβ-treated rats. This was paralleled by a decrease in IFNγ, markers of microglial activation and the chemokines, MCP-1 and IP-10 which are chemotactic for NK cells.
  
  
  CONCLUSIONS
  We propose that NK cells contribute to the age-related and Aβ-induced neuroinflammatory changes and demonstrate that these changes can be modulated by atorvastatin treatment.
authors: Physiology Department, Trinity College Institute for Neuroscience, Trinity College, Dublin 2, Ireland. lyonsan@tcd.ie
authors: Anthony
authors: A
authors: Lyons
authors: Kevin J
authors: KJ
authors: Murphy
authors: Rachael
authors: R
authors: Clarke
authors: Marina A
authors: MA
authors: Lynch
mesh_terms: D000375:Aging / Q000502:physiology*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology; D000069059:Atorvastatin; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000166:cytology / Q000378:metabolism; D006538:Heptanoic Acids / Q000494:pharmacology*; D007371:Interferon-gamma / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D017628:Microglia / Q000166:cytology / Q000378:metabolism*; D055651:NK Cell Lectin-Like Receptor Subfamily B / Q000378:metabolism; D055627:Natural Cytotoxicity Triggering Receptor 1 / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016229:Amyloid beta-Peptides; D000924:Anticholesteremic Agents; D015415:Biomarkers; D006538:Heptanoic Acids; D055651:NK Cell Lectin-Like Receptor Subfamily B; D055627:Natural Cytotoxicity Triggering Receptor 1; D011758:Pyrroles; D007371:Interferon-gamma; D000069059:Atorvastatin