Nonviral gene delivery to T cells with Lipofectamine LTX

T Cell-Targeting Nanotherapies for Atherosclerosis

Cardiovascular diseases remain the leading cause of mortality worldwide. Specifically, atherosclerosis is a primary cause of acute cardiac events. However, current therapies mainly focus on lipid-lowering versus addressing the underlying inflammatory response that leads to its development and progression. Nanoparticle-mediated drug delivery offers a promising approach for targeting and regulating these inflammatory responses. In atherosclerotic lesions, inflammatory cascades result in increased T helper (Th) 1 and Th17 activity and reduced T regulatory activation. The regulation of T cell responses is critical in preventing the inflammatory imbalance in atherosclerosis, making them a key therapeutic target for nanotherapy to achieve precise atherosclerosis treatment. By functionalizing nanoparticles with targeting modalities, therapeutic agents can be delivered specifically to immune cells in atherosclerotic lesions. In this Review, we outline the role of T cells in atherosclerosis, examine current nanotherapeutic strategies for targeting T cells and modulating their differentiation, and provide perspectives for the development of nanoparticles specifically tailored to target T cells for the treatment of atherosclerosis.

Enhancing non-viral DNA delivery systems: Recent advances in improving efficiency and target specificity

DNA-based therapies are often limited by challenges such as stability, long-term integration, low transfection efficiency, and insufficient targeted DNA delivery. This review focuses on recent progress in the design of non-viral delivery systems for enhancing targeted DNA delivery and modulation of therapeutic efficiency. Cellular uptake and intracellular trafficking mechanisms play a crucial role in optimizing gene delivery efficiency. There are two main strategies employed to improve the efficiency of gene delivery vectors: (i) explore different administration routes (e.g., mucosal, intravenous, intramuscular, subcutaneous, intradermal, intratumoural, and intraocular) that best facilitates optimal uptake into the targeted cells and organs and (ii) modify the delivery vectors with cell-specific ligands (e.g., natural ligands, antibodies, peptides, carbohydrates, or aptamers) that enable targeted uptake to specific cells with higher specificity and improved biodistribution. We describe how recent progress in employing these DNA delivery strategies is advancing the field and increasing the clinical translation and ultimate clinical application of DNA therapies.

Enhancing non-viral gene delivery to human T cells through tuning nanoparticles physicochemical features, modulation cellular physiology, and refining transfection strategies

Genetically engineered immune cells hold great promise for treating immune-related diseases, but their development is hindered by technical challenges, primarily related to nucleic acid delivery. Polyethylenimine (PEI) is a cost-effective transfection agent, yet it requires significant optimization for effective T cell transfection. In this study, we comprehensively fine-tuned the characteristics of PEI/DNA nanoparticles, culture conditions, cellular physiology, and transfection protocols to enhance gene delivery into T cells. Gel retardation and dynamic light scattering (DLS) analyses confirmed that PEI effectively bound to DNA, forming size- and charge-adjustable particles based on the N/P ratio, which remained stable in RPMI 1640 medium for 3 days at 25°C. At an N/P ratio of 8.0, these nanoparticles achieved an optimal transfection rate, which improved further with adjustments in DNA dosage and complex volume. Additionally, increasing the cell seeding density and adding complete media shortly after transfection significantly boosted PEI-mediated gene delivery. Notably, reversing the transfection in vials resulted in a 20-fold increase in cellular uptake and transfection efficiency compared to the conventional direct transfection method in culture plates. Finally, modifying cellular physiology with hypotonic extracellular media at pH 9.0 dramatically enhanced transfection rates while maintaining minimal cytotoxicity. These findings could reduce the cost and complexity of preparing engineered T cells, potentially accelerating the development of immune cell therapies for human diseases.

Genetically modified organoids for tissue engineering and regenerative medicine

To date, genetically modified organoids are emerging as a promising 3D modeling tool aimed at solving genetically relevant clinical and biomedical problems for regenerative medicine and tissue engineering. As an optimal vehicle for gene delivery, genetically modified organoids can enhance or reduce the expression of target genes through virus and non-virus-based gene transfection methods to achieve tissue regeneration. Animal experiments and preclinical studies have demonstrated the beneficial role of genetically modified organoids in various aspects of organ regeneration, including thymus, lacrimal glands, brain, lung, kidney, photoreceptors, etc. Furthermore, the technology offers a potential treatment option for various diseases, such as Fabry disease, non-alcoholic steatohepatitis, and Lynch syndrome. Nevertheless, the uncertain safety of genetic modification, the risk of organoid application, and bionics of current genetically modified organoids are still challenging. This review summarizes the researches on genetically modified organoids in recent years, and describes the transfection methods and functions of genetically modified organoids, then introduced their applications at length. Also, the limitations and future development directions of genetically modified organoids are included.

Nanoparticle-mediated universal CAR-T therapy

In recent years, chimeric antigen receptor (CAR)-T cell therapy has been highly successful in treating hematological malignancies, leading to significant advancements in the cancer immunotherapy field. However, the typical CAR-T therapy necessitates the enrichment of patients' own leukocytes for ex vivo production of CAR-T cells, this customized pattern requires a complicated and time-consuming manufacturing procedure, making it costly and less accessible. The off-the-shelf universal CAR-T strategy could reduce manufacturing costs and realize timely drug administration, presenting as an ideal substitute for typical CAR-T therapy. Utilizing nanocarriers for targeted gene delivery is one of the approaches for the realization of universal CAR-T therapy, as biocompatible and versatile nanoparticles could deliver CAR genes to generate CAR-T cells in vivo. Nanoparticle-mediated in situ generation of CAR-T cells possesses multiple advantages, including lowered cost, simplified manufacturing procedure, and shortened administration time, this strategy is anticipated to provide a potentially cost-effective alternative to current autologous CAR-T cell manufacturing, thus facilitating the prevalence and improvement of CAR-T therapy.

Tailoring lipid nanoparticles for T-cell targeting in allergic asthma: Insights into efficacy and specificity

Asthma impacts over 300 million patients globally, with significant health implications, especially in cases of its allergic subtype. The disease is characterized by a complex interplay of airway inflammation and immune responses, often mediated by Th2 cell-related cytokines. In this study, we engineered lipid nanoparticles (LNPs) to specifically deliver therapeutic siRNA via the transferrin receptor to T cells. Strain-promoted azide-alkyne cycloaddition (SPAAC) was employed for the conjugation of transferrin ligands to PEGylated lipids in the LNPs, with the goal of enhancing cellular uptake and gene knockdown. The obtained LNPs exhibited characteristics that make them suitable for pulmonary delivery. Using methods such as nanoparticle tracking analysis (NTA) and enzyme-linked immunosorbent assay (ELISA), we determined the average number of transferrin molecules bound to individual LNPs. Additionally, we found that cellular uptake was ligand-dependent, achieving a GATA3 knockdown of more than 50% in relevant in vitro and ex vivo models. Notably, our findings highlight the limitations inherent to modifying the surface of LNPs, particularly with regard to their targeting capabilities. This work paves the way for future research aimed at optimizing targeted LNPs for the treatment of immunologic diseases such as allergic asthma.

A solution for highly efficient electroporation of primary cytotoxic T lymphocytes

BACKGROUND

Cytotoxic T lymphocytes (CTLs) are central players in the adaptive immune response. Their functional characterization and clinical research depend on efficient and reliable transfection. Although various methods have been utilized, electroporation remains the preferred technique for transient gene over-expression. However, the efficiency of electroporation is reduced for human and mouse primary CTLs. Lonza offers kits that effectively improve plasmid DNA transfection quality. Unfortunately, the removal of key components of the cell recovery medium considerably reduced the efficiency of their kit for CTLs. Our aim was to develop a new recovery medium to be used with Lonza's Nucleofector system that would significantly enhance transfection rates.

RESULTS

We assessed the impact of different media in which the primary CTLs were placed to recover after electroporation on cell survival, transfection rate and their ability to form an immunological synapse and to perform exocytosis. We transfected the cells with pmax-GFP and large constructs encoding for either CD81-super ecliptic pHluorin or granzyme B-pHuji. The comparison of five different media for mouse and two for human CTLs demonstrated that our new recovery medium composed of Opti-MEM-GlutaMAX supplemented with HEPES, DMSO and sodium pyruvate gave the best result in cell survival (> 50%) and transfection rate (> 30 and 20% for mouse and human cells, respectively). More importantly, the functionality of CTLs was at least twice as high as with the original Lonza recovery medium. In addition, our RM significantly improved transfection efficacy of natural killer cells that are notoriously hard to electroporate.

CONCLUSION

Our results show that successful transfection depends not only on the electroporation medium and pulse sequence but also on the medium applied for cell recovery. In addition, we have reduced our reliance on proprietary products by designing an effective recovery medium for both mouse and human primary CTLs and other lymphocytes that can be easily implemented by any laboratory. We expect that this recovery medium will have a significant impact on both fundamental and applied research in immunology.

Charge-altering releasable transporters enhance mRNA delivery in vitro and exhibit in vivo tropism

The introduction of more effective and selective mRNA delivery systems is required for the advancement of many emerging biomedical technologies including the development of prophylactic and therapeutic vaccines, immunotherapies for cancer and strategies for genome editing. While polymers and oligomers have served as promising mRNA delivery systems, their efficacy in hard-to-transfect cells such as primary T lymphocytes is often limited as is their cell and organ tropism. To address these problems, considerable attention has been placed on structural screening of various lipid and cation components of mRNA delivery systems. Here, we disclose a class of charge-altering releasable transporters (CARTs) that differ from previous CARTs based on their beta-amido carbonate backbone (bAC) and side chain spacing. These bAC-CARTs exhibit enhanced mRNA transfection in primary T lymphocytes in vitro and enhanced protein expression in vivo with highly selective spleen tropism, supporting their broader therapeutic use as effective polyanionic delivery systems.

Gene Delivery into T-Cells Using Ternary Complexes of DNA, Lipofectamine, and Carboxy-Terminal Phenylalanine-Modified Dendrimers

T-cells play critical roles in various immune reactions, and genetically engineered T-cells have attracted attention for the treatment of cancer and autoimmune diseases. Previously, it is shown that a polyamidoamine dendrimer of generation 4 (G4), modified with 1,2-cyclohexanedicarboxylic anhydride (CHex) and phenylalanine (Phe) (G4-CHex-Phe), is useful for delivery into T-cells and their subsets. In this study, an efficient non-viral gene delivery system is constructed using this dendrimer. Ternary complexes are prepared using different ratios of plasmid DNA, Lipofectamine, and G4-CHex-Phe. A carboxy-terminal dendrimer lacking Phe (G3.5) is used for comparison. These complexes are characterized using agarose gel electrophoresis, dynamic light scattering, and ζpotential measurements. In Jurkat cells, the ternary complex with G4-CHex-Phe at a P/COOH ratio of 1/5 shows higher transfection activity than other complexes, such as binary and ternary complexes with G3.5, without any significant cytotoxicity. The transfection efficiency of the G4-CHex-Phe ternary complexes decreases considerably in the presence of free G4-CHex-Phe and upon altering the complex preparation method. These results suggest that G4-CHex-Phe promotes the cellular internalization of the complexes, which is useful for gene delivery into T-cells.

Polymer- and lipid-based gene delivery technology for CAR T cell therapy

Chimeric antigen receptor T cell (CAR T cell) therapy is a revolutionary approach approved by the FDA and EMA to treat B cell malignancies and multiple myeloma. The production of these T cells has been done through viral vectors, which come with safety concerns, high cost and production challenges, and more recently also through electroporation, which can be extremely cytotoxic. In this context, nanosystems can constitute an alternative to overcome the challenges associated with current methods, resulting in a safe and cost-effective platform. However, the barriers associated with T cells transfection show that the design and engineering of novel approaches in this field are highly imperative. Here, we present an overview from CAR constitution to transfection technologies used in T cells, highlighting the lipid- and polymer-based nanoparticles as a potential delivery platform. Specifically, we provide examples, strengths and weaknesses of nanosystem formulations, and advances in nanoparticle design to improve transfection of T cells. This review will guide the researchers in the design and development of novel nanosystems for next-generation CAR T therapeutics.

Transcriptomic analysis of the innate immune response to in vitro transfection of plasmid DNA

The innate immune response to cytosolic DNA is intended to protect the host from viral infections, but it can also inhibit the delivery and expression of therapeutic transgenes in gene and cell therapies. The goal of this work was to use mRNA sequencing to identify genes that may influence transfection efficiency in four different cell types (PC-3, Jurkat, HEK-293T, and primary T cells). The highest transfection efficiency was observed in HEK-293T cells, which upregulated only 142 genes with no known antiviral functions after transfection with lipofectamine. Lipofection upregulated 1,057 cytokine-stimulated genes (CSGs) in PC-3 cells, which exhibited a significantly lower transfection efficiency. However, when PC-3 cells were transfected in serum-containing media or electroporated, the observed transfection efficiencies were significantly higher while the expression levels of cytokines and CSGs decreased. In contrast, lipofection of Jurkat and primary T cells only upregulated a few genes, but several of the antiviral CSGs that were absent in HEK-293T cells and upregulated in PC-3 cells were observed to be constitutively expressed in T cells, which may explain the relatively low Lipofection efficiencies observed with T cells (8%-21% GFP⁺). Indeed, overexpression of one CSG (IFI16) significantly decreased transfection efficiency in HEK-293T cells.

Approaches towards biomaterial-mediated gene editing for cancer immunotherapy

Gene therapies are transforming treatment modalities for many human diseases and disorders, including those in ophthalmology, oncology, and nephrology. To maximize the clinical efficacy and safety of these treatments, consideration of both delivery materials and cargos is critical. In consideration of the former, a large effort has been placed on transitioning away from potentially immunoreactive and toxic viral delivery mechanisms towards safer and highly tunable nonviral delivery mechanisms, including polymeric, lipid-based, and inorganic carriers. This change of paradigm does not come without obstacles, as efficient non-viral delivery is challenging, particularly to immune cells, and has yet to see clinical translation breakthroughs for gene editing. This mini-review describes notable examples of biomaterial-based gene delivery to immune cells, with emphasis on recent in vivo successes. In consideration of delivery cargos, clustered regularly interspaced palindromic repeat (CRISPR) technology is reviewed and its great promise in the field of immune cell gene editing is described. This mini-review describes how leading non-viral delivery materials and CRISPR technology can be integrated together to advance its clinical potential for therapeutic gene transfer to immune cells to treat cancer.

Improvement of mRNA Delivery Efficiency to a T Cell Line by Modulating PEG-Lipid Content and Phospholipid Components of Lipid Nanoparticles

(1) Background: T cells are important target cells, since they exert direct cytotoxic effects on infected/malignant cells, and affect the regulatory functions of other immune cells in a target antigen-specific manner. One of the current approaches for modifying the function of T cells is gene transfection by viral vectors. However, the insertion of the exogenous DNA molecules into the genome is attended by the risk of mutagenesis, especially when a transposon-based gene cassette is used. Based on this scenario, the transient expression of proteins by an in vitro-transcribed messenger RNA (IVT-mRNA) has become a subject of interest. The use of lipid nanoparticles (LNPs) for the transfection of IVT-mRNA is one of the more promising strategies for introducing exogenous genes. In this study, we report on the development of LNPs with transfection efficiencies that are comparable to that for electroporation in a T cell line (Jurkat cells). (2) Methods: Transfection efficiency was improved by optimizing the phospholipids and polyethylene glycol (PEG)-conjugated lipid components. (3) Results: Modification of the lipid composition resulted in the 221-fold increase in luciferase activity compared to a previously optimized formulation. Such a high transfection activity was due to the efficient uptake by clathrin/dynamin-dependent endocytosis and the relatively efficient escape into the cytoplasm at an early stage of endocytosis.

A novel non-viral delivery method that enables efficient engineering of primary human T cells for ex vivo cell therapy applications

Background aims

Next-generation immune cell therapy products will require complex modifications using engineering technologies that can maintain high levels of cell functionality. Non-viral engineering methods have the potential to address limitations associated with viral vectors. However, while electroporation is the most widely used non-viral modality, concerns about its effects on cell functionality have led to the exploration of alternative approaches. Here the authors have examined the suitability of the Solupore non-viral delivery system for engineering primary human T cells for cell therapy applications.

Methods

The Solupore system was used to deliver messenger RNA (mRNA) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) guide RNA ribonucleoprotein (RNP) cargos to T cells, and efficiency was measured by flow cytometry. Cell perturbation was assessed by immune gene expression profiling, including an electroporation comparator. In vitro and in vivo cytotoxicity of chimeric antigen receptor (CAR) T cells generated using the Solupore system was evaluated using a real-time cellular impedance assay and a Raji-luciferase mouse tumor model, respectively.

Results

Efficient transfection was demonstrated through delivery of mRNA and CRISPR CAS9 RNP cargos individually, simultaneously and sequentially using the Solupore system while consistently maintaining high levels of cell viability. Gene expression profiling revealed minimal alteration in immune gene expression, demonstrating the low level of perturbation experienced by the cells during this transfection process. By contrast, electroporation resulted in substantial changes in immune gene expression in T cells. CAR T cells generated using the Solupore system exhibited efficient cytotoxicity against target cancer cells in vitro and in vivo.

Conclusions

The Solupore system is a non-viral means of simply, rapidly and efficiently delivering cargos to primary human immune cells with retention of high cell viability and functionality.