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MicroRNAs (miRNAs) are short noncoding RNA molecules that control the expression of mRNAs associated with various biological processes. Therefore, deregulated miRNAs play important roles in the pathogenesis of diseases. Numerous studies are aimed at discovering biomarkers of diseases or determining miRNA functions by monitoring circulating miRNAs in various biological sources such as plasma and urine. However, the analysis of miRNA in such fluids presents problems related to accuracy and reproducibility because of their low levels in biological fluids. Therefore, better extraction kits and more sensitive detection systems have been developed for improved and reproducible analysis of circulating miRNAs. However, new extraction methods are also needed to improve the yield of miRNAs for their reliable analysis from biological fluids. The combination of yeast transfer RNA (tRNA) and glycogen as carrier molecules and incubation durations were optimized to maximize extraction efficiency. The extraction recovery using a combination of yeast tRNA and glycogen was approximately threefold more than that by using glycogen or yeast tRNA alone. In addition, reproducible and accurate analysis of miRNAs can be carried out after extraction using a combination of yeast tRNA and glycogen without an impact on plasma components. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are short RNA molecules that control the expression of mRNAs associated with various biological processes. Therefore, deregulated miRNAs play an important role in the pathogenesis of diseases. Numerous studies aimed at developing novel miRNA-based drugs or determining miRNA functions have been conducted by inhibiting miRNAs using anti-miRNA oligonucleotides (AMOs), which inhibit the function by hybridizing with miRNA. To increase the binding affinity and specificity to target miRNA, AMOs with various chemical modifications have been developed. Evaluating the potency of these various types of AMOs is an essential step in their development. In this study, we developed a capillary electrophoresis with laser-induced fluorescence (CE-LIF) method to evaluate the potency of AMOs by measuring changes in miRNA levels with fluorescence-labeled ssDNA probes using AMO-miR-23a, which inhibits miR-23a related to lung cancer. In order to eliminate interference by excess AMOs during hybridization of the ssDNA probe with the miR-23a, the concentration of the ssDNA probe was optimized. This newly developed method was used to compare the potency of two different modified AMOs. The data were supported by the results of a luciferase assay. This study demonstrated that CE-LIF analysis could be used to accurately evaluate AMO potency in biological samples. [ABSTRACT FROM AUTHOR]

The determination of microRNA (miRNA) levels in biomaterials has become important for understanding their biological functions and for the diagnosis of various diseases. An effective extraction method is needed for maximizing the recovery of miRNAs from cells, while minimizing RNA degradation during the extraction because miRNAs present only approximately 0.01 % of total RNA. In this study, we used Triton X-100 (TX-100) to improve the extraction efficiency of miRNAs with TRIzol® reagent, which is a commonly used commercial microRNA isolation kit. The concentration of TX-100 and the incubation time after the addition of TX-100 were optimized to maximize the extraction efficiency. The extraction recovery by a combination of TX-100 and TRIzol® reagent was approximately 1.9-fold greater than that by the TRIzol® reagent alone. We have established a very effective extraction method for the extraction of low-abundance miRNAs in biological samples for the determination of miRNA levels in biomaterials. [ABSTRACT FROM AUTHOR]