Meeting Abstract
P2.93 Saturday, Jan. 5 On the evolutionary origin of endometrial stromal cells KORYU, K.*; LYNCH, V.J.; WAGNER, G.P.; Yale University, Department of Ecology and Evolutionary Biology; Yale University, Department of Ecology and Evolutionary Biology; Yale University, Department of Ecology and Evolutionary Biology koryu.kin@yale.edu
Endometrial stromal cell (ESC) is a fibroblast like cell type from the uterine lining of eutherian mammals. ESCs are essential for establishing novel reproductive traits of eutherian mammals such as prolonged internal gestation and invasive placentation. Whether non-eutherian animals possess a cell type homologous to ESC, and if so what biological roles it has is still unknown. In order to elucidate the evolutionary origin of ESC, we first looked for a homologous cell type in the model marsupial Monodelphis domestica, which belong to the sister group of eutherian mammals. The uteri at different reproductive stages of Monodelphis domestica were obtained and stained for molecular markers which are known to be crucial for the identity of ESCs. The results show that there are cells in the nonpregnant marsupial endometrial stroma which co-express some important markers for ESCs such as HoxA11 and PR. In the pregnant uterus, the number of stromal cells significantly decreases and the distribution of them becomes much narrower, suggesting that their roles in pregnancy are different from those of eutherian ESCs. Secondly, we compared transcriptomes of human mesenchymal cells in an attempt to find the sister cell type of ESC and to elucidate the developmental context in which ESC evolved. Specifically, we collected and compared the mRNA-seq data of various human cell types including chondrocytes, myometrial cells, myofibroblasts, follicular dendritic cells, undifferentiated and differentiated endometrial stromal cells. We found that, among the cell types compared, follicular dendritic cells, which help B-cell maturation in lymph nodes are the closest to ESCs in terms of gene expression. Based on these results we propose a hypothetical model for the evolutionary origin of ESCs.
