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Bettamin L, Mathieu F, Marty FH, Blatche MC, Gonzalez-Dunia D, Suberbielle E, Larrieu G. Real-Time and High-Resolution Monitoring of Neuronal Electrical Activity and pH Variations Based on the Co-Integration of Nanoelectrodes and Chem-FinFETs. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309055. [PMID: 38552225 DOI: 10.1002/smll.202309055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 03/18/2024] [Indexed: 07/05/2024]
Abstract
Developing new approaches amenable to the measurement of neuronal physiology in real-time is a very active field of investigation, as it will offer improved methods to assess the impact of diverse insults on neuronal homeostasis. Here, the development of an in vitro bio platform is reported which can record the electrical activity of cultured primary rat cortical neurons with extreme sensitivity, while simultaneously tracking the localized changes in the pH of the culture medium. This bio platform features passive vertical nanoprobes with ultra-high signal resolution (several mV amplitude ranges) and Chem-FinFETs (pH sensitivity of sub-0.1 pH units), covering an area as little as a neuronal soma. These multi-sensing units are arranged in an array to probe both chemically and electrically an equivalent surface of ≈ 0.5 mm2. A homemade setup is also developed which allows recording of multiplexed data in real-time (10 ps range) from the active chem-sensors and passive electrodes and which is used to operate the platform. Finally, a proof-of-concept is presented for a neuro-relevant application, by investigating the effect on neuronal activity of Amyloid beta oligomers, the main toxic peptide in Alzheimer's Disease, which reveals that exposure to amyloid beta oligomers modify the amplitude, but not the frequency, of neuronal firing, without any detectable changes in pH values along this process.
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Affiliation(s)
- Luca Bettamin
- LAAS-CNRS, CNRS, Université de Toulouse, Toulouse, 31031, France
- INFINITY, INSERM, CNRS, Université de Toulouse, Toulouse, 31031, France
| | - Fabrice Mathieu
- LAAS-CNRS, CNRS, Université de Toulouse, Toulouse, 31031, France
| | - Florent H Marty
- INFINITY, INSERM, CNRS, Université de Toulouse, Toulouse, 31031, France
| | | | | | - Elsa Suberbielle
- INFINITY, INSERM, CNRS, Université de Toulouse, Toulouse, 31031, France
| | - Guilhem Larrieu
- LAAS-CNRS, CNRS, Université de Toulouse, Toulouse, 31031, France
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Thompson P, Vilkelyte V, Woronkowicz M, Tavakoli M, Skopinski P, Roberts H. Adenylyl Cyclase in Ocular Health and Disease: A Comprehensive Review. BIOLOGY 2024; 13:445. [PMID: 38927325 PMCID: PMC11200476 DOI: 10.3390/biology13060445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/12/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024]
Abstract
Adenylyl cyclases (ACs) are a group of enzymes that convert adenosine-5'-triphosphate (ATP) to cyclic adenosine 3',5' monophosphate (cAMP), a vital and ubiquitous signalling molecule in cellular responses to hormones and neurotransmitters. There are nine transmembrane (tmAC) forms, which have been widely studied; however, the tenth, soluble AC (sAC) is less extensively characterised. The eye is one of the most metabolically active sites in the body, where sAC has been found in abundance, making it a target for novel therapeutics and biomarking. In the cornea, AC plays a role in endothelial cell function, which is vital in maintaining stromal dehydration, and therefore, clarity. In the retina, AC has been implicated in axon cell growth and survival. As these cells are irreversibly damaged in glaucoma and injury, this molecule may provide focus for future therapies. Another potential area for glaucoma management is the source of aqueous humour production, the ciliary body, where AC has also been identified. Furthering the understanding of lacrimal gland function is vital in managing dry eye disease, a common and debilitating condition. sAC has been linked to tear production and could serve as a therapeutic target. Overall, ACs are an exciting area of study in ocular health, offering multiple avenues for future medical therapies and diagnostics. This review paper explores the diverse roles of ACs in the eye and their potential as targets for innovative treatments.
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Affiliation(s)
- Polly Thompson
- West of England Eye Unit, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK;
| | - Virginija Vilkelyte
- University of Exeter Medical School, St Luke’s Campus, University of Exeter, Exeter EX1 2HZ, UK
| | - Malgorzata Woronkowicz
- NDDH, Royal Devon University Healthcare NHS Foundation Trust, Barnstaple EX31 4JB, UK;
- Moorfields Eye Hospital NHS Foundation Trust, 162 City Road, London EC1V 2PD, UK
| | - Mitra Tavakoli
- University of Exeter Medical School, St Luke’s Campus, University of Exeter, Exeter EX1 2HZ, UK
| | - Piotr Skopinski
- Department of Ophthalmology, SPKSO Ophthalmic University Hospital, Medical University of Warsaw, 00-576 Warsaw, Poland
- Department of Histology and Embryology, Medical University of Warsaw, 02-004 Warsaw, Poland
| | - Harry Roberts
- West of England Eye Unit, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK;
- University of Exeter Medical School, St Luke’s Campus, University of Exeter, Exeter EX1 2HZ, UK
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Potter AE, White CR, Marshall DJ. Per capita sperm metabolism is density dependent. J Exp Biol 2024; 227:jeb246674. [PMID: 38380562 PMCID: PMC11006396 DOI: 10.1242/jeb.246674] [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: 08/29/2023] [Accepted: 02/08/2024] [Indexed: 02/22/2024]
Abstract
From bacteria to metazoans, higher density populations have lower per capita metabolic rates than lower density populations. The negative covariance between population density and metabolic rate is thought to represent a form of adaptive metabolic plasticity. A relationship between density and metabolism was actually first noted 100 years ago, and was focused on spermatozoa; even then, it was postulated that adaptive plasticity drove this pattern. Since then, contemporary studies of sperm metabolism specifically assume that sperm concentration has no effect on metabolism and that sperm metabolic rates show no adaptive plasticity. We did a systematic review to estimate the relationship between sperm aerobic metabolism and sperm concentration, for 198 estimates spanning 49 species, from protostomes to humans from 88 studies. We found strong evidence that per capita metabolic rates are concentration dependent: both within and among species, sperm have lower metabolisms in dense ejaculates, but increase their metabolism when diluted. On average, a 10-fold decrease in sperm concentration increased per capita metabolic rate by 35%. Metabolic plasticity in sperm appears to be an adaptive response, whereby sperm maximize their chances of encountering eggs.
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Affiliation(s)
- Ashley E. Potter
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Craig R. White
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Dustin J. Marshall
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
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Nohesara S, Abdolmaleky HM, Thiagalingam S. Potential for New Therapeutic Approaches by Targeting Lactate and pH Mediated Epigenetic Dysregulation in Major Mental Diseases. Biomedicines 2024; 12:457. [PMID: 38398057 PMCID: PMC10887322 DOI: 10.3390/biomedicines12020457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
Multiple lines of evidence have shown that lactate-mediated pH alterations in the brains of patients with neuropsychiatric diseases such as schizophrenia (SCZ), Alzheimer's disease (AD) and autism may be attributed to mitochondrial dysfunction and changes in energy metabolism. While neuronal activity is associated with reduction in brain pH, astrocytes are responsible for rebalancing the pH to maintain the equilibrium. As lactate level is the main determinant of brain pH, neuronal activities are impacted by pH changes due to the binding of protons (H+) to various types of proteins, altering their structure and function in the neuronal and non-neuronal cells of the brain. Lactate and pH could affect diverse types of epigenetic modifications, including histone lactylation, which is linked to histone acetylation and DNA methylation. In this review, we discuss the importance of pH homeostasis in normal brain function, the role of lactate as an essential epigenetic regulatory molecule and its contributions to brain pH abnormalities in neuropsychiatric diseases, and shed light on lactate-based and pH-modulating therapies in neuropsychiatric diseases by targeting epigenetic modifications. In conclusion, we attempt to highlight the potentials and challenges of translating lactate-pH-modulating therapies to clinics for the treatment of neuropsychiatric diseases.
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Affiliation(s)
- Shabnam Nohesara
- Department of Medicine (Biomedical Genetics), Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA;
| | - Hamid Mostafavi Abdolmaleky
- Department of Medicine (Biomedical Genetics), Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA;
- Nutrition/Metabolism Laboratory, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Sam Thiagalingam
- Department of Medicine (Biomedical Genetics), Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA;
- Department of Pathology & Laboratory Medicine, Boston University Chobanian and Avedisian School of Medicine, Boston, MA 02118, USA
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5
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Keitel L, Braun K, Finger M, Kosfeld U, Yordanov S, Büchs J. Carbon dioxide and trace oxygen concentrations impact growth and product formation of the gut bacterium Phocaeicola vulgatus. BMC Microbiol 2023; 23:391. [PMID: 38062358 PMCID: PMC10701953 DOI: 10.1186/s12866-023-03127-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 11/17/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The promising yet barely investigated anaerobic species Phocaeicola vulgatus (formerly Bacteroides vulgatus) plays a vital role for human gut health and effectively produces organic acids. Among them is succinate, a building block for high-value-added chemicals. Cultivating anaerobic bacteria is challenging, and a detailed understanding of P. vulgatus growth and metabolism is required to improve succinate production. One significant aspect is the influence of different gas concentrations. CO2 is required for the growth of P. vulgatus. However, it is a greenhouse gas that should not be wasted. Another highly interesting aspect is the sensitivity of P. vulgatus towards O2. In this work, the effects of varying concentrations of both gases were studied in the in-house developed Respiratory Activity MOnitoring System (RAMOS), which provides online monitoring of CO2, O2, and pressure under gassed conditions. The RAMOS was combined with a gas mixing system to test CO2 and O2 concentrations in a range of 0.25-15.0 vol% and 0.0-2.5 vol%, respectively. RESULTS Changing the CO2 concentration in the gas supply revealed a CO2 optimum of 3.0 vol% for total organic acid production and 15.0 vol% for succinate production. It was demonstrated that the organic acid composition changed depending on the CO2 concentration. Furthermore, unrestricted growth of P. vulgatus up to an O2 concentration of 0.7 vol% in the gas supply was proven. The viability decreased rapidly at concentrations larger than or equal to 1.3 vol% O2. CONCLUSIONS The study showed that P. vulgatus requires little CO2, has a distinct O2 tolerance and is therefore well suited for industrial applications.
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Affiliation(s)
- Laura Keitel
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Kristina Braun
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Maurice Finger
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Udo Kosfeld
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Stanislav Yordanov
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Jochen Büchs
- Chair of Biochemical Engineering (AVT.BioVT), RWTH Aachen University, Forckenbeckstraße 51, 52074, Aachen, Germany.
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6
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Villeda-Hernandez M, Baker BC, Romero C, Rossiter JM, Dicker MPM, Faul CFJ. Chemically Driven Oscillating Soft Pneumatic Actuation. Soft Robot 2023; 10:1159-1170. [PMID: 37384917 DOI: 10.1089/soro.2022.0168] [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: 07/01/2023] Open
Abstract
Pneumatic actuators are widely studied in soft robotics as they are facile, low cost, scalable, and robust and exhibit compliance similar to many systems found in nature. The challenge is to harness high energy density chemical and biochemical reactions that can generate sufficient pneumatic pressure to actuate soft systems in a controlled and ecologically compatible manner. This investigation evaluates the potential of chemical reactions as both positive and negative pressure sources for use in soft robotic pneumatic actuators. Considering the pneumatic actuation demands, the chemical mechanisms of the pressure sources, and the safety of the system, several gas evolution/consumption reactions are evaluated and compared. Furthermore, the novel coupling of both gas evolution and gas consumption reactions is discussed and evaluated for the design of oscillating systems, driven by the complementary evolution and consumption of carbon dioxide. Control over the speed of gas generation and consumption is achieved by adjusting the initial ratios of feed materials. Coupling the appropriate reactions with pneumatic soft-matter actuators has delivered autonomous cyclic actuation. The reversibility of these systems is demonstrated in a range of displacement experiments, and practical application is shown through a soft gripper that can move, pick up, and let go of objects. Our approach presents a significant step toward more autonomous, versatile soft robots driven by chemo-pneumatic actuators.
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Affiliation(s)
- Marcos Villeda-Hernandez
- School of Chemistry, University of Bristol, Bristol, United Kingdom
- School of Civil, Aerospace and Mechanical Engineering, University of Bristol, Bristol, United Kingdom
- Bristol Centre of Functional Nanomaterials, University of Bristol, Bristol, United Kingdom
| | - Benjamin C Baker
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Christian Romero
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
| | - Jonathan M Rossiter
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
- Bristol Robotics Laboratory, University of Bristol, Bristol, United Kingdom
| | - Michael P M Dicker
- School of Civil, Aerospace and Mechanical Engineering, University of Bristol, Bristol, United Kingdom
| | - Charl F J Faul
- School of Chemistry, University of Bristol, Bristol, United Kingdom
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7
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Zhao S, Chi L, Chen H. CEGA: a method for inferring natural selection by comparative population genomic analysis across species. Genome Biol 2023; 24:219. [PMID: 37789379 PMCID: PMC10548728 DOI: 10.1186/s13059-023-03068-8] [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: 07/26/2022] [Accepted: 09/20/2023] [Indexed: 10/05/2023] Open
Abstract
We developed maximum likelihood method for detecting positive selection or balancing selection using multilocus or genomic polymorphism and divergence data from two species. The method is especially useful for investigating natural selection in noncoding regions. Simulations demonstrate that the method outperforms existing methods in detecting both positive and balancing selection. We apply the method to population genomic data from human and chimpanzee. The list of genes identified under selection in the noncoding regions is prominently enriched in pathways related to the brain and nervous system. Therefore, our method will serve as a useful tool for comparative population genomic analysis.
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Affiliation(s)
- Shilei Zhao
- CAS Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
- School of Future Technology, College of Life Sciences and Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lianjiang Chi
- CAS Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China
- China National Center for Bioinformation, Beijing, 100101, China
| | - Hua Chen
- CAS Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, 100101, China.
- China National Center for Bioinformation, Beijing, 100101, China.
- School of Future Technology, College of Life Sciences and Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China.
- CAS Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, 650223, China.
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8
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Kottapurath Vijay A, Sharma VK, Meyerstein D. Overlooked Formation of Carbonate Radical Anions in the Oxidation of Iron(II) by Oxygen in the Presence of Bicarbonate. Angew Chem Int Ed Engl 2023; 62:e202309472. [PMID: 37439593 DOI: 10.1002/anie.202309472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/14/2023]
Abstract
Iron(II), (Fe(H2 O)6 2+ , (FeII ) participates in many reactions of natural and biological importance. It is critically important to understand the rates and the mechanism of FeII oxidation by dissolved molecular oxygen, O2 , under environmental conditions containing bicarbonate (HCO3 - ), which exists up to millimolar concentrations. In the absence and presence of HCO3 - , the formation of reactive oxygen species (O2 ⋅- , H2 O2 , and HO⋅) in FeII oxidation by O2 has been suggested. In contrast, our study demonstrates for the first time the rapid generation of carbonate radical anions (CO3 ⋅- ) in the oxidation of FeII by O2 in the presence of bicarbonate, HCO3 - . The rate of the formation of CO3 ⋅- may be expressed as d[CO3 ⋅- ]/dt=[FeII [[O2 ][HCO3 - ]2 . The formation of reactive species was investigated using 1 H nuclear magnetic resonance (1 H NMR) and gas chromatographic techniques. The study presented herein provides new insights into the reaction mechanism of FeII oxidation by O2 in the presence of bicarbonate and highlights the importance of considering the formation of CO3 ⋅- in the geochemical cycling of iron and carbon.
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Affiliation(s)
- Aswin Kottapurath Vijay
- Department of Chemical Sciences and The Radical Research Center, Ariel University, Ariel, 40700, Israel
- Chemistry Department, Ben-Gurion University, Beer-Sheva, 8410501, Israel
| | - Virender K Sharma
- Department of Environmental and Occupational Health, Texas A&M University, College Station, TX 77843, USA
| | - Dan Meyerstein
- Department of Chemical Sciences and The Radical Research Center, Ariel University, Ariel, 40700, Israel
- Chemistry Department, Ben-Gurion University, Beer-Sheva, 8410501, Israel
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9
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Woranush W, Moskopp ML, Noll T, Dieterich P. Quantifying and mathematical modelling of the influence of soluble adenylate cyclase on cell cycle in human endothelial cells with Bayesian inference. J Cell Mol Med 2022; 26:5887-5900. [DOI: 10.1111/jcmm.17611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 08/28/2022] [Accepted: 10/05/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Warunya Woranush
- Institut für Physiologie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden Dresden Germany
| | - Mats Leif Moskopp
- Institut für Physiologie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden Dresden Germany
- Vivantes Klinikum im Friedrichshain, Charité Academic Teaching Hospital, Klinik für Neurochirurgie Berlin Germany
| | - Thomas Noll
- Institut für Physiologie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden Dresden Germany
| | - Peter Dieterich
- Institut für Physiologie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden Dresden Germany
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10
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Martínez‐Crespo L, Valkenier H. Transmembrane Transport of Bicarbonate by Anion Receptors. Chempluschem 2022; 87:e202200266. [PMID: 36414387 PMCID: PMC9827909 DOI: 10.1002/cplu.202200266] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/13/2022] [Indexed: 01/31/2023]
Abstract
The development of synthetic anion transporters is motivated by their potential application as treatment for diseases that originate from deficient anion transport by natural proteins. Transport of bicarbonate is important for crucial biological functions such as respiration and digestion. Despite this biological relevance, bicarbonate transport has not been as widely studied as chloride transport. Herein we present an overview of the synthetic receptors that have been studied as bicarbonate transporters, together with the different assays used to perform transport studies in large unilamellar vesicles. We highlight the most active transporters and comment on the nature of the functional groups present in active and inactive compounds. We also address recent mechanistic studies that have revealed different processes that can lead to net transport of bicarbonate, as well as studies reported in cells and tissues, and comment on the key challenges for the further development of bicarbonate transporters.
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Affiliation(s)
- Luis Martínez‐Crespo
- Department of ChemistryUniversity of ManchesterOxford RoadManchesterM13 9PLUK,Manchester Institute of BiotechnologyUniversity of Manchester131 Princess StreetManchesterM1 7DNUK,Université Libre de Bruxelles (ULB) Engineering of Molecular NanoSystemsEcole polytechnique de BruxellesAvenue F.D. Roosevelt 50, CP165/64B-1050BrusselsBelgium
| | - Hennie Valkenier
- Université Libre de Bruxelles (ULB) Engineering of Molecular NanoSystemsEcole polytechnique de BruxellesAvenue F.D. Roosevelt 50, CP165/64B-1050BrusselsBelgium
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11
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Tunay D, Altinbas M, Ozkaya B. Usage of Source Separated Urine for the Biodiesel Production from Algal Biomass. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2022.108692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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12
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Boyne K, Corey DA, Zhao P, Lu B, Boron WF, Moss FJ, Kelley TJ. Carbonic anhydrase and soluble adenylate cyclase regulation of cystic fibrosis cellular phenotypes. Am J Physiol Lung Cell Mol Physiol 2022; 322:L333-L347. [PMID: 34986321 PMCID: PMC8858677 DOI: 10.1152/ajplung.00022.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Several aspects of the cell biology of cystic fibrosis (CF) epithelial cells are altered including impaired lipid regulation, disrupted intracellular transport, and impaired microtubule regulation. It is unclear how the loss of cystic fibrosis transmembrane conductance regulator (CFTR) function leads to these differences. It is hypothesized that the loss of CFTR function leads to altered regulation of carbonic anhydrase (CA) activity resulting in cellular phenotypic changes. In this study, it is demonstrated that CA2 protein expression is reduced in CF model cells, primary mouse nasal epithelial (MNE) cells, excised MNE tissue, and primary human nasal epithelial cells (P < 0.05). This corresponds to a decrease in CA2 RNA expression measured by qPCR as well as an overall reduction in CA activity in primary CF MNEs. The addition of CFTR-inhibitor-172 to WT MNE cells for ≥24 h mimics the significantly lower protein expression of CA2 in CF cells. Treatment of CF cells with l-phenylalanine (L-Phe), an activator of CA activity, restores endosomal transport through an effect on microtubule regulation in a manner dependent on soluble adenylate cyclase (sAC). This effect can be blocked with the CA2-selective inhibitor dorzolamide. These data suggest that the loss of CFTR function leads to the decreased expression of CA2 resulting in the downstream cell signaling alterations observed in CF.
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Affiliation(s)
- Kathleen Boyne
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Deborah A Corey
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Pan Zhao
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Binyu Lu
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States.,Department of Medicine and Department of Biochemistry, Case Western Reserve University, Cleveland, OH, United States
| | - Fraser J Moss
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Thomas J Kelley
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
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13
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Merrells RJ, Madon SB, Chivers PT, Fournier PA. Nausea after Repeated Sprints: Is Lactic Acidosis Really the Culprit? Med Sci Sports Exerc 2021; 53:1865-1872. [PMID: 34398059 DOI: 10.1249/mss.0000000000002667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Nausea caused by exhaustive sprinting is associated with high lactate ([La-]) and hydrogen ion concentrations ([H+]) and fall in blood pCO2, thus raising the issue of whether there is a causal link between nausea and these variables. For this reason, this study aimed to determine whether interspersing repeated sprints (RS) with periods of active, compared with passive, recovery results in lower levels of both nausea and changes in [La-], [H+], and pCO2. METHODS Twelve male participants completed two separate sessions comprising four 30-s sprints separated by 20 min of either active (AR; cycling at 40% V˙O2peak) or passive recovery (PR). At 6 and 18 min of each recovery period, nausea was assessed via a visual analog scale (VAS), and blood samples were collected to measure [La-], [H+], and pCO2. RESULTS RS significantly increased VAS score in both AR (P < 0.001) and PR (P < 0.01). After the first sprint, VAS was higher than preexercise in only AR (P < 0.01). AR was associated with lower VAS, [La-], [H+], and higher pCO2 (all P = 0.001) compared with PR after sprints 2-4. Linear mixed modeling indicated that each of the variables significantly predicts VAS scores (P < 0.0001). Repeated-measures correlation (rrm2) indicated that [La-] had the closest association with VAS (rrm2 = 0.22, P < 0.0001). CONCLUSION The lower levels of both nausea and changes in [La-], [H+], and pCO2 in response to AR suggest that nausea associated with RS may be causally related with these variables. However, the absence of a close relationship between these variables after the first sprint and the findings that [La-], [H+], and pCO2 only account for 13%-22% of the variation in VAS indicate that other mechanisms may also mediate nausea.
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Affiliation(s)
| | | | | | - Paul A Fournier
- School of Human Sciences (Sport Science, Exercise and Health), University of Western Australia, Crawley, AUSTRALIA
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14
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Yang X, Lu W, Hopper CP, Ke B, Wang B. Nature's marvels endowed in gaseous molecules I: Carbon monoxide and its physiological and therapeutic roles. Acta Pharm Sin B 2021; 11:1434-1445. [PMID: 34221861 PMCID: PMC8245769 DOI: 10.1016/j.apsb.2020.10.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 08/03/2020] [Accepted: 09/07/2020] [Indexed: 02/08/2023] Open
Abstract
Nature has endowed gaseous molecules such as O2, CO2, CO, NO, H2S, and N2 with critical and diverse roles in sustaining life, from supplying energy needed to power life and building blocks for life's physical structure to mediating and coordinating cellular functions. In this article, we give a brief introduction of the complex functions of the various gaseous molecules in life and then focus on carbon monoxide as a specific example of an endogenously produced signaling molecule to highlight the importance of this class of molecules. The past twenty years have seen much progress in understanding CO's mechanism(s) of action and pharmacological effects as well as in developing delivery methods for easy administration. One remarkable trait of CO is its pleiotropic effects that have few parallels, except perhaps its sister gaseous signaling molecules such as nitric oxide and hydrogen sulfide. This review will delve into the sophistication of CO-mediated signaling as well as its validated pharmacological functions and possible therapeutic applications.
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Affiliation(s)
- Xiaoxiao Yang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Wen Lu
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Christopher P. Hopper
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
- Institut für Experimentelle Biomedizin, Universitätsklinikum Würzburg, Würzburg, Bavaria 97080, Germany
| | - Bowen Ke
- Department of Anesthesiology, West China Hospital, Chengdu 610041, China
| | - Binghe Wang
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
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15
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Martínez‐Crespo L, Hewitt SH, De Simone NA, Šindelář V, Davis AP, Butler S, Valkenier H. Transmembrane Transport of Bicarbonate Unravelled*. Chemistry 2021; 27:7367-7375. [PMID: 33932059 PMCID: PMC8251953 DOI: 10.1002/chem.202100491] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Indexed: 02/06/2023]
Abstract
Anion receptors can be used to transport ions across lipid bilayers, which has potential for therapeutic applications. Synthetic bicarbonate transporters are of particular interest, as defects in transmembrane transport of bicarbonate are associated with various diseases. However, no convenient method exists to directly observe bicarbonate transport and study the mechanisms involved. Here, an assay is presented that allows the kinetics of bicarbonate transport into liposomes to be monitored directly and with great sensitivity. The assay utilises an encapsulated europium(III) complex, which exhibits a large increase in emission intensity upon binding bicarbonate. Mechanisms involving CO2 diffusion and the dissipation of a pH gradient are shown to be able to lead to an increase in bicarbonate concentration within liposomes, without transport of the anion occurring at all. By distinguishing these alternative mechanisms from actual bicarbonate transport, this assay will inform the future development of bicarbonate transporters.
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Affiliation(s)
- Luis Martínez‐Crespo
- Université Libre de Bruxelles (ULB)Engineering of Molecular NanoSystems, Ecole polytechnique de BruxellesAvenue F.D. Roosevelt 50, CP165/641050BrusselsBelgium
| | - Sarah H. Hewitt
- Loughborough UniversityDepartment of ChemistryEpinal WayLoughboroughLE11 3TUUK
| | | | - Vladimír Šindelář
- Masaryk UniversityDepartment of Chemistry and RECETOX, Faculty of ScienceKamenice 5625 00BrnoCzech Republic
| | - Anthony P. Davis
- University of BristolSchool of ChemistryCantock's CloseBristolBS8 1TSUK
| | - Stephen Butler
- Loughborough UniversityDepartment of ChemistryEpinal WayLoughboroughLE11 3TUUK
| | - Hennie Valkenier
- Université Libre de Bruxelles (ULB)Engineering of Molecular NanoSystems, Ecole polytechnique de BruxellesAvenue F.D. Roosevelt 50, CP165/641050BrusselsBelgium
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16
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Tsai HH, Schmidt W. The enigma of environmental pH sensing in plants. NATURE PLANTS 2021; 7:106-115. [PMID: 33558755 DOI: 10.1038/s41477-020-00831-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Environmental pH is a critical parameter for innumerable chemical reactions, myriad biological processes and all forms of life. The mechanisms that underlie the perception of external pH (pHe) have been elucidated in detail for bacteria, fungi and mammalian cells; however, little information is available on whether and, if so, how pHe is perceived by plants. This is particularly surprising since hydrogen ion activity of the substrate is of paramount significance for plants, governing the availability of mineral nutrients, the structure of the soil microbiome and the composition of natural plant communities. Rapid changes in soil pH require constant readjustment of nutrient acquisition strategies, which is associated with dynamic alterations in gene expression. Referring to observations made in diverse experimental set-ups that unambiguously show that pHe per se affects gene expression, we hypothesize that sensing of pHe in plants is mandatory to prioritize responses to various simultaneously received environmental cues.
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Affiliation(s)
- Huei-Hsuan Tsai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Wolfgang Schmidt
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan.
- Genome and Systems Biology Degree Program, College of Life Science, National Taiwan University, Taipei, Taiwan.
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17
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Bodman SE, Butler SJ. Advances in anion binding and sensing using luminescent lanthanide complexes. Chem Sci 2021; 12:2716-2734. [PMID: 34164038 PMCID: PMC8179419 DOI: 10.1039/d0sc05419d] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/22/2020] [Indexed: 12/11/2022] Open
Abstract
Luminescent lanthanide complexes have been actively studied as selective anion receptors for the past two decades. Ln(iii) complexes, particularly of europium(iii) and terbium(iii), offer unique photophysical properties that are very valuable for anion sensing in biological media, including long luminescence lifetimes (milliseconds) that enable time-gating methods to eliminate background autofluorescence from biomolecules, and line-like emission spectra that allow ratiometric measurements. By careful design of the organic ligand, stable Ln(iii) complexes can be devised for rapid and reversible anion binding, providing a luminescence response that is fast and sensitive, offering the high spatial resolution required for biological imaging applications. This review focuses on recent progress in the development of Ln(iii) receptors that exhibit sufficiently high anion selectivity to be utilised in biological or environmental sensing applications. We evaluate the mechanisms of anion binding and sensing, and the strategies employed to tune anion affinity and selectivity, through variations in the structure and geometry of the ligand. We highlight examples of luminescent Ln(iii) receptors that have been utilised to detect and quantify specific anions in biological media (e.g. human serum), monitor enzyme reactions in real-time, and visualise target anions with high sensitivity in living cells.
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Affiliation(s)
- Samantha E Bodman
- Department of Chemistry, Loughborough University Epinal Way, Loughborough LE11 3TU UK
| | - Stephen J Butler
- Department of Chemistry, Loughborough University Epinal Way, Loughborough LE11 3TU UK
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18
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Elucidation and genetic intervention of CO2 concentration mechanism in Chlamydomonas reinhardtii for increased plant primary productivity. J Biosci 2020. [DOI: 10.1007/s12038-020-00080-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Kwan GT, Smith TR, Tresguerres M. Immunological characterization of two types of ionocytes in the inner ear epithelium of Pacific Chub Mackerel (Scomber japonicus). J Comp Physiol B 2020; 190:419-431. [PMID: 32468089 DOI: 10.1007/s00360-020-01276-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 12/14/2022]
Abstract
The inner ear is essential for maintaining balance and hearing predator and prey in the environment. Each inner ear contains three CaCO3 otolith polycrystals, which are calcified within an alkaline, K+-rich endolymph secreted by the surrounding epithelium. However, the underlying cellular mechanisms are poorly understood, especially in marine fish. Here, we investigated the presence and cellular localization of several ion-transporting proteins within the saccular epithelium of the Pacific Chub Mackerel (Scomber japonicus). Western blotting revealed the presence of Na+/K+-ATPase (NKA), carbonic anhydrase (CA), Na+-K+-2Cl--co-transporter (NKCC), vacuolar-type H+-ATPase (VHA), plasma membrane Ca2+ ATPase (PMCA), and soluble adenylyl cyclase (sAC). Immunohistochemistry analysis identified two distinct ionocytes types in the saccular epithelium: Type-I ionocytes were mitochondrion-rich and abundantly expressed NKA and NKCC in their basolateral membrane, indicating a role in secreting K+ into the endolymph. On the other hand, Type-II ionocytes were enriched in cytoplasmic CA and VHA, suggesting they help transport HCO3- into the endolymph and remove H+. In addition, both types of ionocytes expressed cytoplasmic PMCA, which is likely involved in Ca2+ transport and homeostasis, as well as sAC, an evolutionary conserved acid-base sensing enzyme that regulates epithelial ion transport. Furthermore, CA, VHA, and sAC were also expressed within the capillaries that supply blood to the meshwork area, suggesting additional mechanisms that contribute to otolith calcification. This information improves our knowledge about the cellular mechanisms responsible for endolymph ion regulation and otolith formation, and can help understand responses to environmental stressors such as ocean acidification.
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Affiliation(s)
- Garfield T Kwan
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, USA
| | - Taylor R Smith
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, USA
| | - Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, USA.
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20
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Tresguerres M, Clifford AM, Harter TS, Roa JN, Thies AB, Yee DP, Brauner CJ. Evolutionary links between intra- and extracellular acid-base regulation in fish and other aquatic animals. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:449-465. [PMID: 32458594 DOI: 10.1002/jez.2367] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/10/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
The acid-base relevant molecules carbon dioxide (CO2 ), protons (H+ ), and bicarbonate (HCO3 - ) are substrates and end products of some of the most essential physiological functions including aerobic and anaerobic respiration, ATP hydrolysis, photosynthesis, and calcification. The structure and function of many enzymes and other macromolecules are highly sensitive to changes in pH, and thus maintaining acid-base homeostasis in the face of metabolic and environmental disturbances is essential for proper cellular function. On the other hand, CO2 , H+ , and HCO3 - have regulatory effects on various proteins and processes, both directly through allosteric modulation and indirectly through signal transduction pathways. Life in aquatic environments presents organisms with distinct acid-base challenges that are not found in terrestrial environments. These include a relatively high CO2 relative to O2 solubility that prevents internal CO2 /HCO3 - accumulation to buffer pH, a lower O2 content that may favor anaerobic metabolism, and variable environmental CO2 , pH and O2 levels that require dynamic adjustments in acid-base homeostatic mechanisms. Additionally, some aquatic animals purposely create acidic or alkaline microenvironments that drive specialized physiological functions. For example, acidifying mechanisms can enhance O2 delivery by red blood cells, lead to ammonia trapping for excretion or buoyancy purposes, or lead to CO2 accumulation to promote photosynthesis by endosymbiotic algae. On the other hand, alkalinizing mechanisms can serve to promote calcium carbonate skeletal formation. This nonexhaustive review summarizes some of the distinct acid-base homeostatic mechanisms that have evolved in aquatic organisms to meet the particular challenges of this environment.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Alexander M Clifford
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Angus B Thies
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Daniel P Yee
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, California
| | - Colin J Brauner
- Department of Zoology, University of British Columbia, Vancouver, Canada
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21
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Measurement of Multi Ion Transport through Human Bronchial Epithelial Cell Line Provides an Insight into the Mechanism of Defective Water Transport in Cystic Fibrosis. MEMBRANES 2020; 10:membranes10030043. [PMID: 32178452 PMCID: PMC7142439 DOI: 10.3390/membranes10030043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/28/2022]
Abstract
We measured concentration changes of sodium, potassium, chloride ions, pH and the transepithelial potential difference by means of ion-selective electrodes, which were placed on both sides of a human bronchial epithelial 16HBE14σ cell line grown on a porous support in the presence of ion channel blockers. We found that, in the isosmotic transepithelial concentration gradient of either sodium or chloride ions, there is an electroneutral transport of the isosmotic solution of sodium chloride in both directions across the cell monolayer. The transepithelial potential difference is below 3 mV. Potassium and pH change plays a minor role in ion transport. Based on our measurements, we hypothesize that in a healthy bronchial epithelium, there is a dynamic balance between water absorption and secretion. Water absorption is caused by the action of two exchangers, Na/H and Cl/HCO3, secreting weakly dissociated carbonic acid in exchange for well dissociated NaCl and water. The water secretion phase is triggered by an apical low volume-dependent factor opening the Cystic Fibrosis Transmembrane Regulator CFTR channel and secreting anions that are accompanied by paracellular sodium and water transport.
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22
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Merrells RJ, Cripps AJ, Chivers PT, Fournier PA. Role of lactic acidosis as a mediator of sprint-mediated nausea. Physiol Rep 2019; 7:e14283. [PMID: 31724342 PMCID: PMC6854110 DOI: 10.14814/phy2.14283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This study aims to determine whether there is a relationship between nausea level and lactic acidosis during recovery from sprinting. In all, 13 recreationally active males completed a 60 s bout of maximal intensity cycling. Prior to and for 45 min following exercise, blood pH, pCO2 , and lactate levels were measured together with nausea. In response to sprinting, nausea, lactate, and H+ concentrations increased and remained elevated for at least 10 min (p < .001), whereas pCO2 increased only transiently (p < .001) before falling below pre-exercise levels (p < .001), with all these variables returning toward pre-exercise levels during recovery. Both measures of nausea adopted for analyses (nausea profile, NP; visual analogue scale, VAS), demonstrated significant repeated measures correlation (rmcorr) post-exercise between nausea and plasma lactate (VAS and NPrrm > 0.595, p < .0001) and H+ concentrations (VAS and NPrrm > 0.689, p < .0001), but an inconsistent relationship with pCO2 (VAS rrm = 0.250, p = .040; NP rrm = 0.144, p = .248) and bicarbonate levels (VAS rrm = -0.252, p = .095; NP rrm = -0.397, p = .008). Linear mixed modeling was used to predict the trajectory of nausea over time, with both lactate and H+ concentrations found to be key predictors of nausea (p < .0001). In conclusion, this study reveals a strong positive relationship between nausea and both H+ and lactate concentrations during recovery from sprinting, a finding consistent with H+ and lactate being potential mediators of nausea post-sprinting. However, as the timing of the recovery of both H+ and lactate was delayed, compared to that of nausea, further research is required to confirm these findings and investigate other potential mechanisms.
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Affiliation(s)
- Robert J. Merrells
- School of Human SciencesDivision Sport Science, Exercise and HealthUniversity of Western AustraliaCrawleyAustralia
- School of Health SciencesThe University of Notre Dame AustraliaFremantleAustralia
| | - Ashley J. Cripps
- School of Health SciencesThe University of Notre Dame AustraliaFremantleAustralia
| | - Paola T. Chivers
- Institute for Health ResearchThe University of Notre Dame AustraliaFremantleAustralia
- Exercise Medicine Research Institute & School of Medical and Health SciencesEdith Cowan UniversityJoondalupAustralia
| | - Paul A. Fournier
- School of Human SciencesDivision Sport Science, Exercise and HealthUniversity of Western AustraliaCrawleyAustralia
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23
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Romero F, Nishigaki T. Comparative genomic analysis suggests that the sperm-specific sodium/proton exchanger and soluble adenylyl cyclase are key regulators of CatSper among the Metazoa. ZOOLOGICAL LETTERS 2019; 5:25. [PMID: 31372239 PMCID: PMC6660944 DOI: 10.1186/s40851-019-0141-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND CatSper is a sperm-specific calcium ion (Ca2+) channel, which regulates sperm flagellar beating by tuning cytoplasmic Ca2+ concentrations. Although this Ca2+ channel is essential for mammalian fertilization, recent bioinformatics analyses have revealed that genes encoding CatSper are heterogeneously distributed throughout the eukaryotes, including vertebrates. As this channel is activated by cytoplasmic alkalization in mammals and sea urchins, it has been proposed that the sperm-specific Na+/H+ exchanger (sNHE, a product of the SLC9C gene family) positively regulates its activity. In mouse, sNHE is functionally coupled to soluble adenylyl cyclase (sAC). CatSper, sNHE, and sAC have thus been considered functionally interconnected in the control of sperm motility, at least in mouse and sea urchin. RESULTS We carried out a comparative genomic analysis to explore phylogenetic relationships among CatSper, sNHE and sAC in eukaryotes. We found that sNHE occurs only in Metazoa, although sAC occurs widely across eukaryotes. In animals, we found correlated and restricted distribution patterns of the three proteins, suggesting coevolution among them in the Metazoa. Namely, nearly all species in which CatSper is conserved also preserve sNHE and sAC. In contrast, in species without sAC, neither CatSper nor sNHE is conserved. On the other hand, the distribution of another testis-specific NHE (NHA, a product of the SLC9B gene family) does not show any apparent association with that of CatSper. CONCLUSIONS Our results suggest that CatSper, sNHE and sAC form prototypical machinery that functions in regulating sperm flagellar beating in Metazoa. In non-metazoan species, CatSper may be regulated by other H+ transporters, or its activity might be independent of cytoplasmic pH.
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Affiliation(s)
- Francisco Romero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología. Universidad Nacional Autónoma de México (IBT-UNAM). Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos Mexico
| | - Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología. Universidad Nacional Autónoma de México (IBT-UNAM). Av. Universidad 2001, Col. Chamilpa, 62210 Cuernavaca, Morelos Mexico
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24
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AMP-activated Protein Kinase Controls Immediate Early Genes Expression Following Synaptic Activation Through the PKA/CREB Pathway. Int J Mol Sci 2018; 19:ijms19123716. [PMID: 30467274 PMCID: PMC6321501 DOI: 10.3390/ijms19123716] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/14/2018] [Accepted: 11/20/2018] [Indexed: 11/17/2022] Open
Abstract
Long-term memory formation depends on the expression of immediate early genes (IEGs). Their expression, which is induced by synaptic activation, is mainly regulated by the 3',5'-cyclic AMP (cAMP)-dependent protein kinase/cAMP response element binding protein (cAMP-dependent protein kinase (PKA)/ cAMP response element binding (CREB)) signaling pathway. Synaptic activation being highly energy demanding, neurons must maintain their energetic homeostasis in order to successfully induce long-term memory formation. In this context, we previously demonstrated that the expression of IEGs required the activation of AMP-activated protein kinase (AMPK) to sustain the energetic requirements linked to synaptic transmission. Here, we sought to determine the molecular mechanisms by which AMPK regulates the expression of IEGs. To this end, we assessed the involvement of AMPK in the regulation of pathways involved in the expression of IEGs upon synaptic activation in differentiated primary neurons. Our data demonstrated that AMPK regulated IEGs transcription via the PKA/CREB pathway, which relied on the activity of the soluble adenylyl cyclase. Our data highlight the interplay between AMPK and PKA/CREB signaling pathways that allows synaptic activation to be transduced into the expression of IEGs, thus exemplifying how learning and memory mechanisms are under metabolic control.
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25
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Xavier JC, Preiner M, Martin WF. Something special about CO-dependent CO 2 fixation. FEBS J 2018; 285:4181-4195. [PMID: 30240136 PMCID: PMC6282760 DOI: 10.1111/febs.14664] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 08/08/2018] [Accepted: 09/19/2018] [Indexed: 01/02/2023]
Abstract
Carbon dioxide enters metabolism via six known CO2 fixation pathways, of which only one is linear, exergonic in the direction of CO2‐assimilation, and present in both bacterial and archaeal anaerobes – the Wood‐Ljungdahl (WL) or reductive acetyl‐CoA pathway. Carbon monoxide (CO) plays a central role in the WL pathway as an energy rich intermediate. Here, we scan the major biochemical reaction databases for reactions involving CO and CO2. We identified 415 reactions corresponding to enzyme commission (EC) numbers involving CO2, which are non‐randomly distributed across different biochemical pathways. Their taxonomic distribution, reversibility under physiological conditions, cofactors and prosthetic groups are summarized. In contrast to CO2, only 15 reaction classes involving CO were detected. Closer inspection reveals that CO interfaces with metabolism and the carbon cycle at only two enzymes: anaerobic carbon monoxide dehydrogenase (CODH), a Ni‐ and Fe‐containing enzyme that generates CO for CO2 fixation in the WL pathway, and aerobic CODH, a Mo‐ and Cu‐containing enzyme that oxidizes environmental CO as an electron source. The CO‐dependent reaction of the WL pathway involves carbonyl insertion into a methyl carbon‐nickel at the Ni‐Fe‐S A‐cluster of acetyl‐CoA synthase (ACS). It appears that no alternative mechanisms to the CO‐dependent reaction of ACS have evolved in nearly 4 billion years, indicating an ancient and mechanistically essential role for CO at the onset of metabolism.
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Affiliation(s)
- Joana C Xavier
- Institut für Molekulare Evolution, Heinrich Heine Universität Düsseldorf, Germany
| | - Martina Preiner
- Institut für Molekulare Evolution, Heinrich Heine Universität Düsseldorf, Germany
| | - William F Martin
- Institut für Molekulare Evolution, Heinrich Heine Universität Düsseldorf, Germany.,Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
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26
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Gonçalves CM, Mulkey DK. Bicarbonate directly modulates activity of chemosensitive neurons in the retrotrapezoid nucleus. J Physiol 2018; 596:4033-4042. [PMID: 29873079 DOI: 10.1113/jp276104] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/14/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Changes in CO2 result in corresponding changes in both H+ and HCO3- and despite evidence that HCO3- can function as an independent signalling molecule, there is little evidence suggesting HCO3- contributes to respiratory chemoreception. We show that HCO3- directly activates chemosensitive retrotrapezoid nucleus (RTN) neurons. Identifying all relevant signalling molecules is essential for understanding how chemoreceptors function, and because HCO3- and H+ are buffered by separate cellular mechanisms, having the ability to sense both modalities adds additional information regarding changes in CO2 that are not necessarily reflected by pH alone. HCO3- may be particularly important for regulating activity of RTN chemoreceptors during sustained intracellular acidifications when TASK-2 channels, which appear to be the sole intracellular pH sensor, are minimally active. ABSTRACT Central chemoreception is the mechanism by which the brain regulates breathing in response to changes in tissue CO2 /H+ . The retrotrapezoid nucleus (RTN) is an important site of respiratory chemoreception. Mechanisms underlying RTN chemoreception involve H+ -mediated activation of chemosensitive neurons and CO2 /H+ -evoked ATP-purinergic signalling by local astrocytes, which activates chemosensitive neurons directly and indirectly by maintaining vascular tone when CO2 /H+ levels are high. Although changes in CO2 result in corresponding changes in both H+ and HCO3- and despite evidence that HCO3- can function as an independent signalling molecule, there is little evidence suggesting HCO3- contributes to respiratory chemoreception. Therefore, the goal of this study was to determine whether HCO3- regulates activity of chemosensitive RTN neurons independent of pH. Cell-attached recordings were used to monitor activity of chemosensitive RTN neurons in brainstem slices (300 μm thick) isolated from rat pups (postnatal days 7-11) during exposure to low or high concentrations of HCO3- . In a subset of experiments, we also included 2',7'-bis(2carboxyethyl)-5-(and 6)-carboxyfluorescein (BCECF) in the internal solution to measure pHi under each experimental condition. We found that HCO3- activates chemosensitive RTN neurons by mechanisms independent of intracellular or extracellular pH, glutamate, GABA, glycine or purinergic signalling, soluble adenylyl cyclase activity, nitric oxide or KCNQ channels. These results establish HCO3- as a novel independent modulator of chemoreceptor activity, and because the levels of HCO3- along with H+ are buffered by independent cellular mechanisms, these results suggest HCO3- chemoreception adds additional information regarding changes in CO2 that are not necessarily reflected by pH.
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Affiliation(s)
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs CT, USA
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27
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Barott KL, Barron ME, Tresguerres M. Identification of a molecular pH sensor in coral. Proc Biol Sci 2018; 284:rspb.2017.1769. [PMID: 29093223 DOI: 10.1098/rspb.2017.1769] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 10/04/2017] [Indexed: 12/26/2022] Open
Abstract
Maintaining stable intracellular pH (pHi) is essential for homeostasis, and requires the ability to both sense pH changes that may result from internal and external sources, and to regulate downstream compensatory pH pathways. Here we identified the cAMP-producing enzyme soluble adenylyl cyclase (sAC) as the first molecular pH sensor in corals. sAC protein was detected throughout coral tissues, including those involved in symbiosis and calcification. Application of a sAC-specific inhibitor caused significant and reversible pHi acidosis in isolated coral cells under both dark and light conditions, indicating sAC is essential for sensing and regulating pHi perturbations caused by respiration and photosynthesis. Furthermore, pHi regulation during external acidification was also dependent on sAC activity. Thus, sAC is a sensor and regulator of pH disturbances from both metabolic and external origin in corals. Since sAC is present in all coral cell types, and the cAMP pathway can regulate virtually every aspect of cell physiology through post-translational modifications of proteins, sAC is likely to trigger multiple homeostatic mechanisms in response to pH disturbances. This is also the first evidence that sAC modulates pHi in any non-mammalian animal. Since corals are basal metazoans, our results indicate this function is evolutionarily conserved across animals.
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Affiliation(s)
- Katie L Barott
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.,Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Megan E Barron
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Martin Tresguerres
- Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Wiggins SV, Steegborn C, Levin LR, Buck J. Pharmacological modulation of the CO 2/HCO 3-/pH-, calcium-, and ATP-sensing soluble adenylyl cyclase. Pharmacol Ther 2018; 190:173-186. [PMID: 29807057 DOI: 10.1016/j.pharmthera.2018.05.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cyclic AMP (cAMP), the prototypical second messenger, has been implicated in a wide variety of (often opposing) physiological processes. It simultaneously mediates multiple, diverse processes, often within a single cell, by acting locally within independently-regulated and spatially-restricted microdomains. Within each microdomain, the level of cAMP will be dependent upon the balance between its synthesis by adenylyl cyclases and its degradation by phosphodiesterases (PDEs). In mammalian cells, there are many PDE isoforms and two types of adenylyl cyclases; the G protein regulated transmembrane adenylyl cyclases (tmACs) and the CO2/HCO3-/pH-, calcium-, and ATP-sensing soluble adenylyl cyclase (sAC). Discriminating the roles of individual cyclic nucleotide microdomains requires pharmacological modulators selective for the various PDEs and/or adenylyl cyclases. Such tools present an opportunity to develop therapeutics specifically targeted to individual cAMP dependent pathways. The pharmacological modulators of tmACs have recently been reviewed, and in this review, we describe the current status of pharmacological tools available for studying sAC.
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Affiliation(s)
- Shakarr V Wiggins
- Graduate Program in Neuroscience, Weill Cornell Medicine, New York, NY 10065, United States
| | - Clemens Steegborn
- Department of Biochemistry, University of Bayreuth, 95440 Bayreuth, Germany
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, United States.
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, United States
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Schirmer I, Bualeong T, Budde H, Cimiotti D, Appukuttan A, Klein N, Steinwascher P, Reusch P, Mügge A, Meyer R, Ladilov Y, Jaquet K. Soluble adenylyl cyclase: A novel player in cardiac hypertrophy induced by isoprenaline or pressure overload. PLoS One 2018; 13:e0192322. [PMID: 29466442 PMCID: PMC5821345 DOI: 10.1371/journal.pone.0192322] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 01/22/2018] [Indexed: 12/29/2022] Open
Abstract
Aims In contrast to the membrane bound adenylyl cyclases, the soluble adenylyl cyclase (sAC) is activated by bicarbonate and divalent ions including calcium. sAC is located in the cytosol, nuclei and mitochondria of several tissues including cardiac muscle. However, its role in cardiac pathology is poorly understood. Here we investigate whether sAC is involved in hypertrophic growth using two different model systems. Methods and results In isolated adult rat cardiomyocytes hypertrophy was induced by 24 h β1-adrenoceptor stimulation using isoprenaline (ISO) and a β2-adrenoceptor antagonist (ICI118,551). To monitor hypertrophy cell size along with RNA/DNA- and protein/DNA ratios as well as the expression level of α-skeletal actin were analyzed. sAC activity was suppressed either by treatment with its specific inhibitor KH7 or by knockdown. Both pharmacological inhibition and knockdown blunted hypertrophic growth and reduced expression levels of α-skeletal actin in ISO/ICI treated rat cardiomyocytes. To analyze the underlying cellular mechanism expression levels of phosphorylated CREB, B-Raf and Erk1/2 were examined by western blot. The results suggest the involvement of B-Raf, but not of Erk or CREB in the pro-hypertrophic action of sAC. In wild type and sAC knockout mice pressure overload was induced by transverse aortic constriction. Hemodynamics, heart weight and the expression level of the atrial natriuretic peptide were analyzed. In accordance, transverse aortic constriction failed to induce hypertrophy in sAC knockout mice. Mechanistic analysis revealed a potential role of Erk1/2 in TAC-induced hypertrophy. Conclusion Soluble adenylyl cyclase might be a new pivotal player in the cardiac hypertrophic response either to long-term β1-adrenoceptor stimulation or to pressure overload.
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Affiliation(s)
- Ilona Schirmer
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Tippaporn Bualeong
- Institute of Physiology II, Hospital of the Friedrich-Wilhelms-University of Bonn, Bonn, Germany
| | - Heidi Budde
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Diana Cimiotti
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Avinash Appukuttan
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Nicole Klein
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Philip Steinwascher
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Peter Reusch
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Andreas Mügge
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
| | - Rainer Meyer
- Institute of Physiology II, Hospital of the Friedrich-Wilhelms-University of Bonn, Bonn, Germany
| | - Yury Ladilov
- Clinical Pharmacology, Faculty of Medicine, Ruhr-University of Bochum, Bochum, Germany
| | - Kornelia Jaquet
- Cardiology, Research Laboratory Molecular Cardiology, BG Bergmannsheil and St. Josef-Hospital, clinics of the Ruhr-University Bochum, Bochum, Germany
- * E-mail:
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30
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Quintero MC, Putnam RW, Cordovez JM. Theoretical perspectives on central chemosensitivity: CO2/H+-sensitive neurons in the locus coeruleus. PLoS Comput Biol 2017; 13:e1005853. [PMID: 29267284 PMCID: PMC5755939 DOI: 10.1371/journal.pcbi.1005853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 01/05/2018] [Accepted: 10/26/2017] [Indexed: 12/18/2022] Open
Abstract
Central chemoreceptors are highly sensitive neurons that respond to changes in pH and CO2 levels. An increase in CO2/H+ typically reflects a rise in the firing rate of these neurons, which stimulates an increase in ventilation. Here, we present an ionic current model that reproduces the basic electrophysiological activity of individual CO2/H+-sensitive neurons from the locus coeruleus (LC). We used this model to explore chemoreceptor discharge patterns in response to electrical and chemical stimuli. The modeled neurons showed both stimulus-evoked activity and spontaneous activity under physiological parameters. Neuronal responses to electrical and chemical stimulation showed specific firing patterns of spike frequency adaptation, postinhibitory rebound, and post-stimulation recovery. Conversely, the response to chemical stimulation alone (based on physiological CO2/H+ changes), in the absence of external depolarizing stimulation, showed no signs of postinhibitory rebound or post-stimulation recovery, and no depolarizing sag. A sensitivity analysis for the firing-rate response to the different stimuli revealed that the contribution of an applied stimulus current exceeded that of the chemical signals. The firing-rate response increased indefinitely with injected depolarizing current, but reached saturation with chemical stimuli. Our computational model reproduced the regular pacemaker-like spiking pattern, action potential shape, and most of the membrane properties that characterize CO2/H+-sensitive neurons from the locus coeruleus. This validates the model and highlights its potential as a tool for studying the cellular mechanisms underlying the altered central chemosensitivity present in a variety of disorders such as sudden infant death syndrome, depression, and anxiety. In addition, the model results suggest that small external electrical signals play a greater role in determining the chemosensitive response to changes in CO2/H+ than previously thought. This highlights the importance of considering electrical synaptic transmission in studies of intrinsic chemosensitivity. The sensory mechanism by which changes in CO2 and H+ levels are detected in the brain is known as central chemoreception. Altered chemoreception is common to a wide variety of clinical conditions, including sleep apnea, sudden infant death syndrome, hyperventilation, depression, anxiety and asthma. In addition, CO2/H+-sensitive neurons are present in some regions of the brain that have been identified as drug targets for the treatment of anxiety and panic disorders. We are interested in understanding the cellular mechanisms that determine and modulate the behavior of these neurons. We previously investigated possible mechanisms underlying their behavior in rats to elucidate whether they respond to changes in intracellular or extracellular pH, CO2, or a combination of these stimuli. To study the roles that signals and ion channel targets play in individual neurons we develop mathematical models that simulate their electrochemical behavior and their responses to hypercapnic and/or acidotic stimuli. Nowadays, we are focused on using computational tools to explore the firing pattern of such neurons in response to chemical (CO2/H+) and electrical (synaptic) stimulation. Our results reveal significant effects of electrical stimulation on the responses of brainstem neurons and highlight the importance of considering synaptic transmission in experimental studies of chemosensitivity.
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Affiliation(s)
- Maria C. Quintero
- Biomedical Engineering Department, Universidad de Los Andes, Bogotá, Colombia
- * E-mail: (MQ); (JC)
| | - Robert W. Putnam
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, United States of America
| | - Juan M. Cordovez
- Biomedical Engineering Department, Universidad de Los Andes, Bogotá, Colombia
- * E-mail: (MQ); (JC)
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31
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Rahman N, Ramos-Espiritu L, Milner TA, Buck J, Levin LR. Soluble adenylyl cyclase is essential for proper lysosomal acidification. J Gen Physiol 2017; 148:325-39. [PMID: 27670898 PMCID: PMC5037342 DOI: 10.1085/jgp.201611606] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 09/08/2016] [Indexed: 01/07/2023] Open
Abstract
Lysosomes, the degradative organelles of the endocytic and autophagic pathways, function at an acidic pH. Lysosomes are acidified by the proton-pumping vacuolar ATPase (V-ATPase), but the molecular processes that set the organelle's pH are not completely understood. In particular, pH-sensitive signaling enzymes that can regulate lysosomal acidification in steady-state physiological conditions have yet to be identified. Soluble adenylyl cyclase (sAC) is a widely expressed source of cAMP that serves as a physiological pH sensor in cells. For example, in proton-secreting epithelial cells, sAC is responsible for pH-dependent translocation of V-ATPase to the luminal surface. Here we show genetically and pharmacologically that sAC is also essential for lysosomal acidification. In the absence of sAC, V-ATPase does not properly localize to lysosomes, lysosomes fail to fully acidify, lysosomal degradative capacity is diminished, and autophagolysosomes accumulate.
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Affiliation(s)
- Nawreen Rahman
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065 Graduate Program in Neuroscience, Weill Cornell Medical College, New York, NY 10065
| | | | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065 Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
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32
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Mackinder LCM, Chen C, Leib RD, Patena W, Blum SR, Rodman M, Ramundo S, Adams CM, Jonikas MC. A Spatial Interactome Reveals the Protein Organization of the Algal CO 2-Concentrating Mechanism. Cell 2017; 171:133-147.e14. [PMID: 28938113 PMCID: PMC5616186 DOI: 10.1016/j.cell.2017.08.044] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/30/2017] [Accepted: 08/22/2017] [Indexed: 11/20/2022]
Abstract
Approximately one-third of global CO2 fixation is performed by eukaryotic algae. Nearly all algae enhance their carbon assimilation by operating a CO2-concentrating mechanism (CCM) built around an organelle called the pyrenoid, whose protein composition is largely unknown. Here, we developed tools in the model alga Chlamydomonas reinhardtii to determine the localizations of 135 candidate CCM proteins and physical interactors of 38 of these proteins. Our data reveal the identity of 89 pyrenoid proteins, including Rubisco-interacting proteins, photosystem I assembly factor candidates, and inorganic carbon flux components. We identify three previously undescribed protein layers of the pyrenoid: a plate-like layer, a mesh layer, and a punctate layer. We find that the carbonic anhydrase CAH6 is in the flagella, not in the stroma that surrounds the pyrenoid as in current models. These results provide an overview of proteins operating in the eukaryotic algal CCM, a key process that drives global carbon fixation.
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Affiliation(s)
- Luke C M Mackinder
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Chris Chen
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ryan D Leib
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA 94305, USA
| | - Weronika Patena
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sean R Blum
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Matthew Rodman
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Silvia Ramundo
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
| | - Christopher M Adams
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA 94305, USA
| | - Martin C Jonikas
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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33
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Baby S, Johnson AJ, Zachariah EJ, Hussain AA. Nepenthes pitchers are CO 2-enriched cavities, emit CO 2 to attract preys. Sci Rep 2017; 7:11281. [PMID: 28900277 PMCID: PMC5595901 DOI: 10.1038/s41598-017-11414-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 08/23/2017] [Indexed: 11/09/2022] Open
Abstract
Carnivorous plants of the genus Nepenthes supplement their nutrient deficiency by capturing arthropods or by mutualistic interactions, through their leaf-evolved biological traps (pitchers). Though there are numerous studies on these traps, mostly on their prey capture mechanisms, the gas composition inside them remains unknown. Here we show that, Nepenthes unopened pitchers are CO2-enriched 'cavities', when open they emit CO2, and the CO2 gradient around open pitchers acts as a cue attracting preys towards them. CO2 contents in near mature, unopened Nepenthes pitchers were in the range 2500-5000 ppm. Gas collected from inside open N. khasiana pitchers showed CO2 at 476.75 ± 59.83 ppm. CO2-enriched air-streaming through N. khasiana pitchers (at 619.83 ± 4.53 ppm) attracted (captured) substantially higher number of aerial preys compared to air-streamed pitchers (CO2 at 412.76 ± 4.51 ppm). High levels of CO2 dissolved in acidic Nepenthes pitcher fluids were also detected. We demonstrate respiration as the source of elevated CO2 within Nepenthes pitchers. Most unique features of Nepenthes pitchers, viz., high growth rate, enhanced carbohydrate levels, declined protein levels, low photosynthetic capacity, high respiration rate and evolved stomata, are influenced by the CO2-enriched environment within them.
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Affiliation(s)
- Sabulal Baby
- Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Pacha-Palode, Thiruvananthapuram, 695 562, Kerala, India.
| | - Anil John Johnson
- Phytochemistry and Phytopharmacology Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Pacha-Palode, Thiruvananthapuram, 695 562, Kerala, India
| | - Elavinamannil Jacob Zachariah
- Atmospheric Sciences Division, National Centre for Earth Science Studies, Post Box No. 7250, Akkulam, Thiruvananthapuram, 695 011, Kerala, India
| | - Abdul Azeez Hussain
- Garden Management Division, Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Pacha-Palode, Thiruvananthapuram, 695 562, Kerala, India
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Roa JN, Tresguerres M. Bicarbonate-sensing soluble adenylyl cyclase is present in the cell cytoplasm and nucleus of multiple shark tissues. Physiol Rep 2017; 5:5/2/e13090. [PMID: 28108644 PMCID: PMC5269408 DOI: 10.14814/phy2.13090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 11/30/2016] [Indexed: 12/31/2022] Open
Abstract
The enzyme soluble adenylyl cyclase (sAC) is directly stimulated by bicarbonate (HCO3−) to produce the signaling molecule cyclic adenosine monophosphate (cAMP). Because sAC and sAC‐related enzymes are found throughout phyla from cyanobacteria to mammals and they regulate cell physiology in response to internal and external changes in pH, CO2, and HCO3−, sAC is deemed an evolutionarily conserved acid‐base sensor. Previously, sAC has been reported in dogfish shark and round ray gill cells, where they sense and counteract blood alkalosis by regulating the activity of V‐type H+‐ ATPase. Here, we report the presence of sAC protein in gill, rectal gland, cornea, intestine, white muscle, and heart of leopard shark Triakis semifasciata. Co‐expression of sAC with transmembrane adenylyl cyclases supports the presence of cAMP signaling microdomains. Furthermore, immunohistochemistry on tissue sections, and western blots and cAMP‐activity assays on nucleus‐enriched fractions demonstrate the presence of sAC protein in and around nuclei. These results suggest that sAC modulates multiple physiological processes in shark cells, including nuclear functions.
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Affiliation(s)
- Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography University of California San Diego, 9500 Gilman Drive La Jolla, California, 92093, USA
| | - Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography University of California San Diego, 9500 Gilman Drive La Jolla, California, 92093, USA
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35
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Expression of Carbonic Anhydrase I in Motor Neurons and Alterations in ALS. Int J Mol Sci 2016; 17:ijms17111820. [PMID: 27809276 PMCID: PMC5133821 DOI: 10.3390/ijms17111820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 12/27/2022] Open
Abstract
Carbonic anhydrase I (CA1) is the cytosolic isoform of mammalian α-CA family members which are responsible for maintaining pH homeostasis in the physiology and pathology of organisms. A subset of CA isoforms are known to be expressed and function in the central nervous system (CNS). CA1 has not been extensively characterized in the CNS. In this study, we demonstrate that CA1 is expressed in the motor neurons in human spinal cord. Unexpectedly, a subpopulation of CA1 appears to be associated with endoplasmic reticulum (ER) membranes. In addition, the membrane-associated CA1s are preferentially upregulated in amyotrophic lateral sclerosis (ALS) and exhibit altered distribution in motor neurons. Furthermore, long-term expression of CA1 in mammalian cells activates apoptosis. Our results suggest a previously unknown role for CA1 function in the CNS and its potential involvement in motor neuron degeneration in ALS.
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36
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Ramos-Espiritu L, Kleinboelting S, Navarrete FA, Alvau A, Visconti PE, Valsecchi F, Starkov A, Manfredi G, Buck H, Adura C, Zippin JH, van den Heuvel J, Glickman JF, Steegborn C, Levin LR, Buck J. Discovery of LRE1 as a specific and allosteric inhibitor of soluble adenylyl cyclase. Nat Chem Biol 2016; 12:838-44. [PMID: 27547922 PMCID: PMC5030147 DOI: 10.1038/nchembio.2151] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 05/23/2016] [Indexed: 12/22/2022]
Abstract
The prototypical second messenger cAMP regulates a wide variety of physiological processes. It can simultaneously mediate diverse functions by acting locally in independently regulated microdomains. In mammalian cells, two types of adenylyl cyclase generate cAMP: G-protein-regulated transmembrane adenylyl cyclases and bicarbonate-, calcium- and ATP-regulated soluble adenylyl cyclase (sAC). Because each type of cyclase regulates distinct microdomains, methods to distinguish between them are needed to understand cAMP signaling. We developed a mass-spectrometry-based adenylyl cyclase assay, which we used to identify a new sAC-specific inhibitor, LRE1. LRE1 bound to the bicarbonate activator binding site and inhibited sAC via a unique allosteric mechanism. LRE1 prevented sAC-dependent processes in cellular and physiological systems, and it will facilitate exploration of the therapeutic potential of sAC inhibition.
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Affiliation(s)
- Lavoisier Ramos-Espiritu
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | | | - Felipe A Navarrete
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Antonio Alvau
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Pablo E Visconti
- Department of Veterinary and Animal Science, University of Massachusetts, Amherst, Massachusetts, USA
| | - Federica Valsecchi
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Anatoly Starkov
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Giovanni Manfredi
- Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York, USA
| | - Hannes Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
| | - Carolina Adura
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | - Jonathan H Zippin
- Department of Dermatology, Weill Cornell Medical College, New York, New York, USA
| | | | - J Fraser Glickman
- The High-Throughput Screening and Spectroscopy Resource Center, The Rockefeller University, New York, New York, USA
| | - Clemens Steegborn
- Department of Biochemistry, University of Bayreuth, Bayreuth, Germany
| | - Lonny R Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, New York, USA
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Pauluhn J. Risk assessment in combustion toxicology: Should carbon dioxide be recognized as a modifier of toxicity or separate toxicological entity? Toxicol Lett 2016; 262:142-152. [PMID: 27664840 DOI: 10.1016/j.toxlet.2016.09.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/20/2016] [Accepted: 09/20/2016] [Indexed: 10/21/2022]
Abstract
To characterize the accumulated hazards associated with the inhalation of gases typical of combustion products, a time-integrated value known as the fractional effective dose (FED) is used. This FED is maintained by the International Organization for Standardization (ISO) and made publicly available as the Standard ISO 13571. The current FED calculation related to asphyxiant gases is based on non-human primate data to estimate the 50% probability of humans to be incapacitated or not being able to execute any escape paradigm from fires. The objective of this paper was to compare two to calculate FEDs of the most common mixture of asphyxiant fire gases CO, HCN, and CO2. The first was based on the current ISO 13571 (draft) standard, the alternative second method applied the conceptual principles established for the derivation of Acute Emergency Response Planning Guideline values. The alternative approach applied one third of the non-lethal threshold concentration (LC01) as the most suitable and robust Point of Departure (POD) to estimate the threshold characterizing 'impairment of escape' in the absence of post-exposure mortality. The hyperventilation correction factor for CO2 of ISO 13571 was replaced by a separate term that accounts for the inherent acute toxicity of CO2. This analysis supports the conclusion that the current ISO 13571 standard misjudges the impact of the acute toxicity elicited by concentrations of CO2 exceeding ≈6%. While underestimating the hazards attributable to CO2, the hyperventilation adjustment factor suggested by this standard is biased to markedly overestimate the hazards assigned to CO and HCN in fire effluents.
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Affiliation(s)
- Juergen Pauluhn
- Hannover Medical School, Hannover, Germany; 4th Military Medical University, Xi'an, China.
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38
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Böhme I, Bosserhoff AK. Acidic tumor microenvironment in human melanoma. Pigment Cell Melanoma Res 2016; 29:508-23. [PMID: 27233233 DOI: 10.1111/pcmr.12495] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/25/2016] [Indexed: 12/18/2022]
Abstract
One characteristic of solid tumors such as malignant melanoma is the acidification of the tumor microenvironment. The deregulation of cancer cell metabolism is considered a main cause of extracellular acidosis. Here, cancer cells utilize aerobic glycolysis instead of oxidative phosphorylation even under normoxic conditions, as originally described by Otto Warburg. These metabolic alterations cause enhanced acid production, especially of lactate and carbon dioxide (CO2 ). The extensive production of acidic metabolites and the enhanced acid export to the extracellular space cause a consistent acidification of the tumor microenvironment, thus promoting the formation of an acid-resistant tumor cell population with increased invasive and metastatic potential. As melanoma is one of the deadliest and most metastatic forms of cancer, understanding the effects of this extracellular acidosis on human melanoma cells with distinct metastatic properties is important. The aim of this review was to summarize recent studies of the acidification of the tumor microenvironment, focusing on the specific effects of the acidic milieu on melanoma cells and to give a short overview of therapeutic approaches.
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Affiliation(s)
- Ines Böhme
- Institute of Biochemistry, Emil-Fischer-Centrum, Friedrich Alexander University Erlangen-Nürnberg, Erlangen-Nürnberg, Germany
| | - Anja Katrin Bosserhoff
- Institute of Biochemistry, Emil-Fischer-Centrum, Friedrich Alexander University Erlangen-Nürnberg, Erlangen-Nürnberg, Germany. .,Comprehensive Cancer Center Erlangen-EMN, University of Erlangen, Erlangen, Germany.
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39
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Roa JN, Tresguerres M. Soluble adenylyl cyclase is an acid-base sensor in epithelial base-secreting cells. Am J Physiol Cell Physiol 2016; 311:C340-9. [PMID: 27335168 DOI: 10.1152/ajpcell.00089.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/16/2016] [Indexed: 12/20/2022]
Abstract
Blood acid-base regulation by specialized epithelia, such as gills and kidney, requires the ability to sense blood acid-base status. Here, we developed primary cultures of ray (Urolophus halleri) gill cells to study mechanisms for acid-base sensing without the interference of whole animal hormonal regulation. Ray gills have abundant base-secreting cells, identified by their noticeable expression of vacuolar-type H(+)-ATPase (VHA), and also express the evolutionarily conserved acid-base sensor soluble adenylyl cyclase (sAC). Exposure of cultured cells to extracellular alkalosis (pH 8.0, 40 mM HCO3 (-)) triggered VHA translocation to the cell membrane, similar to previous reports in live animals experiencing blood alkalosis. VHA translocation was dependent on sAC, as it was blocked by the sAC-specific inhibitor KH7. Ray gill base-secreting cells also express transmembrane adenylyl cyclases (tmACs); however, tmAC inhibition by 2',5'-dideoxyadenosine did not prevent alkalosis-dependent VHA translocation, and tmAC activation by forskolin reduced the abundance of VHA at the cell membrane. This study demonstrates that sAC is a necessary and sufficient sensor of extracellular alkalosis in ray gill base-secreting cells. In addition, this study indicates that different sources of cAMP differentially modulate cell biology.
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Affiliation(s)
- Jinae N Roa
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California
| | - Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California
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Whittamore JM, Hatch M. Chronic metabolic acidosis reduces urinary oxalate excretion and promotes intestinal oxalate secretion in the rat. Urolithiasis 2015; 43:489-99. [DOI: 10.1007/s00240-015-0801-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/30/2015] [Indexed: 11/30/2022]
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Aristizábal-Salazar RE, Calvo-Torres LF, Valencia-Arango LA, Montoya-Cañon M, Barbosa-Gantiva O, Hincapié-Baena V. Equilibrio ácido-base: el mejor enfoque clínico. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1016/j.rca.2015.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Aristizábal-Salazar RE, Calvo-Torres LF, Valencia-Arango LA, Montoya-Cañon M, Barbosa-Gantiva O, Hincapié-Baena V. Acid–base equilibrium: The best clinical approach. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1016/j.rcae.2015.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Abstract
ABSTRACT
The change in oceanic carbonate chemistry due to increased atmospheric PCO2 has caused pH to decline in marine surface waters, a phenomenon known as ocean acidification (OA). The effects of OA on organisms have been shown to be widespread among diverse taxa from a wide range of habitats. The majority of studies of organismal response to OA are in short-term exposures to future levels of PCO2. From such studies, much information has been gathered on plastic responses organisms may make in the future that are beneficial or harmful to fitness. Relatively few studies have examined whether organisms can adapt to negative-fitness consequences of plastic responses to OA. We outline major approaches that have been used to study the adaptive potential for organisms to OA, which include comparative studies and experimental evolution. Organisms that inhabit a range of pH environments (e.g. pH gradients at volcanic CO2 seeps or in upwelling zones) have great potential for studies that identify adaptive shifts that have occurred through evolution. Comparative studies have advanced our understanding of adaptation to OA by linking whole-organism responses with cellular mechanisms. Such optimization of function provides a link between genetic variation and adaptive evolution in tuning optimal function of rate-limiting cellular processes in different pH conditions. For example, in experimental evolution studies of organisms with short generation times (e.g. phytoplankton), hundreds of generations of growth under future conditions has resulted in fixed differences in gene expression related to acid–base regulation. However, biochemical mechanisms for adaptive responses to OA have yet to be fully characterized, and are likely to be more complex than simply changes in gene expression or protein modification. Finally, we present a hypothesis regarding an unexplored area for biochemical adaptation to ocean acidification. In this hypothesis, proteins and membranes exposed to the external environment, such as epithelial tissues, may be susceptible to changes in external pH. Such biochemical systems could be adapted to a reduced pH environment by adjustment of weak bonds in an analogous fashion to biochemical adaptation to temperature. Whether such biochemical adaptation to OA exists remains to be discovered.
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Affiliation(s)
- Jonathon H. Stillman
- Romberg Tiburon Center, Department of Biology, San Francisco State University, Tiburon, CA 94920, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94709, USA
| | - Adam W. Paganini
- Romberg Tiburon Center, Department of Biology, San Francisco State University, Tiburon, CA 94920, USA
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The Carbonic Anhydrase Inhibitor Ethoxzolamide Inhibits the Mycobacterium tuberculosis PhoPR Regulon and Esx-1 Secretion and Attenuates Virulence. Antimicrob Agents Chemother 2015; 59:4436-45. [PMID: 25987613 DOI: 10.1128/aac.00719-15] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/07/2015] [Indexed: 02/03/2023] Open
Abstract
Mycobacterium tuberculosis must sense and adapt to host environmental cues to establish and maintain an infection. The two-component regulatory system PhoPR plays a central role in sensing and responding to acidic pH within the macrophage and is required for M. tuberculosis intracellular replication and growth in vivo. Therefore, the isolation of compounds that inhibit PhoPR-dependent adaptation may identify new antivirulence therapies to treat tuberculosis. Here, we report that the carbonic anhydrase inhibitor ethoxzolamide inhibits the PhoPR regulon and reduces pathogen virulence. We show that treatment of M. tuberculosis with ethoxzolamide recapitulates phoPR mutant phenotypes, including downregulation of the core PhoPR regulon, altered accumulation of virulence-associated lipids, and inhibition of Esx-1 protein secretion. Quantitative single-cell imaging of a PhoPR-dependent fluorescent reporter strain demonstrates that ethoxzolamide inhibits PhoPR-regulated genes in infected macrophages and mouse lungs. Moreover, ethoxzolamide reduces M. tuberculosis growth in both macrophages and infected mice. Ethoxzolamide inhibits M. tuberculosis carbonic anhydrase activity, supporting a previously unrecognized link between carbonic anhydrase activity and PhoPR signaling. We propose that ethoxzolamide may be pursued as a new class of antivirulence therapy that functions by modulating expression of the PhoPR regulon and Esx-1-dependent virulence.
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Skelton LA, Boron WF. Effect of acute acid-base disturbances on the phosphorylation of phospholipase C-γ1 and Erk1/2 in the renal proximal tubule. Physiol Rep 2015; 3:e12280. [PMID: 25780091 PMCID: PMC4393148 DOI: 10.14814/phy2.12280] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 11/20/2014] [Accepted: 11/24/2014] [Indexed: 11/24/2022] Open
Abstract
The renal proximal tubule (PT) plays a major role in whole-body pH homeostasis by secreting H(+) into the tubule lumen. Previous work demonstrated that PTs respond to basolateral changes in [CO2] and [HCO3-] by appropriately altering H(+) secretion-responses blocked by the ErbB inhibitor PD168393, or by eliminating signaling through AT1 angiotensin receptors. In the present study, we analyze phosphorylation of three downstream targets of both ErbBs and AT1: phospholipase C-γ1 (PLC-γ1), extracellular-regulated kinase 1 (Erk1), and Erk2. We expose rabbit PT suspensions for 5 and 20 min to our control (Ctrl) condition (5% CO2, 22 mmol/L HCO3-, pH 7.40) or one of several conditions that mimic acid-base disturbances. We found that each disturbance produces characteristic phosphorylation patterns in the three enzymes. For example, respiratory acidosis (elevated [CO2], normal [HCO3-]) at 20 min decreases PLC-γ1 phosphorylation at tyrosine-783 (relative to Ctrl). Metabolic acidosis (normal [CO2], decreased [HCO3-]) for 5 min increases Erk1 phosphorylation (p-Erk1) but not p-Erk2, whereas metabolic alkalosis (normal [CO2], elevated [HCO3-]) for 5 min decreases p-Erk1 and p-Erk2. In the presence of CO2/HCO3-, PD168393 blocks only two of eight induced decreases in phosphorylation. In two cases in which disturbances have no remarkable effects on phosphorylation, PD168393 unmasks decreases and in two others, increases. These drug effects provide insight into the roles of PD168393-sensitive kinases. Our results indicate that PLC-γ1.pY783, p-Erk1, and p-Erk2 in the PT change in characteristic ways in response to acute acid-base disturbances, and thus presumably contribute to the transduction of acid-base signals.
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Affiliation(s)
- Lara A Skelton
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Affiliation(s)
- Lonny R. Levin
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065; ,
| | - Jochen Buck
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065; ,
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Acid-base equilibrium: The best clinical approach☆. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2015. [DOI: 10.1097/01819236-201543030-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Renal acid-base regulation: new insights from animal models. Pflugers Arch 2014; 467:1623-41. [PMID: 25515081 DOI: 10.1007/s00424-014-1669-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/16/2022]
Abstract
Because majority of biological processes are dependent on pH, maintaining systemic acid-base balance is critical. The kidney contributes to systemic acid-base regulation, by reabsorbing HCO3 (-) (both filtered by glomeruli and generated within a nephron) and acidifying urine. Abnormalities in those processes will eventually lead to a disruption in systemic acid-base balance and provoke metabolic acid-base disorders. Research over the past 30 years advanced our understanding on cellular and molecular mechanisms responsible for those processes. In particular, a variety of transgenic animal models, where target genes are deleted either globally or conditionally, provided significant insights into how specific transporters are contributing to the renal acid-base regulation. Here, we broadly overview the mechanisms of renal ion transport participating to acid-base regulation, with emphasis on data obtained from transgenic mice models.
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Tresguerres M, Barott KL, Barron ME, Roa JN. Established and potential physiological roles of bicarbonate-sensing soluble adenylyl cyclase (sAC) in aquatic animals. ACTA ACUST UNITED AC 2014; 217:663-72. [PMID: 24574382 DOI: 10.1242/jeb.086157] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Soluble adenylyl cyclase (sAC) is a recently recognized source of the signaling molecule cyclic AMP (cAMP) that is genetically and biochemically distinct from the classic G-protein-regulated transmembrane adenylyl cyclases (tmACs). Mammalian sAC is distributed throughout the cytoplasm and it may be present in the nucleus and inside mitochondria. sAC activity is directly stimulated by HCO3(-), and sAC has been confirmed to be a HCO3(-) sensor in a variety of mammalian cell types. In addition, sAC can functionally associate with carbonic anhydrases to act as a de facto sensor of pH and CO2. The two catalytic domains of sAC are related to HCO3(-)-regulated adenylyl cyclases from cyanobacteria, suggesting the cAMP pathway is an evolutionarily conserved mechanism for sensing CO2 levels and/or acid/base conditions. Reports of sAC in aquatic animals are still limited but are rapidly accumulating. In shark gills, sAC senses blood alkalosis and triggers compensatory H(+) absorption. In the intestine of bony fishes, sAC modulates NaCl and water absorption. And in sea urchin sperm, sAC may participate in the initiation of flagellar movement and in the acrosome reaction. Bioinformatics and RT-PCR results reveal that sAC orthologs are present in most animal phyla. This review summarizes the current knowledge on the physiological roles of sAC in aquatic animals and suggests additional functions in which sAC may be involved.
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Affiliation(s)
- Martin Tresguerres
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Crucho CIC. Stimuli-responsive polymeric nanoparticles for nanomedicine. ChemMedChem 2014; 10:24-38. [PMID: 25319803 DOI: 10.1002/cmdc.201402290] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/17/2014] [Indexed: 12/28/2022]
Abstract
Nature continues to be the ultimate in nanotechnology, where polymeric nanometer-scale architectures play a central role in biological systems. Inspired by the way nature forms functional supramolecular assemblies, researchers are trying to make nanostructures and to incorporate these into macrostructures as nature does. Recent advances and progress in nanoscience have demonstrated the great potential that nanomaterials have for applications in healthcare. In the realm of drug delivery, nanomaterials have been used in vivo to protect the drug entity in the systemic circulation, ensuring reproducible absorption of bioactive molecules that do not naturally penetrate biological barriers, restricting drug access to specific target sites. Several building blocks have been used in the formulation of nanoparticles. Thus, stability, drug release, and targeting can be tailored by surface modification. Herein the state of the art of stimuli-responsive polymeric nanoparticles are reviewed. Such systems are able to control drug release by reacting to naturally occurring or external applied stimuli. Special attention is paid to the design and nanoparticle formulation of these so-called smart drug-delivery systems. Future strategies for further developments of a promising controlled drug delivery responsive system are also outlined.
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Affiliation(s)
- Carina I C Crucho
- Department of Chemistry REQUIMTE/CQFB, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal).
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