title: Salmonella-mediated delivery of RNase P-based ribozymes for inhibition of viral gene expression and replication in human cells.
abstract: A fundamental challenge in gene therapy is to develop approaches for delivering nucleic acid-based gene interfering agents, such as small interfering RNAs and ribozymes, to the appropriate cells in a way that is tissue/cell specific, efficient, and safe. Using human cytomegalovirus (HCMV) infection of differentiated macrophages as the model, we showed that Salmonella can efficiently deliver RNase P-based ribozyme sequence in specific human cells, leading to substantial ribozyme expression and effective inhibition of viral infection. We constructed a functional RNase P ribozyme (M1GS RNA) that targets the overlapping mRNA region of two HCMV capsid proteins, the capsid scaffolding protein (CSP) and assemblin, which are essential for viral capsid formation. Substantial expression of ribozymes was observed in human differentiated macrophages that were treated with attenuated Salmonella strains carrying the ribozyme sequence constructs. A reduction of 87-90% in viral CSP expression and a reduction of about 5,000-fold in viral growth were observed in cells that were treated with Salmonella carrying the sequence of the functional ribozyme but not with those carrying the sequence of a control ribozyme that contained mutations abolishing the catalytic activity. To our knowledge, this study showed for the first time that ribozymes expressed following targeted gene transfer with Salmonella-based vectors are highly active and specific in blocking viral infection. Moreover, these results demonstrate the feasibility to develop Salmonella-mediated gene transfer of RNase P ribozymes as an effective approach for gene-targeting applications.
authors.affiliation: University of California, Berkeley, CA 94720, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Bai
authors.forename: Hongjian
authors.initials: H
authors.lastname: Li
authors.forename: Gia-Phong
authors.initials: GP
authors.lastname: Vu
authors.forename: Hao
authors.initials: H
authors.lastname: Gong
authors.forename: Sean
authors.initials: S
authors.lastname: Umamoto
authors.forename: Tianhong
authors.initials: T
authors.lastname: Zhou
authors.forename: Sangwei
authors.initials: S
authors.lastname: Lu
authors.forename: Fenyong
authors.initials: F
authors.lastname: Liu
mesh_terms: D002454:Cell Differentiation; D003586:Cytomegalovirus Infections / Q000628:therapy; D005347:Fibroblasts / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D006801:Humans; D007700:Kinetics; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D016337:RNA, Catalytic / Q000737:chemistry*; D043262:Ribonuclease P / Q000737:chemistry*; D012475:Salmonella / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D016337:RNA, Catalytic; D043262:Ribonuclease P