title: miRNA-seq of homo sapiens:exosomes from cell medium
design: Exosomal miRNA extraction and miRNA microarray profiling was carried out by the Beijing Genomics Institute (BGI). Briefly, total RNA was extracted from the exosomes using Trizol according to the manual instructions. Library was prepared with 1 g total RNA for each sample. Total RNA was purified and the 1830 nt small RNAs were excised, recovered and followed with adapter-ligation with unique barcodes. The adapter-ligated small RNAs were subsequently transcribed into cDNA and then several rounds of PCR amplification.The PCR products were selected and purified. The library was quality and quantitated in two methods: check the distribution of the fragments size using the Agilent 2100 bioanalyzer, and quantify the library using real-time quantitative PCR (QPCR) (TaqMan Probe). The final ligation PCR products were sequenced using the BGISEQ-500 platform (BGI-Shenzhen, China).