title: Microglial p53 activation is detrimental to neuronal synapses during activation-induced inflammation: Implications for neurodegeneration.
abstract: P53 is a tumour suppressor protein thought to be primarily involved in cancer biology, but recent evidence suggests it may also coordinate novel functions in the CNS, including mediation of pathways underlying neurodegenerative disease. In microglia, the resident immune cells of the brain, p53 activity can promote an activation-induced pro-inflammatory phenotype Jayadev et al. (2011) [1], as well as neurodegeneration Davenport et al. (2010) [2]. Synapse degeneration is one of the earliest pathological events in many chronic neurodegenerative diseases Conforti et al. (2007) and Clare et al. (2010) [3,4] and may be influenced by early microglial responses. Here we examined synaptic properties of neurons following modulation of p53 activity in rat microglia exposed to inflammatory stimuli. A significant reduction in the expression of the neuronal synaptic markers synaptophysin and drebrin, occurred following microglial activation and was seen prior to any visible signs of neuronal cell death, including neuronal cleaved caspase-3 activation. This synaptic marker loss together with microglial secretion of the inflammatory cytokines tumour necrosis factor α (TNF-α) and interleukin 1-β (IL-1β) was abolished by the removal of microglia or inhibition of microglial p53 activation. These results suggest that transcriptional-dependent p53 activities in microglia may drive a non-cell autonomous process of synaptic degeneration in neurons during neuroinflammatory degenerative diseases.
authors.affiliation: Department of Neurology, University of Washington, 1959 NE Pacific Street, Seattle, WA 98103, United States. Electronic address: jjebelli@uw.edu.
authors.forename: Joseph
authors.initials: J
authors.lastname: Jebelli
authors.affiliation: Institute of Psychiatry, Kings College London, 16 De Crespigny Park, London SE5 8AF, UK.
authors.forename: Claudie
authors.initials: C
authors.lastname: Hooper
authors.affiliation: Department of Neuroinflammation, University College London Institute of Neurology, 1 Wakefield Street, London WC1N 1PJ, UK. Electronic address: j.pocock@ucl.ac.uk.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Pocock
mesh_terms: D000818:Animals; D017209:Apoptosis; D052160:Benzothiazoles / Q000494:pharmacology; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D008070:Lipopolysaccharides / Q000494:pharmacology; D017628:Microglia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D013449:Sulfonamides / Q000494:pharmacology; D013569:Synapses / Q000378:metabolism; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: C545747:2-phenylacetylenesulfonamide; D052160:Benzothiazoles; D008070:Lipopolysaccharides; D013449:Sulfonamides; D016159:Tumor Suppressor Protein p53; D014050:Toluene; C121565:pifithrin
keywords: Microglia; Neurodegeneration; P53; Synapse