Comparison of the MagNA pure LC automated system and the RiboPure-Blood RNA manual method for RNA extraction from multiple myeloma bone marrow samples conserved in an RNA stabilizer

Comparison of procedures for RNA-extraction from peripheral blood mononuclear cells

RNA quality and quantity are important factors for ensuring the accuracy of gene expression analysis and other RNA-based downstream applications. Thus far, only a limited number of methodological studies have compared sample storage and RNA extraction procedures for human cells. We compared three commercially available RNA extraction kits, i.e., (NucliSENS) easyMAG, RNeasy (Mini Kit) and RiboPure (RNA Purification Kit–blood). In addition, additional conditions, such as storage medium and storage temperature of human peripheral blood mononuclear cells were evaluated, i.e., 4 °C for RNAlater or -80 °C for QIAzol and for the respective cognate lysis buffers; easyMAG, RNeasy or RiboPure. RNA was extracted from aliquots that had been stored for one day (Run 1) or 83 days (Run 2). After DNase treatment, quantity and quality of RNA were assessed by means of a NanoDrop spectrophotometer, 2100 Bioanalyzer and RT-qPCR for the ACTB reference gene. We observed that high-quality RNA can be obtained using RNeasy and RiboPure, regardless of the storage medium, whereas samples stored in RNAlater resulted in the least amount of RNA extracted. In addition, RiboPure combined with storage of samples in its cognate lysis buffer yielded twice as much RNA as all other procedures. These results were supported by RT-qPCR and by the reproducibility observed for two independent extraction runs.

Retroviral delivery of RNA interference against Marek's disease virus in vivo

The process of RNA interference (RNAi) has been exploited in cultured chicken cells and in chick embryos to assess the effect of specific gene inhibition on phenotypes related to development and disease. We previously demonstrated that avian leukosis virus-based retroviral vectors are capable of delivering effective RNAi against Marek's disease virus (MDV) in cell culture. In this study, similar RNAi vectors are shown to reduce the replication of MDV in live chickens. Retroviral vectors were introduced into d 0 chick embryos, followed by incubation until hatching. Chicks were challenged with 500 pfu of strain 648A MDV at day of hatch, followed by assays for viremia at 14 d postinfection. Birds were monitored for signs of Marek's disease for 8 wk. A stem-loop PCR assay was developed to measure siRNA expression levels in birds. Delivery of RNAi co-targeting the MDV gB glycoprotein gene and ICP4 transcriptional regulatory gene significantly reduced MDV viremia in vivo, although to lesser extents than were observed in cell culture. Concomitant reductions in disease incidence also were observed, and the extent of this effect depended on the potency of the MDV challenge virus inoculum. Successful modification of phenotypic traits in live birds with retroviral RNAi vectors opens up the possibility that such approaches could be used to alter the expression of candidate genes hypothesized to influence a variety of quantitative traits including disease susceptibility.

Modified PAXgene method allows for isolation of high-integrity total RNA from microlitre volumes of mouse whole blood

Analysis of gene expression is often used to evaluate the effects of experimental manipulations in laboratory animals. Blood is a rich source of potential biomarkers, including gene expression information, which may be obtained from whole blood. When compared with the end of a study, when whole blood samples can be easily obtained for gene expression measurements, the limiting volumes of whole blood obtainable from animals during the course of an experiment requires a method for RNA isolation from a minimal volume of whole blood. The PAXgene Blood RNA Extraction System originally designed for isolation of total RNA from 2.5 mL of human whole blood, was modified and successfully used to isolate high-integrity total RNA from as little as 50 microL of mouse whole blood. Fifty microlitres of mouse whole blood yielded an average of 2.3 microg highly intact total RNA, of sufficient quality and quantity allowing for multiple gene expression determinations. The utility of this method was demonstrated by confirming the time- and dose-dependent upregulation of haem oxygenase-1 (Hmox1) mRNA in response to a single injection of cobalt protoporphyrin. The successful isolation of total RNA from small volumes of mouse whole blood can allow for serial sampling on the same animals, thereby reducing the number of animals required for experimentation.

RNA extracted from blood samples with a rapid automated procedure is fit for molecular diagnosis or minimal residual disease monitoring in patients with a variety of malignant blood disorders

Scientific studies in oncology, cancer diagnosis, and monitoring tumor response to therapeutics currently rely on a growing number of clinico-pathological information. These often include molecular analyses. The quality of these analyses depends on both pre-analytical and analytical information and often includes the extraction of DNA and/or RNA from human tissues and cells. The quality and quantity of obtained nucleic acids are of utmost importance. The use of automated techniques presents several advantages over manual techniques, such as reducing technical time and thus cost, and facilitating standardization. The purpose of this study was to validate an automated technique for RNA extraction from cells of patients treated for various malignant blood diseases. A well-established manual technique was compared to an automated technique, in order to extract RNA from blood samples drawn for the molecular diagnosis of a variety of leukemic diseases or monitoring of minimal residual disease. The quality of the RNA was evaluated by real-time quantitative RT-PCR (RQ-PCR) analyses of the Abelson gene transcript. The results show that both techniques produce RNA with comparable quality and quantity, thus suggesting that an automated technique can be substituted for the reference and manual technique used in the daily routine of a molecular pathology laboratory involved in minimal residual disease monitoring. Increased costs of reagents and disposables used for automated techniques can be compensated by a decrease in human resource.

Simultaneous Detection of CDC Category "A" DNA and RNA Bioterrorism Agents by Use of Multiplex PCR & RT-PCR Enzyme Hybridization Assays

Assays to simultaneously detect multiple potential agents of bioterrorism are limited. Two multiplex PCR and RT-PCR enzyme hybridization assays (mPCR-EHA, mRT-PCR-EHA) were developed to simultaneously detect many of the CDC category "A" bioterrorism agents. The "Bio T" DNA assay was developed to detect: Variola major (VM), Bacillus anthracis (BA), Yersinia pestis (YP), Francisella tularensis (FT) and Varicella zoster virus (VZV). The "Bio T" RNA assay (mRT-PCR-EHA) was developed to detect: Ebola virus (Ebola), Lassa fever virus (Lassa), Rift Valley fever (RVF), Hantavirus Sin Nombre species (HSN) and dengue virus (serotypes 1-4). Sensitivity and specificity of the 2 assays were tested by using genomic DNA, recombinant plasmid positive controls, RNA transcripts controls, surrogate (spiked) clinical samples and common respiratory pathogens. The analytical sensitivity (limit of detection (LOD)) of the DNA asssay for genomic DNA was 1x10(0)~1x10(2) copies/mL for BA, FT and YP. The LOD for VZV whole organism was 1x10(-2) TCID(50)/mL. The LOD for recombinant controls ranged from 1x10(2)~1x10(3)copies/mL for BA, FT, YP and VM. The RNA assay demonstrated LOD for RNA transcript controls of 1x10(4)~1x10(6) copies/mL without extraction and 1x10(5)~1x10(6) copies/mL with extraction for Ebola, RVF, Lassa and HSN. The LOD for dengue whole organisms was ~1x10(-4) dilution for dengue 1 and 2, 1x10(4) LD(50)/mL and 1x10(2) LD(50)/mL for dengue 3 and 4. The LOD without extraction for recombinant plasmid DNA controls was ~1x10(3) copies/mL (1.5 input copies/reaction) for Ebola, RVF, Lassa and HSN. No cross-reactivity of primers and probes used in both assays was detected with common respiratory pathogens or between targeted analytes. Clinical sensitivity was estimated using 264 surrogate clinical samples tested with the BioT DNA assay and 549 samples tested with the BioT RNA assay. The clinical specificity is 99.6% and 99.8% for BioT DNA assay and BioT RNA assay, respectively. The surrogate sensitivities of these two assays were 100% (95%CI 83-100) for FT, BA (pX02), YP, VM, VZV, dengue 2,3,4 and 95% (95%CI 75-100) for BA (pX01) and dengue 1 using spiked clinical specimens. The specificity of both BioT multiplex assays on spiked specimens was 100% (95% CI 99-100). Compared to other available assays (culture, serology, PCR, etc.) both the BioT DNA mPCR-EHA and BioT RNA mRT-PCR-EHA are rapid, sensitive and specific assays for detecting many category "A" Bioterrorism agents using a standard thermocycler.