Total RNA was extracted by customer following the manufacturer's instructions and checked for a RIN number to inspect RNA integrity by an Agilent Bioanalyzer 2100 (Agilent technologies, Santa Clara, CA, US).Qualified total RNA was further purified by RNAClean XP Kit (Cat A63987, Beckman Coulter,Inc.Kraemer Boulevard Brea, CA,USA)and RNase-Free DNase Set (Cat#79254, QIAGEN, GmBH, Germany). Following Illumina's (San Diego, California, USA) experimental protocol, purified total RNA underwent mRNA isolation, fragmentation, first-strand cDNA synthesis, second-strand cDNA synthesis, end repair, 3'-end A-addition, adapter ligation, and enrichment to complete sequencing library preparation.