mRNA-based therapeutics--developing a new class of drugs

Ionizable Lipids with Branched Linkers Enhance the Delivery of mRNA Vaccines

The emergence of mRNA vaccines has heralded an epoch in disease prevention and treatment. Safe and efficient mRNA delivery systems are highly desired for the widespread application of mRNA therapeutics. Herein, we have designed a facile synthetic pathway for producing ionizable lipids featuring various branched linkers. These lipids have been integrated into lipid nanoparticles (LNPs) to improve the delivery of mRNA vaccines. The influence of linker structure on lipids and LNPs is currently underreported, yet it undeniably exerts a substantial impact on the outcomes. Through systematic screening and formulation optimization, we have identified that LNPs comprising ionizable lipids with a branched β-isobutylglutarate linker (bLNPs) exhibited superior transfection capabilities. In preclinical cancer prevention and treatment models, mRNA vaccines delivered by bLNPs (mRNA-bLNPs) have shown significant efficacy without causing systemic toxicity, highlighting the potential of bLNPs for clinical translation. Our synthetic strategy facilitates the expansion of the LNP library and provides valuable insights into the relationship between linker structures and delivery efficiency, thereby propelling the advancement of LNP technology.

Apolipoprotein Fusion Enables Spontaneous Functionalization of mRNA Lipid Nanoparticles with Antibody for Targeted Cancer Therapy

The mRNA-lipid nanoparticles (mRNA@LNPs) offer a novel opportunity to treat targets previously considered undruggable. Although antibody conjugation is crucial for enhancing the specificity, delivery efficiency, and minimizing the toxicity of mRNA therapeutics, current chemical conjugation methods are complex and produce heterogeneous particles with misoriented antibodies. In this work, we introduce a chemical-free approach to functionalize mRNA@LNPs with antibodies, mimicking protein corona formation for targeted mRNA delivery. By fusing apolipoprotein to the Fc domain of a targeting antibody, we enabled the antibody to spontaneously display on the surface of mRNA@LNPs without altering the existing LNP process or employing complex chemical conjugation techniques. We demonstrated precise protein expression using trastuzumab-bound mRNA@LNPs, facilitating specific mRNA expression in HER2-positive cancer cells. mRNA was efficiently delivered to the tumor site after intravenous administration. While the control LNPs lacking targeting antibodies caused acute liver toxicity, trastuzumab-displayed LNPs showed no systemic toxicity. The tumor-specific delivery of p53 tumor suppressor mRNA led to the complete regression of cancer cells. Thus, apolipoprotein fusion enables a straightforward and scalable production of antibody-functionalized mRNA@LNPs, offering significant therapeutic potential in gene therapy.

Intraperitoneal administration of mRNA encoding interleukin-12 for immunotherapy in peritoneal carcinomatosis

Peritoneal carcinomatosis is an advanced stage of cancer with very limited treatment options. Locoregional immunotherapy is being evaluated as a way to improve efficacy and limit toxicity. This study assessed the efficacy of a cationic polymer/lipid-based transfection compound in delivering mRNA molecules intraperitoneally. Our investigation of the transfer of luciferase mRNA in murine models of peritoneal carcinomatosis revealed preferential luciferase expression in the omentum upon the intraperitoneal administration of complexed mRNAs. Macrophages were identified as key cells that capture and express the mRNA complexes, and accordingly, depletion of resident macrophages led to reduced reporter luciferase expression. To explore the therapeutic potential of this approach, mRNA complexes encoding single-chain interleukin-12 (IL12), an immunostimulatory molecule (mRNA-IL12), were investigated. mRNA-IL12-treated mice exhibited a significant survival advantage in models of peritoneal carcinomatosis and acquired immune memory, as shown upon subcutaneous rechallenge. Tumor microenvironment analyses revealed increased numbers of CD4+ and CD8+ T cells with a more proliferative phenotype, accompanied by decreased myeloid populations in the omentum. Overall, our study underscores the potential of mRNA complexes for efficient mRNA delivery, eliciting effective antitumor responses and modulating the tumor microenvironment to treat peritoneal carcinomatosis.

Hyaluronic acid coating of poly(β-amino ester)/mRNA polyplexes enables ultra-high transfection efficiency

mRNA holds significant potential for a wide range of biomedical applications, efficient and safe delivery of mRNA into target cells is essential to realize its therapeutic benefits. Linear poly(β-amino ester)s (LPAEs) have been utilized for mRNA delivery, yet there is a need to enhance their transfection efficiency and safety profile. In this study, a novel LPAE-based ternary mRNA delivery system with ultra-high transfection efficiency is developed by coating hyaluronic acid (HA) onto LPAE/mRNA binary polyplexes. Results demonstrate that across a broad range of HA doses, mRNA transfection and cell viability can be significantly enhanced. Intriguingly, pre-treating cells with HA further boosts the transfection efficiency up to 99.2 %. Mechanistic studies reveal that HA coating impacts the size, Zeta potential of the binary polyplexes, enhancing their interaction with the cell membrane and facilitating cellular uptake. Leveraging the unique biocompatibility and biodegradability of HA, this ternary mRNA delivery system emerges as a promising option for practical applications. The approach of coating binary polyplexes with natural biomacromolecules can be extended to other non-viral mRNA delivery vectors to achieve superior transfection efficiency and safety profiles.

Incorporation of ionizable lipids into the outer shell of lipid-coated calcium phosphate nanoparticles boosts cellular mRNA delivery

Messenger RNA is a highly promising biotherapeutic modality with great potential in preventive and therapeutic vaccination, and in the modulation of cellular function through transient expression of therapeutic proteins. However, for cellular delivery, mRNA requires packaging into delivery vehicles that mediate uptake and also shield the mRNA against degradation. Lipid-coated calcium phosphate (LCP) nanoparticles encapsulate the mRNA in a calcium phosphate core, which is coated by a bilayer of structural lipids, positively charged lipids and pegylated lipid to mediate cellular uptake and achieve colloidal stabilization. Here, we show that such nanoparticles using positively charged lipids achieve cellular uptake but only poor cytosolic mRNA delivery. However, mRNA release could be greatly enhanced through incorporation of ionizable lipids into the outer leaflet of the lipid bilayer. We optimized the composition and molar ratios of ionizable lipids, positive lipid, cholesterol, and polyethylene glycol (PEG) and evaluated the potency of the formulations for the cellular delivery of mRNA. Whereas in lipid nanoparticles, the ionizable lipid has a main role in the complexation of the mRNA, our study provides a new paradigm for the employment of ionizable cationic lipids in nanocarriers other than lipid nanoparticles (LNPs) to boost the endosomal release of nucleic acids.

New approach methodologies to assess wanted and unwanted drugs-induced immunostimulation

This review examines various classes of drugs, focusing on their therapeutic and adverse effects, particularly in relation to immunostimulation. We emphasize the potential of new approach methodologies (NAMs) to study both expected and unexpected immunostimulatory effects. By evaluating the modes of action of different immunostimulatory drugs, we aim to provide insights into effectively assessing unwanted immunostimulatory responses. The review begins by exploring drugs that stimulate the immune system-including immunostimulants, monoclonal antibodies, chemotherapeutics, and nucleic acid-based drugs-to outline NAMs that could be employed to evaluate immunostimulation.

Clinical advancements in mRNA vaccines against viral infections

Over the last decade, mRNA vaccines development has shown significant advancement, particularly during the COVID-19 pandemic. This comprehensive review examines the efficacy of pivotal vaccines against emerging COVID-19 variants and strategies for enhancing vaccine effectiveness. It also explores the versatility of mRNA technology in addressing other infectious diseases such as influenza, respiratory syncytial virus, HIV, cytomegalovirus, Ebola, Zika, Rabies, and Nipah viruses. The analysis includes safety and clinical progress of mRNA vaccines and evaluates their potential in combination vaccine strategies. Additionally, it addresses challenges related to delivery and scalability while highlighting opportunities for future advancements in the field. Recent advances in mRNA optimization, biomaterial-based delivery and thermostable designs offer promising solutions. It is essential to gain insights into the evolving landscape of mRNA vaccine technology to maximize its vital role in addressing diverse viral threats, advancing vaccinology and enhancing public health preparedness for future pandemic.

Branched chemically modified poly(A) tails enhance the translation capacity of mRNA

Although messenger RNA (mRNA) has proved effective as a vaccine, its potential as a general therapeutic modality is limited by its instability and low translation capacity. To increase the duration and level of protein expression from mRNA, we designed and synthesized topologically and chemically modified mRNAs with multiple synthetic poly(A) tails. Here we demonstrate that the optimized multitailed mRNA yielded ~4.7-19.5-fold higher luminescence signals than the control mRNA from 24 to 72 h post transfection in cellulo and 14 days detectable signal versus <7 days signal from the control in vivo. We further achieve efficient multiplexed genome editing of the clinically relevant genes Pcsk9 and Angptl3 in mouse liver at a minimal mRNA dosage. Taken together, these results provide a generalizable approach to synthesize capped branched mRNA with markedly enhanced translation capacity.

Effective mRNA transfection of tumor cells using cationic triacyl lipid‑based mRNA lipoplexes

Previously, it was reported that mRNA/cationic liposome complexes (mRNA lipoplexes) composed of the cationic triacyl lipid, 11-((1,3-bis(dodecanoyloxy)-2-((dodecanoyloxy)methyl)propan-2-yl)amino)-N,N,N- trimethyl-11-oxoundecan-1-aminium bromide (TC-1-12), with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine and poly(ethylene glycol) cholesteryl ether, induce high protein expression in human cervical carcinoma HeLa cells. In the present study, the authors aimed to optimize mRNA transfection using TC-1-12-based mRNA lipoplexes. mRNA lipoplexes were prepared at various charge ratios (+:-) using modified ethanol injection (MEI) and thin-film hydration (TFH) methods and compared the protein expression efficiency after transfection of HeLa cells with the developed mRNA lipoplexes. Firefly luciferase (FLuc) and enhanced green fluorescent protein (EGFP) mRNA lipoplexes prepared using the MEI method exhibited higher Luc and EGFP expression levels in cells than those prepared using the TFH method. Moreover, FLuc mRNA lipoplexes prepared using the MEI and TFH methods at charge ratios of 3:1 and 4:1, respectively, exhibited the highest Luc expression in cells. However, transfection with mRNA lipoplexes using the MEI and TFH methods induced moderate cytotoxicity in HeLa cells (46 and 57% cell viability, respectively). Furthermore, Cy5-labeled mRNA lipoplexes, which were prepared using the MEI method, showed higher cellular uptake of mRNA than those prepared using the TFH method. In the transfection of FLuc mRNA lipoplexes prepared using the MEI method, the storage of the lipid-ethanol solution at 37˚C for 4 months did not decrease Luc expression in HeLa cells. Additionally, FLuc mRNA lipoplexes prepared using the MEI method, induced relatively high Luc expression in human prostate carcinoma PC-3 and human liver cancer HepG2 cells with low cytotoxicity (103 and 81% cell viability, respectively). Overall, the results highlighted the potential of TC-1-12-based mRNA lipoplexes prepared using the MEI method for efficient mRNA delivery to cells.

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.

Regioselective N1-ribosylation of hydantoin: synthesis and properties of the first contracted uridine analog

Modified nucleosides are vital in mRNA vaccines. We developed a contracted uridine analog, N1-hydantoinyl-ribose, HR, using steric shields to invert the regioselectivity of the classic Vorbrüggen reaction. We report synthetic routes and explore HR features such as acidity, stability, base pairing/stacking, and crystal/solution conformation compared to uridine.

Cytoplasmic mRNA decay and quality control machineries in eukaryotes

mRNA degradation pathways have key regulatory roles in gene expression. The intrinsic stability of mRNAs in the cytoplasm of eukaryotic cells varies widely in a gene- and isoform-dependent manner and can be regulated by cellular cues, such as kinase signalling, to control mRNA levels and spatiotemporal dynamics of gene expression. Moreover, specialized quality control pathways exist to rid cells of non-functional mRNAs produced by errors in mRNA processing or mRNA damage that negatively impact translation. Recent advances in structural, single-molecule and genome-wide methods have provided new insights into the central machineries that carry out mRNA turnover, the mechanisms by which mRNAs are targeted for degradation and the general principles that govern mRNA stability at a global level. This improved understanding of mRNA degradation in the cytoplasm of eukaryotic cells is finding practical applications in the design of therapeutic mRNAs.

Optimal Chimeric Antigen Receptor (CAR)-mRNA for Transient CAR T Cell Generation

Genetically modified T lymphocytes expressing chimeric antigen receptors (CARs) are becoming increasingly important in the treatment of hematologic malignancies and are also intensively being investigated for other diseases such as autoimmune disorders and HIV. Current CAR T cell therapies predominantly use viral transduction methods which, despite their efficacy, raise safety concerns related to genomic integration and potentially associated malignancies as well as labor- and cost-intensive manufacturing. Therefore, non-viral gene transfer methods, especially mRNA-based approaches, have attracted research interest due to their transient modification and enhanced safety profile. In this study, the optimization of CAR-mRNA for T cell applications is investigated, focusing on the impact of mRNA modifications, in vitro transcription protocols, and purification techniques on the translation efficiency and immunogenicity of mRNA. Furthermore, the refined CAR-mRNA was used to generate transient CAR T cells from acute myeloid leukemia patient samples, demonstrating efficacy in vitro and proof-of-concept for clinically relevant settings. These results highlight the potential of optimized mRNA to produce transient and safe CAR T cells.

Multiarm-Assisted Design of Dendron-like Degradable Ionizable Lipids Facilitates Systemic mRNA Delivery to the Spleen

Lipid nanoparticles (LNPs) have emerged as pivotal vehicles for messenger RNA (mRNA) delivery to hepatocytes upon systemic administration and to antigen-presenting cells following intramuscular injection. However, achieving systemic mRNA delivery to non-hepatocytes remains challenging without the incorporation of targeting ligands such as antibodies, peptides, or small molecules. Inspired by comb-like polymeric architecture, here we utilized a multiarm-assisted design to construct a library of 270 dendron-like degradable ionizable lipids by altering the structures of amine heads and multiarmed tails for optimal mRNA delivery. Following in vitro high-throughput screening, a series of top-dendron-like LNPs with high transfection efficacy were identified. These dendron-like ionizable lipids facilitated greater mRNA delivery to the spleen in vivo compared to ionizable lipid analogs lacking dendron-like structure. Proteomic analysis of corona-LNP pellets showed enhancement of key protein clusters, suggesting potential endogenous targeting to the spleen. A lead dendron-like LNP formulation, 18-2-9b2, was further used to encapsulate Cre mRNA and demonstrated excellent genome modification in splenic macrophages, outperforming a spleen-tropic MC3/18PA LNP in the Ai14 mice model. Moreover, 18-2-9b2 LNP encapsulating therapeutic BTB domain and CNC homologue 1 (BACH1) mRNA exhibited proficient BACH1 expression and subsequent Spic downregulation in splenic red pulp macrophages (RPM) in a Spic-GFP transgene model upon intravenous administration. These results underscore the potential of dendron-like LNPs to facilitate mRNA delivery to splenic macrophages, potentially opening avenues for a range of mRNA-LNP therapeutic applications, including regenerative medicine, protein replacement, and gene editing therapies.

Orthogonalized human protease control of secreted signals

Synthetic circuits that regulate protein secretion in human cells could support cell-based therapies by enabling control over local environments. Although protein-level circuits enable such potential clinical applications, featuring orthogonality and compactness, their non-human origin poses a potential immunogenic risk. In this study, we developed Humanized Drug Induced Regulation of Engineered CyTokines (hDIRECT) as a platform to control cytokine activity exclusively using human-derived proteins. We sourced a specific human protease and its FDA-approved inhibitor. We engineered cytokines (IL-2, IL-6 and IL-10) whose activities can be activated and abrogated by proteolytic cleavage. We used species specificity and re-localization strategies to orthogonalize the cytokines and protease from the human context that they would be deployed in. hDIRECT should enable local cytokine activation to support a variety of cell-based therapies, such as muscle regeneration and cancer immunotherapy. Our work offers a proof of concept for the emerging appreciation of humanization in synthetic biology for human health.

Concise Affinity-Based Purification of Ligated mRNA for Structure-Activity Relationship Studies of Nucleosugar Modification Patterns

Position-specific nucleoside sugar modifications have been shown to improve the translational activity and stability of chemically synthesized mRNA. For pharmaceutical applications of chemically modified mRNAs, a rapid purification methodology is imperative to identify the optimal modification pattern. However, while the chemical synthesis of mRNAs can be accomplished by splint ligation of oligonucleotide fragments, the current purification method for ligated mRNAs based on denaturing polyacrylamide gel electrophoresis tends to be time consuming. In this study, we developed a two-step affinity purification method for rapid sample preparation. In this method, ligated mRNA is captured by oligo dT magnetic beads and streptavidin magnetic beads with 3'-biotinylated oligo DNA, which are complementary to the 3'-poly(A) and 5' terminal sequences of the target mRNA, respectively. Therefore, the target mRNA can be isolated from a complex mixture of splint ligations. Using this method, six sugar-modified mRNAs were simultaneously purified, and the translational activities of these mRNAs were evaluated immediately after purification. The results demonstrate that this methodology is suitable for the rapid preparation of various chemically synthesized mRNAs to identify their optimal modification patterns.

Development and Evaluation of the Immunogenic Potential of an Unmodified Nucleoside mRNA Vaccine for Herpes Zoster

BACKGROUND/OBJECTIVES

Approved mRNA vaccines commonly use sequences modified with pseudouridine to enhance translation efficiency and mRNA stability. However, this modification can result in ribosomal frameshifts, reduced immunogenicity, and higher production costs. This study aimed to explore the potential of unmodified mRNA sequences for varicella-zoster virus (VZV) and evaluate whether codon optimization could overcome the limitations of pseudouridine modification.

METHODS

We utilized artificial intelligence (AI) to design several unmodified gE mRNA sequences for VZV, considering factors such as codon preference and secondary structure. The optimized mRNA sequences were assessed for protein expression levels in vitro and were subsequently used to develop a vaccine, named Vac07, encapsulated in a lipid nanoparticle (LNP) delivery system. The immunogenicity of Vac07 was evaluated in mice.

RESULTS

Codon-optimized mRNA sequences showed significantly higher protein expression levels in vitro compared to wild-type (WT) sequences. Vaccination with Vac07 demonstrated immunogenicity in mice that was comparable to, or even superior to, the licensed Shingrix vaccine, characterized by a stronger Th1-biased antibody response and a slightly more robust Th1-type cellular response.

CONCLUSIONS

Codon-optimized unmodified mRNA sequences may also represent a viable approach for mRNA vaccine development. These optimized sequences have the potential to lower production costs while possibly enhancing the immunogenicity of mRNA vaccines. Vac07, developed using this method, shows promise as a potentially more efficient and cost-effective mRNA vaccine candidate for VZV.

Clinical advances of mRNA vaccines for cancer immunotherapy

The development of mRNA vaccines represents a significant advancement in cancer treatment, with more than 120 clinical trials to date demonstrating their potential across various malignancies, including lung, breast, prostate, melanoma, and more challenging cancers such as pancreatic and brain tumors. These vaccines work by encoding tumor-specific antigens and immune-stimulating molecules, effectively activating the immune system to target and eliminate cancer cells. Despite these promising advancements, significant challenges remain, particularly in achieving efficient delivery and precise regulation of the immune response. This review provides a comprehensive overview of recent clinical progress in mRNA cancer vaccines, discusses the innovative strategies being employed to overcome existing hurdles, and explores future directions, including the integration of CRISPR-Cas9 technology and advancements in mRNA design. Our aim is to provide insights into the ongoing research and clinical trials, highlighting the transformative potential of mRNA vaccines in advancing oncology and improving patient outcomes.

DARPin-induced reactivation of p53 in HPV-positive cells

Infection of cells with high-risk strains of the human papillomavirus (HPV) causes cancer in various types of epithelial tissue. HPV infections are responsible for ~4.5% of all cancers worldwide. Tumorigenesis is based on the inactivation of key cellular control mechanisms by the viral proteins E6 and E7. The HPV E6 protein interacts with the cellular E3 ligase E6AP, and this complex binds to the p53 DNA-binding domain, which results in degradation of p53. Inhibition of this interaction has the potential to reactivate p53, thus preventing oncogenic transformation. Here we describe the characterization of a designed ankyrin repeat protein that binds to the same site as the HPV E6 protein, thereby displacing the E3 ligase and stabilizing p53. Interaction with the designed ankyrin repeat protein does not affect p53 DNA binding or the crucial MDM2 negative feedback loop but reactivates a p53-dependent transcriptional program in HeLa (HPV18-positive) and SiHa (HPV16-positive) cells, suggesting a potential therapeutic use.

Selective Reduction of Esters to Access Aldehydes Using Fiddler Crab-Type Boranes

The partial reduction of esters to aldehydes is a fundamentally important transformation for the synthesis of numerous fine chemicals and consumer goods. However, despite the many efforts, limitations have persisted, such as competing overreduction, low reproducibility, use of exigent reaction conditions and hazardous chemicals. Here, we report a novel catalyst family with a unique steric design which promotes the catalytic partial reduction of esters with unprecedented, near-perfect selectivity and efficiency. This metal-free catalytic method is ready to be placed at the disposal of chemists to provide valuable aldehyde intermediates and products and shows promise for streamlining synthetic methods in academic and industrial settings.

mRNA vaccines in the context of cancer treatment: from concept to application

Immuno-oncology has witnessed remarkable advancements in the past decade, revolutionizing the landscape of cancer therapeutics in an encouraging manner. Among the diverse immunotherapy strategies, mRNA vaccines have ushered in a new era for the therapeutic management of malignant diseases, primarily due to their impressive impact on the COVID-19 pandemic. In this comprehensive review, we offer a systematic overview of mRNA vaccines, focusing on the optimization of structural design, the crucial role of delivery materials, and the administration route. Additionally, we summarize preclinical studies and clinical trials to provide valuable insights into the current status of mRNA vaccines in cancer treatment. Furthermore, we delve into a systematic discussion on the significant challenges facing the current development of mRNA tumor vaccines. These challenges encompass both intrinsic and external factors that are closely intertwined with the successful application of this innovative approach. To pave the way for a more promising future in cancer treatments, a deeper understanding of immunological mechanisms, an increasing number of high-quality clinical trials, and a well-established manufacturing platform are crucial. Collaborative efforts between scientists, clinicians, and industry engineers are essential to achieving these goals.

Effective cancer immunotherapy combining mRNA-encoded bispecific antibodies that induce polyclonal T cell engagement and PD-L1-dependent 4-1BB costimulation

Background

Immune checkpoint inhibitors have revolutionized cancer therapy, but many patients fail to respond or develop resistance, often due to reduced T cell activity. Costimulation via 4-1BB has emerged as a promising approach to enhance the effector function of antigen-primed T cells. Bispecific T cell-engaging (TCE) antibodies are an effective way to provide tumor-specific T cell receptor-mediated signaling to tumor-infiltrating lymphocytes. mRNA-based delivery of bispecific antibodies, offer a novel approach to enhance tumor-specific immune responses while minimizing adverse effects.

Methods

Two bispecific antibodies were generated: the EGFR x CD3 TCE antibody (LiTE) and the PD-L1 x 4-1BB costimulatory antibody (LiTCo), which was further fused to a high FcRn albumin variant (Albu-LiTCo). The mRNA encoding these bispecific antibodies contains an N1-methylpseudouridine modified nucleoside and regulatory sequences to ensure proper expression and stability. A series of in vitro assays and cell-based analyses were performed to characterize both antibodies. The in vivo efficacy of the mRNA-encoded bispecific antibodies was evaluated in xenograft tumor models expressing EGFR.

Results

We investigated the combined effect of two mRNA-encoded Fc-free bispecific antibodies with complementary mechanisms of action: an EGFR-targeting TCE and a half-life extended PD-L1 x 4-1BB costimulatory antibody. The mRNAs encoding both bispecific LiTERNA and Albu-LiTCoRNA, showed similar binding specificity and in vitro function to their protein analogues. Pharmacokinetic studies demonstrated sustained expression of both bispecific antibodies following intravenous administration of the mRNAs formulated using a polymer/lipid-based nanoparticle (LNP) but different pharmacokinetic profiles, shorter for the TCE and longer for the PD-L1 x 4-1BB. When administered as a mRNA-LNP combination (ComboRNA), the growth of EGFR-positive tumors in immunocompetent mice was significantly inhibited, resulting in tumor regression in 20% of cases with no associated toxicity. Histological analysis confirmed increased T cell infiltration in the tumors treated with LITERNA and ComboRNA. Repeated administration resulted in sustained production of bispecific antibodies with different exposure cycles and potent antitumor activity with a favorable safety profile.

Conclusions

These results highlight the potential of combining two mRNA-encoded bispecific antibodies with different mechanisms of action and programmable half-life for cancer immunotherapy.

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.

Affordable mRNA Novel Proteins, Recombinant Protein Conversions, and Biosimilars-Advice to Developers and Regulatory Agencies

mRNA technology can replace the expensive recombinant technology for every type of protein, making biological drugs more affordable. It can also expedite the entry of new biological drugs, and copies of approved mRNA products can be treated as generic or biosimilar products due to their chemical nature. The introduction of hundreds of new protein drugs have been blocked due to the high cost of recombinant development. The low CAPEX and OPEX associated with mRNA technology bring it within the reach of developing countries that are currently deprived of life-saving biological drugs. In this paper, we advise developers to introduce novel proteins and switch recombinant manufacturing to mRNA delivery, and we further advise regulatory authorities to allow for the approval of copies of mRNA products with less testing. We anticipate that mRNA technology will make protein drugs, such as natural and engineered proteins, monoclonal antibodies, and vaccines, accessible to billions of patients worldwide.

State of the art and perspectives of gene therapy in heart failure. A scientific statement of the Heart Failure Association of the ESC, the ESC Council on Cardiovascular Genomics and the ESC Working Group on Myocardial & Pericardial Diseases

Gene therapy has recently become a reality in the treatment of cardiovascular diseases. Strategies to modulate gene expression using antisense oligonucleotides or small interfering RNA are proving to be safe and effective in the clinic. Adeno-associated viral vector-based gene delivery and CRISPR-Cas9-based genome editing have emerged as efficient strategies for gene delivery and repair in humans. Overall, gene therapy holds the promise not only of expanding current treatment options, but also of intervening in previously untackled causal disease mechanisms with little side effects. This scientific statement provides a comprehensive overview of the various modalities of gene therapy used to treat heart failure and some of its risk factors, and their application in the clinical setting. It discusses specifically the possibilities of gene therapy for hereditary heart diseases and (non)-genetic heart failure. Furthermore, it addresses safety and clinical trial design issues and challenges for future regulatory strategies.

A Practical Guideline for MicroRNA Sequencing Data Analysis in Chronic Lymphocytic Leukemia

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. They have been associated with several diseases and cancers, including chronic lymphocytic leukemia (CLL). CLL is the most common form of adult leukemia, and its pathogenesis is driven by the deletion of miRNAs, such as the miR-15a/16-1 cluster. In addition to initiating the development of CLL, the function of miRNAs in regulating the progression of this tumor remains to be investigated. Here, we present a computational pipeline, from the processing of miRNA sequencing files to functional analysis, including differential gene expression and gene set enrichment analysis.We exemplified the utility of the pipeline by applying it to genome-wide small RNA sequencing data from a cohort of CLL patients. The analysis revealed dysregulated expression profiles of miRNAs in CLL. The target genes of these miRNAs are not only associated with the response of CLL patients to current therapies but also involved in several cancer hallmarks, including the avoidance of cell death, the deregulation of cellular energetics, the activation of invasion and metastasis, and genome instability. The identified miRNA-gene interactions offer valuable insights for developing targeted therapies for CLL. In addition, we underscored the importance of a practical and robust computational pipeline to ensure the reliability and reproducibility of miRNA sequencing data analysis.

Newly developed mRNA vaccines induce immune responses in Litopenaeus vannamei shrimps during primary vaccination

White spot syndrome virus (WSSV) causes highly destructive infection in crustacean aquaculture, often resulting in 100% mortality within a week. However, there is lack of studies addressing the safety issues of WSSV vaccines in shrimps. In this study, WSSV VP28 mRNA vaccines were developed using codon deoptimization approach. These vaccines were administered to Litopenaeus vannamei shrimps at various dosages to access their safety and the shrimps' immune responses using quantification PCR (qPCR). The findings of this study indicate that the expression level of codon deoptimized VP28 mRNA vaccines are lower compared to the wild type VP28 vaccines, as observed through a comparison of bioinformatic predictions and experimental results. Additionally, the total haemocyte count (THC) in shrimps injected with codon deoptimized VP28 vaccine was higher than those injected with wild type VP28 vaccines. Furthermore, the expression of immune-related genes differed between codon deoptimized and wild type VP28 vaccines. In summary, the results suggest that 0.01 μg codon deoptimized VP28-D1 mRNA vaccine is the most promising WSSV mRNA vaccine, displaying low pathogenicity and expression in shrimps. To the best of our knowledge, this research represents the first attempt to attenuate WSSV using codon deoptimization method and development of a potential mRNA vaccine for shrimp purpose. The study addresses an important gap in shrimp vaccine research, offering potential solutions for WSSV control in shrimps.

Human adipose-derived multipotent stromal cells enriched with IL-10 modRNA improve diabetic wound healing: Trigger the macrophage phenotype shift

Diabetic wounds present a significant challenge in regenerative medicine due to impaired healing, characterized by prolonged inflammation and deficient tissue repair, primarily caused by a skewed pro-inflammatory macrophage phenotype. This study investigates the therapeutic potential of interleukin-10 (IL-10) chemically modified mRNA (modRNA)-enriched human adipose-derived multipotent stromal cells (hADSCs) in a well-established murine model of diabetic wounds. The modRNAs used in this study were chemically modified using N1-methylpseudouridine-5'-triphosphate (m1Ψ) by substituting uridine-5-triphosphate. In vitro experiments demonstrated that IL-10 modRNA-transfected hADSCs effectively modulated macrophage polarization towards an anti-inflammatory phenotype. In vivo experiments with a well-established murine model demonstrated that transplantation of hADSCsmodIL-10 on postoperative day 5 (POD5) significantly improved wound healing outcomes, including accelerated wound closure, enhanced re-epithelialization, promoted M2 polarization, improved collagen deposition, and increased neovascularization. This study concludes that IL-10 modRNA-enriched hADSCs offer a promising therapeutic approach for diabetic wound healing, with the timing of IL-10 administration playing a crucial role in its effectiveness. These cells modulate macrophage polarization and promote tissue repair, demonstrating their potential for improving the management of diabetic wounds.

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.

Combinatorial design of siloxane-incorporated lipid nanoparticles augments intracellular processing for tissue-specific mRNA therapeutic delivery

Systemic delivery of messenger RNA (mRNA) for tissue-specific targeting using lipid nanoparticles (LNPs) holds great therapeutic potential. Nevertheless, how the structural characteristics of ionizable lipids (lipidoids) impact their capability to target cells and organs remains unclear. Here we engineered a class of siloxane-based ionizable lipids with varying structures and formulated siloxane-incorporated LNPs (SiLNPs) to control in vivo mRNA delivery to the liver, lung and spleen in mice. The siloxane moieties enhance cellular internalization of mRNA-LNPs and improve their endosomal escape capacity, augmenting their mRNA delivery efficacy. Using organ-specific SiLNPs to deliver gene editing machinery, we achieve robust gene knockout in the liver of wild-type mice and in the lungs of both transgenic GFP and Lewis lung carcinoma (LLC) tumour-bearing mice. Moreover, we showed effective recovery from viral infection-induced lung damage by delivering angiogenic factors with lung-targeted Si5-N14 LNPs. We envision that our SiLNPs will aid in the clinical translation of mRNA therapeutics for next-generation tissue-specific protein replacement therapies, regenerative medicine and gene editing.

Investigational gene expression inhibitors for the treatment of idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial lung disease of unknown cause that occurs primarily in older adults and is associated with poor quality of life and substantial healthcare utilization. IPF has a dismal prognosis. Indeed, first-line therapy, which includes nintedanib and pirfenidone, does not stop disease progression and is often associated with tolerability issues. Therefore, there remains a high medical need for more efficacious and better tolerated treatments.

AREAS COVERED

Gene therapy is a relatively unexplored field of research in IPF that has the potential to mitigate a range of profibrotic pathways by introducing genetic material into cells. Here, we summarize and critically discuss publications that have explored the safety and efficacy of gene therapy in experimentally-induced pulmonary fibrosis in animals, as clinical studies in humans have not been published yet.

EXPERT OPINION

The application of gene therapy in pulmonary fibrosis requires further investigation to address several technical and biological hurdles, improve vectors' design, drug delivery, and target selection, mitigate off-target effects and develop markers of gene penetration into target cells. Long-term clinical data are needed to bring gene therapy in IPF one step closer to practice.

Tumor Microenvironment-Responsive Polymer-Based RNA Delivery Systems for Cancer Treatment

Ribonucleic acid (RNA) therapeutics offer a broad prospect in cancer treatment. However, their successful application requires overcoming various physiological barriers to effectively deliver RNAs to the target sites. Currently, a number of RNA delivery systems based on polymeric nanoparticles are developed to overcome these barriers in RNA delivery. This work provides an overview of the existing RNA therapeutics for cancer gene therapy, and particularly summarizes those that are entering the clinical phase. This work then discusses the core features and latest research developments of tumor microenvironment-responsive polymer-based RNA delivery carriers which are designed based on the pathological characteristics of the tumor microenvironment. Finally, this work also proposes opportunities for the transformation of RNA therapies into cancer immunotherapy methods in clinical applications.

Revolutionizing Heart Failure Therapy: Harnessing IVT mRNA and Fusion Protein Technology to Prolong rhBNP Half-Life

PURPOSE

Recombinant human B-type natriuretic peptide (rhBNP) has been extensively proven to be an effective mean of heart failure (HF) therapy, but its clinical application is limited by its very short half-life. This study aims to combine in vitro transcribed mRNA (IVT mRNA) and fusion protein technology to develop a rhBNP-Fc mRNA drug with long half-life, high efficiency and few side effects to treat HF.

METHODS

The rhBNP-Fc fusion mRNA with IgG4-Fc sequence was produced by IVT technology. rhBNP-Fc mRNA was transfected into HEK293T cells to examine the expression in vitro. rhBNP-Fc mRNA encapsulated in LNP was injected into normal mice to detect the translation efficiency, half-life and negative effects in vivo. Finally, it was injected into doxorubicin-induced HF mice to screen the cardiac protective effect.

RESULTS

The rhBNP-Fc fusion mRNA extended the half-life of rhBNP, showing sustained expression in cell line for at least one day. rhBNP-Fc mRNA translation showed dose-dependent levels, and was still detectable 5 d after injection in vivo. In the HF mouse model, a single administration of rhBNP-Fc mRNA-LNP improved cardiac function, including improving heart ejection and reducing HF biomarkers expression. Additionally, rhBNP-Fc mRNA-LNP treatment mitigated myocardial damage, normalized cardiomyocyte structure, and reduced the levels of pro-inflammatory cytokines.

CONCLUSION

The rhBNP-Fc mRNA has the potential to serve as an alternative to traditional protein therapies, thereby reducing clinical dosages, injection frequencies, and treatment costs. Our findings offer new insights into the development and application of mRNA drugs, emphasizing their therapeutic potential in long-acting drugs.

Enhancing Cytoplasmic Expression of Exogenous mRNA Through Dynamic Mechanical Stimulation

Ionizable lipid nanoparticles (LNPs) are pivotal in combating COVID-19, and numerous preclinical and clinical studies have highlighted their potential in nucleic acid-based therapies and vaccines. However, the effectiveness of endosomal escape for the nucleic acid cargos encapsulated in LNPs is still low, leading to suboptimal treatment outcomes and side effects. Hence, improving endosomal escape is crucial for enhancing the efficacy of nucleic acid delivery using LNPs. Here, a mechanical oscillation (frequency: 65 Hz) is utilized to prompt the LNP-mediated endosomal escape. The results reveal this mechanical oscillation can induce the combination and fusion between LNPs with opposite surface charges, enhance endosomal escape of mRNA, and increase the transfection efficiency of mRNA. Additionally, cell viability remains high at 99.3% after treatment with oscillation, which is comparable to that of untreated cells. Furthermore, there is no obvious damage to mitochondrial membrane potential and Golgi apparatus integrity. Thus, this work presents a user-friendly and safe approach to enhancing endosomal escape of mRNA and boosting gene expression. As a result, this work can be potentially utilized in both research and clinical fields to facilitate LNP-based delivery by enabling more effective release of LNP-encapsulated cargos from endosomes.

Polymers for mRNA Delivery

mRNA delivery has emerged as a transformative approach in biotechnology and medicine, offering a versatile platform for the development of novel therapeutics. Unlike traditional small molecule drugs or protein-based biologics, mRNA therapeutics have the unique ability to direct cells to generate therapeutic proteins, allowing for precise modulation of biological processes. The delivery of mRNA into target cells is a critical step in realizing the therapeutic potential of this technology. In this review, our focus is on the latest advancements in designing functional polymers to achieve efficient mRNA delivery. Biodegradable polymers and low molecular weight polymers in addressing the balance in mRNA binding and release are summarized. Benefiting from the excellent performance of lipid nanoparticles in mRNA delivery, polymer/lipid hybrid nanostructures are also included. Finally, the challenges and future prospects in the development of polymer-based mRNA delivery systems are discussed.

Seasonal influenza vaccine performance and the potential benefits of mRNA vaccines

Influenza remains a public health threat, partly due to suboptimal effectiveness of vaccines. One factor impacting vaccine effectiveness is strain mismatch, occurring when vaccines no longer match circulating strains due to antigenic drift or the incorporation of inadvertent (eg, egg-adaptive) mutations during vaccine manufacturing. In this review, we summarize the evidence for antigenic drift of circulating viruses and/or egg-adaptive mutations occurring in vaccine strains during the 2011-2020 influenza seasons. Evidence suggests that antigenic drift led to vaccine mismatch during four seasons and that egg-adaptive mutations caused vaccine mismatch during six seasons. These findings highlight the need for alternative vaccine development platforms. Recently, vaccines based on mRNA technology have demonstrated efficacy against SARS-CoV-2 and respiratory syncytial virus and are under clinical evaluation for seasonal influenza. We discuss the potential for mRNA vaccines to address strain mismatch, as well as new multi-component strategies using the mRNA platform to improve vaccine effectiveness.

Recent progress in mRNA cancer vaccines

The research and development of messenger RNA (mRNA) cancer vaccines have gradually overcome numerous challenges through the application of personalized cancer antigens, structural optimization of mRNA, and the development of alternative RNA-based vectors and efficient targeted delivery vectors. Clinical trials are currently underway for various cancer vaccines that encode tumor-associated antigens (TAAs), tumor-specific antigens (TSAs), or immunomodulators. In this paper, we summarize the optimization of mRNA and the emergence of RNA-based expression vectors in cancer vaccines. We begin by reviewing the advancement and utilization of state-of-the-art targeted lipid nanoparticles (LNPs), followed by presenting the primary classifications and clinical applications of mRNA cancer vaccines. Collectively, mRNA vaccines are emerging as a central focus in cancer immunotherapy, offering the potential to address multiple challenges in cancer treatment, either as standalone therapies or in combination with current cancer treatments.

Antigen Delivery Platforms for Next-Generation Coronavirus Vaccines

The COVID-19 pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is in its sixth year and is being maintained by the inability of current spike-alone-based COVID-19 vaccines to prevent transmission leading to the continuous emergence of variants and sub-variants of concern (VOCs). This underscores the critical need for next-generation broad-spectrum pan-Coronavirus vaccines (pan-CoV vaccine) to break this cycle and end the pandemic. The development of a pan-CoV vaccine offering protection against a wide array of VOCs requires two key elements: (1) identifying protective antigens that are highly conserved between passed, current, and future VOCs; and (2) developing a safe and efficient antigen delivery system for induction of broad-based and long-lasting B- and T-cell immunity. This review will (1) present the current state of antigen delivery platforms involving a multifaceted approach, including bioinformatics, molecular and structural biology, immunology, and advanced computational methods; (2) discuss the challenges facing the development of safe and effective antigen delivery platforms; and (3) highlight the potential of nucleoside-modified mRNA encapsulated in lipid nanoparticles (LNP) as the platform that is well suited to the needs of a next-generation pan-CoV vaccine, such as the ability to induce broad-based immunity and amenable to large-scale manufacturing to safely provide durable protective immunity against current and future Coronavirus threats.

Artificial intelligence-driven rational design of ionizable lipids for mRNA delivery

Lipid nanoparticles (LNPs) have proven effective in mRNA delivery, as evidenced by COVID-19 vaccines. Its key ingredient, ionizable lipids, is traditionally optimized by inefficient and costly experimental screening. This study leverages artificial intelligence (AI) and virtual screening to facilitate the rational design of ionizable lipids by predicting two key properties of LNPs, apparent pKa and mRNA delivery efficiency. Nearly 20 million ionizable lipids were evaluated through two iterations of AI-driven generation and screening, yielding three and six new molecules, respectively. In mouse test validation, one lipid from the initial iteration, featuring a benzene ring, demonstrated performance comparable to the control DLin-MC3-DMA (MC3). Notably, all six lipids from the second iteration equaled or outperformed MC3, with one exhibiting efficacy akin to a superior control lipid SM-102. Furthermore, the AI model is interpretable in structure-activity relationships.

RNA Structure: Past, Future, and Gene Therapy Applications

First believed to be a simple intermediary between the information encoded in deoxyribonucleic acid and that functionally displayed in proteins, ribonucleic acid (RNA) is now known to have many functions through its abundance and intricate, ubiquitous, diverse, and dynamic structure. About 70-90% of the human genome is transcribed into protein-coding and noncoding RNAs as main determinants along with regulatory sequences of cellular to populational biological diversity. From the nucleotide sequence or primary structure, through Watson-Crick pairing self-folding or secondary structure, to compaction via longer distance Watson-Crick and non-Watson-Crick interactions or tertiary structure, and interactions with RNA or other biopolymers or quaternary structure, or with metabolites and biomolecules or quinary structure, RNA structure plays a critical role in RNA's lifecycle from transcription to decay and many cellular processes. In contrast to the success of 3-dimensional protein structure prediction using AlphaFold, RNA tertiary and beyond structures prediction remains challenging. However, approaches involving machine learning and artificial intelligence, sequencing of RNA and its modifications, and structural analyses at the single-cell and intact tissue levels, among others, provide an optimistic outlook for the continued development and refinement of RNA-based applications. Here, we highlight those in gene therapy.

Modified mRNA-based gene editing reveals sarcomere-based regulation of gene expression in human induced-pluripotent stem cell-derived cardiomyocytes

Mutations in genes coding sarcomere components are the major causes of human inherited cardiomyopathy. Genome editing is widely applied to genetic modification of human pluripotent stem cells (hPSCs) before hPSCs were differentiated into cardiomyocytes to model cardiomyopathy. Whether genetic mutations influence the early hPSC differentiation process or solely the terminally differentiated cardiomyocytes during cardiac pathogenesis remains challenging to distinguish. To solve this problem, here we harnessed chemically modified mRNA (modRNA) and synthetic single-guide RNA to develop an efficient genome editing approach in hPSC-derived cardiomyocytes (hPSC-CMs). We showed that modRNA-based CRISPR/Cas9 mutagenesis of TNNT2, the coding gene for cardiac troponin T, results in sarcomere disassembly and contractile dysfunction in hPSC-CMs. These structural and functional phenotypes were associated with profound downregulation of oxidative phosphorylation genes and upregulation of cardiac stress markers NPPA and NPPB. These data confirmed that sarcomeres regulate gene expression in hPSC-CMs and highlighted the RNA technology as a powerful tool to achieve stage-specific genome editing during hPSC differentiation.

Ex Vivo Delivery of mRNA to Immune Cells via a Nonendosomal Route Obviates the Need for Nucleoside Modification

Base modification and the use of lipid nanoparticles are thought to be essential for efficient in vivo delivery and expression of mRNA. However, for ex vivo immune cell engineering, the need for either of the two is unclear. Previous reports have suggested that nucleic acids may be efficiently delivered to immune cells ex vivo, through a nonendosomal delivery route, but the need for base modification has not been determined. Herein, we demonstrate that when a nonendosomal delivery method is used, unmodified mRNA performs equally well to the commonly used base-modified mRNA, including the N 1 methyl pseudouridine modification, in terms of protein expression and inflammatory response in cells. However, if an endosomal delivery route is used, then N 1 methyl pseudouridine modification is necessary for high expression and low inflammatory response, as demonstrated by others as well. Overall, we show that nonendosomal mRNA delivery renders nucleoside modifications nonessential and that unmodified mRNA combined with nonendosomal delivery route may be used for efficient ex vivo mRNA-based engineering of immune cells.

Isosteric 3D Bicyclo[1.1.1]Pentane (BCP) Core-Based Lipids for mRNA Delivery and CRISPR/Cas Gene Editing

Lipid nanoparticles (LNPs) are an essential component of messenger RNA (mRNA) vaccines and genome editing therapeutics. Ionizable amino lipids, which play the most crucial role in enabling mRNA to overcome delivery barriers, have, to date, been restricted to two-dimensional (2D) architectures. Inspired by improved physicochemical properties resulting from the incorporation of three-dimensionality (3D) into small-molecule drugs, we report the creation of 3D ionizable lipid designs through the introduction of bicyclo[1.1.1]pentane (BCP) core motifs. BCP-based lipids enabled efficient in vivo mRNA delivery to the liver and spleen with significantly greater performance over 2D benzene- and cyclohexane-based analogues. Notably, lead BCP-NC2-C12 LNPs mediated ∼90% reduction in the PCSK9 serum protein level via CRISPR/Cas9 gene knockout, outperforming 2D controls and clinically used DLin-MC3-DMA LNPs at the same dose. Here, we introduce BCP-based designs with superior in vivo activity, thereby expanding the chemical scope of ionizable amino lipids from 2D to 3D and offering a promising avenue to improve mRNA and gene editing efficiency for the continued development of genetic medicines.

In Vivo Delivery Processes and Development Strategies of Lipid Nanoparticles

Lipid nanoparticles (LNPs) represent an advanced and highly efficient delivery system for RNA molecules, demonstrating exceptional biocompatibility and remarkable delivery efficiency. This is evidenced by the clinical authorization of three LNP formulations: Patisiran, BNT162b2, and mRNA-1273. To further maximize the efficacy of RNA-based therapy, it is imperative to develop more potent LNP delivery systems that can effectively protect inherently unstable and negatively charged RNA molecules from degradation by nucleases, while facilitating their cellular uptake into target cells. Therefore, this review presents feasible strategies commonly employed for the development of efficient LNP delivery systems. The strategies encompass combinatorial chemistry for large-scale synthesis of ionizable lipids, rational design strategy of ionizable lipids, functional molecules-derived lipid molecules, the optimization of LNP formulations, and the adjustment of particle size and charge property of LNPs. Prior to introducing these developing strategies, in vivo delivery processes of LNPs, a crucial determinant influencing the clinical translation of LNP formulations, is described to better understand how to develop LNP delivery systems.

Efficient circular RNA synthesis for potent rolling circle translation

Circular RNA (circRNA) is a candidate for next-generation messenger RNA therapeutics owing to its remarkable stability. Here we describe trans-splicing-based methods for the synthesis of circRNAs over 8,000 nucleotides. The methods are independent of bacterial sequences, outperform the permuted intron-exon method and allow for the incorporation of RNA modifications. The resulting unmodified circRNAs, which incorporate sequences from human 28S ribosomal RNA, display low immunogenicity and are translated more efficiently than permuted intron-exon-derived circRNAs. Additionally, by using viral internal ribosomal entry sites for rolling circle translation, we show that ribosomes can efficiently read through highly structured internal ribosomal entry sites, enhancing the efficiency of rolling circle translation by over 7,000-fold with respect to previous constructs. The efficient and reliable production of circRNA may facilitate its therapeutic use.

Crown-like Biodegradable Lipids Enable Lung-Selective mRNA Delivery and Dual-Modal Tumor Imaging In Vivo

Systemic mRNA delivery to specific cell types remains a great challenge. We herein report a new class of crown-like biodegradable ionizable lipids (CBILs) for predictable lung-selective mRNA delivery by leveraging the metal coordination chemistry. Each CBIL contains an impressive crown-like amino core that coordinates with various metal ions such as Zn2+ and further regulates the in vivo organ-targeting behavior of lipid nanoparticles (LNPs). The representative CBIL (Zn-9C-SCC-10)-formulated LNPs could exclusively deliver mRNA to the lung after systemic administration. Notably, following intravenous administration of 0.2 mg kg-1 Cre mRNA, Zn-9C-SCC-10 LNPs enabled the highly efficient gene editing of all lung epithelial and endothelial cells up to 43 and 61%, respectively, outperforming the current state-of-the-art LNPs in lung epithelial cell delivery. Moreover, compared to DLin-MC3-DMA LNPs with the addition of cationic lipid (DOTAP), our approach yielded a 44.6-fold enhancement in pulmonary mRNA expression and significantly improved biosafety in vivo. Taking advantage of paramagnetic gadolinium ion, Gd-12C-SCC-10 LNPs allowed the potent mRNA delivery to cancer cells and successfully illuminated lung tumors by magnetic and bioluminescent dual-mode imaging, facilitating the early discovery and diagnosis of lung cancer. This work will open a new avenue to rationally design predictable LNPs, as well as address the major challenges of mRNA delivery to specific cells in the lung tissues for treating a wide variety of diseases.

Quality by design for mRNA platform purification based on continuous oligo-dT chromatography

Oligo-deoxythymidine (oligo-dT) ligand-based affinity chromatography is a robust method for purifying mRNA drug substances within the manufacturing process of mRNA-based products, including vaccines and therapeutics. However, the conventional batch mode of operation for oligo-dT chromatography has certain drawbacks that reduce the productivity of this process. Here, we report a new continuous oligo-dT chromatography process for the purification of in vitro transcribed mRNA, which reduces losses, improves the efficiency of oligo-dT resin use, and intensifies the chromatography process. Furthermore, the quality by design (QbD) framework was used to establish a design space for the newly developed method. The optimization of process parameters (PPs), including salt type, salt concentration, load flow rate and mRNA load concentration both in batch and the continuous mode, achieved a greater than 90% yield (mRNA recovery) along with greater than 95% mRNA integrity and greater than 99% purity. The productivity of continuous chromatography was estimated to be 5.75-fold higher, and the operating cost was estimated 15% lower, when compared with batch chromatography. Moreover, the QbD framework was further used to map the relationship between critical quality attributes and key performance indicators as a function of critical process parameters and critical material attributes.

Current status of nucleic acid therapy and its new progress in cancer treatment

Nucleic acid is an essential biopolymer in all living cells, performing the functions of storing and transmitting genetic information and synthesizing protein. In recent decades, with the progress of science and biotechnology and the continuous exploration of the functions performed by nucleic acid, more and more studies have confirmed that nucleic acid therapy for living organisms has great medical therapeutic potential. Nucleic acid drugs began to become independent therapeutic agents. As a new therapeutic method, nucleic acid therapy plays an important role in the treatment of genetic diseases, viral infections and cancers. There are currently 19 nucleic acid drugs approved by the Food and Drug Administration (FDA). In the following review, we start from principles and advantages of nucleic acid therapy, and briefly describe development history of nucleic acid drugs. And then we give examples of various RNA therapeutic drugs, including antisense oligonucleotides (ASO), mRNA vaccines, small interfering RNA (siRNA) and microRNA (miRNA), aptamers, and small activating RNA (saRNA). In addition, we also focused on the current status of nucleic acid drugs used in cancer therapy and the breakthrough in recent years. Clinical trials of nucleic acid drugs for cancer treatment are under way, conventional radiotherapy and chemotherapy combined with the immunotherapies such as checkpoint inhibitors and nucleic acid drugs may be the main prospects for successful cancer treatment.