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Quantum dot‐mediated delivery of siRNA to inhibit sphingomyelinase activities in brain‐derived cells
Author(s) -
Getz Ted,
Qin Jingdong,
Medintz Igor L.,
Delehanty James B.,
Susumu Kimihiro,
Dawson Philip E.,
Dawson Glyn
Publication year - 2016
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.13841
Subject(s) - rna , luciferase , small interfering rna , sphingomyelin phosphodiesterase , cytosol , cell culture , biochemistry , messenger rna , chemistry , microbiology and biotechnology , biophysics , biology , sphingomyelin , membrane , transfection , enzyme , gene , genetics
The use of RNA i to suppress protein synthesis offers a potential way of reducing the level of enzymes or the synthesis of mutant toxic proteins but there are few tools currently available for their delivery. To address this problem, bioconjugated quantum dots ( QD s) containing a hydrophobic component ( N ‐palmitate) and a sequence VKIKK designed to traverse across cell membranes and visualize drug delivery were developed and tested on cell lines of brain origin. We used the Zn outer shell of the QD to bind HIS 6 in JB 577 (W•G•Dap(N‐Palmitoyl)•VKIKK•P 9 •G 2 •H 6 ) and by a gel‐shift assay showed that si RNA s would bind to the positively charged KIKK sequence. By comparing many peptides and QD coatings, we showed that the QD ‐ JB 577‐si RNA construct was taken up by cells of nervous system origin, distributed throughout the cytosol, and inhibited protein synthesis, implying that JB 577 was also promoting endosome egress. By attaching si RNA for luciferase in a cell line over‐expressing luciferase, we showed 70% inhibition of mRNA after 24–48 h. To show more specific effects, we synthesized si RNA for neutral ( NSM ase2), acid (lysosomal ASM ase) sphingomyelinase, and sphingosine kinase 1 ( SK 1), we demonstrated a dose‐dependent inhibition of activity. These data suggest that QD s are a useful si RNA delivery tool and QD ‐si RNA could be a potential theranostic for a variety of diseases.