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Kowal MD, Seifried TM, Brouwer CC, Tavakolizadeh H, Olsén E, Grant E. Electrophoretic Deposition Interferometric Scattering Mass Photometry. ACS NANO 2024; 18:10388-10396. [PMID: 38567867 DOI: 10.1021/acsnano.3c09221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Interferometric scattering microscopy (iSCAT) has rapidly developed as a quantitative tool for the label-free detection of single macromolecules and nanoparticles. In practice, this measurement records the interferometric scattering signal of individual nanoparticles in solution as they land and stick on a coverslip, exhibiting an intensity that varies linearly with particle volume and an adsorption rate that reflects the solution-phase transport kinetics of the system. Together, such measurements provide a multidimensional gauge of the particle size and concentration in solution over time. However, the landing kinetics of particles in solution also manifest a measurement frequency limitation imposed by the slow long-range mobility of particle diffusion to the measurement interface. Here we introduce an effective means to overcome the inherent diffusion-controlled sampling limitation of spontaneous mass photometry. We term this methodology electrophoretic deposition interferometric scattering microscopy (EPD-iSCAT). This approach uses a coverslip supporting a conductive thin film of indium tin oxide (ITO). Charging this ITO film to a potential of around +1 V electrophoretically draws charged nanoparticles from solution and binds them in the focal plane of the microscope. Regulating this potential offers a direct means of controlling particle deposition. Thus, we find for a 0.1 nM solution of 50 nm polystyrene nanoparticles that the application of +1 V to an EPD-iSCAT coverslip assembly drives an electrophoretic deposition rate constant of 1.7 s-1 μm-2 nM-1. Removal of the potential causes deposition to cease. This user control of EPD-iSCAT affords a means to apply single-molecule mass photometry to monitor long-term changes in solution, owing to slow kinetic processes. In contrast with conventional coverslips chemically derivatized with charged thin films, EPD-iSCAT maintains a deposition rate that varies linearly with the bulk concentration.
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Affiliation(s)
- Matthew D Kowal
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Teresa M Seifried
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Carraugh C Brouwer
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Hooman Tavakolizadeh
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Erik Olsén
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Edward Grant
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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Bernacchia L, Paris A, Gupta A, Charman RJ, McGreig J, Wass MN, Kad NM. Identification of a novel DNA repair inhibitor using an in silico driven approach shows effective combinatorial activity with genotoxic agents against multidrug-resistant Escherichia coli. Protein Sci 2024; 33:e4948. [PMID: 38501485 PMCID: PMC10949335 DOI: 10.1002/pro.4948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/30/2024] [Accepted: 02/12/2024] [Indexed: 03/20/2024]
Abstract
Increasing antimicrobial drug resistance represents a global existential threat. Infection is a particular problem in immunocompromised individuals, such as patients undergoing cancer chemotherapy, due to the targeting of rapidly dividing cells by antineoplastic agents. We recently developed a strategy that targets bacterial nucleotide excision DNA repair (NER) to identify compounds that act as antimicrobial sensitizers specific for patients undergoing cancer chemotherapy. Building on this, we performed a virtual drug screening of a ~120,000 compound library against the key NER protein UvrA. From this, numerous target compounds were identified and of those a candidate compound, Bemcentinib (R428), showed a strong affinity toward UvrA. This NER protein possesses four ATPase sites in its dimeric state, and we found that Bemcentinib could inhibit UvrA's ATPase activity by ~90% and also impair its ability to bind DNA. As a result, Bemcentinib strongly diminishes NER's ability to repair DNA in vitro. To provide a measure of in vivo activity we discovered that the growth of Escherichia coli MG1655 was significantly inhibited when Bemcentinib was combined with the DNA damaging agent 4-NQO, which is analogous to UV. Using the clinically relevant DNA-damaging antineoplastic cisplatin in combination with Bemcentinib against the urological sepsis-causing E. coli strain EC958 caused complete growth inhibition. This study offers a novel approach for the potential development of new compounds for use as adjuvants in antineoplastic therapy.
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Affiliation(s)
| | - Antoine Paris
- School of Biological SciencesUniversity of KentCanterburyUK
| | - Arya Gupta
- School of Biological SciencesUniversity of KentCanterburyUK
| | | | - Jake McGreig
- School of Biological SciencesUniversity of KentCanterburyUK
| | - Mark N. Wass
- School of Biological SciencesUniversity of KentCanterburyUK
| | - Neil M. Kad
- School of Biological SciencesUniversity of KentCanterburyUK
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Bernacchia L, Gupta A, Paris A, Moores AA, Kad NM. Developing novel antimicrobials by combining cancer chemotherapeutics with bacterial DNA repair inhibitors. PLoS Pathog 2023; 19:e1011875. [PMID: 38060607 PMCID: PMC10729960 DOI: 10.1371/journal.ppat.1011875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 12/19/2023] [Accepted: 11/28/2023] [Indexed: 12/20/2023] Open
Abstract
Cancer chemotherapeutics kill rapidly dividing cells, which includes cells of the immune system. The resulting neutropenia predisposes patients to infection, which delays treatment and is a major cause of morbidity and mortality. To tackle this problem, we have isolated several compounds that inhibit bacterial DNA repair, alone they are non-toxic, however in combination with DNA damaging anti-cancer drugs, they prevent bacterial growth. These compounds were identified through screening of an FDA-approved drug library in the presence of the anti-cancer compound cisplatin. Using a series of triage tests, the screen was reduced to a handful of drugs that were tested for specific activity against bacterial nucleotide excision DNA repair (NER). Five compounds emerged, of which three possess promising antimicrobial properties including cell penetrance, and the ability to block replication in a multi-drug resistant clinically relevant E. coli strain. This study suggests that targeting NER could offer a new therapeutic approach tailor-made for infections in cancer patients, by combining cancer chemotherapy with an adjuvant that targets DNA repair.
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Affiliation(s)
- Lorenzo Bernacchia
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Arya Gupta
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | - Antoine Paris
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
| | | | - Neil M. Kad
- School of Biosciences, University of Kent, Canterbury, Kent, United Kingdom
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Zhang Z, Qin J, Wang Z, Chen F, Liao X, Hu X, Dong L. Sodium copper chlorophyll mediated photodynamic treatment inactivates Escherichia coli via oxidative damage. Food Res Int 2022; 157:111472. [PMID: 35761703 DOI: 10.1016/j.foodres.2022.111472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/22/2022] [Accepted: 06/04/2022] [Indexed: 11/17/2022]
Abstract
Photodynamic technology (PDT) is an emerging non-thermal processing technique, however, due to a lack of edible photosensitizers, its application to the food industry is limited. To better understand sodium copper chlorophyll (SCC) feasibility as a photosensitizer, we analyzed the effects of PDT-SCC on Escherichia coli O157:H7 inactivation using different lighting times (15, 30, 45, 60, and 75 min), lighting power (30, 60, 90, 120, and 150 W), and SCC concentrations (2, 4, 6, 8, and 10 mM). We showed that bactericidal effects depended on all three parameters, but the most suitable sterilization condition for E. coli occurred at 10 mM SCC, for 60 min at 120 W. We also investigated cell morphology, reactive oxygen species (ROS) production, the activity of three oxidative response enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX)), and ompA, ompF, uvrA, and recA expression. When compared with the control group, PDT-SCC destroyed bacterial morphology, increased ROS production, decreased antioxidant enzyme activity (SOD, CAT, and GPX), down-regulated membrane protein gene expression, including ompA and ompF, and up-regulated the DNA damage-repair related genes, uvrA and recA. Thus, bacterial rupture caused by oxidative damage could be the main mechanism underpinning PDT-SCC action.
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Affiliation(s)
- Zequn Zhang
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Jianran Qin
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Zhe Wang
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Fang Chen
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Xiaojun Liao
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Xiaosong Hu
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Li Dong
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China.
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