Department of Laboratory Medicine, University of California San Francisco, San Francisco, California, USA.
Veterans Affairs Medical Center, San Francisco, California, USA.
Microbiol Spectr. 2024 Sep 3;12(9):e0099724. doi: 10.1128/spectrum.00997-24. Epub 2024 Aug 6.
We previously reported that a linear cationic 12-amino acid cell-penetrating peptide (CPP) was bactericidal for . In this study, our objectives were to determine the effect of cyclization of the linear CPP on its antibacterial activity for and cytotoxicity for human cells. We compared the bactericidal effect of 4-hour treatment with the linear CPP to that of CPPs cyclized by a thioether or a disulfide bond on human challenge and multi-drug resistant (MDR) strains of grown in cell culture media with 10% fetal bovine serum (FBS). The effect of lipooligosaccharide (LOS) sialylation on bactericidal activity was analyzed. We determined the ability of the CPPs to treat human cells infected with , to reduce the inflammatory response of human monocytic cells to gonococci, to kill strains of three commensal species, and to inhibit gonococcal biofilms. The cyclized CPPs killed 100% of gonococci from all strains at 100 µM and >90% at 20 µM and were more potent than the linear form. The thioether-linked but not the disulfide-linked CPP was less cytotoxic for human cervical cells compared to the linear CPP. LOS sialylation had minimal effect on bactericidal activity. In treating infected human cells, the thioether-linked CPP at 20 µM killed >60% of extra- and intracellular bacteria and reduced TNF-α expression by THP-1 cells. The potency of the CPPs for the pathogenic and the commensal was similar. The thioether-linked CPP partially eradicated gonococcal biofilms. Future studies will focus on determining efficacy in the female mouse model of gonorrhea.IMPORTANCE remains a major cause of sexually transmitted infections with 82 million cases worldwide in 2020, and 710,151 confirmed cases in the US in 2021, up 25% from 2017. can infect multiple tissues including the urethra, cervix, rectum, pharynx, and conjunctiva. The most serious sequelae are suffered by infected women as gonococci ascend to the upper reproductive tract and cause pelvic inflammatory disease, chronic pelvic pain, and infertility in 10%-20% of women. Control of gonococcal infection is widely recognized as increasingly challenging due to the lack of any vaccine. has quickly developed resistance to all but one class of antibiotics and the emergence of multidrug-resistant strains could result in untreatable infections. As such, gonorrhea is classified by the Center for Disease Control (CDC) as an urgent public health threat. The research presented herein on new therapeutics for gonorrhea has identified a cyclic cell-penetrating peptide (CPP) as a potent molecule targeting .
我们之前报道过一种线性阳离子 12 个氨基酸的细胞穿透肽（CPP）对淋病奈瑟菌具有杀菌作用。在这项研究中，我们的目的是确定线性 CPP 环化对其杀菌活性的影响，以及对人细胞的细胞毒性。我们比较了 4 小时治疗线性 CPP 与通过硫醚或二硫键环化的 CPP 对细胞培养物中含 10%胎牛血清（FBS）的人挑战和多药耐药（MDR）淋病奈瑟菌菌株的杀菌作用。分析了脂寡糖（LOS）唾液酸化对杀菌活性的影响。我们测定了 CPP 治疗感染淋病奈瑟菌的人细胞、减少人单核细胞对淋球菌的炎症反应、杀死三种共生淋病奈瑟菌种菌株以及抑制淋球菌生物膜的能力。在 100µM 时，所有菌株的环化 CPP 均能杀死 100%的淋球菌，在 20µM 时>90%，比线性形式更有效。与线性 CPP 相比，硫醚键合但不是二硫键合的 CPP 对人宫颈细胞的细胞毒性更小。LOS 唾液酸化对杀菌活性的影响最小。在治疗感染的人细胞时，20µM 的硫醚键合 CPP 杀死了超过 60%的胞外和胞内细菌，并降低了 THP-1 细胞中 TNF-α 的表达。CPP 对致病性和共生淋病奈瑟菌的效力相似。硫醚键合 CPP 部分消除了淋球菌生物膜。未来的研究将集中在确定女性小鼠淋病模型中的疗效。
重要性
淋病奈瑟菌仍然是全球 2020 年 8200 万性传播感染病例和美国 2021 年 710151 例确诊病例的主要原因，比 2017 年增加了 25%。淋病奈瑟菌可感染尿道、宫颈、直肠、咽和结膜等多种组织。最严重的后遗症是感染女性的后果，因为淋球菌向上生殖道上升并导致盆腔炎、慢性盆腔痛和 10%-20%女性不孕。由于缺乏任何疫苗，控制淋病奈瑟菌感染被广泛认为越来越具有挑战性。淋病奈瑟菌已迅速对除一类抗生素以外的所有抗生素产生耐药性，多药耐药菌株的出现可能导致无法治疗的感染。因此，疾病控制与预防中心（CDC）将淋病列为紧急公共卫生威胁。本文关于淋病新疗法的研究确定了一种环状细胞穿透肽（CPP）作为一种针对淋病奈瑟菌的有效分子。
