Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Absolute quantification of miRNAs

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. Total liver RNA was mixed with 2.5 fmol of each of 18 RNA oligonucleotides reverse complement to miRControl 3 probes and subsequently fluorescently labelled by 3â ligation. Total RNA mix was hybridized in a dual colour approach to microarrays versus a second labelled synthetic miRNA pool (n = 6). The synthetic miRNA pool consisted of 2.5 fmol of each of 891 non redundant miRNAs sequences and miRControl 3 sequences. The array data was normalized by calculating the median of the miRControl 3 present in the liver and UR sample. The miRNA amount was calculated with respect to the corresponding miRNA in the UR.

ORGANISM(S): Mus musculus

SUBMITTER: Ute Bissels

PROVIDER: E-GEOD-15835 | 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. 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. 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. 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:The subpopulations of mesenchymal stem cells isolated from breast adipose tissue which display migrated towards conditioned media from MDA-MB231 cell line were expanded for miRNA analysis. The tumor microenvironment (TM) is known to promote tumor growth and progression. Ubiquitously distributed tissue resident stem cells (MSCs) elicit regenerative properties. In addition, they are capable of homing to sites of inflammation, injury, and tumor. Considering the tumor tropic property of MSCs, the interaction between the breast cancer (BC) microenvironment and breast resident adipose tissue derived MSCs (ASCs) merits further investigations. Initial data indicate that a subset of ASCs derived from breast adipose tissue (B-ASCs) display a high affinity towards the conditioned media (CM) from two breast cancer cell lines, MDA-MB231 (MDA-CM) and MCF7 (MCF-CM). Profiling secreted cytokines of these CMs identified significant expression of angiogenin, GM-CSF, and IL-6. While the expression of GRO-M-NM-1, MCP-1, RANTES, and IL-1M-NM-1 is more pronounced in MDA-CM, MCF-CM contains higher amounts of IGFBP2, TRAIL, and ErbB3. Gene expression profiling suggests that despite the distinct differences, both migratory subset of B-ASCs towards MDA-CM and MCF-CM display perturbed expression of genes like KISS1, TNSF1, IL18 and MMP2, which could be associated with a defensive role of B-ASCs. In addition, the BC microenvironment alters microRNA (miRNA) expressions in B-ASCs. in this study the migratory cells were evaluated for miRNA expression versus non-migratory counterparts. as controls unexposed parental cell lines (2) were used on the same hybridization chip in which one labeled Hy3 and other labeled Hy5. The ratio of the control parental cells was used as base nanalysis of miRNA expression in MSCs. we also include another control in this study, the migratory subpopulations of MSCs which display migratory potentials against protein gradient (M5) were analyzed for miRNA expression versus non-migratory counterparts (NM-5). using this control facilitate identification of those miRNA responsive to tumor CM. the data analysis confirm that altered gene and miRNA profiles resulted from exposure of MCF-CM and MDA-CM on B-ASCs are similar to those observed in B-ASCs isolated from breast adipose tissue of BC patients. Analysis the signaling between the B-ASCs and TM may help in understanding the possible role of B-ASCs in stasis, progression, or regression of the BC. The microRNA expression of migratory subpopulations were compared to parental populations of MSCs.

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)

Dataset Information

Absolute quantification of miRNAs

Publications

Absolute quantification of microRNAs by using a universal reference.

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