Probing human HSC genesis in a flow-directed 3D hemogenic vascular niche model

Title: Probing human HSC genesis in a flow-directed 3D hemogenic vascular niche model Project Summary/Abstract: Human induced pluripotent stem cells (PSCs) represent a promising and essentially limitless source of hematopoietic stem, progenitor, and terminally differentiated blood cells for a variety of “off-the-shelf” cellular therapies and disease modelling applications. However, a major obstacle to translating this promise to the clinic is that current protocols for differentiating blood cells from PSCs have not clearly defined the microenvironmental niche signals necessary to support the emergence of functionally transplantable and durably self-renewing hematopoietic stem cells (HSCs). We hypothesize that distinct biochemical signals and fluid mechanical forces specific to the aortic vascular niche, where HSCs first emerge, synergize to promote HSC fate from hemogenic endothelial cell (HEC) precursors. Our preliminary studies suggest a potential novel role for signals transduced downstream of hydrostatic pressure in establishing self-renewal programs essential to HSC fate. We have recently developed a 3D engineered hemogenic vascular niche which supports the induction of hematopoietic fates from PSC-derived endothelium. The primary objective of this proposal is to leverage this innovative platform to test how intrinsic arterial maturation, biomechanical forces, and mesoderm-derived growth factors synergize to promote HSC genesis ex vivo. We propose that replicating the temporal and spatial integration of synergistic biochemical and biomechanical factors will be critical to elucidating the mechanisms by which HSCs can efficiently and reproducibly be derived from PSCs. To accomplish the goals of this proposal, we will leverage the complementary expertise of MPIs Dr. Hadland and Dr. Zheng along with the state-of-the-art techniques available in their laboratories. We expect that success in these goals will accelerate the clinical translation of PSC technologies to advance cellular therapies and disease modelling applications for various blood and immune disorders.