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Fumadó Navarro J, Lomora M. Mechanoresponsive Drug Delivery Systems for Vascular Diseases. Macromol Biosci 2023; 23:e2200466. [PMID: 36670512 DOI: 10.1002/mabi.202200466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/16/2023] [Indexed: 01/22/2023]
Abstract
Mechanoresponsive drug delivery systems (DDS) have emerged as promising candidates to improve the current effectiveness and lower the side effects typically associated with direct drug administration in the context of vascular diseases. Despite tremendous research efforts to date, designing drug delivery systems able to respond to mechanical stimuli to potentially treat these diseases is still in its infancy. By understanding relevant biological forces emerging in healthy and pathological vascular endothelium, it is believed that better-informed design strategies can be deduced for the fabrication of simple-to-complex macromolecular assemblies capable of sensing mechanical forces. These responsive systems are discussed through insights into essential parameter design (composition, size, shape, and aggregation state) , as well as their functionalization with (macro)molecules that are intrinsically mechanoresponsive (e.g., mechanosensitive ion channels and mechanophores). Mechanical forces, including the pathological shear stress and exogenous stimuli (e.g., ultrasound, magnetic fields), used for the activation of mechanoresponsive DDS are also introduced, followed by in vitro and in vivo experimental models used to investigate and validate such novel therapies. Overall, this review aims to propose a fresh perspective through identified challenges and proposed solutions that could be of benefit for the further development of this exciting field.
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Affiliation(s)
- Josep Fumadó Navarro
- School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
- CÚRAM, SFI Research Centre for Medical Devices, University of Galway, Upper Newcastle, Galway, H91 W2TY, Ireland
| | - Mihai Lomora
- School of Biological and Chemical Sciences, University of Galway, University Road, Galway, H91 TK33, Ireland
- CÚRAM, SFI Research Centre for Medical Devices, University of Galway, Upper Newcastle, Galway, H91 W2TY, Ireland
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2
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Xing Y, Dorey A, Howorka S. Multi-Stimuli-Responsive and Mechano-Actuated Biomimetic Membrane Nanopores Self-Assembled from DNA. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2300589. [PMID: 37029712 DOI: 10.1002/adma.202300589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/31/2023] [Indexed: 06/04/2023]
Abstract
In bioinspired design, biological templates are mimicked in structure and function by highly controllable synthetic means. Of interest are static barrel-like nanopores that enable molecular transport across membranes for use in biosensing, sequencing, and biotechnology. However, biological ion channels offer additional functions such as dynamic changes of the entire pore shape between open and closed states, and triggering of dynamic processes with biochemical and physical stimuli. To better capture this complexity, this report presents multi-stimuli and mechano-responsive biomimetic nanopores which are created with DNA nanotechnology. The nanopores switch between open and closed states, whereby specific binding of DNA and protein molecules as stimuli locks the pores in the open state. Furthermore, the physical stimulus of high transmembrane voltage switches the pores into a closed state. In addition, the pore diameters are larger and more tunable than those of natural templates. These multi-stimuli-responsive and mechanically actuated nanopores mimic several aspects of complex biological channels yet offer easier control over pore size, shape and stimulus response. The designer pores are expected to be applied in biosensing and synthetic biology.
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Affiliation(s)
- Yongzheng Xing
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Adam Dorey
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
| | - Stefan Howorka
- Department of Chemistry & Institute of Structural and Molecular Biology, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
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3
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Bavi O, Zhou Z, Bavi N, Mehdi Vaez Allaei S, Cox CD, Martinac B. Asymmetric effects of amphipathic molecules on mechanosensitive channels. Sci Rep 2022; 12:9976. [PMID: 35705645 PMCID: PMC9200802 DOI: 10.1038/s41598-022-14446-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/06/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanosensitive (MS) ion channels are primary transducers of mechanical force into electrical and/or chemical intracellular signals. Many diverse MS channel families have been shown to respond to membrane forces. As a result of this intimate relationship with the membrane and proximal lipids, amphipathic compounds exert significant effects on the gating of MS channels. Here, we performed all-atom molecular dynamics (MD) simulations and employed patch-clamp recording to investigate the effect of two amphipaths, Fluorouracil (5-FU) a chemotherapy agent, and the anaesthetic trifluoroethanol (TFE) on structurally distinct mechanosensitive channels. We show that these amphipaths have a profound effect on the bilayer order parameter as well as transbilayer pressure profile. We used bacterial mechanosensitive channels (MscL/MscS) and a eukaryotic mechanosensitive channel (TREK-1) as force-from-lipids reporters and showed that these amphipaths have differential effects on these channels depending on the amphipaths' size and shape as well as which leaflet of the bilayer they incorporate into. 5-FU is more asymmetric in shape and size than TFE and does not penetrate as deep within the bilayer as TFE. Thereby, 5-FU has a more profound effect on the bilayer and channel activity than TFE at much lower concentrations. We postulate that asymmetric effects of amphipathic molecules on mechanosensitive membrane proteins through the bilayer represents a general regulatory mechanism for these proteins.
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Affiliation(s)
- Omid Bavi
- grid.444860.a0000 0004 0600 0546Department of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz, Iran
| | - Zijing Zhou
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia
| | - Navid Bavi
- grid.170205.10000 0004 1936 7822Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL USA
| | - S. Mehdi Vaez Allaei
- grid.46072.370000 0004 0612 7950Department of Physics, University of Tehran, 1439955961 Tehran, Iran
| | - Charles D. Cox
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia ,grid.1005.40000 0004 4902 0432Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW 2010 Australia
| | - B. Martinac
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia ,grid.1005.40000 0004 4902 0432Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW 2010 Australia
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4
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Miles L, Powell J, Kozak C, Song Y. Mechanosensitive Ion Channels, Axonal Growth, and Regeneration. Neuroscientist 2022:10738584221088575. [PMID: 35414308 PMCID: PMC9556659 DOI: 10.1177/10738584221088575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cells sense and respond to mechanical stimuli by converting those stimuli into biological signals, a process known as mechanotransduction. Mechanotransduction is essential in diverse cellular functions, including tissue development, touch sensitivity, pain, and neuronal pathfinding. In the search for key players of mechanotransduction, several families of ion channels were identified as being mechanosensitive and were demonstrated to be activated directly by mechanical forces in both the membrane bilayer and the cytoskeleton. More recently, Piezo ion channels were discovered as a bona fide mechanosensitive ion channel, and its characterization led to a cascade of research that revealed the diverse functions of Piezo proteins and, in particular, their involvement in neuronal repair.
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Affiliation(s)
- Leann Miles
- The Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Jackson Powell
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Casey Kozak
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Yuanquan Song
- The Graduate Group in Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA.,Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Immadisetty K, Polasa A, Shelton R, Moradi M. Elucidating the molecular basis of spontaneous activation in an engineered mechanosensitive channel. Comput Struct Biotechnol J 2022; 20:2539-2550. [PMID: 35685356 PMCID: PMC9156883 DOI: 10.1016/j.csbj.2022.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 12/11/2022] Open
Abstract
Mechanosensitive channel of large conductance (MscL) detects and responds to changes in the pressure profile of cellular membranes and transduces the mechanical energy into electrical and/or chemical signals. MscL can be activated using ultrasonic or chemical activation methods to improve the absorption of medicines and bioactive compounds into cells. However, re-engineering chemical signals such as pH change can trigger channel activation in MscL. This study elucidates the activation mechanism of an engineered MscL at an atomic level through a combination of equilibrium and non-equilibrium (NE) molecular dynamics (MD) simulations. Comparing the wild-type (WT) and engineered MscL activation processes suggests that the two systems are likely associated with different active states and different transition pathways. These findings indicate that (1) periplasmic loops play a key role in the activation process of MscL, (2) the loss of various backbone-backbone hydrogen bonds and salt bridge interactions in the engineered MscL channel causes the spontaneous opening of the channel, and (3) the most significant interactions lost during the activation process are between the transmembrane helices 1 and 2 in engineered MscL channel. The orientation-based biasing approach for producing and optimizing an open MscL model used in this work is a promising way to characterize unknown protein functional states and investigate the activation processes in ion channels and transmembrane proteins in general. This work paves the way for a computational framework for engineering more efficient pH-sensing mechanosensitive channels.
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Affiliation(s)
- Kalyan Immadisetty
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Adithya Polasa
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Reid Shelton
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
| | - Mahmoud Moradi
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, United States
- Corresponding author.
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6
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The challenges and prospects of Escherichia coli as an organic acid production host under acid stress. Appl Microbiol Biotechnol 2021; 105:8091-8107. [PMID: 34617140 DOI: 10.1007/s00253-021-11577-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Organic acids have a wide range of applications and have attracted the attention of many industries, and their large-scale applications have led fermentation production to low-cost development. Among them, the microbial fermentation method, especially using Escherichia coli as the production host, has the advantages of fast growth and low energy consumption, and has gradually shown better advantages and prospects in organic acid fermentation production. IMPORTANCE However, when the opportunity comes, the acidified environment caused by the acid products accumulated during the fermentation process also challenges E. coli. The acid sensitivity of E. coli is a core problem that needs to be solved urgently. The addition of neutralizers in traditional operations led to the emergence of osmotic stress inadvertently, the addition of strong acid substances to recover products in the salt state not only increases production costs, but the discharged sewage is also harmful to the environment. ELABORATION This article summarizes the current status of the application of E. coli in the production of organic acids, and based on the impact of acid stress on the physiological state of cells and the impact of industrial production profits, put forward some new conjectures that can make up for the deficiencies in existing research and application. IMPLICATION At this point, the diversified transformation of E. coli has become a chassis microbe that is more suitable for industrial fermentation, enhancing industrial application value. KEY POINTS • E. coli is a potential host for high value-added organic acids production. • Classify the damage mechanism and coping strategies of E. coli when stimulated by acid molecules. • Multi-dimensional expansion tools are needed to create acid-resistant E. coli chassis.
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7
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Abstract
Mechanosensing is a key feature through which organisms can receive inputs from the environment and convert them into specific functional and behavioral outputs. Mechanosensation occurs in many cells and tissues, regulating a plethora of molecular processes based on the distribution of forces and stresses both at the cell membrane and at the intracellular organelles levels, through complex interactions between cells’ microstructures, cytoskeleton, and extracellular matrix. Although several primary and secondary mechanisms have been shown to contribute to mechanosensation, a fundamental pathway in simple organisms and mammals involves the presence of specialized sensory neurons and the presence of different types of mechanosensitive ion channels on the neuronal cell membrane. In this contribution, we present a review of the main ion channels which have been proven to be significantly involved in mechanotransduction in neurons. Further, we discuss recent studies focused on the biological mechanisms and modeling of mechanosensitive ion channels’ gating, and on mechanotransduction modeling at different scales and levels of details.
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8
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Rajeshwar T R, Anishkin A, Sukharev S, Vanegas JM. Mechanical Activation of MscL Revealed by a Locally Distributed Tension Molecular Dynamics Approach. Biophys J 2020; 120:232-242. [PMID: 33333032 DOI: 10.1016/j.bpj.2020.11.2274] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/20/2020] [Accepted: 11/30/2020] [Indexed: 02/02/2023] Open
Abstract
Membrane tension perceived by mechanosensitive (MS) proteins mediates cellular responses to mechanical stimuli and osmotic stresses, and it also guides multiple biological functions including cardiovascular control and development. In bacteria, MS channels function as tension-activated pores limiting excessive turgor pressure, with MS channel of large conductance (MscL) acting as an emergency release valve preventing cell lysis. Previous attempts to simulate gating transitions in MscL by either directly applying steering forces to the protein or by increasing the whole-system tension were not fully successful and often disrupted the integrity of the system. We present a novel, to our knowledge, locally distributed tension molecular dynamics (LDT-MD) simulation method that allows application of forces continuously distributed among lipids surrounding the channel using a specially constructed collective variable. We report reproducible and reversible transitions of MscL to the open state with measured parameters of lateral expansion and conductivity that exactly satisfy experimental values. The LDT-MD method enables exploration of the MscL-gating process with different pulling velocities and variable tension asymmetry between the inner and outer membrane leaflets. We use LDT-MD in combination with well-tempered metadynamics to reconstruct the tension-dependent free-energy landscape for the opening transition in MscL. The flexible definition of the LDT collective variable allows general application of our method to study mechanical activation of any membrane-embedded protein.
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Affiliation(s)
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, Maryland
| | - Juan M Vanegas
- Department of Physics, University of Vermont, Burlington, Vermont.
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9
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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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10
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Carniello V, Peterson BW, van der Mei HC, Busscher HJ. Role of adhesion forces in mechanosensitive channel gating in Staphylococcus aureus adhering to surfaces. NPJ Biofilms Microbiomes 2020; 6:31. [PMID: 32826897 PMCID: PMC7442641 DOI: 10.1038/s41522-020-00141-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 07/30/2020] [Indexed: 01/18/2023] Open
Abstract
Mechanosensitive channels in bacterial membranes open or close in response to environmental changes to allow transmembrane transport, including antibiotic uptake and solute efflux. In this paper, we hypothesize that gating of mechanosensitive channels is stimulated by forces through which bacteria adhere to surfaces. Hereto, channel gating is related with adhesion forces to different surfaces of a Staphylococcus aureus strain and its isogenic ΔmscL mutant, deficient in MscL (large) channel gating. Staphylococci becoming fluorescent due to uptake of calcein, increased with adhesion force and were higher in the parent strain (66% when adhering with an adhesion force above 4.0 nN) than in the ΔmscL mutant (40% above 1.2 nN). This suggests that MscL channels open at a higher critical adhesion force than at which physically different, MscS (small) channels open and contribute to transmembrane transport. Uptake of the antibiotic dihydrostreptomycin was monitored by staphylococcal killing. The parent strain exposed to dihydrostreptomycin yielded a CFU reduction of 2.3 log-units when adhering with an adhesion force above 3.5 nN, but CFU reduction remained low (1.0 log-unit) in the mutant, independent of adhesion force. This confirms that large channels open at a higher critical adhesion-force than small channels, as also concluded from calcein transmembrane transport. Collectively, these observations support our hypothesis that adhesion forces to surfaces play an important role, next to other established driving forces, in staphylococcal channel gating. This provides an interesting extension of our understanding of transmembrane antibiotic uptake and solute efflux in infectious staphylococcal biofilms in which bacteria experience adhesion forces from a wide variety of surfaces, like those of other bacteria, tissue cells, or implanted biomaterials.
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Affiliation(s)
- Vera Carniello
- Department of BioMedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Brandon W Peterson
- Department of BioMedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands.
| | - Henny C van der Mei
- Department of BioMedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
| | - Henk J Busscher
- Department of BioMedical Engineering, University of Groningen and University Medical Center Groningen, Groningen, Netherlands
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11
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Winkeljohn CM, Himberg B, Vanegas JM. Balance of Solvent and Chain Interactions Determines the Local Stress State of Simulated Membranes. J Phys Chem B 2020; 124:6963-6971. [DOI: 10.1021/acs.jpcb.0c03937] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Conner M. Winkeljohn
- Department of Physics, University of Vermont, Burlington, Vermont 05405, United States
| | - Benjamin Himberg
- Materials Science Graduate Program, University of Vermont, Burlington, Vermont 05405, United States
| | - Juan M. Vanegas
- Department of Physics, University of Vermont, Burlington, Vermont 05405, United States
- Materials Science Graduate Program, University of Vermont, Burlington, Vermont 05405, United States
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12
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Ridone P, Vassalli M, Martinac B. Piezo1 mechanosensitive channels: what are they and why are they important. Biophys Rev 2019; 11:795-805. [PMID: 31494839 PMCID: PMC6815293 DOI: 10.1007/s12551-019-00584-5] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 08/27/2019] [Indexed: 12/12/2022] Open
Abstract
Mechanosensitive (MS) ion channels are integral membrane proteins which play a crucial role in fast signaling during mechanosensory transduction processes in living cells. They are ubiquitous and old in the evolutionary sense, given their presence in cells from all three kingdoms of life found on Earth, including bacterial, archaeal, and eukaryotic organisms. As molecular transducers of mechanical force, MS channels are activated by mechanical stimuli exerted on cellular membranes, upon which they rapidly and efficiently convert these stimuli into electrical, osmotic, and/or chemical intracellular signals. Most of what we know about the gating mechanisms of MS channels comes from the work carried out on bacterial channels. However, recent progress resulting from identification and structural information of eukaryotic K2P-type TREK and TRAAK as well as Piezo1 and Piezo2 MS channels has greatly contributed to our understanding of the common biophysical principles underlying the gating mechanism and evolutionary origins of these fascinating membrane proteins. Using Piezo1 channels as an example, we briefly describe in this review what we have learned about their biophysics, physiological functions, and potential roles in "mechanopathologies."
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Affiliation(s)
- Pietro Ridone
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, 405 Liverpool St, Darlinghurst, NSW, 2010, Australia
- School of Biotechnology and Biomolecular Science, University of New South Wales, Kensington, NSW, 2052, Australia
| | - Massimo Vassalli
- Institute of Biophysics, National Research Council, Genoa, Italy
| | - Boris Martinac
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, 405 Liverpool St, Darlinghurst, NSW, 2010, Australia.
- St Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, 2010, Australia.
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Li H, Xu J, Shen ZS, Wang GM, Tang M, Du XR, Lv YT, Wang JJ, Zhang FF, Qi Z, Zhang Z, Sokabe M, Tang QY. The neuropeptide GsMTx4 inhibits a mechanosensitive BK channel through the voltage-dependent modification specific to mechano-gating. J Biol Chem 2019; 294:11892-11909. [PMID: 31201274 DOI: 10.1074/jbc.ra118.005511] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
The cardiac mechanosensitive BK (Slo1) channels are gated by Ca2+, voltage, and membrane stretch. The neuropeptide GsMTx4 is a selective inhibitor of mechanosensitive (MS) channels. It has been reported to suppress stretch-induced cardiac fibrillation in the heart, but the mechanism underlying the specificity and even the targeting channel(s) in the heart remain elusive. Here, we report that GsMTx4 inhibits a stretch-activated BK channel (SAKcaC) in the heart through a modulation specific to mechano-gating. We show that membrane stretching increases while GsMTx4 decreases the open probability (P o) of SAKcaC. These effects were mostly abolished by the deletion of the STREX axis-regulated (STREX) exon located between RCK1 and RCK2 domains in BK channels. Single-channel kinetics analysis revealed that membrane stretch activates SAKcaC by prolonging the open-time duration (τO) and shortening the closed-time constant (τC). In contrast, GsMTx4 reversed the effects of membrane stretch, suggesting that GsMTx4 inhibits SAKcaC activity by interfering with mechano-gating of the channel. Moreover, GsMTx4 exerted stronger efficacy on SAKcaC under membrane-hyperpolarized/resting conditions. Molecular dynamics simulation study revealed that GsMTx4 appeared to have the ability to penetrate deeply within the bilayer, thus generating strong membrane deformation under the hyperpolarizing/resting conditions. Immunostaining results indicate that BK variants containing STREX are also expressed in mouse ventricular cardiomyocytes. Our results provide common mechanisms of peptide actions on MS channels and may give clues to therapeutic suppression of cardiac arrhythmias caused by excitatory currents through MS channels under hyper-mechanical stress in the heart.
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Affiliation(s)
- Hui Li
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Jie Xu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zhong-Shan Shen
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Guang-Ming Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Mingxi Tang
- Department of Pathology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Xiang-Rong Du
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Yan-Tian Lv
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Jing-Jing Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Fei-Fei Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zhi Qi
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiamen 361102, China
| | - Zhe Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Masahiro Sokabe
- ICORP Cell Mechanosensing, Japan Science and Technology Agency, Nagoya 466-8550, Japan .,Mechanobiology Laboratory, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Japan.,Department of Physiology, Nagoya University, Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Qiong-Yao Tang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China .,ICORP Cell Mechanosensing, Japan Science and Technology Agency, Nagoya 466-8550, Japan
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14
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Kim RC, Le D, Ma K, Heath-Heckman EAC, Whitehorn N, Kristan WB, Weisblat DA. Behavioral analysis of substrate texture preference in a leech, Helobdella austinensis. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:191-202. [PMID: 30721348 DOI: 10.1007/s00359-019-01317-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/18/2019] [Accepted: 01/22/2019] [Indexed: 01/02/2023]
Abstract
Leeches in the wild are often found on smooth surfaces, such as vegetation, smooth rocks or human artifacts such as bottles and cans, thus exhibiting what appears to be a "substrate texture preference". Here, we have reproduced this behavior under controlled circumstances, by allowing leeches to step about freely on a range of silicon carbide substrates (sandpaper). To begin to understand the neural mechanisms underlying this texture preference behavior, we have determined relevant parameters of leech behavior both on uniform substrates of varying textures, and in a behavior choice paradigm in which the leech is confronted with a choice between rougher and smoother substrate textures at each step. We tested two non-exclusive mechanisms which could produce substrate texture preference: (1) a Differential Diffusion mechanism, in which a leech is more likely to stop moving on a smooth surface than on a rough one, and (2) a Smoothness Selection mechanism, in which a leech is more likely to attach its front sucker (prerequisite for taking a step) to a smooth surface than to a rough one. We propose that both mechanisms contribute to the texture preference exhibited by leeches.
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Affiliation(s)
- Rachel C Kim
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA
| | - Dylan Le
- Division of Biological Sciences, University of California San Diego, 3119 Pacific Hall, La Jolla, CA, 92093, USA
| | - Kenny Ma
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA
| | - Elizabeth A C Heath-Heckman
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Nathan Whitehorn
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - William B Kristan
- Division of Biological Sciences, University of California San Diego, 3119 Pacific Hall, La Jolla, CA, 92093, USA
| | - David A Weisblat
- Department of Molecular and Cell Biology, University of California, 385 LSA, Berkeley, CA, 94720-3200, USA.
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15
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Liu X, Wang J, Sun L. Structure of the hyperosmolality-gated calcium-permeable channel OSCA1.2. Nat Commun 2018; 9:5060. [PMID: 30498218 PMCID: PMC6265326 DOI: 10.1038/s41467-018-07564-5] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/09/2018] [Indexed: 01/08/2023] Open
Abstract
In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade initiated by cytosolic calcium concentration elevation. Members of the OSCA family in Arabidopsis thaliana, identified as the hyperosmolality-gated calcium-permeable channels, have been suggested to play a key role during the initial phase of hyperosmotic stress response. Here, we report the atomic structure of Arabidopsis OSCA1.2 determined by single-particle cryo-electron microscopy. It contains 11 transmembrane helices and forms a homodimer. It is in an inactivated state, and the pore-lining residues are clearly identified. Its cytosolic domain contains a RNA recognition motif and two unique long helices. The linker between these two helices forms an anchor in the lipid bilayer and may be essential to osmosensing. The structure of AtOSCA1.2 serves as a platform for the study of the mechanism underlying osmotic stress responses and mechanosensing. In plants, hyperosmolality stimuli triggers opening of the osmosensitive channels, leading to a rapid downstream signaling cascade. Here, the authors solve the cryo-EM structure of an osmosensitive channel from Arabidopsis OSCA1.2 in its inactivated state.
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Affiliation(s)
- Xin Liu
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 230027, Hefei, China
| | - Jiawei Wang
- State Key Laboratory of Membrane Biology, Beijing Advanced Innovation Centre for Structural Biology, School of Life Sciences, Tsinghua University, 100084, Beijing, China.
| | - Linfeng Sun
- Hefei National Laboratory for Physical Sciences at Microscale, School of Life Sciences, University of Science and Technology of China, 230027, Hefei, China. .,CAS Centre for Excellence in Molecular Cell Science, University of Science and Technology of China, Chinese Academy of Sciences, 230027, Hefei, China.
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16
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Carniello V, Peterson BW, van der Mei HC, Busscher HJ. Physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth. Adv Colloid Interface Sci 2018; 261:1-14. [PMID: 30376953 DOI: 10.1016/j.cis.2018.10.005] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/08/2018] [Accepted: 10/22/2018] [Indexed: 02/07/2023]
Abstract
Biofilm formation is initiated by adhesion of individual bacteria to a surface. However, surface adhesion alone is not sufficient to form the complex community architecture of a biofilm. Surface-sensing creates bacterial awareness of their adhering state on the surface and is essential to initiate the phenotypic and genotypic changes that characterize the transition from initial bacterial adhesion to a biofilm. Physico-chemistry has been frequently applied to explain initial bacterial adhesion phenomena, including bacterial mass transport, role of substratum surface properties in initial adhesion and the transition from reversible to irreversible adhesion. However, also emergent biofilm properties, such as production of extracellular-polymeric-substances (EPS), can be surface-programmed. This review presents a four-step, comprehensive description of the role of physico-chemistry from initial bacterial adhesion to surface-programmed biofilm growth: (1) bacterial mass transport towards a surface, (2) reversible bacterial adhesion and (3) transition to irreversible adhesion and (4) cell wall deformation and associated emergent properties. Bacterial transport mostly occurs from sedimentation or convective-diffusion, while initial bacterial adhesion can be described by surface thermodynamic and Derjaguin-Landau-Verwey-Overbeek (DLVO)-analyses, considering bacteria as smooth, inert colloidal particles. DLVO-analyses however, require precise indication of the bacterial cell surface, which is impossible due to the presence of bacterial surface tethers, creating a multi-scale roughness that impedes proper definition of the interaction distance in DLVO-analyses. Application of surface thermodynamics is also difficult, because initial bacterial adhesion is only an equilibrium phenomenon for a short period of time, when bacteria are attached to a substratum surface through few surface tethers. Physico-chemical bond-strengthening occurs in several minutes leading to irreversible adhesion due to progressive removal of interfacial water, conformational changes in cell surface proteins, re-orientation of bacteria on a surface and the progressive involvement of more tethers in adhesion. After initial bond-strengthening, adhesion forces arising from a substratum surface cause nanoscopic deformation of the bacterial cell wall against the elasticity of the rigid peptidoglycan layer positioned in the cell wall and the intracellular pressure of the cytoplasm. Cell wall deformation not only increases the contact area with a substratum surface, presenting another physico-chemical bond-strengthening mechanism, but is also accompanied by membrane surface tension changes. Membrane-located sensor molecules subsequently react to control emergent phenotypic and genotypic properties in biofilms, most notably adhesion-associated ones like EPS production. Moreover, also bacterial efflux pump systems may be activated or mechano-sensitive channels may be opened upon adhesion-induced cell wall deformation. The physico-chemical properties of the substratum surface thus control the response of initially adhering bacteria and through excretion of autoinducer molecules extend the awareness of their adhering state to other biofilm inhabitants who subsequently respond with similar emergent properties. Herewith, physico-chemistry is not only involved in initial bacterial adhesion to surfaces but also in what we here propose to call "surface-programmed" biofilm growth. This conclusion is pivotal for the development of new strategies to control biofilm formation on substratum surfaces, that have hitherto been largely confined to the initial bacterial adhesion phenomena.
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17
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Ren Y, Wang C, Chen Z, Allan E, van der Mei HC, Busscher HJ. Emergent heterogeneous microenvironments in biofilms: substratum surface heterogeneity and bacterial adhesion force-sensing. FEMS Microbiol Rev 2018; 42:259-272. [DOI: 10.1093/femsre/fuy001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022] Open
Affiliation(s)
- Yijin Ren
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Can Wang
- Department of Orthodontics, University of Groningen and University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
- School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, Wuhan, China
| | - Zhi Chen
- School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, Wuhan, China
| | - Elaine Allan
- UCL Eastman Dental Institute, University College London, 256 Gray's Inn Road, London WC1X 8LD, UK
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Henk J Busscher
- Department of Biomedical Engineering, University of Groningen and University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
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18
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Abstract
Mechanosensitive (MS) channels protect bacteria against hypo-osmotic shock and fulfil additional functions. Hypo-osmotic shock leads to high turgor pressure that can cause cell rupture and death. MS channels open under these conditions and release unspecifically solutes and consequently the turgor pressure. They can recognise the raised pressure via the increased tension in the cell membrane. Currently, a better understanding how MS channels can sense tension on molecular level is developing because the interaction of the lipid bilayer with the channel is being investigated in detail. The MS channel of large conductance (MscL) and of small conductance (MscS) have been distinguished and studied in molecular detail. In addition, larger channels were found that contain a homologous region corresponding to MscS so that MscS represents a family of channels. Often several members of this family are present in a species. The importance of this family is underlined by the fact that members can be found not only in bacteria but also in higher organisms. While MscL and MscS have been studied for years in particular by electrophysiology, mutagenesis, molecular dynamics, X-ray crystallography and other biophysical techniques, only recently more details are emerging about other members of the MscS-family.
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19
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Majumder S, Liu AP. Bottom-up synthetic biology: modular design for making artificial platelets. Phys Biol 2017; 15:013001. [PMID: 29091050 DOI: 10.1088/1478-3975/aa9768] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Engineering artificial cells to mimic one or multiple fundamental cell biological functions is an emerging area of synthetic biology. Reconstituting functional modules from biological components in vitro is a challenging yet an important essence of bottom-up synthetic biology. Here we describe the concept of building artificial platelets using bottom-up synthetic biology and the four functional modules that together could enable such an ambitious effort.
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Affiliation(s)
- Sagardip Majumder
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, United States of America
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20
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Aponte-Santamaría C, Brunken J, Gräter F. Stress Propagation through Biological Lipid Bilayers in Silico. J Am Chem Soc 2017; 139:13588-13591. [PMID: 28853287 DOI: 10.1021/jacs.7b04724] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Membrane tension plays various critical roles in the cell. We here asked how fast and how far localized pulses of mechanical stress dynamically propagate through biological lipid bilayers. In both coarse-grained and all-atom molecular dynamics simulations of a dipalmitoylphosphatidylcholine lipid bilayer, we observed nanometer-wide stress pulses, propagating very efficiently longitudinally at a velocity of approximately 1.4 ± 0.5 nm/ps (km/s), in close agreement with the expected speed of sound from experiments. Remarkably, the predicted characteristic attenuation time of the pulses was in the order of tens of picoseconds, implying longitudinal stress propagation over length scales up to several tens of nanometers before damping. Furthermore, the computed dispersion relation leading to such damping was consistent with proposed continuum viscoelastic models of propagation. We suggest this mode of stress propagation as a potential ultrafast mechanism of signaling that may quickly couple mechanosensitive elements in crowded biological membranes.
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Affiliation(s)
- Camilo Aponte-Santamaría
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies , 69118 Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing, Heidelberg University , 69120 Heidelberg, Germany.,Max Planck Tandem Group in Computational Biophysics, University of Los Andes , 111711 Bogotá, Colombia
| | - Jan Brunken
- Faculty of Biosciences, Heidelberg University , 69120 Heidelberg, Germany
| | - Frauke Gräter
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies , 69118 Heidelberg, Germany.,Interdisciplinary Center for Scientific Computing, Heidelberg University , 69120 Heidelberg, Germany
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21
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Martinac AD, Bavi N, Bavi O, Martinac B. Pulling MscL open via N-terminal and TM1 helices: A computational study towards engineering an MscL nanovalve. PLoS One 2017; 12:e0183822. [PMID: 28859093 PMCID: PMC5578686 DOI: 10.1371/journal.pone.0183822] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/11/2017] [Indexed: 11/18/2022] Open
Abstract
There are great opportunities in the manipulation of bacterial mechanosensitive (MS) ion channels for specific and targeted drug delivery purposes. Recent research has shown that these ion channels have the potential to be converted into nanovalves through clever use of magnetic nanoparticles and magnetic fields. Using a combination of molecular dynamics (MD) simulations and the finite element (FE) modelling, this study investigates the theoretical feasibility of opening the MscL channel (MS channel of large conductance of E. coli) by applying mechanical force directly to its N-terminus. This region has already been reported to function as a major mechanosensor in this channel. The stress-strain behaviour of each MscL helix was obtained using all atom MD simulations. Using the same method, we simulated two models, the wild-type (WT) MscL and the G22N mutant MscL, both embedded in a POPE lipid bilayer. In addition to indicating the main interacting residues at the hydrophobic pore, their pairwise interaction energies were monitored during the channel gating. We implemented these inputs into our FE model of MscL using curve-fitting codes and continuum mechanics equations. In the FE model, the channel could be fully opened via pulling directly on the N-terminus and bottom of TM1 by mutating dominant van der Waals interactions in the channel pore; otherwise the stress generated on the channel protein can irreversibly unravel the N-secondary structure. This is a significant finding suggesting that applying force in this manner is sufficient to open an MscL nanovalve delivering various drugs used, for example, in cancer chemotherapy. More importantly, the FE model indicates that to fully operate an MscL nanovalve by pulling directly on the N-terminus and bottom of TM1, gain-of-function (GOF) mutants (e.g., G22N MscL) would have to be employed rather than the WT MscL channel.
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Affiliation(s)
- Adam D. Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Navid Bavi
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW, Australia
| | - Omid Bavi
- Department of Physics, University of Tehran, Tehran, Iran
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW, Australia
- * E-mail:
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22
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Aryal P, Jarerattanachat V, Clausen MV, Schewe M, McClenaghan C, Argent L, Conrad LJ, Dong YY, Pike ACW, Carpenter EP, Baukrowitz T, Sansom MSP, Tucker SJ. Bilayer-Mediated Structural Transitions Control Mechanosensitivity of the TREK-2 K2P Channel. Structure 2017; 25:708-718.e2. [PMID: 28392258 PMCID: PMC5415359 DOI: 10.1016/j.str.2017.03.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/01/2017] [Accepted: 03/10/2017] [Indexed: 11/25/2022]
Abstract
The mechanosensitive two-pore domain (K2P) K+ channels (TREK-1, TREK-2, and TRAAK) are important for mechanical and thermal nociception. However, the mechanisms underlying their gating by membrane stretch remain controversial. Here we use molecular dynamics simulations to examine their behavior in a lipid bilayer. We show that TREK-2 moves from the “down” to “up” conformation in direct response to membrane stretch, and examine the role of the transmembrane pressure profile in this process. Furthermore, we show how state-dependent interactions with lipids affect the movement of TREK-2, and how stretch influences both the inner pore and selectivity filter. Finally, we present functional studies that demonstrate why direct pore block by lipid tails does not represent the principal mechanism of mechanogating. Overall, this study provides a dynamic structural insight into K2P channel mechanosensitivity and illustrates how the structure of a eukaryotic mechanosensitive ion channel responds to changes in forces within the bilayer. Mechanogating of TREK-2 involves movement from the down to up conformation Simulations sample a wide range of mechanosensitive K2P channel structures Changes in the pressure profile and state-dependent lipid interactions play a key role Lipid block of the inner pore does not mediate stretch activation
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Affiliation(s)
- Prafulla Aryal
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Viwan Jarerattanachat
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Michael V Clausen
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Marcus Schewe
- Department of Physiology, University of Kiel, 24118 Kiel, Germany
| | - Conor McClenaghan
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Liam Argent
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Linus J Conrad
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK
| | - Yin Y Dong
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Ashley C W Pike
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | - Elisabeth P Carpenter
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK; Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK.
| | - Stephen J Tucker
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK; OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford OX1 3PT, UK.
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23
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Melo M, Arnarez C, Sikkema H, Kumar N, Walko M, Berendsen HJC, Kocer A, Marrink SJ, Ingólfsson HI. High-Throughput Simulations Reveal Membrane-Mediated Effects of Alcohols on MscL Gating. J Am Chem Soc 2017; 139:2664-2671. [PMID: 28122455 PMCID: PMC5343553 DOI: 10.1021/jacs.6b11091] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Indexed: 12/18/2022]
Abstract
The mechanosensitive channels of large conductance (MscL) are bacterial membrane proteins that serve as last resort emergency release valves in case of severe osmotic downshock. Sensing bilayer tension, MscL channels are sensitive to changes in the bilayer environment and are, therefore, an ideal test case for exploring membrane protein coupling. Here, we use high-throughput coarse-grained molecular dynamics simulations to characterize MscL gating kinetics in different bilayer environments under the influence of alcohols. We performed over five hundred simulations to obtain sufficient statistics to reveal the subtle effects of changes in the membrane environment on MscL gating. MscL opening times were found to increase with the addition of the straight-chain alcohols ethanol, octanol, and to some extent dodecanol but not with hexadecanol. Increasing concentration of octanol increased the impeding effect, but only up to 10-20 mol %. Our in silico predictions were experimentally confirmed using reconstituted MscL in a liposomal fluorescent efflux assay. Our combined data reveal that the effect of alcohols on MscL gating arises not through specific binding sites but through a combination of the alcohol-induced changes to a number of bilayer properties and their alteration of the MscL-bilayer interface. Our work provides a key example of how extensive molecular simulations can be used to predict the functional modification of membrane proteins by subtle changes in their bilayer environment.
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Affiliation(s)
- Manuel
N. Melo
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Clément Arnarez
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Hendrik Sikkema
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Neeraj Kumar
- Groningen
Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Martin Walko
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Herman J. C. Berendsen
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Armagan Kocer
- Department
of Neuroscience, University Medical Center
Groningen, University of Groningen, Antonius Deusinglaan 1, 99713 AV, Groningen, The
Netherlands
| | - Siewert J. Marrink
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
| | - Helgi I. Ingólfsson
- Groningen
Biomolecular Science and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh
4, 9747 AG, Groningen, The Netherlands
- Biosciences
and Biotechnology Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California
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24
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Anishkin A, Sukharev S. Channel disassembled: Pick, tweak, and soak parts to soften. Channels (Austin) 2017; 11:173-175. [PMID: 28166450 DOI: 10.1080/19336950.2017.1291213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Andriy Anishkin
- a Department of Biology , University of Maryland , College Park , MD , USA
| | - Sergei Sukharev
- a Department of Biology , University of Maryland , College Park , MD , USA
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25
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26
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Bavi N, Bavi O, Vossoughi M, Naghdabadi R, Hill AP, Martinac B, Jamali Y. Nanomechanical properties of MscL α helices: A steered molecular dynamics study. Channels (Austin) 2016; 11:209-223. [PMID: 27753526 DOI: 10.1080/19336950.2016.1249077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Gating of mechanosensitive (MS) channels is driven by a hierarchical cascade of movements and deformations of transmembrane helices in response to bilayer tension. Determining the intrinsic mechanical properties of the individual transmembrane helices is therefore central to understanding the intricacies of the gating mechanism of MS channels. We used a constant-force steered molecular dynamics (SMD) approach to perform unidirectional pulling tests on all the helices of MscL in M. tuberculosis and E. coli homologs. Using this method, we could overcome the issues encountered with the commonly used constant-velocity SMD simulations, such as low mechanical stability of the helix during stretching and high dependency of the elastic properties on the pulling rate. We estimated Young's moduli of the α-helices of MscL to vary between 0.2 and 12.5 GPa with TM2 helix being the stiffest. We also studied the effect of water on the properties of the pore-lining TM1 helix. In the absence of water, this helix exhibited a much stiffer response. By monitoring the number of hydrogen bonds, it appears that water acts like a 'lubricant' (softener) during TM1 helix elongation. These data shed light on another physical aspect underlying hydrophobic gating of MS channels, in particular MscL.
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Affiliation(s)
- N Bavi
- a Division of Molecular Cardiology and Biophysics , Victor Chang Cardiac Research Institute , Darlinghurst , NSW , Australia.,b St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Darlinghurst , NSW , Australia
| | - O Bavi
- c Institute for Nanoscience and Nanotechnology, Sharif University of Technology , Tehran , Iran
| | - M Vossoughi
- c Institute for Nanoscience and Nanotechnology, Sharif University of Technology , Tehran , Iran.,d Biochemical & Bioenvironmental Research Center (BBRC) , Tehran , Iran
| | - R Naghdabadi
- c Institute for Nanoscience and Nanotechnology, Sharif University of Technology , Tehran , Iran.,e Department of Mechanical Engineering , Sharif University of Technology , Tehran , Iran
| | - A P Hill
- a Division of Molecular Cardiology and Biophysics , Victor Chang Cardiac Research Institute , Darlinghurst , NSW , Australia
| | - B Martinac
- a Division of Molecular Cardiology and Biophysics , Victor Chang Cardiac Research Institute , Darlinghurst , NSW , Australia.,b St Vincent's Clinical School, Faculty of Medicine , University of New South Wales , Darlinghurst , NSW , Australia
| | - Y Jamali
- f Department of Mathematics , Tarbiat Modares University , Tehran , Iran.,g Computational Physical Sciences Research Laboratory , School of Nanoscience, Institute for Research in Fundamental Sciences (IPM) , Tehran , Iran
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27
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Zhang XC, Liu Z, Li J. From membrane tension to channel gating: A principal energy transfer mechanism for mechanosensitive channels. Protein Sci 2016; 25:1954-1964. [PMID: 27530280 DOI: 10.1002/pro.3017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/10/2016] [Indexed: 12/17/2022]
Abstract
Mechanosensitive (MS) channels are evolutionarily conserved membrane proteins that play essential roles in multiple cellular processes, including sensing mechanical forces and regulating osmotic pressure. Bacterial MscL and MscS are two prototypes of MS channels. Numerous structural studies, in combination with biochemical and cellular data, provide valuable insights into the mechanism of energy transfer from membrane tension to gating of the channel. We discuss these data in a unified two-state model of thermodynamics. In addition, we propose a lipid diffusion-mediated mechanism to explain the adaptation phenomenon of MscS.
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Affiliation(s)
- Xuejun C Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics Chinese Academy of Sciences, CAS Center for Excellence in Biomacromolecules, Beijing, 100101, China.
| | - Zhenfeng Liu
- National Laboratory of Biomacromolecules, Institute of Biophysics Chinese Academy of Sciences, CAS Center for Excellence in Biomacromolecules, Beijing, 100101, China
| | - Jie Li
- National Laboratory of Biomacromolecules, Institute of Biophysics Chinese Academy of Sciences, CAS Center for Excellence in Biomacromolecules, Beijing, 100101, China
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28
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Danchin A, Fang G. Unknown unknowns: essential genes in quest for function. Microb Biotechnol 2016; 9:530-40. [PMID: 27435445 PMCID: PMC4993169 DOI: 10.1111/1751-7915.12384] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 06/24/2016] [Indexed: 01/18/2023] Open
Abstract
The experimental design of a minimal synthetic genome revealed the presence of a large number of genes without ascribed function, in part because the abstract laws of life must be implemented within ad hoc material contraptions. Creating a function needs recruitment of some pre‐existing structure and this reveals kludges in their set‐up and history. Here, we show that looking for functions as an engineer would help in discovery of a significant number of those, proposed together with conceptual handles allowing investigators to pursue this endeavour in other contexts.
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Affiliation(s)
- Antoine Danchin
- Institute of Cardiometabolism and Nutrition, CHU Pitié-Salpêtrière, 47 boulevard de l'Hôpital, 75013, Paris, France
| | - Gang Fang
- Department of Biology, New York University Shanghai Campus, 1555 Century Avenue, Pudong New Area, Shanghai, 200122, China
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Bavi O, Vossoughi M, Naghdabadi R, Jamali Y. The Combined Effect of Hydrophobic Mismatch and Bilayer Local Bending on the Regulation of Mechanosensitive Ion Channels. PLoS One 2016; 11:e0150578. [PMID: 26958847 PMCID: PMC4784931 DOI: 10.1371/journal.pone.0150578] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/17/2016] [Indexed: 12/03/2022] Open
Abstract
The hydrophobic mismatch between the lipid bilayer and integral membrane proteins has well-defined effect on mechanosensitive (MS) ion channels. Also, membrane local bending is suggested to modulate MS channel activity. Although a number of studies have already shown the significance of each individual factor, the combined effect of these physical factors on MS channel activity have not been investigated. Here using finite element simulation, we study the combined effect of hydrophobic mismatch and local bending on the archetypal mechanosensitive channel MscL. First we show how the local curvature direction impacts on MS channel modulation. In the case of MscL, we show inward (cytoplasmic) bending can more effectively gate the channel compared to outward bending. Then we indicate that in response to a specific local curvature, MscL inserted in a bilayer with the same hydrophobic length is more expanded in the constriction pore region compared to when there is a protein-lipid hydrophobic mismatch. Interestingly in the presence of a negative mismatch (thicker lipids), MscL constriction pore is more expanded than in the presence of positive mismatch (thinner lipids) in response to an identical membrane curvature. These results were confirmed by a parametric energetic calculation provided for MscL gating. These findings have several biophysical consequences for understanding the function of MS channels in response to two major physical stimuli in mechanobiology, namely hydrophobic mismatch and local membrane curvature.
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Affiliation(s)
- Omid Bavi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran
| | - Manouchehr Vossoughi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran
- Biochemical & Bioenvironmental Research Center (BBRC), Tehran, Iran
| | - Reza Naghdabadi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran, Iran
- Department of Mechanical Engineering, Sharif University of Technology, Tehran, Iran
| | - Yousef Jamali
- Department of Mathematics, Tarbiat Modares University, Tehran, Iran
- Computational physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
- * E-mail:
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Bavi O, Cox CD, Vossoughi M, Naghdabadi R, Jamali Y, Martinac B. Influence of Global and Local Membrane Curvature on Mechanosensitive Ion Channels: A Finite Element Approach. MEMBRANES 2016; 6:membranes6010014. [PMID: 26861405 PMCID: PMC4812420 DOI: 10.3390/membranes6010014] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 11/25/2022]
Abstract
Mechanosensitive (MS) channels are ubiquitous molecular force sensors that respond to a number of different mechanical stimuli including tensile, compressive and shear stress. MS channels are also proposed to be molecular curvature sensors gating in response to bending in their local environment. One of the main mechanisms to functionally study these channels is the patch clamp technique. However, the patch of membrane surveyed using this methodology is far from physiological. Here we use continuum mechanics to probe the question of how curvature, in a standard patch clamp experiment, at different length scales (global and local) affects a model MS channel. Firstly, to increase the accuracy of the Laplace’s equation in tension estimation in a patch membrane and to be able to more precisely describe the transient phenomena happening during patch clamping, we propose a modified Laplace’s equation. Most importantly, we unambiguously show that the global curvature of a patch, which is visible under the microscope during patch clamp experiments, is of negligible energetic consequence for activation of an MS channel in a model membrane. However, the local curvature (RL < 50) and the direction of bending are able to cause considerable changes in the stress distribution through the thickness of the membrane. Not only does local bending, in the order of physiologically relevant curvatures, cause a substantial change in the pressure profile but it also significantly modifies the stress distribution in response to force application. Understanding these stress variations in regions of high local bending is essential for a complete understanding of the effects of curvature on MS channels.
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Affiliation(s)
- Omid Bavi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Charles D Cox
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
| | - Manouchehr Vossoughi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Biochemical & Bioenvironmental Research Center (BBRC), 89694-14588 Tehran, Iran.
| | - Reza Naghdabadi
- Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 89694-14588 Tehran, Iran.
- Department of Mechanical Engineering, Sharif University of Technology, 89694-14588 Tehran, Iran.
| | - Yousef Jamali
- Department of Mathematics and Bioscience, Tarbiat Modares University, Jalal Ale Ahmad Highway, 14115-111 Tehran, Iran.
- Computational physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran, Iran.
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division/Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia.
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW 2010, Australia.
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