Reproducibility of Quantitative RT-PCR Array in miRNA Expression Profiling and Comparison with Microarray Analysis
ABSTRACT: 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. Replicate preparations (n =4) using different aliquots of a single C2C12 RNA sample (500 ng) were used to determine the reproducibility of the reverse transcription process as well as the results of the same reverse transcription products performed on different days. TaqMan microRNA Array A was used for this purpose. To assess the reliability of pre-amplification, miRNA expression profiles obtained with and without pre-amplification using MiRNA TaqMan Array B were performed. Independent miRNA expression profiling studies using uParaflo microfluidic biochips were performed by an independent company to determine the relationship between results obtained with qPCR-array and microarrays. Aliquots of the same C2C12 RNA were used in both the qPCR-array (500 ng) and microarrays (8 µg).
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. Overall design: Replicate preparations (n =4) using different aliquots of a single C2C12 RNA sample (500 ng) were used to determine the reproducibility of the reverse transcription process as well as the results of the same reverse transcription products performed on different days. TaqMan microRNA Array A was used for this purpose. To assess the reliability of pre-amplification, miRNA expression profiles obtained with and without pre-amplification using MiRNA TaqMan Array B were performed. Independent miRNA expression profiling studies using uParaflo microfluidic biochips were performed by an independent company to determine the relationship between results obtained with qPCR-array and microarrays. Aliquots of the same C2C12 RNA were used in both the qPCR-array (500 ng) and microarrays (8 µg).
Project description:Eosinophlic esophagitis (EoE) is increasely recognized as an antigen-drived disorder. The goal of this study is to reveal the miRNA expression changes in EoE before and after a successful glucocorticoid steroid treatment. Total RNA was extracted from the esophageal epithelial layers of 5 paired paraffin-embedded biopsies before and after treatment with glucocorticosteroids using RecoverAll Total Nucleic Acid Extraction Kit for FFPE tissues (Ambion, Austin, TX). Five nanograms of total RNA was reverse-transcribed using the Taqman MicroRNA Reverse Transcription Kit and the Megaplex RT primer Human Pool A (Applied Biosystems). The reverse-transcribed cDNA was then pre-amplified in 12 cycles of PCR using Taqman PreAmp Master Mix and the Megaplex PreAmp primers, Human Pool A (Applied Biosystems). The cDNA’s were then diluted and loaded on to a Taqman Human miRNA Array card A (Platform GPL9731 ; Applied Biosystems), which contains probes for 377 distinct miRNAs. The Array cards were run on an ABI HT7900 qPCR instrument. Ct values were obtained for all miRNAs represented on the cards and fold changes in expression were calculated using the delta delta Ct (ddCt) method.
Project description:We addressed the potential for global regulation of miRNA biogenesis by BDNF using miRNA arrays that selectively measure mature miRNA, as opposed to pre-miRNA. Hippocampal neurons were treated with BDNF for 30 min in the presence of Actinomycin-D to assess changes due to processing of existing pre-miRNAs rather than new pre-miRNA production. We used Applied Biosystems 7900HT Fast Real-Time PCR system using Taqman Rodent MicroRNA Array A. Data is from three paired BDNF and Mock experiments (1,2,3). Each array (TaqMan) contained 375 rodent miRNA targets of which 195 were detectable in hippocampus in three independent paired experiments.
Project description:Dysregulated miRNA in human colorectal cancer (CRC) were identified through comparison between 4 CRC tumors and their adjacent normal tissues by miRNA array. Histologically-confirmed CRC were included in this study. CRC tissues and paired adjacent normal tissues were obtained from the resected surgical specimens. The adjacent normal tissue is composed of normal colonic mucosa located at approximately 10 cm away from the cancer tissue. miRNA profiling of 754 human miRNAs was performed using TaqMan Human MiRNA Array Set v3.0. Quantitative real-time polymerase chain reaction (Q-PCR) was performed using Applied Biosystems 7900HT Real-Time PCR System (Applied Biosystems). Results were analyzed by the SDS RQ Manager 1.2 software (Applied Biosystems). 4 CRC tissues and 4 adjacent normal tissues were subjucted to qPCR based miRNA expression profiling. Equal amount of total RNA were used for analysis.
Project description:Recent studies have reported both mRNA and microRNA (miRNA) in saliva, but little information has been documented on the quality and yield of RNA collected. Therefore, the aim of the present study was to develop an improved RNA isolation method from saliva and to identify major miRNA species in human whole saliva. RNA samples were isolated from normal human saliva using a combined protocol based on the Oragene RNA collection kit and the mirVana miRNA isolation kit in tandem. RNA samples were analyzed for quality and subjected to miRNA array analysis. Twelve representing 6 males and 6 females, were selected for miRNA profiling using the TaqMan® Low Density Array Card (TLDA) Human miRNA Panel v2.0 (Applied Biosystems). The analysis of expression of the >700 miRNAs was performed by the DNA Core at the Interdisciplinary Center for Biotechnology Research Center at the University of Florida, according to the manufacturer’s protocol except the pre-amplification step was omitted. The NormFinder algorithm was used to identify the optimal normalization of miRNA among the 25 most abundantly expressed miRNAs detected.
Project description:Jeko-1 cells were culture with or without PRC2 inhibitor 3-deazaneplanocin A (DZNep)(1uM) for 72hrs. We used TaqMan® Human MicroRNA Array to quantitate miRNA expression profile regulated by PRC2. qPCR miRNA expression profiling.
Project description:MicroRNAs (miRNAs) regulate activity of protein-coding genes including those involved in hematopoietic cancers. The goal of the current study was to explore which miRNAs are unique for seven different subtypes of pediatric acute lymphoblastic leukemia (ALL). Therefore, the expression levels of 397 miRNAs (including novel miRNAs) were measured by quantitative RT-PCR in 81 pediatric leukemia cases and 17 normal hematopoietic control cases. Except for BCR-ABL-positive and B-other ALL, all major subtypes i.e. T-ALL, MLL-rearranged, TEL-AML1-positive, E2A-PBX1-positive and hyperdiploid ALL have unique miRNA-signatures that differ from each other and from those in healthy hematopoietic cells. Strikingly, the miRNA signature between TEL-AML1-positive and hyperdiploid cases partly overlapped, which suggests a common underlying biology. Moreover, aberrant downregulation of let-7b (~70-fold) in MLL-rearranged ALL was linked to upregulation of oncoprotein c-Myc (P<0.0001). Besides genetic aberrations, in vitro drug resistance predicts clinical outcome. Resistance to vincristine and daunorubicin was characterized by ~20-fold upregulation of miR-125b, miR-99a and miR-100 (P≤0.002). No discriminative miRNAs were found for prednisolone and only one miRNA was linked to L-asparaginase resistance. Finally we show that the expression levels of 14 miRNAs were --independently of subtype-- associated with clinical outcome in pediatric ALL. We conclude that genetic subtypes and drug resistant leukemic cells display characteristic miRNA signatures in pediatric ALL. Functional studies of discriminative and prognostic important miRNAs may provide new insights into the biology of disease. Experiment type: stem-loop real-time (RT) quantitative PCR (RT-qPCR) Bone marrow and peripheral blood samples were collected from children at newly diagnosis of acute lymphoblastic leukemia (ALL). CD34+ -cells were sorted from G-CSF-stimulated blood cell samples of children with a brain tumor or Wilm’s tumor. Thymocytes were isolated from thymic lobes that were resected from children during surgery for congenital heart disease. RNA from the cell samples was extracted using TRIzol reagents (firma). Only RNA with an RNA Integrity Number (RIN) of ≥ 7.5 as measured by the 2100 Bioanalyzer (Agilent, Amstelveen, the Netherlands) was used as input for the RT-qPCR reactions. All miRNAs were validated with the stem-loop real-time (RT) quantitative PCR (RT-qPCR) technique by using either TaqMan MicroRNA Array MicroRNA arrays (v 1.0, Early Access) or Custom TaqMan MicroRNA Array arrays (Applied Biosystems, Foster City, USA). Values represent ∆Ct in each individual patient for whom the specific subtype, identification number and cellular drug-resistance is shown on top of each column. Drug-resistance was based on median LC50 values (concentration of a drug lethal to 50% of the leukemic cells) that have reported prognostic impact in children with newly diagnosed ALL. Median LC50 values were used to assign patients as sensitive (≤ median LC50) or resistant (> median LC50) to the drug in question. The ∆Ct value was calculated according to the following equation: Ct value of the specific miRNA minus the Ct value of the internal reference. In case of the TaqMan MicroRNA Array MicroRNA arrays the mean Ct values for snoR-13 and snoR-14 were used as reference whereas in case of the Custom TaqMan MicroRNA Array arrays snoR-1 was used. MiRNAs validated by the TaqMan MicroRNA Array MicroRNA arrays are listed together with the part numbers of the corresponding (stem-loop) primers as available by Applied Biosystems, Foster City, USA. Primers for the remaining miRNAs were custom designed by Applied Biosystems. Abbreviations: MLL: MLL-rearranged precursor B-ALL, B-other: precursor B-ALL negative for MLL-rearrangements, TEL-AML1, BCR-ABL, E2A-PBX and hyperdiploidy (> 50 chromosomes). CD34+: normal CD34+-sorted blood progenitor cells, nBM: normal bone marrow.
Project description:The study sought to determine the global miRNA profile of ventricles during early and end-stage hypertrophic cardiomyopathy in a severe double mutant mouse model of the disease. MicroRNA expression profiles of ventricles of transgenic mice with a mutation in both the myosin heavy chain gene (MYH7 Arg403Gln) and cardiac troponin I gene (TNNI3 Ser203Gln) and of non-transgenic mice were determined using Rodent TaqMan Low Density miRNA Arrays A v2.0 (TLDA, Life Technologies). MicroRNA profiles were measured at 10 days of age and 16 days of age, in 3 biological replicates. qRT-PCR analysis of microRNAs of ventricles of three transgenic mice and three non-transgenic mice age 10 days, and three transgenic mice and three non-transgenic mice age 16 days. 450 ng RNA was reverse transcribed, without pre-amplification, using TaqMan MicroRNA Reverse Transcription Kit and Megaplex RT Primers rodent pool A (Life Technologies). Complementary DNA (cDNA) was amplified using a TaqMan rodent microRNA A Array v2.0 (Life Technologies) with TaqMan Universal PCR Master Mix on an ABI 7900HT Sequence Detection System.
Project description:Lung cancer is the leading cause of cancer death worldwide. Low-dose computed tomography screening (LDCT) was recently shown to anticipate the time of diagnosis, thus reducing lung cancer mortality. We identifed a serum microRNA signature (the miR-Test) that could identify the optimal target population for LDCT screening. Here, we performed a large-scale validation study of the miR-Test in high-risk individuals enrolled in the Continuous Observation of Smoking Subjects (COSMOS) lung cancer screening program. RT-qPCR of circulating microRNA purified from serum samples. Trizol-LS and miRNEASY Mini kit (Qiagen) were used for miRNA purification. Custom TaqMan® Low Density Array microRNA Custom Panel (Life Technologies) was used to screen serum circulating microRNA.
Project description:DICER is a central regulator of microRNA maturation. However little is known about mechanisms regulating its expression in development or disease. While profiling miRNA expression in differentiating melanocytes, two populations were observed: some upregulated at the pre-miRNA stage, and others upregulated as “mature” miRNAs (with stable pre-miRNA levels). Conversion of pre-miRNAs to fully processed miRNAs appeared to be dependent upon stimulation of DICER expression—an event found to occur via direct transcriptional targeting of DICER by the melanocyte master transcriptional regulator MITF. MITF binds and activates a conserved regulatory element upstream of DICER’s transcriptional start site upon melanocyte differentiation. Targeted knockout of DICER is lethal to melanocytes, at least partly via DICER-dependent processing of the pre-miRNA-17~92 cluster thus targeting BIM, a known pro-apoptotic regulator of melanocyte survival. These observations highlight a central mechanism underlying miRNA regulation which could exist for other cell types during development. Primary melanocytes were obtained from 7 independent donors. Mature-miRNA levels were detected using Applied Biosystem's TaqMan PCR assay.