MicroRNA profiling. RNA was converted to cDNA using universal
reverse transcription (RT) primers (First Strand cDNA; Qiagen)
and standard reverse transcription procedures. An eight-channel
liquid handler (Microlab Starlet; Hamilton Robotics NV, USA) was
used to increase throughput and reduce error. To analyze miRNA
expression, we used miFinder RT2 miRNA polymerase chain reaction
(PCR) arrays (SA Bioscience Quiagen Group, Hilden Germany) to measure
the expression of 88 miRNA sequences (Table S1, Supplemental
Materials). Real-time PCR was performed using RT2 qPCR MasterMix
(Qiagen). Because there is no known control miRNA in MVs, small
nucleolar (sno) RNAs were used as controls. The control primers used
were SNORD48, SNORD47, SNORD44U38B and RNU6-2.