Image-based analysis of lipid nanoparticle-mediated siRNA delivery, intracellular trafficking and endosomal escape

Light-triggered nanocarriers for nucleic acid delivery

Gene therapy has evolved into a clinically viable strategy, with several approved products demonstrating its therapeutic potential for genetic disorders, cancer, and infectious diseases, and it has ample applications in regenerative medicine. Its success depends on the ability to efficiently and specifically deliver therapeutic nucleic acids (NAs) into target cells. Although viral or chemical carriers have been used in pioneering applications, safety concerns, and variable delivery efficiencies have prompted the search for alternative delivery vehicles. Light-mediated strategies have gained particular interest due to their biocompatibility and ability to improve the intracellular delivery efficiency. In this review, we focus on recent advancements in the development of light-triggered NA delivery carriers and discuss how they can be designed to overcome specific intracellular barriers. Additionally, we discuss notable therapeutic applications and highlight challenges and opportunities for translating this technology to a clinical setting.

Engineering adeno-associated viral vectors for CRISPR/Cas based in vivo therapeutic genome editing

The recent approval of the first gene editing therapy for sickle cell disease and transfusion-dependent beta-thalassemia by the U.S. Food and Drug Administration (FDA) demonstrates the immense potential of CRISPR (clustered regularly interspaced short palindromic repeats) technologies to treat patients with genetic disorders that were previously considered incurable. While significant advancements have been made with ex vivo gene editing approaches, the development of in vivo CRISPR/Cas gene editing therapies has not progressed as rapidly due to significant challenges in achieving highly efficient and specific in vivo delivery. Adeno-associated viral (AAV) vectors have shown great promise in clinical trials as vehicles for delivering therapeutic transgenes and other cargos but currently face multiple limitations for effective delivery of gene editing machineries. This review elucidates these challenges and highlights the latest engineering strategies aimed at improving the efficiency, specificity, and safety profiles of AAV-packaged CRISPR/Cas systems (AAV-CRISPR) to enhance their clinical utility.

Advances in locally administered nucleic acid therapeutics

Nucleic acid drugs represent the latest generation of precision therapeutics, holding significant promise for the treatment of a wide range of intractable diseases. Delivery technology is crucial for the clinical application of nucleic acid drugs. However, extrahepatic delivery of nucleic acid drugs remains a significant challenge. Systemic administration often fails to achieve sufficient drug enrichment in target tissues. Localized administration has emerged as the predominant approach to facilitate extrahepatic delivery. While localized administration can significantly enhance drug accumulation at the injection sites, nucleic acid drugs still face biological barriers in reaching the target lesions. This review focuses on non-viral nucleic acid drug delivery techniques utilized in local administration for the treatment of extrahepatic diseases. First, the classification of nucleic acid drugs is described. Second, the current major non-viral delivery technologies for nucleic acid drugs are discussed. Third, the bio-barriers, administration approaches, and recent research advances in the local delivery of nucleic acid drugs for treating lung, brain, eye, skin, joint, and heart-related diseases are highlighted. Finally, the challenges associated with the localized therapeutic application of nucleic acid drugs are addressed.

Design and screening of novel endosomal escape compounds that enhance functional delivery of oligonucleotides in vitro

Antisense oligonucleotides (ASOs), including splice-switching oligonucleotides (SSOs), are promising therapeutic approaches for targeting genetic defects. ASOs act in the nucleus and the cytosol to cleave mRNAs via the RNaseH1 mechanism (e.g., gapmers), while SSOs alter transcript splicing to restore or inhibit protein function. RNA interference (RNAi) is another approach to down-regulate gene expression via the RISC complex. However, a major challenge is the effective delivery of these nucleic acid-based therapeutics. Recent developments focus on enhancing cellular uptake and endosomal release, including the use of small-molecule endosomal escape enhancers (EEEs) such as chloroquine. Here, we disclose a next generation of EEEs, which efficiently enhance SSOs and gapmers in vitro activity. We identify proton sponge-mediated endosomal leakage as a mechanism of action and observe, by Gene Ontology analysis on bulk RNA sequencing, that EEE treatment increased gene expression of markers associated with vesicle organization. Additionally, using primary human hepatocytes, we demonstrate that EEEs enhance small interfering RNA (siRNA) activity. Unconjugated siRNA reached similar levels of mRNA knockdown to the observed GalNAc-conjugated siRNA. Substantial GalNAc conjugated siRNA enhancement was also observed when used together with EEE. Our results indicate that these EEEs constitute a promising strategy to enhance the activity of multimodal oligonucleotide therapeutics.

ATP-responsive tumor targeted lipid nanoparticle for enhanced siRNA delivery and improved treatment efficacy in melanoma

Small interfering RNA (siRNA) plays a crucial role in tumor therapy, especially for non-druggable targets with obvious advantages. Nevertheless, its molecular weight, negative charge, and susceptibility to degradation hinder effective delivery to tumor cells for therapeutic action. Lipid nanoparticles (LNPs) serve as an excellent delivery mechanism for siRNA but still face problems such as suboptimal tumor targeting and inefficient intracellular release. To enhance melanoma treatment, we designed lipid nanoparticles modified with phenylboronic acid (PBA) for efficient delivery of siRNA targeting "undruggable" microphthalmia-associated transcription factor (MITF). This nanocarrier successfully encapsulated siRNA and improved tumor targeting by allowing phenylboronic acid to interact with sialic acid residues overexpressed in tumor cells. Furthermore, PBA-modified lipid nanoparticles facilitated the ATP-responsive release of siRNA intracellular. These two aspects enhance gene silencing efficiency. The in vivo targeting and gene silencing capabilities of PBA-modified lipid nanoparticles significantly surpassed those of unmodified LNP. Additionally, PBA-modified nanoparticles exhibited considerable anti-tumor and anti-metastatic effects in animal models, offering an alternative approach for siRNA therapy.

Intracellular processing of DNA-lipid nanoparticles: A quantitative assessment by image segmentation

Carriers for efficient delivery of nucleic acids, such as lipid nanoparticles (LNPs), have gained much attention for gene therapy applications. Intracellular processing of such nanocarriers is a complex mechanism comprising cellular internalization by endocytosis pathways, endosomal release into the cytosol, lysosomal degradation, and recycling. The endosomal escape rates of current formulations are considered low, and methods to reliably quantify endocytic events are not readily available. To address this shortcoming and to support the optimization of LNP formulations, the current study presents an automated live-cell imaging-based analysis method. Engineered HuH7 hepatic cell lines overexpressing fluorescent Galectin and Rab reporters together with lysosomal co-staining enabled qualitative and quantitative tracking of DNA-loaded LNPs. The use of two fluorescently labeled DNA-LNP formulations containing either SM-102 or ALC-0315 ionizable lipids revealed significant differences in endosomal escape rates and intracellular processing. Upon treatment, only subpopulations of the HuH7 target cells could be activated with respect to escape or recycling. Recycling inhibitors were therefore used to promote endosomal escape. These findings provide valuable insights into the timing and regulation of endocytic events, which will be instrumental to optimize therapeutic LNP formulations.

Mechanistic intracellular PK/PD modeling to inform development strategies for small interfering RNA therapeutics

Small interfering RNA (siRNA) therapeutics provide a targeted approach to silence disease-related genes, with notable success in liver-targeting applications. However, the quantitative effects of siRNA properties, such as stability and affinity, as well as biological factors like cell proliferation, mRNA turnover, and abundance, on gene silencing, particularly for extrahepatic targets, remain poorly understood. To identify determinants influencing gene knockdown extent and duration, we developed a mechanistic intracellular pharmacokinetic/pharmacodynamic (PK/PD) model for RNAiMAX-delivered siRNA, based on cytoplasmic siRNA disposition, RISC-loaded siRNA exposure, and mRNA knockdown across different targets in MCF7 and BT474 cells. The model highlighted the critical roles of cell proliferation in silencing duration and mRNA turnover rates on knockdown extent. In rapid-dividing cells, mRNA half-life drives knockdown profiles, whereas chemical siRNA stabilization extends silencing in slow-dividing cells. Targets with extremely low or high mRNA abundance pose silencing challenges. While sufficient RISC occupancy is essential, increasing RISC exposure has minimal impact on silencing extent; enhancing siRNA-mRNA target engagement is more effective. The model also defined a quantitative relationship for maximal mRNA knockdown, governed by cell proliferation, mRNA half-life, and RISC-mediated cleavage rates. This mechanistic PK/PD modeling provides insights into optimizing siRNA design and target selection in therapeutic development.

Poly-lysine-modified recombinant protein nanocages for effective delivery of small activating RNA

Small activating RNA (saRNA) holds significant promise as a therapeutic platform for various diseases. However, the development of efficient nanocarriers that can overcome existing delivery challenges and ensure effective cellular uptake remains a critical hurdle. In this study, we aimed to address this issue by genetically modifying four lysine residues at the N-terminus of the FTH gene through gene recombinant technology, resulting in the creation of poly-lysine-H-apoferrin (4LF) vectors. These vectors were designed to efficiently deliver saRNA encoding the Sirtuin1 (Sirt1) protein to chondrocytes, thereby mitigating cartilage damage. The poly-lysine modification conferred the ability of 4LF@saRNA nanoparticles (NPs) to escape from lysosomes via proton sponge effects and to release saRNA into the cytoplasm through the pH-induced degradation of the 4LF vector, ultimately activating the target gene. To enhance the retention of NPs within the joint cavity and facilitate intra-articular delivery, we incorporated the 4LF@saRNA NPs into a thermosensitive self-healing hydrogel composed of chitosan, oxidized chondroitin sulfate (OCS), and sodium β-glycerophosphate (β-GP). Experimental results demonstrated that the chitosan/OCS/β-GP-4LF@saRNA (OCCG-4LF@saRNA) delivery system effectively delivered the 4LF@saRNA NPs to chondrocytes both in vitro and in vivo, resulting in a significant increase in Sirt1 protein expression. This upregulation led to a reduction in chondrocyte apoptosis, enhanced cell migration, and improved cartilage protection, effectively alleviating symptoms of osteoarthritis. In conclusion, our findings suggested that the 4LF-based delivery system hold considerable potential for effective intracellular saRNA delivery, demonstrating promising biocompatibility, stability, and delivery efficiency, with significant therapeutic implications for cartilage repair.

Autonomic lysosomal escape via sialic acid modification enhances mRNA lipid nanoparticles to eradicate tumors and build humoral immune memory

Lysosomes present a major barrier to efficient mRNA delivery. Existing strategies primarily depend on lysosomal disruption, which is inefficient and carries a risk of cytolysis. We propose an Autonomic Lysosomal Escape (ALE) strategy, in which sialic acid (SA) modification enables over 90 % of LNPs to successfully escape from lysosomes by inducing cells to spontaneously reduce lysosome generation. The SA modification enhances the transfection efficiency of LNPs administered via intravenous injection, intramuscular injection, and inhalation, demonstrating the broad applicability. The structure of cleavable PEG-lipids was optimized using a newly developed method, termed Systematic Evaluation of LNPs' Efficiency by Cumulative Tests (SELECT). The results showed that polyethylene glycol 2000-cholesterol hemisuccinate (Ps) is the optimal candidate for co-modification with SA. The resulting LNPs co-modified with SA and Ps (SAPs@LNPs) completely eradicated TC-1 tumors and induced humoral immune memory. Combining SA-modified doxorubicin liposomes (DOX-SL) further accelerates tumor elimination, while licensed PEGylated liposomal doxorubicin (Caelyx) impairs the efficacy of mRNA vaccines. This difference stems from DOX-SL's selective depletion of tumor-associated immune cells (TAICs) and the nonspecific cytotoxicity of Caelyx. These findings suggest that combining Caelyx with mRNA vaccines should be approached with caution. Our study also highlights the key roles of humoral immune memory and natural killer cell-driven antibody-dependent cellular cytotoxicity (ADCC) in tumor eradication, and incorporating them into the cancer immune cycle further refines this theory.

Multiparametric functional characterization of individual lipid nanoparticles using surface-sensitive light-scattering microscopy

The most efficient lipid nanoparticles (LNPs) for gene therapeutics rely on specific lipids that protect the oligonucleotide cargo and aid cellular uptake and subsequent endosomal escape. Yet, the efficacy of current state-of-the-art LNP formulations remains low, a few percent at best. A deeper understanding of how LNP cargo, lipid composition, stoichiometry, size, structure, and pH-induced conformational changes influence their efficiency is therefore necessary for improved design. Given the variability of these properties, preferred screening methods should offer single-particle-resolved multiparametric characterization. In this work, we employ combined surface-sensitive fluorescence and label-free scattering microscopy with single LNP resolution, which when integrated with microfluidics for liquid exchange between media of varying refractive index, enables quantification of LNP size, refractive index, and cargo content. We investigate two LNP formulations that, while similar in size and mRNA content, exhibit differences in functional mRNA delivery. Correlating size with the content of Cy5-labeled mRNA revealed that the cargo scaled with LNP volume for both types of LNPs, while the refractive index varied marginally across LNP size. While this multiparametric fingerprinting alone could not distinguish the two LNP formulations, we use the same experimental platform to show that their difference in fusogenicity to a supporting lipid bilayer under early endosomal conditions (drop in pH from 7.4 to 6.0) correlates with observed differences in in vitro cellular data. This highlights a limitation of the current state-of-the-art toolbox for in situ LNP characterization, which generally focuses on structural properties of suspended LNPs, which may not adequately capture functional performance.

DNA Origami-Based CD44-Targeted Therapy Silences Stat3 Enhances Cartilage Regeneration and Alleviates Osteoarthritis Progression

Osteoarthritis (OA) is a widespread musculoskeletal disorder affecting ≈600 million people globally, and small interfering RNA (siRNA) therapy shows potential in targeting OA progression. However, the efficient and targeted delivery of siRNA remains a major challenge due to issues with tissue specificity and degradation in vivo. In this study, A DNA origami-based chondrocyte-targeted delivery system (OCS) is designed for siRNA delivery to OA-affected cartilage. The DNA origami is engineered to load with siRNA targeting signal transducer and activator of transcription 3 (Stat3), a key regulator of inflammation and cartilage degradation, and is functionalized with anti-CD44 aptamers for selective targeting of OA chondrocytes. In vitro, the DNA origami system effectively delivers siRNA to diseased chondrocytes, silencing matrix metalloproteinases expression and reducing inflammation. In OA rat models, it preserves cartilage integrity, promotes regeneration, and mitigates ECM degradation without evident side effects. These findings highlight DNA origami as a promising platform for siRNA-based OA therapy, offering a promising solution to the challenges of targeted and efficient siRNA delivery.

The Internal Nanostructure of Lipid Nanoparticles Influences Their Diverse Cellular Uptake Pathways

Lipid nanoparticles have emerged as critical platforms for bioactive agent delivery, with their success in COVID-19 vaccines highlighting the urgent need to address gaps in understanding their biological interactions. Lyotropic liquid crystalline nanoparticles (LLCNPs) represent promising nanocarriers for bioactive agent delivery. In this study, it is revealed for the first time how internal nanostructures of LLCNPs - liposomes, cubosomes, hexosomes, and micellar cubosomes - influence their cellular uptake pathways. By isolating the effects of mesophase while maintaining consistent particle size, charge, and surface coating, it is demonstrated that non-lamellar LLCNPs, particularly cubosomes, significantly enhance cellular uptake via distinct endocytic and non-endocytic mechanisms. These nanoparticles predominantly utilize passive non-endocytic pathways, such as membrane fusion, bypassing endocytic recycling challenges faced by most nanomaterials, including lamellar liposomes. Among active endocytic pathways, macropinocytosis emerges as the dominant route for non-lamellar particles. The findings establish a direct link between LLCNP internal nanostructure and cellular internalization mechanisms, highlighting the critical role of mesophase design in optimizing nanocarrier performance. This knowledge enables the rational engineering of LLCNPs tailored to target specific uptake pathways, facilitating precision delivery for diverse therapeutic applications and addressing key barriers in intracellular drug transport.

Engineered multi-domain lipid nanoparticles for targeted delivery

Engineered lipid nanoparticles (LNPs) represent a breakthrough in targeted drug delivery, enabling precise spatiotemporal control essential to treat complex diseases such as cancer and genetic disorders. However, the complexity of the delivery process-spanning diverse targeting strategies and biological barriers-poses significant challenges to optimizing their design. To address these, this review introduces a multi-domain framework that dissects LNPs into four domains: structure, surface, payload, and environment. Engineering challenges, functional mechanisms, and characterization strategies are analyzed across each domain, along with a discussion of advantages, limitations, and in vivo fate (e.g., biodistribution and clearance). The framework also facilitates comparisons with natural exosomes and exploration of alternative administration routes, such as intranasal and intraocular delivery. We highlight current characterization techniques, such as cryo-TEM and multiscale molecular dynamics simulations, as well as the recently emerging artificial intelligence (AI) applications-ranging from LNP structure screening to the prospective use of generative models for de novo design beyond traditional experimental and simulation paradigms. Finally, we examine how engineered LNPs integrate active, passive, endogenous, and stimuli-responsive targeting mechanisms to achieve programmable delivery, potentially surpassing biological sophistication in therapeutic performance.

Recent Advances in mRNA Delivery Systems for Cancer Therapy

mRNA therapy is a promising approach in oncology, offering innovative applications such as tumor vaccines, protein replacement therapy, cell therapy, and gene therapy. However, challenges such as mRNA stability and delivery efficiency must be addressed. Advances in delivery system technologies are crucial for precise mRNA delivery, enhancing treatment safety and efficacy. The development of delivery systems requires accurate organ or cell targeting, intelligent release mechanisms, and optimized administration routes. This review outlines the applications of mRNA therapy in oncology, as well as the utilization of nonviral vectors, encompassing organic, inorganic, and biomimetic systems. It further elucidates the strategies for passive and active vector targeting and examines recent advances in the realm of stimuli-responsive delivery systems that are sensitive to pH and ultrasound. Additionally, the review addresses the development of noninvasive mRNA delivery systems designed for oral and pulmonary administration. The current challenges and emerging trends of mRNA therapy are discussed, and the potential strategies to mitigate these issues are emphasized.

Tailoring diblock copolymers for efficient siPLK1 delivery and enhanced gene therapy of orthotopic osteosarcoma

Osteosarcoma (OS) is a primary malignant bone tumor characterized by its aggressive local destruction and high metastatic potential. RNA interference (RNAi)-based therapeutics show great promise for treating OS; yet the challenge lies in developing safe and efficient delivery systems that can achieve effective siRNA delivery and therapeutic outcomes, particularly in orthotopic OS models. Herein, we introduce a diblock copolymer with precisely designed block composition and length that simultaneously fulfills the multiple requirements for siRNA delivery, both in vitro and in vivo. We selected siPLK1 as the active RNA and defined the copolymer as PEG113-b-P(AAPBA20-co-DMAPMA20), containing boronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units. Both AAPBA and DMAPMA can bind to siRNA, but only their random combination with appropriate block length formed well-defined NPs that facilitated efficient endocytosis. Adequate endosomal escape and siRNA release were then achieved through the cationic PAM and responsive PBA units, respectively. The shielding PEG block, further modified with an alendronate sodium (AS) moiety, enabled OS-targeted delivery of siPLK1. The designed copolymer achieved 83.9% in vitro PLK1 gene silencing, outperforming Lipo3000 (49.3%), and demonstrated superior anti-tumor (74.6% inhibition rate) and anti-metastasis effects in a highly metastatic orthotopic 143B OS model.

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.

Dissolving microneedles for nucleic acid delivery: A systematic search, review, and data synthesis

Dissolving microneedles deliver many classes of nucleic acids, overcoming susceptibility to enzymatic cleavage and poor intracellular delivery. Understanding the impact of microneedle formulation on nucleic acid therapeutic efficacy is critical for clinical translation. Here, we performed a systematic search to identify preclinical dissolving microneedle studies that deliver nucleic acid therapeutics including aptamers, DNA enzymes, mRNA, miRNA, plasmid DNA, recombinant viral vectors, and siRNA. This review quantitatively synthesizes preclinical data to identify correlations between microneedle form and function. Factors such as polymer molecular weight and incorporation of a nucleic acid carrier strongly influence mechanical and biological properties, while other design parameters allow for more flexibility. Altogether, 83 % of studies show equivalent or superior efficacy to existing nucleic acid administration routes including topical, subcutaneous, and intramuscular administration. Data especially supports the use of dissolving microneedles for viral and cancer vaccine applications, with a growing body of work exploring their utility for gene silencing. Nonetheless, several knowledge gaps remain. Emerging nucleic acid carrier chemistries that retain efficacy with improved toxicity profiles will define the next generation of formulations. Plasmid DNA and viral vectors show excellent long-term stability in dissolving microneedles, but further characterization is needed for long RNA transcripts. Finally, future work could explore the potential for non-dermal administration routes, as well as co-delivery of nucleic acids with small molecules to leverage synergistic effects. STATEMENT OF SIGNIFICANCE: This review comprehensively, critically, and quantitatively synthesizes preclinical dissolving microneedles for nucleic acid delivery. This approach identifies empirically supported correlations between microneedle form and function, highlighting evidence-based best practices and remaining challenges. The form-function relationships identified in this review will be valuable to those within the immediate microneedle field, as well as more broadly to audiences interested in nucleic acid therapeutics, drug delivery systems, microfabrication, and delivery strategies for low resource settings.

Structure-guided design of endosomolytic chloroquine-like lipid nanoparticles for mRNA delivery and genome editing

Despite remarkable progress in designing RNA delivery systems, endosomal escape remains a recognized challenge for efficient RNA delivery. In this study, we develop a robust mRNA delivery platform termed endosomolytic chloroquine-like optimized lipid nanoparticles (ecoLNPs) for versatile mRNA delivery in vitro and in vivo via integrating the signature scaffold extracted from endosomolytic chloroquine into ionizable lipids. RNase-resistant ecoLNPs are capable of delivering a broad variety of mRNA payloads to diverse cell types, even hard-to-transfect 3D cells, with an efficiency of up to 18.9-fold higher than that of commercial transfection reagents. The pH-responsive endosomolytic activity of ecoLNPs can be largely attributed to the proton sponge effect and saposin B-promoted membrane disruption. In vivo, ecoLNPs enable potent local and systemic mRNA delivery and exhibit comparable potency to the clinically approved mRNA vaccine carrier, but strong tropism for lymph nodes following intramuscular injection. Furthermore, ecoLNPs are able to retain in vivo delivery potency for at least one week under non-frozen conditions and induce efficient genome editing in transgenic mice. Overall, the structure-guided integration strategy provides a pathway for de novo design of endosomolytic mRNA delivery systems.

Topologically Engineered Supramolecular Cyclolipid Nanoparticles: A Custom-Tailored Delivery System for Inhaled Combination Therapy

Lipid nanoparticles (LNPs) have shown promising potential in the development of nucleic acid therapeutics and vaccines; however, unsatisfactory endosomal escape efficiency and physiological stability hinder their clinical applications. Herein, we design and synthesize a novel topologically engineered cyclodextrin-cored lipid (cyclolipid) featuring seven tertiary amine groups, seven secondary amine groups, and 14 hydrophobic alkyl tails to fabricate two-component supramolecular cyclolipid nanoparticles (CNPs). Benefiting from its cone-shaped structure, the cyclolipid facilitates the transition of endosomal membranes from the lamellar phase to the unstable hexagonal II phase, thereby promoting membrane destabilization and endosomal escape of CNPs. Additionally, the high density of ionizable sites enhances the binding capacity with RNA, while multiple hydrophobic alkyl chains strengthen the stability of CNPs, thus guaranteeing the in vivo circulation stability. Interestingly, the cavity of the cyclolipid enables the encapsulation of pirfenidone (PFD, an antifibrotic drug) through host-guest interactions, offering a promising strategy for synergistic therapy. Rationally optimizing the components and physicochemical properties of CNPs dramatically promotes mucus penetration capability, thereby enhancing their bioavailability in the lungs and avoiding unwanted side effects toward other organs. Leveraging their exceptional ability for achieving physiological stability, mucus penetration, and endosomal escape, siRNA targeting heat shock protein 47 (siHsp47) and PFD are codelivered by CNPs (CNPs@siHsp47/PFD) for the treatment of pulmonary fibrosis. CNPs@siHsp47/PFD synergistically alleviates pulmonary fibrosis, achieving therapeutic outcomes comparable to those of healthy mice, highlighting the outstanding potential of CNPs as the next-generation delivery platform for drug and gene combination therapy.

Modulating the Protein Corona on Nanoparticles by Finely Tuning Cross-Linkers Improves Macrophage Targeting in Oral Small Interfering RNA Delivery

The protein corona (PC) plays an important role in regulating the in vivo fate of nanoparticles (NPs). Modulating the surface chemical properties of NPs to control PC formation provides an alternative impetus for the oral delivery of small interfering RNA (siRNA). Herein, using tripolyphosphate (TPP), hyaluronic acid, and poly-γ-glutamic acid as cross-linkers, three types of mannose-modified trimethyl chitosan-cysteine (MTC)-based NPs with distinct surface chemistries were prepared to encapsulate siRNA via ionic gelation. The MTC-based NPs that were cross-linked exclusively with TPP (MTC/TPP/siRNA NPs) exhibited greater thiol group accessibility on their surfaces, resulting in a stronger affinity for apolipoprotein (APO) B48 during translocation across intestinal epithelia. Moreover, intracellular transport of MTC/TPP/siRNA NPs via the endoplasmic reticulum and Golgi apparatus further increased adsorption of APOB48, a key component of chylomicrons, which follow a similar transport pathway. Benefiting from the elevated APOB48 levels within the PC, the orally delivered MTC/TPP/siRNA NPs showed higher uptake by hepatic macrophages and better therapeutic efficacy for acute liver injury. Our results elucidate the role of NP surface chemical characteristics and translocation mechanisms across intestinal epithelia in forming oral PC, providing valuable insights for designing NPs that achieve effective oral gene delivery by customizing PC formation in vivo.

Prediction of Interspecies Translation for Targeting Delivery Coefficients of GalNAc-siRNA Silencing Apolipoprotein C-III Using a Mechanistic Minimal Physiologically Based Pharmacokinetic/Pharmacodynamic Model

BACKGROUND AND OBJECTIVE

The emerging N-acetylgalactosamine-small interfering RNA (GalNAc-siRNA) conjugates lead the way for liver-targeting delivery to exert gene-silencing therapeutic effects. To facilitate the drug development of GalNAc-siRNA, further detailed understanding of the key modality-specific mechanisms underlying the temporal discordance between pharmacokinetics and pharmacodynamics and how these processes can be extrapolated from animals to humans is needed.

METHODS

A mechanistic minimal physiologically based pharmacokinetic/pharmacodynamic (mPBPK-PD) model for an investigational new apolipoprotein C-III (APOC3)-silencing GalNAc-siRNA (RBD5044) was developed using available pharmacokinetic/pharmacodynamic (PK/PD) data. The aim was to explore hepatic-targeting delivery processes, the PK/PD relationship, and interspecies translation.

RESULTS

First, multiple PK/PD datasets from mice were satisfactorily fitted using the mPBPK-PD model. Second, we translated the mice model to the monkey model, validated it, and then extrapolated from mice and monkeys to humans to simulate the PK/PD characteristics. We then mechanistically summarized and proposed the essential in vivo delivery processes of GalNAc-siRNA after subcutaneous administration (termed "ADUEB": Absorption [into system circulation], Disposition [distribution to liver target and elimination], Uptake [into hepatocytes], Escape [from endosome and lysosome compartments], and Binding [with argonaute2 to form RNA-induced silencing complex]). The targeting delivery coefficients of these processes achieved with the model using RBD5044 and the published data of another GalNAc-siRNA (fitusiran) quantitatively reflected the delivery efficiency and rate-limiting factors in targeted hepatocytes.

CONCLUSION

This study successfully constructed the mPBPK-PD model and conducted interspecies extrapolation for a GalNAc-siRNA targeting APOC3. Promising quantitative insights into a hepatic-targeted GalNAc-siRNA delivery system are provided to characterize the unique temporal disconnection of PK/PD properties and evaluate the key in vivo delivery processes. It will promote model-informed strategies and quantitative mechanistic understanding to support efficient drug development, evaluation, and clinical application of this modality in the future.

Cubic Phase-Inducible Zwitterionic Phospholipids Improve the Functional Delivery of mRNA

Lipid nanoparticles (LNPs) are clinically advanced delivery systems for RNA. The extensively developed structure of ionizable lipids greatly contributes to the functional delivery of mRNA. However, endosomal escape is one of the severe biological barriers that continue to render this process inefficient (e.g., less than 10%). Although LNPs contain phospholipids, their role is poorly understood, and there have been few attempts to perform the chemical engineering required to improve their functionality. Herein, a cubic phase-inducible fusogenic zwitterionic phospholipid derived from 1,2-dioleoyl-3-sn-glycero-phosphoethanolamine (DOPE), DOPE-Cx is described, that is designed to correct this problem. The orientation of a zwitterionic head group of DOPE is engineered by attaching a series of hydrophobic moieties for zwitterionic intermolecular interaction with the head structure of phosphatidylcholine (PC), and this is followed by a lipid-phase transition into non-lamellar phases to facilitate membrane fusion-mediated endosomal escape. A structure-activity relationship study reveals that DOPE-Cx lipids with small hydrophobic chains induce cubic phases instead of a hexagonal phase when mixed with PC, which enhances the functional delivery of mRNA in the liver as opposed to the action of the typically utilized and naturally occurring phospholipids. Engineered functionalized phospholipids will be of great value for the therapeutic applications of mRNAs.

Achieving Precision Phototherapy from Start to Finish: Integrating Endosomal Escape, Respiration Inhibition, and ROS Release in a Single Upconversion Nanoparticle

Precision phototherapy requires tight control over several therapeutic steps, which traditional methods often struggle to achieve. Here, this study reports an orthogonal trichromatic upconversion nanoparticle with a rather simple nanoarchitecture, NaErF4@NaYbF4@NaYbF4:Nd@NaYF4:Yb,Tm. Unlike conventional designs that rely on multiple activators and complicated multi-shelled structures (up to six nanoshells), the reported triple-shelled UCNPs utilize only two activator ions (Er3⁺ and Tm3⁺) but still enables to release red, green, and blue colors in response to three different NIR light excitations, thus significantly reducing structural complexity and synthetic workload. Integrating these UCNPs with photosensitizers and nitric oxide (NO) donors further achieve to a precision photodynamic therapy, which allows for step-wise control throughout the entire PDT process by independent activation of bioimaging, photochemical internalization, respiration prohibition via NO release, and ROS generation via specific light illuminations. Both in vitro and in vivo results demonstrate high efficiency of presented methodology, highlighting its great potential for NIR light-activated precision phototherapy.

Recent strategies for enhanced delivery of mRNA to the lungs

mRNA-based therapies have emerged as a transformative tool in modern medicine, gaining significant attention following their successful use in COVID-19 vaccines. Delivery to the lungs offers several compelling advantages for mRNA delivery. The lungs are one of the most vascularized organs in the body, which provides an extensive surface area that can facilitate efficient drug transport. Local delivery to the lungs bypasses gastrointestinal degradation, potentially enhancing therapeutic efficacy. In addition, the extensive capillary network of the lungs provides an ideal target for systemic delivery. However, developing effective mRNA therapies for the lungs presents significant challenges. The complex anatomy of the lungs and the body's immune response to foreign particles create barriers to delivery. This review discusses key approaches for overcoming these challenges and improving mRNA delivery to the lungs. It examines both local and systemic delivery strategies aimed at improving lung delivery while mitigating off-target effects. Although substantial progress has been made in lung-targeted mRNA therapies, challenges remain in optimizing cellular uptake and achieving therapeutic efficacy within pulmonary tissues. The continued refinement of delivery strategies that enhance lung-specific targeting while minimizing degradation is critical for the clinical success of mRNA-based pulmonary therapies.

Tumor-Selective Gene Therapy: Using Hairpin DNA Oligonucleotides to Trigger Cleavage of Target RNA by Endogenous flap endonuclease 1 (FEN 1) Highly Expressed in Tumor Cells

Nucleic acid drugs, which trigger gene silencing by hybridizing with target genes, have shown great potential in targeting those undruggable targets. However, most of the existing nucleic acid drugs are only sequence specific for target genes and lack cellular or tissue selectivity, which challenges their therapeutic safety. Here, the study proposes a tumor cell-specific gene silencing strategy by using hairpin DNA oligonucleotides to trigger target RNA degrading by highly expressed endogenous flap endonuclease 1 (FEN1) in tumor cells, for selective tumor therapy. Using Kirsten rat sarcoma viral oncogene homolog (KRASG12S) and B-cell lymphoma 2 (Bcl-2) genes as targets, it is verified that the hairpin DNA oligonucleotides show cytotoxicity only to tumor cells but very low effects on normal cells. In addition, hairpin DNA oligonucleotides designed for KRAS inhibition, which are encapsulated in lipid nanoparticles, inhibit tumor growth in mice and demonstrate excellent antitumor efficacy in combination with gefitinib, but has little effect on normal tissues, suggesting that the proposed strategy enables highly selective tumor therapy and has the potential to give rise to a new class of nucleic acid drugs.

Highly Branched Poly(β-amino ester)s for Efficient mRNA Delivery and Nebulization Treatment of Silicosis

mRNA therapeutics hold tremendous promise for disease prevention and treatment. Development of high-performance mRNA delivery systems with enhanced transfection efficiency and a safety profile will further fulfill their therapeutic potential and expedite their translation. The synthesis of "four-in-one" highly branched poly(β-amino ester)s (O-LhPAEs) is reported by integrating the essential components of lipid nanoparticles (LNPs) for spleen-selective mRNA enrichment and nebulization treatment of silicosis. 60 O-LhPAEs with distinct branched structure and chemical composition, including tertiary/quaternary amines, cholesterol moieties, zwitterionic species, and hydrophobic alkyl tails, are synthesized using sequential Michael addition, ring-opening, and nucleophilic substitution reactions. The unique topological structure and chemical composition collectively enhanced O-LhPAEs/mRNA polyplex serum resistance, cellular uptake, and endosomal escape. The optimal O-LhPAE, 20%b-3C-2P12, exhibits up to 93.1% mRNA transfection across 11 different cell types, including epithelial cells, fibroblasts, cancer cells, stem cells, neurological cells, and astrocytes. Biodistribution study reveals that 20%b-3C-2P12/mRNA polyplexes are mainly enriched in the spleen following systemic administration. Through nebulization, 20%b-3C-2P12 mediated high Tbx2 mRNA expression in the lungs of silicosis mice, effectively restoring lung functions. This study not only establishes a strategy for development of LNP-like O-LhPAEs but also provides promising candidates for highly safe, efficient, and spleen-selective mRNA delivery and nebulization treatment of silicosis.

Engineering of extracellular vesicles for efficient intracellular delivery of multimodal therapeutics including genome editors

Intracellular delivery of protein and RNA therapeutics represents a major challenge. Here, we develop highly potent engineered extracellular vesicles (EVs) by incorporating bio-inspired attributes required for effective delivery. These comprise an engineered mini-intein protein with self-cleavage activity for active cargo loading and release, and fusogenic VSV-G protein for endosomal escape. Combining these components allows high efficiency recombination and genome editing in vitro following EV-mediated delivery of Cre recombinase and Cas9/sgRNA RNP cargoes, respectively. In vivo, infusion of a single dose Cre loaded EVs into the lateral ventricle in brain of Cre-LoxP R26-LSL-tdTomato reporter mice results in greater than 40% and 30% recombined cells in hippocampus and cortex respectively. In addition, we demonstrate therapeutic potential of this platform by showing inhibition of LPS-induced systemic inflammation via delivery of a super-repressor of NF-ĸB activity. Our data establish these engineered EVs as a platform for effective delivery of multimodal therapeutic cargoes, including for efficient genome editing.

Extracellular membrane particles en route to the nucleus - exploring the VOR complex

Intercellular communication is an essential hallmark of multicellular organisms for their development and adult tissue homeostasis. Over the past two decades, attention has been focused on communication mechanisms based on various membrane structures, as illustrated by the burst of scientific literature in the field of extracellular vesicles (EVs). These lipid bilayer-bound nano- or microparticles, as vehicle-like devices, act as regulators in various biological and physiological processes. When EVs are internalized by recipient cells, their membrane and cytoplasmic cargoes can interfere with cellular activities, affecting pathways that regulate cell proliferation, differentiation, and migration. In cancer, EVs can transfer oncogenic factors, stimulate neo-angiogenesis and immunosuppression, reprogram stromal cells, and confer drug resistance traits, thereby remodeling the surrounding microenvironment. Although the mechanisms underlying EV biogenesis and uptake are now better understood, little is known about the spatiotemporal mechanism(s) of their actions after internalization. In this respect, we have shown that a fraction of endocytosed EVs reaches the nuclear compartment via the VOR (VAP-A-ORP3-Rab7) complex-mediated docking of late endosomes to the outer nuclear membrane in the nucleoplasmic reticulum, positioning and facilitating the transfer of EV cargoes into the nucleoplasm via nuclear pores. Here, we highlight the EV heterogeneity, the cellular pathways governing EV release and uptake by donor and recipient cells, respectively, and focus on a novel intracellular pathway leading to the nuclear transfer of EV cargoes. We will discuss how to intercept it, which could open up new avenues for clinical applications in which EVs and other small extracellular particles (e.g., retroviruses) are implicated.

Unleashing the power of nucleic acid therapeutics through efficient cytosolic delivery

The approval of siRNA-based therapy for liver disease in 2018 and the subsequent success of mRNA-based SARS-CoV-2 vaccines have inaugurated a new era in nucleic acid-based therapeutics. These breakthroughs underscore the transformative potential of nucleic acid-based therapeutics, which modulate gene function, correct genetic defects, or disrupt pathological molecular processes. Such advances represent a paradigm shift in modern medicine. Despite their immense promise, the clinical realization of nucleic acid-based therapies is fundamentally constrained by endosomal entrapment, a critical barrier that significantly limits therapeutic efficacy. Overcoming this obstacle is imperative to fully unlock the potential of these therapies. Designing effective strategies to facilitate the escape of nucleic acids from endosomes-or bypassing endosomal pathways altogether-remains a central challenge in the field. In this review, we provide a comprehensive and critical analysis of current approaches aimed at enhancing endosomal escape or circumventing endosomal entrapment. By highlighting both the successes and limitations of these strategies, we aim to offer valuable insights to inform the development of more efficient and clinically viable nucleic acid delivery systems, advancing the future of molecular medicine.

Lipid nanoparticles with prazole adjuvant to enhance the efficacy of mRNA cancer vaccines

Although Food and Drug Administration (FDA)-approved lipid nanoparticles (LNPs) exhibit reliable efficiency in mRNA delivery, they still encounter certain challenges owing to biological barriers. Specifically, LNPs have poor cytoplasmic release owing to endo-/lysosomal barriers. Additionally, extracellular barriers such as the extracellular matrix (ECM) hinder particle movement and reduce cellular uptake efficiency. In this study, we developed newly designed formulations using a combination of LNPs and esomeprazole (ESO) as an adjuvant to improve mRNA cytoplasmic release and enhance particle dynamics within the ECM in vivo. The ESO-containing LNP formulation increased endo-/lysosomal pH, resulting in reduced membrane integrity and facilitating the escape of mRNA from the endo-/lysosomes. Additionally, this formulation modulated fibroblast activity through the TGF-β signaling pathway, which altered the ECM composition and enhanced LNP and mRNA penetration into cellular spheroids. Our results demonstrated that the LNP formulation combined with ESO improved mRNA antigen expression both in vitro and in vivo. Notably, the increased mRNA antigen expression induced by the ESO-containing formulation successfully stimulated immune responses, resulting in the activation of dendritic -, CD4+ T -, and CD8+ T cells. Furthermore, this formulation elicited robust antigen-specific immune responses, including an elevation in antigen-specific CD8+ T cells and a significant increase in antigen-specific IgG levels. The enhanced immune response resulting from the combined formulation during vaccination enabled prolonged and strengthened protection against melanoma. Thus, these newly designed formulations combining ESO and LNPs offer significant value and represent a promising strategy for mRNA-based therapeutic applications.

Hurdles to healing: Overcoming cellular barriers for viral and nonviral gene therapy

Gene delivery offers great potential for treating various diseases, yet its success requires overcoming several biological barriers. These hurdles span from extracellular degradation, reaching the target cells, and inefficient cellular uptake to endosomal entrapment, cytoplasmic transport, nuclear entry, and transcription limitations. Viruses and non-viral vectors deal with these barriers via different mechanisms. Viral vectors, such as adenoviruses, adeno-associated viruses, and lentiviruses use natural mechanisms to efficiently deliver genetic material but face limitations including immunogenicity, cargo capacity, and production complexity. Nonviral vectors, including lipid nanoparticles, polymers, and protein-based systems, offer scalable and safer alternatives but often fall short in overcoming intracellular barriers and achieving high transfection efficiencies. Recent advancements in vector engineering have partially overcome several of these challenges. Ionizable lipids improve endosomal escape while minimizing toxicity. Biodegradable polymers balance efficacy with safety, and engineered protein systems, inspired by viral or bacterial entry mechanisms, integrate multifunctionality for enhanced delivery. Despite these advances, challenges, particularly in achieving robust in vivo translatability, scalability, and reduced immunogenicity, remain. This review synthesizes current knowledge of cellular barriers and the approaches to overcome them, providing a roadmap for designing more efficient gene delivery systems. By addressing these barriers, the field can advance toward safer, and more effective therapies.

Exogenous RNA surveillance by proton-sensing TRIM25

Exogenous messenger RNAs (mRNAs) require cellular machinery for delivery and translation but also encounter inhibitory factors. To investigate their regulation, we performed genome-wide CRISPR screens with in vitro-transcribed mRNAs in lipid nanoparticles (LNPs). Heparan sulfate proteoglycans (HSPGs) and vacuolar adenosine triphosphatase (V-ATPase) were identified as mediators of LNP uptake and endosomal escape, respectively. TRIM25-an RNA binding E3 ubiquitin ligase-emerged as a key suppressor inducing turnover of both linear and circular mRNAs. The endoribonucleases N4BP1 and KHNYN, along with the antiviral protein ZAP, act redundantly in TRIM25-dependent surveillance. TRIM25 specifically targets mRNAs delivered by endosomes, and its RNA affinity increases at acidic pH, suggesting activation by protons released from ruptured endosomes. N1-methylpseudouridine modification reduces TRIM25's RNA binding, helping RNAs evade its suppressive effect. This study comprehensively maps cellular pathways regulating LNP-mRNAs, offering insights into RNA immunity and therapeutics.

A Nanoradiosensitizer Potentiates Tumor Radiotherapy through JFK Inhibition and Hypoxia Alleviation

Radiotherapy (RT) is a primary treatment for breast cancer, but its effectiveness is often compromised by hypoxia and intrinsic resistance mechanisms. The F-box protein JFK is overexpressed in breast cancer and is associated with reduced radiosensitivity, but specific JFK inhibitors are currently unavailable. Herein, we developed spherical nanoparticles (SNP-JC) designed to co-deliver small interfering RNA targeting JFK and catalase to the tumor, aiming to silence JFK and alleviate hypoxia to overcome RT resistance. Positron emission tomography imaging demonstrated that SNP-JC efficiently accumulated in the tumors. SNP-JC significantly increased DNA damage in tumor cells after RT and promoted the immunogenic cell death. The combination of SNP-JC and RT activated CD8+ T cells and elicited a robust antitumor immunity, resulting in suppressed primary tumor growth and reduced lung metastasis. Our findings demonstrate that a nanoplatform capable of simultaneously silencing JFK and mitigating hypoxia can enhance tumor radiosensitivity, improve antitumor efficacy, and prevent metastasis.

Formulation and Characterization of Novel Ionizable and Cationic Lipid Nanoparticles for the Delivery of Splice-Switching Oligonucleotides

Despite increasing knowledge about the mechanistic aspects of lipid nanoparticles (LNPs) as oligonucleotide carriers, the structure-function relationship in LNPs has been generally overlooked. Understanding this correlation is critical in the rational design of LNPs. Here, a materials characterization approach is utilized, applying structural information from small-angle X-ray scattering experiments to design novel LNPs focusing on distinct lipid organizations with a minimal compositional variation. The lipid phase structures are characterized in these LNPs and their corresponding bulk lipid mixtures with small-angle scattering techniques, and the LNP-cell interactions in vitro with respect to cytotoxicity, hemolysis, cargo delivery, cell uptake, and lysosomal swelling. An LNP is identified that outperforms Onpattro lipid composition using lipid components and molar ratios which differ from the gold standard clinical LNPs. The base structure of these LNPs has an inverse micellar phase organization, whereas the LNPs with inverted hexagonal phases are not functional, suggesting that this phase formation may not be needed for LNP-mediated oligonucleotide delivery. The importance of stabilizer choice for the LNP function is demonstrated and super-resolution microscopy highlights the complexity of the delivery mechanisms, where lysosomal swelling for the majority of LNPs is observed. This study highlights the importance of advanced characterization for the rational design of LNPs to enable the study of structure-function relationships.

A Supramolecular Nanoengine Generates Nanomechanical Force on Demand for Precise Cytosolic Delivery of Anti-miRNAs and Synergistic TNBC Therapy

Although anti-microRNA (miRNA) is capable of silencing target miRNA and regulating multiple mRNAs in diverse signaling pathways, RNA medicines still encounter numerous challenges, especially in terms of poor delivery, inefficient endo/lysosomal escape, and suboptimal treatment. Herein, we have developed a carrier-free supramolecular nanoengine, AMGA (anti-miRNA/GEM2-Azo), which significantly enhances the cytosolic delivery of anti-miRNA without requiring light irradiation, thereby facilitating precise targeting and synergistic chemo-gene therapy for triple-negative breast cancer (TNBC). AMGA can be rapidly internalized by cancer cells and specifically generate nanomechanical force to promote the efficient escape of anti-miRNAs from the endo/lysosome to the cytoplasm, simultaneously downregulating miR-21 and miR-10b. In comparison to Lipofectamine 2000, AMGA demonstrated superior efficacy in inhibiting the proliferation, migration, and invasion of cancer cells. Significantly, AMGA exhibited profound antitumor and gene silencing effects in an orthotopic human TNBC mouse model. This novel supramolecular nanoengine presents a promising strategy for cytosolic delivery of anti-miRNAs.

Novel Antihypertensive Medications to Target the Renin-Angiotensin System: Mechanisms and Research

An estimated 1.28 billion individuals in the global population suffer from hypertension. Importantly, uncontrolled hypertension is strongly linked to various cardiovascular and cerebrovascular diseases. The role of the renin-angiotensin system (RAS) is widely acknowledged in the development and progression of hypertension. This system comprises angiotensinogen, the renin/(pro)renin/(pro)renin receptor (PRR) axis, the renin/angiotensin-converting enzyme/angiotensin (Ang) II/Ang II type I receptor (AT1R) axis, the renin/angiotensin-converting enzyme (ACE) 2/Ang (1-7)/Mas receptor (MasR) axis, the alamandine/Mas-related G protein-coupled D (MrgD) receptor axis, and the renin/ACE/Ang II/Ang II type II receptor (AT2R) axis. Additionally, brain Ang III plays a vital role in regulating central blood pressure. The current overview presents the latest research findings on the mechanisms through which novel anti-hypertensive medications target the RAS. These include zilebesiran (targeting angiotensinogen), PRO20 (targeting the renin/(pro)renin/PRR axis), sacubitril/valsartan (targeting the renin/ACE/Ang II/AT1R axis), GSK2586881, Ang (1-7) and AVE0991 (targeting the renin/ACE2/Ang (1-7)/MasR axis), alamandine (targeting the alamandine/MrgD receptor axis), C21 and β-Pro7-Ang III (targeting the renin/ACE/Ang II/AT2R axis), EC33, and firibastat and NI956 (targeting brain Ang III).

Overcoming matrix barriers for enhanced immune infiltration using siRNA-coated metal-organic frameworks

The extracellular matrix (ECM) of solid tumor constitutes a formidable physical barrier that impedes immune cell infiltration, contributing to immunotherapy resistance. Breast cancer, particularly triple-negative breast cancer (TNBC), is characterized by a collagen-rich tumor microenvironment, which is associated with T cell exclusion and poor therapeutic outcomes. Discoidin domain receptor 2 (DDR2) and integrins, key ECM regulatory receptors on cancer cells, play pivotal role in maintaining this barrier. In this study, we developed a dual-receptor-targeted strategy using metal-organic frameworks (MOFs) to deliver DDR2-specific siRNA (siDDR2) and ITGAV-specific siRNA (siITGAV) to disrupt the ECM barrier. siDDR2 modulates immune infiltration by regulating collagen-cell interactions, while siITGAV suppresses TGF-β1 activation. The MOF@siDDR2+siITGAV complex significantly reduced collagen deposition, enhanced CD8+ T cell infiltration, and downregulated programmed cell death ligand 1 (PD-L1) expression in TNBC. Consequently, this approach markedly inhibited tumor growth. Our findings demonstrate that dual-receptor-targeted MOF-based nanocarriers (MOF@siDDR2+siITGAV) can effectively reprogram the tumor ECM to enhance immune cell access, offering a promising prospect for synergistic cancer immunotherapy. STATEMENT OF SIGNIFICANCE: A dual-receptor-targeted MOF nanocarrier is developed to improve immune accessibility in tumors. Concurrent blockade of DDR2 and ITGAV effectively decreases collagen deposition, increases CD8+ T cell infiltration, and suppresses PD-L1 expression. Modulating the mechanical properties of the extracellular matrix (ECM) to enhance immune accessibility offers an innovative strategy for cancer treatment.

Brain neurons internalise polymeric micron-sized capsules: Insights from in vitro and in vivo studies

Nanoengineered encapsulation presents a promising strategy for targeted drug delivery to specific regions in the body. While polyelectrolyte-based biodegradable microcapsules can achieve highly localised drug release in tissues and cell cultures, delivering drugs to intracellular sites in the brain remains a significant challenge. In this study, we utilized advanced imaging techniques, both in vitro and in vivo, to investigate whether brain neurons can internalise polyelectrolyte-based microcapsules designed for drug delivery. High-resolution live-cell imaging revealed that differentiating N2A cells actively internalise microcapsules, often incorporating multiple capsules per cell. Likewise, primary hippocampal and cortical neurons were observed to effectively internalise polymeric microcapsules. In the intact brain, multiplexed two-photon excitation imaging in vivo confirmed the internalisation of microcapsules by cortical neurons following delivery to the somatosensory brain region. This internalisation was time-dependent, correlated with particle size and mediated by a macropinocytosis mechanism that appears to bypass lysosomal formation. Importantly, the presence of internalised microcapsules did not impair neuronal function, as neurons maintained normal firing activity and action potential characteristics. Furthermore, no adverse effects were observed after a week of microcapsule presence in the mouse brain. Our findings indicate that polymeric microcapsules are effective and safe carriers for intracellular drug delivery to brain neurons, providing a targeted approach with potential therapeutic applications.

Enhancing Chimeric Antigen Receptor T-Cell Generation via Microfluidic Mechanoporation and Lipid Nanoparticles

Chimeric antigen receptor (CAR)-T cell therapy has revolutionized cancer treatment by engineering patients' T cells to specifically target cancer cells. Traditional CAR-T cell manufacturing methods use viral transduction to integrate CAR genes into T cells, but this can cause severe side effects and immune reactions and is costly. To overcome these challenges, non-viral methods, such as plasmid DNA (pDNA) transfection, are being explored. Here, a high-throughput intracellular delivery platform that integrates microfluidic mechanoporation with lipid nanoparticle (LNP)-based delivery, LNP + Squeeze, is introduced. This system enhances pDNA transfection efficiency in T cells while maintaining cell viability compared to other non-viral transfection methods like electroporation. This platform successfully engineers CAR-T cells using primary human T cells with a high transfection efficiency and demonstrates potent cytotoxicity against melanoma cells. This approach offers a promising, cost-effective, and scalable alternative to viral methods, potentially improving the accessibility and efficacy of CAR-T cell therapies.

Endocytic highways: Navigating macropinocytosis and other endocytic routes for precision drug delivery

Drug molecules can reach intracellular targets by different mechanisms, such as passive diffusion, active transport, and endocytosis. Endocytosis is the process by which cells engulf extracellular material by forming a vesicle and transporting it into the cells. In addition to its biological functions, endocytosis plays a vital role in the internalization of the therapeutic molecules. Clathrin-mediated endocytosis, caveolar endocytosis, and macropinocytosis are the most researched routes in the field of drug delivery. In addition to conventional small therapeutic molecules, the use of nanoformulations and large molecules, such as nucleic acids, peptides, and antibodies, have broadened the field of drug delivery. Although the majority of small therapeutic molecules can enter cells via passive diffusion, large molecules, and advanced targeted delivery systems, such as nanoparticles, are internalized by the endocytic route. Therefore, it is imperative to understand the characteristics of the endocytic routes in greater detail to design therapeutic molecules or formulations for successful delivery to the intracellular targets. This review highlights the prospects and limitations of the major endocytic routes for drug delivery, with a major emphasis on macropinocytosis. Since macropinocytosis is a non-selective uptake of extracellular matrix, the selective induction of macropinocytosis, using compounds that induce macropinocytosis and modulate macropinosome trafficking pathways, could be a potential approach for the intracellular delivery of diverse therapeutic modalities. Furthermore, we have summarized the characteristics associated with the formulations or drug carriers that can affect the endocytic routes for cellular internalization. The techniques that are used to study the intracellular uptake processes of therapeutic molecules are briefly discussed. Finally, the major limitations for intracellular targeting, endo-lysosomal degradation, and different approaches that have been used in overcoming these limitations, are highlighted in this review.

Lipid-siRNA Organization Modulates the Intracellular Dynamics of Lipid Nanoparticles

Lipid nanoparticles (LNPs) are widely used for delivering therapeutic nucleic acids, yet the relationship between their internal structure and intracellular behavior, particularly before RNA release, remains unclear. Here, we elucidate how lipid-siRNA organization within LNPs can modulate their intracellular delivery dynamics. We use cryo-electron microscopy and photochemical assays to reveal that increased siRNA loading can reduce helper lipids' distribution to the LNP surface, while siRNA consistently localizes near the surface. These alterations in lipid-siRNA organization affect LNP membrane fluidity, enhancing LNP fusion with cellular membranes and promoting cytosolic siRNA delivery, primarily via macropinocytosis. Using photosensitive lipids and live cell imaging, we demonstrate that lipid-siRNA organization regulates LNP responsiveness to external stimuli, significantly affecting siRNA endosomal escape efficiency upon light activation. We further confirm this observation using convex lens-induced confinement microscopy and single-particle imaging. Overall, our findings provide critical insights into how lipid-siRNA organization shapes LNP intracellular dynamics, offering rational design principles for optimizing LNP-based RNA therapeutics.

The Interplay of Endosomal Escape and RNA Release from Polymeric Nanoparticles

Ribonucleic acid (RNA) nanocarriers, specifically lipid nanoparticles and polymeric nanoparticles, enable RNA transfection both in vitro and in vivo; however, only a small percentage of RNA endocytosed by a cell is delivered to the cytosolic machinery, minimizing its effect. RNA nanocarriers face two major obstacles after endocytosis: endosomal escape and RNA release. Overcoming both obstacles simultaneously is challenging because endosomal escape is usually achieved by using high positive charge to disrupt the endosomal membrane. However, this high positive charge typically also inhibits RNA release because anionic RNA is strongly bound to the nanocarrier by electrostatic interactions. Many nanocarriers address one over the other despite a growing body of evidence demonstrating that both are crucial for RNA transfection. In this review, we survey the various strategies that have been employed to accomplish both endosomal escape and RNA release with a focus on polymeric nanomaterials. We first consider the various requirements a nanocarrier must achieve for RNA delivery including protection from degradation, cellular internalization, endosomal escape, and RNA release. We then discuss current polymers used for RNA delivery and examine the strategies for achieving both endosomal escape and RNA release. Finally, we review various stimuli-responsive strategies for RNA release. While RNA release continues to be a challenge in achieving efficient RNA transfection, many new innovations in polymeric materials have elucidated promising strategies.

A strategy for synergistic enhancement of immune circulation in head and neck squamous cell carcinoma by novel nucleic acid drug therapy and immunotherapy

Studies have shown that in the pathogenesis of head and neck squamous cell carcinoma, immune circulation obstruction caused by various factors including metabolic abnormalities, gene mutations, and matrix barrier, is a critical factor for the induction of tumor development and progression. Therefore, the immunotherapy strategy of killing head and neck squamous cell carcinoma cells by an enhanced immune circulation mechanism has attracted much attention. In addition, the rapid development of new nucleic acid drug therapy, such as mRNA, oligonucleotide and small guide RNA (sgRNA), has taken immunotherapy of head and neck squamous cell carcinoma (immune checkpoint inhibitors, tumor vaccines, cellular immunotherapy, cytokines and adjuvants, etc.) to a new level. The combination of nucleic acid therapy with immunotherapy developed for its therapeutic properties has brought a new direction for the diagnosis and treatment of head and neck squamous cell carcinoma, and the combination of the two has had considerable curative effect to patients with refractory/recurrent head and neck squamous cell carcinoma. In this review, we summarized the latest progress of nucleic acid therapy applied to conventional immunotherapy for head and neck squamous cell carcinoma, discussed its mechanism of action and efficacy, and looked into the future development trend.

Lipid Nanoparticles for mRNA Delivery in Cancer Immunotherapy

Cancer immunotherapy is poised to be one of the major modalities for cancer treatment. Messenger RNA (mRNA) has emerged as a versatile and promising platform for the development of effective cancer immunotherapy. Delivery systems for mRNA therapeutics are pivotal for their optimal therapeutic efficacy and minimal adverse side effects. Lipid nanoparticles (LNPs) have demonstrated a great success for mRNA delivery. Numerous LNPs have been designed and optimized to enhance mRNA stability, facilitate transfection, and ensure intracellular delivery for subsequent processing. Nevertheless, challenges remain to, for example, improve the efficiency of endosomal escape and passive targeting. This review highlights key advancements in the development of mRNA LNPs for cancer immunotherapy. We delve into the design of LNPs for mRNA delivery, encompassing the chemical structures, characterization, and structure-activity relationships (SAR) of LNP compositions. We discuss the key factors influencing the transfection efficiency, passive targeting, and tropism of mRNA-loaded LNPs. We also review the preclinical and clinical applications of mRNA LNPs in cancer immunotherapy. This review can enhance our understanding in the design and application of LNPs for mRNA delivery in cancer immunotherapy.

Glucocorticoid pre-administration improves LNP-mRNA mediated protein replacement and genome editing therapies

Lipid nanoparticles (LNPs) are among the most promising non-viral mRNA delivery systems for gene therapeutic applications. However, the in vivo delivery of LNP-mRNA remains challenging due to multiple intrinsic barriers that hinder LNPs from reaching their target cells. In this study, we sought to enhance LNP delivery by manipulating intrinsic regulatory mechanisms involved in their metabolism. We demonstrated that activation of the glucocorticoid pathway significantly increased the systemic delivery of LNP-mRNA in both mice and monkeys, achieving up to a fourfold improvement. This enhancement was primarily attributed to the glucocorticoid-mediated inhibition of macrophage phagocytosis in circulation and the liver, which resulted in higher LNP accumulation in hepatocytes. Consequently, glucocorticoid activation improved the therapeutic efficacy of LNP-based protein replacement and CRISPR/Cas9 genome editing therapies. Together, these findings establish a practical strategy to enhance the systemic delivery of RNA-based protein replacement and genome editing therapeutics, highlighting the potential of manipulating endogenous mechanisms to optimize exogenous gene delivery.

Genome-Wide CRISPR Screening Identifies Cellular Factors Controlling Nonviral Genome Editing Efficiency

After administering genome editors, their efficiency is limited by a multi-step process involving cellular uptake, trafficking, and nuclear import of the vector and its payload. These processes vary widely across cell types and differ depending on the nature and structure of the vector, whether it is a lipid nanoparticle or a different synthetic material. We developed a novel genome-wide CRISPR screening strategy to better understand these limitations within human cells to identify genes modulating cellular uptake, payload delivery, and gene editing efficiency. Our screen interrogates the cellular processes controlling genome editing by Cas-based nuclease and base editing strategies in human cells. We designed a genome-wide screen targeting 19,114 genes in HEK293 cells, and we identified six genes whose knockout increased nonviral editing efficiency in human cells by up to five-fold. Further validation through arrayed knockouts of the top hits from our screen boosted the editing efficiency from 5% to 50% when Cas9 was delivered via lipid-based nanoparticles. By designing the guides to target the screen library cassette, we could accurately track the library sgRNA identity and the editing outcome on the same amplicon via short-read sequencing, enabling the identification of rare outcomes via 'computationally' sorting edited from unedited cells within a heterogenous pool of >200M cells. In patient-derived human retinal pigment epithelium cells derived from pluripotent stem cells, BET1L, GJB2, and MS4A13 gene knockouts increased targeted genome editing by over five-fold. We anticipate that this high-throughput screening approach will facilitate the systematic engineering of novel nonviral genome editing delivery methods, where the identified novel gene hits can be further used to increase editing efficiency for other therapeutically relevant cell types.

A sort and sequence approach to dissect heterogeneity of response to a self-amplifying RNA vector in a novel human muscle cell line

Self-amplifying RNA (saRNA) is an extremely promising platform because it can produce more protein for less RNA. We used a sort and sequence approach to identify host cell factors associated with transgene expression from saRNA; the hypothesis was that cells with different expression levels would have different transcriptomes. We tested this in CDK4/hTERT immortalized human muscle cells transfected with Venezuelan equine encephalitis virus (VEEV)-derived saRNA encoding GFP. Cells with the highest expression levels had very high levels of transgene mRNA (5%-10% total reads); the cells sorted with low and negative levels of GFP protein also had detectable levels of both VEEV and GFP RNA. To understand host responses, we performed RNA sequencing. Differentially expressed gene (DEG) patterns varied with GFP expression; GFP high cells had many more DEGs, which were associated with protein synthesis and cell metabolism. Comparing profiles by an unsupervised approach revealed that negative cells expressed higher levels of cell-intrinsic immunity genes such as IFIT1, MX1, TLR3, and MyD88. To explore the role of interferon, cells were treated with the Jak inhibitor ruxolitinib. This reduced the number of DEGs, but differences between cells sorted by expression level remained. These studies demonstrate the complex interplay of factors, some immune related, affecting saRNA transgenes.

Harnessing defective interfering particles and lipid nanoparticles for effective delivery of an anti-dengue virus RNA therapy

Currently, no approved antiviral drugs target dengue virus (DENV) infection, leaving treatment reliant on supportive care. DENV vaccine efficacy varies depending on the vaccine type, the circulating serotype, and vaccine coverage. We investigated defective interfering particles (DIPs) and lipid nanoparticles (LNPs) to deliver DI290, an anti-DENV DI RNA. Both DIPs and DI290-loaded LNPs (LNP-290) effectively suppressed DENV infection in human primary monocyte-derived macrophages (MDMs), THP-1 macrophages, and fibroblasts-natural DENV targets. Inhibiting interferon (IFN) signaling with a Janus kinase 1/2 inhibitor or an IFN-α/β receptor 1 (IFNAR1)-binding antibody blocked DIP and LNP-290 antiviral activity. LNP-290 demonstrated a greater than log10 inhibition of DENV viral loads in IFNAR-deficient (Ifnar -/- ) and IFN regulatory factor (IRF) 3 and 7 double knockout (Irf3/7 -/- ) mice. Pathway analysis of RNA sequencing data from LNP-treated C57BL/6J mice, Ifnar -/- mice, and human MDMs treated with LNPs or DENV DIPs indicated DI290 treatment enhanced IFN responses, suggesting IFN-λ and IFN-γ provided antiviral activity when IFN-α/β responses were diminished. While viral interference by DI290 is possible, results did not support RNA replication competition as an inhibition mechanism. These findings suggest that DI290 may be a promising DENV therapeutic by activating the innate immune system.

Identification of Cell Receptors Responsible for Recognition and Binding of Lipid Nanoparticles

Effective delivery of lipid nanoparticles (LNPs) and their organ- or cell-type targeting are paramount for therapeutic success. Achieving this requires a comprehensive understanding of protein corona dynamics and the identification of cell receptors involved in the recognition and uptake of LNPs. We introduce a simple, fast, and in situ strategy by a biosensor-based "Fishing" method to uncover protein corona formation on LNPs and identify key receptors of human blood cells that are responsible for the recognition and binding of human plasma corona on the surface of LNPs. Unexpectedly, we observed a significant presence of immunoglobulins with high abundance, especially anti-PEG antibodies, within the LNP corona. These antibodies, along with complement opsonization, drive colony-stimulating factor 2 receptor β (CSF2RB)-mediated phagocytosis by human myeloid cells. These compositions of the human plasma corona and their interactions with neighboring proteins are critical for the recognition and binding of LNPs by cell receptors and cellular uptake. Our findings highlight the pivotal role of anti-PEG antibodies in the circulation and phagocytosis of LNPs in vivo. This approach offers profound insights into nanomaterial behavior in vivo, paving the way for the enhanced design and efficacy of LNP-based therapies.

Ionizable Lipids with Branched Linkers Enhance the Delivery of mRNA Vaccines

The emergence of mRNA vaccines has heralded an epoch in disease prevention and treatment. Safe and efficient mRNA delivery systems are highly desired for the widespread application of mRNA therapeutics. Herein, we have designed a facile synthetic pathway for producing ionizable lipids featuring various branched linkers. These lipids have been integrated into lipid nanoparticles (LNPs) to improve the delivery of mRNA vaccines. The influence of linker structure on lipids and LNPs is currently underreported, yet it undeniably exerts a substantial impact on the outcomes. Through systematic screening and formulation optimization, we have identified that LNPs comprising ionizable lipids with a branched β-isobutylglutarate linker (bLNPs) exhibited superior transfection capabilities. In preclinical cancer prevention and treatment models, mRNA vaccines delivered by bLNPs (mRNA-bLNPs) have shown significant efficacy without causing systemic toxicity, highlighting the potential of bLNPs for clinical translation. Our synthetic strategy facilitates the expansion of the LNP library and provides valuable insights into the relationship between linker structures and delivery efficiency, thereby propelling the advancement of LNP technology.