Uncover the Interplay Between Signalling Dynamics and Cell Mechanics During Early Fate Acquisition in Human Induced Pluripotent Stem Cells
Human induced pluripotent stem cells (hiPSCs), considered as in vitro equivalent of human epiblast, are a powerful model to study mechanisms underlying embryonic germ layer differentiation. Regulation of hiPSC fate change relies on dynamic interactions between physical and biochemical cues. We have shown that disruption of the hiPSC epithelial organization permits perception of differentiation signals by hiPSCs and the lineage differentiation process. Building on this knowledge, we will explore how mechanical cues
mediated by cell-‐cell contacts and substrate stiffness crosstalk with signals to regulate hiPSCs lineage determination. We will follow molecular/cellular characteristics and correlate them with biophysical properties investigated using optical tweezer micromanipulation, traction force (TFM) and atomic force microscopy (AFM). We will grow hiPSCs as conventional conditions and as micropatterned colonies. In the latter simultaneous differentiation of the three germ layers in a spatially organized profile permits assessing whether and how changes in physical cues impact on germ layer patterning.
Engineered cellular microenvironments, matrix mechanics, cell–cell interactions, cell–matrix interactions, mechanical cues influence on cellular response to morphogens, force generation, microfluidics
Question: how changes in mechanical properties of the hiPSC epithelial sheet (mainly focusing on matrix stiffness) modify response to biochemical signals (BMP4, ACTIVIN, WNT) regulating hiPSCs fate acquisition. Approach: interdisciplinary strategy integrating molecular and cellular biology, biochemistry and classical microscopy with quantitative imaging (reporter hiPSCs lines), and biophysics (micromanipulation, micropatterning, TFM) to collect and correlate biological and mechanical measurements of hiPSCs states.
Candidates are expected to have strong motivation to bridge biology to physics, and must have a strong background in cellular biology, physics or biophysics. Experience in culture cells, microscopy techniques and image processing will be favorably considered. English is the working language.
Continuation of an existing project
This project builds on our work showing that hiPSCs downregulated for the morphogen regulator, GLYPICAN4, have unique cell-‐cell contact organization, with foci of apical constrictions. Their disrupted epithelial organization favors morphogen signal perception and lineage differentiation. Our results uncover GLYPICAN4 mutant hiPSCs as the first in vitro system to study changes in apical membrane size. The new project will investigate relationships between hiPSC mechanics, signaling responses and differentiation.
Articles related to the project
Vining, K., Mooney, D. Mechanical forces direct stem cell behaviour in development and regeneration. Nat Rev Mol Cell Biol 18, 728–742 (2017).
Irawan V, Higuchi A, and Ikoma T. Control of Stem Cell Fate by Physical Interactions with the Extracellular Matrix. Cell Stem Cell 5, 17-‐26 (2009).
Yousafzai MS, Coceano G, Bonin S, Niemela J, Scoles G, Cojo D. Investigating the effect of cell substrate on cancer cell stiffness by optical tweezers. J Biomech 60, 266-‐269 (2017).
Fico A, de Chevigny A, Melon C, Bohic M, Kerkerian-‐Le Goff L, Maina F, *Dono R, *Cremer H. *shared last authors. Reducing Glypican-‐4 in ES Cells Improves Recovery in a Rat Model of Parkinson's Disease by Increasing the Production of Dopaminergic Neurons and Decreasing Teratoma Formation. J Neurosci. 34, 8318–8323 (2014).
Fico A, De Chevigny A, Egea J, Bosl MR, Cremer H, Maina F, and Dono R. Modulating Glypican4 suppresses tumorigenicity of embryonic stem cells while preserving self-‐renewal and pluripotency. Stem Cells 30, 1863-‐1874 (2012).