Project description:We previously identified C/EBPβ as an inhibitor of myogenic differentiation and a regulator of muscle satellite cell self-renewal. We found that C/EBPβ is regulated during the transition from proliferation to growth arrest in myoblasts and overexpression of C/EBPβ in myoblasts promotes cell growth arrest in vitro and improves engraftment of satellite cells into the stem cell niche in vivo. To identify the molecular mechanism by which C/EBPβ regulates myoblast proliferation and growth arrest, we performed RNA-seq on C/EBPβ-overexpressing myoblasts.
Project description:CCAAT/enhancer binding protein β (C/EBPβ) is a transcription factor that regulates the expression of important pro-inflammatory genes in microglia. Mice deficient for C/EBPβ show protection against excitotoxic and ischemic CNS damage but the involvement of the various C/EBPβ expressing cell types in this neuroprotective effect is not solved. Since C/EBPβ-deficient microglia show attenuated neurotoxicity in culture we hypothesized that specific C/EBPβ deficiency in microglia could be neuroprotective in vivo. In this study we have tested this hypothesis by generating mice with myeloid C/EBPβ deficiency. Mice with myeloid C/EBPβ deficiency were generated by crossing LysMCre and C/EBPβfl/fl mice . Primary microglial cultures from C/EBPβfl/fl (named here as WT) and LysMCre-C/EBPβfl/fl (named here as KO) mice were treated with lipopolysaccharide ± interferon γ (IFNγ) for 6 h and gene expression was analyzed by RNA sequencing. LysMCre-C/EBPβfl/fl mice showed an efficiency of C/EBPβ deletion of 100% in cultured microglia. Transcriptomic analysis of C/EBPβ-deficient primary microglia revealed C/EBPβ-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/EBPβ in the biology of activated microglia.
Project description:Our previous studies have shown that C/EBPβ plays a critical role in human endometrial stromal decidualization. In order to identify the molecular pathways regulated by C/EBPβ during decidualization, we performed gene expression profiling using RNA isolated from normal and C/EBPβ-deficient human endometrial stromal cells. The microarray results revealed that several key regulators of stromal differentiation, such as BMP2, Wnt4, IL-11Rα and STAT3, operate downstream of C/EBPβ during decidualization. Further studies revealed that STAT3 is a direct target of C/EBPβ and plays an important role in cytokine signal during the decidualization process. Gene expression profiling, using STAT3-deficient HESCs, showed an extensive overlap of pathways downstream of STAT3 and C/EBPβ during stromal cell differentiation.
Project description:C/EBPβ (CCAAT enhancer binding protein) is a transcription factor that plays a crucial role in survival and transformation of ALK+ anaplastic large cell lymphoma (ALCL). The aim of this study was to identify the downstream targets of C/EBPβ responsible for ALK-mediated oncogenesis. C/EBPβ was knocked down in ALK+ ALCL cell lines with a C/EBPβ-shRNA, followed by gene expression profiling (GEP). GEP analysis revealed a reproducible signature of genes that were significantly regulated by C/EBPβ. Classification into biological categories revealed overrepresentation of genes involved in the immune response, apoptosis and cell proliferation. Transcriptional regulation by C/EBPβ was found in 6 of 11 (BCL2A1, G0S2, TRIB1, S100A9, DDX21 and DDIT4) genes investigated by chromatin immunoprecipitation. We demonstrated that BCL2A1, G0S2 and DDX21 play a crucial role in survival and proliferation of ALK+ ALCL cells. DDX21, a gene involved in rRNA biogenesis, was found differentially overexpressed in primary ALK+ ALCL cases. All three candidate genes were validated in primary ALCL cases by either immunohistochemistry or RT-qPCR. In conclusion, we identified and validated several key C/EBPβ-regulated genes with major impact on survival and cell growth in ALK+ ALCL, supporting the central role of C/EBPβ in ALK-mediated oncogenesis. Kijk and SUDHL1 cell lines transfected with shRNA for C/EBPbeta were compared to control cells (3 biological replicates per group) and untreated cells (1 biological replicate)