Identification of tumor antigens for mRNA vaccines and ferroptosis-related landscape in esophageal squamous cell carcinoma.

Background: Ferroptosis, an iron-dependent form of cell death that is characterized by lipid peroxidation, has been implicated in conferring resistance to cancer therapies and may contribute to the pathogenesis of esophageal squamous cell carcinoma (ESCC). Furthermore, messenger RNA (mRNA) vaccines have emerged as a promising modality in the treatment arsenal against diverse malignancies. The aim of the study was to investigate the role of ferroptosis subtypes in ESCC and the immune microenvironment, as well as to identify key genes that could serve as targets for mRNA vaccine development. Methods: Gene expression profiles and clinical data from 79 and 358 ESCC patients were collected from The Cancer Genome Atlas and Gene Expression Omnibus databases. Subsequently, we identified tumor mutational burden (TMB), immune microenvironment scores, and immune checkpoint and immune cell dysfunction genes for each ferroptosis subtype. Furthermore, we utilized weighted gene co-expression network analysis (WGCNA) to describe the immune landscape of ESCC and identify key genes for mRNA vaccine development. Results: Our analysis revealed that MMD, MTDH, and TRFC were overexpressed ferroptosis genes in ESCC. In addition, ESCC was categorized into two ferroptosis subtypes, namely FS1 and FS2. Notably, FS2 exhibited a poorer prognosis, higher TMB, and increased immune cell infiltration when compared to FS1. The ferroptosis landscape analysis further revealed the presence of three distinct states. WGCNA analysis identified different modules of interest emerging as an independent prognostic factor and enriched with hub genes that could serve as targets for mRNA vaccine development. Conclusions: The ferroptosis subtypes demonstrated significant associations with both prognosis and the immune microenvironment in ESCC. Additionally, the module of interest identified through immune landscape analysis represented an independent prognostic factor, with its contained genome offering promising targets for mRNA vaccine development.

Efficacy, Effectiveness, and Safety of COVID-19 Vaccine Compared to Placebo in Preventing COVID-19 Infection among 12-17 Years Old: A Systematic Review.

Objectives: The World Health Organization recently revised their recommendations and considered healthy children and adolescents as low priority group for COVID-19 vaccine. This review comprehensively assessed existing clinical evidence on COVID-19 vaccine in 12-17 years old. Methods: Included in this review were any type of study that investigated the efficacy, immunogenicity, safety, and effectiveness of COVID-19 vaccine on protection against SARS-COV-2 infection in 12-17 years old. Various electronic databases were searched up to March 15, 2023. Studies were screened, data extracted, risk of bias appraised, and certainty of evidence was judged using GRADE. Review Manager 5.4 was used to estimate pooled effects. Difference between the two groups was described as mean difference for continuous variables and as relative risk or odds ratio for categorical variables. Results: There were six randomized controlled trials and 16 effectiveness studies (8 cohorts and 8 case control). Low certainty evidence showed that BNT162b2 (Pfizer) was effective, immunogenic, and safe in healthy adolescents. There were 15 effectiveness studies on BNT162b2 (Pfizer) in healthy adolescent and one on immunocompromised patients. It was protective against infection with any of the variants, with higher protection against Delta than Omicron. BNT162b2 is protective against hospitalization and emergency and urgent care (high certainty); and critical care and MIS-C (low). Very low certainty evidence noted that BNT 162b2 was also immunogenic in 12-21 years old with rheumatic diseases while on immunomodulatory treatment but with possible increased exacerbation of illness. Low certainty evidence demonstrated that mRNA-1273 (Moderna) was effective, immunogenic, and safe. Low to very low certainty evidence were noted on the safety and immunogenicity of two vector base vaccines (ChAdOx1-19 and Ad5 vector COVID vaccine) and two inactivated vaccines (CoronaVac and BBIBP CorV). CONCLUSION: There is presently low certainty evidence on the use of RNA vaccines in 12-17 years old. The recommendation on its use is weak. There is presently insufficient evidence for the use of inactivated and vector-based COVID-19 vaccines. Different countries should consider whether to vaccinate healthy adolescent without comprising the other recommended immunization and health priorities that are crucial for this age group. Other factors including cost-effectiveness of vaccination and disease burden should be accounted.

Design of novel chiral self-assembling peptides to explore the efficiency and mechanism of mRNA-FIPV vaccine delivery vehicles.

The enhancement of conventional liposome and lipid nanoparticle (LNP) methodologies in the formulation and deployment of messenger RNA (mRNA) vaccines necessitates further refinement to augment both their effectiveness and biosafety profiles. Additionally, researching these innovative delivery carrier materials represents both a prominent focus and a significant challenge in the current scientific landscape. Here we designed new chiral self-assembling peptides as the delivery carrier for RNA vaccines to study the underlying mechanisms in the feline infectious peritonitis virus (FIPV) model system. Firstly, we successfully transcribed mature enhanced green fluorescent protein (EGFP) mRNA and feline infectious peritonitis virus nucleocapsid (FIPV N) mRNA in vitro from optimized vectors. Subsequently, we developed chiral self-assembling peptide-1 (CSP-1) and chiral self-assembling peptide-2 (CSP-2) peptides, taking into account the physical and chemical characteristics of nucleic acid molecules as well as the principles of self-assembling peptides, with the aim of improving the delivery efficiency of mRNA molecule complexes. We determined the optimal coating ratio between CSP and mRNA by electrophoretic mobility shift assay. We found that the peptides and mRNA complexes can protect the mRNA from RNase A enzyme and efficiently deliver mRNA into cells for target antigen proteins expression. Animal experiments confirmed that CSP-1/mRNA complex can effectively trigger immune response mechanisms involving IFN-γ and T cell activation. It can also stimulate CD4+ and CD8+ T cell proliferation and induce serum antibody titers up to 10,000 times higher. And no pathological changes were observed by immunohistochemistry in liver, spleen, and kidney, indicating that CSP-1 may be a safe and promising delivery system for mRNA vaccines. Methodologically, this research represents a novel endeavor in the utilization of chiral self-assembling peptides within the realm of mRNA vaccines. This approach not only introduces fresh prospects for employing such nanomaterials in various mRNA vaccines but also expands the potential for developing small molecules, proteins, and antibodies. Furthermore, it paves the way for new clinical applications of existing pharmaceuticals.

Advancements in clinical RNA therapeutics: Present developments and prospective outlooks.

RNA molecules have emerged as promising clinical therapeutics due to their ability to target "undruggable" proteins or molecules with high precision and minimal side effects. Nevertheless, the primary challenge in RNA therapeutics lies in rapid degradation and clearance from systemic circulation, the inability to traverse cell membranes, and the efficient intracellular delivery of bioactive RNA molecules. In this review, we explore the implications of RNAs in diseases and provide a chronological overview of the development of RNA therapeutics. Additionally, we summarize the technological advances in RNA-screening design, encompassing various RNA databases and design platforms. The paper then presents an update on FDA-approved RNA therapeutics and those currently undergoing clinical trials for various diseases, with a specific emphasis on RNA medicine and RNA vaccines.

Anti-SARS-CoV-2 Spike Antibody Response to the Fourth Dose of BNT162b2 mRNA COVID-19 Vaccine and Associated Factors in Japanese Hemodialysis Patients.

Background: We assessed the anti-SARS-CoV-2 spike antibody response to four doses of BNT162b2 mRNA COVID-19 vaccine in Japanese hemodialysis patients and determined factors associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose. Methods: Fifty-one patients were enrolled in this single-center, prospective, longitudinal study. Change in anti-SARS-CoV-2 spike antibody titers between after the second and fourth doses were evaluated. Multiple linear regression analysis was used to identify factors associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose. Results: The anti-SARS-CoV-2 spike antibody titer was higher 4 weeks after the fourth dose compared with 4 weeks after the third dose (30,000 [interquartile range (IQR), 14,000-56,000] vs 18,000 [IQR, 11,000-32,500] AU/mL, p<0.001) and 4 weeks after the second dose (vs 2896 [IQR, 1110-4358] AU/mL, p<0.001). Hypoxia-inducible factor prolyl hydroxylase inhibitor use (standard coefficient [ß]=0.217, p=0.011), and the log-anti-SARS-CoV-2 spike antibody titer 1 week before the fourth dose (ß=0.810, p<0.001) were correlated with the log-anti-SARS-CoV-2 spike antibody titer 4 weeks after the fourth dose, whereas only the log-anti-SARS-CoV-2 spike antibody titer 1 week before the fourth dose (ß=0.677, p<0.001) was correlated with the log-anti-SARS-CoV-2 spike antibody titer 12 weeks after the fourth dose. Conclusion: Hypoxia-inducible factor prolyl hydroxylase inhibitor use and the anti-SARS-CoV-2 spike antibody titer before the fourth dose were associated with the anti-SARS-CoV-2 spike antibody titer after the fourth dose in Japanese hemodialysis patients.

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.

Cross-neutralizing antibody against emerging Omicron subvariants of SARS-CoV-2 in infection-naïve individuals with homologous BNT162b2 or BNT162b2(WT + BA.4/5) bivalent booster vaccination.

Since the emergence of SARS-CoV-2, different variants and subvariants successively emerged to dominate global virus circulation as a result of immune evasion, replication fitness or both. COVID-19 vaccines continue to be updated in response to the emergence of antigenically divergent viruses, the first being the bivalent RNA vaccines that encodes for both the Wuhan-like and Omicron BA.5 subvariant spike proteins. Repeated infections and vaccine breakthrough infections have led to complex immune landscapes in populations making it increasingly difficult to assess the intrinsic neutralizing antibody responses elicited by the vaccines. Hong Kong's intensive COVID-19 containment policy through 2020-2021 permitted us to identify sera from a small number of infection-naïve individuals who received 3 doses of the RNA BNT162b2 vaccine encoding the Wuhan-like spike (WT) and were boosted with a fourth dose of the WT vaccine or the bivalent WT and BA.4/5 spike (WT + BA.4/5). While neutralizing antibody to wild-type virus was comparable in both vaccine groups, BNT162b2 (WT + BA.4/BA.5) bivalent vaccine elicited significantly higher plaque neutralizing antibodies to Omicron subvariants BA.5, XBB.1.5, XBB.1.16, XBB.1.9.1, XBB.2.3.2, EG.5.1, HK.3, BA.2.86 and JN.1, compared to BNT162b2 monovalent vaccine. The single amino acid substitution that differentiates the spike of JN.1 from BA.2.86 resulted in a profound antigenic change.

Lymphatic Endothelial Cells Produce Chemokines in Response to the Lipid Nanoparticles Used in RNA Vaccines.

RNA vaccines based on Lipid nanoparticles (LNP) were put into practical use within only one year after the global outbreak of the coronavirus disease 2019 (COVID-19). This success of RNA vaccine highlights the utility of an mRNA delivery system as a vaccination strategy. Potent immunostimulatory activity of LNPs (i.e., inflammation occurring at the injection site and the production of inflammatory cytokines) have recently been reported. However, we have only limited knowledge concerning which cells are responsible for responding to the LNPs. We report herein on in vitro chemokine production from non-immune cells in response to exposure to LNPs. In this study, SM-102, an ionizable lipid that is used in the approved RNA vaccine for the clinical usage of COVID-19 mRNA vaccine, was used. Immortalized mouse lymphatic endothelial cells (mLECs) or professional antigen presenting cells (APCs) such as RAW 264.7 monocyte/macrophage cells were incubated with LNPs that contained no mRNA. As a result, chemokines involved in the recruitment of monocytes/neutrophils were produced only by the mLECs following the LNP treatment. These findings indicate that LEC appear to serve as the cell that sends out initial signals to response LNPs.

RNA-Based Therapeutics: Past, Present and Future Prospects, Challenges in Cancer Treatment.

It is becoming more and harder in today's climate to disregard the impact of cancer on social health. Even though a significant amount of money is spent annually on cancer research, it still ranks as the second leading cause of death worldwide. Additionally, only about half of the patients suffering from complex forms of cancer survive a year after receiving traditional cancer therapies. A method for silencing genes is called RNA interference (RNAi). Such a method is very effective in focusing on genes linked to cancer. Most gene products implicated in cancer have recently been used as RNA interference (RNAi) therapeutic targets. According to the findings from this research, RNAi application is necessary for today's cancer treatment to target functioning carcinogenic molecules and tumor resistance to chemotherapy and radiation. Proapoptotic and antiproliferative activity has been reported from previous research studies on cell culture systems, animal models, and clinical trials through the knockdown of gene products from RNAi technology. Numerous novel RNAi-based medications are now in the clinical trial stages thanks to the discovery of the RNAi mechanism and advancements in the area. In the future, genomic-based personalized medicines can be developed through this RNAi therapy. Hopefully, cancer sufferers will find this sort of therapy to be one of the most effective ones. Various kinds of RNA-based treatments, such as aptamers, small interfering RNAs, microRNAs, antisense oligonucleotides, and messenger RNA, are covered in broad terms in this study. We also present an overview of the RNA-based therapies that have received regulatory approval in the past or are now undergoing clinical studies.

Achievements of COVID-19 vaccination programs: Taiwanese perspective.

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global health crisis. The specific characteristics of aerosol transmission in the latent period and the contagiousness of SARS-CoV-2 lead to rapid spread of infection in the community. Vaccination is the most effective method for preventing infection and severe outcomes. As of December 1, 2022, 88% of the Taiwanese population had received at least two doses of COVID-19 vaccines. Heterologous vaccination with ChAdOx1-mRNA-based or ChAdOx1-protein-based vaccines has been found to elicit higher immunogenicity than homologous vaccination with ChAdOx1-ChAdOx1 vaccines. A longitudinal cohort study revealed that 8-12-week intervals between the two heterologous vaccine doses of the primary series led to good immunogenicity and that the vaccines were safe. A third booster dose of mRNA vaccine is being encouraged to evoke effective immune responses against variants of concern. A novel domestic recombinant protein subunit vaccine (MVC-COV1901) was manufactured and authorized for emergency use in Taiwan. It has shown a good safety profile, with promising neutralizing antibody titers against SARS-CoV-2. Given the global pandemic due to emerging novel variants of SARS-CoV-2, booster COVID-19 vaccines and appropriate intervals between booster doses need to be investigated.

Immunogenicity and safety of heterologous booster with protein-based COVID-19 vaccine (NVX-CoV2373) in healthy adults: A comparative analysis with mRNA vaccines.

BACKGROUND: Information on the protein-based severe acute respiratory syndrome (SARS-CoV-2) vaccine-NVX-CoV2373 (Novavax), as a heterologous booster remains limited. We investigated the immunogenicity and adverse events of NVX-CoV2373 as a second booster and compared them with those of mRNA vaccines in healthy adults. METHODS: Healthcare workers who had received an mRNA vaccine (mRNA-1273 or BNT-162b2) as the first booster (third dose) 12 weeks prior were recruited. Participants voluntarily received either NVX-CoV2373 or an mRNA vaccine as a second booster. Participants with a history of SARS-CoV-2 infection were excluded. The primary outcomes included serum anti-SARS-CoV-2 spike protein (SP) and neutralizing antibody titers against B.1.1.7 (Alpha), B.1.1.529 (Omicron) BA2, and BA5 variants on the 28th day after the boost. Secondary outcomes included new SARS-CoV-2 infections and adverse events reported during the study period. RESULTS: A total of 160 participants were enrolled in this study. Compared with the mRNA vaccination group (n = 59), the NVX-CoV2373 vaccination group (n = 101) had significantly lower anti-SARS-CoV-2 SP antibody titers and neutralizing antibody titers against all variants tested after the boost. During the study period, higher rates of new SARS-CoV-2 infections and a lower incidence of adverse events were observed in the NVX-CoV2373 vaccination group. No significant differences in cellular immune responses were observed between the two groups. CONCLUSION: Compared to a homologous mRNA booster vaccination, heterologous boosters with NVX-CoV2373 showed lower antibody responses, a higher incidence of new SARS-CoV-2 infections, and fewer adverse events.

A singlicate immunogenicity method to detect anti-polyethylene glycol antibodies: pre- and post-dose of PEGylated therapies.

Aim: Preexisting anti-polyethylene glycol (PEG) antibodies (APAs) may affect the efficacy and safety of PEGylated compounds. Omontys® and Krystexxa® withdrawal and SARS-CoV-2 RNA vaccine anaphylaxis have all been linked to APAs. This project aimed to develop and validate a method to detect total antibodies against PEG, pre- and post-dose. Materials & methods: The repetitive, linear PEG structure prevented the use of a bridging homogenous format, hence the requirement to use a solid-phase extraction and acid dissociation assay coupled with the Meso Scale Discovery® platform. Results & conclusion: Using singlicate analysis, the method was validated to successfully detect APA pre- and post-dose, with a crucial aspect of the method being the preparation of an appropriate negative control.

A Study to Describe the Pattern of Cutaneous Adverse Effects of COVID-19 Vaccines (Covishield and Covaxin).

Background: Vigorous administration of COVID-19 vaccines to tackle the ongoing pandemic has led to increasing research on adverse effects including both systemic and cutaneous. Objective: A prospective observational study to delineate the cutaneous adverse effects of two vaccines, namely Covishield and Covaxin, administered in two doses in northern India. Materials and Methods: The study was conducted in a tertiary hospital in northern India wherein patients were asked to report voluntarily any cutaneous adverse effects after COVID-19 vaccination to the dermatology department. The data were collected using excel sheets and later analyzed taking into consideration the age, vaccine types, and duration of onset of adverse effects. Results: Of the 19,672 vaccination jabs, 296 (1.5%) developed cutaneous adverse effects of which the incidence was higher in Covishield vaccine group compared to Covaxin vaccine group. The incidence of side effects was more with the first dose of either vaccine compared to the second dose. All the side effects were benign and were managed symptomatically or were self-limiting. Limitations: The number of vaccine recipients was limited and there was a considerable overlap of adverse effects with both vaccines. Voluntary reporting of cases is not an accurate representation of the scale of patients with adverse effects. Conclusion: Rampant administration of vaccines along with widespread advertisement of vaccine-induced side effects via social media has created apprehension in the general population. This warrants studies improving awareness about the most vital preventive measure available to halt and eventually end the COVID-19 pandemic.

Low-sugar universal mRNA vaccine against coronavirus variants with deletion of glycosites in the S2 or stem of SARS-CoV-2 spike messenger RNA (mRNA).

Since the outbreak of Severe Acute Respiratory Syndrome Virus-2 (SARS-CoV-2) in 2019, more than 15 million spike protein sequences have been identified, raising a new challenge for the development of a broadly protective vaccine against the various emerging variants. We found that the virus, like most other human viruses, depends on host-made glycans to shield the conserved epitopes on spike protein from immune response and demonstrated that deletion of the glycan shields exposed highly conserved epitopes and elicited broadly protective immune responses. In this study, we identified 17 conserved epitopes from 14 million spike protein sequences and 11 of the conserved epitopes are in the S2 domain, including the six most conserved epitopes in the stem region. We also demonstrated that deletion of the glycosites in the spike messenger RNA (mRNA) S2 domain or the stem region exposed the highly conserved epitopes and elicited broadly protective immune responses, particularly CD-8+ T cell response against various SARS-CoV-2 variants, and other human coronaviruses including MERS, SARS viruses, and those causing common cold.

In Vitro Transcribed RNA-Based Platform Vaccines: Past, Present, and Future.

mRNA was discovered in 1961, but it was not used as a vaccine until after three decades. Recently, the development of mRNA vaccine technology gained great impetus from the pursuit of vaccines against COVID-19. To improve the properties of RNA vaccines, and primarily their circulation time, self-amplifying mRNA and trans-amplifying mRNA were developed. A separate branch of mRNA technology is circular RNA vaccines, which were developed with the discovery of the possibility of translation on their protein matrix. Circular RNA has several advantages over mRNA vaccines and is considered a fairly promising platform, as is trans-amplifying mRNA. This review presents an overview of the mRNA platform and a critical discussion of the more modern self-amplifying mRNA, trans-amplifying mRNA, and circular RNA platforms created on its basis. Finally, the main features, advantages, and disadvantages of each of the presented mRNA platforms are discussed. This discussion will facilitate the decision-making process in selecting the most appropriate platform for creating RNA vaccines against cancer or viral diseases.

Reducing cell intrinsic immunity to mRNA vaccine alters adaptive immune responses in mice.

The response to mRNA vaccines needs to be sufficient for immune cell activation and recruitment, but moderate enough to ensure efficacious antigen expression. The choice of the cap structure and use of N1-methylpseudouridine (m1Ψ) instead of uridine, which have been shown to reduce RNA sensing by the cellular innate immune system, has led to improved efficacy of mRNA vaccine platforms. Understanding how RNA modifications influence the cell intrinsic immune response may help in the development of more effective mRNA vaccines. In the current study, we compared mRNA vaccines in mice against influenza virus using three different mRNA formats: uridine-containing mRNA (D1-uRNA), m1Ψ-modified mRNA (D1-modRNA), and D1-modRNA with a cap1 structure (cC1-modRNA). D1-uRNA vaccine induced a significantly different gene expression profile to the modified mRNA vaccines, with an up-regulation of Stat1 and RnaseL, and increased systemic inflammation. This result correlated with significantly reduced antigen-specific antibody responses and reduced protection against influenza virus infection compared with D1-modRNA and cC1-modRNA. Incorporation of m1Ψ alone without cap1 improved antibodies, but both modifications were required for the optimum response. Therefore, the incorporation of m1Ψ and cap1 alters protective immunity from mRNA vaccines by altering the innate immune response to the vaccine material.

Quadrivalent neuraminidase RNA particle vaccine protects pigs against homologous and heterologous strains of swine influenza virus infection.

Influenza A virus in swine (IAV-S) continues to cause significant negative impact to both sows and growing pigs. The viral hemagglutinin (HA) and neuraminidase (NA) genes continue to evolve with HA diversifying at a faster rate than NA. Depending on country, whole inactivated virus (WIV) commercial and autogenous vaccines, as well as veterinary prescription vaccines targeting HA, are currently available. The use of these vaccines is focused on reducing virus and clinical signs in sows and to provide HA-specific maternally derived antibodies (MDA) to their suckling pigs. The deficiency in this strategy is that HA-MDA does not persist long enough to protect pigs through their growing phase from infection, and HA-MDA can interfere with effective pig immunization. This study evaluated the immunogenicity and efficacy of an adjuvanted, quadrivalent RNA Particle vaccine (Sequivity NA), currently licensed as Sequivity® IAV-S NA. This vaccine was formulated based on four NA antigens representing the major NA clades of IAV subtypes H1N1, H1N2 and H3N2 circulating in swine herds in the United States. In a series of trials, pigs were vaccinated twice, at three days and three weeks of age (WOA), followed by challenge with either homologous or heterologous IAV strains at 8 or 15 WOA. The Sequivity NA vaccine induced robust serum NA inhibition (NI) antibody and protected against IAV-S strains with homologous and heterologous NA to that of the vaccine. The magnitude and duration of nasal shedding was reduced in vaccinated-pigs challenged with either homologous or heterologous virus within the same NA clade. This NA-based RNA Particle vaccine avoids the known impact of HA-MDA on pig vaccination and provides a new tool to successfully reduce IAV-induced disease in the pig population.

RNA Nanomedicine: Delivery Strategies and Applications.

Delivery of RNA using nanomaterials has emerged as a new modality to expand therapeutic applications in biomedical research. However, the delivery of RNA presents unique challenges due to its susceptibility to degradation and the requirement for efficient intracellular delivery. The integration of nanotechnologies with RNA delivery has addressed many of these challenges. In this review, we discuss different strategies employed in the design and development of nanomaterials for RNA delivery. We also highlight recent advances in the pharmaceutical applications of RNA delivered via nanomaterials. Various nanomaterials, such as lipids, polymers, peptides, nucleic acids, and inorganic nanomaterials, have been utilized for delivering functional RNAs, including messenger RNA (mRNA), small interfering RNA, single guide RNA, and microRNA. Furthermore, the utilization of nanomaterials has expanded the applications of functional RNA as active pharmaceutical ingredients. For instance, the delivery of antigen-encoding mRNA using nanomaterials enables the transient expression of vaccine antigens, leading to immunogenicity and prevention against infectious diseases. Additionally, nanomaterial-mediated RNA delivery has been investigated for engineering cells to express exogenous functional proteins. Nanomaterials have also been employed for co-delivering single guide RNA and mRNA to facilitate gene editing of genetic diseases. Apart from the progress made in RNA medicine, we discuss the current challenges and future directions in this field.

An Ionizable Lipid Material with a Vitamin E Scaffold as an mRNA Vaccine Platform for Efficient Cytotoxic T Cell Responses.

RNA vaccines based on lipid nanoparticles (LNPs) with in vitro transcribed mRNA (IVT-mRNA) encapsulated are now a currently successful but still evolving modality of vaccines. One of the advantages of RNA vaccines is their ability to induce CD8+ T-cell-mediated cellular immunity that is indispensable for excluding pathogen-infected cells or cancer cells from the body. In this study, we report on the development of LNPs with an enhanced capability for inducing cellular immunity by using an ionizable lipid with a vitamin E scaffold. An RNA vaccine that contained this ionizable lipid and an IVT-mRNA encoding a model antigen ovalbumin (OVA) induced OVA-specific cytotoxic T cell responses and showed an antitumor effect against an E.G7-OVA tumor model. Vaccination with the LNPs conferred protection against lethal infection by Toxoplasma gondii using its antigen TgPF. The vitamin E scaffold-dependent type I interferon response was important for effector CD8+ T cell differentiation induced by the mRNA-LNPs. Our findings also revealed that conventional dendritic cells (cDCs) were essential for achieving CD8+ T cell responses induced by the mRNA-LNPs, while the XCR1-positive subset of cDCs, cDC1 specialized for antigen cross-presentation, was not required. Consistently, the mRNA-LNPs were found to selectively transfect another subset of cDCs, cDC2 that had migrated from the skin to lymph nodes, where they could make vaccine-antigen-dependent contacts with CD8+ T cells. The findings indicate that the activation of innate immune signaling by the adjuvant activity of the vitamin E scaffold and the expression of antigens in cDC2 are important for subsequent antigen presentation and the establishment of antigen-specific immune responses.

A nasal vaccine with inactivated whole-virion elicits protective mucosal immunity against SARS-CoV-2 in mice.

Introduction: Vaccinations are ideal for reducing the severity of clinical manifestations and secondary complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2); however, SARS-CoV-2 continues to cause morbidity and mortality worldwide. In contrast to parenteral vaccines such as messenger RNA vaccines, nasal vaccines are expected to be more effective in preventing viral infections in the upper respiratory tract, the primary locus for viral infection and transmission. In this study, we examined the prospects of an inactivated whole-virion (WV) vaccine administered intranasally against SARS-CoV-2. Methods: Mice were immunized subcutaneously (subcutaneous vaccine) or intranasally (nasal vaccine) with the inactivated WV of SARS-CoV-2 as the antigen. Results: The spike protein (S)-specific IgA level was found to be higher upon nasal vaccination than after subcutaneous vaccination. The level of S-specific IgG in the serum was also increased by the nasal vaccine, although it was lower than that induced by the subcutaneous vaccine. The nasal vaccine exhibited a stronger defense against viral invasion in the upper respiratory tract than the subcutaneous vaccine and unimmunized control; however, both subcutaneous and nasal vaccines provided protection in the lower respiratory tract. Furthermore, we found that intranasally administered inactivated WV elicited robust production of S-specific IgA in the nasal mucosa and IgG in the blood of mice previously vaccinated with messenger RNA encoding the S protein. Discussion: Overall, these results suggest that a nasal vaccine containing inactivated WV can be a highly effective means of protection against SARS-CoV-2 infection.