Molecular evolution of synthetic Adeno-associated viral (AAV) vectors in an artificial microvascular liver system and their use for cell-specific gene knockdown/knock-out
The human liver is a vital, large and complex organ that is composed of a variety of different cell types, most notably, hepatocytes, liver sinusoidal endothelial cells, Kupffer cells (liver-resident macrophages) and stellate cells. Due to its key role in normal metabolism and in genetic, acquired or infectious diseases, there is a great demand for novel ex vivo organotypic model systems that faithfully recapitulate the multi-cellular composition of the human liver, and that allow to study and to deliberately perturb the physiological interaction of the various cell types. In parallel, emerging clinical data showcase the potential of in vivo gene therapies in the liver, especially when using recombinant vectors based on apathogenic Adeno-associated viruses (AAV) for gene transfer. Fueling this enthusiasm is that AAV vectors can be genetically engineered to deliver the components of two powerful techniques for gene regulation, RNA interference (RNAi) and genome editing (CRISPR), implying options to create new classes of gene therapeutics to treat a wealth of hepatic diseases. Towards these seminal aims, the labs of Prof. Ute Schepers (KIT) and Dr. Dirk Grimm (Heidelberg University) will team up and synergistically combine their profound and unique expertises, tools and technologies. This includes a novel, dynamic, 3D organotypic liver model comprising an artificial microvasculature (μ3DVasc) coated by liver sinusoidal endothelial cells and surrounded by a 3D compartment for culture of multiple hepatic cell types (Schepers lab). It moreover includes a large collection of natural and synthetic AAV capsids as well as of AAV genomes permitting combinatorial RNAi and/or CRISPR expression (Grimm lab). The aims of this project are to harness these AAV capsids/genomes for efficient modulation of specific cell types in the new ex vivo liver model, and, vice versa, to exploit this model to further evolve and fine-tune AAV vectors for future clinical use in the human liver.