DNA-Based Nonviral Gene Therapy─Challenging but Promising

A review of the progress and challenges of developing dendritic-based vaccines against hepatitis B virus (HBV)

Hepatitis B virus (HBV) infections that last a long time are a significant public health problem worldwide. About 254 million people around the world are chronically sick with HBV. Each year, 1.2 million new cases occur, and in 2022, 1.1 million people will die from the disease. So, it has been essential to work on finding ways to treat and avoid HBV. The process of therapeutic vaccination involves giving people a non-infectious form of a virus to start or improve immune reactions specific to HBV. This helps keep HBV infections under control. Dendritic cells (DCs) play a significant part in beginning the adaptive immune response, which could decide how well an HBV infection is treated. DC-based treatment has been looked into for people with chronic HBV (CHB) infection and has shown some sound effects. Vaccines for CHB that use DCs boost antiviral immunity by improving T cells and breaking the immune system's resistance against HBV. In these vaccines, DCs are loaded with HBV antigens (like HBsAg, HBcAg, or peptides) outside of the body and then put back into the patient to make the immune system work better. In conclusion, this DC treatment is a biological therapy method with a good chance of being used. This study examined the different DC-based medicines that can treat and prevent HBV. Finally, we've talked about clinical studies, the current problems, how to fix them, and the future of this vaccine for treating and preventing HBV.

Nanoparticle-mediated enhancement of DNA Vaccines: Revolutionizing immunization strategies

DNA vaccines are a novel form of vaccination that aims to harness genetic material to produce targeted immune responses. Nevertheless, their therapeutic application is hampered by low transfection efficacy, immunogenicity, and instability. Nanoparticle (NP) - based delivery systems are beneficial in enhancing DNA stability, increasing DNA uptake by antigen-presenting cells (APCs), and controlling antigen release. Some key progress includes the polymeric, lipid-based, and hybrid NPs and biocompatible carriers with inherent adjuvant effects. These systems have helped to enhance the antigen cross-presentation and T-cell activation significantly. In addition, biocompatible hybrid nanocarriers, antigen cross-presentation strategies, and next-generation sequencing (NGS) technologies are speeding up the identification of new antigens, while AI and machine learning are facilitating the development of efficient delivery systems. This review aims to assess how NPs have contributed to improving the effectiveness of DNA vaccines for treating diseases, cancer, and emerging diseases, as well as advancing the next generation of DNA vaccines.

A critical view of silk fibroin for non-viral gene therapy

Exogenous genes are inserted into target cells during gene therapy in order to compensate or rectify disorders brought on by faulty or aberrant genes. However, gene therapy is still in its early stages because of its unsatisfactory therapeutic effects which are mainly due to low transfection efficiency of vectors, high toxicity, and poor target specificity. A natural polymer with numerous bioactive sites, good mechanical qualities, biodegradability, biocompatibility, and processability called silk fibroin has gained attention as a possible gene therapy vector. Using silk fibroin as a gene vector can reduce cell toxicity, extend the duration of gene expression, and allow further release even in the bloodstream, thereby expanding its therapeutic scope. This review outlines the advancements made with regard to gene delivery methods based on silk fibroin materials in the fields of malignant tumors, bone tissue regeneration, neural tissue, and vascular tissue engineering. Silk fibroin exhibits remarkable repair and therapeutic effects in gene therapy and can be employed in numerous forms, such as a vector (nanoparticles, microcapsules) or a matrix (hydrogel, scaffold) for gene delivery.

Non-viral gene therapy for Leber's congenital amaurosis: progress and possibilities

Leber's congenital amaurosis (LCA) represents a set of rare and pervasive hereditary conditions of the retina that cause severe vision loss starting in early childhood. Targeted treatment intervention has become possible thanks to recent advances in understanding LCA genetic basis. While viral vectors have shown efficacy in gene delivery, they present challenges related to safety, low cargo capacity, and the potential for random genomic integration. Non-viral gene therapy is a safer and more flexible alternative to treating the underlying genetic mutation causing LCA. Non-viral gene delivery methods, such as inorganic nanoparticles, polymer-based delivery systems, and lipid-based nanoparticles, bypass the risks of immunogenicity and genomic integration, potentially offering a more versatile and personalized treatment for patients. This review explores the genetic background of LCA, emphasizing the mutations involved, and explores diverse non-viral gene delivery methods being developed. It also highlights recent studies on non-viral gene therapy for LCA in animal models and clinical trials. It presents future perspectives for gene therapy, including integrating emerging technologies like CRISPR-Cas9, interdisciplinary collaborations, personalized medicine, and ethical considerations.

Synthesizing unmodified, supercoiled circular DNA molecules in vitro

Supercoiled (Sc) circular DNA, such as plasmids, has shown therapeutic potential since the 1990s, but is limited by bacterial modifications, unnecessary DNA sequences, and contaminations that may trigger harmful responses. To overcome these challenges, we have developed two novel scalable biochemical methods to synthesize unmodified Sc circular DNA. Linear DNA with two loxP sites in the same orientation is generated via PCR or rolling circle amplification. Cre recombinase then converts this linear DNA into relaxed circular DNA. After T5 exonuclease removes unwanted linear DNA, topoisomerases are employed to generate Sc circular DNA. We have synthesized EGFP-FL, a 2,002 bp mini-circular DNA carrying essential EGFP expression elements. EGFP-FL transfected human HeLa and mouse C2C12 cells with much higher efficiency than E. coli-derived plasmids. These new biochemical methods can produce unmodified Sc circular DNA, in length from 196 base pairs to several kilobases and in quantities from micrograms to milligrams, providing a promising platform for diverse applications.

Review on the bioanalysis of non-virus-based gene therapeutics

Over the past years, gene therapeutics have held great promise for treating many inherited and acquired diseases. The increasing number of approved gene therapeutics and developing clinical pipelines demonstrate the potential to treat diseases by modifying their genetic blueprints in vivo. Compared with conventional treatments targeting proteins rather than underlying causes, gene therapeutics can achieve enduring or curative effects via gene activation, inhibition, and editing. However, the delivery of DNA/RNA to the target cell to alter the gene expression is a complex process that involves, crossing numerous barriers in both the extracellular and intracellular environment. Generally, the delivery strategies can be divided into viral-based and non-viral-based vectors. This review summarizes various bioanalysis strategies that support the non-virus-based gene therapeutics research, including pharmacokinetics (PK)/toxicokinetics (TK), biodistribution, immunogenicity evaluations for the gene cargo, vector, and possible expressed protein, and highlights the challenges and future perspectives of bioanalysis strategies in non-virus-based gene therapeutics. This review may provide new insights and directions for the development of emerging bioanalytical methods, offering technical support and a research foundation for innovative gene therapy treatments.

Coassembly of a Hybrid Synthetic-Biological Chitosan-g-Poly(N-isopropylacrylamide) Copolymer with DNAs of Different Lengths

Natural polysaccharides can serve as carriers of genes owing to their intrinsic biocompatibility, biodegradability, and low toxicity. Additionally, they can be easily chemically modified, e.g., through grafting, leading to hybrid synthetic-biological copolymers with additional functionalities. In this work we report on the electrostatic interaction between a chitosan-g-poly(N-isopropylacrylamide) (Chit-g-PNIPAM) copolymer and DNA macromolecules of different lengths (i.e., 50 and 2000 bp), towards the construction of polyplexes that can serve as potential gene delivery systems. At the basic science level, the work aims to elucidate the effects of DNA length on the structural and physicochemical properties of the thermoresponsive hybrid macromolecular assemblies. The protonated amino groups on the chitosan backbone enable electrostatic binding with the anionic phosphate groups of the DNA molecules, while the PNIPAM side chains are expected to impart thermoresponsive properties to the formed polyplexes. Different amino to phosphate group (N/P) mixing ratios were examined, aiming to produce stable dispersions. The physicochemical properties of the resulting polyplexes were investigated by dynamic and electrophoretic light scattering (DLS and ELS), while their morphology was studied by scanning-transmission electron microscopy (STEM). Moreover, their response to changes in temperature and ionic strength, as well as their stability against biological media, was also examined. Finally, the binding affinity of the copolymer towards DNA was evaluated through fluorescence spectroscopy, using ethidium bromide quenching assays, while infrared spectroscopy was used to investigate the structure of the incorporated DNA chains.

Quinine-Based Polymers Are Versatile and Effective Vehicles for Intracellular pDNA, mRNA, and Cas9 Protein Delivery

Quinine-based polymers have previously demonstrated promising performance in delivering pDNA in cells owing to their electrostatic as well as the nonelectrostatic interactions with pDNA. Herein, we evaluate whether quinine-based polymers are versatile for delivery of mRNA and Cas9-sgRNA complexes, especially in a serum-rich environment. Both mRNA and the Cas9-sgRNA complex are potent therapeutics that are structurally, chemically, and functionally very different from pDNA. By exploring a family of 7 quinine-based polymers that vary in monomer structure and polymer composition, we tested numerous formulations (42 with pDNA, 96 with mRNA, and 48 with Cas9-sgRNA) for payload-polymer complexation and delivery to compare payload-dependent structure-activity relationships. Several formulations demonstrated performance comparable to or better than the commercially available transfection agent jetPEI. The results of this study demonstrate the potential of quinine-based as a versatile carrier platform for delivering a wide range of nucleic acid therapeutics and serving the drug delivery needs in the field genetic medicine.

Targeted Delivery of Circular Single-Stranded DNA Encoding IL-12 for the Treatment of Triple-Negative Breast Cancer

Interleukin-12 (IL-12) is a critical cytokine with notable anticancer properties, including enhancing T-cell-mediated cancer cell killing, and curbing tumor angiogenesis. To date, many approaches are evaluated to achieve in situ overexpression of IL-12, minimizing leakage and the ensuing toxicity. Here, it is focused on circular single-stranded DNA (Css DNA), a type of DNA characterized by its unique structure, which could be expressed in mammals. It is discovered that Css DNA can induce sustained luciferase expression for half a year by intramuscular injection and showed effective antitumor results by intratumoral injection. Motivated by these findings, a folate-modified LNP system is now developed for the delivery of Css DNA expressing IL-12 for the therapy of 4T1 triple-negative breast cancer (TNBC). This delivery system effectively activates anti-cancer immune responses, slows tumor growth, significantly prolongs survival in animal models, and prevents tumor recurrence. After 6 months of long-term observation, the elevated level of IL-12 is still detectable in the lymph nodes and serum of the cured mice. This study highlights the long-term sustained expression capacity of Css DNA and its ability to inhibit recurrence, and the potential of tumor-targeted LNPs for Css DNA-based cancer therapy, providing a new insight into gene overexpression strategy.

Monoclonal Antibody Delivery Using 3D Printed Biobased Hollow μNe3dle Arrays for the Treatment of Osteoporosis

Transdermal microneedles have demonstrated promising potential as an alternative to typical drug administration routes for the treatment of various diseases. As microneedles offer lower administration burden with enhanced patient adherence and reduced ecological footprint, there is a need for further exploitation of microneedle devices. One of the main objectives of this work was to initially develop an innovative biobased photocurable resin with high biobased carbon content comprising isobornyl acrylate (IBA) and pentaerythritol tetraacrylate blends (50:50 wt/wt). The optimization of the printing and curing process resulted in μNe3dle arrays with durable mechanical properties and piercing capacity. Another objective of the work was to employ the 3D printed hollow μNe3dles for the treatment of osteoporosis in vivo. The 3D printed μNe3dle arrays were used to administer denosumab (Dmab), a monoclonal antibody, to osteoporotic mice, and the serum concentrations of critical bone minerals were monitored for six months to assess recovery. It was found that the Dmab administered by the 3D printed μNe3dles showed fast in vitro rates and induced an enhanced therapeutic effect in restoring bone-related minerals compared to subcutaneous injections. The findings of this study introduce a novel green approach with a low ecological footprint for 3D printing of biobased μNe3dles, which can be tailored to improve clinical outcomes and patient compliance for chronic diseases.

Harnessing DNA origami's therapeutic potential for revolutionizing cardiovascular disease treatment: A comprehensive review

DNA origami is a cutting-edge nanotechnology approach that creates precise and detailed 2D and 3D nanostructures. The crucial feature of DNA origami is how it is created, which enables precise control over its size and shape. Biocompatibility, targetability, programmability, and stability are further advantages that make it a potentially beneficial technique for a variety of applications. The preclinical studies of sophisticated programmable nanomedicines and nanodevices that can precisely respond to particular disease-associated triggers and microenvironments have been made possible by recent developments in DNA origami. These stimuli, which are endogenous to the targeted disorders, include protein upregulation, pH, redox status, and small chemicals. Oncology has traditionally been the focus of the majority of past and current research on this subject. Therefore, in this comprehensive review, we delve into the intricate world of DNA origami, exploring its defining features and capabilities. This review covers the fundamental characteristics of DNA origami, targeting DNA origami to cells, cellular uptake, and subcellular localization. Throughout the review, we emphasised on elucidating the imperative for such a therapeutic platform, especially in addressing the complexities of cardiovascular disease (CVD). Moreover, we explore the vast potential inherent in DNA origami technology, envisioning its promising role in the realm of CVD treatment and beyond.

Synthesis of Thermoresponsive Chitosan-graft-Poly(N-isopropylacrylamide) Hybrid Copolymer and Its Complexation with DNA

A hybrid synthetic-natural, thermoresponsive graft copolymer composed of poly(N-isopropyl acrylamide) (PNIPAM) side chains, prepared via RAFT polymerization, and a chitosan (Chit) polysaccharide backbone, was synthesized via radical addition-fragmentation reactions using the "grafting to" technique, in aqueous solution. ATR-FTIR, TGA, polyelectrolyte titrations and 1H NMR spectroscopy were employed in order to validate the Chit-g-PNIPAM copolymer chemical structure. Additionally, 1H NMR spectra and back conductometric titration were utilized to quantify the content of grafted PNIPAM side chains. The resulting graft copolymer contains dual functionality, namely both pH responsive free amino groups, with electrostatic complexation/coordination properties, and thermoresponsive PNIPAM side chains. Particle size measurements via dynamic light scattering (DLS) were used to study the thermoresponsive behavior of the Chit-g-PNIPAM copolymer. Thermal properties examined by TGA showed that, by the grafting modification with PNIPAM, the Chit structure became more thermally stable. The lower critical solution temperature (LCST) of the copolymer solution was determined by DLS measurements at 25-45 °C. Furthermore, dynamic and electrophoretic light scattering measurements demonstrated that the Chit-g-PNIPAM thermoresponsive copolymer is suitable of binding DNA molecules and forms nanosized polyplexes at different amino to phosphate groups ratios, with potential application as gene delivery systems.

Between hope and reality: treatment of genetic diseases through nucleic acid-based drugs

Rare diseases (RD) affect a small number of people compared to the general population and are mostly genetic in origin. The first clinical signs often appear at birth or in childhood, and patients endure high levels of pain and progressive loss of autonomy frequently associated with short life expectancy. Until recently, the low prevalence of RD and the gatekeeping delay in their diagnosis have long hampered research. The era of nucleic acid (NA)-based therapies has revolutionized the landscape of RD treatment and new hopes arise with the perspectives of disease-modifying drugs development as some NA-based therapies are now entering the clinical stage. Herein, we review NA-based drugs that were approved and are currently under investigation for the treatment of RD. We also discuss the recent structural improvements of NA-based therapeutics and delivery system, which overcome the main limitations in their market expansion and the current approaches that are developed to address the endosomal escape issue. We finally open the discussion on the ethical and societal issues that raise this new technology in terms of regulatory approval and sustainability of production.