Ionizable lipid nanoparticles deliver mRNA to pancreatic β cells via macrophage-mediated gene transfer

Nanoparticle-Based Pulmonary Immune Engineering

Respiratory conditions represent a significant global healthcare burden impacting hundreds of millions worldwide and necessitating new treatment paradigms. Pulmonary immune engineering using synthetic nanoparticle (NP) platforms can reprogram immune responses for therapeutically beneficial or protective responses directly within the lung tissue. However, effectively localizing these game-changing approaches to the lung remains a significant challenge due to the lung's natural defense. We highlight the target pulmonary immune cells and address advances to localize NPs to the lung via both aerosol and vascular delivery. For each administration route, we discuss physiochemical design rules and recent immune-modulatory successes of synthetic, extracellular vesicle, and cell-mediated NP delivery. We aim to provide readers with an updated summary of this emerging field and offer a roadmap for future research aimed at enhancing the efficacy of pulmonary immunotherapies.

Ionizable Lipids Drive Subcellular Localization and Immune Cell Targeting of Barcoded Nanoparticles in Lung Cancer

To accurately predict the effect of a drug and enhance its potency, it is essential to examine not only the arrival of the carrier and its payload at the target cell but also the final destination of the subcellular organelle because a considerable number of diseases are associated with the malfunctioning of cellular organelles. Here, we present nanoparticle (NP) microscopy via signal amplification of DNA barcodes combined with the multiplexed cyclic immunofluorescence technique for quantifying multiple NP types simultaneously. This technique enhanced the fluorescence signal-to-noise by 15-fold compared to standard fluorescence in situ hybridization, thereby providing a more precise means of analyzing the intra- and interdistribution of three core-shell NPs (G0-P5, 7C1-F5, and C12-D) in vitro and in vivo. The in vitro results demonstrated that in macrophages, nucleic acids condensed with G0-C14 cationic lipids were often located in lysosomes, whereas in tumor cells, nucleic acids were mainly located in mitochondria, regardless of the type of cationic lipid. Together, the in vivo results reveal that nucleic acids condensed with G0-C14 cationic lipids demonstrated the greatest uptake by CD206+ immune cells, whereas nucleic acids condensed with 7C1 and C12-200 cationic lipids exhibited the highest level of uptake by CD206+CD11c+Arg1+ immune cells.

More than a delivery system: the evolving role of lipid-based nanoparticles

Lipid-based nanoparticles, including liposomes and lipid nanoparticles (LNPs), make up an important class of drug delivery systems. Their modularity enables encapsulation of a wide range of therapeutic cargoes, their ease of functionalization allows for incorporation of targeting motifs and anti-fouling coatings, and their scalability facilitates rapid translation to the clinic. While the discovery and early understanding of lipid-based nanoparticles is heavily rooted in biology, formulation development has largely focused on materials properties, such as how liposome and lipid nanoparticle composition can be altered to maximize drug loading, stability and circulation. To achieve targeted delivery and enable improved accumulation of therapeutics at target tissues or disease sites, emphasis is typically placed on the use of external modifications, such as peptide, protein, and polymer motifs. However, these approaches can increase the complexity of the nanocarrier and complicate scale up. In this review, we focus on how our understanding of lipid structure and function in biological contexts can be used to design intrinsically functional and targeted nanocarriers. We highlight formulation-based strategies, such as the incorporation of bioactive lipids, that have been used to modulate liposome and lipid nanoparticle properties and improve their functionality while retaining simple nanocarrier designs. We also highlight classes of naturally occurring lipids, their functions, and how they have been incorporated into lipid-based nanoparticles. We will additionally position these approaches into the historical context of both liposome and LNP development.

Furan-Derived Lipid Nanoparticles for Transporting mRNA to the Central Nervous System

Delivery of mRNA (mRNA) to the central nervous system (CNS) remains a significant challenge. Herein, we design a library of furan-derived lipids and, to our knowledge, for the first time, leverage the meningeal lymphatic vessels (MLVs) route to achieve efficient delivery of mRNA to the brain. These furan-derived lipids were engineered with different furan cores, functional groups, and tails. We found that tetrahydrofuran (THF)-derived lipid nanoparticles (LNPs) generally displayed exceptional mRNA delivery compared to their furan-based counterparts. Specifically, LNPs formulated with four-acetal-tail mono-THF-derived lipid F10T5 and four-acetal-tail di-THF-derived lipid F11T6 demonstrated significantly higher mRNA delivery efficiency to the brain compared with FDA-approved SM102 LNPs. The data revealed that these LNPs bypassed the blood-brain barrier (BBB) via the lymphatic pathway, traveling from deep cervical lymph nodes (dCLNs) to the meninges and subsequently entering brain cells. Collectively, this work provides valuable insights into engineering LNPs and exploring alternative approaches for the delivery of mRNA to the brain.

Intragenic viral silencer element regulates HTLV-1 latency via RUNX complex recruitment

Retroviruses integrate their genetic material into the host genome, enabling persistent infection. Human T cell leukaemia virus type 1 (HTLV-1) and human immunodeficiency virus type 1 (HIV-1) share similarities in genome structure and target cells, yet their infection dynamics differ drastically. While HIV-1 leads to high viral replication and immune system collapse, HTLV-1 establishes latency, promoting the survival of infected cells and, in some cases, leading to leukaemia. The mechanisms underlying this latency preference remain unclear. Here we analyse blood samples from people with HTLV-1 and identify an open chromatin region within the HTLV-1 provirus that functions as a transcriptional silencer and regulates transcriptional burst. The host transcription factor RUNX1 binds to this open chromatin region, repressing viral expression. Mutation of this silencer enhances HTLV-1 replication and immunogenicity, while its insertion into HIV-1 suppresses viral production. These findings reveal a strategy by which HTLV-1 ensures long-term persistence, offering potential insights into retroviral evolution and therapeutic targets.

Nanotherapeutic Wee1 Inhibition Sensitizes Tumor Ferroptosis to Promote Cancer Immunotherapy and Abscopal Effect

The major issue with cancer immunotherapy is the low response rate. So, development of therapeutics enhancing immune responses is an urgent need. Tumor ferroptosis could produce immunogenic cancer cell death, which may improve cancer immunotherapy. However, current ferroptosis inducers may be limited to specific genetic backgrounds of cancer cells. Therefore, sensitization to ferroptosis inducers has also been highly pursued. Here, we found that Wee1 expression was negatively associated with drug sensitivity and positively correlated with an immunosuppressive microenvironment. Further investigation demonstrated that Wee1 inhibition could result in changes of ferroptosis and iron ion homeostasis, regardless of p53 status. Our in vitro results demonstrated the underlying mechanism that Wee1 inhibition primed cancer cells to ferroptosis through mitochondria reactive oxygen species and labile iron-dependent pathways. In order to decrease side effects, we developed an acidic responsive nanoformulation of the Wee1 inhibitor, which can sensitize tumor ferroptosis in vivo and also improve the response of cancer immunotherapy. Combining immunotherapy, nanotherapeutic Wee1 inhibition also produced abscopal effect with up to 55% mice cured that has not been seen before. In summary, nanotherapeutic Wee1 inhibition sensitized ferroptosis to enhance cancer immunotherapy and abscopal effect.

Exploring extracellular vesicles as novel therapeutic agents for intervertebral disc degeneration: delivery, applications, and mechanisms

Intervertebral disc degeneration is a multifactorial degenerative disease that poses a significant threat to the health of the elderly population. Current treatments primarily focus on physical therapy, medication, and surgery to alleviate symptoms associated with disc compression but do not address the progression of degeneration. Therefore, this review aimed to explore the potential of extracellular vesicle therapy as a novel preventive strategy to delay degeneration and enhance tissue repair in intervertebral discs. We cover the pathogenic mechanisms underlying intervertebral disc degeneration, including inflammation, apoptosis, pyroptosis, ferroptosis, autophagy dysregulation, and the roles of non-coding RNAs. Subsequently, we discussed the therapeutic potential of extracellular vesicles and their molecular components, such as proteins, RNAs, and lipids, in modulating these pathways to counter intervertebral disc degeneration. We provides a comprehensive review of the significant role of extracellular vesicle cargo in mediating repair mechanisms. It discusses the functional enhancement advantages exhibited by extracellular vesicles under current bioengineering modifications and drug loading. The challenges and future prospects of utilizing extracellular vesicle therapy to treat this degenerative condition are also summarized.

Developing Therapeutically Enhanced Extracellular Vesicles for Atherosclerosis Therapy

Atherosclerosis is a chronic condition and the leading cause of death worldwide. While statin therapy is the clinical standard, many patients still experience acute cardiovascular events.  To develop better therapies, the group previously delivered microRNA-145 (miR-145) via micellar nanoparticles to vascular smooth muscle cells (VSMCs) to inhibit atherosclerosis. However, for chronic diseases requiring repeat dosing, synthetic nanoparticles have drawbacks such as immunogenic response and low delivery efficiency. To meet this challenge, therapeutically enhanced extracellular vesicles (EVs) are engineered as a biologically-derived nanoparticle modality to mitigate atherosclerosis. A novel strategy is employed to load miR-145 into EVs using ExoMotifs-short miRNA sequences that facilitate miR cargo loading. EVs are further functionalized with a monocyte chemoattractant 1 (MCP-1) peptide, which binds to C-C chemokine receptor 2 upregulated in pathogenic VSMCs. Mouse aortic smooth muscle cell MCP-1-miR-145 EVs restored VSMC gene expression and function in vitro. Moreover, compared to miR-145-loaded synthetic nanoparticles, MCP-1-miR-145 EVs exerted similar therapeutic effects but with 25,000x less miR-145 cargo. Lastly, MCP-1-miR-145 EVs inhibited plaque growth in mid-stage ApoE-/- atherosclerotic mice at a miR-145 dose 5000x less than synthetic nanoparticles. Collectively, it is demonstrated that genetic engineering of VSMCs with miR-145 produces therapeutically boosted EVs that reduce atherosclerosis plaque burden.

Exosome-based nanomedicines for digestive system tumors therapy

Digestive system tumors constitute a major subset of malignancies, consistently ranking among the leading causes of mortality globally. Despite limitations inherent in current therapeutic modalities, recent advancements in targeted therapy and drug delivery systems have led to significant improvements in the efficacy of pharmacotherapy for digestive system tumors. In this context, exosomes - naturally occurring nanoscale vesicles - have emerged as promising drug delivery candidates due to their intrinsic molecular transport capabilities, superior biocompatibility, and targeted recognition of tumor cells. The integration of exosomes into cancer therapeutics represents a novel and potentially transformative approach for treating digestive system tumors, which may drive further progress in this field. This review comprehensively examines the sources, loading mechanisms, and therapeutic efficacy of exosomes in the context of digestive system tumor treatment. Furthermore, it discusses the opportunities and challenges associated with exosomes, offering insights into their future role within the therapeutic armamentarium against digestive tumors.

Amplifying the Antitumor Effect of STING Agonist MSA-2 by Phospholipid Nanoparticles Delivering STING mRNA and Copper-Modified MSA-2 Combination

STING activation is a promising application therapeutic strategy for cancer immunotherapy. In particular, MSA-2 as an oral STING agonist is discovered to have antitumor activity. However, how to improve the antitumor effect of MSA-2 is a very valuable contribution to cancer immunotherapy. Here, we use two strategies to amplify the antitumor effect of MSA-2 by phospholipid nanoparticles delivering STING mRNA and copper-modified MSA-2. We synthesized a new series of ionizable phospholipid nanoparticles and optimized a phospholipid nanoparticle (1AP24) for delivering STING mRNA, increasing the expression of STING protein to bind more MSA-2. Second, we synthesized copper-modified MSA-2 (MSA-2-Cu), which induced cell death by Cu2+ toxicity. Combining 1AP24@STING mRNA and MSA-2-Cu can crucially decrease tumor growth and increase a mouse's survival. It is a new treatment strategy through amplifying the STING pathway.

Fluorinated Ribonucleocarbohydrate Nanoparticles Allow Ultraefficient mRNA Delivery and Protein Expression in Tumor-Associated Myeloid Cells

Ribonucleic acids (RNA) are commonly formulated into lipid nanoparticles (LNP) for in vivo use, but challenges exist with systemic delivery and low in vivo expression efficiency. Inspired by ribonucleoprotein complexes in cells, we created synthetic ribonucleocarbohydrate (RNC) complexes based on cyclodextrin nanoparticles with ferrocenyl fluorocarbons capable of carrying mRNA and additional small-molecule drug payloads, facilitating lysosomal escape and immune stimulation all in the same nanoparticle. We show that this strategy results in highly efficient myeloid cell targeting (dendritic cells and MHC expressing macrophages) and protein expression following systemic administration. The RNC platform should have broad applications in vaccine development, immunosuppression, and immunostimulation for various diseases.

Targeted lipid nanoparticles containing IL-10 mRNA improve outcomes in experimental intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a lethal and highly morbid form of stroke for which there is no disease-specific therapy. Inflammation after ICH is an important mechanism of secondary damage, and the inflamed endothelium in ICH is a promising therapeutic target as it is the gateway for inflammation in the brain. Systemic therapies that target inflammation have been unsuccessful in stroke, in part due to side effects or poor brain delivery. We hypothesized that targeting mRNA encoding IL-10, a potent anti-inflammatory cytokine, to the brain vasculature would improve outcomes in an experimental mouse model of ICH. We manufactured lipid nanoparticles (LNPs) using microfluidics, packaged them with IL-10 mRNA, and decorated them with antibodies against vascular cellular adhesion molecule (VCAM), which can bind the inflamed brain endothelium after ICH. VCAM LNPs distributed to the brain ~4x more than nonspecific LNPs and expressed their cargo in the brain at 10x higher levels. Treatment with VCAM-LNPs containing IL-10 mRNA led to ~69% reduction in hematoma size at 72 hours after ICH and ~65% improvement in motor behavior in our model, with no improvement in vascular leakage. Finally, we observed that VCAM-LNPs primarily target infiltrated macrophages and neutrophils. VCAM-IL10-LNPs significantly increased plasma and brain levels of IL10. Our data provide preliminary data for a promising therapeutic and delivery strategy for ICH, and shed light on the relationship between inflammation and vascular leakage. Future experiments will seek to understand how serial dosing affects LNP expression in our model and whether treatment at later time points after ICH can still confer therapeutic effects.

A Polymeric mRNA Vaccine Featuring Enhanced Site-Specific mRNA Delivery and Inherent STING-Stimulating Performance for Tumor Immunotherapy

The development of mRNA delivery carriers with innate immune stimulation functions has emerged as a focal point in the field of mRNA vaccines. Nonetheless, the expression of mRNA in specific sites and innate immune stimulation at specific sites are prerequisites for ensuring the safety of mRNA vaccines. Based on the synthetic PEIRs carriers library, this study identifies an innovative mRNA delivery carrier named POctS with the following characteristics: 1) simultaneously possessing high mRNA delivery efficiency and stimulator of interferon genes (STING) stimulation function. 2) Leveraging the distinctive site-specific delivery capabilities of POctS, the expression of mRNA at specific sites and the activation of innate immune responses at designated sites are achieved, minimizing formulation toxicity and maximizing the vaccine performance. 3) Tailoring two types of mRNA vaccines based on POctS according to the immune infiltration status of different types of tumors. Briefly, POctS-loading ovalbumin (OVA) mRNA as a tumor antigen vaccine achieves the prevention and treatment of melanoma in mice. Further, POctS-loading mixed lineage kinase domain-like protein (MLKL) mRNA as an in situ tumor vaccine effectively treats orthotopic pancreatic cancer in mice. This delivery carrier offers a feasible mRNA vaccine-based immunotherapy strategy for various types of tumors.

Janus dendritic ionizable lipids with fine designed headgroup and tails to improve mRNA delivery efficiency

Lipid nanoparticles (LNP) are recognized as the most efficient non-viral carriers for the delivery of nucleic acids including small interfering RNA (siRNA) and messenger RNA (mRNA). Ionizable lipid within the system is pivotal component influencing encapsulation, endosomal escape, delivery efficiency and immunogenicity. Accordingly, the precision design of ionizable lipids is a key step in the development of LNP. In this report, we constructed sixteen Janus dendritic ionizable lipids by varying numbers and alkyl chain length of tails based on different ionizable head containing hydroxyl and tertiary amine groups. The corresponding LNP were prepared by using microfluidic mixing device, with all samples exhibiting particle size around 100 nm and polydispersity index (PDI) below 0.2. In vivo validation demonstrates that two optimized ionizable lipids containing two hydroxy groups, two tertiary amines and six hydrophobic chain tails (U-502, U-503) show superior delivery efficiency compared to lipids with less tails and commercial ALC-0315. Hematoxylin and Eosin (H&E) staining of tissues, immunogenicity, liver and kidney function tests additionally confirm that both ionizable lipids have favorable biocompatibility and low in vivo toxicity. Lysosomal escape and cell transfection data verify the in vitro delivery efficacy of these LNP. Taken together, Janus dendritic lipids with fine designed ionizable head and multiple hydrophobic tails have improved mRNA delivery efficiency and biosafety, which may be promise in the development of delivery system.

Recent advances in functional lipid-based nanomedicines as drug carriers for organ-specific delivery

Lipid-based nanoparticles have emerged as promising drug delivery systems for a wide range of therapeutic agents, including plasmids, mRNA, and proteins. However, these nanoparticles still encounter various challenges in drug delivery, including drug leakage, poor solubility, and inadequate target specificity. In this comprehensive review, we present an in-depth investigation of four distinct drug delivery methods: liposomes, lipid nanoparticle formulations, solid lipid nanoparticles, and nanoemulsions. Moreover, we explore recent advances in lipid-based nanomedicines (LBNs) for organ-specific delivery, employing ligand-functionalized particles that specifically target receptors in desired organs. Through this strategy, LBNs enable direct and efficient drug delivery to the intended organs, leading to superior DNA or mRNA expression outcomes compared to conventional approaches. Importantly, the development of novel ligands and their judicious combination holds promise for minimizing the side effects associated with nonspecific drug delivery. By leveraging the unique properties of lipid-based nanoparticles and optimizing their design, researchers can overcome the limitations associated with current drug delivery systems. In this review, we aim to provide valuable insights into the advancements, challenges, and future directions of lipid-based nanoparticles in the field of drug delivery, paving the way for enhanced therapeutic strategies with improved efficacy and reduced adverse effects.

Macrophage-targeted Mms6 mRNA-lipid nanoparticles promote locomotor functional recovery after traumatic spinal cord injury in mice

Traumatic spinal cord injury (SCI) causes severe central nervous system damage. M2 macrophages within the lesion are crucial for SCI recovery. Our previous research revealed that M2 macrophages transfected with magnetotactic bacteria-derived Mms6 gene can resist ferroptosis and enhance SCI recovery. To address the limitations of M2 macrophage transplantation, we developed lipid nanoparticles (LNPs) encapsulating Mms6 mRNA targeting macrophages (Mms6 mRNA-PS/LNPs). The targeting efficiency and therapeutic effect of these LNPs in SCI mice were evaluated. Intravenous administration of Mms6 mRNA-PS/LNPs delivered more Mms6 mRNAs to lesion-site macrophages than those in the Mms6 mRNA-LNP group, which resulted in enhancing motor function recovery, reducing lesion area and scar formation, and promoting neuronal survival and nerve fiber repair. These effects were nullified when macrophages were depleted. These findings suggest that macrophage-targeted delivery of Mms6 mRNA is a promising therapeutic strategy for promoting spinal cord repair and motor function recovery in patients with traumatic SCI.

Exosome-mediated effects of BRCA1 on cardiovascular artery disease

The progression of coronary artery disease atherosclerosis (CAD) is closely associated with cardiomyocyte apoptosis and inflammatory responses. This study focused on investigating the impact of BRCA1 in exosomes (Exo) derived from M1 macrophages on CAD. Through the analysis of single-cell RNA-seq datasets, significant communication between macrophages and cardiomyocytes in CAD patients was observed. BRCA1, identified as a significant apoptosis-related gene, was pinpointed through the assessment of differential gene expression and weighted gene co-expression network analysis (WGCNA). Experimental procedures involved BRCA1 lentivirus transfection of M1 macrophages, isolation of Exo for application to cardiomyocytes and smooth muscle cells, cell viability assessments, and characterization of Exo. The results showed that BRCA1-Exo from M1 macrophages induced cardiomyocyte apoptosis and affected smooth muscle cell behavior. In vivo studies further supported the exacerbating effects of BRCA1-Exo on CAD progression. Overall, the involvement of Exo carrying BRCA1 from M1 macrophages is evident in the induction of cardiomyocyte apoptosis and the regulation of smooth muscle cell behaviors, thereby contributing to CAD atherosclerosis progression. These findings unveil novel molecular targets that could have potential implications for CAD treatment strategies.

Developing mRNA Nanomedicines with Advanced Targeting Functions

The emerging messenger RNA (mRNA) nanomedicines have sprung up for disease treatment. Developing targeted mRNA nanomedicines has become a thrilling research hotspot in recent years, as they can be precisely delivered to specific organs or tissues to enhance efficiency and avoid side effects. Herein, we give a comprehensive review on the latest research progress of mRNA nanomedicines with targeting functions. mRNA and its carriers are first described in detail. Then, mechanisms of passive targeting, endogenous targeting, and active targeting are outlined, with a focus on various biological barriers that mRNA may encounter during in vivo delivery. Next, emphasis is placed on summarizing mRNA-based organ-targeting strategies. Lastly, the advantages and challenges of mRNA nanomedicines in clinical translation are mentioned. This review is expected to inspire researchers in this field and drive further development of mRNA targeting technology.

Intraperitoneal administration of mRNA encoding interleukin-12 for immunotherapy in peritoneal carcinomatosis

Peritoneal carcinomatosis is an advanced stage of cancer with very limited treatment options. Locoregional immunotherapy is being evaluated as a way to improve efficacy and limit toxicity. This study assessed the efficacy of a cationic polymer/lipid-based transfection compound in delivering mRNA molecules intraperitoneally. Our investigation of the transfer of luciferase mRNA in murine models of peritoneal carcinomatosis revealed preferential luciferase expression in the omentum upon the intraperitoneal administration of complexed mRNAs. Macrophages were identified as key cells that capture and express the mRNA complexes, and accordingly, depletion of resident macrophages led to reduced reporter luciferase expression. To explore the therapeutic potential of this approach, mRNA complexes encoding single-chain interleukin-12 (IL12), an immunostimulatory molecule (mRNA-IL12), were investigated. mRNA-IL12-treated mice exhibited a significant survival advantage in models of peritoneal carcinomatosis and acquired immune memory, as shown upon subcutaneous rechallenge. Tumor microenvironment analyses revealed increased numbers of CD4+ and CD8+ T cells with a more proliferative phenotype, accompanied by decreased myeloid populations in the omentum. Overall, our study underscores the potential of mRNA complexes for efficient mRNA delivery, eliciting effective antitumor responses and modulating the tumor microenvironment to treat peritoneal carcinomatosis.

Blood-brain-barrier-crossing lipid nanoparticles for mRNA delivery to the central nervous system

The systemic delivery of mRNA molecules to the central nervous system is challenging as they need to cross the blood-brain barrier (BBB) to reach into the brain. Here we design and synthesize 72 BBB-crossing lipids fabricated by conjugating BBB-crossing modules and amino lipids, and use them to assemble BBB-crossing lipid nanoparticles for mRNA delivery. Screening and structure optimization studies resulted in a lead formulation that has substantially higher mRNA delivery efficiency into the brain than those exhibited by FDA-approved lipid nanoparticles. Studies in distinct mouse models show that these BBB-crossing lipid nanoparticles can transfect neurons and astrocytes of the whole brain after intravenous injections, being well tolerated across several dosage regimens. Moreover, these nanoparticles can deliver mRNA to human brain ex vivo samples. Overall, these BBB-crossing lipid nanoparticles deliver mRNA to neurons and astrocytes in broad brain regions, thereby being a promising platform to treat a range of central nervous system diseases.

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of type 1 diabetes

AIMS/HYPOTHESIS

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death protein 1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesised that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death.

METHODS

Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry and ELISA. EV PD-L1 binding to PD-1 was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8+ T cells. Plasma EV and soluble PD-L1 were assayed in the plasma of islet autoantibody-positive (Ab+) individuals or individuals with recent-onset type 1 diabetes and compared with levels in non-diabetic control individuals.

RESULTS

PD-L1 protein co-localised with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. Treatment with IFN-α or IFN-γ for 24 h induced a twofold increase in EV PD-L1 cargo without a corresponding increase in the number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8+ T cells. Plasma EV PD-L1 levels were increased in Ab+individuals, particularly in those positive for a single autoantibody. Additionally, in Ab+ individuals or those who had type 1 diabetes, but not in control individuals, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV PD-L1 could be protective for residual beta cell function.

CONCLUSIONS/INTERPRETATION

IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8+ T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in Ab+ individuals than in control individuals. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Unlocking Transplant Tolerance with Biomaterials

For patients suffering from organ failure due to injury or autoimmune disease, allogeneic organ transplantation with chronic immunosuppression is considered the god standard in terms of clinical treatment. However, the true "holy grail" of transplant immunology is operational tolerance, in which the recipient exhibits a sustained lack of alloreactivity toward unencountered antigen presented by the donor graft. This outcome is resultant from critical changes to the phenotype and genotype of the immune repertoire predicated by the activation of specific signaling pathways responsive to soluble and mechanosensitive cues. Biomaterials have emerged as a medium for interfacing with and reprogramming these endogenous pathways toward tolerance in precise, minimally invasive, and spatiotemporally defined manners. By viewing seminal and contemporary breakthroughs in transplant tolerance induction through the lens of biomaterials-mediated immunomodulation strategies-which include intrinsic material immunogenicity, the depot effect, graft coatings, induction and delivery of tolerogenic immune cells, biomimicry of tolerogenic immune cells, and in situ reprogramming-this review emphasizes the stunning diversity of approaches in the field and spotlights exciting future directions for research to come.

Nanostructured lipid carriers based mRNA vaccine leads to a T cell-inflamed tumour microenvironment favourable for improving PD-1/PD-L1 blocking therapy and long-term immunity in a cold tumour model

BACKGROUND

mRNA-based cancer vaccines show promise in triggering antitumour immune responses. To combine them with existing immunotherapies, the intratumoral immune microenvironment needs to be deeply characterised. Here, we test nanostructured lipid carriers (NLCs), the so-called Lipidots®, for delivering unmodified mRNA encoding Ovalbumin (OVA) antigen to elicit specific antitumour responses.

METHODS

We evaluated whether NLC OVA mRNA complexes activate dendritic cells (DCs) in vitro and identified the involved signalling pathways using specific inhibitors. We tested the anti-tumoral impact of Ova mRNA vaccine in B16-OVA and E.G7-OVA cold tumour-bearing C57Bl6 female mice as well as its synergy effect with an anti-PD-1 therapy by following the tumour growth and performing immunophenotyping of innate and adaptive immune cells. The intratumoral vaccine-related gene signature was assessed by RNA-sequencing. The immune memory response was assessed by re-challenging surviving treated mice with tumour cells.

FINDINGS

Our vaccine activates DCs in vitro through the TLR4/8 and ROS signalling pathways and induces specific T cell activation while exhibits significant preventive and therapeutic antitumour efficacy in vivo. A profound intratumoral remodelling of the innate and adaptive immunity in association with an increase in the gene expression of chemokines (Cxcl10, Cxcl11, Cxcl9) involved in CD8+ T cell attraction were observed in immunised mice. The combination of vaccine and anti-PD-1 therapy improves the rates of complete responses and memory immune responses compared to monotherapies.

INTERPRETATION

Lipidots® are effective platform for the development of vaccines against cancer based on mRNA delivery. Their combination with immune checkpoint blockers could counter tumour resistance and promote long-term antitumour immunity.

FUNDING

This work was supported by Inserm Transfert, la Région Auvergne Rhône Alpes, FINOVI, and the French Ministry of Higher Education, research and innovation (LipiVAC, COROL project, funding reference N° 2102992411).

Maternal milk cell components are uptaken by infant liver macrophages via extracellular vesicle mediated transport

Milk is a multifaceted biofluid that is essential for infant nutrition and development, yet its cellular and bioactive components, particularly maternal milk cells, remain understudied. Early research on milk cells indicated that they cross the infant's intestinal barrier and accumulate within systemic organs. However, due to the absence of modern analytical techniques, these studies were limited in scope and mechanistic analysis. To overcome this knowledge gap, we have investigated the transintestinal transport of milk cells and components in pups over a 21-day period. Studies employed a mT/mG foster nursing model in which milk cells express a membrane-bound fluorophore, tdTomato. Using flow cytometry, we tracked the transport of milk cell-derived components across local and systemic tissues, including the intestines, blood, thymus, mesenteric lymph nodes, and liver. These experiments identified milk-derived fluorescent signals in intestinal epithelial and immune cells as well as liver macrophages in 7-day-old pups. However, the minute numbers of macrophages in mouse milk suggest that maternal cells are not systemically accumulating in the infant; instead, pup macrophages are consuming milk cell membrane components, such as apoptotic bodies or extracellular vesicles (EVs). Ex vivo experiments using primary macrophages support this hypothesis, showing that immune cells preferentially consumed EVs over milk cells. Together, these data suggest a more complex interplay between milk cells and the infant's immune and digestive systems than previously recognized and highlight the need for future research on the role of milk cells in infant health.

Protein corona formed on lipid nanoparticles compromises delivery efficiency of mRNA cargo

Lipid nanoparticles (LNPs) are the most clinically advanced nonviral RNA-delivery vehicles, though challenges remain in fully understanding how LNPs interact with biological systems. In vivo , proteins form an associated corona on LNPs that redefines their physicochemical properties and influences delivery outcomes. Despite its importance, the LNP protein corona is challenging to study owing to the technical difficulty of selectively recovering soft nanoparticles from biological samples. Herein, we developed a quantitative, label-free mass spectrometry-based proteomics approach to characterize the protein corona on LNPs. Critically, this protein corona isolation workflow avoids artifacts introduced by the presence of endogenous nanoparticles in human biofluids. We applied continuous density gradient ultracentrifugation for protein-LNP complex isolation, with mass spectrometry for protein identification normalized to protein composition in the biofluid alone. With this approach, we quantify proteins consistently enriched in the LNP corona including vitronectin, C-reactive protein, and alpha-2-macroglobulin. We explore the impact of these corona proteins on cell uptake and mRNA expression in HepG2 human liver cells, and find that, surprisingly, increased levels of cell uptake do not correlate with increased mRNA expression in part likely due to protein corona-induced lysosomal trafficking of LNPs. Our results underscore the need to consider the protein corona in the design of LNP-based therapeutics.

Abstract Figure

Peptide-Functionalized Lipid Nanoparticles for Targeted Systemic mRNA Delivery to the Brain

Systemic delivery of large nucleic acids, such as mRNA, to the brain remains challenging in part due to the blood-brain barrier (BBB) and the tendency of delivery vehicles to accumulate in the liver. Here, we design a peptide-functionalized lipid nanoparticle (LNP) platform for targeted mRNA delivery to the brain. We utilize click chemistry to functionalize LNPs with peptides that target receptors overexpressed on brain endothelial cells and neurons, namely the RVG29, T7, AP2, and mApoE peptides. We evaluate the effect of LNP targeting on brain endothelial and neuronal cell transfection in vitro, investigating factors such as serum protein adsorption, intracellular trafficking, endothelial transcytosis, and exosome secretion. Finally, we show that LNP peptide functionalization enhances mRNA transfection in the mouse brain and reduces hepatic delivery after systemic administration. Specifically, RVG29 LNPs improved neuronal transfection in vivo, establishing its potential as a nonviral platform for delivering mRNA to the brain.

A Chemoinformatic-Guided Synthesis of a Spleen-Expressing mRNA Lipid Nanoparticle Platform

mRNA lipid nanoparticles (LNPs) are a powerful technology that are actively being investigated for their ability to prevent, treat, and study disease. However, a major limitation remains: achieving extrahepatic mRNA expression. The development of new carriers could enable the expression of mRNA in non-liver targets, thus expanding the utility of mRNA-based medicines. In this study, we use a combination of chemoinformatic-guided material synthesis and design of experiment optimization for the development of a spleen-expressing lipid nanoparticle (SE-LNP). We begin with the synthesis of a novel cholesterol derivative followed by SE-LNP formulation and design of experiment-guided optimization to identify three lead SE-LNPs. We then evaluate their in vitro delivery mechanism, in vivo biodistribution, and protein expression in mice, ultimately achieving spleen-preferential expression. The goal of this paper is thus to create LNPs that preferentially express mRNA in the spleen upon intravenous delivery, demonstrating the potential of LNPs to modulate gene expression in extrahepatic tissues for disease treatment.

Gene Therapy: Towards a New Era of Medicine

Over the past years, many significant advances have been made in the field of gene therapy and shown promising results in clinical trials conducted. Gene therapy aims at modifying or replacing a defective, inefficient, or nonfunctional gene with a healthy, functional gene by administration of genome material into the cell to cure genetic diseases. Various methods have been devised to do this by using several viral and non-viral vectors which are either administered by in vivo or ex vivo technique. Viral vectors are best suitable for this therapy due to their potential to invade cells and deliver their genetic material whereas non-viral vectors are less efficient than viral vectors but possess some advantages such as less immunogenic response and large gene carrying capacity. Recent advances in biotechnology such as CRISPR-Cas9 mediated genome engineering and Cancer treatment with Chimeric antigen receptor (CAR) T-cell therapy are addressed in this review. This review article also delves into some recent research studies, gene therapy trials, and its applications, laying out future hopes for gene therapy in the treatment of various diseases namely haemophilia, Muscular dystrophy, SCID, Sickle cell disease, Familial Hypercholesterolemia, Cystic Fibrosis. Additionally, it also includes various nanoformulations and clinical trial data related to gene therapy.

Gastrointestinal Device-Mediated Delivery of mRNA-Lipid Nanoparticles Achieves Distinct Expression and Biodistribution in Mice and Pigs

Recent investigations into autonomous ingestible microjet devices have demonstrated the feasibility of delivering many drug modalities directly into the gastrointestinal (GI) wall via the oral route. However, the expression and biodistribution of mRNA after such injections remain unexplored. mRNA-lipid nanoparticles (mRNA-LNPs) are promising therapeutics for treating or vaccinating against many diseases and pathogens. Today, mRNA-LNPs are given as injections, necessitating trained medical personnel and resulting in reduced patient compliance. Here, we elucidate the expression and biodistribution of mRNA-LNPs after injection into the gastric and intestinal walls of mice and minipigs. We see a controlled release of mRNA from the stomach and intestine with mRNA in both plasma and lymph nodes, leading to a broad biodistribution profile, which could lead to better immunization after vaccination. Our results substantiate the argument that ingestible microjet devices facilitate a viable route of administration for use as an alternative to injections of mRNA-LNP.

The Application of Nanomaterials in the Treatment of Pancreatic-Related Diseases

Pancreatic diseases, typically including pancreatic cancer, pancreatitis, and diabetes, pose enormous threats to people's lives and health. To date, therapeutics with high therapeutic efficacy and low side effects are still challenging. With the development of nanotechnology, nanomaterials have successfully been applied in pancretic disease treatment. Here, we first introduce the diversity of nanomaterials and the effects of their different physicochemical properties on pancreatic function. Following this, we analyze the potential of nanomaterials to enhance pancreatic targeting by overcoming the challenges of traditional delivery methods through surface modifications, structural adjustments, and optimized drug loading. Then, we introduce the application of structurally optimized nanomaterials to pancreatic-related diseases. For instance, on pancreatic cancer (as drug delivery platforms, for the promotion of radiation therapy, and as multifunctional tools), pancreatitis (as drug delivery systems, anti-inflammatory and anti-fibrotic agents), and diabetes (as insulin delivery carriers, for protecting pancreatic β cells, and for improving insulin resistance). Through analysis of the progress of current research, we summarize how nanomaterials can enhance treatment efficacy while minimizing side effects. Finally, we look forward to the prospects of nanomaterials in pancreatic disease treatment.

The journey of nanoparticles in the abdominal cavity: Exploring their in vivo fate and impact factors

Peritoneal carcinomatosis (PC) is caused by metastasis of primary tumor cells from intra-abdominal organs to the peritoneal surface. Intraperitoneal (IP) chemotherapy allows close contact of high concentrations of therapeutic agents with cancer cells in the peritoneal cavity to prolong patient survival. However, conventional IP chemotherapy is prone to rapid elimination from the peritoneal cavity and lacks specificity towards cancer cells. To address these challenges, there is an imperative demand for exploiting novel drug delivery systems to enhance drug retention in the peritoneal cavity and target PC cells. Therefore, in this review, we first recapitulate the physiological structures and barriers associated with IP drug delivery, highlighting the in vivo fate of nanoparticles (NPs) after IP administration. Furthermore, the influence of physicochemical properties (particle size, charge, surface modification, and carrier composition) on the in vivo fate of NPs is discussed. Perspectives on the rational design of NPs for IP therapy and recent clinical progress are also provided.

Navigating the intricate in-vivo journey of lipid nanoparticles tailored for the targeted delivery of RNA therapeutics: a quality-by-design approach

RNA therapeutics, such as mRNA, siRNA, and CRISPR-Cas9, present exciting avenues for treating diverse diseases. However, their potential is commonly hindered by vulnerability to degradation and poor cellular uptake, requiring effective delivery systems. Lipid nanoparticles (LNPs) have emerged as a leading choice for in vivo RNA delivery, offering protection against degradation, enhanced cellular uptake, and facilitation of endosomal escape. However, LNPs encounter numerous challenges for targeted RNA delivery in vivo, demanding advanced particle engineering, surface functionalization with targeting ligands, and a profound comprehension of the biological milieu in which they function. This review explores the structural and physicochemical characteristics of LNPs, in-vivo fate, and customization for RNA therapeutics. We highlight the quality-by-design (QbD) approach for targeted delivery beyond the liver, focusing on biodistribution, immunogenicity, and toxicity. In addition, we explored the current challenges and strategies associated with LNPs for in-vivo RNA delivery, such as ensuring repeated-dose efficacy, safety, and tissue-specific gene delivery. Furthermore, we provide insights into the current clinical applications in various classes of diseases and finally prospects of LNPs in RNA therapeutics.

Lipid Nanoparticle-Mediated Oip5-as1 Delivery Preserves Mitochondrial Function in Myocardial Ischemia/Reperfusion Injury by Inhibiting the p53 Pathway

Myocardial ischemia/reperfusion (MI/R) injury, a major contributor to poor prognosis in patients with acute myocardial infarction, currently lacks effective therapeutic strategies in clinical practice. The long noncoding RNA (lncRNA) Oip5-as1 can regulate various cellular processes, such as cell proliferation, differentiation, and survival. Oip5-as1 may have potential as a therapeutic target for MI/R injury as its upregulated expression has been associated with reduced infarct size and improved cardiac function in animal models, although how to effectively and safely overexpress Oip5-as1 in vivo remains unclear. Lipid nanoparticles (LNPs) are a versatile technology for targeted drug delivery in numerous therapeutic applications. Herein, we aimed to assess the therapeutic efficacy and safety of LNPs coloaded with Oip5-as1 and a cardiomyocyte-specific binding peptide (LNP@Oip5-as1@CMP) in a murine model of MI/R injury. To achieve this, LNP@Oip5-as1@CMP was synthesized via ethanol injection method. The structural components of LNP@Oip5-as1@CMP were physicochemically analyzed. A hypoxia/reoxygenation (H/R) model in HL-1 cells and coronary artery ligation in mice were used to simulate MI/R injury. Our results demonstrated that LNPs designed for cardiomyocyte targeting and efficient Oip5-as1 delivery were successfully synthesized. In HL-1 cells, LNP@Oip5-as1@CMP treatment significantly reduced mitochondrial apoptosis caused by H/R injury. In the murine MI/R model, the intravenous administration of LNP@Oip5-as1@CMP significantly decreased myocardial infarct size and improved cardiac function. Mechanistic investigations revealed that Oip5-as1 delivery inhibited the p53 signaling pathway. However, the cardioprotective effects of Oip5-as1 were abrogated by administrating Nutlin-3a, a p53 activator. Furthermore, no signs of major organ damage were detected after LNP@Oip5-as1@CMP injection. Our study reveals the therapeutic potential of LNPs for targeted Oip5-as1 delivery in mitigating MI/R injury. These findings pave the way for advanced targeted treatments in cardiovascular diseases, emphasizing the promise of lncRNA-based therapies.

Synergistic integration of mRNA-LNP with CAR-engineered immune cells: Pioneering progress in immunotherapy

Chimeric antigen receptor T cell (CAR-T) therapy has emerged as a revolutionary approach in the treatment of malignancies. Despite its remarkable successes, this field continues to grapple with challenges such as scalability, safety concerns, limited therapeutic effect, in vivo persistence, and the need for precise control over CAR expression. In the post-pandemic era of COVID-19 vaccine immunization, the application of messenger RNA (mRNA) encapsulated within lipid nanoparticles (LNPs) has recently garnered significant attention as a potential solution to address these challenges. This review delves into the dynamic landscape of mRNA-LNP technology and its potential implications for CAR-engineered immune cell-based immunotherapy.

Simplified Lipid Nanoparticles for Tissue- And Cell-Targeted mRNA Delivery Facilitate Precision Tumor Therapy in a Lung Metastasis Mouse Model

mRNA-based applications have achieved remarkable success in the development of next-generation vaccines and the treatment of diverse liver diseases. Overcoming the challenge of delivering mRNA to extrahepatic tissues, especially specific cells within tissues, is crucial for precision therapy. In this study, a platform is developed for selective mRNA delivery to desired cells within tissues by combining lipid nanoparticle (LNP)-based targeted delivery with mRNA sequence-controlled expression. Through systematic optimization, a three-component LNP platform is developed, enabling targeted mRNA delivery to the lung, liver, and spleen. The incorporation of unique microRNA target sites into the mRNA scaffold further enhances control over protein translation in specific cells within the target tissue. This combined strategy, named SELECT (Simplified LNP with Engineered mRNA for Cell-type Targeting), demonstrates its efficacy in distinguishing mRNA expression between tumor and normal cells based on intracellular microRNA abundance. SELECT encapsulating mRNA encoding a tumor-specific cytotoxic protein, human ELANE, exhibits selective mRNA delivery to tumor lesions and significant inhibition of tumor growth in a mouse model of melanoma lung metastasis. Overall, SELECT has great potential as a new precision tumor treatment approach and also offers promising prospects for other mRNA therapies targeting specific cell types.

Tuning Lipid Nanoparticles for RNA Delivery to Extrahepatic Organs

RNA therapeutics have been successfully transitioned into clinical applications. Lipid nanoparticles (LNPs) are widely employed as nonviral delivery vehicles for RNA therapeutics in commercial vaccine and gene therapy products. However, the bottleneck in expanding the clinical applications of LNP-based RNA therapeutics lies in the tendency of these nanoparticles to preferentially accumulate in the liver. This challenge underscores the need to design LNPs capable of delivering RNA to organs beyond the liver. In this perspective, recent progress is discussed in developing strategies for designing LNPs to deliver RNA to extrahepatic organs. Organ-selective targeting capability is achieved by either altering the composition of the LNP formulation or chemically modifying the ionizable lipid component. Both approaches result in changes in the physicochemical properties of the LNPs, which subsequently alters the composition of the biomolecular corona that adsorbs onto its surface following administration. The biomolecular corona is a known mechanism that mediates organ-selective LNP delivery. Furthermore, this perspective aims to provide an outlook on shaping the next-generation LNP delivery platforms. Potential efforts include targeting specific cell types, improving the safety profile of LNPs, and developing strategies to overcome physiological barriers against organ-specific delivery.

Breaking the final barrier: Evolution of cationic and ionizable lipid structure in lipid nanoparticles to escape the endosome

In the past decade, nucleic acid therapies have seen a boon in development and clinical translation largely due to advances in nanotechnology that have enabled their safe and targeted delivery. Nanoparticles can protect nucleic acids from degradation by serum enzymes and can facilitate entry into cells. Still, achieving endosomal escape to allow nucleic acids to enter the cytoplasm has remained a significant barrier, where less than 5% of nanoparticles within the endo-lysosomal pathway are able to transfer their cargo to the cytosol. Lipid-based drug delivery vehicles, particularly lipid nanoparticles (LNPs), have been optimized to achieve potent endosomal escape, and thus have been the vector of choice in the clinic as demonstrated by their utilization in the COVID-19 mRNA vaccines. The success of LNPs is in large part due to the rational design of lipids that can specifically overcome endosomal barriers. In this review, we chart the evolution of lipid structure from cationic lipids to ionizable lipids, focusing on structure-function relationships, with a focus on how they relate to endosomal escape. Additionally, we examine recent advancements in ionizable lipid structure as well as discuss the future of lipid design.

Thin-film freeze-drying of an influenza virus hemagglutinin mRNA vaccine in unilamellar lipid nanoparticles with blebs

Messenger RNA (mRNA) vaccines have revolutionized the fight against infectious diseases and are poised to transform other therapeutic areas. Lipid nanoparticles (LNP) represent the most successful delivery system for mRNA. While the mRNA-LNP products currently in clinics are stored as frozen suspensions, there is evidence that freeze-drying mRNA-LNP into dry powders can potentially enable their storage and handling at non-freezing temperatures. Previously, we successfully applied thin-film freeze-drying (TFFD) to transform a polyadenylic acid [poly(A)]-LNP formulation from a liquid suspension to dry powders. The poly(A)-LNP were structurally multilamellar spheres without blebs, but the mRNA vaccines in clinics are comprised of mRNA-LNP that are structurally spheres surrounded by a unilamellar lipid bilayer, with some containing blebs, and it was reported that the presence of blebs increases the sensitivity of mRNA-LNP to freeze-drying-induced stress. In the present study, using an influenza A virus hemagglutinin (HA) mRNA in LNP that were structurally similar to that in the COVID-19 mRNA vaccines currently in clinic, we studied the effect of TFFD on the physical properties, internal structure, as well as immunogenicity of the HA mRNA-LNP vaccine. We concluded that TFFD can be utilized to prepare dry powders of the HA mRNA-LNP, but a sufficient amount of excipients were needed to minimize changes in the physical properties, structure, and immunogenicity of the HA mRNA-LNP vaccine.

Emerging Roles of ncRNAs in Type 2 Diabetes Mellitus: From Mechanisms to Drug Discovery

Type 2 diabetes mellitus (T2DM), a high-incidence chronic metabolic disorder, has emerged as a global health issue, where most patients need lifelong medication. Gaining insights into molecular mechanisms involved in T2DM development is expected to provide novel strategies for clinical prevention and treatment. Growing evidence validates that non-coding RNAs (ncRNAs) including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) function as crucial regulators in multiple biological processes of T2DM, inspiring various potential targets and drug candidates. In this review, we summarize the current understanding of ncRNA roles in T2DM and discuss the potential use of ncRNAs as targets and active molecules for drug discovery.

Advanced Nanotechnology-Based Nucleic Acid Medicines

Nucleic acid medicines are a highly attractive modality that act in a sequence-specific manner on target molecules. To date, 21 such products have been approved by the Food and Drug Administration. However, the development of nucleic acid medicines continues to face various challenges, including tissue and cell targeting as well as intracellular delivery. Numerous research groups are addressing these issues by advancing the development of nucleic acid medicines through nanotechnology. In countries other than Japan (including Europe and the USA), >40 nanotechnology-based nucleic acid medicines have been tested in clinical trials, and 15 clinical trials are ongoing. In Japan, three phase I trials are ongoing, and future results are awaited. The review summarizes the latest research in the nanotechnology of nucleic acid medicines and statuses of clinical trials in Japan, with expectations of further evolutions.

Composition of lipid nanoparticles for targeted delivery: application to mRNA therapeutics

Today, lipid nanoparticles (LNPs) are some of the main delivery systems for mRNA-based therapeutics. The scope of LNP applications in terms of RNA is not limited to antiviral vaccines but encompasses anticancer drugs and therapeutics for genetic (including rare) diseases. Such widespread use implies high customizability of targeted delivery of LNPs to specific organs and tissues. This review addresses vector-free options for targeted delivery of LNPs, namely the influence of lipid composition of these nanoparticles on their biodistribution. In the review, experimental studies are examined that are focused on the biodistribution of mRNA or of the encoded protein after mRNA administration via LNPs in mammals. We also performed a comprehensive analysis of individual lipids' functional groups that ensure biodistribution to desired organs. These data will allow us to outline prospects for further optimization of lipid compositions of nanoparticles for targeted delivery of mRNA therapeutics.

Advances in the design and delivery of RNA vaccines for infectious diseases

RNA medicines represent a paradigm shift in treatment and prevention of critical diseases of global significance, e.g., infectious diseases. The highly successful messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were developed at record speed during the coronavirus disease 2019 pandemic. A consequence of this is exceptionally shortened vaccine development times, which in combination with adaptability makes the RNA vaccine technology highly attractive against infectious diseases and for pandemic preparedness. Here, we review state of the art in the design and delivery of RNA vaccines for infectious diseases based on different RNA modalities, including linear mRNA, self-amplifying RNA, trans-amplifying RNA, and circular RNA. We provide an overview of the clinical pipeline of RNA vaccines for infectious diseases, and present analytical procedures, which are paramount for characterizing quality attributes and guaranteeing their quality, and we discuss future perspectives for using RNA vaccines to combat pathogens beyond SARS-CoV-2.

Beta cell extracellular vesicle PD-L1 as a novel regulator of CD8+ T cell activity and biomarker during the evolution of Type 1 Diabetes

Aims/hypothesis

Surviving beta cells in type 1 diabetes respond to inflammation by upregulating programmed death-ligand 1 (PD-L1) to engage immune cell programmed death-1 (PD-1) and limit destruction by self-reactive immune cells. Extracellular vesicles (EVs) and their cargo can serve as biomarkers of beta cell health and contribute to islet intercellular communication. We hypothesized that the inflammatory milieu of type 1 diabetes increases PD-L1 in beta cell EV cargo and that EV PD-L1 may protect beta cells against immune-mediated cell death.

Methods

Beta cell lines and human islets were treated with proinflammatory cytokines to model the proinflammatory type 1 diabetes microenvironment. EVs were isolated using ultracentrifugation or size exclusion chromatography and analysed via immunoblot, flow cytometry, and ELISA. EV PD-L1: PD-1 binding was assessed using a competitive binding assay and in vitro functional assays testing the ability of EV PD-L1 to inhibit NOD CD8 T cells. Plasma EV and soluble PD-L1 were assayed in plasma of individuals with islet autoantibody positivity (Ab+) or recent-onset type 1 diabetes and compared to non-diabetic controls.

Results

PD-L1 protein colocalized with tetraspanin-associated proteins intracellularly and was detected on the surface of beta cell EVs. 24-h IFN-α or IFN-γ treatment induced a two-fold increase in EV PD-L1 cargo without a corresponding increase in number of EVs. IFN exposure predominantly increased PD-L1 expression on the surface of beta cell EVs and beta cell EV PD-L1 showed a dose-dependent capacity to bind PD-1. Functional experiments demonstrated specific effects of beta cell EV PD-L1 to suppress proliferation and cytotoxicity of murine CD8 T cells. Plasma EV PD-L1 levels were increased in islet Ab+ individuals, particularly in those with single Ab+, Additionally, in from individuals with either Ab+ or type 1 diabetes, but not in controls, plasma EV PD-L1 positively correlated with circulating C-peptide, suggesting that higher EV-PD-L1 could be protective for residual beta cell function.

Conclusions/interpretation

IFN exposure increases PD-L1 on the beta cell EV surface. Beta cell EV PD-L1 binds PD1 and inhibits CD8 T cell proliferation and cytotoxicity. Circulating EV PD-L1 is higher in islet autoantibody positive patients compared to controls. Circulating EV PD-L1 levels correlate with residual C-peptide at different stages in type 1 diabetes progression. These findings suggest that EV PD-L1 could contribute to heterogeneity in type 1 diabetes progression and residual beta cell function and raise the possibility that EV PD-L1 could be exploited as a means to inhibit immune-mediated beta cell death.

Effects of phospholipid type and particle size on lipid nanoparticle distribution in vivo and in pancreatic islets

Lipid nanoparticles (LNPs) have recently been used as nanocarriers in drug delivery systems for nucleic acid drugs. Their practical applications are currently primarily limited to the liver and specific organs. However, altering the type and composition ratio of phospholipids improves their distribution in organs other than the liver, such as the spleen and lungs. This study aimed to elucidate the effects of LNP components and particle size on in vivo distribution through systemic circulation to pancreatic islets to achieve better targeting of islets, which are a fundamental therapeutic target for diabetes. Fluorescence-labeled LNPs were prepared using three phospholipids: 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), with particle sizes of 30-160 nm (diameter) using a microfluidic device. Baffled-structured iLiNP devices with adjusted flow-rate ratios and total flow rates were used. After the intravenous administration of LNPs to C57BL/6 J mice, the distribution of each LNP type to the major organs, including the pancreas and pancreatic islets, was compared using ex vivo fluorescence imaging and observation of pancreatic tissue sections. DSPC-LNPs- and DOPE-LNPs showed the highest distribution in the spleen and liver, respectively. In contrast, the DOPC-LNPs showed the highest distribution in the pancreas and the lowest distribution in the liver and spleen. In addition, smaller particles showed better distribution throughout the pancreas. The most significant LNP distribution in the islets was observed for DOPC-LNPs with a particle size of 160 nm. Furthermore, larger LNPs tended to be distributed in the islets, whereas smaller LNPs tended to be distributed in the exocrine glands. DOPC-LNPs were distributed in the islets at all cholesterol concentrations, with a high distribution observed at >40% cholesterol and > 3% PEG and the distribution was higher at 24 h than at 4 h. Thus, LNP composition and particle size significantly affected islet distribution characteristics, indicating that DOPC-LNPs may be a drug delivery system for effectively targeting the pancreas and islets.

The 60-year evolution of lipid nanoparticles for nucleic acid delivery

Delivery of genetic information to the interior of target cells in vivo has been a major challenge facing gene therapies. This barrier is now being overcome, owing in part to dramatic advances made by lipid-based systems that have led to lipid nanoparticles (LNPs) that enable delivery of nucleic acid-based vaccines and therapeutics. Examples include the clinically approved COVID-19 LNP mRNA vaccines and Onpattro (patisiran), an LNP small interfering RNA therapeutic to treat transthyretin-induced amyloidosis (hATTR). In addition, a host of promising LNP-enabled vaccines and gene therapies are in clinical development. Here, we trace this success to two streams of research conducted over the past 60 years: the discovery of the transfection properties of lipoplexes composed of positively charged cationic lipids complexed with nucleic acid cargos and the development of lipid nanoparticles using ionizable cationic lipids. The fundamental insights gained from these two streams of research offer potential delivery solutions for most forms of gene therapies.

Chemical Design Strategy of Ionizable Lipids for In Vivo mRNA Delivery

Lipid nanoparticles (LNPs) are the most clinically successful drug delivery systems that have accelerated the development of mRNA drugs and vaccines. Among various structural components of LNPs, more recent attention has been paid in ionizable lipids (ILs) that was supposed as the key component in determining the effectiveness of LNPs for in vivo mRNA delivery. ILs are typically comprised of three moieties including ionizable heads, linkers, and hydrophobic tails, which suggested that the combination of different functional groups in three moieties could produce ILs with diverse chemical structures and biological identities. In this concept article, we provide a summary of chemical design strategy for high-performing IL candidates and discuss their structure-activity relationships for shifting tissue-selective mRNA delivery. We also propose an outlook for the development of next-generation ILs, enabling the broader translation of mRNA formulated with LNPs.

Exosomes and Macrophages: Bidirectional Mutual Regulation in the Treatment of Diabetic Complications

Purpose

The bidirectional regulation of macrophages and exosomes provides a meaningful research direction for the treatment of complications arising from both type 1 and type 2 diabetes mellitus. However, there is currently no comprehensive evaluation of the bidirectional regulatory role of macrophages and exosomes in diabetic complications. In this review, we aim to provide the detailed process of the bidirectional regulation mechanism of macrophages and exosomes, and how macrophage-associated exosomes use this mechanism to make it better applied to clinical practice through biotechnology.

Methods

Therefore, we summarized the bidirectional regulation mechanism of macrophages and exosomes and the application based on the bidirectional regulation mechanism from two aspects of inflammation and insulin resistance.

Results

As key regulators of the immune system, macrophages are crucial in the progression of diabetic complications due to their significant impact on the regulation of cellular metabolism, inflammation, and insulin sensitivity. Furthermore, exosomes, as innovative mediators of intercellular communication, transport miRNAs, proteins, and various bioactive molecules, influencing the occurrence and progression of diabetic complications through the regulation of inflammation and insulin resistance. The bidirectional regulation between macrophages and exosomes provides a promising pathway for the treatment of diabetic complications aimed at regulating the immune response and improving insulin sensitivity.

Conclusions

Understanding the complexity of the interaction between macrophages and exosomes can advance the treatment of diabetic complications and drug development, and bringing more innovative and effective treatment strategies for diabetic complications.

Recent Advancements in mRNA Vaccines: From Target Selection to Delivery Systems

mRNA vaccines are leading a medical revolution. mRNA technologies utilize the host's own cells as bio-factories to produce proteins that serve as antigens. This revolutionary approach circumvents the complicated processes involved in traditional vaccine production and empowers vaccines with the ability to respond to emerging or mutated infectious diseases rapidly. Additionally, the robust cellular immune response elicited by mRNA vaccines has shown significant promise in cancer treatment. However, the inherent instability of mRNA and the complexity of tumor immunity have limited its broader application. Although the emergence of pseudouridine and ionizable cationic lipid nanoparticles (LNPs) made the clinical application of mRNA possible, there remains substantial potential for further improvement of the immunogenicity of delivered antigens and preventive or therapeutic effects of mRNA technology. Here, we review the latest advancements in mRNA vaccines, including but not limited to target selection and delivery systems. This review offers a multifaceted perspective on this rapidly evolving field.

Reformulating lipid nanoparticles for organ-targeted mRNA accumulation and translation

Fully targeted mRNA therapeutics necessitate simultaneous organ-specific accumulation and effective translation. Despite some progress, delivery systems are still unable to fully achieve this. Here, we reformulate lipid nanoparticles (LNPs) through adjustments in lipid material structures and compositions to systematically achieve the pulmonary and hepatic (respectively) targeted mRNA distribution and expression. A combinatorial library of degradable-core based ionizable cationic lipids is designed, following by optimisation of LNP compositions. Contrary to current LNP paradigms, our findings demonstrate that cholesterol and phospholipid are dispensable for LNP functionality. Specifically, cholesterol-removal addresses the persistent challenge of preventing nanoparticle accumulation in hepatic tissues. By modulating and simplifying intrinsic LNP components, concurrent mRNA accumulation and translation is achieved in the lung and liver, respectively. This targeting strategy is applicable to existing LNP systems with potential to expand the progress of precise mRNA therapy for diverse diseases.

Therapeutics of the future: Navigating the pitfalls of extracellular vesicles research from an osteoarthritis perspective

Extracellular vesicles have gained wide momentum as potential therapeutics for osteoarthritis, a highly prevalent chronic disease that still lacks an approved treatment. The membrane-bound vesicles are secreted by all cells carrying different cargos that can serve as both disease biomarkers and disease modifiers. Nonetheless, despite a significant peak in research regarding EVs as OA therapeutics, clinical implementation seems distant. In addition to scalability and standardization challenges, researchers often omit to focus on and consider the proper tropism of the vesicles, the practicality and relevance of their source, their low native therapeutic efficacy, and whether they address the disease as a whole. These considerations are necessary to better understand EVs in a clinical light and have been comprehensively discussed and ultimately summarized in this review into a conceptualized framework termed the nanodiamond concept. Future perspectives are also discussed, and alternatives are presented to address some of the challenges and concerns.