Project description:Since the worldwide increase in obesity represents a growing challenge for the health care systems, new approaches are needed to treat obesity and associated disease effectively. The food intake is primarily stored in the adipose tissue and therefore this organ is in focus to develop new anti-obesity treatments. To provide a systematic analysis of genes that regulate adipose tissue biology and to establish a target-oriented compound screening, we performed a high throughput siRNA screen with primary (pre)adipocytes, using a druggable siRNA library targeting 7,784 human genes. Beside well known regulators of adipogenesis and neutral lipid storage (like PPAR?, RXR, Perilipin A) the screening revealed a large number of genes which were not previously described in the context of fatty tissue biology. An enrichment of genes was observed for axonemal dyneins. Five out of ten anxonemal dyneins were identified in our primary screen and retested positive with independent siRNAs and cell-donors. Quantitative RT-PCR- and immunoblot analysis revealed that axonemal dyneins are expressed in preadipocytes and maturing adipocytes. Using microarray analysis, we further characterize the remaining genes identified in our primary screen to determine their expression pattern during adipogenesis. In the course of fat cell differentiation, 149 among the 459 positive genes were regulated on the gene expression level. Assuming that an adipogenesis-specific expression pattern is another independent hind, that these genes are involved in neutral lipid storage and/or adipocyte differentiation, we retested this gene-pool with independent siRNAs and cell donors. Finally, to show that the genes identified are per se druggable we performed a proof of principle experiment using an antagonist for one randomly chosen gene. The results showed a very similar phenotype compared to knock-down experiments proofing the druggability. Thus, we identified new adipogenesis-associated genes and those involved in neutral lipid storage. Moreover, by using a druggable siRNA library the screen data provides a very attractive starting point, to identify anti-obesity compounds targeting the adipose tissue. For microarray analysis, RNA was isolated at 3 different points in time during adipogenesis (day 0, day 3 and day 7 after induction of differentiation). This experiment was carried out with cells obtained from three different donors. No replicates are included for each point in time.
Project description:41 lung adenocarcinoma from never-smokers hybridized on Illumina SNP arrays on 13 HumanCNV370-Quadv3 chips. High-resolution array comparative genomic hybridization analysis of lung adenocarcinoma in 41 never smokers for identification of new minimal common regions (MCR) of gain or loss. The SNP array analysis validated copy-number aberrations and revealed that RB1 and WRN were altered by recurrent copy-neutral loss of heterozygosity.The present study has uncovered new aberrations containing cancer genes. The oncogene FUS is a candidate gene in the 16p region that is frequently gained in never smokers. Multiple genetic pathways defined by gains of MYC, deletions of RB1 and WRN or gains on 7p and 7q are involved in lung adenocarcinoma in never smokers. A 'Cartes d'Identite des Tumeurs' (CIT) project from the French National League Against Cancer (http://cit.ligue-cancer.net) 41 samples hybridized on Illumina SNP arrays. Submitter : Fabien PETEL petelf@ligue-cancer.net . Project leader : Pr Pierre FOURET pierre.fouret@psl.aphp.fr
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Since the worldwide increase in obesity represents a growing challenge for the health care systems, new approaches are needed to treat obesity and associated disease effectively. The food intake is primarily stored in the adipose tissue and therefore this organ is in focus to develop new anti-obesity treatments. To provide a systematic analysis of genes that regulate adipose tissue biology and to establish a target-oriented compound screening, we performed a high throughput siRNA screen with primary (pre)adipocytes, using a druggable siRNA library targeting 7,784 human genes. Beside well known regulators of adipogenesis and neutral lipid storage (like PPAR?, RXR, Perilipin A) the screening revealed a large number of genes which were not previously described in the context of fatty tissue biology. An enrichment of genes was observed for axonemal dyneins. Five out of ten anxonemal dyneins were identified in our primary screen and retested positive with independent siRNAs and cell-donors. Quantitative RT-PCR- and immunoblot analysis revealed that axonemal dyneins are expressed in preadipocytes and maturing adipocytes. Using microarray analysis, we further characterize the remaining genes identified in our primary screen to determine their expression pattern during adipogenesis. In the course of fat cell differentiation, 149 among the 459 positive genes were regulated on the gene expression level. Assuming that an adipogenesis-specific expression pattern is another independent hind, that these genes are involved in neutral lipid storage and/or adipocyte differentiation, we retested this gene-pool with independent siRNAs and cell donors. Finally, to show that the genes identified are per se druggable we performed a proof of principle experiment using an antagonist for one randomly chosen gene. The results showed a very similar phenotype compared to knock-down experiments proofing the druggability. Thus, we identified new adipogenesis-associated genes and those involved in neutral lipid storage. Moreover, by using a druggable siRNA library the screen data provides a very attractive starting point, to identify anti-obesity compounds targeting the adipose tissue.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Insulin resistance and Type 2 Diabetes Mellitus (T2DM) are associated with increased adipocyte size, altered secretory pattern and decreased differentiation of preadipocytes. To identify the underlying molecular processes in preadipocytes of T2DM patients that are a characteristic of the development of T2DM, preadipocyte cell cultures were prepared from subcutaneous fat biopsies of T2DM patients and compared with age- and BMI matched control subjects. Gene expression profiling showed changed expression of transcription factors involved in adipogenesis and in extracellular matrix remodeling, actin cytoskeleton and integrin signaling genes, which indicated decreased capacity to differentiate. Additionally, genes involved in insulin signaling and lipid metabolism were down-regulated, and inflammation/apoptosis was up-regulated in T2DM preadipocytes. The down-regulation of genes involved in differentiation can provide a molecular basis for the reduced adipogenesis of preadipocytes of T2DM subjects, leading to reduced formation of adipocytes in subcutaneous fat depots, and ultimately leading to ectopic fat storage.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.