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Troiano C, De Ninno A, Casciaro B, Riccitelli F, Park Y, Businaro L, Massoud R, Mangoni ML, Bisegna P, Stella L, Caselli F. Rapid Assessment of Susceptibility of Bacteria and Erythrocytes to Antimicrobial Peptides by Single-Cell Impedance Cytometry. ACS Sens 2023. [PMID: 37421371 PMCID: PMC10391704 DOI: 10.1021/acssensors.3c00256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2023]
Abstract
Antimicrobial peptides (AMPs) represent a promising class of compounds to fight antibiotic-resistant infections. In most cases, they kill bacteria by making their membrane permeable and therefore exhibit low propensity to induce bacterial resistance. In addition, they are often selective, killing bacteria at concentrations lower than those at which they are toxic to the host. However, clinical applications of AMPs are hindered by a limited understanding of their interactions with bacteria and human cells. Standard susceptibility testing methods are based on the analysis of the growth of a bacterial population and therefore require several hours. Moreover, different assays are required to assess the toxicity to host cells. In this work, we propose the use of microfluidic impedance cytometry to explore the action of AMPs on both bacteria and host cells in a rapid manner and with single-cell resolution. Impedance measurements are particularly well-suited to detect the effects of AMPs on bacteria, due to the fact that the mechanism of action involves perturbation of the permeability of cell membranes. We show that the electrical signatures of Bacillus megaterium cells and human red blood cells (RBCs) reflect the action of a representative antimicrobial peptide, DNS-PMAP23. In particular, the impedance phase at high frequency (e.g., 11 or 20 MHz) is a reliable label-free metric for monitoring DNS-PMAP23 bactericidal activity and toxicity to RBCs. The impedance-based characterization is validated by comparison with standard antibacterial activity assays and absorbance-based hemolytic activity assays. Furthermore, we demonstrate the applicability of the technique to a mixed sample of B. megaterium cells and RBCs, which paves the way to study AMP selectivity for bacterial versus eukaryotic cells in the presence of both cell types.
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Affiliation(s)
- Cassandra Troiano
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Adele De Ninno
- Institute for Photonics and Nanotechnologies, Italian National Research Council, 00133 Rome, Italy
| | - Bruno Casciaro
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, 00185 Rome, Italy
| | - Francesco Riccitelli
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Yoonkyung Park
- Department of Biomedical Science, College of Natural science, Chosun University, Gwangju 61452, Republic of Korea
| | - Luca Businaro
- Institute for Photonics and Nanotechnologies, Italian National Research Council, 00133 Rome, Italy
| | - Renato Massoud
- Department of Experimental Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Maria Luisa Mangoni
- Laboratory affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, 00185 Rome, Italy
| | - Paolo Bisegna
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Lorenzo Stella
- Department of Chemical Science and Technologies, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Federica Caselli
- Department of Civil Engineering and Computer Science, University of Rome Tor Vergata, 00133 Rome, Italy
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Gu H, Kato T, Kumeta H, Kumaki Y, Tsukamoto T, Kikukawa T, Demura M, Ishida H, Vogel HJ, Aizawa T. Three-Dimensional Structure of the Antimicrobial Peptide Cecropin P1 in Dodecylphosphocholine Micelles and the Role of the C-Terminal Residues. ACS OMEGA 2022; 7:31924-31934. [PMID: 36120057 PMCID: PMC9475619 DOI: 10.1021/acsomega.2c02778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/23/2022] [Indexed: 05/31/2023]
Abstract
Cecropin P1 (CP1) isolated from a large roundworm Ascaris suum, which is found in pig intestines, has been extensively studied as a model antimicrobial peptide (AMP). However, despite being a model AMP, its antibacterial mechanism is not well understood, particularly the function of its C-terminus. By using an Escherichia coli overexpression system with calmodulin as a fusion partner, we succeeded in the mass expression of recombinant peptides, avoiding toxicity to the host and degradation of CP1. The structure of the recombinant 15N- and 13C-labeled CP1 and its C-terminus truncated analogue in dodecylphosphocholine (DPC) micelles was determined by NMR. In this membrane-mimetic environment, CP1 formed an α-helix for almost its entire length, except for a short region at the C-terminus, and there was no evidence of a hinge, which is considered important for the expression of activity in other cecropins. Several NMR analyses showed that the entire length of CP1 was protected from water by micelles. Since the loss of the C-terminus of the analogue had little effect on the NMR structure or its interaction with the micelle, we investigated another role of the C-terminus of CP1 in its antimicrobial activity. The results showed that the C-terminal region affected the DNA-binding capacity of CP1, and this mechanism of action was also newly suggested that it contributed to the antimicrobial activity of CP1.
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Affiliation(s)
- Hao Gu
- Graduate
School of Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Takasumi Kato
- Graduate
School of Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Hiroyuki Kumeta
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Yasuhiro Kumaki
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Takashi Tsukamoto
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Takashi Kikukawa
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Makoto Demura
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
| | - Hiroaki Ishida
- Department
of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Hans J. Vogel
- Department
of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Tomoyasu Aizawa
- Faculty
of Advanced Life Science, Hokkaido University, N10, W8, Kita-ku, Sapporo 060-0810, Japan
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