Organ- and cell-specific delivery of mRNA via modular lipid nanoparticles (LNPs) is promising in treating various diseases, but targeted cargo delivery is still very challenging. Most previous work focuses on screening ionizable and helper lipids to address the above issues. Here, we report the multifacial role of PEGylated lipids in manipulating LNP-mediated delivery of mRNA to the liver. We employed the typical excipients in LNP products, including DLin-MC3-DMA, DPSC, and cholesterol. Five types of PEGylated lipids were selected, and their molar ratio was fixed at 1.5% with a constant PEG molecular weight of 2000 Da. The architecture of steric lipids dramatically affected the in vitro gene transfection, in vivo blood clearance, liver deposition, and targeting of specific cells, all of which were closely linked to the de-PEGylation rate. The fast de-PEGylation resulted in short blood circulation and high accumulation in the liver. However, the ultrafast de-PEGylation enabled the deposition of more LNPs in Kupffer cells other than hepatocytes. Surprisingly, simply changing the terminal groups of PEGylated lipids from methoxyl to carboxyl or amine could dramatically increase the liver delivery of LNPs, which might be associated with the accelerated de-PEGylation rate and enhanced LNP–cell interaction. The current work highlights the importance of manipulating steric lipids in promoting mRNA delivery, offering an alternative approach for formulating and optimizing mRNA LNPs.
Wenyu Li,Peng Zhang,Kun Zheng,Qiaoling Hu,Youxiang Wang
Extracellular stability to protect DNA against nucleases and stimulus-triggered intracellular DNA release are key factors in designing non-viral gene vectors. In this study, the diselenide-linked polycation mPEG–SeSe–PEI was developed as a new type of PEG-detachable gene vector for redox-responsive gene delivery. The corresponding stable analog mPEG–PEI and the disulfide-linked polycation mPEG–SS–PEI were synthesized as controls. The results showed that all the PEGylated polycations could condense DNA into tightly packed spherical nanoparticles about 80 nm in size, which showed excellent stability under physiological conditions. The results of zeta-potential measurements, stability tests and DNA release ability assay indicated that at a GSH concentration of 0.3 mM, the diselenide bonds were more easily cleaved than disulfide bonds, which facilitated dePEGylation and DNA release. Meanwhile, it was interestingly found that mPEG–SeSe–PEI/DNA polyplexes showed higher gene expression than mPEG–SS–PEI/DNA polyplexes in both HEK293T and HepG2 cells. Confocal laser scanning microscope (CLSM) images revealed that mPEG–SeSe–PEI/DNA polyplexes showed more efficient endosomal escape ability than mPEG–SS–PEI/DNA polyplexes. Based on these results, the diselenide bonds as a novel strategy are more suitable to address the challenging problem of extracellular stability and intracellular DNA release.
Yan Liang,Ping-Yu Wang,You-Jie Li,Ze-Yun Liu,Ran-Ran Wang,Guang-Bin Sun,Hong-Fang Sun,Shu-Yang Xie
Reduced drug uptake and elevated drug efflux are two major mechanisms in cancer multidrug resistance (MDR). In the present study, a new multistage O 2 -producing liposome with NAG/R8-dual-ligand and stimuli-responsive dePEGylation was developed to address the abovementioned issues simultaneously. The designed C-NAG-R8-PTXL/MnO 2 -lip could also achieve magnetic resonance imaging (MRI)-guided synergistic chemodynamic/chemotherapy (CDT/CT). In vitro and in vivo studies showed that C-NAG-R8-PTXL/MnO 2 -lip enhanced circulation time by PEG and targeted the tumor site. After tumor accumulation, endogenous l -cysteine was administered, and the PEG-attached disulfide bond was broken, resulting in the dissociation of PEG shells. The previously hidden positively charged R8 by different lengths of PEG chains was exposed and mediated efficient internalization. In addition, the oxygen (O 2 ) generated by C-NAG-R8-PTXL/MnO 2 -lip relieved the hypoxic environment within the tumor, thus reducing the efflux of chemotherapeutic drug. O 2 was able to burst liposomes and triggered the release of PTXL . The toxic hydroxyl radical (·OH), which was produced by H 2 O 2 and Mn 2+ , strengthened CDT/CT. C-NAG-R8-PTXL/MnO 2 -lip was also used as MRI contrast agent , which blazed the trail to rationally design theranostic agents for tumor imaging.
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