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Orfali R, AlFaiz A, Rahman MA, Lau L, Nam YW, Zhang M. K Ca2 and K Ca3.1 Channels in the Airways: A New Therapeutic Target. Biomedicines 2023; 11:1780. [PMID: 37509419 PMCID: PMC10376499 DOI: 10.3390/biomedicines11071780] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 07/30/2023] Open
Abstract
K+ channels are involved in many critical functions in lung physiology. Recently, the family of Ca2+-activated K+ channels (KCa) has received more attention, and a massive amount of effort has been devoted to developing selective medications targeting these channels. Within the family of KCa channels, three small-conductance Ca2+-activated K+ (KCa2) channel subtypes, together with the intermediate-conductance KCa3.1 channel, are voltage-independent K+ channels, and they mediate Ca2+-induced membrane hyperpolarization. Many KCa2 channel members are involved in crucial roles in physiological and pathological systems throughout the body. In this article, different subtypes of KCa2 and KCa3.1 channels and their functions in respiratory diseases are discussed. Additionally, the pharmacology of the KCa2 and KCa3.1 channels and the link between these channels and respiratory ciliary regulations will be explained in more detail. In the future, specific modulators for small or intermediate Ca2+-activated K+ channels may offer a unique therapeutic opportunity to treat muco-obstructive lung diseases.
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Affiliation(s)
- Razan Orfali
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
- Biomedical Research Administration, Research Centre, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh 12231, Saudi Arabia
| | - Ali AlFaiz
- Biomedical Research Administration, Research Centre, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh 12231, Saudi Arabia
| | - Mohammad Asikur Rahman
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Liz Lau
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
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2
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Bigdaj EV, Fufachev DK, Petrov PR, Samojlov VO. Mechanisms of electromechanical and electrochemical coupling in olfactory cilia of the frog (Rana temporaria). Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s0006350917020051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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3
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Carrisoza-Gaytán R, Wang L, Schreck C, Kleyman TR, Wang WH, Satlin LM. The mechanosensitive BKα/β1 channel localizes to cilia of principal cells in rabbit cortical collecting duct (CCD). Am J Physiol Renal Physiol 2016; 312:F143-F156. [PMID: 27806944 DOI: 10.1152/ajprenal.00256.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 10/12/2016] [Accepted: 10/26/2016] [Indexed: 11/22/2022] Open
Abstract
Within the CCD of the distal nephron of the rabbit, the BK (maxi K) channel mediates Ca2+- and/or stretch-dependent flow-induced K+ secretion (FIKS) and contributes to K+ adaptation in response to dietary K+ loading. An unresolved question is whether BK channels in intercalated cells (ICs) and/or principal cells (PCs) in the CCD mediate these K+ secretory processes. In support of a role for ICs in FIKS is the higher density of immunoreactive apical BKα (pore-forming subunit) and functional BK channel activity than detected in PCs, and an increase in IC BKα expression in response to a high-K+ diet. PCs possess a single apical cilium which has been proposed to serve as a mechanosensor; direct manipulation of cilia leads to increases in cell Ca2+ concentration, albeit of nonciliary origin. Immunoperfusion of isolated and fixed CCDs isolated from control K+-fed rabbits with channel subunit-specific antibodies revealed colocalization of immunodetectable BKα- and β1-subunits in cilia as well as on the apical membrane of cilia-expressing PCs. Ciliary BK channels were more easily detected in rabbits fed a low-K+ vs. high-K+ diet. Single-channel recordings of cilia revealed K+ channels with conductance and kinetics typical of the BK channel. The observations that 1) FIKS was preserved but 2) the high-amplitude Ca2+ peak elicited by flow was reduced in microperfused CCDs subject to pharmacological deciliation suggest that cilia BK channels do not contribute to K+ secretion in this segment, but that cilia serve as modulators of cell signaling.
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Affiliation(s)
| | - Lijun Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Carlos Schreck
- Servicio de Nefrologia-Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Thomas R Kleyman
- Departments of Medicine, Cell Biology, and Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York;
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4
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Lachén-Montes M, Fernández-Irigoyen J, Santamaría E. Deconstructing the molecular architecture of olfactory areas using proteomics. Proteomics Clin Appl 2016; 10:1178-1190. [PMID: 27226001 DOI: 10.1002/prca.201500147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/02/2016] [Accepted: 05/22/2016] [Indexed: 11/07/2022]
Abstract
The anatomy of the olfactory system is highly complex, comprising a system of olfactory receptors, pathways for the transmission of olfactory information, and structures for the recognition, discrimination, and memorization of odors. During the last years, proteomics has emerged as a large-scale comprehensive approach to characterize and quantify specific olfactory-related proteomes in different biological conditions such as olfactory learning, neurodegeneration, and ageing between others. The current work reviews recent applications of proteomics to olfaction with particular focus on quantitative proteome profiling studies performed on olfactory areas from laboratory animal models as well as proteomic characterizations performed on specific brain structures and fluids involved in human smell. Finally, we will also discuss the potential application of proteomics to study global proteome dynamics and posttranslationally modified proteomes in order to unravel cell-signaling networks that occur from peripheral structures to olfactory cortical areas during odor processing.
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Affiliation(s)
- Mercedes Lachén-Montes
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Joaquín Fernández-Irigoyen
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,Proteomics Unit, Navarrabiomed, Proteored-ISCIII, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Enrique Santamaría
- Clinical Neuroproteomics Group, Navarrabiomed, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain.,Proteomics Unit, Navarrabiomed, Proteored-ISCIII, Instituto de investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
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5
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Affiliation(s)
- Anne Tromelin
- CNRS; UMR6265 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- INRA; UMR1324 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- Université de Bourgogne; UMR Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
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6
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Bao G, de Jong D, Alevra M, Schild D. Ca(2+)-BK channel clusters in olfactory receptor neurons and their role in odour coding. Eur J Neurosci 2015; 42:2985-95. [PMID: 26452167 DOI: 10.1111/ejn.13095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 09/17/2015] [Accepted: 10/03/2015] [Indexed: 11/26/2022]
Abstract
Olfactory receptor neurons (ORNs) have high-voltage-gated Ca(2+) channels whose physiological impact has remained enigmatic since the voltage-gated conductances in this cell type were first described in the 1980s. Here we show that in ORN somata of Xenopus laevis tadpoles these channels are clustered and co-expressed with large-conductance potassium (BK) channels. We found approximately five clusters per ORN and twelve Ca(2+) channels per cluster. The action potential-triggered activation of BK channels accelerates the repolarization of action potentials and shortens interspike intervals during odour responses. This increases the sensitivity of individual ORNs to odorants. At the level of mitral cells of the olfactory bulb, odour qualities have been shown to be coded by first-spike-latency patterns. The system of Ca(2+) and BK channels in ORNs appears to be important for correct odour coding because the blockage of BK channels not only affects ORN spiking patterns but also changes the latency pattern representation of odours in the olfactory bulb.
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Affiliation(s)
- Guobin Bao
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany
| | - Daniëlle de Jong
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany
| | - Mihai Alevra
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.,DFG Excellence Cluster 171, University of Göttingen, Göttingen, Germany
| | - Detlev Schild
- Institute of Neurophysiology and Cellular Biophysics, University of Göttingen, Humboldtallee 23, 37073, Göttingen, Germany.,DFG Research Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), University of Göttingen, Göttingen, Germany.,DFG Excellence Cluster 171, University of Göttingen, Göttingen, Germany
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7
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Whitlock KE. The loss of scents: do defects in olfactory sensory neuron development underlie human disease? ACTA ACUST UNITED AC 2015; 105:114-25. [PMID: 26111003 DOI: 10.1002/bdrc.21094] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/12/2015] [Indexed: 12/20/2022]
Abstract
The olfactory system is a fascinating and beguiling sensory system: olfactory sensory neurons detect odors underlying behaviors essential for mate choice, food selection, and escape from predators, among others. These sensory neurons are unique in that they have dendrites contacting the outside world, yet their first synapse lies in the central nervous system. The information entering the central nervous system is used to create odor memories that play a profound role in recognition of individuals, places, and appropriate foods. Here, the structure of the olfactory epithelium is given as an overview to discuss the origin of the olfactory placode, the plasticity of the olfactory sensory neurons, and finally the origins of the gonadotropin-releasing hormone neuroendocrine cells. For the purposes of this review, the development of the peripheral sensory system will be analyzed, incorporating recently published studies highlighting the potential novelties in development mechanisms. Specifically, an emerging model where the olfactory epithelium and olfactory bulb develop simultaneously from a continuous neurectoderm patterned at the end of gastrulation, and the multiple origins of the gonadotropin-releasing hormone neuroendocrine cells associated with the olfactory sensory system development will be presented. Advances in the understanding of the basic mechanisms underlying olfactory sensory system development allows for a more thorough understanding of the potential causes of human disease.
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Affiliation(s)
- Kathleen E Whitlock
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaiso, Valparaiso, Chile
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8
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Abstract
Cilia are highly conserved for their structure and also for their sensory functions. They serve as antennae for extracellular information. Whether the cilia are motile or not, they respond to environmental mechanical and chemical stimuli and signal to the cell body. The information from extracellular stimuli is commonly converted to electrical signals through the repertoire of ion-conducting channels in the ciliary membrane resulting in changes in concentrations of ions, especially Ca2+, in the cilia. These changes, in turn, affect motility and signaling pathways in the cilia and cell body to carry on the signal transduction. We review here the activities of ion channels in cilia from protists to vertebrates.
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Affiliation(s)
- Steven J Kleene
- Department of Molecular and Cellular Physiology University of Cincinnati Cincinnati, OH 45267-0576 USA 1-513-558-6099 (phone) 1-513-558-5738 (fax)
| | - Judith L Van Houten
- Department of Biology University of Vermont Burlington, VT 05405, USA 1-802-656-0452 (phone) 1-802-656-2914 (FAX)
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9
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Abstract
Primary cilia are microtubule-based organelles found on most types of cells in the human body. Although primary cilia were long thought to be vestigial remnants of motile cilia, it is now known that primary cilia play important roles in development and physiology, and defects of primary cilia cause a wide range of human disease symptoms, termed ciliopathies. To understand ciliary functions and the molecular mechanisms underlying ciliopathies, it is important to know the components of primary cilia, but primary cilia have proven to be more difficult to isolate than motile cilia. This chapter describes the isolation and imaging of mammalian primary cilia for biochemical and cell biological analyses.
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Affiliation(s)
- Hiroaki Ishikawa
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California, USA
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Osada K, Hanawa M, Tsunoda K, Izumi H. Evaluation of the Masking of Dimethyl Sulfide Odors by Citronellal, Limonene and Citral through the Use of Trained Odor Sensor Mice. Chem Senses 2012; 38:57-65. [DOI: 10.1093/chemse/bjs077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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11
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Valentine MS, Rajendran A, Yano J, Weeraratne SD, Beisson J, Cohen J, Koll F, Van Houten J. Paramecium BBS genes are key to presence of channels in Cilia. Cilia 2012; 1:16. [PMID: 23351336 PMCID: PMC3556005 DOI: 10.1186/2046-2530-1-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Accepted: 06/14/2012] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED BACKGROUND Changes in genes coding for ciliary proteins contribute to complex human syndromes called ciliopathies, such as Bardet-Biedl Syndrome (BBS). We used the model organism Paramecium to focus on ciliary ion channels that affect the beat form and sensory function of motile cilia and evaluate the effects of perturbing BBS proteins on these channels. METHODS We used immunoprecipitations and mass spectrometry to explore whether Paramecium proteins interact as in mammalian cells. We used RNA interference (RNAi) and swimming behavior assays to examine the effects of BBS depletion on ciliary ion channels that control ciliary beating. Combining RNA interference and epitope tagging, we examined the effects of BBS depletion of BBS 7, 8 and 9 on the location of three channels and a chemoreceptor in cilia. RESULTS We found 10 orthologs of 8 BBS genes in P. tetraurelia. BBS1, 2, 4, 5, 7, 8 and 9 co-immunoprecipitate. While RNAi reduction of BBS 7 and 9 gene products caused loss and shortening of cilia, RNAi for all BBS genes except BBS2 affected patterns of ciliary motility that are governed by ciliary ion channels. Swimming behavior assays pointed to loss of ciliary K+ channel function. Combining RNAi and epitope tagged ciliary proteins we demonstrated that a calcium activated K+ channel was no longer located in the cilia upon depletion of BBS 7, 8 or 9, consistent with the cells' swimming behavior. The TRPP channel PKD2 was also lost from the cilia. In contrast, the ciliary voltage gated calcium channel was unaffected by BBS depletion, consistent with behavioral assays. The ciliary location of a chemoreceptor for folate was similarly unperturbed by the depletion of BBS 7, 8 or 9. CONCLUSIONS The co-immunoprecipitation of BBS 1,2,4,5,7,8, and 9 suggests a complex of BBS proteins. RNAi for BBS 7, 8 or 9 gene products causes the selective loss of K+ and PKD2 channels from the cilia while the critical voltage gated calcium channel and a peripheral receptor protein remain undisturbed. These channels govern ciliary beating and sensory function. Importantly, in P. tetraurelia we can combine studies of ciliopathy protein function with behavior and location and control of ciliary channels.
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Affiliation(s)
- Megan Smith Valentine
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, VT, 05405, USA
| | - Anbazhagan Rajendran
- Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, 02215, USA
| | - Junji Yano
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, VT, 05405, USA
| | | | - Janine Beisson
- Center for Molecular Genetics, National Center for Scientific Research, Génétique Moléculaire, CNRS, Gif-sur-Yvette, 91198, France
- Université Paris-Sud, Orsay, 91405, France
| | - Jean Cohen
- Center for Molecular Genetics, National Center for Scientific Research, Génétique Moléculaire, CNRS, Gif-sur-Yvette, 91198, France
- Université Paris-Sud, Orsay, 91405, France
| | - France Koll
- Center for Molecular Genetics, National Center for Scientific Research, Génétique Moléculaire, CNRS, Gif-sur-Yvette, 91198, France
- Université Paris-Sud, Orsay, 91405, France
| | - Judith Van Houten
- Department of Biology, University of Vermont, 109 Carrigan Drive, Burlington, VT, 05405, USA
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12
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Ligeti E, Csépányi-Kömi R, Hunyady L. Physiological mechanisms of signal termination in biological systems. Acta Physiol (Oxf) 2012; 204:469-78. [PMID: 22260256 DOI: 10.1111/j.1748-1716.2012.02414.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 09/20/2011] [Accepted: 01/11/2012] [Indexed: 11/29/2022]
Abstract
Studies on the regulation of cellular activity mainly focus on signal generation, but termination of signalling is an equally important factor, which prevents inappropriate activity. This paper reviews the mechanisms, which can cause termination of signalling, and provides examples that illustrate the importance of these processes. Inactivation of voltage-gated Na(+) channels and the photoactivated rhodopsin molecule is caused by rapid conformational rearrangements. Negative feedback can also contribute to the termination of signalling for various mechanisms, including plasma membrane ion channels or cAMP signal generation. In immune cells, the tyrosine-based inhibitory motif (ITIM)-containing molecules are essential negative regulatory components. Desensitization of G-protein-coupled receptors can occur with homologous and heterologous mechanisms, mediated by β-arrestin molecules and second messenger-induced kinases respectively. In NF-κB signalling, resynthetized IκB and other enzymes form negative feedback loops. GTPase-activating proteins are also dedicated to termination of signalling, because they can switch off the small G proteins by increasing their endogenous GTP hydrolysis. In many systems, signal termination is a result of a combined action of several different mechanisms, which underlines the importance of these processes.
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Affiliation(s)
- E. Ligeti
- Faculty of Medicine; Department of Physiology; Semmelweis University; Budapest Hungary
| | - R. Csépányi-Kömi
- Faculty of Medicine; Department of Physiology; Semmelweis University; Budapest Hungary
| | - L. Hunyady
- Faculty of Medicine; Department of Physiology; Semmelweis University; Budapest Hungary
- Laboratory of Neurobiochemistry and Molecular Physiology; Semmelweis University and Hungarian Academy of Sciences; Budapest Hungary
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13
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Mitchell KAP, Szabo G, Otero ADS. Methods for the isolation of sensory and primary cilia--an overview. Methods Cell Biol 2009; 94:87-101. [PMID: 20362086 DOI: 10.1016/s0091-679x(08)94004-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Detailed proteomic analyses of mammalian olfactory and rod photoreceptor sensory cilia are now available, providing an inventory of resident ciliary proteins and laying the foundation for future studies of developmental and spatiotemporal changes in the composition of sensory cilia. Cilia purification methods that were elaborated and perfected over several decades were essential for these advances. In contrast, the proteome of primary cilia is yet to be established, because purification procedures for this organelle have been developed only recently. In this chapter, we review current techniques for the purification of olfactory and photoreceptor cilia, and evaluate methods designed for the selective isolation of primary cilia.
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Affiliation(s)
- Kimberly A P Mitchell
- Department of Biology and Chemistry, Liberty University, Lynchburg, Virginia 24502, USA
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14
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Abstract
Odour-mediated signal transduction is a complex process that occurs in the cilia of olfactory sensory neurons. To gain insight in to the molecular organization of the odour transduction machinery, we developed a procedure to purify olfactory cilia membranes by differential centrifugation of rat olfactory epithelium extracts. We tested whether known scaffolding proteins that might participate in the assembly of the complex chemotransduction apparatus are present in the purified membrane fraction. Utilizing immunoblotting and immunohistochemistry, we show that the multidomain scaffolding proteins ProSAP/Shanks and calcium/calmodulin-dependent serine protein kinase CASK are present in the olfactory cilia. Ion channels involved in chemotransduction could be reconstituted into planar lipid bilayers for electrophysiological recordings. Our procedure should allow the identification of further chemotransduction-related proteins.
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15
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Kleene SJ. The electrochemical basis of odor transduction in vertebrate olfactory cilia. Chem Senses 2008; 33:839-59. [PMID: 18703537 DOI: 10.1093/chemse/bjn048] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Most vertebrate olfactory receptor neurons share a common G-protein-coupled pathway for transducing the binding of odorant into depolarization. The depolarization involves 2 currents: an influx of cations (including Ca2+) through cyclic nucleotide-gated channels and a secondary efflux of Cl- through Ca2+-gated Cl- channels. The relation between stimulus strength and receptor current shows positive cooperativity that is attributed to the channel properties. This cooperativity amplifies the responses to sufficiently strong stimuli but reduces sensitivity and dynamic range. The odor response is transient, and prolonged or repeated stimulation causes adaptation and desensitization. At least 10 mechanisms may contribute to termination of the response; several of these result from an increase in intraciliary Ca2+. It is not known to what extent regulation of ionic concentrations in the cilium depends on the dendrite and soma. Although many of the major mechanisms have been identified, odor transduction is not well understood at a quantitative level.
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Affiliation(s)
- Steven J Kleene
- Department of Cancer and Cell Biology, University of Cincinnati, PO Box 670667, 231 Albert Sabin Way, Cincinnati, OH 45267-0667, USA.
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16
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Zhang P, Yang C, Delay RJ. Urine stimulation activates BK channels in mouse vomeronasal neurons. J Neurophysiol 2008; 100:1824-34. [PMID: 18701755 DOI: 10.1152/jn.90555.2008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Most odor responses in mouse vomeronasal neurons are mediated by the phospholipase C (PLC) pathway, activation of which elevates diacylglycerol (DAG). Lucas et al. showed that DAG activates transient receptor potential channels, subfamily C, member 2 (TRPC2), resulting in a depolarizing Ca2+ influx. DAG can be subsequently converted to arachidonic acid (AA) by a DAG lipase, the role of which remains largely unknown. In this study, we found that urine stimulation of vomeronasal neurons activated large-conductance Ca2+-activated K+ (BK) channels via AA production. Using isolated neurons, we demonstrated that repetitive applications of AA potentiated a K+ current that required a Ca2+ influx and was sensitive to specific BK blockers. Using immunocytochemistry, we found that BK channels are present in vomeronasal neurons with labeling on the soma and heavy labeling on the dendrite with a BK channel antibody. We examined the role of these BK channels in regulating neuronal firing when the neuron was activated by membrane depolarization or urine. Contrary to a recent report, our data suggest that BK channels contribute to adaptation of urine/odor responses because the inhibition of BK channels during urine stimulation promoted repetitive firing. These data strongly support the hypothesis that AA mediates an inhibitory pathway through BK channels, a possible mechanism for odor adaptation in vomeronasal neurons.
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Affiliation(s)
- Peng Zhang
- Department of Biology, University of Vermont, Burlington, VT 05405, USA
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Klimmeck D, Mayer U, Ungerer N, Warnken U, Schnölzer M, Frings S, Möhrlen F. Calcium-signaling networks in olfactory receptor neurons. Neuroscience 2007; 151:901-12. [PMID: 18155848 DOI: 10.1016/j.neuroscience.2007.11.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 10/31/2007] [Accepted: 11/16/2007] [Indexed: 01/03/2023]
Abstract
The olfactory neuroepithelium represents a unique interface between the brain and the external environment. Olfactory function comprises a distinct set of molecular tasks: sensory signal transduction, cytoprotection and adult neurogenesis. A multitude of biochemical studies has revealed the central role of Ca(2+) signaling in the function of olfactory receptor neurons (ORNs). We set out to establish Ca(2+)-dependent signaling networks in ORN cilia by proteomic analysis. We subjected a ciliary membrane preparation to Ca(2+)/calmodulin-affinity chromatography using mild detergent conditions in order to maintain functional protein complexes involved in olfactory Ca(2+) signaling. Thus, calmodulin serves as a valuable tool to gain access to novel Ca(2+)-regulated protein complexes. Tandem mass spectrometry (nanoscale liquid-chromatography-electrospray injection) identified 123 distinct proteins. Ninety-seven proteins (79%) could be assigned to specific olfactory functions, including 32 to sensory signal transduction and 40 to cytoprotection. We point out novel perspectives for research on the Ca(2+)-signaling networks in the olfactory system of the rat.
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Affiliation(s)
- D Klimmeck
- Department of Molecular Physiology, Institute of Zoology, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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18
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Castillo K, Delgado R, Bacigalupo J. Plasma membrane Ca(2+)-ATPase in the cilia of olfactory receptor neurons: possible role in Ca(2+) clearance. Eur J Neurosci 2007; 26:2524-31. [PMID: 17970729 DOI: 10.1111/j.1460-9568.2007.05863.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Olfactory sensory neurons respond to odorants increasing Ca(2+) concentrations in their chemosensory cilia. Calcium enters the cilia through cAMP-gated channels, activating Ca(2+)-dependent chloride or potassium channels. Calcium also has a fundamental role in odour adaptation, regulating cAMP turnover rate and the affinity of the cyclic nucleotide-gated channels for cAMP. It has been shown that a Na(+)/Ca(2+) exchanger (NCX) extrudes Ca(2+) from the cilia. Here we confirm previous evidence that olfactory cilia also express plasma membrane Ca(2+)-ATPase (PMCA), and show the first evidence supporting a role in Ca(2+) removal. Both transporters were detected by immunoblot of purified olfactory cilia membranes. The pump was also revealed by immunocytochemistry and immunohistochemistry. Inside-out cilia membrane vesicles transported Ca(2+) in an ATP-dependent fashion. PMCA activity was potentiated by luminal Ca(2+) (K(0.5) = 670 nm) and enhanced by calmodulin (CaM; K(0.5) = 31 nm). Both carboxyeosin (CE) and calmidazolium reduced Ca(2+) transport, as expected for a CaM-modulated PMCA. The relaxation time constant (tau) of the Ca(2+)-dependent Cl(-) current (272 +/- 78 ms), indicative of luminal Ca(2+) decline, was increased by CE (2181 +/- 437 ms), by omitting ATP (666 +/- 49 ms) and by raising pH (725 +/- 65 ms), suggesting a role of the pump on Ca(2+) clearance. Replacement of external Na(+) by Li(+) had a similar effect (tau = 442 +/- 8 ms), confirming the NCX involvement in Ca(2+) extrusion. The evidence suggests that both Ca(2+) transporters contribute to re-establish resting Ca(2+) levels in the cilia following olfactory responses.
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Affiliation(s)
- Karen Castillo
- Department of Biology, Faculty of Sciences and Millennium Institute for Cell Dynamics and Biotechnology, University of Chile, Santiago, Chile
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Ukhanov K, Leinders-Zufall T, Zufall F. Patch-clamp analysis of gene-targeted vomeronasal neurons expressing a defined V1r or V2r receptor: ionic mechanisms underlying persistent firing. J Neurophysiol 2007; 98:2357-69. [PMID: 17715188 DOI: 10.1152/jn.00642.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sensory neurons in the mouse vomeronasal organ consist of two major groups, apical and basal, that project to different brain regions, express unique sets of receptors, and serve distinct functions. Electrical properties of these two subpopulations, however, have not been systematically characterized. V1rb2-tau-GFP and V2r1b-tau-GFP tagged vomeronasal sensory neurons (VSNs) were selected as prototypical apical or basal VSNs, respectively, and their biophysical properties were analyzed in acute slices that minimized cell damage. Basal V2r1b-expressing VSNs had voltage-gated conductances, and especially Na(+) (Nav) and Ca(2+) (Cav) currents, that were substantially larger than those observed in apical V1rb2 VSNs, although the resting membrane potential, input resistance, and membrane capacitance were similar in both cell types. Of several types of Cav currents, T-type and L-type Cav currents contributed to action potential firing, and both currents alone were capable of generating oscillatory Ca(2+) spikes. The L-type Cav current was uniquely coupled to a BK large-conductance K(+) current, and interplay between these channels played a critical role in repolarizing spikes and maintaining persistent firing in VSNs. Larger Nav and Cav conductances, along with a more positive inactivation voltage of the Nav current in the V2r1b VSNs, contributed to the larger spike amplitude and higher spike frequency induced by depolarizing current in these cells compared with V1rb2 VSNs. Basal GFP-negative VSNs and V2r1b VSNs responded to prolonged depolarization with persistent, but adapting discharge that could be relevant in sensory adaptation. Collectively, these results suggest a novel mechanism for regulating and encoding neuronal activity in the accessory olfactory system.
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Affiliation(s)
- Kirill Ukhanov
- Whitney Laboratory for Marine Bioscience, Center for Smell and Taste, and the McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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Chen TY, Takeuchi H, Kurahashi T. Odorant inhibition of the olfactory cyclic nucleotide-gated channel with a native molecular assembly. ACTA ACUST UNITED AC 2006; 128:365-71. [PMID: 16940558 PMCID: PMC2151561 DOI: 10.1085/jgp.200609577] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human olfaction comprises the opposing actions of excitation and inhibition triggered by odorant molecules. In olfactory receptor neurons, odorant molecules not only trigger a G-protein–coupled signaling cascade but also generate various mechanisms to fine tune the odorant-induced current, including a low-selective odorant inhibition of the olfactory signal. This wide-range olfactory inhibition has been suggested to be at the level of ion channels, but definitive evidence is not available. Here, we report that the cyclic nucleotide-gated (CNG) cation channel, which is a key element that converts odorant stimuli into electrical signals, is inhibited by structurally unrelated odorants, consistent with the expression of wide-range olfactory inhibition. Interestingly, the inhibitory effect was small in the homo-oligomeric CNG channel composed only of the principal channel subunit, CNGA2, but became larger in channels consisting of multiple types of subunits. However, even in the channel containing all native subunits, the potency of the suppression on the cloned CNG channel appeared to be smaller than that previously shown in native olfactory neurons. Nonetheless, our results further showed that odorant suppressions are small in native neurons if the subsequent molecular steps mediated by Ca2+ are removed. Thus, the present work also suggests that CNG channels switch on and off the olfactory signaling pathway, and that the on and off signals may both be amplified by the subsequent olfactory signaling steps.
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Affiliation(s)
- Tsung-Yu Chen
- Center for Neuroscience and Department of Neurology, University of California, Davis, CA 95616, USA.
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Gautam SH, Otsuguro KI, Ito S, Saito T, Habara Y. T-type Ca2+ channels contribute to IBMX/forskolin- and K(+)-induced Ca(2+) transients in porcine olfactory receptor neurons. Neurosci Res 2006; 57:129-39. [PMID: 17074407 DOI: 10.1016/j.neures.2006.09.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 09/15/2006] [Accepted: 09/25/2006] [Indexed: 01/08/2023]
Abstract
T-type Ca(2+) channels are low-voltage-activated Ca(2+) channels that control Ca(2+) entry in excitable cells during small depolarization above resting potentials. Using Ca(2+) imaging with a laser scanning confocal microscope we investigated the involvement of T-type Ca(2+) channels in IBMX/forskolin- and sparingly elevated extracellular K(+)-induced Ca(2+) transients in freshly isolated porcine olfactory receptor neurons (ORNs). In the presence of mibefradil (10microM) or Ni(2+) (100microM), the selective T-type Ca(2+) channel inhibitors, IBMX/forskolin-induced Ca(2+) transients in the soma were either strongly (>60%) inhibited or abolished completely. However, the Ca(2+) transients in the knob were only partially (<60%) inhibited. Ca(2+) transients induced by 30mM K(+) were also partially ( approximately 60%) inhibited at both the knob and soma. Furthermore, ORNs responded to as little as a 2.5mM increase in the extracellular K(+) concentration (7.5mM K(+)), and such responses were completely inhibited by mibefradil or Ni(2+). These results reveal functional expression of T-type Ca(2+) channels in porcine ORNs, and suggest a role for these channels in the spread Ca(2+) transients from the knob to the soma during activation of the cAMP cascade following odorant binding to G-protein-coupled receptors on the cilia/knob of ORNs.
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Affiliation(s)
- Shree Hari Gautam
- Laboratory of Physiology, Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
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Raychowdhury MK, McLaughlin M, Ramos AJ, Montalbetti N, Bouley R, Ausiello DA, Cantiello HF. Characterization of single channel currents from primary cilia of renal epithelial cells. J Biol Chem 2005; 280:34718-22. [PMID: 16079132 DOI: 10.1074/jbc.m507793200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The primary cilium is a ubiquitous, non-motile microtubular organelle lacking the central pair of microtubules found in motile cilia. Primary cilia are surrounded by a membrane, which has a unique complement of membrane proteins, and may thus be functionally different from the plasma membrane. The function of the primary cilium remains largely unknown. However, primary cilia have important sensory transducer properties, including the response of renal epithelial cells to fluid flow or mechanical stimulation. Recently, renal cystic diseases have been associated with dysfunctional ciliary proteins. Although the sensory properties of renal epithelial primary cilia may be associated with functional channel activity in the organelle, information in this regard is still lacking. This may be related to the inherent difficulties in assessing electrical activity in this rather small and narrow organelle. In the present study, we provide the first direct electrophysiological evidence for the presence of single channel currents from isolated primary cilia of LLC-PK1 renal epithelial cells. Several channel phenotypes were observed, and addition of vasopressin increased cation channel activity, which suggests the regulation, by the cAMP pathway of ciliary conductance. Ion channel reconstitution of ciliary versus plasma membranes indicated a much higher channel density in cilia. At least three channel proteins, polycystin-2, TRPC1, and interestingly, the alpha-epithelial sodium channel, were immunodetected in this organelle. Ion channel activity in the primary cilium of renal cells may be an important component of its role as a sensory transducer.
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Affiliation(s)
- Malay K Raychowdhury
- Renal Unit, Massachusetts General Hospital East, Charlestown, Massachusetts 02129, USA
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Castillo K, Bacigalupo J, Wolff D. Ca2+-dependent K+ channels from rat olfactory cilia characterized in planar lipid bilayers. FEBS Lett 2005; 579:1675-82. [PMID: 15757660 DOI: 10.1016/j.febslet.2005.01.079] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Revised: 01/26/2005] [Accepted: 01/28/2005] [Indexed: 11/22/2022]
Abstract
Olfactory cilia contain cyclic nucleotide-gated and Ca2+-dependent Cl- conductances that underlie excitatory chemotransduction, and a Ca2+-dependent K+ (KCa) conductance, apparently involved in inhibitory transduction. Previous single-channel patch-clamp studies on olfactory cilia revealed four different KCas, with different conductances and kinetics. Here, we further characterized these channels in planar bilayers, where blockers could be properly tested. All four ciliary KCas were observed: The 16 pS channel, K0.5,Ca=40 microM and apamin-sensitive; the 30 and 50 pS channel, K0.5,Ca=59 microM, clotrimazole-sensitive and charybdotoxin-insensitive; the 60 pS channel, clotrimazole-sensitive and charybdotoxin-insensitive; and the 210 pS channel, K0.5,Ca=63 microM, blocked by charybdotoxin and iberiotoxin. The presence of the 16 and 210 pS channels was confirmed by immunoblotting.
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Affiliation(s)
- Karen Castillo
- Department of Biology, Faculty of Sciences, University of Chile, PO Box 653, Santiago, Chile
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Madrid R, Delgado R, Bacigalupo J. Cyclic AMP cascade mediates the inhibitory odor response of isolated toad olfactory receptor neurons. J Neurophysiol 2005; 94:1781-8. [PMID: 15817646 DOI: 10.1152/jn.01253.2004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Odor stimulation may excite or inhibit olfactory receptor neurons (ORNs). It is well established that the excitatory response involves a cyclic AMP (cAMP) transduction mechanism that activates a nonselective cationic cyclic nucleotide-gated (CNG) conductance, accompanied by the activation of a Ca2+-dependent Cl(-) conductance, both causing a depolarizing receptor potential. In contrast, odor inhibition is attributed to a hyperpolarizing receptor potential. It has been proposed that a Ca2+-dependent K+ (K(Ca)) conductance plays a key role in odor inhibition, both in toad and rat isolated olfactory neurons. The mechanism underlying odor inhibition has remained elusive. We assessed its study using various pharmacological agents and caged compounds for cAMP, Ca2+, and inositol 1,4,5-triphosphate (InsP3) on isolated toad ORNs. The odor-triggered K(Ca) current was reduced on exposing the cell either to the CNG channel blocker LY83583 (20 microM) or to the adenylyl cyclase inhibitor SQ22536 (100 microM). Photorelease of caged Ca2+ activated a Cl- current sensitive to niflumic acid (10 microM) and a K+ current blockable by charybdotoxin (20 nM) and iberiotoxin (20 nM). In contrast, photoreleased Ca2+ had no effect on cells missing their cilia, indicating that these conductances are confined to the cilia. Photorelease of cAMP induced a charybdotoxin-sensitive K+ current in intact ORNs. Photorelease of InsP3 did not increase the membrane conductance of olfactory neurons, arguing against a direct role of InsP3 in chemotransduction. We conclude that a cAMP cascade mediates the activation of the ciliary Ca2+-dependent K+ current and that the Ca2+ ions that activate the inhibitory current enter the cilia through CNG channels.
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Affiliation(s)
- Rodolfo Madrid
- Department of Biology, Faculty of Sciences, University of Chile, P.O. Box 653, Santiago, Chile
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Delgado R, Bacigalupo J. Cilium-attached and excised patch-clamp recordings of odourant-activated Ca-dependent K channels from chemosensory cilia of olfactory receptor neurons. Eur J Neurosci 2005; 20:2975-80. [PMID: 15579151 DOI: 10.1111/j.1460-9568.2004.03778.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
It has previously been proposed that a Ca2+-dependent K+ conductance is implicated in the inhibitory odourant response in rat and toad olfactory receptor neurons. Previous whole-cell and single-channel measurements on inside-out excised patches, in addition to immunochemical evidence, indicated the presence of Ca2+-dependent K+ channels in olfactory cilia, the transducing structures of these sensory cells. Ca2+-dependent K+ channels opened in 'on-cilium' membrane patches from C. caudiverbera upon odourant stimulation. Furthermore, after excision in the inside-out configuration, the channel could be opened by micromolar Ca2+, in a Ca2+-dependent fashion, but it was unresponsive to cyclic AMP. We estimated that the Ca2+ concentration in the proximity of a Ca2+-dependent K+ channel within the cilia reaches at least 100 microM during the odour response. The K+ channel displayed a higher selectivity for K+ than for Na+. Our results support a role for this Ca2+-dependent K+ channel in chemotransduction.
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Affiliation(s)
- Ricardo Delgado
- Millennium Institute for Advanced Studies in Cell Biology and Biotechnology, University of Chile, PO Box 653, Santiago, Chile
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Schmachtenberg O, Bacigalupo J. Olfactory transduction in ciliated receptor neurons of the Cabinza grunt, Isacia conceptionis (Teleostei: Haemulidae). Eur J Neurosci 2005; 20:3378-86. [PMID: 15610170 DOI: 10.1111/j.1460-9568.2004.03825.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ciliated receptor neurons of fish olfactory organs are thought to transduce amino acids through a cAMP-dependent transduction pathway, but direct physiological evidence for this hypothesis remains scarce and is confined to catfish and trout. We investigated olfactory transduction in a marine fish, the Cabinza grunt Isacia conceptionis (Perciformes, Teleostei). The olfactory epithelium was characterized using light and electron microscopy, and isolated ciliated receptor neurons were recorded with the perforated patch-clamp technique. Cells were stimulated with puffer pipettes containing amino acid odourants, IBMX plus forskolin or 8 bromo-cAMP. All three stimuli triggered transient inward currents at a holding potential of -70 mV and responses with outward-rectifying current-voltage relationships. The characteristics of the transduction currents induced by each stimulus were similar across cells and indistinguishable within the same cell, supporting the hypothesis of a cAMP pathway mediating transduction of amino acids in ciliated olfactory receptor neurons.
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Affiliation(s)
- Oliver Schmachtenberg
- Centro de Neurociencias de Valparaiso, Facultad de Ciencias, Universidad de Valparaiso, Avda. Gran Bretania 1111, Playa Ancha, Valparaiso, Chile.
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