Action and Reaction: The Biological Response to siRNA and Its Delivery Vehicles

Kanasty, Rosemary; Whitehead, Kathryn A.; Vegas, Arturo J.; Anderson, Daniel G.

doi:10.1038/mt.2011.294

Cited by 235 publications

(178 citation statements)

References 170 publications

(252 reference statements)

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“…Given the extensive data available that siRNAs can induce toll-like receptor (TLR)-mediated inflammatory responses in cells in vitro and in vivo 26 , we wished to determine the inflammatory profile of claudin-5 siRNA compared with both NT siRNA and a 2′OMe-modified claudin-5 siRNA. It has been shown that 2′OMe backbone modifications in even 2 residues of an siRNA can abrogate these effects and, in this regard, we designed an siRNA with 2 modifications in the sense strand of the siRNA 27 .…”

Section: Efficacy Of Systemic Administration Of Claudin-5 Sirnamentioning

confidence: 99%

Targeted suppression of claudin-5 decreases cerebral oedema and improves cognitive outcome following traumatic brain injury

et al. 2012

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Traumatic brain injury is the leading cause of death in children and young adults globally. malignant cerebral oedema has a major role in the pathophysiology that evolves after severe traumatic brain injury. Added to this is the significant morbidity and mortality from cerebral oedema associated with acute stroke, hypoxic ischemic coma, neurological cancers and brain infection. Therapeutic strategies to prevent cerebral oedema are limited and, if brain swelling persists, the risks of permanent brain damage or mortality are greatly exacerbated. Here we show that a temporary and size-selective modulation of the blood-brain barrier allows enhanced movement of water from the brain to the blood and significantly impacts on brain swelling. We also show cognitive improvement in mice with focal cerebral oedema following administration in these animals of short interfering RnA directed against claudin-5. These observations may have profound consequences for early intervention in cases of traumatic brain injury, or indeed any neurological condition where cerebral oedema is the hallmark pathology.

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Section: Efficacy Of Systemic Administration Of Claudin-5 Sirnamentioning

confidence: 99%

Targeted suppression of claudin-5 decreases cerebral oedema and improves cognitive outcome following traumatic brain injury

et al. 2012

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“…1A, 2A, 3B and 4B). [43][44][45][46][47] In addition, they might be relatively unstable under physiological conditions due to loose complexation. Serum triggers polyplex aggregation and may diminish the difference of performance of the two sets of polyplexes under physiologically relevant conditions.…”

Section: Transfection Silencing and Cytotoxicitymentioning

confidence: 99%

Mixing-sequence-dependent nucleic acid complexation and gene transfer efficiency by polyethylenimine

et al. 2015

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Polyplexes, complexed nucleic acids by cationic polymers, are the most common forms of nonviral gene delivery vectors. In contrast to a great deal of efforts in synthesizing novel cationic polymers and exploring their extracellular and intracellular delivery pathways, polyplex preparation methods of mixing nucleic acids and cationic polymers are often overlooked. In this study, the mixing sequence, that is adding nucleic acids to polymers or vice versa, was found to greatly affect complexation of both plasmid DNA and siRNA, polyplexes' size, and polyplexes' surface charge, which all collaboratively affected the transfection efficiency and cytotoxicity. Adding polyethylenimine (PEI), the most conventionally used standard in nonviral gene delivery, to plasmid DNA and siRNA resulted in larger polyplexes, higher gene expression and silencing, but higher cytotoxicity than polyplexes prepared in the reverse order. Based on the experimental results, the authors developed a model that gradual addition of cationic polymers (e.g., PEI) to nucleic acids (e.g., plasmid DNA and siRNA) incorporates more copies of nucleic acids in larger polyplexes in a smaller number, results in higher gene expression and silencing levels in transfected cells, and generates higher cytotoxicity by leaving more free polymers upon complete mixing than the other mixing sequence. The proposed model can be explored using a broad range of cationic polymers and nucleic acids, and provide insightful information about how to prepare polyplexed nonviral vectors for efficient and safe gene delivery.

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“…One limitation of PEI as a transfection agent has been that both toxicity and delivery efficiency correlates with average molecular weight (MW) [23], and an average MW of 25kDa is generally considered the upper limit before the toxicity becomes problematic [11]. Several strategies have been devised to preserve the low toxicity of low-MW PEI but improve the delivery capability.…”

Section: Introductionmentioning

confidence: 99%

Elucidating the role of free polycations in gene knockdown by siRNA polyplexes

et al. 2016

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Future improvements of non-viral vectors for siRNA delivery require better understanding of intracellular processing and vector interactions with target cells. Here, we have compared the siRNA delivery properties of a lipid derivative of bPEI 1.8kDa (DOPE-PEI) with branched polyethyleneimine (bPEI) with average molecular weights of 1.8kDa (bPEI 1.8kDa) and 25 kDa (bPEI 25kDa). We find mechanistic differences between the DOPE-PEI conjugate and bPEI regarding siRNA condensation and intracellular processing. bPEI 1.8kDa and bPEI 25kDa have similar properties with respect to condensation capability, but are very different regarding siRNA decondensation, cellular internalization and induction of reporter gene knockdown. Lipid conjugation of bPEI 1.8kDa improves the siRNA delivery properties, but with markedly different 2 formulation requirements and mechanisms of action compared to conventional PEIs. Interestingly, strong knockdown using bPEI 25kDa is dependent on the presence of a free vector fraction which does not increase siRNA uptake. Finally, we have investigated the effect on lysosomal pH induced by these vectors to elucidate the differences in the proton sponge effect between lipid conjugated PEI and conventional PEI: Neither DOPE-PEI nor bPEI 25kDa affected lysosomal pH as a function of time, underlining that the possible proton sponge effect is not associated with changes in lysosomal pH.

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Action and Reaction: The Biological Response to siRNA and Its Delivery Vehicles

Cited by 235 publications

References 170 publications

Targeted suppression of claudin-5 decreases cerebral oedema and improves cognitive outcome following traumatic brain injury

Targeted suppression of claudin-5 decreases cerebral oedema and improves cognitive outcome following traumatic brain injury

Mixing-sequence-dependent nucleic acid complexation and gene transfer efficiency by polyethylenimine

Elucidating the role of free polycations in gene knockdown by siRNA polyplexes

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