bEnd.3 was collected from the PSS group, the HSS group and the VSS group respectively. Total RNA was extracted from the samples using TRIzol reagent (Invitrogen, USA). The mixed RNA samples from the three groups were sent to Shanghai Lifegenes Technology Co., Ltd.（Shanghai Lifegenes Technology, China） for transcriptome sequencing analysis. A total amount of 1.5 µg RNA per sample was used as input material for the RNA sample preparations. Sequencing libraries were generated using NEBNext Ultra RNA Library Prep Kit for Illumina (NEB, USA) following manufacturer's recommendations and index codes were added to attribute sequences to each sample.