MECHABOOST

Cell culture bioprocesses require a multiscale and multidisciplinary approach: engineering to monitor and create a mechanical, biochemical and physical microenvironment created around the cells, and it requires biological knowledge to correlate the reaction of cells. Around the cell, the microenvironment is can be tuned in different ways (mechanical, physical and biochemical) which impact cell reaction and therefore characteristics. Until recently, cell therapy has been the main option chosen as biomedicine, but recently it is the secretion from the cells (secretome) and more specifically the extracellular vesicles (EVs) that have been shown to have strong therapeutical applications. However, their production for clinical assays requires a large number of cells to obtain a good quantity of biomedicine. In addition, several challenges need to be overcome to have a good quality, yield and quantity of bioproducts. The project MECHABOOST aims to develop bioprocesses for the production of EV where the culture parameters are tuned to obtain from one cell origin, Mesenchymal Stem Cells from Wharton Jelly (WJ-MSC, in the umbilical cord of new-borns), secretome with different bioactivity. The hypothesis is that mimicking a diseased microenvironment for all cues (mechanical, physical and biochemical) around the cells will lead them to produce a specific secretome, and here EVs, to counteract those symptoms. In this project, the design of experiment method will be used to determine different levels of microenvironment to subject the WJ-MSCs to. With a step-by-step approach, first (WP1) the mechanical or biochemical cues will be applied to the cells cultured in 2D on T-flasks. Shear stress will be applied on the cells with a wave shaker (range 1 to 6 Pa), or the pH will be varied (range 7.4 to 6.5). Then, both will be combined to assess if they have a synergic effect on EV production in yield, quality and/or bioactivity. The second step (WP2) will be to translate from a 2D to a 3D configuration which changes the physical microenvironment of the cells by culturing them in a spinner flask (100-200 mL) on a microcarrier or into spheroids, while the 2 other cues are regulated based on the WP1 results. Finally, the last step (WP3) will be a proof of concept, that the culture in the spinner flask can be expanded into 1 L online monitored bioreactors to increase the number of EVs produced. The production of the secretome will be first in 2D culture in T-flask, then in 3D in spinner flasks and then in 3D in the larger bioreactors (> 1 L). At each step, the cell phenotype will be assessed, the EVs will be purified and then characterised (size, content, biomarkers). In addition, their bioactivity will be as well assessed at each step to follow up if they are comparable at each evolution of the scale. The project MECHABOOST is a multidisciplinary and multiscale project that will provide bioprocesses with a high-yield bioproduction of EVs, and obtain from one cell type (here WJ-MSC) a range of bioproducts for different therapeutical applications. In addition, it will create new knowledge in bioprocess engineering and stem cell mechanobiology that will bring forward the fields of biomedicine production and acellular biotherapy.