title: CCL2/MCP-1 modulation of microglial activation and proliferation.
abstract: BACKGROUND
  Monocyte chemoattractant protein (CCL2/MCP-1) is a chemokine that attracts cells involved in the immune/inflammatory response. As microglia are one of the main cell types sustaining inflammation in brain, we proposed here to analyze the direct effects of MCP-1 on cultured primary microglia.
  
  
  METHODS
  Primary microglia and neuronal cultures were obtained from neonatal and embryonic Wistar rats, respectively. Microglia were incubated with different concentrations of recombinant MCP-1 and LPS. Cell proliferation was quantified by measuring incorporation of bromodeoxyuridine (BrdU). Nitrite accumulation was measured using the Griess assay. The expression and synthesis of different proteins was measured by RT-PCR and ELISA. Cell death was quantified by measuring release of LDH into the culture medium.
  
  
  RESULTS
  MCP-1 treatment (50 ng/ml, 24 h) did not induce morphological changes in microglial cultures. Protein and mRNA levels of different cytokines were measured, showing that MCP-1 was not able to induce proinflammatory cytokines (IL-1β, IL6, MIP-1α), either by itself or in combination with LPS. A similar lack of effect was observed when measuring inducible nitric oxide synthase (NOS2) expression or accumulation of nitrites in the culture media as a different indicator of microglial activation. MCP-1 was also unable to alter the expression of different trophic factors that were reduced by LPS treatment. In order to explore the possible release of other products by microglia and their potential neurotoxicity, neurons were co-cultured with microglia: no death of neurons could be detected when treated with MCP-1. However, the presence of MCP-1 induced proliferation of microglia, an effect opposite to that observed with LPS.
  
  
  CONCLUSIONS
  These data indicate that, while causing migration and proliferation of microglia, MCP-1 does not appear to directly activate an inflammatory response in this cell type, and therefore, other factors may be necessary to cause the changes that result in the neuronal damage commonly observed in situations where MCP-1 levels are elevated.
authors: Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Avenida Complutense s/n, Madrid, Spain.
authors: Ara E
authors: AE
authors: Hinojosa
authors: Borja
authors: B
authors: Garcia-Bueno
authors: Juan C
authors: JC
authors: Leza
authors: Jose L M
authors: JL
authors: Madrigal
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000494:pharmacology*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar
chemical_list: C491766:Ccl2 protein, rat; D018797:Cell Cycle Proteins; D018932:Chemokine CCL2; D016207:Cytokines; D036341:Intercellular Signaling Peptides and Proteins