Investigating the role of RICTOR/mTORC2 in regulating self-renewal and differentiation of human embryonic stem cells
File(s)
Author(s)
Batool, Faiza
Type
Thesis
Abstract
The mechanistic target of rapamycin (mTOR) signalling plays crucial roles in controlling mammalian cell behaviour and functions through two distinct multi-protein complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). The mTORC2 complex is not only important for cellular growth and metabolism but is proposed to have a critical role during early embryonic development. Studies showed that mTORC2-knockout mouse embryos either RICTOR or mSin1 (mTOR complex 2 specific protein) die at mid-gestation e10.5-11.5 due to cardiovascular defects. However, much less is known about mTORC2 function in human embryonic development, including its role in human embryonic stem cells.
To understand the role of RICTOR/mTORC2 in early development, RICTOR-KO hESCs have been generated in our lab. In this project, we investigated the role of RICTOR/mTORC2 in early development using RICTOR-knockout human embryonic stem cells (RIC-KO hESCs). Despite being able to maintain their self-renewal and pluripotency, I found that RICTOR depletion led to impaired E-cadherin-mediated cell adhesion and disrupted mesendoderm lineage. Additionally, RIC-KO hESCs displayed increased RhoA activity and disorganized actomyosin structure compared to WT control cells. My data showed that, although RICTOR-knockout human embryonic stem cells (RIC-KO hESCs) can differentiate into all three germ layers via embryoid body formation, they display significantly reduced differentiation into the mesendoderm lineage compared to control cells,
Collectively, results confirm that RICTOR/mTORC2 is not essential for self-renewal and pluripotency of hESCs, but it plays an important role in mesendoderm differentiation and regulates fate acquisition. Further studies to elucidate the molecular mechanism by which RICTOR/mTORC2 regulates the mesendoderm differentiation will provide insights to early embryogenesis and fate determination of human embryonic development.
To understand the role of RICTOR/mTORC2 in early development, RICTOR-KO hESCs have been generated in our lab. In this project, we investigated the role of RICTOR/mTORC2 in early development using RICTOR-knockout human embryonic stem cells (RIC-KO hESCs). Despite being able to maintain their self-renewal and pluripotency, I found that RICTOR depletion led to impaired E-cadherin-mediated cell adhesion and disrupted mesendoderm lineage. Additionally, RIC-KO hESCs displayed increased RhoA activity and disorganized actomyosin structure compared to WT control cells. My data showed that, although RICTOR-knockout human embryonic stem cells (RIC-KO hESCs) can differentiate into all three germ layers via embryoid body formation, they display significantly reduced differentiation into the mesendoderm lineage compared to control cells,
Collectively, results confirm that RICTOR/mTORC2 is not essential for self-renewal and pluripotency of hESCs, but it plays an important role in mesendoderm differentiation and regulates fate acquisition. Further studies to elucidate the molecular mechanism by which RICTOR/mTORC2 regulates the mesendoderm differentiation will provide insights to early embryogenesis and fate determination of human embryonic development.
Version
Open Access
Date Issued
2022-11-27
Date Awarded
2023-03-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Cui, Wei
Sponsor
Punjab Educational Endowment Fund
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)