title: Non-cell-autonomous effects of vector-expressed regulatory RNAs in mammalian heart cells.
abstract: In mammalian cells, small regulatory RNA molecules are able to modulate gene expression in a cell-autonomous manner. In contrast, this mechanism of gene regulation can occur systemically in plants and nematodes. The existence of similar cell-to-cell transmission in mammalian cells has been explored, but generalizibilty and mechanistic insights have remained elusive. Here, we show that small regulatory RNA molecules are capable of a non-cell-autonomous effect between primary cardiac myocytes through a gap-junction-dependent mechanism. Co-culture experiments showed that both Dicer-processed small-interfering RNAs (siRNAs) and Drosha-processed microRNAs (miRNAs) were capable of target gene knockdown and physiological effects in a non-cell-autonomous manner. Target gene siRNA molecules were detected in recipient cells, indicating transfer of the primary effector molecule. All of these effects were abrogated by dominant-negative molecular suppression of gap junction function. Our results show that both siRNAs and miRNAs are capable of a non-cell-autonomous effect between mammalian cells through gap junctions. The recognition of this biological process raises the novel therapeutic prospect of a bystander effect after gene transfer to tissues bearing gap junctions and for cell engineering with a view to creating regulatory RNA donor cells that exert their influence throughout a syncytium.
authors.affiliation: Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
authors.forename: E
authors.initials: E
authors.lastname: Kizana
authors.forename: E
authors.initials: E
authors.lastname: Cingolani
authors.forename: E
authors.initials: E
authors.lastname: Marbán
mesh_terms: D000818:Animals; D018920:Coculture Techniques; D017629:Gap Junctions / Q000235:genetics; D055785:Gene Knockdown Techniques / Q000379:methods; D005822:Genetic Vectors; D016086:Lentivirus / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*; D051381:Rats
chemical_list: D035683:MicroRNAs; D034741:RNA, Small Interfering