The design and synthesis of enhanced membrane-intercalating biomaterials for drug delivery or vascular membrane targeting is currently challenged by the lack of screening and prediction tools. The present work demonstrates the generation of a Quantitative Structural Activity Relationship model (QSAR) to make a priori predictions. Amphiphilic macromolecules (AMs) "stealth lipids" built on aldaric and uronic acids frameworks attached to poly(ethylene glycol) (PEG) polymer tails were developed to form self-assembling micelles. In the present study, a defined set of novel AM structures were investigated in terms of their binding to lipid membrane bilayers using Quartz Crystal Microbalance with Dissipation (QCM-D) experiments coupled with computational coarse-grained molecular dynamics (CG MD) and all-atom MD (AA MD) simulations. The CG MD simulations capture the insertion dynamics of the AM lipophilic backbones into the lipid bilayer with the PEGylated tail directed into bulk water. QCM-D measurements with Voigt viscoelastic model analysis enabled the quantitation of the mass gain and rate of interaction between the AM and the lipid bilayer surface. Thus, this study yielded insights about variations in the functional activity of AM materials with minute compositional or stereochemical differences based on membrane binding, which has translational potential for transplanting these materials in vivo. More broadly, it demonstrates an integrated computational-experimental approach, which can offer a promising strategy for the in silico design and screening of therapeutic candidate materials.

The accumulated evidence has shown that lipids and polymers each have distinct advantages as carriers for siRNA delivery. Composite materials comprising both lipids and polymers may present improved properties that combine the advantage of each. Cationic amphiphilic macromolecules (CAMs) containing a hydrophobic alkylated mucic acid segment and a hydrophilic poly(ethylene glycol) (PEG) tail were non-covalently complexed with two lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), to serve as a siRNA delivery vehicle. By varying the weight ratio of CAM to lipid, cationic complexes with varying compositions were obtained in aqueous media and their properties evaluated. CAM-lipid complex sizes were relatively independent of composition, ranging from 100 to 200nm, and zeta potentials varied from 10 to 30mV. Transmission electron microscopy confirmed the spherical morphology of the complexes. The optimal N/P ratio was 50 as determined by electrophoretic mobility shift assay. The ability to achieve gene silencing was evaluated by anti-luciferase siRNA delivery to a U87-luciferase cell line. Several weight ratios of CAM-lipid complexes were found to have similar delivery efficiency compared to the gold standard, Lipofectamine. Isothermal titration calorimetry revealed that siRNA binds more tightly at pH=7.4 than pH=5 to CAM-lipid (1:10 w/w). Further intracellular trafficking studies monitored the siRNA escape from the endosomes at 24h following transfection of cells. The findings in the paper indicate that CAM-lipid complexes can serve as a novel and efficient siRNA delivery vehicle.

Although viral hepatocellular carcinoma (HCC) is declining, nonviral HCC, which often is the end stage of nonalcoholic or alcoholic steatohepatitis (NASH, ASH), is on an upward trajectory. Immune checkpoint inhibitors (ICIs) that block the T cell inhibitory receptor PD-1 were approved for treatment of all HCC types. However, only a minority of HCC patients show a robust and sustained response to PD-1 blockade, calling for improved understanding of factors that negatively impact response rate and duration and the discovery of new adjuvant treatments that enhance ICI responsiveness. Using a mouse model of NASH-driven HCC, we identified peritumoral fibrosis as a potential obstacle to T cell-mediated tumor regression and postulated that antifibrotic medications may increase ICI responsiveness. We now show that the angiotensin II receptor inhibitor losartan, a commonly prescribed and safe antihypertensive drug, reduced liver and peritumoral fibrosis and substantially enhanced anti-PD-1-induced tumor regression. Although losartan did not potentiate T cell reinvigoration, it substantially enhanced HCC infiltration by effector CD8⁺ T cells compared to PD-1 blockade alone. The beneficial effects of losartan correlated with blunted TGF-β receptor signaling, reduced collagen deposition, and depletion of immunosuppressive fibroblasts.

Insulin inhibits gluconeogenesis and stimulates glucose conversion to glycogen and lipids. How these activities are coordinated to prevent hypoglycemia and hepatosteatosis is unclear. Fructose-1,6-bisphosphatase (FBP1) is rate controlling for gluconeogenesis. However, inborn human FBP1 deficiency does not cause hypoglycemia unless accompanied by fasting or starvation, which also trigger paradoxical hepatomegaly, hepatosteatosis, and hyperlipidemia. Hepatocyte FBP1-ablated mice exhibit identical fasting-conditional pathologies along with AKT hyperactivation, whose inhibition reversed hepatomegaly, hepatosteatosis, and hyperlipidemia but not hypoglycemia. Surprisingly, fasting-mediated AKT hyperactivation is insulin dependent. Independently of its catalytic activity, FBP1 prevents insulin hyperresponsiveness by forming a stable complex with AKT, PP2A-C, and aldolase B (ALDOB), which specifically accelerates AKT dephosphorylation. Enhanced by fasting and weakened by elevated insulin, FBP1:PP2A-C:ALDOB:AKT complex formation, which is disrupted by human FBP1 deficiency mutations or a C-terminal FBP1 truncation, prevents insulin-triggered liver pathologies and maintains lipid and glucose homeostasis. Conversely, an FBP1-derived complex disrupting peptide reverses diet-induced insulin resistance.