Speaker
Description
Introduction:
The human bone marrow (BM) is home to Hematopoietic Stem Cells (HSCs) and Bone Marrow Stromal Cells (hBMSCs) which are known to contain skeletal stem cell populations. Whereas the HSC compartment is well characterized, the identity and function of the hBMSC populations remain obscure and requires thorough investigation. A better understanding of the BM and the accommodated cells is crucial as changes in the microenvironment homeostasis may cause severe diseases including leukemia. Recent advances in single cell analysis featured hBMSCs as a heterogeneous cell population with only a small fraction of cells having the potential for multilineage differentiation and long-term self-renewal [1]. To unveil the true fate of hBMSCs we perform cell implantations in vivo to reliably verify their function in the complex native environment.
Methodology:
To reveal the function and hierarchical organization of distinct hBMSC subpopulations we propose to engineer a multiplexing screening device for efficient in vivo testing. Additionally, using transglutaminase crosslinked poly(ethylene glycol) (PEG) hydrogels we are establishing robust microenvironmental conditions for the osteo-, chondro- and adipogenic differentiation of hBMSCs. Then, we will encapsulate prospectively isolated hBMSC populations in defined microenvironments and place them in the implantable multiplexing device. Finally, multiplexing devices will be implanted in subcutaneous pouches of immune-deficient mice and used to assess the in vivo differentiation capacity of candidate subpopulations of hBMSCs.
Results:
First experiments dedicated to minimize the number of required hBMSCs and increasing the number of test conditions have revealed in vivo differentiation in an osteogenic microenvironment and formation of small bone ossicles containing a hematopoietic niche within the multiplexing device.
Conclusion:
In this project, we develop a multiplexing platform to screen hBMSC behavior in vivo in a higher throughput manner. We will optimize the designs for multiplexed testing of health and disease-related low-abundant hBMSC subpopulations, requiring minimal cell numbers and tiny hydrogel volumes. The results of this project will constitute an important foundation to study human BM stromal hierarchy and elucidate the functional role of individual hBMSC subpopulations.
References:
[1] Chan, C. K. et al., Cell, 175(1), 43-56 (2018).
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