Endocytosis of hyaluronidase-1 by the liver.

It has been suggested that intracellular Hyal-1 (hyaluronidase-1), which is considered a lysosomal enzyme, originates via endocytosis of the serum enzyme. To test this proposal we have investigated the uptake and intracellular distribution of rhHyal-1 (recombinant human Hyal-1) by mouse liver, making use of centrifugation methods. Experiments were performed on wild-type mice injected with 125I-labelled rhHyal-1 and on Hyal-1-/- mice injected with the unlabelled enzyme, which were killed at various times after injection.

Lysosomes and Fas-mediated liver cell death.

A number of studies, mostly performed ex vivo, suggest that lysosomes are involved in apoptosis as a result of a release of their cathepsins into the cytosol. These enzymes could then contribute to the permeabilization of the outer mitochondrial membrane; they could also activate effector caspases. The present study aims at testing whether the membrane of liver lysosomes is disrupted during Fas-mediated cell death of hepatocytes in vivo, a process implicated in several liver pathologies.

Hydrodynamics-based transfection of the liver: entrance into hepatocytes of DNA that causes expression takes place very early after injection.

Background: The mechanism of gene transfer into hepatocytes by the hydrodynamics-based transfection procedure is not clearly understood. It has been shown that, after a hydrodynamic injection, a large proportion of plasmid DNA remains intact in the liver where it is bound to plasma membrane and suggested that this DNA could be responsible for the efficiency of the transfection.

Methods: We have investigated the problem by giving mice a hydrodynamic injection of isotonic NaCl, followed at different time intervals by a conventional injection of DNA, cold or labelled with (35)S, with cDNA of luciferase as a reporter gene.

A comparative study of the subcellular distribution of native and deglycosylated gelonin in rat liver and kidney.

Intravenous injection of gelonin and deglycosylated gelonin led to rapid clearance from the blood. Both molecules distributed similarly in liver and kidney suggesting that they followed the same pathway. Deglycosylation reduced the uptake by a third in liver, but did not affect uptake by kidney.

Uptake by mouse liver and intracellular fate of plasmid DNA after a rapid tail vein injection of a small or a large volume.

Background: An efficient gene transfer can be achieved in mouse liver by a rapid tail vein injection of a large volume of plasmid DNA solution (hydrodynamics-based transfection). The mechanism of gene transfer by this procedure is not known. It must be related to the uptake and intracellular fate of DNA.

Uptake and intracellular fate of gelonin, a ribosome-inactivating protein, in rat liver.

Gelonin, a type 1 ribosome-inactivating protein, has been used as toxin conjugate for several therapeutic purposes. We have investigated the endocytosis of gelonin by rat liver in vivo. Subcellular distribution of [125I]gelonin was established after differential and isopycnic centrifugation.