Functional motor recovery from brain ischemic insult by carbon nanotube-mediated siRNA silencing

Abstract

Stroke is the second cause of death worldwide with ischemic stroke accounting for 80% of all stroke insults. Caspase-3 activation contributes to brain tissue loss and downstream biochemical events that lead to programmed cell death after traumatic brain injury. Alleviation of symptoms following ischemic neuronal injury can be potentially achieved by either genetic disruption or pharmacological inhibition of caspases. Here, we studied whether silencing of Caspase-3 using carbon nanotube-mediated in vivo RNA interference (RNAi) could offer a therapeutic opportunity against stroke. Effective delivery of siRNA directly to the CNS has been shown to normalize phenotypes in animal models of several neurological diseases. It is shown here that peri-lesional stereotactic administration of a Caspase-3 siRNA (siCas 3) delivered by functionalized carbon nanotubes (f-CNT) reduced neurodegeneration and promoted functional preservation before and after focal ischemic damage of the rodent motor cortex using an endothelin-1 induced stroke model. These observations illustrate the opportunity offered by carbon nanotube-mediated siRNA delivery and gene silencing of neuronal tissue applicable to a variety of different neuropathological conditions where intervention at well localized brain foci may offer therapeutic and functional benefits.nanomedicine | neurodegenerative | neuroprotection | neurosciences | gene therapy

Design of Cationic Multiwalled Carbon Nanotubes as Efficient siRNA Vectors for Lung Cancer Xenograft Eradication

“…Results obtained in this study demonstrated lack of toxicity of fMWNTs and their efficiency as cytosolic siRNA carriers in addition to the bioactivity of the delivered siRNA as demonstrated by efficient gene silencing in vivo superseding the efficiency of cationic liposomal vectors as previously reported in other studies using stroke and cancer disease models. 15,22 Interestingly, amino functional groups on the MWNTNH 3 + sidewalls can be further modified such as building dendritic structures as reported previously. 26,27 Engineering the degree and type of dendritic branching is expected to affect the degree of siRNA association and gene silencing efficiency.…”

“…Functional recovery was achieved to perilesional levels after stereotactic administration of the therapy in both pre and postlesioned animals. 15 Overall, although fCNTmediated gene silencing is at an early preclinical stage, recent studies have shown that f-CNT offer significant benefits in the area of gene therapy and more specifically gene silencing.…”

“…Advantages include efficient membrane translocation and in vivo stability. 15,16 fCNTs are able to deliver nucleic acids such as plasmid DNA, siRNA or aptamers intracellularly. In these studies, siRNA:fCNT complexation was achieved by (i) chemical conjugation of siRNA to the vector via cleavable disulfide linkage, (ii) adsorption of siRNA on the PEGphospholipid coat adsorbed onto the SWNTs, or (iii) by noncovalent complextion between the negatively charged siRNA and the cationic fCNTs.…”

Direct visualization of carbon nanotube degradation in primary cells by photothermal imaging

“…30 This type of nanotubes has been extensively used for different applications including therapy and imaging. [32][33][34] In particular, they have been explored as carriers of small interference RNA for gene silencing. 32,33 1 Their biodistribution and biodegradation have been also thoroughly assessed.…”

“…[32][33][34] In particular, they have been explored as carriers of small interference RNA for gene silencing. 32,33 1 Their biodistribution and biodegradation have been also thoroughly assessed. 5,35 In this context, we recently studied the kinetics of degradation of MWCNTs with different types of functionalization into long-term cultures of microglia using Raman spectroscopy.…”