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Frustaci A, Letizia C, Chimenti C, Verardo R, Alfarano M, Scialla R, Bagnato G, Miraldi F, Sansone L, Russo MA. Myocardial Aldosterone Receptor and Aquaporin 1 Up-Regulation Is Associated with Cardiomyocyte Remodeling in Human Heart Failure. J Clin Med 2021; 10:4854. [PMID: 34768373 PMCID: PMC8585058 DOI: 10.3390/jcm10214854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/06/2021] [Accepted: 10/19/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Abnormal aldosterone signaling is a recognized source of cardiovascular damage. Its influence on cardiomyocyte structure, function, and hormonal receptors when associated with heart failure is still unreported. METHODS Twenty-six consecutive patients with heart failure (LVEF < 40%) and normal coronaries and valves underwent left ventricular endomyocardial biopsy (EMB) for evaluation of myocardial substrate. Biopsy samples were processed for histology, electron microscopy, immunohistochemistry, and Western blot analysis of myocardial aldosterone receptor and aquaporin-1 correlated with plasma aldosterone (AD) and renin activity (PRA). Eight patients with virus-negative inflammatory cardiomyopathy (ICM) had a control EMB after 6 months of immunosuppressive therapy and recovery of cardiac function with re-evaluation of cardiomyocyte structure and receptor expression. RESULTS EMB in addition to the diagnosis of myocarditis (15 cases), dilated cardiomyopathy CM (6), alcohol CM (2), and diabetic CM (3) showed vacuolar degeneration and cloudy swelling of cardiomyocytes corresponding at electron microscopy to ions and water accumulation into cytosol, membrane-bound vesicles, nucleus, and other organelles, and was associated with an increased AD, PRA, and myocardial expression of aldosterone receptor (2.6 fold) and aquaporin 1 (2.7 fold). In the 8 patients recovered from ICM, cardiomyocyte diameter reduced with disappearance of intracellular vacuoles and normalization of cytosol, nucleus, and cell organelles' electron-density, along with down-regulation of aldosterone receptor and aquaporin-1. CONCLUSION Human heart failure is associated with overexpression of myocardial aldosterone receptor and aquaporin-1. These molecular changes are paralleled by intracellular water overloading and cardiomyocyte swelling and dysfunction. Cardiac recovery is accompanied by down-regulation of hormonal receptors and normalization of cell structure and composition.
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Affiliation(s)
- Andrea Frustaci
- Department of Clinical, Internal, Anesthesiologist and Cardiovascular Sciences, Sapienza University, 00161 Rome, Italy; (C.C.); (M.A.); (F.M.)
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, 00149 Rome, Italy; (R.V.); (R.S.); (G.B.)
| | - Claudio Letizia
- Department of Translation Medicine and Precision, Sapienza University, 00161 Rome, Italy;
| | - Cristina Chimenti
- Department of Clinical, Internal, Anesthesiologist and Cardiovascular Sciences, Sapienza University, 00161 Rome, Italy; (C.C.); (M.A.); (F.M.)
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, 00149 Rome, Italy; (R.V.); (R.S.); (G.B.)
| | - Romina Verardo
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, 00149 Rome, Italy; (R.V.); (R.S.); (G.B.)
| | - Maria Alfarano
- Department of Clinical, Internal, Anesthesiologist and Cardiovascular Sciences, Sapienza University, 00161 Rome, Italy; (C.C.); (M.A.); (F.M.)
| | - Rossella Scialla
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, 00149 Rome, Italy; (R.V.); (R.S.); (G.B.)
| | - Giulia Bagnato
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, 00149 Rome, Italy; (R.V.); (R.S.); (G.B.)
| | - Fabio Miraldi
- Department of Clinical, Internal, Anesthesiologist and Cardiovascular Sciences, Sapienza University, 00161 Rome, Italy; (C.C.); (M.A.); (F.M.)
| | - Luigi Sansone
- Laboratory of Molecular and Cellular Pathology, IRCCS San Raffaele Pisana, 00163 Rome, Italy;
| | - Matteo Antonio Russo
- MEBIC Consortium, San Raffaele Open University, 00163 Rome, Italy;
- IRCCS San Raffaele Pisana, 00163 Rome, Italy
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Ritter M, Bresgen N, Kerschbaum HH. From Pinocytosis to Methuosis-Fluid Consumption as a Risk Factor for Cell Death. Front Cell Dev Biol 2021; 9:651982. [PMID: 34249909 PMCID: PMC8261248 DOI: 10.3389/fcell.2021.651982] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
The volumes of a cell [cell volume (CV)] and its organelles are adjusted by osmoregulatory processes. During pinocytosis, extracellular fluid volume equivalent to its CV is incorporated within an hour and membrane area equivalent to the cell's surface within 30 min. Since neither fluid uptake nor membrane consumption leads to swelling or shrinkage, cells must be equipped with potent volume regulatory mechanisms. Normally, cells respond to outwardly or inwardly directed osmotic gradients by a volume decrease and increase, respectively, i.e., they shrink or swell but then try to recover their CV. However, when a cell death (CD) pathway is triggered, CV persistently decreases in isotonic conditions in apoptosis and it increases in necrosis. One type of CD associated with cell swelling is due to a dysfunctional pinocytosis. Methuosis, a non-apoptotic CD phenotype, occurs when cells accumulate too much fluid by macropinocytosis. In contrast to functional pinocytosis, in methuosis, macropinosomes neither recycle nor fuse with lysosomes but with each other to form giant vacuoles, which finally cause rupture of the plasma membrane (PM). Understanding methuosis longs for the understanding of the ionic mechanisms of cell volume regulation (CVR) and vesicular volume regulation (VVR). In nascent macropinosomes, ion channels and transporters are derived from the PM. Along trafficking from the PM to the perinuclear area, the equipment of channels and transporters of the vesicle membrane changes by retrieval, addition, and recycling from and back to the PM, causing profound changes in vesicular ion concentrations, acidification, and-most importantly-shrinkage of the macropinosome, which is indispensable for its proper targeting and cargo processing. In this review, we discuss ion and water transport mechanisms with respect to CVR and VVR and with special emphasis on pinocytosis and methuosis. We describe various aspects of the complex mutual interplay between extracellular and intracellular ions and ion gradients, the PM and vesicular membrane, phosphoinositides, monomeric G proteins and their targets, as well as the submembranous cytoskeleton. Our aim is to highlight important cellular mechanisms, components, and processes that may lead to methuotic CD upon their derangement.
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Affiliation(s)
- Markus Ritter
- Center for Physiology, Pathophysiology and Biophysics, Institute for Physiology and Pathophysiology, Paracelsus Medical University, Salzburg, Austria
- Institute for Physiology and Pathophysiology, Paracelsus Medical University, Nuremberg, Germany
- Gastein Research Institute, Paracelsus Medical University, Salzburg, Austria
- Ludwig Boltzmann Institute for Arthritis und Rehabilitation, Salzburg, Austria
- Kathmandu University School of Medical Sciences, Dhulikhel, Nepal
| | - Nikolaus Bresgen
- Department of Biosciences, University of Salzburg, Salzburg, Austria
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Gheorghiu M, Stănică L, Ghinia Tegla MG, Polonschii C, Bratu D, Popescu O, Badea T, Gheorghiu E. Cellular sensing platform with enhanced sensitivity based on optogenetic modulation of cell homeostasis. Biosens Bioelectron 2020; 154:112003. [PMID: 32056953 PMCID: PMC7685521 DOI: 10.1016/j.bios.2019.112003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/26/2019] [Accepted: 12/28/2019] [Indexed: 12/29/2022]
Abstract
We demonstrate a new biosensing concept with impact on the development of rapid, point of need cell based sensing with boosted sensitivity and wide relevance for bioanalysis. It involves optogenetic stimulation of cells stably transfected to express light sensitive protein channels for optical control of membrane potential and of ion homeostasis. Time-lapse impedance measurements are used to reveal cell dynamics changes encompassing cellular responses to bioactive stimuli and optically induced homeostasis disturbances. We prove that light driven perturbations of cell membrane potential induce homeostatic reactions and modulate transduction mechanisms that amplify cellular response to bioactive compounds. This allows cell based biosensors to respond more rapidly and sensitively to low concentrations of bioactive/toxic analytes: statistically relevant impedance changes are recorded in less than 30 min, in comparison with >8 h in the best alternative reported tests for the same low concentration (e.g. a concentration of 25 μM CdCl2, lower than the threshold concentration in classical cellular sensors). Comparative analysis of model bioactive/toxic compounds (ouabain and CdCl2) demonstrates that cellular reactivity can be boosted by light driven perturbations of cellular homeostasis and that this biosensing concept is able to discriminate analytes with different modes of action (i.e. CdCl2 toxicity versus ion pump inhibition by ouabain), a significant advance against state of the art cell based sensors.
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Affiliation(s)
- Mihaela Gheorghiu
- International Centre of Biodynamics, Intr. Portocalelor 1 B, 060101, Bucharest, Romania; Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest, 050095, Romania.
| | - Luciana Stănică
- International Centre of Biodynamics, Intr. Portocalelor 1 B, 060101, Bucharest, Romania; Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest, 050095, Romania
| | - Miruna G Ghinia Tegla
- Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, 400084, Cluj-Napoca, Romania; Retinal Circuit Development & Genetics Unit N-NRL/NEI/NIH 6 Center Drive Bethesda, 20892, Maryland, United States
| | - Cristina Polonschii
- International Centre of Biodynamics, Intr. Portocalelor 1 B, 060101, Bucharest, Romania.
| | - Dumitru Bratu
- International Centre of Biodynamics, Intr. Portocalelor 1 B, 060101, Bucharest, Romania.
| | - Octavian Popescu
- Institute for Interdisciplinary Research in Bio-Nano-Sciences, Molecular Biology Center, Babes-Bolyai-University, 400084, Cluj-Napoca, Romania; Institute of Biology, Romanian Academy, 296 Splaiul Independentei, 060031, Bucharest, Romania
| | - Tudor Badea
- Retinal Circuit Development & Genetics Unit N-NRL/NEI/NIH 6 Center Drive Bethesda, 20892, Maryland, United States.
| | - Eugen Gheorghiu
- International Centre of Biodynamics, Intr. Portocalelor 1 B, 060101, Bucharest, Romania; Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, Bucharest, 050095, Romania.
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Stimulation of Na +/K +-ATPase with an Antibody against Its 4 th Extracellular Region Attenuates Angiotensin II-Induced H9c2 Cardiomyocyte Hypertrophy via an AMPK/SIRT3/PPAR γ Signaling Pathway. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4616034. [PMID: 31636805 PMCID: PMC6766118 DOI: 10.1155/2019/4616034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 07/09/2019] [Accepted: 08/02/2019] [Indexed: 02/06/2023]
Abstract
Activation of the renin-angiotensin system (RAS) contributes to the pathogenesis of cardiovascular diseases. Sodium potassium ATPase (NKA) expression and activity are often regulated by angiotensin II (Ang II). This study is aimed at investigating whether DR-Ab, an antibody against 4th extracellular region of NKA, can protect Ang II-induced cardiomyocyte hypertrophy. Our results showed that Ang II treatment significantly reduced NKA activity and membrane expression. Pretreatment with DR-Ab preserved cell size in Ang II-induced cardiomyopathy by stabilizing the plasma membrane expression of NKA and restoring its activity. DR-Ab reduced intracellular ROS generation through inhibition of NADPH oxidase activity and protection of mitochondrial functions in Ang II-treated H9c2 cardiomyocytes. Pharmacological manipulation and Western blotting analysis demonstrated the cardioprotective effects were mediated by the activation of the AMPK/Sirt-3/PPARγ signaling pathway. Taken together, our results suggest that dysfunction of NKA is an important mechanism for Ang II-induced cardiomyopathy and DR-Ab may be a novel and promising therapeutic approach to treat cardiomyocyte hypertrophy.
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Frustaci A, Letizia C, Verardo R, Grande C, Francone M, Sansone L, Russo MA, Chimenti C. Primary aldosteronism-associated cardiomyopathy: Clinical-pathologic impact of aldosterone normalization. Int J Cardiol 2019; 292:141-147. [PMID: 31256994 DOI: 10.1016/j.ijcard.2019.06.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/03/2019] [Accepted: 06/19/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Primary aldosteronism (PA) causes a cardiomyopathy (CM) which substrate and evolution after aldosterone normalization are unreported. METHODS Four male patients with aldosterone-secreting adrenal adenoma and cardiomyopathy (PACM, group A) were evaluated with 2D-echo, Magnetic Resonance (CMR), coronary angiography and left ventricular endomyocardial biopsy. Biopsy samples were processed for histology, electron microscopy, immunohistochemistry, and Western Blot analysis of myocardial aldosterone receptors and aquaporin 1 and 4. Results were compared with endomyocardial samples from 5 patients with hypertensive cardiomyopathy of equivalent severity and normal plasma aldosterone (group B) and surgical samples from 5 controls (group C). One PACM patient was re-examined with CMR and endomyocardial biopsy 12 months after adrenalectomy with aldosterone and cardiac normalization. RESULTS Coronary arteries were normal in all. Group A showed prominent myocardial hypertrophy and fibrosis, with water accumulation in the cytosol and organelles of cardiomyocytes and microvascular smooth muscle cells, associated to reduced myofibril concentration and 2.8-fold increase in myocardial aldosterone receptors and aquaporin 1. At CMR, LGE areas were diffusely present. After aldosterone normalization, cardiomyocyte diameter reduced with disappearance of intracellular vacuoles, recovery of electron-density of cytosol and cell organelles, and myofibrillar content, persisting fibrosis and down-regulation of aldosterone receptors and aquaporin 1 channels. At CMR, myocardial mass reduced with recovery of cardiac contractility. LGE signal remained unchanged. CONCLUSION PACM is a reversible entity characterized by over-expression of aldosterone receptors and aquaporin 1. It induces a reversible intracellular water overloading causing impaired cardiomyocyte relaxation, contraction and ultrastructural integrity.
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Affiliation(s)
- Andrea Frustaci
- Department of Cardiovascular, Respiratory, Nephrologic, Anesthesiologic and Geriatric Sciences, La Sapienza University, Italy; Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, Rome, Italy.
| | - Claudio Letizia
- Department of Translational and Precision Medicine, Center for Secondary Hypertension, La Sapienza University, Italy
| | - Romina Verardo
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, Rome, Italy
| | - Claudia Grande
- Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, Rome, Italy
| | - Marco Francone
- Department of Radiological, Oncological and Pathological Sciences, La Sapienza University, Rome, Italy
| | - Luigi Sansone
- Cellular and Molecular Pathology Lab, IRCCS S. Raffaele Pisana, Rome, Italy
| | - Matteo Antonio Russo
- Cellular and Molecular Pathology Lab, IRCCS S. Raffaele Pisana, Rome, Italy; MEBIC Consortium, San Raffaele Open University, Rome, Italy
| | - Cristina Chimenti
- Department of Cardiovascular, Respiratory, Nephrologic, Anesthesiologic and Geriatric Sciences, La Sapienza University, Italy; Cellular and Molecular Cardiology Lab, IRCCS L. Spallanzani, Rome, Italy
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Zhang C, Zhang A, Hou W, Li T, Wang K, Zhang Q, de la Fuente JM, Jin W, Cui D. Mimicking Pathogenic Invasion with the Complexes of Au 22(SG) 18-Engineered Assemblies and Folic Acid. ACS NANO 2018; 12:4408-4418. [PMID: 29723464 DOI: 10.1021/acsnano.8b00196] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Biological systems provide the richest spectrum of sophisticated design for materials engineering. We herein provide a paradigm of Au22(SG)18-engineered (SG, glutathione thiolate) and hydrogen bonds engaged assemblies for mimicking capsid protein self-assembly. The water-evaporation-induced self-assembly method allows discrete ultrasmall gold nanoclusters (GNCs) to be self-assembled into super-GNCs assemblies (SGNCs) ranging from nano-, meso- to microscale in water-dimethyl sulfoxide binary solvents in a template-free manner. After removing free and hydration layer water molecules, the formation of SGNCs is engaged by the collective cohesion of hydrogen bonds between glutathione ligands of gradually approaching GNCs. Then, a series of tightly orchestrated cellular events induced by the complexes of Au22(SG)18-engineered assemblies and folic acid are demonstrated to mimic the invasion of eukaryotic cells by pathogens. First, the activation of macropinocytosis mimics the macropinocytic entry used by the pathogens to invade host cells. Then the cytoplasmic vacuolization is a mimicry of vacuolating effects induced by the oligomeric vacuolating toxins secreted by some bacteria. Lastly, the escaping from macropinosomes into cytosol is in a vacuolating toxin's strategy. The findings demonstrate the capabilities of artificial pathogens to emulate the structures and functions of natural pathogens.
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Affiliation(s)
- Chunlei Zhang
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
- National Center for Translational Medicine, Collaborative Innovational Center for System Biology , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Amin Zhang
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Wenxiu Hou
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Tianliang Li
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Kan Wang
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Qian Zhang
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Jesús M de la Fuente
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
- Instituto de Ciencia de Materiales de Aragón (ICMA-CSIC) , Universidad de Zaragoza & CIBER-BBN , 50009 Zaragoza , Spain
| | - Weilin Jin
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
| | - Daxiang Cui
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Instrument for Diagnosis and Therapy, Department of Instrument Science & Engineering, School of Electronic Information and Electrical Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
- National Center for Translational Medicine, Collaborative Innovational Center for System Biology , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China
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Squecco R, Luciani P, Idrizaj E, Deledda C, Benvenuti S, Giuliani C, Fibbi B, Peri A, Francini F. Hyponatraemia alters the biophysical properties of neuronal cells independently of osmolarity: a study on Ni(2+) -sensitive current involvement. Exp Physiol 2018; 101:1086-100. [PMID: 27307205 DOI: 10.1113/ep085806] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/13/2016] [Indexed: 12/28/2022]
Abstract
What is the central question of this study? Hyponatraemia, an electrolyte disorder encountered in hospitalized patients, can cause neurological symptoms usually attributed to a reduction in plasma osmolarity. Here, we investigated whether low [Na(+) ] per se can cause neuronal changes independent of osmolarity, focusing on involvement of the Na(+) -Ca(2+) exchanger. What is the main finding and its importance? We show that hyponatraemia per se causes alterations of neuronal properties. The novel finding of Na(+) -Ca(2+) exchanger involvement helps us to elucidate the volume regulation following hyponatraemia. This might have relevance in a translational perspective because Na(+) -Ca(2+) exchanger could be a target for novel therapies. Hyponatraemia is the most frequent electrolyte disorder encountered in hospitalized patients, and it can cause a wide variety of neurological symptoms. Most of the negative effects of this condition on neuronal cells are attributed to cell swelling because of the reduction of plasma osmolarity, although in hyponatraemia different membrane proteins are supposed to be involved in the conservation of neuronal volume. We have recently reported detrimental effects of hyponatraemia on two different neuronal cell lines, SK-N-AS and SH-SY5Y, independent of osmotic alterations. In this study we investigated, in the same cell lines, whether hyponatraemic conditions per se can cause electrophysiological alterations and whether these effects vary over time. Accordingly, we carried out experiments in low-sodium medium in either hyposmotic [Osm(-)] or isosmotic [Osm(+)] conditions, for a short (24 h) or long time (7 days). Using a patch pipette in voltage-clamp conditions, we recorded possible modifications of cell capacitance (Cm ) and membrane conductance (Gm ). Our results indicate that in both Osm(-) and Osm(+) medium, Cm and Gm show a similar increase, but such effects are dependent on the time in culture in different ways. Notably, regarding the possible mechanisms involved in the maintenance of Cm , Gm and Gm /Cm in Osm(+) conditions, we observed a greater contribution of the Na(+) -Ca(2+) exchanger compared with Osm(-) and control conditions. Overall, these novel electrophysiological results help us to understand the mechanisms of volume regulation after ionic perturbation. Our results might also have relevance in a translational perspective because the Na(+) -Ca(2+) exchanger can be considered a target for planning novel therapies.
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Affiliation(s)
- Roberta Squecco
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, 50134, Florence, Italy
| | - Paola Luciani
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Eglantina Idrizaj
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, 50134, Florence, Italy
| | - Cristiana Deledda
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Susanna Benvenuti
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Corinna Giuliani
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Benedetta Fibbi
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Alessandro Peri
- Department of Experimental and Clinical Biomedical Sciences 'Mario Serio', University of Florence, 50134, Florence, Italy
| | - Fabio Francini
- Department of Experimental and Clinical Medicine, Section of Physiological Sciences, University of Florence, 50134, Florence, Italy
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