High-throughput single-cell transcriptomes of the brain of the nudibranch Berghia stephanieae

Previously, transcriptomics data for mollusc has been obtained by whole-brain bulk RNA-seq and low-throughput scRNA-seq. We want to construct the first molluscan high-throughput single-neuron transcriptomes for Berghia stephanieae. Around 129,000 cells were collected from 20 brains and the libraries were constructed using the 10X Genomics' Chromium platform. The brains were separated into two samples: the main brain (i.e., the cerebropleural, pedal, buccal ganglion) and the rhinophore ganglion sample. After library preparation, around 1,000 cells were receovered and sequenced. After data analysis, the cells formed eight clusters with marker genes for each cluster identified. Various cell populations that express a wide range of both small-molecule neurotransmitters and neuropeptides such as serotonergic, small cardioactive peptide (SCP), APGWamide, and FMRFamide cells were also identified in the dataset. Interestingly, cells from the rhinophore ganglion of Berghia exhibit great cell heterogeneity, with cells splitting into two general categories and four distinct clusters. The project produced a single-cell dissociation protocol that can be adapted for use in other nudibranch molluscs and a custom data analysis pipeline for data of this nature. Single-cell sequencing of whole brain tissue of Berghia stephanieae using 10X Genomics' Chromium Single Cell Gene Expression v3. Two samples (i.e. the main brain and the rhinophore ganglion sample) were fixed in methanol

此前，软体动物的转录组学数据多通过全脑批量RNA测序（bulk RNA-seq）与低通量单细胞RNA测序（scRNA-seq）获取。本研究旨在构建首个针对史氏蓑海牛（Berghia stephanieae）的软体动物高通量单神经元转录组数据集。研究团队从20个脑部样本中收集了约129,000个细胞，并采用10X Genomics的Chromium平台构建测序文库。脑部样本被分为两组：主脑样本（即脑侧、足与口神经节复合体）与嗅角神经节样本。文库构建完成后，共回收约1000个细胞进行测序。数据分析阶段，研究人员将细胞划分为8个细胞簇，并鉴定出每个细胞簇的标志性基因。本数据集同时鉴定出了表达多种小分子神经递质与神经肽的各类细胞群，包括5-羟色胺能神经元、小心血管活性肽（SCP）能神经元、APGWamide能神经元以及FMRFamide能神经元。值得注意的是，史氏蓑海牛嗅角神经节的细胞展现出极高的细胞异质性，可被划分为两大类群与4个独立的细胞簇。本项目开发了一套可适配其他裸鳃类软体动物的单细胞解离方案，以及针对此类数据的定制化数据分析流程。本研究采用10X Genomics Chromium单细胞基因表达V3试剂盒，对史氏蓑海牛的全脑组织进行了单细胞测序。两组样本（即主脑样本与嗅角神经节样本）均采用甲醇进行固定。