Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Sensitivity and linear dynamic range of miRNA detection

ABSTRACT: MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. The linear dynamic range and sensitivity of the microarray was measured by hybridizing dilution series of a Universal Reference (UR), an equimolar mixture of synthetic miRNAs. The UR was hybridized with 10,000 to 1 amol of each individual miRNA. Each individual miRNA and 1 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes was fluorescently labelled by 3â ligation. The RNA mix was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool.

ORGANISM(S): synthetic construct

SUBMITTER: Ute Bissels

PROVIDER: E-GEOD-15834 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Absolute quantification of microRNAs by using a universal reference.

Bissels Ute U Wild Stefan S Tomiuk Stefan S Holste Angela A Hafner Markus M Tuschl Thomas T Bosio Andreas A

RNA (New York, N.Y.) 20091027 12

MicroRNAs (miRNAs) are a species of small RNAs approximately 21-23-nucleotides long that have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous PCR-, sequencing-, or hybridization-based methods have been established to identify and quantify miRNAs. Their short length results in a high dynamic range of melting temperatures and therefore impedes a proper selection of detection probes or optimized PCR primers. While mi ...[more]

PMID: 19861428

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Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. The RNA extracted from 7 x 10^ 5 to 1 x 10^ 6 CD34(+)/CD133(-) cells of three different donors was analyzed. 1 µg of respective total RNA was mixed with 2.5 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes and subsequently fluorescently labelled by 3’ ligation. Total RNA mix was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool. The synthetic miRNA pool consisted of 2.5 fmol of each of 954 non redundant miRNAs sequences and miRControl 3 sequences. The array data was normalized by calculating the median of the miRControl 3 present in the CD34(+)/CD133(-) and UR sample. The miRNA amount was calculated with respect to the corresponding miRNA in the UR.

Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. We analyzed to which extend the universal reference can be used as a tool for the relative quantification of miRNAs across multiple experiments. We compared the results of direct hybridizations i.e. sample vs. sample to those of indirect hybridizations i.e. sample vs. UR. For the direct hybridizations, we hybridized 5Âµg liver total RNA vs 5 Âµg brain total RNA (n = 3) and for the indirect hybridization 5 Âµg liver or brain total RNA vs UR (5 fmol/miRNA) (n = 3). We calculated the so-called re-ratios for the UR experiments by dividing the signal ratios of the liver vs. UR array by the respective brain vs. UR array gaining a liver vs. brain re-ratio. Each RNA sample was mixed with 5 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes and subsequently fluorescently labelled. The RNA mix was hybridized in a dual colour approach to microarrays. The mean ratios of all probes were normalized to the median of the ratios detected for the spiked 18 synthetic RNA oligonucleotides reverse complement to miRControl 3 probes.

Project description:MicroRNAs (miRNAs) have been shown to play an important role in many different cellular, developmental, and physiological processes. Accordingly, numerous methods have been established to identify and quantify miRNAs. The shortness of miRNA sequence results in a high dynamic range of melting temperatures and, moreover, impedes a proper selection of detection probes or optimized PCR primers. While miRNA microarrays allow for massive parallel and accurate relative measurement of all known miRNAs, they have so far been less useful as an assay for absolute quantification. Here, we present a microarray based approach for global and absolute quantification of miRNAs. The method relies on an equimolar pool of about 1000 synthetic miRNAs of known concentration which is used as an universal reference and labeled and hybridized in a dual colour approach on the same array as the sample of interest. Each single miRNA is quantified with respect to the universal reference outbalancing bias related to sequence, labeling, hybridization or signal detection method. We demonstrate the accuracy of the method by various spike in experiments. Further, we quantified miRNA copy numbers in liver samples and CD34(+)CD133(-) hematopoietic stem cells. Different probe designs were investigated with respect to sensitivity and selectivity of microarray hybridization. An array with 11 different variants of oligonucleotides for miR-122a and miR-16 was produced. 5 µg of respective total RNA was fluorescently labelled by 3’ ligation. Total RNA was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool. The synthetic miRNA pool consisted of 5 fmol of each of 816 non redundant miRNAs sequences and miRControl 3 sequences. Local background was subtracted from the signal to obtain the net signal intensity and the mean of the net signal intensities of 4 corresponding spots representing the same miRNA was computed for those spots only which were unflagged (empty spots, poor spots, negative spots) and for which the fluorescent intensity of the miRNAs derived from the samples of interest was two-fold the mean background value (2bkg dataset).

Project description:Membrane vesicles released by neoplastic cells into extracellular medium contain potential of carrying arrays of oncogenic molecules including proteins and microRNAs (miRNA). Extracellular (exosome-like) vesicles play a major role in cell-to-cell communication. Thus, the characterization of miRNAs of exosome-like vesicles is imperative in clarifying intercellular signaling as well as identifying disease markers. microarray analysis identified several oncogenic miRNA between the two types vesicles. Exosome-like vesicles were isolated using gradient centrifugation from MCF-7 and MDA-MB 231 cultures. Sample-derived miRNA expression was analyzed on Miltenyi's miRXploreM-bM-^DM-" platform. The RNA was isolated from two replicate samples of MDA-MB231 and MCF7 cell lines. The miRNAs extracted from all four samples were labeled with Hy5 and hybridized against Hy3-labeled Universal Reference miRNA (UR). Candidate miRNAs were identified. In this report, the re-ratios of MDA1 or MDA2 relative to a virtual pool of both MCF7 samples 1 and 2 were used for further analyses. 1- Reratio No. 7 MDA 1 vs MCF7 1+2 reratios of (MDA 1 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970041, (7970039 + 7970040) 2- Reratio No. 8 MDA 2 vs MCF7 1+2 reratios of (MDA 2 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970042, (7970039 + 7970040) Exosome-like vesicles were isolated using gradient centrifugation from MCF-7 and MDA-MB 231 cultures. Sample-derived miRNA expression was analyzed on Miltenyi's miRXploreM-bM-^DM-" platform. The RNA was isolated from two replicate samples of MDA-MB231 and MCF7 cell lines. The miRNAs extracted from all four samples were labeled with Hy5 and hybridized against Hy3-labeled Universal Reference miRNA (UR). Candidate miRNAs were identified. In this report, the re-ratios of MDA1 or MDA2 relative to a virtual pool of both MCF7 samples 1 and 2 were used for further analyses. 1- Reratio No. 7 MDA 1 vs MCF7 1+2 reratios of (MDA 1 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970041, (7970039 + 7970040) 2- Reratio No. 8 MDA 2 vs MCF7 1+2 reratios of (MDA 2 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970042, (7970039 + 7970040)

Project description:BACKGROUND: Orofacial development is a multifaceted process involving precise, spatio-temporal expression of a panoply of genes. MicroRNAs (miRNAs) constitute the largest family of noncoding RNAs involved in gene silencing, and represent critical regulators of cell and tissue differentiation. MicroRNA gene expression profiling is an effective means of acquiring novel and valuable information regarding the expression and regulation of genes, under the control of miRNA, involved in mammalian orofacial development. RESULTS: To identify differentially expressed miRNAs during mammalian orofacial ontogenesis, miRNA expression profiles from gestation day (GD) -12, -13 and -14 murine orofacial tissue were compared utilizing miRXplore™ microarrays from Miltenyi Biotech GmbH. TaqManTM quantitative Real-Time PCR was utilized for validation of gene expression changes. Cluster analysis of the microarray data was conducted with the clValid R package and the UPGMA (hierarchical) clustering method. Functional relationships between selected miRNAs were investigated using Ingenuity Pathway Analysis. Expression of over 26% of the approximately 588 murine miRNA genes examined was detected in murine orofacial tissues from GD 12, 13 and 14. Among these expressed genes several clusters were seen to be developmentally regulated. Differential expression of genes encoding miRNAs within such clusters were shown to target genes encoding proteins involved in cell proliferation, cell adhesion, differentiation, apoptosis and epithelial-mesenchymal transformation, all processes critical for normal orofacial development. Functional relationships between miRNAs differentially expressed were investigated using Ingenuity Pathway Analysis (IPA; Ingenuity Systems). CONCLUSIONS: Using miRNA microarray technology, unique gene expression signatures of hundreds of miRNAs in embryonic orofacial tissue were defined. Gene targeting and functional analysis revealed that the expression of numerous protein-encoding genes, crucial to normal orofacial ontogeny, may be regulated by specific miRNAs. Time-course experiment (Developmental Stages), ICR mice embryos on gestational days (GD) 12, 13 and 14. 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).

Project description:microRNAs, important regulators of cell proliferation and apoptosis, have been shown to be involved in the pathogenesis of acute myeloid leukemia in adulthood AML. However, comprehensive studies in AML of children and adolescents are missing so far. We investigated the miRNA expression profiles of different AML subtypes from 102 pediatric patients in comparison to CD34+ cells from healthy donors and adult AML patients, in order to identify differentially expressed miRNAs. Pediatric samples with core factor binding acute myeloid leukemia and promyelocytic leukemia could be distinguished from each other and MLL rearranged AML subtypes by 9 and 18 miRNAs, respectively. miR-126, -146a, -181a/b, -100, and miR-125b were identified as highest differentially expressed with marked difference of expression between pediatric and adulthood samples of the same cytogenetic subgroup. We next isolated the miRNA targeting complex from t(8;21) and t(15;17) cell line models and comprehensively identified bound miRNAs and targeted mRNAs by a newly devised immunoprecipitation assay followed by rapid microarray detection. Our findings indicate separate binding preferences for the four human Argonaute proteins. Subsequent bioinformatic analysis revealed a concerted action of different Ago proteins in the regulation of AML-relevant pathways, providing an experimental based database of miRNA-mRNA target interaction in Argonaute proteins. Ago-associated microRNAs: Co-immunoprecipitation in the acute myeloid leukemia cell line models, KASUMI-1 and NB4, of the four human Argonaute complexes using monoclonal antibodies and stringent washing conditions. We performed photo-activated UV cross-linking using 4M-bM-^@M-^Y-thioruidine before cell lysis. Unspecific binding to the bead matrix and to the Fc part of the monoclonal rat antibody were recorded and corrected by empty bead controls and an antibody isotype control. Argonaute-associated miRNAs/mRNAs and unspecific bound miRNAs/mRNAs of the isotype control were identified by microarray hybridization. These experiments were performed in triplicates. Ago-associated mRNAs: Co-immunoprecipitation in the acute myeloid leukemia cell line models, KASUMI-1 and NB4, of the four human Argonaute complexes using monoclonal antibodies and stringent washing conditions. We performed photo-activated UV cross-linking using 4M-bM-^@M-^Y-thioruidine before cell lysis. Unspecific binding to the bead matrix and to the Fc part of the monoclonal rat antibody were recorded and corrected by empty bead controls and an antibody isotype control. Argonaute-associated miRNAs/mRNAs and unspecific bound miRNAs/mRNAs of the isotype control were identified by microarray hybridization. These experiments were performed in triplicates. AML-patient microRNAs: RNA extraction using the TRIzol protocol (Invitrogen), labeling of RNA with Cy3- (universal reference) and Cy5-Dyes (samples) using a truncated and mutated RNA ligase, hybridization of miRNAs over night at 42M-BM-0C using miRXplore microarrays and the a-Hyb Hybridization Station (MACS molecular Miltenyi Biotec)

Dataset Information

Sensitivity and linear dynamic range of miRNA detection

Publications

Absolute quantification of microRNAs by using a universal reference.

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