Endothelial cell therapy to repair the liver vascular network and alleviate liver diseases

About This Grant

ABSTRACT Liver transplantation is the only curative treatment for end-stage and acute liver disease; however, the scarcity of donor organs underscores the urgent need for alternative therapies. Transplantation of human induced pluripotent stem cell (iPSC)-derived liver cells offer a promising approach to treat liver disease. The most desired cell type to transplant is the hepatocyte, the main functional cell of the liver, however, one limitation is the poor maturation of hiPSC-derived hepatocytes that prevent their clinical benefit especially in the case of acute liver diseases that require rapid replenishment of functional hepatocytes. An alternative is to transplant supportive cells that promote proliferation and function of the remaining hepatocytes. We will specifically leverage the known supportive role of liver endothelial cells in animal models for hepatocyte proliferation and function through paracrine signaling during liver repair. The goal of this proposal is therefore to evaluate the therapeutic potential of iPSC-derived endothelial cell (iEC) therapy for promoting liver regeneration in acute liver injury and elucidate the cellular and molecular mechanisms by which iECs support hepatocyte proliferation, repair and function. Using immunocompromised NSG mice, we will apply two complementary acute liver injury models: monocrotaline (MCT)-induced EC-specific damage and acetaminophen (APAP)-induced injury affecting both ECs and hepatocytes. Additionally, the master regulator of EC biology, VEGFA ligand, will be delivered via nucleoside-modified mRNA encapsulated in lipid nanoparticles (mRNA-LNP) to activate in vivo the KDR receptor on iECs, enhancing their engraftment, proliferation, and supportive function. Our preliminary data strongly support this approach: (1) We have established a protocol that efficiently generates a pure population of iECs that are able to engraft after delivery of biologically active VEGFA165 in vivo, and (2) our lab has optimized the mRNA-LNP platform for efficient and transient in vivo VEGFA165 delivery. Based on these data, our central hypothesis is that KDR activation with VEGFA mRNA-LNP in engrafted iECs will enhance their engraftment and restoration of liver function (Aim 1), through supportive endothelial factors that will promote the hepatocyte-iEC niche activation to induce hepatocyte proliferation and function, and hence to promote liver repair (Aim 2). This project will use single-cell RNA sequencing data analyses to identify and further validate critical paracrine factors secreted by iECs that mediate liver regeneration. Altogether, this study will establish the preclinical potential of iEC therapy for acute liver diseases, providing cellular and molecular mechanistic insights in this process and laying the groundwork for potential future applications in chronic liver injury. This research will be conducted at the Center for Regenerative Medicine (CReM) at Boston University, which offers cutting-edge resources for stem cell biology, advanced genomics, and in vivo disease modeling. The training plan integrates rigorous experimental work, mentorship, formal coursework, and professional development activities that will prepare the candidate for a successful academic career.