title: siRNA delivery to CNS cells using a membrane translocation peptide.
abstract: RNA interference (RNAi) is a sequence-specific gene silencing technique that has been applied to multiple pathological conditions. In this report, we describe the generation and in vitro characterization of an RNAi-based fluorescent probe for use as a therapeutic in the setting of ischemic stroke. Probe delivery to bEnd.3 brain endothelial cells and primary cortical neurons and astrocytes was promoted by incorporating small interfering RNA (siRNA) into complexes with fluorescently labeled myristoylated polyarginine peptides. The resulting probe was partially protected from serum nuclease degradation and was efficiently internalized by cells as confirmed by flow cytometry and confocal microscopy. In addition, application of the siRNA probe directed against c-Src, a protein implicated in stroke pathology, led to statistically significant reduction of endogenous c-src mRNA levels in all cell types tested. Results demonstrate the proof-of-principle that functionalized peptide--siRNA probes can be used as potential tools for dual imaging and therapeutic applications.
authors.affiliation: Molecular Imaging Laboratory, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital,Harvard Medical School, Charlestown, Massachusetts 02129, USA.
authors.forename: Marytheresa A
authors.initials: MA
authors.lastname: Ifediba
authors.forename: Zdravka
authors.initials: Z
authors.lastname: Medarova
authors.forename: Shu-wing
authors.initials: SW
authors.lastname: Ng
authors.forename: Junzheng
authors.initials: J
authors.lastname: Yang
authors.forename: Anna
authors.initials: A
authors.lastname: Moore
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D001921:Brain / Q000166:cytology*; D002460:Cell Line; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism; D020868:Gene Silencing; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry*; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry; D014162:Transfection
chemical_list: D010455:Peptides; D034741:RNA, Small Interfering; C015462:polyarginine; D011505:Protein-Tyrosine Kinases