Project description:The cellular composition of heterogeneous samples can be predicted from reference gene expression profiles that represent the homogeneous, constituent populations of the heterogeneous samples. However, existing methods fail when the reference profiles are not representative of the constituent populations. We developed PERT, a new probabilistic expression deconvolution method, to address this limitation. PERT was used to deconvolve cellular composition of variably sourced and treated heterogeneous human blood samples. Our results indicate that even after correcting batch effects, cells presenting the same cell surface antigens display different transcriptional programs when they are uncultured versus culture-derived. Given gene expression profiles of culture-derived heterogeneous samples and profiles of uncultured reference populations, PERT was able to accurately recover proportions of pure populations composing the heterogeneous samples. We anticipate that PERT will be widely applicable to expression deconvolution problems using profiles from reference populations that vary from the corresponding constituent populations in cellular state but not cellular identity. Gene expression microarray to examine transcriptome variations between uncultured and culture-deried blood cells of the same phenotype as defined by the on and off expression of antigens.
Project description:The cellular composition of heterogeneous samples can be predicted from reference gene expression profiles that represent the homogeneous, constituent populations of the heterogeneous samples. However, existing methods fail when the reference profiles are not representative of the constituent populations. We developed PERT, a new probabilistic expression deconvolution method, to address this limitation. PERT was used to deconvolve cellular composition of variably sourced and treated heterogeneous human blood samples. Our results indicate that even after correcting batch effects, cells presenting the same cell surface antigens display different transcriptional programs when they are uncultured versus culture-derived. Given gene expression profiles of culture-derived heterogeneous samples and profiles of uncultured reference populations, PERT was able to accurately recover proportions of pure populations composing the heterogeneous samples. We anticipate that PERT will be widely applicable to expression deconvolution problems using profiles from reference populations that vary from the corresponding constituent populations in cellular state but not cellular identity. Gene expression microarray to examine transcriptome variations between uncultured and culture-deried blood cells of the same phenotype as defined by the on and off expression of antigens. Fresh human umbilical cord blood-derived and serum free culture-derived colony-forming unit-monocytes (CFU-M) and megakaryocytes (MEGA) were compared respectively
Project description:The human liver contains multiple cell types whose epigenetic patterns are undetermined. We examined the promoter methylome of purified and uncultured hepatic stellate cells (HSCs), hepatocytes (HEPs) and liver sinusoidal endothelial cells (LSECs), by methylated DNA immunoprecipitation (MeDIP) and array hybridization. Uncultured HSCs, LSECs and Heps show ~7000-8000 methylated promoters, with 60-70% similarity between all cell types. GO analysis for commonly methylated genes reveals involvement in germ cell development, segregating germ-line from somatic lineage methylation. HSCs, LSECs and HEPs also contain ~500-1000 uniquely methylated promoters; these are implicated in signaling and biosynthetic processes (HSCs), lipid transport and metabolism (LSECs), and chromatin assembly (HEPs). The promoter methylome of culture-activated HSCs deviates from that of their uncultured (quiescent) counterparts. HSC culture-induced activation also enhances methylation differences between individual donors; however this does not necessarily relate to changes in gene expression. HSc activation results in a net gain of promoter DNA methylation, despite the demethylation and de novo methylation of thousands of promoters. Our data provide to our knowledge the first genome-wide maps of promoter DNA methylation in human purified and uncultured liver cell types. Although methylation profiles are largely similar between HSCs, LSECs and hepatocytes, the detection of cell type-specific methylation patterns suggests a differential epigenetic programming of these cell types in the liver.
Project description:The human liver contains multiple cell types whose epigenetic patterns are undetermined. We examined the promoter methylome of purified and uncultured hepatic stellate cells (HSCs), hepatocytes (HEPs) and liver sinusoidal endothelial cells (LSECs), by methylated DNA immunoprecipitation (MeDIP) and array hybridization. Uncultured HSCs, LSECs and Heps show ~7000-8000 methylated promoters, with 60-70% similarity between all cell types. GO analysis for commonly methylated genes reveals involvement in germ cell development, segregating germ-line from somatic lineage methylation. HSCs, LSECs and HEPs also contain ~500-1000 uniquely methylated promoters; these are implicated in signaling and biosynthetic processes (HSCs), lipid transport and metabolism (LSECs), and chromatin assembly (HEPs). The promoter methylome of culture-activated HSCs deviates from that of their uncultured (quiescent) counterparts. HSC culture-induced activation also enhances methylation differences between individual donors; however this does not necessarily relate to changes in gene expression. HSc activation results in a net gain of promoter DNA methylation, despite the demethylation and de novo methylation of thousands of promoters. Our data provide to our knowledge the first genome-wide maps of promoter DNA methylation in human purified and uncultured liver cell types. Although methylation profiles are largely similar between HSCs, LSECs and hepatocytes, the detection of cell type-specific methylation patterns suggests a differential epigenetic programming of these cell types in the liver. Determine the promoter DNA methylation pattern of 3 uncultured, reshly isolated, human healthy liver cell types (hepatocytes (HEPs), liver sinusoidal endothelial cells (LSECs) and haptic stellate cells (HSCs), and of HSCs after a 24-h culture-induced activation.
Project description:This SuperSeries is composed of the following subset Series: GSE40829: Expression profiles of lineage-depleted (Lin-) cell and mono-nucleated cell (MNC) samples derived from human umbilical cord blood GSE40830: Expression analysis of uncultured and culture-derived colony forming unit-monocytes and megakaryocytes Refer to individual Series
Project description:Antimicrobial resistance is a leading mortality factor worldwide. Here we report the discovery of clovibactin, a new antibiotic, isolated from uncultured soil bacteria. Clovibactin efficiently kills drug-resistant Gram-positivebacterial pathogens without detectable resistance. Using biochemical assays,solid-state NMR, and atomic force microscopy, we dissect its mode of action. Clovibactin blocks cell wall synthesis by targeting pyrophosphate of multiple essential peptidoglycan precursors (C55PP, Lipid II, LipidWTA). Clovibactin uses anunusual hydrophobic interface to tightly wrap aroundpyrophosphate, butbypasses the variable structural elements of precursors, accounting for the lack of resistance. Selective and efficient target binding is achieved by the sequestration of precursors into supramolecular fibrils that only form on bacterial membranes that contain lipid-anchored pyrophosphate groups.Uncultured bacteria offer a rich reservoir of antibiotics with new mechanisms of action that could replenish the antimicrobial discovery pipeline.