Project description:Since the worldwide increase in obesity represents a growing challenge for health care systems, new approaches are needed to effectively treat obesity and its associated diseases. One prerequisite for advances in this field is the identification of genes involved in adipogenesis and/or lipid storage. 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. The primary screen showed that 459 genes affected adipogenesis and/or lipid accumulation after knock-down. Out of these hits, 333 could be validated in a secondary screen using independent siRNAs and 110 genes were further regulated on the gene expression level during adipogenesis. Assuming that these genes are involved in neutral lipid storage and/or adipocyte differentiation, we performed InCell-Western analysis for the most striking hits to distinguish between the two phenotypes. Beside well known regulators of adipogenesis and neutral lipid storage (i.e. PPARγ, RXR, Perilipin A) the screening revealed a large number of genes which have not been previously described in the context of fatty tissue biology such as axonemal dyneins. Five out of ten axonemal dyneins were identified in our screen and quantitative RT-PCR-analysis revealed that these genes are expressed in preadipocytes and/or maturing adipocytes. Finally, to show that the genes identified in our screen are per se druggable we performed a proof of principle experiment using an antagonist for HTR2B. 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: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: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:BACKGROUND:The level of fat deposition in carcass is a crucial factor influencing meat quality. Guangling Large-Tailed (GLT) and Small-Tailed Han (STH) sheep are important local Chinese fat-tailed breeds that show distinct patterns of fat depots. To gain a better understanding of fat deposition, transcriptome profiles were determined by RNA-sequencing of perirenal, subcutaneous, and tail fat tissues from both the sheep breeds. The common highly expressed genes (co-genes) in all the six tissues, and the genes that were differentially expressed (DE genes) between these two breeds in the corresponding tissues were analyzed. RESULTS:Approximately 47 million clean reads were obtained for each sample, and a total of 17,267 genes were annotated. Of the 47 highly expressed co-genes, FABP4, ADIPOQ, FABP5, and CD36 were the four most highly transcribed genes among all the known genes related to adipose deposition. FHC, FHC-pseudogene, and ZC3H10 were also highly expressed genes and could, thus, have roles in fat deposition. A total of 2091, 4233, and 4131 DE genes were identified in the perirenal, subcutaneous, and tail fat tissues between the GLT and STH breeds, respectively. Gene Ontology (GO) analysis showed that some DE genes were associated with adipose metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that PPAR signaling pathway and ECM-receptor interaction were specifically enriched. Four genes, namely LOC101102230, PLTP, C1QTNF7, and OLR1 were up-regulated and two genes, SCD and UCP-1, were down-regulated in all the tested tissues of STH. Among the genes involved in ECM-receptor interaction, the genes encoding collagens, laminins, and integrins were quite different depending on the depots or the breeds. In STH, genes such as LAMB3, RELN, TNXB, and ITGA8, were identified to be up regulated and LAMB4 was observed to be down regulated. CONCLUSIONS:This study unravels the complex transcriptome profiles in sheep fat tissues, highlighting the candidate genes involved in fat deposition. Further studies are needed to investigate the roles of the candidate genes in fat deposition and in determining the meat quality of sheep.

Dataset Information

Investigation of allele-specific expression of genes involved in adipogenesis and lipid metabolism suggests complex regulatory mechanisms of PPARGC1A expression in porcine fat tissues.

Publications

Investigation of allele-specific expression of genes involved in adipogenesis and lipid metabolism suggests complex regulatory mechanisms of PPARGC1A expression in porcine fat tissues.

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