DLin-MC3-Containing mRNA Lipid Nanoparticles Induce an Antibody Th2-Biased Immune Response Polarization in a Delivery Route-Dependent Manner in Mice

Machine learning-assisted design of immunomodulatory lipid nanoparticles for delivery of mRNA to repolarize hyperactivated microglia

Regulating inflammatory microglia presents a promising strategy for treating neurodegenerative and autoimmune disorders, yet effective therapeutic agents delivery to these cells remains a challenge. This study investigates modified lipid nanoparticles (LNP) for mRNA delivery to hyperactivated microglia, particularly those with pro-inflammatory characteristics, utilizing supervised machine learning (ML) classifiers. We developed and screened a library of 216 LNP formulations with varying lipid compositions, N/P ratios, and hyaluronic acid (HA) modifications. The transfection efficiency of eGFP mRNA was assessed in the BV-2 murine microglia cell line under different immunological states, including resting and activated conditions (LPS-activated and IL4/IL13-activated). ML-guided morphometric analysis tracked the phenotypes of various microglia subtypes before and after transfection. Four supervised ML classifiers were investigated to predict transfection efficiency and phenotypic changes based on LNP design parameters. The Multi-Layer Perceptron (MLP) neural network emerged as the best-performing model, achieving weighted F1-scores ≥0.8. While it accurately predicted responses from LPS-activated and resting cells, it struggled with IL4/IL13-activated cells. The MLP model was validated by predicting the performance of four unseen LNP formulations delivering eGFP mRNA to LPS-activated BV2 cells. HA-LNP2 emerged as optimal formulation for delivering target IL10 mRNA, effectively suppressing inflammatory phenotypes, evidenced by shifts in cell morphology, increased IL10 expression, and reduced TNF-α levels. We also evaluated HA-LNP2 on LPS-activated human iPSC-derived microglia, confirming its efficacy in modulating inflammatory responses. This study highlights the potential of tailored LNP design and ML techniques to enhance mRNA therapy for neuroinflammatory disorders by leveraging carrier's immunogenic properties to modulate microglial responses.

An LNP-mRNA vaccine protects fish against rhabdovirus infection

mRNA vaccines are poised to revolutionize disease prevention, following the approval of their administration to humans against SARS-CoV-2. Although they have been extensively studied for human applications, their potential in the veterinary field has not been explored yet. No mRNA vaccines have yet been reported for fish, despite the urgent need for new vaccines against emerging pathogens in aquaculture. As fish are ectotherms, temperature has an impact on their immune response and on many other biological parameters, including the composition of membrane lipids. It is therefore crucial to identify whether mRNA delivery systems are suitable for in vivo expression in fish for vaccine purposes. In the present study, we developed a proof of concept for mRNA vaccination in rainbow trout, a salmonid, demonstrating the efficacy of current vaccine delivery systems in fish. We used lipid nanoparticles (LNPs), which represent the most advanced delivery technology for mRNA. LNPs use a combination of lipid components that form an encapsulating structure offering protection and promote endosome escape of the mRNA to allow its expression. In vitro assays showed that LNPs are a powerful vehicle for mRNA delivery in fish cells without substantial toxicity. In vivo imaging in adult zebrafish (Danio rerio) demonstrated that intramuscular injection of LNP-formulated egfp mRNA resulted in local expression of eGFP for up to 7 days. An LNP-based mRNA vaccine candidate encoding the viral haemorrhagic septicaemia virus (VHSV) glycoprotein induced neutralizing antibodies in rainbow trout (Oncorhynchus mykiss) and offers almost complete protection against a lethal viral challenge. Our data constitute a first proof of concept of mRNA vaccination in fish, paving the way for new developments in veterinary vaccines for aquaculture.

mRNA-based vaccines and therapies - a revolutionary approach for conquering fast-spreading infections and other clinical applications: a review

Since the beginning of the COVID-19 pandemic, the development of messenger RNA (mRNA) vaccines has made significant progress in the pharmaceutical industry. The two COVID-19 mRNA vaccines from Moderna and Pfizer/BioNTech have been approved for marketing and have made significant contributions to preventing the spread of SARS-CoV-2. In addition, mRNA therapy has brought hope to some diseases that do not have specific treatment methods or are difficult to treat, such as the Zika virus and influenza virus infections, as well as the prevention and treatment of tumors. With the rapid development of in vitro transcription (IVT) technology, delivery systems, and adjuvants, mRNA therapy has also been applied to hereditary diseases such as Fabry's disease. This article reviews the recent development of mRNA vaccines for structural modification, treatment and prevention of different diseases; delivery carriers and adjuvants; and routes of administration to promote the clinical application of mRNA therapies.

Leveraging mRNA technology for antigen based immuno-oncology therapies

The application of messenger RNA (mRNA) technology in antigen-based immuno-oncology therapies represents a significant advancement in cancer treatment. Cancer vaccines are an effective combinatorial partner to sensitize the host immune system to the tumor and boost the efficacy of immune therapies. Selecting suitable tumor antigens is the key step to devising effective vaccinations and amplifying the immune response. Tumor neoantigens are de novo epitopes derived from somatic mutations, avoiding T-cell central tolerance of self-epitopes and inducing immune responses to tumors. The identification and prioritization of patient-specific tumor neoantigens are based on advanced computational algorithms taking advantage of the profiling with next-generation sequencing considering factors involved in human leukocyte antigen (HLA)-peptide-T-cell receptor (TCR) complex formation, including peptide presentation, HLA-peptide affinity, and TCR recognition. This review discusses the development and clinical application of mRNA vaccines in oncology, with a particular focus on recent clinical trials and the computational workflows and methodologies for identifying both shared and individual antigens. While this review centers on therapeutic mRNA vaccines targeting existing tumors, it does not cover preventative vaccines. Preclinical experimental validations are crucial in cancer vaccine development, but we emphasize the computational approaches that facilitate neoantigen selection and design, highlighting their role in advancing mRNA vaccine development. The versatility and rapid development potential of mRNA make it an ideal platform for personalized neoantigen immunotherapy. We explore various strategies for antigen target identification, including tumor-associated and tumor-specific antigens and the computational tools used to predict epitopes capable of eliciting strong immune responses. We address key design considerations for enhancing the immunogenicity and stability of mRNA vaccines, as well as emerging trends and challenges in the field. This comprehensive overview highlights the therapeutic potential of mRNA-based cancer vaccines and underscores ongoing research efforts aimed at optimizing these therapies for improved clinical outcomes.

Editorial on Special Issue "State-of-Art in mRNA Therapeutics and Gene Delivery"

RNA therapeutics are a class of medicines based on the insertion of a specific genetic message (mRNA) into the cells and the silencing or gene editing of a specific mRNA [...].

COVID-19 vaccine adverse events: Evaluating the pathophysiology with an emphasis on sulfur metabolism and endotheliopathy

In this narrative review, we assess the pathophysiology of severe adverse events that presented after vaccination with DNA and mRNA vaccines against COVID-19. The focus is on the perspective of an undersulfated and degraded glycocalyx, considering its impact on immunomodulation, inflammatory responses, coagulation and oxidative stress. The paper explores various factors that lead to glutathione and inorganic sulfate depletion and their subsequent effect on glycocalyx sulfation and other metabolites, including hormones. Components of COVID-19 vaccines, such as DNA and mRNA material, spike protein antigen and lipid nanoparticles, are involved in possible cytotoxic effects. The common thread connecting these adverse events is endotheliopathy or glycocalyx degradation, caused by depleted glutathione and inorganic sulfate levels, shear stress from circulating nanoparticles, aggregation and formation of protein coronas; leading to imbalanced immune responses and chronic release of pro-inflammatory cytokines, ultimately resulting in oxidative stress and systemic inflammatory response syndrome. By understanding the underlying pathophysiology of severe adverse events, better treatment options can be explored.

mRNA-based HIV-1 vaccines

SUMMARYThe success of the Severe Acute Respiratory Syndrome Coronavirus 2 mRNA vaccines to lessen/prevent severe COVID-19 opened new opportunities to develop RNA vaccines to fight other infectious agents. HIV-1 is a lentivirus that integrates into the host cell genome and persists for the lifetime of infected cells. Multiple mechanisms of immune evasion have posed significant obstacles to the development of an effective HIV-1 vaccine over the last four decades since the identification of HIV-1. Recently, attempts to address some of these challenges have led to multiple studies that manufactured, optimized, and tested, in different animal models, mRNA-based HIV-1 vaccines. Several clinical trials have also been initiated or are planned to start soon. Here, we review the current strategies applied to HIV-1 mRNA vaccines, discuss different targeting approaches, summarize the latest findings, and offer insights into the challenges and future of HIV-1 mRNA vaccines.

Optimizing mRNA-Loaded Lipid Nanoparticles as a Potential Tool for Protein-Replacement Therapy

Lipid nanoparticles (LNPs) tailored for mRNA delivery were optimized to serve as a platform for treating metabolic diseases. Four distinct lipid mixes (LMs) were formulated by modifying various components: LM1 (ALC-0315/DSPC/Cholesterol/ALC-0159), LM2 (ALC-0315/DOPE/Cholesterol/ALC-0159), LM3 (ALC-0315/DSPC/Cholesterol/DMG-PEG2k), and LM4 (DLin-MC3-DMA/DSPC/Cholesterol/ALC-0159). LNPs exhibited stability and homogeneity with a mean size of 75 to 90 nm, confirmed by cryo-TEM and SAXS studies. High mRNA encapsulation (95-100%) was achieved. LNPs effectively delivered EGFP-encoding mRNA to HepG2 and DC2.4 cell lines. LNPs induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs), revealing that LM1, LM2, and LM4 induced 1.5- to 4-fold increases in IL-8, TNF-α, and MCP-1 levels, while LM3 showed minimal changes. Reporter mRNA expression was observed in LNP-treated PBMCs. Hemotoxicity studies confirmed formulation biocompatibility with values below 2%. In vivo biodistribution in mice post intramuscular injection showed significant mRNA expression, mainly in the liver. The modification of LNP components influenced reactogenicity, inflammatory response, and mRNA expression, offering a promising platform for selecting less reactogenic carriers suitable for repetitive dosing in metabolic disease treatment.

Lipopolymer mediated siRNA delivery targeting aberrant oncogenes for effective therapy of myeloid leukemia in preclinical animal models

The clinical development of tyrosine kinase inhibitors (TKI) has led to great strides in improving the survival of chronic myeloid leukemia (CML) and acute myeloid leukemia (AML) patients. But even the new generation TKIs are rendered futile in the face of evolving landscape of acquired mutations leading to drug resistance, necessitating the pursuit of alternative therapeutic approaches. In contrast to exploiting proteins as targets like most conventional drugs and TKIs, RNA Interference (RNAi) exerts its therapeutic action towards disease-driving aberrant genes. To realize the potential of RNAi, the major challenge is to efficiently deliver the therapeutic mediator of RNAi, small interfering RNA (siRNA) molecules. In this study, we explored the feasibility of using aliphatic lipid (linoleic acid and lauric acid)-grafted polymers (lipopolymers) for the delivery of siRNAs against the FLT3 oncogene in AML and BCR-ABL oncogene in CML. The lipopolymer delivered siRNA potently suppressed the proliferation AML and CML cells via silencing of the targeted oncogenes. In both AML and CML subcutaneous xenografts generated in NCG mice, intravenously administered lipopolymer/siRNA complexes displayed significant inhibitory effect on tumor growth. Combining siFLT3 complexes with gilteritinib allowed for reduction of effective drug dosage, longer duration of remission, and enhanced survival after relapse, compared to gilteritinib monotherapy. Anti-leukemic activity of siBCR-ABL complexes was similar in wild-type and TKI-resistant cells, and therapeutic efficacy was confirmed in vivo through prolonged survival of the NCG hosts systemically implanted with TKI-resistant cells. These results demonstrate the preclinical efficacy of lipopolymer facilitated siRNA delivery, providing a novel therapeutic platform for myeloid leukemias.

Considerations on the Design of Lipid-based mRNA Vaccines Against Cancer

Throughout the last decades, mRNA vaccines have been developed as a cancer immunotherapeutic and the technology recently gained momentum during the COVID-19 pandemic. Recent promising results obtained from clinical trials investigating lipid-based mRNA vaccines in cancer therapy further highlighted the potential of this therapy. Interestingly, while the technologies being used in authorized mRNA vaccines for the prevention of COVID-19 are relatively similar, mRNA vaccines in clinical development for cancer vaccination show marked differences in mRNA modification, lipid carrier, and administration route. In this review, we describe findings on how these factors can impact the potency of mRNA vaccines in cancer therapy and provide insights into the complex interplay between them. We discuss how lipid carrier composition can affect passive targeting to immune cells to improve the efficacy and safety of mRNA vaccines. Finally, we summarize strategies that are established or still being explored to improve the efficacy of mRNA cancer vaccines and include next-generation vaccines that are on the horizon in clinical development.

RNA-Based Vaccines and Therapeutics Against Intracellular Pathogens

RNA-based vaccines have sparked a paradigm shift in the treatment and prevention of diseases by nucleic acid medicines. There has been a notable surge in the development of nucleic acid therapeutics and vaccines following the global approval of the two messenger RNA-based COVID-19 vaccines. This growth is fueled by the exploration of numerous RNA products in preclinical stages, offering several advantages over conventional methods, i.e., safety, efficacy, scalability, and cost-effectiveness. In this chapter, we provide an overview of various types of RNA and their mechanisms of action for stimulating immune responses and inducing therapeutic effects. Furthermore, this chapter delves into the varying delivery systems, particularly emphasizing the use of nanoparticles to deliver RNA. The choice of delivery system is an intricate process involved in developing nucleic acid medicines that significantly enhances their stability, biocompatibility, and site-specificity. Additionally, this chapter sheds light on the current landscape of clinical trials of RNA therapeutics and vaccines against intracellular pathogens.