Safety and immunogenicity of a mRNA rabies vaccine in healthy adults: an open-label, non-randomised, prospective, first-in-human phase 1 clinical trial

RNA vaccines: The dawn of a new age for tuberculosis?

Since 2019, there has been a growing focus on mRNA vaccines for infectious disease prevention, particularly following the emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). mRNA vaccines offer advantages such as rapid production and the ability to induce robust cellular and antibody responses, which are essential for combating infections that require cell-mediated immunity, including Tuberculosis (TB). This review explores recent progress in TB mRNA vaccines and addresses several key areas: (1) the urgent need for new TB vaccines; (2) current advancements in TB vaccine development, and the advantages and challenges of mRNA technology; (3) the design and characteristics of TB mRNA vaccines; (4) the immunological mechanisms of TB mRNA vaccines; (5) manufacturing processes for TB mRNA vaccines; and (6) safety and regulatory considerations. This interdisciplinary review aims to provide insights for researchers working to address critical questions in TB mRNA vaccine development.

Intradermal delivery of SARS-CoV-2 RBD3-Fc mRNA vaccines via a needle-free injection system induces robust immune responses in rats

Introduction

Needle-free injection system (NFIS) is easy to operate and can decrease needle phobia. Besides, NFIS can increase the interaction of antigens in a more dispersed manner with immune cell at local injection site, which may improve the immune responses of mRNA vaccines. Although SARS-CoV-2 mRNA vaccines have great success, universal vaccines are urgently needed. Delivering universal mRNA vaccines by NFIS is preferred to combat COVID-19.

Methods

RBD3-Fc mRNA expressing BA.4, Delta, and prototype RBD, and human IgG Fc with YTE mutation was designed and synthesized. The safety and immune responses of universal RBD3-Fc naked mRNA and mRNA-LNP vaccines delivered intradermally using NFIS (named GV-01) and intramuscularly via needles were evaluated and compared in rats.

Results

The prime-boost regimen administered by two routes resulted in potent immune responses and intradermal delivery displays comparable or better performance in terms of binding antibodies, neutralizing antibodies and T cell responses. Naked mRNA vaccines were functional, but less effective than mRNA-LNP vaccines.

Discussion

The above results suggest that RBD3-Fc vaccines are safe and immunogenic and NFIS can be used as an alternative to needles/syringes for the inoculation of mRNA-LNP vaccines to elicit robust systematic immune responses.

Infection and Prevention of Rabies Viruses

Rabies is a fatal zoonotic disease and causes about 59,000 human deaths globally every year. Especially, its mortality is almost 100% in cases where the rabies virus has transmitted to the central nervous system. The special virus life cycle and pathogenic mechanism make it difficult for the host immune system to combat rabies viruses. Vaccination including pre-exposure and post-exposure prophylaxis is an effective strategy for rabies prevention. The pre-exposure vaccination is mainly applied for animals and the post-exposure vaccination is the most application for humans. Although rabies vaccines are widely used and seem to be safe and effective, there are some disadvantages, limitations, or challenges affecting vaccine promotion and distribution. Therefore, more effective, convenient, safer, and cheaper rabies vaccines have been developed or are being developed. The development of novel human rabies vaccine is mainly focusing on vaccines based on a purified Vero cell-cultured freeze-dried rabies vaccine (PVRV). PVRV has been demonstrated to be promising to make the rabies vaccine more effective and secure in animal studies or clinical trials. Moreover, mRNA-based vaccines have been shown to have the potential to enhance the safety and efficacy of rabies vaccines for both animal and human uses.

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.

Jet Injection of Naked mRNA Encoding the RBD of the SARS-CoV-2 Spike Protein Induces a High Level of a Specific Immune Response in Mice

Background: Although mRNA vaccines encapsulated in lipid nanoparticles (LNPs) have demonstrated a safety profile with minimal serious adverse events in clinical trials, there is opportunity to further reduce mRNA reactogenicity. The development of naked mRNA vaccines could improve vaccine tolerability. Naked nucleic acid delivery using the jet injection method may be a solution. Methods: In the first part of the study, the optimal conditions providing low traumatization and high expression of the model mRNA-GFP molecule in the tissues of laboratory animals were determined. Then, we used the selected protocol to immunize BALB/c mice with mRNA-RBD encoding the SARS-CoV-2 receptor-binding domain (RBD). It was demonstrated that mice vaccinated with naked mRNA-RBD developed a high level of specific antibodies with virus-neutralizing activity. The vaccine also induced a strong RBD-specific T-cell response and reduced the viral load in the lungs of the animals after infection with the SARS-CoV-2 virus. The level of immune response in mice immunized with mRNA-RBD using a spring-loaded jet injector was comparable to that in animals immunized with mRNA-RBD encapsulated in LNPs. Results: In this study, the efficacy of an inexpensive, simple, and safe method of mRNA delivery using a spring-loaded jet injector was evaluated and validated. Conclusions: Our findings suggest that the jet injection method may be a possible alternative to LNPs for delivering mRNA vaccines against SARS-CoV-2 infection.

Expanding the Potential of Circular RNA (CircRNA) Vaccines: A Promising Therapeutic Approach

In recent years, circular RNAs (circRNAs) have garnered significant attention due to their unique structure and function, positioning them as promising candidates for next-generation vaccines. The circRNA vaccine, as an RNA vaccine, offers significant advantages in preventing infectious diseases by serving as a vector for protein expression through non-canonical translation. Notably, circRNA vaccines have demonstrated enduring antigenic expression and generate a larger percentage of neutralizing antibodies compared to mRNA vaccines administered at the same dosage. Furthermore, circRNA vaccines can elicit robust cellular and humoral immunity, indicating their potential for tumor vaccine development. However, certain challenges must be addressed to facilitate the widespread use of circRNA vaccines in both infectious disease prevention and tumor treatment. These challenges include the low efficiency of linear RNA circularization, the suboptimal targeting of delivery systems, and the assessment of potential side effects. This work aims to describe the characteristics and functions of circRNAs, elucidate the mechanism behind circRNA vaccines, and discuss their applications in the prevention of infectious diseases and the treatment of tumors, along with their potential future applications.

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.

Elfadl A, Kodama C, Zughaier SM, Farag E, Bansal D. Epidemiology, transmission dynamics, risk factors, and future directions of rabies in the Arabian Peninsula using one health approach: a review

Despite global initiatives to eliminate dog-mediated human rabies by 2030, the Arabian Peninsula faces challenges due to insufficient data. This review addresses the current rabies situation and knowledge gaps in the region and proposes One Health interventions. Employing a mixed-method approach combining scoping and systematic review, the study commenced with a Delphi discussion to identify knowledge gaps and set objectives. The literature search encompassed published articles and grey literature. The spatial and temporal distribution of rabies was analysed, alongside quantitative meta-analyses to assess prevalence. Rabies virus gene sequences from the NCBI database were examined for reservoir hosts and evolutionary patterns. The final Delphi discussion with experts focused on addressing knowledge gaps and formulating One Health interventions. The first reported human rabies case in this region occurred in Saudi Arabia in 1980. Yemen reported the highest number of cases (439), followed by Iraq (249), Saudi Arabia (91), Jordan (14), and Oman (9). Fox bites accounted for the most cases (47.4%), followed by dog (36.8%) and wild animal (15.8%) bites. The virus was detected in at least 21 animal species. Phylogenetic analysis detected a single strain with two clades, with foxes being the primary virus reservoir. However, the experts expressed scepticism about the accuracy of rabies reports in scientific literature. To achieve the 2030 goal of eliminating dog-mediated human rabies, a stepwise approach towards rabies elimination assessment is crucial in the region. Enhanced surveillance, awareness campaigns, and access to post exposure prophylaxis are essential to address the disease burden.

Decoding trends in mRNA vaccine research: A comprehensive bibliometric study

BACKGROUND

In recent years, infectious diseases like COVID-19 have had profound global socio-economic impacts. mRNA vaccines have gained prominence due to their rapid development, industrial adaptability, simplicity, and responsiveness to new variants. Notably, the 2023 Nobel Prize in Physiology or Medicine recognized significant contributions to mRNA vaccine research.

METHODS

Our study employed a comprehensive bibliometric analysis using the Web of Science Core Collection (WoSCC) database, encompassing 5,512 papers on mRNA vaccines from 2003 to 2023. We generated cooperation maps, co-citation analyses, and keyword clustering to evaluate the field's developmental history and achievements.

RESULTS

The analysis yielded knowledge maps highlighting countries/institutions, influential authors, frequently published and highly cited journals, and seminal references. Ongoing research hotspots encompass immune responses, stability enhancement, applications in cancer prevention and treatment, and combating infectious diseases using mRNA technology.

CONCLUSIONS

mRNA vaccines represent a transformative development in infectious disease prevention. This study provides insights into the field's growth and identifies key research priorities, facilitating advancements in vaccine technology and addressing future challenges.

Development of mRNA rabies vaccines

Rabies, primarily transmitted to humans by dogs (accounting for 99% of cases). Once rabies occurs, its mortality rate is approximately 100%. Post-exposure prophylaxis (PEP) is critical for preventing the onset of rabies after exposure to rabid animals, and vaccination is a pivotal element of PEP. However, high costs and complex immunization protocols have led to poor adherence to rabies vaccinations. Consequently, there is an urgent need to develop new rabies vaccines that are safe, highly immunogenic, and cost-effective to improve compliance and effectively prevent rabies. In recent years, mRNA vaccines have made significant progress in the structural modification and optimization of delivery systems. Various mRNA vaccines are currently undergoing clinical trials, positioning them as viable alternatives to the traditional rabies vaccines. In this article, we discuss a novel mRNA rabies vaccine currently undergoing clinical and preclinical testing, and evaluate its potential to replace existing vaccines.

Multimodal profiling of biostabilized human skin modules reveals a coordinated ecosystem response to injected mRNA-1273 COVID-19 vaccine

BACKGROUND

The field of drug development is witnessing a remarkable surge in the development of innovative strategies. There is a need to develop technological platforms capable of generating human data prior to progressing to clinical trials.

METHODS

Here we introduce a new flexible solution designed for the comprehensive monitoring of the natural human skin ecosystem's response to immunogenic drugs over time. Based on unique bioengineering to preserve surgical resections in a long survival state, it allows for the first time a comprehensive analysis of resident immune cells response at both organ and single-cell levels.

RESULTS

Upon injection of the mRNA-1273 COVID-19 vaccine, we characterized precise sequential molecular events triggered upon detection of the exogenous substance. The vaccine consistently targets DC/macrophages and mast cells, regardless of the administration route, while promoting specific cell-cell communications in surrounding immune cell subsets.

CONCLUSION

Given its direct translational relevance, this approach provides a multiscale vision of genuine human tissue immunity that could pave the way toward the development of new vaccination and drug development strategies.

A nucleoside-modified mRNA vaccine forming rabies virus-like particle elicits strong cellular and humoral immune responses against rabies virus infection in mice

Rabies is a lethal zoonotic disease that threatens human health. As the only viral surface protein, the rabies virus (RABV) glycoprotein (G) induces main neutralizing antibody (Nab) responses; however, Nab titre is closely correlated with the conformation of G. Virus-like particles (VLP) formed by the co-expression of RABV G and matrix protein (M) improve retention and antigen presentation, inducing broad, durable immune responses. RABV nucleoprotein (N) can elicit humoral and cellular immune responses. Hence, we developed a series of nucleoside-modified RABV mRNA vaccines encoding wild-type G, soluble trimeric RABV G formed by an artificial trimer motif (tG-MTQ), membrane-anchored prefusion-stabilized G (preG). Furthermore, we also developed RABV VLP mRNA vaccine co-expressing preG and M to generate VLPs, and VLP/N mRNA vaccine co-expressing preG, M, and N. The RABV mRNA vaccines induced higher humoral and cellular responses than inactivated rabies vaccine, and completely protected mice against intracerebral challenge. Additionally, the IgG and Nab titres in RABV preG, VLP and VLP/N mRNA groups were significantly higher than those in G and tG-MTQ groups. A single administration of VLP or VLP/N mRNA vaccines elicited protective Nab responses, the Nab titres were significantly higher than that in inactivated rabies vaccine group at day 7. Moreover, RABV VLP and VLP/N mRNA vaccines showed superior capacities to elicit potent germinal centre, long-lived plasma cell and memory B cell responses, which linked to high titre and durable Nab responses. In summary, our data demonstrated that RABV VLP and VLP/N mRNA vaccines could be promising candidates against rabies.

Bioinformatics analysis to design a multi-epitope mRNA vaccine against S. agalactiae exploiting pathogenic proteins

Antibiotic resistance in bacterial pathogen infections is a growing global issue that occurs due to their adaptation to changing environmental conditions. Therefore, producing an efficient vaccine as an alternative approach can improve the immune system, eradicate related pathogens, and overcome this growing problem. Streptococcus agalactiae belongs to group B Streptococcus (GBS). Colonization of GBS during pregnancy is a significant risk factor for infants and young children. S. agalactiae infected population exhibits resistance to beta-lactams, including penicillin and the second-line antibiotics erythromycin and clindamycin. On the other hand, there are currently no commercial vaccines against this pathogen. Vaccination of pregnant women is a highly effective method to protect newborns and infants from S. agalactiae infection, and it has been identified as an urgent demand by the World Health Organization. This study employed various immunoinformatic tools to develop an effective vaccine that could trigger both humoral and cell-mediated immunity and prevent disease. For this purpose, three conserved antigenic proteins of the main pathogenic strains of S. agalactiae were utilized to predict CTL, HTL, and B-cell epitopes for producing an mRNA vaccine against different strains of S. agalactiae. The selected epitopes were fused using proper linkers. The Resuscitation promoting factor E (RpfE) sequence was incorporated in the designed vaccine construct as an adjuvant to boost its immune response. Different physicochemical characteristics of the final designed vaccine, modeling of the three-dimensional structure, molecular docking, molecular dynamics simulation, and immunological response simulation were screened following vaccine administration in an in vivo model. Computational immune simulation data identified that IgG1, IgM, INF γ, IL-2, T helper, and B-cell populations increased significantly after vaccination. These findings suggested that the vaccine candidate may provide good protection against S. agalactiae infection. However, experimental and animal model studies are required for additional validation and implementation in human vaccination programs.

IL-7 promotes mRNA vaccine-induced long-term immunity

Messenger RNA (mRNA) vaccines are a key technology in combating existing and emerging infectious diseases. However, improving the immunogenicity and durability of mRNA vaccines remains a challenge. To elicit optimal immune responses, integrating antigen-encoded mRNA and immunostimulatory adjuvants into a single formulation is a promising approach to enhancing the efficacy of mRNA vaccines. Here, we report an adjuvant strategy to enhance the efficacy of mRNA vaccines by co-loading mRNA encoding the antigen (rabies virus glycoprotein, RABV-G) and mRNA encoding IL-7 into lipid nanoparticles, achieving co-delivery to the same antigen-presenting cells. A single immunization with G&IL-7 mRNA vaccine elicited robust humoral immune responses in mice and conferred complete protection against RABV challenge. Notably, the high levels of neutralizing antibody induced by the G&IL-7 mRNA vaccine were maintained for at least 6 months, providing mice with long-term significant and complete protection against RABV. Additionally, IL-7 also enhanced antibody responses against the SARS-CoV-2. These data demonstrate that IL-7 is a potent mRNA vaccine adjuvant that can provide the required immune stimulation in various mRNA vaccine formulations.

Progress and prospects of mRNA-based drugs in pre-clinical and clinical applications

In the last decade, messenger ribonucleic acid (mRNA)-based drugs have gained great interest in both immunotherapy and non-immunogenic applications. This surge in interest can be largely attributed to the demonstration of distinct advantages offered by various mRNA molecules, alongside the rapid advancements in nucleic acid delivery systems. It is noteworthy that the immunogenicity of mRNA drugs presents a double-edged sword. In the context of immunotherapy, extra supplementation of adjuvant is generally required for induction of robust immune responses. Conversely, in non-immunotherapeutic scenarios, immune activation is unwanted considering the host tolerability and high expression demand for mRNA-encoded functional proteins. Herein, mainly focused on the linear non-replicating mRNA, we overview the preclinical and clinical progress and prospects of mRNA medicines encompassing vaccines and other therapeutics. We also highlight the importance of focusing on the host-specific variations, including age, gender, pathological condition, and concurrent medication of individual patient, for maximized efficacy and safety upon mRNA administration. Furthermore, we deliberate on the potential challenges that mRNA drugs may encounter in the realm of disease treatment, the current endeavors of improvement, as well as the application prospects for future advancements. Overall, this review aims to present a comprehensive understanding of mRNA-based therapies while illuminating the prospective development and clinical application of mRNA drugs.

The current status and development forecasts of vaccines for aquaculture and its effects on bacterial and viral diseases

The aquaculture sector predicts protein-rich meals by 2040 and has experienced significant economic shifts since 2000. However, challenges emanating from disease control measures, brood stock improvement, feed advancements, hatchery technology, and water quality management due to environmental fluctuations have been taken as major causative agents for hindering the sector's growth. For the past years, aquatic disease prevention and control have principally depended on the use of various antibiotics, ecologically integrated control, other immunoprophylaxis mechanisms, and chemical drugs, but the long-term use of chemicals such as antibiotics not only escalates antibiotic-resistant bacteria and genes but also harms the fish and the environments, resulting in drug residues in aquatic products, severely obstructing the growth of the aquaculture sector. The field of science has opened new avenues in basic and applied research for creating and producing innovative and effective vaccines and the enhancement of current vaccines to protect against numerous infectious diseases. Recent advances in vaccines and vaccinology could lead to novel vaccine candidates that can tackle fish diseases, including parasitic organism agents, for which the current vaccinations are inadequate. In this review, we study and evaluate the growing aquaculture production by focusing on the current knowledge, recent progress, and prospects related to vaccinations and immunizations in the aquaculture industry and their effects on treating bacterial and viral diseases. The subject matter covers a variety of vaccines, such as conventional inactivated and attenuated vaccines as well as advanced vaccines, and examines their importance in real-world aquaculture scenarios. To encourage enhanced importation of vaccines for aquaculture sustainability and profitability and also help in dealing with challenges emanating from diseases, national and international scientific and policy initiatives need to be informed about the fundamental understanding of vaccines.

A comprehensive investigation of Glycoprotein-based nucleic acid vaccines for Hantaan Virus

Hemorrhagic fever with renal syndrome (HFRS) occurs throughout Eurasia with considerable morbidity and mortality. Currently, the absence of specific treatments or effective antiviral drugs for hantavirus infection makes developing safe and effective vaccines a high priority. Here, we report the development of three novel nucleic acid vaccine candidates, mRNA, naked DNA, and DNA encapsulated in lipid nanoparticles, encoding the glycoproteins of the Hantaan virus (HTNV). To comprehensively evaluate the potential of candidate HTNV nucleic acid vaccines in preventing HFRS, we focus on evaluating their immunogenicity and efficacy in mice and comparing them with an inactivated vaccine as the benchmark. Our findings reveal that all candidate vaccines activated instant and sustained immune responses, offering comparable in vivo protective efficacy to the inactivated vaccines. Notably, compared to the inactivated vaccine, mRNA vaccine induced stronger virus-specific T-helper 1 cell immune response, while DNA-LNP elicited higher levels of neutralizing antibodies in mice. These results mark a significant step in developing nucleic acid vaccines for HTNV, suggesting that sequential immunization with DNA and mRNA vaccines could further amplify the advantages of nucleic acid vaccines.

Virulence and Immune Evasion Strategies of FMDV: Implications for Vaccine Design

Foot-and-mouth disease (FMD) is globally recognized as a highly economically devastating and prioritized viral disease affecting livestock. Vaccination remains a crucial preventive measure against FMD. The improvement of current vaccine platforms could help control outbreaks, leading to the potential eradication of the disease. In this review, we describe the variances in virulence and immune responses among FMD-susceptible host species, specifically bovines and pigs, highlighting the details of host-pathogen interactions and their impact on the severity of the disease. This knowledge serves as an important foundation for translating our insights into the rational design of vaccines and countermeasure strategies, including the use of interferon as a biotherapeutic agent. Ultimately, in this review, we aim to bridge the gap between our understanding of FMDV biology and the practical approaches to control and potentially eradicate FMD.

Preformed Vesicle Approach to LNP Manufacturing Enhances Retinal mRNA Delivery

Complete encapsulation of nucleic acids by lipid-based nanoparticles (LNPs) is often thought to be one of the main prerequisites for successful nucleic acid delivery, as the lipid environment protects mRNA from degradation by external nucleases and assists in initiating delivery processes. However, delivery of mRNA via a preformed vesicle approach (PFV-LNPs) defies this precondition. Unlike traditional LNPs, PFV-LNPs are formed via a solvent-free mixing process, leading to a superficial mRNA localization. While demonstrating low encapsulation efficiency in the RiboGreen assay, PFV-LNPs improved delivery of mRNA to the retina by up to 50% compared to the LNP analogs across several benchmark formulations, suggesting the utility of this approach regardless of the lipid composition. Successful mRNA and gene editors' delivery is observed in the retinal pigment epithelium and photoreceptors and validated in mice, non-human primates, and human retinal organoids. Deploying PFV-LNPs in gene editing experiments result in a similar extent of gene editing compared to analogous LNP (up to 3% on genomic level) in the Ai9 reporter mouse model; but, remarkably, retinal tolerability is significantly improved for PFV-LNP treatment. The study findings indicate that the LNP formulation process can greatly influence mRNA transfection and gene editing outcomes, improving LNP treatment safety without sacrificing efficacy.

Advancing mRNA Therapeutics: The Role and Future of Nanoparticle Delivery Systems

The coronavirus (COVID-19) pandemic has underscored the critical role of mRNA-based vaccines as powerful, adaptable, readily manufacturable, and safe methodologies for prophylaxis. mRNA-based treatments are emerging as a hopeful avenue for a plethora of conditions, encompassing infectious diseases, cancer, autoimmune diseases, genetic diseases, and rare disorders. Nonetheless, the in vivo delivery of mRNA faces challenges due to its instability, suboptimal delivery, and potential for triggering undesired immune reactions. In this context, the development of effective drug delivery systems, particularly nanoparticles (NPs), is paramount. Tailored with biophysical and chemical properties and susceptible to surface customization, these NPs have demonstrated enhanced mRNA delivery in vivo and led to the approval of several NPs-based formulations for clinical use. Despite these advancements, the necessity for developing a refined, targeted NP delivery system remains imperative. This review comprehensively surveys the biological, translational, and clinical progress in NPs-mediated mRNA therapeutics for both the prevention and treatment of diverse diseases. By addressing critical factors for enhancing existing methodologies, it aims to inform the future development of precise and efficacious mRNA-based therapeutic interventions.

Immunoinformatic-guided novel mRNA vaccine designing to elicit immunogenic responses against the endemic Monkeypox virus

Monkeypox virus (MPXV) is an orthopoxvirus, causing zoonotic infections in humans with smallpox-like symptoms. The WHO reported MPXV cases in May 2022 and the outbreak caused significant morbidity threats to immunocompromised individuals and children. Currently, no clinically validated therapies are available against MPXV infections. The present study is based on immunoinformatics approaches to design mRNA-based novel vaccine models against MPXV. Three proteins were prioritized based on high antigenicity, low allergenicity, and toxicity values to predict T- and B-cell epitopes. Lead T- and B-cell epitopes were used to design vaccine constructs, linked with epitope-specific linkers and adjuvant to enhance immune responses. Additional sequences, including Kozak sequence, MITD sequence, tPA sequence, Goblin 5', 3' UTRs, and a poly(A) tail were added to design stable and highly immunogenic mRNA vaccine construct. High-quality structures were predicted by molecular modeling and 3D-structural validation of the vaccine construct. Population coverage and epitope-conservancy speculated broader protection of designed vaccine model against multiple MPXV infectious strains. MPXV-V4 was eventually prioritized based on its physicochemical and immunological parameters and docking scores. Molecular dynamics and immune simulations analyses predicted significant structural stability and binding affinity of the top-ranked vaccine model with immune receptors to elicit cellular and humoral immunogenic responses against the MPXV. The pursuance of experimental and clinical follow-up of these prioritized constructs may lay the groundwork to develop safe and effective vaccine against MPXV.Communicated by Ramaswamy H. Sarma.

A combination influenza mRNA vaccine candidate provided broad protection against diverse influenza virus challenge

Influenza viruses present a significant threat to global health. The production of a universal vaccine is considered essential due to the ineffectiveness of current seasonal influenza vaccines against mutant strains. mRNA technology offers new prospects in vaccinology, with various candidates for different infectious diseases currently in development and testing phases. In this study, we encapsulated a universal influenza mRNA vaccine. The vaccine encoded influenza hemagglutinin (HA), nucleoprotein (NP), and three tandem repeats of matrix protein 2 (3M2e). Twice-vaccinated mice exhibited strong humoral and cell-mediated immune responses in vivo. Notably, these immune responses led to a significant reduction in viral load of the lungs in challenged mice, and also conferred protection against future wild-type H1N1, H3N2, or H5N1 influenza virus challenges. Our findings suggest that this mRNA-universal vaccine strategy for influenza virus may be instrumental in mitigating the impact of future influenza pandemics.

Safety and efficacy assessment of an mRNA rabies vaccine in dogs, rodents, and cynomolgus macaques

Rabies is a lethal disease caused by the rabies virus (RABV), which causes acute neurological infections in mammals, including human beings. We previously reported that an mRNA vaccine (LVRNA001) encoding the rabies virus's glycoprotein induced strong protective immune responses to rabies in mice and dogs. Here, we further evaluate the safety of LVRNA001. First, we performed a confirmative efficacy study in dogs, which showed that LVRNA001 fully protected the animals from the virus, both pre- and post-infection. Moreover, using pre- and post-exposure prophylaxis murine models, we showed that LVRNA001, built from the CTN-1 strain, was able to protect against various representative RABV strains from the China I-VII clades. To evaluate the safety of the vaccine, chronic and reproductive toxicity studies were performed with cynomolgus macaques and rats, respectively. In a repeated-dose chronic toxicity study, vaccinated monkeys displayed no significant alterations in body weight, temperature, or hematological and biochemical markers. Lymphocyte subset measurement and histopathological examination showed that no toxicity was associated with the vaccine. The immunogenicity study in cynomolgus macaques demonstrated that LVRNA001 promoted the generation of neutralizing antibodies and Th1-biased immune response. Evaluation of reproductive toxicity in rats revealed that administration of LVRNA001 had no significant effects on fertility, maternal performance, reproductive processes, and postnatal outcomes. In conclusion, LVRNA001 can provide efficient protection against rabies virus infection in dogs and mice, and toxicity studies showed no significant vaccine-related adverse effects, suggesting that LVRNA001 is a promising and safe vaccine candidate for rabies prophylaxis and therapy.

Emerging mRNA Technology for Liver Disease Therapy

Liver diseases have consistently posed substantial challenges to global health. It is crucial to find innovative methods to effectively prevent and treat these diseases. In recent times, there has been an increasing interest in the use of mRNA formulations that accumulate in liver tissue for the treatment of hepatic diseases. In this review, we start by providing a detailed introduction to the mRNA technology. Afterward, we highlight types of liver diseases, discussing their causes, risks, and common therapeutic strategies. Additionally, we summarize the latest advancements in mRNA technology for the treatment of liver diseases. This includes systems based on hepatocyte growth factor, hepatitis B virus antibody, left-right determination factor 1, human hepatocyte nuclear factor α, interleukin-12, methylmalonyl-coenzyme A mutase, etc. Lastly, we provide an outlook on the potential of mRNA technology for the treatment of liver diseases, while also highlighting the various technical challenges that need to be addressed. Despite these difficulties, mRNA-based therapeutic strategies may change traditional treatment methods, bringing hope to patients with liver diseases.

Quality Control of mRNA Vaccines by Synthetic Ribonucleases: Analysis of the Poly-A-Tail

The effectivity and safety of mRNA vaccines critically depends on the presence of correct 5' caps and poly-A tails. Due to the high molecular mass of full-size mRNAs, however, the direct analysis by mass spectrometry is hardly possible. Here we describe the use of synthetic ribonucleases to cleave off 5' and 3' terminal fragments which can be further analyzed by HPLC or by LC-MS. Compared to existing methods (e. g. RNase H), the new approach uses robust catalysts, is free of sequence limitations, avoids metal ions and combines fast sample preparation with high precision of the cut.

Lipid Nanocarrier-Based mRNA Therapy: Challenges and Promise for Clinical Transformation

Due to the outbreak of novel coronavirus pneumonia, messenger RNA (mRNA) technology has attracted heated attention. A specific, safe, and efficient mRNA delivery system is needed. Lipid nanocarriers have become attractive carriers for mRNA delivery due to their high delivery efficiency, few side effects, and easy modification to change their structures and functions. To achieve the desired biological effect, lipid nanocarriers must reach the designated location for effective drug delivery. Therefore, the effects of the composition of lipid nanocarriers on their key properties are briefly reviewed. In addition, the progress of smart drug delivery by changing the composition of lipid nanocarriers is summarized, and the importance of component design and structure is emphasized. Subsequently, this review summarizes the latest progress in lipid nanocarrier-based mRNA technology and provides corresponding strategies for its current challenges, putting forward valuable information for the future design of lipid nanocarriers and mRNA.

A comprehensive comparison of DNA and RNA vaccines

Nucleic acid technology has revolutionized vaccine development, enabling rapid design and production of RNA and DNA vaccines for prevention and treatment of diseases. The successful deployment of mRNA and plasmid DNA vaccines against COVID-19 has further validated the technology. At present, mRNA platform is prevailing due to its higher efficacy, while DNA platform is undergoing rapid evolution because it possesses unique advantages that can potentially overcome the problems associated with the mRNA platform. To help understand the recent performances of the two vaccine platforms and recognize their clinical potentials in the future, this review compares the advantages and drawbacks of mRNA and DNA vaccines that are currently known in the literature, in terms of development timeline, financial cost, ease of distribution, efficacy, safety, and regulatory approval of products. Additionally, the review discusses the ongoing clinical trials, strategies for improvement, and alternative designs of RNA and DNA platforms for vaccination.

Emerging advances in delivery systems for mRNA cancer vaccines

The success of lipid nanoparticles (LNPs) in treating COVID-19 promotes further research of mRNA vaccines for cancer vaccination. Aiming at overcoming the constraints of currently available mRNA carriers, various alternative nano-vectors have been developed for delivering tumor antigen encoding mRNA and showed versatility to induce potent anti-tumor immunity. The rationally designed nano-vaccines increase the immune activation capacity of the mRNA vaccines by promoting crucial aspects including mRNA stability, cellular uptake, endosomal escape and targeting of immune cells or organs. Herein, we summarized the research progress of various mRNA based nano-vaccines that have been reported for cancer vaccination, including LNPs, lipid enveloped hybrid nanoparticles, polymeric nanoparticles etc. Several strategies that have been reported for further enhancing the immune stimulation efficacy of mRNA nano-vaccines, including developing nano-vaccines for co-delivering adjuvants, combination of immune checkpoint inhibitors, and optimizing the injection routes for boosting immune responses, have been reviewed. The progress of mRNA nano-vaccines in clinical trials and the prospect of the mRNA vaccines for cancer vaccination are also discussed.

Efficient signal sequence of mRNA vaccines enhances the antigen expression to expand the immune protection against viral infection

The signal sequence played a crucial role in the efficacy of mRNA vaccines against virus pandemic by influencing antigen translation. However, limited research had been conducted to compare and analyze the specific mechanisms involved. In this study, a novel approach was introduced by substituting the signal sequence of the mRNA antigen to enhance its immune response. Computational simulations demonstrated that various signal peptides differed in their binding capacities with the signal recognition particle (SRP) 54 M subunit, which positively correlated with antigen translation efficiency. Our data revealed that the signal sequences of tPA and IL-6-modified receptor binding domain (RBD) mRNA vaccines sequentially led to higher antigen expression and elicited more robust humoral and cellular immune protection against the SARS-CoV-2 compared to the original signal sequence. By highlighting the importance of the signal sequence, this research provided a foundational and safe approach for ongoing modifications in signal sequence-antigen design, aiming to optimize the efficacy of mRNA vaccines.

mRNA vaccines against infectious diseases and future direction

Vaccines are used for the control of infectious diseases of animals. Over other types of vaccinations like live attenuated or killed vaccines, mRNA-based vaccines have significant advantages. As only a small portion of the pathogen's genetic material is employed and the dose rate of mRNA-based vaccines is low, there is the least possibility that the pathogen will reverse itself. A carrier or vehicle that shields mRNA-based vaccines from the host's cellular RNases is necessary for their delivery. mRNA vaccines have been shown to be effective and to induce both a cell-mediated immune response and a humoral immune response in clinical trials against various infectious diseases (viral and parasitic) affecting the animals, including rabies, foot and mouth disease, toxoplasmosis, Zikavirus, leishmaniasis, and COVID-19. The current review aims to highlight the use of mRNA-based vaccines both in viral and parasitic diseases of animals.

Map conformational landscapes of intrinsically disordered proteins with polymer physics quantities

Disordered proteins are conformationally flexible proteins that are biologically important and have been implicated in devastating diseases such as Alzheimer's disease and cancer. Unlike stably folded structured proteins, disordered proteins sample a range of different conformations that needs to be accounted for. Here, we treat disordered proteins as polymer chains, and compute a dimensionless quantity called instantaneous shape ratio (Rs), as Rs = Ree2/Rg2, where Ree is end-to-end distance and Rg is radius of gyration. Extended protein conformations tend to have high Ree compared with Rg, and thus have high Rs values, whereas compact conformations have smaller Rs values. We use a scatter plot of Rs (representing shape) against Rg (representing size) as a simple map of conformational landscapes. We first examine the conformational landscape of simple polymer models such as Random Walk, Self-Avoiding Walk, and Gaussian Walk (GW), and we notice that all protein/polymer maps lie within the boundaries of the GW map. We thus use the GW map as a reference and, to assess conformational diversity, we compute the fraction of the GW conformations (fC) covered by each protein/polymer. Disordered proteins all have high fC scores, consistent with their disordered nature. Each disordered protein accesses a different region of the reference map, revealing differences in their conformational ensembles. We additionally examine the conformational maps of the nonviral gene delivery vector polyethyleneimine at various protonation states, and find that they resemble disordered proteins, with coverage of the reference map decreasing with increasing protonation state, indicating decreasing conformational diversity. We propose that our method of combining Rs and Rg in a scatter plot generates a simple, meaningful map of the conformational landscape of a disordered protein, which in turn can be used to assess conformational diversity of disordered proteins.

Delivery of Experimental mRNA Vaccine Encoding the RBD of SARS-CoV-2 by Jet Injection

We studied a needle-free jet injection delivery of an experimental mRNA vaccine encoding the receptor-binding domain of the SARS-CoV-2 S protein (mRNA-RBD). Immunization of BALB/c mice with mRNA-RBD by a needle-free jet injector induced high levels of antibodies with virus-neutralizing activity and a virus-specific T-cell response. The immune response was low in the group of mice that received intramuscular injection of mRNA-RBD. The effectiveness of this simple and safe method of mRNA delivering has been demonstrated. Thus, jet injection of mRNA vaccine can be a good alternative to lipid nanoparticles.

Strategies for non-viral vectors targeting organs beyond the liver

In recent years, nanoparticles have evolved to a clinical modality to deliver diverse nucleic acids. Rising interest in nanomedicines comes from proven safety and efficacy profiles established by continuous efforts to optimize physicochemical properties and endosomal escape. However, despite their transformative impact on the pharmaceutical industry, the clinical use of non-viral nucleic acid delivery is limited to hepatic diseases and vaccines due to liver accumulation. Overcoming liver tropism of nanoparticles is vital to meet clinical needs in other organs. Understanding the anatomical structure and physiological features of various organs would help to identify potential strategies for fine-tuning nanoparticle characteristics. In this Review, we discuss the source of liver tropism of non-viral vectors, present a brief overview of biological structure, processes and barriers in select organs, highlight approaches available to reach non-liver targets, and discuss techniques to accelerate the discovery of non-hepatic therapies.

Engineered mRNA Delivery Systems for Biomedical Applications

Messenger RNA (mRNA)-based therapeutic strategies have shown remarkable promise in preventing and treating a staggering range of diseases. Optimizing the structure and delivery system of engineered mRNA has greatly improved its stability, immunogenicity, and protein expression levels, which has led to a wider range of uses for mRNA therapeutics. Herein, a thorough analysis of the optimization strategies used in the structure of mRNA is first provided and delivery systems are described in great detail. Furthermore, the latest advancements in biomedical engineering for mRNA technology, including its applications in combatting infectious diseases, treating cancer, providing protein replacement therapy, conducting gene editing, and more, are summarized. Lastly, a perspective on forthcoming challenges and prospects concerning the advancement of mRNA therapeutics is offered. Despite these challenges, mRNA-based therapeutics remain promising, with the potential to revolutionize disease treatment and contribute to significant advancements in the biomedical field.

mRNA-based therapeutics: looking beyond COVID-19 vaccines

Recent advances in mRNA technology and its delivery have enabled mRNA-based therapeutics to enter a new era in medicine. The rapid, potent, and transient nature of mRNA-encoded proteins, without the need to enter the nucleus or the risk of genomic integration, makes them desirable tools for treatment of a range of diseases, from infectious diseases to cancer and monogenic disorders. The rapid pace and ease of mass-scale manufacturability of mRNA-based therapeutics supported the global response to the COVID-19 pandemic. Nonetheless, challenges remain with regards to mRNA stability, duration of expression, delivery efficiency, and targetability, to broaden the applicability of mRNA therapeutics beyond COVID-19 vaccines. By learning from the rapidly expanding preclinical and clinical studies, we can optimise the mRNA platform to meet the clinical needs of each disease. Here, we will summarise the recent advances in mRNA technology; its use in vaccines, immunotherapeutics, protein replacement therapy, and genomic editing; and its delivery to desired specific cell types and organs for development of a new generation of targeted mRNA-based therapeutics.

The Role of Biological Sex in Pre-Clinical (Mouse) mRNA Vaccine Studies

In this study, we consider the influence of biological sex-specific immune responses on the assessment of mRNA vaccines in pre-clinical murine studies. Recognising the established disparities in immune function attributed to genetic and hormonal differences between individuals of different biological sexes, we compared the mRNA expression and immune responses in mice of both biological sexes after intramuscular injection with mRNA incorporated within lipid nanoparticles. Regarding mRNA expression, no significant difference in protein (luciferase) expression at the injection site was observed between female and male mice following intramuscular administration; however, we found that female BALB/c mice exhibit significantly greater total IgG responses across the concentration range of mRNA lipid nanoparticles (LNPs) in comparison to their male counterparts. This study not only contributes to the scientific understanding of mRNA vaccine evaluation but also emphasizes the importance of considering biological sex in vaccine study designs during pre-clinical evaluation in murine studies.

A rabies mRNA vaccine with H270P mutation in its glycoprotein induces strong cellular and humoral immunity

Rabies is a lethal zoonotic disease that kills approximately 60,000 people each year. As the sole virion-surface protein, the rabies virus glycoprotein (RABV-G) mediates its host-cell entry. RABV-G's pre-fusion conformation displays major known neutralizing antibody epitopes, which can be used as immunogen for prophylaxis. H270P targeted mutation can stabilize RABV-G in the pre-fusion conformation. Herein, we report the development of a highly promising rabies mRNA vaccine composed of H270P targeted mutation packaged in lipid nanoparticle (LNP), named LNP-mRNA-G-H270P. Humoral and cellular immunity of this vaccine were assessed in mice comparing to the unmodified LNP-mRNA-G and a commercially available inactivated vaccine using one-way analysis of variance (ANOVA) followed by Dunnett's multiple comparisons test. The results show the titer of RABV-G-specific IgG and virus-neutralization antibody titers (VNTs) in LNP-mRNA-G-H270P group were significant higher than those in LNP-mRNA-G and inactivated vaccine groups. Likewise, IFN-γ-secreting splenocytes, level of IL-2 in the supernatant of spleen cells, as well as IFN-γ-producing CD4+ T cells in LNP-mRNA-G-H270P group were significant higher than those in the other two vaccine groups. Hence, these results demonstrated that targeting the H270P mutation in RABV-G through an mRNA-LNP vaccine platform represents a promising strategy for developing a more efficacious rabies vaccine.

Vaccine Molecule Design Based on Phage Display and Computational Modeling against Rhabdovirus

Rhabdoviruses with rich species lead a variety of high lethality and rapid transmission diseases to plants and animals around the globe. Vaccination is one of the most effective approaches to prevent and control virus disease. However, the key antigenic epitopes of glycoprotein being used for vaccine development are unclear. In this study, fish-derived Abs are employed for a Micropterus salmoides rhabdovirus (MSRV) vaccine design by phage display and bioinformatics analysis. We constructed an anti-MSRV phage Ab library to screen Abs for glycoprotein segment 2 (G2) (G129-266). Four M13-phage-displayed Abs (Ab-5, Ab-7, Ab-8 and Ab-30) exhibited strong specificity to target Ag, and Ab-7 had the highest affinity with MSRV. Ab-7 (300 μg/ml) significantly increased grass carp ovary cell viability to 83.40% and significantly decreased the titer of MSRV. Molecular docking results showed that the key region of Ag-Ab interaction was located in 10ESQEFTTLTSH20 of G2. G2Ser11 and G2Gln12 were replaced with alanine, respectively, and molecular docking results showed that the Ag-Ab was nonbinding (ΔG > 0). Then, the peptide vaccine KLH-G210-20 was immunized to M. salmoides via i.p. injection. ELISA result showed that the serum Ab potency level increased significantly (p < 0.01). More importantly, the challenge test demonstrated that the peptide vaccine elicited robust protection against MSRV invasion, and the relative percentage survival reached 62.07%. Overall, this study proposed an approach for screening key epitope by combining phage display technology and bioinformatics tools to provide a reliable theoretical reference for the prevention and control of viral diseases.

Toward low-cost gene therapy: mRNA-based therapeutics for treatment of inherited retinal diseases

Inherited retinal diseases (IRDs) stem from genetic mutations that result in vision impairment. Gene therapy shows promising therapeutic potential, exemplified by the encouraging initial results with voretigene neparvovec. Nevertheless, the associated costs impede widespread access, particularly in low-to-middle income countries. The primary challenge remains: how can we make these therapies globally affordable? Leveraging advancements in mRNA therapies might offer a more economically viable alternative. Furthermore, transitioning to nonviral delivery systems could provide a dual benefit of reduced costs and increased scalability. Relevant stakeholders must collaboratively devise and implement a research agenda to realize the potential of mRNA strategies in equitable access to treatments to prevent vision loss.

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.

Safety, Immunogenicity, and Mechanism of a Rotavirus mRNA-LNP Vaccine in Mice

Rotaviruses (RVs) are a major cause of diarrhea in young children worldwide. The currently available and licensed vaccines contain live attenuated RVs. Optimization of live attenuated RV vaccines or developing non-replicating RV (e.g., mRNA) vaccines is crucial for reducing the morbidity and mortality from RV infections. Herein, a nucleoside-modified mRNA vaccine encapsulated in lipid nanoparticles (LNP) and encoding the VP7 protein from the G1 type of RV was developed. The 5' untranslated region of an isolated human RV was utilized for the mRNA vaccine. After undergoing quality inspection, the VP7-mRNA vaccine was injected by subcutaneous or intramuscular routes into mice. Mice received three injections in 21 d intervals. IgG antibodies, neutralizing antibodies, cellular immunity, and gene expression from peripheral blood mononuclear cells were evaluated. Significant differences in levels of IgG antibodies were not observed in groups with adjuvant but were observed in groups without adjuvant. The vaccine without adjuvant induced the highest antibody titers after intramuscular injection. The vaccine elicited a potent antiviral immune response characterized by antiviral clusters of differentiation CD8+ T cells. VP7-mRNA induced interferon-γ secretion to mediate cellular immune responses. Chemokine-mediated signaling pathways and immune response were activated by VP7-mRNA vaccine injection. The mRNA LNP vaccine will require testing for protective efficacy, and it is an option for preventing rotavirus infection.

RNA therapeutics for infectious diseases

Ribonucleic acids (RNAs), including the messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), play important roles in living organisms and viruses. In recent years, the RNA-based technologies including the RNAs inhibiting other RNA activities, the RNAs targeting proteins, the RNAs reprograming genetic information, and the RNAs encoding therapeutical proteins, are useful methods to apply in prophylactic and therapeutic vaccines. In this review, we summarize and highlight the current application of the RNA therapeutics, especially on mRNA vaccines which have potential for prevention and treatment against human and animal infectious diseases.

RNA therapeutics: Molecular mechanisms, and potential clinical translations

RNA therapies involve the utilization of natural and artificial RNA molecules to control the expression and function of cellular genes and proteins. Initializing from 1990s, RNA therapies now show the rapid growth in the development and application of RNA therapeutics for treating various conditions, especially for undruggable diseases. The outstanding success of recent mRNA vaccines against COVID-19 infection again highlighted the important role of RNA therapies in future medicine. In this review, we will first briefly provide the crucial investigations on RNA therapy, from the first pieces of discovery on RNA molecules to clinical applications of RNA therapeutics. We will then classify the mechanisms of RNA therapeutics from various classes in the treatment of diseases. To emphasize the huge potential of RNA therapies, we also provide the key RNA products that have been on clinical trials or already FDA-approved. With comprehensive knowledge on RNA biology, and the advances in analysis, technology and computer-aid science, RNA therapies can bring a promise to be more expanding to the market in the future.

RNA therapeutics for disorders of excretory system

The excretory system is responsible for removing wastes from the human body, which plays a crucial role in our lives. Current treatments for diseases related to this system have shown several limitations; therefore, there is a rising need for novel methods. In this circumstance, RNA-based therapeutics have rapidly emerged as new and promising candidates. In fact, to date, a handful of potential drugs have passed the development step and entered the clinical pipeline. Among them, one drug received FDA approval to enter the global market, which is Oxlumo (Lumasiran) for the treatment of primary hyperoxaluria type 1. For other excretory diseases, such as paroxysmal nocturnal hemoglobinuria, urothelial cancer or renal cancer, RNA-based candidates are also being tested under clinical trials. Currently, the most potential types of RNA therapeutics to treat disorders of the excretory system are those based on small interfering RNA (siRNA), antisense oligonucleotides (ASO) and messenger RNA (mRNA), Among them, siRNA therapeutics seem to be the most promising, including Oxlumo and two other developing drug candidates. This chapter will provide a general overview on the application of RNA therapeutics in disorders of the excretory system.

mRNA vaccine designs for optimal adjuvanticity and delivery

Adjuvanticity and delivery are crucial facets of mRNA vaccine design. In modern mRNA vaccines, adjuvant functions are integrated into mRNA vaccine nanoparticles, allowing the co-delivery of antigen mRNA and adjuvants in a unified, all-in-one formulation. In this formulation, many mRNA vaccines utilize the immunostimulating properties of mRNA and vaccine carrier components, including lipids and polymers, as adjuvants. However, careful design is necessary, as excessive adjuvanticity and activation of improper innate immune signalling can conversely hinder vaccination efficacy and trigger adverse effects. mRNA vaccines also require delivery systems to achieve antigen expression in antigen-presenting cells (APCs) within lymphoid organs. Some vaccines directly target APCs in the lymphoid organs, while others rely on APCs migration to the draining lymph nodes after taking up mRNA vaccines. This review explores the current mechanistic understanding of these processes and the ongoing efforts to improve vaccine safety and efficacy based on this understanding.

The mRNA vaccine, a swift warhead against a moving infectious disease target

INTRODUCTION

The rapid development of mRNA vaccines against SARS-CoV-2 has revolutionized vaccinology, offering hope for swift responses to emerging infectious diseases. Initially met with skepticism, mRNA vaccines have proven effective and safe, reducing vaccine hesitancy amid the evolving COVID-19 pandemic. The COVID-19 pandemic has demonstrated that the time required to modify mRNA vaccines to counter new mutant strains is significantly shorter than the time it takes for pathogens to mutate and generate new variants that can thrive in vaccinated populations. This highlights the notion that mRNA vaccine technology appears to be outpacing viruses in the ongoing evolutionary race.

AREAS COVERED

This review article offers valuable insights into several crucial aspects of mRNA vaccine development and deployment, including the fundamentals of mRNA vaccine design and synthesis, the utilization of delivery systems, considerations regarding vaccine safety, the longevity of the immune response, strategies for modifying the original mRNA vaccine to address emerging mutant strains, as well as addressing vaccine hesitancy and potential approaches to mitigate reluctance.

EXPERT OPINION

Challenges such as stability, storage, manufacturing complexities, production capacity, allergic reactions, long-term effects, accessibility, and misinformation must be addressed. Despite these hurdles, mRNA vaccine technology holds promise for revolutionizing future vaccination strategies.

Vaccine development: Current trends and technologies

Despite the effectiveness of vaccination in reducing or eradicating diseases caused by pathogens, there remain certain diseases and emerging infections for which developing effective vaccines is inherently challenging. Additionally, developing vaccines for individuals with compromised immune systems or underlying medical conditions presents significant difficulties. As well as traditional vaccine different methods such as inactivated or live attenuated vaccines, viral vector vaccines, and subunit vaccines, emerging non-viral vaccine technologies, including viral-like particle and nanoparticle vaccines, DNA/RNA vaccines, and rational vaccine design, offer new strategies to address the existing challenges in vaccine development. These advancements have also greatly enhanced our understanding of vaccine immunology, which will guide future vaccine development for a broad range of diseases, including rapidly emerging infectious diseases like COVID-19 and diseases that have historically proven resistant to vaccination. This review provides a comprehensive assessment of emerging non-viral vaccine production methods and their application in addressing the fundamental and current challenges in vaccine development.

Introduction to RNA Vaccines Post COVID-19

Available prophylactic vaccines help prevent many infectious diseases that burden humanity. Future vaccinology will likely extend these benefits by more effectively countering newly emerging pathogens, fighting currently intractable infections, or even generating novel treatment modalities for non-infectious diseases. Instead of applying protein antigen directly, RNA vaccines contain short-lived genetic information that guides the expression of protein antigen in the vaccinee, like infection with a recombinant viral vector. Upon decades of research, messenger RNA-lipid nanoparticle (mRNA-LNP) vaccines have proven clinical value in addressing the COVID-19 pandemic as they combine benefits of killed subunit vaccines and live-attenuated vectors, including flexible production, self-adjuvanting effects, and stimulation of humoral and cellular immunity. RNA vaccines remain subject to continued development raising high hopes for broader future application. Their mechanistic versatility promises to make them a key tool of vaccinology and immunotherapy going forward. Here, I briefly review key developments in RNA vaccines and outline the contents of this volume of Methods in Molecular Biology.