Remodeling the Fetal Membranes: A New Way to Examine the Mechanisms of Rupture
The overall goal of Claire Wright’s work is to study the mechanisms involved in the remodeling of the fetal membranes to understand the normal mechanisms involved in parturition and to improve the rates of premature preterm rupture of the fetal membranes. She has been building new tools so that her work provides a versatile three-dimensional model of the human amnion that can be used to study the influence on, and interaction with, its resident cells and their extracellular matrix. Thus her work is focused in three main areas that are designed to make rapid progress in the field of fetal membrane rupture.
Firstly, she is working to solve the technical issues limiting the study of the human fetal membranes at term by developing a rapid screening test to assess the viability of clinical samples. In order to understand the mechanisms of fetal membrane weakening as part of human parturition, human fetal membrane tissue is collected at delivery. Although it is relatively easy to collect anonymous human tissue after elective cesarean section, cells isolated from these tissues are often not viable, as they frequently they fail to adhere and proliferate sufficiently to be used in downstream assays. Therefore, developing a viability assay as part of the clinical sample collection protocol provides the ability to swiftly dismiss or accept samples. As these cells from the amnion have also been demonstrated to have varied cell linage marker expression, she is also actively studying the pluripotent characteristics of amnion cells. In addition to the problems often experienced growing cells from the amnion in culture, there have been several reports that indicate that amnion cells isolated from human fetal membranes have pluripotent capacity and therefore should be considered stem cells. Thus characterizing the pluripotency of these cells provides novel data that can influence mechanistic studies aimed at understanding membrane rupture by providing the ability to recognize the potential for transformation/differentiation in culture, identify the presence of different cell sub-populations and obtain a baseline of cell marker characteristics. Indeed, this research focus adds to the current body of knowledge on the characteristics of these cells in the field of parturition research but also stem cell research.
The second focus of her current research is the evaluation of a newly conceived three-dimensional model of the amnion layer of the fetal membranes. Studies from other fields of biology clearly demonstrate the value of culturing cells in 3D conditions by showing that cells behave differently when cultured in 3D conditions in a variety of matrices compared to 2D environments. Cells grown under these conditions exhibit specific morphological and functional characteristics that are more similar to what is seen in live humans than traditional 2D culture. Therefore, she is comparing the behavior, morphology and viability of cells in 2D and 3D tissue culture, to validate this 3D approach as model for the amnion. This provides an extremely novel way to study the interaction of these cells with their surrounding Extra Cellular Matrix (ECM) that enables the study of the mechanisms of the weakening of the fetal membranes in a completely original way and greatly increases the sophistication of future experiments in the field.
Her final research focus area is to study the interaction of cells from the human amnion with their ECM to determine the importance of the resident cells of this layer of tissue in ECM metabolism. In addition, as these cells are vulnerable to apoptosis towards the end of pregnancy, ECM triggers of cellular signaling that promote cell survival are also being investigated. This focus of research is critical to improve our understanding of the mechanisms of fetal membrane rupture as it is generally accepted that the two processes of ECM breakdown and apoptosis are central to the weakening that occurs prior to membrane rupture both at term and preterm. However, to date, there has been no way to study the progression of these two processes in this tissue and thus the data that have established this dogma is almost entirely descriptive. These experiments are the first of their kind to study the interaction of human amnion cells surrounded by their ECM. This has not been possible to date because the cells in explants from these tissues rapidly die in culture, and their ECM has degraded by the end of gestation. These experiments are also be the first to attempt to directly tie together these two biological processes showing that they are directly related and that they represent a feed-forward mechanism for the progression of membrane weakening.
It is expected that this body of work will make a significant contribution to the field of parturition research by addressing the lack of versatile models that allow for sophisticated approach due to limitations of working with tissue that is only ever collected at the end of gestation. Moreover, it is thought that this work will be able to be extended to not only develop new biomarkers to understand the mechanisms behind pPROM and identify those at risk, but also to help develop potential tissue patch technology to provide repair strategies for the fetal membranes after rupture.
INBRE III Research Project Presentation (21 min)
September 21, 2013
John A. Burns School of Medicine