title: CCAAT/enhancer binding protein β directly regulates the expression of the complement component 3 gene in neural cells: implications for the pro-inflammatory effects of this transcription factor.
abstract: BACKGROUND
  The CCAAT/enhancer-binding protein β (C/EBPβ) is a transcription factor, which was first identified as a regulator of differentiation and inflammatory processes mainly in adipose tissue and liver; however, its function in the brain was largely unknown for many years. Previous studies from our laboratory indicated that C/EBPβ is implicated in inflammatory process and brain injury, since mice lacking this gene were less susceptible to kainic acid-induced injury.
  
  
  METHODS
  We first performed cDNA microarrays analysis using hippocampal RNA isolated from C/EBPβ (+/+) and C/EBPβ (-/-) mice. Immunocytochemical and immunohistochemical studies were done to evaluate C/EBPβ and C3 levels. Transient transfection experiments were made to analyze transcriptional regulation of C3 by C/EBPβ. To knockdown C/EBPβ and C3 expression, mouse astrocytes were infected with lentiviral particles expressing an shRNA specific for C/EBPβ or an siRNA specific for C3.
  
  
  RESULTS
  Among the genes displaying significant changes in expression was complement component 3 (C3), which showed a dramatic decrease in mRNA content in the hippocampus of C/EBPβ (-/-) mice. C3 is the central component of the complement and is implicated in different brain disorders. In this work we have found that C/EBPβ regulates C3 levels in rodents glial in vitro and in the rat Substantia nigra pars compacta (SNpc) in vivo following an inflammatory insult. Analysis of the mouse C3 promoter showed that it is directly regulated by C/EBPβ through a C/EBPβ consensus site located at position -616/-599 of the gene. In addition, we show that depletion of C/EBPβ by a specific shRNA results in a significant decrease in the levels of C3 together with a reduction in the increased levels of pro-inflammatory agents elicited by lipopolysaccharide treatment.
  
  
  CONCLUSIONS
  Altogether, these results indicate that C3 is a downstream target of C/EBPβ, and it could be a mediator of the pro-inflammatory effects of this transcription factor in neural cells.
authors.affiliation: Instituto de Investigaciones Biomédicas, (CSIC-UAM), Arturo Duperier, 4, 28029, Madrid, Spain. ehencinas@iib.uam.es.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. ehencinas@iib.uam.es.
authors.forename: Elena
authors.initials: E
authors.lastname: Hernandez-Encinas
authors.affiliation: Instituto de Investigaciones Biomédicas, (CSIC-UAM), Arturo Duperier, 4, 28029, Madrid, Spain. daguilar@iib.uam.es.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. daguilar@iib.uam.es.
authors.forename: Diana
authors.initials: D
authors.lastname: Aguilar-Morante
authors.affiliation: Instituto de Investigaciones Biomédicas, (CSIC-UAM), Arturo Duperier, 4, 28029, Madrid, Spain. mcortes@mail.rockefeller.edu.|Present address: Laboratory of Neurobiology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA. mcortes@mail.rockefeller.edu.
authors.forename: Marta
authors.initials: M
authors.lastname: Cortes-Canteli
authors.affiliation: Instituto de Investigaciones Biomédicas, (CSIC-UAM), Arturo Duperier, 4, 28029, Madrid, Spain. jmorales@iib.uam.es.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. jmorales@iib.uam.es.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Morales-Garcia
authors.affiliation: Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. elena.gine@med.ucm.es.|Departamento de Bioquímica y Biologia Molecular, Facultad de Medicina, UCM, Plaza Ramón y Cajal s/n, 28040, Madrid, Spain. elena.gine@med.ucm.es.
authors.forename: Elena
authors.initials: E
authors.lastname: Gine
authors.affiliation: Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. piedras3@med.ucm.es.|Departamento de Bioquímica y Biologia Molecular, Facultad de Medicina, UCM, Plaza Ramón y Cajal s/n, 28040, Madrid, Spain. piedras3@med.ucm.es.
authors.forename: Angel
authors.initials: A
authors.lastname: Santos
authors.affiliation: Instituto de Investigaciones Biomédicas, (CSIC-UAM), Arturo Duperier, 4, 28029, Madrid, Spain. aperez@iib.uam.es.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031, Madrid, Spain. aperez@iib.uam.es.
authors.forename: Ana
authors.initials: A
authors.lastname: Perez-Castillo
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D022782:CCAAT-Enhancer-Binding Protein-beta / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D003176:Complement C3 / Q000235:genetics* / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D006624:Hippocampus / Q000166:cytology; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D046228:Microarray Analysis; D009447:Neuroblastoma; D009457:Neuroglia / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011134:Polysaccharides / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D022782:CCAAT-Enhancer-Binding Protein-beta; D003176:Complement C3; D053583:Interleukin-1beta; D010446:Peptide Fragments; D011134:Polysaccharides; C052994:interleukin-1beta (163-171); C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2