In a recently published study, Anna Krichevsky and colleagues raise the important question of whether results of in vitro extracellular RNA (exRNA) studies, including extracellular vesicle (EV) investigations, are confounded by the presence of RNA in cell culture medium components such as foetal bovine serum (FBS). The answer, according to their data, is a resounding “yes”. Even after lengthy ultracentrifugation to remove bovine EVs from FBS, the majority of exRNA in FBS remained. Although technical factors may affect the degree of depletion, residual EVs and exRNA in FBS could influence the conclusions of in vitro studies: certainly, for secreted RNA, and possibly also for cell-associated RNA. In this commentary, we critically examine some of the literature in this field, including a recent study from some of the authors of this piece, in light of the Wei et al. study and explore how cell culture-derived RNAs may affect what we think we know about EV RNAs. These findings hold particular consequence as the field moves towards a deeper understanding of EV–RNA associations and potential functions.

在最近发表的一项研究中，Anna Krichevsky及其同事提出了一个重要的问题，即体外细胞外RNA（exRNA）研究（包括细胞外囊泡（EV）研究）的结果是否会因细胞培养基成分（如胎儿）中RNA的存在而混淆牛血清（FBS）。根据他们的数据，答案是肯定的“是”。即使经过长时间的超速离心以从FBS中去除牛EV，FBS中的大部分exRNA仍然存在。尽管技术因素可能会影响耗竭程度，但FBS中残留的EV和exRNA可能会影响体外研究的结论：当然，对于分泌的RNA，还可能对与细胞相关的RNA。在这篇评论中，我们将对这一领域的一些文献进行批判性的考察，包括本文的一些作者的最新研究成果，根据Wei等。研究和探索细胞培养来源的RNA如何影响我们对EV RNA的了解。随着该领域对EV-RNA关联和潜在功能的更深入了解，这些发现尤其重要。