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Boscia F, Begum G, Pignataro G, Sirabella R, Cuomo O, Casamassa A, Sun D, Annunziato L. Glial Na(+) -dependent ion transporters in pathophysiological conditions. Glia 2016; 64:1677-97. [PMID: 27458821 DOI: 10.1002/glia.23030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/22/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh Medical School
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Rossana Sirabella
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Ornella Cuomo
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania, 15213
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
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Rummer JL, Brauner CJ. Plasma-accessible carbonic anhydrase at the tissue of a teleost fish may greatly enhance oxygen delivery: in vitro evidence in rainbow trout, Oncorhynchus mykiss. J Exp Biol 2011; 214:2319-28. [PMID: 21697423 DOI: 10.1242/jeb.054049] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
SUMMARY
During a generalized acidosis in rainbow trout, catecholamines are released into the blood, activating red blood cell (RBC) Na+/H+ exchange (βNHE), thus protecting RBC intracellular pH (pHi) and subsequent O2 binding at the gill. Because of the presence of a Root effect (a reduction in oxygen carrying capacity of the blood with a reduction in pH), the latter could otherwise be impaired. However, plasma-accessible carbonic anhydrase (CA) at the tissues (and absence at the gills) may result in selective short-circuiting of RBC βNHE pH regulation. This would acidify the RBCs and greatly enhance O2 delivery by exploitation of the combined Bohr-Root effect, a mechanism not previously proposed. As proof-of-principle, an in vitro closed system was developed to continuously monitor extracellular pH (pHe) and O2 tension (PO2) of rainbow trout blood. In this closed system, adding CA to acidified, adrenergically stimulated RBCs short-circuited βNHE pH regulation, resulting in an increase in PO2 by >30 mmHg, depending on the starting Hb-O2 saturation and degree of initial acidification. Interestingly, in the absence of adrenergic stimulation, addition of CA still elevated PO2, albeit to a lesser extent, a response that was absent during general NHE inhibition. If plasma-accessible CA-mediated short-circuiting is operational in vivo, the combined Bohr-Root effect system unique to teleost fishes could markedly enhance tissue O2 delivery far in excess of that in vertebrates possessing a Bohr effect alone and may lead to insights about the early evolution of the Root effect.
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Affiliation(s)
- Jodie L. Rummer
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada
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Rummer JL, Roshan-Moniri M, Balfry SK, Brauner CJ. Use it or lose it? Sablefish, Anoplopoma fimbria, a species representing a fifth teleostean group where the βNHE associated with the red blood cell adrenergic stress response has been secondarily lost. J Exp Biol 2010; 213:1503-12. [DOI: 10.1242/jeb.038844] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Like most teleosts, sablefish (Anoplopoma fimbria Pallas 1814) blood exhibits a moderate Root effect (~35% maximal desaturation), where a reduction in blood pH dramatically reduces O2 carrying capacity, a mechanism important for oxygenating the eye and filling the swim bladder (SB) in teleosts. Although sablefish lack a SB, we observed a well-defined choroid rete at the eye. The adrenergically mediated cell swelling typically associated with a functional red blood cell (RBC) β-adrenergic Na+/H+ exchanger (βNHE), which would normally protect RBC pH, and thus O2 transport, during a generalized acidosis, was not observed in sablefish blood. Neither isoproterenol (a β-agonist) nor 8-bromo cAMP could elicit this response. Furthermore, RBC osmotic shrinkage, known to stimulate NHEs in general and βNHE in other teleosts such as trout and flounder, resulted in no significant regulatory volume increase (RVI), further supporting the absence of a functional RBC βNHE. The onset of the Root effect occurs at a much lower RBC pH (6.83–6.92) than in other teleosts, and thus RBC βNHE may not be required to protect O2 transport during a generalized acidosis in vivo. Phylogenetically, sablefish may represent a fifth group of teleosts exhibiting a secondary reduction or loss of βNHE activity. However, sablefish have not lost the choroid rete at the eye (unlike in the other four groups), which may still function with the Root effect to oxygenate the retina, but the low pH onset of the Root effect may ensure haemoglobin (Hb)-O2 binding is not compromised at the respiratory surface during a general acidosis in the absence of RBC βNHE. The sablefish may represent an anomaly within the framework of Root effect evolution, in that they possess a moderate Root effect and a choroid rete at the eye, but lack the RBC βNHE and the SB system.
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Affiliation(s)
- Jodie L. Rummer
- Department of Zoology, University of British Columbia, No. 2370–6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4
| | - Mani Roshan-Moniri
- Department of Zoology, University of British Columbia, No. 2370–6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4
| | - Shannon K. Balfry
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Colin J. Brauner
- Department of Zoology, University of British Columbia, No. 2370–6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4
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Abstract
The present contribution reviews current knowledge of apparently oxygen-dependent ion transport in erythrocytes and presents modern hypotheses on their regulatory mechanisms and physiological roles. In addition to molecular oxygen as such, reactive oxygen species, nitric oxide, carbon monoxide, regional variations of cellular ATP and hydrogen sulphide may play a role in the regulation of transport, provided that they are affected by oxygen tension. It appears that the transporter molecules themselves do not have direct oxygen sensors. Thus, the oxygen level must be sensed elsewhere, and the effect transduced to the transporter. The possible pathways involved in the regulation of transport, including haemoglobin as a sensor, and phosphorylation/dephosphorylation reactions both in the transporter and its upstream effectors, are discussed.
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Affiliation(s)
- A Bogdanova
- Institute of Veterinary Physiology and the Zurich Center for Integrative Human Physiology, University of Zurich, Wintherturerstrasse 260, Zurich, Switzerland.
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