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Tutol J, Ong WSY, Phelps SM, Peng W, Goenawan H, Dodani SC. Engineering the ChlorON Series: Turn-On Fluorescent Protein Sensors for Imaging Labile Chloride in Living Cells. ACS CENTRAL SCIENCE 2024; 10:77-86. [PMID: 38292617 PMCID: PMC10823515 DOI: 10.1021/acscentsci.3c01088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/02/2023] [Accepted: 11/27/2023] [Indexed: 02/01/2024]
Abstract
Beyond its role as the "queen of electrolytes", chloride can also serve as an allosteric regulator or even a signaling ion. To illuminate this essential anion across such a spectrum of biological processes, researchers have relied on fluorescence imaging with genetically encoded sensors. In large part, these have been derived from the green fluorescent protein found in the jellyfish Aequorea victoria. However, a standalone sensor with a turn-on intensiometric response at physiological pH has yet to be reported. Here, we address this technology gap by building on our discovery of the anion-sensitive fluorescent protein mNeonGreen (mNG). The targeted engineering of two non-coordinating residues, namely K143 and R195, in the chloride binding pocket of mNG coupled with an anion walking screening and selection strategy resulted in the ChlorON sensors: ChlorON-1 (K143W/R195L), ChlorON-2 (K143R/R195I), and ChlorON-3 (K143R/R195L). In vitro spectroscopy revealed that all three sensors display a robust turn-on fluorescence response to chloride (20- to 45-fold) across a wide range of affinities (Kd ≈ 30-285 mM). We further showcase how this unique sensing mechanism can be exploited to directly image labile chloride transport with spatial and temporal resolution in a cell model overexpressing the cystic fibrosis transmembrane conductance regulator. Building from this initial demonstration, we anticipate that the ChlorON technology will have broad utility, accelerating the path forward for fundamental and translational aspects of chloride biology.
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Affiliation(s)
- Jasmine
N. Tutol
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Whitney S. Y. Ong
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shelby M. Phelps
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Weicheng Peng
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Helen Goenawan
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Sheel C. Dodani
- Department
of Chemistry and Biochemistry and Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas 75080, United States
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2
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The mechanisms of chromogranin B-regulated Cl- homeostasis. Biochem Soc Trans 2022; 50:1659-1672. [PMID: 36511243 DOI: 10.1042/bst20220435] [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: 10/03/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022]
Abstract
Chloride is the most abundant inorganic anions in almost all cells and in human circulation systems. Its homeostasis is therefore important for systems physiology and normal cellular activities. This topic has been extensively studied with chloride loaders and extruders expressed in both cell surfaces and intracellular membranes. With the newly discovered, large-conductance, highly selective Cl- channel formed by membrane-bound chromogranin B (CHGB), which differs from all other known anion channels of conventional transmembrane topology, and is distributed in plasma membranes, endomembrane systems, endosomal, and endolysosomal compartments in cells expressing it, we will discuss the potential physiological importance of the CHGB channels to Cl- homeostasis, cellular excitability and volume control, and cation uptake or release at the cellular and subcellular levels. These considerations and CHGB's association with human diseases make the CHGB channel a possible druggable target for future molecular therapeutics.
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3
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Jimenez C, Hawn MB, Akin E, Leblanc N. Translational potential of targeting Anoctamin-1-Encoded Calcium-Activated chloride channels in hypertension. Biochem Pharmacol 2022; 206:115320. [PMID: 36279919 DOI: 10.1016/j.bcp.2022.115320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/13/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Calcium-activated chloride channels (CaCC) provide a depolarizing stimulus to a variety of tissues through chloride efflux in response to a rise in internal Ca2+ and voltage. One of these channels, Anoctamin-1 (ANO1 or TMEM16A) is now recognized to play a central role in promoting smooth muscle tone in various types of blood vessels. Its role in hypertension, and thus the therapeutic promise of targeting ANO1, is less straightforward. This review gives an overview of our current knowledge about the potential role ANO1 may play in hypertension within the systemic, portal, and pulmonary vascular systems and the importance of this information when pursuing potential treatment strategies. While the role of ANO1 is well-established in several forms of pulmonary hypertension, its contributions to both the generation of vascular tone and its role in hypertension within the systemic and portal systems are much less clear. This, combined with ANO1's various roles throughout a multitude of tissues throughout the body, command caution when targeting ANO1 as a therapeutic target and may require tissue-selective strategies.
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Affiliation(s)
- Connor Jimenez
- Department of Pharmacology and Center of Biomedical Research Excellence (COBRE) for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, Nevada 89557, USA
| | - Matthew B Hawn
- Department of Pharmacology and Center of Biomedical Research Excellence (COBRE) for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, Nevada 89557, USA
| | - Elizabeth Akin
- Department of Pharmacology and Center of Biomedical Research Excellence (COBRE) for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, Nevada 89557, USA
| | - Normand Leblanc
- Department of Pharmacology and Center of Biomedical Research Excellence (COBRE) for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, Nevada 89557, USA.
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4
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Liu J, Li X, Xu N, Han H, Li X. Role of ion channels in the mechanism of proteinuria (Review). Exp Ther Med 2022; 25:27. [PMID: 36561615 PMCID: PMC9748662 DOI: 10.3892/etm.2022.11726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
Abstract
Proteinuria is a common clinical manifestation of kidney diseases, such as glomerulonephritis, nephrotic syndrome, immunoglobulin A nephropathy and diabetic nephropathy. Therefore, proteinuria is considered to be a risk factor for renal dysfunction. Furthermore, proteinuria is also significantly associated with the progression of kidney diseases and increased mortality. Its occurrence is closely associated with damage to the structure of the glomerular filtration membrane. An impaired glomerular filtration membrane can affect the selective filtration function of the kidneys; therefore, several macromolecular substances, such as proteins, may pass through the filtration membrane and promote the manifestation of proteinuria. It has been reported that ion channels play a significant role in the mechanisms underlying proteinuria. Ion channel mutations or other dysfunctions have been implicated in several diseases, therefore ion channels could be used as major therapeutic targets. The mechanisms underlying the action of ion channels and ion transporters in proteinuria have been overlooked in the literature, despite their importance in identifying novel targets for treating proteinuria and delaying the progression of kidney diseases. The current review article focused on the four key ion channel groups, namely Na+, Ca2+, Cl- and K+ ion channels and the associated ion transporters.
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Affiliation(s)
- Jie Liu
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Xuewei Li
- Department of Rheumatology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Ning Xu
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Huirong Han
- Department of Anesthesiology, Weifang Medical University, Weifang, Shandong 261000, P.R. China
| | - Xiangling Li
- Department of Nephrology, Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261000, P.R. China,Correspondence to: Professor Xiangling Li, Department of Nephrology, Affiliated Hospital of Weifang Medical University, 2428 Yu He Road, Weifang, Shandong 261000, P.R. China
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5
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Yan P, Ke B, Fang X. Ion channels as a therapeutic target for renal fibrosis. Front Physiol 2022; 13:1019028. [PMID: 36277193 PMCID: PMC9581181 DOI: 10.3389/fphys.2022.1019028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Renal ion channel transport and electrolyte disturbances play an important role in the process of functional impairment and fibrosis in the kidney. It is well known that there are limited effective drugs for the treatment of renal fibrosis, and since a large number of ion channels are involved in the renal fibrosis process, understanding the mechanisms of ion channel transport and the complex network of signaling cascades between them is essential to identify potential therapeutic approaches to slow down renal fibrosis. This review summarizes the current work of ion channels in renal fibrosis. We pay close attention to the effect of cystic fibrosis transmembrane conductance regulator (CFTR), transmembrane Member 16A (TMEM16A) and other Cl− channel mediated signaling pathways and ion concentrations on fibrosis, as well as the various complex mechanisms for the action of Ca2+ handling channels including Ca2+-release-activated Ca2+ channel (CRAC), purinergic receptor, and transient receptor potential (TRP) channels. Furthermore, we also focus on the contribution of Na+ transport such as epithelial sodium channel (ENaC), Na+, K+-ATPase, Na+-H+ exchangers, and K+ channels like Ca2+-activated K+ channels, voltage-dependent K+ channel, ATP-sensitive K+ channels on renal fibrosis. Proposed potential therapeutic approaches through further dissection of these mechanisms may provide new therapeutic opportunities to reduce the burden of chronic kidney disease.
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6
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TTYH family members form tetrameric complexes at the cell membrane. Commun Biol 2022; 5:886. [PMID: 36042377 PMCID: PMC9427776 DOI: 10.1038/s42003-022-03862-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 08/18/2022] [Indexed: 11/08/2022] Open
Abstract
The conserved Tweety homolog (TTYH) family consists of three paralogs in vertebrates, displaying a ubiquitous expression pattern. Although considered as ion channels for almost two decades, recent structural and functional analyses refuted this role. Intriguingly, while all paralogs shared a dimeric stoichiometry following detergent solubilization, their structures revealed divergence in their relative subunit orientation. Here, we determined the stoichiometry of intact mouse TTYH (mTTYH) complexes in cells. Using cross-linking and single-molecule fluorescence microscopy, we demonstrate that mTTYH1 and mTTYH3 form tetramers at the plasma membrane, stabilized by interactions between their extracellular domains. Using blue-native PAGE, fluorescence-detection size-exclusion chromatography, and hydrogen/deuterium exchange mass spectrometry (HDX-MS), we reveal that detergent solubilization results in tetramers destabilization, leading to their dissolution into dimers. Moreover, HDX-MS demonstrates that the extracellular domains are stabilized in the context of the tetrameric mTTYH complex. Together, our results expose the innate tetrameric organization of TTYH complexes at the cell membrane. Future structural analyses of these assemblies in native membranes are required to illuminate their long-sought cellular function.
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7
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Zhu J, Wang XD, Luo J, Ao YF, Wang QQ, Wang DX. Cation-chloride cotransport mediated by an ion pair transporter. Org Biomol Chem 2021; 19:8586-8590. [PMID: 34559872 DOI: 10.1039/d1ob01617b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion transport mediated by an ion pair receptor 1 bearing both cation and anion binding sites is presented. The ion pair binding property was revealed by means of 1H NMR titrations in organic solutions and X-ray analysis in the solid state. Single crystal structures demonstrated that 1 and CaI2 formed a solvent-separated ion-pair complex with two iodides each interacting with a triazine ring through anion-π interactions, whereas the calcium ion is bound by a pentaethylene glycol moiety. The ion transport activity was studied by monitoring the efflux of ions from salt-loaded EYPC large unilamellar vesicles (EYPC-LUVs) using ion selective electrodes. Chloride transport across the membrane mediated by the ion pair receptor through K+/Cl- or Na+/Cl- cotransport with a selectivity towards the K+/Cl- symport was realized.
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Affiliation(s)
- Jun Zhu
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xu-Dong Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Jian Luo
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Yu-Fei Ao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi-Qiang Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - De-Xian Wang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. .,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Chen C, Tutol JN, Tang L, Zhu L, Ong WSY, Dodani SC, Fang C. Excitation ratiometric chloride sensing in a standalone yellow fluorescent protein is powered by the interplay between proton transfer and conformational reorganization. Chem Sci 2021; 12:11382-11393. [PMID: 34667546 PMCID: PMC8447875 DOI: 10.1039/d1sc00847a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Natural and laboratory-guided evolution has created a rich diversity of fluorescent protein (FP)-based sensors for chloride (Cl−). To date, such sensors have been limited to the Aequorea victoria green fluorescent protein (avGFP) family, and fusions with other FPs have unlocked ratiometric imaging applications. Recently, we identified the yellow fluorescent protein from jellyfish Phialidium sp. (phiYFP) as a fluorescent turn-on, self-ratiometric Cl− sensor. To elucidate its working mechanism as a rare example of a single FP with this capability, we tracked the excited-state dynamics of phiYFP using femtosecond transient absorption (fs-TA) spectroscopy and target analysis. The photoexcited neutral chromophore undergoes bifurcated pathways with the twisting-motion-induced nonradiative decay and barrierless excited-state proton transfer. The latter pathway yields a weakly fluorescent anionic intermediate , followed by the formation of a red-shifted fluorescent state that enables the ratiometric response on the tens of picoseconds timescale. The redshift results from the optimized π–π stacking between chromophore Y66 and nearby Y203, an ultrafast molecular event. The anion binding leads to an increase of the chromophore pKa and ESPT population, and the hindrance of conversion. The interplay between these two effects determines the turn-on fluorescence response to halides such as Cl− but turn-off response to other anions such as nitrate as governed by different binding affinities. These deep mechanistic insights lay the foundation for guiding the targeted engineering of phiYFP and its derivatives for ratiometric imaging of cellular chloride with high selectivity. We discovered an interplay between proton transfer and conformational reorganization that powers a standalone fluorescent-protein-based excitation-ratiometric biosensor for chloride imaging.![]()
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Longteng Tang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
| | - Whitney S Y Ong
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas 800 West Campbell Road Richardson TX 75080 USA https://lab.utdallas.edu/dodani/
| | - Chong Fang
- Department of Chemistry, Oregon State University 153 Gilbert Hall Corvallis OR 97331-4003 USA https://fanglab.oregonstate.edu/
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9
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Scott KM, Harmer TL, Gemmell BJ, Kramer AM, Sutter M, Kerfeld CA, Barber KS, Bari S, Boling JW, Campbell CP, Gallard-Gongora JF, Jackson JK, Lobos A, Mounger JM, Radulovic PW, Sanson JM, Schmid S, Takieddine C, Warlick KF, Whittaker R. Ubiquity and functional uniformity in CO2 concentrating mechanisms in multiple phyla of Bacteria is suggested by a diversity and prevalence of genes encoding candidate dissolved inorganic carbon transporters. FEMS Microbiol Lett 2021; 367:5863185. [PMID: 32589217 DOI: 10.1093/femsle/fnaa106] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/23/2020] [Indexed: 12/15/2022] Open
Abstract
Autotrophic microorganisms catalyze the entry of dissolved inorganic carbon (DIC; = CO2 + HCO3- + CO32-) into the biological component of the global carbon cycle, despite dramatic differences in DIC abundance and composition in their sometimes extreme environments. "Cyanobacteria" are known to have CO2 concentrating mechanisms (CCMs) to facilitate growth under low CO2 conditions. These CCMs consist of carboxysomes, containing enzymes ribulose 1,5-bisphosphate oxygenase and carbonic anhydrase, partnered to DIC transporters. CCMs and their DIC transporters have been studied in a handful of other prokaryotes, but it was not known how common CCMs were beyond "Cyanobacteria". Since it had previously been noted that genes encoding potential transporters were found neighboring carboxysome loci, α-carboxysome loci were gathered from bacterial genomes, and potential transporter genes neighboring these loci are described here. Members of transporter families whose members all transport DIC (CHC, MDT and Sbt) were common in these neighborhoods, as were members of the SulP transporter family, many of which transport DIC. 109 of 115 taxa with carboxysome loci have some form of DIC transporter encoded in their genomes, suggesting that CCMs consisting of carboxysomes and DIC transporters are widespread not only among "Cyanobacteria", but also among members of "Proteobacteria" and "Actinobacteria".
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Affiliation(s)
- Kathleen M Scott
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Tara L Harmer
- Biology Program, Stockton University, Galloway, NJ, USA
| | - Bradford J Gemmell
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Andrew M Kramer
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Markus Sutter
- Environmental Genomics and Systems Biology and Molecular Biophysics and Integrated Bioimaging Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.,Environmental Genomics and Systems Biology and Molecular Biophysics and Integrated Bioimaging Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kourtney S Barber
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Saaurav Bari
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Joshua W Boling
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Cassandra P Campbell
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | | | - Jessica K Jackson
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Aldo Lobos
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Jeannie M Mounger
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Peter W Radulovic
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Jacqueline M Sanson
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Sarah Schmid
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Candice Takieddine
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Kiley F Warlick
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
| | - Robert Whittaker
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620 USA
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10
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Mendes AF, Goncalves P, Serrano-Solis V, Silva PMD. Identification of candidate microRNAs from Ostreid herpesvirus-1 (OsHV-1) and their potential role in the infection of Pacific oysters (Crassostrea gigas). Mol Immunol 2020; 126:153-164. [PMID: 32853878 DOI: 10.1016/j.molimm.2020.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/21/2022]
Abstract
Oyster production is an economic activity of great interest worldwide. Recently, oysters have been suffering significant mortalities from OsHV-1infection, which has resulted in substantial economic loses in several countries around the world. Understanding viral pathogenicity mechanisms is of central importance for the establishment of disease control measures. Thus, the present work aimed to identify and characterize miRNAs from OsHV-1 as well as to predict their target transcripts in the virus and the host. OsHV-1 genome was used for the in silico discovery of pre-miRNAs. Subsequently, viral and host target transcripts of the OsHV-1 miRNAs were predicted according to the base pairing interaction between mature miRNAs and mRNA 3' untranslated regions (UTRs). Six unique pre-miRNAs were found in different regions of the viral genome, ranging in length from 85 to 172 nucleotides. A complex network of self-regulation of viral gene expression mediated by the miRNAs was identified. These sequences also seem to have a broad ability to regulate the expression of host immune-related genes, especially those associated with pathogen recognition. Our results suggest that OsHV-1 encodes miRNAs with important functions in the infection process, inducing self-regulation of viral transcripts, as well as affecting the regulation of Pacific oyster transcripts related to immunity. Understanding the molecular basis of host-pathogen interactions can help mitigate the recurrent events of oyster mass mortalities by OsHV-1 observed worldwide.
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Affiliation(s)
- Andrei Félix Mendes
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil
| | - Priscila Goncalves
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK
| | - Victor Serrano-Solis
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil
| | - Patricia Mirella da Silva
- Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba (UFPB), 58051-900, João Pessoa, Paraíba, Brazil.
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11
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New opportunities and challenges of venom-based and bacteria-derived molecules for anticancer targeted therapy. Semin Cancer Biol 2020; 80:356-369. [PMID: 32846203 DOI: 10.1016/j.semcancer.2020.08.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 12/24/2022]
Abstract
Due to advances in detection and treatment of cancer, especially the rise in the targeted therapy, the five-year relative survival rate of all cancers has increased significantly. However, according to the analysis of the survival rate of cancer patients in 2019, the survival rate of most cancers is still less than five years. Therefore, to combat complex cancer and further improve the 5-year survival rate of cancer patients, it is necessary to develop some new anticancer drugs. Because of the adaptive evolution of toxic species for millions of years, the venom sac is a "treasure bank", which has millions of biomolecules with high affinity and stability awaiting further development. Complete utilization of venom-based and bacteria-derived drugs in the market is still staggering because of incomplete understanding regarding their mode of action. In this review, we focused on the currently identified targets for anticancer effects based on venomous and bacterial biomolecules, such as ion channels, membrane non-receptor molecules, integrins, and other related target molecules. This review will serve as the key for exploring the molecular mechanisms behind the anticancer potential of venom-based and bacteria-derived drugs and will also lay the path for the development of anticancer targeted therapy.
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12
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Diuba AV, Samigullin DV, Kaszas A, Zonfrillo F, Malkov A, Petukhova E, Casini A, Arosio D, Esclapez M, Gross CT, Bregestovski P. CLARITY analysis of the Cl/pH sensor expression in the brain of transgenic mice. Neuroscience 2019; 439:181-194. [PMID: 31302264 DOI: 10.1016/j.neuroscience.2019.07.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 10/26/2022]
Abstract
Genetically encoded biosensors are widely used in cell biology for the non-invasive imaging of concentrations of ions or the activity of enzymes, to evaluate the distribution of small molecules, proteins and organelles, and to image protein interactions in living cells. These fluorescent molecules can be used either by transient expression in cultured cells or in entire organisms or through stable expression by producing transgenic animals characterized by genetically encoded and heritable biosensors. Using the mouse Thy1 mini-promoter, we generated a line of transgenic mice expressing a genetically encoded sensor for the simultaneous measurements of intracellular Cl- and pH. This construct, called ClopHensor, consists of a H+- and Cl--sensitive variant of the enhanced green fluorescent protein (E2GFP) fused with a red fluorescent protein (DsRedm). Stimulation of hippocampal Schaffer collaterals proved that the sensor is functionally active. To reveal the expression pattern of ClopHensor across the brain of Thy1::ClopHensor mice, we obtained transparent brain samples using the CLARITY method and imaged them with confocal and light-sheet microscopy. We then developed a semi-quantitative approach to identify brain structures with high intrinsic sensor fluorescence. This approach allowed us to assess cell morphology and track axonal projection, as well as to confirm E2GFP and DsRedm fluorescence colocalization. This analysis also provides a map of the brain areas suitable for non-invasive monitoring of intracellular Cl-/pH in normal and pathological conditions. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Artem V Diuba
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, 119992, Moscow, Russia
| | - Dmitry V Samigullin
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111, Kazan, Russia; Department of Radiophotonics and microwave technologies, Kazan National Research Technical University named after A.N.Tupolev, 420111, Kazan, Russia; Open Laboratory of Neuropharmacology, Kazan Federal University,420111, Kazan, Russia
| | - Attila Kaszas
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix- Marseille Université, 13005 Marseille, France
| | - Francesca Zonfrillo
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, EMBL-Rome, Via Ramarini 32, 00015 Monterotondo, ITALY
| | - Anton Malkov
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290, Pushchino, Russia
| | - Elena Petukhova
- Institute of Neurosciences, Kazan Medical State University, Kazan, Russia
| | | | - Daniele Arosio
- Institute of Biophysics, National Research Council of Italy, 38123 Trento, Italy
| | - Monique Esclapez
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France
| | - Cornelius T Gross
- Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, EMBL-Rome, Via Ramarini 32, 00015 Monterotondo, ITALY
| | - Piotr Bregestovski
- Aix-Marseille University, INSERM, INS, Institut of System Neurosciences, 13005 Marseille, France; Institute of Neurosciences, Kazan Medical State University, Kazan, Russia.
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13
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Tutol JN, Peng W, Dodani SC. Discovery and Characterization of a Naturally Occurring, Turn-On Yellow Fluorescent Protein Sensor for Chloride. Biochemistry 2018; 58:31-35. [PMID: 30461266 DOI: 10.1021/acs.biochem.8b00928] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fluorescent proteins have been extensively engineered and applied as optical indicators for chloride in a variety of biological contexts. Surprisingly, given the biodiversity of fluorescent proteins, a naturally occurring chloride sensor has not been reported to date. Here, we present the identification and spectroscopic characterization of the yellow fluorescent protein from the jellyfish Phialidium sp . (phiYFP), a rare example of a naturally occurring, excitation ratiometric, and turn-on fluorescent protein sensor for chloride. Our results show that chloride binding tunes the p Ka of the chromophore Y66 and shifts the equilibrium from the fluorescent phenolate form to the weakly fluorescent phenol form. The latter likely undergoes excited-state proton transfer to generate a turn-on fluorescence response that is pH-dependent. Moreover, anion selectivity and mutagenesis in the chloride binding pocket provide additional evidence for the proposed chloride sensing mechanism. Given these properties, we anticipate that phiYFP, with further engineering, could be a new tool for imaging cellular chloride dynamics.
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14
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Zhou J, Benito-Martin A, Mighty J, Chang L, Ghoroghi S, Wu H, Wong M, Guariglia S, Baranov P, Young M, Gharbaran R, Emerson M, Mark MT, Molina H, Canto-Soler MV, Selgas HP, Redenti S. Retinal progenitor cells release extracellular vesicles containing developmental transcription factors, microRNA and membrane proteins. Sci Rep 2018; 8:2823. [PMID: 29434302 PMCID: PMC5809580 DOI: 10.1038/s41598-018-20421-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 01/15/2018] [Indexed: 12/27/2022] Open
Abstract
A range of cell types, including embryonic stem cells, neurons and astrocytes have been shown to release extracellular vesicles (EVs) containing molecular cargo. Across cell types, EVs facilitate transfer of mRNA, microRNA and proteins between cells. Here we describe the release kinetics and content of EVs from mouse retinal progenitor cells (mRPCs). Interestingly, mRPC derived EVs contain mRNA, miRNA and proteins associated with multipotency and retinal development. Transcripts enclosed in mRPC EVs, include the transcription factors Pax6, Hes1, and Sox2, a mitotic chromosome stabilizer Ki67, and the neural intermediate filaments Nestin and GFAP. Proteomic analysis of EV content revealed retinogenic growth factors and morphogen proteins. mRPC EVs were shown to transfer GFP mRNA between cell populations. Finally, analysis of EV mediated functional cargo delivery, using the Cre-loxP recombination system, revealed transfer and uptake of Cre+ EVs, which were then internalized by target mRPCs activating responder loxP GFP expression. In summary, the data supports a paradigm of EV genetic material encapsulation and transfer within RPC populations. RPC EV transfer may influence recipient RPC transcriptional and post-transcriptional regulation, representing a novel mechanism of differentiation and fate determination during retinal development.
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Affiliation(s)
- Jing Zhou
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA.,Biology Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA
| | - Alberto Benito-Martin
- Children's Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medical College, New York, New York, 10021, USA
| | - Jason Mighty
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA.,Biology Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA
| | - Lynne Chang
- Nikon Instruments Inc, 1300 Walt Whitman Road, Melville, NY, 11747, USA
| | - Shima Ghoroghi
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA
| | - Hao Wu
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA.,Biology Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA
| | - Madeline Wong
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA
| | - Sara Guariglia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, 722 West 168th St, New York, NY, 10032, USA
| | - Petr Baranov
- The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Michael Young
- The Schepens Eye Research Institute, Massachusetts Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA, 02114, USA
| | - Rajendra Gharbaran
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA
| | - Mark Emerson
- Biology Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA.,Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Milica Tesic Mark
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - M Valeria Canto-Soler
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Hector Peinado Selgas
- Children's Cancer and Blood Foundation Laboratories, Departments of Pediatrics, and Cell and Developmental Biology, Drukier Institute for Children's Health, Meyer Cancer Center, Weill Cornell Medical College, New York, New York, 10021, USA.,Microenvironment and Metastasis Laboratory, Department of Molecular Oncology, Spanish National Cancer Research Centre (CNIO), Melchor Fernández Almagro, 3, Madrid, E28029, Spain
| | - Stephen Redenti
- Department of Biological Sciences, Lehman College, City University of New York, 250 Bedford Park Boulevard West, Bronx, NY, 10468, USA. .,Biology Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA. .,Biochemistry Doctoral Program, The Graduate School and University Center, City University of New York, 365 5th Avenue, New York, NY, 10016, USA.
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15
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Lin EC, Combe CL, Gasparini S. Differential Contribution of Ca 2+-Dependent Mechanisms to Hyperexcitability in Layer V Neurons of the Medial Entorhinal Cortex. Front Cell Neurosci 2017; 11:182. [PMID: 28713246 PMCID: PMC5491848 DOI: 10.3389/fncel.2017.00182] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 06/13/2017] [Indexed: 11/13/2022] Open
Abstract
Temporal lobe epilepsy is characterized by recurrent seizures in one or both temporal lobes of the brain; some in vitro models show that epileptiform discharges initiate in entorhinal layer V neurons and then spread into other areas of the temporal lobe. We previously found that, in the presence of GABAA receptor antagonists, stimulation of afferent fibers, terminating both at proximal and distal dendritic locations, initiated hyperexcitable bursts in layer V medial entorhinal neurons. We investigated the differential contribution of Ca2+-dependent mechanisms to the plateaus underlying these bursts at proximal and distal synapses. We found that the NMDA glutamatergic antagonist D,L-2-amino-5-phosphonovaleric acid (APV; 50 μM) reduced both the area and duration of the bursts at both proximal and distal synapses by about half. The L-type Ca2+ channel blocker nimodipine (10 μM) and the R- and T-type Ca2+ channel blocker NiCl2 (200 μM) decreased the area of the bursts to a lesser extent; none of these effects appeared to be location-dependent. Remarkably, the perfusion of flufenamic acid (FFA; 100 μM), to block Ca2+-activated non-selective cation currents (ICAN) mediated by transient receptor potential (TRP) channels, had a location-dependent effect, by abolishing burst firing and switching the suprathreshold response to a single action potential (AP) for proximal stimulation, but only minimally affecting the bursts evoked by distal stimulation. A similar outcome was found when FFA was pressure-applied locally around the proximal dendrite of the recorded neurons and in the presence of a selective blocker of melastatin TRP (TRPM) channels, 9-phenanthrol (100 μM), whereas a selective blocker of canonical TRP (TRPC) channels, SKF 96365, did not affect the bursts. These results indicate that different mechanisms might contribute to the initiation of hyperexcitability in layer V neurons at proximal and distal synapses and could shed light on the initiation of epileptiform activity in the entorhinal cortex.
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Affiliation(s)
- Eric C Lin
- Neuroscience Center of Excellence, Louisiana State University Health Sciences CenterNew Orleans, LA, United States
| | - Crescent L Combe
- Neuroscience Center of Excellence, Louisiana State University Health Sciences CenterNew Orleans, LA, United States
| | - Sonia Gasparini
- Neuroscience Center of Excellence, Louisiana State University Health Sciences CenterNew Orleans, LA, United States.,Department of Cell Biology and Anatomy, Louisiana State University Health Sciences CenterNew Orleans, LA, United States
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16
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M De la Fuente I, Malaina I, Pérez-Samartín A, Boyano MD, Pérez-Yarza G, Bringas C, Villarroel Á, Fedetz M, Arellano R, Cortes JM, Martínez L. Dynamic properties of calcium-activated chloride currents in Xenopus laevis oocytes. Sci Rep 2017; 7:41791. [PMID: 28198817 PMCID: PMC5304176 DOI: 10.1038/srep41791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/30/2016] [Indexed: 11/18/2022] Open
Abstract
Chloride is the most abundant permeable anion in the cell, and numerous studies in the last two decades highlight the great importance and broad physiological role of chloride currents mediated anion transport. They participate in a multiplicity of key processes, as for instance, the regulation of electrical excitability, apoptosis, cell cycle, epithelial secretion and neuronal excitability. In addition, dysfunction of Cl− channels is involved in a variety of human diseases such as epilepsy, osteoporosis and different cancer types. Historically, chloride channels have been of less interest than the cation channels. In fact, there seems to be practically no quantitative studies of the dynamics of chloride currents. Here, for the first time, we have quantitatively studied experimental calcium-activated chloride fluxes belonging to Xenopus laevis oocytes, and the main results show that the experimental Cl− currents present an informational structure characterized by highly organized data sequences, long-term memory properties and inherent “crossover” dynamics in which persistent correlations arise at short time intervals, while anti-persistent behaviors become dominant in long time intervals. Our work sheds some light on the understanding of the informational properties of ion currents, a key element to elucidate the physiological functional coupling with the integrative dynamics of metabolic processes.
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Affiliation(s)
- Ildefonso M De la Fuente
- Department of Nutrition, CEBAS-CSIC Institute, Espinardo University Campus, Murcia, Spain.,Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Iker Malaina
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Alberto Pérez-Samartín
- Department of Neurosciences, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Dolores Boyano
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Gorka Pérez-Yarza
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Carlos Bringas
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - Álvaro Villarroel
- Biophysics Unit, CSIC, University of the Basque Country, UPV/EHU, Leioa, Spain
| | - María Fedetz
- Department of Biochemistry and Pharmacology, Institute of Parasitology and Biomedicine "López-Neyra", CSIC, Granada, Spain
| | - Rogelio Arellano
- Laboratory of Cellular Neurophysiology, Neurobiology Institute, UNAM, Querétaro, México
| | - Jesus M Cortes
- Department of Cell Biology and Histology, Faculty of Medicine and Dentistry, University of the Basque Country, UPV/EHU, Leioa, Spain.,BioCruces Health Research Institute, Cruces University Hospital, Barakaldo, Spain.,IKERBASQUE: The Basque Foundation for Science, Bilbao, Spain
| | - Luis Martínez
- Department of Mathematics, Faculty of Science and Technology, University of the Basque Country, UPV/EHU, Leioa, Spain
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17
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Cao XL, Zhang X, Zhang YF, Zhang YZ, Song CG, Liu F, Hu YY, Zheng MH, Han H. Expression and purification of mouse Ttyh1 fragments as antigens to generate Ttyh1-specific monoclonal antibodies. Protein Expr Purif 2016; 130:81-89. [PMID: 27678288 DOI: 10.1016/j.pep.2016.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/19/2016] [Accepted: 09/23/2016] [Indexed: 02/03/2023]
Abstract
Ttyh1 is a murine homolog of the Drosophila Tweety and is predicted as a five-pass transmembrane protein. The Ttyh1 mRNA is expressed in mouse brain tissues with a restricted pattern and in human glioma cells. Ttyh1 protein may function as a large-conductance chloride channel, however, the role of Ttyh1 in normal neural development and tumorigenesis has been largely unknown, at least partially due to the lack of effective antibodies. Here we report the expression in E. coli and purification of two recombinant Ttyh1 protein fragments corresponding to one of the predicted extracellular domains and the carboxyl terminus of the mouse Ttyh1. With these Ttyh1 protein products, a set of monoclonal antibodies (mAbs) against the mouse Ttyh1 protein was established by using conventional hybridoma techniques. The specificity of the anti-Ttyh1 mAbs was determined based on their activities in Western blotting and immunofluorescent analysis using embryonic brain tissues and cultured mouse neural stem cells (NSCs). We also show that the mouse Ttyh1 protein was expressed in cultured NSCs, most likely in membrane and cytoplasm. In mouse embryonic brains, it appeared that the Ttyh1 protein was specifically expressed in the apical edge of the ventricular zone as puncta-like structures, as determined by using immunofluorescence. Taken together, our study provided a useful tool for further exploration of the biological functions and pathological significance of Ttyh1 in mice.
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Affiliation(s)
- Xiu-Li Cao
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Xing Zhang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Fei Zhang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yi-Zhe Zhang
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Chang-Geng Song
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Fan Liu
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Yi-Yang Hu
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China
| | - Min-Hua Zheng
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Hua Han
- State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, The Fourth Military Medical University, Xi'an, 710032, China; Department of Biochemistry and Molecular Biology, The Fourth Military Medical University, Xi'an, 710032, China.
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18
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Ghorai A, Achari B, Chattopadhyay P. Self-assembly of cyclic peptides and peptidomimetic macrocycles: linking structure with function. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.04.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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19
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Jeitner TM, Kalogiannis M, Krasnikov BF, Gomolin I, Peltier MR, Moran GR. Linking Inflammation and Parkinson Disease: Hypochlorous Acid Generates Parkinsonian Poisons. Toxicol Sci 2016; 151:388-402. [PMID: 27026709 DOI: 10.1093/toxsci/kfw052] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Inflammation is a common feature of Parkinson Disease and other neurodegenerative disorders. Hypochlorous acid (HOCl) is a reactive oxygen species formed by neutrophils and other myeloperoxidase-containing cells during inflammation. HOCl chlorinates the amine and catechol moieties of dopamine to produce chlorinated derivatives collectively termed chlorodopamine. Here, we report that chlorodopamine is toxic to dopaminergic neurons both in vivo and in vitro Intrastriatal administration of 90 nmol chlorodopamine to mice resulted in loss of dopaminergic neurons from the substantia nigra and decreased ambulation-results that were comparable to those produced by the same dose of the parkinsonian poison, 1-methyl-4-phenylpyridinium (MPP+). Chlorodopamine was also more toxic to differentiated SH SY5Y cells than HOCl. The basis of this selective toxicity is likely mediated by chlorodopamine uptake through the dopamine transporter, as expression of this transporter in COS-7 cells conferred sensitivity to chlorodopamine toxicity. Pharmacological blockade of the dopamine transporter also mitigated the deleterious effects of chlorodopamine in vivo The cellular actions of chlorodopamine included inactivation of the α-ketoglutarate dehydrogenase complex, as well as inhibition of mitochondrial respiration. The latter effect is consistent with inhibition of cytochrome c oxidase. Illumination at 670 nm, which stimulates cytochrome c oxidase, reversed the effects of chlorodopamine. The observed changes in mitochondrial biochemistry were also accompanied by the swelling of these organelles. Overall, our findings suggest that chlorination of dopamine by HOCl generates toxins that selectively kill dopaminergic neurons in the substantia nigra in a manner comparable to MPP+.
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Affiliation(s)
- Thomas M Jeitner
- *Department of Biochemistry and Molecular Biology, New York Medical College, Basic Science, Valhalla, NY 10595; Department of Biomedical Research
| | | | | | - Irving Gomolin
- Department of Geriatrics, Winthrop University Hospital, Mineola, NY 11501
| | | | - Graham R Moran
- Department of Chemistry and Biochemistry, University of Wisconsin - Milwaukee, Milwaukee, WI 53211
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20
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Cherkashin AP, Kolesnikova AS, Tarasov MV, Romanov RA, Rogachevskaja OA, Bystrova MF, Kolesnikov SS. Expression of calcium-activated chloride channels Ano1 and Ano2 in mouse taste cells. Pflugers Arch 2015; 468:305-19. [DOI: 10.1007/s00424-015-1751-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 02/03/2023]
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21
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Gaurav R, Bewtra AK, Agrawal DK. Chloride Channel 3 Channels in the Activation and Migration of Human Blood Eosinophils in Allergic Asthma. Am J Respir Cell Mol Biol 2015; 53:235-45. [PMID: 25514499 DOI: 10.1165/rcmb.2014-0300oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is responsible for respiratory burst in immune cells. Chloride channel 3 (CLC3) has been linked to the respiratory burst in eosinophils and neutrophils. The effect of cytokines and the involvement of CLC3 in the regulation of NADPH-dependent oxidative stress and on cytokine-mediated migration of eosinophils are not known. Human peripheral blood eosinophils were isolated from healthy individuals and from individuals with asthma by negative selection. Real-time PCR was used to detect the expression of NADPH oxidases in eosinophils. Intracellular reactive oxygen species (ROS) measurement was done with flow cytometry. Superoxide generation was measured with transforming growth factor (TGF)-β, eotaxin, and CLC3 blockers. CLC3 dependence of eosinophils in TGF-β- and eotaxin-induced migration was also examined. The messenger RNA (mRNA) transcripts of NADPH oxidase (NOX) 2, dual oxidase (DUOX) 1, and DUOX2 were detected in blood eosinophils, with very low expression of NOX1, NOX3, and NOX5 and no NOX4 mRNA. The level of NOX2 mRNA transcripts increased with disease severity in the eosinophils of subjects with asthma compared with healthy nonatopic volunteers. Change in granularity and size in eosinophils, but no change in intracellular ROS, was observed with phorbol myristate acetate (PMA). PMA, TGF-β, and eotaxin used the CLC3-dependent pathway to increase superoxide radicals. TGF-β and eotaxin induced CLC3-dependent chemotaxis of eosinophils. These findings support the requirement of CLC3 in the activation and migration of human blood eosinophils and may provide a potential novel therapeutic target to regulate eosinophil hyperactivity in allergic airway inflammation in asthma.
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Affiliation(s)
- Rohit Gaurav
- Department of Biomedical Sciences, Internal Medicine and Center of Clinical and Translational Sciences, Creighton University School of Medicine, Omaha, Nebraska
| | - Againdra K Bewtra
- Department of Biomedical Sciences, Internal Medicine and Center of Clinical and Translational Sciences, Creighton University School of Medicine, Omaha, Nebraska
| | - Devendra K Agrawal
- Department of Biomedical Sciences, Internal Medicine and Center of Clinical and Translational Sciences, Creighton University School of Medicine, Omaha, Nebraska
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22
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Peña-Münzenmayer G, Catalán MA, Kondo Y, Jaramillo Y, Liu F, Shull GE, Melvin JE. Ae4 (Slc4a9) Anion Exchanger Drives Cl- Uptake-dependent Fluid Secretion by Mouse Submandibular Gland Acinar Cells. J Biol Chem 2015; 290:10677-88. [PMID: 25745107 DOI: 10.1074/jbc.m114.612895] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 12/22/2022] Open
Abstract
Transcellular Cl(-) movement across acinar cells is the rate-limiting step for salivary gland fluid secretion. Basolateral Nkcc1 Na(+)-K(+)-2Cl(-) cotransporters play a critical role in fluid secretion by promoting the intracellular accumulation of Cl(-) above its equilibrium potential. However, salivation is only partially abolished in the absence of Nkcc1 cotransporter activity, suggesting that another Cl(-) uptake pathway concentrates Cl(-) ions in acinar cells. To identify alternative molecular mechanisms, we studied mice lacking Ae2 and Ae4 Cl(-)/HCO3 (-) exchangers. We found that salivation stimulated by muscarinic and β-adrenergic receptor agonists was normal in the submandibular glands of Ae2(-/-) mice. In contrast, saliva secretion was reduced by 35% in Ae4(-/-) mice. The decrease in salivation was not related to loss of Na(+)-K(+)-2Cl(-) cotransporter or Na(+)/H(+) exchanger activity in Ae4(-/-) mice but correlated with reduced Cl(-) uptake during β-adrenergic receptor activation of cAMP signaling. Direct measurements of Cl(-)/HCO3 (-) exchanger activity revealed that HCO3 (-)-dependent Cl(-) uptake was reduced in the acinar cells of Ae2(-/-) and Ae4(-/-) mice. Moreover, Cl(-)/HCO3 (-) exchanger activity was nearly abolished in double Ae4/Ae2 knock-out mice, suggesting that most of the Cl(-)/HCO3 (-) exchanger activity in submandibular acinar cells depends on Ae2 and Ae4 expression. In conclusion, both Ae2 and Ae4 anion exchangers are functionally expressed in submandibular acinar cells; however, only Ae4 expression appears to be important for cAMP-dependent regulation of fluid secretion.
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Affiliation(s)
- Gaspar Peña-Münzenmayer
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Marcelo A Catalán
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Yusuke Kondo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, the Department of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Kitakyushu, Fukuoka, Japan
| | - Yasna Jaramillo
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Frances Liu
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892
| | - Gary E Shull
- the Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, and
| | - James E Melvin
- From the Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, NIDCR, National Institutes of Health, Bethesda, Maryland 20892,
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23
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Hill M, Dušková M, Stárka L. Dehydroepiandrosterone, its metabolites and ion channels. J Steroid Biochem Mol Biol 2015; 145:293-314. [PMID: 24846830 DOI: 10.1016/j.jsbmb.2014.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 05/06/2014] [Accepted: 05/11/2014] [Indexed: 11/20/2022]
Abstract
This review is focused on the physiological and pathophysiological relevance of steroids influencing the activities of the central and peripheral nervous systems with regard to their concentrations in body fluids and tissues in various stages of human life like the fetal development or pregnancy. The data summarized in this review shows that DHEA and its unconjugated and sulfated metabolites are physiologically and pathophysiologically relevant in modulating numerous ion channels and participate in vital functions of the human organism. DHEA and its unconjugated and sulfated metabolites including 5α/β-reduced androstane steroids participate in various physiological and pathophysiological processes like the management of GnRH cyclic release, regulation of glandular and neurotransmitter secretions, maintenance of glucose homeostasis on one hand and insulin insensitivity on the other hand, control of skeletal muscle and smooth muscle activities including vasoregulation, promotion of tolerance to ischemia and other neuroprotective effects. In respect of prevalence of steroid sulfates over unconjugated steroids in the periphery and the opposite situation in the CNS, the sulfated androgens and androgen metabolites reach relevance in peripheral organs. The unconjugated androgens and estrogens are relevant in periphery and so much the more in the CNS due to higher concentrations of most unconjugated steroids in the CNS tissues than in circulation and peripheral organs. This article is part of a Special Issue entitled "Essential role of DHEA".
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Affiliation(s)
- M Hill
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - M Dušková
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
| | - L Stárka
- Steroid Hormone Unit, Institute of Endocrinology, Národní třída 8, Prague 116 94, Praha 1, CZ 116 94, Czech Republic.
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Gaurav R, Bewtra AK, Agrawal DK. Novel CLC3 transcript variants in blood eosinophils and increased CLC3 expression in nasal lavage and blood eosinophils of asthmatics. IMMUNITY INFLAMMATION AND DISEASE 2014; 2:205-13. [PMID: 25866628 PMCID: PMC4386915 DOI: 10.1002/iid3.36] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/11/2014] [Accepted: 09/12/2014] [Indexed: 01/21/2023]
Abstract
Eosinophilia is a characteristic feature of allergic airway inflammation and remodeling. Chloride channel-3 (CLC3) in eosinophils has been associated with superoxide generation and respiratory burst. The CLC3 gene may produce multiple transcript variants through alternative splicing. However, the presence of CLC3 variants in human eosinophils is unknown. We examined the expression of CLC3 transcript variants in peripheral blood eosinophils of allergic asthmatics and healthy individuals. Potential of these obligatory dimers to form homo- or hetero-dimers was examined in HEK293 cells co-transfected with CLC3b-GFP and CLC3e-RFP. Eosinophils were isolated from peripheral blood by negative selection. Expression of CLC3 and CLC3 transcript variants was examined by qPCR, Western blot, and immunofluorescence. Confocal micrographs were analyzed with Image J software. Higher levels of novel transcript variants of CLC3 (CLC3b and CLC3e) were found in peripheral blood eosinophils of asthmatics compared to healthy non-atopic subjects. We also found higher CLC3 protein expression in the blood and nasal lavage eosinophils of asthmatics than healthy subjects. Both membranous and intracellular CLC3 expression were observed. Also, we found the presence of both homodimers and heterodimers of CLC3b-GFP and CLC3e-RFP in HEK293 cells. Higher and differential expression of novel CLC3 transcript variants in mild-to-moderate and moderate-to-severe asthmatic eosinophils suggest their critical role in allergic asthma. Membranous and intracellular (granular) expression of CLC3 in nasal lavage and peripheral blood eosinophils suggest their involvement in the activation and migration of eosinophils in allergic asthma. Moreover, homo- and hetero-dimerization of these transcript variants may change the channel properties to exhibit these states. Presence of CLC3 variants may serve as a biomarker in allergic asthma and additional knowledge of interaction between CLC3 transcript variants and their specific role in the activation and migration of eosinophils will allow to explore novel therapeutic approach in allergic asthma.
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Affiliation(s)
- Rohit Gaurav
- Center of Clinical and Translational Sciences and Department of Biomedical Sciences, Creighton University School of Medicine Omaha, Nebraska
| | - Againdra K Bewtra
- Center of Clinical and Translational Sciences and Department of Biomedical Sciences, Creighton University School of Medicine Omaha, Nebraska
| | - Devendra K Agrawal
- Center of Clinical and Translational Sciences and Department of Biomedical Sciences, Creighton University School of Medicine Omaha, Nebraska
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25
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Horger KS, Liu H, Rao DK, Shukla S, Sept D, Ambudkar SV, Mayer M. Hydrogel-assisted functional reconstitution of human P-glycoprotein (ABCB1) in giant liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:643-53. [PMID: 25450342 DOI: 10.1016/j.bbamem.2014.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 09/17/2014] [Accepted: 10/20/2014] [Indexed: 11/24/2022]
Abstract
This paper describes the formation of giant proteoliposomes containing P-glycoprotein (P-gp) from a solution of small proteoliposomes that had been deposited and partially dried on a film of agarose. This preparation method generated a significant fraction of giant proteoliposomes that were free of internalized vesicles, making it possible to determine the accessible liposome volume. Measuring the intensity of the fluorescent substrate rhodamine 123 (Rho123) inside and outside these giant proteoliposomes determined the concentration of transported substrates of P-gp. Fitting a kinetic model to the fluorescence data revealed the rate of passive diffusion as well as active transport by reconstituted P-gp in the membrane. This approach determined estimates for the membrane permeability coefficient (Ps) of passive diffusion and rate constants of active transport (kT) by P-gp as a result of different experimental conditions. The Ps value for Rho123 was larger in membranes containing P-gp under all assay conditions than in membranes without P-gp indicating increased leakiness in the presence of reconstituted transmembrane proteins. For P-gp liposomes, the kT value was significantly higher in the presence of ATP than in its absence or in the presence of ATP and the competitive inhibitor verapamil. This difference in kT values verified that P-gp was functionally active after reconstitution and quantified the rate of active transport. Lastly, patch clamp experiments on giant proteoliposomes showed ion channel activity consistent with a chloride ion channel protein that co-purified with P-gp. Together, these results demonstrate several advantages of using giant rather than small proteoliposomes to characterize transport properties of transport proteins and ion channels.
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Affiliation(s)
- Kim S Horger
- Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109, USA
| | - Haiyan Liu
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA
| | - Divya K Rao
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA
| | - Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bethesda, MD 20814, USA
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA; Center for Computational Medicine and Bioinformatics, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bethesda, MD 20814, USA
| | - Michael Mayer
- Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA.
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26
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Mutational Consequences of Aberrant Ion Channels in Neurological Disorders. J Membr Biol 2014; 247:1083-127. [DOI: 10.1007/s00232-014-9716-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/25/2014] [Indexed: 12/25/2022]
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Jadallah KA, Kullab SM, Sanders DS. Constipation-predominant irritable bowel syndrome: A review of current and emerging drug therapies. World J Gastroenterol 2014; 20:8898-8909. [PMID: 25083062 PMCID: PMC4112860 DOI: 10.3748/wjg.v20.i27.8898] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 03/23/2014] [Accepted: 06/05/2014] [Indexed: 02/07/2023] Open
Abstract
Irritable bowel syndrome (IBS) is a highly prevalent medical condition that adversely affects patient quality of life and constitutes a significant economic burden on healthcare resources. A large proportion of patients suffer from the constipation subtype of IBS (IBS-C), most commonly afflicting older individuals and those with a lower socioeconomic status. Conventional pharmacologic and nonpharmacologic treatment options have limited efficacies and/or significant adverse events, which lead to increased long-term health care expenditures. Failure to effectively treat IBS-C patients over the past decades has largely been due to a poor understanding of disease pathophysiology, lack of a global view of the patient, and an inappropriate selection of patients and treatment endpoints in clinical trials. In recent years, however, more effective and safer drugs have been developed for the treatment of IBS-C. The advancement in the area of pharmacologic treatment is based on new knowledge of the pathophysiologic basis of IBS-C and the development of drugs with increased selectivity within pharmacologic classes with recognized efficacies. This narrative review covers the spectrum of available drugs and their mechanisms of action, as well as the efficacy and safety profiles of each as determined in relevant clinical trials that have investigated treatment options for IBS-C and chronic constipation. A brief summary of laxative-based treatment options is presented, followed by up-to-date assessments for three classes of drugs: prokinetics, prosecretory agents, and bile acid modulators.
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28
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Kempf J, Noujeim N, Schmitzer AR. 2,4,7-Triphenylbenzimidazole: the monomeric unit of supramolecular helical rod-like transmembrane transporters. RSC Adv 2014. [DOI: 10.1039/c4ra06887d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Supramolecular compact helical rod as transmembrane anion transporter.
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Affiliation(s)
- J. Kempf
- Département de Chimie
- Université de Montréal
- Montréal, Canada
| | - N. Noujeim
- Département de Chimie
- Université de Montréal
- Montréal, Canada
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den Hartog GJM, Qi S, van Tilburg JHO, Koek GH, Bast A. Superoxide anion radicals activate hepatic stellate cells after entry through chloride channels: a new target in liver fibrosis. Eur J Pharmacol 2013; 724:140-4. [PMID: 24378345 DOI: 10.1016/j.ejphar.2013.12.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/17/2013] [Accepted: 12/19/2013] [Indexed: 12/13/2022]
Abstract
It is generally accepted that reactive oxygen species (ROS) play an important role in the pathogenesis of liver fibrosis. ROS, however, constitute a group of species with varying properties making it likely that their contribution to the pathological mechanism varies. LX-2 hepatic stellate cells (HSCs) were exposed to superoxide anion radicals (O2(·-)) generated by xanthine and xanthine oxidase. To rule out that the activation of HSCs is due to hydrogen peroxide derived from O2(·-), control incubations with copper, zinc-superoxide dismutase and tempol were studied as well. Influx of O2(·-) activated HSCs, evidenced by the expression of α-smooth muscle actin and the secretion of transforming growth factor β1 and collagen. We further found that blockade of chloride channels with 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), 5-nitro-2-(3-phenylpropyl-amino) benzoic acid (NPPB) or indanyloxyacetic acid (IAA-94) prevented the increase of intracellular O2(·-) levels as well as the activation of HSCs. These findings suggest that O2(·-) is involved in the development of liver fibrosis and that entry of O2(·-), through chloride channels, in stellate cells is critical for their activation. This study provides new insight into the mechanism by which ROS induce liver fibrosis. Furthermore, our data suggest that chloride channels constitute a potential target for new anti-fibrotic drugs.
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Affiliation(s)
- Gertjan J M den Hartog
- Maastricht University, Faculty of Health, Medicine and Life Sciences, Department of Toxicology, Maastricht, The Netherlands.
| | - Shufan Qi
- Maastricht University, Faculty of Health, Medicine and Life Sciences, Department of Toxicology, Maastricht, The Netherlands
| | - Jonathan H O van Tilburg
- Maastricht University, Faculty of Health, Medicine and Life Sciences, Department of Human Biology, Maastricht, The Netherlands
| | - Ger H Koek
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Aalt Bast
- Maastricht University, Faculty of Health, Medicine and Life Sciences, Department of Toxicology, Maastricht, The Netherlands
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30
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Baier S, Krämer P, Grudzenski S, Fatar M, Kirsch S, Schad LR. Chlorine and sodium chemical shift imaging during acute stroke in a rat model at 9.4 Tesla. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2013; 27:71-9. [DOI: 10.1007/s10334-013-0398-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 07/30/2013] [Accepted: 07/31/2013] [Indexed: 11/28/2022]
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31
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Effect of Extracellular Factors on Growth and Dimorphism of Rhizopus oryzae with Multiple Enzyme Synthesizing Ability. Indian J Microbiol 2013; 52:215-21. [PMID: 23729885 DOI: 10.1007/s12088-011-0197-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Accepted: 09/29/2010] [Indexed: 10/17/2022] Open
Abstract
Rhizopus oryzae PR7 MTCC 9642 was a dimorphic fungus that showed a regular 90 days cycle of filament (mycelium) to pellet (yeast) transformation through a distinct bottom dwelling intermediate state and the pellets never revert back to filamentous form. Apart from the normal cycle, high temperature (37°C and above) and extreme pH also induced the yeast formation. Among the ions tested, calcium and chloride ions were found to restore the filamentous morphology, even in extreme pH and temperature. Cysteine HCl also played noteworthy role in maintaining mycelial growth even at adverse condition. Immobilized spores showed the appearance of intermediate form instead of typical yeast form even at high temperature. The strain could produce a number of extracellular hydrolytic enzymes like cellulolytic, xylanolytic, pectinolytic and amylolytic enzymes. The pellet and mycelial forms were found to be a better producer of cellulase-lignocellulase enzymes and amylolytic enzymes respectively, which might be correlated with their infectivity. Increase in inoculum size, agitation during cultivation, change in carbon and nitrogen source failed to induce mycelial growth in extreme conditions, which might be explained as irreversible change of configuration of protein responsible for mycelial development.
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32
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Guinamard R, Simard C, Del Negro C. Flufenamic acid as an ion channel modulator. Pharmacol Ther 2013; 138:272-84. [PMID: 23356979 DOI: 10.1016/j.pharmthera.2013.01.012] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 12/26/2012] [Indexed: 12/29/2022]
Abstract
Flufenamic acid has been known since the 1960s to have anti-inflammatory properties attributable to the reduction of prostaglandin synthesis. Thirty years later, flufenamic acid appeared to be an ion channel modulator. Thus, while its use in medicine diminished, its use in ionic channel research expanded. Flufenamic acid commonly not only affects non-selective cation channels and chloride channels, but also modulates potassium, calcium and sodium channels with effective concentrations ranging from 10(-6)M in TRPM4 channel inhibition to 10(-3)M in two-pore outwardly rectifying potassium channel activation. Because flufenamic acid effects develop and reverse rapidly, it is a convenient and widely used tool. However, given the broad spectrum of its targets, experimental results have to be interpreted cautiously. Here we provide an overview of ion channels targeted by flufenamic acid to aid in interpreting its effects at the molecular, cellular, and system levels. If it is used with good practices, flufenamic acid remains a useful tool for ion channel research. Understanding the targets of FFA may help reevaluate its physiological impacts and revive interest in its therapeutic potential.
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33
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Zhang Q, Hou M, Li Q, Han L, Yuan Z, Tan J, Du B, Zou X, Hou L. Expression patterns of As-ClC gene of Artemia sinica in early development and under salinity stress. Mol Biol Rep 2013; 40:3655-64. [PMID: 23277400 DOI: 10.1007/s11033-012-2441-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/18/2012] [Indexed: 01/05/2023]
Abstract
As-ClC (chloride channels protein from Artemia sinica), a member from the chloride channels protein family, is a α-helical membrane protein predicted to traverse the cell membrane 11 times. It is important for several physiological functions such as cell volume regulation, cell proliferation, growth and differentiation. In this paper, the complete cDNA sequence of As-CIC was cloned from A. sinica for the first time using RACE technology. The expression pattern and location of the As-CIC gene was investigated in different stages of the embryonic development by means of quantitative real-time PCR and in situ hybridization (ISH) assay. As-CLC was distributed throughout the whole body in cells of different embryonic development of A. sinica as shown by ISH. There was a low expression level of the As-ClC gene after 0 h and a higher expression level after 15 and 40 h when the embryo entered the next growth period and the environmental salinity changed. At adult stage, the As-ClC maintained a high expression level. The results of the real-time PCR assay showed an increasing trend of As-ClC transcripts with increasing salinity. The expression of As-ClC was higher in the control group (28) than in the experimental group except at a salinity of 200 PSU. It indicated that As-ClC functions as salinity-stress-related gene, probably participated in cell volume regulation and osmotic regulation during the early embryonic development of A. sinica.
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Affiliation(s)
- Qiaozhi Zhang
- College of Life Sciences, Liaoning Normal University, Dalian 116029, People's Republic of China
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34
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Matchkov VV, Secher Dam V, Bødtkjer DMB, Aalkjær C. Transport and Function of Chloride in Vascular Smooth Muscles. J Vasc Res 2013; 50:69-87. [DOI: 10.1159/000345242] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/16/2012] [Indexed: 12/12/2022] Open
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35
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Bertollini C, Murana E, Mosca L, D'Erme M, Scala F, Francioso A, Catalano M, Limatola C, Bregestovski P, Di Angelantonio S, Ragozzino D. Transient increase in neuronal chloride concentration by neuroactive aminoacids released from glioma cells. Front Mol Neurosci 2012. [PMID: 23189038 PMCID: PMC3505843 DOI: 10.3389/fnmol.2012.00100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Neuronal chloride concentration ([Cl−]i) is known to be dynamically modulated and alterations in Cl− homeostasis may occur in the brain at physiological and pathological conditions, being also likely involved in glioma-related seizures. However, the mechanism leading to changes in neuronal [Cl−]i during glioma invasion are still unclear. To characterize the potential effect of glioma released soluble factors on neuronal [Cl−]i, we used genetically encoded CFP/YFP-based ratiometric Cl-(apical) Sensor transiently expressed in cultured hippocampal neurons. Exposition of neurons to glioma conditioned medium (GCM) caused rapid and transient elevation of [Cl−]i, resulting in the increase of fluorescence ratio, which was strongly reduced by blockers of ionotropic glutamate receptors APV and NBQX. Furthermore, in HEK cells expressing GluR1-AMPA receptors, GCM activated ionic currents with efficacy similar to those caused by glutamate, supporting the notion that GCM contains glutamate or glutamatergic agonists, which cause neuronal depolarization, activation of NMDA and AMPA/KA receptors leading to elevation of [Cl−]i. Chromatographic analysis of the GCM showed that it contained several aminoacids, including glutamate, whose release from glioma cells did not occur via the most common glial mechanisms of transport, or in response to hypoosmotic stress. GCM also contained glycine, whose action contrasted the glutamate effect. Indeed, strychnine application significantly increased GCM-induced depolarization and [Cl−]i rise. GCM-evoked [Cl−]i elevation was not inhibited by antagonists of Cl− transporters and significantly reduced in the presence of anion channels blocker NPPB, suggesting that Cl− selective channels are a major route for GCM-induced Cl− influx. Altogether, these data show that glioma released aminoacids may dynamically alter Cl− equilibrium in surrounding neurons, deeply interfering with their inhibitory balance, likely leading to physiological and pathological consequences.
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Affiliation(s)
- Cristina Bertollini
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome Rome, Italy
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36
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Robertson JWF, Kasianowicz JJ, Banerjee S. Analytical Approaches for Studying Transporters, Channels and Porins. Chem Rev 2012; 112:6227-49. [DOI: 10.1021/cr300317z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Joseph W. F. Robertson
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - John J. Kasianowicz
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - Soojay Banerjee
- National
Institute of Neurological
Disorders and Stroke, Bethesda, Maryland 20824, United States
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37
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Menees S, Saad R, Chey WD. Agents that act luminally to treat diarrhoea and constipation. Nat Rev Gastroenterol Hepatol 2012; 9:661-74. [PMID: 22945441 DOI: 10.1038/nrgastro.2012.162] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Diarrhoea and constipation are common clinical complaints that negatively affect quality of life, reduce work productivity and lead to considerable health-care expenditure. A variety of therapies have been used to treat these conditions. Unlike drugs that require systemic absorption to exert their effects, luminally acting agents improve diarrhoea and constipation by altering intestinal and/or colonic motility, as well as mucosal absorption and secretion, through a variety of mechanisms. Examples of luminally acting agents for diarrhoea include peripherally acting opiate analogues, enkephalinase inhibitors, bile-acid binding agents, nonabsorbed antibiotics, probiotics, bismuth-containing compounds, berberine and agents with possible effects on intestinal secretion or permeability. Luminally acting drugs for constipation include bulking agents, surfactants, osmotics, stimulants, chloride-channel activators, probiotics, drugs that increase delivery of bile acids to the colon and natural therapies such as prunes and hemp seed extract. As the physiological effects of luminally acting drugs are largely confined to the gastrointestinal tract, these agents are unlikely to cause adverse effects outside of the gastrointestinal tract.
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Affiliation(s)
- Stacy Menees
- University of Michigan Health System, 3912 Taubman Center, SPC 5362, Ann Arbor, MI 48109-5362, USA
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38
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Cystic fibrosis: insight into CFTR pathophysiology and pharmacotherapy. Clin Biochem 2012; 45:1132-44. [PMID: 22698459 DOI: 10.1016/j.clinbiochem.2012.05.034] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 05/15/2012] [Accepted: 05/28/2012] [Indexed: 12/14/2022]
Abstract
Cystic fibrosis is the most common life-threatening recessively inherited disease in Caucasians. Due to early provision of care in specialized reference centers and more comprehensive care, survival has improved over time. Despite great advances in supportive care and in our understanding of its pathophysiology, there is still no cure for the disease. Therapeutic strategies aimed at rescuing the abnormal protein are either being sought after or under investigation. This review highlights salient insights into pathophysiology and candidate molecules suitable for CFTR pharmacotherapy. Clinical trials using Ataluren, VX-809 and ivacaftor have provided encouraging data. Preclinical data with inhibitors of phosphodiesterase type 5, such as sildenafil and analogs, have highlighted their potential for CFTR pharmacotherapy. Because sildenafil and analogs are in clinical use for other clinical applications, research on this class of drugs might speed up the development of new therapies for CF.
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39
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Hermann A, Donato R, Weiger TM, Chazin WJ. S100 calcium binding proteins and ion channels. Front Pharmacol 2012; 3:67. [PMID: 22539925 PMCID: PMC3336106 DOI: 10.3389/fphar.2012.00067] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/03/2012] [Indexed: 12/23/2022] Open
Abstract
S100 Ca(2+)-binding proteins have been associated with a multitude of intracellular Ca(2+)-dependent functions including regulation of the cell cycle, cell differentiation, cell motility and apoptosis, modulation of membrane-cytoskeletal interactions, transduction of intracellular Ca(2+) signals, and in mediating learning and memory. S100 proteins are fine tuned to read the intracellular free Ca(2+) concentration and affect protein phosphorylation, which makes them candidates to modulate certain ion channels and neuronal electrical behavior. Certain S100s are secreted from cells and are found in extracellular fluids where they exert unique extracellular functions. In addition to their neurotrophic activity, some S100 proteins modulate neuronal electrical discharge activity and appear to act directly on ion channels. The first reports regarding these effects suggested S100-mediated alterations in Ca(2+) fluxes, K(+) currents, and neuronal discharge activity. Recent reports revealed direct and indirect interactions with Ca(2+), K(+), Cl(-), and ligand activated channels. This review focuses on studies of the physical and functional interactions of S100 proteins and ion channels.
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Affiliation(s)
- Anton Hermann
- Division of Cellular and Molecular Neurobiology, Department of Cell Biology, University of SalzburgSalzburg, Austria
| | - Rosario Donato
- Department of Experimental Medicine and Biochemical Sciences, University of PerugiaPerugia, Italy
| | - Thomas M. Weiger
- Division of Cellular and Molecular Neurobiology, Department of Cell Biology, University of SalzburgSalzburg, Austria
| | - Walter J. Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt UniversityNashville, TN, USA
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40
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Soubra M, Schey R. Lubiprostone for the treatment of adult women with irritable bowel syndrome with constipation. CLINICAL MEDICINE INSIGHTS. GASTROENTEROLOGY 2012; 5:23-30. [PMID: 24833931 PMCID: PMC3987758 DOI: 10.4137/cgast.s7625] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Irritable bowel syndrome with constipation (IBS-C) affects approximately 5% of the population in western countries. The majority of those afflicted are women. Symptoms are often detrimental to the individual's quality of life and incur high healthcare costs to society. There is no evidence to support changes in lifestyle, laxatives or over the counter supplements. Tegaserod appeared to have promising results but was promptly removed from the market due to adverse cardiovascular events. In 2008, lubiprostone (Amitiza) was approved by the US Food and Drug Administration (FDA) for the treatment of women with IBS-C. It is thought to selectively activate type 2 chloride channels in the apical membrane of the intestinal epithelial cells leading to chloride secretion. As result, sodium and water are passively secreted generating peristalsis and laxation, without stimulating gastrointestinal smooth muscle. Several trials with predominantly female patients have shown it to be effective in the treatment of IBS-C. Overall lubiprostone was safe, well tolerated and associated with mostly benign side effects. Nausea and diarrhea were the most commonly reported. Though there are no head to head comparisons with other pharmacological agents, it is our opinion that lubiprostone should be tried as a first line pharmacotherapy for women with IBS-C at a dose of 8 μg BID. Thus far, lubiprostone offers a welcome approach to our narrow therapeutic armamentarium. Further understanding of its mechanism of action may provide additional insight into the pathophysiology of IBS-C.
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Affiliation(s)
- Mahmoud Soubra
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Ron Schey
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa
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41
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Orta G, Ferreira G, José O, Treviño CL, Beltrán C, Darszon A. Human spermatozoa possess a calcium-dependent chloride channel that may participate in the acrosomal reaction. J Physiol 2012; 590:2659-75. [PMID: 22473777 DOI: 10.1113/jphysiol.2011.224485] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Motility, maturation and the acrosome reaction (AR) are fundamental functions of mammalian spermatozoa. While travelling through the female reproductive tract, spermatozoa must mature through a process named capacitation, so that they can reach the egg and undergo the AR, an exocytotic event necessary to fertilize the egg. Though Cl⁻ is important for sperm capacitation and for the AR, not much is known about the molecular identity of the Cl⁻ transporters involved in these processes.We implemented a modified perforated patch-clamp strategy to obtain whole cell recordings sealing on the head of mature human spermatozoa.Our whole cell recordings revealed the presence of a Ca²⁺-dependent Cl⁻ current. The biophysical characteristics of this current and its sensitivity to niflumic acid (NFA) and 4,4-diisothiocyano-2,2-stilbene disulphonic acid (DIDIS) are consistent with those displayed by the Ca²⁺-dependent Cl⁻ channel from the anoctamin family (TMEM16). Whole cell patch clamp recordings in the cytoplasmic droplet of human spermatozoa corroborated the presence of these currents, which were sensitive to NFA and to a small molecule TMEM16A inhibitor (TMEM16Ainh, an aminophenylthiazole). Importantly, the human sperm AR induced by a recombinant human glycoprotein from the zona pellucida, rhZP3, displayed a similar sensitivity to NFA, DIDS and TMEM16Ainh as the sperm Ca²⁺-dependent Cl⁻ currents. Our findings indicate the presence of Ca²⁺-dependent Cl⁻ currents in human spermatozoa, that TMEM16A may contribute to these currents and also that sperm Ca²⁺-dependent Cl⁻ currents may participate in the rhZP3-induced AR.
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Affiliation(s)
- Gerardo Orta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, CP 62210, México
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Volknandt W, Karas M. Proteomic analysis of the presynaptic active zone. Exp Brain Res 2012; 217:449-61. [DOI: 10.1007/s00221-012-3031-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 02/04/2012] [Indexed: 02/06/2023]
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Jones SM, Palmer MJ. Pharmacological analysis of the activation and receptor properties of the tonic GABA(C)R current in retinal bipolar cell terminals. PLoS One 2011; 6:e24892. [PMID: 21949779 PMCID: PMC3174224 DOI: 10.1371/journal.pone.0024892] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 08/22/2011] [Indexed: 11/29/2022] Open
Abstract
GABAergic inhibition in the central nervous system (CNS) can occur via rapid, transient postsynaptic currents and via a tonic increase in membrane conductance, mediated by synaptic and extrasynaptic GABAA receptors (GABAARs) respectively. Retinal bipolar cells (BCs) exhibit a tonic current mediated by GABACRs in their axon terminal, in addition to synaptic GABAAR and GABACR currents, which strongly regulate BC output. The tonic GABACR current in BC terminals (BCTs) is not dependent on vesicular GABA release, but properties such as the alternative source of GABA and the identity of the GABACRs remain unknown. Following a recent report that tonic GABA release from cerebellar glial cells is mediated by Bestrophin 1 anion channels, we have investigated their role in non-vesicular GABA release in the retina. Using patch-clamp recordings from BCTs in goldfish retinal slices, we find that the tonic GABACR current is not reduced by the anion channel inhibitors NPPB or flufenamic acid but is reduced by DIDS, which decreases the tonic current without directly affecting GABACRs. All three drugs also exhibit non-specific effects including inhibition of GABA transporters. GABACR ρ subunits can form homomeric and heteromeric receptors that differ in their properties, but BC GABACRs are thought to be ρ1-ρ2 heteromers. To investigate whether GABACRs mediating tonic and synaptic currents may differ in their subunit composition, as is the case for GABAARs, we have examined the effects of two antagonists that show partial ρ subunit selectivity: picrotoxin and cyclothiazide. Tonic and synaptic GABACR currents were differentially affected by both drugs, suggesting that a population of homomeric ρ1 receptors contributes to the tonic current. These results extend our understanding of the multiple forms of GABAergic inhibition that exist in the CNS and contribute to visual signal processing in the retina.
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Affiliation(s)
- Stefanie M. Jones
- Neuroscience Group, Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom
| | - Mary J. Palmer
- Neuroscience Group, Institute for Science and Technology in Medicine, Keele University, Keele, United Kingdom
- * E-mail:
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Hong L, Xie ZZ, Du YH, Tang YB, Tao J, Lv XF, Zhou JG, Guan YY. Alteration of volume-regulated chloride channel during macrophage-derived foam cell formation in atherosclerosis. Atherosclerosis 2011; 216:59-66. [DOI: 10.1016/j.atherosclerosis.2011.01.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 12/28/2010] [Accepted: 01/24/2011] [Indexed: 11/15/2022]
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Hedden L, Benes CH, Soltoff SP. P2X(7) receptor antagonists display agonist-like effects on cell signaling proteins. Biochim Biophys Acta Gen Subj 2011; 1810:532-42. [PMID: 21397667 DOI: 10.1016/j.bbagen.2011.03.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 02/14/2011] [Accepted: 03/07/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND The activation of various P2 receptors (P2R) by extracellular nucleotides promotes diverse cellular events, including the stimulation of cell signaling protein and increases in [Ca(2+)](i). We report that some agents that can block P2X(7)R receptors also promote diverse P2X(7)R-independent effects on cell signaling. METHODS We exposed native rat parotid acinar cells, salivary gland cell lines (Par-C10, HSY, HSG), and PC12 cells to suramin, DIDS (4,4'-diisothiocyano stilbene-2,2'-disulfonic acid), Cibacron Blue 3GA, Brilliant Blue G, and the P2X(7)R-selective antagonist A438079, and examined the activation/phosphorylation of ERK1/2, PKCδ, Src, CDCP1, and other signaling proteins. RESULTS With the exception of suramin, these agents blocked the phosphorylation of ERK1/2 by BzATP in rat parotid acinar cells; but higher concentrations of suramin blocked ATP-stimulated (45)Ca(2+) entry. Aside from A438079, these agents increased the phosphorylation of ERK1/2, Src, PKCδ, and other proteins (including Dok-1) within minutes in an agent- and cell type-specific manner in the absence of a P2X(7)R ligand. The stimulatory effect of these compounds on the tyrosine phosphorylation of CDCP1 and its Src-dependent association with PKCδ was blocked by knockdown of CDCP1, which also blocked Src and PKCδ phosphorylation. CONCLUSIONS Several agents used as P2X(7)R blockers promote the activation of various signaling proteins and thereby act more like receptor agonists than antagonists. GENERAL SIGNIFICANCE Some compounds used to block P2 receptors have complicated effects that may confound their use in blocking receptor activation and other biological processes for which they are employed, including their use as blockers of various ion transport proteins.
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Affiliation(s)
- Lee Hedden
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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Saad RJ. Peripherally acting therapies for the treatment of irritable bowel syndrome. Gastroenterol Clin North Am 2011; 40:163-82. [PMID: 21333906 DOI: 10.1016/j.gtc.2010.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gut-acting therapies are common therapies for irritable bowel syndrome (IBS). Most of these peripheral acting agents are primarily targeted at individual symptoms. The evidence supporting the use of these agents in IBS is largely anecdotal. Serotonergic agents and the chloride channel activator lubiprostone have shown efficacy in treating symptoms of IBS. The clinical evidence supporting the use of these agents is based on data from high-quality clinical trials. The use of serotonergic agents for IBS in the United States is limited to the 5-hydroxytryptamine-3 antagonist alosetron in the treatment of women with severe IBS with diarrhea refractory to traditional therapy.
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Affiliation(s)
- Richard J Saad
- Division of Gastroenterology, University of Michigan Health System, 3912 Taubman Center, 1500 East Medical Center Drive, SPC 5362, Ann Arbor, MI 48109, USA.
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Chen CY, Tu TY, Jong DS, Wo AM. Ion channel electrophysiology via integrated planar patch-clamp chip with on-demand drug exchange. Biotechnol Bioeng 2011; 108:1395-403. [PMID: 21328315 DOI: 10.1002/bit.23068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 12/29/2010] [Accepted: 01/07/2011] [Indexed: 11/05/2022]
Abstract
Planar patch clamp has revolutionized characterization of ion channel behavior in drug discovery primarily via advancement in high throughput. Lab use of planar technology, however, addresses different requirements and suffers from inflexibility to enable wide range of interrogation via a single cell. This work presents integration of planar patch clamp with microfluidics, achieving multiple solution exchanges for tailor-specific measurement and allowing rapid replacement of the cell-contacting aperture. Studies via endogenously expressed ion channels in HEK 293T cells were commenced to characterize the device. Results reveal the microfluidic concentration generator produces distinct solution/drug combination/concentrations on-demand. Volume-regulated chloride channel and voltage-gated potassium channels in HEK 293T cells immersed in generated solutions under various osmolarities or drug concentrations show unique channel signature under specific condition. Excitation and blockage of ion channels in a single cell was demonstrated via serial solution exchange. Robustness of the reversible bonding and ease of glass substrate replacement were proven via repeated usage of the integrated device. The present approach reveals the capability and flexibility of integrated microfluidic planar patch-clamp system for ion channel assays.
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Affiliation(s)
- Chang-Yu Chen
- Institute of Applied Mechanics, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan
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Elie CR, Noujeim N, Pardin C, Schmitzer AR. Uncovering new properties of imidazolium salts: Cl−transport and supramolecular regulation of their transmembrane activity. Chem Commun (Camb) 2011; 47:1788-90. [DOI: 10.1039/c0cc04280c] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The membrane potential fulfils an important role in initiating smooth muscle contraction, through its depolarization and the subsequent influx of Ca(2+) through voltage-gated Ca(2+) channels. Changes in membrane potential can also coordinate contraction across great distances, utilizing the speed of electrical current flow through gap junctions. Hence, regulating membrane potential can greatly influence smooth muscle function. In this chapter, we will consider the influence of ion channels, as dynamic gatekeepers of membrane permeability, on urogenital function. Through their ability to act as key regulators of both the resting membrane potential and its dynamic changes, they provide important pharmacological targets for influencing urogenital function.Urogenital smooth muscle and urothelia contain a diverse range of molecularly and functionally distinct K(+) channels, which are key to regulating the resting membrane and for re-establishing the normal membrane potential following both active and passive changes. The voltage-gated Ca(2+) channels are key to initiating contraction and causing rapid depolarization, supplemented in some smooth muscles by rapid Na(+) conductances. The Cl(-) channels, often assumed to be passive, can actively change the membrane potential, and hence, cellular function, because Cl(-) is not usually at its equilibrium potential. The useful ways in which these ion channels can be targeted therapeutically in the ureter, bladder and urethra are discussed, focussing particularly on treatments for ureteric obstruction and detrusor overactivity. Current treatments for many urinary tract disorders, particularly the overactive bladder, are complicated by side effects. While ion channels have traditionally been considered as poor therapeutic targets by the pharmaceutical industry, our increasing knowledge of the molecular diversity of K(+) and Cl(-) channels gives new hope for more narrowly focused drug targeting, while the exciting discoveries of active currents in interstitial cells give us a new set of cellular targets for drugs.
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Affiliation(s)
- A F Brading
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK.
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Potentiation of EDHF-mediated relaxation by chloride channel blockers. Acta Pharmacol Sin 2010; 31:1303-11. [PMID: 20835269 DOI: 10.1038/aps.2010.157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
AIM To investigate the involvement of Cl⁻ channels in endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation in rat mesenteric arteries. METHODS Cl⁻ channel and K(ir) channel activities were studied using whole-cell patch clamping in rat mesenteric arterial smooth muscle cells. Isometric tension of arterial rings was measured in organ chambers. RESULTS The volume-activated Cl⁻ current in rat mesenteric arterial smooth muscle cells was abolished by Cl⁻ channel blockers NPPB or DIDS. The EDHF-mediated vasorelaxation was potentiated by NPPB and DIDS. The EDHF response was diminished by a combination of apamin and charybdotoxin, which agreed with the hypothesis that EDHF response involves the release of K(+) via the Ca²(+)-activated K(+) channels in endothelial cells. The elevation of K(+) concentration in bathing solution from 1.2 mmol/L to 11.2 mmol/L induced an arterial relaxation, which was abolished by the combination of BaCl₂ and ouabain. It is consistent to the hypothesis that K(+) activates K(+)/Na(+)-ATPase and inward rectifier K(+) (K(ir)) channels, leading to the hyperpolarization and relaxation of vascular smooth muscle. The K(+)-induced relaxation was augmented by NPPB, DIDS, or withdrawal of Cl⁻ from the bathing solution, which could be reversed by BaCl₂, but not ouabain. The potentiating effect of Cl⁻ channel blockers on K(+)-induced relaxation was probably due to the interaction between Cl⁻ channels and K(ir) channels. Moreover, the K(+)-induced relaxation was potentiated when the arteries were incubated in hyperosmotic solution, which is known to inhibit volume-activated Cl⁻ channels. CONCLUSION The inhibition of Cl⁻ channels, particularly the volume-activated Cl⁻ channels, may potentiate the EDHF-induced vasorelaxation through the K(ir) channels.
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