Thesis Format
Monograph
Degree
Master of Science
Program
Anatomy and Cell Biology
Collaborative Specialization
Developmental Biology
Supervisor
Lala, Peeyush K.
2nd Supervisor
Renaud, Stephen J.
Co-Supervisor
Abstract
The placenta is a temporary organ that forms during pregnancy to support fetal development. Many placental functions are facilitated by trophoblasts, which are divided into subpopulations. The progenitor cytotrophoblasts (CTBs) differentiate into the multinucleated syncytiotrophoblast (STB) and invasive extravillous trophoblast (EVT) lineages. Recently, there has been great interest in developing 3D trophoblast cultures, but the mechanism regulating differentiation remains unknown. This thesis aims to characterize 3D trophoblast cultures and uncover pathways promoting subpopulation development. Trophoblast subpopulation markers were compared between 2D and 3D cultures with human trophoblast stem (TS) cells and immortalized HTR-8/SVneo (HTR) trophoblasts. While changes were limited with HTRs, 3D human TS cultures displayed increased differentiation, predominantly into STB along the periphery. Activation of the Hippo pathway was critical in driving STB formation in 3D human TS cultures. Overall, my thesis suggests that 3D human TS cultures could be a more suitable model for investigating trophoblast biology.
Summary for Lay Audience
During pregnancy, the baby develops within the uterus of the pregnant individual. For this process to occur successfully, a transient organ called the placenta forms to nurture the growth of the baby. The placenta is composed of trophoblast cells that facilitate many of its critical functions. Placental dysfunction can lead to pregnancy complications, such as pre-eclampsia, which threaten the health of babies and pregnant individuals. Unfortunately, the only effective treatment for pre-eclampsia is inducing early delivery of the baby, which can have lifelong impacts. By advancing our understanding of how trophoblast biology differs between healthy and pathological placentas, we may uncover safer treatments that address the root causes of these conditions. However, the applicability of insights from the lab to patients depends on the representativeness of the models employed. One approach to ensure that experimental models better simulate the placenta is incorporating the 3D organization of trophoblasts in cultures. While exciting 3D trophoblast cultures have been created, they have yet to be extensively compared with their 2D counterparts. As such, it is unknown how exactly trophoblasts change between 2D and 3D cultures and which signalling pathways are involved in this process, which my thesis aims to address. Our findings show that trophoblasts in 3D cultures form distinct structures that resemble the placenta. However, this effect in 3D cultures depends on the source of trophoblasts. We also uncovered a signalling pathway between 2D and 3D cultures, whose activation is required for this transformation to occur in trophoblasts. Our next steps include verifying that this signalling pathway is activated within 3D trophoblast cultures and validating that 3D trophoblast cultures can replicate vital placental functions. An exciting application of these 3D trophoblast cultures includes examining the movement of pathogens, drugs, and life-nourishing molecules across the placenta to the baby. Ultimately, the 3D trophoblast cultures better replicate placental structure and may lead to discoveries that improve the outcomes of pregnant individuals and their babies.
Recommended Citation
Zheng, Michael, "Human Trophoblast Differentiation In Vitro Within 3D Matrix-Free Cultures" (2024). Electronic Thesis and Dissertation Repository. 10136.
https://ir.lib.uwo.ca/etd/10136
Creative Commons License
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