Determining genetic mechanisms that drive in vitro hematopoiesis - PROJECT SUMMARY/ABSTRACT This proposal focuses on how the Tropomyosin 1 gene product impacts the development of hematopoietic stem and progenitor cells (HSPCs) and their precursors. There is considerable interest in augmenting in vitro HSPC production from cultured induced pluripotent stem cells (iPSCs) to support research and development of blood cell-based therapies. Defining genetic determinants of hematopoiesis is also relevant for understanding benign and malignant blood disorders. We identified Tropomyosin 1 as a blood regulatory gene from human genome wide association study data. We found that Tropomyosin 1 deficiency enhanced production of HSPCs and their hemogenic endothelial precursor cells (HECs) in vitro and in vivo. Using transcriptomic and molecular approaches, we found that Tropomyosin 1 loss enhanced TNFa signaling in cultured iPSCs and further determined that TPM1-related TNFa signaling augmentation was responsible for increased hematopoietic output. In Aim 1 of this grant, we will determine molecular mechanisms for how Tropomyosin 1 and actin biology regulate the TNFa signaling pathway in HECs and HSPCs using translationally relevant iPSC culture models. In Aim 2, we will determine if TPM1 deficiency increases the production of transplantable HSPCs through TNFa-mediated effects on HECs. My goal is to run a laboratory that integrates computational and biochemical approaches to understand genetic mechanisms that enhance blood production, ultimately supporting cell therapeutics and regenerative medicine applications to enhance human health. This proposal directly resulted from completion of the specific aims and achievement of career development goals set forth in my K99 proposal, including rigorous training in data science and hematopoiesis modeling. The three-year professional development program proposed in this R00 application will further propel my research career as an academic pediatric physician-scientist investigating Tropomyosin 1 and other genetic mechanisms that regulate hematopoiesis. Having completed my clinical training and having obtained a tenure-track appointment as an Assistant Professor of Pediatrics at the University of Pennsylvania Perelman School of Medicine, I am well-supported at the institutional level. As I develop my independent research program in this ideal academic environment, I will benefit from the exceptional resources, core facilities, and collaboration with internationally recognized leaders in hematopoiesis, human genetics, bioinformatics, and iPSC technologies at the University of Pennsylvania and Children’s Hospital of Philadelphia for the duration of the R00 award period. After establishing my independent research program with R00 support, I will be uniquely poised to compete for R01 funding as a successful physician-scientist studying hematopoiesis genetics.
