scholarly journals Hydrophobicity drives the systemic distribution of lipid-conjugated siRNAs via lipid transport pathways

2018 ◽  
Author(s):  
Maire F. Osborn ◽  
Andrew H. Coles ◽  
Annabelle Biscans ◽  
Reka A. Haraszti ◽  
Loic Roux ◽  
...  
Keyword(s):  
Sirna Delivery ◽  
Lipid Transport ◽  
Small Interfering Rnas ◽  
Transport Pathways ◽  
Efficient Delivery ◽  
Systemic Distribution ◽  
Lipoprotein Binding ◽  
The Impact ◽  
Plasma Half Life

AbstractEfficient delivery of therapeutic RNA is the fundamental obstacle preventing its clinical utility. Lipid conjugation improves plasma half-life, tissue accumulation, and cellular uptake of small interfering RNAs (siRNAs). However, the impact of conjugate structure and hydrophobicity on siRNA pharmacokinetics is unclear, impeding the design of clinically relevant lipid-siRNAs. Using a panel of biologically-occurring lipids, we show that lipid conjugation modulates siRNA hydrophobicity and governs spontaneous partitioning into distinct plasma lipoprotein classes in vivo. Lipoprotein binding influences siRNA distribution by delaying renal excretion and promoting uptake into lipoprotein receptor-enriched tissues. Lipid-siRNAs elicit mRNA silencing without causing toxicity in a tissue-specific manner. Lipid-siRNA internalization occurs independently of lipoprotein endocytosis, and is mediated by siRNA phosphorothioate modifications. Although biomimetic lipoprotein nanoparticles have been considered for the enhancement of siRNA delivery, our findings suggest that hydrophobic modifications can be leveraged to incorporate therapeutic siRNA into endogenous lipid transport pathways without the requirement for synthetic formulation.

scholarly journals The chemical structure and phosphorothioate content of hydrophobically modified siRNAs impact extrahepatic distribution and efficacy

2020 ◽  
Vol 48 (14) ◽  
pp. 7665-7680
Author(s):  
Annabelle Biscans ◽  
Jillian Caiazzi ◽  
Sarah Davis ◽  
Nicholas McHugh ◽  
Jacquelyn Sousa ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Clinical Stage ◽  
Sirna Delivery ◽  
Fine Tuning ◽  
Endosomal Escape ◽  
Systematic Evaluation ◽  
Small Interfering Rnas ◽  
Tissue Accumulation ◽  
The Impact

Abstract Small interfering RNAs (siRNAs) have revolutionized the treatment of liver diseases. However, robust siRNA delivery to other tissues represents a major technological need. Conjugating lipids (e.g. docosanoic acid, DCA) to siRNA supports extrahepatic delivery, but tissue accumulation and gene silencing efficacy are lower than that achieved in liver by clinical-stage compounds. The chemical structure of conjugated siRNA may significantly impact invivo efficacy, particularly in tissues with lower compound accumulation. Here, we report the first systematic evaluation of the impact of siRNA scaffold—i.e. structure, phosphorothioate (PS) content, linker composition—on DCA-conjugated siRNA delivery and efficacy in vivo. We found that structural asymmetry (e.g. 5- or 2-nt overhang) has no impact on accumulation, but is a principal factor for enhancing activity in extrahepatic tissues. Similarly, linker chemistry (cleavable versus stable) altered activity, but not accumulation. In contrast, increasing PS content enhanced accumulation of asymmetric compounds, but negatively impacted efficacy. Our findings suggest that siRNA tissue accumulation does not fully define efficacy, and that the impact of siRNA chemical structure on activity is driven by intracellular re-distribution and endosomal escape. Fine-tuning siRNA chemical structure for optimal extrahepatic efficacy is a critical next step for the progression of therapeutic RNAi applications beyond liver.

scholarly journals Vehicles for Small Interfering RNA transfection: Exosomes versus Synthetic Nanocarriers

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Markus Duechler
Keyword(s):  
Small Rnas ◽  
Sirna Delivery ◽  
Target Cells ◽  
Messenger Rnas ◽  
Small Interfering Rnas ◽  
Rna Transfection ◽  
Efficient Delivery ◽  
Micro Rnas ◽  
Delivery Vehicles ◽  
Interfering Rna

AbstractTherapies based on RNA interference (RNAi) hold a great potential for targeted interference of the expression of specific genes. Small-interfering RNAs (siRNA) and micro-RNAs interrupt protein synthesis by inducing the degradation of messenger RNAs or by blocking their translation. RNAibased therapies can modulate the expression of otherwise undruggable target proteins. Full exploitation of RNAi for medical purposes depends on efficient and safe methods for delivery of small RNAs to the target cells. Tremendous effort has gone into the development of synthetic carriers to meet all requirements for efficient delivery of nucleic acids into particular tissues. Recently, exosomes unveiled their function as a natural communication system which can be utilized for the transport of small RNAs into target cells. In this review, the capabilities of exosomes as delivery vehicles for small RNAs are compared to synthetic carrier systems. The step by step requirements for efficient transfection are considered: production of the vehicle, RNA loading, protection against degradation, lack of immunogenicity, targeting possibilities, cellular uptake, cytotoxicity, RNA release into the cytoplasm and gene silencing efficiency. An exosomebased siRNA delivery system shows many advantages over conventional transfection agents, however, some crucial issues need further optimization before broad clinical application can be realized.

scholarly journals Hydrophobicity drives the systemic distribution of lipid-conjugated siRNAs via lipid transport pathways

2018 ◽  
Vol 47 (3) ◽  
pp. 1070-1081 ◽  
Author(s):  
Maire F Osborn ◽  
Andrew H Coles ◽  
Annabelle Biscans ◽  
Reka A Haraszti ◽  
Loic Roux ◽  
...  
Keyword(s):  
Lipid Transport ◽  
Transport Pathways ◽  
Systemic Distribution

scholarly journals Non-Viral Delivery and Therapeutic Application of Small Interfering RNAs

Acta Naturae ◽  
2013 ◽  
Vol 5 (3) ◽  
pp. 35-53 ◽  
Author(s):  
N. A. Nikitenko ◽  
V. S. Prassolov
Keyword(s):  
Rna Interference ◽  
Gene Expression Regulation ◽  
Sirna Delivery ◽  
Target Cells ◽  
Powerful Method ◽  
Small Interfering Rnas ◽  
Therapeutic Application ◽  
Rnai Technology ◽  
In Vivo Degradation

RNA interference (RNAi) is a powerful method used for gene expression regulation. The increasing knowledge about the molecular mechanism of this phenomenon creates new avenues for the application of the RNAi technology in the treatment of various human diseases. However, delivery of RNA interference mediators, small interfering RNAs (siRNAs), to target cells is a major hurdle. Effective and safe pharmacological use of siRNAs requires carriers that can deliver siRNA to its target site and the development of methods for protection of these fragile molecules from in vivo degradation. This review summarizes various strategies for siRNA delivery, including chemical modification and non-viral approaches, such as the polymer-based, peptide-based, lipid-based techniques, and inorganic nanosystems. The advantages, disadvantages, and prospects for the therapeutic application of these methods are also examined in this paper.

scholarly journals Interorganelle lipid flux revealed by enzymatic mass tagging in vivo

2021 ◽  
Author(s):  
Arun T John Peter ◽  
Matthias Peter ◽  
Benoit Kornmann
Keyword(s):  
Living Cells ◽  
Lipid Transport ◽  
Proper Function ◽  
Transport Activity ◽  
Transport Pathways ◽  
Lipid Trafficking ◽  
Lipid Exchange ◽  
Obvious Reason ◽  
Cellular Organelles

The distinct activities of cellular organelles are dependent on the proper function of their membranes. Coordinated membrane biogenesis of the different organelles necessitates interorganelle transport of lipids from their site of synthesis to their destination membranes. Several proteins and trafficking pathways have been proposed to participate in lipid distribution, but despite the basic importance of this process, in vivo evidence linking the absence of putative transport pathways to specific transport defects remains scarce. An obvious reason for this scarcity is the near absence of in vivo lipid trafficking assays. Here we introduce a versatile method named METALIC (Mass tagging-Enabled TrAcking of Lipids In Cells) to track interorganelle lipid flux inside living cells. In this strategy, two enzymes, one directed to a "donor" and the other to an "acceptor" organelle, add two distinct mass tags to lipids. Mass spectrometry-based detection of lipids bearing the two mass tags is then used as a proxy for lipid exchange between the two organelles. By applying this approach to ER and mitochondria, we show that the ERMES and Vps13-Mcp1 complexes have lipid transport activity in vivo, and unravel their relative contributions to ER-mitochondria lipid exchange.

Abstract 289: Non-viral Rna Delivery To The Endothelium

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
daniel anderson
Keyword(s):  
Endothelial Cells ◽  
Vascular Dysfunction ◽  
High Specificity ◽  
Cell Types ◽  
Small Interfering Rnas ◽  
Efficient Delivery ◽  
Tumor Growth And Metastasis ◽  
Reduce Gene Expression

Dysfunctional vasculature contributes to more disease than any other tissue in the body1. Small interfering RNAs (siRNAs) have the potential to help elucidate the role of endothelial cells in vivo by durably silencing multiple genes simultaneously, but this requires efficient delivery, which has remained challenging in cell types besides hepatocytes. We have developed nanoparticles that deliver siRNA to endothelial cells with high specificity, thereby facilitating the silencing of multiple endothelial cell genes in vivo. These particles do not significantly reduce gene expression in hepatocytes or immune cells even at doses forty times greater than those required for endothelial gene silencing. Optimized formulations achieved the most durable non-liver silencing reported to date, and delivered siRNAs that modified endothelial function in mouse models of vascular permeability, emphysema, primary tumor growth, and metastasis. We believe the nanomaterial described here may improve the ability to study endothelial gene function in vivo, and be used to treat diseases caused by vascular dysfunction.

scholarly journals RNA interference and the use of small interfering RNA to study gene function in mammalian systems

2004 ◽  
Vol 33 (3) ◽  
pp. 545-557 ◽  
Author(s):  
I Bantounas ◽  
L A Phylactou ◽  
J B Uney
Keyword(s):  
Rna Interference ◽  
Gene Function ◽  
Viral Vector ◽  
Sirna Delivery ◽  
Interferon Response ◽  
Rnai Pathway ◽  
Small Interfering Rnas ◽  
Rnai Technology

In the past 2 years, extraordinary developments in RNA interference (RNAi)-based methodologies have seen small interfering RNAs (siRNA) become the method of choice for researchers wishing to target specific genes for silencing. In this review, an historic overview of the biochemistry of the RNAi pathway is described together with the latest advances in the RNAi field. Particular emphasis is given to strategies by which siRNAs are used to study mammalian gene function. In this regard, the use of plasmid-based and viral vector-based systems to mediate long-term RNAi in vitro and in vivo are described. However, recent work has shown that non-specific silencing effects and activation of the interferon response may occur following the use of some siRNA and delivery vector combinations. Future goals must therefore be to understand the mechanisms by which siRNA delivery leads to unwanted gene silencing effects in cells and, in this way, RNAi technology can reach its tremendous potential as a scientific tool and ultimately be used for therapeutic purposes.

scholarly journals Formulation Strategies, Characterization, and In Vitro Evaluation of Lecithin-Based Nanoparticles for siRNA Delivery

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sebastián Ezequiel Pérez ◽  
Yamila Gándola ◽  
Adriana Mónica Carlucci ◽  
Lorena González ◽  
Daniel Turyn ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Sirna Delivery ◽  
Physicochemical Characterization ◽  
Human Breast ◽  
Efficient Delivery ◽  
Interfering Rna ◽  
Mcf 7

The aim of the present work was to take advantage of lecithin’s biocompatibility along with its physicochemical properties for the preparation of lecithin-based nanocarriers for small interfering RNA (siRNA) delivery. Water lecithin dispersions were prepared in different conditions, loaded with siRNA at different N/P ratios, and evaluated for loading capacity. The most appropriate ones were then assayed for cytotoxicity and characterized in terms of particle size distribution, zeta potential, and morphology. Results demonstrated that formulations prepared at pH 5.0 and 7.0 were able to load siRNA at broad N/P ratios, and cellular uptake assays showed an efficient delivery of oligos in MCF-7 human breast cancer cells; fluorescent-labeled dsRNA mainly located next to its target, near the nucleus of the cells. No signs of toxicity were observed for broad compositions of lecithin. The physicochemical characterization of the siRNA-loaded dispersions exhibited particles of nanometric sizes and pH-dependant shapes, which make them suitable for ex vivo and in vivo further evaluation.

scholarly journals Tyrosine-Modification of Polypropylenimine (PPI) and Polyethylenimine (PEI) Strongly Improves Efficacy of siRNA-Mediated Gene Knockdown

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1809 ◽  
Author(s):  
Sandra Noske ◽  
Michael Karimov ◽  
Achim Aigner ◽  
Alexander Ewe
Keyword(s):  
Sirna Delivery ◽  
Nucleic Acid Delivery ◽  
Cationic Polymers ◽  
Small Interfering Rnas ◽  
Polymeric Systems ◽  
Rna Molecules ◽  
First Time ◽  
Tyrosine Modification

The delivery of small interfering RNAs (siRNA) is an efficient method for gene silencing through the induction of RNA interference (RNAi). It critically relies, however, on efficient vehicles for siRNA formulation, for transfection in vitro as well as for their potential use in vivo. While polyethylenimines (PEIs) are among the most studied cationic polymers for nucleic acid delivery including small RNA molecules, polypropylenimines (PPIs) have been explored to a lesser extent. Previous studies have shown the benefit of the modification of small PEIs by tyrosine grafting which are featured in this paper. Additionally, we have now extended this approach towards PPIs, presenting tyrosine-modified PPIs (named PPI-Y) for the first time. In this study, we describe the marked improvement of PPI upon its tyrosine modification, leading to enhanced siRNA complexation, complex stability, siRNA delivery, knockdown efficacy and biocompatibility. Results of PPI-Y/siRNA complexes are also compared with data based on tyrosine-modified linear or branched PEIs (LPxY or PxY). Taken together, this establishes tyrosine-modified PPIs or PEIs as particularly promising polymeric systems for siRNA formulation and delivery.

scholarly journals Lipid and Polymer-Based Nanoparticle siRNA Delivery Systems for Cancer Therapy

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2692 ◽  
Author(s):  
Francesco Mainini ◽  
Michael R. Eccles
Keyword(s):  
Cancer Therapy ◽  
Gene Silencing ◽  
Sirna Delivery ◽  
Cancer Therapeutics ◽  
Delivery Systems ◽  
Fine Tuning ◽  
Host Cells ◽  
Specific Cell ◽  
Small Interfering Rnas

RNA interference (RNAi) uses small interfering RNAs (siRNAs) to mediate gene-silencing in cells and represents an emerging strategy for cancer therapy. Successful RNAi-mediated gene silencing requires overcoming multiple physiological barriers to achieve efficient delivery of siRNAs into cells in vivo, including into tumor and/or host cells in the tumor micro-environment (TME). Consequently, lipid and polymer-based nanoparticle siRNA delivery systems have been developed to surmount these physiological barriers. In this article, we review the strategies that have been developed to facilitate siRNA survival in the circulatory system, siRNA movement from the blood into tissues and the TME, targeted siRNA delivery to the tumor or specific cell types, cellular uptake, and escape from endosomal degradation. We also discuss the use of various types of lipid and polymer-based carriers for cancer therapy, including a section on anti-tumor nanovaccines enhanced by siRNAs. Finally, we review current and recent clinical trials using NPs loaded with siRNAs for cancer therapy. The siRNA cancer therapeutics field is rapidly evolving, and it is conceivable that precision cancer therapy could, in the relatively near future, benefit from the combined use of cancer therapies, for example immune checkpoint blockade together with gene-targeting siRNAs, personalized for enhancing and fine-tuning a patient’s therapeutic response.

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