Therapeutic liver cell transplantation to treat a genetic liver defect

Abstract

AbstractFor gene therapy of the liver,in vivoapplications based on adeno-associated virus are the most advanced vectors despite limitations, including low efficacy and episomal loss, potential integration and safety issues, and high production costs. Alternative vectors and/or delivery routes are of high interest. The regenerative ability of the liver bears the potential forex vivotherapy using liver cell transplantation for disease correction if provided with a selective advantage to expand and replace the existing cell mass. Here we present such treatment of a mouse model of human of phenylketonuria (PKU). Primary hepatocytes from wild-type mice were gene modifiedin vitro(with a lentiviral vector) that carries a gene editing system (CRISPR) to inhibitCypor.Cyporinactivation confers paracetamol (or acetaminophen) resistance to hepatocytes and thus a growth advantage to eliminate the pre-existing liver cells upon grafting (via the spleen) and exposure to repeated treatment with paracetamol. GraftingCypor-inactivated wild-type hepatocytes into inbred young adultenu2(PKU) mice, followed by selective expansion by paracetamol dosing resulted in replacing up to 5% of cell mass, normalization of blood phenylalanine and permanent correction of PKU. Hepatocyte transplantation offers thus an armamentarium of novel therapy options for genetic liver defects.