bims-novged Biomed News
on Non-viral vectors for gene delivery
Issue of 2022‒02‒13
thirteen papers selected by
Benjamin Winkeljann
Ludwig-Maximilians University

  1. Biomacromolecules. 2022 Feb 09.
      Conjugated oligoelectrolyte COE-S6 contains an elongated conjugated core with three cationic charges at each termini of the internal core. As an analogue of bolaamphiphiles, these structural attributes lead to the formation of spherical nanoplexes with Dh = 205 ± 5.0 nm upon mixing with small interfering RNA (siRNA). COE-S6/siRNA nanocomplexes were shown to be protective toward RNase, stimulate endosome escape, and achieve transfection efficiencies comparable to those achieved with commercially available LIP3000. Moreover, COE-S6/siRNA nanocomplexes enabled efficient silencing of the K-ras gene in pancreatic cancer cells and significant inhibition of cancer tumor growth with negligible in vitro toxicities. More importantly, cell invasion and colony formation of the Panc-1 cells were significantly inhibited, and apoptosis of the pancreatic cancer cells was also promoted. We also note that COE-S6 is much less toxic relative to commercial lipid formulations, and it provides optical signatures that can enable subsequent mechanistic work without the need to label nucleotides. COE-S6-based nanoplexes are thus a promising candidate as nonviral vectors for gene delivery.
  2. J Control Release. 2022 Feb 04. pii: S0168-3659(22)00074-8. [Epub ahead of print]
      Nanoparticle drug carriers have been employed to achieve systemic delivery of nucleic acid therapeutics, including small interfering RNA (siRNA); however, non-specific distribution and immune-related events often cause undesired adverse effects. Thus, there is a need for a new technology capable of specifically delivering nucleic acid therapeutics to desired sites. We demonstrated the utility of iontophoresis (IP) using weak electric current (0.3-0.5 mA/cm2) as a local drug delivery technology. Our previous studies revealed that IP allows for transdermal permeation of nucleic acid therapeutics via induction of intercellular junction cleavage initiated by Ca2+ influx-mediated cellular signaling activation, and subsequent cytoplasmic delivery through a unique endocytosis process in both skin and other cells. Based on these findings, we hypothesized that IP may enable direct delivery of nucleic acid therapeutics to internal organs through non-blood circulatory pathways without the use of delivery carriers. Permeation of fluorescent-labeled nucleic acids administered via IP applied to the surface of the liver and pancreas was observed in both organs, but not with topical application. IP-mediated local delivery of siRNA into the liver and pancreas significantly suppressed target mRNA expression in each organ. Moreover, IP administration of therapeutic siRNA against the molecules responsible for liver steatosis and fibrosis significantly inhibited lipid accumulation and fibrotic hepatic damage in individual model mice. These findings suggest that IP may be a useful technology to directly deliver nucleic acid therapeutics to internal organs without use of drug delivery carriers via non-blood circulatory pathways.
    Keywords:  Drug delivery; Iontophoresis; Liver diseases; Nucleic acid therapeutics; siRNA
  3. Chem Phys Lipids. 2022 Feb 03. pii: S0009-3084(22)00006-8. [Epub ahead of print]243 105178
      Lipid nanoparticles (LNPs) mediated mRNA delivery has gained prominence due to the success of mRNA vaccines against Covid-19, without which it would not have been possible. However, there is little clinical validation of this technology for other mRNA-based therapeutic approaches. Systemic administration of LNPs predominantly targets the liver, but delivery to other organs remains a challenge. Local approaches remain a viable option for some disease indications, such as Cystic Fibrosis, where aerosolized delivery to airway epithelium is the preferred route of administration. With this in mind, novel cationic lipids (L1-L4) have been designed, synthesized and co-formulated with a proprietary ionizable lipid. These LNPs were further nebulized, along with baseline control DOTAP-based LNP (DOTAP+), and tested in vitro for mRNA integrity and encapsulation efficiency, as well as transfection efficiency and cytotoxicity in cell cultures. Improved biodegradability and potentially superior elimination profiles of L1-L4, in part due to physicochemical characteristics of putative metabolites, are thought to be advantageous for prospective therapeutic lung delivery applications using these lipids.
    Keywords:  Cationic lipids; DOTAP; LNP; Lipid nanoparticles; Lung; Nebulization; mRNA
  4. Biomed Mater. 2022 Feb 09.
      Programmed death ligand 1 (PD-L1) overexpressed on the surface of tumor cells is one of the reasons for tumor immune escape. Reducing PD-L1 expression has been proved to be an effective strategy to facilitate immune system activation and inhibit tumor progression. RNA interference (RNAi) is a promising technology for gene regulation in tumor therapy. In this study, we constructed a targeted siRNA delivery system NPs@apt to transfect PD-L1 siRNA into human non-small-cell lung carcinoma cell line (A549) for inhibiting tumor immune evasion. NPs@apt was prepared by compressing PD-L1 siRNA with cationic Lipofectamine 2000, fusing with erythrocyte membrane-derived nanovesicles, and further modifying with targeting AS1411 aptamer. The introduction of erythrocyte membrane endows the siRNA delivery system with lower cytotoxicity and the ability to escape from the phagocytosis of macrophages. The stability of NPs@apt and the protection to loaded siRNA were confirmed. In vitro studies after NPs@apt treatment demonstrated that PD-L1 siRNA was selectively delivered into A549 cells, and further resulted in PD-L1 gene knockdown, T cell activation and tumor cell growth inhibition. This study offers an alternative strategy for specific siRNA transfection for improving anti-tumor immunity.
    Keywords:  PD-L1; aptamer; erythrocyte membrane; immune escape; siRNA delivery
  5. Mater Sci Eng C Mater Biol Appl. 2022 Jan;pii: S0928-4931(21)00670-6. [Epub ahead of print]132 112530
      Interactions of nanoparticles (NPs) with lipid membranes have enormous biological implications especially for gene delivery applications. In this work, using all-atom steered- and molecular dynamics simulations, we investigated deformation of lipid membranes and pore closure during a NP penetration process. Three membrane bilayer models built from 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), dipalmitoylphosphatidylcholine (DPPC) and dilauroylphosphatidylcholine (DLPC), and a NP formed by 2 short interfering RNA (siRNA) and 6 polyethylenimine (PEI) molecules were used. Our results showed that different membrane lipids could lead to differences in pore formation (symmetric vs. asymmetric), and could undergo different levels of pore-mediated flip-flops during the closure. DLPC showed the largest number of flip-flops among the three lipid membranes. In addition, introduction of hydrophobic linoleic acid (LA) substitution onto the PEIs was found to facilitate pore formation, since the long LA tails could insert themselves into the hydrophobic region of the membrane where the lipid tails were less aligned. Compared with DPPC, POPC and DLPC membranes had less alignment of lipid tails in the bilayer, which promoted the insertion of LA tails and hence NP entry into the cell. Our observations provide valuable insight into the membrane deformations and pore dynamics during NP penetration and will be important for the design of NP carriers for effective gene delivery.
    Keywords:  Lipid flip-flop; Lipid membrane; Molecular dynamics; Nanoparticle; Polyethylenimine; Pore resealing; Short interfering RNA
  6. J Mater Chem B. 2022 Feb 10.
      Combined chemo-gene therapy has become a promising approach for enhanced anti-cancer treatment efficacy. However, effective co-delivery of therapeutic genes and drugs into target cells and tissues remains a major challenge. In this work, a GSH-responsive cationic fluoropolymer PSSF was designed as a co-delivery platform and synthesized by introducing a perfluorinated chain into a low-molecular weight PEI-based cationic polymer through a disulfide bond. PSSF exhibits good ability for drug and gene loading, as well as fast drug release in a GSH-rich environment. Gene transfection assay revealed that PSSF could deliver both model genes and the p53 gene into tumor cells smoothly with good protein expression, while maintaining good biocompatibility. It was also demonstrated that PSSF could simultaneously deliver the p53 gene and DOX into the HeLa cells efficiently and realize fast release of DOX. In vitro and in vivo anti-tumor assays both demonstrated that the co-delivery system could inhibit tumor growth more effectively than individual gene or drug therapy. Histopathological analysis of major organs indicated negligible systemic toxicity of such synergistic therapy systems. This rationally designed co-delivery vector provides an effective platform for the development of gene-drug synergistic therapy.
  7. J Control Release. 2022 Feb 03. pii: S0168-3659(22)00069-4. [Epub ahead of print]
      Although cancer immunotherapy has emerged as a novel cancer treatment modality, it still suffers from low therapeutic efficacy in clinics due to the presence of a low number of activated immune cells and immunosuppressive factors in the tumor microenvironment (TME). Immunomodulatory ribonucleic acids (RNAs) have been developed to improve the therapeutic efficacy of cancer immunotherapy through either regulating target cell functions [i.e., messenger RNA (mRNA) or small interfering RNA (siRNA)] or stimulating immune cells [i.e., toll-like receptors (TLRs) or cytosolic retinoic acid-inducible gene I (RIG-I) agonist]. However, RNA-based therapeutics face many biological barriers, including ineffective delivery to target cells, degradation by ribonucleases (RNases), and difficulties in passing through the cellular membranes. In this review, we discuss nanoparticle-based delivery strategies that can overcome these hurdles to enhance RNA-based immunomodulation in cancer immunotherapy. Various nanoparticle-based delivery has been reported to increase the delivery efficacy of RNAs, by improving cellular uptake, RNA stability, and accumulation at the desired sites (target cells and intracellular compartments). The nanoparticle-based delivery of multifaceted immunomodulatory RNAs could enhance cancer immunotherapy through the regulating functions of immune cells, tumor cells, and immunosuppressive factors as well as stimulating the immune cells by recognition of endosomal TLRs and cytosolic RIG-I. Nanotechnology-assisted RNA-based therapeutics are expected to offer tremendous potential and advances for treating cancer, viral infections, and other diseases.
    Keywords:  Cancer immunotherapy; Immunomodulatory RNA; Nanoparticles; RNA delivery system
  8. J Mater Chem B. 2022 Feb 10.
      Immune checkpoint blockade therapy against programmed death protein-1 and its ligand (PD-1/PD-L1) has been accepted as a promising approach to activate the immune system's anti-tumor response. Although small interfering RNA (siRNA) or antibodies can block the PD-1/PD-L1 pathway, the effect of this blockade is temporary and reversible. Here, we developed a nano-delivery system to achieve permanent disruption of the PD-L1 gene based on Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) gene editing technology. In this system, the CRISPR/Cas9 plasmid was delivered into melanoma B16F10 cells using a nucleobase-modified polyamidoamine (PAMAM) derivative namely AP-PAMAM, which was constructed through the modification with 2-amino-6-chloropurine. Meanwhile, the carrier could efficiently facilitate the endosomal escape of CRISPR/Cas9 plasmid and thereby inhibit PD-L1 expression in cancer cells. Moreover, the intravenous injection of AP-PAMAM/plasmid nanoparticles could recruit and activate CD8+ T cells at the tumor site, promoting the secretion of cytokines and the killing of tumor cells. Overall, this nano-delivery system for genome editing provided a promising strategy to block the PD-1/PD-L1 pathway and obtain effective tumor immunotherapy.
  9. Nanoscale. 2022 Feb 08.
      Gene therapy has been used in a variety of diseases and shows brilliant anticancer or cancer suppression effects. Gene therapy is gradually evolving as the most compelling frontier hotspot in the field of cancer therapy. The current vehicles used in gene therapy have poor safety and low delivery efficiency, and thus, it is urgent to develop novel delivery vehicles for gene therapy. Due to the excellent stability and biosafety of exosomes, their use as drug carriers for novel nucleic acid therapy is in full swing, revealing huge prospects for clinical application. Mesenchymal stem cells (MSCs) have a natural homing property and can spontaneously accumulate at injury sites, inflammation sites, and even tumour sites. This feature is attributed to a variety of tropism factors expressed on their surface; for example, CXC chemokine receptor type 4 (CXCR4) can specifically bind to the highly expressed stromal cell derived factor-1 (SDF-1) on the tumour surface, which is essential for accumulation of MSCs at the tumour site. The mesenchymal stem cells used in this study were genetically engineered to obtain exosomes with high CXCR4 expression as carriers for targeted gene-drug delivery, and then, the Survivin gene was loaded via electrotransformation to construct a brand-new gene-drug delivery system (CXCR4high Exo/si-Survivin). Finally, related in vivo and in vitro experiments were conducted. We observed that the new delivery system can efficiently aggregate at the tumour site and release siRNA into tumour cells, knocking down the Survivin gene in tumour cells in vivo and thereby inhibiting tumour growth. This new gene-drug delivery system has tremendous clinical transformation value and provides a new strategy for clinical treatment of tumours.
  10. Nat Nanotechnol. 2022 Feb 07.
      Nanoparticles are tested in mice and non-human primates before being selected for clinical trials. Yet the extent to which mRNA delivery, as well as the cellular response to mRNA drug delivery vehicles, is conserved across species in vivo is unknown. Using a species-independent DNA barcoding system, we have compared how 89 lipid nanoparticles deliver mRNA in mice with humanized livers, primatized livers and four controls: mice with 'murinized' livers as well as wild-type BL/6, Balb/C and NZB/BlNJ mice. We assessed whether functional delivery results in murine, non-human primate and human hepatocytes can be used to predict delivery in the other species in vivo. By analysing in vivo hepatocytes by RNA sequencing, we identified species-dependent responses to lipid nanoparticles, including mRNA translation and endocytosis. These data support an evidence-based approach to making small-animal preclinical nanoparticle studies more predictive, thereby accelerating the development of RNA therapies.
  11. Mater Horiz. 2022 Feb 08.
      The birth of RNAi technology has pioneered actionability at the molecular level. Compared to DNA, RNA is less stable and therefore requires more demanding delivery vehicles. With their flexible size, shape, structure, and accessible surface modification, non-viral vectors show great promise for application in RNA delivery. Different non-viral vectors have different ways of binding to RNA. Low immunotoxicity gives RNA significant advantages in tumor treatment. However, the delivery of RNA still has many limitations in vivo. This manuscript summarizes the size-targeting dependence of different organs, followed by a summary of nanovesicles currently in or undergoing clinical trials. It also reviews all RNA delivery systems involved in the current study, including natural, bionic, organic, and inorganic systems. It summarizes the advantages and disadvantages of different delivery methods, which will be helpful for future RNA vehicle design. It is hoped that this will be helpful for gene therapy of clinical tumors.
  12. Proc Natl Acad Sci U S A. 2022 Feb 15. pii: e2112696119. [Epub ahead of print]119(7):
      Lysine-specific demethylase 6A (KDM6A), also named UTX, is frequently mutated in bladder cancer (BCa). Although known as a tumor suppressor, KDM6A's therapeutic potential in the metastasis of BCa remains elusive. It also remains difficult to fulfill the effective up-regulation of KDM6A levels in bladder tumor tissues in situ to verify its potential in treating BCa metastasis. Here, we report a mucoadhesive messenger RNA (mRNA) nanoparticle (NP) strategy for the intravesical delivery of KDM6A-mRNA in mice bearing orthotopic Kdm6a-null BCa and show evidence of KDM6A's therapeutic potential in inhibiting the metastasis of BCa. Through this mucoadhesive mRNA NP strategy, the exposure of KDM6A-mRNA to the in situ BCa tumors can be greatly prolonged for effective expression, and the penetration can be also enhanced by adhering to the bladder for sustained delivery. This mRNA NP strategy is also demonstrated to be effective for combination cancer therapy with other clinically approved drugs (e.g., elemene), which could further enhance therapeutic outcomes. Our findings not only report intravesical delivery of mRNA via a mucoadhesive mRNA NP strategy but also provide the proof-of-concept for the usefulness of these mRNA NPs as tools in both mechanistic understanding and translational study of bladder-related diseases.
    Keywords:  KDM6A; bladder cancer; elemene; intravesical delivery; mRNA nanoparticles
  13. ACS Appl Mater Interfaces. 2022 Feb 09.
      Chemoimmunotherapy can synergistically enhance the therapeutic effects and decrease the side effects by a combined method. However, the effective targeted codelivery of various chemotherapeutic agents and siRNAs remains challenging. Although nanomedicine-based chemoimmunotherapy has shown great potential in cancer treatment in recent years, further effort is needed to simplify the nanocarrier designs and maintain their effective functions. Here, we report a simple but robust multifunctional liposomal nanocarrier that contains a pH-sensitive liposome (LP) shell and a dendritic core for tumor-targeted codelivery of programmed cell death ligand 1 (PD-L1) siRNA and doxorubicin (DOX) (siPD-L1@PM/DOX/LPs). siPD-L1@PM/DOX/LPs had a suitable particle size and zeta potential, excellent stability in serum, and pH-sensitive drug release in vitro. They exhibited significant cell proliferation inhibition compared to free DOX and DOX-loaded LPs and could escape endosomes, effectively release siRNA into the cytoplasm of MCF-7 cells, and significantly reduce the PD-L1 expression on tumor cells. In vivo imaging confirmed high accumulation of siPD-L1@PM/DOX/LPs at the tumor site. More importantly, compared with siPD-L1@PM/LPs or DOX alone, siPD-L1@PM/DOX/LPs were more effective in inhibiting tumor growth and activating cytotoxic T cells in vivo. In conclusion, this nanocarrier may hold promise as a codelivery nanoplatform to improve the treatment of various solid tumors.
    Keywords:  PD-L1 siRNA; chemoimmunotherapy; dendrimer; doxorubicin; pH-sensitive liposome