Combinatorial design of ionizable lipid nanoparticles for muscle-selective mRNA delivery with minimized off-target effects

Injection site-retained lipid nanoparticles for targeted intramuscular delivery of mRNA RSV prefusion-F vaccine

mRNA therapeutics, particularly mRNA vaccines, hold significant promise for a wide range of medical applications. Lipid nanoparticles (LNPs) are the most clinically advanced delivery vehicles for mRNA, but issues such as off-target effects and liver accumulation hinder their broader clinical adoption. In this study, we designed and synthesized a library of 26 novel ionizable lipids to screen for better delivery efficiency and tissue specificity. After formulating into LNPs, these ionizable lipids exhibited favorable physicochemical properties. In vitro transfection and cytotoxicity assays revealed that LNPs formulated with YK-201, YK-202, and YK-209 showed superior transfection efficiency and low cytotoxicity. In a mouse model, intramuscular injection of Fluc mRNA-LNPs resulted in sustained and localized protein expression at the injection site. When applied to prepare RSV preF-mRNA vaccines, these novel LNPs elicited robust humoral immune responses and reduced lung damage, outperforming the clinically used SM-102. The safety of the LNP formulations was subsequently demonstrated in a mouse model. Collectively, these findings highlight the potential of these novel ionizable lipids as effective injection site-retained mRNA vaccine delivery vehicles.

Restoring hematopoietic stem and progenitor cell function in Fancc -/- mice by in situ delivery of RNA lipid nanoparticles

Fanconi anemia (FA) is a congenital multisystem disorder characterized by early-onset bone marrow failure (BMF) and cancer susceptibility. While ex vivo gene addition and repair therapies are being considered as treatment options, depleted hematopoietic stem cell (HSC) pools, poor HSC mobilization, compromised survival during ex vivo transduction, and increased sensitivity to conventional conditioning strategies limit eligibility for FA patients to receive gene therapies. As an alternative approach, we explored in vivo protein replacement by mRNA delivery via lipid nanoparticles (LNPs). Our study aims to address several key obstacles to current mRNA-LNP treatment: access to the HSC niche, effective expression half-life, and potential mRNA LNP immunogenicity. Results demonstrate efficient in vivo LNP transfection of murine BM via intravenous or intrafemoral injections, yielding reporter expression across hematopoietic and non-hematopoietic BM niche populations. Functionally, LNP delivery of modified Fancc mRNA restored ex vivo expansion. In a proof of principle approach, LNP-treated murine Fancc -/- HSPCs engrafted with restored alkylator resistance up to 120 h post-treatment using circularized mRNA constructs. In vitro delivery of mRNA LNPs resulted in modest differences in innate immune target gene expression in both FA and wild-type HSPCs. Our results suggest that mRNA-LNP-based protein replacement therapy holds promise for clinical translation.

Improving the Efficacy of Cancer mRNA Vaccines

mRNA vaccines consist of antigen-encoding mRNA, which produces the antigenic protein upon translation. Coupling antigen production with innate immune activation can generate a potent, antigen-specific T-cell response. Clinical reports have demonstrated the ability of mRNA vaccines to elicit an anticancer immune response against various tumor types. Here, we discuss strategies to enhance the potency of mRNA vaccines. We provide an overview of existing knowledge regarding the activation and trafficking mechanisms of mRNA vaccines and share optimization strategies to boost mRNA-mediated antigen production. In addition, we address methods to target mRNA vaccines to dendritic cells and lymph nodes, key initiators of the immune response. Finally, we review strategies for enhancing immune activation using adjuvants compatible with mRNA vaccines. mRNA vaccines offer unique advantages that can be utilized for oncology applications. However, significant work is needed to understand their underlying mechanisms and develop technologies to improve their effectiveness.

Developing mRNA Nanomedicines with Advanced Targeting Functions

The emerging messenger RNA (mRNA) nanomedicines have sprung up for disease treatment. Developing targeted mRNA nanomedicines has become a thrilling research hotspot in recent years, as they can be precisely delivered to specific organs or tissues to enhance efficiency and avoid side effects. Herein, we give a comprehensive review on the latest research progress of mRNA nanomedicines with targeting functions. mRNA and its carriers are first described in detail. Then, mechanisms of passive targeting, endogenous targeting, and active targeting are outlined, with a focus on various biological barriers that mRNA may encounter during in vivo delivery. Next, emphasis is placed on summarizing mRNA-based organ-targeting strategies. Lastly, the advantages and challenges of mRNA nanomedicines in clinical translation are mentioned. This review is expected to inspire researchers in this field and drive further development of mRNA targeting technology.

A Reverse Transcription Nucleic-Acid-Based Barcoding System for In Vivo Measurement of Lipid Nanoparticle mRNA Delivery

Lipid nanoparticles (LNPs) are the most extensively validated clinical delivery vehicles for mRNA therapeutics, exemplified by their widespread use in the mRNA COVID-19 vaccines. The pace of lipid nanoparticle (LNP) development for mRNA therapeutics is restricted by the limitations of existing methods for large-scale LNP screening. To address this challenge, we developed Quantitative Analysis of Reverse Transcribed Barcodes (QuART), a novel nucleic-acid-based system for measuring LNP functional delivery in vivo. QuART uses a bacterial retron reverse transcription system to couple functional mRNA delivery into the cytoplasm with a cDNA barcode readout. Our results demonstrate that QuART can be used to identify functional mRNA delivery both in vitro in cell culture and in vivo in mice. Multiplexing of QuART could enable high-throughput screening of LNP formulations, facilitating the rapid discovery of promising LNP candidates for mRNA therapeutics.

Cancer vaccines: current status and future directions

Cancer continues to be a major global health burden, with high morbidity and mortality. Building on the success of immune checkpoint inhibitors and adoptive cellular therapy, cancer vaccines have garnered significant interest, but their clinical success remains modest. Benefiting from advancements in technology, many meticulously designed cancer vaccines have shown promise, warranting further investigations to reach their full potential. Cancer vaccines hold unique benefits, particularly for patients resistant to other therapies, and they offer the ability to initiate broad and durable T cell responses. In this review, we highlight the antigen selection for cancer vaccines, introduce the immune responses induced by vaccines, and propose strategies to enhance vaccine immunogenicity. Furthermore, we summarize key features and notable clinical advances of various vaccine platforms. Lastly, we delve into the mechanisms of tumor resistance and explore the potential benefits of combining cancer vaccines with standard treatments and other immunomodulatory approaches to improve vaccine efficacy.

Corosolic acid derivative-based lipid nanoparticles for efficient RNA delivery

Lipid nanoparticles (LNPs) represent the most widely employed and clinically validated platform for in vivo RNA delivery. However, currently used LNP formulations, which consist of lipids and cholesterol, exhibit limited transfection efficiency and off-target hepatic transfection. These limitations necessitate higher dosage and pose potential safety concerns. In this study, three derivatives of corosolic acid (CA) were synthesized to create a library of cholesterol-free lipid nanoparticles, CAxLNPs. From this library, CAβLNP was identified as the most effective, exhibiting enhanced tumor cell uptake and superior endosomal membrane fusion capabilities compared to cholesterol-containing LNP formulations, leading to optimal endosomal escape and efficient cytoplasmic delivery of mRNA/siRNA. Following intratumoral injection, CAβLNP demonstrated significantly improved retention and penetration within tumor tissues while minimizing undesired hepatic transfection. This LNP formulation offers a safer, more effective carrier for RNA delivery, providing promising potential to expand the applications of RNA therapeutics.

Rational design and modular synthesis of biodegradable ionizable lipids via the Passerini reaction for mRNA delivery

The ionizable lipid component of lipid nanoparticle (LNP) formulations is essential for mRNA delivery by facilitating endosomal escape. Conventionally, these lipids are synthesized through complex, multistep chemical processes that are both time-consuming and require significant engineering. Furthermore, the development of new ionizable lipids is hindered by a limited understanding of the structure-activity relationships essential for effective mRNA delivery. In this work, we have developed a modular platform utilizing the Passerini reaction to rapidly generate large, chemically diverse libraries of biodegradable ionizable lipids. This high-throughput approach enables the systematic exploration of various lipid components-head groups, tails, and spacers-and their impacts on mRNA delivery efficiency. By investigating the hydrogen bonding potential between the lipid's head groups and the mRNA's ribose phosphate complex, we found that optimizing the methylene units between the lipid's head groups and linkages could enhance endosomal escape and, consequently, mRNA delivery efficiencies. Leveraging this insight, our platform has led to the identification of the biodegradable ionizable lipid A4B4-S3, which outperforms the current clinical benchmark, SM-102, in gene editing efficacy in mouse liver following systemic administration and demonstrates the promise for repeat-dose protein replacement treatments. This work not only offers a rapid, scalable method for ionizable lipid synthesis but also deepens our understanding of their structure-activity relationships, paving the way for more effective mRNA therapeutics.

mRNA lipid nanoparticle-incorporated nanofiber-hydrogel composite generates a local immunostimulatory niche for cancer immunotherapy

Hydrogel materials have emerged as versatile platforms for various biomedical applications. Notably, the engineered nanofiber-hydrogel composite (NHC) has proven effective in mimicking the soft tissue extracellular matrix, facilitating substantial recruitment of host immune cells and the formation of a local immunostimulatory microenvironment. Leveraging this feature, here we report an mRNA lipid nanoparticle (LNP)-incorporated NHC microgel matrix, termed LiNx, by incorporating LNPs loaded with mRNA encoding tumour antigens. Harnessing the potent transfection efficiency of LNPs in antigen-presenting cells (APCs), LiNx demonstrates remarkable immune cell recruitment, antigen expression and presentation, and cellular interaction. These attributes collectively create an immunostimulating milieu and yield a potent immune response achievable with a single dose, comparable to the conventional three-dose LNP immunization regimen. Further investigations reveal that the LiNx not only generates heightened Th1 and Th2 responses but also elicits a distinctive Type 17 T helper cell-mediated response pivotal for bolstering antitumour efficacy. Our findings elucidate the mechanism underlying LiNx's role in potentiating antigen-specific immune responses, presenting a new strategy for cancer immunotherapy.

Advances in nucleic acid-based cancer vaccines

Nucleic acid vaccines have emerged as crucial advancements in vaccine technology, particularly highlighted by the global response to the COVID-19 pandemic. The widespread administration of mRNA vaccines against COVID-19 to billions globally marks a significant milestone. Furthermore, the approval of an mRNA vaccine for Respiratory Syncytial Virus (RSV) this year underscores the versatility of this technology. In oncology, the combination of mRNA vaccine encoding neoantigens and immune checkpoint inhibitors (ICIs) has shown remarkable efficacy in eliciting protective responses against diseases like melanoma and pancreatic cancer. Although the use of a COVID-19 DNA vaccine has been limited to India, the inherent stability at room temperature and cost-effectiveness of DNA vaccines present a viable option that could benefit developing countries. These advantages may help DNA vaccines address some of the challenges associated with mRNA vaccines. Currently, several trials are exploring the use of DNA-encoded neoantigens in combination with ICIs across various cancer types. These studies highlight the promising role of nucleic acid-based vaccines as the next generation of immunotherapeutic agents in cancer treatment. This review will delve into the recent advancements and current developmental status of both mRNA and DNA-based cancer vaccines.

Calculating Apparent pKa Values of Ionizable Lipids in Lipid Nanoparticles

Creating new ionizable lipids for use in lipid nanoparticles (LNPs) is an active field of research. One of the critical properties for selecting suitable ionizable lipids is the apparent pKa value of the lipid as formulated in an LNP. We have developed a structure-based, computational methodology for the prediction of the apparent pKa value of ionizable lipids within LNPs and have tested it using the lipid formulations in the mRNA LNP COVID-19 vaccines COMIRNATY and Spikevax, and the siRNA LNP therapeutic Onpattro. The calculation was also applied to Lipid A, a variant of the ionizable lipid used in COMIRNATY.

From Sequence to System: Enhancing IVT mRNA Vaccine Effectiveness through Cutting-Edge Technologies

The COVID-19 pandemic has spotlighted the potential of in vitro transcribed (IVT) mRNA vaccines with their demonstrated efficacy, safety, cost-effectiveness, and rapid manufacturing. Numerous IVT mRNA vaccines are now under clinical trials for a range of targets, including infectious diseases, cancers, and genetic disorders. Despite their promise, IVT mRNA vaccines face hurdles such as limited expression levels, nonspecific targeting beyond the liver, rapid degradation, and unintended immune activation. Overcoming these challenges is crucial to harnessing the full therapeutic potential of IVT mRNA vaccines for global health advancement. This review provides a comprehensive overview of the latest research progress and optimization strategies for IVT mRNA molecules and delivery systems, including the application of artificial intelligence (AI) models and deep learning techniques for IVT mRNA structure optimization and mRNA delivery formulation design. We also discuss recent development of the delivery platforms, such as lipid nanoparticles (LNPs), polymers, and exosomes, which aim to address challenges related to IVT mRNA protection, cellular uptake, and targeted delivery. Lastly, we offer insights into future directions for improving IVT mRNA vaccines, with the hope to spur further progress in IVT mRNA vaccine research and development.

Nonviral targeted mRNA delivery: principles, progresses, and challenges

Messenger RNA (mRNA) therapeutics have garnered considerable attention due to their remarkable efficacy in the treatment of various diseases. The COVID-19 mRNA vaccine and RSV mRNA vaccine have been approved on the market. Due to the inherent nuclease-instability and negative charge of mRNA, delivery systems are developed to protect the mRNA from degradation and facilitate its crossing cell membrane to express functional proteins or peptides in the cytoplasm. However, the deficiency in transfection efficiency and targeted biological distribution are still the major challenges for the mRNA delivery systems. In this review, we first described the physiological barriers in the process of mRNA delivery and then discussed the design approach and recent advances in mRNA delivery systems with an emphasis on their tissue/cell-targeted abilities. Finally, we pointed out the existing challenges and future directions with deep insights into the design of efficient mRNA delivery systems. We believe that a high-precision targeted delivery system can greatly improve the therapeutic effects and bio-safety of mRNA therapeutics and accelerate their clinical transformations. This review may provide a new direction for the design of mRNA delivery systems and serve as a useful guide for researchers who are looking for a suitable mRNA delivery system.

Single-stranded DNA with internal base modifications mediates highly efficient knock-in in primary cells using CRISPR-Cas9

Single-stranded DNA (ssDNA) templates along with Cas9 have been used for knocking-in exogenous sequences in the genome but suffer from low efficiency. Here, we show that ssDNA with chemical modifications in 12-19% of internal bases, which we denote as enhanced ssDNA (esDNA), improve knock-in (KI) by 2-3-fold compared to end-modified ssDNA in airway basal stem cells (ABCs), CD34 + hematopoietic cells (CD34 + cells), T-cells and endothelial cells. Over 50% of alleles showed KI in three clinically relevant loci (CFTR, HBB and CCR5) in ABCs using esDNA and up to 70% of alleles showed KI in the HBB locus in CD34 + cells in the presence of a DNA-PKcs inhibitor. This level of correction is therapeutically relevant and is comparable to adeno-associated virus-based templates. The esDNA templates did not improve KI in induced pluripotent stem cells (iPSCs). This may be due to the absence of the nuclease TREX1 in iPSCs. Indeed, knocking out TREX1 in other cells improved KI using unmodified ssDNA. esDNA can be used to modify 20-30 bp regions in primary cells for therapeutic applications and biological modeling. The use of this approach for gene length insertions will require new methods to produce long chemically modified ssDNA in scalable quantities.

Effect of Lipid Nanoparticle Physico-Chemical Properties and Composition on Their Interaction with the Immune System

Lipid nanoparticles (LNPs) have shown promise as a delivery system for nucleic acid-based therapeutics, including DNA, siRNA, and mRNA vaccines. The immune system plays a critical role in the response to these nanocarriers, with innate immune cells initiating an early response and adaptive immune cells mediating a more specific reaction, sometimes leading to potential adverse effects. Recent studies have shown that the innate immune response to LNPs is mediated by Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs), which recognize the lipid components of the nanoparticles. This recognition can trigger the activation of inflammatory pathways and the production of cytokines and chemokines, leading to potential adverse effects such as fever, inflammation, and pain at the injection site. On the other hand, the adaptive immune response to LNPs appears to be primarily directed against the protein encoded by the mRNA cargo, with little evidence of an ongoing adaptive immune response to the components of the LNP itself. Understanding the relationship between LNPs and the immune system is critical for the development of safe and effective nucleic acid-based delivery systems. In fact, targeting the immune system is essential to develop effective vaccines, as well as therapies against cancer or infections. There is a lack of research in the literature that has systematically studied the factors that influence the interaction between LNPs and the immune system and further research is needed to better elucidate the mechanisms underlying the immune response to LNPs. In this review, we discuss LNPs' composition, physico-chemical properties, such as size, shape, and surface charge, and the protein corona formation which can affect the reactivity of the immune system, thus providing a guide for the research on new formulations that could gain a favorable efficacy/safety profile.

High-throughput synthesis and optimization of ionizable lipids through A3 coupling for efficient mRNA delivery

BACKGROUND

The efficacy of mRNA-based vaccines and therapies relies on lipid nanoparticles (LNPs) as carriers to deliver mRNA into cells. The chemical structure of ionizable lipids (ILs) within LNPs is crucial in determining their delivery efficiency.

RESULTS

In this study, we synthesized 623 alkyne-bearing ionizable lipids using the A3 coupling reaction and assessed their effectiveness in mRNA delivery. ILs with specific structural features-18-carbon alkyl chains, a cis-double bond, and ethanolamine head groups-demonstrated superior mRNA delivery capabilities. Variations in saturation, double bond placement, and chain length correlated with decreased efficacy. Alkynes positioned adjacent to nitrogen atoms in ILs reduced the acid dissociation constant (pKa) of LNPs, thereby hindering mRNA delivery efficiency. Conversion of alkynes to alkanes significantly enhanced mRNA delivery of ILs both in vitro and in vivo. Moreover, combining optimized ILs with cKK-E12 yields synergistic LNPs that showed markedly augmented mRNA expression levels in vivo.

CONCLUSIONS

Overall, our study provides insights into the structure-function relationships of ILs, providing a foundation for the rational design of ILs to enhance the efficacy of LNPs in mRNA delivery.

Tuning Lipid Nanoparticles for RNA Delivery to Extrahepatic Organs

RNA therapeutics have been successfully transitioned into clinical applications. Lipid nanoparticles (LNPs) are widely employed as nonviral delivery vehicles for RNA therapeutics in commercial vaccine and gene therapy products. However, the bottleneck in expanding the clinical applications of LNP-based RNA therapeutics lies in the tendency of these nanoparticles to preferentially accumulate in the liver. This challenge underscores the need to design LNPs capable of delivering RNA to organs beyond the liver. In this perspective, recent progress is discussed in developing strategies for designing LNPs to deliver RNA to extrahepatic organs. Organ-selective targeting capability is achieved by either altering the composition of the LNP formulation or chemically modifying the ionizable lipid component. Both approaches result in changes in the physicochemical properties of the LNPs, which subsequently alters the composition of the biomolecular corona that adsorbs onto its surface following administration. The biomolecular corona is a known mechanism that mediates organ-selective LNP delivery. Furthermore, this perspective aims to provide an outlook on shaping the next-generation LNP delivery platforms. Potential efforts include targeting specific cell types, improving the safety profile of LNPs, and developing strategies to overcome physiological barriers against organ-specific delivery.

Targeted Therapy of Osteoarthritis via Intra-Articular Delivery of Lipid-Nanoparticle-Encapsulated Recombinant Human FGF18 mRNA

Fibroblast growth factor 18 (FGF18) emerges as a promising therapeutic target for osteoarthritis (OA). In this study, a novel articular cavity-localized lipid nanoparticle (LNP) named WG-PL14 is developed. This optimized formulation has a nearly 30-fold increase in mRNA expression as well as better articular cavity enrichment compared to commercial lipids MC3 when performing intra-articular injection. Then, a mRNA sequence encoding recombinant human FGF18 (rhFGF18) for potential mRNA therapy in OA is optimized. In vitro assays confirm the translation of rhFGF18 mRNA into functional proteins within rat and human chondrocytes, promoting cell proliferation and extracellular matrix (ECM) synthesis. Subsequently, the therapeutic efficacy of the LNP-rhFGF18 mRNA complex is systematically assessed in a mouse OA model. The administration exhibits several positive outcomes, including an improved pain response, upregulation of ECM-related genes (e.g., AGRN and HAS2), and remodeling of subchondral bone homeostasis compared to a control group. Taken together, these findings underscore the potential of localized LNP-rhFGF18 mRNA therapy in promoting the regeneration of cartilage tissue and mitigating the progression of OA.

In Vivo Endothelial Cell Gene Silencing by siRNA-LNPs Tuned with Lipoamino Bundle Chemical and Ligand Targeting

Although small-interfering RNAs (siRNAs) are specific silencers for numerous disease-related genes, their clinical applications still require safe and effective means of delivery into target cells. Highly efficient lipid nanoparticles (LNPs) are developed for siRNA delivery, showcasing the advantages of novel pH-responsive lipoamino xenopeptide (XP) carriers. These sequence-defined XPs are assembled by branched lysine linkages between cationizable polar succinoyl tetraethylene pentamine (Stp) units and apolar lipoamino fatty acids (LAFs) at various ratios into bundle or U-shape topologies. Formulation of siRNA-LNPs using LAF4-Stp1 XPs as ionizable compounds led to robust cellular uptake, high endosomal escape, and successful in vitro gene silencing activity at an extremely low (150 picogram) siRNA dose. Of significance is the functional in vivo endothelium tropism of siRNA-LNPs with bundle LAF4-Stp1 XP after intravenous injection into mice, demonstrated by superior knockdown of liver sinusoidal endothelial cell (LSEC)-derived factor VIII (FVIII) and moderate silencing of hepatocyte-derived FVII compared to DLin-MC3-DMA-based LNPs. Optimizing lipid composition following click-modification of siRNA-LNPs with ligand c(RGDfK) efficiently silenced vascular endothelial growth factor receptor-2 (VEGFR-2) in tumor endothelial cells (TECs). The findings shed light on the role of ionizable XPs in the LNP in vivo cell-type functional targeting, laying the groundwork for future therapeutic applications.

Advances in the development of lipid nanoparticles for ophthalmic therapeutics

Previously, researchers have employed Lipid nanoparticles (LNPs) to directly encapsulate medicines. In the realm of gene therapy, researchers have begun to employ lipid nanoparticles to encapsulate nucleic acids such as messenger RNA, small interfering RNA, and plasmid DNA, which are known as nucleic acid lipid nanoparticles. Recent breakthroughs in LNP-based medicine have provided significant prospects for the treatment of ocular disorders, such as corneal, choroidal, and retinal diseases. The use of LNP as a delivery mechanism for medicines and therapeutic genes can increase their effectiveness while avoiding undesired immune reactions. However, LNP-based medicines may pose ocular concerns. In this review, we discuss the general framework of LNP. Additionally, we review adjustable approaches and evaluate their possible risks. In addition, we examine newly described ocular illnesses in which LNP was utilized as a delivery mechanism. Finally, we provide perspectives for solving these potential issues.

Engineering CaP-Pickering emulsion for enhanced mRNA cancer vaccines via dual DC and NK activations

mRNA delivery systems, such as lipid nanoparticle (LNP), have made remarkable strides in improving mRNA expression, whereas immune system activation operates on a threshold. Maintaining a delicate balance between antigen expression and dendritic cell (DC) activation is vital for effective immune recognition. Here, a water-in-oil-in-water (w/o/w) Pickering emulsion stabilized with calcium phosphate nanoparticles (CaP-PME) is developed for mRNA delivery in cancer vaccination. CaP-PME efficiently transports mRNA into the cytoplasm, induces pro-inflammatory responses and activates DCs by disrupting intracellular calcium/potassium ions balance. Unlike LNP, CaP-PME demonstrates a preference for DCs, enhancing their activation and migration to lymph nodes. It elicits interferon-γ-mediated CD8+ T cell responses and promotes NK cell proliferation and activation, leading to evident NK cells infiltration and ameliorated tumor microenvironment. The prepared w/o/w Pickering emulsion demonstrates superior anti-tumor effects in E.G7 and B16-OVA tumor models, offering promising prospects as an enhanced mRNA delivery vehicle for cancer vaccinations.

Chemical Design Strategy of Ionizable Lipids for In Vivo mRNA Delivery

Lipid nanoparticles (LNPs) are the most clinically successful drug delivery systems that have accelerated the development of mRNA drugs and vaccines. Among various structural components of LNPs, more recent attention has been paid in ionizable lipids (ILs) that was supposed as the key component in determining the effectiveness of LNPs for in vivo mRNA delivery. ILs are typically comprised of three moieties including ionizable heads, linkers, and hydrophobic tails, which suggested that the combination of different functional groups in three moieties could produce ILs with diverse chemical structures and biological identities. In this concept article, we provide a summary of chemical design strategy for high-performing IL candidates and discuss their structure-activity relationships for shifting tissue-selective mRNA delivery. We also propose an outlook for the development of next-generation ILs, enabling the broader translation of mRNA formulated with LNPs.

Lipid nanoparticle (LNP) mediated mRNA delivery in cardiovascular diseases: Advances in genome editing and CAR T cell therapy

Cardiovascular diseases (CVDs) are the leading cause of global mortality among non-communicable diseases. Current cardiac regeneration treatments have limitations and may lead to adverse reactions. Hence, innovative technologies are needed to address these shortcomings. Messenger RNA (mRNA) emerges as a promising therapeutic agent due to its versatility in encoding therapeutic proteins and targeting "undruggable" conditions. It offers low toxicity, high transfection efficiency, and controlled protein production without genome insertion or mutagenesis risk. However, mRNA faces challenges such as immunogenicity, instability, and difficulty in cellular entry and endosomal escape, hindering its clinical application. To overcome these hurdles, lipid nanoparticles (LNPs), notably used in COVID-19 vaccines, have a great potential to deliver mRNA therapeutics for CVDs. This review highlights recent progress in mRNA-LNP therapies for CVDs, including Myocardial Infarction (MI), Heart Failure (HF), and hypercholesterolemia. In addition, LNP-mediated mRNA delivery for CAR T-cell therapy and CRISPR/Cas genome editing in CVDs and the related clinical trials are explored. To enhance the efficiency, safety, and clinical translation of mRNA-LNPs, advanced technologies like artificial intelligence (AGILE platform) in RNA structure design, and optimization of LNP formulation could be integrated. We conclude that the strategies to facilitate the extra-hepatic delivery and targeted organ tropism of mRNA-LNPs (SORT, ASSET, SMRT, and barcoded LNPs) hold great prospects to accelerate the development and translation of mRNA-LNPs in CVD treatment.

Viral and Non-Viral Systems to Deliver Gene Therapeutics to Clinical Targets

Clustered regularly interspersed short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology has revolutionized the field of gene therapy as it has enabled precise genome editing with unprecedented accuracy and efficiency, paving the way for clinical applications to treat otherwise incurable genetic disorders. Typically, precise genome editing requires the delivery of multiple components to the target cells that, depending on the editing platform used, may include messenger RNA (mRNA), protein complexes, and DNA fragments. For clinical purposes, these have to be efficiently delivered into transplantable cells, such as primary T lymphocytes or hematopoietic stem and progenitor cells that are typically sensitive to exogenous substances. This challenge has limited the broad applicability of precise gene therapy applications to those strategies for which efficient delivery methods are available. Electroporation-based methodologies have been generally applied for gene editing applications, but procedure-associated toxicity has represented a major burden. With the advent of novel and less disruptive methodologies to deliver genetic cargo to transplantable cells, it is now possible to safely and efficiently deliver multiple components for precise genome editing, thus expanding the applicability of these strategies. In this review, we describe the different delivery systems available for genome editing components, including viral and non-viral systems, highlighting their advantages, limitations, and recent clinical applications. Recent improvements to these delivery methods to achieve cell specificity represent a critical development that may enable in vivo targeting in the future and will certainly play a pivotal role in the gene therapy field.

Accelerating ionizable lipid discovery for mRNA delivery using machine learning and combinatorial chemistry

To unlock the full promise of messenger (mRNA) therapies, expanding the toolkit of lipid nanoparticles is paramount. However, a pivotal component of lipid nanoparticle development that remains a bottleneck is identifying new ionizable lipids. Here we describe an accelerated approach to discovering effective ionizable lipids for mRNA delivery that combines machine learning with advanced combinatorial chemistry tools. Starting from a simple four-component reaction platform, we create a chemically diverse library of 584 ionizable lipids. We screen the mRNA transfection potencies of lipid nanoparticles containing those lipids and use the data as a foundational dataset for training various machine learning models. We choose the best-performing model to probe an expansive virtual library of 40,000 lipids, synthesizing and experimentally evaluating the top 16 lipids flagged. We identify lipid 119-23, which outperforms established benchmark lipids in transfecting muscle and immune cells in several tissues. This approach facilitates the creation and evaluation of versatile ionizable lipid libraries, advancing the formulation of lipid nanoparticles for precise mRNA delivery.

Leveraging high-throughput screening technologies in targeted mRNA delivery

Messenger ribonucleic acid (mRNA) has emerged as a promising molecular preventive and therapeutic approach that opens new avenues for healthcare. Although the use of delivery systems, especially lipid nanoparticles (LNPs), greatly improves the efficiency and stability of mRNA, mRNA tends to accumulate in the liver and hardly penetrates physiological barriers to reach the target site after intravenous injection. Hence, the rational design of targeting strategies aimed at directing mRNA to specific tissues and cells remains an enormous challenge in mRNA therapy. High-throughput screening (HTS) is a cutting-edge targeted technique capable of synthesizing chemical compound libraries for the large-scale experiments to validate the efficiency of mRNA delivery system. In this review, we firstly provide an overview of conventional low-throughput targeting strategies. Then the latest advancements in HTS techniques for mRNA targeted delivery, encompassing optimizing structures of large-scale delivery vehicles and developing large-scale surface ligands, as well as the applications of HTS techniques in extrahepatic systemic diseases are comprehensively summarized. Moreover, we illustrate the selection of administration routes for targeted mRNA delivery. Finally, challenges in the field and potential solutions to tackle them are proposed, offering insights for future development toward mRNA targeted therapy.

The impact of, and expectations for, lipid nanoparticle technology: From cellular targeting to organelle targeting

The success of mRNA vaccines against COVID-19 has enhanced the potential of lipid nanoparticles (LNPs) as a system for the delivery of mRNA. In this review, we describe our progress using a lipid library to engineer ionizable lipids and promote LNP technology from the viewpoints of safety, controlled biodistribution, and mRNA vaccines. These advancements in LNP technology are applied to cancer immunology, and a potential nano-DDS is constructed to evaluate immune status that is associated with a cancer-immunity cycle that includes the sub-cycles in tumor microenvironments. We also discuss the importance of the delivery of antigens and adjuvants in enhancing the cancer-immunity cycle. Recent progress in NK cell targeting in cancer immunotherapy is also introduced. Finally, the impact of next-generation DDS technology is explained using the MITO-Porter membrane fusion-based delivery system for the organelle targeting of the mitochondria. We introduce a successful example of the MITO-Porter used in a cell therapeutic strategy to treat cardiomyopathy.

The dawn of a new Era: mRNA vaccines in colorectal cancer immunotherapy

Colorectal cancer (CRC) is a typical cancer that accounts for 10% of all new cancer cases annually and nearly 10% of all cancer deaths. Despite significant progress in current classical interventions for CRC, these traditional strategies could be invasive and with numerous adverse effects. The poor prognosis of CRC patients highlights the evident and pressing need for more efficient and targeted treatment. Novel strategies regarding mRNA vaccines for anti-tumor therapy have also been well-developed since the successful application for the prevention of COVID-19. mRNA vaccine technology won the 2023 Nobel Prize in Physiology or Medicine, signaling a new direction in human anti-cancer treatment: mRNA medicine. As a promising new immunotherapy in CRC and other multiple cancer treatments, the mRNA vaccine has higher specificity, better efficacy, and fewer side effects than traditional strategies. The present review outlines the basics of mRNA vaccines and their advantages over other vaccines and informs an available strategy for developing efficient mRNA vaccines for CRC precise treatment. In the future, more exploration of mRNA vaccines for CRC shall be attached, fostering innovation to address existing limitations.

Advances in lipid nanoparticle mRNA therapeutics beyond COVID-19 vaccines

The remarkable success of two lipid nanoparticle-mRNA vaccines against coronavirus disease (COVID-19) has placed the therapeutic and prophylactic potential of messenger RNA (mRNA) in the spotlight. It has also drawn attention to the indispensable role of lipid nanoparticles in enabling the effects of this nucleic acid. To date, lipid nanoparticles are the most clinically advanced non-viral platforms for mRNA delivery. This is thanks to their favorable safety profile and efficiency in protecting the nucleic acid from degradation and allowing its cellular uptake and cytoplasmic release upon endosomal escape. Moreover, the development of lipid nanoparticle-mRNA therapeutics was already a very active area of research even before the COVID-19 pandemic, which has likely only begun to bear its fruits. In this Review, we first discuss key aspects of the development of lipid nanoparticles as mRNA carriers. We then highlight promising preclinical and clinical studies involving lipid nanoparticle-mRNA formulations against infectious diseases and cancer, and to enable protein replacement or supplementation and genome editing. Finally, we elaborate on the challenges in advancing lipid nanoparticle-mRNA technology to widespread therapeutic use.

Single-Stranded DNA with Internal Base Modifications Mediates Highly Efficient Gene Insertion in Primary Cells

Single-stranded DNA (ssDNA) templates along with Cas9 have been used for gene insertion but suffer from low efficiency. Here, we show that ssDNA with chemical modifications in 10-17% of internal bases (eDNA) is compatible with the homologous recombination machinery. Moreover, eDNA templates improve gene insertion by 2-3 fold compared to unmodified and end-modified ssDNA in airway basal stem cells (ABCs), hematopoietic stem and progenitor cells (HSPCs), T-cells and endothelial cells. Over 50% of alleles showed gene insertion in three clinically relevant loci (CFTR, HBB, and CCR5) in ABCs using eDNA and up to 70% of alleles showed gene insertion in the HBB locus in HSPCs. This level of correction is therapeutically relevant and is comparable to adeno-associated virus-based templates. Knocking out TREX1 nuclease improved gene insertion using unmodified ssDNA but not eDNA suggesting that chemical modifications inhibit TREX1. This approach can be used for therapeutic applications and biological modeling.

Can the Revolution in mRNA-Based Vaccine Technologies Solve the Intractable Health Issues of Current Ruminant Production Systems?

To achieve the World Health Organization's global Sustainable Development Goals, increased production of high-quality protein for human consumption is required while minimizing, ideally reducing, environmental impacts. One way to achieve these goals is to address losses within current livestock production systems. Infectious diseases are key limiters of edible protein production, affecting both quantity and quality. In addition, some of these diseases are zoonotic threats and potential contributors to the emergence of antimicrobial resistance. Vaccination has proven to be highly successful in controlling and even eliminating several livestock diseases of economic importance. However, many livestock diseases, both existing and emerging, have proven to be recalcitrant targets for conventional vaccination technologies. The threat posed by the COVID-19 pandemic resulted in unprecedented global investment in vaccine technologies to accelerate the development of safe and efficacious vaccines. While several vaccination platforms emerged as front runners to meet this challenge, the clear winner is mRNA-based vaccination. The challenge now is for livestock industries and relevant stakeholders to harness these rapid advances in vaccination to address key diseases affecting livestock production. This review examines the key features of mRNA vaccines, as this technology has the potential to control infectious diseases of importance to livestock production that have proven otherwise difficult to control using conventional approaches. This review focuses on the challenging diseases of ruminants due to their importance in global protein production. Overall, the current literature suggests that, while mRNA vaccines have the potential to address challenges in veterinary medicine, further developments are likely to be required for this promise to be realized for ruminant and other livestock species.