Therapeutic mRNA delivery to leukocytes

Research progress of mosquito-borne virus mRNA vaccines

In recent years, mRNA vaccines have emerged as a leading technology for preventing infectious diseases due to their rapid development and high immunogenicity. These vaccines encode viral antigens, which are translated into antigenic proteins within host cells, inducing both humoral and cellular immune responses. This review systematically examines the progress in mRNA vaccine research for major mosquito-borne viruses, including dengue virus, Zika virus, Japanese encephalitis virus, Chikungunya virus, yellow fever virus, Rift Valley fever virus, and Venezuelan equine encephalitis virus. Enhancements in mRNA vaccine design, such as improvements to the 5' cap structure, 5'UTR, open reading frame, 3'UTR, and polyadenylation tail, have significantly increased mRNA stability and translation efficiency. Additionally, the use of lipid nanoparticles and polymer nanoparticles has greatly improved the delivery efficiency of mRNA vaccines. Currently, mRNA vaccines against mosquito-borne viruses are under development and clinical trials, showing promising protective effects. Future research should continue to optimize vaccine design and delivery systems to achieve broad-spectrum and long-lasting protection against various mosquito-borne virus infections.

Evaluation of Lipid-Based Transfection in Primary Monocytes Within an Ex Vivo Whole-Blood Model

Transfection is a fundamental method in biomedical research to study intracellular molecular mechanisms by manipulating target protein expression. Various methods have been developed to deliver nucleic acids into the cells of interest in vitro, with chemical transfection by cationic lipids being the most widely used for RNA interference (RNAi). However, translating these in vitro results into in vivo remains a significant challenge. In this study, we established an ex vivo transfection model using cationic lipids in human whole blood. Three different lipid-based reagents were evaluated regarding toxicity, transfection efficiency, and immunogenicity across leukocyte populations using spectral flow cytometry. CD14+ monocytes were identified as the primary population to be transfected by cationic lipids in whole blood. To assess immunogenicity, the monocyte-specific activation markers CD80 and human leukocyte antigen DR isotype (HLA-DR) were analyzed upon transfection. Our results demonstrated that Lipofectamine RNAiMAX outperforms the other two reagents, showing low toxicity and high transfection efficiency in combination with a minimal potential for monocyte activation. Functional knockdown experiments using siRNA targeting CIITA and the microRNA mir-3972 targeting HLA-DRA showed dose-dependent suppression in HLA-DR expression. This study provides the framework for preliminary testing of RNAi in a physiologically relevant ex vivo model, enabling assessment of key endpoints such as toxicity, transfection efficiency, and immune activation potential of gene delivery systems.

Emerging advances in nano-biomaterial assisted amyloid beta chimeric antigen receptor macrophages (CAR-M) therapy: reducing plaque burden in Alzheimer's disease

Alzheimer's disease is the most common form, accounting for 60-70% of 55 million dementia cases. Even though the precise pathophysiology of AD is not completely understood, clinical trials focused on antibodies targeting aggregated forms of β amyloid (Aβ) have demonstrated that reducing amyloid plaques can arrest cognitive decline in patients in the early stages of AD. In this study, we provide an overview of current research and innovations for controlled release from nano-biomaterial-assisted chimeric antigen receptor macrophage (CAR-M) therapeutic strategies targeted at AD. Nano-bio materials, such as iron-oxide nanoparticles (IONPs), can be made selectively (Hp-Hb/mannose) to bind and take up Aβ plaques like CAR-M cells. By using nano-bio materials, both the delivery and stability of CAR-M cells in brain tissue can be improved to overcome the barriers of the BBB and enhance therapeutic effects. By enhancing the targeting capabilities and stability of CAR-M cells, mRNA-loaded nano-biomaterials can significantly improve the efficacy of immunotherapy for plaque reduction in AD. This novel strategy holds promise for translating preclinical successes into clinical applications, potentially revolutionising the management of AD.

ADAMTS12 serves as a novel prognostic biomarker and promotes proliferation and invasion in gastric cancer

Gastric cancer (GC) remains a prevalent and aggressive malignancy with a poor prognosis. This study aimed to identify diagnostic and prognostic biomarkers while exploring their potential functions in GC. A total of 598 upregulated and 506 downregulated genes were identified in GC patients. Among these, survival-related differentially expressed genes (DEGs), including ADAMTS12, F5, and VCAN, were highlighted. Pan-cancer analyses revealed their dysregulation across multiple tumor types. A novel prognostic signature, incorporating ADAMTS12 and F5, effectively stratified GC patients into low- and high-risk groups, demonstrating significant differences in overall survival and robust predictive performance. ADAMTS12, strongly associated with advanced clinical stages and poor prognosis, was validated in an independent cohort and exhibited promising diagnostic potential. RT-PCR and western blot analyses confirmed its high expression in GC tissues and cell lines. Functional assays further demonstrated that ADAMTS12 promotes GC cell proliferation and invasion. In summary, this study provides critical insights into the molecular landscape of GC, offering a potential prognostic tool and therapeutic target.

Development of mRNA Lipid Nanoparticles: Targeting and Therapeutic Aspects

Lipid nanoparticles (LNPs) have emerged as leading non-viral carriers for messenger RNA (mRNA) delivery in clinical applications. Overcoming challenges in safe and effective mRNA delivery to target tissues and cells, along with controlling release from the delivery vehicle, remains pivotal in mRNA-based therapies. This review elucidates the structure of LNPs, the mechanism for mRNA delivery, and the targeted delivery of LNPs to various cells and tissues, including leukocytes, T-cells, dendritic cells, Kupffer cells, hepatic endothelial cells, and hepatic and extrahepatic tissues. Here, we discuss the applications of mRNA-LNP vaccines for the prevention of infectious diseases and for the treatment of cancer and various genetic diseases. Although challenges remain in terms of delivery efficiency, specific tissue targeting, toxicity, and storage stability, mRNA-LNP technology holds extensive potential for the treatment of diseases.

The paths toward non-viral CAR-T cell manufacturing: A comprehensive review of state-of-the-art methods

Although CAR-T cell therapy has emerged as a game-changer in cancer immunotherapy several bottlenecks limit its widespread use as a front-line therapy. Current protocols for the production of CAR-T cells rely mainly on the use of lentiviral/retroviral vectors. Nevertheless, according to the safety concerns around the use of viral vectors, there are several regulatory hurdles to their clinical use. Large-scale production of viral vectors under "Current Good Manufacturing Practice" (cGMP) involves rigorous quality control assessments and regulatory requirements that impose exorbitant costs on suppliers and as a result, lead to a significant increase in the cost of treatment. Pursuing an efficient non-viral method for genetic modification of immune cells is a hot topic in cell-based gene therapy. This study aims to investigate the current state-of-the-art in non-viral methods of CAR-T cell manufacturing. In the first part of this study, after reviewing the advantages and disadvantages of the clinical use of viral vectors, different non-viral vectors and the path of their clinical translation are discussed. These vectors include transposons (sleeping beauty, piggyBac, Tol2, and Tc Buster), programmable nucleases (ZFNs, TALENs, and CRISPR/Cas9), mRNA, plasmids, minicircles, and nanoplasmids. Afterward, various methods for efficient delivery of non-viral vectors into the cells are reviewed.

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.

Overcoming Resistance Mechanisms to Immune Checkpoint Inhibitors: Leveraging the Anti-Tumor Immune Response

As far back as 3000 years ago, the immune system was observed to play a role in mediating tumor regression. Since then, many strategies have been developed to leverage the anti-tumor immune response. However, while many patients respond to ICIs up front some do not, and many of those that do eventually experience tumor progression. Currently, there are several predictive biomarkers of the immune checkpoint inhibitor response; however, no one test appears to be universally predictive and their application varies by disease site. There are many ways in which cancer cells develop primary or acquired resistance to immune checkpoint inhibitors. Efforts to reverse resistance include ways to combat T cell exhaustion, reprogram the tumor microenvironment, increase the availability of tumor neo-antigens, target alternative immune checkpoints, restore a normal/healthy patient gut microbiome, oncolytic viruses and tumor vaccines. The most studied and most promising methods include combining ICIs with therapies targeting alternative immune checkpoints and restoring a normal/healthy patient gut microbiome. This review will discuss T cell-mediated immunity, how this is leveraged by modern immunotherapy to treat cancer and mechanisms of immune checkpoint inhibitor resistance, while highlighting strategies to overcome primary and secondary resistance mechanisms.

Lipid Nanoparticle (LNP) Enables mRNA Delivery for Cancer Therapy

Messenger RNA (mRNA) has received great attention in the prevention and treatment of various diseases due to the success of coronavirus disease 2019 (COVID-19) mRNA vaccines (Comirnaty and Spikevax). To meet the therapeutic purpose, it is required that mRNA must enter the target cells and express sufficient proteins. Therefore, the development of effective delivery systems is necessary and crucial. Lipid nanoparticle (LNP) represents a remarkable vehicle that has indeed accelerated mRNA applications in humans, as several mRNA-based therapies have already been approved or are in clinical trials. In this review, the focus is on mRNA-LNP-mediated anticancer therapy. It summarizes the main development strategies of mRNA-LNP formulations, discusses representative therapeutic approaches in cancer, and points out current challenges and possible future directions of this research field. It is hoped that these delivered messages can help further improve the application of mRNA-LNP technology in cancer therapy.

Targeting cancer with mRNA-lipid nanoparticles: key considerations and future prospects

Harnessing mRNA-lipid nanoparticles (LNPs) to treat patients with cancer has been an ongoing research area that started before these versatile nanoparticles were successfully used as COVID-19 vaccines. Currently, efforts are underway to harness this platform for oncology therapeutics, mainly focusing on cancer vaccines targeting multiple neoantigens or direct intratumoural injections of mRNA-LNPs encoding pro-inflammatory cytokines. In this Review, we describe the opportunities of using mRNA-LNPs in oncology applications and discuss the challenges for successfully translating the findings of preclinical studies of these nanoparticles into the clinic. We critically appraise the potential of various mRNA-LNP targeting and delivery strategies, considering physiological, technological and manufacturing challenges. We explore these approaches in the context of the potential clinical applications best suited to each approach and highlight the obstacles that currently need to be addressed to achieve these applications. Finally, we provide insights from preclinical and clinical studies that are leading to this powerful platform being considered the next frontier in oncology treatment.

Nanomaterials for mRNA-based therapeutics: Challenges and opportunities

Messenger RNA (mRNA) holds great potential in developing immunotherapy, protein replacement, and genome editing. In general, mRNA does not have the risk of being incorporated into the host genome and does not need to enter the nucleus for transfection, and it can be expressed even in nondividing cells. Therefore, mRNA-based therapeutics provide a promising strategy for clinical treatment. However, the efficient and safe delivery of mRNA remains a crucial constraint for the clinical application of mRNA therapeutics. Although the stability and tolerability of mRNA can be enhanced by directly retouching the mRNA structure, there is still an urgent need to improve the delivery of mRNA. Recently, significant progress has been made in nanobiotechnology, providing tools for developing mRNA nanocarriers. Nano-drug delivery system is directly used for loading, protecting, and releasing mRNA in the biological microenvironment and can be used to stimulate the translation of mRNA to develop effective intervention strategies. In the present review, we summarized the concept of emerging nanomaterials for mRNA delivery and the latest progress in enhancing the function of mRNA, primarily focusing on the role of exosomes in mRNA delivery. Moreover, we outlined its clinical applications so far. Finally, the key obstacles of mRNA nanocarriers are emphasized, and promising strategies to overcome these obstacles are proposed. Collectively, nano-design materials exert functions for specific mRNA applications, provide new perception for next-generation nanomaterials, and thus revolution of mRNA technology.

Hydrogel armed with Bmp2 mRNA-enriched exosomes enhances bone regeneration

BACKGROUND

Sustained release of bioactive BMP2 (bone morphogenetic protein-2) is important for bone regeneration, while the intrinsic short half-life of BMP2 at protein level cannot meet the clinical need. In this study, we aimed to design Bmp2 mRNA-enriched engineered exosomes, which were then loaded into specific hydrogel to achieve sustained release for more efficient and safe bone regeneration.

RESULTS

Bmp2 mRNA was enriched into exosomes by selective inhibition of translation in donor cells, in which NoBody (non-annotated P-body dissociating polypeptide, a protein that inhibits mRNA translation) and modified engineered BMP2 plasmids were co-transfected. The derived exosomes were named Exo^BMP2+NoBody. In vitro experiments confirmed that Exo^BMP2+NoBody had higher abundance of Bmp2 mRNA and thus stronger osteogenic induction capacity. When loaded into GelMA hydrogel via ally-L-glycine modified CP05 linker, the exosomes could be slowly released and thus ensure prolonged effect of BMP2 when endocytosed by the recipient cells. In the in vivo calvarial defect model, Exo^BMP2+NoBody-loaded GelMA displayed great capacity in promoting bone regeneration.

CONCLUSIONS

Together, the proposed Exo^BMP2+NoBody-loaded GelMA can provide an efficient and innovative strategy for bone regeneration.

Highly efficient mRNA delivery with nonlinear microfluidic cell stretching for cellular engineering

In the past few years, messenger RNA (mRNA) has emerged as a promising therapeutic agent for the treatment and prevention of various diseases. Clinically, mRNA-based drugs have been used for cancer immunotherapy, infectious diseases, and genomic disorders. To maximize the therapeutic efficacy of mRNA, the exact amount of mRNAs must be delivered to the target locations without degradation; however, traditional delivery modalities, such as lipid carriers and electroporation, are suboptimal because of their high cost, cell-type sensitivity, low scalability, transfection/delivery inconsistency, and/or loss of cell functionality. Therefore, new effective and stable delivery methods are required. Accordingly, we present a novel nonlinear microfluidic cell stretching (μ-cell stretcher) platform that leverages viscoelastic fluids, i.e., methylcellulose (MC) solutions, and cell mechanoporation for highly efficient and robust intracellular mRNA delivery. In the proposed platform, cells suspended in MC solutions with mRNAs were injected into a microchannel where they rapidly passed through a single constriction. Owing to the use of viscoelastic MC solutions, a high shear force was applied to the cells, effectively creating transient nanopores. This feature allows mRNAs to be effectively internalized through generated membrane discontinuities. Using this platform, high delivery efficiency (∼97%), high throughput (∼3.5 × 10⁵ cells per min), cell-type-/cargo-size-insensitive delivery, simple operation (single-step), low analyte consumption, low-cost operation (<$1), and nearly clogging-free operation were demonstrated, demonstrating the high potential of the proposed platform for application in mRNA-based cellular engineering research.

Development and applications of mRNA treatment based on lipid nanoparticles

Nucleic acid-based therapies such as messenger RNA have the potential to revolutionize modern medicine and enhance the performance of existing pharmaceuticals. The key challenges of mRNA-based therapies are delivering the mRNA safely and effectively to the target tissues and cells and controlling its release from the delivery vehicle. Lipid nanoparticles (LNPs) have been widely studied as drug carriers and are considered to be state-of-the-art technology for nucleic acid delivery. In this review, we begin by presenting the advantages and mechanisms of action of mRNA therapeutics. Then we discuss the design of LNP platforms based on ionizable lipids and the applications of mRNA-LNP vaccines for prevention of infectious diseases and for treatment of cancer and various genetic diseases. Finally, we describe the challenges and future prospects of mRNA-LNP therapeutics.

Directing the Way-Receptor and Chemical Targeting Strategies for Nucleic Acid Delivery

Nucleic acid therapeutics have shown great potential for the treatment of numerous diseases, such as genetic disorders, cancer and infections. Moreover, they have been successfully used as vaccines during the COVID-19 pandemic. In order to unfold full therapeutical potential, these nano agents have to overcome several barriers. Therefore, directed transport to specific tissues and cell types remains a central challenge to receive carrier systems with enhanced efficiency and desired biodistribution profiles. Active targeting strategies include receptor-targeting, mediating cellular uptake based on ligand-receptor interactions, and chemical targeting, enabling cell-specific delivery as a consequence of chemically and structurally modified carriers. With a focus on synthetic delivery systems including polyplexes, lipid-based systems such as lipoplexes and lipid nanoparticles, and direct conjugates optimized for various types of nucleic acids (DNA, mRNA, siRNA, miRNA, oligonucleotides), we highlight recent achievements, exemplified by several nucleic acid drugs on the market, and discuss challenges for targeted delivery to different organs such as brain, eye, liver, lung, spleen and muscle in vivo.

Novel bionic inspired nanosystem construction for precise delivery of mRNA

The intracellular delivery of messenger (m)RNA holds great potential for the discovery and development of vaccines and therapeutics. Yet, in many applications, a major obstacle to clinical translation of mRNA therapy is the lack of efficient strategy to precisely deliver RNA sequence to liver tissues and cells. In this study, we synthesized virus-like mesoporous silica (V-SiO₂) nanoparticles for effectively deliver the therapeutic RNA. Then, the cationic polymer polyethylenimine (PEI) was included for the further silica surface modification (V-SiO₂-P). Negatively charged mRNA motifs were successfully linked on the surface of V-SiO₂ through electrostatic interactions with PEI (m@V-SiO₂-P). Finally, the supported lipid bilayer (LB) was completely wrapped on the bionic inspired surface of the nanoparticles (m@V-SiO₂-P/LB). Importantly, we found that, compared with traditional liposomes with mRNA loading (m@LNPs), the V-SiO₂-P/LB bionic-like morphology effectively enhanced mRNA delivery effect to hepatocytes both in vitro and in vivo, and PEI modification concurrently promoted mRNA binding and intracellular lysosomal escape. Furthermore, m@V-SiO₂-P increased the blood circulation time (t_1/2 = 7 h) to be much longer than that of the m@LNPs (4.2 h). Understanding intracellular delivery mediated by the V-SiO₂-P/LB nanosystem will inspire the next-generation of highly efficient and effective mRNA therapies. In addition, the nanosystem can also be applied to the oral cavity, forehead, face and other orthotopic injections.

Freeze-drying for the preservation of immunoengineering products

Immunoengineering technologies harness the power of immune system modulators such as monoclonal antibodies, cytokines, and vaccines to treat myriad diseases. Immunoengineering innovations have showed great promise in various practices including oncology, infectious disease, autoimmune diseases, and transplantation. Despite the countless successes, the majority of immunoengineering products contain active moieties that are prone to instability. The current review aims to feature freeze-drying as a robust and scalable solution to the inherent stability challenges in immunoengineering products by preventing the active moiety from degradation. Furthermore, this review describes the stability issues related to immunoengineering products and the utility of the lyophilization process to preserve the integrity and efficacy of immunoengineering tools ranging from biologics to nanoparticle-based vaccines. The concept of the freeze-drying process is described highlighting the quality by design (QbD) for robust process optimization. Case studies of lyophilized immunoengineering technologies and relevant clinical studies using immunoengineering products are discussed.

Sonoporation of Immune Cells: Heterogeneous Impact on Lymphocytes, Monocytes and Granulocytes

Microbubble-mediated ultrasound (MB-US) can be used to realize sonoporation and, in turn, facilitate the transfection of leukocytes in the immune system. Nevertheless, the bio-effects that can be induced by MB-US exposure on leukocytes have not been adequately studied, particularly for different leukocyte lineage subsets with distinct cytological characteristics. Here, we describe how that same set of MB-US exposure conditions would induce heterogeneous bio-effects on the three main leukocyte subsets: lymphocytes, monocytes and granulocytes. MB-US exposure was delivered by applying 1-MHz pulsed ultrasound (0.50-MPa peak negative pressure, 10% duty cycle, 30-s exposure period) in the presence of microbubbles (1:1 cell-to-bubble ratio); sonoporated and non-viable leukocytes were respectively labeled using calcein and propidium iodide. Flow cytometry was then performed to classify leukocytes into their corresponding subsets and to analyze each subset's post-exposure viability, sonoporation rate, uptake characteristics and morphology. Results revealed that, when subjected to MB-US exposure, granulocytes experienced the highest loss of viability (64.0 ± 11.0%) and the lowest sonoporation rate (6.3 ± 2.5%), despite maintaining their size and granularity. In contrast, lymphocytes exhibited the lowest loss of viability (20.9 ± 7.0%), while monocytes had the highest sonoporation rate (24.1 ± 13.6%). For these two sonoporated leukocyte subsets, their cell size and granularity were found to be reduced. Also, they exhibited graded levels of calcein uptake, whereas sonoporated granulocytes achieved only mild calcein uptake. These heterogeneous bio-effects should be accounted for when using MB-US and sonoporation in immunomodulation applications.

The Past, Present, and Future of Non-Viral CAR T Cells

Adoptive transfer of chimeric antigen receptor (CAR) T lymphocytes is a powerful technology that has revolutionized the way we conceive immunotherapy. The impressive clinical results of complete and prolonged response in refractory and relapsed diseases have shifted the landscape of treatment for hematological malignancies, particularly those of lymphoid origin, and opens up new possibilities for the treatment of solid neoplasms. However, the widening use of cell therapy is hampered by the accessibility to viral vectors that are commonly used for T cell transfection. In the era of messenger RNA (mRNA) vaccines and CRISPR/Cas (clustered regularly interspaced short palindromic repeat-CRISPR-associated) precise genome editing, novel and virus-free methods for T cell engineering are emerging as a more versatile, flexible, and sustainable alternative for next-generation CAR T cell manufacturing. Here, we discuss how the use of non-viral vectors can address some of the limitations of the viral methods of gene transfer and allow us to deliver genetic information in a stable, effective and straightforward manner. In particular, we address the main transposon systems such as Sleeping Beauty (SB) and piggyBac (PB), the utilization of mRNA, and innovative approaches of nanotechnology like Lipid-based and Polymer-based DNA nanocarriers and nanovectors. We also describe the most relevant preclinical data that have recently led to the use of non-viral gene therapy in emerging clinical trials, and the related safety and efficacy aspects. We will also provide practical considerations for future trials to enable successful and safe cell therapy with non-viral methods for CAR T cell generation.

mRNA-based therapeutics: powerful and versatile tools to combat diseases

The therapeutic use of messenger RNA (mRNA) has fueled great hope to combat a wide range of incurable diseases. Recent rapid advances in biotechnology and molecular medicine have enabled the production of almost any functional protein/peptide in the human body by introducing mRNA as a vaccine or therapeutic agent. This represents a rising precision medicine field with great promise for preventing and treating many intractable or genetic diseases. In addition, in vitro transcribed mRNA has achieved programmed production, which is more effective, faster in design and production, as well as more flexible and cost-effective than conventional approaches that may offer. Based on these extraordinary advantages, mRNA vaccines have the characteristics of the swiftest response to large-scale outbreaks of infectious diseases, such as the currently devastating pandemic COVID-19. It has always been the scientists’ desire to improve the stability, immunogenicity, translation efficiency, and delivery system to achieve efficient and safe delivery of mRNA. Excitingly, these scientific dreams have gradually been realized with the rapid, amazing achievements of molecular biology, RNA technology, vaccinology, and nanotechnology. In this review, we comprehensively describe mRNA-based therapeutics, including their principles, manufacture, application, effects, and shortcomings. We also highlight the importance of mRNA optimization and delivery systems in successful mRNA therapeutics and discuss the key challenges and opportunities in developing these tools into powerful and versatile tools to combat many genetic, infectious, cancer, and other refractory diseases.

Physical and chemical advances of synthetic delivery vehicles to enhance mRNA vaccine efficacy

The successful translation of mRNA vaccines slows down the spread of viral infectious diseases, which may be accomplished by developing novel chemically modified nucleotides (or nucleosides) and highly efficient, safe mRNA delivery vehicles. Delivery vehicles protect vulnerable antigen mRNA and increase the uptake of mRNA into antigen-presenting cells in the peripheral tissue or lymph nodes. This review introduces essential characteristics of mRNA vaccines (e.g., particle sizes, colloidal stability, surface charges/endosomal escape ability, and ligand conjugation) that may be used to generate high immune responses against foreign antigens. The significance and mechanism of each characteristic are described based on the results obtained from in vitro and in vivo studies. We also discuss the development of next generation delivery vehicles for future mRNA vaccines.

A polyphenol-assisted IL-10 mRNA delivery system for ulcerative colitis

With the development of synthesis technology, modified messenger RNA (mRNA) has emerged as a novel category of therapeutic agents for a broad of diseases. However, effective intracellular delivery of mRNA remains challenging, especially for its sensitivity to enzymatic degradation. Here, we propose a polyphenol-assisted handy delivery strategy for efficient in vivo delivery of IL-10 mRNA. IL-10 mRNA binds to polyphenol ellagic acid through supramolecular binding to yield a negatively charged core, followed by complexing with linear polyetherimide and coating with bilirubin-modified hyaluronic acid to obtain a layer-by-layer nanostructure. The nanostructure specifically up-regulated the level of IL-10, effectively inhibited the expression of inflammatory factors, promoted mucosal repair, protected colonic epithelial cells against apoptosis, and exerted potent therapeutic efficacy in dextran sulfate sodium salt-induced acute and chronic murine models of colitis. The designed delivery system without systemic toxicity has the potential to facilitate the development of a promising platform for mRNA delivery in ulcerative colitis treatment.

Delivery of mRNA for regulating functions of immune cells

Abnormal immune cell functions are commonly related to various diseases, including cancer, autoimmune diseases, and infectious diseases. Messenger RNA (mRNA)-based therapy can regulate the functions of immune cells or assign new functions to immune cells, thereby generating therapeutic immune responses to treat these diseases. However, mRNA is unstable in physiological environments and can hardly enter the cytoplasm of target cells; thus, effective mRNA delivery systems are critical for developing mRNA therapy. The two mRNA vaccines of Pfizer-BioNTech and Moderna have demonstrated that lipid nanoparticles (LNPs) can deliver mRNA into dendritic cells (DCs) to induce immunization against severe acute respiratory syndrome coronavirus 2, which opened the floodgates to the development of mRNA therapy. Apart from DCs, other immune cells are promising targets for mRNA therapy. This review summarized the barriers to mRNA delivery and advances in mRNA delivery for regulating the functions of different immune cells.

Intravesical delivery of KDM6A-mRNA via mucoadhesive nanoparticles inhibits the metastasis of bladder cancer

This study provides proof-of-principle evidence for intravesical delivery of messenger RNA (mRNA) via a mucoadhesive nanoparticle (NP) strategy and reveals the therapeutic potential of KDM6A in treating bladder cancer metastasis, which remains difficult due to the physiological bladder barriers. The mucoadhesive NPs could protect loaded mRNA, prolong exposure of mRNA in disease sites, and benefit the penetration and effective expression, which all represent challenging hurdles for intravesical delivery of mRNA therapeutics. mRNA local delivery can also avoid potential toxicity issues via systemic delivery and unwanted protein expression throughout the body. We expect this mucoadhesive mRNA nanotechnology can be useful for the effective up-regulation of targeted proteins in bladder tissues in situ for both mechanistic understanding and translational study of bladder-related diseases.

Lysine-specific demethylase 6A (KDM6A), also named UTX, is frequently mutated in bladder cancer (BCa). Although known as a tumor suppressor, KDM6A’s therapeutic potential in the metastasis of BCa remains elusive. It also remains difficult to fulfill the effective up-regulation of KDM6A levels in bladder tumor tissues in situ to verify its potential in treating BCa metastasis. Here, we report a mucoadhesive messenger RNA (mRNA) nanoparticle (NP) strategy for the intravesical delivery of KDM6A-mRNA in mice bearing orthotopic Kdm6a-null BCa and show evidence of KDM6A’s therapeutic potential in inhibiting the metastasis of BCa. Through this mucoadhesive mRNA NP strategy, the exposure of KDM6A-mRNA to the in situ BCa tumors can be greatly prolonged for effective expression, and the penetration can be also enhanced by adhering to the bladder for sustained delivery. This mRNA NP strategy is also demonstrated to be effective for combination cancer therapy with other clinically approved drugs (e.g., elemene), which could further enhance therapeutic outcomes. Our findings not only report intravesical delivery of mRNA via a mucoadhesive mRNA NP strategy but also provide the proof-of-concept for the usefulness of these mRNA NPs as tools in both mechanistic understanding and translational study of bladder-related diseases.

mRNA, a Revolution in Biomedicine

The perspective of using messenger RNA (mRNA) as a therapeutic molecule first faced some uncertainties due to concerns about its instability and the feasibility of large-scale production. Today, given technological advances and deeper biomolecular knowledge, these issues have started to be addressed and some strategies are being exploited to overcome the limitations. Thus, the potential of mRNA has become increasingly recognized for the development of new innovative therapeutics, envisioning its application in immunotherapy, regenerative medicine, vaccination, and gene editing. Nonetheless, to fully potentiate mRNA therapeutic application, its efficient production, stabilization and delivery into the target cells are required. In recent years, intensive research has been carried out in this field in order to bring new and effective solutions towards the stabilization and delivery of mRNA. Presently, the therapeutic potential of mRNA is undoubtedly recognized, which was greatly reinforced by the results achieved in the battle against the COVID-19 pandemic, but there are still some issues that need to be improved, which are critically discussed in this review.

The significance of bioengineered nanoplatforms against SARS-CoV-2: From detection to genome editing

COVID-19 outbreak can impose serious negative impacts on the infrastructures of societies including the healthcare systems. Despite the increasing research efforts, false positive or negative results that may be associated with serologic or even RT-PCR tests, inappropriate or variable immune response, and high rates of mutations in coronavirus may negatively affect virus detection process and effectiveness of the vaccines or drugs in development. Nanotechnology-based research attempts via developing state-of-the-art techniques such as nanomechatronics ones and advanced materials including the sensors for detecting the pathogen loads at very low concentrations or site-specific delivery of therapeutics, and real-time protections against the pandemic outbreaks by nanorobots can provide outstanding biomedical breakthroughs. Considering the unique characteristics of pathogens particularly the newly-emerged ones and avoiding the exaggerated optimism or simplistic views on the prophylactic and therapeutic approaches including the one-size-fits-all ones or presenting multiple medications that may be associated with synergistic toxicities rather than enhanced efficiencies might pave the way towards the development of more appropriate treatment strategies with reduced safety concerns. This paper highlights the significance of nanoplatforms against the viral disorders and their capabilities of genome editing that may facilitate taking more appropriate measures against SARS-CoV-2.

Future considerations for the mRNA-lipid nanoparticle vaccine platform

Vaccines based on mRNA-containing lipid nanoparticles (LNPs) pioneered by Katalin Karikó and Drew Weissman at the University of Pennsylvania are a promising new vaccine platform used by two of the leading vaccines against coronavirus disease in 2019 (COVID-19). However, there are many questions regarding their mechanism of action in humans that remain unanswered. Here we consider the immunological features of LNP components and off-target effects of the mRNA, both of which could increase the risk of side effects. We suggest ways to mitigate these potential risks by harnessing dendritic cell (DC) biology.

Non-viral transfection technologies for next-generation therapeutic T cell engineering

Genetically engineered T cells have sparked interest in advanced cancer treatment, reaching a milestone in 2017 with two FDA-approvals for CD19-directed chimeric antigen receptor (CAR) T cell therapeutics. It is becoming clear that the next generation of CAR T cell therapies will demand more complex engineering strategies and combinations thereof, including the use of revolutionary gene editing approaches. To date, manufacturing of CAR T cells mostly relies on γ-retroviral or lentiviral vectors, but their use is associated with several drawbacks, including safety issues, high manufacturing cost and vector capacity constraints. Non-viral approaches, including membrane permeabilization and carrier-based techniques, have therefore gained a lot of interest to replace viral transductions in the manufacturing of T cell therapeutics. This review provides an in-depth discussion on the avid search for alternatives to viral vectors, discusses key considerations for T cell engineering technologies, and provides an overview of the emerging spectrum of non-viral transfection technologies for T cells. Strengths and weaknesses of each technology will be discussed in relation to T cell engineering. Altogether, this work emphasizes the potential of non-viral transfection approaches to advance the next-generation of genetically engineered T cells.

Nanobiomaterial-based vaccination immunotherapy of cancer

Cancer immunotherapies including cancer vaccines, immune checkpoint blockade or chimeric antigen receptor T cells have been exploited as the attractive treatment modalities in recent years. Among these approaches, cancer vaccines that designed to deliver tumor antigens and adjuvants to activate the antigen presenting cells (APCs) and induce antitumor immune responses, have shown significant efficacy in inhibiting tumor growth, preventing tumor relapse and metastasis. Despite the potential of cancer vaccination strategies, the therapeutic outcomes in preclinical trials are failed to promote their clinical translation, which is in part due to their inefficient vaccination cascade of five critical steps: antigen identification, antigen encapsulation, antigen delivery, antigen release and antigen presentation to T cells. In recent years, it has been demonstrated that various nanobiomaterials hold great potential to enhance cancer vaccination cascade and improve their antitumor performance and reduce the off-target effect. We summarize the cutting-edge advances of nanobiomaterials-based vaccination immunotherapy of cancer in this review. The various cancer nanovaccines including antigen peptide/adjuvant-based nanovaccines, nucleic acid-based nanovaccines as well as biomimetic nanobiomaterials-based nanovaccines are discussed in detail. We also provide some challenges and perspectives associated with the clinical translation of cancer nanovaccines.

Mechanisms of resistance to immune checkpoint inhibitors and strategies to reverse drug resistance in lung cancer

In recent years, the research of immune checkpoint inhibitors has made a great breakthrough in lung cancer treatment. Currently, a variety of immune checkpoint inhibitors have been applied into clinical practice, including antibodies targeting the programmed cell death-1, programmed cell death-ligand 1, and cytotoxic T-lymphocyte antigen 4, and so on. However, not all patients can benefit from the treatment. Abnormal antigen presentation, functional gene mutation, tumor microenvironment, and other factors can lead to primary or secondary resistance. In this paper, we reviewed the molecular mechanism of immune checkpoint inhibitor resistance and various combination strategies to overcome resistance, in order to expand the beneficial population and enable precision medicine.

Intracellular Delivery of mRNA in Adherent and Suspension Cells by Vapor Nanobubble Photoporation

Efficient and safe cell engineering by transfection of nucleic acids remains one of the long-standing hurdles for fundamental biomedical research and many new therapeutic applications, such as CAR T cell-based therapies. mRNA has recently gained increasing attention as a more safe and versatile alternative tool over viral- or DNA transposon-based approaches for the generation of adoptive T cells. However, limitations associated with existing nonviral mRNA delivery approaches hamper progress on genetic engineering of these hard-to-transfect immune cells. In this study, we demonstrate that gold nanoparticle-mediated vapor nanobubble (VNB) photoporation is a promising upcoming physical transfection method capable of delivering mRNA in both adherent and suspension cells. Initial transfection experiments on HeLa cells showed the importance of transfection buffer and cargo concentration, while the technology was furthermore shown to be effective for mRNA delivery in Jurkat T cells with transfection efficiencies up to 45%. Importantly, compared to electroporation, which is the reference technology for nonviral transfection of T cells, a fivefold increase in the number of transfected viable Jurkat T cells was observed. Altogether, our results point toward the use of VNB photoporation as a more gentle and efficient technology for intracellular mRNA delivery in adherent and suspension cells, with promising potential for the future engineering of cells in therapeutic and fundamental research applications.

mRNA Vaccine Era-Mechanisms, Drug Platform and Clinical Prospection

Messenger ribonucleic acid (mRNA)-based drugs, notably mRNA vaccines, have been widely proven as a promising treatment strategy in immune therapeutics. The extraordinary advantages associated with mRNA vaccines, including their high efficacy, a relatively low severity of side effects, and low attainment costs, have enabled them to become prevalent in pre-clinical and clinical trials against various infectious diseases and cancers. Recent technological advancements have alleviated some issues that hinder mRNA vaccine development, such as low efficiency that exist in both gene translation and in vivo deliveries. mRNA immunogenicity can also be greatly adjusted as a result of upgraded technologies. In this review, we have summarized details regarding the optimization of mRNA vaccines, and the underlying biological mechanisms of this form of vaccines. Applications of mRNA vaccines in some infectious diseases and cancers are introduced. It also includes our prospections for mRNA vaccine applications in diseases caused by bacterial pathogens, such as tuberculosis. At the same time, some suggestions for future mRNA vaccine development about storage methods, safety concerns, and personalized vaccine synthesis can be found in the context.

Emerging Concepts of Nanobiotechnology in mRNA Delivery

Introducing mRNA into cells has attracted intense interest for diverse applications; however, success requires delivery solutions. Engineered nanomaterials have been applied as mRNA nanocarriers; their functions are designed mainly as delivery vehicles, but rarely in regulation of the protein translation. Recently, progress in nanobiotechnology has shifted the design principle of mRNA nanocarriers from simple delivery tools to translation modulators. Here, we review the emerging concepts of nanomaterials regulating mRNA translation and recent progress in mRNA delivery. Designer nanomaterials providing integrated functions for specific mRNA applications are also reviewed to provide insights for the design of next-generation nanomaterials to revolutionize mRNA technology.

Efficient Colorectal Cancer Gene Therapy with IL-15 mRNA Nanoformulation

Immunogene therapy is a novel method for the treatment of colorectal cancer. Cytokine IL-15 has exhibited therapeutic anticancer potential due to its immune-stimulation property. However, conventional IL-15-based cancer gene therapy studies have been performed using the plasmid DNA form, which has potential shortcomings including weak delivery efficiency and backbone effect. In this study, an IL-15 immunogene therapy study for colon cancer using in vitro transcript mRNA is described. A protamine/liposome system (CLPP) is developed to provide efficient condensation and delivery capacity for in vivo mRNA transportation. They demonstrated that the prepared CLPP system could deliver the IL-15-encoding mRNA into C26 cells with high efficacy. The secretory expressed IL-15 cytokine by the C26 cells successfully produced lymphocyte stimulation and triggered anticancer cytotoxicity upon cancer cells in vitro. Local or systemic administration of the CLPP/mIL-15 complex exhibited obvious inhibition effects on multiple C26 murine colon cancer models with inhibition rates of up to 70% in the C26 abdominal cavity metastasis tumor model, 55% in the subcutaneous model, and 69% in the pulmonary metastasis model, demonstrating high efficacy and safety. These results successfully demonstrated the high therapeutic potential of the CLPP/mIL-15 complex for colorectal cancer immunogene therapy.

Combined hybrid structure of siRNA tailed IVT mRNA (ChriST mRNA) for enhancing DC maturation and subsequent anticancer T cell immunity

RNA therapeutics have received much attention in the development of anti-cancer therapies. Among them, synthetic mRNA (IVT mRNA) was investigated for cancer immunotherapy due to its abilities to express tumor associated antigens with stimulation of immune responses in dendritic cells (DCs). Despite of its great potential, several hurdles were remained such as insufficient immune stimulation and DC maturation. In this study, we aimed to present a novel IVT mRNA that can simultaneously express tumor associated antigens while suppress STAT3 proteins. Combined functions of siRNA and IVT mRNA were investigated and the hybrid structure of siRNA tailed mRNA (ChriST mRNA) was developed. We prepared the ChriST mRNA by employing polyA tail structures with RNAi sequences at the 3' end of mRNA. Complementary strands were annealed to form duplex siRNA structure to induce STAT3 gene silencing. In addition, a hybrid structure of DNA/RNA was introduced into the ChriST mRNA between polyA tail and RNAi sequences. It was expected that DNA/RNA duplex would be readily cleaved by RNase H in the intracellular environment. After the cleavage, ChriST mRNA was fully functionalized in cells and exhibited enhanced tumor specific DC maturation.

Resveratrol Enhances mRNA and siRNA Lipid Nanoparticles Primary CLL Cell Transfection

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western populations. Therapies such as mRNA and siRNA encapsulated in lipid nanoparticles (LNPs) represent a clinically advanced platform and are utilized for a wide variety of applications. Unfortunately, transfection of RNA into CLL cells remains a formidable challenge and a bottleneck for developing targeted therapies for this disease. Therefore, we aimed to elucidate the barriers to efficient transfection of RNA-encapsulated LNPs into primary CLL cells to advance therapies in the future. To this end, we transfected primary CLL patient samples with mRNA and siRNA payloads encapsulated in an FDA-approved LNP formulation and characterized the transfection. Additionally, we tested the potential of repurposing caffeic acid, curcumin and resveratrol to enhance the transfection of nucleic acids into CLL cells. The results demonstrate that the rapid uptake of LNPs is required for successful transfection. Furthermore, we demonstrate that resveratrol enhances the delivery of both mRNA and siRNA encapsulated in LNPs into primary CLL patient samples, overcoming inter-patient heterogeneity. This study points out the important challenges to consider for efficient RNA therapeutics for CLL patients and advocates the use of resveratrol in combination with RNA lipid nanoparticles to enhance delivery into CLL cells.

Long-term storage of lipid-like nanoparticles for mRNA delivery

Lipid-like nanoparticles (LLNs) have been extensively explored for messenger RNA (mRNA) delivery in various biomedical applications. However, the long-term storage of these nanoparticles is still a challenge for their clinical translation. In this study, we investigated a series of conditions for the long-term storage of LLNs with encapsulation of mRNA. We evaluated the stability of LLNs with different concentrations of cryoprotectants (sucrose, trehalose or mannitol) under the conditions of freezing or lyophilization processes. Through in vitro and in vivo mRNA delivery studies, we identified the optimal storage condition, and found that the addition with 5% (w/v) sucrose or trehalose to LLNs could remain their mRNA delivery efficiency for at least three months in the liquid nitrogen storage condition.

Targeted lipid nanoparticles for RNA therapeutics and immunomodulation in leukocytes

Abnormalities in leukocytes' function are associated with many immune related disorders, such as cancer, autoimmunity and susceptibility to infectious diseases. Recent developments in Genome-wide-association-studies give rise to new opportunities for novel therapeutics. RNA-based modalities, that allow a selective genetic manipulation in vivo, are powerful tools for personalized medicine, enabling downregulation or expression of relevant proteins. Yet, RNA-based therapeutics requires a delivery modality to facilitate the stability, uptake and intracellular release of the RNA molecules. The use of lipid nanoparticles as a drug delivery approach improves the payloads' stability, pharmacokinetics, bio-distribution and therapeutic benefit while reducing side effects. Moreover, a wide variety of targeting moieties allow a precise and modular manipulation of gene expression, together with the ability to identify and selectively affect disease-relevant leukocytes-subsets. Altogether, RNA-based therapeutics, targeting leukocytes subsets, is believed to be one of the most promising therapeutic concepts of the near future, addressing pressing issues in cancer and inflammation heterogeneity.

Gold Nanoparticle-Mediated Photoporation Enables Delivery of Macromolecules over a Wide Range of Molecular Weights in Human CD4+ T Cells

The modification of CD4+ T cells with exogenous nucleic acids or proteins is a critical step in several research and therapeutic applications, such as HIV studies and cancer immunotherapies. However, efficient cell transfections are not always easily achieved when working with these primary hard-to-transfect cells. While the modification of T cells is typically performed by viral transduction or electroporation, their use is associated with safety issues or cytotoxicity. Vapor nanobubble (VNB) photoporation with sensitizing gold nanoparticles (AuNPs) has recently emerged as a new technology for safe and flexible cell transfections. In this work, we evaluated the potential of VNB photoporation as a novel technique for the intracellular delivery of macromolecules in primary human CD4+ T cells using fluorescent dextrans as model molecules. Our results show that VNB photoporation enables efficient delivery of fluorescent dextrans of 10 kDa in Jurkat (>60% FD10+ cells) as well as in primary human CD4+ T cells (±40% FD10+ cells), with limited cell toxicity (>70% cell viability). We also demonstrated that the technique allows the delivery of dextrans that are up to 500 kDa in Jurkat cells, suggesting its applicability for the delivery of biological macromolecules with a wide range of molecular weights. Altogether, VNB photoporation represents a promising technique for the universal delivery of macromolecules in view of engineering CD4+ T cells for use in a wide variety of research and therapeutic applications.