Species-agnostic polymeric formulations for inhalable messenger RNA delivery to the lung

Lipid nanoparticles encapsulating both adjuvant and antigen mRNA improve influenza immune cross-protection in mice

The rapid approval of SARS-CoV-2 mRNA lipid nanoparticle (LNP) vaccines indicates the versatility of mRNA LNPs in an urgent vaccine need. However, the mRNA vaccines do not induce mucosal cellular responses or broad protection against recent variants. To improve cross-protection of mRNA vaccines, here we engineered a pioneered mRNA LNP encapsulating with mRNA constructs encoding cytokine adjuvant and influenza A hemagglutinin (HA) antigen for intradermal vaccination. The adjuvant mRNA encodes a novel fusion cytokine GIFT4 comprising GM-CSF and IL-4. We found that the adjuvanted mRNA LNP vaccine induced high levels of humoral antibodies and systemic T cell responses against heterologous influenza antigens and protected immunized mice against influenza A viral infections. Also, the adjuvanted mRNA LNP vaccine elicited early germinal center reactions in draining lymph nodes and promoted antibody-secreting B cell responses. In addition, we generated another adjuvant mRNA encoding CCL27, which enhanced systemic immune responses. We found the two adjuvant mRNAs both showed effective adjuvanticity in enhancing humoral and cellular responses in mice. Interestingly, intradermal immunizations of GIFT4 or CCL27 mRNA adjuvanted mRNA LNP vaccines induced significant lung tissue-resident T cells. Our findings demonstrate that the cytokine mRNA can be a promising adjuvant flexibly formulated into mRNA LNP vaccines to provoke strong immunity against viral variants.

Bone-Targeting Nucleic Acid Delivery Polymer Vector for Effective Therapy of Bone Metastasis

Bone diseases, such as bone metastases, pose significant therapeutic challenges due to the distinct physiological environment of skeletal tissues, which complicates the targeted delivery of nucleic acid therapeutics. Existing delivery systems, including lipid nanoparticles (LNP) and polyethylenimine (PEI), struggle to achieve precise bone targeting effectively. To address this issue, we developed a polymer-based bone-targeting bioreducible nucleic acid delivery vector, poly[alendronic acid-co-(N,N'-bis(acryloyl)cystamine-co-4-amino-1-butanol)] (ALN-Pabol), which incorporates alendronic acid (ALN) for precise bone targeting. The ALN-Pabol exhibited a hydroxyapatite binding rate of 91.1%, significantly outperforming nontargeted Pabol/miRNA (73.5%) and commercial systems such as PEI/miRNA (58.3%) and Lipofectamine 2000/miRNA (64.7%). In vivo fluorescence imaging demonstrated its superior skeletal accumulation compared to nontargeted controls. In a murine breast cancer bone metastasis model, ALN-Pabol/miRNA polyplex reduced bone tumor weight by 79.1% relative to PBS controls and 36.8% compared to LNP/miRNA. Mechanistically, the polyplex dissociates in the high-glutathione tumor microenvironment, releasing therapeutic miRNA to suppress cancer cell proliferation and promote apoptosis. Simultaneously, ALN inhibits osteoclast activity, significantly mitigating osteolytic damage. Micro-CT analysis revealed near-complete restoration of bone volume and trabecular architecture to healthy levels. This work establishes ALN-Pabol as a highly promising delivery vector for bone-targeted gene therapy, bridging critical gaps in skeletal disease treatment and expanding potential applications in bone regeneration and cancer therapy.

Non-viral mRNA delivery to the lungs

The rapid advancement of mRNA therapeutics, exemplified by COVID-19 vaccines, underscores the transformative potential of non-viral delivery systems. However, achieving efficient and targeted mRNA delivery to the lungs remains a critical challenge due to biological barriers such as pulmonary mucus, nanoparticle instability, and off-target accumulation particularly in the liver. Addressing these challenges is crucial for advancing treatments for respiratory diseases, including cystic fibrosis, primary ciliary dyskinesia, and lung cancers. This review highlights emerging strategies to enhance lung-targeted mRNA delivery, focusing on lipid nanoparticles, polymeric nanoparticles, lipid-polymer hybrids, and peptide/protein conjugates. By discussing advances in bioinspired design and nanoparticle reformulation, this review provides a roadmap for overcoming current delivery limitations and accelerating the clinical translation of lung-targeted mRNA therapies.

A Versatile Strategy to Transform Cationic Polymers for Efficient and Organ-Selective mRNA Delivery

The progress of mRNA therapeutics underscores the imperative demand for the development of targeted delivery systems. While cationic polymers hold promise as genetic vectors, their poor in vivo efficacy and numerous variants highlight the urgent need for a universal functionalization strategy to bolster their delivery capabilities. Here, we present a versatile strategy to transform low-cost commercial cationic polymers into phospholipidated and alkylated polymers (PAPs), enabling efficient and organ-selective mRNA delivery in vivo. This straightforward post-functionalization method can be readily broadened to a diverse array of existing cationic polymers, enhancing their cellular uptake, endosomal escape, and mRNA release functionalities. Consequently, PAPs facilitate up to 30,500-fold higher mRNA expression compared to their unmodified counterparts in vivo. Notably, the one-component PAPs enable spleen-specific mRNA delivery, with their vaccine application validated in a mouse melanoma model following intravenous administration. Better still, PAPs can synergize with different helper lipids to formulate four-component lipid nanoparticles (LNPs), achieving respective lung- and liver-specific mRNA delivery. Noteworthy is that these organ-selective mRNA delivery systems significantly outperform previous polymer and LNP benchmarks. This transformation strategy for cationic polymers represents a generalized methodology to give highly effective mRNA carriers, highlighting substantial potential for clinical translation of mRNA therapies with organ-targeting requirements.

mRNA-based vaccines and therapies - a revolutionary approach for conquering fast-spreading infections and other clinical applications: a review

Since the beginning of the COVID-19 pandemic, the development of messenger RNA (mRNA) vaccines has made significant progress in the pharmaceutical industry. The two COVID-19 mRNA vaccines from Moderna and Pfizer/BioNTech have been approved for marketing and have made significant contributions to preventing the spread of SARS-CoV-2. In addition, mRNA therapy has brought hope to some diseases that do not have specific treatment methods or are difficult to treat, such as the Zika virus and influenza virus infections, as well as the prevention and treatment of tumors. With the rapid development of in vitro transcription (IVT) technology, delivery systems, and adjuvants, mRNA therapy has also been applied to hereditary diseases such as Fabry's disease. This article reviews the recent development of mRNA vaccines for structural modification, treatment and prevention of different diseases; delivery carriers and adjuvants; and routes of administration to promote the clinical application of mRNA therapies.

Inhalable liposomal delivery of osimertinib and DNA for treating primary and metastasis lung cancer

Lung cancer remains one of the most common malignancies, and its brain metastases significantly worsen the prognosis for patients. Current treatments for lung cancer face many challenges, including poor drug accumulation and the inability to simultaneously control primary and metastatic tumors. Here, we show that the mRNA-binding protein insulin-like growth factor 3 is crucial for non-small cell lung cancer progression and metastasis. We construct an inhalable nanoliposome system to co-deliver osimertinib and DNA plasmid for gene knockdown. Upon inhalation, these nanoparticles efficiently penetrate pulmonary barriers and accumulate in lungs by mimicking natural lung surfactants. Within tumor cells, released osimertinib inhibits tumor growth, while the DNA triggers the production of engineered exosomes that can travel to the brain to suppress tumors. This strategy effectively inhibits both primary and metastatic tumors while enhancing antitumor immune responses. This work suggests that this inhalable nanomedicine offers a safe and versatile strategy for cancer therapy.

Ultra-high gene transfection efficiency in suspension cells mediated by highly branched-linear poly(β-amino ester)s

Suspension cells, particularly 293F cells, are widely used for the production of therapeutic proteins, antibodies, virus-like particles (VLPs) for vaccines, and viral vectors for gene and cell therapies. However, DNA-encapsulated polyplexes typically exhibit poor interaction with the cellular membrane of suspension cells, resulting in low cellular uptake and transfection efficiency, which underscores the need for the development of more effective gene delivery systems for suspension cells. Molecular weight (MW) and topological structure are two of the most critical structural parameters that indicate the gene transfection performance of highly branched-linear poly(β-amino ester)s (H-LPAEs). Herein, we developed a series of novel H-LPAEs with varying MWs and branched structures through a two-step linear oligomer combination and branching strategy. Results demonstrate that both MW and branched structure significantly affect the multiple mechanistic steps of gene transfection. H-LPAEs with intermediate MW exhibited strong DNA binding affinity, leading to the formation of H-LPAE/DNA polyplexes with small size, favorable positive Zeta potential, high cellular uptake, and effective endosomal escape capability. Importantly, H-LPAEs 11.5 kDa achieved gene transfection efficiency of up to 84.1% and 84.5% in 293T cells and suspended human embryonic kidney cells (293F), respectively, while maintaining excellent biocompatibility. This study highlights H-LPAEs with intermediate MW provide a strong benchmark for effective transfection of both adherent and suspension cells, making them promising candidates for gene therapy.

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.

A combination of systemic mannitol and mannitol modified polyester nanoparticles for caveolae-mediated gene delivery to the brain

Overcoming the blood-brain barrier (BBB) remains a significant challenge for nucleic acid delivery to the brain. We have explored a combination of mannitol-modified poly (β-amino ester) (PBAE) nanoparticles and systemic mannitol injection for crossing the BBB. We incorporated mannitol in the PBAE polymer for caveolae targeting and selected monomers that may help avoid delivery to the liver. We also induced caveolae at the BBB through systemic mannitol injection in order to create an opportunity for the caveolae-targeting nanoparticles (M30 D90) containing plasmid DNA to cross the BBB. When a clinically relevant dose was administered intravenously in this caveolae induction model, M30 D90 demonstrated significant transgene expression of a reporter plasmid in the brain, with selective uptake by neuronal cells and minimal liver accumulation. We demonstrate that caveolae modulation using systemic mannitol administration and caveolae targeting using designed nanoparticles are necessary for efficient delivery to the brain. This delivery platform offers a simple, scalable, and controlled delivery solution and holds promise for treating brain diseases with functional targets.

Targeted Delivery of mRNA with Polymer-Lipid Nanoparticles for In Vivo Base Editing

Messenger RNA (mRNA) encoding base editors, along with single guide RNAs (sgRNAs), have emerged as a promising therapeutic approach for various disorders. However, there is still insufficient exploration in achieving targeted and efficient delivery of mRNA and sgRNA to multiple organs while ensuring high biocompatibility and stability in vivo. To address this challenge, we synthesized a library of 108 poly(β-amino) esters (PBAEs) by incorporating 100% hydrophobic side chains and end-caps with varying amines. These PBAEs were further formulated with other excipients, including helper lipids, cholesterol, and PEGylated lipids, to form polymer-lipid nanoparticles (PLNPs). Structure-function analysis revealed that eLog P of PBAEs could serve as a predictive parameter for determining the liver or lung tropism of PLNPs. The biocompatibility of PBAEs end-capped with monoamines was significantly higher compared to those end-capped with diamines. Leveraging these findings, we expanded the PBAE library and identified a leading PBAE (7C8C8) with mRNA delivery efficiency outperforming current FDA-approved ionizable lipids (ALC-0315, SM-102, and Dlin-MC3-DMA). The LD50 of the empty PLNPs (7C8C8) was determined to be 403.8 ± 49.46 mg/kg, indicating a significantly high safety profile. Additionally, PLNPs (7C8C8) demonstrated sustained transfection activity for at least 2 months when stored at -20 °C after freezing or at 4 °C following lyophilization. Subsequently, in vivo base editing using PLNPs (7C8C8) achieved an impressive editing efficiency of approximately 70% along with a significant reduction in protein levels exceeding 90%. Notably, synergistic effects were observed through simultaneous disruption of proprotein convertase subtilisin/kexin type 9 and angiopoietin-like protein 3 genes, resulting in a sustained low-density lipoprotein cholesterol reduction of over 60% for several months. These compelling findings provide strong support for the further development of PLNPs as promising platforms for mRNA-based therapies.

Poly(β-amino ester) polymer library with monomer variation for mRNA delivery

Non-viral vectors for mRNA delivery primarily include lipid nanoparticles (LNPs) and polymers. While LNPs are known for their high mRNA delivery efficiency, they can induce excessive immune responses and cause off-target effects, potentially leading to side effects. In this study, we aimed to explore polymer-based mRNA delivery systems as a viable alternative to LNPs, focusing on their mRNA delivery efficiency and potential application in mRNA vaccines. We created a library of poly(β-amino ester) (PBAE) polymers by combining various amine monomers and acrylate monomers. Through screening this polymer library, we identified specific polymer nanoparticles (PNPs) that demonstrated high mRNA expression efficiency, with sustained mRNA expression for up to two weeks. Furthermore, the PNPs showed mRNA expression only at the injection site and did not exhibit liver toxicity. Additionally, when assessing immune activation, the PNPs significantly induced T-cell immune activation and were effective in the plaque reduction neutralization test. These results suggest that polymer-based mRNA delivery systems not only hold potential for use in mRNA vaccines but also show promise for therapeutic applications.

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.

Inverted HA-EV immunization elicits stalk-specific influenza immunity and cross-protection in mice

Enhancing protective immunity in the respiratory tract is crucial to combat influenza infection and transmission. Developing mucosal universal influenza vaccines requires effective delivery platforms to overcome the respiratory mucosal barrier and stimulate appropriate innate immune reactions, thereby bridging adaptive immune responses with minimal necessary inflammation. Meanwhile, the vaccine platforms must be biocompatible. This study employed cell-derived extracellular vesicles (EVs) as a mucosal universal influenza vaccine platform. By conjugating influenza hemagglutinin (HA) onto EV surfaces through HA-receptor interaction, we achieved an upside-down (inverted) influenza HA configuration that exposed the conserved HA stalk region while partially hiding the globular head domain. Intranasal immunization with the resulting EVs induced robust HA stalk- and virus-specific serum antibody and mucosal immune responses in mice, protecting against heterologous virus infection. Notably, EVs derived from the lung epithelial cell line A549 induced superior cross-reactive antibodies and enhanced protection upon intranasal immunization. EVs conjugating multivalent HA elicited broadly cross-reactive antibody and cellular responses against different influenza strains. Our results demonstrated that EVs conjugating multiple inverted HAs represented an effective strategy for developing a mucosal universal influenza vaccine.

Ligand-free biodegradable poly(beta-amino ester) nanoparticles for targeted systemic delivery of mRNA to the lungs

Non-viral nanoparticles (NPs) have seen heightened interest as a delivery method for a variety of clinically relevant nucleic acid cargoes in recent years. While much of the focus has been on lipid NPs, non-lipid NPs, including polymeric NPs, have the possibility of improved efficacy, safety, and targeting, especially to non-liver organs following systemic administration. A safe and effective systemic approach for intracellular delivery to the lungs could overcome limitations to intratracheal/intranasal delivery of NPs and improve clinical benefit for a range of diseases including cystic fibrosis. Here, engineered biodegradable poly (beta-amino ester) (PBAE) NPs are shown to facilitate efficient delivery of mRNA to primary human airway epithelial cells from both healthy donors and individuals with cystic fibrosis. Optimized NP formulations made with differentially endcapped PBAEs and systemically administered in vivo lead to high expression of mRNA within the lungs in BALB/c and C57 B/L mice without requiring a complex targeting ligand. High levels of mRNA-based gene editing were achieved in an Ai9 mouse model across bronchial, epithelial, and endothelial cell populations. No toxicity was observed either acutely or over time, including after multiple systemic administrations of the NPs. The non-lipid biodegradable PBAE NPs demonstrate high levels of transfection in both primary human airway epithelial cells and in vivo editing of lung cell types that are targets for numerous life-limiting diseases particularly single gene disorders such as cystic fibrosis and surfactant deficiencies.

Macrophage-specific in vivo RNA editing promotes phagocytosis and antitumor immunity in mice

Macrophages play a central role in antitumor immunity, making them an attractive target for gene therapy strategies. However, macrophages are difficult to transfect because of nucleic acid sensors that can trigger the degradation of foreign plasmid DNA. Here, we developed a macrophage-specific editing (MAGE) system by which compact plasmid DNA encoding a CasRx editor can be delivered to macrophages by a poly(β-amino ester) (PBAE) carrier to bypass the DNA sensor and enable RNA editing in vitro and in vivo. We identified a four-arm branched PBAE with 1-(2-aminoethyl)-4-methylpiperazine end-capping (PBAE29) that enables highly efficient macrophage transfection. PBAE29-mediated transfection of cultured macrophages stimulated less inflammatory cytokine production and inflammasome activation compared with traditional lipofectamine or electroporation-mediated plasmid delivery. Transfection efficiency was further improved by delivering CasRx by minicircle plasmid. The MAGE system incorporated a layer of carboxylated-mannan coating to target macrophage mannose receptors and a macrophage-specific promoter for enhanced selectivity. The delivery of CasRx with guide RNA targeting the transcripts for sialic acid-binding immunoglobulin similar to lectin 10 and signal regulatory protein alpha expression resulted in effective protein knockdown, improving macrophage phagocytosis. The MAGE system also showed efficacy in targeting macrophages in vivo, stimulating antitumor immune responses and reducing tumor volume in murine tumor models, including patient-derived pancreatic adenocarcinoma xenografts in humanized mice. In sum, the MAGE system presents a promising platform for in vivo macrophage-specific delivery of RNA editing tools that can be applied as a cancer therapy.

Nebulized Lipid Nanoparticles Based on Degradable Ionizable Glycerolipid for Potent Pulmonary mRNA Delivery

As an advanced nucleic acid therapeutical modality, mRNA can express any type of protein in principle and thus holds great potential to prevent and treat various diseases. Despite the success in COVID-19 mRNA vaccines, direct local delivery of mRNA into the lung by inhalation would greatly reinforce the treatment of pulmonary pathogens and diseases. Herein, we developed lipid nanoparticles (LNPs) from degradable ionizable glycerolipids for potent pulmonary mRNA delivery via nebulization. A panel of proprietary ionizable glycerolipids with branched tails and five ester bonds were developed through a three-step esterification reaction, and LNPs formed from a lead glycerolipid identified as TG4C enabled highly efficient in vivo mRNA delivery via systemic administration with around 6-fold higher luciferase protein expression than commercial LNPs from SM102 and Dlin-MC3-DMA (MC3). Formulation screening revealed that LNPs formed at a TG4C:DOPE:cholesterol:DMG-PEG molar ratio of 50:10:38.5:1.5 (TG4C-LNPs4) had high stability against nebulization with slight changes of size distribution and mRNA encapsulation efficiency, and the nebulized TG4C-LNPs4 afforded an equivalent percentage of positive cells and a slightly lower EGFP fluorescence intensity in lung cell lines (A549, BEAS-2B). Following pulmonary delivery in mice, TG4C-LNPs4 induced efficient transfection in the majority of epithelial cells in the lung, leading to apparent bioluminescence evenly distributed in all five lung lobes. In an elastase-induced emphysema model in mice, TG4C-LNPs4 loaded with mRNA encoding hepatocyte growth factor could significantly suppress the secretion of inflammatory cytokines (IL-1β, IL-6, and TNF-α) in bronchoalveolar lavage fluid and counteract the alveoli wall thinning. Notably, partial substitution (25%) of cholesterol with budesonide, an anti-inflammatory glucocorticoid, in TG4C-LNPs4 generated equivalent protein expression and significantly improved therapeutic efficacy. Taken together, our study provides robust and high-performing nanovehicles based on degradable ionizable glycerolipids, enabling potently local mRNA delivery to the lung for the treatment of pulmonary diseases.

Interaction design in mRNA delivery systems

Following the coronavirus disease 2019 (COVID-19) pandemic, mRNA technology has made significant breakthroughs, emerging as a potential universal platform for combating various diseases. To address the challenges associated with mRNA delivery, such as instability and limited delivery efficacy, continuous advancements in genetic engineering and nanotechnology have led to the exploration and refinement of various mRNA structural modifications and delivery platforms. These achievements have significantly broadened the clinical applications of mRNA therapies. Despite the progress, the understanding of the interactions in mRNA delivery systems remains limited. These interactions are complex and multi-dimensional, occurring between mRNA and vehicles as well as delivery materials and helper ingredients. Resultantly, stability of the mRNA delivery systems and their delivery efficiency can be both significantly affected. This review outlines the current state of mRNA delivery strategies and summarizes the interactions in mRNA delivery systems. The interactions include the electrostatic interactions, hydrophobic interactions, hydrogen bonding, π-π stacking, coordination interactions, and so on. This interaction understanding provides guideline for future design of next-generation mRNA delivery systems, thereby offering new perspectives and strategies for developing diverse mRNA therapeutics.

Synthetic Nanocapsules with Tailored Surface Chemistry for Lung-Specific Protein Delivery and Cancer Immunotherapy

Efficient delivery of therapeutic proteins remains a major challenge in developing effective immunotherapies and treatments for genetic disorders due to the limited tissue targeting capability of native proteins. In this study, the design and synthesis of protein nanocapsules (NCs) that achieve lung-specific delivery of therapeutic proteins are reported. These NCs are synthesized through a surface modification process that involves coating protein with functional monomers and cross-linkers, followed by in situ polymerization to create a protective shell on the protein surface with tailored surface chemistry. This approach preserves protein integrity and significantly enhances delivery efficiency and tissue specificity. Notably, it is shown that protein@NC with guanidine-rich surfaces exhibit exceptional lung-targeting capabilities. This is likely attributed to the formation of a vitronectin-rich protein corona, which facilitates receptor-mediated endocytosis by lung cells. The platform effectively delivers various proteins, such as ovalbumin, to antigen-presenting cells (APCs) in the lung, thereby enhancing antigen presentation and offering a promising strategy for cancer immunotherapy. These findings provide a significant advancement in tissue-specific protein delivery and hold the potential for targeted cancer immunotherapy.

Crown-like Biodegradable Lipids Enable Lung-Selective mRNA Delivery and Dual-Modal Tumor Imaging In Vivo

Systemic mRNA delivery to specific cell types remains a great challenge. We herein report a new class of crown-like biodegradable ionizable lipids (CBILs) for predictable lung-selective mRNA delivery by leveraging the metal coordination chemistry. Each CBIL contains an impressive crown-like amino core that coordinates with various metal ions such as Zn2+ and further regulates the in vivo organ-targeting behavior of lipid nanoparticles (LNPs). The representative CBIL (Zn-9C-SCC-10)-formulated LNPs could exclusively deliver mRNA to the lung after systemic administration. Notably, following intravenous administration of 0.2 mg kg-1 Cre mRNA, Zn-9C-SCC-10 LNPs enabled the highly efficient gene editing of all lung epithelial and endothelial cells up to 43 and 61%, respectively, outperforming the current state-of-the-art LNPs in lung epithelial cell delivery. Moreover, compared to DLin-MC3-DMA LNPs with the addition of cationic lipid (DOTAP), our approach yielded a 44.6-fold enhancement in pulmonary mRNA expression and significantly improved biosafety in vivo. Taking advantage of paramagnetic gadolinium ion, Gd-12C-SCC-10 LNPs allowed the potent mRNA delivery to cancer cells and successfully illuminated lung tumors by magnetic and bioluminescent dual-mode imaging, facilitating the early discovery and diagnosis of lung cancer. This work will open a new avenue to rationally design predictable LNPs, as well as address the major challenges of mRNA delivery to specific cells in the lung tissues for treating a wide variety of diseases.

Artificial intelligence-guided design of lipid nanoparticles for pulmonary gene therapy

Ionizable lipids are a key component of lipid nanoparticles, the leading nonviral messenger RNA delivery technology. Here, to advance the identification of ionizable lipids beyond current methods, which rely on experimental screening and/or rational design, we introduce lipid optimization using neural networks, a deep-learning strategy for ionizable lipid design. We created a dataset of >9,000 lipid nanoparticle activity measurements and used it to train a directed message-passing neural network for prediction of nucleic acid delivery with diverse lipid structures. Lipid optimization using neural networks predicted RNA delivery in vitro and in vivo and extrapolated to structures divergent from the training set. We evaluated 1.6 million lipids in silico and identified two structures, FO-32 and FO-35, with local mRNA delivery to the mouse muscle and nasal mucosa. FO-32 matched the state of the art for nebulized mRNA delivery to the mouse lung, and both FO-32 and FO-35 efficiently delivered mRNA to ferret lungs. Overall, this work shows the utility of deep learning for improving nanoparticle delivery.

Nanoparticles to target asthma

Asthma is a heterogeneous chronic lung disease that affects nearly 340 million people globally. Airway hyperresponsiveness, remodeling (thickening and fibrosis), and mucus hypersecretion are some hallmarks of asthma. With several current treatments having serious side effects from long-term use and a proportion of patients with uncontrolled asthma, there is an urgent need for new therapies. With an increasing understanding of asthma pathophysiology, there is a recognized need to target therapies to specific cell types of the airway, which necessitates the identification of delivery systems that can overcome increased mucus and thickened airways. Nanoparticles (NPs) that are highly customizable (material, size, charge, and surface modification) are a potential solution for delivery systems of a wide variety of cargoes (nucleic acids, proteins, and/or small molecules), as well as sole therapeutics for asthma. However, there is a need to consider the safety of the NPs in terms of potential for inflammation, toxicity, nonspecific targets, and accumulation in organs. Ongoing clinical trials using NPs, some FDA-approved for therapeutics in other diseases, provide confidence regarding the potential safety and efficacy of NPs in asthma treatment. This review highlights the current state of the use of NPs in asthma, identifying opportunities for further improvements in NP design and utilization for targeting this chronic lung disease.

Drug nanocrystals: Surface engineering and its applications in targeted delivery

Drug nanocrystals have received significant attention in drug development due to their enhanced dissolution rate and improved water solubility, making them effective in overcoming issues related to drug hydrophobicity, thereby improving drug bioavailability and treatment effectiveness. Recent advances in preparation techniques have facilitated research on drug surface properties, leading to valuable surface engineering strategies. Surface modification can stabilize drug nanocrystals, making them suitable for versatile drug delivery platforms. Functionalized ligands further enhance the potential for targeted delivery, enabling precision medicine. This review focuses on the surface engineering of drug nanocrystals, discussing various preparation methods, surface ligand design strategies, and their applications in targeted drug delivery, especially for cancer treatments. Finally, challenges and future directions are also discussed to promote the development of drug nanocrystals. The surface engineering of drug nanocrystals promises new opportunities for treating complex and chronic diseases while broadening the application of drug delivery systems.

Charge-assisted stabilization of lipid nanoparticles enables inhaled mRNA delivery for mucosal vaccination

Inhaled delivery of messenger RNA (mRNA) using lipid nanoparticle (LNP) holds immense promise for treating pulmonary diseases or serving as a mucosal vaccine. However, the unsatisfactory delivery efficacy caused by the disintegration and aggregation of LNP during nebulization represents a major obstacle. To address this, we develop a charge-assisted stabilization (CAS) strategy aimed at inducing electrostatic repulsions among LNPs to enhance their colloidal stability. By optimizing the surface charges using a peptide-lipid conjugate, the leading CAS-LNP demonstrates exceptional stability during nebulization, resulting in efficient pulmonary mRNA delivery in mouse, dog, and pig. Inhaled CAS-LNP primarily transfect dendritic cells, triggering robust mucosal and systemic immune responses. We demonstrate the efficacy of inhaled CAS-LNP as a vaccine for SARS-CoV-2 Omicron variant and as a cancer vaccine to inhibit lung metastasis. Our findings illustrate the design principles of nebulized LNPs, paving the way of developing inhaled mRNA vaccines and therapeutics.

siRNA Nanoparticle Dry Powder Formulation with High Transfection Efficiency and Pulmonary Deposition for Acute Lung Injury Treatment

Acute lung injury (ALI) is a severe inflammatory syndrome, which was caused by diverse factors. The COVID-19 pandemic has resulted in a higher mortality rate of these conditions. Currently, effective treatments are lacking. Although siRNA nucleotide-based drugs are promising therapeutic approaches, their poor stability and inability to efficiently reach target cells limit their clinical translation. This study identified a peptide from known cell-penetrating peptides that can form an efficient anti-inflammatory complex with TNF-α siRNA, termed SAR6EW/TNF-α siRNA. This complex can effectively transport TNF-α siRNA into the cytoplasm and achieve potent gene silencing in vitro as well as in vivo. By using lactose and triarginine as coexcipients and optimizing the spray-drying process, a powder was produced with micrometer-scale spherical and porous structures, enhancing aerosol release and lung delivery efficiency. The dry powder formulation and process preserve the stability and integrity of the siRNA. When administered intratracheally to ALI model mice, the complex powder demonstrated specific pulmonary gene silencing activity and significantly reduced inflammation symptoms caused by ALI, suggesting a potential strategy for the clinical therapeutic approach of respiratory diseases.

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.

Stimuli-Responsive Polymers at the Interface with Biology

There has been growing interest in polymeric systems that break down or undergo property changes in response to stimuli. Such polymers can play important roles in biological systems, where they can be used to control the release of therapeutics, modulate imaging signals, actuate movement, or direct the growth of cells. In this Perspective, after discussing the most important stimuli relevant to biological applications, we will present a selection of recent exciting developments. The growing importance of stimuli-responsive polysaccharides will be discussed, followed by a variety of stimuli-responsive polymeric systems for the delivery of small molecule drugs and nucleic acids. Switchable polymers for the emerging area of therapeutic response measurement in theranostics will be described. Then, the diverse functions that can be achieved using hydrogels cross-linked covalently, as well as by various dynamic approaches will be presented. Finally, we will discuss some of the challenges and future perspectives for the field.

Delivery vehicle and route of administration influences self-amplifying RNA biodistribution, expression kinetics, and reactogenicity

Self-amplifying RNA (saRNA) is a next-generation RNA platform derived from an alphavirus that enables replication in host cytosol, offering a promising shift from traditional messenger RNA (mRNA) therapies by enabling sustained protein production from minimal dosages. The approval of saRNA-based vaccines, such as the ARCT-154 for COVID-19 in Japan, underscores its potential for diverse therapeutic applications, including vaccine development, cancer immunotherapy, and gene therapy. This study investigates the role of delivery vehicle and administration route on saRNA expression kinetics and reactogenicity. Employing ionizable lipid-based nanoparticles (LNPs) and polymeric nanoparticles, we administered saRNA encoding firefly luciferase to BALB/c mice through six routes (intramuscular (IM), intradermal (ID), intraperitoneal (IP), intranasal (IN), intravenous (IV), and subcutaneous (SC)), and observed persistent saRNA expression over a month. Our findings reveal that while LNPs enable broad route applicability and stability, pABOL (poly (cystamine bisacrylamide-co-4-amino-1-butanol)) formulations significantly amplify protein expression via intramuscular delivery. Notably, the disparity between RNA biodistribution and protein expression highlight the nuanced interplay between administration routes, delivery vehicles, and therapeutic outcomes. Additionally, our research unveiled distinct biodistribution profiles and inflammatory responses contingent upon the chosen delivery formulation and route. This research illuminates the intricate dynamics governing saRNA delivery, biodistribution and reactogenicity, offering essential insights for optimizing therapeutic strategies and advancing the clinical and commercial viability of saRNA technologies.

Advancing mRNA Therapeutics: The Role and Future of Nanoparticle Delivery Systems

The coronavirus (COVID-19) pandemic has underscored the critical role of mRNA-based vaccines as powerful, adaptable, readily manufacturable, and safe methodologies for prophylaxis. mRNA-based treatments are emerging as a hopeful avenue for a plethora of conditions, encompassing infectious diseases, cancer, autoimmune diseases, genetic diseases, and rare disorders. Nonetheless, the in vivo delivery of mRNA faces challenges due to its instability, suboptimal delivery, and potential for triggering undesired immune reactions. In this context, the development of effective drug delivery systems, particularly nanoparticles (NPs), is paramount. Tailored with biophysical and chemical properties and susceptible to surface customization, these NPs have demonstrated enhanced mRNA delivery in vivo and led to the approval of several NPs-based formulations for clinical use. Despite these advancements, the necessity for developing a refined, targeted NP delivery system remains imperative. This review comprehensively surveys the biological, translational, and clinical progress in NPs-mediated mRNA therapeutics for both the prevention and treatment of diverse diseases. By addressing critical factors for enhancing existing methodologies, it aims to inform the future development of precise and efficacious mRNA-based therapeutic interventions.

Beyond Lipids: Exploring Advances in Polymeric Gene Delivery in the Lipid Nanoparticles Era

The recent success of gene therapy during the COVID-19 pandemic has underscored the importance of effective and safe delivery systems. Complementing lipid-based delivery systems, polymers present a promising alternative for gene delivery. Significant advances have been made in the recent past, with multiple clinical trials progressing beyond phase I and several companies actively working on polymeric delivery systems which provides assurance that polymeric carriers can soon achieve clinical translation. The massive advantage of structural tunability and vast chemical space of polymers is being actively leveraged to mitigate shortcomings of traditional polycationic polymers and improve the translatability of delivery systems. Tailored polymeric approaches for diverse nucleic acids and for specific subcellular targets are now being designed to improve therapeutic efficacy. This review describes the recent advances in polymer design for improved gene delivery by polyplexes and covalent polymer-nucleic acid conjugates. The review also offers a brief note on novel computational techniques for improved polymer design. The review concludes with an overview of the current state of polymeric gene therapies in the clinic as well as future directions on their translation to the clinic.

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.

mRNA-encoded Cas13 can be used to treat dengue infections in mice

Dengue is a major global health threat, and there are no approved antiviral agents. Prior research using Cas13 only demonstrated dengue mitigation in vitro. Here we demonstrate that systemic delivery of mRNA-encoded Cas13a and guide RNAs formulated in lipid nanoparticles can be used to treat dengue virus (DENV) 2 and 3 in mice. First, we identified guides against DENV 2 and 3 that demonstrated in vitro efficacy. Next, we confirmed that Cas13 enzymatic activity is necessary for DENV 2 or DENV 3 mitigation in vitro. Last, we show that a single dose of lipid-nanoparticle-formulated mRNA-encoded Cas13a and guide RNA, administered 1 day post-infection, promotes survival of all infected animals and serum viral titre decreases on days 2 and 3 post-infection after lethal challenge in mice. Off-target analysis in mice using RNA sequencing showed no collateral cleavage. Overall, these data demonstrate the potential of mRNA-encoded Cas13 as a pan-DENV drug.

Aerosol Inhalation of Gene Delivery Therapy for Pulmonary Diseases

Gene delivery therapy has emerged as a popular approach for the treatment of various diseases. However, it still poses the challenges of accumulation in target sites and reducing off-target effects. Aerosol gene delivery for the treatment of pulmonary diseases has the advantages of high lung accumulation, specific targeting and fewer systemic side effects. However, the key challenge is selecting the appropriate formulation for aerosol gene delivery that can overcome physiological barriers. There are numerous existing gene carriers under study, including viral vectors and non-viral vectors. With the development of biomaterials, more biocompatible substances have applied gene delivery via inhalation. Furthermore, many types of genes can be delivered through aerosol inhalation, such as DNA, mRNA, siRNA and CRISPR/Cas9. Aerosol delivery of different types of genes has proven to be efficient in the treatment of many diseases such as SARS-CoV-2, cystic fibrosis and lung cancer. In this paper, we provide a comprehensive review of the ongoing research on aerosol gene delivery therapy, including the basic respiratory system, different types of gene carriers, different types of carried genes and clinical applications.

Tailoring Highly Branched Poly(β-amino ester)s for Efficient and Organ-Selective mRNA Delivery

Development of mRNA therapeutics necessitates targeted delivery technology, while the clinically advanced lipid nanoparticles face difficulty for extrahepatic delivery. Herein, we design highly branched poly(β-amino ester)s (HPAEs) for efficacious organ-selective mRNA delivery through tailoring their chemical compositions and topological structures. Using an "A2+B3+C2" Michael addition platform, a combinatorial library of 219 HPAEs with varied backbone structures, terminal groups, and branching degrees are synthesized. The branched topological structures of HPAEs provide enhanced serum resistance and significantly higher mRNA expression in vivo. The terminal amine structures of HPAEs determine the organ-selectivity of mRNA delivery following systemic administration: morpholine facilitates liver targeting, ethylenediamine favors spleen delivery, while methylpentane enables mRNA delivery to the liver, spleen, and lungs simultaneously. This study represents a comprehensive exploration of the structure-activity relationship governing both the efficiency and organ-selectivity of mRNA delivery by HPAEs, suggesting promising candidates for treating various organ-related diseases.

Emerging mRNA Technology for Liver Disease Therapy

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

Recent Developments in Aerosol Pulmonary Drug Delivery: New Technologies, New Cargos, and New Targets

There is nothing like a global pandemic to motivate the need for improved respiratory treatments and mucosal vaccines. Stimulated by the COVID-19 pandemic, pulmonary aerosol drug delivery has seen a flourish of activity, building on the prior decades of innovation in particle engineering, inhaler device technologies, and clinical understanding. As such, the field has expanded into new directions and is working toward the efficient delivery of increasingly complex cargos to address a wider range of respiratory diseases. This review seeks to highlight recent innovations in approaches to personalize inhalation drug delivery, deliver complex cargos, and diversify the targets treated and prevented through pulmonary drug delivery. We aim to inform readers of the emerging efforts within the field and predict where future breakthroughs are expected to impact the treatment of respiratory diseases.

K. P, Jeong H, Jung Y, Assumpção JAF, Peck HE, Nelson SL, Burke KN, Garrison MA, Arthur RA, Claussen H, Heaton NS, Lafontaine ER, Hogan RJ, Zurla C, Santangelo PJ. mRNA-encoded Cas13 treatment of Influenza via site-specific degradation of genomic RNA

The CRISPR-Cas13 system has been proposed as an alternative treatment of viral infections. However, for this approach to be adopted as an antiviral, it must be optimized until levels of efficacy rival or exceed the performance of conventional approaches. To take steps toward this goal, we evaluated the influenza viral RNA degradation patterns resulting from the binding and enzymatic activity of mRNA-encoded LbuCas13a and two crRNAs from a prior study, targeting PB2 genomic and messenger RNA. We found that the genome targeting guide has the potential for significantly higher potency than originally detected, because degradation of the genomic RNA is not uniform across the PB2 segment, but it is augmented in proximity to the Cas13 binding site. The PB2 genome targeting guide exhibited high levels (>1 log) of RNA degradation when delivered 24 hours post-infection in vitro and maintained that level of degradation over time, with increasing multiplicity of infection (MOI), and across modern influenza H1N1 and H3N2 strains. Chemical modifications to guides with potent LbuCas13a function, resulted in nebulizer delivered efficacy (>1-2 log reduction in viral titer) in a hamster model of influenza (Influenza A/H1N1/California/04/09) infection given prophylactically or as a treatment (post-infection). Maximum efficacy was achieved with two doses, when administered both pre- and post-infection. This work provides evidence that mRNA-encoded Cas13a can effectively mitigate Influenza A infections opening the door to the development of a programmable approach to treating multiple respiratory infections.

Cavitation is the determining mechanism for the atomization of high-viscosity liquid

Piezoelectric atomization is becoming mainstream in the field of inhalation therapy due to its significant advantages. With the rapid development of high-viscosity gene therapy drugs, the demand for piezoelectric atomization devices is increasing. However, conventional piezoelectric atomizers with a single-dimensional energy supply are unable to provide the energy required to atomize high-viscosity liquids. To address this problem, our team has designed a flow tube internal cavitation atomizer (FTICA). This study focuses on dissecting the atomization mechanism of FTICA. In contrast to the widely supported capillary wave hypothesis, our study provides evidence in favor of the cavitation hypothesis, proving that cavitation is the key to atomizing high-viscosity liquids with FTICA. In order to prove that the cavitation is the key to atomizing in the structure of FTICA, the performance of atomization is experimented after changing the cavitation conditions by heating and stirring of the liquids.

Biohybrid microrobots locally and actively deliver drug-loaded nanoparticles to inhibit the progression of lung metastasis

Lung metastasis poses a formidable challenge in the realm of cancer treatment, with conventional chemotherapy often falling short due to limited targeting and low accumulation in the lungs. Here, we show a microrobot approach using motile algae for localized delivery of drug-loaded nanoparticles to address lung metastasis challenges. The biohybrid microrobot [denoted "algae-NP(DOX)-robot"] combines green microalgae with red blood cell membrane-coated nanoparticles containing doxorubicin, a representative chemotherapeutic drug. Microalgae provide autonomous propulsion in the lungs, leveraging controlled drug release and enhanced drug dispersion to exert antimetastatic effects. Upon intratracheal administration, algae-NP(DOX)-robots efficiently transport their drug payload deep into the lungs while maintaining continuous motility. This strategy leads to rapid drug distribution, improved tissue accumulation, and prolonged retention compared to passive drug-loaded nanoparticles and free drug controls. In a melanoma lung metastasis model, algae-NP(DOX)-robots exhibit substantial improvement in therapeutic efficacy, reducing metastatic burden and extending survival compared to control groups.

Synthesis of ionizable lipopolymers using split-Ugi reaction for pulmonary delivery of various size RNAs and gene editing

We present an efficient approach for synthesizing cationic poly(ethylene imine) derivatives using the multicomponent split-Ugi reaction to rapidly create a library of complex functional ionizable lipopolymers. We synthesized a diverse library of 155 polymers, formulated them into polyplexes to establish structure-activity relationships crucial for endosomal escape and efficient transfection. After discovering a lead structure, lipopolymer-lipid hybrid nanoparticles are introduced to preferentially deliver to and elicit effective mRNA transfection in lung endothelium and immune cells, including T cells with low in vivo toxicity. The lipopolymer-lipid hybrid nanoparticles showed 300-fold improvement in systemic mRNA delivery to the lung compared to in vivo -JetPEI ® . Lipopolymer-lipid hybrid nanoparticles demonstrated efficient delivery of mRNA-based therapeutics for treatment of two different disease models. Lewis Lung cancer progression was significantly delayed after treatment with loaded IL-12 mRNA in U155@lipids after repeated i.v. administration. Systemic delivery of human CFTR (hCFTR) mRNA resulted in production of functional form of CFTR protein in the lungs. The functionality of hCFTR protein was confirmed by restoration of CFTR- mediated chloride secretion in conductive airway epithelia in CFTR knockout mice after nasal instillation of hCFTR mRNA loaded U155@lipids. We further showed that, U155@lipids nanoparticles can deliver complex CRISPR-Cas9 based RNA cargo to the lung, achieving 5.6 ± 2.4 % gene editing in lung tissue. Moreover, we demonstrated successful PD-1 gene knockout of T cells in vivo . Our results highlight a versatile delivery platform for systemic delivering of mRNA of various sizes for gene therapy for a variety of therapeutics.

Cationic Lipid Pairs Enhance Liver-to-Lung Tropism of Lipid Nanoparticles for In Vivo mRNA Delivery

Much of current clinical interest has focused on mRNA therapeutics for the treatment of lung-associated diseases, such as infections, genetic disorders, and cancers. However, the safe and efficient delivery of mRNA therapeutics to the lungs, especially to different pulmonary cell types, is still a formidable challenge. In this paper, we proposed a cationic lipid pair (CLP) strategy, which utilized the liver-targeted ionizable lipid and its derived quaternary ammonium lipid as the CLP to improve liver-to-lung tropism of four-component lipid nanoparticles (LNPs) for in vivo mRNA delivery. Interestingly, the structure-activity investigation identified that using liver-targeted ionizable lipids with higher mRNA delivery performance and their derived lipid counterparts is the optimal CLP design for improving lung-targeted mRNA delivery. The CLP strategy was also verified to be universal and suitable for clinically available ionizable lipids such as SM-102 and ALC-0315 to develop lung-targeted LNP delivery systems. Moreover, we demonstrated that CLP-based LNPs were safe and exhibited potent mRNA transfection in pulmonary endothelial and epithelial cells. As a result, we provided a powerful CLP strategy for shifting the mRNA delivery preference of LNPs from the liver to the lungs, exhibiting great potential for broadening the application scenario of mRNA-based therapy.

Recent Progress in Nucleic Acid Pulmonary Delivery toward Overcoming Physiological Barriers and Improving Transfection Efficiency

Pulmonary delivery of therapeutic agents has been considered the desirable administration route for local lung disease treatment. As the latest generation of therapeutic agents, nucleic acid has been gradually developed as gene therapy for local diseases such as asthma, chronic obstructive pulmonary diseases, and lung fibrosis. The features of nucleic acid, specific physiological structure, and pathophysiological barriers of the respiratory tract have strongly affected the delivery efficiency and pulmonary bioavailability of nucleic acid, directly related to the treatment outcomes. The development of pharmaceutics and material science provides the potential for highly effective pulmonary medicine delivery. In this review, the key factors and barriers are first introduced that affect the pulmonary delivery and bioavailability of nucleic acids. The advanced inhaled materials for nucleic acid delivery are further summarized. The recent progress of platform designs for improving the pulmonary delivery efficiency of nucleic acids and their therapeutic outcomes have been systematically analyzed, with the application and the perspectives of advanced vectors for pulmonary gene delivery.

Targeted Macrophage CRISPR-Cas13 mRNA Editing in Immunotherapy for Tendon Injury

CRISPR-Cas13 holds substantial promise for tissue repair through its RNA editing capabilities and swift catabolism. However, conventional delivery methods fall short in addressing the heightened inflammatory response orchestrated by macrophages during the acute stages of tendon injury. In this investigation, macrophage-targeting cationic polymers are systematically screened to facilitate the entry of Cas13 ribonucleic-protein complex (Cas13 RNP) into macrophages. Notably, SPP1 (OPN encoding)-producing macrophages are recognized as a profibrotic subtype that emerges during the inflammatory stage. By employing ROS-responsive release mechanisms tailored for macrophage-targeted Cas13 RNP editing systems, the overactivation of SPP1 is curbed in the face of an acute immune microenvironment. Upon encapsulating this composite membrane around the tendon injury site, the macrophage-targeted Cas13 RNP effectively curtails the emergence of injury-induced SPP1-producing macrophages in the acute phase, leading to diminished fibroblast activation and mitigated peritendinous adhesion. Consequently, this study furnishes a swift RNA editing strategy for macrophages in the inflammatory phase triggered by ROS in tendon injury, along with a pioneering macrophage-targeted carrier proficient in delivering Cas13 into macrophages efficiently.

Microfluidic Platform Enables Shearless Aerosolization of Lipid Nanoparticles for mRNA Inhalation

Leveraging the extensive surface area of the lungs for gene therapy, the inhalation route offers distinct advantages for delivery. Clinical nebulizers that employ vibrating mesh technology are the standard choice for converting liquid medicines into aerosols. However, they have limitations when it comes to delivering mRNA through inhalation, including severe damage to nanoparticles due to shearing forces. Here, we introduce a microfluidic aerosolization platform (MAP) that preserves the structural and physicochemical integrity of lipid nanoparticles, enabling safe and efficient delivery of mRNA to the respiratory system. Our results demonstrated the superiority of the MAP over the conventional vibrating mesh nebulizer, as it avoided problems such as particle aggregation, loss of mRNA encapsulation, and deformation of the nanoparticle morphology. Notably, aerosolized nanoparticles generated by the microfluidic device led to enhanced transfection efficiency across various cell lines. In vivo experiments with mice that inhaled these aerosolized nanoparticles revealed successful lung-specific mRNA transfection without observable signs of toxicity. This MAP may represent an advancement for the pulmonary gene therapy, enabling precise and effective delivery of aerosolized nanoparticles.

Combinatorial discovery of antibacterials via a feature-fusion based machine learning workflow

The discovery of new antibacterials within the vast chemical space is crucial in combating drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). However, the traditional approach of screening the entire chemical library in an ergodic manner can be laborious and time-consuming. Machine learning-assisted screening of antibacterials alleviates the exploration effort but suffers from the lack of reliable and related datasets. To address these challenges, we devised a combinatorial library comprising over 110 000 candidates based on the Ugi reaction. A focused library was subsequently generated through uniform sampling of the entire library to narrow down the preliminary screening scale. A novel feature-fusion architecture called the latent space constraint neural network was developed which incorporated both fingerprint and physicochemical molecular descriptors to predict the antibacterial properties. This integration allowed the model to leverage the complementary information provided by these descriptors and improve the accuracy of predictions. Three lead compounds that demonstrated excellent efficacy against MRSA while alleviating drug resistance were identified. This workflow highlights the integration of machine learning with the combinatorial chemical library to expedite high-quality data collection and extensive data mining for antibacterial screening.

Anticancer and Antibacterial Properties of Curcumin-Loaded Mannosylated Solid Lipid Nanoparticles for the Treatment of Lung Diseases

Lung cancer and Mycobacterium avium complex infection are lung diseases associated with high incidence and mortality rates. Most conventional anticancer drugs and antibiotics have certain limitations, including high drug resistance rates and adverse effects. Herein, we aimed to synthesize mannose surface-modified solid lipid nanoparticles (SLNs) loaded with curcumin (Man-CUR SLN) for the effective treatment of lung disease. The synthesized Man-CUR SLNs were analyzed using various instrumental techniques for structural and physicochemical characterization. Loading curcumin into SLNs improved the encapsulation efficiency and drug release capacity, as demonstrated by high-performance liquid chromatography analysis. Furthermore, we characterized the anticancer effect of curcumin using the A549 lung cancer cell line. Cells treated with Man-CUR SLN exhibited an increased cellular uptake and cytotoxicity. Moreover, treatment with free CUR could more effectively reduce cancer migration than treatment with Man-CUR SLNs. Similarly, free curcumin elicited a stronger apoptosis-inducing effect than that of Man-CUR SLNs, as demonstrated by reverse transcription-quantitative PCR analysis. Finally, we examined the antibacterial effects of free curcumin and Man-CUR SLNs against Mycobacterium intracellulare (M.i.) and M.i.-infected macrophages, revealing that Man-CUR SLNs exerted the strongest antibacterial effect. Collectively, these findings indicate that mannose-receptor-targeted curcumin delivery using lipid nanoparticles could be effective in treating lung diseases. Accordingly, this drug delivery system can be used to target a variety of cancers and immune cells.

Strategies for non-viral vectors targeting organs beyond the liver

In recent years, nanoparticles have evolved to a clinical modality to deliver diverse nucleic acids. Rising interest in nanomedicines comes from proven safety and efficacy profiles established by continuous efforts to optimize physicochemical properties and endosomal escape. However, despite their transformative impact on the pharmaceutical industry, the clinical use of non-viral nucleic acid delivery is limited to hepatic diseases and vaccines due to liver accumulation. Overcoming liver tropism of nanoparticles is vital to meet clinical needs in other organs. Understanding the anatomical structure and physiological features of various organs would help to identify potential strategies for fine-tuning nanoparticle characteristics. In this Review, we discuss the source of liver tropism of non-viral vectors, present a brief overview of biological structure, processes and barriers in select organs, highlight approaches available to reach non-liver targets, and discuss techniques to accelerate the discovery of non-hepatic therapies.

Prediction of on-target and off-target activity of CRISPR-Cas13d guide RNAs using deep learning

Transcriptome engineering applications in living cells with RNA-targeting CRISPR effectors depend on accurate prediction of on-target activity and off-target avoidance. Here we design and test ~200,000 RfxCas13d guide RNAs targeting essential genes in human cells with systematically designed mismatches and insertions and deletions (indels). We find that mismatches and indels have a position- and context-dependent impact on Cas13d activity, and mismatches that result in G-U wobble pairings are better tolerated than other single-base mismatches. Using this large-scale dataset, we train a convolutional neural network that we term targeted inhibition of gene expression via gRNA design (TIGER) to predict efficacy from guide sequence and context. TIGER outperforms the existing models at predicting on-target and off-target activity on our dataset and published datasets. We show that TIGER scoring combined with specific mismatches yields the first general framework to modulate transcript expression, enabling the use of RNA-targeting CRISPRs to precisely control gene dosage.

Engineered mRNA Delivery Systems for Biomedical Applications

Messenger RNA (mRNA)-based therapeutic strategies have shown remarkable promise in preventing and treating a staggering range of diseases. Optimizing the structure and delivery system of engineered mRNA has greatly improved its stability, immunogenicity, and protein expression levels, which has led to a wider range of uses for mRNA therapeutics. Herein, a thorough analysis of the optimization strategies used in the structure of mRNA is first provided and delivery systems are described in great detail. Furthermore, the latest advancements in biomedical engineering for mRNA technology, including its applications in combatting infectious diseases, treating cancer, providing protein replacement therapy, conducting gene editing, and more, are summarized. Lastly, a perspective on forthcoming challenges and prospects concerning the advancement of mRNA therapeutics is offered. Despite these challenges, mRNA-based therapeutics remain promising, with the potential to revolutionize disease treatment and contribute to significant advancements in the biomedical field.

Pulmonary inhalation for disease treatment: Basic research and clinical translations

Pulmonary drug delivery has the advantages of being rapid, efficient, and well-targeted, with few systemic side effects. In addition, it is non-invasive and has good patient compliance, making it a highly promising drug delivery mode. However, there have been limited studies on drug delivery via pulmonary inhalation compared with oral and intravenous modes. This paper summarizes the basic research and clinical translation of pulmonary inhalation drug delivery for the treatment of diseases and provides insights into the latest advances in pulmonary drug delivery. The paper discusses the processing methods for pulmonary drug delivery, drug carriers (with a focus on various types of nanoparticles), delivery devices, and applications in pulmonary diseases and treatment of systemic diseases (e.g., COVID-19, inhaled vaccines, diagnosis of the diseases, and diabetes mellitus) with an updated summary of recent research advances. Furthermore, this paper describes the applications and recent progress in pulmonary drug delivery for lung diseases and expands the use of pulmonary drugs for other systemic diseases.

Synthetic mRNA delivered to human cells leads to expression of Cpl-1 bacteriophage-endolysin with activity against Streptococcus pneumoniae

Endolysins are bacteriophage-encoded hydrolases that show high antibacterial activity and a narrow substrate spectrum. We hypothesize that an mRNA-based approach to endolysin therapy can overcome some challenges of conventional endolysin therapy, namely organ targeting and bioavailability. We show that synthetic mRNA applied to three human cell lines (HEK293T, A549, HepG2 cells) leads to expression and cytosolic accumulation of the Cpl-1 endolysin with activity against Streptococcus pneumoniae. Addition of a human lysozyme signal peptide sequence translocates the Cpl-1 to the endoplasmic reticulum leading to secretion (hlySP-sCpl-1). The pneumococcal killing effect of hlySP-sCpl-1 was enhanced by introduction of a point mutation to avoid N-linked-glycosylation. hlySP-sCpl-1N215D, collected from the culture supernatant of A549 cells 6 h post-transfection showed a significant killing effect and was active against nine pneumococcal strains. mRNA-based cytosolic Cpl-1 and secretory hlySP-sCpl-1N215D show potential for innovative treatment strategies against pneumococcal disease and, to our best knowledge, represent the first approach to mRNA-based endolysin therapy. We assume that many other bacterial pathogens could be targeted with this novel approach.