1
|
Kwon JW, Jeon YK, Kim SJ. Bidirectional sensitivity of CALHM1 channel to protons from both sides of plasma membrane. Am J Physiol Cell Physiol 2023; 324:C98-C112. [PMID: 36409172 DOI: 10.1152/ajpcell.00250.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Calcium homeostasis modulator 1 (CALHM1), a newly discovered voltage-dependent nonselective ion channel, has drawn attention for its role in neuronal activity and taste sensation. Its sluggish voltage-dependent activation is facilitated by lowering extracellular Ca2+ concentration ([Ca2+]e). Here, we investigated the effects of extracellular and intracellular pH (pHe and pHi) on human CALHM1. When normalized to the amplitude of the CALHM1 current (ICALHM1) under whole cell patch clamp at symmetrical pH 7.4, ICALHM1 decreased at acidic pHe or pHi, whereas it sharply increased at alkaline pHe or pHi. The effects of pH were preserved in the inside-out configuration. The voltage dependence of ICALHM1 showed leftward and rightward shifts at alkaline and acidic pHe and pHi, respectively. Site-directed mutagenesis of the water-accessible charged residues of the pore and nearby domains revealed that E17, K229, E233, D257, and E259 are nonadditively responsible for facilitation at alkaline pHi. Identification of the pHe-sensing residue was not possible because mutation of putative residues impaired membrane expression, resulting in undetectable ICALHM1. Alkaline pHe-dependent facilitation appeared gradually with depolarization, suggesting that the sensitivity to pHe might be due to H+ diffusion through the open-state CALHM1. At pHe 6.2, decreased [Ca2+]e could not recover the inhibited ICALHM1 but further augmented the increased ICALHM1 at pHe 8.6, suggesting that unidentified common residues might contribute to the [Ca2+]e and acidic pHe. This study is the first, to our knowledge, to demonstrate the remarkable pH sensitivity of CALHM1, which might contribute to the pH-dependent modulation of neuronal excitability or taste sensation.
Collapse
Affiliation(s)
- Jae Won Kwon
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Young Keul Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| |
Collapse
|
2
|
Ren Y, Li Y, Wang Y, Wen T, Lu X, Chang S, Zhang X, Shen Y, Yang X. Cryo-EM structure of the heptameric calcium homeostasis modulator 1 channel. J Biol Chem 2022; 298:101838. [PMID: 35339491 PMCID: PMC9035704 DOI: 10.1016/j.jbc.2022.101838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 12/01/2022] Open
Abstract
Calcium homeostasis modulator 1 (CALHM1) is a voltage- and Ca2+-gated ATP channel that plays an important role in neuronal signaling. However, as the previously reported CALHM structures are all in the ATP-conducting state, the gating mechanism of ATP permeation is still elusive. Here, we report cryo-EM reconstructions of two Danio rerio CALHM1 heptamers with ordered or flexible long C-terminal helices at resolutions of 3.2 Å and 2.9 Å, respectively, and one D. rerio CALHM1 octamer with flexible long C-terminal helices at a resolution of 3.5 Å. Structural analysis shows that the heptameric CALHM1s are in an ATP-nonconducting state with a central pore diameter of approximately 6.6 Å. Compared with those inside the octameric CALHM1, the N-helix inside the heptameric CALHM1 is in the “down” position to avoid steric clashing with the adjacent TM1 helix. Molecular dynamics simulations show that as the N-helix moves from the “down” position to the “up” position, the pore size of ATP molecule permeation increases significantly. Our results provide important information for elucidating the mechanism of ATP molecule permeation in the CALHM1 channel.
Collapse
Affiliation(s)
- Yue Ren
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Yang Li
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Yaojie Wang
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Tianlei Wen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Xuhang Lu
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Shenghai Chang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, China
| | - Xing Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Center of Cryo Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuequan Shen
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China; Synergetic Innovation Center of Chemical Science and Engineering, 94 Weijin Road, Tianjin 300071, China.
| | - Xue Yang
- State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
| |
Collapse
|
3
|
Kwon JW, Jeon YK, Kim J, Kim SJ, Kim SJ. Intramolecular Disulfide Bonds for Biogenesis of CALHM1 Ion Channel Are Dispensable for Voltage-Dependent Activation. Mol Cells 2021; 44:758-769. [PMID: 34711692 PMCID: PMC8560582 DOI: 10.14348/molcells.2021.0131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/19/2021] [Accepted: 09/06/2021] [Indexed: 11/27/2022] Open
Abstract
Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (ICALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as ICALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect ICALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both ICALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.
Collapse
Affiliation(s)
- Jae Won Kwon
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Young Keul Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jinsung Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 03080, Korea
| |
Collapse
|
4
|
Abstract
Taste buds consist of specialized epithelial cells which detect particular tastants and synapse onto the afferent taste nerve innervating the endorgan. The nature of the neurotransmitter released by taste cells onto the nerve fiber was enigmatic early in this century although neurotransmitters for other sensory receptor cell types, e.g. hair cells, photoreceptors, was known for at least a decade. A 1999 paper by Burnstock and co-workers (Bo et al., 1999) showing the presence of P2X receptors on the afferent nerves served as a springboard for research that ultimately led to the discovery of ATP as the crucial neurotransmitter in the taste system (Finger et al., 2005). Subsequent work showed that a subpopulation of taste cells utilize a unique release channel, CALHM1/3, to release ATP in a voltage-dependent manner. Despite these advances, several aspects of purinergic transmission in this system remain to be elucidated.
Collapse
Affiliation(s)
- T Finger
- Dept. Cell & Developmental Biology, Dept. Otolaryngology, Univ. Colorado School of Medicine, Anschutz Medical Campus, MS 8108, Room L18-11118, RC-1, 12801 E. 17th Ave., Aurora, CO 80045, United States of America.
| | - Sue Kinnamon
- Dept. Cell & Developmental Biology, Dept. Otolaryngology, Univ. Colorado School of Medicine, Anschutz Medical Campus, MS 8108, Room L18-11118, RC-1, 12801 E. 17th Ave., Aurora, CO 80045, United States of America
| |
Collapse
|
5
|
Abstract
Detection of NaCl by the gustatory system is fundamental for salt intake and tissue homeostasis. Yet, signal transduction mechanisms for salty taste have remained obscure. In this issue of Neuron, Nomura et al. (2020) report that the epithelial sodium channel ENaC, which serves as the salty receptor, is co-expressed with the voltage-activated ATP release channel CALHM1/3 in a subset of taste cells and that these cells mediate amiloride-sensitive salty taste.
Collapse
Affiliation(s)
- Emily R Liman
- Department of Biological Sciences, Section of Neurobiology, University of Southern California, 3641 Watt Way, Los Angeles, CA 90089, USA.
| |
Collapse
|
6
|
Garrosa J, Paredes I, Marambaud P, López MG, Cano-Abad MF. Molecular and Pharmacological Modulation of CALHM1 Promote Neuroprotection against Oxygen and Glucose Deprivation in a Model of Hippocampal Slices. Cells 2020; 9:E664. [PMID: 32182953 DOI: 10.3390/cells9030664] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/04/2020] [Accepted: 03/04/2020] [Indexed: 12/11/2022] Open
Abstract
Calcium homeostasis modulator 1 (CALHM1) is a calcium channel involved in the regulation of cytosolic Ca2+ levels. From a physiological point of view, the open state of CALHM1 depends not only on voltage but also on the extracellular concentration of calcium ([Ca2+]) ions. At low [Ca2+]e or depolarization, the channel is opened, allowing Ca2+ influx; however, high extracellular [Ca2+]e or hyperpolarization promote its resting state. The unique Ca2+ permeation of CALHM1 relates to the molecular events that take place in brain ischemia, such as depolarization and extracellular changes in [Ca2+]e, particularly during the reperfusion phase after the ischemic insult. In this study, we attempted to understand its role in an in vitro model of ischemia, namely oxygen and glucose deprivation, followed by reoxygenation (OGD/Reox). To this end, hippocampal slices from wild-type Calhm1+/+, Calhm1+/−, and Calhm1−/− mice were subjected to OGD/Reox. Our results point out to a neuroprotective effect when CALHM1 is partially or totally absent. Pharmacological manipulation of CALHM1 with CGP37157 reduced cell death in Calhm1+/+ slices but not in that of Calhm1−/− mice after exposure to the OGD/Reox protocol. This ionic protection was also verified by measuring reactive oxygen species production upon OGD/Reox in Calhm1+/+ and Calhm1−/− mice, resulting in a downregulation of ROS production in Calhm1−/− hippocampal slices and increased expression of HIF-1α. Taken together, we can conclude that genetic or pharmacological inhibition of CALHM1 results in a neuroprotective effect against ischemia, due to an attenuation of the neuronal calcium overload and downregulation of oxygen reactive species production.
Collapse
|
7
|
de Freitas PHM, da Silva Ferreira NC, Fioravante-Rezende JG, de Menezes Santos L, Alves LA, Rozental R. Dispelling myths about connexins, pannexins and P2X7 in hypoxic-ischemic central nervous system. Neurosci Lett 2019; 695:76-85. [PMID: 29195910 DOI: 10.1016/j.neulet.2017.11.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 10/07/2017] [Accepted: 11/21/2017] [Indexed: 01/17/2023]
Abstract
In membrane physiology, as in other fields, myths or speculations may be repeated so often and so widely that they are perceived as facts. To some extent, this has occurred with regard to gap junctions, hemichannels, pannexin channels and P2X7 (ionotropic receptors), especially concerning the interpretation of the individual role of these channels in hypoxic-ischemic CNS since these channels may be closed by the same pharmacological blockers. Significance of existing controversial data are highlighted and contradictory views from different groups are critically discussed herein.
Collapse
|
8
|
Subramaniam S, Ozdener MH, Abdoul-Azize S, Saito K, Malik B, Maquart G, Hashimoto T, Marambaud P, Aribi M, Tordoff MG, Besnard P, Khan NA. ERK1/2 activation in human taste bud cells regulates fatty acid signaling and gustatory perception of fat in mice and humans. FASEB J 2016; 30:3489-3500. [PMID: 27358389 PMCID: PMC5024696 DOI: 10.1096/fj.201600422r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/21/2016] [Indexed: 12/12/2022]
Abstract
Obesity is a major public health problem. An in-depth knowledge of the molecular mechanisms of oro-sensory detection of dietary lipids may help fight it. Humans and rodents can detect fatty acids via lipido-receptors, such as CD36 and GPR120. We studied the implication of the MAPK pathways, in particular, ERK1/2, in the gustatory detection of fatty acids. Linoleic acid, a dietary fatty acid, induced via CD36 the phosphorylation of MEK1/2-ERK1/2-ETS-like transcription factor-1 cascade, which requires Fyn-Src kinase and lipid rafts in human taste bud cells (TBCs). ERK1/2 cascade was activated by Ca2+ signaling via opening of the calcium-homeostasis modulator-1 (CALHM1) channel. Furthermore, fatty acid-evoked Ca2+ signaling and ERK1/2 phosphorylation were decreased in both human TBCs after small interfering RNA knockdown of CALHM1 channel and in TBCs from Calhm1-/- mice. Targeted knockdown of ERK1/2 by small interfering RNA or PD0325901 (MEK1/2 inhibitor) in the tongue and genetic ablation of Erk1 or Calhm1 genes impaired preference for dietary fat in mice. Lingual inhibition of ERK1/2 in healthy volunteers also decreased orogustatory sensitivity for linoleic acid. Our data demonstrate that ERK1/2-MAPK cascade is regulated by the opening of CALHM1 Ca2+ channel in TBCs to modulate orogustatory detection of dietary lipids in mice and humans.-Subramaniam, S., Ozdener, M. H., Abdoul-Azize, S., Saito, K., Malik, B., Maquart, G., Hashimoto, T., Marambaud, P., Aribi, M., Tordoff, M. G., Besnard, P., Khan, N. A. ERK1/2 activation in human taste bud cells regulates fatty acid signaling and gustatory perception of fat in mice and humans.
Collapse
Affiliation(s)
| | | | | | | | - Bilal Malik
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Guillaume Maquart
- Unité Mixte de Recherche U866, INSERM, Université de Bourgogne, AgroSup, Dijon, France
| | | | - Philippe Marambaud
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, New York, USA
| | - Mourad Aribi
- Laboratory of Applied Molecular Biology and Immunology, Abou Bekr Bel-Kaid University, Tlemcen, Algeria
| | | | - Philippe Besnard
- Unité Mixte de Recherche U866, INSERM, Université de Bourgogne, AgroSup, Dijon, France
| | - Naim Akhtar Khan
- Unité Mixte de Recherche U866, INSERM, Université de Bourgogne, AgroSup, Dijon, France;
| |
Collapse
|
9
|
Agostini M, Fasolato C. When, where and how? Focus on neuronal calcium dysfunctions in Alzheimer's Disease. Cell Calcium 2016; 60:289-298. [PMID: 27451385 DOI: 10.1016/j.ceca.2016.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD), since its characterization as a precise form of dementia with its own pathological hallmarks, has captured scientists' attention because of its complexity. The last 30 years have been filled with discoveries regarding the elusive aetiology of this disease and, thanks to advances in molecular biology and live imaging techniques, we now know that an important role is played by calcium (Ca2+). Ca2+, as ubiquitous second messenger, regulates a vast variety of cellular processes, from neuronal excitation and communication, to muscle fibre contraction and hormone secretion, with its action spanning a temporal scale that goes from microseconds to hours. It is therefore very challenging to conceive a single hypothesis that can integrate the numerous findings on this issue with those coming from the classical fields of AD research such as amyloid-beta (Aβ) and tau pathology. In this contribution, we will focus our attention on the Ca2+ hypothesis of AD, dissecting it, as much as possible, in its subcellular localization, where the Ca2+ signal meets its specificity. We will also follow the temporal evolution of the Ca2+ hypothesis, providing some of the most updated discoveries. Whenever possible, we will link the findings regarding Ca2+ dysfunction to the other players involved in AD pathogenesis, hoping to provide a crossover body of evidence, useful to amplify the knowledge that will lead towards the discovery of an effective therapy.
Collapse
Affiliation(s)
- Mario Agostini
- Department of Biomedical Sciences, University of Padua, Italy.
| | | |
Collapse
|
10
|
Liu W, Ao Q, Guo Q, He W, Peng L, Jiang J, Hu X. miR-9 Mediates CALHM1-Activated ATP-P2X7R Signal in Painful Diabetic Neuropathy Rats. Mol Neurobiol 2016; 54:922-929. [PMID: 26781424 DOI: 10.1007/s12035-016-9700-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 01/05/2016] [Indexed: 12/20/2022]
Abstract
In this study, we planned to illuminate the mechanisms of the expression and function of CALHM1 in painful diabetic neuropathy (PDN). PDN rat model was constructed. The expression of CALHM1 and miR-9 in rat spinal dorsal horn neurons was detected. The correlation between the level of CALHM1 mRNA and 50 % PWT and the relationship between the expression of CALHM1 and miR-9 in rat spinal dorsal horn neurons were statistically analyzed. The effect of miR-9 and CALHM1 on each other's expression in PDN rat spinal dorsal horn neurons were tested by qRT-PCR or Western blot. The co-culture system of neurons and glias from PDN rat spinal dorsal horn was constructed. The concentration of calcium and ATP as well as the expression of P2X7 receptor regulated by CALHM1 and miR-9 in PDN rat spinal dorsal horn neurons was measured. The results showed that the expression of CALHM1 was increased in PDN rat compared with controls, while its mRNA level was negatively correlated with 50 % PWT. miR-9, which was also upregulated in the spinal dorsal horn neurons of PDN rats, was positively correlated with the expression of CALHM1. The concentration of calcium and ATP as well as the expression of P2X7 receptor in glias was also increased in PDN rats. These increases could be reverted by inhibiting CALHM1 and/or miR-9. CALHM1 is involved in miR-9-mediated ATP-P2X7 pathway between neurons and glias in PDN rat.
Collapse
Affiliation(s)
- Wenjie Liu
- Anesthesia Department, The First Affiliated Hospital of Nanhua University, Chuanshan Road 69, Hengyang, 421001, Hunan, China
| | - Qinying Ao
- Health School, The Affiliated Nanhua Hospital of Nanhua University, Dongfeng South Road 336, Hengyang, 421001, Hunan, China
| | - Qulian Guo
- Anesthesia Department, Xiangya Hospital of Central South University, Xiangya Road 87, Changsha, 410008, Hunan, China
| | - Wanyou He
- Anesthesia Department, The First People's Hospital of Foshan City, Lingnan Avenue North 81, Foshan, 528000, Guangdong, China
| | - Liangyu Peng
- Anesthesia Department, The First Affiliated Hospital of Nanhua University, Chuanshan Road 69, Hengyang, 421001, Hunan, China
| | - Jun Jiang
- Anesthesia Department, The First Affiliated Hospital of Nanhua University, Chuanshan Road 69, Hengyang, 421001, Hunan, China
| | - Xiaoling Hu
- Anesthesia Department, The First Affiliated Hospital of Nanhua University, Chuanshan Road 69, Hengyang, 421001, Hunan, China.
| |
Collapse
|
11
|
Vingtdeux V, Chandakkar P, Zhao H, Blanc L, Ruiz S, Marambaud P. CALHM1 ion channel elicits amyloid-β clearance by insulin-degrading enzyme in cell lines and in vivo in the mouse brain. J Cell Sci 2015; 128:2330-8. [PMID: 25999473 DOI: 10.1242/jcs.167270] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/18/2015] [Indexed: 01/21/2023] Open
Abstract
Alzheimer's disease is characterized by amyloid-β (Aβ) peptide accumulation in the brain. CALHM1, a cell-surface Ca(2+) channel expressed in brain neurons, has anti-amyloidogenic properties in cell cultures. Here, we show that CALHM1 controls Aβ levels in vivo in the mouse brain through a previously unrecognized mechanism of regulation of Aβ clearance. Using pharmacological and genetic approaches in cell lines, we found that CALHM1 ion permeability and extracellular Ca(2+) were required for the Aβ-lowering effect of CALHM1. Aβ level reduction by CALHM1 could be explained by an increase in extracellular Aβ degradation by insulin-degrading enzyme (IDE), extracellular secretion of which was strongly potentiated by CALHM1 activation. Importantly, Calhm1 knockout in mice reduced IDE enzymatic activity in the brain, and increased endogenous Aβ concentrations by up to ∼50% in both the whole brain and primary neurons. Thus, CALHM1 controls Aβ levels in cell lines and in vivo by facilitating neuronal and Ca(2+)-dependent degradation of extracellular Aβ by IDE. This work identifies CALHM1 ion channel as a potential target for promoting amyloid clearance in Alzheimer's disease.
Collapse
Affiliation(s)
- Valérie Vingtdeux
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Manhasset, New York 11030 USA The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| | - Pallavi Chandakkar
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Manhasset, New York 11030 USA The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| | - Haitian Zhao
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Manhasset, New York 11030 USA The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| | - Lionel Blanc
- The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| | - Santiago Ruiz
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Manhasset, New York 11030 USA The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| | - Philippe Marambaud
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, Manhasset, New York 11030 USA The Feinstein Institute for Medical Research, Manhasset, New York 11030 USA
| |
Collapse
|
12
|
Tordoff MG, Aleman TR, Ellis HT, Ohmoto M, Matsumoto I, Shestopalov VI, Mitchell CH, Foskett JK, Poole RL. Normal Taste Acceptance and Preference of PANX1 Knockout Mice. Chem Senses 2015; 40:453-9. [PMID: 25987548 DOI: 10.1093/chemse/bjv025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Taste compounds detected by G protein-coupled receptors on the apical surface of Type 2 taste cells initiate an intracellular molecular cascade culminating in the release of ATP. It has been suggested that this ATP release is accomplished by pannexin 1 (PANX1). However, we report here that PANX1 knockout mice do not differ from wild-type controls in response to representative taste solutions, measured using 5-s brief-access tests or 48-h two-bottle choice tests. This implies that PANX1 is unnecessary for taste detection and consequently that ATP release from Type 2 taste cells does not require PANX1.
Collapse
Affiliation(s)
- Michael G Tordoff
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA,
| | - Tiffany R Aleman
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Hillary T Ellis
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Makoto Ohmoto
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Ichiro Matsumoto
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| | - Val I Shestopalov
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, FL 33136, USA
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, 240 South 40th Street, PA 19104, USA, and
| | - J Kevin Foskett
- Department of Physiology, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
| | - Rachel L Poole
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
| |
Collapse
|
13
|
Hellekant G, Schmolling J, Marambaud P, Rose-Hellekant TA. CALHM1 Deletion in Mice Affects Glossopharyngeal Taste Responses, Food Intake, Body Weight, and Life Span. Chem Senses 2015; 40:373-9. [PMID: 25855639 DOI: 10.1093/chemse/bjv009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Stimulation of Type II taste receptor cells (TRCs) with T1R taste receptors causes sweet or umami taste, whereas T2Rs elicit bitter taste. Type II TRCs contain the calcium channel, calcium homeostasis modulator protein 1 (CALHM1), which releases adenosine triphosphate (ATP) transmitter to taste fibers. We have previously demonstrated with chorda tympani nerve recordings and two-bottle preference (TBP) tests that mice with genetically deleted Calhm1 (knockout [KO]) have severely impaired perception of sweet, bitter, and umami compounds, whereas their sour and salty tasting ability is unaltered. Here, we present data from KO mice of effects on glossopharyngeal (NG) nerve responses, TBP, food intake, body weight, and life span. KO mice have no NG response to sweet and a suppressed response to bitter compared with control (wild-type [WT]) mice. KO mice showed some NG response to umami, suggesting that umami taste involves both CALHM1- and non-CALHM1-modulated signals. NG responses to sour and salty were not significantly different between KO and WT mice. Behavioral data conformed in general with the NG data. Adult KO mice consumed less food, weighed significantly less, and lived almost a year longer than WT mice. Taken together, these data demonstrate that sweet taste majorly influences food intake, body weight, and life span.
Collapse
Affiliation(s)
- Göran Hellekant
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
| | - Jared Schmolling
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
| | - Philippe Marambaud
- Litwin-Zucker Research Center for the Study of Alzheimer's Disease, The Feinstein Institute for Medical Research, Manhasset, NY 11030, USA
| | - Teresa A Rose-Hellekant
- Department of Biomedical Sciences, Medical School, University of Minnesota, Duluth, MN 55812, USA and
| |
Collapse
|
14
|
Tao QQ, Sun YM, Liu ZJ, Yang P, Li HL, Lu SJ, Wu ZY. Lack of association between CALHM1 p.P86L variation and Alzheimer's disease in the Han Chinese population. Neurobiol Aging 2014; 35:1956.e13-4. [PMID: 24630757 DOI: 10.1016/j.neurobiolaging.2014.02.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 02/11/2014] [Accepted: 02/16/2014] [Indexed: 11/23/2022]
Abstract
In recent years, several studies have reported calcium homeostasis modulator 1 (CALHM1) was a potential gene related to Alzheimer's disease (AD) susceptibility. However, whether CALHM1 p.P86L variation (rs2986017), a risk factor for AD is still controversial. Two independent studies have been performed in the Chinese population and the conclusions have not reached an agreement. In the present study, we performed a replication case-control study in 1301 Chinese subjects including 452 sporadic AD patients and 849 unrelated age and gender-matched controls, to determine whether this variation is a risk factor for AD in the Han Chinese population. We failed to replicate the positive association between the CALHM1 p.P86L variation and AD. In addition, we also examined p.P86L variation in a meta-analysis of 5 independent studies performed in Chinese and other Asian populations and negative association was found in total 2328 AD patients and 2865 controls. Our study suggests that CALHM1 p.P86L variation may not be an AD susceptibility factor in the Han Chinese population.
Collapse
|
15
|
Abstract
Not only is ATP a ubiquitous source of energy but it is also used widely as an intercellular signal. For example, keratinocytes release ATP in response to numerous external stimuli including pressure, heat, and chemical insult. The released ATP activates purinergic receptors on nerve fibers to generate nociceptive signals. The importance of an ATP signal in epithelial-to-neuronal signaling is nowhere more evident than in the taste system. The receptor cells of taste buds release ATP in response to appropriate stimulation by tastants and the released ATP then activates P2X2 and P2X3 receptors on the taste nerves. Genetic ablation of the relevant P2X receptors leaves an animal without the ability to taste any primary taste quality. Of interest is that release of ATP by taste receptor cells occurs in a non-vesicular fashion, apparently via gated membrane channels. Further, in keeping with the crucial role of ATP as a neurotransmitter in this system, a subset of taste cells expresses a specific ectoATPase, NTPDase2, necessary to clear extracellular ATP which otherwise will desensitize the P2X receptors on the taste nerves. The unique utilization of ATP as a key neurotransmitter in the taste system may reflect the epithelial rather than neuronal origins of the receptor cells.
Collapse
Affiliation(s)
- Sue C Kinnamon
- Department of Otolaryngology, Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine Aurora, CO, USA
| | - Thomas E Finger
- Department Cell and Developmental Biology, Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine Aurora, CO, USA
| |
Collapse
|