Project description:In the present study, we hypothesized that C/EBPa (CCAAT/enhancer-binding protein alpha) plays a role in cell regeneration in response to bronchiolar epithelial cell injury. C/EBPa mediated ciliated cell regeneration after naphthalene bronchiolar epithelial cell injury in vivo. Furthermore, we demonstrated that C/EBPa regulates protease/anti-protease balance after lung injury, and intratracheal treatment with anti-protease (BPTI) restored ciliated cell regeneration after naphthalene injury in CebpaD/D mice. Cebpa d/d VS. Control mice 0hr, 3hr and 72hr after naphthalene injury. Three replicates each.
Project description:In the present study, we hypothesized that C/EBPa (CCAAT/enhancer-binding protein alpha) plays a role in cell regeneration in response to bronchiolar epithelial cell injury. C/EBPa mediated ciliated cell regeneration after naphthalene bronchiolar epithelial cell injury in vivo. Furthermore, we demonstrated that C/EBPa regulates protease/anti-protease balance after lung injury, and intratracheal treatment with anti-protease (BPTI) restored ciliated cell regeneration after naphthalene injury in CebpaD/D mice.
Project description:PPARg and C/EBPa cooperate to control preadipocyte differentiation (adipogenesis). However, the factors that regulate PPARg and C/EBPa expression during adipogenesis remain largely unclear. Here we show PTIP, a protein that associates with histone H3K4 methyltransferases, regulates PPARg and C/EBPa expression in mouse embryonic fibroblasts (MEFs) and during preadipocyte differentiation. PTIP deletion in MEFs leads to marked decreases of PPARg expression and PPARg-stimulated C/EBPα expression. Further, PTIP is essential for induction of PPARg and C/EBPa expression during preadipocyte differentiation. Deletion of PTIP impairs the enrichment of H3K4 trimethylation and RNA polymerase II on PPARg and C/EBPa promoters. Accordingly, PTIP-/- MEFs and preadipocytes all show striking defects in adipogenesis. Furthermore, rescue of the adipogenesis defect in PTIP-/- MEFs requires co-expression of PPARg and C/EBPa. Finally, deletion of PTIP in brown adipose tissue significantly reduces tissue weight in mice. Thus, by regulating PPARg and C/EBPa expression, PTIP plays a critical role in adipogenesis.
Project description:Transcription factors are key regulators of hematopoieticstem cells (HSCs) and act through their ability to bind DNA andimpact on gene transcription. Their functions are interpreted inthe complex landscape of chromatin but current knowledge on howthis is achieved is very limited. C/EBPa is an importanttranscriptional regulator of hematopoiesis, but its potentialfunctions in HSCs have remained elusive. Here we report that C/EBPaserves to protect adult HSCs from apoptosis and to maintain theirquiescent state. Consequently, deletion of Cebpa is associatedwith loss of self-renewal and HSC exhaustion. By combining geneexpression analysis with genome-wide assessment of C/EBPa bindingand epigenetic configurations, we show that C/EBPa acts tomodulate the epigenetic states of genes belonging to molecularpathways important for HSC function. Moreover, we demonstrate thatC/EBPa acts as a priming factor at the HSC level to activelypromote myeloid differentiation and counteract lymphoid lineagechoice. Taken together our results show that C/EBPa is a keyregulator of HSC biology, which influences the epigeneticlandscape of HSCs in order to balance different cell fate options.
Project description:Transcription factors are key regulators of hematopoieticstem cells (HSCs) and act through their ability to bind DNA andimpact on gene transcription. Their functions are interpreted inthe complex landscape of chromatin but current knowledge on howthis is achieved is very limited. C/EBPa is an importanttranscriptional regulator of hematopoiesis, but its potentialfunctions in HSCs have remained elusive. Here we report that C/EBPaserves to protect adult HSCs from apoptosis and to maintain theirquiescent state. Consequently, deletion of Cebpa is associatedwith loss of self-renewal and HSC exhaustion. By combining geneexpression analysis with genome-wide assessment of C/EBPa bindingand epigenetic configurations, we show that C/EBPa acts tomodulate the epigenetic states of genes belonging to molecularpathways important for HSC function. Moreover, we demonstrate thatC/EBPa acts as a priming factor at the HSC level to activelypromote myeloid differentiation and counteract lymphoid lineagechoice. Taken together our results show that C/EBPa is a keyregulator of HSC biology, which influences the epigeneticlandscape of HSCs in order to balance different cell fate options. C/EBPaplha binding was assesed in heamatopoietic stem- and progenitor cells (LSK) and in myeloid progenitor cells (GMP) using ChIP-seq
Project description:PPARg and C/EBPa cooperate to control preadipocyte differentiation (adipogenesis). However, the factors that regulate PPARg and C/EBPa expression during adipogenesis remain largely unclear. Here we show PTIP, a protein that associates with histone H3K4 methyltransferases, regulates PPARg and C/EBPa expression in mouse embryonic fibroblasts (MEFs) and during preadipocyte differentiation. PTIP deletion in MEFs leads to marked decreases of PPARg expression and PPARg-stimulated C/EBPα expression. Further, PTIP is essential for induction of PPARg and C/EBPa expression during preadipocyte differentiation. Deletion of PTIP impairs the enrichment of H3K4 trimethylation and RNA polymerase II on PPARg and C/EBPa promoters. Accordingly, PTIP-/- MEFs and preadipocytes all show striking defects in adipogenesis. Furthermore, rescue of the adipogenesis defect in PTIP-/- MEFs requires co-expression of PPARg and C/EBPa. Finally, deletion of PTIP in brown adipose tissue significantly reduces tissue weight in mice. Thus, by regulating PPARg and C/EBPa expression, PTIP plays a critical role in adipogenesis. To identify PTIP-regulated genes, immortalized PTIP conditional knockout PTIPflox/flox MEFs were infected with retroviruses expressing either Cre recombinase or vector alone. We prepared duplicated RNAs from either vector or Cre infected cells (PTIP+/+ or PTIP-/-) for 4 affymetrix microarrays.
Project description:The circadian clock plays a vital role in modulating the cellular immune response. However, its role in mediating pro-inflammatory diabetogenic β-cell injury remains largely unexplored. Our studies demonstrate that conditional deletion of Bmal1 in mouse β-cells was shown to impair the ability of β-cells to recover from streptozotocin-mediated pro-inflammatory injury in vivo, leading to β-cell failure and the development of diabetes. Our study suggests that the β-cell circadian clock mediates β-cell response and recovery from pro-inflammatory injury common to the pathogenesis of diabetes mellitus.
Project description:In nature, plants are constantly exposed to many transient, but recurring, stresses. Thus, to complete their life cycles they require a dynamic balance between capacities to recover following cessation of stress and maintenance of stress memory. Recently, we uncovered a new functional role of autophagy in regulating recovery from heat stress (HS) and resetting cellular memory of HS in Arabidopsis thaliana. Here, we demonstrate that NBR1 (Next-to-BRCA1) plays a crucial role as an adaptor receptor for selective autophagy during recovery from HS. Immunoblot analysis and confocal microscopy revealed that levels of NBR1 protein, NBR1-labeled puncta and NBR1 activities were all higher during the HS recovery phase than before and after this phase. Co-immunoprecipitation analysis of proteins interacting with NBR1 and comparative proteomic analysis of a nbr1 knockout mutant and wild-type plants identified 58 proteins as potential novel targets of NBR1. Cellular, biochemical and functional genetic studies confirmed that NBR1 targets Heat Shock Protein 90 (HSP90) and ROF1, a member of the FKBP family, and mediates their degradation by autophagy, which represses the expression of HSPs regulated by HsfA2 transcription factor and the response to HS. Accordingly, loss-of-function mutation of NBR1 resulted in a stronger HS memory phenotype. Together our results provide new insights into the mechanistic principles by which autophagy regulates plant response to recurrent HS.