ABSTRACT
Dietary microRNAs (miRNAs), notably those found in milk, are currently being investigated for their potential to elicit biological effects via canonical binding to human messenger RNA targets once ingested. Besides milk, beef and other bovine tissue-derived ingredients could also be a relevant source of potentially bioactive dietary miRNAs. In this study, we characterized the human homologous miRNA profiles in food-grade, bovine-sourced sirloin, heart and adrenal tissue (raw, cooked, and pasteurized, freeze-dried extracts) via deep-sequencing and quantitative reverse transcription PCR (RT-qPCR). A total of 198 human homologous miRNAs were detected at 10 or more normalized reads in all replicates (n = 3) of at least one preparation method. Tissue origin rather than preparation method was the major differentiating factor of miRNA profiles, and adrenal-based miRNA profiles were the most distinct. The ten most prevalent miRNAs in each tissue represented 71-93% of the total normalized counts for all annotated miRNAs. In cooked sirloin, the most abundant miRNAs were miR-10b-5p, (48.8% of total annotated miRNA reads) along with the muscle-specific miR-1 (24.1%) and miR-206 (4.8%). In dried heart extracts, miR-1 (17.0%), miR-100-5p (16.1%) and miR-99a-5p (11.0%) gave the highest normalized read counts. In dried adrenal extracts, miR-10b-5p (71.2%) was the most prominent followed by miR-143-3p (7.1%) and 146b-5p (3.7%). Sequencing results for five detected and two undetected miRNAs were successfully validated by RT-qPCR. We conclude that edible, bovine tissues contain unique profiles of human homologous dietary miRNAs that survive heat-based preparation methods.
