ABSTRACT
The delivery of oligonucleotides across biological barriers is a challenge of unsurpassed significance at the interface of materials science and medicine, with emerging clinical utility in prophylactic and therapeutic vaccinations, immunotherapies, genome editing, and cell rejuvenation. Here, we address the role of readily available branched lipids in the design, synthesis, and evaluation of isoprenoid charge-altering releasable transporters (CARTs), a pH-responsive oligomeric nanoparticle delivery system for RNA. Systematic variation of the lipid block reveals an emergent relationship between the lipid block and the neutralization kinetics of the polycationic block. Unexpectedly, iA21A11, a CART with the smallest lipid side chain, isoamyl-, was identified as the lead isoprenoid CART for the in vitro transfection of immortalized lymphoblastic cell lines. When administered intramuscularly in a murine model, iA21A11-mRNA complexes induce higher protein expression levels than our previous lead CART, ONA. Isoprenoid CARTs represent a new delivery platform for RNA vaccines and other polyanion-based therapeutics.
ABSTRACT
The global challenge of antibiotic resistance necessitates the introduction of more effective antibiotics. Here we report a potentially general design strategy, exemplified with vancomycin, that improves and expands antibiotic performance. Vancomycin is one of the most important antibiotics in use today for the treatment of Gram-positive infections. However, it fails to eradicate difficult-to-treat biofilm populations. Vancomycin is also ineffective in killing Gram-negative bacteria due to its inability to breach the outer membrane. Inspired by our seminal studies on cell penetrating guanidinium-rich transporters (e.g., octaarginine), we recently introduced vancomycin conjugates that effectively eradicate Gram-positive biofilm bacteria, persister cells and vancomycin-resistant enterococci (with V-r8, vancomycin-octaarginine), and Gram-negative pathogens (with V-R, vancomycin-arginine). Having shown previously that the spatial array (linear versus dendrimeric) of multiple guanidinium groups affects cell permeation, we report here for the first time vancomycin conjugates with dendrimerically displayed guanidinium groups that exhibit superior efficacy and breadth, presenting the best activity of V-r8 and V-R in single broad-spectrum compounds active against ESKAPE pathogens. Mode-of-action studies reveal cell-surface activity and enhanced vancomycin-like killing. The vancomycin-polyguanidino dendrimer conjugates exhibit no acute mammalian cell toxicity or hemolytic activity. Our study introduces a new class of broad-spectrum vancomycin derivatives and a general strategy to improve or expand antibiotic performance through combined mode-of-action and function-oriented design studies.
