Amine headgroups in ionizable lipids drive immune responses to lipid nanoparticles by binding to the receptors TLR4 and CD1d

Dual SORT LNPs for multi-organ base editing

Alpha-1 antitrypsin (A1AT) deficiency (AATD) is caused by a mutation in the SERPINA1 gene (PiZ allele), where misfolded A1AT liver accumulation leads to liver damage, and A1AT deficiency in the lungs results in emphysema due to unregulated neutrophil elastase activity. Base editing offers a potential cure for A1AT; however, effective treatment is hindered by the absence of dual-target delivery systems that can target key tissues. We developed Dual Selective ORgan-Targeting lipid nanoparticles (SORT LNPs) to deliver base editors to the liver and lungs. Dual SORT LNPs correct the PiZ mutation, achieving 40% correction editing in liver cells and 10% in lung AT2 cells. The liver maintains stable editing for 32 weeks, reducing Z-A1AT levels by over 80% and restoring a normal liver phenotype. In parallel, 89% neutrophil elastase inhibition is achieved in lung bronchoalveolar lavage fluid. Taken together, Dual SORT LNP therapy offers a promising approach for long-lasting genome correction for multi-organ diseases such as AATD.

Golden insights for exploring cancer: delivery, from genes to the human body using bimetallic Au/Ag nanostructures

Sweeping contact with cancer continues to rise globally, which has led to advanced research on new treatment approaches; nanotechnology has become crucial to targeted cancer therapy. Within the intimate of nanomaterials, Au/Ag nanostructures have emerged as highly attractive because of their distinctive desirable characteristics and their prospective roles in diagnosis as well as cancer therapy. The nanostructures developed revealed remarkable biocompatibility, optically recursive alteration, and magnificently improved therapeutic effects of gold and silver in conjunction with each other. This review addresses the molecular and systemic aspects of Au/Ag nanostructures in cancer research, including the impact of nanostructures on the molecular genetic pathways and their use of systemic administration in the human organism. We explain some of the related mechanisms of action, such as photothermal therapy (PTT), and photodynamic therapy (PDT), as well as the drug delivery systems where they display potential benefits towards offering a more targeted treatment approach with fewer side effects. The latest development has shown that they have the prospect of real-time imaging and biomarker identification, and owing to this they are being viewed as a tool for individualized treatment. However, there are still some limitations: challenges of scaling up, biological safety, and bringing it to the clinic. It is therefore incumbent upon these managements to overcome these hurdles to optimize for their impact. As a result, the current findings are briefly reviewed, and the development directions are discussed to support the revolutionary role of Au/Ag nanostructures in cancer research and therapy.

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

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

Thioamides Adjacent to the Ionizable Amine Headgroup in Ionizable Lipids Reduce the pKa of Lipid Nanoparticles and Enhance mRNA Transfection Efficiency in Vitro and in Vivo

Lipid nanoparticles (LNPs) are currently the most clinically advanced mRNA delivery vectors. However, optimizing LNPs for in vivo applications remains largely empirical. The apparent pKa of LNPs is a predictive factor for in vivo performance, with pKa values between 6 and 7 showing the highest efficacy. Despite this critical role of ionizable lipids in LNPs, the relationship between lipid structure and its influence on LNP pKa remains poorly studied. In this study, we report the design and the synthesis of a novel class of ionizable lipids featuring a thioamide moiety, enabling direct comparison between thioamide-containing (SAM) LNPs and amide-containing (OAM) LNPs. We find that substituting oxygen with sulfur in the amide group significantly decreases the apparent pKa of LNPs, increasing the likelihood of identifying lipids in combinatorial libraries that yield LNPs with a pKa in the desired 6-7 range. The reduction in pKa in LNPs containing SAM lipids, compared with OAM lipids, is attributed to the increased hydrophobicity of the thioamide group. Furthermore, by synthesizing multiple libraries of SAM lipids and varying the ionizable head group, alkyl chains, and linker length, we discovered thioamide lipids with distinct tissue tropism, including lipids that mediate splenic targeting by LNPs.

Therapeutic Application of mRNA for Genetic Diseases

While gene therapy has been at the center of an active research field for decades, messenger RNA (mRNA) has long been considered unsuited for therapeutic application due to challenges with stability, immunogenicity, and delivery. Where gene therapy focuses on providing the desired genetic code, mRNA can directly provide the instructions encoded in the corresponding gene. This review aims to explore recent advances in mRNA therapies, building on the success of mRNA COVID-19 vaccines, and extend these insights to the potential treatment of rare genetic diseases. We follow the "outside-in" trajectory of mRNA therapies from administration to intracellular function, focusing on carrier systems such as lipid nanoparticles and virus-like particles, mRNA modifications, and the potential and challenges for clinical applications. To treat rare diseases, different approaches can be envisioned, including chronic or acute delivery of mRNAs encoding functional enzymes for enzyme deficiencies and delivery of CRISPR/Cas9-based gene-editing tools for gene correction. These different approaches determine safety and immunological considerations. By exploring genetic, technical, and therapeutic aspects, this review highlights the potential and current challenges of mRNA therapies to address the large unmet needs in rare genetic disorders.

Emerging Immunotherapies in Lung Cancer: The Latest Advances and the Future of mRNA Vaccines

Lung cancer is the most lethal malignancy worldwide, having the highest incidence rate. This is a heterogeneous disease classified according to its histological and molecular characteristics. Depending on these, different therapeutic approaches have already been approved for lung cancer treatment targeting genetic alterations or even the immune system. Nonetheless, other therapies are being studied to continuously improve the care and survival of lung cancer patients. Among them, immunotherapies are one of the main targets of investigation to try and combat the ability of some malignant cells to evade anti-tumor responses mediated by the immune system. Cancer vaccine development has emerged as a promising approach to strengthen the patient's immune system and combat the disease, especially mRNA vaccines. Currently, there are several ongoing studies investigating the therapeutic efficacy of mRNA vaccines in lung cancer treatment alone or combined with other therapeutic drugs. This review aims to highlight the importance of immunotherapy in lung cancer treatment, presenting the most recent advances particularly in mRNA-based vaccines as well as the challenges and future perspectives.

Ionizable lipid nanoparticles of mRNA vaccines elicit NF-κB and IRF responses through toll-like receptor 4

Ionizable lipid nanoparticles (LNP) that have enabled the success of messenger RNA (mRNA) vaccines have been shown to be immunostimulatory in the absence of mRNA. However, the mechanisms through which they activate innate immune cells is incompletely understood. Using a monocyte cell line, we compared the ability of three LNP formulations to activate transcription factors Nuclear Factor-kappa B (NF-κB) and Interferon Regulatory Factor (IRF). Comparison of signaling in knockout cell lines illustrated a role for Toll-like receptor (TLR) 4 in initiation of this signaling cascade and the contribution of the ionizable lipid component. Activation induced by empty LNPs was similar to that induced by LNPs containing mRNA, indicating that LNPs may provide the majority of innate stimulation for the mRNA vaccine platform. Our findings demonstrate that ionizable lipids within LNPs signal through TLR4 to activate NF-κB and IRF, identifying a mechanism for innate activation that can be optimized for adjuvant design.

Exploring the Challenges of Lipid Nanoparticle Development: The In Vitro-In Vivo Correlation Gap

BACKGROUND/OBJECTIVES

The development of lipid nanoparticles (LNPs) as delivery platforms for nucleic acids has revolutionised possibilities for both therapeutic and vaccine applications. However, emerging studies highlight challenges in achieving reliable in vitro-in vivo correlation (IVIVC), which delays the translation of experimental findings into clinical applications. This study investigates these potential discrepancies by evaluating the physicochemical properties, in vitro efficacy (across three commonly used cell lines), and in vivo performance (mRNA expression and vaccine efficacy) of four LNP formulations.

METHODS

LNPs composed of DSPC, cholesterol, a PEGylated lipid, and one of four ionizable lipids (SM-102, ALC-0315, MC3, or C12-200) were manufactured using microfluidics.

RESULTS

All formulations exhibited comparable physicochemical properties, as expected (size 70-100 nm, low PDI, near-neutral zeta potential, and high mRNA encapsulation). In vitro studies demonstrated variable LNP-mediated mRNA expression in both immortalised and immune cells, with SM-102 inducing significantly higher protein expression (p < 0.05) than the other formulations in immortalised and immune cells. However, in vivo results revealed that ALC-0315 and SM-102-based LNPs achieved significantly (p < 0.05) higher protein expression without a significant difference between them, while MC3- and C12-200-based LNPs exhibited lower expression levels. As vaccine formulations, all LNPs elicited strong immune responses with no significant differences among them.

CONCLUSIONS

These findings highlight the complexities of correlating in vitro and in vivo outcomes in LNP development and demonstrate the importance of holistic evaluation strategies to optimise their clinical translation.

Engineering the physical characteristics of biomaterials for innate immune-mediated cancer immunotherapy

It has recently been recognized that the physical characteristics of biomaterials - such as size, structure, shape, charge, mechanical strength, hydrophobicity, and multivalency - regulate immunological functions in innate immune cells. In immuno-oncology applications, biomaterials are engineered with distinct physical properties to achieve desired innate immune responses. In this review, we discuss how physical characteristics influence effector functions and innate immune signaling pathways in distinct innate immune cell subtypes. We highlight how physical properties of biomaterials impact phagocytosis regulation, biodistribution, and innate immune cell targeting. We outline the recent advances in physical engineering of biomaterials that directly or indirectly induce desired innate immune responses for cancer immunotherapy. Lastly, we discuss the challenges in current biomaterial approaches that need to be addressed to improve clinical applicability.

Inhibiting the Cholesterol Storage Enzyme ACAT1/SOAT1 in Aging Apolipoprotein E4 Mice Alters Their Brains' Inflammatory Profiles

Aging and apolipoprotein E4 (APOE4) are the two most significant risk factors for late-onset Alzheimer's disease (LOAD). Compared to APOE3, APOE4 disrupts cholesterol homeostasis, increases cholesteryl esters (CEs), and exacerbates neuroinflammation in brain cells, including microglia. Targeting CEs and neuroinflammation could be a novel strategy to ameliorate APOE4-dependent phenotypes. Toll-like receptor 4 (TLR4) is a key macromolecule in inflammation, and its regulation is associated with the cholesterol content of lipid rafts in cell membranes. We previously demonstrated that in normal microglia expressing APOE3, inhibiting the cholesterol storage enzyme acyl-CoA:cholesterol acyltransferase 1 (ACAT1/SOAT1) reduces CEs, dampened neuroinflammation via modulating the fate of TLR4. We also showed that treating myelin debris-loaded normal microglia with ACAT inhibitor F12511 reduced cellular CEs and activated ABC transporter 1 (ABCA1) for cholesterol efflux. This study found that treating primary microglia expressing APOE4 with F12511 also reduces CEs, activates ABCA1, and dampens LPS-dependent NFκB activation. In vivo, two-week injections of nanoparticle F12511, which consists of DSPE-PEG2000, phosphatidylcholine, and F12511, to aged female APOE4 mice reduced TLR4 protein content and decreased proinflammatory cytokines, including IL-1β in mice brains. Overall, our work suggests nanoparticle F12511 is a novel agent to ameliorate LOAD.