Microglial activation induced by neurodegeneration: a proteomic analysis.
Neuroinflammation mediated by microglial activation appears to play an essential role in the pathogenesis of Parkinson disease; however, the mechanisms by which microglia are activated are not fully understood. Thus, we first evaluated the effects of two parkinsonian toxicants, manganese ethylene bisdithiocarbamate (Mn-EBDC) and 1-methyl-4-phenylpyridine (MPP+), on microglial activation as well as associated dopaminergic (DAergic) neurotoxicity in primary cell culture systems. The results demonstrated that, when rat primary mesencephalic neuron-enriched or neuron-microglia mixed cultures were treated with Mn-EBDC at 2-8 microm or MPP+ at 0.25-5 microm, respectively, for 7 days, both toxicants were capable of inducing DAergic neurodegeneration as well as activating microglia via a mechanism secondary to DAergic neurodegeneration. Furthermore activated microglia subsequently enhanced DAergic neurotoxicity induced by Mn-EBDC or MPP+. Detailed scrutiny of neuron-microglia interactions identified a fraction of the conditioned media derived from a DAergic cell line treated with Mn-EBDC or MPP+ that potently activated microglia. To further define potential mediators leading to microglial activation secondary to neurodegeneration, we utilized a quantitative proteomic technique termed SILAC (for stable isotope labeling by amino acids in cell culture) to compare the protein profiles of MPP+-treated cellular fraction that mediated microglial activation as compared with controls. The search revealed numerous novel proteins that are potentially important in neurodegeneration-mediated microglial activation, a process believed to be critical in Parkinson disease progression.
Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104, USA.
Yong
Y
Zhou
Yan
Y
Wang
Monika
M
Kovacs
Jinghua
J
Jin
Jing
J
Zhang
D015655:1-Methyl-4-phenylpyridinium / Q000494:pharmacology / Q000633:toxicity; D000818:Animals; D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D005028:Ethylenebis(dithiocarbamates) / Q000494:pharmacology / Q000633:toxicity; D008565:Membrane Proteins / Q000145:classification / Q000378:metabolism; D017628:Microglia / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D009410:Nerve Degeneration / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D020258:Neurotoxicity Syndromes / Q000378:metabolism; D009942:Organometallic Compounds / Q000494:pharmacology / Q000633:toxicity; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics; D051381:Rats; D017207:Rats, Sprague-Dawley
D017077:Culture Media, Conditioned; D005028:Ethylenebis(dithiocarbamates); D008565:Membrane Proteins; D009942:Organometallic Compounds; D020543:Proteome; C471036:manganese ethylenebis(dithiocarbamate); D015655:1-Methyl-4-phenylpyridinium