Project description:Discovery of small molecules that correct gene networks dysregulated in human disease may allow identification of therapies that treat disease at its fundamental basis by leveraging mechanism-based data. Here, we report the first broad gene network-based drug screen, which led to discovery of a drug candidate that effectively treats aortic valve disease in an animal model. We previously reported haploinsufficiency of NOTCH1 (N1) as a genetic cause of human aortic valve thickening and calcification, the third most common form of heart disease, and described the resulting gene network dysregulation in human induced pluripotent stem cell (iPSC)-derived endothelial cells (ECs). We exposed isogenic N1+/+ or N1+/– iPSC-derived ECs to each of 1595 small molecules or control and developed a machine learning approach that accurately distinguished WT or N1-haploinsufficient cells based on expression of 119 genes assayed by targeted RNA-sequencing. 9 small molecules corrected the gene network of N1+/– ECs sufficiently to be classified as WT. Among hits tested in vivo, the estrogen receptor-related alpha inverse agonist XCT790 significantly reduced aortic valve thickening, calcification, and stenosis in N1-haploinsufficient mice with shortened telomeres, which model the range of age-dependent cardiac disease observed in humans. This strategy, made feasible by human iPSC technology, next generation sequencing approaches, and machine learning, may represent a more effective path for drug discovery compared to conventional screening approaches.
Project description:This SuperSeries is composed of the following subset Series: GSE37611: Effect of small molecules on activated astrocytes GSE37612: Effect of small molecules on activated BV2 microglia cell line Refer to individual Series
Project description:Unique Molecular Identifiers (UMIs) are random oligonucleotide barcodes sequences? that are critical for the removal of PCR amplification biases within both bulk and single-cell sequencing experiments. However, the impact that PCR and sequencing errors have on the accuracy of generating absolute counts of RNA molecules is underappreciated. We demonstrate that PCR errors and not sequencing errors are the main source of inaccuracy in sequencing data and that the use of UMIs synthesized with homotrimeric nucleoside building blocks provides a solution to pinpoint and remove errors, allowing absolute counting of sequenced molecules.
Project description:Unique Molecular Identifiers (UMIs) are random oligonucleotide barcodes sequences? that are critical for the removal of PCR amplification biases within both bulk and single-cell sequencing experiments. However, the impact that PCR and sequencing errors have on the accuracy of generating absolute counts of RNA molecules is underappreciated. We demonstrate that PCR errors and not sequencing errors are the main source of inaccuracy in sequencing data and that the use of UMIs synthesized with homotrimeric nucleoside building blocks provides a solution to pinpoint and remove errors, allowing absolute counting of sequenced molecules.
Project description:Small molecules directly binding DNA in cells destabilized chromatin what is "sensed" by histone chaperone FACT. FACT binds regions with destabilized chromatin via "c-trapping". DNA-targeting small molecules are widely used for anticancer therapy based on their ability to induce cell death, presumably via DNA damage. DNA in the eukaryotic cell is packed into chromatin, a highly-ordered complex of DNA, histones, and non-histone proteins. These agents perturb chromatin organization. However, the mechanisms, consequences, and impact of the alterations of chromatin structure in relation to their anti-cancer activity is unclear because it is difficult to separate DNA damage and chromatin damage in cells. We recently demonstrated that curaxins, small molecules with broad anticancer activity, bind DNA without causing detectable DNA damage by interfering with histone/DNA interactions and destabilizing the nucleosome. Chromatin unfolding caused by curaxins is sensed by histone chaperone FACT. FACT binds unfolded nucleosomes, which leads to chromatin trapping or c-trapping. In this study, we investigated whether other DNA-targeting small molecules disturb chromatin and cause c-trapping. We found that only compounds directly binding DNA induce chromatin damage and c-trapping. Chromatin damage may occur in the absence of DNA damage and is dependent on the mechanism of compound binding to DNA and its ability to bind chromatinized DNA in cells. We show that FACT is sensitive to a plethora of nucleosomes perturbations induced by DNA-binding small molecules, including displacement of the linker histone, eviction of core histones, and accumulation of negative supercoiling. Most importantly, the cytotoxicity of DNA-binding small molecules correlates with their ability to cause chromatin damage, but not DNA damage.
Project description:au14-11_levure - study of a kinetic answer - Effect of a mixture of molecules stemming from industrial process - Cells were submitted to products and harveted at time 0, 1 4 and 4 hrs