Transcription profiling of rat kidney and liver from several different strains to determine the effects of hyperglycaemia and genetic background difference on gene expression
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ABSTRACT: Effects of hyperglycaemia and genetic background differences on renal and hepatic gene expression
Project description:BACKGROUND: Nitrogen is an essential element for bacterial growth and an important component of biological macromolecules. Consequently, responding to nitrogen limitation is critical for bacterial survival and involves the interplay of signalling pathways and transcriptional regulation of nitrogen assimilation and scavenging genes. In the soil dwelling saprophyte Mycobacterium smegmatis the OmpR-type response regulator GlnR is thought to mediate the transcriptomic response to nitrogen limitation. However, to date only ten genes have been shown to be in the GlnR regulon, a vastly reduced number compared to other organisms. RESULTS: We investigated the role of GlnR in the nitrogen limitation response and determined the entire GlnR regulon, by combining expression profiling of M. smegmatis wild type and glnR deletion mutant, with GlnR-specific chromatin immunoprecipitation and high throughput sequencing. We identify 53 GlnR binding sites during nitrogen limitation that control the expression of over 100 genes, demonstrating that GlnR is the regulator controlling the assimilation and utilisation of nitrogen. We also determine a consensus GlnR binding motif and identify key residues within the motif that are required for specific GlnR binding. CONCLUSIONS: We have demonstrated that GlnR is the global nitrogen response regulator in M. smegmatis, directly regulating the expression of more than 100 genes. GlnR controls key nitrogen stress survival processes including primary nitrogen metabolism pathways, the ability to utilise nitrate and urea as alternative nitrogen sources, and the potential to use cellular components to provide a source of ammonium. These studies further our understanding of how mycobacteria survive nutrient limiting conditions. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-143]
Project description:Context : Non Functioning Pituitary Adenomas (NFPAs), although typically benign, may be locally invasive. Few datas are currently available related to the molecular process of invasion in sporadic pituitary adenomas. Markers of invasiveness, important for helping the clinician in the therapeutic strategy particularly in the decision for adjuvant radiotherapy, are currently lacking. Objective: Evaluate if invasive NFPAs display a specific expression profile compared with non invasive tumors. Methods: To address this issue, we selected 40 NFPAs (38 of the gonadotroph type) and classified them as invasive (n=22) or non invasive (n=18) on the basis of MRI and surgical findings. Then we performed pangenomic analysis based on Agilent Human Whole genome Gene Expression oligonucleotide microarray (44k) Expression in order to identify genes differentially expressed between invasive and non invasive NFPA. Experiements are made in dual color with tumor samples labelled in cyanine 5 and a pool of all tumors labelled in cyanine 3.The expressions of some genes identified by microarray screening were confirmed by real-time quantitative RT-PCR. The selection of genes was made on the basis of Ingenuity networks and degree of upregulation between invasive and non invasive tumors. Moreover, some genes of interest already described in the literature were added to the analysis. Results: Prediction class analysis showed that 346 genes discriminated between invasive and non invasive NFPAs (p<0.001); 233 were up- and 113 were down-regulated between the two groups. We then tested On the basis of Ingenuity networks and degree of upregulation between invasive and non invasive tumors, a set of eight genes, including MYO5A, IGFBP5, FLT3, NFE2L1, PTTG, MMP9, NCAM and NR1H3, was tested in quantitative PCR analysis and. Results confirmed those obtained in microarrays results.analysis. At the protein level, Myosin 5A (MYO5A) demonstrated stronger immunostaining in invasive NFPAs compared to non invasive NFPAs. Conclusions: We propose a molecular signature of eight genes of grossly invasive NFPAs as compared with non invasive tumors: The product of one of these genes, MYO5A, may be a useful marker of invasive process in tumoral specimens. The role of these genes in the invasiveness process and as prognostic markers of pituitary adenomas needs to be confirmedinvestigated. Method: Microarray analyses the transcriptome of 22 invasive Non Functional Pituitary Adenomas (NFPAs) and 18 non invasive NFPAs in dual color (each sample labelled in cyanine 5 and a pool of all tumors labelled in cyanine 3).
Project description:Two different strains of Aedes aegypti mosquito, Moyo-in-dry and Moyo-S, are profiled for their response through time to infection with Dengue 2 virus. Expression is measured using a two-colour custom spotted cDNA array. A mixed strain uninfected sample is hybridized as the reference.
Project description:Characterize the genes deregulated in CD34 positive cells from peripheral blood of FPD/AML patients harbouring two different RUNX1 mutations. RUNX1 (also called AML1), a DNA-binding subunit of the CBF transcription factor family, is a master regulatory gene in hematopoiesis and acts as a tumour suppressor. Heterozygous germ line alterations in RUNX1 lead to a familial platelet disorder with a propensity to develop acute myeloid leukemia (FPD/AML). Although RUNX1 abnormalities per se are not sufficient to induce full-blown leukemia in FPD, this pathology represents a valuable model to understand how RUNX1 germ line mutations predispose to acquisition of additional genetic changes leading to leukemia transformation. To investigate how RUNX1 may predispose to leukemia, we performed a comparative study between two pedigrees harbouring different RUNX1 mutations, one associated with only thrombocytopenia (R139stop) and the other leading to thrombocytopenia and leukemic predisposition (R174Q).
Project description:Mutations in the tumor suppressor gene PTCH1 are responsible for Gorlin syndrome, or nevoid basal cell carcinoma syndrome (NBCCS). NBCCS causes predisposition to basal cell carcinoma (BCC), the commonest cancer in adult human. In the general population BCC develop almost exclusively in sun-exposed area of the skin (Buettner PG, Raasch BA (1998) Int J Cancer 78: 587-593). In contrast, and, intriguingly, NBCCS BCCs are observed in both sun-protected and sun-exposed areas. Interestingly, our previous studies have shown that both fibroblasts and keratinocytes from NBCCS patients exhibit normal nucleotide excision repair of UVB-induced DNA lesions and survival capacities following a single UVB irradiation (Brellier F, Valin A, et al. (2008) Br J Dermatol.). These data suggest that sun UV are far from being the only etiologic factor of BCC in NBCCS patients. In this study we aimed at documenting the possible role of NBCCS fibroblasts in BCC development in NBCCS patients. Thus, the genome expression of NBCCS primary fibroblasts cultured in a dermal equivalent was compared to the one of control fibroblasts under the same circumstances.
Project description:Characterize the genes regulated by MKL1/SRF complex in human megakaryocytes (MKs) derived from cord blood or cytapheresis : Using a knock down approach by small interference of MKL1 in MK progenitors, we observed a decrease in the percentage of cells with actin polymerization after adhesion on various substrates, an increase of mean ploidy level and apoptosis. Furthermore, MKL1 inhibition induced a major defect in pro-platelet formation and MKs migration. These results clearly demonstrate that MKL1 is involved in the cytoskeleton organization and maturation of MKs as well as in platelet formation. The goal of gene profiling was to identify new potential MKL1/SRF targets the expression level of which was down regulated after MKL1 inhibition: Human CD34+ cells isolated from cord blood or cytapheresis were transduced by a control lentivirus (designed as SCR; scramble) or by the lentivirus encoding for shRNA of MKL1 (designed as shMKL1) both containing a GFP expressed under the control of PGK promoter. The cells were than grown in serum free medium supplemented by thrombopoietin leading to a generation of megakaryocytes. At day 9 of culture (80% of MKs), the GFP positive cells were sorted, RNAs were extracted and submitted to hybridization as described in annex protocols. Two lists of genes (one for cord blood samples and one for cytapheresis samples) deregulated after the repression of MKL1 were done comparing the intensity of hybridization between SCR and shMKL1 samples. The common list of genes deregulated in MKs from cord blood and cytapheresis after the repression of MKL1 was than generated.
Project description:Differentiating agents have been proposed to overcome the impaired cellular differentiation in acute myeloid leukemia (AML). However, only the combinations of all-trans retinoic acid or arsenic trioxide with chemotherapy have been successful, and only in treating acute promyelocytic leukemia (also called AML3). Here we showed that iron homeostasis is an effective target in the treatment of AML. Iron chelating therapy induces the differentiation of leukemia blasts and normal bone marrow precursors into monocytes/macrophages in a manner involving modulation of reactive oxygen species expression and the activation of mitogen-activated protein kinases (MAPK). Thirty percent of the genes most strongly induced by iron deprivation are also targeted by vitamin D3 (VD), a well-known differentiating agent. Iron chelating agents induce expression and phosphorylation of the VD receptor, and iron deprivation and VD act synergistically. VD magnifies activation of MAPK JNK and the induction of VD receptor target genes. When used to treat one AML patient refractory to chemotherapy, the combination of iron chelating agents and VD resulted in reversal of pancytopenia and blast differentiation. We propose that iron availability modulates myeloid cell commitment, and that targeting this cellular differentiation pathway together with conventional differentiating agents provides new therapeutic modalities for AML. This study presents 8 arrays 4x44K Agilent.