Endocervical trophoblast for interrogating the fetal genome and assessing pregnancy health at five weeks

Prenatal testing for fetal genetic traits and risk of obstetrical complications is essential for maternal-fetal healthcare. The migration of extravillous trophoblast (EVT) cells from the placenta into the reproductive tract and accumulation in the cervix offers an exciting avenue for prenatal testing and monitoring placental function. These cells are obtained with a cervical cytobrush, a routine relatively safe clinical procedure during pregnancy, according to published studies and our own observations. Trophoblast retrieval and isolation from the cervix (TRIC) obtains hundreds of fetal cells with >90% purity as early as five weeks of gestation. TRIC can provide DNA for fetal genotyping by targeted next-generation sequencing with single-nucleotide resolution. Previously, we found that known protein biomarkers are dysregulated in EVT cells obtained by TRIC in the first trimester from women who miscarry or later develop intrauterine growth restriction or preeclampsia. We have now optimized methods to stabilize RNA during TRIC for subsequent isolation and analysis of trophoblast gene expression. Here, we report transcriptomics analysis demonstrating that the expression profile of TRIC-isolated trophoblast cells was distinct from that of maternal cervical cells and included genes associated with the EVT phenotype and invasion. Because EVT cells are responsible for remodeling the maternal arteries and their failure is associated with pregnancy disorders, their molecular profiles could reflect maternal risk, as well as mechanisms underlying these disorders. The use of TRIC to analyze EVT genomes, transcriptomes and proteomes during ongoing pregnancies could provide new tools for anticipating and managing both fetal genetic and maternal obstetric disorders.