Molecular Pharmaceutics

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality worldwide. This clinical burden is predominantly attributable to atherothrombotic events resulting from platelet hyperactivation, a process integral to the pathophysiology of atherosclerosis. Cilostazol (CLZ) is a clinically established phosphodiesterase-IIIA inhibitor with antiplatelet and vasodilatory activity. However, its extremely low aqueous solubility results in dissolution-limited and variable oral absorption, while dose-dependent adverse effects and cardiovascular safety restrictions may constrain its clinical use. Lipid-polymer hybrid nanoparticles (LPHNPs) represent a highly promising drug delivery system to address these biopharmaceutical limitations. However, their interactions with blood components remain poorly understood, with surface charge among the most controversial physicochemical parameters implicated in platelet toxicity. Here, we applied an integrated ex vivo and in silico screening strategy to design LPHNPs based on poly(lactic acid) and poly(ethylene glycol)-modified lipids displaying positive (amine), nominally neutral (methoxy), and negative (carboxyl) surface charges to systematically identify safe boundaries at the nano-human platelet interface and evaluate their suitability as CLZ carriers. Positively charged nanoparticles precipitated immediately during self-assembly due to uncontrolled ionic pairing and were therefore structurally unviable. Neutral nanoparticles maintained a stable size (~113 nm hydrodynamic diameter) but unexpectedly induced spontaneous platelet aggregation, limiting their applicability. In contrast, negatively charged nanoparticles exhibited exceptional colloidal stability (hydrodynamic size of ~120 nm and zeta potential of -48 mV), achieved significant inhibition of ADP-induced platelet aggregation, and adhered to the platelet surface without inducing activation or membrane disruption. Steered molecular dynamics simulations, performed under identical non-equilibrium pulling conditions, showed the highest interfacial resistance to CLZ extraction for the negatively charged model, qualitatively consistent with the sustained CLZ release profile observed in vitro. These findings highlight the importance of precise surface charge tuning in the development of safe cardiovascular nanomedicines based on LPHNPs, emphasizing the need for comprehensive platelet compatibility testing before further biological evaluation.

Previously, we demonstrated the biosafety of polyethylene glycol-coated iron oxide nanoparticles (MAG@PEG) in a cellular model of viral oncogenesis, supporting their further preclinical evaluation. Herein, we evaluated the safety and biodistribution of MAG@PEG in tumor-bearing mice and assessed the influence of an external magnetic field on nanoparticle distribution. Animals were randomly assigned to three groups: G1, control (PBS); G2, MAG@PEG (10 mg/kg); and G3, MAG@PEG (10 mg/kg) with magnetic exposure for 1 h. Doses were administered intraperitoneally weekly for 1 month. Results showed that animal behavior and body weight were unaffected by MAG@PEG, while tumor growth was significantly reduced only in G2. Biodistribution studies based on tissue magnetization revealed higher magnetic iron levels in the stomach followed by the spleen, lungs, and tumors, particularly in G2. Histological analysis detected Prussian blue-positive staining mainly in the spleen and in lymphoid-associated structures in the lung, stomach and intestine, while a fraction of MAG@PEG remained within the peritoneal cavity. Serum biochemistry showed no evidence of nephrotoxicity. Furthermore, hemocompatibility studies using human blood samples demonstrated that MAG@PEG was non-hemolytic according to the ASTM F756 standard. Taken together, the biodistribution, histological, biochemical, and hemocompatibility findings provide a comprehensive preclinical assessment of the biosafety of MAG@PEG and identify the route of administration and magnetic targeting as key determinants of nanoparticle biodistribution.

This study evaluated the Delayed Cmax Drug Delivery System (DCMax), an erosion-based controlled- release formulation designed to delay peak plasma concentration (Cmax) and sustain drug release. The tablet matrix contained hydroxypropyl methylcellulose, hydroxypropyl methylcellulose acetate succinate, and polyethylene oxide. In-vitro dissolution and erosion studies confirmed the delayed release profile. In-vivo performance was assessed in six healthy volunteers by measuring salivary caffeine concentrations after administration of immediate-release caffeine tablets and DCMax tablets. DCMax induced a delayed Cmax of 5 hours compared with 1 hour for the immediate-release formulation, while peak concentrations were lower compared to immediate release. These findings demonstrate that erosion-based drug delivery can achieve delayed release, with potential application in chronotherapy for endocrine disorders.

Our prior works have demonstrated the therapeutic potential extracellular vesicles (EVs) derived from batch cultures of brain endothelial cells (BECs) owing to their ability to transfer mitochondria to injured recipient cells. However, conventional batch/flask cultures limit scalable and reproducible production of EVs. Here, we evaluated a CELLine AD1000 bioreactor as a platform for sustained production of EVs from mouse b.End3 BECs and compared bioreactor-derived (BR) EVs with EVs obtained conventional batch cultures (BT). Large EVs (lEVs) and small (sEVs) were isolated using a sequential centrifugation protocol and were characterized using dynamic light scattering, nanoparticle tracking analysis, microBCA assay, western blotting, proteomics analysis, and their ability to rescue bioenergetics in oxygen-glucose deprived (OGD) BECs. Bioreactor cultures maintained high cell viabilities (~90%) for up to eight weeks and produced approximately three- to four-fold greater EV protein yields than batch cultures. BR EVs showed reproducible particle characteristics consistent with EV subtypes derived from BT cultures. CD63, CD9 and Arf6 were detected in EV fractions, whereas the mitochondrial outer-membrane protein TOMM20 was enriched in lEVs. Proteomic analyses revealed that bioreactor-derived lEVs retained the mitochondrial cargo signature observed in batch-derived lEVs. Both bioreactor and batch EVs restored relative ATP levels in ODG-exposed BECs. These findings suggest that bioreactor BEC cultures are a scalable approach for generating functionally active BEC-EVs for downstream characterization and therapeutic development.

In pre-clinal studies, VC108, a novel GPR39 inhibitor, increased myocardial O2 tension (mpO2) during different phases of acute myocardial infarction (AMI). The purpose of this work was to investigate the temporal effects of VC108 on mpO2 using a novel population PK/PD model developed from preclinical data using healthy animals and animals subjected to AMI protocols. PK/PD simulations were then performed to explore mpO2 dynamic in untested experimental scenarios. VC108 PK data fitted well to a two-compartment model with linear elimination with body weight, sex, and nominal dose identified as significant covariates influencing clearance and/or central compartment volume. Applying indirect effect model principles for representing mpO2 flux, a structural population PK/PD model was developed to capture mpO2 dynamics during different AMI phases: before and during coronary occlusion and after reperfusion. The model successfully captured basal mpO2 homeostasis, ischemic decline, and reperfusion overshoot, while quantifying the contribution of VC108 to collateral blood flow and functional recovery. Dose response relationships were simulated to measure the effect of different VC108 dose levels on permanent damage, i.e. a reduction in mpO2 at steady state after AMI. The probability of remaining below predefined damage thresholds (mpO2 reduction of 5% to 20%) increased with dose in both sexes, with females consistently achieving greater protection that plateaued around 1 mg/kg of VC108 for higher permanent damage. This model represents a valuable tool to describe, for the first time, VC108 efficacy data and pharmacokinetics with ischemia/reperfusion dynamics and quantify its effect in untested dose levels.

Cationic lipid nanoparticles have demonstrated unique potential for extrahepatic mRNA delivery, particularly enabling selective targeting of the pulmonary endothelium. However, their translational development has been hampered by reports of infusion-related immune reactions and innate immune system activation, most notably transient complement activation. Here, we present a case study illustrating the discovery and translational advancement of a selected cationic LNP into non-human primates (NHPs) for initial pharmacokinetic assessment and evaluation of potential immunostimulatory side effects. We show surface charge dependent organ-selective expression of reporter mRNAs from different LNPs in vivo. An mRNA encoding the Tie2 agonist COMP-Angl, was formulated with LNP002, and respective pharmacokinetic and pharmacodynamic readouts were analyzed in two independent non-human primate studies. Notably, dose-dependent transient complement activation could be abrogated by extending the infusion time. Finally, we identified the blood-borne pharmacodynamic biomarker PDGFB for LNP002/mRNA-76 treatment reflecting activated Tie2-signalling in healthy pulmonary endothelium in vivo supported by single cell sequencing and cluster-alignment of downstream effector genes with the same spatial profile as the delivered mRNA.

Stereotactic needle-based delivery remains the standard for local administration of Advanced Therapy Medicinal Products (ATMPs) to the human brain. ATMP administration typically involves multiple trajectories, presenting cumulative risks and prolonging surgery. Reflux-prone, patchy therapy coverage compromises clinical results. We demonstrate a novel approach, deploying a helical delivery catheter via a single access trajectory per target, referred to as SpiraMed. Helix retraction is synchronised with therapy delivery, enabling comprehensive target coverage in seconds. Helix pitch and diameter can be precisely tailored to patient-specific target volume and vascular anatomy, as part of the preoperative stereotactic surgical planning process. Testing in agarose phantoms, live sheep and cadaveric human brain confirms enhanced therapy delivery volume, delivery speed and target coverage, with reductions in reflux and predicted risk of bleeding complication. SpiraMed represents a new paradigm, promising to help deliver on the transformative potential of cell and gene therapies across the spectrum of human CNS disease.

Nanoparticle albumin-bound paclitaxel (Abraxane) was among the first clinically approved nanomedicines and is a first-line chemotherapeutic. It enhances therapeutic efficacy and reduces side effects of paclitaxel. Despite its extensive clinical use, mechanisms of Abraxane's therapeutic effects are the subject of ongoing study. This work posits a new mechanism for Abraxane's effects in lung cancers and metastasis. Tracing the albumin component of Abraxane with radioisotopes or fluorophores, we find that Abraxane homes to the lungs. Abraxane's lung tropism is elevated by inflammation and is eliminated in complement protein C3 knockout mice, showing that complement pathway drives the uptake. Flow cytometry and histology show that neutrophils are the dominant cell type taking up Abraxane in the lungs. We demonstrate Abraxane's tropism to pulmonary neutrophils in mice and in human donor lungs. We note previously undocumented side effects associated with Abraxane's lung tropism, including pro-thrombotic and pro-inflammatory responses in acute lung inflammation. We show that Abraxane's efficacy against lung metastases is affected when lung uptake is eliminated by C3 knockout. Our results provide insight into why Abraxane is effective in lung cancer and metastases. These findings may be used to improve outcomes in patients receiving Abraxane and help design next-generation cancer nanomedicines.

TROP2-targeted antibody-drug conjugates (ADCs) have demonstrated promising clinical activity in triple-negative breast cancer (TNBC) as monotherapies; however, therapeutic benefit varies among patients. Combination strategies pairing TROP2-targeted ADCs with immune checkpoint inhibitors are also being investigated. Elucidating the mechanistic drivers of ADC monotherapy variability and enabling the rational development of combination regimens require computational frameworks that integrate ADC pharmacology with tumor-immune interactions. A quantitative systems pharmacology (QSP) model is presented that incorporates an ADC module into our established immuno-oncology model for TNBC. The module captures ADC and payload pharmacokinetics and pharmacodynamics. TNBC heterogeneity is represented by two tumor cell clones with high and low TROP2 expression, informed by prior characterizations, and differential sensitivity to the ADC payload is incorporated as an intrinsic property of each clone. Although generalizable, the model was applied to the TROP2-targeted ADC sacituzumab govitecan (SG, TRODELVY). A virtual patient cohort was generated using Latin hypercube sampling and calibrated against objective response rate (ORR) data from SG Phase I/II TNBC basket trial. The model predicted an ORR of 33.2% consistent with ASCENT study (NCT02574455). Simulations suggest TROP2-mediated delivery contributes modestly to SG efficacy with tumor exposure driven largely by systemically released SN-38 payload being sufficient to induce cytotoxicity. Tumor heterogeneity emerged as a key determinant of response with ORR increasing as the fraction of payload-sensitive clones increased. Overall, this QSP framework for TROP2-targeted ADCs accounts for TNBC heterogeneity and is extendable to other ADCs and targets enabling interrogation of ADC mechanisms of action in conjunction with tumor-immune interactions.

Despite intensive treatment, high-risk neuroblastoma (HRNB) remains a leading cause of cancer-related mortality in children. Current treatment paradigms include multimodal systemic treatments and multi-agent chemotherapy, which is limited by substantial acute and long-term toxicities. Platinum-based chemotherapy is a cornerstone of this treatment but is fraught with side effects and stands to benefit from dose reduction strategies. MicroRNA (miR)-based therapeutics represent an attractive strategy to simultaneously moderate multiple oncogenic pathways, providing a potential avenue to enhance the efficacy of current treatment regimens. However, the development of miR therapeutics has largely relied on chemically synthesized ones, which are limited by issues of inconsistency and poor in vivo stability. Biologically produced, tRNA/pre-miR containing bioengineered miRs (bioRNAs) address these limitations. We investigated the therapeutic potential of bioRNA encoding miR-124 and miR-34a across molecularly distinct HRNB models and evaluated their ability to enhance cisplatin efficacy. Both bioRNAs significantly suppressed neuroblastoma cell viability in vitro, with proteomic analyses demonstrating preferential induction of neuronal differentiation by miR-124 and apoptotic signaling by miR-34a. Combining bioRNA with cisplatin produced robust synergy across multiple HRNB lines, enhancing apoptosis while simultaneously promoting differentiation-associated phenotypes. In vivo, both bioRNAs suppressed tumor growth as monotherapies, while combination with low-dose cisplatin produced the strongest responses across multiple xenograft models with different HRNB subtypes. Notably, low-dose cisplatin combined with bioRNA therapy frequently achieved tumor control comparable to, or greater than, that observed with high-dose cisplatin monotherapy while maintaining favorable tolerability. These findings establish bioRNAs as potent cisplatin sensitizers and support bioRNA-based combination therapy as a strategy for improving HRNB treatment while reducing chemotherapy-associated toxicity in children.

Glial cells play essential roles in maintaining neural tissue homeostasis and limiting the spread of injury-induced neuroinflammation, yet their dysfunction can also exacerbate neurodegenerative, neuroimmune, and neurodevelopmental disorders. Therapeutic targeting of specific glial cell populations would open up new treatment possibilities, but currently available viral and non-viral delivery vehicles are limited by carrier toxicity as well as poor delivery efficiency and specificity. To work towards new glia-targeted, non-viral delivery vehicles, we performed an in silico analysis on neural cell specific RNA-Seq datasets in mice to identify surface molecules differentially enriched on neurons, astrocytes, and microglia. We identified Slc2a5 (Glut5) as a microglia-enriched transporter and validated its microglia specific expression in healthy murine neural tissue using RNA in situ hybridization. By employing a sequential thiol-ene and enzymatic catalyzed reaction scheme, we synthesized polyelectrolytic dendrimers with multivalent presentation of fructose, the natural ligand for Glut5, and formulated nano-sized polyionic complexes (PICs) loaded with protein or nucleic acid cargo by mixing oppositely charged dendrimers. Fructose functionalized PICs lacking cationic surface charge enabled fructose-dependent intracellular protein delivery to Glut5-expressing human breast cancer cells (MCF-7) and mouse fibroblasts, while restricting uptake by Glut5-negative mouse astrocytes, confirming transporter-dependent selectivity in vitro. Fructose functionalized PICs resulted in minimal neuroinflammation when injected into mouse striatum at 1 mg/ml but elicited concentration-dependent neural tissue toxicity at higher doses. Fructose-PICs failed to achieve microglia specific intracellular delivery of functional proteins when injected into healthy neural tissue but aided in directing protein delivery to microglia and astrocytes at ischemic stroke lesions. Together, our findings demonstrate proof-of-principle for using in silico RNA-seq screening workflows to identify cell specific surfaceome targets and incorporating that insight into a modular biomaterial platform for targeted drug delivery.

Background: More than 90% of rare diseases lack an approved therapy, partly reflecting economic barriers in developing treatments for small patient populations. A common bottleneck is costly and resource-intensive hit-to-lead prioritization. Congenital contractures of the limbs and face, hypotonia, and developmental delay (CLIFAHDD) is an ultra-rare neurodevelopmental disease often caused by de novo gain-of-function variants in the sodium leak channel NALCN, with no approved treatments. Methods: We developed a cost and resource-efficient, AI-enabled translational drug discovery framework integrating phenotypic high-throughput screening (HTS), structural biology foundation models for hit-to-lead prioritization, and orthogonal experimental validation. We applied this framework for drug repurposing to identify NALCN inhibitors as therapeutic candidates for CLIFAHDD. We screened ~1,200 approved drugs using a fluorescence-based membrane potential assay in doxycycline-inducible HEK293 cells stably expressing the NALCN channelosome. Boltz-2 modeling predicted binding affinity and mode to prioritize hits. Lead repurposing candidates were selected by a multidisciplinary expert review panel. Lead candidates were evaluated using patch-clamp electrophysiology in HEK293 cells expressing wild-type or CLIFAHDD-associated NALCN variants, primary mouse hippocampal neurons, and a C. elegans NALCN gain-of-function model. Results: HTS identified 11 candidate NALCN inhibitors. Boltz-2 prioritized candidates based on predicted binding affinity and predicted binding within the NALCN pore, consistent with a direct pore-blocking mechanism. Aprepitant emerged as the lead candidate after multidisciplinary evaluation based on its predicted mechanism, pharmacologic properties, blood-brain barrier penetration, established safety profile, and regulatory approval in children and adults. Patch-clamp electrophysiology confirmed partial inhibition of NALCN-mediated sodium leak currents in HEK293 cells (IC50;=2.22 M), with comparable potency against Cav3.1 (IC50=1.63 M). In primary mouse hippocampal neurons, aprepitant reduced sodium leak currents, hyperpolarized resting membrane potential, and decreased spontaneous firing. Aprepitant rescued hyperlocomotor and dystonic phenotypes in a C. elegans gain-of-function NALCN model. There was notable concordance between AI-predicted hits, phenotypic screening hits, and experimental validation. Conclusion: These findings identify aprepitant as a lead therapeutic candidate for CLIFAHDD, and establish an AI-enabled translational drug discovery framework integrating phenotypic screening, structural modeling, and experimental validation for NALCN channelopathies. This scalable and resource-conscious strategy may accelerate hit-to-lead prioritization and drug discovery for rare and ultra-rare diseases lacking effective therapies.

The delivery of small-molecule therapeutics across cellular membranes remains a fundamental challenge in drug development, particularly for compounds whose physicochemical properties limit intracellular bioavailability. Inspired by the low toxicity, biodegradability, and synthetic accessibility of triethanolamine-derived lipids, we investigated a series of C18 aminotriester lipids as excipients for the codelivery of anticancer therapeutics. Four structurally related triester lipids bearing saturated, cis-monounsaturated, trans-monounsaturated, and di-unsaturated C18 tails were synthesized through straightforward esterification reactions with triethanolamine. These lipids were evaluated for their ability to enhance the antiproliferative activity of several anticancer agents, including paclitaxel, doxorubicin, amonafide, homoharringtonine, camptothecin, and SN-38. Across multiple drug classes, the aminotriester lipids exhibited minimal intrinsic cytotoxicity and generally produced limited enhancement of drug potency. However, the fully saturated tris-stearate aminotriester lipid selectively enhanced the antiproliferative activity of amonafide in HCT-116 colorectal cancer cells, particularly at lower concentrations. In contrast, unsaturated lipid analogues displayed negligible enhancement effects, and the activity of the tris-stearate lipid was substantially attenuated in A549 lung adenocarcinoma cells, weakly observed in HT-29 colorectal cancer cells, and absent in CT26 murine colorectal cancer cells. Lactate dehydrogenase release assays indicated that these effects were not associated with membrane lysis or nonspecific cytotoxicity. Further, fluorescence microscopy time course experiments suggest improved membrane trafficking of amonafide when codelivered stoichiometrically with fully saturated C18 aminotriester lipids. Collectively, these findings demonstrate that saturated triethanolamine-based aminotriester lipids may function as selective and biocompatible codelivery excipients for certain small-molecule therapeutics. The observed dependence on both lipid saturation state and cellular context suggests that membrane organization and lipid packing may play important roles in mediating these effects. These results establish a foundation for further mechanistic investigations into aminotriester lipid-assisted small-molecule delivery systems.

Immunotoxins (ITs) are potent targeted cancer therapeutics that couple tumor-selective receptor binding with efficient intracellular delivery and cytotoxic enzymatic activity of bacterial toxins. While ITs have shown impressive efficacy in hematologic malignancies, dose-limiting toxicity remains a major barrier to their broader clinical application, particularly in solid tumors. The exceptional potency of immunotoxin payloads contributes to off-tumor toxicity because even limited uptake by receptor-low cells can be sufficient to cause cell death. Here, we systematically investigated how receptor-binding domain (RBD) affinity and avidity interact with catalytic payload activity to determine IT selectivity. Using CD123-, HER3-, and HER2-targeted ITs, we found that increasing receptor-binding affinity or avidity altered potency but provided limited control over the selectivity between receptor-high and receptor-low cells. In contrast, attenuating catalytic activity produced profound gains in selectivity when payload potency was appropriately matched to receptor engagement. The optimal level of attenuation varied with receptor context and toxin scaffold, demonstrating that maximal selectivity emerges from balancing cellular delivery with catalytic activity rather than maximizing either property alone. In vivo, payload attenuation increased the maximum tolerated dose of a HER2-targeted IT by 400-fold and enabled robust antitumor activity well below its toxicity limit, whereas the WT counterpart showed no detectable efficacy at tolerated doses. Together, these findings uncover and establish payload activity as a tunable determinant of immunotoxin selectivity and provide a framework for matching receptor engagement with catalytic potency to develop safer and more broadly applicable targeted toxins.

Influenza A virus (IAV) defective interfering particles (DIPs) are regarded as promising broad-spectrum antivirals due to their high efficacy demonstrated in animal trials. Previously, an OP7 chimera DIP was generated that showed markedly enhanced antiviral efficacy compared to conventional IAV DIPs. In addition, a high-yield cell culture-based production process for OP7 chimera DIPs was established in perfusion mode. However, due to the technical complexity of this technology, we aimed to combine the advantages of perfusion in terms of yield with that of a simple and less complex batch process. In the present work, we established a fed-batch production process for OP7 chimera DIPs that allows a more straightforward implementation into existing production facilities. Using a feeding regime that was able to overcome the cell density effect, we achieved productive virus infection in stirred tank reactors until a cell density of 10E+6 cells/mL. Furthermore, we obtained a high virus titer of 3.8 log10(HAU/100 uL), corresponding to a 3.4-fold increase compared to a reference batch production. Moreover, the produced material demonstrated a significantly increased interfering bioactivity shown by an in vitro potency assay. Interestingly, this efficacy was similarly high as compared to OP7 chimera DIP material previously produced in perfusion mode, despite twofold lower virus titers. Finally, we demonstrate robustness of OP7 chimera DIP seed virus trains, which is significant step towards later pharmaceutical production. Further, corresponding GMP MDCK-PB2(sus) cell and OP7 chimera virus banks are now available for later biomanufacturing further use. In conclusion, the established fed-batch process offers a valid n additional option for pharmaceutical grade OP7 chimera DIP GMP manufacturing production under GMP conditions required for subsequent clinical testing and for later large-scale manufacturing.

Lipid nanoparticles (LNPs) are a leading drug delivery platform for mRNA or other nucleic acid-based therapeutics. LNP platforms are typically composed of ionizable aminolipids, phospholipids, sterols, and lipids tagged with polyethylene glycol. The ionizable aminolipids are typically cationic at low pH, allowing them to encapsulate negatively charged mRNA. The pH at which the ionizable head groups change charge states, the apparent pKa, is crucial to understand the characteristics and formulation of LNP. However, this is difficult to measure as the apparent pKa differs from the pKa of the aminolipids in bulk solution due to the complex chemical and charge environment. In this study, we use molecular dynamics (MD) simulations with alchemical free energy perturbation to calculate the pKa shift as a function of lipid composition, treating LNP-like and vesicle-like environments. Our results show that the pH-dependent structure of the systems affects the trends in pKa shifts in complex ways, driven by factors including surface electrostatics and lipid internalization. Our all-atom simulation protocol allows us to efficiently estimate the apparent pKa of LNP-like models formed with novel ionizable aminolipids and estimate how it will change with composition.

Biological systems such as extracellular vesicles (EVs) are highly sophisticated and functionally diverse. Despite growing recognition of EVs' roles in health and disease through mediating intercellular communication, their inherent heterogeneity and challenges in purity and yield hinder their mechanistic research and clinical translation. To address this gap, we sought to translate essential EV properties into a controllable and simplified platform by engineering biomimetic synthetic vesicles (SVs) incorporating defined proteins and lipids. Using microfluidics, we generated SVs loaded with bulk membrane and cytosolic proteins from cancer cells, as well as individual organotropism-associated integrins. Bulk membrane protein incorporation into SVs reduced surface charge, modified lipid profiles, and enhanced cellular uptake, while integrin incorporation altered biodistribution. To investigate protein loading, we profiled input materials and SVs by mass spectrometry, identifying features linked to high incorporation, such as low molecular weight, positive charge, high isoelectric point, and predicted stability, globularity, lipidation, and amphipathic helices. This work presents a synthetic platform for dissecting the roles of EV-associated features and cargo, while providing insights into protein properties relevant to the optimization of delivery systems.

BackgroundSevere community-acquired pneumonia (CAP) remains a leading cause of mortality in children under five. The PediCAP trial evaluated oral step-down therapy using dispersible amoxicillin or amoxicillin/clavulanate tablets in African children hospitalised with severe CAP. Dispersible tablet formulations are preferred in children; however, pharmacokinetic data for oral amoxicillin/clavulanate in paediatric populations remain limited. We characterised the pharmacokinetics of 4:1, 7:1, and 14:1 dispersible amoxicillin/clavulanate tablets in children enrolled in the PediCAP trial and predicted target attainment under different dosing schemes. MethodsChildren were randomised within 24 hours of starting intravenous antibiotics to oral step-down therapy with weight-banded dosing of twice-daily amoxicillin/clavulanate (4:1, 7:1, or 14:1). Plasma concentrations were quantified following intensive sampling and analysed using nonlinear mixed-effects modelling with allometric scaling and postmenstrual age-dependent clearance maturation. Pharmacodynamic indices included %fT>MIC for amoxicillin and %fT>Ct for clavulanate. ResultsA total of 157 children (median [range] age, 12 [2-70] months; weight, 8.4 [4.0-22.0] kg) contributed 707 paired concentrations. Amoxicillin was described by a two-compartment model and clavulanate by a one-compartment model, both with sequential zero-and first-order absorption. Typical clearance for an 8-kg individual at full maturation was 11.8L/h for amoxicillin and 6.1L/h for clavulanate. Pharmacokinetics were similar between the formulation ratios. Weight-banded dosing achieved balanced exposures across weight groups. Amoxicillin achieved 40%fT>MIC for MICs[≤]2mg/L. A proposed clavulanate target of 20%fT>0.5mg/L was achieved in most children even at the lowest amoxicillin/clavulanate ratio. ConclusionWeight-banded dosing using dispersible amoxicillin/clavulanate tablets provide consistent exposure profiles in African children with severe CAP. SUMMARYPopulation pharmacokinetic modelling of dispersible amoxicillin/clavulanate tablets (4:1, 7:1, 14:1) in 157 African children with severe pneumonia showed weight-banded dosing achieved consistent and adequate amoxicillin and clavulanate exposures across formulations.

Protein replacement therapy is highly effective for treating many protein-deficiency disorders, but its long-term clinical benefit is often limited by anti-drug antibody responses that neutralize therapeutic proteins, compromising safety and efficacy. To address these unwanted immune responses, a lipid nanoparticle-based immunotherapy platform has been developed to induce antigen-specific tolerance. Mice treated with antigen associated with either double-chain phosphatidylserine (PS) or lysophosphatidylserine (LysoPS), a single-acyl-chain phospholipid, showed reduced antibody titers following subcutaneous pre-exposure. However, only LysoPS nanoparticles induced tolerance after oral administration, suggesting structural differences between PS and LysoPS can impact tolerogenic potential, depending on the site of delivery. As an apoptotic "eat-me" signal, PS is recognized by phagocytic receptors such as TIM-4 and is associated with LC3-associated phagocytosis. These nanoparticles have been hypothesized to promote apoptotic mimicry to regulate immunity. However, the contribution of TIM-4 to oral tolerance remains unclear. Here, we investigated the role of TIM-4 in LysoPS-mediated oral tolerance using a knockout mouse model. Our data showed that TIM-4-/- mice induced tolerance to ovalbumin encapsulated in LysoPS comparable to that of wild-type mice. We also found that LysoPS nanoparticles did not follow the same surface engagement and intracellular trafficking pathways as PS nanoparticles. These results reveal that, despite sharing the same headgroup, differences in acyl chain number critically shape nanoparticle-immune cell interactions and provide a mechanistic framework that may explain the unique ability of LysoPS nanoparticles to induce oral tolerance.

Albumin binding can substantially alter the unbound concentration and apparent cellular potency of small-molecule anticancer agents. BAY-1816032 is a selective BUB1 kinase inhibitor with activity in malignant pleural mesothelioma, but its interaction with serum albumin has not been defined. This study combined intrinsic bovine serum albumin (BSA) fluorescence measurements, molecular docking, and cell-viability assays to examine whether albumin association influences BAY-1816032 activity. BAY-1816032 produced pronounced quenching of BSA fluorescence at low drug-to-protein molar ratios, and the quenching response was greater at mildly acidic pH than at mildly basic pH. Docking to BSA (PDB 4F5S) placed the top-ranked pose in Sudlow site I (subdomain IIA), with a Vina score of -7.8 kcal/mol and predicted hydrogen-bond contacts with Tyr149, Arg256, and Asp450. In NCI-H28, NCI-H2052, NCI-H2452, and AB12 mesothelioma cells, supplementation of 10% fetal bovine serum medium with 2% (w/v; 20 mg/mL) BSA shifted BAY-1816032 concentration-response curves to the right. Relative to 10% serum alone, IC50 values increased from 2.4 to 11.1 uM in H28, 3.6 to 22.0 uM in H2052, 2.0 to 4.9 uM in H2452, and 2.4 to 11.1 uM in AB12. These data support an albumin-dependent reduction in the freely available drug fraction and identify site I as the leading computational binding-site hypothesis. Because fluorescence-intensity and docking data do not independently establish a dissociation constant or quenching mechanism, direct unbound-fraction measurements and competitive displacement experiments are required for quantitative confirmation.