Multidrug-resistant Pseudomonas aeruginosa (PA) causes severe infections, with severe burden especially in older adults. Vaccines remain effective and are urgently needed despite immunosenescence. Self-assembling nanoparticles can enhance vaccine immunogenicity, but their translational use is constrained by the useless anticarrier immunity and carrier-induced epitope suppression (CIES). Herein, we developed a protective-antigen-based nanoparticle platform in which the PA chaperonin GroEL, an intrinsically self-assembling protective antigen, serves as the scaffold for a fusion immunogen reGroEL-PO, which displays the PcrV-OprI antigen (rePO). In mice, pre-existing anti-GroEL immunity did not blunt responses but enhanced anti-rePO immunity. Mechanistically, reGroEL-PO increased antigen uptake by antigen-presenting cells, promoted dendritic-cell maturation and accelerated both humoral and cellular immunity. In addition, reGroEL-PO elicited immune responses and conferred protection in adult and aged mice. These data demonstrate reGroEL-PO as a PA vaccine candidate and illustrate a nanoparticle design that leverages protective carriers and circumvents CIES effects.
The escalating crisis of multidrug-resistant bacteria necessitates innovative antibiotic discovery platforms. Conventional antimicrobial peptide (AMP) mining often relies on complete biosynthetic gene clusters (BGCs), leaving fragmented genomic resources underexplored. Here, we present an evolution-inspired approach to reconstruct and predict AMPs from partial BGCs. Applying this strategy to 954 Paenibacillus genomes identifies five polymyxin-like peptides, NP001-NP005, with broad in vitro activity. Crucially, in murine models of polymyxin-resistant infection, NP001 reduced bacterial burdens by up to 1,000-fold in a thigh infection model and improved survival (50% vs. 0%) in a lethal peritonitis model. Structural simulations and biophysical assays revealed that NP001 maintains high affinity for bacterial membranes and effectively binds to MCR-1-modified lipid A, a key colistin-resistance mechanism. Moreover, Leu at position 10 of NP001 plays a key role in antibacterial activity against MCR-1-resistant bacteria. Our work establishes a generalizable framework for AMP discovery and introduces a promising therapeutic candidate, NP001, which effectively counteracts polymyxin-resistant pathogens.
