Functional signaling and gene regulatory networks between the oocyte and the surrounding cumulus cells

The maturation of an oocyte, the female gamete, during folliculogenesis is highly dependent on the molecular interaction with the somatic cells. Here we generated transcriptome data of single oocytes and the surrounding cumulus cells from antral follicles, and developed an analytical framework to unveil their inter-cellular communication. We identified hundreds of ligand-receptors pairs that can transduce paracrine signaling between oocyte and cumulus. Several of the ligand-coding genes expressed in oocytes and cumulus cells are also functionally associated with regulation of transcription. Ligand-coding genes expressed in oocytes or cumulus showed distinct enrichment for biological functions that are likely associated with a coordinated formation of the transzonal projections from the cumulus that reach the oocyte's membrane. Finally, there were thousands of gene pairs with non-trivial linear co-expression pattern between oocytes and cumulus cells. Our analyses revealed a complex and functional regulatory circuit between the oocyte and surrounding cumulus cells. Overall design: Transcriptome data was generated from cumulus cells and oocytes from the same cumulus-oocyte complex

卵母细胞（oocyte，雌性配子）在卵泡发生（folliculogenesis）过程中的成熟过程，高度依赖于与体细胞的分子互作。本研究获取了来自窦状卵泡（antral follicles）的单个卵母细胞及其周围卵丘细胞（cumulus cells）的转录组数据（transcriptome data），并构建了一套分析框架以揭示二者的细胞间通讯机制。我们共识别出数百对可在卵母细胞与卵丘细胞间转导旁分泌信号（paracrine signaling）的配体-受体对（ligand-receptors pairs）。部分在卵母细胞及卵丘细胞中表达的编码配体基因（ligand-coding genes），同时也与转录调控（regulation of transcription）功能相关。在卵母细胞或卵丘细胞中表达的编码配体基因，显著富集于一系列生物学功能，这些功能可能与卵丘细胞向卵母细胞膜延伸的跨带突起（transzonal projections）的协同形成相关。最终，我们发现了数千对在卵母细胞与卵丘细胞间呈现显著线性共表达模式的基因对。本研究的分析结果揭示了卵母细胞与其周围卵丘细胞之间存在一套复杂且具备功能的调控环路。整体实验设计：转录组数据来源于同一卵丘-卵母细胞复合体（cumulus-oocyte complex）中的卵丘细胞与卵母细胞。