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Ramsey K, Britt M, Maramba J, Ushijima B, Moller E, Anishkin A, Häse C, Sukharev S. The dynamic hypoosmotic response of Vibrio cholerae relies on the mechanosensitive channel MscS. iScience 2024; 27:110001. [PMID: 38868203 PMCID: PMC11167432 DOI: 10.1016/j.isci.2024.110001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 03/04/2024] [Accepted: 05/14/2024] [Indexed: 06/14/2024] Open
Abstract
Vibrio cholerae adapts to osmotic down-shifts by releasing metabolites through two mechanosensitive (MS) channels, low-threshold MscS and high-threshold MscL. To investigate each channel's contribution to the osmotic response, we generated ΔmscS, ΔmscL, and double ΔmscL ΔmscS mutants in V. cholerae O395. We characterized their tension-dependent activation in patch-clamp, and the millisecond-scale osmolyte release kinetics using a stopped-flow light scattering technique. We additionally generated numerical models describing osmolyte and water fluxes. We illustrate the sequence of events and define the parameters that characterize discrete phases of the osmotic response. Survival is correlated to the extent of cell swelling, the rate of osmolyte release, and the completeness of post-shock membrane resealing. Not only do the two channels interact functionally, but there is also an up-regulation of MscS in the ΔmscL strain, suggesting transcriptional crosstalk. The data reveal the role of MscS in the termination of the osmotic permeability response in V. cholerae.
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Affiliation(s)
- Kristen Ramsey
- Department of Biology, University of Maryland, College Park, MD, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA
| | - Madolyn Britt
- Department of Biology, University of Maryland, College Park, MD, USA
- Biophysics Graduate Program, University of Maryland, College Park, MD, USA
| | - Joseph Maramba
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Blake Ushijima
- Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, USA
| | - Elissa Moller
- Department of Biology, University of Maryland, College Park, MD, USA
- Biophysics Graduate Program, University of Maryland, College Park, MD, USA
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD, USA
| | - Claudia Häse
- Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, MD, USA
- Biophysics Graduate Program, University of Maryland, College Park, MD, USA
- Institute for Physical Science and Technology, University of Maryland, College Park, MD, USA
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Chilamakuru NB, Vn AD, G VB, Pallaprolu N, Dande A, Nair D, Pemmadi RV, Reddy Y P, Peraman R. New synergistic benzoquinone scaffolds as inhibitors of mycobacterial cytochrome bc1 complex to treat multi-drug resistant tuberculosis. Eur J Med Chem 2024; 272:116479. [PMID: 38733886 DOI: 10.1016/j.ejmech.2024.116479] [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: 03/18/2024] [Revised: 04/25/2024] [Accepted: 05/04/2024] [Indexed: 05/13/2024]
Abstract
Through a comprehensive molecular docking study, a unique series of naphthoquinones clubbed azetidinone scaffolds was arrived with promising binding affinity to Mycobacterial Cytbc1 complex, a drug target chosen to kill multi-drug resistant Mycobacterium tuberculosis (MDR-Mtb). Five compounds from series-2, 2a, 2c, 2g, 2h, and 2j, showcased significant in vitro anti-tubercular activities against Mtb H37Rv and MDR clinical isolates. Further, synergistic studies of these compounds in combination with INH and RIF revealed a potent bactericidal effect of compound 2a at concentration of 0.39 μg/mL, and remaining (2c, 2g, 2h, and 2j) at 0.78 μg/mL. Exploration into the mechanism study through chemo-stress assay and proteome profiling uncovered the down-regulation of key proteins of electron-transport chain and Cytbc1 inhibition pathway. Metabolomics corroborated these proteome findings, and heightened further understanding of the underlying mechanism. Notably, in vitro and in vivo animal toxicity studies demonstrated minimal toxicity, thus underscoring the potential of these compounds as promising anti-TB agents in combination with RIF and INH. These active compounds adhered to Lipinski's Rule of Five, indicating the suitability of these compounds for drug development. Particular significance of molecules NQ02, 2a, and 2h, which have been patented (Published 202141033473).
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Affiliation(s)
- Naresh Babu Chilamakuru
- Research Scholar, Manipal Academy of Higher Education, Manipal, 576104, Karnataka, India; RERDS-CPR, Raghavendra Institute of Pharmaceutical Education and Research Campus, Ananthapuramu, 515721, Andhra Pradesh, India
| | - Azger Dusthackeer Vn
- ICMR-National Institute for Research in Tuberculosis (NIRT), Chennai, 600031, Tamil Nadu, India
| | - Varadaraj Bhat G
- Department of Pharmaceutical Chemistry, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, Karnataka, India
| | - Nikhil Pallaprolu
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hajipur 844102, Bihar, India
| | - Aishwarya Dande
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hajipur 844102, Bihar, India
| | - Dina Nair
- ICMR-National Institute for Research in Tuberculosis (NIRT), Chennai, 600031, Tamil Nadu, India
| | - Raghuveer Varma Pemmadi
- RERDS-CPR, Raghavendra Institute of Pharmaceutical Education and Research Campus, Ananthapuramu, 515721, Andhra Pradesh, India; Department of Pharmaceutical Chemistry, A.K.R.G College of Pharmacy, Nallajerla, Andhra Pradesh 534112.
| | - Padmanabha Reddy Y
- RERDS-CPR, Raghavendra Institute of Pharmaceutical Education and Research Campus, Ananthapuramu, 515721, Andhra Pradesh, India
| | - Ramalingam Peraman
- RERDS-CPR, Raghavendra Institute of Pharmaceutical Education and Research Campus, Ananthapuramu, 515721, Andhra Pradesh, India; Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hajipur 844102, Bihar, India.
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Wan J, Dai L, Xiao H, Zhang W, Zhang R, Xie T, Jia Y, Gao X, Huang J, Liu F. Biological characteristics of mechanosensitive channels MscS and MscL in Actinobacillus pleuropneumoniae. J Bacteriol 2024; 206:e0042923. [PMID: 38391161 PMCID: PMC10955882 DOI: 10.1128/jb.00429-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 01/29/2024] [Indexed: 02/24/2024] Open
Abstract
Actinobacillus pleuropneumoniae is an important respiratory pathogen that can cause porcine contagious pleuropneumonia (PCP), resulting in significant economic losses in swine industry. Microorganisms are subjected to drastic changes in environmental osmolarity. In order to alleviate the drastic rise or fall of osmolarity, cells activate mechanosensitive channels MscL and MscS through tension changes. MscL not only regulates osmotic pressure but also has been reported to secrete protein and uptake aminoglycoside antibiotic. However, MscL and MscS, as the most common mechanosensitive channels, have not been characterized in A. pleuropneumoniae. In this study, the osmotic shock assay showed that MscL increased sodium adaptation by regulating cell length. The results of MIC showed that deletion of mscL decreased the sensitivity of A. pleuropneumoniae to multiple antibiotics, while deletion of mscS rendered A. pleuropneumoniae hypersensitive to penicillin. Biofilm assay demonstrated that MscL contributed the biofilm formation but MscS did not. The results of animal assay showed that MscL and MscS did not affect virulence in vivo. In conclusion, MscL is essential for sodium hyperosmotic tolerance, biofilm formation, and resistance to chloramphenicol, erythromycin, penicillin, and oxacillin. On the other hand, MscS is only involved in oxacillin resistance.IMPORTANCEBacterial resistance to the external environment is a critical function that ensures the normal growth of bacteria. MscL and MscS play crucial roles in responding to changes in both external and internal environments. However, the function of MscL and MscS in Actinobacillus pleuropneumoniae has not yet been reported. Our study shows that MscL plays a significant role in osmotic adaptation, antibiotic resistance, and biofilm formation of A. pleuropneumoniae, while MscS only plays a role in antibiotic resistance. Our findings provide new insights into the functional characteristics of MscL and MscS in A. pleuropneumoniae. MscL and MscS play a role in antibiotic resistance and contribute to the development of antibiotics for A. pleuropneumoniae.
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Affiliation(s)
- Jiajia Wan
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Lu Dai
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Huasong Xiao
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Wendie Zhang
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Rui Zhang
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Tingting Xie
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Yizhen Jia
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Xuejun Gao
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
| | - Jing Huang
- College of Arts and Sciences, Yangtze University, Jingzhou, Hubei, China
| | - Feng Liu
- College of Animal Science and Technology, Yangtze University, Jingzhou, Hubei, China
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Britt M, Moller E, Maramba J, Anishkin A, Sukharev S. MscS inactivation and recovery are slow voltage-dependent processes sensitive to interactions with lipids. Biophys J 2024; 123:195-209. [PMID: 38098232 PMCID: PMC10808034 DOI: 10.1016/j.bpj.2023.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/28/2023] [Accepted: 12/07/2023] [Indexed: 12/26/2023] Open
Abstract
Mechanosensitive channel MscS, the major bacterial osmolyte release valve, shows a characteristic adaptive behavior. With a sharp onset of activating tension the channel population readily opens, but under prolonged action of moderate tension it inactivates. The inactivated state is non-conductive and tension insensitive, which suggests that the gate becomes uncoupled from the lipid-facing domains. Because the distinct opening and inactivation transitions are both driven from the closed state by tension transmitted through the lipid bilayer, here we explore how mutations of two conserved positively charged lipid anchors, R46 and R74, affect 1) the rates of opening and inactivation and 2) the voltage dependences of these transitions. Previously estimated kinetic rates for opening-closing transitions in wild-type MscS at low voltages were 3-6 orders of magnitude higher than the rates for inactivation and recovery. Here we show that MscS activation exhibits a shallow nearly symmetric dependence on voltage, whereas inactivation is substantially augmented and recovery is slowed down by depolarization. Conversely, hyperpolarization impedes inactivation and speeds up recovery. Mutations of R46 and R74 anchoring the lipid-facing helices to the inner interface to an aromatic residue (W) do not substantially change the activation energy and closing rates, but instead change the kinetics of both inactivation and recovery and essentially eliminate their voltage dependence. Uncharged polar substitutions (S or Q) for these anchors produce functional channels but increase the inactivation and reduce the recovery rates. The data clearly delineate the activation-closing and the inactivation-recovery pathways and strongly suggest that only the latter involves extensive rearrangements of the protein-lipid boundary associated with the uncoupling of the lipid-facing helices from the gate. The discovery that hyperpolarization robustly assists MscS recovery suggests that membrane potential is one of the factors that regulates osmolyte release valves by putting them either on "ready" or "standby" based on the cell's metabolic state.
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Affiliation(s)
- Madolyn Britt
- Department of Biology, University of Maryland, College Park, Maryland; Maryland Biophysics Program, University of Maryland, College Park, Maryland
| | - Elissa Moller
- Department of Biology, University of Maryland, College Park, Maryland; Maryland Biophysics Program, University of Maryland, College Park, Maryland
| | - Joseph Maramba
- Department of Biology, University of Maryland, College Park, Maryland
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, Maryland; Instiute for Physical Science and Technology, University of Maryland, College Park, Maryland; Maryland Biophysics Program, University of Maryland, College Park, Maryland.
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Ramsey K, Britt M, Maramba J, Ushijima B, Moller E, Anishkin A, Hase C, Sukharev S. The dynamic hypoosmotic response of Vibrio cholerae relies on the mechanosensitive channel MscS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539864. [PMID: 37214804 PMCID: PMC10197554 DOI: 10.1101/2023.05.08.539864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Like other intestinal bacteria, the facultative pathogen Vibrio cholerae adapts to a wide range of osmotic environments. Under drastic osmotic down-shifts, Vibrio avoids mechanical rupture by rapidly releasing excessive metabolites through mechanosensitive (MS) channels that belong to two major types, low-threshold MscS and high-threshold MscL. To investigate each channel individual contribution to V. cholerae osmotic permeability response, we generated individual ΔmscS, ∆mscL, and double ΔmscL ΔmscS mutants in V. cholerae O395 and characterized their tension-dependent activation in patch-clamp experiments, as well as their millisecond-scale osmolyte release kinetics using a stopped-flow light scattering technique. We additionally generated numerical models reflecting the kinetic competition of osmolyte release with water influx. Both mutants lacking MscS exhibited delayed osmolyte release kinetics and decreased osmotic survival rates compared to WT. The ΔmscL mutant showed comparable release kinetics to WT, but a higher osmotic survival, while ΔmscS had low survival, comparable to the double ΔmscL ΔmscS mutant. By analyzing release kinetics following rapid medium dilution, we illustrate the sequence of events and define the set of parameters that characterize discrete phases of the osmotic response. Osmotic survival rates are directly correlated to the extent and duration of cell swelling, the rate of osmolyte release and the onset time, and the completeness of the post-shock membrane resealing. Not only do the two channels interact functionally during the resealing phase, but there is also a compensatory up-regulation of MscS in the ΔmscL strain suggesting some transcriptional crosstalk. The data reveal the advantage of the low-threshold MscS channel in curbing tension surges, without which MscL becomes toxic, and the role of MscS in the proper termination of the osmotic permeability response in Vibrio.
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Çetiner U, Raz O, Britt M, Sukharev S. Dissipation during the Gating Cycle of the Bacterial Mechanosensitive Ion Channel Approaches the Landauer Limit. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25050779. [PMID: 37238534 DOI: 10.3390/e25050779] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/03/2023] [Accepted: 05/03/2023] [Indexed: 05/28/2023]
Abstract
The Landauer principle sets a thermodynamic bound of kBT ln 2 on the energetic cost of erasing each bit of information. It holds for any memory device, regardless of its physical implementation. It was recently shown that carefully built artificial devices can attain this bound. In contrast, biological computation-like processes, e.g., DNA replication, transcription and translation use an order of magnitude more than their Landauer minimum. Here, we show that reaching the Landauer bound is nevertheless possible with biological devices. This is achieved using a mechanosensitive channel of small conductance (MscS) from E. coli as a memory bit. MscS is a fast-acting osmolyte release valve adjusting turgor pressure inside the cell. Our patch-clamp experiments and data analysis demonstrate that under a slow switching regime, the heat dissipation in the course of tension-driven gating transitions in MscS closely approaches its Landauer limit. We discuss the biological implications of this physical trait.
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Affiliation(s)
- Uğur Çetiner
- Maryland Biophysics Program, Institute for Physical Science and Technology, Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Oren Raz
- Department of Physics of Complex Systems, Faculty of Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Madolyn Britt
- Maryland Biophysics Program, Institute for Physical Science and Technology, Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Sergei Sukharev
- Maryland Biophysics Program, Institute for Physical Science and Technology, Department of Biology, University of Maryland, College Park, MD 20742, USA
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