Instituto de Biología Molecular y Celular de Rosario Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Bioquímicas y Farmacéuticas, Departamento de Microbiología, Universidad Nacional de Rosario, Rosario S2000EZP, Argentina.
Farmacognosia, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rosario 2000, Argentina.
J Antimicrob Chemother. 2024 Aug 1;79(8):1820-1830. doi: 10.1093/jac/dkae151.
The upsurge of antimicrobial resistance demands innovative strategies to fight bacterial infections. With traditional antibiotics becoming less effective, anti-virulence agents or pathoblockers, arise as an alternative approach that seeks to disarm pathogens without affecting their viability, thereby reducing selective pressure for the emergence of resistance mechanisms.
To elucidate the mechanism of action of compound N'-(thiophen-2-ylmethylene)benzohydrazide (A16B1), a potent synthetic hydrazone inhibitor against the Salmonella PhoP/PhoQ system, essential for virulence.
The measurement of the activity of PhoP/PhoQ-dependent and -independent reporter genes was used to evaluate the specificity of A16B1 to the PhoP regulon. Autokinase activity assays with either the native or truncated versions of PhoQ were used to dissect the A16B1 mechanism of action. The effect of A16B1 on Salmonella intramacrophage replication was assessed using the gentamicin protection assay. The checkerboard assay approach was used to analyse potentiation effects of colistin with the hydrazone. The Galleria mellonella infection model was chosen to evaluate A16B1 as an in vivo therapy against Salmonella.
A16B1 repressed the Salmonella PhoP/PhoQ system activity, specifically targeting PhoQ within the second transmembrane region. A16B1 demonstrates synergy with the antimicrobial peptide colistin, reduces the intramacrophage proliferation of Salmonella without being cytotoxic and enhances the survival of G. mellonella larvae systemically infected with Salmonella.
A16B1 selectively inhibits the activity of the Salmonella PhoP/PhoQ system through a novel inhibitory mechanism, representing a promising synthetic hydrazone compound with the potential to function as a Salmonella pathoblocker. This offers innovative prospects for combating Salmonella infections while mitigating the risk of antimicrobial resistance emergence.
抗菌药物耐药性的不断上升，要求我们采取创新策略来对抗细菌感染。随着传统抗生素的效果逐渐减弱，抗毒剂或病原体失活剂作为一种替代方法应运而生，它旨在削弱病原体的毒性而不影响其生存能力，从而降低耐药机制出现的选择性压力。
阐明 N'-(噻吩-2-亚甲基)苯甲酰肼（A16B1）化合物的作用机制，该化合物是一种针对沙门氏菌 PhoP/PhoQ 系统的强效合成腙抑制剂，该系统对毒力至关重要。
通过测量 PhoP/PhoQ 依赖性和非依赖性报告基因的活性，评估 A16B1 对 PhoP 调控子的特异性。使用天然或截断的 PhoQ 进行自激酶活性测定，以剖析 A16B1 的作用机制。使用庆大霉素保护试验评估 A16B1 对沙门氏菌在巨噬细胞内复制的影响。采用棋盘试验方法分析该腙与多粘菌素的增效作用。选择大蜡螟感染模型来评估 A16B1 作为治疗沙门氏菌感染的体内疗法。
A16B1 抑制了沙门氏菌 PhoP/PhoQ 系统的活性，特异性靶向 PhoQ 位于第二跨膜区域内。A16B1 与抗菌肽多粘菌素表现出协同作用，减少了沙门氏菌在巨噬细胞内的增殖，且无细胞毒性，并提高了全身性感染沙门氏菌的大蜡螟幼虫的存活率。
A16B1 通过一种新颖的抑制机制选择性抑制沙门氏菌 PhoP/PhoQ 系统的活性，代表了一种有前途的合成腙化合物，具有作为沙门氏菌病原体失活剂的潜力。这为对抗沙门氏菌感染提供了创新性的前景，同时降低了抗菌药物耐药性出现的风险。
