Variety of RNAs in Peripheral Blood Cells, Plasma, and Plasma Fractions.

Anna V Savelyeva,Dmitry N Bariakin,Vladimir A Richter,Dmitry V Semenov,Elena V Kuligina,Vadim V Kozlov,Elena I Ryabchikova

doi:10.1155/2017/7404912

Abstract

Human peripheral blood contains RNA in cells and in extracellular membrane vesicles, microvesicles and exosomes, as well as in cell-free ribonucleoproteins. Circulating mRNAs and noncoding RNAs, being internalized, possess the ability to modulate vital processes in recipient cells. In this study, with SOLiD sequencing technology, we performed identification, classification, and quantification of RNAs from blood fractions: cells, plasma, plasma vesicles pelleted at 16,000g and 160,000g, and vesicle-depleted plasma supernatant of healthy donors and non-small cell lung cancer (NSCLC) patients. It was determined that 16,000g blood plasma vesicles were enriched with cell-free mitochondria and with a set of mitochondrial RNAs. The variable RNA set of blood plasma 160,000g pellets reflected the prominent contribution of U1, U5, and U6 small nuclear RNAs' fragments and at the same time was characterized by a remarkable depletion of small nucleolar RNAs. Besides microRNAs, the variety of fragments of mRNAs and snoRNAs dominated in the set of circulating RNAs differentially expressed in blood fractions of NSCLC patients. Taken together, our data emphasize that not only extracellular microRNAs but also circulating fragments of messenger and small nuclear/nucleolar RNAs represent prominent classes of circulating regulatory ncRNAs as well as promising circulating biomarkers for the development of disease diagnostic approaches.

Highlights

IntroductionBlood contains RNA within nucleated and enucleated cells as well as cell-free RNA, circulating in membrane vesicles (apoptotic bodies, microvesicles, and exosomes) and in cell-free ribonucleoproteins
Blood contains RNA within nucleated and enucleated cells as well as cell-free RNA, circulating in membrane vesicles and in cell-free ribonucleoproteins
We analysed the RNA profiles of human blood fractions obtained with sequential centrifugation of whole blood and blood plasma

Summary

Introduction

Blood contains RNA within nucleated and enucleated cells as well as cell-free RNA, circulating in membrane vesicles (apoptotic bodies, microvesicles, and exosomes) and in cell-free ribonucleoproteins. Specific changes in the RNA profile of whole peripheral blood or in the RNA profile of blood fractions such as plasma/serum might reflect physiological and pathological processes occurring in different cells and tissues of the body [1, 2]. Recent studies have concentrated on extracellular RNAs circulating in membrane vesicles such as microvesicles, exosomes, and apoptotic bodies. Microvesicles of 50–2000 nm diameter are budded from the outer plasma membrane of progenitor cells, while exosomes have a smaller diameter of ∼30–150 nm and are generated during the maturation of multivesicular bodies (MVB) by multiple invaginations of the late endosome membrane and intraluminal vesicle budding followed by exocytosis of MVB content [1, 6]. Apoptotic bodies have a larger diameter (50–5000 nm) and are released by cells undergoing apoptosis and thereby can contain cell organelles [7, 8]

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