Modelling human natural killer cell development and drug response in a microfluidic bone marrow model

Leopold Koenig ^1* Inbal Ben Eliezer ² Thi Phuong Tao ¹ Annika Winter ¹ Moran Grossman ^2*

• ¹ TissUse GmbH, Belrin, Germany
• ² Research and Development, Teva Pharmaceuticals (Israel), Netanya, Israel

The human bone marrow is a complex organ that is critical for self-renewal and differentiation of hematopoietic progenitor cells into various lineages of blood cells. Perturbations of the hematopoietic system have been reported to cause numerous diseases. Yet, understanding the fundamental biology of the human bone marrow in health and disease and during the preclinical stages of drug development is challenging due to the complexity of studying or manipulating the human bone marrow. Human cellbased microfluidic bone marrow models are promising research tools to explore multi-lineage differentiation of human stem and progenitor cells over long periods of time.Here, we describe for the first a time a microfluidic bone marrow model focused primarily on natural killer (NK) cell development. Human hematopoietic stem and progenitor cells were cultured in a lymphoid cultivation medium in coculture with mesenchymal stromal cells on a zirconium oxide ceramic scaffold. The kinetics of differentiation into mature NK cells was traced by flow cytometry over a period of up to seven weeks. Alongside with the NK cells, myeloid cells developed in the system including granulocytes, monocytes and dendritic cells. The differentiated NK cells could be activated after stimulation with phorbol myristate acetate (PMA) and ionomycin indicating the functionality of the cells.Treatment with an anti-IL-15 monoclonal antibody (TEV-53408) induced a reduction in proliferation of late-stage NK progenitor cells as shown by EdU staining. This led to significantly dose dependent reduction in the number of circulating Stage 4 -6 NK cells in the system after one week of treatment. This effect was partially reversible after a two-week treatment-free period.In summary, the presented model enables investigation of human NK cell development in the bone marrow and provides a basis to study related diseases and drug response effects in a microenvironment that is designed mimic human physiology.