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Bukhteeva I, Rahman FA, Kendall B, Duncan RE, Quadrilatero J, Pavlov EV, Gingras MJP, Leonenko Z. Effects of lithium isotopes on sodium/lithium co-transport and calcium efflux through the sodium/calcium/lithium exchanger in mitochondria. Front Physiol 2024; 15:1354091. [PMID: 38655027 PMCID: PMC11036541 DOI: 10.3389/fphys.2024.1354091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/06/2024] [Indexed: 04/26/2024] Open
Abstract
The effects of lithium (Li) isotopes and their impact on biological processes have recently gained increased attention due to the significance of Li as a pharmacological agent and the potential that Li isotopic effects in neuroscience contexts may constitute a new example of quantum effects in biology. Previous studies have shown that the two Li isotopes, which differ in mass and nuclear spin, have unusual different effects in vivo and in vitro and, although some molecular targets for Li isotope fractionation have been proposed, it is not known whether those result in observable downstream neurophysiological effects. In this work we studied fluxes of Li+, sodium (Na+) and calcium (Ca2+) ions in the mitochondrial sodium/calcium/lithium exchanger (NCLX), the only transporter known with recognized specificity for Li+. We studied the effect of Li+ isotopes on Ca2+ efflux from heart mitochondria in comparison to natural Li+ and Na+ using Ca2+-induced fluorescence and investigated a possible Li isotope fractionation in mitochondria using inductively coupled plasma mass spectrometry (ICP-MS). Our fluorescence data indicate that Ca2+ efflux increases with higher concentrations of either Li+ or Na+. We found that the simultaneous presence of Li+ and Na+ increases Ca2+ efflux compared to Ca2+ efflux caused by the same concentration of Li+ alone. However, no differentiation in the Ca2+ efflux between the two Li+ isotopes was observed, either for Li+ alone or in mixtures of Li+ and Na+. Our ICP-MS data demonstrate that there is selectivity between Na+ and Li+ (greater Na+ than Li+ uptake) and, most interestingly, between the Li+ isotopes (greater 6Li+ than 7Li+ uptake) by the inner mitochondrial membrane. In summary, we observed no Li+ isotope differentiation for Ca2+ efflux in mitochondria via NCLX but found a Li+ isotope fractionation during Li+ uptake by mitochondria with NCLX active or blocked. Our results suggest that the transport of Li+ via NCLX is not the main pathway for Li+ isotope fractionation and that this differentiation does not affect Ca2+ efflux in mitochondria. Therefore, explaining the puzzling effects of Li+ isotopes observed in other contexts will require further investigation to identify the molecular targets for Li+ isotope differentiation.
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Affiliation(s)
- Irina Bukhteeva
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Fasih A. Rahman
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Brian Kendall
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Robin E. Duncan
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Joe Quadrilatero
- Department of Kinesiology & Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Evgeny V. Pavlov
- Department of Molecular Pathobiology, New York University, New York, NY, United States
| | - Michel J. P. Gingras
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada
| | - Zoya Leonenko
- Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, Canada
- Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, Canada
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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Bukhteeva I, Hrunyk NI, Yusypovych YM, Shalovylo YI, Kovaleva V, Nesmelova IV. Structure, dynamics, and function of PsDef2 defensin from Pinus sylvestris. Structure 2022; 30:753-762.e5. [PMID: 35334207 DOI: 10.1016/j.str.2022.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/25/2022] [Accepted: 02/28/2022] [Indexed: 11/19/2022]
Abstract
Plant defensins demonstrate high structural stability at extreme temperatures and pH values and, in general, are non-toxic to mammalian cells. These properties make them attractive candidates for use in biotechnology and biomedicine. Knowing the structure-function relationship is desirable to guide the design of plant defensin-based applications. Thus far, the broad range of biological activities was described only for one defensin from gymnosperms, the defensin PsDef1 from Scots pine. Here, we report that closely related defensin from the same taxonomy group, PsDef2, differing from PsDef1 by six amino acids, also possesses antimicrobial, antibacterial, and insect α-amylase inhibitory activities. We also report the solution structure and dynamics properties of PsDef2 assessed using a combination of experimental nuclear magnetic resonance (NMR) techniques. Lastly, we perform a comparative analysis of PsDef2 and PsDef1 gaining a molecular-level insight into their structure-dynamics-function relationship.
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Affiliation(s)
- Irina Bukhteeva
- Department of Physics and Optical Science, University of North Carolina, Charlotte, NC 28223, USA
| | - Natalia I Hrunyk
- The Laboratory of Molecular Genetic Markers in Plants, Ukrainian National Forestry University, Lviv 79057, Ukraine
| | - Yuri M Yusypovych
- The Laboratory of Molecular Genetic Markers in Plants, Ukrainian National Forestry University, Lviv 79057, Ukraine
| | - Yulia I Shalovylo
- The Laboratory of Molecular Genetic Markers in Plants, Ukrainian National Forestry University, Lviv 79057, Ukraine
| | - Valentina Kovaleva
- The Laboratory of Molecular Genetic Markers in Plants, Ukrainian National Forestry University, Lviv 79057, Ukraine
| | - Irina V Nesmelova
- Department of Physics and Optical Science, University of North Carolina, Charlotte, NC 28223, USA.
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