Citation: Gao, F., Thompson, J. R., Petsios, E., Erkenbrack, E., Moats, R. A., Bottjer, D. J., & Davidson, E. H. (2015). Juvenile skeletogenesis in anciently diverged sea urchin clades. Developmental biology, 400(1), 148-158.
Decidualization of Human Endometrial Stromal Fibroblasts is a Multiphasic Process Involving Distinct Transcriptional Programs
Decidual stromal cells differentiate from endometrial stromal fibroblasts (ESFs) under the influence of progesterone and cyclic adenosine monophosphate (cAMP) and are essential for implantation and the maintenance of pregnancy. They evolved in the stem lineage of placental (eutherian) mammals coincidental with the evolution of implantation. Here we use the well-established in vitro decidualization protocol to compare early (3 days) and late (8 days) gene transcription patterns in immortalized human ESF. We document extensive, dynamic changes in the early and late decidual cell transcriptomes. The data suggest the existence of an early signal transducer and activator of transcription (STAT) pathway dominated state and a later nuclear factor kB (NFKB) pathway regulated state. Transcription factor expression in both phases is characterized by putative or known progesterone receptor (PGR) target genes, suggesting that both phases are under progesterone control. Decidualization leads to proliferative quiescence, which is reversible by progesterone withdrawal after 3 days but to a lesser extent after 8 days of decidualization. In contrast, progesterone withdrawal induces cell death at comparable levels after short or long exposure to progestins and cAMP. We conclude that decidualization is characterized by a biphasic gene expression dynamic that likely corresponds to different phases in the establishment of the fetal–maternal interface.
Conserved regulatory state expression controlled by divergent developmental gene regulatory networks in echinoids
Evolution of the animal body plan is driven by changes in developmental gene regulatory networks (GRNs), but how networks change to control novel developmental phenotypes remains in most cases unresolved. Here we address GRN evolution by comparing the endomesoderm GRN in two echinoid sea urchins, Strongylocentrotus purpuratus and Eucidaris tribuloides, with at least 268 million years of independent evolution. We first analyzed the expression of twelve transcription factors and signaling molecules of the S. purpuratus GRN in E. tribuloides embryos, showing that orthologous regulatory genes are expressed in corresponding endomesodermal cell fates in the two species. However, perturbation of regulatory genes revealed that important regulatory circuits of the S. purpuratus GRN are significantly different in E. tribuloides. Thus for instance mesodermal Delta/Notch signaling controls exclusion of alternative cell fates in E. tribuloides but controls mesoderm induction and activation of a positive feedback circuit in S. purpuratus. These results indicate that the architecture of the sea urchin endomesoderm GRN evolved by extensive gain and loss of regulatory interactions between a conserved set of regulatory factors that control endomesodermal cell fate specification.
© 2016 Eric M Erkenbrack and Elsevier. All rights reserved.