Exosomes as an Emerging Plasmid Delivery Vehicle for Gene Therapy

Expanding the role of exosomes in drug, biomolecule, and nanoparticle delivery

Exosomes are nanoscale extracellular vesicles released by diverse cell types, serving essential functions in intercellular communication and physiological processes. These vesicles have garnered considerable interest in recent years for their potential as drug delivery systems, attributed to their natural origin, minimal immunogenicity, high biocompatibility, and capacity to traverse biological barriers, including the blood-brain barrier. Exosomes can be obtained from diverse biological fluids, rendering them accessible and versatile vehicles for therapeutic medicines. This study emphasizes the burgeoning significance of exosomes in drug administration, concentrating on their benefits, including improved stability, target selectivity, and the capacity to encapsulate various biomolecules, such as proteins, nucleic acids, and small molecules. Notwithstanding their potential applications, other problems remain, including as effective drug loading, industrial scalability, and the standardization of isolation methodologies. Overcoming these hurdles via new research is essential for fully harnessing the promise of exosomes in therapeutic applications, especially in the treatment of intricate diseases like cancer and neurological disorders.

The Role of Exosomes in Central Immune Tolerance and Myasthenia Gravis

BACKGROUND

Immune homeostasis plays a crucial role in immunology andis dependent on both central and peripheral tolerance. Centraltolerance and peripheral tolerance occur in the thymus and thesecondary lymphoid tissues, respectively. Tolerance breakdown andimmune regulation defects can lead to autoimmune disorders. In thisreview article, we aimed to describe the role of exosomes inregulating central tolerance and provide a summary of their effectson the pathogenesis, diagnosis, and therapeutic potential inmyasthenia gravis (MG).

METHODS

Articles for this review wereidentified using the PubMed database.

RESULTS

As the primarylymphoid organ, the thymus is responsible for building an immunecompetent, yet self-tolerant of T-cell population. Thymic statesinclude thymoma, thymic hyperplasia, and thymic atrophy, which canexert a significant influence on the central immune tolerance andrepresent specific characteristics of MG. Previous studies have foundthat exosomes derived from human thymic epithelial cells carryantigen-presenting molecules and a wide range of tissue restrictedantigens, which may indicate a vital role of thymic exosomes in MG.Besides, exosomal miRNAs and lncRNAs may also play a critical role inthe pathophysiology of MG.

CONCLUSION

This review provides thetherapeutic and diagnostic potential of exosomes in MG patients.

Harnessing the Potential of Exosomes in Therapeutic Interventions for Brain Disorders

Exosomes, which are nano-sized natural vesicles secreted by cells, are crucial for intercellular communication and interactions, playing a significant role in various physiological and pathological processes. Their characteristics, such as low toxicity and immunogenicity, high biocompatibility, and remarkable drug delivery capabilities-particularly their capacity to traverse the blood-brain barrier-make exosomes highly promising vehicles for drug administration in the treatment of brain disorders. This review provides a comprehensive overview of exosome biogenesis and isolation techniques, strategies for the drug loading and functionalization of exosomes, and exosome-mediated blood-brain barrier penetration mechanisms, with a particular emphasis on recent advances in exosome-based drug delivery for brain disorders. Finally, we address the opportunities and challenges associated with utilizing exosomes as a drug delivery system for the brain, summarizing the barriers to clinical translation and proposing future research directions.

Nano Approaches to Nucleic Acid Delivery: Barriers, Solutions, and Current Landscape

Nucleic acid (NA) therapy holds tremendous potential for treating a wide range of genetic diseases by the delivery of therapeutic genes into target cells. However, significant challenges exist in safely and effectively delivering these genes to their intended locations. Viral vectors, though efficient, pose risks such as immunogenicity and mutagenesis. This has resulted in growing interest in non-viral, nanoparticle-based NA delivery systems. This review article describes various physiological barriers to NA delivery and explores nanoparticle-based NA delivery systems, including bioengineered nanoparticles, peptides, lipid nanoparticles, and polymeric nanoparticles, highlighting their unique features to overcome in vivo barriers for NA delivery. While these nanoparticle-based NA delivery systems offer a promising alternative to viral vectors, challenges related to cytotoxicity, reproducible synthesis, and cost need to be addressed. The current clinical landscape of NA delivery is also discussed, emphasizing the need for safer, scalable, and cost-effective solutions. Nanoparticles represent a promising future in NA therapy, with the possibility of developing clinically relevant, non-toxic, stable, and non-immunogenic delivery vehicles, paving the way for broader therapeutic applications and improved clinical outcomes.

Exosome-membrane and polymer-based hybrid-complex for systemic delivery of plasmid DNA into brains for the treatment of glioblastoma

Herpes simplex virus thymidine kinase (HSVtk) gene therapy is a promising strategy for glioblastoma therapy. However, delivery of plasmid DNA (pDNA) encoding HSVtk into the brain by systemic administration is a challenge since pDNA can hardly penetrate the blood-brain barrier. In this study, an exosome-membrane (EM) and polymer-based hybrid complex was developed for systemic delivery of pDNA into the brain. Histidine/arginine-linked polyamidoamine (PHR) was used as a carrier. PHR binds to pDNA by electrostatic interaction. The pDNA/PHR complex was mixed with EM and subjected to extrusion to produce pDNA/PHR-EM hybrid complex. For glioblastoma targeting, T7 peptide was attached to the pDNA/PHR-EM complex. Both pDNA/PHR-EM and T7-decorated pDNA/PHR-EM (pDNA/PHR-EM-T7) had a surface charge of -5 mV and a size of 280 nm. Transfection assays indicated that pDNA/PHR-EM-T7 enhanced the transfection to C6 cells compared with pDNA/PHR-EM. Intravenous administration of pHSVtk/PHR-EM-T7 showed that pHSVtk/PHR-EM and pHSVtk/PHR-EM-T7 delivered pHSVtk more efficiently than pHSVtk/lipofectamine and pHSVtk/PHR into glioblastoma in vivo. pHSVtk/PHR-EM-T7 had higher delivery efficiency than pHSVtk/PHR-EM. As a result, the HSVtk expression and apoptosis levels in the tumors of the pHSVtk/PHR-EM-T7 group were higher than those of the other control groups. Therefore, the pDNA/PHR-EM-T7 hybrid complex is a useful carrier for systemic delivery of pHSVtk to glioblastoma.

Exploring precision treatments in immune-mediated inflammatory diseases: Harnessing the infinite potential of nucleic acid delivery

Immune-mediated inflammatory diseases (IMIDs) impose an immeasurable burden on individuals and society. While the conventional use of immunosuppressants and disease-modifying drugs has provided partial relief and control, their inevitable side effects and limited efficacy cast a shadow over finding a cure. Promising nucleic acid drugs have shown the potential to exert precise effects at the molecular level, with different classes of nucleic acids having regulatory functions through varying mechanisms. For the better delivery of nucleic acids, safe and effective viral vectors and non-viral delivery systems (including liposomes, polymers, etc.) have been intensively explored. Herein, after describing a range of nucleic acid categories and vectors, we focus on the application of therapeutic nucleic acid delivery in various IMIDs, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, multiple sclerosis, asthma, ankylosing spondylitis, systemic lupus erythematosus, and uveitis. Molecules implicated in inflammation and immune dysregulation are abnormally expressed in a series of IMIDs, and their meticulous modulation through nucleic acid therapy results in varying degrees of remission and improvement of these diseases. By synthesizing findings centered on specific molecular targets, this review delivers a systematic elucidation and perspective towards advancing and utilization of nucleic acid therapeutics for managing IMIDs.

3'-UTR Sequence of Exosomal NANOGP8 DNA as an Extracellular Vesicle-Localization Signal

Extracellular vesicles (EVs) are garnering attention as a safe and efficient biomolecule delivery system. EVs intrinsically play a crucial role in intercellular communication and pathophysiology by transporting functionally active DNA molecules. The internalized DNA pleiotropically affects the recipient cells. Considering these salient features, an intentional incorporation of specific DNA gene cassettes into EVs and their subsequent delivery to the target cells has potential applications in genetic engineering. Moreover, efficient ways to insert the DNA into EVs during their biogenesis is valuable. Our current research is a step in the development of this technology. As such, cancer cells are known to secrete exosomes containing increased amounts of double-stranded DNA than normal cells. The clonal analysis in our previously published data revealed that exosomes released from various cancer cells contained a significantly larger population of NANOGP8 DNA with a 22-base pair insertion in the 3'-untranslated region (UTR) compared to those secreted by normal cells. This finding led us to hypothesize that the 22-base pair insertion may act as a signal to facilitate the incorporation of NANOGP8 DNA into the exosomes. To test this hypothesis, we compared the EV localization of an Enhanced Green Fluorescent Protein (EGFP) gene fused with the NANOGP8 3'-UTR, with and without the 22-base pair insertion. The quantitative PCR analysis showed a significantly higher EGFP DNA accumulation in exosomes released from cells transfected with the gene cassette containing the 3'-UTR with the 22-base pair insertion. The discovery of a DNA localization signal in exosomal DNA's 3'-UTR could pave the way for the development of an EV-based DNA delivery system. This technology will open new possibilities in genetic engineering and innovative therapies using nucleic acid medicine.

Precise genome-editing in human diseases: mechanisms, strategies and applications

Precise genome-editing platforms are versatile tools for generating specific, site-directed DNA insertions, deletions, and substitutions. The continuous enhancement of these tools has led to a revolution in the life sciences, which promises to deliver novel therapies for genetic disease. Precise genome-editing can be traced back to the 1950s with the discovery of DNA's double-helix and, after 70 years of development, has evolved from crude in vitro applications to a wide range of sophisticated capabilities, including in vivo applications. Nonetheless, precise genome-editing faces constraints such as modest efficiency, delivery challenges, and off-target effects. In this review, we explore precise genome-editing, with a focus on introduction of the landmark events in its history, various platforms, delivery systems, and applications. First, we discuss the landmark events in the history of precise genome-editing. Second, we describe the current state of precise genome-editing strategies and explain how these techniques offer unprecedented precision and versatility for modifying the human genome. Third, we introduce the current delivery systems used to deploy precise genome-editing components through DNA, RNA, and RNPs. Finally, we summarize the current applications of precise genome-editing in labeling endogenous genes, screening genetic variants, molecular recording, generating disease models, and gene therapy, including ex vivo therapy and in vivo therapy, and discuss potential future advances.