DNA Delivery Research Articles

DNA-Based Nonviral Gene Therapy─Challenging but Promising.

Over the past decades, significant progress has been made in utilizing nucleic acids, including DNA and RNA molecules, for therapeutic purposes. For DNA molecules, although various DNA delivery systems have been established, viral vector systems are the go-to choice for large-scale commercial applications. However, viral systems have certain disadvantages such as immune response, limited payload capacity, insertional mutagenesis and pre-existing immunity. In contrast, nonviral systems are less immunogenic, not size limited, safer, and easier for manufacturing compared with viral systems. What's more, nonviral DNA vectors have demonstrated their capacity to mediate specific protein expression in vivo for diverse therapeutic objectives containing a wide range of diseases such as cancer, rare diseases, neurodegenerative diseases, and infectious diseases, yielding promising therapeutic outcomes. However, exogenous plasmid DNA is prone to degrade and has poor immunogenicity in vivo. Thus, various strategies have been developed: (i) designing novel plasmids with special structures, (ii) optimizing plasmid sequences for higher expression, and (iii) developing more efficient nonviral DNA delivery systems. Based on these strategies, many interesting clinical results have been reported. This Review discusses the development of DNA-based nonviral gene therapy, including novel plasmids, nonviral delivery systems, clinical advances, and prospects. These developments hold great potential for enhancing the efficacy and safety of nonviral gene therapy and expanding its applications in the treatment of various diseases.

Non-transgenic, PAMAM co-delivery DNA of interactive proteins NbCRVP and NbCalB endows Nicotiana benthamiana with a stronger antiviral effect to RNA viruses

BackgroundViral diseases continue to pose a major threat to the world’s commercial crops. The in-depth exploration and efficient utilization of resistance proteins have become crucial strategies for their control. However, current delivery methods for introducing foreign DNA suffer from host range limitations, low transformation efficiencies, tissue damage, or unavoidable DNA integration into the host genome. The nanocarriers provides a convenient channel for the DNA delivery and functional utilization of disease-resistant proteins.ResultsIn this research, we identified a cysteine-rich venom protein (NbCRVP) in Nicotiana benthamiana for the first time. Virus-induced gene silencing and transient overexpression clarified that NbCRVP could inhibit the infection of tobacco mosaic virus, potato virus Y, and cucumber mosaic virus, making it a broad-spectrum antiviral protein. Yeast two-hybrid assay, co-immunoprecipitation, and bimolecular fluorescence complementation revealed that calcium-dependent lipid-binding (CaLB domain) family protein (NbCalB) interacted with NbCRVP to assist NbCRVP playing a stronger antiviral effect. Here, we demonstrated for the first time the efficient co-delivery of DNA expressing NbCRVP and NbCalB into plants using poly(amidoamine) (PAMAM) nanocarriers, achieving stronger broad-spectrum antiviral effects.ConclusionsOur work presents a tool for species-independent transfer of two interacting protein DNA into plant cells in a specific ratio for enhanced antiviral effect without transgenic integration, which further demonstrated new strategies for nanocarrier-mediated DNA delivery of disease-resistant proteins.Graphical abstract

Furan-rich, biobased transfection agents as potential oligomeric candidates for intracellular plasmid DNA delivery.

Biobased, DNA delivery vectors have been synthesized with a core motif composed of 2,5-bishydroxymethylfuran (BHMF) readily available from an important biomass feedstock 5-hydroxymethyl furfural (HMF). To generate the product, BHMF was first converted to 2,5-furan bishydroxymethyl diacrylate (2,5-FDA), which was later conjugated with different types of secondary amines. Rich in tertiary nitrogen, these oligomeric FDA-amino esters demonstrated stable electrostatic interactions with negatively charged plasmid DNA in an aqueous environment. We evaluated synthetic routes toward these plasmid DNA-binding amino esters (pFASTs), identified their nanoscale features, and attempted to establish their structure-property relationship in the context of the DNA delivery. Our preliminary studies show that the pFASTs formed stable complexes with the plasmid DNA. Dynamic light scattering indicated that the DNA polyplexes of pFASTs have hydrodynamic diameters within the size range of 100-150 nm with a surface charge (ζ-potential) ranging from -10 to +33 mV, depending on pFAST type. These oligomeric amino esters rich in furan motif were also found to successfully transfect the GFP-expressing plasmid DNA intracellularly. Collectively, this study establishes a new route to produce DNA transfection agents from sustainable resources that can be used for transferring genetic materials for humans, veterinary, and agrochemical purposes.

Extracellular vesicles derived from oxidatively stressed stromal cells promote cancer progression

Like many diseases, cancer is influenced by oxidative stress. Increases in oxidative stress caused by factors such as environmental stressors and unhealthy diets can increase the risk of cancer and worsen cancer prognoses. However, oxidative stress does not always promote cancer. On the contrary, many chemotherapeutics induce the production of oxidative stress to kill cancer cells. The tumor microenvironment (TME) is another factor in cancer progression. Stromal cells, a part of the TME, communicate with cancer cells through extracellular vesicles (EVs) - the primary vehicles for the delivery of messengers, including proteins, metabolites, DNA, and RNA. We hypothesized that the TME mediates cancer’s response to oxidative stress by delivering EVs to cancer cells. In order to test this hypothesis, we treated breast cancer cells (HCC1806, SKBR3, MCF7, and MDA-MB-436) and lung cancer cells (A549 and PC9) with EVs derived from oxidatively stressed stromal cells and compared their expression of marker proteins of cell proliferation and epithelial to mesenchymal transition to cancer cells treated with EVs from control stromal cells and untreated cancer cells. We found that EVs extracted from oxidatively stressed adipocytes increased the cell proliferation of breast cancer cells. Additionally, we found that EVs extracted from lung fibroblasts promoted epithelialmesenchymal transition in lung cancer cells. These findings present a novel way that the TME influences cancer progression. The findings of this paper can inform future cancer prevention studies.

Diffusive delivery of plasmid DNA using zwitterionic carboxyalkyl poly(1-vinylimidazole) into skeletal muscle in vivo.

Zwitterionic carboxyalkyl poly(1-vinylimidazole) (CA-PVIm) polymers with imidazolium cations and carboxylate anions have been synthesized as a carrier for the in vivo delivery of plasmid DNA (pDNA) to skeletal muscle. From differential scanning calorimetry measurements, resulting CA-PVIm had intermediate water in hydration water as a biocompatible polymer. Notably, when the pDNA and resulting CA-PVIm were mixed, slight retarded bands of the pDNA were observed in agarose gel electrophoresis, suggesting the polyion complex (PIC) formation between the pDNA and CA-PVIm despite zwitterionic polymers. Resulting PICs maintained the higher-order structure of the pDNA. Using resulting pDNA PICs, the highest pDNA expression by intramuscular injection was achieved in the PIC with 7 mol% carboxymethylated PVIm, that is, CA1(7)-PVIm, observed in a widespread area by in vivo imaging system. These results suggest that the CA1(7)-PVIm/pDNA PIC is effective for the diffusive delivery of the pDNA into skeletal muscle for the treatment of serious muscle diseases.

Synthesis, characterization, and application of a biocompatible gene delivery nanocarrier constructed from gold nanostars and a chitosan–cyclodextrin–poly(ethylene imine) graft polymer

Synthesis of biocompatible nanocomposite with AuNS, CS and bPEI as a universal non-viral gene delivery nanocarrier for targeted delivery of therapeutic RNA and DNA to cells.

Methods for Assessing Plant Immune System Activation by Bacterial Extracellular Vesicles and Other Elicitors.

Bacterial extracellular vesicles (BEVs) are released from the surface of bacterial cells and contain a diverse molecular cargo. Studies conducted primarily with bacterial pathogens of mammals have shown that BEVs are involved in multiple processes such as cell-cell communication, the delivery of RNA, DNA, and proteins to target cells, protection from stresses, manipulation of host immunity, and other functions. Until a decade ago, the roles of BEVs in plant-bacteria interactions were barely investigated. However, recent studies have shown that BEVs of plant pathogens possess similar functions as their mammalian pathogen counterparts, and more research is now devoted to study their roles and interactions with plants. In the following methods chapter, we provide five well-validated assays to examine the interaction of BEVs with the plant immune system. These assays rely on different markers or immune outputs, which indicate the activation of plant immunity (defense marker gene expression, reactive oxygen species burst, seedling inhibition). Furthermore, we offer assays that directly evaluate the priming of the immune system following BEV challenge and the effectiveness of its response to subsequent local or systemic infection. Altogether, these assays provide a thorough examination to the interactions of BEVs and the plant immune system.

Lactosylated lipid calcium phosphate-based nanoparticles: A promising approach for efficient DNA delivery to hepatocytes.

For safe and effective gene therapy, the ability to deliver the therapeutic nucleic acid to the target sites is crucial. In this study, lactosylated lipid phosphate calcium nanoparticles (lac-LCP) were developed for targeted delivery of pDNA to the hepatocyte cells. The lac-LCP formulation contained lactose-modified cholesterol (CHL), a ligand that binds to the asialoglycoprotein receptor (ASGR) expressed on hepatocytes, and polyethyleneimine (PEI) in the core. Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) were used to monitor the chemical modification, and the physicochemical properties of NPs were studied using dynamic light scattering (DLS) and transmission electron microscopy (TEM). To evaluate transfection efficiency, cellular uptake and GFP expression were assessed using fluorescence microscopy and flow cytometry. The results revealed that lactose-targeted particles (lac-LCP) had a significant increase in cellular uptake by hepatocytes. The inclusion of a low molecular weight PEI (1.8 KDa) with a low PEI/pDNA ratio of 1 in the core of LCP, elicited high degrees of GFP protein expression (by 5 and 6-fold), which exhibited significantly higher efficiency than PEI 1.8 KDa and Lipofectamine. The successful functionalization and nuclear delivery of LCP NPs described here indicate its promise as an efficient delivery vector to hepatocyte nuclei.

Visualization of the Plasmid DNA Delivery System by Complementary Fluorescence Labeling of Arginine-Rich Peptides.

Cell-penetrating peptides, such as arginine-rich peptides, encapsulate nucleic acid drugs and deliver them to intracellular compartments. Comprehensive tracking of drug delivery systems (DDSs) provides information about the behavior of the drug as well as the fate of the drug carrier after drug release, which is crucial for minimizing side effects. In this study, we labeled peptides designed to carry plasmid DNA with two types of dyes, traditional dye fluorescein and aggregation-induced emission (AIE) dye tetraphenylethylene, and subsequently tracked the DDS through the complementary ON and OFF fluorescence behaviors of the dyes. Traditional fluorescent dyes are susceptible to aggregation-caused quenching during bioimaging, a problem that is mitigated by using AIE dyes. However, by using both of these contrasting fluorescent labels, we were able to clearly visualize the DDS at different stages of its deployment, from drug transport and delivery to carrier dissociation and migration, demonstrating the feasibility of accurate DDS visualization by complementary fluorescence labeling.

Nonviral Platform for Expression of Recombinant Protein in Insect Cells.

Nonviral transfection has been used to express various recombinant proteins, therapeutics, and virus-like particles(VLP) in mammalian and insect cells. Virus-free methods for protein expression require fewer steps for obtaining protein expression by eliminating virus amplification and measuring the infectivity of the virus. The nonviral method uses a nonlytic plasmid to transfect the gene of interest into the insect cells instead of using baculovirus, a lytic system. In this chapter, we describe one of the transfection methods, which uses polyethyleneimine (PEI) as a DNA delivery material into the insect cells to express the recombinant protein in both adherent and suspension cells.

Gene Silencing and Gene Delivery in Therapeutics: Insights Using Quantum Dots.

Hemophilia, cancer, diabetes, cardiovascular disease, mental health issues, immunological deficiencies, neuromuscular disease, blindness, and other ailments can all be treated with gene silencing and gene therapy, a growing discipline in medicine. It typically refers to a range of therapeutic techniques in which a patient's body's particular cells are given genetic material designed to correct and erase genetic flaws. The advancements in genetics and bioengineering have paved the way for the conceptualization of gene therapy through the manipulation of vectors, enabling the targeted transfer of extrachromosomal material to specific cells. One of the main focus areas of this methodology is the escalation of delivery vehicles (vectors), primarily plasmids or viruses; it still has difficulties because there is no good delivery mechanism that can precisely deliver stable small interfering Ribonucleic Acid (siRNA) or DNA to the target tissue location. As they are non-fluorescent, the siRNA or DNA delivery procedure is unable to be monitored by these carriers. In the context of quantum dots (QDs), the formation of QD-siRNA or QD/DNA complexes facilitated the real-time monitoring and precise localization of QDs during the silencing, delivery, and transfection processes. The unique dual-modality optical and fluorescent properties exhibited by quantum dots contribute to their utility as versatile imaging probes. The research studies discussed in this review article will provide a framework for designing efficient QD-based nanocarriers that can successfully carry therapeutic genetic tools into targeted cells. As a result of their findings, the researchers developed some unique QDs that successfully attached to the siRNA or DNA and carried it to the desired place. The use of these QD-based delivery devices could enhance the field of gene silencing and gene delivery.

A multiple shoot induction system for peptide-mediated gene delivery into plastids in Arabidopsis thaliana, Nicotiana benthamiana, and Fragaria×ananassa.

The plastid is a promising target for the production of valuable biomolecules via genetic engineering. We recently developed a plastid-specific gene delivery system for leaves or seedlings using KH-AtOEP34, a functional peptide composed of the polycationic DNA-binding peptide KH and the Arabidopsis thaliana plastid-targeting peptide OEP34. Here, we established a liquid culture system for inducing multiple shoots in the model plants A. thaliana and Nicotiana benthamiana and the crop plant strawberry (Fragaria×ananassa) and tested the use of these plant materials for peptide-mediated gene delivery to plastids. Our liquid culture system efficiently induced multiple shoots that were enriched in meristems. Using these meristems, we performed KH-AtOEP34-mediated gene delivery to plastids and tested the delivery and integration of a cassette composed of the spectinomycin resistance gene aadA, the GFP reporter gene, and sequences homologous to plastid DNA. Genotyping PCR revealed the integration of the cassette DNA into plastid DNA several days after delivery in all three plants. Confocal laser scanning microscopy and immunoblotting confirmed the presence of plasmid-derived GFP in the plastids of meristems, indicating that the plasmid DNA was successfully integrated into plastid DNA and that the cassette was expressed. These results suggest the meristems developed in our liquid culture system are applicable to peptide-mediated delivery of exogeneous DNA into plastids. The multiple shoots generated in our liquid novel culture system represent promising materials for in planta peptide-mediated plastid transformation in combination with spectinomycin selection.

The Protective Mechanism of TFAM on Mitochondrial DNA and its Role in Neurodegenerative Diseases.

Mitochondrial transcription factor A (TFAM) is a mitochondrial protein encoded by nuclear genes and transported from the cytoplasm to the mitochondria. TFAM is essential for the maintenance, expression, and delivery of mitochondrial DNA (mtDNA) and can regulate the replication and transcription of mtDNA. TFAM is associated with the formation of mtDNA nucleomimetic structures, mtDNA repair, and mtDNA stability. However, the mechanism by which TFAM protects mtDNA is still being studied. This review provides a summary of the protective mechanism of TFAM on mtDNA including the discrete regulatory effects of TFAM acetylation and phosphorylation on mtDNA, the regulation of Ca2+ levels by TFAM to activate transcription in mitochondria, and the increased binding of TFAM to mtDNA damage hot spots. This review also discusses the association between TFAM and some neurodegenerative diseases.

The Role of p53 in Nanoparticle-Based Therapy for Cancer.

p53 is arguably one of the most important tumor suppressor genes in humans. Due to the paramount importance of p53 in the onset of cell cycle arrest and apoptosis, the p53 gene is found either silenced or mutated in the vast majority of cancers. Furthermore, activated wild-type p53 exhibits a strong bystander effect, thereby activating apoptosis in surrounding cells without being physically present there. For these reasons, p53-targeted therapy that is designed to restore the function of wild-type p53 in cancer cells seems to be a very appealing therapeutic approach. Systemic delivery of p53-coding DNA or RNA using nanoparticles proved to be feasible both in vitro and in vivo. In fact, one p53-based therapeutic (gendicine) is currently approved for commercial use in China. However, the broad use of p53-based therapy in p53-inactivated cancers is severely restricted by its inadequate efficacy. This review highlights the current state-of-the-art in this area of biomedical research and also discusses novel approaches that may help overcome the shortcomings of p53-targeting nanomedicine.

Macrophage-hitchhiking interleukin-10 plasmid DNA delivery system modulates rheumatoid arthritis microenvironment via the re-polarization of macrophages

Rheumatoid arthritis (RA) is a common chronic inflammatory disease and the current treatments for RA are unsatisfactory due to the buffer barrier from the RA microenvironment. Interleukin-10 (IL-10) was found to be able to modulate rheumatoid arthritis microenvironment (RAM) by the metabolic reprogramming of macrophages. However, its clinical application has proven challenging mainly due to its short half-life, non-ideal targeting efficiency via systemic administration and poor tissue penetration. Taking advantage of the recruitment of macrophages, we constructed an innovative macrophage-hitchhiking IL-10 pDNA delivery system using the peptides bearing nuclear localization signal (NLS) and tuftsin-modified disulfide-crosslinked polymers (bPEI-SS-PEG-T) which was responsive to the intracellular glutathione concentration. Firstly, we formed NLS/DNA complexes via electrostatic interactions to enhance the nuclear entry efficiency. Then NLS/DNA complexes were combined with bPEI-SS-PEG-T to construct bPEI-SS-PEG-T/NLS/DNA NPs with sizes of 168.4 nm and zeta potentials of + 10.9 mV. As the bPEI-SS-PEG-T was biodegradable and the tuftsin peptides enhanced macrophage-mediated phagocytosis, the nanoparticles exhibited lower cytotoxicity and better cellular uptake in addition to higher nuclear entry efficiency, leading to better IL-10 plasmid transfection. In addition, these macrophage-hitchhiking nanoparticles could effectively accumulate at inflammatory sites of RA via intra-peritoneal injection due to the macrophage migration to the inflammatory joints and alleviate symptoms of inflammation in vivo by inducing the re-polarization of macrophages, which might be mediated by the inhibition of mammalian target of rapamycin (mTOR) and the induction of arginase-2 (Arg2). As a result, this macrophage-hitchhiking gene delivery system demonstrated excellent inflammation targeting ability, good nuclear entry ability, high IL-10 plasmid transfection efficiency and great therapeutic efficacy in vivo, which is promising for the treatment of rheumatoid arthritis. Besides, this delivery system also provides a novel strategy for the gene therapy and the gene delivery system design for rheumatoid arthritis and other similar inflammatory diseases from the perspective of the inflammatory microenvironment.

Second-Generation Polyamidoamine Dendrimer Conjugated with Oligopeptides Can Enhance Plasmid DNA Delivery In Vitro.

Poly(amidoamine) (PAMAM) dendrimers have attracted considerable attention in the field of gene therapy due to their flexibility in introducing different functional moieties and reduced toxicity at low generations. However, their transfection efficiency remains a limitation. Therefore, an essential approach for improving their transfection efficiency as gene carriers involves modifying the structure of PAMAM by conjugating functional groups around their surface. In this study, we successfully conjugated an RRHRH oligopeptide to the surface of PAMAM generation 2 (PAMAM G2) to create RRHRH-PAMAM G2. This construction aims to condense plasmid DNA (pDNA) and facilitate its penetration into cell membranes, leading to its promising potential for gene therapy. RRHRH-PAMAM G2/pDNA complexes were smaller than 100 nm and positively charged. Nano-polyplexes can enter the cell and show a high transfection efficiency after 24 h of transfection. The RRHRH-PAMAM G2 was non-toxic to HeLa, NIH3T3, A549, and MDA-MB-231 cell lines. These results strongly suggest that RRHRH-PAMAM G2 holds promise as a gene carrier for gene therapy owing to its biocompatibility and ability to deliver genes to the cell.

Nebulized inhalation of LPAE-HDAC10 inhibits acetylation-mediated ROS/NF-κB pathway for silicosis treatment

Silicosis is a serious silica-induced respiratory disease for which there is currently no effective treatment. Irreversible pulmonary fibrosis caused by persistent inflammation is the main feature of silicosis. As an underlying mechanism, acetylation regulated by histone deacetylases (HDACs) are believed to be closely associated with persistent inflammation and pulmonary fibrosis. However, details of the mechanisms associated with the regulation of acetylated modification in silicosis have yet to be sufficiently established. Furthermore, studies on the efficient delivery of DNA to lung tissues by nebulized inhalation for the treatment of silicosis are limited. In this study, we established a mouse model of silicosis successfully. Differentially expressed genes (DEGs) between the lung tissues of silicosis and control mice were identified based on transcriptomic analysis, and HDAC10 was the only DEG among the HDACs. Acetylomic and combined acetylomic/proteomic analysis were performed and found that the differentially expressed acetylated proteins have diverse biological functions, among which 12 proteins were identified as the main targets of HDAC10. Subsequently, HDAC10 expression levels were confirmed to increase following nebulized inhalation of linear poly(β-amino ester) (LPAE)-HDAC10 nanocomplexes. The levels of oxidative stress, the phosphorylation of IKKβ, IκBα and p65, as well as inflammation were inhibited by HDAC10. Pulmonary fibrosis, and lung function in silicosis showed significant improvements in response to the upregulation of HDAC10. Similar results were obtained for the silica-treated macrophages in vitro. In conclusion, HDAC10 was identified as the main mediator of acetylation in silicosis. Nebulized inhalation of LPAE-HDAC10 nanocomplexes was confirmed to be a promising treatment option for silicosis. The ROS/NF-κB pathway was identified as an essential signaling pathway through which HDAC10 attenuates oxidative stress, inflammation, and pulmonary fibrosis in silicosis. This study provides a new theoretical basis for the treatment of silicosis.

Microparticle-mediated CRISPR DNA delivery for genome editing in poplar.

The use of CRISPR/Cas9 is currently the method of choice for precise genome engineering in plants, including in the biomass crop poplar. The most commonly used method for delivering CRISPR/Cas9 and its components in poplar is via Agrobacterium-mediated transformation, that besides the desired gene-editing event also results in stable T-DNA integration. Here we explore the delivery of the gene-editing reagents via DNA-coated microparticle bombardment into the model tree Populus tremula x P. alba to evaluate its potential for developing transgene-free, gene-edited trees, as well as its potential for integrating donor DNA at specific target sites. Using an optimized transformation method, which favors the regeneration of plants that transiently express the genes on the delivered donor DNA, we regenerated gene-edited plants that are free of the Cas9 and the antibiotic resistance-encoding transgenes. In addition, we report the frequent integration of donor DNA fragments at the Cas9-induced double-strand break, opening opportunities toward targeted gene insertions.

Abstract 17370: Activation of Endothelial GCN2 Kinase Contributes to Pulmonary Vascular Remodeling and Pulmonary Arterial Hypertension

Rationale: Pulmonary arterial hypertension (PAH) is characterized by progressive increase of pulmonary vascular resistance and pulmonary vascular remodeling that result in right heart failure. Published studies show that recessive mutations in the EIF2AK4 gene (encoding GCN2, General control nonderepressibe 2 kinase) resulting in reduction of GCN2 are linked to heritable pulmonary veno-occlusive disease (PVOD) in patients and EIF2AK4 mutation was also found in PAH patients although very rare. Objective: To determine the role of endothelial GCN2 kinase in the pathogenesis of PAH. Results: Employing Eif2ak4 -/- mice, we found that loss of GCN2 induced neither spontaneous PVOD nor pulmonary hypertension (PH). In response to chronic hypoxia, loss of GCN2 inhibited hypoxia-induced PH and pulmonary vascular remodeling. RNA-sequencing analysis of mouse lung samples indicated Endothelin-1 as the downstream target of GCN2 in regulating pulmonary vascular remodeling and PH. In cultured human lung microvascular endothelial cells, GCN2 was phosphorylated and activated in response to hypoxia, which mediated hypoxia-induced Endothelin-1 expression through the GCN2/ATF4/HIF-2a/Endothelin-1 pathway. Endothelial cell-targeted nanoparticle delivery of plasmid DNA expressing Endothelin-1 selectively in endothelial cells in Eif2ak4 -/- mice markedly reversed the phenotype in response to hypoxia. Furthermore, nanoparticle delivery of the CRIPSR/Cas9 system-mediated knockout of Eif2ak4 in adult C57BL/6 mice also attenuated hypoxia-induced PH. Additionally, monocrotaline-induced vascular remodeling and PH in rats were inhibited by GCN2 inhibitor A-92 treatment. In lung samples of idiopathic PAH patients, we observed endothelial GCN2 hyperphosphorylation of pulmonary vascular lesions, without marked differences in GCN2 mRNA and protein levels compared to normal donor lungs. Conclusion: These studies demonstrate that endothelial GCN2 activation mediates pulmonary vascular remodeling and PAH development through the GCN2/ATF4/HIF-2a/Endothelin-1 pathway. Targeting GCN2 signaling is a promising therapeutic strategy for treatment of PAH in patients without GCN2 loss of function mutations.

Nucleic acid delivery to retinal cells using lipopeptides as a potential tool towards ocular gene therapies

We evaluated the use of lipopeptides capable to bind to nucleic acids towards plasmid DNA (pDNA) delivery. The investigations were particularly focused on arising retinal pigment epithelial cells (ARPE-19) as motivated by the considerable number of ocular disorders linked to gene aberrations. The lipopeptides comprised the artificial oligoamino acid succinyl-tetraethylene pentamine (Stp) as well as incorporated lysines, histidines, cysteines, fatty acids, and tyrosine trimers. Regardless of the structural differences, the lipopeptides demonstrated to efficiently condense pDNA at nitrogen-to-phosphate molar ratio (N/P) ≥ 6. Spheric nanoparticles were observed by cryo-TEM and dynamic light scattering determined hydrodynamic sizes ranging from 50 to 130 nm. The biological assays evidenced highly efficient pDNA delivery with a lower degree of cytotoxicity compared to the well-known transfecting agent linear polyethylenimine (LPEI). Although more efficient than LPEI, cysteine-containing carriers were demonstrated to be less efficient than the other counterparts possibly due to exceeding polyplex stabilization via disulfide cross links, which could hamper pDNA unpacking at the target site. Therefore, clearly a balance between complex stability and cargo release should be taken into account to optimize the transfection efficiency of the non-viral vectors. The gene transfer activity in ARPE-19 cells suggests the applicability of this kind of carrier for ocular treatments based on retinal gene delivery.