Precision treatment of viral pneumonia through macrophage-targeted lipid nanoparticle delivery.

Macrophages are integral components of the innate immune system, playing a dual role in host defense during infection and pathophysiological states. Macrophages contribute to immune responses and aid in combatting various infections, yet their production of abundant proinflammatory cytokines can lead to uncontrolled inflammation and worsened tissue damage. Therefore, reducing macrophage-derived proinflammatory cytokine release represents a promising approach for treating various acute and chronic inflammatory disorders. However, limited macrophage-specific delivery vehicles have hindered the development of macrophage-targeted therapies. In this study, we screened a pool of 112 lipid nanoparticles (LNPs) to identify an optimal LNP formulation for efficient siRNA delivery. Subsequently, by conjugating the macrophage-specific antibody F4/80 to the LNP surface, we constructed MacLNP, an enhanced LNP formulation designed for targeted macrophage delivery. In both in vitro and in vivo experiments, MacLNP demonstrated a significant enhancement in targeting macrophages. Specifically, delivery of siRNA targeting TAK1, a critical kinase upstream of multiple inflammatory pathways, effectively suppressed the phosphorylation/activation of NF-kB. LNP-mediated inhibition of NF-kB, a key upstream regulator in the classic inflammatory signaling pathway, in the murine macrophage cell line RAW264.7 significantly reduced the release of proinflammatory cytokines after stimulation with the viral RNA mimic Poly(I:C). Finally, intranasal administration of MacLNP-encapsulated TAK1 siRNA markedly ameliorated lung injury induced by influenza infection. In conclusion, our findings validate the potential of targeted macrophage interventions in attenuating inflammatory responses, reinforcing the potential of LNP-mediated macrophage targeting to treat pulmonary inflammatory disorders.

Ionizable Lipid Nanoparticles for In Vivo mRNA Delivery to the Placenta during Pregnancy.

Ionizable lipid nanoparticles (LNPs) are the most clinically advanced nonviral platform for mRNA delivery. While they have been explored for applications including vaccines and gene editing, LNPs have not been investigated for placental insufficiency during pregnancy. Placental insufficiency is caused by inadequate blood flow in the placenta, which results in increased maternal blood pressure and restricted fetal growth. Therefore, improving vasodilation in the placenta can benefit both maternal and fetal health. Here, we engineered ionizable LNPs for mRNA delivery to the placenta with applications in mediating placental vasodilation. We designed a library of ionizable lipids to formulate LNPs for mRNA delivery to placental cells and identified a lead LNP that enables in vivo mRNA delivery to trophoblasts, endothelial cells, and immune cells in the placenta. Delivery of this top LNP formulation encapsulated with VEGF-A mRNA engendered placental vasodilation, demonstrating the potential of mRNA LNPs for protein replacement therapy during pregnancy to treat placental disorders.

Rational Design of Nanomedicine for Placental Disorders: Birthing a New Era in Women's Reproductive Health.

The placenta is a transient organ that forms during pregnancy and acts as a biological barrier, mediating exchange between maternal and fetal circulation. Placental disorders, such as preeclampsia, fetal growth restriction, placenta accreta spectrum, and gestational trophoblastic disease, originate in dysfunctional placental development during pregnancy and can lead to severe complications for both the mother and fetus. Unfortunately, treatment options for these disorders are severely lacking. Challenges in designing therapeutics for use during pregnancy involve selectively delivering payloads to the placenta while protecting the fetus from potential toxic side effects. Nanomedicine holds great promise in overcoming these barriers; the versatile and modular nature of nanocarriers, including prolonged circulation times, intracellular delivery, and organ-specific targeting, can control how therapeutics interact with the placenta. In this review, nanomedicine strategies are discussed to treat and diagnose placental disorders with an emphasis on understanding the unique pathophysiology behind each of these diseases. Finally, prior study of the pathophysiologic mechanisms underlying these placental disorders has revealed novel disease targets. These targets are highlighted here to motivate the rational design of precision nanocarriers to improve therapeutic options for placental disorders.

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

During healthy pregnancy, the placenta develops to allow for exchange of nutrients and oxygen between the mother and the fetus. However, placental dysregulation can lead to several pregnancy disorders, such as preeclampsia and fetal growth restriction. Recently, lipid nanoparticle (LNP)-mediated delivery of messenger RNA (mRNA) has been explored as a promising approach to treat these disorders. Here, iterative libraries of LNPs with varied excipient molar ratios are screened in vitro for enhanced mRNA delivery to placental cells with minimal cytotoxicity when compared to an LNP formulation with a standard excipient molar ratio. LNP C5, the top formulation identified by these screens, demonstrates a fourfold increase in mRNA delivery in vitro compared to the standard formulation. Intravenous administration of LNP C5 to pregnant mice achieves improved in vivo placental mRNA delivery compared to the standard formulation and mediates mRNA delivery to placental trophoblasts, endothelial cells, and immune cells. These results identify LNP C5 as a promising optimized LNP formulation for placental mRNA delivery and further validates the design of experiments strategy for LNP excipient optimization to enhance mRNA delivery to cell types and organs of interest.

EGFR-targeted ionizable lipid nanoparticles enhance in vivo mRNA delivery to the placenta.

The full potential of ionizable lipid nanoparticles (LNPs) as an in vivo nucleic acid delivery platform has not yet been realized given that LNPs primarily accumulate in the liver following systemic administration, limiting their success to liver-centric conditions. The engineering of LNPs with antibody targeting moieties can enable extrahepatic tropism by facilitating site-specific LNP tethering and driving preferential LNP uptake into receptor-expressing cell types via receptor-mediated endocytosis. Obstetric conditions stemming from placental dysfunction, such as preeclampsia, are characterized by overexpression of cellular receptors, including the epidermal growth factor receptor (EGFR), making targeted LNP platforms an exciting potential treatment strategy for placental dysfunction during pregnancy. Herein, an EGFR antibody-conjugated LNP (aEGFR-LNP) platform was developed by engineering LNPs with increasing densities of antibody functionalization. aEGFR-LNPs were screened in vitro in immortalized placental trophoblasts and in vivo in non-pregnant and pregnant mice and compared to non-targeted formulations for extrahepatic, antibody-targeted mRNA LNP delivery to the placenta. Our top performing LNP with an intermediate density of antibody functionalization (1:5 aEGFR-LNP) mediated a âˆ¼twofold increase in mRNA delivery in murine placentas and a âˆ¼twofold increase in LNP uptake in EGFR-expressing trophoblasts compared to non-targeted counterparts. These results demonstrate the potential of antibody-conjugated LNPs for achieving extrahepatic tropism, and the ability of aEGFR-LNPs in promoting mRNA delivery to EGFR-expressing cell types in the placenta.