Prix de thèse 2026

First, I would like to extend my heartfelt thanks to the French Proteomics Society and its Scientific Committee for awarding me its 2026 Thesis Prize. It was also a pleasure to present my thesis work at ProteoVilamoura, the 6th Joint Congress of the Portuguese, Spanish, and French Proteomics Societies.

None of this would have been possible without the guidance of my thesis supervisor, Thomas Freour, and the support of Arnaud Reignier, Laurent David, Charles Pineau, and the whole PROTIM team. 

My thesis focused on a major public health issue. Currently, one in six couples face infertility, and in-vitro fertilization (IVF) remains the main path forward, yet only around 25% of cycles succeed. Many failures happen at the implantation window, when the embryo attaches to the uterus, a step that current embryo assessment methods, based on morphology alone, cannot reliably predict. My thesis set out to better understand this window at the molecular level, through two complementary projects.

The first project established the first proteomic atlas of human peri-implantation development. Implantation represents a pivotal transition in human embryogenesis, orchestrated by rapid and coordinated molecular reprogramming. In order to better understand the functions involved in human embryo implantation, I developed an integrated multi‑omics strategy combining high‑resolution mass‑spectrometry‑based proteomics, mid‑infrared spectroscopy, single‑cell RNA sequencing, and immunofluorescence to map spatiotemporal protein and metabolic dynamics from pre‑ to post‑implantation. This approach reveals a sharp implantation‑associated breakpoint characterized by coordinated remodeling of adhesion molecules, chromatin regulators, and metabolic enzymes, including extensive reprogramming of lipid and glycan biosynthesis. I further define six stereotyped transcription factor expression archetypes underlying trophectoderm and trophoblast maturation, expand protein‑anchored gene regulatory networks, and functionally dissect ARID3A and GCM1 in human blastoids (3D models of the human blastocyst), showing that each factor controls distinct implantation‑associated adhesion and metabolic programs. Together, these findings establish a mechanistic framework for how human embryos acquire implantation competence and provide a reference resource for blastocyst implantation and early placentation.

The second project turned to a more clinical question: finding a non-invasive protein biomarker that could improve embryo selection and increase the chances of implantation and live birth. This proved challenging because proteins secreted by embryos are scarce and easily masked by the culture medium itself. After optimizing sample preparation for mass spectrometry, I applied the protocol to 45 spent culture media samples collected after embryo transfer, with implantation outcome known for each (17 implantations, 27 failures), and identified fibronectin as a promising candidate. This protein is detected only in the presence of an embryo, and its concentration correlates with implantation success. ELISA tests, which are less expensive, faster and easier to perform, confirmed this result, paving the way for an objective noninvasive method using fibronectin to guide embryo selection in clinical practice.

Alongside this work, I contributed to the Human Proteome Project, helping to characterize, using stem-cell models of human early development, proteins that had never before been identified at the protein level. These results were published in the Journal of Proteome Research. 

Thank you again to the FPS for this distinction, and to everyone who made this research possible.
Océane Girard