Overcoming endosomal barrier by amphotericin B-loaded dual pH-responsive PDMA-b-PDPA micelleplexes for siRNA delivery.
The endosomal barrier is a major bottleneck for the effective intracellular delivery of siRNA by nonviral nanocarriers. Here, we report a novel amphotericin B (AmB)-loaded, dual pH-responsive micelleplex platform for siRNA delivery. Micelles were self-assembled from poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diisopropylamino)ethyl methacrylate) (PDMA-b-PDPA) diblock copolymers. At pH 7.4, AmB was loaded into the hydrophobic PDPA core, and siRNA was complexed with a positively charged PDMA shell to form the micelleplexes. After cellular uptake, the PDMA-b-PDPA/siRNA micelleplexes dissociated in early endosomes to release AmB. Live cell imaging studies demonstrated that released AmB significantly increased the ability of siRNA to overcome the endosomal barrier. Transfection studies showed that AmB-loaded micelleplexes resulted in significant increase in luciferase (Luc) knockdown efficiency over the AmB-free control. The enhanced Luc knockdown efficiency was abolished by bafilomycin A1, a vacuolar ATPase inhibitor that inhibits the acidification of the endocytic organelles. These data support the central hypothesis that membrane poration by AmB and increased endosomal swelling and membrane tension by a "proton sponge" polymer provided a synergistic strategy to disrupt endosomes for improved intracellular delivery of siRNA.
Department of Pharmacology, Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA.
Haijun
H
Yu
Yonglong
Y
Zou
Yiguang
Y
Wang
Xiaonan
X
Huang
Gang
G
Huang
Baran D
BD
Sumer
David A
DA
Boothman
Jinming
J
Gao
D000666:Amphotericin B / Q000737:chemistry*; D001692:Biological Transport; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry*; D011992:Endosomes / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008156:Luciferases / Q000172:deficiency / Q000235:genetics; D008823:Micelles; D011109:Polymethacrylic Acids / Q000737:chemistry*; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D004337:Drug Carriers; D008823:Micelles; D011109:Polymethacrylic Acids; D034741:RNA, Small Interfering; C570790:poly(2-(dimethylamino)ethyl methacrylate)-block-poly(2-(diisopropylamino)ethyl methacrylate); D000666:Amphotericin B; D008156:Luciferases