Role of cellular FKBP52 protein in hydroxyurea treatment-mediated increase in transduction efficiency of recombinant adeno-associated virus 2 vectors / 中国药理学通报

ABSTRACT

Aim To explore the role of cytoplasmic FKBP52 in AAV-mediated transduction.Methods Murine embryo fibroblasts(MEFs)cultures from FKBP52 wild-type(WT),heterozygous(HE),and knockout(KO)mice were established.The role of FKBP52 in intracellular trafficking of AAV was analyzed by fluorescence-activated cell sorting(FACS)analyses,electrophoretic mobility shift assays(EMSA),southern blot,immunoprecipitations and western blot analyses.Results Conventional AAV vectors failed to transduce WT MEFs efficiently,and the transduction efficiency was not significantly increased in HE or KO MEFs.AAV vectors failed to traffick efficiently to the nucleus in these cells.Treatment with hydroxyurea(HU)increased the transduction efficiency of conventional AAV vectors by～25-fold in WT MEFs,but only by～4-fold in KO MEFs.The use of self-complementary AAV(scAAV)vectors,which bypass the requirement of viral second-strand DNA synthesis,revealed that HU treatment increased the transduction efficiency～23-fold in WT MEFs,but only～4-fold in KO MEFs,indicating that the lack of HU treatment-mediated increase in KO MEFs was not due to failure of AAV to undergo viral second-strand DNA synthesis.Following HU treatment,～59% of AAV genomes were present in the nuclear fraction from WT MEFs,but only ～28% in KO MEFs,indicating that the pathway by which HU treatment mediates nuclear transport of AAV was impaired in KO MEFs.When KO MEFs were stably transfected with an FKBP52 expression plasmid,HU treatment-mediated increased in the transduction efficiency was restored in these cells,which correlated directly with improved intracellular trafficking.Intact AAV particles were also shown to interact with FKBP52 as well as with dynein,a known cellular protein involved in AAV trafficking.Conclusion These studies suggest that FKBP52,being a cellular chaperone protein,facilitates intracellular trafficking of AAV,which has implications in the optimal use of recombinant AAV vectors in human gene therapy.