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Kong D, Hua X, Zhou R, Cui J, Wang T, Kong F, You H, Liu X, Adu-Amankwaah J, Guo G, Zheng K, Wu J, Tang R. Antimicrobial and Anti-Inflammatory Activities of MAF-1-Derived Antimicrobial Peptide Mt6 and Its D-Enantiomer D-Mt6 against Acinetobacter baumannii by Targeting Cell Membranes and Lipopolysaccharide Interaction. Microbiol Spectr 2022; 10:e0131222. [PMID: 36190276 PMCID: PMC9603722 DOI: 10.1128/spectrum.01312-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 08/30/2022] [Indexed: 12/30/2022] Open
Abstract
Antibiotic resistance in Acinetobacter baumannii is on the rise around the world, highlighting the urgent need for novel antimicrobial drugs. Antimicrobial peptides (AMPs) contribute to effective protection against infections by pathogens, making them the most promising options for next-generation antibiotics. Here, we report two designed, cationic, antimicrobial-derived peptides: Mt6, and its dextroisomer D-Mt6, belonging to the analogs of MAF-1, which is isolated from the instar larvae of houseflies. Both Mt6 and D-Mt6 have a broad-spectrum antimicrobial activity that is accompanied by strong antibacterial activities, especially against A. baumannii planktonic bacteria and biofilms. Additionally, the effect of D-Mt6 against A. baumannii is stable in a variety of physiological settings, including enzyme, salt ion, and hydrogen ion environments. Importantly, D-Mt6 cleans the bacteria on Caenorhabditis elegans without causing apparent toxicity and exhibits good activity in vivo. Both Mt6 and D-Mt6 demonstrated synergistic or additive capabilities with traditional antibiotics against A. baumannii, demonstrating their characteristics as potential complements to combination therapy. Scanning electron microscopy (SEM) and laser scanning confocal microscope (LSCM) experiments revealed that two analogs displayed rapid bactericidal activity by destroying cell membrane integrity. Furthermore, in lipopolysaccharide (LPS)-stimulated macrophage cells, these AMPs drastically decreased IL-1β and TNF-a gene expression and protein secretion, implying anti-inflammatory characteristics. This trait is likely due to its dual function of directly binding LPS and inhibiting the LPS-activated mitogen-activated protein kinase (MAPK) signaling pathways in macrophages. Our findings suggested that D-Mt6 could be further developed as a novel antimicrobial/anti-inflammatory agent and used in the treatment of A. baumannii infections. IMPORTANCE Around 700,000 people worldwide die each year from antibiotic-resistant pathogens. Acinetobacter baumannii in clinical specimens increases year by year, and it is developing a strong resistance to clinical drugs, which is resulting in A. baumannii becoming the main opportunistic pathogen. Antimicrobial peptides show great potential as new antibacterial drugs that can replace traditional antibiotics. In our study, Mt6 and D-Mt6, two new antimicrobial peptides, were designed based on a natural peptide that we first discovered in the hemlymphocytes of housefly larvae. Both Mt6 and D-Mt6 showed broad-spectrum antimicrobial activity, especially against A. baumannii, by damaging membrane integrity. Moreover, D-Mt6 showed better immunoregulatory activity against LPS induced inflammation through its LPS-neutralizing and suppression on MAPK signaling. This study suggested that D-Mt6 is a promising candidate drug as a derived peptide against A. baumannii.
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Affiliation(s)
- Delong Kong
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Xuan Hua
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Rui Zhou
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Jie Cui
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
| | - Tao Wang
- School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
- Key Laboratory of Medical Microbiology and Parasitology of Education Department of Guizhou, Guizhou Medical University, Guiyang, Guizhou, China
| | - Fanyun Kong
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Hongjuan You
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | - Xiangye Liu
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
| | | | - Guo Guo
- School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
| | - Kuiyang Zheng
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
- National Demonstration Center for Experimental Basic Medical Sciences Education, Xuzhou Medical University, Xuzhou, China
| | - Jianwei Wu
- School of Basic Medical Sciences, Guizhou Medical University, Guiyang, China
| | - Renxian Tang
- Jiangsu Key Laboratory of Immunity and Metabolism, Department of Pathogenic Biology and Immunology, Xuzhou Medical University, Xuzhou, China
- National Demonstration Center for Experimental Basic Medical Sciences Education, Xuzhou Medical University, Xuzhou, China
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