Comparison of the miRNome and piRNome of Bovine Blood and Plasma - Insights by Small RNA Sequencing

Objectives: The small RNAs of bovine plasma and whole blood were analysed using Next-Generation Sequencing to quantify, profile and compare the miRNA and piRNA signatures in both bio fluids. Results: Evaluating readcount data resulted in a proportion of 5.0 ± 2.9 % of miRNAs in plasma while 38.2 ± 3.4 % were identified in whole blood. Regarding piRNAs, the percentages in both matrices were nearly the same: 1.4 ± 0.8 % of piRNAs in plasma and 1.9 ± 0.8 % in whole blood. Investigation of the ten most abundant miRNAs and piRNAs in both bio fluids revealed that two miRNAs and seven piRNAs were identical. Comparing the readcount values of these matching pairs highlighted that miRNA and piRNA levels in blood exceeded the abundance of their corresponding miRNAs and piRNAs in plasma, except liver-specific miR-122 and three piRNAs. Conclusions: The data strengthened evidence that the circulating small RNA signature in plasma is not only influenced by blood cells and certain small RNAs could originate from other sources than cellular blood components.