Caged siRNAs for Spatiotemporal Control of Gene Silencing

Abstract

Various strategies have been employed to achieve control over delivery of siRNA molecules to intended target cells. Photocaging is one specific class of modifications for silencing oligonucleotides that block their bioactivity until exposure to near-ultraviolet light. These caged RNAi effectors enable both spatial and temporal targeting of a dosed release of gene silencing agents by directed light exposure that photocleaves the cage moieties. Herein we compare the photochemical properties of cage compounds and strategies for their use, attached either randomly or site-specifically, to demonstrate various forms of gene expression regulation in vitro and in vivo. This light-controllable strategy has potential applications for precisely probing developing biological systems and eventually enabling targeted gene-silencing therapeutics.

Remote activation of biomolecules in deep tissues using near-infrared-to-UV upconversion nanotransducers

“…1H, and the Inset shows the UCNs were used to prove that caged siRNAs and caged plasmid DNA can be uncaged and activated using NIR-to-UV upconverted light. Various strategies have been undertaken for caging nucleic acids with light-sensitive compounds (22) and caging with 4,5-dimethoxy-2-nitroacetophenone (DMNPE) was found to be effective in caging plasmid DNA and siRNA (7,23). The probable site of attachment of DMNPE to the phosphate backbone of DNA was proposed by Haselton and coworkers (24) Detailed schematic on caging of these nucleic acids with the chemical DMNPE and their uncaging with upconverted UV light emitted from the UCNs is as illustrated in Fig.…”

Spatiotemporally Controlled Nanoliter‐Scale Reconfigurable Microfluidics

“…33 Spatiotemporal control can be exercised through operation of a device such as a microreactor or a microfluidic chip, or chemically by establishing known diffusion rates or employing chemical compounds that respond to specific stimuli. [34][35][36][37] Microreactors can be composed of a network of micrometer-sized (10-300 mm) channels that are etched into a solid substrate and employ electrokinetic pumping to move reagents. 34 By altering voltages in the different channels of the microreactor, scientists are able to direct the flow of reagents, and thus control when and how they interact.…”

“…Chemical spatiotemporal control was achieved by Silva and Mooney by regulating the diffusion rate of a hydrogel chemical compound and by Casey et al by using light-sensitive compounds. 36,37 Spatiotemporal control has been employed in a variety of areas, such as regulation of gene therapy, improving blood vessel growth (angiogenesis), studying embryonic development, and controlling cell attachment. 33,[36][37][38] Through the use of photosensitive compounds, Casey et al were able to spatiotemporally control the activity of small interfering RNA (siRNA).…”

“…36,37 Spatiotemporal control has been employed in a variety of areas, such as regulation of gene therapy, improving blood vessel growth (angiogenesis), studying embryonic development, and controlling cell attachment. 33,[36][37][38] Through the use of photosensitive compounds, Casey et al were able to spatiotemporally control the activity of small interfering RNA (siRNA). 37 SiRNA molecules are used to regulate the expression of genes through degradation or by halting translation of messenger RNA (mRNA).…”

“…33,[36][37][38] Through the use of photosensitive compounds, Casey et al were able to spatiotemporally control the activity of small interfering RNA (siRNA). 37 SiRNA molecules are used to regulate the expression of genes through degradation or by halting translation of messenger RNA (mRNA). 39 In order to maximize the therapeutic effect of the siRNA, it was covalently modified with photosensitive compounds, a process called "photocaging."…”