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Pinto-Pinho P, Soares J, Esteves P, Pinto-Leite R, Fardilha M, Colaço B. Comparative Bioinformatic Analysis of the Proteomes of Rabbit and Human Sex Chromosomes. Animals (Basel) 2024; 14:217. [PMID: 38254386 PMCID: PMC10812427 DOI: 10.3390/ani14020217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/18/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Studying proteins associated with sex chromosomes can provide insights into sex-specific proteins. Membrane proteins accessible through the cell surface may serve as excellent targets for diagnostic, therapeutic, or even technological purposes, such as sperm sexing technologies. In this context, proteins encoded by sex chromosomes have the potential to become targets for X- or Y-chromosome-bearing spermatozoa. Due to the limited availability of proteomic studies on rabbit spermatozoa and poorly annotated databases for rabbits compared to humans, a bioinformatic analysis of the available rabbit X chromosome proteome (RX), as well as the human X (HX) and Y (HY) chromosomes proteome, was conducted to identify potential targets that could be accessible from the cell surface and predict which of the potential targets identified in humans might also exist in rabbits. We identified 100, 211, and 3 proteins associated with the plasma membrane or cell surface for RX, HX, and HY, respectively, of which 61, 132, and 3 proteins exhibit potential as targets as they were predicted to be accessible from the cell surface. Cross-referencing the potential HX targets with the rabbit proteome revealed an additional 60 proteins with the potential to be RX targets, resulting in a total of 121 potential RX targets. In addition, at least 53 possible common HX and RX targets have been previously identified in human spermatozoa, emphasizing their potential as targets of X-chromosome-bearing spermatozoa. Further proteomic studies on rabbit sperm will be essential to identify and validate the usefulness of these proteins for application in rabbit sperm sorting techniques as targets of X-chromosome-bearing spermatozoa.
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Affiliation(s)
- Patrícia Pinto-Pinho
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
- Laboratory of Signal Transduction, Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal;
- Laboratory of Genetics and Andrology, Hospital Center of Trás-os-Montes and Alto Douro, E.P.E., 5000-508 Vila Real, Portugal;
- Experimental Pathology and Therapeutics Group, IPO Porto Research Center, Portuguese Institute of Oncology of Porto Francisco Gentil, E.P.E., 4200-072 Porto, Portugal
| | - João Soares
- Department of Computer Science, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal; (J.S.); (P.E.)
- Center for Research in Advanced Computing Systems, Institute for Systems and Computer Engineering, Technology and Science (CRACS—INESC TEC), 4150-179 Porto, Portugal
| | - Pedro Esteves
- Department of Computer Science, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal; (J.S.); (P.E.)
- Department of Biology, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
- CIBIO—Research Centre in Biodiversity and Genetic Resources, InBIO Associate Laboratory, 4485-661 Vairão, Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, Research Centre in Biodiversity and Genetic Resources, 4485-661 Vairão, Portugal
| | - Rosário Pinto-Leite
- Laboratory of Genetics and Andrology, Hospital Center of Trás-os-Montes and Alto Douro, E.P.E., 5000-508 Vila Real, Portugal;
- Experimental Pathology and Therapeutics Group, IPO Porto Research Center, Portuguese Institute of Oncology of Porto Francisco Gentil, E.P.E., 4200-072 Porto, Portugal
| | - Margarida Fardilha
- Laboratory of Signal Transduction, Institute of Biomedicine, Department of Medical Sciences, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Bruno Colaço
- Centre for the Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal;
- Animal and Veterinary Research Centre, University of Trás-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal
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Jiang S, He Y, Brandt JH, Zhao L, Chen J. Sensing Mechanism and Excited-State Dynamics of a Widely Used Intracellular Fluorescent pH Probe: pHrodo. J Phys Chem Lett 2023; 14:10482-10488. [PMID: 37967406 PMCID: PMC10683063 DOI: 10.1021/acs.jpclett.3c02653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/07/2023] [Accepted: 11/10/2023] [Indexed: 11/17/2023]
Abstract
The pHrodo with an "off-on" response to the changes of pH has been widely used as a fluorescent pH probe for bioimaging. The fluorescence off-on mechanism is fundamentally important for its application and further development. Herein, the sensing mechanism, especially the relevant excited-state dynamics, of pHrodo is investigated by steady-state and time-resolved spectroscopy as well as quantum chemical calculations, showing that pHrodo is best understood using the bichromophore model. Its first excited state (S1) is a charge transfer state between two chromophores. From S1, pHrodo relaxes to its ground state (S0) via an ultrafast nonradiative process (∼0.5 ps), which causes its fluorescence to be "off". After protonation, S1 becomes a localized excited state, which accounts for the fluorescence being turned "on". Our work provides photophysical insight into the sensing mechanism of pHrodo and indicates the bichromophore model might be relevant to a wide range of fluorescent probes.
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Affiliation(s)
- Simin Jiang
- Nano-Science
Center & Department of Chemistry, University
of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Yanmei He
- Nano-Science
Center & Department of Chemistry, University
of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Division
of Chemical Physics and NanoLund, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Jonas Højberg Brandt
- Nano-Science
Center & Department of Chemistry, University
of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Li Zhao
- College
of Science, China University of Petroleum
(East China), Qingdao 266580, Shandong, China
| | - Junsheng Chen
- Nano-Science
Center & Department of Chemistry, University
of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
- Division
of Chemical Physics and NanoLund, Lund University, P.O. Box 124, 22100 Lund, Sweden
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Cullinan MM, Klipp RC, Camenisch A, Bankston JR. Dynamic landscape of the intracellular termini of acid-sensing ion channel 1a. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.05.547693. [PMID: 37461628 PMCID: PMC10350031 DOI: 10.1101/2023.07.05.547693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Acid-sensing ion channels (ASICs) are trimeric proton-gated sodium channels. Recently it has been shown that these channels play a role in necroptosis following prolonged acidic exposure like occurs in stroke. The C-terminus of the channel is thought to mediate necroptotic cell death through interaction with receptor interacting serine threonine kinase 1 (RIPK1). This interaction is hypothesized to be inhibited at rest via an interaction between the C-terminus and the N-terminus which blocks the RIPK1 binding site. Here, we use a combination of two transition metal ion FRET methods to investigate the conformational dynamics of the termini while the channel is closed and desensitized. We do not find evidence that the termini are close enough to be bound while the channel is at rest and find that the termini may modestly move closer together when desensitized. At rest, the N-terminus adopts a conformation parallel to the membrane about 10 Å away. The distal end of the C-terminus may also spend time close to the membrane at rest. After acidification, the proximal portion of the N-terminus moves marginally closer to the membrane whereas the distal portion of the C-terminus swings away from the membrane. Together these data suggest that a new hypothesis for RIPK1 binding during stroke is needed.
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Affiliation(s)
- Megan M Cullinan
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Robert C Klipp
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Abigail Camenisch
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - John R Bankston
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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Tafech A, Jacquet P, Beaujean C, Fertin A, Usson Y, Stéphanou A. Characterization of the Intracellular Acidity Regulation of Brain Tumor Cells and Consequences for Therapeutic Optimization of Temozolomide. BIOLOGY 2023; 12:1221. [PMID: 37759620 PMCID: PMC10525637 DOI: 10.3390/biology12091221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/04/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023]
Abstract
A well-known feature of tumor cells is high glycolytic activity, leading to acidification of the tumor microenvironment through extensive lactate production. This acidosis promotes processes such as metastasis, aggressiveness, and invasiveness, which have been associated with a worse clinical prognosis. Moreover, the function and expression of transporters involved in regulation of intracellular pH might be altered. In this study, the capacity of tumor cells to regulate their intracellular pH when exposed to a range of pH from very acidic to basic was characterized in two glioma cell lines (F98 and U87) using a new recently published method of fluorescence imaging. Our results show that the regulation of acidity in tumors is not the same for the two investigated cell lines; U87 cells are able to reduce their intracellular acidity, whereas F98 cells do not exhibit this property. On the other hand, F98 cells show a higher level of resistance to acidity than U87 cells. Intracellular regulation of acidity appears to be highly cell-dependent, with different mechanisms activated to preserve cell integrity and function. This characterization was performed on 2D monolayer cultures and 3D spheroids. Spatial heterogeneities were exhibited in 3D, suggesting a spatially modulated regulation in this context. Based on the corpus of knowledge available in the literature, we propose plausible mechanisms to interpret our results, together with some new lines of investigation to validate our hypotheses. Our results might have implications on therapy, since the activity of temozolomide is highly pH-dependent. We show that the drug efficiency can be enhanced, depending on the cell type, by manipulating the extracellular pH. Therefore, personalized treatment involving a combination of temozolomide and pH-regulating agents can be considered.
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Affiliation(s)
| | | | | | | | | | - Angélique Stéphanou
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France; (A.T.); (P.J.); (C.B.); (A.F.); (Y.U.)
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Onufriev AV. Biologically relevant small variations of intra-cellular pH can have significant effect on stability of protein-DNA complexes, including the nucleosome. Front Mol Biosci 2023; 10:1067787. [PMID: 37143824 PMCID: PMC10151541 DOI: 10.3389/fmolb.2023.1067787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/16/2023] [Indexed: 05/06/2023] Open
Abstract
Stability of a protein-ligand complex may be sensitive to pH of its environment. Here we explore, computationally, stability of a set of protein-nucleic acid complexes using fundamental thermodynamic linkage relationship. The nucleosome, as well as an essentially random selection of 20 protein complexes with DNA or RNA, are included in the analysis. An increase in intra-cellular/intra-nuclear pH destabilizes most complexes, including the nucleosome. We propose to quantify the effect by ΔΔG0.3-the change in the binding free energy due to pH increase of 0.3 units, corresponding to doubling of the H + activity; variations of pH of this amplitude can occur in living cells, including in the course of the cell cycle, and in cancer cells relative to normal ones. We suggest, based on relevant experimental findings, a threshold of biological significance of 1 2 k B T ( ∼ 0.3 k c a l / m o l ) for changes of stability of chromatin-related protein-DNA complexes: a change in the binding affinity above the threshold may have biological consequences. We find that for 70% of the examined complexes, Δ Δ G 0.3 > 1 2 k B T (for 10%, ΔΔG0.3 is between 3 and 4 k B T). Thus, small but relevant variations of intra-nuclear pH of 0.3 may have biological consequences for many protein-nucleic acid complexes. The binding affinity between the histone octamer and its DNA, which directly affects the DNA accessibility in the nucleosome, is predicted to be highly sensitive to intra-nuclear pH. A variation of 0.3 units results in ΔΔG0.3 ∼ 10k B T ( ∼ 6 k c a l / m o l ) ; for spontaneous unwrapping of 20 bp long entry/exit fragments of the nucleosomal DNA, ΔΔG0.3 = 2.2k B T; partial disassembly of the nucleosome into the tetrasome is characterized by ΔΔG0.3 = 5.2k B T. The predicted pH -induced modulations of the nucleosome stability are significant enough to suggest that they may have consequences relevant to the biological function of the nucleosome. Accessibility of the nucleosomal DNA is predicted to positively correlate with pH variations during the cell cycle; an increase in intra-cellular pH seen in cancer cells is predicted to lead to a more accessible nucleosomal DNA; a drop in pH associated with apoptosis is predicted to make nucleosomal DNA less accessible. We speculate that processes that depend on accessibility to the DNA in the nucleosomes, such as transcription or DNA replication, might become upregulated due to relatively small, but nevertheless realistic increases of intra-nuclear pH.
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Affiliation(s)
- Alexey V. Onufriev
- Department of Physics, Virginia Tech, Blacksburg, Blacksburg, VA, United States
- Department of Computer Science, Virginia Tech, Blacksburg, Blacksburg, VA, United States
- Center from Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA, United States
- *Correspondence: Alexey V. Onufriev,
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Poet M, Doyen D, Van Obberghen E, Jarretou G, Bouret Y, Counillon L. How Does Our Knowledge on the Na+/H+ Exchanger NHE1 Obtained by Biochemical and Molecular Analyses Keep up With Its Recent Structure Determination? Front Physiol 2022; 13:907587. [PMID: 35910559 PMCID: PMC9334524 DOI: 10.3389/fphys.2022.907587] [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: 03/29/2022] [Accepted: 06/06/2022] [Indexed: 11/23/2022] Open
Abstract
Na+/H+ exchangers are membrane transporters conserved in all living systems and therefore are assumed to be amongst the most ancestral molecular devices that equipped the first protocells. Following the cloning and sequencing of its gene, the mammalian NHE1, that regulates pH and volume in all cells, has been thoroughly scrutinized by molecular and biochemical analyses. Those gave a series of crucial clues concerning its topology, dimeric organization, pharmacological profile, regulation, and the role of key amino acids. Recently thanks to cryogenic Electron Microscopy (Cryo-EM) the long-awaited molecular structures have been revealed. With this information in mind we will challenge the robustness of the earlier conclusions and highlight how the new information enriches our understanding of this key cellular player. At the mechanistic level, we will pinpoint how the NHE1 3D structures reveal that the previously identified amino acids and regions are organized to coordinate transported cations, and shape the allosteric transition that makes NHE1 able to sense intracellular pH and be regulated by signaling pathways.
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Affiliation(s)
- Mallorie Poet
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - Denis Doyen
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- Centre Hospitalier Universitaire de Nice, Nice, France
| | - Emmanuel Van Obberghen
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- Centre Hospitalier Universitaire de Nice, Nice, France
| | - Gisèle Jarretou
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - Yann Bouret
- Université Côte d’Azur, CNRS, Institut de Physique de Nice (INPHYNI), Valbonne, France
| | - Laurent Counillon
- Université Côte d’Azur, CNRS, Laboratoire de PhysioMédecine Moléculaire (LP2M), Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
- *Correspondence: Laurent Counillon,
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Dotsenko OI. The whole-cell kinetic metabolic model of the pH regulation mechanisms in human erythrocytes. REGULATORY MECHANISMS IN BIOSYSTEMS 2022. [DOI: 10.15421/022235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mathematical modeling in recent years helped to obtain answers to questions that were difficult or even impossible to answer experimentally, to predict several unexpected connections in cell metabolism and to understand and importance of certain biochemical reactions. Due to the complexity and variety of processes underlying the mechanisms of intracellular pH (pHi) regulation, mathematical modeling and metabolome analysis are powerful tools for their analysis. In this regard, a mathematical metabolic model for human erythrocytes was created, which combines cellular metabolism with acid-base processes and gas exchange. The model consists of the main metabolic pathways, such as glycolysis, the pentose phosphate pathway, some membrane transport systems, and interactions between hemoglobin and metabolites. The Jacobs-Stewart cycle, which is fundamental in gas exchange and pH regulation, was included to these pathways. The model was created in the COPASI environment, consisted of 85 reactions, the rate of which is based on accurate kinetic equations. The time dependences of reaction flows and metabolite concentrations, as an outcome of calculations, allowed us to reproduce the behaviour of the metabolic system after its disturbance in vitro and to establish the recovery mechanisms or approximation to stationary states. The COPASI simulation environment provides model flexibility by reproducing any experimental design by optimizing direct quantitative comparisons between measured and predicted results. Thus, the procedure of parameters optimization (Parameter Estimation) followed by the solution of the model’s differential equations (Time Course procedure) was used to predict the behaviour of all measured and unmeasured variables over time. The initial intracellular concentrations of CO2, HCO3– in human erythrocytes used for incubation in a phosphate buffer medium were calculated. Changes in CO2, HCO3– content over time were shown. It was established that the regulation of pH in erythrocytes placed in a buffer medium takes place with the participation of two types of processes – fast (takes place in 1.3 s) and slow. It is shown that fast processes are aimed at restoring the intracellular balance between CO2 and HCO3–, slow processes are aimed at establishing the balance of H+ between the cell and the extracellular environment. The role of carbonic anhydrase (CA) and hemoglobin in the processes of pH stabilization is shown and analyzed. The physiological role of the metabolon between band 3 protein (AE1), CA, aquaporin and hemoglobin in maintaining pH homeostasis in the conditions of in vitro experiments are discussed.
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