We investigated the route of neurotrophic cue delivery to the nerves
Loss of p53 drives neuron reprogramming in head and neck cancer.
Specimen part
View SamplesThe response of cells to hypoxia is characterised by co-ordinated regulation of many genes. Studies of the regulation of the expression of many of these genes by oxygen has implicated a role for the heterodimeric transcription factor hypoxia inducible factor (HIF). The mechanism of oxygen sensing which controls this heterodimeric factor is via oxygen dependent prolyl and asparaginyl hydroxylation by specific 2-oxoglutarate dependent dioxygenases (PHD1, PHD2, PHD3 and FIH-1). Whilst HIF appears to have a major role in hypoxic regulation of gene expression, it is unclear to what extent other transcriptional mechanisms are also involved in the response to hypoxia. The extent to which 2-oxoglutarate dependent dioxygenases are responsible for the oxygen sensing mechanism in HIF-independent hypoxic gene regulation is also unclear. Both the prolyl and asparaginyl hydroxylases can be inhibited by dimethyloxalylglycine (DMOG). Such inhibition can produce activation of the HIF system with enhanced transcription of target genes and might have a role in the therapy of ischaemic disease. We have examined the extent to which the HIF system contributes to the regulation of gene expression by hypoxia, to what extent 2-oxoglutarate dependent dioxygenase inhibitor can mimic the hypoxic response and the nature of the global transcriptional response to hypoxia. We have utilised microarray assays of mRNA abundance to examine the gene expression changes in response to hypoxia and to DMOG. We demonstrate a large number of hypoxically regulated genes, both known and novel, and find a surprisingly high level of mimicry of the hypoxic response by use of the 2-oxoglutarate dependent dioxygenase inhibitor, dimethyloxalylglycine. We have also used microarray analysis of cells treated with small interfering RNA (siRNA) targeting HIF-1alpha and HIF-2alpha to demonstrate the differing contributions of each transcription factor to the transcriptional response to hypoxia. Candidate transcripts were confirmed using an independent microarray platform and real-time PCR. The results emphasise the critical role of the HIF system in the hypoxic response, whilst indicating the dominance of HIF-1alpha and defining genes that only respond to HIF-2alpha.
Concordant regulation of gene expression by hypoxia and 2-oxoglutarate-dependent dioxygenase inhibition: the role of HIF-1alpha, HIF-2alpha, and other pathways.
No sample metadata fields
View SamplesMutations involving the NFKB pathway are present in at least 17% of multiple myeloma (MM) tumors and 40% of MM cell lines (MMCL). These mutations, which are thought to be progression events, enable MM tumors to become less dependent on extrinsic bone marrow signals that activate NFKB. Studies on a panel of 50 MMCL provide some clarification of the mechanisms through which these mutations act and the significance of classical vs alternative activation of NFKB. First, only one mutation (NFKB2) selectively activates the alternative pathway, whereas several mutations (CYLD, NFKB1, TACI) selectively activate the classical pathway. However, most mutations affecting NIK level (NIK, TRAF2, TRAF3, cIAP1&2, CD40) activate the alternative but often both pathways. Second, we confirm the critical role of TRAF2 in regulating NIK degradation, whereas TRAF3 enhances but is not essential for cIAP1/2-mediated proteosomal degradation of NIK in MM.
Classical and/or alternative NF-kappaB pathway activation in multiple myeloma.
Cell line
View SamplesThe aim of the study is to evaluate oxygen regulated gene expression in human peripheral blood lymphocytes using microarray analysis.
Variations within oxygen-regulated gene expression in humans.
No sample metadata fields
View SamplesPRC, a member of the PGC-1 coactivator family, is responsive to serum growth factors and up regulated in proliferating cells. Here, we investigated its in vivo role by stably silencing PRC expression with two different short hairpin RNAs (shRNA#1 and shRNA#4) that were lentivirally introduced into U2OS cells. ShRNA#1 transductants exhibited nearly complete knockdown of PRC protein whereas shRNA#4 transductants expressed PRC protein at approximately 15 percent of the control level. Complete PRC silencing by shRNA#1 resulted in a severe inhibition of respiratory growth, reduced expression of respiratory protein subunits from complexes I, II, III and IV, markedly lower complex I and IV respiratory enzyme levels and diminished mitochondrial ATP production. Surprisingly, shRNA#1 transductants exhibited a striking proliferation of abnormal mitochondria that were devoid of organized cristae and displayed severe membrane abnormalities. Although shRNA#4 transductants had normal respiratory subunit expression and a moderately diminished respiratory growth rate, both transductants showed markedly reduced growth on glucose accompanied by inhibition of G1/S cell cycle progression. Microarray analysis revealed striking overlaps in the genes affected by PRC silencing in the two transductants and the functional identities of these overlapping genes were consistent with the observed mitochondrial and cell growth phenotypes. The consistency between phenotype and PRC expression levels in the two independent transductant lines argues that the defects result from PRC silencing and not from off target effects. These results support a role for PRC in the integration of pathways directing mitochondrial respiratory function and cell growth.
Short hairpin RNA-mediated silencing of PRC (PGC-1-related coactivator) results in a severe respiratory chain deficiency associated with the proliferation of aberrant mitochondria.
No sample metadata fields
View SamplesDicamba is an auxin-like herbicide that can stimulate the production of ethylene and ABA biosynthesis. The subsequent stomatal closure and build-up of reactive oxygen species is hypothesized to contribute to plant death.
Mutant analysis in Arabidopsis provides insight into the molecular mode of action of the auxinic herbicide dicamba.
Specimen part
View SamplesHuman blood monocytes were differentiated over six days with either 100 ng/ml M-CSF or 1 umol/l CXCL4
CXC chemokine ligand 4 induces a unique transcriptome in monocyte-derived macrophages.
Specimen part
View SamplesNatural killer (NKT) T cells exhibit tissue distribution, surface phenotype, and functional responses that are strikingly different from those of conventional T cells. The transcription factor PLZF is responsible for most of these properties, as its ectopic expression in conventional T cells is sufficient to confer to them an NKT-like phenotype. The molecular program downstream of PLZF, however, is largely unexplored.
PLZF Controls the Expression of a Limited Number of Genes Essential for NKT Cell Function.
Sex, Specimen part
View SamplesThe study was designed in order to identify genes differentially expressed when glucocorticoid signaling is blocked by a glucocorticoid-receptor antagonist (RU486 mifepristone) in the context of brain inflammation induced by bacterial lipopolysaccharide (LPS). LPS is only able to cause murine brain damage in our experimental conditions upon RU486 pre-treatment. Hence, the study may reveal potential candidate genes to mediate neuroprotection or neurotoxicity. Due to the factorial design of the experiment, RU486 main-effect could be dissociated from the effects resultant of RU486/inflammation interaction. In addition, brain dissection was conducted to verify the effects in the brain side ipsilateral or contralateral to the site of intracerebral LPS infusion.
Genes involved in the balance between neuronal survival and death during inflammation.
Sex, Age, Specimen part
View SamplesCritically ill preterm infants experience multiple stressors while hospitalized. Morphine is commonly prescribed to ameliorate their pain and stress. We hypothesized that neonatal stress will have a dose-dependent effect on hippocampal gene expression, and these effects will be altered by morphine treatment. Male C57BL/6 mice were exposed to 5 treatment conditions between postnatal day 5 and 9: 1) Control, 2) mild stress + saline, 3) mild stress + morphine, 4) severe stress + saline and 5) severe stress + morphine. Hippocampal RNA was extracted and analyzed using Affymetrix Mouse Gene 1.0 ST Arrays. Single gene analysis and gene set analysis were used to compare groups with validation by qPCR. Stress resulted in enrichment of genes sets related to fear response, oxygen carrying capacity and NMDA receptor synthesis. Morphine downregulated gene sets related to immune function. Stress plus morphine resulted in enrichment of mitochondrial electron transport gene sets, and down-regulation of gene sets related to brain development and growth. We conclude that neonatal stress alone influences hippocampal gene expression, morphine alters a subset of stress-related changes in gene expression and influences other gene sets. Stress plus morphine show interaction effects not present with either stimulus alone. These changes may alter neurodevelopment.
Effects of neonatal stress and morphine on murine hippocampal gene expression.
Sex, Specimen part, Treatment
View Samples