TOWARDS A THERAPEUTIC CORRECTION OF AUTOPHAGIC FLUX IN AN NCL MODEL
Prof. Dr. rer. nat. Paul Saftig
One of the major hallmarks in NCLs is a defect in lysosomal proteolysis leading to neuronal accumulation of autophagic vacuoles. Our preclinical CLN10 model (cathepsin-D-deficient mice) shows all symptoms and pathologies including the development of blindness, ceroid lipopigment storage, block of autophagy, disturbed lysosome protein degradation followed by astrogliosis and neurodegeneration. Recombinantly expressed human cathepsin-D will be generated in CHO and insect cells. The enzyme will be applied to cathepsin-D-deficient cells and uptake and endocytotic route will be characterized by biochemical and microscopy-based techniques. Half-life of recombinant cathepsin-D in serum and its presence, maturation and activity in tissues will be determined. Importantly, we will study the consequences of the delivery of cathepsin-D in order to obtain a therapeutic effect. An important aspect is if enzyme replacement will lead to a prolongation of the life span of this mouse model. We will also analyse the correction of retinal atrophy, lysosomal ceroid accumulations and the degree of autophagy. Our subproject complements the goals of the other projects in the NCL2TREAT consortium and it will set the base for a new therapy of the disease which could be quickly adapted to first clinical trials.