Exploring the molecular underpinnings of macrosomia in gestational diabetes mellitus: The role of EGFR signaling and placental syncytiotrophoblast.

Macrosomia, which is frequently associated with gestational diabetes mellitus (GDM), is linked to maternal glycemic control during gestation. When GDM is complicated by macrosomia (GDMM), the placenta exhibits increased mass, underscoring its role as a critical nexus for maternal-fetal nutrient exchange. Despite this recognized correlation, the underlying mechanisms propelling placental hypertrophy have remained elusive. Our study leveraged single-cell RNA transcriptome sequencing of GDMM placental tissues to pinpoint the specific syncytiotrophoblast (SCT) subsets that regulate placental dimensions. Notably, we observed pronounced upregulation of the epidermal growth factor receptor (EGFR) and its corresponding ligands, with a particular emphasis on the autoregulatory cascade involving the glycoprotein hormone alpha subunit (CGA), EGFR, and the transcription factor GATA binding protein 2 (GATA2), as well as perturbations in hormonal homeostasis within the SCT. Furthermore, our cell interaction analysis revealed an enhanced interplay between myeloid cells and SCT3, augmenting the EGFR signaling pathway. These molecular exchanges underscore the pivotal role of the placental immune microenvironment in the etiology of macrosomia, shedding light on the pathophysiology of GDMM and paving the way for novel therapeutic approaches.