Multifunctional REDV-G-TAT-G-NLS-Cys peptide sequence conjugated gene carriers to enhance gene transfection efficiency in endothelial cells

New insights for the development of efficient DNA vaccines

Despite the great potential of DNA vaccines for a broad range of applications, ranging from prevention of infections, over treatment of autoimmune and allergic diseases to cancer immunotherapies, the implementation of such therapies for clinical treatment is far behind the expectations up to now. The main reason is the poor immunogenicity of DNA vaccines in humans. Consequently, the improvement of the performance of DNA vaccines in vivo is required. This mini-review provides an overview of the current state of DNA vaccines and the various strategies to enhance the immunogenic potential of DNA vaccines, including (i) the optimization of the DNA construct itself regarding size, nuclear transfer and transcriptional regulation; (ii) the use of appropriate adjuvants; and (iii) improved delivery, for example, by careful choice of the administration route, physical methods such as electroporation and nanomaterials that may allow cell type-specific targeting. Moreover, combining nanoformulated DNA vaccines with other immunotherapies and prime-boost strategies may help to enhance success of treatment.

Peptide functionalized biomimetic gene complexes enhance specificity for vascular endothelial regeneration

Gene delivery presents great potential in endothelium regeneration and prevention of vascular diseases, but its outcome is inevitably limited by high shear stress and instable microenvironment. Highly efficient nanosystems may alleviate the problem with strong dual-specificity for diseased site and targeted cells. Hence, biomimetic coatings incorporating EC-targeting peptides were constructed by platelets and endothelial cells (ECs) for surface modification. A series of biomimetic gene complexes were fabricated by the biomimetic coatings to deliver pcDNA3.1-VEGF165 plasmid (pVEGF) for rapid recovery of endothelium. The gene complexes possessed good biocompatibility with macrophages, stability with serum and showed no evident cytotoxicity for ECs even at very high concentrations. Furthermore, the peptide modified gene complexes achieved selective internalization in ECs and significant accumulation in endothelium-injured site, especially the REDV-modified and EC-derived gene complexes. They substantially enhanced VEGF expression at mRNA and protein levels, thereby enabling a wound to heal completely within 24 h according to wound healing assay. In an artery endothelium-injured mouse model, the REDV-modified and EC-derived gene complexes presented efficient re-endothelialization with the help of enhanced specificity. The biomimetic gene complexes offer an efficient dual-targeting strategy for rapid recovery of endothelium, and hold potential in vascular tissue regeneration.

Amphiphilic multi-targeting copolymer micelles efficiently deliver pZNF580 to promote endothelial cell proliferation and migration

Cationic copolymers are widely used in gene delivery as a non-viral gene vector, but their applications are limited by low transfection efficiency and high cytotoxicity. In order to enhance the transfection efficiency of copolymer micelles to endothelial cells (HUVECs) and reduce their cytotoxicity, this study synthesized an amphipathic multi-targeted copolymer micelle delivery system PCLMD-PPEGMA-NLS-TAT-REDV (TCMs). Gel test results showed that TCMs showed good pZNF580 binding ability and could effectively load the pZNF580 plasmid. The CCK-8 results show that when the concentration of TCMs is greater than 60 μg mL-1, it will affect cell viability and have low cytotoxicity. We found that the multi-targeted copolymer micelles can be effectively taken up by HUVECs in vitro. The transfection efficiency of TCMs@pZNF580 (w/wpZNF580 = 3) to HUVECs was comparable to that of the positive control group lip2000@pZNF580, and WB also showed the same trend. In addition, the TCMs@pZNF580 complex also significantly enhanced the proliferation and migration of HUVECs. The experimental results on blood vessel formation showed that TCMs@pZNF580 accelerated the vascularization of HUVECs. This experiment provided a new technology platform for targeted gene therapy, especially for endothelialization and vascularization. The research results have important reference value for the treatment of cardiovascular diseases.

Chitosan Hydrogel as Tissue Engineering Scaffolds for Vascular Regeneration Applications

Chitosan hydrogels have a wide range of applications in tissue engineering scaffolds, mainly due to the advantages of their chemical and physical properties. This review focuses on the application of chitosan hydrogels in tissue engineering scaffolds for vascular regeneration. We have mainly introduced these following aspects: advantages and progress of chitosan hydrogels in vascular regeneration hydrogels and the modification of chitosan hydrogels to improve the application in vascular regeneration. Finally, this paper discusses the prospects of chitosan hydrogels for vascular regeneration.

Application of Peptides in Construction of Nonviral Vectors for Gene Delivery

Gene therapy, which aims to cure diseases by knocking out, editing, correcting or compensating abnormal genes, provides new strategies for the treatment of tumors, genetic diseases and other diseases that are closely related to human gene abnormalities. In order to deliver genes efficiently to abnormal sites in vivo to achieve therapeutic effects, a variety of gene vectors have been designed. Among them, peptide-based vectors show superior advantages because of their ease of design, perfect biocompatibility and safety. Rationally designed peptides can carry nucleic acids into cells to perform therapeutic effects by overcoming a series of biological barriers including cellular uptake, endosomal escape, nuclear entrance and so on. Moreover, peptides can also be incorporated into other delivery systems as functional segments. In this review, we referred to the biological barriers for gene delivery in vivo and discussed several kinds of peptide-based nonviral gene vectors developed for overcoming these barriers. These vectors can deliver different types of genetic materials into targeted cells/tissues individually or in combination by having specific structure-function relationships. Based on the general review of peptide-based gene delivery systems, the current challenges and future perspectives in development of peptidic nonviral vectors for clinical applications were also put forward, with the aim of providing guidance towards the rational design and development of such systems.

Designed Peptide Assemblies for Efficient Gene Delivery

The safe and efficient delivery of nucleic acids including DNA, mRNA, siRNA, and miRNA into targeted cells is critical for gene therapy. Currently, viral gene vectors are very popular, but they have potential toxicity and insecurity. Therefore, the development of nonviral vectors has attracted considerable research attention. Peptide assemblies are superior candidates for being used as gene vectors by having good biocompatibility, versatile molecular design, excellent assembly capacity, ease of modification, and stimuli responsivity. The de novo designed peptides not only can induce efficient condensation of nucleic acids into compacted nanoparticles and protect them from enzymatic digestion but also can effectively overcome biological barriers and improve gene delivery efficiency through targeted delivery, enhanced cellular uptake, improved endolysosomal escape, and nuclear importation. By having these merits, peptidic gene vectors are developing fast, showing outstanding advantages compared to liposome and polymer vectors. This Perspective focuses on peptidic gene delivery systems by emphasizing the molecular design strategies for meeting the criteria of gene condensation, protection from nuclease degradation, cellular uptake, endolysosomal escape, and so on. The new arising research area of peptide-based artificial viruses for gene and ribonucleoprotein delivery has also been reviewed. The challenges and future perspectives are put forward, aiming to provide a conclusive guide for the development of peptidic delivery systems to achieve efficient gene therapy.

AIEgen-Peptide Bioprobes for the Imaging of Organelles

Organelles are important subsystems of cells. The damage and inactivation of organelles are closely related to the occurrence of diseases. Organelles’ functional activity can be observed by fluorescence molecular tools. Nowadays, a series of aggregation-induced emission (AIE) bioprobes with organelles-targeting ability have emerged, showing great potential in visualizing the interactions between probes and different organelles. Among them, AIE luminogen (AIEgen)-based peptide bioprobes have attracted more and more attention from researchers due to their good biocompatibility and photostability and abundant diversity. In this review, we summarize the progress of AIEgen-peptide bioprobes in targeting organelles, including the cell membrane, nucleus, mitochondria, lysosomes and endoplasmic reticulum, in recent years. The structural characteristics and biological applications of these bioprobes are discussed, and the development prospect of this field is forecasted. It is hoped that this review will provide guidance for the development of AIEgen-peptide bioprobes at the organelles level and provide a reference for related biomedical research.

Bovine serum albumin-based biomimetic gene complexes with specificity facilitate rapid re-endothelialization for anti-restenosis

Re-endothelialization is a critical problem to inhibit postoperative restenosis, and gene delivery exhibits great potential in rapid endothelialization. Unfortunately, the therapeutic effect is enormously limited by inefficient specificity, poor biocompatibility and in vivo stability owing largely to the complicated in vivo environment. Herein, we developed a series of platelet membrane (PM) cloaked gene complexes based on natural bovine serum albumin (BSA) and polyethyleneimine (PEI). The gene complexes aimed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. Based on BSA and PM coating, these gene complexes exhibited good biocompatibility, stability with serum and robust homing to endothelium-injured site inherited from platelets. Besides, they enhanced the expression of VEGF protein by their high internalization and nucleus accumulation efficiency, and also substantially promoted migration and proliferation of vascular endothelial cells. The biological properties were further optimized via altering PEI and PM content. Finally, rapid recovery of endothelium in a carotid artery injured mouse model (79% re-endothelialization compared with model group) was achieved through two weeks' treatment by the PM cloaked gene complexes. High level of expressed VEGF in vivo was also realized by the gene complexes. Moreover, neointimal hyperplasia (IH) was significantly inhibited by the gene complexes according to in vivo study. The results verified the great potential of the PM cloaked gene complexes in re-endothelialization for anti-restenosis. STATEMENT OF SIGNIFICANCE: Rapid re-endothelialization is a major challenge to inhibit postoperative restenosis. Herein, a series of biodegradable and biocompatible platelet membrane (PM) cloaked gene complexes were designed to accelerate re-endothelialization for anti-restenosis via pcDNA3.1-VEGF165 (VEGF) plasmid delivery. The PM cloaked gene complexes provided high VEGF expression in vascular endothelial cells (VECs), rapid migration and proliferation of VECs and robust homing to endothelium-injured site. In a carotid artery injured mouse model, PM cloaked gene complexes significantly promoted VEGF expression in vivo, accelerated re-endothelialization and inhibited neointimal hyperplasia due to their good biocompatibility and superior specificity. Overall, the optimized PM cloaked gene complexes overcomes multiple obstacles in gene delivery for re-endothelialization and can be a promising candidate for gene delivery and therapy of postoperative restenosis.

A self-assembling peptidic platform to boost the cellular uptake and nuclear delivery of oligonucleotides

The design of non-viral vectors that efficiently deliver genetic materials into cells, in particular to the nucleus, remains a major challenge in gene therapy and vaccine development. To tackle the...

Applications and developments of gene therapy drug delivery systems for genetic diseases

Genetic diseases seriously threaten human health and have always been one of the refractory conditions facing humanity. Currently, gene therapy drugs such as siRNA, shRNA, antisense oligonucleotide, CRISPR/Cas9 system, plasmid DNA and miRNA have shown great potential in biomedical applications. To avoid the degradation of gene therapy drugs in the body and effectively deliver them to target tissues, cells and organelles, the development of excellent drug delivery vehicles is of utmost importance. Viral vectors are the most widely used delivery vehicles for gene therapy in vivo and in vitro due to their high transfection efficiency and stable transgene expression. With the development of nanotechnology, novel nanocarriers are gradually replacing viral vectors, emerging superior performance. This review mainly illuminates the current widely used gene therapy drugs, summarizes the viral vectors and non-viral vectors that deliver gene therapy drugs, and sums up the application of gene therapy to treat genetic diseases. Additionally, the challenges and opportunities of the field are discussed from the perspective of developing an effective nano-delivery system.

Polyethylenimine-Modified Bombyx mori Silk Fibroin as a Delivery Carrier of the ING4-IL-24 Coexpression Plasmid

One of the major challenges for lung cancer gene therapy is to find a gene delivery vector with high efficiency and low toxicity. In this study, low-molecular-weight polyethyleneimine (PEI, 1.8 kDa) was grafted onto the side chains of Bombyx mori silk fibroin (BSF) to prepare cationized BSF (CBSF), which was used to package the plasmid DNA (pDNA) encoded by the inhibitor of growth 4 (ING4) and interleukin-24 (IL-24). FTIR and 1H-NMR spectra demonstrated that PEI was effectively coupled to the side chains of BSF by amino bonds. The results of the trinitrobenzene sulfonic acid method and zeta potential showed that the free amino group content on BSF increased from 125.1 ± 1.2 µmol/mL to 153.5 ± 2.2 µmol/mL, the isoelectric point increased from 3.68 to 8.82, and the zeta potential reversed from - 11.8 ± 0.1 mV to + 12.4 ± 0.3 mV after PEI grafting. Positively charged CBSF could package pDNA to form spherical CBSF/pDNA complexes. In vitro, human lung adenocarcinoma A549 cells and human embryonic lung fibroblast WI-38 cells were transfected with CBSF/pDNA complexes. Confocal laser scanning microscopy analysis and flow cytometry tests showed that CBSF/pDNA complexes can effectively transfect A549 cells, and the transfection efficiency was higher than that of 25 kDa PEI/pDNA complexes. CCK-8 assay results showed that CBSF/pDNA complexes significantly inhibited the proliferation of A549 cells but had no significant effect on WI-38 cells and exhibited lower cytotoxicity to WI-38 cells than 25 kDa PEI. Therefore, a gene delivery system, constructed with the low-molecular-weight PEI-modified silk fibroin protein and the ING4-IL-24 double gene coexpression plasmid has potential applications in gene therapy for lung cancer.

A two-pronged approach to regulate the behaviors of ECs and SMCs by the dual targeting-nanoparticles

Inhibiting vascular restenosis remains a tricky challenge for the postoperative development of cardiovascular interventional therapy. The ideal approaches should activate endothelial cells (ECs) and restrain smooth muscle cells (SMCs), however, they are commonly contradictory. Herein, a strategy was developed for synchronizing ECs promotion and SMCs inhibition by codelivery DNA and siRNA for combination therapy. Thus, an easy and efficient strategy integrated dual-superiorities of precise targeting and dual therapeutic genes to precisely regulate the behaviors of ECs and SMCs. The ECs-targeting REDV peptide and SMCs-targeting VAPG peptide grafted anionic polymers were used to surface-functionalize the delivery nanoplatforms for vascular endothelial growth factor (VEGF) plasmids and ERK2 siRNA delivery, respectively. The dual targeting-nanoparticles were prepared by physical mixing method, and their outstanding advantages were confirmed by the co-culture experiments. In comparison with single targeting-nanoparticles and dual non-targeting-nanoparticles, the dual targeting-nanoparticles simultaneously enhanced ECs proliferation/migration and restrained SMCs proliferation/migration. Moreover, the dual targeting-nanoparticles group manifested the highest VEGF expression in ECs and the lowest ERK2 expression in SMCs. In summary, the two-pronged strategy with dual targeting-nanoparticles provides a valuable cornerstone for synchronizing ECs promotion and SMCs inhibition.

Recent advances in peptide-targeted micelleplexes: Current developments and future perspectives

The decoding of the human genome revolutionized the understanding of how genetics influence the interplay between health and disease, in a multidisciplinary perspective. Thus, the development of exogenous nucleic acids-based therapies has increased to overcome hereditary or acquired genetic-associated diseases. Gene drug delivery using non-viral systems, for instance micelleplexes, have been recognized as promising options for gene-target therapies. Micelleplexes are core-shell structures, at a nanometric scale, designed using amphiphilic block copolymers. These can self-assemble in an aqueous medium, leading to the formation of a hydrophilic and positively charged corona - that can transport nucleic acids, - and a hydrophobic core - which can transport poor water-soluble drugs. However, the performance of these types of carriers usually is hindered by several in vivo barriers. Fortunately, due to a significant amount of research, strategies to overcome these shortcomings emerged. With a wide range of structural features, good stability against proteolytic degradation, affordable characteristic, easy synthesis, low immunogenicity, among other advantages, peptides have increasingly gained popularity as target ligands for non-viral carriers. Hence, this review addresses the use of peptides with micelleplexes illustrating, through the analysis of in vitro and in vivo studies, the potential and future perspectives of this combination.

Novel Cell Permeable Polymers of N-Substituted L-2,3-Diaminopropionic Acid (DAPEGs) and Cellular Consequences of Their Interactions with Nucleic Acids

The present study aimed to synthesize novel polycationic polymers composed of N-substituted L-2,3-diaminopropionic acid residues (DAPEGs) and investigate their cell permeability, cytotoxicity, and DNA-binding ability. The most efficient cell membrane-penetrating compounds (O2Oc-Dap(GO2)_n-O2Oc-NH₂, where n = 4, 6, and 8) showed dsDNA binding with a binding constant in the micromolar range (0.3, 3.4, and 0.19 µM, respectively) and were not cytotoxic to HB2 and MDA-MB-231 cells. Selected compounds used in the transfection of a GFP plasmid showed high transfection efficacy and minimal cytotoxicity. Their interaction with plasmid DNA and the increasing length of the main chain of tested compounds strongly influenced the organization and shape of the flower-like nanostructures formed, which were unique for 5/6-FAM-O2Oc-[Dap(GO2)]₈-O2Oc-NH₂ and typical for large proteins.

Unexpected Amplification of Synergistic Gene Expression to Boom Vascular Flow in Advantageous Dual-Gene Co-expression Plasmid Delivery Systems over Physically Mixed Strategy

Gene therapy exerts powerful potential in the treatment of various diseases, such as overexpressing pro-angiogenic gene to accelerate angiogenesis and restore vascular flow of ischemic tissue. Tremendous efforts have been invested in developing gene carriers for high transfection efficiency, while little research has been devoted to synergistically expressing functional proteins via optimizing therapeutic genes. Actually, the amplified gene expression is the ultimate goal of gene delivery. Dual-gene co-delivery and coordinate expression become a "breach" of strengthened gene expression. Herein, we explored the synergistic effects on gene expression and pro-angiogenesis by two typical dual-gene delivery strategies to determine which one is more efficient. The physical mixing method used ZNF₅₈₀ and VEGF₁₆₅ plasmids with a 1/1 weight ratio (p1:1), and the other strategy involved chemically inserting ZNF₅₈₀ and VEGF₁₆₅ genes into one plasmid as a dual-gene co-expression plasmid (pZNF-VEGF). p1:1 and pZNF-VEGF were loaded by REDV-TAT-NLS-H₁₂ carrier, a promising peptide carrier, to form corresponding dual-gene delivery systems. Both systems exhibited approximately similar size and zeta potential, guaranteeing almost the same cellular uptake. We comprehensively evaluated two delivery systems through gene expression at mRNA and protein levels and angiogenesis-related activities in vitro and in vivo. Interestingly, the pZNF-VEGF group showed a remarkably amplified synergistic effect in the expression of ZNF₅₈₀ and VEGF₁₆₅ genes in comparison with the p1:1 group. More importantly, the unexpected amplified synergistic effect of dual-gene co-expression plasmid was further verified for proliferation, migration, and angiogenesis in vitro and in vivo. Accordingly, we believed that the co-delivery of dual genes via constructing co-expression plasmids offers a better option for gene therapy, which can more effectively enhance the synergistic expression of target genes than the physical mixing method.

From single to a dual-gene delivery nanosystem: coordinated expression matters for boosting the neovascularization in vivo

A dual-gene delivery system with coordinated expression function boosted the neovascularization.