Time filter

Source Type

North Vancouver, Canada

Maier M.A.,Alnylam Pharmaceuticals | Jayaraman M.,Alnylam Pharmaceuticals | Matsuda S.,Alnylam Pharmaceuticals | Liu J.,Alnylam Pharmaceuticals | And 25 more authors.
Molecular Therapy | Year: 2013

In recent years, RNA interference (RNAi) therapeutics, most notably with lipid nanoparticle-based delivery systems, have advanced into human clinical trials. The results from these early clinical trials suggest that lipid nanoparticles (LNPs), and the novel ionizable lipids that comprise them, will be important materials in this emerging field of medicine. A persistent theme in the use of materials for biomedical applications has been the incorporation of biodegradability as a means to improve biocompatibility and/or to facilitate elimination. Therefore, the aim of this work was to further advance the LNP platform through the development of novel, next-generation lipids that combine the excellent potency of the most advanced lipids currently available with biodegradable functionality. As a representative example of this novel class of biodegradable lipids, the lipid evaluated in this work displays rapid elimination from plasma and tissues, substantially improved tolerability in preclinical studies, while maintaining in vivo potency on par with that of the most advanced lipids currently available. © The American Society of Gene & Cell Therapy. Source

Akinc A.,Alnylam Pharmaceuticals | Querbes W.,Alnylam Pharmaceuticals | De S.,Alnylam Pharmaceuticals | Qin J.,Alnylam Pharmaceuticals | And 21 more authors.
Molecular Therapy | Year: 2010

Lipid nanoparticles (LNPs) have proven to be highly efficient carriers of short-interfering RNAs (siRNAs) to hepatocytes in vivo; however, the precise mechanism by which this efficient delivery occurs has yet to be elucidated. We found that apolipoprotein E (apoE), which plays a major role in the clearance and hepatocellular uptake of physiological lipoproteins, also acts as an endogenous targeting ligand for ionizable LNPs (iLNPs), but not cationic LNPs (cLNPs). The role of apoE was investigated using both in vitro studies employing recombinant apoE and in vivo studies in wild-type and apoE-/- mice. Receptor dependence was explored in vitro and in vivo using low-density lipoprotein receptor (LDLR-/-)-deficient mice. As an alternative to endogenous apoE-based targeting, we developed a targeting approach using an exogenous ligand containing a multivalent N-acetylgalactosamine (GalNAc)-cluster, which binds with high affinity to the asialoglycoprotein receptor (ASGPR) expressed on hepatocytes. Both apoE-based endogenous and GalNAc-based exogenous targeting appear to be highly effective strategies for the delivery of iLNPs to liver. © The American Society of Gene & Cell Therapy. Source

Leung A.K.K.,University of British Columbia | Hafez I.M.,University of British Columbia | Baoukina S.,University of Calgary | Belliveau N.M.,Precision Nanosystems | And 6 more authors.
Journal of Physical Chemistry C | Year: 2012

Lipid nanoparticles (LNP) containing ionizable cationic lipids are the leading systems for enabling therapeutic applications of siRNA; however, the structure of these systems has not been defined. Here we examine the structure of LNP siRNA systems containing DLinKC2-DMA(an ionizable cationic lipid), phospholipid, cholesterol and a polyethylene glycol (PEG) lipid formed using a rapid microfluidic mixing process. Techniques employed include cryo-transmission electron microscopy, 31P NMR, membrane fusion assays, density measurements, and molecular modeling. The experimental results indicate that these LNP siRNA systems have an interior lipid core containing siRNA duplexes complexed to cationic lipid and that the interior core also contains phospholipid and cholesterol. Consistent with experimental observations, molecular modeling calculations indicate that the interior of LNP siRNA systems exhibits a periodic structure of aqueous compartments, where some compartments contain siRNA. It is concluded that LNP siRNA systems formulated by rapid mixing of an ethanol solution of lipid with an aqueous medium containing siRNA exhibit a nanostructured core. The results give insight into the mechanism whereby LNP siRNA systems are formed, providing an understanding of the high encapsulation efficiencies that can be achieved and information on methods of constructing more sophisticated LNP systems. © 2012 American Chemical Society. Source

Jayaraman M.,Alnylam Pharmaceuticals | Ansell S.M.,Alcana Technologies | Mui B.L.,Alcana Technologies | Tam Y.K.,Alcana Technologies | And 15 more authors.
Angewandte Chemie - International Edition | Year: 2012

Special (lipid) delivery: The role of the ionizable lipid pKa in the in?vivo delivery of siRNA by lipid nanoparticles has been studied with a large number of head group modifications to the lipids. A tight correlation between the lipid pKa?value and silencing of the mouse FVII gene (FVII ED50) was found, with an optimal pKa range of 6.2-6.5 (see graph). The most potent cationic lipid from this study has ED50 levels around 0.005?mg?kg?1 in mice and less than 0.03?mg?kg?1 in non-human primates. Source

Belliveau N.M.,Precision Nanosystems | Belliveau N.M.,University of British Columbia | Lin P.J.,University of British Columbia | Chen S.,University of British Columbia | And 9 more authors.
Molecular Therapy - Nucleic Acids | Year: 2012

Lipid nanoparticles (LNP) are the leading systems for in vivo delivery of small interfering RNA (siRNA) for therapeutic applications. Formulation of LNP siRNA systems requires rapid mixing of solutions containing cationic lipid with solutions containing siRNA. Current formulation procedures employ macroscopic mixing processes to produce systems 70-nm diameter or larger that have variable siRNA encapsulation efficiency, homogeneity, and reproducibility. Here, we show that microfluidic mixing techniques, which permit millisecond mixing at the nanoliter scale, can reproducibly generate limit size LNP siRNA systems 20 nm and larger with essentially complete encapsulation of siRNA over a wide range of conditions with polydispersity indexes as low as 0.02. Optimized LNP siRNA systems produced by microfluidic mixing achieved 50% target gene silencing in hepatocytes at a dose level of 10 μg/kg siRNA in mice. We anticipate that microfluidic mixing, a precisely controlled and readily scalable technique, will become the preferred method for formulation of LNP siRNA delivery systems. © 2012 American Society of Gene & Cell Therapy All rights reserved. Source

Discover hidden collaborations