GSM7733700: CSF, control 1; Homo sapiens; ncRNA-Seq
mirVanaTM PARISTM RNA and native protein purification kit (AM1556, Invitrogen, Waltham, MA) was used to extract total RNAs from 300 µl CSF or 250 µl serum samples, according to the manufacturer's protocol. 5 μl of 5 nM artificial microRNA (cel-miR-39) was spiked after denaturing endogenous ribonucleases to control extraction efficiency. At the elution step, samples were incubated on the column for 5 min at 65 ℃, and RNAs were eluted with 45 μl nuclease-free water. TRIzol reagents (Thermo Fisher Scientific, Hercules, CA) were used to extract RNAs from the hippocampus. RNAs were treated with T4 PNK (New England Biolabs, Ipswich, MA, US) to make the 3'-end of tRFs homogenously with 3'-OH before the ligation with sequencing barcodes, as the ligation of the 3′-end of sncRNAs with sequencing barcodes requires the presence of 3′-OH and not all sncRNAs have 3-OH ends. The treated RNA was purified and concentrated using Zymo RNA Clean and Concentrator kit (D4060, Thomas Scientific, Swedesboro, NJ). Small RNA libraries were then prepared with NEB Next Multiplex Small RNA Library Prep Set for Illumina (Ipswich, MA, US).