Identifying molecular markers specific of human embryo development at the protein level is challenging: it requires a lot of time and embryos to validate antibodies. Therefore, only around 30 markers have been established over several decades. We recently performed bulk MS-MS of human embryos from 4 to 10 days post fertilization (d.p.f.), yielding thousands of proteins. The goal is to attempt to attribute proteins to specific fates and developmental stages.

We recently defined cell clusters that reflect the current state of the art from single-cell RNA-Seq data (manuscript in consideration). We aim to leverage these cell clusters to infer specific proteomic signatures associated with developmental fates during human embryo development. To do so, we:

1/ Match single-cell clusters with proteomic bulk samples (e.g.: 8 d.p.f. embryos are composed of the TE/TB NR2F2, D8 EPI and D8 Hypo cells). We then averaged cell clusters expression for each developmental stage.

2/ Restrict averaged expression matrixes to proteins identified via mass spectrometry for each embryonic day.

3/ Investigate the functions of these new markers to elucidate their roles in cell fate progression.

This study infers protein content, identifying a hundred of new state and stage specific markers in human embryo development, validated by proteomic. This refines our knowledge of peri-implantation human embryo development by specifying morula, blastocyst and post-implantation stages molecular signatures. Investigating the roles of those new markers (including transcription factors) and the associated regulons could significantly enhance our understanding of molecular mechanisms underlying cell fate progression around implantation.

These results are highly valuable to associate markers with specific fates and stages of development. This resource will enhance our understanding of human development and guide our subsequent studies, such as knockout experiments and immunofluorescence analysis.