The hydrophobic tail of a pH-sensitive cationic lipid influences siRNA transfection activity and toxicity in human NK cell lines

Enhancing Cytoplasmic Expression of Exogenous mRNA Through Dynamic Mechanical Stimulation

Ionizable lipid nanoparticles (LNPs) are 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, and increase the transfection efficiency of mRNA. 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 mitochondrial membrane potential and Golgi apparatus integrity. Thus, this work presents a user-friendly and safe approach to enhancing endosomal escape of mRNA and boosting gene expression. As a result, this 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.

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, and increase the transfection efficiency of mRNA. 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 mitochondrial membrane potential and Golgi apparatus integrity. 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.

Non-viral approaches in CAR-NK cell engineering: connecting natural killer cell biology and gene delivery

Natural Killer (NK) cells are exciting candidates for cancer immunotherapy with potent innate cytotoxicity and distinct advantages over T cells for Chimeric Antigen Receptor (CAR) therapy. Concerns regarding the safety, cost, and scalability of viral vectors has ignited research into non-viral alternatives for gene delivery. This review comprehensively analyses recent advancements and challenges with non-viral genetic modification of NK cells for allogeneic CAR-NK therapies. Non-viral alternatives including electroporation and multifunctional nanoparticles are interrogated with respect to CAR expression and translational responses. Crucially, the link between NK cell biology and design of drug delivery technologies are made, which is essential for development of future non-viral approaches. This review provides valuable insights into the current state of non-viral CAR-NK cell engineering, aimed at realising the full potential of NK cell-based immunotherapies.

Current landscape of mRNA technologies and delivery systems for new modality therapeutics

Realizing the immense clinical potential of mRNA-based drugs will require continued development of methods to safely deliver the bioactive agents with high efficiency and without triggering side effects. In this regard, lipid nanoparticles have been successfully utilized to improve mRNA delivery and protect the cargo from extracellular degradation. Encapsulation in lipid nanoparticles was an essential factor in the successful clinical application of mRNA vaccines, which conclusively demonstrated the technology's potential to yield approved medicines. In this review, we begin by describing current advances in mRNA modifications, design of novel lipids and development of lipid nanoparticle components for mRNA-based drugs. Then, we summarize key points pertaining to preclinical and clinical development of mRNA therapeutics. Finally, we cover topics related to targeted delivery systems, including endosomal escape and targeting of immune cells, tumors and organs for use with mRNA vaccines and new treatment modalities for human diseases.

Dual Effect by Chemical Electron Transfer Enhanced siRNA Lipid Nanoparticles: Reactive Oxygen Species-Triggered Tumor Cell Killing Aggravated by Nrf2 Gene Silencing

Insufficient endosomal escape presents a major hurdle for successful nucleic acid therapy. Here, for the first time, a chemical electron transfer (CET) system was integrated into small interfering RNA (siRNA) lipid nanoparticles (LNPs). The CET acceptor can be chemically excited using the generated energy between the donor and hydrogen peroxide, which triggers the generation of reactive oxygen species (ROS), promoting endosomal lipid membrane destabilization. Tetra-oleoyl tri-lysino succinoyl tetraethylene pentamine was included as an ionizable lipopeptide with a U-shaped topology for effective siRNA encapsulation and pH-induced endosomal escape. LNPs loaded with siRNA and CET components demonstrated a more efficient endosomal escape, as evidenced by a galectin-8-mRuby reporter; ROS significantly augmented galectin-8 recruitment by at least threefold compared with the control groups, with a p value of 0.03. Moreover, CET-enhanced LNPs achieved a 24% improvement in apoptosis level by knocking down the tumor-protective gene nuclear factor erythroid 2-related factor 2, boosting the CET-mediated ROS cell killing.

The impact of, and expectations for, lipid nanoparticle technology: From cellular targeting to organelle targeting

The success of mRNA vaccines against COVID-19 has enhanced the potential of lipid nanoparticles (LNPs) as a system for the delivery of mRNA. In this review, we describe our progress using a lipid library to engineer ionizable lipids and promote LNP technology from the viewpoints of safety, controlled biodistribution, and mRNA vaccines. These advancements in LNP technology are applied to cancer immunology, and a potential nano-DDS is constructed to evaluate immune status that is associated with a cancer-immunity cycle that includes the sub-cycles in tumor microenvironments. We also discuss the importance of the delivery of antigens and adjuvants in enhancing the cancer-immunity cycle. Recent progress in NK cell targeting in cancer immunotherapy is also introduced. Finally, the impact of next-generation DDS technology is explained using the MITO-Porter membrane fusion-based delivery system for the organelle targeting of the mitochondria. We introduce a successful example of the MITO-Porter used in a cell therapeutic strategy to treat cardiomyopathy.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

Lipid Nanoparticle-Based Delivery System-A Competing Place for mRNA Vaccines

mRNA, as one of the foci of biomedical research in the past decade, has become a candidate vaccine solution for various infectious diseases and tumors and for regenerative medicine and immunotherapy due to its high efficiency, safety, and effectiveness. A stable and effective delivery system is needed to protect mRNAs from nuclease degradation while also enhancing immunogenicity. The success of mRNA lipid nanoparticles in treating COVID-19, to a certain extent, marks a milestone for mRNA vaccines and also promotes further research on mRNA delivery systems. Here, we explore mRNA vaccine delivery systems, especially lipid nanoparticles (LNPs), considering the current research status, prospects, and challenges of lipid nanoparticles, and explore other mRNA delivery systems.

Lipid Nanoparticles Optimized for Targeting and Release of Nucleic Acid

Lipid nanoparticles (LNPs) are currently the most promising clinical nucleic acids drug delivery vehicles. LNPs prevent the degradation of cargo nucleic acids during blood circulation. Upon entry into the cell, specific components of the lipid nanoparticles can promote the endosomal escape of nucleic acids. These are the basic properties of lipid nanoparticles as nucleic acid carriers. As LNPs exhibit hepatic aggregation characteristics, enhancing targeting out of the liver is a crucial way to improve LNPs administrated in vivo. Meanwhile, endosomal escape of nucleic acids loaded in LNPs is often considered inadequate, and therefore, much effort is devoted to enhancing the intracellular release efficiency of nucleic acids. Here, different strategies to efficiently deliver nucleic acid delivery from LNPs are concluded and their mechanisms are investigated. In addition, based on the information on LNPs that are in clinical trials or have completed clinical trials, the issues that are necessary to be approached in the clinical translation of LNPs are discussed, which it is hoped will shed light on the development of LNP nucleic acid drugs.

Epigenetic regulation of temozolomide resistance in human cancers with an emphasis on brain tumors: Function of non-coding RNAs

Brain tumors, which are highly malignant, pose a significant threat to health and often result in substantial rates of mortality and morbidity worldwide. The brain cancer therapy has been challenging due to obstacles such as the BBB, which hinders effective delivery of therapeutic agents. Additionally, the emergence of drug resistance further complicates the management of brain tumors. TMZ is utilized in brain cancer removal, but resistance is a drawback. ncRNAs are implicated in various diseases, and their involvement in the cancer is particularly noteworthy. The focus of the current manuscript is to explore the involvement of ncRNAs in controlling drug resistance, specifically in the context of resistance to the chemotherapy drug TMZ. The review emphasizes the function of ncRNAs, particularly miRNAs, in modulating the growth and invasion of brain tumors, which significantly influences their response to TMZ treatment. Through their interactions with various molecular pathways, miRNAs are modulators of TMZ response. Similarly, lncRNAs also associate with molecular pathways and miRNAs, affecting the efficacy of TMZ chemotherapy. Given their functional properties, lncRNAs can either induce or suppress TMZ resistance in brain tumors. Furthermore, circRNAs, which are cancer controllers, regulate miRNAs by acting as sponges, thereby impacting the response to TMZ chemotherapy. The review explores the correlation between ncRNAs and TMZ chemotherapy, shedding light on the underlying molecular pathways involved in this process.

Remodeling the tumor immune microenvironment via siRNA therapy for precision cancer treatment

How to effectively transform the pro-oncogenic tumor microenvironments (TME) surrounding a tumor into an anti-tumoral never fails to attract people to study. Small interfering RNA (siRNA) is considered one of the most noteworthy research directions that can regulate gene expression following a process known as RNA interference (RNAi). The research about siRNA delivery targeting tumor cells and TME has been on the rise in recent years. Using siRNA drugs to silence critical proteins in TME was one of the most efficient solutions. However, the manufacture of a siRNA delivery system faces three major obstacles, i.e., appropriate cargo protection, accurately targeted delivery, and site-specific cargo release. In the following review, we summarized the pharmacological actions of siRNA drugs in remolding TME. In addition, the delivery strategies of siRNA drugs and combination therapy with siRNA drugs to remodel TME are thoroughly discussed. In the meanwhile, the most recent advancements in the development of all clinically investigated and commercialized siRNA delivery technologies are also presented. Ultimately, we propose that nanoparticle drug delivery siRNA may be the future research focus of oncogene therapy. This summary offers a thorough analysis and roadmap for general readers working in the field.

Research progress in leveraging biomaterials for enhancing NK cell immunotherapy

NK cell immunotherapy is a promising antitumor therapeutic modality after the development of T cell immunotherapy. Structural modification of NK cells with biomaterials may provide a precise, efficient, and low-cost strategy to enhance NK cell immunotherapy. The biomaterial modification of NK cells can be divided into two strategies: surface engineering with biomaterials and intracellular modification. The surface engineering strategies include hydrophobic interaction of lipids, receptor-ligand interaction between membrane proteins, covalent binding to amino acid residues, click reaction and electrostatic interaction. The intracellular modification strategies are based on manipulation by nanotechnology using membranous materials from various sources of NK cells (such as exosome, vesicle and cytomembranes). Finally, the biomaterials-based strategies regulate the recruitment, recognition and cytotoxicity of NK cells in the solid tumor site in situ to boost the activity of NK cells in the tumor. This article reviews the recent research progress in enhancing NK cell therapy based on biomaterial modification, to provide a reference for further researches on engineering NK cell therapy with biomaterials.

A cationic lipid with advanced membrane fusion performance for pDNA and mRNA delivery

The success of mRNA vaccines for COVID-19 prevention raised global awareness of the importance of nucleic acid drugs. The approved systems for nucleic acid delivery were mainly formulations of different lipids, yielding lipid nanoparticles (LNPs) with complex internal structures. Due to the multiple components, the relationship between the structure of each component and the overall biological activity of LNPs is hard to study. However, ionizable lipids have been extensively explored. In contrast to former studies on the optimization of hydrophilic parts in single-component self-assemblies, we report in this study on structural alterations of the hydrophobic segment. We synthesize a library of amphiphilic cationic lipids by varying the lengths (C = 8-18), numbers (N = 2, 4), and unsaturation degrees (Ω = 0, 1) of hydrophobic tails. Notably, all self-assemblies with nucleic acid have significant differences in particle size, stability in serum, membrane fusion, and fluidity. Moreover, the novel mRNA/pDNA formulations are characterized by overall low cytotoxicity, efficient compaction, protection, and release of nucleic acids. We find that the length of hydrophobic tails dominates the formation and stability of the assembly. And at a certain length, the unsaturated hydrophobic tails enhance the membrane fusion and fluidity of assemblies and thus significantly affect the transgene expression, followed by the number of hydrophobic tails.

Delivering mRNA to a human NK cell line, NK-92 cells, by lipid nanoparticles

In cancer immunotherapy, therapeutic methods targeting NK are highly expected. NK cell-based therapy using NK-92, a human NK cell line, has been clinically evaluated. Delivering mRNA into NK-92 cells is a potent strategy for enhancing its functions. However, the use of lipid nanoparticles (LNP) for this purpose has not yet been evaluated. We previously developed a LNP that was composed of CL1H6 (CL1H6-LNP) for the efficient delivery of siRNA to NK-92 cells, and the use of this material for delivering mRNA to NK-92 cells is reported in this study. Compared with a DLin-MC3-DMA based LNP, used as a benchmark, the CL1H6-LNP caused a high mRNA expression intensity and a cell transfection efficiency of 100%. The efficient mRNA delivery by this CL1H6-LNP is attributed to the high affinity for NK-92 cells and the intense, rapid fusion with the endosomal membrane. It therefore appears that the CL1H6-LNP could be a useful non-viral vector for modifying the NK-92 functions by mRNA. Our findings also provide some insights into the design and development of LNPs for delivering mRNA to NK-92 and NK cells.

Structure and Function of Cationic and Ionizable Lipids for Nucleic Acid Delivery

Hereditary genetic diseases, cancer, and infectious diseases are affecting global health and become major health issues, but the treatment development remains challenging. Gene therapies using DNA plasmid, RNAi, miRNA, mRNA, and gene editing hold great promise. Lipid nanoparticle (LNP) delivery technology has been a revolutionary development, which has been granted for clinical applications, including mRNA vaccines against SARS-CoV-2 infections. Due to the success of LNP systems, understanding the structure, formulation, and function relationship of the lipid components in LNP systems is crucial for design more effective LNP. Here, we highlight the key considerations for developing an LNP system. The evolution of structure and function of lipids as well as their LNP formulation from the early-stage simple formulations to multi-components LNP and multifunctional ionizable lipids have been discussed. The flexibility and platform nature of LNP enable efficient intracellular delivery of a variety of therapeutic nucleic acids and provide many novel treatment options for the diseases that are previously untreatable.

Extrahepatic targeting of lipid nanoparticles in vivo with intracellular targeting for future nanomedicines

A new era of nanomedicines that involve nucleic acids/gene therapy has been opened after two decades in 21^st century and new types of more efficient drug delivery systems (DDS) are highly expected and will include extrahepatic delivery. In this review, we summarize the possibility and expectations for the extrahepatic delivery of small interfering RNA/messenger RNA/plasmid DNA/genome editing to the spleen, lung, tumor, lymph nodes as well as the liver based on our studies as well as reported information. Passive targeting and active targeting are discussed in in vivo delivery and the importance of controlled intracellular trafficking for successful therapeutic results are also discussed. In addition, mitochondrial delivery as a novel strategy for nucleic acids/gene therapy is introduced to expand the therapeutic dimension of nucleic acids/gene therapy in the liver as well as the heart, kidney and brain.

Innovative cancer nanomedicine based on immunology, gene editing, intracellular trafficking control

The recent rapid progress in the area of drug delivery systems (DDS) has opened a new era in medicine with a strong linkage to understanding the molecular mechanisms associated with cancer survival. In this review, we summarize new cancer strategies that have recently been developed based on our DDS technology. Cancer immunotherapy will be improved based on the concept of the cancer immunity cycle, which focuses on dynamic interactions between various types of cancer and immune cells in our body. The new technology of genome editing will also be discussed with reference to how these new DDS technologies can be used to introduce therapeutic cargoes into our body. Lastly, a new organelle, mitochondria will be the focus of creating a new cancer treatment strategy by a MITO-Porter which can deliver macromolecules directly to mitochondria of cancer cells via a membrane fusion approach and the impact of controlled intracellular trafficking will be discussed.

Nanotechnology for Enhanced Cytoplasmic and Organelle Delivery of Bioactive Molecules to Immune Cells

Immune cells stand as a critical component of the immune system to maintain the internal environment homeostasis. The dysfunction of immune cells can result in various life-threatening diseases, including refractory infection, diabetes, cardiovascular disease, and cancer. Therefore, strategies to standardize or even enhance the function of immune cells are critical. Recently, nanotechnology has been highly researched and extensively applied for enhancing the cytoplasmic delivery of bioactive molecules to immune cells, providing efficient approaches to correct in vivo and in vitro dysfunction of immune cells. This review focuses on the technologies and challenges involved in improving endo-lysosomal escape, cytoplasmic release and organelle targeted delivery of different bioactive molecules in immune cells. Furthermore, it will elaborate on the broader vision of applying nanotechnology for treating immune cell-related diseases and constructing immune therapies and cytopharmaceuticals as potential treatments for diseases.

Strategies for fighting pandemic virus infections: Integration of virology and drug delivery

Respiratory viruses have sometimes resulted in worldwide pandemics, with the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) being major participants. Long-term efforts have made it possible to control the influenza virus, but seasonal influenza continues to take many lives each year, and a pandemic influenza virus sometimes emerges. Although vaccines for coronavirus disease 2019 (COVID-19) have been developed, we are not yet able to coexist with the SARS-CoV-2. To overcome such viruses, it is necessary to obtain knowledge about international surveillance systems, virology, ecology and to determine that immune responses are effective. The information must then be transferred to drugs. Delivery systems would be expected to contribute to the rational development of drugs. In this review, virologist and drug delivery system (DDS) researchers discuss drug delivery strategies, especially the use of lipid-based nanocarriers, for fighting to respiratory virus infections.

Structure-activity relationships of pH-responsive and ionizable lipids for gene delivery

Ionizable lipids are the leading vectors for gene therapy. Understanding the effects of molecular structure on efficient gene delivery is one of the most important challenges for maximizing the utility of such lipid vectors. We synthesized an array of pH-responsive and ionizable lipids to investigate the relationship between lipid structure and activity. The optimized lipid (EDM) has double tertiary amines in the headgroup and an ester linker. EDM exhibited efficient DNA and siRNA delivery to, and gene silencing of, A549 cells. EDM has a pK_a value of 6.67, which enabled it to quickly escape from the endosome after entering the cell; the ester linkages rapidly degraded and enabled gene release into the cytoplasm. EDM also delivered IGF-1R siRNA to inhibit tumor growth and induce cancer cell apoptosis by efficient inhibition of IGF-1R expression in mice. Our study on the structure-activity relationships of ionizable lipids will facilitate clinical applications.

Transmission Electron Microscopy as a Powerful Tool to Investigate the Interaction of Nanoparticles with Subcellular Structures

Nanomedical research necessarily involves the study of the interactions between nanoparticulates and the biological environment. Transmission electron microscopy has proven to be a powerful tool in providing information about nanoparticle uptake, biodistribution and relationships with cell and tissue components, thanks to its high resolution. This article aims to overview the transmission electron microscopy techniques used to explore the impact of nanoconstructs on biological systems, highlighting the functional value of ultrastructural morphology, histochemistry and microanalysis as well as their fundamental contribution to the advancement of nanomedicine.