High-throughput and high-content bioassay enables tuning of polyester nanoparticles for cellular uptake, endosomal escape, and systemic in vivo delivery of mRNA

CRISPR/Cas9 Ribonucleoprotein Delivery Enhanced by Lipo-Xenopeptide Carriers and Homology-Directed Repair Modulators: Insights from Reporter Cell Lines

CRISPR-Cas9 genome editing is a versatile platform for studying and treating various diseases. Homology-directed repair (HDR) with DNA donor templates serves as the primary pathway for gene correction in therapeutic applications, but its efficiency remains a significant challenge. This study investigates strategies to enhance gene correction efficiency using a T-shaped lipo-xenopeptide (XP)-based Cas9 RNP/ssDNA delivery system combined with various HDR enhancers. Nu7441, a known DNA-PKcs inhibitor, was found to be most effective in enhancing HDR-mediated gene correction. An over 10-fold increase in HDR efficiency was achieved by Nu7441 in HeLa-eGFPd2 cells, with a peak HDR efficiency of 53% at a 5 nM RNP concentration and up to 61% efficiency confirmed by Sanger sequencing. Surprisingly, the total gene editing efficiency including non-homologous end joining (NHEJ) was also improved. For example, Nu7441 boosted exon skipping via NHEJ-mediated splice site destruction by 30-fold in a DMD reporter cell model. Nu7441 modulated the cell cycle by reducing cells in the G1 phase and extending the S and G2/M phases without compromising cellular uptake or endosomal escape. The enhancement in genome editing by Nu7441 was widely applicable across several cell lines, several Cas9 RNP/ssDNA carriers (LAF-XPs), and also Cas9 mRNA/sgRNA/ssDNA polyplexes. These findings highlight a novel and counterintuitive role for Nu7441 as an enhancer of both HDR and total gene editing efficiency, presenting a promising strategy for Cas9 RNP-based gene therapy.

Multipronged SMAD pathway targeting by lipophilic poly(β-amino ester) miR-590-3p nanomiRs inhibits mesenchymal glioblastoma growth and prolongs survival

ASBSTRACT

Despite aggressive therapy, glioblastoma (GBM) recurs in almost all patients and treatment options are very limited. Despite our growing understanding of how cellular transitions associate with relapse in GBM, critical gaps remain in our ability to block these molecular changes and treat recurrent disease. In this study we combine computational biology, forward-thinking understanding of miRNA biology and cutting-edge nucleic acid delivery vehicles to advance targeted therapeutics for GBM. Computational analysis of RNA sequencing from clinical GBM specimens identified TGFβ type II receptor (TGFBR2) as a key player in the mesenchymal transition associated with worse outcome in GBM. Mechanistically, we show that elevated levels of TGFBR2 is conducive to reduced temozolomide (TMZ) sensitivity. This effect is, at least partially, induced by stem-cell driving events coordinated by the reprogramming transcription factors Oct4 and Sox2 that lead to open chromatin states. We show that blocking TGFBR2 via molecular and pharmacological approaches decreases stem cell capacity and sensitivity of clinical recurrent GBM (rGBM) isolates to TMZ in vitro. Network analysis uncovered miR-590-3p as a tumor suppressor that simultaneously inhibits multiple oncogenic nodes downstream of TGFBR2. We also developed novel biodegradable lipophilic poly(β-amino ester) nanoparticles (LiPBAEs) for in vivo microRNA (miRNAs) delivery. Following direct intra-tumoral infusion, these nanomiRs efficiently distribute through the tumors. Importantly, miR-590-3p nanomiRs inhibited the growth and extended survival of mice bearing orthotopic human rGBM xenografts, with an apparent 30% cure rate. These results show that miRNA-based targeted therapeutics provide new opportunities to treat rGBM and bypass the resistance to standard of care therapy.

Hydrogen-induced disruption of the airway mucus barrier enhances nebulized RNA delivery to reverse pulmonary fibrosis

Nebulized RNA therapies are well suited for treating respiratory diseases, in particular pulmonary fibrosis (PF); however, effective delivery remains challenging. In this study, we present a highly efficient aerosol inhalation system that enables high levels of in vivo transfection efficiency in lung macrophages, yielding durable responses against PF. First, we established a nose-only aerosol inhalation device integrated with a hydrogen supplement system. This setup enables the precise administration of lipid nanoparticles (LNPs) at a controlled low dose, while simultaneously delivering the optimal concentration of therapeutic hydrogen gas. We further developed a hybrid lipid NP (HNP) by hybridizing a pH-dependent charge-inverting lipid film with apoptotic T cell membranes to enhance endosomal escape and trigger macrophage production of hepatocyte growth factor for lung repair. We demonstrated that the hydrogen flow-induced shear stresses disrupt the NP-mucus interaction, enhancing the deposition of aerosolized HNPs/TGFβ1 siRNA within fibrotic lung lesions, effectively blocking fibrogenic signaling pathways and offering a clinically viable strategy for combating PF.

Modular Calcium-Responsive and CD9-Targeted Phospholipase System Enhancing Endosomal Escape for DNA Delivery

Gene delivery systems must overcome multiple barriers, with endosomal escape representing a prominent obstacle. We have previously shown that a bacterial phospholipase C (PLC) enabled endosomal escape of a non-viral protein-based DNA delivery system termed TFAMoplex. Building upon this, this work introduces a calcium-responsive system designed to enhance endosomal escape through non-covalent capturing of PLC to the TFAMoplex followed by its release within endosomes and nanobody-mediated targeting to the endosomal membrane. This approach leads to improved TFAMoplexes enabling transfection of HeLa cells in full serum with a half maximal effective concentration (EC50) of less than 200 ng DNA per mL serum, using only 5 nM PLC. Particularly, the modular capture, release and targeting system could potentially be adapted to other delivery agents previously constrained by poor endosomal escape. These findings present a promising strategy to achieve efficient endosomal escape, offering prospects for improved delivery of macromolecules, in particular nucleic acids.

Lung-Specific mRNA Delivery by Ionizable Lipids with Defined Structure-Function Relationship and Unique Protein Corona Feature

Targeted delivery of mRNA with lipid nanoparticles (LNPs) holds great potential for treating pulmonary diseases. However, the lack of rational design principles for efficient lung-homing lipids hinders the prevalence of mRNA therapeutics in this organ. Herein, the combinatorial screening with structure-function analysis is applied to rationalize the design strategy for nonpermanently charged lung-targeted ionizable lipids. It is discovered that lipids carrying N-methyl and secondary amine groups in the heads, and three tails originated from epoxyalkanes, exhibiting superior pulmonary selectivity and efficiency. Representative ionizable lipids with systematically variation in chemical structures are selected to study the well-known but still puzzling "protein corona" adsorbed on the surface of LNPs. In addition to the commonly used corona-biomarker vitronectin, other arginine-glycine-aspartic acid (RGD)-rich proteins usually involved in collagen-containing extracellular matrix, such as fibrinogen and fibronectin have also been identified to have a strong correlation with lung tropism. This work provides insight into the rational design of lung-targeting ionizable lipids and reveals a previously unreported potential function of RGD-rich proteins in the protein corona of lung-homing LNPs.

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.

Revolutionizing mRNA Vaccines Through Innovative Formulation and Delivery Strategies

Modernization of existing methods for the delivery of mRNA is vital in advanced therapeutics. Traditionally, mRNA has faced obstacles of poor stability due to enzymatic degradation. This work examines cutting-edge formulation and emerging techniques for safer delivery of mRNA vaccines. Inspired by the success of lipid nanoparticles (LNP) in delivering mRNA vaccines for COVID-19, a variety of other formulations have been developed to deliver mRNA vaccines for diverse infections. The meritorious features of nanoparticle-based mRNA delivery strategies, including LNP, polymeric, dendrimers, polysaccharide-based, peptide-derived, carbon and metal-based, DNA nanostructures, hybrid, and extracellular vesicles, have been examined. The impact of these delivery platforms on mRNA vaccine delivery efficacy, protection from enzymatic degradation, cellular uptake, controlled release, and immunogenicity has been discussed in detail. Even with significant developments, there are certain limitations to overcome, including toxicity concerns, limited information about immune pathways, the need to maintain a cold chain, and the necessity of optimizing administration methods. Continuous innovation is essential for improving delivery systems for mRNA vaccines. Future research directions have been proposed to address the existing challenges in mRNA delivery and to expand their potential prophylactic and therapeutic application.

Accelerated Endosomal Escape of Splice-Switching Oligonucleotides Enables Efficient Hepatic Splice Correction

Splice-switching oligonucleotides (SSOs) can restore protein functionality in pathologies and are promising tools for manipulating the RNA-splicing machinery. Delivery vectors can considerably improve SSO functionality in vivo and allow dose reduction, thereby addressing the challenges of RNA-targeted therapeutics. Here, we report a biocompatible SSO nanocarrier, based on redox-responsive disulfide cross-linked low-molecular-weight linear polyethylenimine (cLPEI), for overcoming multiple biological barriers from subcellular compartments to en-route serum stability and finally in vivo delivery challenges. Intracellularly responsive cross-links of cLPEI significantly accelerated the endosomal escape and offered efficient SSO release to the cell's nucleus, thereby leading to high splice correction in vitro. In vivo performance of cLPEI-SSOs was investigated in a novel transgenic mouse model for splice correction, spatiotemporal tracking of SSO delivery in wild-type mice, and biodistribution in a colorectal cancer peritoneal metastasis model. A single intravenous application of 5 mg kg-1 cLPEI-SSOs induced splice correction in liver, lung, kidney, and bladder, giving functional protein, which was validated by RT-PCR. Near-infrared (NIR) fluorescence imaging and X-ray computed tomography revealed improved organ retention and reduced renal excretion of SSOs. NIR microscopy demonstrated the accumulation of SSOs in angiogenic tumors within the pancreas. Successful nuclear delivery of SSOs was observed in the hepatocytes. Thus, cLPEI nanocarriers resulted in highly efficient splice correction in vivo, highlighting the critical role of the enhanced SSO bioavailability.

Loading of Extracellular Vesicles with Nucleic Acids via Hybridization with Non-Lamellar Liquid Crystalline Lipid Nanoparticles

The translation of cell-derived extracellular vesicles (EVs) into biogenic gene delivery systems is limited by relatively inefficient loading strategies. In this work, the loading of various nucleic acids into small EVs via their spontaneous hybridization with preloaded non-lamellar liquid crystalline lipid nanoparticles (LCNPs), forming hybrid EVs (HEVs) is described. It is demonstrated that LCNPs undergo pH-dependent structural transitions from inverse hexagonal (HII) phases at pH 5 to more disordered non-lamellar phases, possibly inverse micellar (L2) or sponge (L3) phases, at pH 7.4, which are particularly suitable for inducing a controlled hybridization process with EVs. State-of-the-art single-particle analysis techniques reveal that LCNPs interact with various EV subpopulations at physiological conditions and that ≈40% of HEVs are loaded with the genetic cargo. Importantly, this study demonstrates that EV membrane proteins remain accessible on HEV surfaces, with their intrinsic enzymatic activity unaffected after the hybridization process. Finally, HEVs show in vitro improved transfection efficiencies compared to unhybridized LCNPs. In summary, this versatile platform holds potential for loading various nucleic acid molecules into native EVs and may help developing EV-based therapeutics.

Advanced Polymeric Nanoparticles for Cancer Immunotherapy: Materials Engineering, Immunotherapeutic Mechanism and Clinical Translation

Cancer immunotherapy, which leverages immune system components to treat malignancies, has emerged as a cornerstone of contemporary therapeutic strategies. Yet, critical concerns about the efficacy and safety of cancer immunotherapies remain formidable. Nanotechnology, especially polymeric nanoparticles (PNPs), offers unparalleled flexibility in manipulation-from the chemical composition and physical properties to the precision control of nanoassemblies. PNPs provide an optimal platform to amplify the potency and minimize systematic toxicity in a broad spectrum of immunotherapeutic modalities. In this comprehensive review, the basics of polymer chemistry, and state-of-the-art designs of PNPs from a physicochemical standpoint for cancer immunotherapy, encompassing therapeutic cancer vaccines, in situ vaccination, adoptive T-cell therapies, tumor-infiltrating immune cell-targeted therapies, therapeutic antibodies, and cytokine therapies are delineated. Each immunotherapy necessitates distinctively tailored design strategies in polymeric nanoplatforms. The extensive applications of PNPs, and investigation of their mechanisms of action for enhanced efficacy are particularly focused on. The safety profiles of PNPs and clinical research progress are discussed. Additionally, forthcoming developments and emergent trends of polymeric nano-immunotherapeutics poised to transform cancer treatment paradigms into clinics are explored.

Dual pH-responsive CRISPR/Cas9 ribonucleoprotein xenopeptide complexes for genome editing

Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated (Cas) protein has been proved as a powerful tool for the treatment of genetic diseases. The Cas9 protein, when combined with single-guide RNA (sgRNA), forms a Cas9/sgRNA ribonucleoprotein (RNP) capable of targeting and editing the genome. However, the limited availability of effective carriers has restricted the broader application of CRISPR/Cas9 RNP. In this study, we evaluated dual pH-responsive amphiphilic xenopeptides (XPs) for delivering CRISPR/Cas9 RNP. These artificial lipo-XPs contain apolar cationizable lipoamino fatty acid (LAF) and polar cationizable oligoaminoethylene acid units such as succinoyl-tetraethylenepentamine (Stp) in various ratios and U-shaped topologies. The carriers were screened for functional Cas9/sgRNA RNP delivery in four different reporter cell lines, including a Duchenne muscular dystrophy (DMD) exon skipping reporter cell model. Significantly enhanced cellular uptake into HeLa cells, effective endosomal disruption in HeLa gal8-mRuby3 cells, and potent genome editing by several Cas9/sgRNA RNP complexes was observed in four different cell lines in the 5 nM sgRNA range. Comparing Cas9/sgRNA RNP complexes with Cas9 mRNA/sgRNA polyplexes in the DMD reporter cell model demonstrated similar splice site editing and high exon skipping of the two different molecular Cas9 modalities. Based on these studies, analogues of two potent U1 LAF2-Stp and LAF4-Stp2 structures were deployed, tuning the amphiphilicity of the polar Stp group by replacement with the six oligoamino acids dmGtp, chGtp, dGtp, Htp, Stt, or GEIPA. The most potent LAF2-Stp analogues (containing dGtp, chGtp or GEIPA) demonstrated further enhanced gene editing efficiency with EC50 values of 1 nM in the DMD exon skipping reporter cell line. Notably, the EC50 of LAF2-dGtp reached 0.51 nM even upon serum incubation. Another carrier (LAF4-GEIPA2) complexing Cas9/sgRNA RNP and donor DNA, facilitated up to 43 % of homology-directed repair (HDR) in HeLa eGFPd2 cells visualized by the switch from green fluorescent protein (eGFP) to blue fluorescent protein (BFP). This study presents a delivery system tunable for Cas9 RNP complexes or Cas9 RNP/donor DNA polyplexes, offering an effective and easily applicable strategy for gene editing.

RNA therapies for musculoskeletal conditions

Musculoskeletal conditions impact 1.71 billion individuals, posing significant challenges due to their complexity, varying clinical courses, and unclear molecular mechanisms. Conventional spectrum treatments often prove inadequate, underscoring the importance of targeted therapies. Recently, RNA-based technologies have emerged as a groundbreaking approach in therapeutics, showing applications in joint related ailments. This perspective aims to examine endeavors exploring the use of RNA-based treatments in both experimental and clinical contexts for addressing joint issues like osteoarthritis, rheumatoid arthritis, and cartilage injuries. The cited studies demonstrate how mRNA can stimulate the production of proteins that aid in controlling inflammation, fostering tissue regeneration and repairing cartilage damage. In summary, this perspective offers an overview of the progress made in mRNA-based technologies for treating related conditions by highlighting favorable findings from preclinical research and encouraging results from clinical trials. With advancements in the field, mRNA therapeutics have the potential to revolutionize treatment approaches for musculoskeletal disorders, bringing renewed hope to the future of musculoskeletal conditions.

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.

Polymers for mRNA Delivery

mRNA delivery has emerged as a transformative approach in biotechnology and medicine, offering a versatile platform for the development of novel therapeutics. Unlike traditional small molecule drugs or protein-based biologics, mRNA therapeutics have the unique ability to direct cells to generate therapeutic proteins, allowing for precise modulation of biological processes. The delivery of mRNA into target cells is a critical step in realizing the therapeutic potential of this technology. In this review, our focus is on the latest advancements in designing functional polymers to achieve efficient mRNA delivery. Biodegradable polymers and low molecular weight polymers in addressing the balance in mRNA binding and release are summarized. Benefiting from the excellent performance of lipid nanoparticles in mRNA delivery, polymer/lipid hybrid nanostructures are also included. Finally, the challenges and future prospects in the development of polymer-based mRNA delivery systems are discussed.

Suprachoroidal Delivery of Viral and Nonviral Vectors for Treatment of Retinal and Choroidal Vascular Diseases

PURPOSE

Current treatments for retinal and choroidal neovascular diseases suffer from insufficient durability, including anti-vascular endothelial growth factor-A agents. It is, therefore, of interest to explore alternative methods that could allow for robust improvement in visual acuity with fewer injections required.

DESIGN

Literature review.

RESULTS

Among various preclinical and clinical studies in the literature, a promising approach is the use of suprachoroidal injection with viral and nonviral gene delivery vectors. Compared with other ocular injection methods, suprachoroidal injection has demonstrated wide biodistribution of injected agents and safety as an outpatient procedure. In terms of viral vectors, suprachoroidal injection of an adeno-associated virus 8 vector expressing an anti-vascular endothelial growth factor-A antibody fragment has shown an excellent safety profile and evidence of biological activity. In terms of nonviral vectors, lipid nanoparticles and polymeric nanoparticles both demonstrate strong promise for ocular gene therapy in large animal models. In particular, biodegradable poly(β-amino ester) nanoparticles show excellent biodistribution, safety, and efficacy for gene therapy via the suprachoroidal route. Nonviral nanoparticle approaches can have notable advantages over viral vectors in terms of carrying capacity, redosability, and manufacturing costs. An advantage of gene therapy is that once a delivery vector has been optimized, genetic cargos can be readily tailored without changing the safety, efficacy, and pharmacokinetic properties of the delivery vector.

CONCLUSIONS

This review highlights recent progress that has been made and compares viral and nonviral suprachoroidal gene delivery for the treatment of retinal and choroidal vascular diseases. Suprachoroidal gene therapy is an emerging biotechnology that holds substantial potential to make a translational impact in treating these diseases.

Cell membrane-coated mRNA nanoparticles for enhanced delivery to dendritic cells and immunotherapy

Cationic polymers such as polyethylenimine have been considered promising carriers for mRNA vaccines. However, their application is hindered by their inherent toxicity and a lack of targeted delivery capability. These issues need to be addressed to develop effective cancer vaccines. In this study, we investigated whether dendritic cell membrane-coated polyethylenimine/mRNA nanoparticles (DPN) could effectively deliver mRNA to dendritic cells and induce immune responses. For comparison, we employed red blood cell membrane-coated polyethylenimine/mRNA (RPN) and plain polyethylenimine/mRNA polyplex (PN). The dendritic cell membrane coating altered the zeta potential values and surface protein patterns of PN. DPN demonstrated significantly higher uptake in dendritic cells compared to PN and RPN, and it also showed greater mRNA expression within these cells. DPN, carrying mRNA encoding luciferase, enhanced green fluorescent protein, or ovalbumin (OVA), exhibited higher protein expression in dendritic cells than the other groups. Additionally, DPN exhibited favorable mRNA escape from lysosomes post-internalization into dendritic cells. In mice, subcutaneous administration of DPN containing ovalbumin mRNA (DPNOVA) elicited higher titers of anti-OVA IgG antibodies and a greater population of OVA-specific CD8+ T cells than the other groups. In a B16F10-OVA tumor model, DPNOVA treatment resulted in the lowest tumor growth among the treated groups. Moreover, the population of OVA-specific CD8+ T cells was the highest in the DPNOVA-treated group. While we demonstrated DPN's feasibility as an mRNA delivery system in a tumor model, the potential of DPN can be broadly extended for immunotherapeutic treatments of various diseases through mRNA delivery to antigen-presenting cells.

Production of site-specific antibody conjugates using metabolic glycoengineering and novel Fc glycovariants

Molecular conjugation to antibodies has emerged as a growing strategy to combine the mechanistic activities of the attached molecule with the specificity of antibodies. A variety of technologies have been applied for molecular conjugation; however, these approaches face several limitations, including disruption of antibody structure, destabilization of the antibody, and/or heterogeneous conjugation patterns. Collectively, these challenges lead to reduced yield, purity, and function of conjugated antibodies. While glycoengineering strategies have largely been applied to study protein glycosylation and manipulate cellular metabolism, these approaches also harbor great potential to enhance the production and performance of protein therapeutics. Here, we devise a novel glycoengineering workflow for the development of site-specific antibody conjugates. This approach combines metabolic glycoengineering using azido-sugar analogs with newly installed N-linked glycosylation sites in the antibody constant domain to achieve specific conjugation to the antibody via the introduced N-glycans. Our technique allows facile and efficient manufacturing of well-defined antibody conjugates without the need for complex or destructive chemistries. Moreover, the introduction of conjugation sites in the antibody fragment crystallizable (Fc) domain renders this approach widely applicable and target agnostic. Our platform can accommodate up to three conjugation sites in tandem, and the extent of conjugation can be tuned through the use of different sugar analogs or production in different cell lines. We demonstrated that our platform is compatible with various use-cases, including fluorescent labeling, antibody-drug conjugation, and targeted gene delivery. Overall, this study introduces a versatile and effective yet strikingly simple approach to producing antibody conjugates for research, industrial, and medical applications.

Efficient Polymeric Nanoparticle Gene Delivery Enabled Via Tri- and Tetrafunctional Branching

Poly(β-amino ester) (PBAE) nanoparticles (NPs) show great promise for nonviral gene delivery. Recent studies suggest branched PBAEs (BPBAEs) offer advantages over linear counterparts, but the effect of polymer structure has not been well investigated across many chemical constituents. Here, a library of BPBAEs was synthesized with tri- and tetrafunctional branching. These polymers self-assemble with DNA to form highly cationic, monodisperse NPs with notably small size (∼50 nm). Optimal transfection occurred with polymer structures that featured moderate PBAE branching, enabling complete DNA encapsulation, rapid NP uptake, and robust expression at low DNA doses and polymer amounts. Optimized NPs enabled efficient DNA delivery to diverse cell types in vitro while maintaining high cellular viability, demonstrating significant improvements over a well-performing linear PBAE counterpart. BPBAEs also facilitated efficient mRNA and siRNA delivery, highlighting the versatility of these structures and demonstrating the broad utility of BPBAE NPs as vectors for nucleic acid delivery.

The CCR6-CCL20 Axis Promotes Regulatory T-cell Glycolysis and Immunosuppression in Tumors

Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity toward CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wild-type mice and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity.

Therapeutic potential and impact of nanoengineered patient-derived mesenchymal stem cells in a murine resection and recurrence model of human glioblastoma

Confounding results of engineered mesenchymal stem cells (MSCs) used as cellular vehicles has plagued technologies whereby success or failure of novel approaches may be dismissed or inaccurately ascribed solely to the biotechnology platform rather than suitability of the human donor. Polymeric materials were screened for non-viral engineering of MSCs from multiple human donors to deliver bone morphogenic protein-4 (BMP4), a protein previously investigated in clinical trials for glioblastoma (GBM) to combat a subpopulation of highly invasive and tumorigenic clones. A "smart technology" that target the migratory and stem-like nature of GBM will require: (1) a cellular vehicle (MSC) which can scavenge and target residual cells left behind after surgical debulking and deliver; (2) anti-glioma cargo (BMP4). Multiple MSC donors are safely engineered, though varied in susceptibility to accept BMP4 due to intrinsic characteristics revealed by their molecular signatures. Efficiency is compared via secretion, downstream signaling, differentiation, and anti-proliferative properties across all donors. In a clinically relevant resection and recurrence model of patient-derived human GBM, we demonstrate that nanoengineered MSCs are not "donor agnostic" and efficacy is influenced by the inherent suitability of the MSC to the cargo. Therefore, donor profiles hold greater influence in determining downstream outcomes than the technical capabilities of the engineering technology.

Unraveling mRNA delivery bottlenecks of ineffective delivery vectors by co-transfection with effective carriers

The messenger RNA (mRNA) SARS-CoV-2 vaccines have demonstrated the therapeutic potential of this novel drug modality. Protein expression is the consequence of a multistep delivery process that relies on proper packaging into nanoparticle carriers to protect the mRNA against degradation enabling effective cellular uptake and endosomal release, and liberating the mRNA in the cytosol. Bottlenecks along this route remain challenging to pinpoint. Although methods to assess endosomal escape of carriers have been developed, versatile strategies to identify bottlenecks along the delivery trajectory are missing. Here, it is shown that co-incubating an inefficient nanoparticle formulation with an efficient one solves this problem. Cells were co-incubated with mRNA nanoparticles formed with either the efficient cell-penetrating peptide (CPP) PepFect14 or the inefficient CPP nona-arginine (R9). Co-transfection enhanced cellular uptake and endosomal escape of R9-formulated mRNA, resulting in protein expression, demonstrating that both vectors enter cells along the same route. In addition, cells were transfected with a galectin-9-mCherry fusion protein to detect endosomal rupture. Remarkably, despite endosomal release, mRNA remained confined to punctate structures, identifying mRNA liberation as a further bottleneck. In summary, co-transfection offers a rapid means to identify bottlenecks in cytosolic mRNA delivery, supporting the rational design and optimization of intracellular mRNA delivery systems.

Supramolecular assembly of polycation/mRNA nanoparticles and in vivo monocyte programming

Size-dependent phagocytosis is a well-characterized phenomenon in monocytes and macrophages. However, this size effect for preferential gene delivery to these important cell targets has not been fully exploited because commonly adopted stabilization methods for electrostatically complexed nucleic acid nanoparticles, such as PEGylation and charge repulsion, typically arrest the vehicle size below 200 nm. Here, we bridge the technical gap in scalable synthesis of larger submicron gene delivery vehicles by electrostatic self-assembly of charged nanoparticles, facilitated by a polymer structurally designed to modulate internanoparticle Coulombic and van der Waals forces. Specifically, our strategy permits controlled assembly of small poly(β-amino ester)/messenger ribonucleic acid (mRNA) nanoparticles into particles with a size that is kinetically tunable between 200 and 1,000 nm with high colloidal stability in physiological media. We found that assembled particles with an average size of 400 nm safely and most efficiently transfect monocytes following intravenous administration and mediate their differentiation into macrophages in the periphery. When a CpG adjuvant is co-loaded into the particles with an antigen mRNA, the monocytes differentiate into inflammatory dendritic cells and prime adaptive anticancer immunity in the tumor-draining lymph node. This platform technology offers a unique ligand-independent, particle-size-mediated strategy for preferential mRNA delivery and enables therapeutic paradigms via monocyte programming.

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.

Strategies and mechanisms for endosomal escape of therapeutic nucleic acids

Despite impressive recent establishment of therapeutic nucleic acids as drugs and vaccines, their broader medical use is impaired by modest performance in intracellular delivery. Inefficient endosomal escape presents a major limitation responsible for inadequate cytosolic cargo release. Depending on the carrier, this endosomal barrier can strongly limit or even abolish nucleic acid delivery. Different recent endosomal escape strategies and their hypothesized mechanisms are reviewed.

Modulating efficacy and cytotoxicity of lipoamino fatty acid nucleic acid carriers using disulfide or hydrophobic spacers

Double pH-responsive xenopeptides comprising polar ionizable succinoyl tetraethylene pentamine (Stp) motifs and lipophilic ionizable lipoamino fatty acids (LAFs) were recently found to efficiently transfect mRNA and pDNA at low doses. However, potency was often accompanied with cytotoxicity at higher doses. Insertion of bioreducible disulfide building blocks (ssbb) or non-reducible hydrophobic spacers between polar and apolar ionizable domains of LAF-Stp carriers should mitigate toxicity of xenopeptides. Carriers showed stable nucleic acid complexation and endosomal pH-dependent lytic activities, both of which were abolished after reductive cleavage of ssbb-containing carriers. For pDNA, U-shaped carriers with one Stp and two LAF units or bundle carriers with two Stps and four LAFs displayed highest potency. For mRNA, best transfection was achieved with bundle carriers with one Stp and four LAFs. Both the ssbb and hydrophobic spacer containing analogs displayed improved metabolic activity, reduced membrane damage, and improved cell growth. The ssbb carriers were most beneficial regarding living cell count and low apoptosis rates. Mechanistically, inserted spacers decelerated the transfection kinetics and altered the requirement of endosomal protonation. Overall, mRNA and pDNA carriers with improved biocompatibility have been designed, with their high potency illustrated in transfection of various cell lines including low passage number colon carcinoma cells.

Design of Experiments Grants Mechanistic Insights into the Synthesis of Spermine-Containing PBAE Copolymers

Successful therapeutic delivery of siRNA with polymeric nanoparticles seems to be a promising but not vastly understood and complicated goal to achieve. Despite years of research, no polymer-based delivery system has been approved for clinical use. Polymers, as a delivery system, exhibit considerable complexity and variability, making their consistent production a challenging endeavor. However, a better understanding of the polymerization process of polymer excipients may improve the reproducibility and material quality for more efficient use in drug products. Here, we present a combination of Design of Experiment and Python-scripted data science to establish a prediction model, from which important parameters can be extracted that influence the synthesis results of polybeta-amino esters (PBAEs), a common type of polymer used preclinically for nucleic acid delivery. We synthesized a library of 27 polymers, each one at different temperatures with different reaction times and educt ratios using an orthogonal central composite (CCO-) design. This design allowed a detailed characterization of factor importance and interactions using a very limited number of experiments. We characterized the polymers by analyzing the resulting composition by 1H-NMR and the size distribution by GPC measurements. To further understand the complex mechanism of block polymerization in a one-pot synthesis, we developed a Python script that helps us to understand possible step-growth steps. We successfully developed and validated a predictive response surface and gathered a deeper understanding of the synthesis of polyspermine-based amphiphilic PBAEs.

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.

Mitochondrial DNA-boosted dendritic cell-based nanovaccination triggers antitumor immunity in lung and pancreatic cancers

Low migratory dendritic cell (DC) levels pose a challenge in cancer immune surveillance, yet their impact on tumor immune status and immunotherapy responses remains unclear. We present clinical evidence linking reduced migratory DC levels to immune-cold tumor status, resulting in poor patient outcomes. To address this, we develop an autologous DC-based nanovaccination strategy using patient-derived organoid or cancer cell lysate-pulsed cationic nanoparticles (cNPs) to load immunogenic DC-derived microvesicles (cNPcancer cell@MVDC). This approach transforms immune-cold tumors, increases migratory DCs, activates T cells and natural killer cells, reduces tumor growth, and enhances survival in orthotopic pancreatic and lung cancer models, surpassing conventional methods. In vivo imaging reveals superior cNPcancer cell@MVDC accumulation in tumors and lymph nodes, promoting immune cell infiltration. Mechanistically, cNPs enrich mitochondrial DNA, enhancing cGAS-STING-mediated DC activation and migration. Our strategy shifts cold tumors to a hot state, enhancing antitumor immunity for potential personalized cancer treatments.

A Lung-Expressing mRNA Delivery Platform with Tunable Activity in Hypoxic Environments

Messenger RNA (mRNA) delivery platforms often facilitate protein expression in the liver following intravenous injection and have been optimized for use in normally oxygenated cells (21% O2 atmosphere). However, there is a growing need for mRNA therapy in diseases affecting non-liver organs, such as the lungs. Additionally, many diseases are characterized by hypoxia (<21% O2 atmosphere), a state of abnormally low oxygenation in cells and tissues that can reduce the efficacy of mRNA therapies by upwards of 80%. Here, we report a Tunable Lung-Expressing Nanoparticle Platform (TULEP) for mRNA delivery, whose properties can be readily tuned for optimal expression in hypoxic environments. Briefly, our study begins with the synthesis and characterization of a novel amino acrylate polymer that can be effectively complexed with mRNA payloads into TULEPs. We study the efficacy and mechanism of mRNA delivery using TULEP, including analysis of the cellular association, endocytosis mechanisms, endosomal escape, and protein expression in a lung cell line. We then evaluate TULEP under hypoxic conditions and address hypoxia-related deficits in efficacy by making our system tunable with adenosine triphosphate (ATP). Finally, we conclude our study with an in vivo analysis of mRNA expression, biodistribution, and tolerability of the TULEP platform in mice. In presenting these data, we hope that our work highlights the utility of TULEPs for tunable and effective mRNA delivery while more broadly highlighting the utility of considering oxygen levels when developing mRNA delivery platforms.

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

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

Leveraging high-throughput screening technologies in targeted mRNA delivery

Messenger ribonucleic acid (mRNA) has emerged as a promising molecular preventive and therapeutic approach that opens new avenues for healthcare. Although the use of delivery systems, especially lipid nanoparticles (LNPs), greatly improves the efficiency and stability of mRNA, mRNA tends to accumulate in the liver and hardly penetrates physiological barriers to reach the target site after intravenous injection. Hence, the rational design of targeting strategies aimed at directing mRNA to specific tissues and cells remains an enormous challenge in mRNA therapy. High-throughput screening (HTS) is a cutting-edge targeted technique capable of synthesizing chemical compound libraries for the large-scale experiments to validate the efficiency of mRNA delivery system. In this review, we firstly provide an overview of conventional low-throughput targeting strategies. Then the latest advancements in HTS techniques for mRNA targeted delivery, encompassing optimizing structures of large-scale delivery vehicles and developing large-scale surface ligands, as well as the applications of HTS techniques in extrahepatic systemic diseases are comprehensively summarized. Moreover, we illustrate the selection of administration routes for targeted mRNA delivery. Finally, challenges in the field and potential solutions to tackle them are proposed, offering insights for future development toward mRNA targeted therapy.

Kinetically Controlled Polyelectrolyte Complex Assembly of microRNA-Peptide Nanoparticles toward Treating Mesothelioma

Broad size distributions and poor long-term colloidal stability of microRNA-carrying nanoparticles, especially those formed by polyelectrolyte complexation, represent major hurdles in realizing their clinical translation. Herein, peptide design is used alongside optimized flash nanocomplexation (FNC) to produce uniform peptide-based miRNA particles of exceptional stability that display anticancer activity against mesothelioma in vitro and in vivo. Modulating the content and display of lysine-based charge from small intrinsically disordered peptides used to complex miRNA proves essential in achieving stable colloids. FNC facilitates kinetic isolation of the mechanistic steps involved in particle formation to allow the preparation of particles of discrete size in a highly reproducible, scalable, and continuous manner, facilitating pre-clinical studies. To the best of the authors knowledge, this work represents the first example of employing FNC to prepare polyelectrolyte complexes of miRNA and peptide. Encapsulation of these particles into an injectable hydrogel matrix allows for their localized in vivo delivery by syringe. A one-time injection of a gel containing particles composed of miRNA-215-5p and the peptide PKM1 limits tumor progression in a xenograft model of mesothelioma.

Polyphenolic Nanoparticle Platforms (PARCELs) for In Vitro and In Vivo mRNA Delivery

Despite their successful implementation in the COVID-19 vaccines, lipid nanoparticles (LNPs) still face a central limitation in the delivery of mRNA payloads: endosomal trapping. Improving upon this inefficiency could afford improved drug delivery systems, paving the way toward safer and more effective mRNA-based medicines. Here, we present polyphenolic nanoparticle platforms (PARCELs) as effective mRNA delivery systems. In brief, our investigation begins with a computationally guided structural analysis of 1825 discrete polyphenolic structural data points across 73 diverse small molecule polyphenols and 25 molecular parameters. We then generate structurally diverse PARCELs, evaluating their in vitro mechanism and activity, ultimately highlighting the superior endosomal escape properties of PARCELs relative to analogous LNPs. Finally, we examine the in vivo biodistribution, protein expression, and therapeutic efficacy of PARCELs in mice. In undertaking this approach, the goal of this study is to establish PARCELs as viable delivery platforms for safe and effective mRNA delivery.

Intelligent Biomaterialomics: Molecular Design, Manufacturing, and Biomedical Applications

Materialomics integrates experiment, theory, and computation in a high-throughput manner, and has changed the paradigm for the research and development of new functional materials. Recently, with the rapid development of high-throughput characterization and machine-learning technologies, the establishment of biomaterialomics that tackles complex physiological behaviors has become accessible. Breakthroughs in the clinical translation of nanoparticle-based therapeutics and vaccines have been observed. Herein, recent advances in biomaterials, including polymers, lipid-like materials, and peptides/proteins, discovered through high-throughput screening or machine learning-assisted methods, are summarized. The molecular design of structure-diversified libraries; high-throughput characterization, screening, and preparation; and, their applications in drug delivery and clinical translation are discussed in detail. Furthermore, the prospects and main challenges in future biomaterialomics and high-throughput screening development are highlighted.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

Optimization of lipid assisted polymeric nanoparticles for siRNA delivery and cancer immunotherapy

To date, five siRNA-based medications have received clinical approval and have demonstrated remarkable therapeutic efficacy in treating various diseases. However, their application has been predominantly limited to liver-specific diseases due to constraints in siRNA delivery capabilities. In this study, we have developed a siRNA delivery system utilizing clinically approved mPEG-b-PLGA, a cationic lipid, and an ionizable lipid. We optimized this system by carefully adjusting their mass ratios, resulting in highly efficient gene silencing. Furthermore, the optimized nanoparticle formulation, which encapsulates siRNA targeting CD47, induces a robust immune response. This response effectively suppresses the progression of melanoma tumors by blocking this critical immune checkpoint.

Lipid-based nanoparticles as drug delivery carriers for cancer therapy

Cancer is a severe disease that results in death in all countries of the world. A nano-based drug delivery approach is the best alternative, directly targeting cancer tumor cells with improved drug cellular uptake. Different types of nanoparticle-based drug carriers are advanced for the treatment of cancer, and to increase the therapeutic effectiveness and safety of cancer therapy, many substances have been looked into as drug carriers. Lipid-based nanoparticles (LBNPs) have significantly attracted interest recently. These natural biomolecules that alternate to other polymers are frequently recycled in medicine due to their amphipathic properties. Lipid nanoparticles typically provide a variety of benefits, including biocompatibility and biodegradability. This review covers different classes of LBNPs, including their characterization and different synthesis technologies. This review discusses the most significant advancements in lipid nanoparticle technology and their use in medicine administration. Moreover, the review also emphasized the applications of lipid nanoparticles that are used in different cancer treatment types.

Recent Progress in the Endosomal Escape Mechanism and Chemical Structures of Polycations for Nucleic Acid Delivery

Nucleic acid-based therapies are seeing a spiralling surge. Stimuli-responsive polymers, especially pH-responsive ones, are gaining widespread attention because of their ability to efficiently deliver nucleic acids. These polymers can be synthesized and modified according to target requirements, such as delivery sites and the nature of nucleic acids. In this regard, the endosomal escape mechanism of polymer-nucleic acid complexes (polyplexes) remains a topic of considerable interest owing to various plausible escape mechanisms. This review describes current progress in the endosomal escape mechanism of polyplexes and state-of-the-art chemical designs for pH-responsive polymers. The importance is also discussed of the acid dissociation constant (i.e., pKa) in designing the new generation of pH-responsive polymers, along with assays to monitor and quantify the endosomal escape behavior. Further, the use of machine learning is addressed in pKa prediction and polymer design to find novel chemical structures for pH responsiveness. This review will facilitate the design of new pH-responsive polymers for advanced and efficient nucleic acid delivery.

Which Lipid Nanoparticle (LNP) Designs Work? A Simple Kinetic Model Linking LNP Chemical Structure to In Vivo Delivery Performance

Although lipid nanoparticles (LNPs) are the predominant nanocarriers for short-interfering RNA (siRNA) delivery, most therapies use nearly identical formulations that have taken 30 years to design but lack the diverse property ranges necessary for versatile application. This dearth in variety and the extended timeline for implementation are attributed to a limited understanding of how LNP properties facilitate overcoming biological barriers. Herein, a simple kinetic model was developed by using major rate-limiting steps for siRNA delivery, and this model enabled the identification of a critical parameter to predict LNP efficacy without extensive experimental testing. A volume-averaged log D, the "solubility" of charged molecules as a function of pH weighted by component volume fractions, resulted in a good correlation between LNP composition and siRNA delivery. Both the effects of modifying the structures of ionizable lipids and LNP composition on gene silencing were easily captured in the model predictions. Thus, this approach provides a robust LNP structure-activity relationship to dramatically accelerate the realization of effective LNP formulations.

Antiangiogenic Therapeutic mRNA Delivery Using Lung-Selective Polymeric Nanomedicine for Lung Cancer Treatment

Therapeutic antibodies that block vascular endothelial growth factor (VEGF) show clinical benefits in treating nonsmall cell lung cancers (NSCLCs) by inhibiting tumor angiogenesis. Nonetheless, the therapeutic effects of systemically administered anti-VEGF antibodies are often hindered in NSCLCs because of their limited distribution in the lungs and their adverse effects on normal tissues. These challenges can be overcome by delivering therapeutic antibodies in their mRNA form to lung endothelial cells, a primary target of VEGF-mediated pulmonary angiogenesis, to suppress the NSCLCs. In this study, we synthesized derivatives of poly(β-amino esters) (PBAEs) and prepared nanoparticles to encapsulate the synthetic mRNA encoding bevacizumab, an anti-VEGF antibody used in the clinic. Optimization of nanoparticle formulations resulted in a selective lung transfection after intravenous administration. Notably, the optimized PBAE nanoparticles were distributed in lung endothelial cells, resulting in the secretion of bevacizumab. We analyzed the protein corona on the lung- and spleen-targeting nanoparticles using proteomics and found distinctive features potentially contributing to their organ-selectivity. Lastly, bevacizumab mRNA delivered by the lung-targeting PBAE nanoparticles more significantly inhibited tumor proliferation and angiogenesis than recombinant bevacizumab protein in orthotopic NSCLC mouse models, supporting the therapeutic potential of bevacizumab mRNA therapy and its selective delivery through lung-targeting nanoparticles. Our proof-of-principle results highlight the clinical benefits of nanoparticle-mediated mRNA therapy in anticancer antibody treatment in preclinical models.

Liter-scale manufacturing of shelf-stable plasmid DNA/PEI transfection particles for viral vector production

The transfection efficiency and stability of the delivery vehicles of plasmid DNA (pDNA) are critical metrics to ensure high-quality and high-yield production of viral vectors. We previously identified that the optimal size of pDNA/poly(ethylenimine) (PEI) transfection particles is 400-500 nm and developed a bottom-up assembly method to construct stable 400-nm pDNA/PEI particles and benchmarked their transfection efficiency in producing lentiviral vectors (LVVs). Here, we report scale-up production protocols for such transfection particles. Using a two-inlet confined impinging jet (CIJ) mixer with a dual syringe pump set-up, we produced a 1-L batch at a flow rate of 100 mL/min, and further scaled up this process with a larger CIJ mixer and a dual peristaltic pump array, allowing for continuous production at a flow rate of 1 L/min without a lot size limit. We demonstrated the scalability of this process with a 5-L lot and validated the quality of these 400-nm transfection particles against the target product profile, including physical properties, shelf and on-bench stability, transfection efficiency, and LVV production yield in both 15-mL bench culture and 2-L bioreactor runs. These results confirm the potential of this particle assembly process as a scalable manufacturing platform for viral vector production.

Recent advances in nanoparticulate RNA delivery systems

Nanoparticle-based RNA delivery has shown great progress in recent years with the approval of two mRNA vaccines for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and a liver-targeted siRNA therapy. Here, we discuss the preclinical and clinical advancement of new generations of RNA delivery therapies along multiple axes. Improvements in cargo design such as RNA circularization and data-driven untranslated region optimization can drive better mRNA expression. New materials discovery research has driven improved delivery to extrahepatic targets such as the lung and splenic immune cells, which could lead to pulmonary gene therapy and better cancer vaccines, respectively. Other organs and even specific cell types can be targeted for delivery via conjugation of small molecule ligands, antibodies, or peptides to RNA delivery nanoparticles. Moreover, the immune response to any RNA delivery nanoparticle plays a crucial role in determining efficacy. Targeting increased immunogenicity without induction of reactogenic side effects is crucial for vaccines, while minimization of immune response is important for gene therapies. New developments have addressed each of these priorities. Last, we discuss the range of RNA delivery clinical trials targeting diverse organs, cell types, and diseases and suggest some key advances that may play a role in the next wave of therapies.

Endosomal escape: A bottleneck for LNP-mediated therapeutics

Lipid nanoparticles (LNPs) have recently emerged as a powerful and versatile clinically approved platform for nucleic acid delivery, specifically for mRNA vaccines. A major bottleneck in the field is the release of mRNA-LNPs from the endosomal pathways into the cytosol of cells where they can execute their encoded functions. The data regarding the mechanism of these endosomal escape processes are limited and contradicting. Despite extensive research, there is no consensus regarding the compartment of escape, the cause of the inefficient escape and are currently lacking a robust method to detect the escape. Here, we review the currently known mechanisms of endosomal escape and the available methods to study this process. We critically discuss the limitations and challenges of these methods and the possibilities to overcome these challenges. We propose that the development of currently lacking robust, quantitative high-throughput techniques to study endosomal escape is timely and essential. A better understanding of this process will enable better RNA-LNP designs with improved efficiency to unlock new therapeutic modalities.

Suprachoroidal gene transfer with nonviral nanoparticles in large animal eyes

Suprachoroidal nonviral gene therapy with biodegradable poly(β-amino ester) nanoparticles (NPs) provides widespread expression in photoreceptors and retinal pigmented epithelial (RPE) cells and therapeutic benefits in rodents. Here, we show in a human-sized minipig eye that suprachoroidal injection of 50 μl of NPs containing 19.2 μg of GFP expression plasmid caused GFP expression in photoreceptors and RPE throughout the entire eye with no toxicity. Two weeks after injection of 50, 100, or 200 μl, there was considerable within-eye and between-eye variability in expression that was reduced 3 months after injection of 200 μl and markedly reduced after three suprachoroidal injections at different locations around the eye. Reduction of bacterial CpG sequences in the expression plasmid resulted in a trend toward higher expression. These data indicate that nonviral suprachoroidal gene therapy with optimized polymer, expression plasmid, and injection approach has potential for treating photoreceptors throughout the entire retina of a human-sized eye.

High-throughput barcoding of nanoparticles identifies cationic, degradable lipid-like materials for mRNA delivery to the lungs in female preclinical models

Lipid nanoparticles for delivering mRNA therapeutics hold immense promise for the treatment of a wide range of lung-associated diseases. However, the lack of effective methodologies capable of identifying the pulmonary delivery profile of chemically distinct lipid libraries poses a significant obstacle to the advancement of mRNA therapeutics. Here we report the implementation of a barcoded high-throughput screening system as a means to identify the lung-targeting efficacy of cationic, degradable lipid-like materials. We combinatorially synthesize 180 cationic, degradable lipids which are initially screened in vitro. We then use barcoding technology to quantify how the selected 96 distinct lipid nanoparticles deliver DNA barcodes in vivo. The top-performing nanoparticle formulation delivering Cas9-based genetic editors exhibits therapeutic potential for antiangiogenic cancer therapy within a lung tumor model in female mice. These data demonstrate that employing high-throughput barcoding technology as a screening tool for identifying nanoparticles with lung tropism holds potential for the development of next-generation extrahepatic delivery platforms.

Sugar alcohol-modified polyester nanoparticles for gene delivery via selective caveolae-mediated endocytosis

Nucleic acid-based drugs are changing the scope of emerging medicine in preventing and treating diseases. Nanoparticle systems based on lipids and polymers developed to navigate tissue-level and cellular-level barriers are now emerging as vector systems that can be translated to clinical settings. A class of polymers, poly(β-amino esters) (PBAEs) known for their chemical flexibility and biodegradability, has been explored for gene delivery. These polymers are sensitive to changes in the monomer composition affecting transfection efficiency. Hence to add functionality to these polymers, we partially substituted ligands to an identified effective polymer chemistry. We report here a new series of statistical copolymers based on PBAEs where the backbone is modified with sugar alcohols to selectively facilitate the caveolae-mediated endocytosis pathway of cellular transport. These ligands are grafted at the polymer's backbone, thereby establishing a new strategy of modification in PBAEs. We demonstrate that these polymers form nanoparticles with DNA, show effective complexation and cargo release, enter the cell via selective caveolae-mediated endocytosis, exhibit low cytotoxicity, and increase transfection in neuronal cells.

Applying artificial intelligence and computational modeling to nanomedicine

Achieving specific and targeted delivery of nanomedicines to diseased tissues is a major challenge. This is because the process of designing, formulating, testing, and selecting a nanoparticle delivery vehicle for a specific disease target is governed by complex multivariate interactions. Computational modeling and artificial intelligence are well-suited for analyzing and modeling large multivariate datasets in short periods of time. Computational approaches can be applied to help design nanomedicine formulations, interpret nanoparticle-biological interactions, and create models from high-throughput screening techniques to improve the selection of the ideal nanoparticle carrier. In the future, many steps in the nanomedicine development process will be done computationally, reducing the number of experiments and time needed to select the ideal nanomedicine formulation.