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Tsikas D. Acetazolamide and human carbonic anhydrases: retrospect, review and discussion of an intimate relationship. J Enzyme Inhib Med Chem 2024; 39:2291336. [PMID: 38078375 DOI: 10.1080/14756366.2023.2291336] [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: 10/24/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Acetazolamide (AZM) is a strong pharmacological sulphonamide-type (R-SO2-NH2, pKa 7.2) inhibitor of the activity of several carbonic anhydrase (CA) isoforms, notably of renal CA II (Ki, 12 nM) and CA IV (Ki, 74 nM). AZM is clinically used for about eighty years in various diseases including epilepsy and glaucoma. Pharmacological AZM increases temporarily the urinary excretion of bicarbonate (HCO3-) and sodium ions (Na+) and sustainably the urinary pH. AZM is excreted almost unchanged over several hours at high rates in the urine. Closely parallel concentrations of circulating and excretory AZM are observed upon administration of therapeutical doses of AZM. In a proof-of-principle study, we investigated the effects of the ingestion of a 250-mg AZM-containing tablet by a healthy volunteer on the urinary excretion of organic and inorganic substances over 5 h (range, 0, 0.5, 1, 1.5, 2, 3, 4, 5 h). Measured analytes included: AZM, amino acids and their metabolites such as guanidinoacetate, i.e. the precursor of creatine, of asymmetrically (ADMA) and symmetrically (SDMA) dimethylated arginine, nitrite (O = N-O-, pKa 3.4) and nitrate (O2N-O-, pKa -1.37), the major metabolites of nitric oxide (NO), the C-H acidic malondialdehyde (MDA; (CHO)2CH2, pKa 4.5), and creatinine for correction of analytes excretion. All analytes were measured by validated isotopologues using gas chromatography-mass spectrometry (GC-MS) methods. AZM excretion in the urine reached its maximum value after 2 h and was fairly stable for the next 3 h. Time series analysis by the ARIMA method was performed. AZM ingestion increased temporarily the urinary excretion of the amino acids Leu + Ile, nitrite and nitrate, decreased temporarily the urinary excretion of other amino acids. AZM decreased sustainably the urinary excretion of MDA, a biomarker of oxidative stress (i.e. lipid peroxidation). Whether this decrease is due to inhibition of the excretion of MDA or attenuation of oxidative stress by AZM is unknown. The acute and chronic effects of AZM on the urinary excretion of electrolytes and physiological substances reported in the literature are discussed in depth in the light of its extraordinary pharmacokinetics and pharmacodynamics. Tolerance development/drug resistance to AZM in chronic use and potential mechanisms are also addressed.
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Affiliation(s)
- Dimitrios Tsikas
- Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, Hannover, Germany
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2
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Joseph FM, Kaldenhoff R. Tobacco aquaporin NtAQP1 and human aquaporin hAQP1 contribute to single cell photosynthesis in Synechococcus. Biol Cell 2024; 116:e2470003. [PMID: 38653736 DOI: 10.1111/boc.202470003] [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: 01/10/2024] [Revised: 03/02/2024] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND INFORMATION Aquaporins are H2O-permeable membrane protein pores. However, some aquaporins are also permeable to other substances such as CO2. In higher plants, overexpression of such aquaporins has already led to an enhanced photosynthetic performance due to improved CO2 mesophyll conductance. In this work, we investigated the effects of such aquaporins on unicellular photosynthetically active organisms, specifically cyanobacteria. RESULTS Overexpression of aquaporins NtAQP1 or hAQP1 that might have a function to improve CO2 membrane permeability lead to increased photosynthesis rates in the cyanobacterium Synechococcus sp. PCC7002 as concluded by the rate of evolved O2. A shift in the Plastoquinone pool state of the cells supports our findings. Water permeable aquaporins without CO2 permeability, such as NtPIP2;1, do not have this effect. CONCLUSIONS AND SIGNIFICANCE We conclude that also in single cell organisms like cyanobacteria, membrane CO2 conductivity could be rate limiting and CO2-porins reduce the respective membrane resistance. We could show that besides the tobacco aquaporin NtAQP1 also the human hAQP1 most likely functions as CO2 diffusion facilitator in the photosynthesis assay.
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Affiliation(s)
- Franziska M Joseph
- Department of Biology, Applied Plant Sciences, Technical University of Darmstadt, Darmstadt, Germany
| | - Ralf Kaldenhoff
- Department of Biology, Applied Plant Sciences, Technical University of Darmstadt, Darmstadt, Germany
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3
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Galos G, Rabai M, Szabo R, Szalai R, Toth K, Hegyi P, Sandor B. The influence of triglyceride and low-density-lipoprotein target levels on microcirculation: Is there a difference? Heliyon 2024; 10:e27954. [PMID: 38515677 PMCID: PMC10955303 DOI: 10.1016/j.heliyon.2024.e27954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/08/2024] [Accepted: 03/08/2024] [Indexed: 03/23/2024] Open
Abstract
Background and aims This study aimed to validate the role of high low-density lipoprotein cholesterol [LDL-C] and triglyceride [TG] treatment target levels on the microcirculation in a very high and high cardiovascular risk group. Methods 119 patients with high or very high cardiovascular [CV] risk were included. We have registered the main co-morbidities, smoking habits, body mass index [BMI] and the lipid lowering medication. Hematocrit, whole blood viscosity [WBV] and plasma viscosity [PV], red blood cell [RBC] aggregation and deformability and fibrinogen, total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], LDL-C and TG levels were determined. Results The investigation found significantly higher PV values in patients with non-target LDL-C, associated with higher fibrinogen level. Non-target TG was related to deteriorated microcirculatory parameters, as significantly higher RBC aggregation, lower RBC deformability, and higher WBV and PV. The main microcirculatory benefit in diabetes could be gained from target level of TG, in chronic coronary syndrome [CCS] patients it is more advantageous to reach both LDL-C and TG target. Conclusion The results could highlight, that TG should play a role in failing microcirculation and cause potentially life-threatening complications, which would worsen the survival and quality of life of high or very high risk CV patients.
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Affiliation(s)
- Gergely Galos
- Department of Medicine, Division of Preventive Cardiology and Rehabilitation, University of Pecs, School of Medicine, Pecs, Hungary
- Department of Medicine, Szentagothai Research Centre, University of Pecs, Medical School, Pecs, Hungary
| | - Miklos Rabai
- Department of Medicine, Division of Cardiology, University of Pecs, School of Medicine, Pecs, Hungary
| | - Reka Szabo
- Department of Medicine, Division of Preventive Cardiology and Rehabilitation, University of Pecs, School of Medicine, Pecs, Hungary
| | - Rita Szalai
- Department of Medicine, Division of Preventive Cardiology and Rehabilitation, University of Pecs, School of Medicine, Pecs, Hungary
| | - Kalman Toth
- Department of Medicine, Division of Cardiology, University of Pecs, School of Medicine, Pecs, Hungary
| | - Peter Hegyi
- Institute for Translational Medicine, University of Pecs, School of Medicine, Pecs, Hungary
| | - Barbara Sandor
- Department of Medicine, Division of Preventive Cardiology and Rehabilitation, University of Pecs, School of Medicine, Pecs, Hungary
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4
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Bolshette N, Ezagouri S, Dandavate V, Karavaeva I, Golik M, Wang H, Espenshade PJ, Osborne TF, Han X, Asher G. Carbon dioxide regulates cholesterol levels through SREBP2. PLoS Biol 2023; 21:e3002367. [PMID: 37967106 PMCID: PMC10651039 DOI: 10.1371/journal.pbio.3002367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/06/2023] [Indexed: 11/17/2023] Open
Abstract
In mammals, O2 and CO2 levels are tightly regulated and are altered under various pathological conditions. While the molecular mechanisms that participate in O2 sensing are well characterized, little is known regarding the signaling pathways that participate in CO2 signaling and adaptation. Here, we show that CO2 levels control a distinct cellular transcriptional response that differs from mere pH changes. Unexpectedly, we discovered that CO2 regulates the expression of cholesterogenic genes in a SREBP2-dependent manner and modulates cellular cholesterol accumulation. Molecular dissection of the underlying mechanism suggests that CO2 triggers SREBP2 activation through changes in endoplasmic reticulum (ER) membrane cholesterol levels. Collectively, we propose that SREBP2 participates in CO2 signaling and that cellular cholesterol levels can be modulated by CO2 through SREBP2.
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Affiliation(s)
- Nityanand Bolshette
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Saar Ezagouri
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Vaishnavi Dandavate
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Iuliia Karavaeva
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Marina Golik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Hu Wang
- The Sam & Ann Barshop Institute for Longevity & Aging Studies, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Peter J. Espenshade
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Timothy F. Osborne
- Institute for Fundamental Biomedical Research, Johns Hopkins All Children’s Hospital, and Medicine in the Division of Endocrinology, Diabetes and Metabolism of the Johns Hopkins University School of Medicine, Petersburg, Florida, United States of America
| | - Xianlin Han
- The Sam & Ann Barshop Institute for Longevity & Aging Studies, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Gad Asher
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Chen J, Yue K, Shen L, Zheng C, Zhu Y, Han K, Kai L. Aquaporins and CO 2 diffusion across biological membrane. Front Physiol 2023; 14:1205290. [PMID: 37383148 PMCID: PMC10293838 DOI: 10.3389/fphys.2023.1205290] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/05/2023] [Indexed: 06/30/2023] Open
Abstract
Despite the physiological significance of effective CO2 diffusion across biological membranes, the underlying mechanism behind this process is not yet resolved. Particularly debatable is the existence of CO2-permeable aquaporins. The lipophilic characteristic of CO2 should, according to Overton's rule, result in a rapid flux across lipid bilayers. However, experimental evidence of limited membrane permeability poses a challenge to this idea of free diffusion. In this review, we summarized recent progress with regard to CO2 diffusion, and discussed the physiological effects of altered aquaporin expression, the molecular mechanisms of CO2 transport via aquaporins, and the function of sterols and other membrane proteins in CO2 permeability. In addition, we highlight the existing limits in measuring CO2 permeability and end up with perspectives on resolving such argument either by determining the atomic resolution structure of CO2 permeable aquaporins or by developing new methods for measuring permeability.
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Affiliation(s)
- Junyu Chen
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Ke Yue
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Lulu Shen
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Chuncui Zheng
- Hangzhou Institute of Test and Calibration for Quality and Technology Supervision, Hangzhou, China
| | - Yiyong Zhu
- Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Kun Han
- Jiangsu Keybio Co., Ltd, Xuzhou, China
| | - Lei Kai
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
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Greiser M, Karbowski M, Kaplan AD, Coleman AK, Verhoeven N, Mannella CA, Lederer WJ, Boyman L. Calcium and bicarbonate signaling pathways have pivotal, resonating roles in matching ATP production to demand. eLife 2023; 12:e84204. [PMID: 37272417 PMCID: PMC10284600 DOI: 10.7554/elife.84204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 06/01/2023] [Indexed: 06/06/2023] Open
Abstract
Mitochondrial ATP production in ventricular cardiomyocytes must be continually adjusted to rapidly replenish the ATP consumed by the working heart. Two systems are known to be critical in this regulation: mitochondrial matrix Ca2+ ([Ca2+]m) and blood flow that is tuned by local cardiomyocyte metabolic signaling. However, these two regulatory systems do not fully account for the physiological range of ATP consumption observed. We report here on the identity, location, and signaling cascade of a third regulatory system -- CO2/bicarbonate. CO2 is generated in the mitochondrial matrix as a metabolic waste product of the oxidation of nutrients. It is a lipid soluble gas that rapidly permeates the inner mitochondrial membrane and produces bicarbonate in a reaction accelerated by carbonic anhydrase. The bicarbonate level is tracked physiologically by a bicarbonate-activated soluble adenylyl cyclase (sAC). Using structural Airyscan super-resolution imaging and functional measurements we find that sAC is primarily inside the mitochondria of ventricular cardiomyocytes where it generates cAMP when activated by bicarbonate. Our data strongly suggest that ATP production in these mitochondria is regulated by this cAMP signaling cascade operating within the inter-membrane space by activating local EPAC1 (Exchange Protein directly Activated by cAMP) which turns on Rap1 (Ras-related protein-1). Thus, mitochondrial ATP production is increased by bicarbonate-triggered sAC-signaling through Rap1. Additional evidence is presented indicating that the cAMP signaling itself does not occur directly in the matrix. We also show that this third signaling process involving bicarbonate and sAC activates the mitochondrial ATP production machinery by working independently of, yet in conjunction with, [Ca2+]m-dependent ATP production to meet the energy needs of cellular activity in both health and disease. We propose that the bicarbonate and calcium signaling arms function in a resonant or complementary manner to match mitochondrial ATP production to the full range of energy consumption in ventricular cardiomyocytes.
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Affiliation(s)
- Maura Greiser
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Physiology, University of Marylan School of MedicineBaltimoreUnited States
- Claude D. Pepper Older Americans Independence Center, University of Maryland School of MedicineBaltimoreUnited States
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimoreUnited States
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland Baltimore School of MedicineBaltimoreUnited States
| | - Aaron David Kaplan
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland School of MedicineBaltimoreUnited States
| | - Andrew Kyle Coleman
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Physiology, University of Marylan School of MedicineBaltimoreUnited States
| | - Nicolas Verhoeven
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Biochemistry and Molecular Biology, University of Maryland School of MedicineBaltimoreUnited States
| | - Carmen A Mannella
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Physiology, University of Marylan School of MedicineBaltimoreUnited States
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Physiology, University of Marylan School of MedicineBaltimoreUnited States
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland Baltimore School of MedicineBaltimoreUnited States
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of MedicineBaltimoreUnited States
- Department of Physiology, University of Marylan School of MedicineBaltimoreUnited States
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland Baltimore School of MedicineBaltimoreUnited States
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Shu Y, Huang G, Zhang Q, Peng S, Li Y. Reduction of photosynthesis under P deficiency is mainly caused by the decreased CO 2 diffusional capacities in wheat (Triticum aestivum L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 198:107680. [PMID: 37031546 DOI: 10.1016/j.plaphy.2023.107680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/13/2023] [Accepted: 04/03/2023] [Indexed: 05/07/2023]
Abstract
Phosphorus is one of the most important essential mineral elements for plant growth and development. It has been widely recognized that phosphorus deficiency can lead to the significant declines in leaf photosynthetic rate and leaf area. However, the internal mechanism associated with the leaf anatomical traits has not been well understood. In present study, a hydroponic experiment was conducted to study the effect of phosphorus deficiency on leaf growth and photosynthesis in Jimai 22 (JM22, Triticum aestivum L.) and Suk Landarace 26 (SL26, Triticum aestivum L.). With the decrease in phosphorus concentration, leaf photosynthetic rate and leaf area in SL26 and JM22 all decreased significantly, but the decrease in leaf area occurred earlier than that in leaf photosynthetic rate. The thresholds of phosphorus concentration to maintain a high photosynthesis were 145.5 and 138.7 mg m-2, respectively, in SL26 and JM22; and they were 197.5 and 212.0 mg m-2, respectively, for leaf growth. The decrease in leaf photosynthetic rate under low P conditions was mainly caused by the lowered stomatal conductance and mesophyll conductance, and to a less extent by the decrease in biochemical capacities. The decrease in stomatal conductance was attributed to the smaller vascular bundle area, xylem conduits area and the lower leaf hydraulic conductance. However, the reduction in mesophyll conductance was not related to either the cell wall thickness or the development of chloroplast.
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Affiliation(s)
- Yu Shu
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
| | - Guanjun Huang
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, School of Agricultural Sciences, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China.
| | - Qiangqiang Zhang
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
| | - Yong Li
- National Key Laboratory of Crop Genetic Improvement, Ministry of Agriculture Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
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8
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Aquaporins Display a Diversity in their Substrates. J Membr Biol 2023; 256:1-23. [PMID: 35986775 DOI: 10.1007/s00232-022-00257-7] [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: 12/29/2021] [Accepted: 07/13/2022] [Indexed: 02/07/2023]
Abstract
Aquaporins constitute a family of transmembrane proteins that function to transport water and other small solutes across the cell membrane. Aquaporins family members are found in diverse life forms. Aquaporins share the common structural fold consisting of six transmembrane alpha helices with a central water-transporting channel. Four such monomers assemble together to form tetramers as their biological unit. Initially, aquaporins were discovered as water-transporting channels, but several studies supported their involvement in mediating the facilitated diffusion of different solutes. The so-called water channel is able to transport a variety of substrates ranging from a neutral molecule to a charged molecule or a small molecule to a bulky molecule or even a gas molecule. This article gives an overview of a diverse range of substrates conducted by aquaporin family members. Prime focus is on human aquaporins where aquaporins show a wide tissue distribution and substrate specificity leading to various physiological functions. This review also highlights the structural mechanisms leading to the transport of water and glycerol. More research is needed to understand how one common fold enables the aquaporins to transport an array of solutes.
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9
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Geng X, Shao G, Jiang T, Yang B. Transport Characteristics of Aquaporins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:53-64. [PMID: 36717486 DOI: 10.1007/978-981-19-7415-1_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aquaporins (AQP) are a class of the integral membrane proteins. The main physiological function of AQPs is to facilitate the water transport across plasma membrane of cells. However, the transport of various kinds of small molecules by AQPs is an interesting topic. Studies using in vitro cell models have found that AQPs mediated transport of small molecules, including glycerol, urea, carbamides, polyols, purines, pyrimidines and monocarboxylates, and gases such as CO2, NO, NH3, H2O2 and O2, although the high intrinsic membrane permeabilities for these gases make aquaporin-facilitated transport not dominant in physiological mechanism. AQPs are also considered to transport silicon, antimonite, arsenite and some ions; however, most data about transport characteristics of AQPs are derived from in vitro experiments. The physiological significance of AQPs that are permeable to various small molecules is necessary to be determined by in vivo experiments. This chapter will provide information about the transport characteristics of AQPs.
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Affiliation(s)
- Xiaoqiang Geng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Guangying Shao
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Tao Jiang
- College of Basic Medicine, Beihua University, Jilin, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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10
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Al-Samir S, Yildirim AÖ, Sidhaye VK, King LS, Breves G, Conlon TM, Stoeger C, Gailus-Durner V, Fuchs H, Hrabé de Angelis M, Gros G, Endeward V. Aqp5 -/- mice exhibit reduced maximal body O 2 consumption under cold exposure, normal pulmonary gas exchange, and impaired formation of brown adipose tissue. Am J Physiol Regul Integr Comp Physiol 2023; 324:R109-R119. [PMID: 36409022 DOI: 10.1152/ajpregu.00130.2022] [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: 11/23/2022]
Abstract
The fundamental body functions that determine maximal O2 uptake (V̇o2max) have not been studied in Aqp5-/- mice (aquaporin 5, AQP5). We measured V̇o2max to globally assess these functions and then investigated why it was found altered in Aqp5-/- mice. V̇o2max was measured by the Helox technique, which elicits maximal metabolic rate by intense cold exposure of the animals. We found V̇o2max reduced in Aqp5-/- mice by 20%-30% compared with wild-type (WT) mice. As AQP5 has been implicated to act as a membrane channel for respiratory gases, we studied whether this is caused by the known lack of AQP5 in the alveolar epithelial membranes of Aqp5-/- mice. Lung function parameters as well as arterial O2 saturation were normal and identical between Aqp5-/- and WT mice, indicating that AQP5 does not contribute to pulmonary O2 exchange. The cause for the decreased V̇o2max thus might be found in decreased O2 consumption of an intensely O2-consuming peripheral organ such as activated brown adipose tissue (BAT). We found indeed that absence of AQP5 greatly reduces the amount of interscapular BAT formed in response to 4 wk of cold exposure, from 63% in WT to 25% in Aqp5-/- animals. We conclude that lack of AQP5 does not affect pulmonary O2 exchange, but greatly inhibits transformation of white to brown adipose tissue. As under cold exposure, BAT is a major source of the animals' heat production, reduction of BAT likely causes the decrease in V̇o2max under this condition.
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Affiliation(s)
- Samer Al-Samir
- Zentrum Physiologie, AG Vegetative Physiologie, Medizinische Hochschule, Hannover, Germany
| | - Ali Önder Yildirim
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), München, Germany
| | - Venkataramana K Sidhaye
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Landon S King
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Gerhard Breves
- Institut für Physiologie und Zellbiologie, Tierärztliche Hochschule Hannover, Hannover, Germany
| | - Thomas M Conlon
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), München, Germany
| | - Claudia Stoeger
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, GmbH, Neuherberg, Germany
| | - Valerie Gailus-Durner
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, GmbH, Neuherberg, Germany
| | - Helmut Fuchs
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, GmbH, Neuherberg, Germany
| | - Martin Hrabé de Angelis
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, GmbH, Neuherberg, Germany.,German Center for Diabetes Research, Neuherberg, Germany.,Chair of Experimental Genetics, Technische Universität München School of Life Sciences, Technische Universität München, Freising, Germany
| | - Gerolf Gros
- Zentrum Physiologie, AG Vegetative Physiologie, Medizinische Hochschule, Hannover, Germany
| | - Volker Endeward
- Zentrum Physiologie, AG Vegetative Physiologie, Medizinische Hochschule, Hannover, Germany
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11
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Niesor EJ, Nader E, Perez A, Lamour F, Benghozi R, Remaley A, Thein SL, Connes P. Red Blood Cell Membrane Cholesterol May Be a Key Regulator of Sickle Cell Disease Microvascular Complications. MEMBRANES 2022; 12:1134. [PMID: 36422126 PMCID: PMC9694375 DOI: 10.3390/membranes12111134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/06/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Cell membrane lipid composition, especially cholesterol, affects many functions of embedded enzymes, transporters and receptors in red blood cells (RBC). High membrane cholesterol content affects the RBCs' main vital function, O2 and CO2 transport and delivery, with consequences on peripheral tissue physiology and pathology. A high degree of deformability of RBCs is required to accommodate the size of micro-vessels with diameters significantly lower than RBCs. The potential therapeutic role of high-density lipoproteins (HDL) in the removal of cholesterol and its activity regarding maintenance of an optimal concentration of RBC membrane cholesterol have not been well investigated. On the contrary, the focus for HDL research has mainly been on the clearance of cholesterol accumulated in atherosclerotic macrophages and plaques. Since all interventions aiming at decreasing cardiovascular diseases by increasing the plasma level of HDL cholesterol have failed so far in large outcome studies, we reviewed the potential role of HDL to remove excess membrane cholesterol from RBC, especially in sickle cell disease (SCD). Indeed, abundant literature supports a consistent decrease in cholesterol transported by all plasma lipoproteins in SCD, in addition to HDL, low- (LDL) and very low-density lipoproteins (VLDL). Unexpectedly, these decreases in plasma were associated with an increase in RBC membrane cholesterol. The concentration and activity of the main enzyme involved in the removal of cholesterol and generation of large HDL particles-lecithin cholesterol ester transferase (LCAT)-are also significantly decreased in SCD. These observations might partially explain the decrease in RBC deformability, diminished gas exchange and tendency of RBCs to aggregate in SCD. We showed that incubation of RBC from SCD patients with human HDL or the HDL-mimetic peptide Fx5A improves the impaired RBC deformability and decreases intracellular reactive oxygen species levels. We propose that the main physiological role of HDL is to regulate the cholesterol/phospholipid ratio (C/PL), which is fundamental to the transport of oxygen and its delivery to peripheral tissues.
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Affiliation(s)
| | - Elie Nader
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, 69007 Lyon, France
| | - Anne Perez
- Hartis Pharma SA Nyon, 1260 Nyon, Switzerland
| | | | | | - Alan Remaley
- National Institutes of Health, Bethesda, MD 20814, USA
| | | | - Philippe Connes
- Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, 69007 Lyon, France
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12
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Tan Y, Hu X, Hou Y, Chu Z. Emerging Diamond Quantum Sensing in Bio-Membranes. MEMBRANES 2022; 12:957. [PMID: 36295716 PMCID: PMC9609316 DOI: 10.3390/membranes12100957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Bio-membranes exhibit complex but unique mechanical properties as communicative regulators in various physiological and pathological processes. Exposed to a dynamic micro-environment, bio-membranes can be seen as an intricate and delicate system. The systematical modeling and detection of their local physical properties are often difficult to achieve, both quantitatively and precisely. The recent emerging diamonds hosting quantum defects (i.e., nitrogen-vacancy (NV) center) demonstrate intriguing optical and spin properties, together with their outstanding photostability and biocompatibility, rendering them ideal candidates for biological applications. Notably, the extraordinary spin-based sensing enable the measurements of localized nanoscale physical quantities such as magnetic fields, electrical fields, temperature, and strain. These nanoscale signals can be optically read out precisely by simple optical microscopy systems. Given these exclusive properties, NV-center-based quantum sensors can be widely applied in exploring bio-membrane-related features and the communicative chemical reaction processes. This review mainly focuses on NV-based quantum sensing in bio-membrane fields. The attempts of applying NV-based quantum sensors in bio-membranes to investigate diverse physical and chemical events such as membrane elasticity, phase change, nanoscale bio-physical signals, and free radical formation are fully overviewed. We also discuss the challenges and future directions of this novel technology to be utilized in bio-membranes.
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Affiliation(s)
- Yayin Tan
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Xinhao Hu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Yong Hou
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Zhiqin Chu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
- Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong 999077, China
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13
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Drechsel V, Schneebauer G, Fiechtner B, Cutler CP, Pelster B. Aquaporin expression and cholesterol content in eel swimbladder tissue. JOURNAL OF FISH BIOLOGY 2022; 100:609-618. [PMID: 34882794 PMCID: PMC9302985 DOI: 10.1111/jfb.14973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 05/08/2023]
Abstract
Leakiness of the swimbladder wall of teleost fishes must be prevented to avoid diffusional loss of gases out of the swimbladder. Guanine incrustation as well as high concentrations of cholesterol in swimbladder membranes in midwater and deep-sea fish has been connected to a reduced gas permeability of the swimbladder wall. On the contrary, the swimbladder is filled by diffusion of gases, mainly oxygen and CO2 , from the blood and the gas gland cells into the swimbladder lumen. In swimbladder tissue of the zebrafish and the Japanese eel, aquaporin mRNA has been detected, and the aquaporin protein has been considered important for the diffusion of water, which may accidentally be gulped by physostome fish when taking an air breath. In the present study, the expression of two aquaporin 1 genes (Aqp1aa and Aqp1ab) in the swimbladder tissue of the European eel, a functional physoclist fish, was assessed using immunohistochemistry, and the expression of both genes was detected in endothelial cells of swimbladder capillaries as well as in basolateral membranes of gas gland cells. In addition, Aqp1ab was present in apical membranes of swimbladder gas gland cells. The authors also found high concentrations of cholesterol in these membranes, which were several fold higher than in muscle tissue membranes. In yellow eels the cholesterol concentration exceeded the concentration detected in silver eel swimbladder membranes. The authors suggest that aquaporin 1 in swimbladder gas gland cells and endothelial cells facilitates CO2 diffusion into the blood, enhancing the switch-on of the Root effect, which is essential for the secretion of oxygen into the swimbladder. It may also facilitate CO2 diffusion into the swimbladder lumen along the partial gradient established by CO2 production in gas gland cells. Cholesterol has been shown to reduce the gas permeability of membranes and thus could contribute to the gas tightness of swimbladder membranes, which is essential to avoid diffusional loss of gas out of the swimbladder.
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Affiliation(s)
- Victoria Drechsel
- Institute of ZoologyUniversity of InnsbruckInnsbruckAustria
- Center for Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Gabriel Schneebauer
- Institute of ZoologyUniversity of InnsbruckInnsbruckAustria
- Center for Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | - Birgit Fiechtner
- Institute of ZoologyUniversity of InnsbruckInnsbruckAustria
- Center for Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
| | | | - Bernd Pelster
- Institute of ZoologyUniversity of InnsbruckInnsbruckAustria
- Center for Molecular BiosciencesUniversity of InnsbruckInnsbruckAustria
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14
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Provensi G, Nocentini A, Passani MB, Blandina P, Supuran CT. Activation of carbonic anhydrase isoforms involved in modulation of emotional memory and cognitive disorders with histamine agonists, antagonists and derivatives. J Enzyme Inhib Med Chem 2021; 36:719-726. [PMID: 33648390 PMCID: PMC7928026 DOI: 10.1080/14756366.2021.1891051] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 12/20/2022] Open
Abstract
Carbonic anhydrases (CAs, EC 4.2.1.1) activators were shown to be involved in memory enhancement and learning in animal models of cognition. Here we investigated the CA activating effects of a large series of histamine based compounds, including histamine receptors (H1R - H4R) agonists, antagonists and other derivatives of this autacoid. CA activators may be thus useful for improving cognition as well as in diverse therapeutic areas (phobias, obsessive-compulsive disorder, generalised anxiety, post-traumatic stress disorders), for which activation of this enzyme was recently shown to be involved.
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Affiliation(s)
- Gustavo Provensi
- Department of NEUROFARBA, University of Florence, Section of Pharmacology and Toxicology, Firenze, Italy
| | - Alessio Nocentini
- Department of NEUROFARBA, University of Florence, Section of Pharmacology and Toxicology, Firenze, Italy
| | - Maria Beatrice Passani
- Department of Health Science, University of Florence, Section of Clinical Pharmacology and Oncology, Firenze, Italy
| | - Patrizio Blandina
- Department of NEUROFARBA, University of Florence, Section of Pharmacology and Toxicology, Firenze, Italy
| | - Claudiu T. Supuran
- Department of NEUROFARBA, University of Florence, Section of Pharmacology and Toxicology, Firenze, Italy
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15
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Al-Samir S, Prill M, Supuran CT, Gros G, Endeward V. CO 2 permeability of the rat erythrocyte membrane and its inhibition. J Enzyme Inhib Med Chem 2021; 36:1602-1606. [PMID: 34261373 PMCID: PMC8282279 DOI: 10.1080/14756366.2021.1952194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
We have studied the CO2 permeability of the erythrocyte membrane of the rat using a mass spectrometric method that employs 18 O-labelled CO2. The method yields, in addition, the intraerythrocytic carbonic anhydrase activity and the membrane HCO3- permeability. For normal rat erythrocytes, we find at 37 °C a CO2 permeability of 0.078 ± 0.015 cm/s, an intracellular carbonic anhydrase activity of 64,100, and a bicarbonate permeability of 2.1 × 10-3 cm/s. We studied whether the rat erythrocyte membrane possesses protein CO2 channels similar to the human red cell membrane by applying the potential CO2 channel inhibitors pCMBS, Dibac, phloretin, and DIDS. Phloretin and DIDS were able to reduce the CO2 permeability by up to 50%. Since these effects cannot be attributed to the lipid part of the membrane, we conclude that the rat erythrocyte membrane is equipped with protein CO2 channels that are responsible for at least 50% of its CO2 permeability.
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Affiliation(s)
- Samer Al-Samir
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Maximilian Prill
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Claudiu T Supuran
- Neurofarba Department, Section of Pharmaceutical and Nutritional Sciences, University of Florence, Florence, Italy
| | - Gerolf Gros
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Volker Endeward
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, Hannover, Germany
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16
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Kazokaitė-Adomaitienė J, Becker HM, Smirnovienė J, Dubois LJ, Matulis D. Experimental Approaches to Identify Selective Picomolar Inhibitors for Carbonic Anhydrase IX. Curr Med Chem 2021; 28:3361-3384. [PMID: 33138744 DOI: 10.2174/0929867327666201102112841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Carbonic anhydrases (CAs) regulate pH homeostasis via the reversible hydration of CO2, thereby emerging as essential enzymes for many vital functions. Among 12 catalytically active CA isoforms in humans, CA IX has become a relevant therapeutic target because of its role in cancer progression. Only two CA IX inhibitors have entered clinical trials, mostly due to low affinity and selectivity properties. OBJECTIVE The current review presents the design, development, and identification of the selective nano- to picomolar CA IX inhibitors VD11-4-2, VR16-09, and VD12-09. METHODS AND RESULTS Compounds were selected from our database, composed of over 400 benzensulfonamides, synthesized at our laboratory, and tested for their binding to 12 human CAs. Here we discuss the CA CO2 hydratase activity/inhibition assay and several biophysical techniques, such as fluorescent thermal shift assay and isothermal titration calorimetry, highlighting their contribution to the analysis of compound affinity and structure- activity relationships. To obtain sufficient amounts of recombinant CAs for inhibitor screening, several gene cloning and protein purification strategies are presented, including site-directed CA mutants, heterologous CAs from Xenopus oocytes, and native endogenous CAs. The cancer cell-based methods, such as clonogenicity, extracellular acidification, and mass spectrometric gas-analysis are reviewed, confirming nanomolar activities of lead inhibitors in intact cancer cells. CONCLUSIONS Novel CA IX inhibitors are promising derivatives for in vivo explorations. Furthermore, the simultaneous targeting of several proteins involved in proton flux upon tumor acidosis and the disruption of transport metabolons might improve cancer management.
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Affiliation(s)
- Justina Kazokaitė-Adomaitienė
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Joana Smirnovienė
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Ludwig J Dubois
- The M-Lab, Department of Precision Medicine, GROW - School for Oncology and Developmental Biology, Maastricht University, Netherlands
| | - Daumantas Matulis
- Department of Biothermodynamics and Drug Design, Institute of Biotechnology, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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17
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Michenkova M, Taki S, Blosser MC, Hwang HJ, Kowatz T, Moss FJ, Occhipinti R, Qin X, Sen S, Shinn E, Wang D, Zeise BS, Zhao P, Malmstadt N, Vahedi-Faridi A, Tajkhorshid E, Boron WF. Carbon dioxide transport across membranes. Interface Focus 2021; 11:20200090. [PMID: 33633837 PMCID: PMC7898146 DOI: 10.1098/rsfs.2020.0090] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 12/30/2022] Open
Abstract
Carbon dioxide (CO2) movement across cellular membranes is passive and governed by Fick's law of diffusion. Until recently, we believed that gases cross biological membranes exclusively by dissolving in and then diffusing through membrane lipid. However, the observation that some membranes are CO2 impermeable led to the discovery of a gas molecule moving through a channel; namely, CO2 diffusion through aquaporin-1 (AQP1). Later work demonstrated CO2 diffusion through rhesus (Rh) proteins and NH3 diffusion through both AQPs and Rh proteins. The tetrameric AQPs exhibit differential selectivity for CO2 versus NH3 versus H2O, reflecting physico-chemical differences among the small molecules as well as among the hydrophilic monomeric pores and hydrophobic central pores of various AQPs. Preliminary work suggests that NH3 moves through the monomeric pores of AQP1, whereas CO2 moves through both monomeric and central pores. Initial work on AQP5 indicates that it is possible to create a metal-binding site on the central pore's extracellular face, thereby blocking CO2 movement. The trimeric Rh proteins have monomers with hydrophilic pores surrounding a hydrophobic central pore. Preliminary work on the bacterial Rh homologue AmtB suggests that gas can diffuse through the central pore and three sets of interfacial clefts between monomers. Finally, initial work indicates that CO2 diffuses through the electrogenic Na/HCO3 cotransporter NBCe1. At least in some cells, CO2-permeable proteins could provide important pathways for transmembrane CO2 movements. Such pathways could be amenable to cellular regulation and could become valuable drug targets.
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Affiliation(s)
- Marie Michenkova
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Sara Taki
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Matthew C. Blosser
- Mork Family Department of Chemical Engineering & Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Hyea J. Hwang
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Thomas Kowatz
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Fraser. J. Moss
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Xue Qin
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Soumyo Sen
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Eric Shinn
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Dengke Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Brian S. Zeise
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Pan Zhao
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Noah Malmstadt
- Mork Family Department of Chemical Engineering & Materials Science, University of Southern California, Los Angeles, CA, USA
| | - Ardeschir Vahedi-Faridi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Walter F. Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, USA
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18
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Al-Samir S, Itel F, Hegermann J, Gros G, Tsiavaliaris G, Endeward V. O 2 permeability of lipid bilayers is low, but increases with membrane cholesterol. Cell Mol Life Sci 2021; 78:7649-7662. [PMID: 34694438 PMCID: PMC8629883 DOI: 10.1007/s00018-021-03974-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 09/06/2021] [Accepted: 10/12/2021] [Indexed: 11/18/2022]
Abstract
Oxygen on its transport route from lung to tissue mitochondria has to cross several cell membranes. The permeability value of membranes for O2 (PO2), although of fundamental importance, is controversial. Previous studies by mostly indirect methods diverge between 0.6 and 125 cm/s. Here, we use a most direct approach by observing transmembrane O2 fluxes out of 100 nm liposomes at defined transmembrane O2 gradients in a stopped-flow system. Due to the small size of the liposomes intra- as well as extraliposomal diffusion processes do not affect the overall kinetics of the O2 release process. We find, for cholesterol-free liposomes, the unexpectedly low PO2 value of 0.03 cm/s at 35 °C. This PO2 would present a serious obstacle to O2 entering or leaving the erythrocyte. Cholesterol turns out to be a novel major modifier of PO2, able to increase PO2 by an order of magnitude. With a membrane cholesterol of 45 mol% as it occurs in erythrocytes, PO2 rises to 0.2 cm/s at 35 °C. This PO2 is just sufficient to ensure complete O2 loading during passage of erythrocytes through the lung's capillary bed under the conditions of rest as well as maximal exercise.
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Affiliation(s)
- Samer Al-Samir
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Fabian Itel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstr. 5, CH-9014, St. Gallen, Switzerland
| | - Jan Hegermann
- Abteilung Funktionelle und Angewandte Anatomie, Elektronenmikroskopie 8840, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Gerolf Gros
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany.
| | - Georgios Tsiavaliaris
- Abteilung Biophysikalische Chemie 4350, Medizinische Hochschule Hannover, 30625, Hannover, Germany
| | - Volker Endeward
- AG Vegetative Physiologie 4220, Zentrum Physiologie, Medizinische Hochschule Hannover, 30625, Hannover, Germany
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19
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Blanco-Ameijeiras S, Stoll HM, Zhang H, Hopkinson BM. Influence of Temperature and CO 2 On Plasma-membrane Permeability to CO 2 and HCO 3- in the Marine Haptophytes Emiliania huxleyi and Calcidiscus leptoporus (Prymnesiophyceae). JOURNAL OF PHYCOLOGY 2020; 56:1283-1294. [PMID: 32418211 DOI: 10.1111/jpy.13017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/28/2020] [Indexed: 06/11/2023]
Abstract
Membrane permeabilities to CO2 and HCO3- constrain the function of CO2 concentrating mechanisms that algae use to supply inorganic carbon for photosynthesis. In diatoms and green algae, plasma membranes are moderately to highly permeable to CO2 but effectively impermeable to HCO3- . Here, CO2 and HCO3- membrane permeabilities were measured using an 18 O-exchange technique on two species of haptophyte algae, Emiliania huxleyi and Calcidiscus leptoporus, which showed that the plasma membranes of these species are also highly permeable to CO2 (0.006-0.02 cm · s-1 ) but minimally permeable to HCO3- . Increased temperature and CO2 generally increased CO2 membrane permeabilities in both species, possibly due to changes in lipid composition or CO2 channel proteins. Changes in CO2 membrane permeabilities showed no association with the density of calcium carbonate coccoliths surrounding the cell, which could potentially impede passage of compounds. Haptophyte plasma-membrane permeabilities to CO2 were somewhat lower than those of diatoms but generally higher than membrane permeabilities of green algae. One caveat of these measurements is that the model used to interpret 18 O-exchange data assumes that carbonic anhydrase, which catalyzes 18 O-exchange, is homogeneously distributed in the cell. The implications of this assumption were tested using a two-compartment model with an inhomogeneous distribution of carbonic anhydrase to simulate 18 O-exchange data and then inferring plasma-membrane CO2 permeabilities from the simulated data. This analysis showed that the inferred plasma-membrane CO2 permeabilities are minimal estimates but should be quite accurate under most conditions.
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Affiliation(s)
| | - Heather M Stoll
- Department of Earth Sciences, ETH Zurich, Sonnegstrasse 5, Zurich, 8092, Switzerland
| | - Hongrui Zhang
- Department of Earth Sciences, ETH Zurich, Sonnegstrasse 5, Zurich, 8092, Switzerland
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Brian M Hopkinson
- Department of Marine Sciences, University of Georgia, Athens, Georgia, 30602, USA
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20
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Moss FJ, Mahinthichaichan P, Lodowski DT, Kowatz T, Tajkhorshid E, Engel A, Boron WF, Vahedi-Faridi A. Aquaporin-7: A Dynamic Aquaglyceroporin With Greater Water and Glycerol Permeability Than Its Bacterial Homolog GlpF. Front Physiol 2020; 11:728. [PMID: 32695023 PMCID: PMC7339978 DOI: 10.3389/fphys.2020.00728] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 06/04/2020] [Indexed: 12/27/2022] Open
Abstract
Xenopus oocytes expressing human aquaporin-7 (AQP7) exhibit greater osmotic water permeability and 3H-glycerol uptake vs. those expressing the bacterial glycerol facilitator GlpF. AQP7-expressing oocytes exposed to increasing extracellular [glycerol] under isosmolal conditions exhibit increasing swelling rates, whereas GlpF-expressing oocytes do not swell at all. To provide a structural basis for these observed physiological differences, we performed X-ray crystallographic structure determination of AQP7 and molecular-dynamics simulations on AQP7 and GlpF. The structure reveals AQP7 tetramers containing two monomers with 3 glycerols, and two monomers with 2 glycerols in the pore. In contrast to GlpF, no glycerol is bound at the AQP7 selectivity filter (SF), comprising residues F74, G222, Y223, and R229. The AQP7 SF is resolved in its closed state because F74 blocks the passage of small solutes. Molecular dynamics simulations demonstrate that F74 undergoes large and rapid conformational changes, allowing glycerol molecules to permeate without orientational restriction. The more rigid GlpF imposes orientational constraints on glycerol molecules passing through the SF. Moreover, GlpF-W48 (analogous to AQP7-F74) undergoes rare but long-lasting conformational changes that block the pore to H2O and glycerol.
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Affiliation(s)
- Fraser J. Moss
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Paween Mahinthichaichan
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - David T. Lodowski
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Thomas Kowatz
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Emad Tajkhorshid
- Department of Biochemistry, Center for Biophysics and Quantitative Biology, and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Andreas Engel
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Walter F. Boron
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Department of Medicine, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Ardeschir Vahedi-Faridi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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21
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Roosterman D, Cottrell GS. Astrocytes and neurons communicate via a monocarboxylic acid shuttle. AIMS Neurosci 2020; 7:94-106. [PMID: 32607414 PMCID: PMC7321766 DOI: 10.3934/neuroscience.2020007] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023] Open
Abstract
Since formulation of the Astrocyte-Neuron Lactate Shuttle (ANLS) hypothesis in 1994, the hypothesis has provoked criticism and debate. Our review does not criticise, but rather integrates experimental data characterizing proton-linked monocarboxylate transporters (MCTs) into the ANLS. MCTs have wide substrate specificity and are discussed to be in protein complex with a proton donor (PD). We particularly focus on the proton-driven transfer of l-lactic acid (l-lacH) and pyruvic acid (pyrH), were PDs link MCTs to a flow of energy. The precise nature of the PD predicts the activity and catalytic direction of MCTs. By doing so, we postulate that the MCT4·phosphoglycerate kinase complex exports and at the same time in the same astrocyte, MCT1·carbonic anhydrase II complex imports monocarboxylic acids. Similarly, neuronal MCT2 preferentially imports pyrH. The repertoire of MCTs in astrocytes and neurons allows them to communicate via monocarboxylic acids. A change in imported pyrH/l-lacH ratio in favour of l-lacH encodes signals stabilizing the transit of glucose from astrocytes to neurons. The presented astrocyte neuron communication hypothesis has the potential to unite the community by suggesting that the exchange of monocarboxylic acids paves the path of glucose provision.
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Affiliation(s)
- Dirk Roosterman
- Ruhr Universität Bochum, LWL-Hospital of Psychiatry, Bochum, Germany
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22
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Becker HM. Carbonic anhydrase IX and acid transport in cancer. Br J Cancer 2020; 122:157-167. [PMID: 31819195 PMCID: PMC7051959 DOI: 10.1038/s41416-019-0642-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/29/2019] [Accepted: 10/22/2019] [Indexed: 02/07/2023] Open
Abstract
Alterations in tumour metabolism and acid/base regulation result in the formation of a hostile environment, which fosters tumour growth and metastasis. Acid/base homoeostasis in cancer cells is governed by the concerted interplay between carbonic anhydrases (CAs) and various transport proteins, which either mediate proton extrusion or the shuttling of acid/base equivalents, such as bicarbonate and lactate, across the cell membrane. Accumulating evidence suggests that some of these transporters interact both directly and functionally with CAIX to form a protein complex coined the 'transport metabolon'. Transport metabolons formed between bicarbonate transporters and CAIX require CA catalytic activity and have a function in cancer cell migration and invasion. Another type of transport metabolon is formed by CAIX and monocarboxylate transporters. In this complex, CAIX functions as a proton antenna for the transporter, which drives the export of lactate and protons from the cell. Since CAIX is almost exclusively expressed in cancer cells, these transport metabolons might serve as promising targets to interfere with tumour pH regulation and energy metabolism. This review provides an overview of the current state of research on the function of CAIX in tumour acid/base transport and discusses how CAIX transport metabolons could be exploited in modern cancer therapy.
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Affiliation(s)
- Holger M Becker
- Institute of Physiological Chemistry, University of Veterinary Medicine Hannover, D-30559, Hannover, Germany.
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23
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Kitchen P, Salman MM, Pickel SU, Jennings J, Törnroth-Horsefield S, Conner MT, Bill RM, Conner AC. Water channel pore size determines exclusion properties but not solute selectivity. Sci Rep 2019; 9:20369. [PMID: 31889130 PMCID: PMC6937295 DOI: 10.1038/s41598-019-56814-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 12/12/2019] [Indexed: 11/24/2022] Open
Abstract
Aquaporins (AQPs) are a ubiquitous family of transmembrane water channel proteins. A subgroup of AQP water channels also facilitates transmembrane diffusion of small, polar solutes. A constriction within the pore, the aromatic/arginine (ar/R) selectivity filter, is thought to control solute permeability: previous studies on single representative water channel proteins suggest narrow channels conduct water, whilst wider channels permit passage of solutes. To assess this model of selectivity, we used mutagenesis, permeability measurements and in silico comparisons of water-specific as well as glycerol-permeable human AQPs. Our studies show that single amino acid substitutions in the selectivity filters of AQP1, AQP4 and AQP3 differentially affect glycerol and urea permeability in an AQP-specific manner. Comparison between in silico-calculated channel cross-sectional areas and in vitro permeability measurements suggests that selectivity filter cross-sectional area predicts urea but not glycerol permeability. Our data show that substrate discrimination in water channels depends on a complex interplay between the solute, pore size, and polarity, and that using single water channel proteins as representative models has led to an underestimation of this complexity.
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Affiliation(s)
- Philip Kitchen
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK.
| | - Mootaz M Salman
- Department of Cell Biology, Harvard Medical School, and Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Simone U Pickel
- Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Jordan Jennings
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | | | - Matthew T Conner
- School of Biology, Chemistry and Forensic Science, University of Wolverhampton, Wulfruna St, Wolverhampton, UK
| | - Roslyn M Bill
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham, B4 7ET, UK
| | - Alex C Conner
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
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24
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Alishahi M, Kamali R. A novel molecular dynamics study of CO 2 permeation through aquaporin-5. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:151. [PMID: 31773315 DOI: 10.1140/epje/i2019-11912-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 10/24/2019] [Indexed: 06/10/2023]
Abstract
Aquaporins (AQPs) are protein channels which facilitate rapid water permeation across cell membrane. The AQPs are very vital for biological organs, as their malfunction causes severe diseases in human body. A particular family of AQPs, that is AQP5, has a significant role in lung fluid transport due to submucosal glands structure. However, it has not been yet well understood whether these protein channels can conduct gas molecules. Here, Molecular Dynamics (MD) simulations are used to investigate the CO2 permeability and diffusion in AQP5 during a 40-nanosecond period. For the first time, equilibrium and Steered MD (SMD) are used to simulate self and force-induced diffusion of CO2 molecules across AQP5 and POPE lipid bilayer. According to PMFs profile associated to CO2 permeation, the hydrophobic central pore provides a more suitable pathway for gas molecules compared to other AQP5 channels. Although CO2 molecules can also permeate across AQP5 water channels, the rate of CO2 permeation through four channels of the AQP5 monomers is much lower than the central pore. The rate of CO2 permeation through four AQP5 water channels is even lower than CO2 diffusion through POPE lipid membrane. The results reported in this investigation demonstrate that MD simulations of human AQP5 provide valuable insights into the gas permeation mechanism for both the equilibrium self-diffusion, and quasi-equilibrium condition.
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Affiliation(s)
- Marzieh Alishahi
- Department of Mechanical Engineering, Shiraz University, Shiraz, Iran
| | - Reza Kamali
- Department of Mechanical Engineering, Shiraz University, Shiraz, Iran.
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25
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Abstract
Spontaneous solute and solvent permeation through membranes is of vital importance to human life, be it gas exchange in red blood cells, metabolite excretion, drug/toxin uptake, or water homeostasis. Knowledge of the underlying molecular mechanisms is the sine qua non of every functional assignment to membrane transporters. The basis of our current solubility diffusion model was laid by Meyer and Overton. It correlates the solubility of a substance in an organic phase with its membrane permeability. Since then, a wide range of studies challenging this rule have appeared. Commonly, the discrepancies have their origin in ill-used measurement approaches, as we demonstrate on the example of membrane CO2 transport. On the basis of the insight that scanning electrochemical microscopy offered into solute concentration distributions in immediate membrane vicinity of planar membranes, we analyzed the interplay between chemical reactions and diffusion for solvent transport, weak acid permeation, and enzymatic reactions adjacent to membranes. We conclude that buffer reactions must also be considered in spectroscopic investigations of weak acid transport in vesicular suspensions. The evaluation of energetic contributions to membrane translocation of charged species demonstrates the compatibility of the resulting membrane current with the solubility diffusion model. A local partition coefficient that depends on membrane penetration depth governs spontaneous membrane translocation of both charged and uncharged molecules. It is determined not only by the solubility in an organic phase but also by other factors like cholesterol concentration and intrinsic electric membrane potentials.
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Affiliation(s)
- Christof Hannesschlaeger
- From the Institute of Biophysics , Johannes Kepler University Linz , Gruberstrasse 40 , 4020 Linz , Austria
| | - Andreas Horner
- From the Institute of Biophysics , Johannes Kepler University Linz , Gruberstrasse 40 , 4020 Linz , Austria
| | - Peter Pohl
- From the Institute of Biophysics , Johannes Kepler University Linz , Gruberstrasse 40 , 4020 Linz , Austria
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26
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Akaishi T, Onishi E, Abe M, Toyama H, Ishizawa K, Kumagai M, Kubo R, Nakashima I, Aoki M, Yamauchi M, Ishii T. The human central nervous system discharges carbon dioxide and lactic acid into the cerebrospinal fluid. Fluids Barriers CNS 2019; 16:8. [PMID: 30922337 PMCID: PMC6440017 DOI: 10.1186/s12987-019-0128-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 03/15/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The central nervous system was previously thought to draw oxygen and nutrition from the arteries and discharge carbon dioxide and other metabolic wastes into the venous system. At present, the functional role of cerebrospinal fluid in brain metabolism is not fully known. METHODS In this prospective observational study, we performed gas analysis on venous blood and cerebrospinal fluid simultaneously acquired from 16 consecutive preoperative patients without any known neurological disorders. RESULTS The carbon dioxide partial pressure (pCO2) (p < 0.0001) and lactic acid level (p < 0.001) in the cerebrospinal fluid were significantly higher than those in the peripheral venous blood, suggesting that a considerable proportion of metabolic carbon dioxide and lactic acid is discharged from the central nervous system into the cerebrospinal fluid. The oxygen partial pressure (pO2) was much higher in the cerebrospinal fluid than in the venous blood, corroborating the conventional theory of cerebrospinal fluid circulatory dynamics. The pCO2 of the cerebrospinal fluid showed a strong negative correlation with age (R = - 0.65, p = 0.0065), but the other studied variables did not show significant correlation with age. CONCLUSION Carbon dioxide and lactic acid are discharged into the circulating cerebrospinal fluid, as well as into the venules. The level of carbon dioxide in the cerebrospinal fluid significantly decreased with age.
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Affiliation(s)
- Tetsuya Akaishi
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Seiryo-machi 1-1, Aoba-ku, Sendai, Miyagi, 980-8574, Japan. .,Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan.
| | - Eiko Onishi
- Department of Anesthesiology and Perioperative Medicine, Tohoku University Hospital, Sendai, Japan
| | - Michiaki Abe
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Seiryo-machi 1-1, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.,Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Hiroaki Toyama
- Department of Anesthesiology and Perioperative Medicine, Tohoku University Hospital, Sendai, Japan
| | - Kota Ishizawa
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Seiryo-machi 1-1, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.,Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
| | - Michio Kumagai
- Department of Anesthesiology and Perioperative Medicine, Tohoku University Hospital, Sendai, Japan
| | - Ryosuke Kubo
- Department of Anesthesiology and Perioperative Medicine, Tohoku University Hospital, Sendai, Japan
| | - Ichiro Nakashima
- Department of Neurology, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Masanori Yamauchi
- Department of Anesthesiology and Perioperative Medicine, Tohoku University Hospital, Sendai, Japan
| | - Tadashi Ishii
- Department of Education and Support for Regional Medicine, Tohoku University Hospital, Seiryo-machi 1-1, Aoba-ku, Sendai, Miyagi, 980-8574, Japan
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27
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Roosterman D, Meyerhof W, Cottrell GS. Proton Transport Chains in Glucose Metabolism: Mind the Proton. Front Neurosci 2018; 12:404. [PMID: 29962930 PMCID: PMC6014028 DOI: 10.3389/fnins.2018.00404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 05/25/2018] [Indexed: 01/11/2023] Open
Abstract
The Embden-Meyerhof-Parnas (EMP) pathway comprises eleven cytosolic enzymes interacting to metabolize glucose to lactic acid [CH3CH(OH)COOH]. Glycolysis is largely considered as the conversion of glucose to pyruvate (CH3COCOO-). We consider glycolysis to be a cellular process and as such, transporters mediating glucose uptake and lactic acid release and enable the flow of metabolites through the cell, must be considered as part of the EMP pathway. In this review, we consider the flow of metabolites to be coupled to a flow of energy that is irreversible and sufficient to form ordered structures. This latter principle is highlighted by discussing that lactate dehydrogenase (LDH) complexes irreversibly reduce pyruvate/H+ to lactate [CH3CH(OH)COO-], or irreversibly catalyze the opposite reaction, oxidation of lactate to pyruvate/H+. However, both LDH complexes are considered to be driven by postulated proton transport chains. Metabolism of glucose to two lactic acids is introduced as a unidirectional, continuously flowing pathway. In an organism, cell membrane-located proton-linked monocarboxylate transporters catalyze the final step of glycolysis, the release of lactic acid. Consequently, both pyruvate and lactate are discussed as intermediate products of glycolysis and substrates of regulated crosscuts of the glycolytic flow.
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Affiliation(s)
| | - Wolfgang Meyerhof
- Center for Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
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28
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Arias-Hidalgo M, Al-Samir S, Gros G, Endeward V. Cholesterol is the main regulator of the carbon dioxide permeability of biological membranes. Am J Physiol Cell Physiol 2018; 315:C137-C140. [PMID: 29874108 DOI: 10.1152/ajpcell.00139.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We present here a compilation of membrane CO2 permeabilities (Pco2) for various cell types from the literature. Pco2 values vary over more than two orders of magnitude. Relating Pco2 to the cholesterol content of the membranes shows that, with the exception of red blood cells, it is essentially membrane cholesterol that determines the value of Pco2. Thus, the observed strong modulation of Pco2 in the majority of membranes is caused by cholesterol rather than gas channels.
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Affiliation(s)
- Mariela Arias-Hidalgo
- Institut für Molekular und Zellphysiologie, AG Vegetative Physiologie, Medizinische Hochschule Hannover, Hannover , Germany
| | - Samer Al-Samir
- Institut für Molekular und Zellphysiologie, AG Vegetative Physiologie, Medizinische Hochschule Hannover, Hannover , Germany
| | - Gerolf Gros
- Institut für Molekular und Zellphysiologie, AG Vegetative Physiologie, Medizinische Hochschule Hannover, Hannover , Germany
| | - Volker Endeward
- Institut für Molekular und Zellphysiologie, AG Vegetative Physiologie, Medizinische Hochschule Hannover, Hannover , Germany
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29
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Laloux T, Junqueira B, Maistriaux LC, Ahmed J, Jurkiewicz A, Chaumont F. Plant and Mammal Aquaporins: Same but Different. Int J Mol Sci 2018; 19:E521. [PMID: 29419811 PMCID: PMC5855743 DOI: 10.3390/ijms19020521] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 02/06/2023] Open
Abstract
Aquaporins (AQPs) constitute an ancient and diverse protein family present in all living organisms, indicating a common ancient ancestor. However, during evolution, these organisms appear and evolve differently, leading to different cell organizations and physiological processes. Amongst the eukaryotes, an important distinction between plants and animals is evident, the most conspicuous difference being that plants are sessile organisms facing ever-changing environmental conditions. In addition, plants are mostly autotrophic, being able to synthesize carbohydrates molecules from the carbon dioxide in the air during the process of photosynthesis, using sunlight as an energy source. It is therefore interesting to analyze how, in these different contexts specific to both kingdoms of life, AQP function and regulation evolved. This review aims at highlighting similarities and differences between plant and mammal AQPs. Emphasis is given to the comparison of isoform numbers, their substrate selectivity, the regulation of the subcellular localization, and the channel activity.
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Affiliation(s)
- Timothée Laloux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Bruna Junqueira
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Laurie C Maistriaux
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Jahed Ahmed
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - Agnieszka Jurkiewicz
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
| | - François Chaumont
- Institut des Sciences de la Vie, Université catholique de Louvain, Croix du Sud 4-L7.07.14, B-1348 Louvain-la Neuve, Belgium.
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30
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Flexas J, Cano FJ, Carriquí M, Coopman RE, Mizokami Y, Tholen D, Xiong D. CO2 Diffusion Inside Photosynthetic Organs. THE LEAF: A PLATFORM FOR PERFORMING PHOTOSYNTHESIS 2018. [DOI: 10.1007/978-3-319-93594-2_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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CO₂ Permeability of Biological Membranes and Role of CO₂ Channels. MEMBRANES 2017; 7:membranes7040061. [PMID: 29064458 PMCID: PMC5746820 DOI: 10.3390/membranes7040061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 01/09/2023]
Abstract
We summarize here, mainly for mammalian systems, the present knowledge of (a) the membrane CO₂ permeabilities in various tissues; (b) the physiological significance of the value of the CO₂ permeability;
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32
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Arias-Hidalgo M, Al-Samir S, Weber N, Geers-Knörr C, Gros G, Endeward V. CO 2 permeability and carbonic anhydrase activity of rat cardiomyocytes. Acta Physiol (Oxf) 2017; 221:115-128. [PMID: 28429509 DOI: 10.1111/apha.12887] [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: 01/11/2017] [Revised: 04/11/2017] [Accepted: 04/14/2017] [Indexed: 11/30/2022]
Abstract
AIM To determine the CO2 permeability (PCO2 ) of plasma membranes of cardiomyocytes. These cells were chosen because heart possesses the highest rate of O2 consumption/CO2 production in the body. METHODS Cardiomyocytes were isolated from rat hearts using the Langendorff technique. Cardiomyocyte suspensions exhibited a vitality of 2-14% and were studied by the previously described mass spectrometric 18 O-exchange technique deriving PCO2 . We showed by mass spectrometry and by carbonic anhydrase (CA) staining that non-vital cardiomyocytes are free of CA and thus do not contribute to the mass spectrometric signal, which is determined exclusively by the fully functional vital cardiomyocytes. RESULTS Lysed cardiomyocytes yielded an intracellular CA activity for vital cells of 5070; that is, the rate of CO2 hydration inside the cell is accelerated 5071-fold. Using this number, analyses of the mass spectrometric recordings from cardiomyocyte suspensions yield a PCO2 of 0.10 cm s-1 (SD ± 0.06, n = 15) at 37 °C. CONCLUSION In comparison with the PCO2 of other cells, this value is quite high and about identical to that of the human red cell membrane. As no major protein CO2 channels such as aquaporins 1 and 4 are present in rat cardiac sarcolemma, the high PCO2 of this membrane is likely due to its low cholesterol content of about 0.2 (mol cholesterol)·(mol total membrane lipids)-1 . Previous work predicted a PCO2 of ≥0.1 cm s-1 from this level of cholesterol. We conclude that the low cholesterol establishes a PCO2 high enough to render the membrane resistance to CO2 diffusion almost negligible, even under conditions of maximal O2 consumption of the heart.
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Affiliation(s)
- M. Arias-Hidalgo
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
| | - S. Al-Samir
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
| | - N. Weber
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
| | - C. Geers-Knörr
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
| | - G. Gros
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
| | - V. Endeward
- Molekular- und Zellphysiologie and AG Vegetative Physiologie; Medizinische Hochschule Hannover; Hannover Germany
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33
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Friscourt F, Badaut J. Aquaporins through the brain in health and disease: From water to gas movements. J Neurosci Res 2017; 96:177-179. [PMID: 28960397 DOI: 10.1002/jnr.24155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/22/2017] [Accepted: 08/22/2017] [Indexed: 01/05/2023]
Affiliation(s)
- Frédéric Friscourt
- CNRS UMR 5287, INCIA, University of Bordeaux, Bordeaux, France.,Institut Européen de Chimie et Biologie, University of Bordeaux, Pessac, France
| | - Jerome Badaut
- CNRS UMR 5287, INCIA, University of Bordeaux, Bordeaux, France.,Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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34
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Saboe PO, Rapisarda C, Kaptan S, Hsiao YS, Summers SR, De Zorzi R, Dukovski D, Yu J, de Groot BL, Kumar M, Walz T. Role of Pore-Lining Residues in Defining the Rate of Water Conduction by Aquaporin-0. Biophys J 2017; 112:953-965. [PMID: 28297654 DOI: 10.1016/j.bpj.2017.01.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/22/2016] [Accepted: 01/26/2017] [Indexed: 11/19/2022] Open
Abstract
Compared to other aquaporins (AQPs), lens-specific AQP0 is a poor water channel, and its permeability was reported to be pH-dependent. To date, most water conduction studies on AQP0 were performed on protein expressed in Xenopus oocytes, and the results may therefore also reflect effects introduced by the oocytes themselves. Experiments with purified AQP0 reconstituted into liposomes are challenging because the water permeability of AQP0 is only slightly higher than that of pure lipid bilayers. By reconstituting high amounts of AQP0 and using high concentrations of cholesterol to reduce the permeability of the lipid bilayer, we improved the signal-to-noise ratio of water permeability measurements on AQP0 proteoliposomes. Our measurements show that mutation of two pore-lining tyrosine residues, Tyr-23 and Tyr-149 in sheep AQP0, to the corresponding residues in the high-permeability water channel AQP1 have additive effects and together increase the water permeability of AQP0 40-fold to a level comparable to that of AQP1. Molecular dynamics simulations qualitatively support these experimental findings and suggest that mutation of Tyr-23 changes the pore profile at the gate formed by residue Arg-187.
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Affiliation(s)
- Patrick O Saboe
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Chiara Rapisarda
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Shreyas Kaptan
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Yu-Shan Hsiao
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Samantha R Summers
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Rita De Zorzi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Danijela Dukovski
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Jiaheng Yu
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania
| | - Bert L de Groot
- Computational Biomolecular Dynamics Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Manish Kumar
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania.
| | - Thomas Walz
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts.
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35
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Groszmann M, Osborn HL, Evans JR. Carbon dioxide and water transport through plant aquaporins. PLANT, CELL & ENVIRONMENT 2017; 40:938-961. [PMID: 27739588 DOI: 10.1111/pce.12844] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/01/2016] [Accepted: 09/22/2016] [Indexed: 05/25/2023]
Abstract
Aquaporins are channel proteins that function to increase the permeability of biological membranes. In plants, aquaporins are encoded by multigene families that have undergone substantial diversification in land plants. The plasma membrane intrinsic proteins (PIPs) subfamily of aquaporins is of particular interest given their potential to improve plant water relations and photosynthesis. Flowering plants have between 7 and 28 PIP genes. Their expression varies with tissue and cell type, through development and in response to a variety of factors, contributing to the dynamic and tissue specific control of permeability. There are a growing number of PIPs shown to act as water channels, but those altering membrane permeability to CO2 are more limited. The structural basis for selective substrate specificities has not yet been resolved, although a few key amino acid positions have been identified. Several regions important for dimerization, gating and trafficking are also known. PIP aquaporins assemble as tetramers and their properties depend on the monomeric composition. PIPs control water flux into and out of veins and stomatal guard cells and also increase membrane permeability to CO2 in mesophyll and stomatal guard cells. The latter increases the effectiveness of Rubisco and can potentially influence transpiration efficiency.
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Affiliation(s)
- Michael Groszmann
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - Hannah L Osborn
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - John R Evans
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
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36
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Zhao M, Tan HT, Scharwies J, Levin K, Evans JR, Tyerman SD. Association between water and carbon dioxide transport in leaf plasma membranes: assessing the role of aquaporins. PLANT, CELL & ENVIRONMENT 2017; 40:789-801. [PMID: 27620674 DOI: 10.1111/pce.12830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/05/2016] [Accepted: 09/07/2016] [Indexed: 05/24/2023]
Abstract
The role of some aquaporins as CO2 permeable channels has been controversial. Low CO2 permeability of plant membranes has been criticized because of unstirred layers and other limitations. Here we measured both water and CO2 permeability (Pos , PCO2 ) using stopped flow on plasma membrane vesicles (pmv) isolated from Pisum sativum (pea) and Arabidopsis thaliana leaves. We excluded the chemical limitation of carbonic anhydrase (CA) in the vesicle acidification technique for PCO2 using different temperatures and CA concentrations. Unstirred layers were excluded based on small vesicle size and the positive correlation between vesicle diameter and PCO2 . We observed high aquaporin activity (Pos 0.06 to 0.22 cm s-1 ) for pea pmv based on all the criteria for their function using inhibitors and temperature dependence. Inhibitors of Pos did not alter PCO2 . PCO2 ranged from 0.001 to 0.012 cm s-1 (mean 0.0079 + 0.0007 cm s-1 ) with activation energy of 30.2 kJ mol-1 . Intrinsic variation between pmv batches from normally grown or stressed plants revealed a weak (R2 = 0.27) positive linear correlation between Pos and PCO2 . Despite the low PCO2 , aquaporins may facilitate CO2 transport across plasma membranes, but probably via a different pathway than for water.
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Affiliation(s)
- Manchun Zhao
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Hwei-Ting Tan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Johannes Scharwies
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - Kara Levin
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
| | - John R Evans
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Stephen D Tyerman
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, 5064, Australia
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37
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Tolleter D, Chochois V, Poiré R, Price GD, Badger MR. Measuring CO2 and HCO3- permeabilities of isolated chloroplasts using a MIMS-18O approach. JOURNAL OF EXPERIMENTAL BOTANY 2017. [PMID: 28637277 PMCID: PMC5853524 DOI: 10.1093/jxb/erx188] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
To support photosynthetic CO2 fixation by Rubisco, the chloroplast must be fed with inorganic carbon in the form of CO2 or bicarbonate. However, the mechanisms allowing the rapid passage of this gas and this charged molecule through the bounding membranes of the chloroplast envelope are not yet completely elucidated. We describe here a method allowing us to measure the permeability of these two molecules through the chloroplast envelope using a membrane inlet mass spectrometer and 18O-labelled inorganic carbon. We established that the internal stromal carbonic anhydrase activity is not limiting for this technique, and precisely measured the chloroplast surface area and permeability values for CO2 and bicarbonate. This was performed on chloroplasts from several plant species, with values ranging from 2.3 × 10-4 m s-1 to 8 × 10-4 m s-1 permeability for CO2 and 1 × 10-8 m s-1 for bicarbonate. We were able to apply our method to chloroplasts from an Arabidopsis aquaporin mutant, and this showed that CO2 permeability was reduced 50% in the mutant compared with the wild-type reference.
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Affiliation(s)
- Dimitri Tolleter
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
- Correspondence:
| | - Vincent Chochois
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Richard Poiré
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - G Dean Price
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Murray R Badger
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
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38
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Rodriguez-Grande B, Konsman JP. Gas Diffusion in the CNS. J Neurosci Res 2017; 96:207-218. [PMID: 28504343 DOI: 10.1002/jnr.24077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/23/2017] [Accepted: 04/10/2017] [Indexed: 12/21/2022]
Abstract
Gases have been long known to have essential physiological functions in the CNS such as respiration or regulation of vascular tone. Since gases have been classically considered to freely diffuse, research in gas biology has so far focused on mechanisms of gas synthesis and gas reactivity, rather than gas diffusion and transport. However, the discovery of gas pores during the last two decades and the characterization of diverse diffusion patterns through different membranes has raised the possibility that modulation of gas diffusion is also a physiologically relevant parameter. Here we review the means of gas movement into and within the brain through "free" diffusion and gas pores, notably aquaporins, discussing the role that gas diffusion may play in the modulation of gas function. We highlight how diffusion is relevant to neuronal signaling, volume transmission, and cerebrovascular control in the case of NO, one of the most extensively studied gases. We point out how facilitated transport can be especially relevant for gases with low permeability in lipid membranes like NH3 and discuss the possible implications of NH3 -permeable channels in physiology and hyperammonemic encephalopathy. We identify novel research questions about how modulation of gas diffusion could intervene in CNS pathologies. This emerging area of research can provide novel and interesting insights in the field of gas biology.
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39
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Talbot K, Kwong RWM, Gilmour KM, Perry SF. The water channel aquaporin-1a1 facilitates movement of CO₂ and ammonia in zebrafish (Danio rerio) larvae. ACTA ACUST UNITED AC 2017; 218:3931-40. [PMID: 26677259 DOI: 10.1242/jeb.129759] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The present study tested the hypothesis that zebrafish (Danio rerio) aquaporin-1a1 (AQP1a1) serves as a multi-functional channel for the transfer of the small gaseous molecules, CO2 and ammonia, as well as water, across biological membranes. Zebrafish embryos were microinjected with a translation-blocking morpholino oligonucleotide targeted to AQP1a1. Knockdown of AQP1a1 significantly reduced rates of CO2 and ammonia excretion, as well as water fluxes, in larvae at 4 days post fertilization (dpf). Because AQP1a1 is expressed both in ionocytes present on the body surface and in red blood cells, the haemolytic agent phenylhydrazine was used to distinguish between the contributions of AQP1a1 to gas transfer in these two locations. Phenylhydrazine treatment had no effect on AQP1a1-linked excretion of CO2 or ammonia, providing evidence that AQP1a1 localized to the yolk sac epithelium, rather than red blood cell AQP1a1, is the major site of CO2 and ammonia movements. The possibility that AQP1a1 and the rhesus glycoprotein Rhcg1, which also serves as a dual CO2 and ammonia channel, act in concert to facilitate CO2 and ammonia excretion was explored. Although knockdown of each protein did not affect the abundance of mRNA and protein of the other protein under control conditions, impairment of ammonia excretion by chronic exposure to high external ammonia triggered a significant increase in the abundance of AQP1a1 mRNA and protein in 4 dpf larvae experiencing Rhcg1 knockdown. Collectively, these results suggest that AQP1a1 in zebrafish larvae facilitates the movement of CO2 and ammonia, as well as water, in a physiologically relevant fashion.
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Affiliation(s)
- Krystle Talbot
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Raymond W M Kwong
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Kathleen M Gilmour
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Steve F Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
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40
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Laporte-Uribe JA. The role of dissolved carbon dioxide in both the decline in rumen pH and nutritional diseases in ruminants. Anim Feed Sci Technol 2016. [DOI: 10.1016/j.anifeedsci.2016.06.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Martínez-Ballesta MDC, Carvajal M. Mutual Interactions between Aquaporins and Membrane Components. FRONTIERS IN PLANT SCIENCE 2016; 7:1322. [PMID: 27625676 PMCID: PMC5003842 DOI: 10.3389/fpls.2016.01322] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/18/2016] [Indexed: 05/08/2023]
Abstract
In recent years, a number of studies have been focused on the structural evaluation of protein complexes in order to get mechanistic insights into how proteins communicate at the molecular level within the cell. Specific sites of protein-aquaporin interaction have been evaluated and new forms of regulation of aquaporins described, based on these associations. Heterotetramerizations of aquaporin isoforms are considered as novel regulatory mechanisms for plasma membrane (PIPs) and tonoplast (TIPs) proteins, influencing their intrinsic permeability and trafficking dynamics in the adaptive response to changing environmental conditions. However, protein-protein interaction is an extensive theme that is difficult to tackle and new methodologies are being used to study the physical interactions involved. Bimolecular fluorescence complementation and the identification of cross-linked peptides based on tandem mass spectra, that are complementary to other methodologies such as heterologous expression, co-precipitation assays or confocal fluorescence microscopy, are discussed in this review. The chemical composition and the physical characteristics of the lipid bilayer also influence many aspects of membrane aquaporins, including their functionality. The molecular driving forces stabilizing the positions of the lipids around aquaporins could define their activity, thereby altering the conformational properties. Therefore, an integrative approach to the relevance of the membrane-aquaporin interaction to different processes related to plant cell physiology is provided. Finally, it is described how the interactions between aquaporins and copolymer matrixes or biological compounds offer an opportunity for the functional incorporation of aquaporins into new biotechnological advances.
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Affiliation(s)
| | - Micaela Carvajal
- Plant Nutrition Department, Aquaporins Group, Centro de Edafología y Biología Aplicada del Segura-Consejo Superior de Investigaciones Científicas (CEBAS-CSIC)Murcia, Spain
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42
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Al-Samir S, Goossens D, Cartron JP, Nielsen S, Scherbarth F, Steinlechner S, Gros G, Endeward V. Maximal Oxygen Consumption Is Reduced in Aquaporin-1 Knockout Mice. Front Physiol 2016; 7:347. [PMID: 27559317 PMCID: PMC4978734 DOI: 10.3389/fphys.2016.00347] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 07/29/2016] [Indexed: 12/01/2022] Open
Abstract
We have measured maximal oxygen consumption (V˙O2,max) of mice lacking one or two of the established mouse red-cell CO2 channels AQP1, AQP9, and Rhag. We intended to study whether these proteins, by acting as channels for O2, determine O2 exchange in the lung and in the periphery. We found that V˙O2,max as determined by the Helox technique is reduced by ~16%, when AQP1 is knocked out, but not when AQP9 or Rhag are lacking. This figure holds for animals respiring normoxic as well as hypoxic gas mixtures. To see whether the reduction of V˙O2,max is due to impaired O2 uptake in the lung, we measured carotid arterial O2 saturation (SO2) by pulse oximetry. Neither under normoxic (inspiratory O2 21%) nor under hypoxic conditions (11% O2) is there a difference in SO2 between AQP1null and WT mice, suggesting that AQP1 is not critical for O2 uptake in the lung. The fact that the % reduction of V˙O2,max is identical in normoxia and hypoxia indicates moreover that the limitation of V˙O2,max is not due to an O2 diffusion problem, neither in the lung nor in the periphery. Instead, it appears likely that AQP1null animals exhibit a reduced V˙O2,max due to the reduced wall thickness and muscle mass of the left ventricles of their hearts, as reported previously. We conclude that very likely the properties of the hearts of AQP1 knockout mice cause a reduced maximal cardiac output and thus cause a reduced V˙O2,max, which constitutes a new phenotype of these mice.
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Affiliation(s)
- Samer Al-Samir
- Vegetative Physiologie 4220, Abt. Molekular-und Zellphysiologie, Medizinische Hochschule Hannover Hannover, Germany
| | - Dominique Goossens
- Institut National de la Transfusion Sanguine-Institut National de la Santé et de la Recherche Médicale UMR_S1134 Paris, France
| | - Jean-Pierre Cartron
- Institut National de la Transfusion Sanguine-Institut National de la Santé et de la Recherche Médicale UMR_S1134 Paris, France
| | - Søren Nielsen
- Biomedicine, Department Health Science and Technology, Aalborg University Aalborg, Denmark
| | - Frank Scherbarth
- Institut für Zoologie, Tierärztliche Hochschule Hannover Hannover, Germany
| | | | - Gerolf Gros
- Vegetative Physiologie 4220, Abt. Molekular-und Zellphysiologie, Medizinische Hochschule Hannover Hannover, Germany
| | - Volker Endeward
- Vegetative Physiologie 4220, Abt. Molekular-und Zellphysiologie, Medizinische Hochschule Hannover Hannover, Germany
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43
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Modulating intracellular acidification by regulating the incubation time of proton caged compounds. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:565-71. [DOI: 10.1007/s00249-016-1122-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 02/05/2016] [Accepted: 02/20/2016] [Indexed: 10/22/2022]
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44
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Abstract
It is difficult to distinguish influx and efflux of inorganic C in photosynthesizing tissues; this article examines what is known and where there are gaps in knowledge. Irreversible decarboxylases produce CO2, and CO2 is the substrate/product of enzymes that act as carboxylases and decarboxylases. Some irreversible carboxylases use CO2; others use HCO3(-). The relative role of permeation through the lipid bilayer versus movement through CO2-selective membrane proteins in the downhill, non-energized, movement of CO2 is not clear. Passive permeation explains most CO2 entry, including terrestrial and aquatic organisms with C3 physiology and biochemistry, terrestrial C4 plants and all crassulacean acid metabolism (CAM) plants, as well as being part of some mechanisms of HCO3(-) use in CO2 concentrating mechanism (CCM) function, although further work is needed to test the mechanism in some cases. However, there is some evidence of active CO2 influx at the plasmalemma of algae. HCO3(-) active influx at the plasmalemma underlies all cyanobacterial and some algal CCMs. HCO3(-) can also enter some algal chloroplasts, probably as part of a CCM. The high intracellular CO2 and HCO3(-) pools consequent upon CCMs result in leakage involving CO2, and occasionally HCO3(-). Leakage from cyanobacterial and microalgal CCMs involves up to half, but sometimes more, of the gross inorganic C entering in the CCM; leakage from terrestrial C4 plants is lower in most environments. Little is known of leakage from other organisms with CCMs, though given the leakage better-examined organisms, leakage occurs and increases the energetic cost of net carbon assimilation.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK†, and School of Plant Biology, University of Western Australia, M084, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, VIC 3800, Australia
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45
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Hulikova A, Vaughan-Jones RD, Niederer SA, Swietach P. CrossTalk opposing view: Physiological CO2 exchange does not normally depend on membrane channels. J Physiol 2015; 593:5029-32. [PMID: 26568197 PMCID: PMC4666997 DOI: 10.1113/jp270013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 09/22/2015] [Indexed: 11/08/2022] Open
Affiliation(s)
- Alzbeta Hulikova
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford, OX1 3PT, UK
| | - Richard D Vaughan-Jones
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford, OX1 3PT, UK
| | - Steven A Niederer
- Bioengineering Department, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, SE1 7EH, UK
| | - Pawel Swietach
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, Oxford University, Parks Road, Oxford, OX1 3PT, UK
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46
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Li L, Wang H, Gago J, Cui H, Qian Z, Kodama N, Ji H, Tian S, Shen D, Chen Y, Sun F, Xia Z, Ye Q, Sun W, Flexas J, Dong H. Harpin Hpa1 Interacts with Aquaporin PIP1;4 to Promote the Substrate Transport and Photosynthesis in Arabidopsis. Sci Rep 2015; 5:17207. [PMID: 26607179 PMCID: PMC4660436 DOI: 10.1038/srep17207] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/27/2015] [Indexed: 12/12/2022] Open
Abstract
Harpin proteins produced by plant-pathogenic Gram-negative bacteria are the venerable player in regulating bacterial virulence and inducing plant growth and defenses. A major gap in these effects is plant sensing linked to cellular responses, and plant sensor for harpin Hpa1 from rice bacterial blight pathogen points to plasma membrane intrinsic protein (PIP). Here we show that Arabidopsis AtPIP1;4 is a plasma membrane sensor of Hpa1 and plays a dual role in plasma membrane permeability of CO2 and H2O. In particular, AtPIP1;4 mediates CO2 transport with a substantial contribute to photosynthesis and further increases this function upon interacting with Hpa1 at the plasma membrane. As a result, leaf photosynthesis rates are increased and the plant growth is enhanced in contrast to the normal process without Hpa1-AtPIP1;4 interaction. Our findings demonstrate the first case that plant sensing of a bacterial harpin protein is connected with photosynthetic physiology to regulate plant growth.
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Affiliation(s)
- Liang Li
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Hao Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Jorge Gago
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Haiying Cui
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Zhengjiang Qian
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Naomi Kodama
- Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, Tsukuba 305-8604, Japan
| | - Hongtao Ji
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Shan Tian
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Dan Shen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanjuan Chen
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Fengli Sun
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhonglan Xia
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qing Ye
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Wei Sun
- Institute of Grassland Science, Northeast Normal University and National Ministry of Education Key Laboratory of Vegetation Ecology, Changchun 130024, China
| | - Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears, Palma de Mallorca, Illes Balears 07122, Spain
| | - Hansong Dong
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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Cooper GJ, Occhipinti R, Boron WF. CrossTalk proposal: Physiological CO2 exchange can depend on membrane channels. J Physiol 2015; 593:5025-8. [PMID: 26568076 DOI: 10.1113/jp270059] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/22/2015] [Indexed: 12/18/2022] Open
Affiliation(s)
- Gordon J Cooper
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Rossana Occhipinti
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.,Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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48
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Kitchen P, Day RE, Salman MM, Conner MT, Bill RM, Conner AC. Beyond water homeostasis: Diverse functional roles of mammalian aquaporins. Biochim Biophys Acta Gen Subj 2015; 1850:2410-21. [PMID: 26365508 DOI: 10.1016/j.bbagen.2015.08.023] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 08/25/2015] [Accepted: 08/30/2015] [Indexed: 01/02/2023]
Abstract
BACKGROUND Aquaporin (AQP) water channels are best known as passive transporters of water that are vital for water homeostasis. SCOPE OF REVIEW AQP knockout studies in whole animals and cultured cells, along with naturally occurring human mutations suggest that the transport of neutral solutes through AQPs has important physiological roles. Emerging biophysical evidence suggests that AQPs may also facilitate gas (CO2) and cation transport. AQPs may be involved in cell signalling for volume regulation and controlling the subcellular localization of other proteins by forming macromolecular complexes. This review examines the evidence for these diverse functions of AQPs as well their physiological relevance. MAJOR CONCLUSIONS As well as being crucial for water homeostasis, AQPs are involved in physiologically important transport of molecules other than water, regulation of surface expression of other membrane proteins, cell adhesion, and signalling in cell volume regulation. GENERAL SIGNIFICANCE Elucidating the full range of functional roles of AQPs beyond the passive conduction of water will improve our understanding of mammalian physiology in health and disease. The functional variety of AQPs makes them an exciting drug target and could provide routes to a range of novel therapies.
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Affiliation(s)
- Philip Kitchen
- Molecular Organisation and Assembly in Cells Doctoral Training Centre, University of Warwick, Coventry CV4 7AL, UK
| | - Rebecca E Day
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK
| | - Mootaz M Salman
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK
| | - Matthew T Conner
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK
| | - Roslyn M Bill
- School of Life & Health Sciences and Aston Research Centre for Healthy Ageing, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Alex C Conner
- Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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49
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Gaitzsch J, Huang X, Voit B. Engineering Functional Polymer Capsules toward Smart Nanoreactors. Chem Rev 2015; 116:1053-93. [DOI: 10.1021/acs.chemrev.5b00241] [Citation(s) in RCA: 300] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jens Gaitzsch
- Department
of Chemistry, University College London, London WC1H 0AJ, United Kingdom
- Department
of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Basel-Stadt, Switzerland
| | - Xin Huang
- School
of Chemical Engineering and Technology, Harbin Institute of Technology, 150001 Harbin, Heilongjiang, China
| | - Brigitte Voit
- Leibniz-Institut fuer Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Saxony, Germany
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50
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Abstract
In this review, we provide a brief synopsis of the evolution and functional diversity of the aquaporin gene superfamily in prokaryotic and eukaryotic organisms. Based upon the latest data, we discuss the expanding list of molecules shown to permeate the central pore of aquaporins, and the unexpected diversity of water channel genes in Archaea and Bacteria. We further provide new insight into the origin by horizontal gene transfer of plant glycerol-transporting aquaporins (NIPs), and the functional co-option and gene replacement of insect glycerol transporters. Finally, we discuss the origins of four major grades of aquaporins in Eukaryota, together with the increasing repertoires of aquaporins in vertebrates.
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Affiliation(s)
- Roderick Nigel Finn
- Department of Biology, Bergen High Technology Centre, University of Bergen, Norway; Institute of Marine Research, Nordnes, 5817 Bergen, Norway; and
| | - Joan Cerdà
- Institut de Recerca i Tecnologia Agroalimentàries (IRTA)-Institut de Ciències del Mar, Consejo Superior de Investigaciones Científicas (CSIC), 08003 Barcelona, Spain
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