School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, 210009, PR China.
School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, 210009, PR China.
Microb Pathog. 2020 Jan;138:103847. doi: 10.1016/j.micpath.2019.103847. Epub 2019 Nov 5.
Helicobacter pylori (H. pylori) infection is highly prevalent, and has developed antimicrobial resistance to virtually all existing antibiotics. Currently, treatment of H. pylori infection (involving proton pump inhibitors and broad-spectrum antibiotics) is suboptimal, with high failure rates. Thus, there is a pressing need to develop new anti-H. pylori therapies. Cbf-K, a cathelicidin-like antimicrobial peptide, presented broad antimicrobial activity during our previous research. This study further evaluated the therapeutic potential and the mode of action underlying Cbf-K against clarithromycin- and amoxicillin-resistant H. pylori SS1. The MIC and MBC of Cbf-K against the tested H. pylori were 16 and 32 μg/ml, respectively, and its killing kinetics was time-dependent, reflecting the thorough elimination of drug-resistant bacteria within 24 h. This peptide also protected H. pylori-infected gastric epithelial cells (GES-1) from death by reducing the cell supernatant and intracellular bacterial counts by 1.9 and 2.9-log units, respectively. These data indicated the powerful antimicrobial effects of Cbf-Kin vitro. Meanwhile, notable antimicrobial activity in the mouse gastritis model was observed, with decreasing bacterial counts by 3.9-log units in stomach tissues and Cbf-K could effectively suppress the secretion of inflammatory cytokine IL-8. For its mode of action, Cbf-K not only neutralized the negative potential and increased the membrane uptake of NPN and PI by 78.5% and 85.1%, respectively, but also bound to genomic DNA, which in turn downregulated the expression of adhesion genes (alpA and alpB) and virulence gene (cagA), indicating its effective activities on membrane disruption, DNA-binding and gene expression. The data above demonstrated that Cbf-K possessed effective antimicrobial and anti-inflammatory activities and downregulated the expression of adhesion- and cytotoxin-associated genes of drug-resistant H. pylori SS1, making it a potential candidate for anti-infective therapy.
幽门螺杆菌（H. pylori）感染极为普遍，且几乎对所有现有的抗生素都产生了抗药性。目前，H. pylori 感染的治疗（涉及质子泵抑制剂和广谱抗生素）并不理想，失败率很高。因此，迫切需要开发新的抗 H. pylori 疗法。我们之前的研究表明，一种抗菌肽 Cbf-K 具有广泛的抗菌活性。本研究进一步评估了 Cbf-K 对克拉霉素和阿莫西林耐药的 H. pylori SS1 的治疗潜力和作用机制。Cbf-K 对测试的 H. pylori 的 MIC 和 MBC 分别为 16 和 32μg/ml，其杀菌动力学呈时间依赖性，反映了在 24 小时内彻底消除耐药菌。该肽还通过将细胞上清液和细胞内细菌计数分别减少 1.9 和 2.9 个对数单位，从而保护 H. pylori 感染的胃上皮细胞（GES-1）免受死亡。这些数据表明 Cbf-K 在体外具有强大的抗菌作用。同时，在小鼠胃炎模型中观察到显著的抗菌活性，胃组织中的细菌计数减少了 3.9 个对数单位，Cbf-K 可以有效抑制炎症细胞因子 IL-8 的分泌。关于其作用机制，Cbf-K 不仅中和了负电位，并分别将 NPN 和 PI 的膜摄取增加了 78.5%和 85.1%，而且与基因组 DNA 结合，从而下调了粘附基因（alpA 和 alpB）和毒力基因（cagA）的表达，表明其在膜破坏、DNA 结合和基因表达方面具有有效的活性。上述数据表明，Cbf-K 具有有效的抗菌和抗炎活性，并下调了耐药 H. pylori SS1 的粘附和细胞毒素相关基因的表达，使其成为抗感染治疗的潜在候选药物。
