Lipid Nanoparticles for Organ-Specific mRNA Therapeutic Delivery

mRNA-based therapeutic strategies for cancer treatment

In the rapidly evolving landscape of medical research, the emergence of RNA-based therapeutics is paradigm shifting. It is mainly driven by the molecular adaptability and capacity to provide precision in targeting. The coronavirus disease 2019 pandemic crisis underscored the effectiveness of the mRNA therapeutic development platform and brought it to the forefront of RNA-based interventions. These RNA-based therapeutic approaches can reshape gene expression, manipulate cellular functions, and correct the aberrant molecular processes underlying various diseases. The new technologies hold the potential to engineer and deliver tailored therapeutic agents to tackle genetic disorders, cancers, and infectious diseases in a highly personalized and precisely tuned manner. The review discusses the most recent advancements in the field of mRNA therapeutics for cancer treatment, with a focus on the features of the most utilized RNA-based therapeutic interventions, current pre-clinical and clinical developments, and the remaining challenges in delivery strategies, effectiveness, and safety considerations.

RNA-based logic for selective protein expression in senescent cells

Cellular senescence is a cellular state characterized by irreversible growth arrest, resistance to apoptosis and secretion of inflammatory molecules, which is causally linked to the pathogenesis of many age-related diseases. Besides, there is accumulating evidence that selective removal of senescent cells can benefit therapies for cancer and fibrosis by modulating the inflammatory microenvironment. While the field of so-called senolytics has spawned promising small molecules and peptides for the selective removal of senescent cells, there is still no effective means to detect senescent cells in vivo, a prerequisite for understanding the role of senescence in pathophysiology and to assess the effectiveness of treatments aimed at removing senescent cells. Here, we present a strategy based on an mRNA logic circuit, that yields mRNA-dependent protein expression only when a senescence-specific miRNA signature is present. Following a validation of radiation-induced senescence induction in primary human fibroblasts, we identify miRNAs up- and downregulated in association with cellular senescence using RT-qPCR. Incorporating binding sites to these miRNAs into the 3' untranslated regions of the mRNA logic circuit, we demonstrate the senescence-specific expression of EGFP for detection of senescent cells and of a constitutively active caspase-3 for selective removal. Altogether, our results pave the way for a novel approach to execute an mRNA-based programme specifically in senescent cells aimed at their detection or selective removal.

In vivo Fate of Targeted Drug Delivery Carriers

This review aimed to systematically investigate the intracellular and subcellular fate of various types of targeting carriers. Upon entering the body via intravenous injection or other routes, a targeting carrier that can deliver therapeutic agents initiates their journey. If administered intravenously, the carrier initially faces challenges presented by the blood circulation before reaching specific tissues and interacting with cells within the tissue. At the subcellular level, the car2rier undergoes processes, such as drug release, degradation, and metabolism, through specific pathways. While studies on the fate of 13 types of carriers have been relatively conclusive, these studies are incomplete and lack a comprehensive analysis. Furthermore, there are still carriers whose fate remains unclear, underscoring the need for continuous research. This study highlights the importance of comprehending the in vivo and intracellular fate of targeting carriers and provides valuable insights into the operational mechanisms of different carriers within the body. By doing so, researchers can effectively select appropriate carriers and enhance the successful clinical translation of new formulations.

Emerging mRNA Technology for Liver Disease Therapy

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

Enhancing Cytoplasmic Expression of Exogenous mRNA through Dynamic Mechanical Stimulation

Ionizable lipid nanoparticles (LNPs) have been pivotal in combating COVID-19, and numerous preclinical and clinical studies have highlighted their potential in nucleic acid-based therapies and vaccines. However, the effectiveness of endosomal escape for the nucleic acid cargos encapsulated in LNPs is still low, leading to suboptimal treatment outcomes and side effects. Hence, improving endosomal escape is crucial for enhancing the efficacy of nucleic acid delivery using LNPs. Here, a mechanical oscillation (frequency: 65 Hz) is utilized to prompt the LNP-mediated endosomal escape. The results reveal this mechanical oscillation can induce the combination and fusion between LNPs with opposite surface charges, enhance endosomal escape of mRNA by 14%, and increase the transfection efficiency of mRNA up to 1.67 times in the current study. Additionally, cell viability remains high at 99.3% after treatment with oscillation, which is comparable to that of untreated cells. Furthermore, there is no obvious damage to other membranous organelles. Thus, this work presents a user-friendly and safe approach to enhancing endosomal escape of mRNA and boosting gene expression. As a result, our work can be potentially utilized in both research and clinical fields to facilitate LNP-based delivery by enabling more effective release of LNP-encapsulated cargos from endosomes.

RNA therapeutics in targeting G protein-coupled receptors: Recent advances and challenges

G protein-coupled receptors (GPCRs) are the major targets of existing drugs for a plethora of human diseases and dominate the pharmaceutical market. However, over 50% of the GPCRs remain undruggable. To pursue a breakthrough and overcome this situation, there is significant clinical research for developing RNA-based drugs specifically targeting GPCRs, but none has been approved so far. RNA therapeutics represent a unique and promising approach to selectively targeting previously undruggable targets, including undruggable GPCRs. However, the development of RNA therapeutics faces significant challenges in areas of RNA stability and efficient in vivo delivery. This review presents an overview of the advances in RNA therapeutics and the diverse types of nanoparticle RNA delivery systems. It also describes the potential applications of GPCR-targeted RNA drugs for various human diseases.

Modified mRNA-Mediated CCN5 Gene Transfer Ameliorates Cardiac Dysfunction and Fibrosis without Adverse Structural Remodeling

Modified mRNAs (modRNAs) are an emerging delivery method for gene therapy. The success of modRNA-based COVID-19 vaccines has demonstrated that modRNA is a safe and effective therapeutic tool. Moreover, modRNA has the potential to treat various human diseases, including cardiac dysfunction. Acute myocardial infarction (MI) is a major cardiac disorder that currently lacks curative treatment options, and MI is commonly accompanied by fibrosis and impaired cardiac function. Our group previously demonstrated that the matricellular protein CCN5 inhibits cardiac fibrosis (CF) and mitigates cardiac dysfunction. However, it remains unclear whether early intervention of CF under stress conditions is beneficial or more detrimental due to potential adverse effects such as left ventricular (LV) rupture. We hypothesized that CCN5 would alleviate the adverse effects of myocardial infarction (MI) through its anti-fibrotic properties under stress conditions. To induce the rapid expression of CCN5, ModRNA-CCN5 was synthesized and administrated directly into the myocardium in a mouse MI model. To evaluate CCN5 activity, we established two independent experimental schemes: (1) preventive intervention and (2) therapeutic intervention. Functional analyses, including echocardiography and magnetic resonance imaging (MRI), along with molecular assays, demonstrated that modRNA-mediated CCN5 gene transfer significantly attenuated cardiac fibrosis and improved cardiac function in both preventive and therapeutic models, without causing left ventricular rupture or any adverse cardiac remodeling. In conclusion, early intervention in CF by ModRNA-CCN5 gene transfer is an efficient and safe therapeutic modality for treating MI-induced heart failure.

Progress in novel delivery technologies to improve efficacy of therapeutic antibodies

Monoclonal antibody-based therapeutics have achieved remarkable success in treating a wide range of human diseases. However, conventional systemic delivery methods have limitations in insufficient target tissue permeability, high costs, repeated administrations, etc. Novel technologies have been developed to address these limitations and further enhance antibody therapy. Local antibody delivery via respiratory tract, gastrointestinal tract, eye and blood-brain barrier have shown promising results in increasing local concentrations and overcoming barriers. Nucleic acid-encoded antibodies expressed from plasmid DNA, viral vectors or mRNA delivery platforms also offer advantages over recombinant proteins such as sustained expression, rapid onset, and lower costs. This review summarizes recent advances in antibody delivery methods and highlights innovative technologies that have potential to expand therapeutic applications of antibodies.

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.

Unlocking the potential of nanocarrier-mediated mRNA delivery across diverse biomedical frontiers: A comprehensive review

Messenger RNA (mRNA) has gained marvelous attention for managing and preventing various conditions like cancer, Alzheimer's, infectious diseases, etc. Due to the quick development and success of the COVID-19 mRNA-based vaccines, mRNA has recently grown in prominence. A lot of products are in clinical trials and some are already FDA-approved. However, still improvements in line of optimizing stability and delivery, reducing immunogenicity, increasing efficiency, expanding therapeutic applications, scalability and manufacturing, and long-term safety monitoring are needed. The delivery of mRNA via a nanocarrier system gives a synergistic outcome for managing chronic and complicated conditions. The modified nanocarrier-loaded mRNA has excellent potential as a therapeutic strategy. This emerging platform covers a wide range of diseases, recently, several clinical studies are ongoing and numerous publications are coming out every year. Still, many unexplained physical, biological, and technical problems of mRNA for safer human consumption. These complications were addressed with various nanocarrier formulations. This review systematically summarizes the solved problems and applications of nanocarrier-based mRNA delivery. The modified nanocarrier mRNA meaningfully improved mRNA stability and abridged its immunogenicity issues. Furthermore, several strategies were discussed that can be an effective solution in the future for managing complicated diseases.

A Journey of Challenges and Victories: A Bibliometric Worldview of Nanomedicine since the 21st Century

Nanotechnology profoundly affects the advancement of medicine. Limitations in diagnosing and treating cancer and chronic diseases promote the growth of nanomedicine. However, there are very few analytical and descriptive studies regarding the trajectory of nanomedicine, key research powers, present research landscape, focal investigative points, and future outlooks. Herein, articles and reviews published in the Science Citation Index Expanded of Web of Science Core Collection from first January 2000 to 18th July 2023 are analyzed. Herein, a bibliometric visualization of publication trends, countries/regions, institutions, journals, research categories, themes, references, and keywords is produced and elaborated. Nanomedicine-related academic output is increasing since the COVID-19 pandemic, solidifying the uneven global distribution of research performance. While China leads in terms of publication quantity and has numerous highly productive institutions, the USA has advantages in academic impact, commercialization, and industrial value. Nanomedicine integrates with other disciplines, establishing interdisciplinary platforms, in which drug delivery and nanoparticles remain focal points. Current research focuses on integrating nanomedicine and cell ferroptosis induction in cancer immunotherapy. The keyword "burst testing" identifies promising research directions, including immunogenic cell death, chemodynamic therapy, tumor microenvironment, immunotherapy, and extracellular vesicles. The prospects, major challenges, and barriers to addressing these directions are discussed.

Current RNA strategies in treating cardiovascular diseases

Cardiovascular disease (CVD) continues to impose a significant global health burden, necessitating the exploration of innovative treatment strategies. Ribonucleic acid (RNA)-based therapeutics have emerged as a promising avenue to address the complex molecular mechanisms underlying CVD pathogenesis. We present a comprehensive review of the current state of RNA therapeutics in the context of CVD, focusing on the diverse modalities that bring about transient or permanent modifications by targeting the different stages of the molecular biology central dogma. Considering the immense potential of RNA therapeutics, we have identified common gene targets that could serve as potential interventions for prevalent Mendelian CVD caused by single gene mutations, as well as acquired CVDs developed over time due to various factors. These gene targets offer opportunities to develop RNA-based treatments tailored to specific genetic and molecular pathways, presenting a novel and precise approach to address the complex pathogenesis of both types of cardiovascular conditions. Additionally, we discuss the challenges and opportunities associated with delivery strategies to achieve targeted delivery of RNA therapeutics to the cardiovascular system. This review highlights the immense potential of RNA-based interventions as a novel and precise approach to combat CVD, paving the way for future advancements in cardiovascular therapeutics.

Restoring tolerance with antigen delivery

Strategies that modulate antigen delivery are being tested to reverse autoimmunity.

Enabling mRNA Therapeutics: Current Landscape and Challenges in Manufacturing

Recent advances and discoveries in the structure and role of mRNA as well as novel lipid-based delivery modalities have enabled the advancement of mRNA therapeutics into the clinical trial space. The manufacturing of these products is relatively simple and eliminates many of the challenges associated with cell culture production of viral delivery systems for gene and cell therapy applications, allowing rapid production of mRNA for personalized treatments, cancer therapies, protein replacement and gene editing. The success of mRNA vaccines during the COVID-19 pandemic highlighted the immense potential of this technology as a vaccination platform, but there are still particular challenges to establish mRNA as a widespread therapeutic tool. Immunostimulatory byproducts can pose a barrier for chronic treatments and different production scales may need to be considered for these applications. Moreover, long-term storage of mRNA products is notoriously difficult. This review provides a detailed overview of the manufacturing steps for mRNA therapeutics, including sequence design, DNA template preparation, mRNA production and formulation, while identifying the challenges remaining in the dose requirements, long-term storage and immunotolerance of the product.

Amending the injured heart by in vivo reprogramming

Ischemic heart injury causes death of cardiomyocyte (CM), formation of a fibrotic scar, and often adverse cardiac remodeling, resulting in chronic heart failure. Therapeutic interventions have lowered myocardial damage and improved heart function, but pharmacological treatment of heart failure has only shown limited progress in recent years. Over the past two decades, different approaches have been pursued to regenerate the heart, by transplantation of newly generated CMs derived from pluripotent stem cells, generation of new CMs by reprogramming of cardiac fibroblasts, or by activating proliferation of preexisting CMs. Here, we summarize recent progress in the development of strategies for in situ generation of new CMs, review recent advances in understanding the underlying mechanisms, and discuss the challenges and future directions of the field.

The Safety and Effectiveness of mRNA Vaccines Against SARS-CoV-2

The coronavirus disease 2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in numerous deaths worldwide, along with devastating economic disruptions, and has posed unprecedented challenges to healthcare systems around the world. In the wake of COVID-19's emergence in 2019, a variety of vaccine technologies were formulated and developed, including those that drew from the technology employed in messenger RNA (mRNA) vaccines, designed to curb the disease's transmission and manage the pandemic. mRNA vaccine has several advantages over traditional ones, and hence its development has received considerable attention recently. Researchers believe the mRNA vaccine technology will emerge as the leading technology because it is potent, inexpensive, rapidly developed, and safe. This article provides an overview of mRNA vaccines with a special focus on the efficacy and safety of the Moderna and Pfizer-BioNTech mRNA vaccines against the different variants of COVID-19 and compare them with the Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines. The clinical data reviewed in this article demonstrate that the currently authorized Moderna and Pfizer-BioNTech mRNA vaccines are highly safe and potent against different variants of COVID-19, especially in comparison with Oxford-AstraZeneca (viral vector) and Sinopharm (inactivated virus) vaccines.

Progress on RNA-based therapeutics for genetic diseases

RNA therapeutics inhibit the expression of specific proteins/RNAs by targeting complementary sequences of corresponding genes or encode proteins for the synthesis desired genes to treat genetic diseases. RNA-based therapeutics are categorized as oligonucleotide drugs (antisense oligonucleotides, small interfering RNA, RNA aptamers), and mRNA drugs. The antisense oligonucleotides and small interfering RNA for treatment of genetic diseases have been approved by the FDA in the United States, while RNA aptamers and mRNA drugs are still in clinical trials. Chemical modifications can be applied to RNA drugs, such as pseudouridine modification of mRNA, to reduce immunogenicity and improve the efficacy. The secure and effective delivery systems such as lipid-based nanoparticles, extracellular vesicles, and virus-like particles are under development to address stability, specificity, and safety issues of RNA drugs. This article provides an overview of the specific molecular mechanisms of eleven RNA drugs currently used for treating genetic diseases, and discusses the research progress of chemical modifications and delivery systems of RNA drugs.

Recent Advances in Messenger Ribonucleic Acid (mRNA) Vaccines and Their Delivery Systems: A Review

Messenger ribonucleic acid (mRNA) was found as the intermediary that transfers genetic information from DNA to ribosomes for protein synthesis in 1961. The emergency use authorization of the two covid-19 mRNA vaccines, BNT162b2 and mRNA-1273, is a significant achievement in the history of vaccine development. Because they are generated in a cell-free environment using the in vitro transcription (IVT) process, mRNA vaccines are risk-free. Moreover, chemical modifications to the mRNA molecule, such as cap structures and changed nucleosides, have proved critical in overcoming immunogenicity concerns, achieving sustained stability, and achieving effective, accurate protein production in vivo. Several vaccine delivery strategies (including protamine, lipid nanoparticles (LNPs), polymers, nanoemulsions, and cell-based administration) were also optimized to load and transport RNA into the cytosol. LNPs, which are composed of a cationic or a pH-dependent ionizable lipid layer, a polyethylene glycol (PEG) component, phospholipids, and cholesterol, are the most advanced systems for delivering mRNA vaccines. Moreover, modifications of the four components that make up the LNPs showed to increase vaccine effectiveness and reduce side effects. Furthermore, the introduction of biodegradable lipids improved LNP biocompatibility. Furthermore, mRNA-based therapies are expected to be effective treatments for a variety of refractory conditions, including infectious diseases, metabolic genetic diseases, cancer, cardiovascular and cerebrovascular diseases. Therefore, the present review aims to provide the scientific community with up-to-date information on mRNA vaccines and their delivery systems.

Bioinspired Lipid Nanocarriers for RNA Delivery

RNA therapy is a disruptive technology comprising a rapidly expanding category of drugs. Further translation of RNA therapies to the clinic will improve the treatment of many diseases and help enable personalized medicine. However, in vivo delivery of RNA remains challenging due to the lack of appropriate delivery tools. Current state-of-the-art carriers such as ionizable lipid nanoparticles still face significant challenges, including frequent localization to clearance-associated organs and limited (1-2%) endosomal escape. Thus, delivery vehicles must be improved to further unlock the full potential of RNA therapeutics. An emerging strategy is to modify existing or new lipid nanocarriers by incorporating bioinspired design principles. This method generally aims to improve tissue targeting, cellular uptake, and endosomal escape, addressing some of the critical issues facing the field. In this review, we introduce the different strategies for creating bioinspired lipid-based RNA carriers and discuss the potential implications of each strategy based on reported findings. These strategies include incorporating naturally derived lipids into existing nanocarriers and mimicking bioderived molecules, viruses, and exosomes. We evaluate each strategy based on the critical factors required for delivery vehicles to succeed. Finally, we point to areas of research that should be furthered to enable the more successful rational design of lipid nanocarriers for RNA delivery.

Genome editing in cancer: Challenges and potential opportunities

Ever since its mechanism was discovered back in 2012, the CRISPR/Cas9 system have revolutionized the field of genome editing. While at first it was seen as a therapeutic tool mostly relevant for curing genetic diseases, it has been recently shown to also hold the potential to become a clinically relevant therapy for cancer. However, there are multiple challenges that must be addressed prior to clinical testing. Predominantly, the safety of the system when used for in-vivo therapies, including off-target activity and the effects of the double strand break induction on genomic stability. Here, we will focus on the inherent challenges in the CRISPR/Cas9 system and discuss various opportunities to overcoming these challenges.

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In recent years, several works have shown that knocking down key genes by CRISPR/Cas9 based could potentially be a new type of cancer therapy.

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This has been made possible due to advances in the fields of In-vivo delivery, such as lentiviral vectors and lipid nanoparticles.

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Limiting CRISPR/Cas9 activity to the tumor and minimizing off-target activity are challenges that must be overcome before proceeding to the clinic.

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We review approaches arising from multiple disciplines that could overcome these challenges.

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The combination of these multi-disciplinary approaches should be able to overcome the different challenges and open the way to the clinic.

Ionizable drug delivery systems for efficient and selective gene therapy

Gene therapy has shown great potential to treat various diseases by repairing the abnormal gene function. However, a great challenge in bringing the nucleic acid formulations to the market is the safe and effective delivery to the specific tissues and cells. To be excited, the development of ionizable drug delivery systems (IDDSs) has promoted a great breakthrough as evidenced by the approval of the BNT162b2 vaccine for prevention of coronavirus disease 2019 (COVID-19) in 2021. Compared with conventional cationic gene vectors, IDDSs can decrease the toxicity of carriers to cell membranes, and increase cellular uptake and endosomal escape of nucleic acids by their unique pH-responsive structures. Despite the progress, there remain necessary requirements for designing more efficient IDDSs for precise gene therapy. Herein, we systematically classify the IDDSs and summarize the characteristics and advantages of IDDSs in order to explore the underlying design mechanisms. The delivery mechanisms and therapeutic applications of IDDSs are comprehensively reviewed for the delivery of pDNA and four kinds of RNA. In particular, organ selecting considerations and high-throughput screening are highlighted to explore efficiently multifunctional ionizable nanomaterials with superior gene delivery capacity. We anticipate providing references for researchers to rationally design more efficient and accurate targeted gene delivery systems in the future, and indicate ideas for developing next generation gene vectors.

Lipid nanoparticles technology in vaccines: Shaping the future of prophylactic medicine

Throughout decades, the intrinsic power of the immune system to fight pathogens has inspired researchers to develop techniques that enable the prevention or treatment of infections via boosting the immune response against the target pathogens, which has led to the evolution of vaccines. The recruitment of Lipid nanoparticles (LNPs) as either vaccine delivery platforms or immunogenic modalities has witnessed a breakthrough recently, which has been crowned with the development of effective LNPs-based vaccines against COVID-19. In the current article, we discuss some principles of such a technology, with a special focus on the technical aspects from a translational perspective. Representative examples of LNPs-based vaccines against cancer, COVID-19, as well as other infectious diseases, autoimmune diseases, and allergies are highlighted, considering the challenges and promises. Lastly, the key features that can improve the clinical translation of this area of endeavor are inspired.

miRNAs: The Road from Bench to Bedside

miRNAs are small noncoding RNAs that control gene expression at the posttranscriptional level. It has been recognised that miRNA dysregulation reflects the state and function of cells and tissues, contributing to their dysfunction. The identification of hundreds of extracellular miRNAs in biological fluids has underscored their potential in the field of biomarker research. In addition, the therapeutic potential of miRNAs is receiving increasing attention in numerous conditions. On the other hand, many operative problems including stability, delivery systems, and bioavailability, still need to be solved. In this dynamic field, biopharmaceutical companies are increasingly engaged, and ongoing clinical trials point to anti-miR and miR-mimic molecules as an innovative class of molecules for upcoming therapeutic applications. This article aims to provide a comprehensive overview of current knowledge on several pending issues and new opportunities offered by miRNAs in the treatment of diseases and as early diagnostic tools in next-generation medicine.

Oligonucleotide Therapeutics for Age-Related Musculoskeletal Disorders: Successes and Challenges

Age-related disorders of the musculoskeletal system including sarcopenia, osteoporosis and arthritis represent some of the most common chronic conditions worldwide, for which there remains a great clinical need to develop safer and more efficacious pharmacological treatments. Collectively, these conditions involve multiple tissues, including skeletal muscle, bone, articular cartilage and the synovium within the joint lining. In this review, we discuss the potential for oligonucleotide therapies to combat the unmet clinical need in musculoskeletal disorders by evaluating the successes of oligonucleotides to modify candidate pathological gene targets and cellular processes in relevant tissues and cells of the musculoskeletal system. Further, we discuss the challenges that remain for the clinical development of oligonucleotides therapies for musculoskeletal disorders and evaluate some of the current approaches to overcome these.

Acidification-Induced Structure Evolution of Lipid Nanoparticles Correlates with Their In Vitro Gene Transfections

The rational design of lipid nanoparticles (LNPs) for enhanced gene delivery remains challenging because of incomplete knowledge of their formulation-structure relationship that impacts their intracellular behavior and consequent function. Small-angle neutron scattering has been used in this work to investigate the structure of LNPs encapsulating plasmid DNA upon their acidification (from pH 7.4 to 4.0), as would be encountered during endocytosis. The results revealed the acidification-induced structure evolution (AISE) of the LNPs on different dimension scales, involving protonation of the ionizable lipid, volume expansion and redistribution of aqueous and lipid components. A similarity analysis using an LNP's structural feature space showed a strong positive correlation between function (measured by intracellular luciferase expression) and the extent of AISE, which was further enhanced by the fraction of unsaturated helper lipid. Our findings reveal molecular and nanoscale changes occurring during AISE that underpin the LNPs' formulation-nanostructure-function relationship, aiding the rational design of application-directed gene delivery vehicles.

The development of highly dense highly protected surfactant ionizable lipid RNA loaded nanoparticles

The long quest for efficient drug administration has been looking for a universal carrier that can precisely transport traditional drugs, new genomic and proteic therapeutic agents. Today, researchers have found conditions to overcome the two main drug delivery dilemmas. On the one side, the versatility of the vehicle to efficiently load, protect and transport the drug and then release it at the target place. On the other hand, the questions related to the degree of PEGylation which are needed to avoid nanoparticle (NP) aggregation and opsonization while preventing cellular uptake. The development of different kinds of lipidic drug delivery vehicles and particles has resulted in the development of ionizable lipid nanoparticles (iLNPs), which can overcome most of the typical drug delivery problems. Proof of their success is the late approval and massive administration as the prophylactic vaccine for SARS-CoV-2. These ILNPs are built by electrostatic aggregation of surfactants, the therapeutic agent, and lipids that self-segregate from an aqueous solution, forming nanoparticles stabilized with lipid polymers, such as PEG. These vehicles overcome previous limitations such as low loading and high toxicity, likely thanks to low charge at the working pH and reduced size, and their entry into the cells via endocytosis rather than membrane perforation or fusion, always associated with higher toxicity. We herein revise their primary features, synthetic methods to prepare and characterize them, pharmacokinetic (administration, distribution, metabolization and excretion) aspects, and biodistribution and fate. Owing to their advantages, iLNPs are potential drug delivery systems to improve the management of various diseases and widely available for clinical use.

Advancing mRNA technologies for therapies and vaccines: An African context

Synthetic mRNA technologies represent a versatile platform that can be used to develop advanced drug products. The remarkable speed with which vaccine development programs designed and manufactured safe and effective COVID-19 vaccines has rekindled interest in mRNA technology, particularly for future pandemic preparedness. Although recent R&D has focused largely on advancing mRNA vaccines and large-scale manufacturing capabilities, the technology has been used to develop various immunotherapies, gene editing strategies, and protein replacement therapies. Within the mRNA technologies toolbox lie several platforms, design principles, and components that can be adapted to modulate immunogenicity, stability, in situ expression, and delivery. For example, incorporating modified nucleotides into conventional mRNA transcripts can reduce innate immune responses and improve in situ translation. Alternatively, self-amplifying RNA may enhance vaccine-mediated immunity by increasing antigen expression. This review will highlight recent advances in the field of synthetic mRNA therapies and vaccines, and discuss the ongoing global efforts aimed at reducing vaccine inequity by establishing mRNA manufacturing capacity within Africa and other low- and middle-income countries.

Genetically modified immunomodulatory cell-based biomaterials in tissue regeneration and engineering

To date, the wide application of cell-based biomaterials in tissue engineering and regeneration is remarkably hampered by immune rejection. Reducing the immunogenicity of cell-based biomaterials has become the latest direction in biomaterial research. Recently, genetically modified cell-based biomaterials with immunomodulatory genes have become a feasible solution to the immunogenicity problem. In this review, recent advances and future challenges of genetically modified immunomodulatory cell-based biomaterials are elaborated, including fabrication approaches, mechanisms of common immunomodulatory genes, application and, more importantly, current preclinical and clinical advances. The fabrication approaches can be categorized into commonly used (e.g., virus transfection) and newly developed approaches. The immunomodulatory mechanisms of representative genes involve complicated cell signaling pathways and metabolic activities. Wide application in curing multiple end-term diseases and replacing lifelong immunosuppressive therapy in multiple cell and organ transplantation models is demonstrated. Most significantly, practices of genetically modified organ transplantation have been conducted on brain-dead human decedent and even on living patients after a series of experiments on nonhuman primates. Nevertheless, uncertain biosecurity, nonspecific effects and overlooked personalization of current genetically modified immunomodulatory cell-based biomaterials are shortcomings that remain to be overcome.

Regulatory guidelines and preclinical tools to study the biodistribution of RNA therapeutics

The success of the messenger RNA-based COVID-19 vaccines of Moderna and Pfizer/BioNTech marks the beginning of a new chapter in modern medicine. However, the rapid rise of mRNA therapeutics has resulted in a regulatory framework that is somewhat lagging. The current guidelines either do not apply, do not mention RNA therapeutics, or do not have widely accepted definitions. This review describes the guidelines for preclinical biodistribution studies of mRNA/siRNA therapeutics and highlights the relevant differences for mRNA vaccines. We also discuss the role of in vivo RNA imaging techniques and other assays to fulfill and/or complement the regulatory requirements. Specifically, quantitative whole-body autoradiography, microautoradiography, mass spectrometry-based assays, hybridization techniques (FISH, bDNA), PCR-based methods, in vivo fluorescence imaging, and in vivo bioluminescence imaging, are discussed. We conclude that this new and rapidly evolving class of medicines demands a multi-layered approach to fully understand its biodistribution and in vivo characteristics.

Next generation self-replicating RNA vectors for vaccines and immunotherapies

RNA technology has recently come to the forefront of innovative medicines and is being explored for a wide range of therapies, including prophylactic and therapeutic vaccines, biotherapeutic protein expression and gene therapy. In addition to conventional mRNA platforms now approved for prophylactic SARS-CoV2 vaccines, synthetic self-replicating RNA vaccines are currently being evaluated in the clinic for infectious disease and oncology. The prototypical srRNA vectors in clinical development are derived from alphaviruses, specifically Venezuelan Equine Encephalitis Virus (VEEV). While non-VEEV alphaviral strains have been explored as single cycle viral particles, their use as synthetic vectors largely remains under-utilized in clinical applications. Here we describe the potential commonalities and differences in synthetic alphaviral srRNA vectors in host cell interactions, immunogenicity, cellular delivery, and cargo expression. Thus, unlike the current thinking that VEEV-based srRNA is a one-size-fits-all platform, we argue that a new drug development approach leveraging panels of customizable, synthetic srRNA vectors will be required for clinical success.

Lipid-Based Nanocarriers in Renal RNA Therapy

Kidney disease is a multifactorial problem, with a growing prevalence and an increasing global burden. With the latest worldwide data suggesting that chronic kidney disease (CKD) is the 12th leading cause of death, it is no surprise that CKD remains a public health problem that requires urgent attention. Multiple factors contribute to kidney disease, each with its own pathophysiology and pathogenesis. Furthermore, microRNAs (miRNAs) have been linked to several types of kidney diseases. As dysregulation of miRNAs is often seen in some diseases, there is potential in the exploitation of this for therapeutic applications. In addition, uptake of interference RNA has been shown to be rapid in kidneys making them a good candidate for RNA therapy. The latest advancements in RNA therapy and lipid-based nanocarriers have enhanced the effectiveness and efficiency of RNA-related drugs, thereby making RNA therapy a viable treatment option for renal disease. This is especially useful for renal diseases, for which a suitable treatment is not yet available. Moreover, the high adaptability of RNA therapy combined with the low risk of lipid-based nanocarriers make for an attractive treatment choice. Currently, there are only a small number of RNA-based drugs related to renal parenchymal disease, most of which are in different stages of clinical trials. We propose the use of miRNAs or short interfering RNAs coupled with a lipid-based nanocarrier as a delivery vehicle for managing renal disease.

Virus-Like Particles: Revolutionary Platforms for Developing Vaccines Against Emerging Infectious Diseases

Virus-like particles (VLPs) are nanostructures that possess diverse applications in therapeutics, immunization, and diagnostics. With the recent advancements in biomedical engineering technologies, commercially available VLP-based vaccines are being extensively used to combat infectious diseases, whereas many more are in different stages of development in clinical studies. Because of their desired characteristics in terms of efficacy, safety, and diversity, VLP-based approaches might become more recurrent in the years to come. However, some production and fabrication challenges must be addressed before VLP-based approaches can be widely used in therapeutics. This review offers insight into the recent VLP-based vaccines development, with an emphasis on their characteristics, expression systems, and potential applicability as ideal candidates to combat emerging virulent pathogens. Finally, the potential of VLP-based vaccine as viable and efficient immunizing agents to induce immunity against virulent infectious agents, including, SARS-CoV-2 and protein nanoparticle-based vaccines has been elaborated. Thus, VLP vaccines may serve as an effective alternative to conventional vaccine strategies in combating emerging infectious diseases.