(F1128) HEPATOCYTE GROWTH FACTOR AND EPIDERMAL GROWTH FACTOR DELIVERED VIA MRNA IN LIPID NANOPARTICLES IMPROVE ENGRAFTMENT OF HUMAN PRIMARY AND IPSC-DERIVED HEPATOCYTES IN MICE
PhD Student Boston Univeristy School of Medicine, United States
Abstract: Thousands of patients die each year awaiting liver transplantation due to end-stage liver failure. To address the scarcity of donors, transplantation of primary human hepatocyte (PHH) or induced pluripotent stem cell (iPSC) derived hepatocyte-like cells (iHeps) is explored as alternative therapies to restore liver function. However, cell therapies are constrained by limiting factors such as low efficiency of engraftment and rejection. Our lab addresses these issues by the establishment of a clinically relevant injury mouse model and stimulation of key liver regeneration pathways in transplanted cells. Our mouse model is the NSG-PiZ mouse which recapitulates human alpha-1 antitrypsin deficiency (AATD)-associated liver disease, a genetic disease that can lead to liver failure. We precondition NSG-PiZ mice with AAV8-TBG-p21 to express the cell-cycle inhibitor p21 under the hepatocyte specific thyroxine binding globulin (TBG) promoter to recapitulate p21-induced hepatocyte senescence observed in virtually all AATD patients. Survival and proliferation of transplanted cells are significantly promoted by the delivery of hepatocyte mitogens such as human hepatocyte growth factor (HGF) and epidermal growth factor (EGF) using safe and non-integrative nucleoside-modified mRNA encapsulated in lipid nanoparticles (mRNA-LNP). We demonstrate that the combination of HGF and EGF mRNA-LNP leads to 30% repopulation of the NSG-PiZ/p21 mouse livers by PHH and significantly reduces AATD liver disease burden. iHep cell therapy is an attractive alternative to PHH therapy as it eliminates the need for a donor and generation of iHep from human iPSC has the advantage to provide an unlimited supply of patient-specific hepatocytes. Therefore, we established an efficient iHep differentiation protocol which results in a near 100% of FOXA2+ HNF4a+ hepatic endoderm derivatives with up to 94% expressing AFP by day 10. Transplantations of luciferase-expressing iHeps show sustained engraftment in HGF+EGF mRNA-LNP-treated NSG-PiZ/p21 over 4 weeks as assessed with bioluminescence compared to that in control mice injected with control mRNA-LNP and AAV-TBG-Null. These findings improve our knowledge of the mechanisms that underlie liver repair and advance the search for donor-free cell therapies for liver failure.
Funding Source: R01DK124361 and Alpha one foundation research award to Valerie Gouon-Evans, and F31DK135378 to Anna Smith
