Serum-free media supplements carry miRNAs that co-purify with extracellular vesicles (EVs)

With the goal to identify miRNAs and other small RNAs involved in EV-mediated oligodendrocyte-neuron communication, we performed deep sequencing (RNA-seq) of small RNAs derived from EVs isolated from culture supernatants of primary mouse oligodendrocytes by differential centrifugation. Oligodendrocytes were cultured and EVs harvested under serum-free conditions in presence of B27 supplement. We found that RNA isolated from EVs harvested from cells under serum-replacement conditions contains miRNA contaminants carried into the sample by defined media components. Overall design: Small RNA expression profiling of extracellular vesicles (EVs) derived from mouse oligodendrocytes