title: Endocytic processing of adeno-associated virus type 8 vectors for transduction of target cells.
abstract: We investigated the transduction of HEK293T cells permissive to adeno-associated virus serotype 8 (AAV8) to understand the mechanisms underlying its endocytic processing. Results showed that AAV8 enters cells through clathrin-mediated endocytosis followed by trafficking through various endosomal compartments. Interestingly, compared to the relatively well-characterized AAV2, a distinct involvement of late endosomes was observed for AAV8 trafficking within the target cell. AAV8 particles were also shown to exploit the cytoskeleton network to facilitate their transport within cells. Moreover, the cellular factors involved during endosomal escape were examined by an in vitro membrane permeabilization assay. Our data demonstrated that an acidic endosomal environment was required for AAV2 penetration through endosomal membranes and that the cellular endoprotease furin could promote AAV2 escape from the early endosomes. In contrast, these factors were not sufficient for AAV8 penetration through endosomal membranes. We further found that the ubiquitin-proteasome system is likely involved in the intracellular transport of AAV8 to nucleus. Taken together, our data have shed some light on the intracellular trafficking pathways of AAV8, which, in turn, could provide insight for potentializing AAV-mediated gene delivery.
authors.affiliation: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: K-I
authors.initials: KI
authors.lastname: Joo
authors.forename: P
authors.initials: P
authors.lastname: Wang
mesh_terms: D001692:Biological Transport; D002467:Cell Nucleus / Q000378:metabolism / Q000821:virology; D002966:Clathrin / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism / Q000821:virology; D000229:Dependovirus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism / Q000821:virology; D045683:Furin / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics / Q000493:pharmacokinetics*; D057809:HEK293 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism / Q000821:virology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D015398:Signal Transduction; D013045:Species Specificity; D014161:Transduction, Genetic / Q000379:methods; D025801:Ubiquitin / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism / Q000821:virology
chemical_list: D002966:Clathrin; D025801:Ubiquitin; D045683:Furin; D046988:Proteasome Endopeptidase Complex