Project description:Non-coding RNAs (ncRNAs) are essential components in cellular machineries for translation and splicing. In addition to their housekeeping functions, ncRNAs are involved in cell type-specific regulation of translation, mRNA stability, genome structure and accessibility. To decipher their functions in different cell types, a method to comprehensively quantify them in a sensitive manner is highly desirable. Using miRNA as an example, we showed that cDNA from total RNA could be amplified and specifically detected from a few cells within a single tube. The sensitivity of the system was maximized by avoiding purification from cell lysis to amplified cDNA and by optimizing the buffer conditions. With 100 human embryonic stem cells (hESCs) and their differentiated endothelial cells as input for high-throughput sequencing, the single-tube amplification (STA) system revealed both well-known and other miRNAs selectively enriched in each cell type. The selective enrichment of the miRNAs was further verified by qPCR with 293FT cells and a human induced pluripotent stem cell (hiPSC) line. In addition, the STA system was capable of detecting miRNA expression down to single cells, albeit with some loss of sensitivity and power. Finally, the detection of other non-miRNA transcripts indicated that the STA target was not limited to miRNA, but extended to other ncRNAs and mRNAs as well. Overall, STA offered a simple and extremely sensitive way to collect the quantitative miRNA and other RNA information from individual cells. Grant ID: MOST-104-2314-B-006-038-MY3 Funding source: Ministry of Science and Technology, Taiwan Grantee First Name: Po-Min Grantee Last Name: Chiang
Project description:In the present study we investigated the structure of MYCN amplifications, examples of both dmin and hsr, in eight neuroblastoma (NB) and two small cell lung carcinoma (SCLC) cell lines. Ten cell lines were analyzed for gene amplification: STA-NB3 (NB), STA-NB4 (NB), STA-NB8 (NB), STA-NB10DM (NB), STA-NB10HSR (NB), STA-NB13 (NB), STA-NB15 (NB), SK-N-BE (NB), GLC8 (SCLC), GLC14 (SCLC). NimbleGen human reference sample was used as reference DNA.
Project description:High reproducibility with TaqMan microRNA array (qPCR-array) was demonstrated by comparing replicate results from the same RNA sample. Pre-amplification of the miRNA cDNA improved sensitivity of the qPCR-array and increased the number of detectable miRNAs. Furthermore, the relative expression levels of miRNAs were maintained after pre-amplification. When the performance of qPCR-array and microarrays were compared using different aliquots of the same RNA, a low correlation between the two methods (r = -0.443) indicated considerable variability between the two assay platforms. Higher variation between replicates was observed in miRNAs with low expression in both assays. Finally, a higher false positive rate of differential miRNA expression was observed using the microarray compared to the qPCR-array.
Project description:This study corresponds to a re-analysis and meta-analysis of the five transcriptomic studies related to spontaneous tolerance to renal allograft in human. It examines the transcriptome of peripheral blood samples from six distinct clinical groups: healthy volunteers (HV); tolerant patients (TOL); stable patients on minimal immunosuppression (MIS) or maintained on classical immunosuppressive therapy (STA); patients showing either signs of chronic rejection (CR) or acute rejection (AR). The initial studies are the following: -Study 1 from Braud C. et al. (J Cell Biochem., 2008) published under GEO accession number GSE47755 and comprising 250 unique samples (8 HV; 21 TOL; 190 STA; 31 CR). -Study 2 from Brouard S. et al. (Proc Natl Acad Sci U S A., 2007) published under GEO accession number GSE47683 and comprising 67 unique samples (8 HV; 12 TOL; 10 MIS; 12 STA; 11 CR; 14 AR). - Study 3 from Lozano JJ. et al. (Am J Transplant., 2011) published under GEO accession number GSE22707 and comprising 42 unique samples (6 HV; 12 TOL; 12 STA; 12 CR). - Study 4 from Newell KA. et al. (J Clin Invest., 2010) published under GEO accession number GSE22229 and comprising 58 unique samples (12 HV; 19 TOL; 27 STA). - Study 5 from Sagoo P. et al. (J Clin Invest. 2010) published under GEO accession number GSE14655 and comprising two distinct cohorts of patients. The IOT (“Indices of Tolerance”) cohort (5a) corresponds to a European group of patients and totalizes 74 unique samples (8 HV; 10 TOL; 11 MIS; 36 STA; 9 CR). The ITN (“Immune Tolerance in Transplantation”) cohort (5b) corresponds to an American group of patients and totalizes 105 unique samples (20 HV; 22 TOL; 11 MIS; 34 STA; 18 CR). The final data matrix corresponds to the combination of the data from the five independent studies and examines the expression of 1846 meta-genes (MG) across 596 unique blood samples. The 1846 meta-genes correspond to the genes being measured across the five datasets and form a virtual microarray platform (TOL-HUMAN-G1846). The 596 examined samples can be divided into 62 HV, 96 TOL, 32 MIS, 311 STA, 81 CR, and 14 AR.
Project description:To correlate gene expression profiles to fundamental biological processes such as cell growth, differentiation and migration, it is essential to work at the single cell level. Gene expression analysis always starts with the relatively low efficient reverse transcription (RT) of RNA into complementary DNA (cDNA), an essential step as unprocessed RNAs will not be analyzed further. In this paper, we present a novel method for RT that uses microfluidics to manipulate nanoliter volumes. We compare our method to conventional protocols performed in microliter volumes. More specifically, reverse transcription was performed either in a poly-dimethylsiloxane (PDMS) rotary mixer or in a tube, using single cell amount of mouse brain RNA (10 pg), and was followed by a template-switching PCR (TS-PCR) amplification step. We demonstrate that, using the microfluidic protocol, 74% of the genes expressed in mouse brain were detected, while only 4% were found with the conventional approach. We next profiled single neuronal progenitors. Using our microfluidic approach, i.e. performing cell capture, lysis and reverse transcription on-chip followed by TS-PCR amplification in tube, a mean of 5000 genes were detected in each neuron, which corresponds to the expected number of genes expressed in a single cell. This demonstrates the outstanding sensitivity of the microfluidic method. Keywords: Single cell, transcriptome, PDMS, microfluidic, reverse-transcription (RT), template-switching, lab-on-a-chip
Project description:Only a subset of melanoma patients has evidence for spontaneous T cell infiltration into tumor sites, previously associated with clinical responses. However, the molecular mechanisms explaining absence of a T cell response are not yet defined. Analyses of human melanoma metastases have revealed that T cell signature low tumors show alterations in the Wnt/b-catenin signaling pathway. We utilized an inducible mouse model driven by inducible BrafV600E and PTEN-deletion, with or without active b-catenin (CAT-STA) to test if tumor intrinsic active b-catenin can block anti-tumor immunity. While Braf/PTEN melanomas showed presence of a T cell infiltrate, T cells were nearly completely eliminated in tumors expressing active b-catenin. Adoptive transfer experiments revealed defective T cell priming when tumors expressed active b-catenin. Analysis of the antigen-presenting cell compartment revealed a selective decrease in the CD103+ DC subset within the tumor microenvironment, which could be associated with b-catenin depended inhibition of expression of the chemokine CCL4 within tumor cells. Here we used 3 mice of each genotype BrafV600E/PTEN-/- and BrafV600E/PTEN-/-/Cat-STA and compared their gene-expression profiles. we used 3 mice of each genotype BrafV600E/PTEN-/- and BrafV600E/PTEN-/-/Cat-STA and compared their gene-expression profiles.
Project description:BACKGROUND: Development of the neural tube is a highly orchestrated process relying on precise, spatio-temporal expression of numerous genes as well as hierarchies of signal transduction and gene regulatory networks. Disruption of expression of a number of genes participating in these networks is believed to underlie developmental anomalies such as neural tube defects (NTDs) resulting from anomalous neural tube morphogenesis. MicroRNAs (miRNAs), a large family of noncoding RNAs, have been shown to function as gene silencers, and thus, are key modulators of cell and tissue differentiation. To elucidate potential roles of miRNAs in murine neural tube development, miRNA gene expression profiling has been utilized in the current study, to garner novel and in-depth knowledge on the expression and regulation of genes encoding miRNAs as well as their potential target genes governing maturation of the mammalian neural tube. METHODS: With the aim of identifying differentially expressed miRNAs during mammalian neural tube ontogenesis, miRNA expression profiles from gestation day (GD) -8.5, -9.0 and -9.5 murine neural tube tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. Gene expression changes observed in microarray analysis were verified by TaqManTM quantitative Real-Time PCR. clValid R package and the UPGMA (hierarchical) clustering method were utilized for cluster analysis of the microarray data. Functional associations among selected miRNAs were examined exploiting Ingenuity Pathway Analysis. RESULTS: Expression of approximately 12% of the 609 murine miRNA genes examined was detected in murine neural tube tissues from GD -8.5, -9.0 and -9.5. Clustering analysis revealed several developmentally regulated clusters among these expressed genes. MicroRNA target analysis enabled identification of a panoply of protein-coding target genes of the differentially expressed miRNAs within such clusters. Interestingly, many of these target genes have been shown to be associated with vital cellular processes such as cell proliferation, cell adhesion, cell migration, differentiation, apoptosis and epithelial-mesenchymal transformation, all of which are essential for normal neural tube development. Utilization of Ingenuity Pathway Analysis (IPA; Ingenuity Systems) allowed identification of interactive biological networks connecting differentially expressed miRNAs and their target genes highlighting functional relationships. CONCLUSIONS: In the present study, a unique gene expression signature of a range of miRNAs in embryonic neural tube tissue was delineated. Analysis of miRNA target genes and gene interaction pathways emphasized that expression of numerous protein-encoding genes, indispensable for normal neural tube morphogenesis, may be regulated by specific miRNAs.
Project description:The pluripotency of mouse embryonic stem cells (ESC) and induced-pluripotent stem cells (iPSC) can be maintained by feeder cells, which secrete Leukemia Inhibitory Factor (LIF). We found that feeder cells provide a relatively low concentration (25 unit/ml) of LIF, which is insufficient to maintain the ESC/iPSC pluripotency in feeder free conditions. In order to identify additional factors involved in the maintenance of pluripotency, we carried out a global transcript expression profiling of mouse iPSC cultured on feeder cells and in feeder-free (LIF-treated) conditions. This identified 17 significantly differentially expressed genes (adjusted p-value<0.05) including 7 chemokines over-expressed in iPSC grown on feeder cells. Ectopic expression of these chemokines in iPSC revealed that CC chemokine ligand 2 (Ccl2) induced the key transcription factor genes for pluripotency, Klf4, Nanog, Sox2 and Tbx3. Further, addition of recombinant Ccl2 protein drastically increased the number of Nanog-GFP-positive iPSC grown in low LIF feeder free conditions. Interestingly, this effect was not observed in the absence of LIF. We further revealed that pluripotency promotion by Ccl2 is mediated by activating the Stat3-pathway followed by Klf4 up-regulation. We demonstrated that Ccl2 mediated increased pluripotency is independent of PI3K and MAPK pathways and that Tbx3 may be directly up-regulated by Klf4. Overall, Ccl2 cooperatively activates the Stat3-pathway with LIF in feeder free condition to maintain pluripotency for ESC/iPSC. Total RNAs were purified from feeder cells (as a reference sample), iPSC grown on feeder cells and iPSC grown in feeder-free condition in triplicates and applied to the arrays. iPSC grown on feeder cells were separated mechanically from the feeder layer to minimize feeder cell contamination.
Project description:Genome-wide profiling of copy number alterations and DNA methylation in single cells could enable detailed investigation into the genomic and epigenomic heterogeneity of tumor populations. However, current methods to do this require complex sample processing and cleanup steps, lack consistency, or are biased in their genomic representation. Here, we describe a novel single-tube enzymatic method, DNA Analysis by Restriction Enzyme (DARE), to perform deterministic whole genome amplification while preserving DNA methylation information. This method was evaluated on low amounts of DNA and single cells, and provides accurate copy number aberration calling and representative DNA methylation measurement across the whole genome. Single cell DARE is an attractive and scalable approach for concurrent genomic and epigenomic characterization of cells in a heterogeneous population.
Project description:BACKGROUND: Development of the neural tube is a highly orchestrated process relying on precise, spatio-temporal expression of numerous genes as well as hierarchies of signal transduction and gene regulatory networks. Disruption of expression of a number of genes participating in these networks is believed to underlie developmental anomalies such as neural tube defects (NTDs) resulting from anomalous neural tube morphogenesis. MicroRNAs (miRNAs), a large family of noncoding RNAs, have been shown to function as gene silencers, and thus, are key modulators of cell and tissue differentiation. To elucidate potential roles of miRNAs in murine neural tube development, miRNA gene expression profiling has been utilized in the current study, to garner novel and in-depth knowledge on the expression and regulation of genes encoding miRNAs as well as their potential target genes governing maturation of the mammalian neural tube. METHODS: With the aim of identifying differentially expressed miRNAs during mammalian neural tube ontogenesis, miRNA expression profiles from gestation day (GD) -8.5, -9.0 and -9.5 murine neural tube tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. Gene expression changes observed in microarray analysis were verified by TaqManTM quantitative Real-Time PCR. clValid R package and the UPGMA (hierarchical) clustering method were utilized for cluster analysis of the microarray data. Functional associations among selected miRNAs were examined exploiting Ingenuity Pathway Analysis. RESULTS: Expression of approximately 12% of the 609 murine miRNA genes examined was detected in murine neural tube tissues from GD -8.5, -9.0 and -9.5. Clustering analysis revealed several developmentally regulated clusters among these expressed genes. MicroRNA target analysis enabled identification of a panoply of protein-coding target genes of the differentially expressed miRNAs within such clusters. Interestingly, many of these target genes have been shown to be associated with vital cellular processes such as cell proliferation, cell adhesion, cell migration, differentiation, apoptosis and epithelial-mesenchymal transformation, all of which are essential for normal neural tube development. Utilization of Ingenuity Pathway Analysis (IPA; Ingenuity Systems) allowed identification of interactive biological networks connecting differentially expressed miRNAs and their target genes highlighting functional relationships. CONCLUSIONS: In the present study, a unique gene expression signature of a range of miRNAs in embryonic neural tube tissue was delineated. Analysis of miRNA target genes and gene interaction pathways emphasized that expression of numerous protein-encoding genes, indispensable for normal neural tube morphogenesis, may be regulated by specific miRNAs. Time-course experiment (Developmental Stages), ICR mice embryos on gestational days (GD) 8.5, 9.0 and 9.5. Biological replicates: For each day of gestation, 3 independent pools of 15 to 20 staged embryos were used to procure embryonic orofacial tissues for preparation of 3 distinct pools of RNA that were independently processed and applied to individual miRXplore™ microRNA Microarray chips (Miltenyi Biotec GmbH). Technology: 2-color spotted cDNA, Hy5 (experimental sample) vs. Hy3 (control - miRXplore Universal Reference).