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Potential Novel Role of Membrane-Associated Carbonic Anhydrases in the Kidney. Int J Mol Sci 2023; 24:ijms24044251. [PMID: 36835660 PMCID: PMC9961601 DOI: 10.3390/ijms24044251] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/06/2023] [Accepted: 02/06/2023] [Indexed: 02/23/2023] Open
Abstract
Carbonic anhydrases (CAs), because they catalyze the interconversion of carbon dioxide (CO2) and water into bicarbonate (HCO3-) and protons (H+), thereby influencing pH, are near the core of virtually all physiological processes in the body. In the kidneys, soluble and membrane-associated CAs and their synergy with acid-base transporters play important roles in urinary acid secretion, the largest component of which is the reabsorption of HCO3- in specific nephron segments. Among these transporters are the Na+-coupled HCO3- transporters (NCBTs) and the Cl--HCO3- exchangers (AEs)-members of the "solute-linked carrier" 4 (SLC4) family. All of these transporters have traditionally been regarded as "HCO3-" transporters. However, recently our group has demonstrated that two of the NCBTs carry CO32- rather than HCO3- and has hypothesized that all NCBTs follow suit. In this review, we examine current knowledge on the role of CAs and "HCO3-" transporters of the SLC4 family in renal acid-base physiology and discuss how our recent findings impact renal acid secretion, including HCO3- reabsorption. Traditionally, investigators have associated CAs with producing or consuming solutes (CO2, HCO3-, and H+) and thus ensuring their efficient transport across cell membranes. In the case of CO32- transport by NCBTs, however, we hypothesize that the role of membrane-associated CAs is not the appreciable production or consumption of substrates but the minimization of pH changes in nanodomains near the membrane.
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Quintanova C, Himmerkus N, Svendsen SL, von Schwerdtner O, Merkel C, Pinckert L, Mutig K, Breiderhoff T, Müller D, Günzel D, Bleich M. Unrecognized role of claudin-10b in basolateral membrane infoldings of the thick ascending limb. Ann N Y Acad Sci 2022; 1517:266-278. [PMID: 35996827 DOI: 10.1111/nyas.14882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Claudin-10b is an important component of the tight junction in the thick ascending limb (TAL) of Henle's loop and allows paracellular sodium transport. In immunofluorescence stainings, claudin-10b-positive cells exhibited extensive extra staining of basolateral, column-like structures. The precise localization and function have so far remained elusive. In isolated cortical TAL segments from C57BL/6J mice, kidney-specific claudin-10 knockout mice (cKO), and respective litter mates (WT), we investigated the localization and protein expression and function by fluorescence microscopy and electrophysiological measurements. Ultrastructural analysis of TAL in kidney sections was performed by electron microscopy. Claudin-10b colocalized with the basolateral Na+ -K+ ATPase and the Cl- channel subunit barttin, but the lack of claudin-10b did not influence the localization or abundance of these proteins. However, the accessibility of the basolateral infolded extracellular space to ouabain or fluorescein was increased by basolateral Ca2+ removal and in the absence of claudin-10b. Ultrastructural analysis by electron microscopy revealed a widening of basolateral membrane infoldings in cKO in comparison to WT. We hypothesize that claudin-10b shapes neighboring membrane invaginations by trans interaction to stabilize and facilitate high-flux salt transport in a water-tight epithelium.
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Affiliation(s)
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Samuel L Svendsen
- Department of Biomedicine, Physiology, Aarhus University, Aarhus, Denmark
| | | | - Cosima Merkel
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Lennart Pinckert
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Kerim Mutig
- Department of Anatomy, Charité-Universitätsmedizin, Berlin, Germany
| | - Tilman Breiderhoff
- Department of Pediatrics, Division of Gastroenterology, Nephrology, and Metabolic Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Dominik Müller
- Department of Pediatrics, Division of Gastroenterology, Nephrology, and Metabolic Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Dorothee Günzel
- Clinical Physiology/Nutritional Medicine, Charité-Universitätsmedizin, Berlin, Germany
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
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3
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Novel QTL Associated with Aerenchyma-Mediated Radial Oxygen Loss (ROL) in Rice (Oryza sativa L.) under Iron (II) Sulfide. PLANTS 2022; 11:plants11060788. [PMID: 35336670 PMCID: PMC8948734 DOI: 10.3390/plants11060788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/03/2022] [Accepted: 03/15/2022] [Indexed: 01/04/2023]
Abstract
In rice, high radial oxygen loss (ROL) has been associated with the reduction in the activity of methanogens, therefore reducing the formation of methane (CH4) due to the abundance in application of nitrogen (N)-rich fertilizers. In this study, we evaluated the root growth behavior and ROL rate of a doubled haploid (DH) population (n = 117) and parental lines 93-11 (P1, indica) and Milyang352 (P2, japonica) in response to iron (II) sulfide (FeS). In addition, we performed a linkage mapping and quantitative trait locus (QTL) analysis on the same population for the target traits. The results of the phenotypic evaluation revealed that parental lines had distinctive root growth and ROL patterns, with 93-11 (indica) and Milyang352 (japonica) showing low and high ROL rates, respectively. This was also reflected in their derived population, indicating that 93.2% of the DH lines exhibited a high ROL rate and about 6.8% had a low ROL pattern. Furthermore, the QTL and linkage map analysis detected two QTLs associated with the control of ROL and root area on chromosomes 2 (qROL-2-1, 127 cM, logarithm of the odds (LOD) 3.04, phenotypic variation explained (PVE) 11.61%) and 8 (qRA-8-1, 97 cM, LOD 4.394, PVE 15.95%), respectively. The positive additive effect (2.532) of qROL-2-1 indicates that the allele from 93-11 contributed to the observed phenotypic variation for ROL. The breakthrough is that the qROL-2-1 harbors genes proposed to be involved in stress signaling, defense response mechanisms, and transcriptional regulation, among others. The qPCR results revealed that the majority of genes harbored by the qROL-2-1 recorded a higher transcript accumulation level in Milyang352 over time compared to 93-11. Another set of genes exhibited a high transcript abundance in P1 compared to P2, while a few were differentially regulated between both parents. Therefore, OsTCP7 and OsMYB21, OsARF8 genes encoding transcription factors (TFs), coupled with OsTRX, OsWBC8, and OsLRR2 are suggested to play important roles in the positive regulation of ROL in rice. However, the recorded differential expression of OsDEF7 and OsEXPA, and the decrease in OsNIP2, Oscb5, and OsPLIM2a TF expression between parental lines proposes them as being involved in the control of oxygen flux level in rice roots.
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Wang JL, Wang XY, Wang DK, Parker MD, Musa-Aziz R, Popple J, Guo YM, Min TX, Xia T, Tan M, Liu Y, Boron WF, Chen LM. Multiple acid-base and electrolyte disturbances upregulate NBCn1, NBCn2, IRBIT and L-IRBIT in the mTAL. J Physiol 2020; 598:3395-3415. [PMID: 32359081 DOI: 10.1113/jp279009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 04/22/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS The roles of the Na+ /HCO3 - cotransporters NBCn1 and NBCn2 as well as their activators IRBIT and L-IRBIT in the regulation of the mTAL transport of NH4 + , HCO3 - , and NaCl are investigated. Dietary challenges of NH4 Cl, NaHCO3 or NaCl all increase the abundance of NBCn1 and NBCn2 in the outer medulla. The three challenges generally produce parallel increases in the abundance of IRBIT and L-IRBIT in the outer medulla. Both IRBIT and L-IRBIT powerfully stimulate the activities of the mTAL isoforms of NBCn1 and NBCn2 as expressed in Xenopus oocytes. Our findings support the hypothesis that NBCn1, NBCn2, IRBIT and L-IRBIT appropriately promote NH4 + shunting but oppose HCO3 - and NaCl reabsorption in the mTAL, and thus are at the nexus of the regulation pathways for multiple renal transport processes. ABSTRACT The medullary thick ascending limb (mTAL) plays a key role in urinary acid and NaCl excretion. NBCn1 and NBCn2 are present in the basolateral mTAL, where NBCn1 promotes NH4 + shunting. IRBIT and L-IRBIT (the IRBITs) are two powerful activators of certain acid-base transporters. Here we use western blotting and immunofluorescence to examine the effects of multiple acid-base and electrolyte disturbances on expression of NBCn1, NBCn2 and the IRBITs in rat kidney. We also use electrophysiology to examine the functional effects of IRBITs on NBCn1 and NBCn2 in Xenopus oocytes. NH4 Cl-induced metabolic acidosis (MAc) substantially increases protein expression of NBCn1 and NBCn2 in the outer medulla (OM) of rat kidney. Surprisingly, NaHCO3 -induced metabolic alkalosis (MAlk) and high-salt diet (HSD) also increase expression of NBCn1 and NBCn2 (effect of NaHCO3 > HSD). Moreover, all three challenges generally increase OM expression of the IRBITs. In Xenopus oocytes, the IRBITs substantially increase the activities of NBCn1 and NBCn2. We propose that upregulation of basolateral NBCn1 and NBCn2 plus the IRBITs in the mTAL: (1) promotes NH4 + shunting by increasing basolateral HCO3 - uptake to neutralize apical NH4 + uptake during MAc; (2) inhibits HCO3 - reabsorption during MAlk by opposing HCO3 - efflux via the basolateral anion exchanger AE2; and (3) inhibits NaCl reabsorption by mediating (with AE2) net NaCl backflux into the mTAL cell during HSD. Thus, NBCn1, NBCn2 and the IRBITs are at the nexus of the regulatory pathways for multiple renal transport processes.
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Affiliation(s)
- Jin-Lin Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Xiao-Yu Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Deng-Ke Wang
- Department of Physiology and Biophysics, Department of Medicine, Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, Department of Medicine, Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, University at Buffalo: The State University of New York, Buffalo, NY, 14214, USA
| | - Raif Musa-Aziz
- Department of Physiology and Biophysics, Department of Medicine, Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, 05508-900, Brazil
| | - Jacob Popple
- Department of Physiology and Biophysics, Department of Medicine, Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Yi-Min Guo
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Tian-Xin Min
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Tian Xia
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Min Tan
- School of Optical & Electronic Information, Huazhong University of Science & Technology, Wuhan, 430074, China.,Wuhan National Laboratory of Optoelectronics, Wuhan, 430074, China
| | - Ying Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
| | - Walter F Boron
- Department of Physiology and Biophysics, Department of Medicine, Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Li-Ming Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science & Technology, Huazhong University of Science & Technology, Wuhan, Hubei, 430074, China
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Li Q, Aalling NN, Förstera B, Ertürk A, Nedergaard M, Møllgård K, Xavier ALR. Aquaporin 1 and the Na +/K +/2Cl - cotransporter 1 are present in the leptomeningeal vasculature of the adult rodent central nervous system. Fluids Barriers CNS 2020; 17:15. [PMID: 32046744 PMCID: PMC7014736 DOI: 10.1186/s12987-020-0176-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/30/2020] [Indexed: 12/26/2022] Open
Abstract
Background The classical view of cerebrospinal fluid (CSF) production posits the choroid plexus as its major source. Although previous studies indicate that part of CSF production occurs in the subarachnoid space (SAS), the mechanisms underlying extra-choroidal CSF production remain elusive. We here investigated the distributions of aquaporin 1 (AQP1) and Na+/K+/2Cl− cotransporter 1 (NKCC1), key proteins for choroidal CSF production, in the adult rodent brain and spinal cord. Methods We have accessed AQP1 distribution in the intact brain using uDISCO tissue clearing technique and by Western blot. AQP1 and NKCC1 cellular localization were accessed by immunohistochemistry in brain and spinal cord obtained from adult rodents. Imaging was performed using light-sheet, confocal and bright field light microscopy. Results We determined that AQP1 is widely distributed in the leptomeningeal vasculature of the intact brain and that its glycosylated isoform is the most prominent in different brain regions. Moreover, AQP1 and NKCC1 show specific distributions in the smooth muscle cell layer of penetrating arterioles and veins in the brain and spinal cord, and in the endothelia of capillaries and venules, restricted to the SAS vasculature. Conclusions Our results shed light on the molecular framework that may underlie extra-choroidal CSF production and we propose that AQP1 and NKCC1 within the leptomeningeal vasculature, specifically at the capillary level, are poised to play a role in CSF production throughout the central nervous system.
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Affiliation(s)
- Qianliang Li
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Nadia N Aalling
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Benjamin Förstera
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377, Munich, Germany
| | - Ali Ertürk
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig Maximilians University of Munich (LMU), 81377, Munich, Germany
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark.,Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Anna L R Xavier
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Copenhagen, 2200, Copenhagen, Denmark.
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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Abstract
In chemistry, the ratio of all dissolved solutes to the solution's volume yields the osmotic concentration. The present Review uses this chemical perspective to examine how insects deal with challenges to extracellular fluid (ECF) volume, solute content and osmotic concentration (pressure). Solute/volume plots of the ECF (hemolymph) reveal that insects tolerate large changes in all three of these ECF variables. Challenges beyond those tolerances may be 'corrected' or 'compensated'. While a correction simply reverses the challenge, compensation accommodates the challenge with changes in the other two variables. Most insects osmoregulate by keeping ECF volume and osmotic concentration within a wide range of tolerance. Other insects osmoconform, allowing the ECF osmotic concentration to match the ambient osmotic concentration. Aphids are unique in handling solute and volume loads largely outside the ECF, in the lumen of the gut. This strategy may be related to the apparent absence of Malpighian tubules in aphids. Other insects can suspend ECF homeostasis altogether in order to survive extreme temperatures. Thus, ECF homeostasis in insects is highly dynamic and plastic, which may partly explain why insects remain the most successful class of animals in terms of both species number and biomass.
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Affiliation(s)
- Klaus W Beyenbach
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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Wintmo P, Johansen SH, Hansen PBL, Lindholt JS, Urbonavicius S, Rasmussen LM, Bie P, Jensen BL, Stubbe J. The water channel AQP1 is expressed in human atherosclerotic vascular lesions and AQP1 deficiency augments angiotensin II-induced atherosclerosis in mice. Acta Physiol (Oxf) 2017; 220:446-460. [PMID: 28129470 DOI: 10.1111/apha.12853] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/29/2016] [Accepted: 01/22/2017] [Indexed: 12/22/2022]
Abstract
AIM The water channel aquaporin 1 (AQP1) promotes endothelial cell migration. It was hypothesized that AQP1 promotes neovascularization and growth of atherosclerotic plaques. METHODS AQP1 immunoreactivity and protein abundance was examined in human and murine atherosclerotic lesions and aortic aneurysms. Apolipoprotein E (ApoE) knockout (-/-) and AQP1-/-ApoE-/- mice were developed and fed Western diet (WD) for 8 and 16 weeks to accelerate the atherosclerosis process. In ApoE-/- and AQP1-/-ApoE-/- mice abdominal aortic aneurysms (AAA) were induced by angiotensin II (ANGII) infusion by osmotic minipumps for 4 weeks. RESULTS In human atherosclerotic lesions and AAA, AQP1 immunoreactive protein was associated with intralesional small vessels. In ApoE-/- mouse aorta, APQ1 mRNA levels were increased with time on WD (n = 7-9, P < 0.003). Both in murine lesions at the aortic root and in the abdominal aortic aneurysmal wall, AQP1 immunoreactivity was associated with microvascular structures. The atherosclerotic lesion burden was enhanced significantly in ANGII-infused AQP1-/-ApoE-/- mice compared with ApoE-/- mice, but neither incidence nor progression of AAA was different. The aortic lesion burden increased with time on WD but was not different between ApoE-/- and AQP1-/-ApoE-/- mice at either 8 or 16 weeks (n = 13-15). Baseline blood pressure and ANGII-induced hypertension were not different between genotypes. CONCLUSION AQP1 is expressed in atherosclerotic lesion neovasculature in human and mouse arteries and AQP1 deficiency augments lesion development in ANGII-promoted atherosclerosis in mice. Normal function of AQP1 affords cardiovascular protection.
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Affiliation(s)
- P. Wintmo
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - S. H. Johansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - P. B. L. Hansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - J. S. Lindholt
- Department of Cardiothoracic and Vascular Surgery T; University Hospital of Odense; Odense C Denmark
| | - S. Urbonavicius
- Cardiovascular Research Centre; Viborg Hospital; Viborg Denmark
| | - L. M. Rasmussen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
- Department of Clinical Biochemistry and Pharmacology; Odense University Hospital; Odense C Denmark
| | - P. Bie
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - B. L. Jensen
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
| | - J. Stubbe
- Department of Cardiovascular and Renal Research; Institute of Molecular Biology; University of Southern Denmark; Odense C Denmark
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Hsu K, Lee TY, Periasamy A, Kao FJ, Li LT, Lin CY, Lin HJ, Lin M. Adaptable interaction between aquaporin-1 and band 3 reveals a potential role of water channel in blood CO 2 transport. FASEB J 2017; 31:4256-4264. [PMID: 28596233 DOI: 10.1096/fj.201601282r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/22/2017] [Indexed: 12/22/2022]
Abstract
Human CO2 respiration requires rapid conversion between CO2 and HCO3- Carbonic anhydrase II facilitates this reversible reaction inside red blood cells, and band 3 [anion exchanger 1 (AE1)] provides a passage for HCO3- flux across the cell membrane. These 2 proteins are core components of the CO2 transport metabolon. Intracellular H2O is necessary for CO2/HCO3- conversion. However, abundantly expressed aquaporin 1 (AQP1) in erythrocytes is thought not to be part of band 3 complexes or the CO2 transport metabolon. To solve this conundrum, we used Förster resonance energy transfer (FRET) measured by fluorescence lifetime imaging (FLIM-FRET) and identified interaction between aquaporin-1 and band 3 at a distance of 8 nm, within the range of dipole-dipole interaction. Notably, their interaction was adaptable to membrane tonicity changes. This suggests that the function of AQP1 in tonicity response could be coupled or correlated to its function in band 3-mediated CO2/HCO3- exchange. By demonstrating AQP1 as a mobile component of the CO2 transport metabolon, our results uncover a potential role of water channel in blood CO2 transport and respiration.-Hsu, K., Lee, T.-Y., Periasamy, A., Kao, F.-J., Li, L.-T., Lin, C.-Y., Lin, H.-J., Lin, M. Adaptable interaction between aquaporin-1 and band 3 reveals a potential role of water channel in blood CO2 transport.
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Affiliation(s)
- Kate Hsu
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan;
| | - Ting-Ying Lee
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia, USA
| | - Fu-Jen Kao
- Institute of Biophotonics, National Yang-Ming University, Taipei, Taiwan
| | - Li-Tzu Li
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Chuang-Yu Lin
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto, Japan
| | - Hui-Ju Lin
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
| | - Marie Lin
- Transfusion Medicine Laboratory, Mackay Memorial Hospital, Tamsui, Taiwan
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10
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Nguyen T, Toussaint J, Xue Y, Raval C, Cancel L, Russell S, Shou Y, Sedes O, Sun Y, Yakobov R, Tarbell JM, Jan KM, Rumschitzki DS. Aquaporin-1 facilitates pressure-driven water flow across the aortic endothelium. Am J Physiol Heart Circ Physiol 2015; 308:H1051-64. [PMID: 25659484 PMCID: PMC4551120 DOI: 10.1152/ajpheart.00499.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 01/23/2015] [Indexed: 01/23/2023]
Abstract
Aquaporin-1, a ubiquitous water channel membrane protein, is a major contributor to cell membrane osmotic water permeability. Arteries are the physiological system where hydrostatic dominates osmotic pressure differences. In the present study, we show that the walls of large conduit arteries constitute the first example where hydrostatic pressure drives aquaporin-1-mediated transcellular/transendothelial flow. We studied cultured aortic endothelial cell monolayers and excised whole aortas of male Sprague-Dawley rats with intact and inhibited aquaporin-1 activity and with normal and knocked down aquaporin-1 expression. We subjected these systems to transmural hydrostatic pressure differences at zero osmotic pressure differences. Impaired aquaporin-1 endothelia consistently showed reduced engineering flow metrics (transendothelial water flux and hydraulic conductivity). In vitro experiments with tracers that only cross the endothelium paracellularly showed that changes in junctional transport cannot explain these reductions. Percent reductions in whole aortic wall hydraulic conductivity with either chemical blocking or knockdown of aquaporin-1 differed at low and high transmural pressures. This observation highlights how aquaporin-1 expression likely directly influences aortic wall mechanics by changing the critical transmural pressure at which its sparse subendothelial intima compresses. Such compression increases transwall flow resistance. Our endothelial and historic erythrocyte membrane aquaporin density estimates were consistent. In conclusion, aquaporin-1 significantly contributes to hydrostatic pressure-driven water transport across aortic endothelial monolayers, both in culture and in whole rat aortas. This transport, and parallel junctional flow, can dilute solutes that entered the wall paracellularly or through endothelial monolayer disruptions. Lower atherogenic precursor solute concentrations may slow their intimal entrainment kinetics.
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Affiliation(s)
- Tieuvi Nguyen
- Department of Biomedical Engineering, City College of the City University of New York, New York, New York
| | - Jimmy Toussaint
- Department of Chemical Engineering, City College of the City University of New York, New York, New York
| | - Yan Xue
- Department of Chemical Engineering, City College of the City University of New York, New York, New York; Biology Department, City College and GSUC of The City College of New York, New York, New York; and
| | - Chirag Raval
- Department of Biomedical Engineering, City College of the City University of New York, New York, New York
| | - Limary Cancel
- Department of Biomedical Engineering, City College of the City University of New York, New York, New York
| | - Stewart Russell
- Department of Biomedical Engineering, City College of the City University of New York, New York, New York
| | - Yixin Shou
- Department of Chemical Engineering, City College of the City University of New York, New York, New York
| | - Omer Sedes
- Department of Chemical Engineering, City College of the City University of New York, New York, New York
| | - Yu Sun
- Department of Chemical Engineering, City College of the City University of New York, New York, New York
| | - Roman Yakobov
- Department of Chemical Engineering, City College of the City University of New York, New York, New York
| | - John M Tarbell
- Department of Biomedical Engineering, City College of the City University of New York, New York, New York
| | - Kung-ming Jan
- Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
| | - David S Rumschitzki
- Department of Chemical Engineering, City College of the City University of New York, New York, New York; Biology Department, City College and GSUC of The City College of New York, New York, New York; and Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, New York
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Abstract
The thick ascending limb occupies a central anatomic and functional position in human renal physiology, with critical roles in the defense of the extracellular fluid volume, the urinary concentrating mechanism, calcium and magnesium homeostasis, bicarbonate and ammonium homeostasis, and urinary protein composition. The last decade has witnessed tremendous progress in the understanding of the molecular physiology and pathophysiology of this nephron segment. These advances are the subject of this review, with emphasis on particularly recent developments.
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Affiliation(s)
- David B Mount
- Renal Division, Brigham and Women's Hospital, Veterans Affairs Boston Healthcare System, Boston, Massachusetts
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Pannabecker TL. Comparative physiology and architecture associated with the mammalian urine concentrating mechanism: role of inner medullary water and urea transport pathways in the rodent medulla. Am J Physiol Regul Integr Comp Physiol 2013; 304:R488-503. [PMID: 23364530 PMCID: PMC3627947 DOI: 10.1152/ajpregu.00456.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 01/25/2013] [Indexed: 01/07/2023]
Abstract
Comparative studies of renal structure and function have potential to provide insights into the urine-concentrating mechanism of the mammalian kidney. This review focuses on the tubular transport pathways for water and urea that play key roles in fluid and solute movements between various compartments of the rodent renal inner medulla. Information on aquaporin water channel and urea transporter expression has increased our understanding of functional segmentation of medullary thin limbs of Henle's loops, collecting ducts, and vasa recta. A more complete understanding of membrane transporters and medullary architecture has identified new and potentially significant interactions between these structures and the interstitium. These interactions are now being introduced into our concept of how the inner medullary urine-concentrating mechanism works. A variety of regulatory pathways lead directly or indirectly to variable patterns of fluid and solute movements among the interstitial and tissue compartments. Animals with the ability to produce highly concentrated urine, such as desert species, are considered to exemplify tubular structure and function that optimize urine concentration. These species may provide unique insights into the urine-concentrating process.(1)
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Affiliation(s)
- Thomas L Pannabecker
- Department of Physiology, AHSC 4128, University of Arizona Health Sciences Center, 1501 N. Campbell Ave., Tucson, AZ 85724-5051, USA.
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13
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Sands JM. The thick ascending limb and water channels: half-full or half-empty. Am J Physiol Renal Physiol 2012; 303:F619-20. [PMID: 22696605 DOI: 10.1152/ajprenal.00318.2012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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