Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide

Abstract

Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. To address this significant problem, a cleavable conjugate of the antibiotic kanamycin and a non-membrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophage more potently than a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

Host defense antimicrobial peptides as antibiotics: design and application strategies

“…In another interesting experiment, kanamycin plus a cell penetration peptide (P14LRR) can release the antibiotic in a reduced cellular environment, leading to effective clearing intracellular pathogens ( Mycobacterium tuberculosis ) within macrophages. It is also effective in vivo against Salmonella in a Caenorhabditis elegans model [47*]. …”

Brucella Melitensis 16M Regulates the Effect of AIR Domain on Inflammatory Factors, Autophagy, and Apoptosis in Mouse Macrophage through the ROS Signaling Pathway

“…The anti-apoptotic protein Bcl-2 can inhibit ROS-induced lipid peroxidation by suppressing ROS production[24]. Studies have confirmed that Brucella infection can cause autophagy, inflammation, and apoptosis[25]; however, whether it is through the AIR domain or the ROS pathway has not been reported. Therefore, this study systematically explored whether the inflammation, autophagy, and apoptosis caused by Brucella infection is associated with the AIR domain and ROS pathway.…”

Drug delivery systems designed to overcome antimicrobial resistance

“…Meanwhile, the conjugate ( 90 ) protected by carboxybenzyl group (Cbz) (Figure ), was designed to measure the release of the kanamycin component from the disulfide‐containing conjugate by HPLC. These were of 1.5 ± 0.2 and 4 hours for half‐life and full release, respectively . The authors also showed that the ester bond of ( 87 ) was not susceptible to esterase enzymatic activity, probably due to steric hindrance of kanamycin around this ester bond (Figure ).…”

“…Like Mycobacterium, Salmonella , and Brucella are intracellular bacteria that reside inside mammalian host cells (eg, macrophages), where they reproduce and form a long‐term colonization, thus causing chronic and difficult‐to‐treat infections . Brezden et al recently reported interesting conjugates (Figure ), consisting of the aminoglycoside antibiotic kanamycin ( 85 ) with the CPP P14LRR ( 86 ), which when conjugated exhibited potent ATB activity against these intracellular pathogens . The CPP ( 86 ) previously demonstrated intrinsic ATB activity against intracellular Salmonella and Brucella bacteria .…”

“…In Brezden et al's study, kanamycin ( 85 ) was linked to ( 86 ), with or without a cleavable disulfide linkage, to form the conjugates ( 87 ) and ( 88 ) (Figure ). This attachment increased the overall net positive charge of the conjugates (from +8 to +12), therefore, facilitating the penetration and accumulation of the drug into J774A.1 host cells . The disulfide‐containing conjugate ( 87 ) was broken down, under reducing conditions, in the intracellular environment of the host cell, into free kanamycin ( 85 ) and the thiol‐modified P14SH peptide ( 89 ) (Figure ), which then exerted its ATB actions.…”