Orthogonal Design of Experiments for Engineering of Lipid Nanoparticles for mRNA Delivery to the Placenta

Optimizing Peptide-Conjugated Lipid Nanoparticles for Efficient siRNA Delivery across the Blood-Brain Barrier and Treatment of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is a WHO grade 4 glioma and the most common malignant primary brain tumor. Addressing the clinical management of GBM presents an exceptionally daunting and intricate challenge, particularly in overcoming the blood-brain barrier (BBB) to deliver effective therapies to the brain. Nanotechnology-based drug delivery systems have exhibited considerable promise in tackling this aggressive brain cancer. However, the BBB remains a key challenge in achieving effective brain delivery of nanocarriers. Here, we have optimized a lipid nanoparticle (LNP) formulation (C2) and modified the LNP with Angiopep-2 peptide, which exhibits the most significant improvements in blood-brain barrier penetration and brain accumulation (about 2.23% injection dose). Using the Ang-2-coupled C2 LNP formulation, we researched the therapeutic effect of Polo-like Kinase 1(PLK1)-targeted siRNA delivery to treat a mouse model of GBM. The optimized LNP formulation was demonstrated to significantly inhibit mouse GBM growth and extend the median survival of mice (2.18-fold). This work demonstrates the efficacy of a brain-targeted siRNA delivery system in GBM treatment. As the understanding of the role of RNAs in GBM deepens and innovative delivery methods are continually developed and refined, RNA-based therapies could emerge as a crucial breakthrough in the advancement of brain tumor treatment.

Probing the Role of Lipid Nanoparticle Elasticity on mRNA Delivery to the Placenta

It is well established that the physicochemical properties of lipid nanoparticles (LNPs) can govern their interactions with various biological barriers. One property hypothesized to influence nanoparticle-cell interactions is elasticity. Here, we formulate LNPs with naturally occurring cholesterol analogs to tune LNP elasticity and study its role on mRNA delivery to the placenta. LNP elasticity was measured via atomic force microscopy where these LNPs exhibited Young's moduli ranging from 71.0 ± 26.2 to 411.4 ± 145.7 kPa. In vitro screening of these LNPs in placental trophoblasts showed that stiffer LNPs improved LNP uptake and mRNA delivery compared with softer LNPs. Following intravenous administration to pregnant mice, the stiffer LNPs incorporating β-sitosterol enhanced placental and reduced liver mRNA delivery compared with softer LNPs containing only cholesterol. These results demonstrate the ability of stiffer LNPs to promote placental mRNA delivery and highlight the potential of tuning LNP elasticity to improve LNP-mediated mRNA delivery to organs of interest.

Cytokine mRNA Delivery and Local Immunomodulation in the Placenta using Lipid Nanoparticles

During pregnancy, the maternal immune system adapts to balance tolerance of the semi-allogenic fetus while protecting the fetus from pathogens. Dysregulated immune activity at the maternal-fetal interface contributes to pregnancy complications, such as recurrent pregnancy loss and preeclampsia. Compared to healthy placentas, preeclamptic placentas exhibit increased pro-inflammatory signaling, including a predominance of inflammatory macrophages, leading to impaired tissue remodeling and restricted blood flow. However, the precise mechanisms driving this immune imbalance remain poorly understood, in part due to the lack of tools to probe individual pathways. Here, we use lipid nanoparticles (LNPs) to deliver cytokine-encoded mRNA to placental cells, called trophoblasts, enabling local immunomodulation. LNP-mediated delivery of IL-4 and IL-13 mRNA induced cytokine secretion by trophoblasts, leading to polarization of primary human monocytes toward anti-inflammatory phenotypes. Notably, lowering the mRNA dose increased expression of alternatively-activated macrophage markers, revealing an inverse relationship between dose and polarization status. Intravenous injection of LNPs in pregnant mice achieved placental secretion of IL-4 and IL-13 with minimal changes to pro-inflammatory cytokines in the serum. These findings establish LNPs as a tool for local immunomodulation in the placenta, offering a strategy to study and treat immune dysfunction in pregnancy and in other inflammatory conditions.

Ionizable Cholesterol Analogs as the Fifth Component of Lipid Nanoparticles for Selective Targeting Delivery of mRNA

Lipid nanoparticles (LNP) have shown great promise in clinical applications for delivering mRNA. Targeted delivery of mRNA to particular tissues or organs is essential for precise therapeutic outcomes and minimized side effects in various disease models. However, achieving targeted delivery beyond the liver is a challenge based on current LNP formulations. In this report, we synthesized four ionizable cholesterol analogs by attaching two tertiary amine groups onto the head of a cholesterol-like structure and incorporated them as a fifth component into conventional commercial LNPs based on ALC-0315 or SM-102. Selective targeting delivery of mRNA is achieved by adjusting the proportion of the fifth component in the LNP. Specifically, a spleen-targeted 0315-Ergo-40% formulation demonstrated an impressive 95% delivery efficiency, while a lung-targeted 102-Sito-40% formulation achieved up to 78%. Moreover, when this strategy is applied to a self-developed ionizable lipid named U-101 instead of ALC-0315 or SM-102, the targeting delivery efficiencies to the spleen and lungs reach 96 and 71%, respectively. Multiple assessments suggest that inclusion of the fifth component does not compromise LNP stability, as indicated by consistent particle size, polydispersity index (PDI), and encapsulation efficiency. Furthermore, the test results of liver and kidney function and immunogenicity reveal no increase of toxicity in vivo following the introduction of the fifth component. Additional studies on in vitro cytotoxicity, lysosomal escape, and cellular transfection efficiency confirm that the fifth component does not diminish delivery performance. Taken together, the incorporation of ionizable cholesterol analogs leads to targeting of LNP delivery, which features strong organ selectivity, high safety, and suitability for further evaluation.

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

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

Placenta-tropic VEGF mRNA lipid nanoparticles ameliorate murine pre-eclampsia

Pre-eclampsia is a placental disorder that affects 3-5% of all pregnancies and is a leading cause of maternal and fetal morbidity worldwide1,2. With no drug available to slow disease progression, engineering ionizable lipid nanoparticles (LNPs) for extrahepatic messenger RNA (mRNA) delivery to the placenta is an attractive therapeutic option for pre-eclampsia. Here we use high-throughput screening to evaluate a library of 98 LNP formulations in vivo and identify a placenta-tropic LNP (LNP 55) that mediates more than 100-fold greater mRNA delivery to the placenta in pregnant mice than a formulation based on the Food and Drug Administration-approved Onpattro LNP (DLin-MC3-DMA)3. We propose an endogenous targeting mechanism based on β2-glycoprotein I adsorption that enables LNP delivery to the placenta. In both inflammation- and hypoxia-induced models of pre-eclampsia, a single administration of LNP 55 encapsulating vascular endothelial growth factor (VEGF) mRNA resolves maternal hypertension until the end of gestation. In addition, with our VEGF mRNA LNP 55 therapeutic, we demonstrate improvements in fetal health and partially restore placental vasculature, the local and systemic immune landscape and serum levels of soluble Fms-like tyrosine kinase-1, a clinical biomarker of pre-eclampsia1. Together, these results demonstrate the potential of this mRNA LNP platform for treating placental disorders such as pre-eclampsia.

Strategies for Organ-Targeted mRNA Delivery by Lipid Nanoparticles

Messenger RNA (mRNA) technology has rapidly evolved, significantly impacting various therapeutic applications, including vaccines, protein replacement, and gene editing. Lipid nanoparticles (LNPs) have emerged as a pivotal nonviral vector for mRNA delivery, crucial for organ-targeted therapies. Despite their success, most LNP formulations predominantly target the liver, limiting their use in nonliver diseases. This review explores strategies to achieve organ-specific mRNA delivery using LNPs, including the discovery of new lipid structures, modification of targeting ligands, incorporation of additional components, and optimization of LNP formulations. These advancements aim to enhance the precision and efficacy of mRNA therapeutics across a broader range of diseases.

Influence of ionizable lipid tail length on lipid nanoparticle delivery of mRNA of varying length

RNA-based therapeutics have gained traction for the prevention and treatment of a variety of diseases. However, their fragility and immunogenicity necessitate a drug carrier. Lipid nanoparticles (LNPs) have emerged as the predominant delivery vehicle for RNA therapeutics. An important component of LNPs is the ionizable lipid (IL), which is protonated in the acidic environment of the endosome, prompting cargo release into the cytosol. Currently, there is growing evidence that the structure of IL lipid tails significantly impacts the efficacy of LNP-mediated mRNA translation. Here, we optimized IL tail length for LNP-mediated delivery of three different mRNA cargos. Using C12-200, a gold standard IL, as a model, we designed a library of ILs with varying tail lengths and evaluated their potency in vivo. We demonstrated that small changes in lipophilicity can drastically increase or decrease mRNA translation. We identified that LNPs formulated with firefly luciferase mRNA (1929 base pairs) and C10-200, an IL with shorter tail lengths than C12-200, enhance liver transfection by over 10-fold. Furthermore, different IL tail lengths were found to be ideal for transfection of LNPs encapsulating mRNA cargos of varying sizes. LNPs formulated with erythropoietin (EPO), responsible for stimulating red blood cell production, mRNA (858 base pairs), and the C13-200 IL led to EPO translation at levels similar to the C12-200 LNP. The LNPs formulated with Cas9 mRNA (4521 base pairs) and the C9-200 IL induced over three times the quantity of indels compared with the C12-200 LNP. Our findings suggest that shorter IL tails may lead to higher transfection of LNPs encapsulating larger mRNAs, and that longer IL tails may be more efficacious for delivering smaller mRNA cargos. We envision that the results of this project can be utilized as future design criteria for the next generation of LNP delivery systems for RNA therapeutics.

Flow cytometric analysis of the murine placenta to evaluate nanoparticle platforms during pregnancy

Clinically approved therapeutics for obstetric conditions are extremely limited, with over 80% of drugs lacking appropriate labeling information for pregnant individuals. The pathology for many of these obstetric conditions can be linked to the placenta, necessitating the development of therapeutic platforms for selective drug delivery to the placenta. When evaluating therapeutics for placental delivery, literature has focused on ex vivo delivery to human placental cells and tissue, which can be difficult to source for non-clinical researchers. Evaluating in vivo drug delivery to the placenta using small animal models can be more accessible than using human tissue, but robust, quantitative methods to characterize delivery remain poorly established. Here, we report a flow cytometric method to evaluate in vivo drug delivery to the murine placenta. Specifically, we describe techniques to identify key cell types in the murine placenta - trophoblasts, endothelial cells, and immune cells - via flow cytometric analysis. While we have employed this method to detect lipid nanoparticle-mediated nucleic acid delivery, this approach can extend to a variety of drug carriers (e.g., liposomes, exosomes, polymeric and metallic nanoparticles) and payloads (e.g., small molecules, proteins, other nucleic acids). Similarly, we describe the application of this method toward immunophenotypic analysis to assess changes in the placental immune environment during disease or in response to a therapeutic. Together, the techniques reported herein aim to broaden the accessibility of placental research in an effort to encourage collaboration between physician-scientists, engineers, placental biologists, and clinicians for developing novel therapeutics to treat placental conditions during pregnancy.

In utero delivery of targeted ionizable lipid nanoparticles facilitates in vivo gene editing of hematopoietic stem cells

Monogenic blood diseases are among the most common genetic disorders worldwide. These diseases result in significant pediatric and adult morbidity, and some can result in death prior to birth. Novel ex vivo hematopoietic stem cell (HSC) gene editing therapies hold tremendous promise to alter the therapeutic landscape but are not without potential limitations. In vivo gene editing therapies offer a potentially safer and more accessible treatment for these diseases but are hindered by a lack of delivery vectors targeting HSCs, which reside in the difficult-to-access bone marrow niche. Here, we propose that this biological barrier can be overcome by taking advantage of HSC residence in the easily accessible liver during fetal development. To facilitate the delivery of gene editing cargo to fetal HSCs, we developed an ionizable lipid nanoparticle (LNP) platform targeting the CD45 receptor on the surface of HSCs. After validating that targeted LNPs improved messenger ribonucleic acid (mRNA) delivery to hematopoietic lineage cells via a CD45-specific mechanism in vitro, we demonstrated that this platform mediated safe, potent, and long-term gene modulation of HSCs in vivo in multiple mouse models. We further optimized this LNP platform in vitro to encapsulate and deliver CRISPR-based nucleic acid cargos. Finally, we showed that optimized and targeted LNPs enhanced gene editing at a proof-of-concept locus in fetal HSCs after a single in utero intravenous injection. By targeting HSCs in vivo during fetal development, our Systematically optimized Targeted Editing Machinery (STEM) LNPs may provide a translatable strategy to treat monogenic blood diseases before birth.

Optimized microfluidic formulation and organic excipients for improved lipid nanoparticle mediated genome editing

mRNA-based gene editing platforms have tremendous promise in the treatment of genetic diseases. However, for this potential to be realized in vivo, these nucleic acid cargos must be delivered safely and effectively to cells of interest. Ionizable lipid nanoparticles (LNPs), the most clinically advanced non-viral RNA delivery system, have been well-studied for the delivery of mRNA but have not been systematically optimized for the delivery of mRNA-based CRISPR-Cas9 platforms. In this study, we investigated the effect of microfluidic and lipid excipient parameters on LNP gene editing efficacy. Through in vitro screening in liver cells, we discovered distinct trends in delivery based on phospholipid, cholesterol, and lipid-PEG structure in LNP formulations. Combination of top-performing lipid excipients produced an LNP formulation that resulted in 3-fold greater gene editing in vitro and facilitated 3-fold greater reduction of a therapeutically-relevant protein in vivo relative to the unoptimized LNP formulation. Thus, systematic optimization of LNP formulation parameters revealed a novel LNP formulation that has strong potential for delivery of gene editors to the liver to treat metabolic disease.

Rational design of lipid nanoparticles: overcoming physiological barriers for selective intracellular mRNA delivery

This review introduces the typical delivery process of messenger RNA (mRNA) nanomedicines and concludes that the delivery involves a at least four-step SCER cascade and that high efficiency at every step is critical to guarantee high overall therapeutic outcomes. This SCER cascade process includes selective organ-targeting delivery, cellular uptake, endosomal escape, and cytosolic mRNA release. Lipid nanoparticles (LNPs) have emerged as a state-of-the-art vehicle for in vivo mRNA delivery. The review emphasizes the importance of LNPs in achieving selective, efficient, and safe mRNA delivery. The discussion then extends to the technical and clinical considerations of LNPs, detailing the roles of individual components in the SCER cascade process, especially ionizable lipids and helper phospholipids. The review aims to provide an updated overview of LNP-based mRNA delivery, outlining recent innovations and addressing challenges while exploring future developments for clinical translation over the next decade.

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.

Emerging strategies for nanomedicine in autoimmunity

Autoimmune disorders have risen to be among the most prevalent chronic diseases across the globe, affecting approximately 5-7% of the population. As autoimmune diseases steadily rise in prevalence, so do the number of potential therapeutic strategies to combat them. In recent years, fundamental research investigating autoimmune pathologies has led to the emergence of several cellular targets that provide new therapeutic opportunities. However, key challenges persist in terms of accessing and specifically combating the dysregulated, self-reactive cells while avoiding systemic immune suppression and other off-target effects. Fortunately, the continued advancement of nanomedicines may provide strategies to address these challenges and bring innovative autoimmunity therapies to the clinic. Through precise engineering and rational design, nanomedicines can possess a variety of physicochemical properties, surface modifications, and cargoes, allowing for specific targeting of therapeutics to pathological cell and organ types. These advances in nanomedicine have been demonstrated in cancer therapies and have the broad potential to advance applications in autoimmunity therapies as well. In this review, we focus on leveraging the power of nanomedicine for prevalent autoimmune disorders throughout the body. We expand on three key areas for the development of autoimmunity therapies - avoiding systemic immunosuppression, balancing interactions with the immune system, and elevating current platforms for delivering complex cargoes - and emphasize how nanomedicine-based strategies can overcome these barriers and enable the development of next-generation, clinically relevant autoimmunity therapies.

Lipid nanoparticle structure and delivery route during pregnancy dictate mRNA potency, immunogenicity, and maternal and fetal outcomes

Treating pregnancy-related disorders is exceptionally challenging because the threat of maternal and/or fetal toxicity discourages the use of existing medications and hinders new drug development. One potential solution is the use of lipid nanoparticle (LNP) RNA therapies, given their proven efficacy, tolerability, and lack of fetal accumulation. Here, we describe LNPs for efficacious mRNA delivery to maternal organs in pregnant mice via several routes of administration. In the placenta, our lead LNP transfected trophoblasts, endothelial cells, and immune cells, with efficacy being structurally dependent on the ionizable lipid polyamine headgroup. Next, we show that LNP-induced maternal inflammatory responses affect mRNA expression in the maternal compartment and hinder neonatal development. Specifically, pro-inflammatory LNP structures and routes of administration curtailed efficacy in maternal lymphoid organs in an IL-1β-dependent manner. Further, immunogenic LNPs provoked the infiltration of adaptive immune cells into the placenta and restricted pup growth after birth. Together, our results provide mechanism-based structural guidance on the design of potent LNPs for safe use during pregnancy.

Lipid Nanoparticle (LNP) Delivery Carrier-Assisted Targeted Controlled Release mRNA Vaccines in Tumor Immunity

In recent years, lipid nanoparticles (LNPs) have attracted extensive attention in tumor immunotherapy. Targeting immune cells in cancer therapy has become a strategy of great research interest. mRNA vaccines are a potential choice for tumor immunotherapy, due to their ability to directly encode antigen proteins and stimulate a strong immune response. However, the mode of delivery and lack of stability of mRNA are key issues limiting its application. LNPs are an excellent mRNA delivery carrier, and their structural stability and biocompatibility make them an effective means for delivering mRNA to specific targets. This study summarizes the research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity. The role of LNPs in improving mRNA stability, immunogenicity, and targeting is discussed. This review aims to systematically summarize the latest research progress in LNP delivery carrier-assisted targeted controlled release mRNA vaccines in tumor immunity to provide new ideas and strategies for tumor immunotherapy, as well as to provide more effective treatment plans for patients.

Predictive High-Throughput Platform for Dual Screening of mRNA Lipid Nanoparticle Blood-Brain Barrier Transfection and Crossing

Lipid nanoparticle (LNP)-mediated nucleic acid therapies, including mRNA protein replacement and gene editing therapies, hold great potential in treating neurological disorders including neurodegeneration, brain cancer, and stroke. However, delivering LNPs across the blood-brain barrier (BBB) after systemic administration remains underexplored. In this work, we engineered a high-throughput screening transwell platform for the BBB (HTS-BBB), specifically optimized for screening mRNA LNPs. Unlike most transwell assays, which only assess transport across an endothelial monolayer, HTS-BBB simultaneously measures LNP transport and mRNA transfection of the endothelial cells themselves. We then use HTS-BBB to screen a library of 14 LNPs made with structurally diverse ionizable lipids and demonstrate it is predictive of in vivo performance by validating lead candidates for mRNA delivery to the mouse brain after intravenous injection. Going forward, this platform could be used to screen large libraries of brain-targeted LNPs for a range of protein replacement and gene editing applications.