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Wray R, Iscla I, Blount P. Curcumin activation of a bacterial mechanosensitive channel underlies its membrane permeability and adjuvant properties. PLoS Pathog 2021; 17:e1010198. [PMID: 34941967 PMCID: PMC8769312 DOI: 10.1371/journal.ppat.1010198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/19/2022] [Accepted: 12/14/2021] [Indexed: 11/18/2022] Open
Abstract
Curcumin, a natural compound isolated from the rhizome of turmeric, has been shown to have antibacterial properties. It has several physiological effects on bacteria including an apoptosis-like response involving RecA, membrane permeabilization, inhibiting septation, and it can also work synergistically with other antibiotics. The mechanism by which curcumin permeabilizes the bacterial membrane has been unclear. Most bacterial species contain a Mechanosensitive channel of large conductance, MscL, which serves the function of a biological emergency release valve; these large-pore channels open in response to membrane tension from osmotic shifts and, to avoid cell lysis, allow the release of solutes from the cytoplasm. Here we show that the MscL channel underlies the membrane permeabilization by curcumin as well as its synergistic properties with other antibiotics, by allowing access of antibiotics to the cytoplasm; MscL also appears to have an inhibitory role in septation, which is enhanced when activated by curcumin.
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Affiliation(s)
- Robin Wray
- Department of Physiology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Irene Iscla
- Department of Physiology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Paul Blount
- Department of Physiology, UT Southwestern Medical Center, Dallas, Texas, United States of America
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Cox CD, Bavi N, Martinac B. Biophysical Principles of Ion-Channel-Mediated Mechanosensory Transduction. Cell Rep 2020; 29:1-12. [PMID: 31577940 DOI: 10.1016/j.celrep.2019.08.075] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/09/2019] [Accepted: 08/22/2019] [Indexed: 01/12/2023] Open
Abstract
Recent rapid progress in the field of mechanobiology has been driven by novel emerging tools and methodologies and growing interest from different scientific disciplines. Specific progress has been made toward understanding how cell mechanics is linked to intracellular signaling and the regulation of gene expression in response to a variety of mechanical stimuli. There is a direct link between the mechanoreceptors at the cell surface and intracellular biochemical signaling, which in turn controls downstream effector molecules. Among the mechanoreceptors in the cell membrane, mechanosensitive (MS) ion channels are essential for the ultra-rapid (millisecond) transduction of mechanical stimuli into biologically relevant signals. The three decades of research on mechanosensitive channels resulted in the formulation of two basic principles of mechanosensitive channel gating: force-from-lipids and force-from-filament. In this review, we revisit the biophysical principles that underlie the innate force-sensing ability of mechanosensitive channels as contributors to the force-dependent evolution of life forms.
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Affiliation(s)
- Charles D Cox
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Navid Bavi
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia; St. Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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Wray R, Herrera N, Iscla I, Wang J, Blount P. An agonist of the MscL channel affects multiple bacterial species and increases membrane permeability and potency of common antibiotics. Mol Microbiol 2019; 112:896-905. [PMID: 31177589 DOI: 10.1111/mmi.14325] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/06/2019] [Indexed: 12/18/2022]
Abstract
The bacterial MscL channel normally functions as an emergency release valve discharging cytoplasmic solutes upon osmotic stress. The channel opens and passes molecules up to 30 Å and its pore is the largest of any gated channel. Opening the MscL pore inappropriately is detrimental to the bacterial cell, suggesting MscL as a potential novel drug target. A small-molecule compound, 011A, has been shown to increase sensitivity of the Escherichia coli MscL channel, slow growth, and even decrease viability of quiescent cultures. The mscL gene is highly conserved and found in the vast majority of bacterial species, including pathogens. Here, we test the hypothesis that 011A can influence the growth and viability of other bacterial species, specifically Staphylococcus aureus and Mycobacterium smegmatis, in a MscL-dependent manner. Furthermore, we demonstrate that the 011A compound can increase potency of other antibiotics, presumably by permeabilizing the membrane and allowing easier access of the antibiotic into the cytoplasm. Thus, MscL activators have potential as novel broad-spectrum antibiotics or adjuvants that work with antibiotics to selectively allow passage across bacterial membranes.
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Affiliation(s)
- Robin Wray
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
| | - Nadia Herrera
- Division of Chemistry and Chemical Engineering 114-96, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Irene Iscla
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
| | - Junmei Wang
- Department of Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA, USA
| | - Paul Blount
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
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Yang LM, Zheng H, Ratnakar JS, Adebesin BY, Do QN, Kovacs Z, Blount P. Engineering a pH-Sensitive Liposomal MRI Agent by Modification of a Bacterial Channel. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1704256. [PMID: 29638039 PMCID: PMC6140348 DOI: 10.1002/smll.201704256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/31/2018] [Indexed: 06/08/2023]
Abstract
MscL is a bacterial mechanosensitive channel that serves as a cellular emergency release valve, protecting the cell from lysis upon a drop in external osmolarity. The channel has an extremely large pore (30 Å) and can be purified and reconstituted into artificial membranes. Moreover, MscL is modified to open in response to alternative external stimuli including changes in pH. These properties suggest this channel's potential as a triggered "nanopore" for localized release of vesicular contents such as magnetic resonance imaging (MRI) contrast agents and drugs. Toward this end, several variants of pH-triggered MscL nanovalves are engineered. Stealth vesicles previously been shown to evade normal in vivo clearance and passively accumulate in inflamed and malignant tissues are reconstituted. These vesicles are loaded with 1,4,7,10-tetraazacyclododecane tetraacetic acid gadolinium complex (Gd-DOTA), an MRI contrast reagent, and the resulting nanodevices tested for their ability to release Gd-DOTA as evidenced by enhancement of the longitudinal relaxation rate (R1 ) of the bulk water proton spins. Nanovalves that are responsive to physiological pH changes are identified, but differ in sensitivity and efficacy, thus giving an array of nanovalves that could potentially be useful in different settings. These triggered nanodevices may be useful in delivering both diagnostic and therapeutic agents.
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Affiliation(s)
- Li-Min Yang
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Hui Zheng
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - James S Ratnakar
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Bukola Y Adebesin
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Quyen N Do
- Department of Radiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Zoltan Kovacs
- Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
| | - Paul Blount
- Department of Physiology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
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Sciscione F, Pucci C, La Mesa C. Binding of a protein or a small polyelectrolyte onto synthetic vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:2810-2819. [PMID: 24564353 DOI: 10.1021/la500199w] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Catanionic vesicles were prepared by mixing nonstoichiometric amounts of sodium bis(2-ethylhexyl) sulfosuccinate and dioctyldimethylammonium bromide in water. Depending on the concentration and mole ratios between the surfactants, catanionic vesicular aggregates are formed. They have either negative or positive charges in excess and are endowed with significant thermodynamic and kinetic stability. Vesicle characterization was performed by dynamic light scattering and electrophoretic mobility. It was inferred that vesicle size scales in inverse proportion with its surface charge density and diverges as the latter quantity approaches zero and/or the mole ratio equals unity. Therefore, both variables are controlled by the anionic/cationic mole ratio. Small-angle X-ray scattering, in addition, indicates that vesicles are unilamellar. Selected anionic vesicular systems were reacted with poly-L-lysine hydrobromide or lysozyme. Polymer binding continues until complete neutralization of the negatively charged sites on the vesicles surface is attained, as inferred by electrophoretic mobility. Lipoplexes are formed as a result of significant electrostatic interactions between cationic polyelectrolytes and negatively charged vesicles.
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Affiliation(s)
- Fabiola Sciscione
- Department of Chemistry, Cannizzaro Building, La Sapienza University , P.le A. Moro 5, I-00185 Rome, Italy
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