pH-Sensitive Nanocarrier-Mediated Codelivery of Simvastatin and Noggin siRNA for Synergistic Enhancement of Osteogenesis

Abstract

The inexpensive hypolipidemic drug simvastatin (SIM), which promotes bone regeneration by enhancing bone morphogenetic protein 2 (BMP-2) expression, has been regarded as an ideal alternative to BMP-2 therapy. However, SIM has low bioavailability and may induce the upregulation of the BMP-2-antagonistic noggin protein, which greatly limits the osteogenic effect. Here, a pH-sensitive copolymer, monomethoxy-poly(ethylene glycol)- b-branched polyethyleneimine- b-poly( N-( N', N'-diisopropylaminoethyl)- co-benzylamino)aspartamide (mPEG-bPEI-PAsp(DIP-BzA)) (PBP), was synthesized and self-assembled into a cationic micelle. SIM and siRNA targeting the noggin gene (N-siRNA) were loaded into the PAsp(DIP-BzA) core and the cationic bPEI interlayer of the micelle via hydrophobic and electrostatic interactions, respectively. The SIM-loaded micelle effectively delivered SIM into preosteoblast MC3T3-E1 cells and rapidly released it inside the acidic lysosome, resulting in the elevated expression of BMP-2. Meanwhile, the codelivered N-siRNA effectively suppressed the expression of noggin. Consequently, SIM and N-siRNA synergistically increased the BMP-2/noggin ratio and resulted in an obviously higher osteogenetic effect than did simvastatin or N-siRNA alone, both in vitro and in vivo.

Synergistic MicroRNA Therapy in Liver Fibrotic Rat Using MRI‐Visible Nanocarrier Targeting Hepatic Stellate Cells

“…At pH 7.4, the nanoplex of N/P 10 showed roughly spherical shape and fairly uniform size of about 155.0 ± 10.8 nm in diameter (Figure D), which was slightly smaller than that detected by DLS measurement. On the contrary, random polymeric aggregates were observed at pH 5.0 (Figure E), which had a particle size of 1088 ± 108.5 nm as detected by the DLS measurement (Table S3, Supporting Information), likely because the complete protonation of DIP caused a hydrophilic transition of the PAsp(DIP–BzA) block, which induced the disassembly of nanoplex . As shown in Figure S3 (Supporting Information), the fluorescent intensity of Cy3‐labeled miRNA increased via pH 5.0 preincubation as compared with pH 7.4, which indicated that Cy3‐labeled miRNA was released from T‐SCR/S nanoplex due to the disassembly of T‐SCR nanoplex at pH 5.0 lowering miRNA complexation ability of free VA–PEG–bPEI–PAsp(DIP–BzA) during endo‐lysosomal escape .…”

“…The VA‐terminated pH‐sensitive copolymer, VA–PEG–bPEI–PAsp(DIP–BzA) or T‐PBP, was synthesized according to our recent report ( Figure A; Figure S1, Supporting Information) and characterized by gel permeation chromatography (GPC) and 1 H NMR. GPC chromatograms showed a unimodal molecular weight distribution for all copolymers and an increase in the molecular weight of final copolymer compared with the prepolymer, suggesting that VA‐terminated PEG was conjugated to final copolymer (Figure S2 and Table S2, Supporting Information).…”

“…The fluorescence of Cy3‐SCR (red) and LysoTracker (green) overlapped to show yellow stains at 0.5 h after transfection, indicating the location of SCR inside lysosome. However, the fluorescence of the Cy3‐SCR was separated from that of lysosome at 2 h after transfection, indicating lysosome escape of miRNAs likely due to the proton sponge effect of PEI and DIP groups …”

“…Preparation of Nanoplexes : The non‐VA‐decorated copolymer PEG–bPEI–PAsp(DIP–BzA), abbreviated as PBP, was synthesized according to the recent report . The synthesis of VA‐terminated copolymer VA–PEG–bPEI–PAsp(DIP–BzA), abbreviated as T‐PBP, is described in Figure S1 in the Supporting Information.…”

Codelivery of CRISPR-Cas9 and chlorin e6 for spatially controlled tumor-specific gene editing with synergistic drug effects

“…Combined therapy involving codelivery of two or more drugs is a common tumor treatment strategy (19)(20)(21)(22), but codelivery of Cas9 with small-molecular drugs has not been investigated thoroughly. For controlled release of Cas9, one approach is to induce release using a combination of internal and external stimuli (23).…”