Release and uptake of lysosomal enzymes : studied in cultured cells

The purpose of the experimental work described in this thesiswas to investigate some aspects of the release and uptake of lysosomal enzymes. The experiments involved the use of normal human and animal fibroblasts and some other cell types such as hepatocytes and hepatoma cells as sources of hydrolytic enzymes, and fibroblasts from patients with lysosomal storage diseases associated with a single lysosomal enzyme deficiency and with "1-cell" disease as recipient cells. In a number of studies co-cultivation of normal and mutant cells was applied. as a means to study the release and uptake of lysosomal enzymes at physiological concentrations. We have also studied some characteristics of released lysosomal enzyme activities in· normal and mutant cell cultures in comparison with the corresponding intracellular activities. Finally, we have used somatic cell hybridization to investigate the genetic background of the metabolic abnormalities in some of the human mutant cells. Our studies have provided information on the normal transport of lysosomal enzymes within the cell and between cells. Furthermore, we hope that more knowledge about recognition and uptake of lysosomal enzymes by deficient cells from patients with lysosomal storage diseases will have future implications for enzyme therapy.