620: Human trophoblast progenitor cell (TBPC) lines derived from aneuploid placentas: studying fundamental aspects of trophoblast biology

Trophoblast (TB) invasion is tightly regulated, and abnormal invasion is linked with pregnancy complications such as miscarriages, pre-eclampsia, IUGR, but the underlying mechanisms are not well understood. Studying aneuploid cell lines might improve the understanding of the biological drivers of normal TB self-renewal/differentiation. The most common trisomies (Trisomy 13, Trisomy 18, Trisomy 21) were studied. Three TBPC lines from each trisomy and 3 age-matched euploid cell lines were established from placentas (GA: 14-22 wks) using methods previously described. Cells expressing the TBPC marker Integrin-α4 were isolated using FACS. Standard Karyotyping was used for ploidy confirmation at different stages. Global transcriptional profiling was used to compile genes that were differentially expressed (DE (≥ 2-fold). Statistical significance was set at log odds-ratio of B statistic >0. Stage-specific antibodies were used to assess self-renewal/differentiation process. Microarray analysis identified many genes as DE in each trisomy: T21(n = 52), T18(n = 100), and T13(n = 29). The DE genes were not only located on the affected chromosome, but also on other chromosomes, suggesting genome-wide effects (Fig.1). ADAMTS5 was the most highly up-regulated gene in T13 & T21, (6 &12-fold, respectively). TGFBR1, a major regulator of cell fate, was the most highly up-regulated in all the trisomies (T13: 2-fold,T18: 2-fold & T21: 3-fold). Transcriptional activator MycT1 expression was down-regulated by 8-fold in T13 &T21. Transcriptional analyses of these cells revealed the dysregulated expression of molecules involved in vasculogenesis, epithelial-to-mesenchymal transitions and invasion. The stage-specific markers in the isolated cells reacted with antibodies recognizing: CK7, an unique TB marker, Geminin, a transcription regulator that is required for TB fate specification and/or differentiation, HMGA2 a marker of TB self-renewal and HLA-G, expressed in invasive TB (Fig.2). These novel and genetically stable aneuploid cell lines are a powerful tool for improving our knowledge of developmental processes and the molecular consequences of the most common aneuploidies, especially in humans where in vivo experimentation is not possible.View Large Image Figure ViewerDownload Hi-res image Download (PPT)