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Suárez V, Picotin R, Fassbender R, Gramespacher H, Haneder S, Persigehl T, Todorova P, Hackl MJ, Onur OA, Richter N, Burst V. Chronic Hyponatremia and Brain Structure and Function Before and After Treatment. Am J Kidney Dis 2024; 84:38-48.e1. [PMID: 38184092 DOI: 10.1053/j.ajkd.2023.11.007] [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: 05/24/2023] [Revised: 11/02/2023] [Accepted: 11/14/2023] [Indexed: 01/08/2024]
Abstract
RATIONALE & OBJECTIVE Hyponatremia is the most common electrolyte disorder and is associated with significant morbidity and mortality. This study investigated neurocognitive impairment, brain volume, and alterations in magnetic resonance imaging (MRI)-based measures of cerebral function in patients before and after treatment for hyponatremia. STUDY DESIGN Prospective cohort study. SETTING & PARTICIPANTS Patients with presumed chronic hyponatremia without signs of hypo- or hypervolemia treated in the emergency department of a German tertiary-care hospital. EXPOSURE Hyponatremia (ie, plasma sodium concentration [Na+]<125mmol/L) before and after treatment leading to [Na+]>130mmol/L. OUTCOMES Standardized neuropsychological testing (Mini-Mental State Examination, DemTect, Trail Making Test A/B, Beck Depression Inventory, Timed Up and Go) and resting-state MRI were performed before and after treatment of hyponatremia to assess total brain and white and gray matter volumes as well as neuronal activity and its synchronization. ANALYTICAL APPROACH Changes in outcomes after treatment for hyponatremia assessed using bootstrapped confidence intervals and Cohen d statistic. Associations between parameters were assessed using correlation analyses. RESULTS During a 3.7-year period, 26 patients were enrolled. Complete data were available for 21 patients. Mean [Na+]s were 118.4mmol/L before treatment and 135.5mmol/L after treatment. Most measures of cognition improved significantly. Comparison of MRI studies showed a decrease in brain tissue volumes, neuronal activity, and synchronization across all gray matter after normalization of [Na+]. Volume effects were particularly prominent in the hippocampus. During hyponatremia, synchronization of neuronal activity was negatively correlated with [Na+] (r=-0.836; 95% CI, -0.979 to-0.446) and cognitive function (Mini-Mental State Examination, r=-0.523; 95% CI, -0.805 to-0.069; DemTect, r=-0.744; 95% CI, -0.951 to-0.385; and Trail Making Test A, r=0.692; 95% CI, 0.255-0.922). LIMITATIONS Small sample size, insufficient quality of several MRI scans as a result of motion artifact. CONCLUSIONS Resolution of hyponatremia was associated with improved cognition and reductions in brain volumes and neuronal activity. Impaired cognition during hyponatremia is closely linked to increased neuronal activity rather than to tissue volumes. Furthermore, the hippocampus appears to be particularly susceptible to hyponatremia, exhibiting pronounced changes in tissue volume. PLAIN-LANGUAGE SUMMARY Hyponatremia is a common clinical problem, and patients often present with neurologic symptoms that are at least partially reversible. This study used neuropsychological testing and magnetic resonance imaging to examine patients during and after correction of hyponatremia. Treatment led to an improvement in patients' cognition as well as a decrease in their brain volumes, spontaneous neuronal activity, and synchronized neuronal activity between remote brain regions. Volume effects were particularly prominent in the hippocampus, an area of the brain that is important for the modulation of memory. During hyponatremia, patients with the lowest sodium concentrations had the highest levels of synchronized neuronal activity and the poorest cognitive test results.
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Affiliation(s)
- Victor Suárez
- Department II of Internal Medicine (Nephrology, Rheumatology, Diabetes, and General Internal Medicine) and Center for Molecular Medicine Cologne, Cologne, Germany; Emergency Department, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Rosanne Picotin
- Department of Neurology, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Ronja Fassbender
- Department of Neurology, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Hannes Gramespacher
- Department of Neurology, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stefan Haneder
- Department of Diagnostic and Interventional Radiology, University of Cologne, Cologne, Germany
| | - Thorsten Persigehl
- Department of Diagnostic and Interventional Radiology, University of Cologne, Cologne, Germany
| | - Polina Todorova
- Department II of Internal Medicine (Nephrology, Rheumatology, Diabetes, and General Internal Medicine) and Center for Molecular Medicine Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Matthias Johannes Hackl
- Department II of Internal Medicine (Nephrology, Rheumatology, Diabetes, and General Internal Medicine) and Center for Molecular Medicine Cologne, Cologne, Germany; Emergency Department, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Oezguer A Onur
- Department of Neurology, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany; Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Jülich, Germany
| | - Nils Richter
- Department of Neurology, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Volker Burst
- Department II of Internal Medicine (Nephrology, Rheumatology, Diabetes, and General Internal Medicine) and Center for Molecular Medicine Cologne, Cologne, Germany; Emergency Department, University of Cologne, Cologne, Germany; Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
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Gong J, Li Q. Comparative Transcriptome and WGCNA Analysis Reveal Molecular Responses to Salinity Change in Larvae of the Iwagaki Oyster Crassostrea Nippona. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023; 25:1031-1042. [PMID: 37872465 DOI: 10.1007/s10126-023-10257-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
The Iwagaki oyster Crassostrea nippona is an important aquaculture species with significant potential for large-scale oyster farming. It is susceptible to the fluctuated salinity in the coastal area. In this study, we compared the transcriptome of Crassostrea nippona larvae under variant conditions with low-salinity stress (28, 20, 15, 10, and 5 practical salinity units (psu)) for 24 h. KEGG enrichment analysis of differentially expressed genes (DEGs) from pairwise comparisons identified several free amino acid metabolism pathway (taurine and hypotaurine, arginine and proline, glycine, and beta-alanine) contributing to the salinity change adaptation and activated "lysosome" and "apoptosis" pathway in response to the low-salinity stress (10 and 5 psu). Trend analysis revealed sustained upregulation of transmembrane transport-related genes (such as SLC family) and downregulation of ribosomal protein synthesis genes faced with decreasing salinities. In addition, 9 biomarkers in response to low-salinity stress were identified through weighted gene co-expression network analysis (WGCNA) and validated by qRT-PCR. Our transcriptome analysis provides a comprehensive view of the molecular mechanisms and regulatory networks underlying the adaptive responses of oyster larvae to hypo-salinity conditions. These findings contribute to our understanding of the complex biological processes involved in oyster resilience and adaptation to changing environmental conditions.
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Affiliation(s)
- Jianwen Gong
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China
| | - Qi Li
- Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China.
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Kaufman DA, Lopes M, Maviya N, Magder SA. The Ins and Outs of IV Fluids in Hemodynamic Resuscitation. Crit Care Med 2023; 51:1397-1406. [PMID: 37707377 DOI: 10.1097/ccm.0000000000006001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
OBJECTIVES Concise definitive review of the physiology of IV fluid (IVF) use in critically ill patients. DATA SOURCES Available literature on PubMed and MEDLINE databases. STUDY SELECTION Basic physiology studies, observational studies, clinical trials, and reviews addressing the physiology of IVF and their use in the critically ill were included. DATA EXTRACTION None. DATA SYNTHESIS We combine clinical and physiologic studies to form a framework for understanding rational and science-based use of fluids and electrolytes. CONCLUSIONS IVF administration is among the most common interventions for critically ill patients. IVF can be classified as crystalloids or colloids, and most crystalloids are sodium salts. They are frequently used to improve hemodynamics during shock states. Many recent clinical trials have sought to understand which kind of IVF might lead to better patient outcomes, especially in sepsis. Rational use of IVF rests on understanding the physiology of the shock state and what to expect IVF will act in those settings. Many questions remain unanswered, and future research should include a physiologic understanding of IVF in study design.
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Affiliation(s)
- David A Kaufman
- Division of Pulmonary and Critical Care Medicine, NYU Grossman School of Medicine, New York, NY
| | - Marcela Lopes
- Intensive Care Unit, Hospital da Cidade, Salvador, Bahia, Brazil
| | | | - Sheldon A Magder
- Department of Critical Care, McGill University Health Centre, Montréal, Québec, Canada
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Gankam Kengne F. Adaptation of the Brain to Hyponatremia and Its Clinical Implications. J Clin Med 2023; 12:jcm12051714. [PMID: 36902500 PMCID: PMC10002753 DOI: 10.3390/jcm12051714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/12/2023] [Accepted: 02/17/2023] [Indexed: 02/25/2023] Open
Abstract
Hyponatremia is the most common electrolyte disorder, occurring in up to 25% of hospitalized patients. Hypo-osmotic hyponatremia when severe and left untreated invariably results in cell swelling, which can lead to fatal consequences, especially in the central nervous system. The brain is particularly vulnerable to the consequences of decreased extracellular osmolarity; because of being encased in the rigid skull, it cannot withstand persistent swelling. Moreover, serum sodium is the major determinant of extracellular ionic balance, which in turn governs crucial brain functions such as the excitability of neurons. For these reasons, the human brain has developed specific ways to adapt to hyponatremia and prevent brain edema. On the other hand, it is well known that rapid correction of chronic and severe hyponatremia can lead to brain demyelination, a condition known as osmotic demyelination syndrome. In this paper, we will discuss the mechanisms of brain adaptation to acute and chronic hyponatremia and the neurological symptoms of these conditions as well as the pathophysiology and prevention of osmotic demyelination syndrome.
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Aleksandrowicz M, Kozniewska E. Hyponatremia as a risk factor for microvascular spasm following subarachnoid hemorrhage. Exp Neurol 2022; 355:114126. [DOI: 10.1016/j.expneurol.2022.114126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/20/2022] [Accepted: 05/25/2022] [Indexed: 11/04/2022]
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Sung CC, Chen HC, Lin YC, Chan LC, Lin SH. Clinical analysis for osmotic demyelination syndrome in patients with chronic hyponatremia. JOURNAL OF MEDICAL SCIENCES 2022. [DOI: 10.4103/jmedsci.jmedsci_165_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Fibbi B, Marroncini G, Anceschi C, Naldi L, Peri A. Hyponatremia and Oxidative Stress. Antioxidants (Basel) 2021; 10:1768. [PMID: 34829639 PMCID: PMC8614907 DOI: 10.3390/antiox10111768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
Hyponatremia, i.e., the presence of a serum sodium concentration ([Na+]) < 136 mEq/L, is the most frequent electrolyte imbalance in the elderly and in hospitalized patients. Symptoms of acute hyponatremia, whose main target is the central nervous system, are explained by the "osmotic theory" and the neuronal swelling secondary to decreased extracellular osmolality, which determines cerebral oedema. Following the description of neurological and systemic manifestations even in mild and chronic hyponatremia, in the last decade reduced extracellular [Na+] was associated with detrimental effects on cellular homeostasis independently of hypoosmolality. Most of these alterations appeared to be elicited by oxidative stress. In this review, we focus on the role of oxidative stress on both osmolality-dependent and -independent impairment of cell and tissue functions observed in hyponatremic conditions. Furthermore, basic and clinical research suggested that oxidative stress appears to be a common denominator of the degenerative processes related to aging, cancer progression, and hyponatremia. Of note, low [Na+] is able to exacerbate multiple manifestations of senescence and to decrease progression-free and overall survival in oncologic patients.
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Affiliation(s)
- Benedetta Fibbi
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Giada Marroncini
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Cecilia Anceschi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Laura Naldi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Alessandro Peri
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
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Ergun DD, Dursun S, Ergun S, Ozcelik D. The Association Between Trace Elements and Osmolality in Plasma and Aqueous Humor Fluid in Diabetic Rabbits. Biol Trace Elem Res 2021; 199:4154-4161. [PMID: 33409916 DOI: 10.1007/s12011-020-02538-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/09/2020] [Indexed: 10/22/2022]
Abstract
Trace element metabolism plays an important role in the formation of diabetes and complications of diabetes. Although trace elements changes in lenses in diabetic cataract and glaucoma formation have been investigated, there were few studies evaluating trace elements levels in plasma and aqueous humor fluid in diabetic and non-diabetic conditions. Therefore, we aimed to investigate zinc (Zn), copper (Cu), and chromium (Cr) levels in plasma and aqueous humor fluids of rabbits in the diabetic rabbit model. New Zealand male rabbits were divided into two groups as control (n = 8), and diabetes (n = 8) induced by alloxane. At the end of the experimental period, the osmolality in blood, plasma, and aqueous humor fluids from rabbits were measured by osmometer and Zn, Cu, and Cr levels in plasma and aqueous humor fluid were measured by inductively coupled plasma-optical emission spectrophotometer (ICP-OES). The osmolality in blood, plasma, and aqueous humor fluid of the diabetic group was significantly increased compared to the control group (respectively p < 0.01, p < 0.001, p < 0.001). It was analyzed that plasma Zn and Cu levels of diabetic rabbits increased significantly (respectively, p < 0.01; p < 0.001), whereas Cr level significantly decreased according to the control group (p < 0.01). It was observed that Cr and Zn levels in aqueous humor fluid in diabetes group decreased (respectively p < 0.001 and p < 0.01), and a significantly increased in Cu level (p < 0.001) compared to the control group. Related with these changes that may occur in the eye due to the measured parameters, we consider that comparative studies of these types of diabetic animal models would be useful in the evaluation of diabetes and its complications.
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Affiliation(s)
- Dilek Duzgun Ergun
- Department of Biophysics, Faculty of Medicine, Istanbul Aydin University, Istanbul, Turkey.
- Department of Biophysics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey.
| | - Sefik Dursun
- Department of Biophysics, Medical Faculty, Uskudar University, Istanbul, Turkey
| | - Sefa Ergun
- Department of General Surgery, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Dervis Ozcelik
- Department of Biophysics, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
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Chen C, Tutol JN, Tang L, Zhu L, Ong WSY, Dodani SC, Fang C. Excitation ratiometric chloride sensing in a standalone yellow fluorescent protein is powered by the interplay between proton transfer and conformational reorganization. Chem Sci 2021; 12:11382-11393. [PMID: 34667546 PMCID: PMC8447875 DOI: 10.1039/d1sc00847a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Natural and laboratory-guided evolution has created a rich diversity of fluorescent protein (FP)-based sensors for chloride (Cl−). To date, such sensors have been limited to the Aequorea victoria green fluorescent protein (avGFP) family, and fusions with other FPs have unlocked ratiometric imaging applications. Recently, we identified the yellow fluorescent protein from jellyfish Phialidium sp. (phiYFP) as a fluorescent turn-on, self-ratiometric Cl− sensor. To elucidate its working mechanism as a rare example of a single FP with this capability, we tracked the excited-state dynamics of phiYFP using femtosecond transient absorption (fs-TA) spectroscopy and target analysis. The photoexcited neutral chromophore undergoes bifurcated pathways with the twisting-motion-induced nonradiative decay and barrierless excited-state proton transfer. The latter pathway yields a weakly fluorescent anionic intermediate , followed by the formation of a red-shifted fluorescent state that enables the ratiometric response on the tens of picoseconds timescale. The redshift results from the optimized π–π stacking between chromophore Y66 and nearby Y203, an ultrafast molecular event. The anion binding leads to an increase of the chromophore pKa and ESPT population, and the hindrance of conversion. The interplay between these two effects determines the turn-on fluorescence response to halides such as Cl− but turn-off response to other anions such as nitrate as governed by different binding affinities. These deep mechanistic insights lay the foundation for guiding the targeted engineering of phiYFP and its derivatives for ratiometric imaging of cellular chloride with high selectivity. We discovered an interplay between proton transfer and conformational reorganization that powers a standalone fluorescent-protein-based excitation-ratiometric biosensor for chloride imaging.![]()
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Longteng Tang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Whitney S Y Ong
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Chong Fang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
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Bustamante HA, Ehrich MF, Klein BG. Intracellular potassium depletion enhances apoptosis induced by staurosporine in cultured trigeminal satellite glial cells. Somatosens Mot Res 2021; 38:194-201. [PMID: 34187291 DOI: 10.1080/08990220.2021.1941843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Satellite glial cells (SGC) surrounding neurons in sensory ganglia can buffer extracellular potassium, regulating the excitability of injured neurons and possibly influencing a shift from acute to neuropathic pain. SGC apoptosis may be a key component in this process. This work evaluated induction or enhancement of apoptosis in cultured trigeminal SGC following changes in intracellular potassium [K]ic. MATERIALS AND METHODS We developed SGC primary cultures from rat trigeminal ganglia (TG). Purity of our cultures was confirmed using immunofluorescence and western blot analysis for the presence of the specific marker of SGC, glutamine synthetase (GS). SGC [K]ic was depleted using hypo-osmotic shock and 4 mM bumetanide plus 10 mM ouabain. [K]ic was measured using the K+ fluorescent indicator potassium benzofuran isophthalate (PBFI-AM). RESULTS SGC tested positive for GS and hypo-osmotic shock induced a significant decrease in [K]ic at every evaluated time. Cells were then incubated for 5 h with either 2 mM staurosporine (STS) or 20 ng/ml of TNF-α and evaluated for early apoptosis and late apoptosis/necrosis by flow cytometry using annexin V and propidium iodide. A significant increase in early apoptosis, from 16 to 38%, was detected in SGC with depleted [K]ic after incubation with STS. In contrast, TNF-α did not increase early apoptosis in normal or [K]ic depleted SGC. CONCLUSION Hypo-osmotic shock induced a decrease in intracellular potassium in cultured trigeminal SGC and this enhanced apoptosis induced by STS that is associated with the mitochondrial pathway. These results suggest that K+ dysregulation may underlie apoptosis in trigeminal SGC.
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Affiliation(s)
- Hedie A Bustamante
- Faculty of Veterinary Sciences, Veterinary Clinical Sciences Institute, Universidad Austral de Chile, Valdivia, Chile
| | - Marion F Ehrich
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Bradley G Klein
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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11
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Kawakami T, Fujisawa H, Nakayama S, Yoshino Y, Hattori S, Seino Y, Takayanagi T, Miyakawa T, Suzuki A, Sugimura Y. Vasopressin escape and memory impairment in a model of chronic syndrome of inappropriate secretion of antidiuretic hormone in mice. Endocr J 2021; 68:31-43. [PMID: 32879162 DOI: 10.1507/endocrj.ej20-0289] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Recently, chronic hyponatremia, even mild, has shown to be associated with poor quality of life and high mortality. The mechanism by which hyponatremia contributes to those symptoms, however, remains to be elucidated. Syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a primary cause of hyponatremia. Appropriate animal models are crucial for investigating the pathophysiology of SIADH. A rat model of SIADH has been generally used and mouse models have been rarely used. In this study, we developed a mouse model of chronic SIADH in which stable and sustained hyponatremia occurred after 3-week continuous infusion of the vasopressin V2 receptor agonist 1-desamino-8-D-arginine vasopressin (dDAVP) and liquid diet feeding to produce chronic water loading. Weight gain in chronic SIADH mice at week 2 and 3 after starting dDAVP injection was similar to that of control mice, suggesting that the animals adapted to chronic hyponatremia and grew up normally. AQP2 expression in the kidney, which reflects the renal action of vasopressin, was decreased in dDAVP-infused water-loaded mice as compared with control mice that received the same dDAVP infusion but were fed pelleted chow. These results suggest that "vasopressin escape" occurred, which is an important process for limiting potentially fatal severe hyponatremia. Behavioral analyses using the contextual and cued fear conditioning test and T-maze test demonstrated cognitive impairment, especially working memory impairment, in chronic SIADH mice, which was partially restored after correcting hyponatremia. Our results suggest that vasopressin escape occurred in chronic SIADH mice and that chronic hyponatremia contributed to their memory impairment.
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Affiliation(s)
- Tsukasa Kawakami
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Haruki Fujisawa
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Shogo Nakayama
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Yasumasa Yoshino
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Satoko Hattori
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Yusuke Seino
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Takeshi Takayanagi
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Atsushi Suzuki
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | - Yoshihisa Sugimura
- Department of Endocrinology and Metabolism, Fujita Health University, Toyoake, Aichi 470-1192, Japan
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Fajrial AK, Liu K, Gao Y, Gu J, Lakerveld R, Ding X. Characterization of Single-Cell Osmotic Swelling Dynamics for New Physical Biomarkers. Anal Chem 2021; 93:1317-1325. [PMID: 33253534 DOI: 10.1021/acs.analchem.0c02289] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Characterization of cell physical biomarkers is vital to understand cell properties and applicable for disease diagnostics. Current methods used to analyze physical phenotypes involve external forces to deform the cells. Alternatively, internal tension forces via osmotic swelling can also deform the cells. However, an established assumption contends that the forces generated during hypotonic swelling concentrated on the plasma membrane are incapable of assessing the physical properties of nucleated cells. Here, we utilized an osmotic swelling approach to characterize different types of nucleated cells. Using a microfluidic device for cell trapping arrays with truncated hanging micropillars (CellHangars), we isolated single cells and evaluated the swelling dynamics during the hypotonic challenge at 1 s time resolution. We demonstrated that cells with different mechanical phenotypes showed unique swelling dynamics signature. Different types of cells can be classified with an accuracy of up to ∼99%. We also showed that swelling dynamics can detect cellular mechanical property changes due to cytoskeleton disruption. Considering its simplicity, swelling dynamics offers an invaluable label-free physical biomarker for cells with potential applications in both biological studies and clinical practice.
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Affiliation(s)
- Apresio K Fajrial
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States
| | - Kun Liu
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States
| | - Yu Gao
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States
| | - Junhao Gu
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Richard Lakerveld
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Xiaoyun Ding
- Paul M. Rady Department of Mechanical Engineering, University of Colorado Boulder, 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309, United States.,Biomedical Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
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13
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Maiolo L, Guarino V, Saracino E, Convertino A, Melucci M, Muccini M, Ambrosio L, Zamboni R, Benfenati V. Glial Interfaces: Advanced Materials and Devices to Uncover the Role of Astroglial Cells in Brain Function and Dysfunction. Adv Healthc Mater 2021; 10:e2001268. [PMID: 33103375 DOI: 10.1002/adhm.202001268] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/06/2020] [Indexed: 12/13/2022]
Abstract
Research over the past four decades has highlighted the importance of certain brain cells, called glial cells, and has moved the neurocentric vision of structure, function, and pathology of the nervous system toward a more holistic perspective. In this view, the demand for technologies that are able to target and both selectively monitor and control glial cells is emerging as a challenge across neuroscience, engineering, chemistry, and material science. Frequently neglected or marginally considered as a barrier to be overcome between neural implants and neuronal targets, glial cells, and in particular astrocytes, are increasingly considered as active players in determining the outcomes of device implantation. This review provides a concise overview not only of the previously established but also of the emerging physiological and pathological roles of astrocytes. It also critically discusses the most recent advances in biomaterial interfaces and devices that interact with glial cells and thus have enabled scientists to reach unprecedented insights into the role of astroglial cells in brain function and dysfunction. This work proposes glial interfaces and glial engineering as multidisciplinary fields that have the potential to enable significant advancement of knowledge surrounding cognitive function and acute and chronic neuropathologies.
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Affiliation(s)
- Luca Maiolo
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Vincenzo Guarino
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Emanuela Saracino
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Annalisa Convertino
- Consiglio Nazionale delle Ricerche Istituto per la Microelettronica e i Microsistemi Via del Fosso del Cavaliere n.100 Roma 00133 Italy
| | - Manuela Melucci
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Michele Muccini
- Consiglio Nazionale delle Ricerche Istituto per la Studio dei Materiali Nanostrutturati via P. Gobetti 101 Bologna 40129 Italy
| | - Luigi Ambrosio
- Consiglio Nazionale delle Ricerche Istituto per i Polimeri Compositi e Biomateriali Viale J.F. Kennedy 54, Mostra d'Oltremare, Pad 20 Napoli 80125 Italy
| | - Roberto Zamboni
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
| | - Valentina Benfenati
- Consiglio Nazionale delle Ricerche Istituto per la Sintesi Organica e la Fotoreattività via P. Gobetti 101 Bologna 40129 Italy
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Wang SC, Parpura V, Wang YF. Astroglial Regulation of Magnocellular Neuroendocrine Cell Activities in the Supraoptic Nucleus. Neurochem Res 2020; 46:2586-2600. [PMID: 33216313 DOI: 10.1007/s11064-020-03172-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 01/02/2023]
Abstract
Studies on the interactions between astrocytes and neurons in the hypothalamo-neurohypophysial system have significantly facilitated our understanding of the regulation of neural activities. This has been exemplified in the interactions between astrocytes and magnocellular neuroendocrine cells (MNCs) in the supraoptic nucleus (SON), specifically during osmotic stimulation and lactation. In response to changes in neurochemical environment in the SON, astrocytic morphology and functions change significantly, which further modulates MNC activity and the secretion of vasopressin and oxytocin. In osmotic regulation, short-term dehydration or water overload causes transient retraction or expansion of astrocytic processes, which increases or decreases the activity of SON neurons, respectively. Prolonged osmotic stimulation causes adaptive change in astrocytic plasticity in the SON, which allows osmosensory neurons to reserve osmosensitivity at new levels. During lactation, changes in neurochemical environment cause retraction of astrocytic processes around oxytocin neurons, which increases MNC's ability to secrete oxytocin. During suckling by a baby/pup, astrocytic processes in the mother/dams exhibit alternative retraction and expansion around oxytocin neurons, which mirrors intermittently synchronized activation of oxytocin neurons and the post-excitation inhibition, respectively. The morphological and functional plasticities of astrocytes depend on a series of cellular events involving glial fibrillary acidic protein, aquaporin 4, volume regulated anion channels, transporters and other astrocytic functional molecules. This review further explores mechanisms underlying astroglial regulation of the neuroendocrine neuronal activities in acute processes based on the knowledge from studies on the SON.
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Affiliation(s)
- Stephani C Wang
- Division of Cardiology, Department of Medicine, University of California-Irvine, Irvine, CA, USA
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, 35242, USA.
| | - Yu-Feng Wang
- Department of Physiology School of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang, Harbin, 150086, China.
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15
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Leong XF, Cheng M, Jong B, Hwang NC, Roscoe A. Sodium Abnormalities in Cardiac Surgery With Cardiopulmonary Bypass in Adults: A Narrative Review. J Cardiothorac Vasc Anesth 2020; 35:3374-3384. [PMID: 32888797 DOI: 10.1053/j.jvca.2020.07.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 11/11/2022]
Abstract
Perioperative sodium abnormalities or dysnatremia is not uncommon in patients presenting for cardiac surgery and is associated with increased morbidity and mortality. Both the disease process of heart failure and its treatment may contribute to abnormalities in serum sodium concentration. Serum sodium is the main determinant of serum osmolality, which in turn affects cell volume. Brain cells are particularly vulnerable to changes in serum osmolality because of the nondistensible cranium. The potentially catastrophic neurologic sequelae of rapidly correcting chronic dysnatremia and the time-sensitive nature of cardiac surgery can make the management of these patients challenging. The use of cardiopulmonary bypass to facilitate surgery adds another layer of complexity in the intraoperative management of sodium and water balance. This narrative review examines the definition and classification of dysnatremia. It also covers the etiology and pathophysiology of dysnatremia, implications during cardiac surgery requiring cardiopulmonary bypass, and the perioperative management of dysnatremia.
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Affiliation(s)
- Xin Fang Leong
- Department of Anaesthesiology, Singapore General Hospital, Singapore; Department of Cardiothoracic Anaesthesia, National Heart Centre, Singapore
| | - Maureen Cheng
- Department of Anaesthesiology, Singapore General Hospital, Singapore; Department of Cardiothoracic Anaesthesia, National Heart Centre, Singapore
| | - Bronte Jong
- Department of Anaesthesiology, Singapore General Hospital, Singapore
| | - Nian Chih Hwang
- Department of Anaesthesiology, Singapore General Hospital, Singapore; Department of Cardiothoracic Anaesthesia, National Heart Centre, Singapore
| | - Andrew Roscoe
- Department of Anaesthesiology, Singapore General Hospital, Singapore; Department of Cardiothoracic Anaesthesia, National Heart Centre, Singapore.
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16
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Lisjak M, Potokar M, Zorec R, Jorgačevski J. Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles. Cells 2020; 9:cells9030735. [PMID: 32192013 PMCID: PMC7140617 DOI: 10.3390/cells9030735] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 01/10/2023] Open
Abstract
Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.
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Affiliation(s)
- Marjeta Lisjak
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
| | - Maja Potokar
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
| | - Jernej Jorgačevski
- Laboratory of Neuroendocrinology–Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia; (M.L.); (M.P.); (R.Z.)
- Celica Biomedical, Tehnološki park 24, 1000 Ljubljana, Slovenia
- Correspondence: ; Tel.: +38615437081
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Andrä I, Ulrich H, Dürr S, Soll D, Henkel L, Angerpointner C, Ritter J, Przibilla S, Stadler H, Effenberger M, Busch DH, Schiemann M. An Evaluation of T‐Cell Functionality After Flow Cytometry Sorting Revealed p38 MAPK Activation. Cytometry A 2020; 97:171-183. [DOI: 10.1002/cyto.a.23964] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 12/04/2019] [Accepted: 12/09/2019] [Indexed: 01/10/2023]
Affiliation(s)
- Immanuel Andrä
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Hanna Ulrich
- Institute for Systemic Inflammation ResearchUniversität zu Lübeck Lübeck Germany
| | - Susi Dürr
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Dominik Soll
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Lynette Henkel
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Corinne Angerpointner
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Julia Ritter
- Institute for Systemic Inflammation ResearchUniversität zu Lübeck Lübeck Germany
| | | | - Herbert Stadler
- Cell.Copedia GmbH Leipzig Germany
- IBA GmbH, IBA Lifesciences Göttingen Lower Saxony Germany
| | - Manuel Effenberger
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
| | - Dirk H. Busch
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
- Focus Group 'Clinical Cell Processing and Purification'Institute for Advanced Study, TUM Munich Germany
- National Centre for Infection Research (DZIF) Munich Germany
| | - Matthias Schiemann
- Institute for Medical Microbiology, Immunology and HygieneTechnische Universität München (TUM) Munich Germany
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18
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Abstract
Shifts between habitats during reproduction can induce costs that are independent of the reproductive effort and that often apply to both sexes. Such shifts can also illustrate physiological costs complementary to those involving energetic currencies. In this study, we investigated osmotic consequences of reproduction in a context where reproduction induces a shift from terrestrial habitats to freshwater environments. During reproduction, toads migrate to breeding ponds where males remain for several weeks, while females leave shortly after egg-laying. We assessed plasma osmolality of male spined toads during the whole reproductive period (approx. 30 days) in conjunction with markers of individual condition. We found that osmolality decreases during the protracted period of immersion in freshwater during reproduction, presumably through water influx as indicated by body mass changes. Hormonal markers of metabolism and sexual activity were positively correlated with osmolality. Recent research has highlighted hydric 'costs' of reproduction when access to water is limited. Our study adds to this growing field of investigation, yet with an opposite perspective, where water availability linked to reproduction provokes hyperhydration rather than dehydration.
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Affiliation(s)
- François Brischoux
- Centre d'Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
| | - Marion Cheron
- Centre d'Etudes Biologiques de Chizé, CEBC UMR 7372 CNRS-La Rochelle Université, 79360 Villiers en Bois, France
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Abstract
Leukodystrophies are genetically determined disorders affecting the white matter of the central nervous system. The combination of MRI pattern recognition and next-generation sequencing for the definition of novel disease entities has recently demonstrated that many leukodystrophies are due to the primary involvement and/or mutations in genes selectively expressed by cell types other than the oligodendrocytes, the myelin-forming cells in the brain. This has led to a new definition of leukodystrophies as genetic white matter disorders resulting from the involvement of any white matter structural component. As a result, the research has shifted its main focus from oligodendrocytes to other types of neuroglia. Astrocytes are the housekeeping cells of the nervous system, responsible for maintaining homeostasis and normal brain physiology and to orchestrate repair upon injury. Several lines of evidence show that astrocytic interactions with the other white matter cellular constituents play a primary pathophysiologic role in many leukodystrophies. These are thus now classified as astrocytopathies. This chapter addresses how the crosstalk between astrocytes, other glial cells, axons and non-neural cells are essential for the integrity and maintenance of the white matter in health. It also addresses the current knowledge of the cellular pathomechanisms of astrocytic leukodystrophies, and specifically Alexander disease, vanishing white matter, megalencephalic leukoencephalopathy with subcortical cysts and Aicardi-Goutière Syndrome.
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Affiliation(s)
- M S Jorge
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pathology, Free University Medical Centre, Amsterdam, The Netherlands.
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20
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Diuba AV, Samigullin DV, Kaszas A, Zonfrillo F, Malkov A, Petukhova E, Casini A, Arosio D, Esclapez M, Gross CT, Bregestovski P. CLARITY analysis of the Cl/pH sensor expression in the brain of transgenic mice. Neuroscience 2019; 439:181-194. [PMID: 31302264 DOI: 10.1016/j.neuroscience.2019.07.010] [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: 03/26/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 10/26/2022]
Abstract
Genetically encoded biosensors are widely used in cell biology for the non-invasive imaging of concentrations of ions or the activity of enzymes, to evaluate the distribution of small molecules, proteins and organelles, and to image protein interactions in living cells. These fluorescent molecules can be used either by transient expression in cultured cells or in entire organisms or through stable expression by producing transgenic animals characterized by genetically encoded and heritable biosensors. Using the mouse Thy1 mini-promoter, we generated a line of transgenic mice expressing a genetically encoded sensor for the simultaneous measurements of intracellular Cl- and pH. This construct, called ClopHensor, consists of a H+- and Cl--sensitive variant of the enhanced green fluorescent protein (E2GFP) fused with a red fluorescent protein (DsRedm). Stimulation of hippocampal Schaffer collaterals proved that the sensor is functionally active. To reveal the expression pattern of ClopHensor across the brain of Thy1::ClopHensor mice, we obtained transparent brain samples using the CLARITY method and imaged them with confocal and light-sheet microscopy. We then developed a semi-quantitative approach to identify brain structures with high intrinsic sensor fluorescence. This approach allowed us to assess cell morphology and track axonal projection, as well as to confirm E2GFP and DsRedm fluorescence colocalization. This analysis also provides a map of the brain areas suitable for non-invasive monitoring of intracellular Cl-/pH in normal and pathological conditions. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Artem V Diuba
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - Dmitry V Samigullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111, Kazan, Russia; Department of Radiophotonics and microwave technologies, Kazan National Research Technical University named after A.N.Tupolev, 420111, Kazan, Russia; Open Laboratory of Neuropharmacology, Kazan Federal University,420111, Kazan, Russia
| | - Attila Kaszas
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix- Marseille Université, 13005 Marseille, France
| | - Francesca Zonfrillo
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, EMBL-Rome, Via Ramarini 32, 00015 Monterotondo, ITALY
| | - Anton Malkov
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290, Pushchino, Russia
| | - Elena Petukhova
- Institute of Neurosciences, Kazan Medical State University, Kazan, Russia
| | | | - Daniele Arosio
- Institute of Biophysics, National Research Council of Italy, 38123 Trento, Italy
| | - Monique Esclapez
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France
| | - Cornelius T Gross
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, EMBL-Rome, Via Ramarini 32, 00015 Monterotondo, ITALY
| | - Piotr Bregestovski
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institute of Neurosciences, Kazan Medical State University, Kazan, Russia.
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Ho PT, Rhee H, Kim J, Seo C, Park JK, Young CR, Won YJ. Impacts of Salt Stress on Locomotor and Transcriptomic Responses in the Intertidal Gastropod Batillaria attramentaria. THE BIOLOGICAL BULLETIN 2019; 236:224-241. [PMID: 31167089 DOI: 10.1086/703186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Salinity is one of the most crucial environmental factors that structures biogeographic boundaries of aquatic organisms, affecting distribution, abundance, and behavior. However, the association between behavior and gene regulation underlying acclimation to changes in salinity remains poorly understood. In this study, we investigated the effects of salinity stress on behavior (movement distance) and patterns of gene expression (using RNA sequencing) of the intertidal gastropod Batillaria attramentaria. We examined responses to short-term (1-hour) and long-term (30-day) acclimation to a range of salinities (43, 33 [control], 23, 13, and 3 psu). We found that the intertidal B. attramentaria is able to tolerate a broad range of salinity from 13 to 43 psu but not the acute low salinity of 3 psu. Behavioral experiments showed that salt stress significantly influenced snails' movement, with lower salinity resulting in shorter movement distance. Transcriptomic analyses revealed critical metabolic pathways and genes potentially involved in acclimation to salinity stress, including ionic and osmotic regulation, signal and hormonal transduction pathways, water exchange, cell protection, and gene regulation or epigenetic modification. In general, our study presents a robust, integrative laboratory-based approach to investigate the effects of salt stress on a nonmodel gastropod facing detrimental consequences of environmental change. The current genetic results provide a wealth of reference data for further research on mechanisms of ionic and osmotic regulation and adaptive evolution of this coastal gastropod.
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Key Words
- AICC, corrected Akaike Information Criterion
- ATP, adenosine triphosphate
- DEG, differentially expressed gene
- FAA, free amino acid
- FDR, false discovery rate
- GABA, gamma-aminobutyric acid
- Hsp, heat shock protein
- LMM, linear mixed-effects model
- MDS, multidimensional scaling
- RNA-Seq, RNA sequencing.
- fc, fold change
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Canella R, Martini M, Cavicchio C, Cervellati F, Benedusi M, Valacchi G. Involvement of the TREK-1 channel in human alveolar cell membrane potential and its regulation by inhibitors of the chloride current. J Cell Physiol 2019; 234:17704-17713. [PMID: 30805940 DOI: 10.1002/jcp.28396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 01/03/2019] [Accepted: 01/10/2019] [Indexed: 12/14/2022]
Abstract
K+ channels of the alveolar epithelium control the driving force acting on the ionic and solvent flow through the cell membrane contributing to the maintenance of cell volume and the constitution of epithelial lining fluid. In the present work, we analyze the effect of the Cl- channel inhibitors: (4-[(2-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-inden-5-yl)oxy] butanoic acid (DCPIB) and 9-anthracenecarboxylic acid (9-AC) on the total current in a type II pneumocytes (A549 cell line) model by patch clamp, immunocytochemical, and gene knockdown techniques. We noted that DCPIB and 9-AC promote the activation of K conductance. In fact, they significantly increase the intensity of the current and shift its reversal potential to values more negative than the control. By silencing outward rectifier channel in its anoctamin 6 portion, we excluded a direct involvement of Cl- ions in modulation of IK and, by means of functional tests with its specific inhibitor spadin, we identified the TREK-1 channel as the presumable target of both drugs. As the activity of TREK-1 has a key role for the correct functioning of the alveolar epithelium, the identification of DCPIB and 9-AC molecules as its activators suggests their possible use to build new pharmacological tools for the modulation of this channel.
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Affiliation(s)
- Rita Canella
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Marta Martini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Carlotta Cavicchio
- Animal Science Department, Plants for Human Health Institute, NC State University, Kannapolis, North Carolina
| | - Franco Cervellati
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Mascia Benedusi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Giuseppe Valacchi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy.,Animal Science Department, Plants for Human Health Institute, NC State University, Kannapolis, North Carolina
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23
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Elorza-Vidal X, Sirisi S, Gaitán-Peñas H, Pérez-Rius C, Alonso-Gardón M, Armand-Ugón M, Lanciotti A, Brignone MS, Prat E, Nunes V, Ambrosini E, Gasull X, Estévez R. GlialCAM/MLC1 modulates LRRC8/VRAC currents in an indirect manner: Implications for megalencephalic leukoencephalopathy. Neurobiol Dis 2018; 119:88-99. [DOI: 10.1016/j.nbd.2018.07.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/25/2018] [Accepted: 07/28/2018] [Indexed: 01/09/2023] Open
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Wilson CS, Mongin AA. Cell Volume Control in Healthy Brain and Neuropathologies. CURRENT TOPICS IN MEMBRANES 2018; 81:385-455. [PMID: 30243438 DOI: 10.1016/bs.ctm.2018.07.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Regulation of cellular volume is a critical homeostatic process that is intimately linked to ionic and osmotic balance in the brain tissue. Because the brain is encased in the rigid skull and has a very complex cellular architecture, even minute changes in the volume of extracellular and intracellular compartments have a very strong impact on tissue excitability and function. The failure of cell volume control is a major feature of several neuropathologies, such as hyponatremia, stroke, epilepsy, hyperammonemia, and others. There is strong evidence that such dysregulation, especially uncontrolled cell swelling, plays a major role in adverse pathological outcomes. To protect themselves, brain cells utilize a variety of mechanisms to maintain their optimal volume, primarily by releasing or taking in ions and small organic molecules through diverse volume-sensitive ion channels and transporters. In principle, the mechanisms of cell volume regulation are not unique to the brain and share many commonalities with other tissues. However, because ions and some organic osmolytes (e.g., major amino acid neurotransmitters) have a strong impact on neuronal excitability, cell volume regulation in the brain is a surprisingly treacherous process, which may cause more harm than good. This topical review covers the established and emerging information in this rapidly developing area of physiology.
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Affiliation(s)
- Corinne S Wilson
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Alexander A Mongin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Biophysics and Functional Diagnostics, Siberian State Medical University, Tomsk, Russian Federation
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25
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Formaggio F, Saracino E, Mola MG, Rao SB, Amiry-Moghaddam M, Muccini M, Zamboni R, Nicchia GP, Caprini M, Benfenati V. LRRC8A is essential for swelling-activated chloride current and for regulatory volume decrease in astrocytes. FASEB J 2018; 33:101-113. [PMID: 29957062 DOI: 10.1096/fj.201701397rr] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Consolidated evidence indicates that astroglial cells are critical in the homeostatic regulation of cellular volume by means of ion channels and aquaporin-4. Volume-regulated anion channel (VRAC) is the chloride channel that is activated upon cell swelling and critically contributes to cell volume regulation in astrocytes. The molecular identity of VRAC has been recently defined, revealing that it belongs to the leucine-rich repeat-containing 8 (LRRC8) protein family. However, there is a lack of evidence demonstrating that LRRC8A underpins VRAC currents in astrocyte. Nonetheless, direct evidence of the role of LRRC8A in astrocytic regulatory volume decrease remains to be proved. Here, we aim to bridge this gap in knowledge by combining RNA interference specific for LRRC8A with patch-clamp analyses and a water-permeability assay. We demonstrated that LRRC8A molecular expression is essential for swelling-activated chloride current via VRAC in primary-cultured cortical astrocytes. The knockdown of LRRC8A with a specific short interference RNA abolished the recovery of the cell volume after swelling induced by hypotonic challenge. In addition, immunoblotting, immunofluorescence, confocal imaging, and immunogold electron microscopy demonstrated that LRRC8A is expressed in the plasma membrane of primary cortical astrocytes and in situ in astrocytes at the perivascular interface with endothelial cells. Collectively, our results suggest that LRRC8A is an essential subunit of VRAC and a key factor for astroglial volume homeostasis.-Formaggio, F., Saracino, E., Mola, M. G., Rao, S. B., Amiry-Moghaddam, M., Muccini, M., Zamboni, R., Nicchia, G. P., Caprini, M., Benfenati, V. LRRC8A is essential for swelling-activated chloride current and for regulatory volume decrease in astrocytes.
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Affiliation(s)
- Francesco Formaggio
- Laboratory of Human and General Physiology, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.,Institute for the Study of Nanostructured Materials, National Research Council of Italy, Bologna, Italy
| | - Emanuela Saracino
- Institute for the Organic Synthesis and Photoreactivity, National Research Council of Italy, Bologna, Italy
| | - Maria Grazia Mola
- Department of Bioscience, Biotechnologies, and Biopharmaceutics, Centre of Excellence in Comparative Genomics, University of Bari Aldo Moro, Bari, Italy
| | - Shreyas Balachandra Rao
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Mahmood Amiry-Moghaddam
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Michele Muccini
- Institute for the Study of Nanostructured Materials, National Research Council of Italy, Bologna, Italy
| | - Roberto Zamboni
- Institute for the Organic Synthesis and Photoreactivity, National Research Council of Italy, Bologna, Italy
| | - Grazia Paola Nicchia
- Department of Bioscience, Biotechnologies, and Biopharmaceutics, Centre of Excellence in Comparative Genomics, University of Bari Aldo Moro, Bari, Italy.,Department of Neuroscience, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York, USA
| | - Marco Caprini
- Laboratory of Human and General Physiology, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.,Institute for the Study of Nanostructured Materials, National Research Council of Italy, Bologna, Italy
| | - Valentina Benfenati
- Institute for the Study of Nanostructured Materials, National Research Council of Italy, Bologna, Italy.,Institute for the Organic Synthesis and Photoreactivity, National Research Council of Italy, Bologna, Italy
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Lima AF, May G, Díaz-Colunga J, Pedreiro S, Paiva A, Ferreira L, Enver T, Iborra FJ, Pires das Neves R. Osmotic modulation of chromatin impacts on efficiency and kinetics of cell fate modulation. Sci Rep 2018; 8:7210. [PMID: 29740078 PMCID: PMC5940679 DOI: 10.1038/s41598-018-25517-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 04/12/2018] [Indexed: 11/23/2022] Open
Abstract
Chromatin structure is a major regulator of transcription and gene expression. Herein we explore the use of osmotic modulation to modify the chromatin structure and reprogram gene expression. In this study we use the extracellular osmotic pressure as a chromatin structure and transcriptional modulator. Hyposmotic modulation promotes chromatin loosening and induces changes in RNA polymerase II (Pol II) activity. The chromatin decondensation opens space for higher amounts of DNA engaged RNA Pol II. Hyposmotic modulation constitutes an alternative route to manipulate cell fate decisions. This technology was tested in model protocols of induced pluripotency and transdifferentiation in cells growing in suspension and adherent to substrates, CD34+ umbilical-cord-blood (UCB), fibroblasts and B-cells. The efficiency and kinetics of these cell fate modulation processes were improved by transient hyposmotic modulation of the cell environment.
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Affiliation(s)
- A F Lima
- UC-Biotech, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3060-197, Cantanhede, Portugal.,Faculty of Science and Technology, University Nova of Lisbon (MIT-Portugal PhD Program), 2829-516, Caparica, Portugal
| | - G May
- University College London, Gower Street, London, WC1E 6BT, UK
| | - J Díaz-Colunga
- Centro Nacional de Biotecnología, CSIC. Darwin 3, Campus de Cantoblanco, 28049, Madrid, Spain
| | - S Pedreiro
- Unidade de Gestão Operacional de Citometria, Centro Hospitalar e Universitário de Coimbra, 3000-075, Coimbra, Portugal
| | - A Paiva
- Unidade de Gestão Operacional de Citometria, Centro Hospitalar e Universitário de Coimbra, 3000-075, Coimbra, Portugal.,Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine,University of Coimbra, 3004-504, Coimbra, Portugal
| | - L Ferreira
- UC-Biotech, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3060-197, Cantanhede, Portugal.,Faculty of Medicine, University of Coimbra, 3004-504, Coimbra, Portugal
| | - T Enver
- University College London, Gower Street, London, WC1E 6BT, UK
| | - F J Iborra
- Centro Nacional de Biotecnología, CSIC. Darwin 3, Campus de Cantoblanco, 28049, Madrid, Spain
| | - R Pires das Neves
- UC-Biotech, CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3060-197, Cantanhede, Portugal. .,Institute for Interdisciplinary Research, University of Coimbra, 3030-789, Coimbra, Portugal.
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Effect of vasopressin-induced chronic hyponatremia on the regulation of the middle cerebral artery of the rat. Pflugers Arch 2018; 470:1047-1054. [PMID: 29550928 PMCID: PMC6013523 DOI: 10.1007/s00424-018-2141-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 10/29/2022]
Abstract
Vasopressin (arginine vasopressin, AVP) plays a crucial role in maintaining body fluid homeostasis. Excessive release of vasopressin can lead to hyponatremia. Changes in cerebral circulation during vasopressin-induced chronic hyponatremia are not elucidated. The present study has been designed to investigate the effect of chronic vasopressin-induced hyponatremia on the regulation of the tone of the middle cerebral artery (MCA) of the rat. Chronic hyponatremia was induced in vivo with the help of vasopressin, released continuously from subcutaneously implanted ALZET mini-osmotic pumps, and a liquid diet. After 3.5 days of chronic hyponatremia, the plasma Na+ concentration decreased to 119 ± 3 mM. MCAs were isolated and placed in a MOPS-buffered saline solution containing 121 mM Na+. Chronic hyponatremia did not affect the response of the MCA to increased intravascular pressure, to the administration of acetylcholine (ACh) and nitric oxide (NO) donor (SNAP, S-nitroso-N-acetyl-DL-penicillamine), and to increased K+ concentration, but impaired the response of the MCA to increased extravascular H+ concentration. Disturbed response of the MCA to acidosis was associated neither with the impairment of KATP channels nor with the activation of vasopressin V1 receptor. Correction of hyponatremia did not restore the response of the MCA to acidosis. These results indicate that cerebral blood vessels do not fully adapt to prolonged vasopressin-induced hyponatremia.
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AQP4e-Based Orthogonal Arrays Regulate Rapid Cell Volume Changes in Astrocytes. J Neurosci 2017; 37:10748-10756. [PMID: 28978666 DOI: 10.1523/jneurosci.0776-17.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/31/2017] [Accepted: 09/23/2017] [Indexed: 01/28/2023] Open
Abstract
Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the brain. It is predominantly expressed in astrocytes at the blood-brain and blood-liquor interfaces. Although several AQP4 isoforms have been identified in the mammalian brain, two, AQP4a (M1) and AQP4c (M23), have been confirmed to cluster into plasma membrane supramolecular structures, termed orthogonal arrays of particles (OAPs) and to enhance water transport through the plasma membrane. However, the role of the newly described water-conductive mammalian isoform AQP4e is unknown. Here, the dynamics of AQP4e aggregation into OAPs and its role in the regulation of astrocyte water homeostasis have been studied. Using super-resolution structured illumination, atomic force, and confocal microscopies, the results revealed that, in female rat astrocytes, AQP4e isoform colocalizes with OAPs, affecting its structural dynamics. In hypoosmotic conditions, which elicit cell edema, OAP formation was considerably enhanced by overexpressed AQP4e. Moreover, the kinetics of the cell swelling and of the regulatory volume decrease was faster in astrocytes overexpressing AQP4e compared with untransfected controls. Furthermore, the increase in maximal cell volume elicited by hypoosmotic stimulation was significantly smaller in AQP4e-overexpressing astrocytes. For the first time, this study demonstrates an active role of AQP4e in the regulation of OAP structural dynamics and in water homeostasis.SIGNIFICANCE STATEMENT Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the brain. To date, only AQP4a and AQP4c isoforms have been confirmed to enhance water transport through plasmalemma and to cluster into orthogonal arrays of particles (OAPs). We here studied the dynamics, aggregation, and role in the regulation of astrocyte water homeostasis of the newly described water-conductive mammalian isoform AQP4e. Our main findings are as follows: brain edema mimicking hypoosmotic conditions stimulates the formation of new OAPs with larger diameters, due to the incorporation of additional cytoplasmic AQP4 channels and the redistribution of AQP4 channels of the existing OAPs; and AQP4e affects the dynamics of cell swelling and regulatory volume decrease in astrocytes exposed to hypoosmotic conditions.
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29
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Kang S, Badea A, Rubakhin SS, Sweedler JV, Rogers JA, Nuzzo RG. Quantitative Reflection Imaging for the Morphology and Dynamics of Live Aplysia californica Pedal Ganglion Neurons Cultured on Nanostructured Plasmonic Crystals. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:8640-8650. [PMID: 28235182 PMCID: PMC5585034 DOI: 10.1021/acs.langmuir.6b04454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We describe a reflection imaging system that consists of a plasmonic crystal, a common laboratory microscope, and band-pass filters for use in the quantitative imaging and in situ monitoring of live cells and their substrate interactions. Surface plasmon resonance (SPR) provides a highly sensitive method to monitor changes in physicochemical properties occurring at metal-dielectric interfaces. Polyelectrolyte thin films deposited using the layer-by-layer (LBL) self-assembly method provide a reference system for calibrating the reflection contrast changes that occur when the polyelectrolyte film thickness changes and provide insight into the optical responses that originate from the multiple plasmonic features supported by this imaging system. Finite-difference time-domain (FDTD) simulations of the optical responses measured experimentally from the polyelectrolyte reference system are used to provide a calibration of the optical system for subsequent use in quantitative studies investigating live cell dynamics in cultures supported on a plasmonic crystal substrate. Live Aplysia californica pedal ganglion neurons cultured in artificial seawater were used as a model system through which to explore the utility of this plasmonic imaging technique. Here, the morphology of cellular peripheral structures ≲80 nm in thickness were quantitatively analyzed, and the dynamics of their trypsin-induced surface detachment were visualized. These results illustrate the capacities of this system for use in investigations of the dynamics of ultrathin cellular structures within complex bioanalytical environments.
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Affiliation(s)
- Somi Kang
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
| | - Adina Badea
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
| | - Stanislav S. Rubakhin
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
| | - Jonathan V. Sweedler
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
| | - John A. Rogers
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
| | - Ralph G. Nuzzo
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States of America
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30
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Hyponatremia and the Brain. Kidney Int Rep 2017; 3:24-35. [PMID: 29340311 PMCID: PMC5762960 DOI: 10.1016/j.ekir.2017.08.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/23/2017] [Accepted: 08/28/2017] [Indexed: 01/12/2023] Open
Abstract
Hyponatremia is defined by low serum sodium concentration and is the most common electrolyte disorder encountered in clinical practice. Serum sodium is the main determinant of plasma osmolality, which, in turn, affects cell volume. In the presence of low extracellular osmolality, cells will swell if the adaptation mechanisms involved in the cell volume maintenance are inadequate. The most dramatic effects of hyponatremia on the brain are seen when serum sodium concentration decreases in a short period, allowing little or no adaptation. The brain is constrained inside a nonextensible envelope; thus, brain swelling carries a significant morbidity because of the compression of brain parenchyma over the rigid skull. Serum sodium concentration is an important determinant of several biological pathways in the nervous system, and recent studies have suggested that hyponatremia carries a significant risk of neurological impairment even in the absence of brain edema. The brain can also be affected by the treatment of hyponatremia, which, if not undertaken cautiously, could lead to osmotic demyelination syndrome, a rare demyelinating brain disorder that occurs after rapid correction of severe hyponatremia. This review summarizes the pathophysiology of brain complications of hyponatremia and its treatment.
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31
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Takahashi N, Omi A, Uchino H, Kudo Y. Different characteristics of cell volume and intracellular calcium ion concentration dynamics between the hippocampal CA1 and lateral cerebral cortex of male mouse brain slices during exposure to hypotonic stress. J Neurosci Res 2017; 96:117-127. [DOI: 10.1002/jnr.24086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/11/2017] [Accepted: 05/04/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Nanae Takahashi
- Department of Anesthesiology; Tokyo Medical University Hachioji Medical Center; 1163 Tatemachi, Hachioji Tokyo 193-0998 Japan
| | - Akibumi Omi
- Department of Anesthesiology; Tokyo Medical University Hachioji Medical Center; 1163 Tatemachi, Hachioji Tokyo 193-0998 Japan
| | - Hiroyuki Uchino
- Depatment of Anesthesiology; Tokyo Medical University; 6-7-1 Nishishinjuku, Shinjuku Tokyo 160-0023 Japan
| | - Yoshihisa Kudo
- Department of Anesthesiology; Tokyo Medical University Hachioji Medical Center; 1163 Tatemachi, Hachioji Tokyo 193-0998 Japan
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32
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Netti V, Fernández J, Kalstein M, Pizzoni A, Di Giusto G, Rivarola V, Ford P, Capurro C. TRPV4 Contributes to Resting Membrane Potential in Retinal Müller Cells: Implications in Cell Volume Regulation. J Cell Biochem 2017; 118:2302-2313. [PMID: 28098409 DOI: 10.1002/jcb.25884] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/13/2017] [Indexed: 11/10/2022]
Abstract
Neural activity alters osmotic gradients favoring cell swelling in retinal Müller cells. This swelling is followed by a regulatory volume decrease (RVD), partially mediated by an efflux of KCl and water. The transient receptor potential channel 4 (TRPV4), a nonselective calcium channel, has been proposed as a candidate for mediating intracellular Ca2+ elevation induced by swelling. We previously demonstrated in a human Müller cell line (MIO-M1) that RVD strongly depends on ion channel activation and, consequently, on membrane potential (Vm ). The aim of this study was to investigate if Ca2+ influx via TRPV4 contributes to RVD by modifying intracellular Ca2+ concentration and/or modulating Vm in MIO-M1 cells. Cell volume, intracellular Ca2+ levels, and Vm changes were evaluated using fluorescent probes. Results showed that MIO-M1 cells express functional TRPV4 which determines the resting Vm associated with K+ channels. Swelling-induced increases in Ca2+ levels was due to both Ca2+ release from intracellular stores and Ca2+ influx by a pathway alternative to TRPV4. TRPV4 blockage affected swelling-induced biphasic response (depolarization-repolarization), suggesting its participation in modulating Vm changes during RVD. Agonist stimulation of Ca2+ influx via TRPV4 activated K+ channels hyperpolarizing Vm and accelerating RVD. We propose that TRPV4 forms a signaling complex with Ca2+ and/or voltage-dependent K+ channels to define resting Vm and Vm changes during RVD. TRPV4 involvement in RVD depends on the type of stimuli and/or degree of channel activation, leading to a maximum RVD response when Ca2+ influx overcomes a threshold and activates further signaling pathways in cell volume regulation. J. Cell. Biochem. 118: 2302-2313, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Vanina Netti
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Juan Fernández
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Maia Kalstein
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro Pizzoni
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gisela Di Giusto
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Valeria Rivarola
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula Ford
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Claudia Capurro
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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Turning down the volume: Astrocyte volume change in the generation and termination of epileptic seizures. Neurobiol Dis 2017; 104:24-32. [PMID: 28438505 DOI: 10.1016/j.nbd.2017.04.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 12/20/2022] Open
Abstract
Approximately 1% of the global population suffers from epilepsy, a class of disorders characterized by recurrent and unpredictable seizures. Of these cases roughly one-third are refractory to current antiepileptic drugs, which typically target neuronal excitability directly. The events leading to seizure generation and epileptogenesis remain largely unknown, hindering development of new treatments. Some recent experimental models of epilepsy have provided compelling evidence that glial cells, especially astrocytes, could be central to seizure development. One of the proposed mechanisms for astrocyte involvement in seizures is astrocyte swelling, which may promote pathological neuronal firing and synchrony through reduction of the extracellular space and elevated glutamate concentrations. In this review, we discuss the common conditions under which astrocytes swell, the resultant effects on neural excitability, and how seizure development may ultimately be influenced by these effects.
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Abstract
The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.
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Affiliation(s)
- Rute Pereira
- Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal and Multidisciplinary Unit for Biomedical Research-UMIB, ICBAS-UP, Portugal
| | - Rosália Sá
- Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal and Multidisciplinary Unit for Biomedical Research-UMIB, ICBAS-UP, Portugal
| | - Alberto Barros
- Centre for Reproductive Genetics Alberto Barros, Av. do Bessa, 240, 1° Dto. Frente, 4100-012 Porto, Portugal.,Department of Genetics, Faculty of Medicine, University of Porto. Alameda Prof. Hernâni Monteiro, 4200-319 Porto, Portugal and Institute of Health Research an Innovation (I3S), University of Porto, Portugal
| | - Mário Sousa
- Department of Microscopy, Laboratory of Cell Biology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal and Multidisciplinary Unit for Biomedical Research-UMIB, ICBAS-UP, Portugal
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35
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Volume regulation of intestinal cells of echinoderms: Putative role of ion transporters (Na+/K+-ATPase and NKCC). Comp Biochem Physiol A Mol Integr Physiol 2016; 201:124-131. [DOI: 10.1016/j.cbpa.2016.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/01/2016] [Accepted: 07/08/2016] [Indexed: 11/24/2022]
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36
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Acetazolamide Mitigates Astrocyte Cellular Edema Following Mild Traumatic Brain Injury. Sci Rep 2016; 6:33330. [PMID: 27623738 PMCID: PMC5022024 DOI: 10.1038/srep33330] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 08/25/2016] [Indexed: 12/31/2022] Open
Abstract
Non-penetrating or mild traumatic brain injury (mTBI) is commonly experienced in accidents, the battlefield and in full-contact sports. Astrocyte cellular edema is one of the major factors that leads to high morbidity post-mTBI. Various studies have reported an upregulation of aquaporin-4 (AQP4), a water channel protein, following brain injury. AZA is an antiepileptic drug that has been shown to inhibit AQP4 expression and in this study we investigate the drug as a therapeutic to mitigate the extent of mTBI induced cellular edema. We hypothesized that mTBI-mediated astrocyte dysfunction, initiated by increased intracellular volume, could be reduced when treated with AZA. We tested our hypothesis in a three-dimensional in vitro astrocyte model of mTBI. Samples were subject to no stretch (control) or one high-speed stretch (mTBI) injury. AQP4 expression was significantly increased 24 hours after mTBI. mTBI resulted in a significant increase in the cell swelling within 30 min of mTBI, which was significantly reduced in the presence of AZA. Cell death and expression of S100B was significantly reduced when AZA was added shortly before mTBI stretch. Overall, our data point to occurrence of astrocyte swelling immediately following mTBI, and AZA as a promising treatment to mitigate downstream cellular mortality.
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37
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Ullrich F, Reincke SM, Voss FK, Stauber T, Jentsch TJ. Inactivation and Anion Selectivity of Volume-regulated Anion Channels (VRACs) Depend on C-terminal Residues of the First Extracellular Loop. J Biol Chem 2016; 291:17040-8. [PMID: 27325695 DOI: 10.1074/jbc.m116.739342] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Indexed: 11/06/2022] Open
Abstract
Canonical volume-regulated anion channels (VRACs) are crucial for cell volume regulation and have many other important roles, including tumor drug resistance and release of neurotransmitters. Although VRAC-mediated swelling-activated chloride currents (ICl,vol) have been studied for decades, exploration of the structure-function relationship of VRAC has become possible only after the recent discovery that VRACs are formed by differently composed heteromers of LRRC8 proteins. Inactivation of ICl,vol at positive potentials, a typical hallmark of VRACs, strongly varies between native cell types. Exploiting the large differences in inactivation between different LRRC8 heteromers, we now used chimeras assembled from isoforms LRRC8C and LRRC8E to uncover a highly conserved extracellular region preceding the second LRRC8 transmembrane domain as a major determinant of ICl,vol inactivation. Point mutations identified two amino acids (Lys-98 and Asp-100 in LRRC8A and equivalent residues in LRRC8C and -E), which upon charge reversal strongly altered the kinetics and voltage dependence of inactivation. Importantly, charge reversal at the first position also reduced the iodide > chloride permeability of ICl,vol This change in selectivity was stronger when both the obligatory LRRC8A subunit and the other co-expressed isoform (LRR8C or -E) carried such mutations. Hence, the C-terminal part of the first extracellular loop not only determines VRAC inactivation but might also participate in forming its outer pore. Inactivation of VRACs may involve a closure of the extracellular mouth of the permeation pathway.
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Affiliation(s)
- Florian Ullrich
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, the Graduate Program, Freie Universität Berlin, D-14195 Berlin, and
| | - S Momsen Reincke
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Felizia K Voss
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Tobias Stauber
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin
| | - Thomas J Jentsch
- From the Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, Neurocure, Charité Universitätsmedizin, D-10117 Berlin, Germany
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Zhou X, Naguro I, Ichijo H, Watanabe K. Mitogen-activated protein kinases as key players in osmotic stress signaling. Biochim Biophys Acta Gen Subj 2016; 1860:2037-52. [PMID: 27261090 DOI: 10.1016/j.bbagen.2016.05.032] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/21/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Osmotic stress arises from the difference between intracellular and extracellular osmolality. It induces cell swelling or shrinkage as a consequence of water influx or efflux, which threatens cellular activities. Mitogen-activated protein kinases (MAPKs) play central roles in signaling pathways in osmotic stress responses, including the regulation of intracellular levels of inorganic ions and organic osmolytes. SCOPE OF REVIEW The present review summarizes the cellular osmotic stress response and the function and regulation of the vertebrate MAPK signaling pathways involved. We also describe recent findings regarding apoptosis signal-regulating kinase 3 (ASK3), a MAP3K member, to demonstrate its regulatory effects on signaling molecules beyond MAPKs. MAJOR CONCLUSIONS MAPKs are rapidly activated by osmotic stress and have diverse roles, such as cell volume regulation, gene expression, and cell survival/death. There is significant cell type specificity in the function and regulation of MAPKs. Based on its activity change during osmotic stress and its regulation of the WNK1-SPAK/OSR1 pathway, ASK3 is expected to play important roles in osmosensing mechanisms and cellular functions related to osmoregulation. GENERAL SIGNIFICANCE MAPKs are essential for various cellular responses to osmotic stress; thus, the identification of the upstream regulators of MAPK pathways will provide valuable clues regarding the cellular osmosensing mechanism, which remains elusive in mammals. The elucidation of in vivo MAPK functions is also important because osmotic stress in physiological and pathophysiological conditions often results from changes in the intracellular osmolality. These studies potentially contribute to the establishment of therapeutic strategies against diseases that accompany osmotic perturbation.
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Affiliation(s)
- Xiangyu Zhou
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Isao Naguro
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hidenori Ichijo
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kengo Watanabe
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Jo AO, Ryskamp DA, Phuong TTT, Verkman AS, Yarishkin O, MacAulay N, Križaj D. TRPV4 and AQP4 Channels Synergistically Regulate Cell Volume and Calcium Homeostasis in Retinal Müller Glia. J Neurosci 2015; 35:13525-37. [PMID: 26424896 PMCID: PMC4588615 DOI: 10.1523/jneurosci.1987-15.2015] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 11/21/2022] Open
Abstract
Brain edema formation occurs after dysfunctional control of extracellular volume partly through impaired astrocytic ion and water transport. Here, we show that such processes might involve synergistic cooperation between the glial water channel aquaporin 4 (AQP4) and the transient receptor potential isoform 4 (TRPV4), a polymodal swelling-sensitive cation channel. In mouse retinas, TRPV4 colocalized with AQP4 in the end feet and radial processes of Müller astroglia. Genetic ablation of TRPV4 did not affect the distribution of AQP4 and vice versa. However, retinas from Trpv4(-/-) and Aqp4(-/-) mice exhibited suppressed transcription of genes encoding Trpv4, Aqp4, and the Kir4.1 subunit of inwardly rectifying potassium channels. Swelling and [Ca(2+)]i elevations evoked in Müller cells by hypotonic stimulation were antagonized by the selective TRPV4 antagonist HC-067047 (2-methyl-1-[3-(4-morpholinyl)propyl]-5-phenyl-N-[3-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide) or Trpv4 ablation. Elimination of Aqp4 suppressed swelling-induced [Ca(2+)]i elevations but only modestly attenuated the amplitude of Ca(2+) signals evoked by the TRPV4 agonist GSK1016790A [(N-((1S)-1-{[4-((2S)-2-{[(2,4-dichlorophenyl)sulfonyl]amino}-3-hydroxypropanoyl)-1-piperazinyl]carbonyl}-3-methylbutyl)-1-benzothiophene-2-carboxamide]. Glial cells lacking TRPV4 but not AQP4 showed deficits in hypotonic swelling and regulatory volume decrease. Functional synergy between TRPV4 and AQP4 during cell swelling was confirmed in the heterologously expressing Xenopus oocyte model. Importantly, when the swelling rate was osmotically matched for AQP4-positive and AQP4-negative oocytes, TRPV4 activation became independent of AQP4. We conclude that AQP4-mediated water fluxes promote the activation of the swelling sensor, whereas Ca(2+) entry through TRPV4 channels reciprocally modulates volume regulation, swelling, and Aqp4 gene expression. Therefore, TRPV4-AQP4 interactions constitute a molecular system that fine-tunes astroglial volume regulation by integrating osmosensing, calcium signaling, and water transport and, when overactivated, triggers pathological swelling. Significance statement: We characterize the physiological features of interactions between the astroglial swelling sensor transient receptor potential isoform 4 (TRPV4) and the aquaporin 4 (AQP4) water channel in retinal Müller cells. Our data reveal an elegant and complex set of mechanisms involving reciprocal interactions at the level of glial gene expression, calcium homeostasis, swelling, and volume regulation. Specifically, water influx through AQP4 drives calcium influx via TRPV4 in the glial end foot, which regulates expression of Aqp4 and Kir4.1 genes and facilitates the time course and amplitude of hypotonicity-induced swelling and regulatory volume decrease. We confirm the crucial facets of the signaling mechanism in heterologously expressing oocytes. These results identify the molecular mechanism that contributes to dynamic regulation of glial volume but also provide new insights into the pathophysiology of glial reactivity and edema formation.
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Affiliation(s)
- Andrew O Jo
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Daniel A Ryskamp
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute, Interdepartmental Program in Neuroscience, and
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Alan S Verkman
- Department of Medicine, University of California San Francisco, San Francisco, California 94143, and
| | - Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute
| | - Nanna MacAulay
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, Moran Eye Institute, Interdepartmental Program in Neuroscience, and Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah 84132,
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Laville M, Burst V, Peri A, Verbalis JG. Hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH): therapeutic decision-making in real-life cases. Clin Kidney J 2015; 6:i1-i20. [PMID: 26069838 PMCID: PMC4438352 DOI: 10.1093/ckj/sft113] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Despite being the most common electrolyte disturbance encountered in clinical practice, the diagnosis and treatment of hyponatremia (defined as a serum sodium concentration <135 mmol/L) remains far from optimal. This is extremely troubling because not only is hyponatremia associated with increased morbidity, length of hospital stay and hospital resource use, but it has also been shown to be associated with increased mortality. The reasons for this poor management may partly lie in the heterogeneous nature of the disorder; hyponatremia presents with a variety of possible etiologies, differing symptomology and fluid volume status, thereby making its diagnosis potentially complex. In addition, a general lack of awareness of the clinical impact of the disorder, a fear of adverse outcomes through overcorrection of sodium levels, and a lack of effective targeted treatments until recent years, may all have contributed to a reticence to actively treat cases of hyponatremia. There is therefore a clear unmet need to further educate physicians on the pathophysiology, diagnosis and management of this important condition. Through the use of a variety of real-world cases of patients with hyponatremia secondary to the syndrome of inappropriate secretion of antidiuretic hormone—a condition that accounts for approximately one-third of all cases of hyponatremia—this supplement aims to provide a comprehensive overview of the challenges faced in diagnosing and managing hyponatremia. These cases will also help to illustrate how some of the limitations of traditional therapies may be overcome with the use of vasopressin receptor antagonists.
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Affiliation(s)
- Maurice Laville
- Renal Unit , Lyon-Sud Hospital , Pierre-Bénite 69495 , France ; INSERM U1060, CarMeN Institute , University of Lyon , Lyon , France
| | - Volker Burst
- Department 2 of Internal Medicine and Center for Molecular Medicine Cologne , University of Cologne , Cologne , Germany
| | - Alessandro Peri
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences , University of Florence , Florence , Italy
| | - Joseph G Verbalis
- Division of Endocrinology and Metabolism, Department of Medicine , Georgetown University Medical Center , Washington, DC 20007 , USA
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Andronic J, Shirakashi R, Pickel SU, Westerling KM, Klein T, Holm T, Sauer M, Sukhorukov VL. Hypotonic activation of the myo-inositol transporter SLC5A3 in HEK293 cells probed by cell volumetry, confocal and super-resolution microscopy. PLoS One 2015; 10:e0119990. [PMID: 25756525 PMCID: PMC4355067 DOI: 10.1371/journal.pone.0119990] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 01/21/2015] [Indexed: 11/19/2022] Open
Abstract
Swelling-activated pathways for myo-inositol, one of the most abundant organic osmolytes in mammalian cells, have not yet been identified. The present study explores the SLC5A3 protein as a possible transporter of myo-inositol in hyponically swollen HEK293 cells. To address this issue, we examined the relationship between the hypotonicity-induced changes in plasma membrane permeability to myo-inositol Pino [m/s] and expression/localization of SLC5A3. Pino values were determined by cell volumetry over a wide tonicity range (100–275 mOsm) in myo-inositol-substituted solutions. While being negligible under mild hypotonicity (200–275 mOsm), Pino grew rapidly at osmolalities below 200 mOsm to reach a maximum of ∼3 nm/s at 100–125 mOsm, as indicated by fast cell swelling due to myo-inositol influx. The increase in Pino resulted most likely from the hypotonicity-mediated incorporation of cytosolic SLC5A3 into the plasma membrane, as revealed by confocal fluorescence microscopy of cells expressing EGFP-tagged SLC5A3 and super-resolution imaging of immunostained SLC5A3 by direct stochastic optical reconstruction microscopy (dSTORM). dSTORM in hypotonic cells revealed a surface density of membrane-associated SLC5A3 proteins of 200–2000 localizations/μm2. Assuming SLC5A3 to be the major path for myo-inositol, a turnover rate of 80–800 myo-inositol molecules per second for a single transporter protein was estimated from combined volumetric and dSTORM data. Hypotonic stress also caused a significant upregulation of SLC5A3 gene expression as detected by semiquantitative RT-PCR and Western blot analysis. In summary, our data provide first evidence for swelling-mediated activation of SLC5A3 thus suggesting a functional role of this transporter in hypotonic volume regulation of mammalian cells.
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Affiliation(s)
- Joseph Andronic
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Ryo Shirakashi
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan
| | - Simone U. Pickel
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Katherine M. Westerling
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Teresa Klein
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Thorge Holm
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
| | - Vladimir L. Sukhorukov
- Department of Biotechnology and Biophysics, University of Würzburg, Biozentrum, Am Hubland, Würzburg, Germany
- * E-mail:
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Vascular adaptation to aerobic exercise: A new experimental approach. Sci Sports 2015. [DOI: 10.1016/j.scispo.2014.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Brennan RS, Galvez F, Whitehead A. Reciprocal osmotic challenges reveal mechanisms of divergence in phenotypic plasticity in the killifish Fundulus heteroclitus. J Exp Biol 2015; 218:1212-22. [DOI: 10.1242/jeb.110445] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 02/16/2015] [Indexed: 12/12/2022]
Abstract
The killifish Fundulus heteroclitus is an estuarine species with broad physiological plasticity enabling acclimation to diverse stressors. Previous work suggests freshwater populations expanded their physiology to accommodate low salinity environments, however, it is unknown if this compromises their tolerance to high salinity. We employed a comparative approach to investigate the mechanisms of a derived freshwater phenotype and the fate of an ancestral euryhaline phenotype after invasion of a freshwater environment. We compared physiological and transcriptomic responses to high and low salinity stress in fresh and brackish water populations and found an enhanced plasticity to low salinity in the freshwater population coupled with a reduced ability to acclimate to high salinity. Transcriptomic data identified genes with a conserved common response, a conserved salinity dependent response, and responses associated with population divergence. Conserved common acclimation responses revealed stress responses and alterations in cell-cycle regulation as important mechanisms in the general osmotic response. Salinity-specific responses included the regulation of genes involved in ion transport, intracellular calcium, energetic processes, and cellular remodeling. Genes diverged between populations were primarily those showing salinity-specific expression and included those regulating polyamine homeostasis and cell cycle. Additionally, when populations were matched with their native salinity, expression patterns were consistent with the concept of “transcriptomic resilience,” suggesting local adaptation. These findings provide insight into the fate of a plastic phenotype after a shift in environmental salinity and help to reveal mechanisms allowing for euryhalinity.
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Affiliation(s)
- Reid S. Brennan
- Department of Environmental Toxicology, University of California-Davis, California, 95616, USA
| | - Fernando Galvez
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Andrew Whitehead
- Department of Environmental Toxicology, University of California-Davis, California, 95616, USA
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Voss FK, Ullrich F, Münch J, Lazarow K, Lutter D, Mah N, Andrade-Navarro MA, von Kries JP, Stauber T, Jentsch TJ. Identification of LRRC8 heteromers as an essential component of the volume-regulated anion channel VRAC. Science 2014; 344:634-8. [PMID: 24790029 DOI: 10.1126/science.1252826] [Citation(s) in RCA: 442] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Regulation of cell volume is critical for many cellular and organismal functions, yet the molecular identity of a key player, the volume-regulated anion channel VRAC, has remained unknown. A genome-wide small interfering RNA screen in mammalian cells identified LRRC8A as a VRAC component. LRRC8A formed heteromers with other LRRC8 multispan membrane proteins. Genomic disruption of LRRC8A ablated VRAC currents. Cells with disruption of all five LRRC8 genes required LRRC8A cotransfection with other LRRC8 isoforms to reconstitute VRAC currents. The isoform combination determined VRAC inactivation kinetics. Taurine flux and regulatory volume decrease also depended on LRRC8 proteins. Our work shows that VRAC defines a class of anion channels, suggests that VRAC is identical to the volume-sensitive organic osmolyte/anion channel VSOAC, and explains the heterogeneity of native VRAC currents.
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Affiliation(s)
- Felizia K Voss
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin
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Talaei S, Fujii Y, Truffer F, van der Wal PD, de Rooij NF. Forward osmosis in a portable device for automatic osmolality adjustment of environmental water samples evaluated by cell-based biosensors. J Memb Sci 2014. [DOI: 10.1016/j.memsci.2013.12.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nagelhus EA, Amiry-Moghaddam M, Bergersen LH, Bjaalie JG, Eriksson J, Gundersen V, Leergaard TB, Morth JP, Storm-Mathisen J, Torp R, Walhovd KB, Tønjum T. The glia doctrine: addressing the role of glial cells in healthy brain ageing. Mech Ageing Dev 2013; 134:449-59. [PMID: 24141107 DOI: 10.1016/j.mad.2013.10.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/03/2013] [Accepted: 10/04/2013] [Indexed: 01/14/2023]
Abstract
Glial cells in their plurality pervade the human brain and impact on brain structure and function. A principal component of the emerging glial doctrine is the hypothesis that astrocytes, the most abundant type of glial cells, trigger major molecular processes leading to brain ageing. Astrocyte biology has been examined using molecular, biochemical and structural methods, as well as 3D brain imaging in live animals and humans. Exosomes are extracelluar membrane vesicles that facilitate communication between glia, and have significant potential for biomarker discovery and drug delivery. Polymorphisms in DNA repair genes may indirectly influence the structure and function of membrane proteins expressed in glial cells and predispose specific cell subgroups to degeneration. Physical exercise may reduce or retard age-related brain deterioration by a mechanism involving neuro-glial processes. It is most likely that additional information about the distribution, structure and function of glial cells will yield novel insight into human brain ageing. Systematic studies of glia and their functions are expected to eventually lead to earlier detection of ageing-related brain dysfunction and to interventions that could delay, reduce or prevent brain dysfunction.
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Affiliation(s)
- Erlend A Nagelhus
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Norway; Centre for Molecular Medicine Norway (NCMM), The Nordic EMBL Partnership, University of Oslo, Norway; Department of Neurology, Oslo University Hospital, Norway
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Verbalis JG, Goldsmith SR, Greenberg A, Korzelius C, Schrier RW, Sterns RH, Thompson CJ. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am J Med 2013; 126:S1-42. [PMID: 24074529 DOI: 10.1016/j.amjmed.2013.07.006] [Citation(s) in RCA: 603] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hyponatremia is a serious, but often overlooked, electrolyte imbalance that has been independently associated with a wide range of deleterious changes involving many different body systems. Untreated acute hyponatremia can cause substantial morbidity and mortality as a result of osmotically induced cerebral edema, and excessively rapid correction of chronic hyponatremia can cause severe neurologic impairment and death as a result of osmotic demyelination. The diverse etiologies and comorbidities associated with hyponatremia pose substantial challenges in managing this disorder. In 2007, a panel of experts in hyponatremia convened to develop the Hyponatremia Treatment Guidelines 2007: Expert Panel Recommendations that defined strategies for clinicians caring for patients with hyponatremia. In the 6 years since the publication of that document, the field has seen several notable developments, including new evidence on morbidities and complications associated with hyponatremia, the importance of treating mild to moderate hyponatremia, and the efficacy and safety of vasopressin receptor antagonist therapy for hyponatremic patients. Therefore, additional guidance was deemed necessary and a panel of hyponatremia experts (which included all of the original panel members) was convened to update the previous recommendations for optimal current management of this disorder. The updated expert panel recommendations in this document represent recommended approaches for multiple etiologies of hyponatremia that are based on both consensus opinions of experts in hyponatremia and the most recent published data in this field.
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Petrini S, Minnone G, Coccetti M, Frank C, Aiello C, Cutarelli A, Ambrosini E, Lanciotti A, Brignone MS, D'Oria V, Strippoli R, De Benedetti F, Bertini E, Bracci-Laudiero L. Monocytes and macrophages as biomarkers for the diagnosis of megalencephalic leukoencephalopathy with subcortical cysts. Mol Cell Neurosci 2013; 56:307-21. [DOI: 10.1016/j.mcn.2013.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 06/05/2013] [Accepted: 07/02/2013] [Indexed: 12/20/2022] Open
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Minieri L, Pivonkova H, Caprini M, Harantova L, Anderova M, Ferroni S. The inhibitor of volume-regulated anion channels DCPIB activates TREK potassium channels in cultured astrocytes. Br J Pharmacol 2013; 168:1240-54. [PMID: 23072356 DOI: 10.1111/bph.12011] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/10/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The ethacrynic acid derivative, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) is considered to be a specific and potent inhibitor of volume-regulated anion channels (VRACs). In the CNS, DCPIB was shown to be neuroprotective through mechanisms principally associated to its action on VRACs. We hypothesized that DCPIB could also regulate the activity of other astroglial channels involved in cell volume homeostasis. EXPERIMENTAL APPROACH Experiments were performed in rat cortical astrocytes in primary culture and in hippocampal astrocytes in situ. The effect of DCPIB was evaluated by patch-clamp electrophysiology and immunocytochemical techniques. Results were verified by comparative analysis with recombinant channels expressed in COS-7 cells. KEY RESULTS In cultured astrocytes, DCPIB promoted the activation of a K(+) conductance mediated by two-pore-domain K(+) (K(2P) ) channels. The DCPIB effect occluded that of arachidonic acid, which activates K(2P) channels K(2P) 2.1 (TREK-1) and K(2P) 10.1 (TREK-2) in cultured astrocytes. Immunocytochemical analysis suggests that cultured astrocytes express K(2P) 2.1 and K(2P) 10.1 proteins. Moreover, DCPIB opened recombinant K(2P) 2.1 and K(2P) 10.1 expressed in heterologous system. In brain slices, DCPIB did not augment the large background K(+) conductance in hippocampal astrocytes, but caused an increment in basal K(+) current of neurons. CONCLUSION AND IMPLICATIONS Our results indicate that the neuroprotective effect of DCPIB could be due, at least in part, to activation of TREK channels. DCPIB could be used as template to build new pharmacological tools able to increase background K(+) conductance in astroglia and neuronal cells.
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Affiliation(s)
- L Minieri
- Department of Human and General Physiology, University of Bologna, Bologna, Italy
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50
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Wu J, Yang H, Peng Y, Fang L, Zheng W, Song Z. The role of local field potential coupling in epileptic synchronization. Neural Regen Res 2013; 8:745-53. [PMID: 25206721 PMCID: PMC4146071 DOI: 10.3969/j.issn.1673-5374.2013.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 01/25/2013] [Indexed: 11/18/2022] Open
Abstract
THIS REVIEW HOPES TO CLEARLY EXPLAIN THE FOLLOWING VIEWPOINTS (1) Neuronal synchronization underlies brain functioning, and it seems possible that blocking excessive synchronization in an epileptic neural network could reduce or even control seizures. (2) Local field potential coupling is a very common phenomenon during synchronization in networks. Removal of neurons or neuronal networks that are coupled can significantly alter the extracellular field potential. Interventions of coupling mediated by local field potentials could result in desynchronization of epileptic seizures. (3) The synchronized electrical activity generated by neurons is sensitive to changes in the size of the extracellular space, which affects the efficiency of field potential transmission and the threshold of cell excitability. (4) Manipulations of the field potential fluctuations could help block synchronization at seizure onset.
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Affiliation(s)
- Jiongxing Wu
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Heng Yang
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Yufeng Peng
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Liangjuan Fang
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Wen Zheng
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
| | - Zhi Song
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha 410013, Hunan Province, China
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