Nanoformulated Single-Stranded RNA-Based Adjuvant with a Coordinative Amphiphile as an Effective Stabilizer: Inducing Humoral Immune Response by Activation of Antigen-Presenting Cells.

As agonists of TLR7/8, single-stranded RNAs (ssRNAs) are safe and promising adjuvants that do not cause off-target effects or innate immune overactivation. However, low stability prevents them from mounting sufficient immune responses. This study evaluates the adjuvant effects of ssRNA derived from the cricket paralysis virus intergenic region internal ribosome entry site, formulated as nanoparticles with a coordinative amphiphile, containing a zinc/dipicolylamine complex moiety as a coordinative phosphate binder, as a stabilizer for RNA-based adjuvants. The nanoformulated ssRNA adjuvant was resistant to enzymatic degradation in vitro and in vivo, and that with a coordinative amphiphile bearing an oleyl group (CA-O) was approximately 100 nm, promoted effective recognition, and improved activation of antigen-presenting cells, leading to better induction of neutralizing antibodies following single immunization. Hence, CA-O may increase the efficacy of ssRNA-based adjuvants, proving useful to meet the urgent need for vaccines during pathogen outbreaks.

Development of benzimidazole-based derivatives as antimicrobial agents and their synergistic effect with colistin against gram-negative bacteria.

Gram-negative bacteria pose a distinctive risk worldwide, especially with the evolution of major resistance to carbapenems, fluoroquinolones and colistin. Therefore, development of new antibacterial agents to target Gram-negative infections is of utmost importance. Using phenotypic screening, we synthesized and tested thirty-one benzimidazole derivatives against E. coli JW55031 (TolC mutant strain). Compound 6c showed potent activity with MIC value of 2 µg/ml, however, it lacked activity against several Gram-negative microbes with intact efflux systems, including E. coli BW25113 (wild-type strain). Combination of 6c with colistin partially restored its antibacterial activity against wild strains (MIC range, 8-16 µg/ml against E. coli, K. pneumoniae, A. baumannii, and P. aeruginosa). 6c exhibited no cytotoxicity against two mammalian cell lines. Therefore, compound 6c represents a promising lead for further optimization to overcome Gram-negative resistance alone or in combination therapy.