C/EBPß deficiency reshapes microglial gene expression

CCAAT/enhancer binding protein ß (C/EBPß) is a transcription factor that regulates the expression of important pro-inflammatory genes in microglia. Mice deficient for C/EBPß show protection against excitotoxic and ischemic CNS damage but the involvement of the various C/EBPß expressing cell types in this neuroprotective effect is not solved. Since C/EBPß-deficient microglia show attenuated neurotoxicity in culture we hypothesized that specific C/EBPß deficiency in microglia could be neuroprotective in vivo. In this study we have tested this hypothesis by generating mice with myeloid C/EBPß deficiency. Mice with myeloid C/EBPß deficiency were generated by crossing LysMCre and C/EBPßfl/fl mice . Primary microglial cultures from C/EBPßfl/fl (named here as WT) and LysMCre-C/EBPßfl/fl (named here as KO) mice were treated with lipopolysaccharide ± interferon ? (IFN?) for 6 h and gene expression was analyzed by RNA sequencing. LysMCre-C/EBPßfl/fl mice showed an efficiency of C/EBPß deletion of 100% in cultured microglia. Transcriptomic analysis of C/EBPß-deficient primary microglia revealed C/EBPß-dependent expression of 1068 genes, significantly enriched in inflammatory and innate immune responses GO terms. This study provides new data that support a central role for C/EBPß in the biology of activated microglia. Overall design: LysMCre-C/EBPßfl/fl genotype (12 samples): 4 samples treated with LPS, 4 with LPS +IFNg, and 4 vehicle. C/EBPßfl/fl genotype (9 samples): 3 samples treated with LPS, 3 with LPS +IFNg, and 3 vehicle. Design Case (Treatment LPS or LPS +INF) control (No treatment or vehicle) in LysMCre-C/EBPßfl/fl genotype and in C/EBPßfl/fl genotype

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Pulido-Salgado M, Vidal-Taboada JM, Barriga GG, Solà C, Saura J