Comparability of the small RNA secretome across human biofluids concomitantly collected from healthy adults. Comparability of the small RNA secretome across human biofluids concomitantly collected from healthy adults

Small extracellular vesicles (sEV) are nano-sized (40-150 nm), membrane-encapsulated vesicles that are released by malignant or pathologic and non-pathologic cells into the extracellular space and function as intercellular signaling vectors through the horizontal transfer of biologic molecules, including microRNA (miRNA) and other small non-coding RNA (ncRNA), that can alter the phenotype of recipient cells. sEV are present in essentially all extracellular biofluids, including serum, urine and saliva, and offer a new avenue for discovery and development of novel biomarkers of various disease states and exposures. The objective of this study was to determine the similarities and differences between sEV ncRNA derived from saliva, serum and urine, as well as cell-free ncRNA from serum. Saliva, urine and serum were concomitantly collected from 4 healthy donors, and sEV were isolated from each respective biofluid, along with cfRNA from serum. sEVs were isolated from the respective biofluids via differential ultracentrifugation. Small RNA-sequencing was performed on each sample, and cluster analysis was performed based on ncRNA profiles. While some similarities existed in terms of sEV ncRNA cargo across biofluids, there are also notable differences in ncRNA class and ncRNA secretion, with each sEVs in each biofluid bearing a unique ncRNA profile. We conclude that sEV ncRNA cargo varies according to biofluid, so thus should be carefully selected and interpreted when designing translational or epidemiological studies. Overall design: Saliva, urine and serum were concomitantly collected from 4 healthy donors, and sEV were isolated from each respective biofluid, along with cfRNA from serum. sEVs were isolated from the respective biofluids via differential ultracentrifugation. Small RNA-sequencing was performed on each sample, and cluster analysis was performed based on ncRNA profiles.

细胞外小囊泡（Small extracellular vesicles, sEV）是一类粒径介于40~150 nm的膜包裹囊泡，可由恶性细胞、病理性细胞及正常细胞释放至细胞外空间，通过水平转运生物分子（包括微小RNA（microRNA, miRNA）及其他小型非编码RNA（non-coding RNA, ncRNA））发挥细胞间信号传递载体的功能，能够改变受体细胞的表型。sEV几乎存在于所有细胞外生物体液中，涵盖血清、尿液与唾液，为多种疾病状态及暴露状态的新型生物标志物的发现与开发提供了全新途径。本研究旨在明确唾液、血清与尿液来源的sEV ncRNA，以及血清无细胞ncRNA（cell-free ncRNA, cfRNA）之间的异同点。研究人员从4名健康供者体内同步采集唾液、尿液与血清样本，从各生物体液中分离sEV，并同步提取血清中的cfRNA。采用差速超速离心法（differential ultracentrifugation）从各生物体液中分离sEV，对所有样本开展小RNA测序（small RNA-sequencing），并基于ncRNA表达谱进行聚类分析（cluster analysis）。尽管不同生物体液来源的sEV ncRNA载荷存在部分共性，但在ncRNA类别与分泌模式上也存在显著差异，且各生物体液中的sEV均具有独特的ncRNA表达谱。本研究证实，sEV的ncRNA载荷因生物体液类型而异，因此在设计转化医学或流行病学研究时，需对其进行审慎选择与解读。整体实验设计：从4名健康供者体内同步采集唾液、尿液与血清样本，从各生物体液中分离sEV，并同步提取血清中的cfRNA。采用差速超速离心法从各生物体液中分离sEV，对所有样本开展小RNA测序，并基于ncRNA表达谱进行聚类分析。