摘要

       CXCL14是一个具有抗菌活性的CXC趋化因子家族，在C末端含有一个双亲阳离子α螺旋区，这是抗菌肽（AMPs）的一个特征性结构。本研究设计了三种CXCL1459-75（CXCL14-C17）类似物，对应于CXCL14的C端α-螺旋结构，对多种革兰氏阴性和阳性细菌具有潜在的抗菌活性，最低抑菌浓度为4-16μM，无哺乳动物细胞毒性。此外，通过在CXCL14-C17中引入Lys、Arg或Trp，设计了两种具有改进的细胞选择性的CXCL14-C17类似物（CXCL14-C17-a1和CXCL14-C17-a3）。此外，CXCL14-C17类似物与氯霉素和环丙沙星对耐多药铜绿假单胞菌（MDRPA）的协同作用（FICI:0.3125-0.375）明显强于LL-37（FICI:0.75-1.125）。CXCL14-C17类似物对耐甲氧西林金黄色葡萄球菌（MRSA）、MDRPA和耐万古霉素粪肠球菌（VREF）等耐药菌的抗菌活性高于LL-37和蜂毒素。特别是CXCL14-C17-a2和CXCL14-C17-a3在亚MIC时完全抑制了生物膜的形成，所有的肽都能消除预先形成的生物膜。膜去极化、流式细胞术、sytox-green摄取、ONPG水解和共聚焦显微镜显示天然肽（CXCL14-C17）可能是细胞内的靶点，而双亲设计的类似物则以细菌膜为靶点。CXCL14-C17也表现出与buforin-2相似的DNA结合特性。有趣的是，CXCL14-C17-a2和CXCL14-C17-a3有效地抑制了脂多糖（LPS）刺激的RAW264.7细胞产生和表达一氧化氮（NO）、肿瘤坏死因子（TNF）-α、白细胞介素（IL）-6和单核细胞趋化蛋白（MCP）-1，提示这些肽可能是很有前途的抗炎和抗菌药物。

       CXCL14 is a CXC chemokine family that exhibits antimicrobial activity and contains an amphipathic cationic α-helical region in the C-terminus, a characteristic structure of antimicrobial peptides (AMPs). In this study, we designed three analogs of CXCL14_59-75 (named CXCL14-C17) corresponding to the C-terminal α-helix of CXCL14, which displayed potential antimicrobial activity against a wide variety of gram-negative and gram-positive bacteria with minimum inhibitory concentrations of 4-16 μM without mammalian cell toxicity. Furthermore, two CXCL14-C17 analogs (CXCL14-C17-a1 and CXCL14-C17-a3) with improved cell selectivity were engineered by introducing Lys, Arg, or Trp in CXCL14-C17. Additionally, CXCL14-C17 analogs showed much greater synergistic effect (FICI: 0.3125-0.375) with chloramphenicol and ciprofloxacin against multidrug-resistant Pseudomonas aeruginosa (MDRPA) than LL-37 did (FICI: 0.75-1.125). CXCL14-C17 analogs were more active against antibiotic-resistant bacteria including methicillin-resistant Staphylococcus aureus (MRSA), MDRPA, and vancomycin-resistant Enterococcus faecium (VREF) than LL-37 and melittin. In particular, CXCL14-C17-a2 and CXCL14-C17-a3 completely inhibited the biofilm formation at sub-MIC and all of the peptides were able to eliminate pre-formed biofilm as well. Membrane depolarization, flow cytometry, sytox green uptake, ONPG hydrolysis and confocal microscopy revealed the possible target of the native peptide (CXCL14-C17) to likely be intracellular, and the amphipathic designed analogs targeted the bacterial membrane. CXCL14-C17 also showed DNA binding characteristic activity similar to buforin-2. Interestingly, CXCL14-C17-a2 and CXCL14-C17-a3 effectively inhibited the production and expression of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-6, and monocyte chemoattractant protein (MCP)-1 from lipopolysaccharide (LPS)-stimulated RAW264.7 cells, suggesting that these peptides could be promising anti-inflammatory and antimicrobial agents.

        https://www.sciencedirect.com/science/article/pii/S0005273618301925?via%3Dihub