Role of Epithelial cadherin in regulating metabolism of pluripotent stem cells

Abstract

Epithelial cadherin (E-cadherin) is the main protein to maintain cell-cell adhesion in pluripotent stem cells. It possesses many roles in both mouse and human pluripotent stem cells. In the mouse, E-cadherin maintains naïve mouse embryonic stem cells (mESCs) pluripotency by regulating LIF/STAT3 pathway signalling. Inhibition of E-cadherin in mESCs leads to profound transcriptomic alterations, increased cell proliferation and a switch from LIF-BMP to Activin/Nodal-dependant pluripotency, akin to a primed pluripotent phenotype. Interestingly, a third of gene transcript changes following inhibition of E-cadherin in mESCs were associated with metabolism, suggesting altered energy production in these cells. E-cadherin is known to play a central role in the successful somatic reprogramming to pluripotency through its role in regulating mesenchymal to epithelial transition. Its loss of expression renders the reprogramming and halts the cells from the acquisition of a pluripotent epithelial phenotype. Recently, metabolic adjustments are reported in both naïve-to-primed switching and during somatic reprogramming to pluripotency. In this project the impact of E-cadherin loss upon the energy production was investigated in mESCs and human induced pluripotent stem cells (hiPSCs) using quantitative MS/MS proteome analysis, network modelling and metabolic functional assays. Proteomic analysis revealed that a third of detected proteins were altered in E-cadherin null ESCs (Ecad-/- mESCs). Network modelling analysis of the proteomic data identified several putative affected pathways associated with mitochondrial respiration and glycolysis. Cellular flux assays of wild-type (Wt) and Ecad-/- mESCs revealed significant alterations in oxidative phosphorylation between the cell types, including a switch in energy production pathways from bivalent to a more glycolytic state. In the hiPSCs, four percent of the proteome was altered due to the transient cell-cell mediated inhibition. E-cad- neutralized cells have inhibited oxidative phosphorylation through the downregulation of complex III and VI subunits of the ETC, decreased their proliferative state and strictly upregulated epithelial to mesenchymal transition markers. In summary, the results show that E-cadherin regulates energy production in pluripotent stem cells and loss of this protein results in altered metabolic behaviour.

Date of Award	1 Aug 2020
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Richard Unwin (Supervisor) & Anne-Marie Glenny (Supervisor)