Incorporation of a Toll-like receptor 2/6 agonist potentiates mRNA vaccines against cancer and infectious diseases

Development of multi-epitope mRNA vaccine against Clostridioides difficile using reverse vaccinology and immunoinformatics approaches

Clostridioides difficile (C. difficile), as the major pathogen of diarrhea in healthcare settings, has become increasingly prevalent within community populations, resulting in significant morbidity and mortality. However, the therapeutic options for Clostridioides difficile infection (CDI) remain limited, and as of now, no authorized vaccine is available to combat this disease. Therefore, the development of a novel vaccine against C. difficile is of paramount importance. In our study, the complete proteome sequences of 118 strains of C. difficile were downloaded and analyzed. We found four antigenic proteins that were highly conserved and can be used for epitope identification. We designed two vaccines, WLcd1 and WLcd2, that contain the ideal T-cell and B-cell epitopes, adjuvants, and the pan HLA DR-binding epitope (PADRE) sequences. The biophysical and chemical assessments of these vaccine candidates indicated that they were suitable for immunogenic applications. Molecular docking analyses revealed that WLcd1 bonded with higher affinity to Toll-like receptors (TLRs) than WLcd2. Furthermore, molecular dynamics (MD) simulations, performed using Gmx_MMPBSA v1.56, confirmed the binding stability of WLcd1 with TLR2 and TLR4. The preliminary findings suggested that this multi-epitope vaccine could be a promising candidate for protection against CDI; however, experimental studies are necessary to confirm these predictions.

mRNA vaccine development and applications: A special focus on tumors (Review)

Cancer is characterized by unlimited proliferation and metastasis, and traditional therapeutic strategies usually result in the acquisition of drug resistance, thus highlighting the need for more personalized treatment. mRNA vaccines transfer the gene sequences of exogenous target antigens into human cells through transcription and translation to stimulate the body to produce specific immune responses against the encoded proteins, so as to enable the body to obtain immune protection against said antigens; this approach may be adopted for personalized cancer therapy. Since the recent coronavirus pandemic, the development of mRNA vaccines has seen substantial progress and widespread adoption. In the present review, the development of mRNA vaccines, their mechanisms of action, factors influencing their function and the current clinical applications of the vaccine are discussed. A focus is placed on the application of mRNA vaccines in cancer, with the aim of highlighting unique advances and the remaining challenges of this novel and promising therapeutic approach.

Generation of an inflammatory niche in an injectable hydrogel depot through recruitment of key immune cells improves efficacy of mRNA vaccines

Messenger RNA (mRNA) delivered in lipid nanoparticles (LNPs) rose to the forefront of vaccine candidates during the COVID-19 pandemic due in part to scalability, adaptability, and potency. Yet there remain critical areas for improvements of these vaccines in durability and breadth of humoral responses. In this work, we explore a modular strategy to target mRNA/LNPs to antigen presenting cells with an injectable polymer-nanoparticle (PNP) hydrogel depot technology which recruits key immune cells and forms an immunological niche in vivo. We characterize this niche on a single cell level and find it is highly tunable through incorporation of adjuvants like MPLAs and 3M-052. Delivering commercially available SARS-CoV-2 mRNA vaccines in PNP hydrogels improves the durability and quality of germinal center reactions, and the magnitude, breadth, and durability of humoral responses. The tunable immune niche formed within PNP hydrogels effectively skews immune responses based on encapsulated adjuvants, creating opportunities to precisely modulate mRNA/LNP vaccines for various indications from infectious diseases to cancers.

Peptide-TLR7/8a-Coordinated DNA Vaccines Elicit Enhanced Immune Responses against Infectious Diseases

DNA vaccines represent an innovative approach for the immunization of diverse diseases. However, their clinical trial outcomes are constrained by suboptimal transfection efficiency and immunogenicity. In this work, we present a universal methodology involving the codelivery of Toll-like receptor 7/8 agonists (TLR7/8a) and antigen gene using TLR7/8a-conjugated peptide-coated poly(β-amino ester) (PBAE) nanoparticles (NPs) to augment delivery efficiency and immune response. Peptide-TLR7/8a-coated PBAE NPs exhibit advantageous biophysical attributes, encompassing diminutive particle dimensions, nearly neutral ζ potential, and stability in the physiological environment. This synergistic approach not only ameliorates the stability of plasmid DNA (pDNA) and gene delivery efficacy but also facilitates subsequent antigen production. Furthermore, under optimal formulation conditions, the TLR7/8a-conjugated peptide coated PBAE NPs exhibit a potent capacity to induce robust immune responses. Collectively, this nanoparticulate gene delivery system demonstrates heightened transfection efficacy, stability, biodegradability, immunostimulatory effect, and low toxicity, making it a promising platform for the clinical advancement of DNA vaccines.

Research Advances of Lipid Nanoparticles in the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a common type of gastrointestinal tract (GIT) cancer and poses an enormous threat to human health. Current strategies for metastatic colorectal cancer (mCRC) therapy primarily focus on chemotherapy, targeted therapy, immunotherapy, and radiotherapy; however, their adverse reactions and drug resistance limit their clinical application. Advances in nanotechnology have rendered lipid nanoparticles (LNPs) a promising nanomaterial-based drug delivery system for CRC therapy. LNPs can adapt to the biological characteristics of CRC by modifying their formulation, enabling the selective delivery of drugs to cancer tissues. They overcome the limitations of traditional therapies, such as poor water solubility, nonspecific biodistribution, and limited bioavailability. Herein, we review the composition and targeting strategies of LNPs for CRC therapy. Subsequently, the applications of these nanoparticles in CRC treatment including drug delivery, thermal therapy, and nucleic acid-based gene therapy are summarized with examples provided. The last section provides a glimpse into the advantages, current limitations, and prospects of LNPs in the treatment of CRC.

Optimized lipid nanoparticles (LNPs) for organ-selective nucleic acids delivery in vivo

Nucleic acid therapeutics offer tremendous promise for addressing a wide range of common public health conditions. However, the in vivo nucleic acids delivery faces significant biological challenges. Lipid nanoparticles (LNPs) possess several advantages, such as simple preparation, high stability, efficient cellular uptake, endosome escape capabilities, etc., making them suitable for delivery vectors. However, the extensive hepatic accumulation of LNPs poses a challenge for successful development of LNPs-based nucleic acid therapeutics for extrahepatic diseases. To overcome this hurdle, researchers have been focusing on modifying the surface properties of LNPs to achieve precise delivery. The review aims to provide current insights into strategies for LNPs-based organ-selective nucleic acid delivery. In addition, it delves into the general design principles, targeting mechanisms, and clinical development of organ-selective LNPs. In conclusion, this review provides a comprehensive overview to provide guidance and valuable insights for further research and development of organ-selective nucleic acid delivery systems.

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.

Differential expression and prognostic value of TLR4 in kidney renal clear cell carcinoma

Human Toll-like receptor (TLR) family plays a crucial role in immunity and cancer progression. However, the specific role of human Toll-like receptor 4 (TLR4) in kidney renal clear cell carcinoma (KIRC) remains obscure. Thus, we used single-cell RNA sequencing (RNA-seq) and bulk RNA-seq data combined with in vitro studies to evaluate the expression and prognostic value of TLR4 in KIRC. In our study, we observed that TLR4 was over expressed in KIRC tissues compared to normal renal tissues. And the expression of TLR4 was higher in macrophages/monocytes than other cell types. Besides, there is a close association between TLR4 expression and immune cell infiltration (Neutrophils, Macrophages, T cells and B cells) in KIRC. Immunohistochemical staining also showed that TLR4 was overexpressed in inflammatory infiltration renal tissue compared with normal tissue. Meanwhile, high expression of TLR4 exhibited correlations with improved survival, lower tumor grade and stage. Interestingly, the protective significance of TLR4 only showed in female patients (HR = 0.37, P < 0.01), other than male patients (HR = 0.71, P = 0.08) with KIRC. Consistently, KIRC samples with lymph node metastasis showed lower expression of TLR4. Knockdown of TLR4 in 786-O cell line increased cell proliferation and clonogenic capacity. In summary, this study found TLR4 could inhibit the progression of kidney cancer and was associated with improved survival in KIRC. The overexpression of TLR4 in macrophages and the close association between TLR4 and immune cell infiltration also underline the critical role of TLR4 in building the immune microenvironment for kidney cancer. These results may offer insights into the mechanism and immune microenvironment of kidney cancer.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

Decoding Toll-like receptors: Recent insights and perspectives in innate immunity

Toll-like receptors (TLRs) are an evolutionarily conserved family in the innate immune system and are the first line of host defense against microbial pathogens by recognizing pathogen-associated molecular patterns (PAMPs). TLRs, categorized into cell surface and endosomal subfamilies, recognize diverse PAMPs, and structural elucidation of TLRs and PAMP complexes has revealed their intricate mechanisms. TLRs activate common and specific signaling pathways to shape immune responses. Recent studies have shown the importance of post-transcriptional regulation in TLR-mediated inflammatory responses. Despite their protective functions, aberrant responses of TLRs contribute to inflammatory and autoimmune disorders. Understanding the delicate balance between TLR activation and regulatory mechanisms is crucial for deciphering their dual role in immune defense and disease pathogenesis. This review provides an overview of recent insights into the history of TLR discovery, elucidation of TLR ligands and signaling pathways, and their relevance to various diseases.

Harnessing innate immune pathways for therapeutic advancement in cancer

The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.

In silico development of a novel anti-mutation, multi-epitope mRNA vaccine against MPXV variants of emerging lineage and sub-lineages by using immunoinformatics approaches

Over the past year, an unexpected surge in human monkeypox (hMPX) cases has been observed. This outbreak differs from previous ones, displaying distinct epidemiological characteristics and transmission patterns, believed to be influenced by a newly emerging monkeypox virus (MPXV) lineage. Notably, this emerging MPXV lineage has exhibited several non-synonymous mutations, some of which are linked to immunomodulatory activities and antigenic characteristics that aid in host detection. However, specific treatments or vaccines for human monkeypox are currently lacking. Hence, we aim to develop a multi-epitope mRNA vaccine by using immunoinformatics approaches against the MPXV, particularly its emerging variants. Six proteins (A29L, A35R, B6R, M1R, H3L, and E8L) were chosen for epitope and mutation site identification. Seventeen top-performing epitopes and eight epitopes containing mutation sites were selected and combined with adjuvants, the PADRE sequence, and linkers for vaccine development. The molecular and physical properties of the designed vaccine (WLmpx) were favorable. Immunological characteristics of WLmpx were assessed through molecular docking, molecular dynamics (MD) simulations, and immune simulations. Finally, the vaccine sequence was utilized to formulate an mRNA-based vaccine. The informatics-based predicted results indicated that the designed vaccine exhibits significant potential in eliciting high-level humoral and cellular immune responses, but further validation through in vivo and vitro studies is warranted.Communicated by Ramaswamy H. Sarma.

Chiral Nanomaterials for Cancer Vaccines

Chirality is a fundamental characteristic of living organisms and is commonly observed at the biomolecule, cellular, and tissue levels. Chiral nanomaterials play an irreplaceable role in nanomedicine and nanobiology because of their unique enantioselectivity with biological components. Here, research progress relating to chiral nanomaterials in the field of vaccines is reviewed, including antigen presenting systems, immune adjuvants, and cancer vaccines. First, the common synthesis methods are outlined for different types of chiral nanomaterials, as well as their chiral sources, optical properties, and potential biological applications. Then, the application of chiral nanomaterials are discussed in the field of vaccines with reference to the promotion of antigen presentation and activation of the immune system for tumor immunotherapy. Finally, the current obstacles and future research directions of chiral nanomaterials are revealed with regard to regulating the immune system.

mRNA vaccines and their delivery strategies: A journey from infectious diseases to cancer

mRNA vaccines have evolved as promising cancer therapies. These vaccines can encode tumor-allied antigens, thus enabling personalized treatment approaches. They can also target cancer-specific mutations and overcome immune evasion mechanisms. They manipulate the body's cellular functions to produce antigens, elicit immune responses, and suppress tumors by overcoming limitations associated with specific histocompatibility leukocyte antigen molecules. However, successfully delivering mRNA into target cells destroys a crucial challenge. Viral and nonviral vectors (lipid nanoparticles and cationic liposomes) have shown great capacity in protecting mRNA from deterioration and assisting in cellular uptake. Cell-penetrating peptides, hydrogels, polymer-based nanoparticles, and dendrimers have been investigated to increase the delivery efficacy and immunogenicity of mRNA. This comprehensive review explores the landscape of mRNA vaccines and their delivery platforms for cancer, addressing design considerations, diverse delivery strategies, and recent advancements. Overall, this review contributes to the progress of mRNA vaccines as an innovative strategy for effective cancer treatment.

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.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

Immunogenicity of Recombinant Lipid-Based Nanoparticle Vaccines: Danger Signal vs. Helping Hand

Infectious diseases are a predominant problem in human health. While the incidence of many pathogenic infections is controlled by vaccines, some pathogens still pose a challenging task for vaccine researchers. In order to face these challenges, the field of vaccine development has changed tremendously over the last few years. For non-replicating recombinant antigens, novel vaccine delivery systems that attempt to increase the immunogenicity by mimicking structural properties of pathogens are already approved for clinical applications. Lipid-based nanoparticles (LbNPs) of different natures are vesicles made of lipid layers with aqueous cavities, which may carry antigens and other biomolecules either displayed on the surface or encapsulated in the cavity. However, the efficacy profile of recombinant LbNP vaccines is not as high as that of live-attenuated ones. This review gives a compendious picture of two approaches that affect the immunogenicity of recombinant LbNP vaccines: (i) the incorporation of immunostimulatory agents and (ii) the utilization of pre-existing or promiscuous cellular immunity, which might be beneficial for the development of tailored prophylactic and therapeutic LbNP vaccine candidates.

Development of a novel multi-epitope mRNA vaccine candidate to combat HMPV virus

Human metapneumovirus (HMPV) is one of the main pathogens causing severe respiratory infections in children, as a common cause of immunodeficiency-related deaths in children and elderly individuals, the prevalence of HMPV has been showing an increasing trend during the last years. However, no vaccines or effective treatment plans are available currently. In this present, based on candidate proteins highly associated with viral virulence and has promising protective potential, we screened for immunodominant cytotoxic T cells, helper T cells, and Linear B-cell epitopes from the most promising candidate Fusion protein, together with G, SH, M, and M2. All epitopes were predicted to have strong antigenicity by Vaxijen and pose no potential toxicity, allergenicity, or hormonology to human proteins by Toxinpred, Allerpred, and Blast analysis, meanwhile, high conservancy is demanded to cover different subtypes. adjuvants β-defensin II and Pam2Cys was attached with EAAAK linkers to improve vaccine's efficiency. Then, calculation of physicochemical properties proved the protein vaccine as a product can stably exist in the human body. Besides, we assessed the docking between the vaccine and immune receptors to evaluate its ability to stimulate immune responses, and the dynamic simulation further confirmed that the vaccine can tightly bind with immune receptors, which approved that the construction has the potential to induce strong humoral and cellular immune response. Finally, the vaccine was constructed into a multi-epitope mRNA vaccine, the immune simulations suggest that this is a vaccine candidate for controlling HMPV infection.

Cancer/Testis Antigens as Targets for RNA-Based Anticancer Therapy

In the last few decades, RNA-based drugs have emerged as a promising candidate in the treatment of various diseases. The introduction of messenger RNA (mRNA) as a vaccine or therapeutic agent enables the production of almost any functional protein/peptide. The key to applying RNA therapy in clinical trials is developing safe and effective delivery systems. Exosomes and lipid nanoparticles (LNPs) have been exploited as promising vehicles for drug delivery. This review discusses the feasibility of exosomes and LNPs as vehicles for mRNA delivery. Cancer/testis antigens (CTAs) show restricted expression in normal tissues and widespread expression in cancer tissues. Many of these CTAs show expression in the sera of patients with cancers. These characteristics of CTAs make them excellent targets for cancer immunotherapy. This review summarizes the roles of CTAs in various life processes and current studies on mRNAs encoding CTAs. Clinical studies present the beneficial effects of mRNAs encoding CTAs in patients with cancers. This review highlight clinical studies employing mRNA-LNPs encoding CTAs.

Thiostrepton-Nanomedicine, a TLR9 Inhibitor, Attenuates Sepsis-Induced Inflammation in Mice

Sepsis is a life-threatening clinical condition caused by infection and transposition of pathogens and pathogen-associated molecular patterns (PAMPs) into the host bloodstream. During sepsis, activation of toll-like receptors (TLRs) on immune cells triggers the release of pro-inflammatory cytokines and overstimulates the production of vasodilatory mediators such as nitric oxide (NO). These vascular changes lead to widespread inflammation, tissue damage, multiple organ failure, and often death. New therapeutic options are urgently needed. To this end, thiostrepton (TST) has emerged as a candidate for sepsis treatment due to its action as an antibiotic and anti-inflammatory molecule (TLR7-9 inhibitor). Reports in the literature suggest that TLR9 inhibition substantially suppresses the excessive host inflammatory response and attenuates sepsis-induced mortality in the cecal ligation and puncture (CLP) murine model of sepsis. However, to the best of our knowledge, TST has never been directly tested as a therapeutic option for the management of sepsis, possibly due to its low water solubility and drug delivery issues. These facts prompted us to test the central hypothesis that TST encapsulated in phospholipid sterically stabilized micelles (TST-SSM) could be developed into a novel treatment for sepsis. Thus, using our published method of encapsulating the hydrophobic antibiotic TST-SSM, we evaluated the in vivo efficacy of TST-SSM nanomedicine in the murine model of polymicrobial sepsis. We found that TST-SSM increased the median survival of CLP-induced septic mice from 31 to 44 hr by reducing the bacterial burden in the blood and peritoneal lavage. Moreover, plasma levels of pro-inflammatory cytokines (interleukin 6 and tumor necrosis factor-alpha) and NO derivatives were also reduced, whereas renal and hepatic function biomarkers creatinine and aspartate transferase were significantly improved. In conclusion, we identified that TST-SSM nanomedicine has significant potential as a therapeutic agent for sepsis management, primarily due to its anti-inflammatory and antibiotic properties.