Deletion of the NF-κB subunit p65/RelA in the hematopoietic compartment leads to defects in hematopoietic stem cell function.
Ontology highlight
ABSTRACT: Deletion of the NF-κB subunit p65/RelA in the hematopoietic compartment results in gene expression changes in lineage-Flk2-c-kit+Sca-1+ cells from mouse bone marrow.
Project description:Deletion of the NF-κB subunit p65/RelA in the hematopoietic compartment results in gene expression changes in lineage-Flk2-c-kit+Sca-1+ cells from mouse bone marrow. We analyzed lineage-Flk2-c-kit+Sca-1+ cells from the bone marrow of p65 wild-type or knockout mice using the Affymetrix Mouse Exon 1.0 ST platform. Array data was processed by Affymetrix Exon Array Computational Tool. No technical replicates were performed.
Project description:Hematopoiesis is a tightly regulated process resulting in the production of blood cells. Self-renewal and differentiation of hematopoietic stem cells (HSCs) are key processes in hematopoietic development. Disruption of these steps can lead to altered cell distribution and disease. To investigate the role of the nuclear factor-?B subunit RelA/p65 in the regulation of HSCs in vivo, we generated mice lacking RelA/p65 in the hematopoietic compartment. Using this model system, we show that loss of p65 severely impairs HSC function and occurs in conjunction with increased hematopoietic stem and progenitor cell cycling, extramedullary hematopoiesis, and differentiation defects. Gene array studies of phenotypic HSCs indicate the up-regulation of genes normally expressed in lineage restricted cells, as well as the down-regulation of genes involved in HSC maintenance and homeostasis. We hypothesize that changes in gene expression in p65-deficient cells lead to decreased self-renewal and differentiation efficiency of hematopoietic stem and progenitor cells. These studies demonstrate that p65 is an important regulator of hematopoiesis through the transcription of genes involved in HSC fate.
Project description:Smoking is the most important risk factor for both lung cancer (LC) and chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the role of myeloid cell NF-kB in the regulation of tumor cell growth signaling. We subjected mice lacking myeloid RelA/p65 to a metastatic LC model. Cigarette smoke (CS) exposure significantly increased the proliferation of Lewis lung carcinoma cell (LLC) tumors in wild type mice. In CS exposed mice lacking myeloid RelA/p65, the tumor growth was largely inhibited. Transcriptome and pathway analysis of cancer tissue revealed a fundamental impact of myeloid cells on various growth signaling pathways. Myeloid RelA/p65 is necessary to link smoke-induced inflammation with LC growth. Keywords: Expression profiling by array Analysis of gene expression in lewis lung carcinoma cells resected from lungs of WT and RelA/p65 deficient mice exposed to smoke or air. Four different samples were analyzed (3 replicates each).
Project description:Smoking is the most important risk factor for both lung cancer (LC) and chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the role of myeloid cell NF-kB in the regulation of tumor cell growth signaling. We subjected mice lacking myeloid RelA/p65 to a metastatic LC model. Cigarette smoke (CS) exposure significantly increased the proliferation of Lewis lung carcinoma cell (LLC) tumors in wild type mice. In CS exposed mice lacking myeloid RelA/p65, the tumor growth was largely inhibited. Transcriptome and pathway analysis of cancer tissue revealed a fundamental impact of myeloid cells on various growth signaling pathways. Myeloid RelA/p65 is necessary to link smoke-induced inflammation with LC growth. Keywords: Expression profiling by array
Project description:Post-translational modification of NF-κB subunits provides a mechanism to differentially regulate their activity in response to the many stimuli that can induce this pathway. However, the physiological significance of these modifications is largely unknown and it remains unclear if these have a critical role in the normal and pathological functions of NF-κB in vivo. Among these, phosphorylation of the RelA(p65) Thr505 residue has been described as an important regulator of NF-κB activity in cell lines but its physiological significance was not known. Therefore, to learn more about the role of this pathway in vivo, we generated a knockin mouse with a RelA T505A mutation. Unlike RelA knockout mice, the RelA T505A mice develop normally but exhibit aberrant hepatocyte proliferation following liver partial hepatectomy or damage resulting from carbon tetrachloride treatment. Consistent with these effects, RelA T505A mice exhibit earlier onset of cancer in the N-nitrosodiethylamine (DEN) model of hepatocellular carcinoma. This data reveals a critical pathway controlling NF-κB function in the liver that acts to suppress tumour-promoting activities of RelA.
Project description:Using a mouse model with hepatocyte-specific deletion of transcription factor NF-κB RelA (p65), our group has previously revealed the important role of RelA in inducing the acute phase response, maintaining host defense, and preventing liver injury during sepsis. To goal of this study was determine the influence of RelA on hepatic gene changes that provide liver protection during infection. Mice were generated with functional deletion of NF-kappaB RelA (p56) in hepatocytes using a Cre-LoxP system. Mutant mice expressed Cre-recombinase under the transcriptional control of an albumin promotor and homozygous floxed RelA alleles. Wild type control mice lack the Cre-recombinase. Microarray analysis was performed on liver RNA collected from both genotypes of mice in the absence and presence of pneumococcal bacteremia.
Project description:A common response to physiological duress is the hepatic acute phase response, a process during which the expression of many genes is altered in the liver. Amongst these transcripts are those encoding acute phase proteins, defined as circulating proteins with significantly changed concentrations during an acute phase response. The goal of this study was to determine the influence of NF-kappaB RelA (p65) on hepatic gene changes including but not limited to acute phase proteins during bacterial pneumonia. Using the Cre-LoxP system, mice were generated with functional deletion of NF-kappaB RelA (p65) in hepatocytes. In mutant mice, Cre-recombinase was expressed under transcriptional control of an albumin promoter in the presence of homozygous floxed alleles for RelA. Wild-type control mice lacked the Cre-recombinase transgene. Microarray analysis was performed on liver RNA collected from both genotypes of mice in the absence and presence of pneumococcal pneumonia. RNA from 2 separate groups of mice (3 mice per group) was analyzed: 1) Control mice infected intratracheally for 24h with 10^6 CFU of Streptococcus pneumoniae (serotype 3); and 2) Mutant mice infected intratracheally for 24h with 10^6 CFU of Streptococcus pneumoniae (serotype 3).