Molecular modeling and in vivo imaging can identify successful flexible triazine dendrimer-based siRNA delivery systems

JOURNAL OF CONTROLLED RELEASE

卷:153

Article; Proceedings Paper

Merkel, Olivia M.¹  Zheng, Mengyao¹  Mintzer, Meredith A.^2,3  Pavan, Giovanni M.⁴  Librizzi, Damiano⁵  Maly, Marek^4,6  Hoeffken, Helmut⁵  Danani, Andrea⁴  Simanek, Eric E.⁷  Kissel, Thomas¹ 

[1] Univ Marburg, Dept Pharmaceut & Biopharm, D-35032 Marburg, Germany

[2] Boston Univ, Dept Biomed Engn, Boston, MA 02215 USA

[3] Boston Univ, Dept Chem, Boston, MA 02215 USA

[4] Univ Appl Sci So Switzerland SUPSI, Lab Appl Math & Phys LaMFI, Ctr Galleria 2, CH-6928 Manno, Switzerland

[5] Univ Hosp Giessen & Marburg GmbH, Dept Nucl Med, D-35043 Marburg, Germany

[6] Univ JE Purkyne, Dept Phys, Usti Nad Labem 40096, Czech Republic

[7] Texas Christian Univ, Dept Chem, Ft Worth, TX 76129 USA

关键词: Triazine dendrimers;    RNA interference;    Molecular modeling;    Biodistribution;    Pharmacokinetics;    SPECT imaging;   

DOI  :  10.1016/j.jconrel.2011.02.016

来源: Elsevier

【 摘 要 】

This study aimed to identify suitable siRNA delivery systems based on flexible generation 2-4 triazine dendrimers by correlating physico-chemical and biological in vitro and in vivo properties of the complexes with thermodynamic parameters calculated using molecular modeling. The siRNA binding properties of the dendrimers and PEI 25 kDa were simulated, binding and stability were measured in SYBR Gold assays, and hydrodynamic diameters, zeta potentials, and cytotoxicity were quantified. These parameters were compared with cellular uptake of the complexes and their ability to mediate RNAi. Radiolabeled complexes were administered intravenously, and pharmacokinetic profiles and biodistribution of these polyplexes were assessed both invasively and non-invasively. All flexible triazine dendrimers formed thermodynamically more stable complexes than PEI. While PEI and the generation 4 dendrimer interacted more superficially with siRNA, generation 2 and 3 virtually coalesced with siRNA, forming a tightly intertwined structure. These dendriplexes were therefore more efficiently charge-neutralized than PEI complexes, reducing agglomeration. This behavior was confirmed by results of hydrodynamic diameters (72.0 nm-153.5 nm) and zeta potentials (4.9 mV-21.8 mV in 10 mM HEPES) of the dendriplexes in comparison to PEI complexes (312.8 nm-480.0 nm and 13.7 mV-17.4 mV in 10 mM HEPES). All dendrimers, even generation 3 and 4, were less toxic than PEI. All dendriplexes were efficiently endocytosed and showed significant and specific luciferase knockdown in HeLa/Luc cells. Scintillation counting confirmed that the generation 2 triazine complexes showed more than twofold prolonged circulation times as a result of their good thermodynamic stability. Conversely, generation 3 complexes dissociated in vivo, and generation 4 complexes were captured by the reticulo-endothelial system due to their increased surface charge. Molecular modeling proves very valuable for rationalizing experimental parameters based on the dendrimers' structural properties. Noninvasive molecular imaging predicted the in vivo fate of the complexes. Therefore, both techniques effectively promote the rapid development of safe and efficient siRNA formulations that are stable in vivo. (C) 2011 Elsevier B.V. All rights reserved.

【 授权许可】

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