Protein transduction domains have been used to deliver a variety of biologically active cargo across cellular membranes.
However, the potential of protein transduction domains to mediate transport of nanoparticular structures into the cytoplasm bypassing the endosomal compartment remains unclear.
Dr Eberhard Hildt and colleagues from Germany established cell-permeable virus-like particles harboring a marker gene.
The gene was based on Hepatitis B virus nucleocaspids.
Cell permeability was achieved by fusion with translocation motif-protein transduction domains.
|A gene transfer efficiency of approximately 95% was observed|
The research team used electron and confocal microscopy.
The team revealed that these virus-like particles translocate as complete particles across the plasma membrane and transverse the cytoplasm toward the nucleus.
The researchers found that the inhibition of endocytosis did not affect translocation of these virus-like particles into the cytoplasm.
Based on these particles, a gene transfer system was developed.
To this end the particles were loaded with DNA-encoding small Hepatitis B virus surface antigen or green fluorescence protein that served as marker genes.
The researchers noted that the DNA-packaging efficiency was very low.
Applying the appropriate number of virus-like particles to primary human hepatocytes, the team observed a gene transfer efficiency of approximately 95%.
Dr Hildt's team concluded, “The translocation motif-protein transduction domains has the potential to mediate efficient transfer of assembled particles and its cargo, nucleic acids, into primary human hepatocytes.”
“This provides the basis for development of novel transducible therapeutic or diagnostic particles.”