MicroRNA Expression Profiling in Biofluids

Serum, plasma and other bodily fluids contain microRNA that can serve as biomarkers in many disease states including cancer ( Chen, X et al., 2008 , Mitchell, P.S. et al., 2008 ). Despite the extremely low amount of RNA found in cell-free serum samples, ORB has developed robust protocols for microarray-based profiling of microRNA in serum using our custom ORB version 4.0 mammalian microRNA arrays. 115 human microRNAs were detected in serum from normal volunteers in our preliminary experiments. For a comparative analysis of the number of microRNAs detected from serum vs. human universal tissue pool see Figure 1 below.

Pathway analysis using WEB-based GEne SeT AnaLysis Toolkit (WebGestalt) of the genes targeted by the microRNAs uniquely expressed in serum showed interesting gene networks (Figure 2) that are potentially affected by the serum microRNA. The list of the top 5 significant KEGG and Biocarta pathways identified in our preliminary studies in serum is shown in Table 1 (A & B) below. ORB offers this analysis service to all its interested microRNA profiling customers.

ORB requires at least 4 ml of serum or other biofluid per sample to obtain the required amount of RNA for microRNA profiling. ORB's process begins with removal of cells by high-speed centrifugation followed by filtration through 0.2-micron filter to ensure that the biofluid is cell free. To ensure the quality of our isolation and labeling procedures, we spike a set of synthetic microRNAs in to each sample. We also perform a quality control test using ABI Taqman real time PCR on the samples to detect the presence of the synthetic spiked RNAs and an endogenous ubiquitous microRNA. The samples that pass the QC test are then labeled using the sensitive Genisphere - Flash tag labeling system and hybridized to ORB version 4.0 arrays.

Our standard data analysis package includes quality control report, log-transformation, normalization, and spot averaging. Data presented in Excel workbook includes detection/ non-detection calls, ANOVA, hierarchical clustering, and principal component analysis (where applicable). MicroRNA pathway analysis and/or correlation of microRNA data to gene expression data is available to interested customers.

Please click here to inquire about pricing for Biofluid MicroRNA Profiling.