Granulosa-cumulus cells global transcriptome sequencing as a predictor of embryo development: a preliminary study.

Background: The aim of this study is to determine the human oocyte CCs global transcriptome sequencing and its correlation of embryo development to the blastocyst-stage.

Methods: Expanded cumulus granulosa cells (CGC) that surround metaphase 2 were collected and cryopreserved until analysis. Their corresponding oocytes trajectories were followed up to the blastocyst stage. From each patient, CGCs of oocyte that developed to the blastocyst stage and one that was arrested (sibling oocytes) were analyzed. Global transcriptome sequencing (NEBNext^® Single Cell/Low Input RNA Library Prep Kit for Illumina) was compared between CGCs of oocytes that developed to the blastocyst stage and those that were arrested.

Results: Seven patients aged 31.4+2.5 years donated CGCs. The Differential Gene Expression Analysis identified five genes that were differentially expressed between blastocyst and arrested CGCs. The most significantly differentially expressed gene was AL031598.1 (padj = 8.40e-03, log2FC = 5.76), followed by AC126773.5 (padj = 1.83e-02, log2FC = 6.63), CBLN2 (padj = 2.62e-02, log2FC = -6.24), AL022721.1 (padj = 3.28e-02, log2FC = 5.73), and AC093334.1 (padj = 8.53e-02, log2FC = 6.07). Among these genes, CBLN2 was the only one showing significant downregulation in the blastocyst group, while the other four genes demonstrated substantial upregulation.

Conclusions: This study provides valuable insights into the transcriptional landscape of CGC from oocytes that develop to different stages, revealing key genes and long non-coding RNAs that may serve as markers for oocyte quality and its potential to develop to the blastocyst stage. Future research with larger cohorts and independent validation methods is necessary to confirm these findings and their potential application in fertility treatments.