Abstract
Human hematopoietic stem cells (HSCs) reside in the bone marrow (BM) niche, an intricate, multifactorial network of components producing cytokines, growth factors, and extracellular matrix. The ability of HSCs to remain quiescent, self-renew or differentiate, and acquire mutations and become malignant depends upon the complex interactions they establish with different stromal components. To observe the crosstalk between human HSCs and the human BM niche in physiological and pathological conditions, we designed a protocol to ectopically model and image a humanized BM niche in immunodeficient mice. We show that the use of different cellular components allows for the formation of humanized structures and the opportunity to sustain long-term human hematopoietic engraftment. Using two-photon microscopy, we can live-image these structures in situ at the single-cell resolution, providing a powerful new tool for the functional characterization of the human BM microenvironment and its role in regulating normal and malignant hematopoiesis.
Highlights
Cell fate decisions observed in stem cell compartments are tightly regulated by both intrinsic and extrinsic factors
Here we describe how the coimplantation of other human bone marrow (BM) cellular components, such as human endothelial cells, and/or cytokines important for bone formation, cooperate with hMSCs to generate different humanized microenvironments, which can be live-imaged in situ
The co-seeding of human ECs with hMSCs in the scaffold allows for the formation of more relevant vasculature in scaffolds (Figure 2B)
Summary
Cell fate decisions observed in stem cell compartments are tightly regulated by both intrinsic and extrinsic factors. Merging biomaterials and cell-implantation concepts, reports have shown the feasibility of mimicking the human bone marrow microenvironment in heterotopic regions[23,24,25,26,27] This opens the possibility of using bioengineering in mouse models to study human normal and malignant hematopoiesis[28,29,30,31,32,33,34,35,36,37,38,39], tumorigenesis, and metastasis[40,41,42,43,44]. Based on previous experience in bone tissue engineering and in vivo imaging[19,22,45,46,47,48,49,50,51,52], we describe a protocol to bioengineer and live-image organotypic human BM tissues These structures originate from the implantation of human BM-derived stromal cells into collagenbased scaffolds subcutaneously grafted in immunodeficient mice.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
