1
|
Schreiber R, Ousingsawat J, Kunzelmann K. The anoctamins: Structure and function. Cell Calcium 2024; 120:102885. [PMID: 38642428 DOI: 10.1016/j.ceca.2024.102885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/22/2024]
Abstract
When activated by increase in intracellular Ca2+, anoctamins (TMEM16 proteins) operate as phospholipid scramblases and as ion channels. Anoctamin 1 (ANO1) is the Ca2+-activated epithelial anion-selective channel that is coexpressed together with the abundant scramblase ANO6 and additional intracellular anoctamins. In salivary and pancreatic glands, ANO1 is tightly packed in the apical membrane and secretes Cl-. Epithelia of airways and gut use cystic fibrosis transmembrane conductance regulator (CFTR) as an apical Cl- exit pathway while ANO1 supports Cl- secretion mainly by facilitating activation of luminal CFTR and basolateral K+ channels. Under healthy conditions ANO1 modulates intracellular Ca2+ signals by tethering the endoplasmic reticulum, and except of glands its direct secretory contribution as Cl- channel might be small, compared to CFTR. In the kidneys ANO1 supports proximal tubular acid secretion and protein reabsorption and probably helps to excrete HCO3-in the collecting duct epithelium. However, under pathological conditions as in polycystic kidney disease, ANO1 is strongly upregulated and may cause enhanced proliferation and cyst growth. Under pathological condition, ANO1 and ANO6 are upregulated and operate as secretory channel/phospholipid scramblases, partly by supporting Ca2+-dependent processes. Much less is known about the role of other epithelial anoctamins whose potential functions are discussed in this review.
Collapse
Affiliation(s)
- Rainer Schreiber
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Jiraporn Ousingsawat
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, University street 31, D-93053 Regensburg, Germany.
| |
Collapse
|
2
|
Nguyen DM, Chen TY. Structure and Function of Calcium-Activated Chloride Channels and Phospholipid Scramblases in the TMEM16 Family. Handb Exp Pharmacol 2024; 283:153-180. [PMID: 35792944 DOI: 10.1007/164_2022_595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The transmembrane protein 16 (TMEM16) family consists of Ca2+-activated chloride channels and phospholipid scramblases. Ten mammalian TMEM16 proteins, TMEM16A-K (with no TMEM16I), and several non-mammalian TMEM16 proteins, such as afTMEM16 and nhTMEM16, have been discovered. All known TMEM16 proteins are homodimeric proteins containing two subunits. Each subunit consists of ten transmembrane helices with Ca2+-binding sites and a single ion-permeation/phospholipid transport pathway. The ion-permeation pathway and the phospholipid transport pathway of TMEM16 proteins have a wide intracellular vestibule, a narrow neck, and a smaller extracellular vestibule. Interestingly, the lining wall of the ion-permeation/phospholipid transport pathway may be formed, at least partially, by membrane phospholipids, though the degree of pore-wall forming by phospholipids likely varies among TMEM16 proteins. Thus, the biophysical properties and activation mechanisms of TMEM16 proteins could differ from each other accordingly. Here we review the current understanding of the structure and function of TMEM16 molecules.
Collapse
Affiliation(s)
- Dung Manh Nguyen
- Center for Neuroscience, University of California, Davis, CA, USA.
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Tsung-Yu Chen
- Department of Neurology, Center for Neuroscience, University of California, Davis, CA, USA.
| |
Collapse
|
3
|
Lee J, Kim S, Lee B, Kim YB, Kim KH, Chung G, Lee SJ, Lee S, Sun W, Park HK, Choi SY. Major depression-related factor NEGR1 controls salivary secretion in mouse submandibular glands. iScience 2023; 26:106773. [PMID: 37216094 PMCID: PMC10196562 DOI: 10.1016/j.isci.2023.106773] [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: 09/06/2022] [Revised: 02/26/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Salivary gland cells, which secrete water in response to neuronal stimulation, are closely connected to other neurons. Transcriptomic studies show that salivary glands also express some proteins responsible for neuronal function. However, the physiological functions of these common neuro-exocrine factors in salivary glands are largely unknown. Here, we studied the function of Neuronal growth regulator 1 (NEGR1) in the salivary gland cells. NEGR1 was also expressed in mouse and human salivary glands. The structure of salivary glands of Negr1 knockout (KO) mice was normal. Negr1 KO mice showed tempered carbachol- or thapsigargin-induced intracellular Ca2+ increases and store-operated Ca2+ entry. Of interest, the activity of the large-conductance Ca2+-activated K+ channel (BK channel) was increased, whereas Ca2+-activated Cl- channel ANO1 channel activity was not altered in Negr1 KO mice. Pilocarpine- and carbachol-induced salivation was decreased in Negr1 KO mice. These results suggest that NEGR1 influence salivary secretion though the muscarinic Ca2+ signaling.
Collapse
Affiliation(s)
- Jisoo Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Soohyun Kim
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Boram Lee
- Department of Anatomy, Brain Korea 21 Plus Program for Biomedical Science, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Yoo-Bin Kim
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Kwang Hwan Kim
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Gehoon Chung
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Sung Joong Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Soojin Lee
- Department of Microbiology and Molecular Biology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Woong Sun
- Department of Anatomy, Brain Korea 21 Plus Program for Biomedical Science, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Hee-Kyung Park
- Department of Oral Medicine and Oral Diagnosis, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Republic of Korea
| |
Collapse
|
4
|
Song C, Chai Z, Chen S, Zhang H, Zhang X, Zhou Y. Intestinal mucus components and secretion mechanisms: what we do and do not know. Exp Mol Med 2023; 55:681-691. [PMID: 37009791 PMCID: PMC10167328 DOI: 10.1038/s12276-023-00960-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/26/2022] [Indexed: 04/04/2023] Open
Abstract
Damage to the colon mucus barrier, the first line of defense against microorganisms, is an important determinant of intestinal diseases such as inflammatory bowel disease and colorectal cancer, and disorder in extraintestinal organs. The mucus layer has attracted the attention of the scientific community in recent years, and with the discovery of new mucosal components, it has become increasingly clear that the mucosal barrier is a complex system composed of many components. Moreover, certain components are jointly involved in regulating the structure and function of the mucus barrier. Therefore, a comprehensive and systematic understanding of the functional components of the mucus layer is clearly warranted. In this review, we summarize the various functional components of the mucus layer identified thus far and describe their unique roles in shaping mucosal structure and function. Furthermore, we detail the mechanisms underlying mucus secretion, including baseline and stimulated secretion. In our opinion, baseline secretion can be categorized into spontaneous Ca2+ oscillation-mediated slow and continuous secretion and stimulated secretion, which is mediated by massive Ca2+ influx induced by exogenous stimuli. This review extends the current understanding of the intestinal mucus barrier, with an emphasis on host defense strategies based on fortification of the mucus layer.
Collapse
Affiliation(s)
- Chunyan Song
- Department of Preventive Medicine, Health Science Center, Ningbo University, Zhejiang Key Laboratory of Pathophysiology, Ningbo, Zhejiang, 315211, China
| | - Zhenglong Chai
- Department of Preventive Medicine, Health Science Center, Ningbo University, Zhejiang Key Laboratory of Pathophysiology, Ningbo, Zhejiang, 315211, China
| | - Si Chen
- Department of Preventive Medicine, Health Science Center, Ningbo University, Zhejiang Key Laboratory of Pathophysiology, Ningbo, Zhejiang, 315211, China
| | - Hui Zhang
- Department of Preventive Medicine, Health Science Center, Ningbo University, Zhejiang Key Laboratory of Pathophysiology, Ningbo, Zhejiang, 315211, China
| | - Xiaohong Zhang
- Department of Preventive Medicine, Health Science Center, Ningbo University, Zhejiang Key Laboratory of Pathophysiology, Ningbo, Zhejiang, 315211, China.
- The Affiliated Hospital of Medical School, Ningbo University, Institute of Digestive Disease of Ningbo University, Ningbo, Zhejiang, 315020, China.
| | - Yuping Zhou
- The Affiliated Hospital of Medical School, Ningbo University, Institute of Digestive Disease of Ningbo University, Ningbo, Zhejiang, 315020, China.
| |
Collapse
|
5
|
Analysis of a cell niche with proliferative potential at the roof of the aqueduct of Sylvius. Neurosci Res 2023; 188:28-38. [PMID: 36375656 DOI: 10.1016/j.neures.2022.11.004] [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: 10/19/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
Abstract
The aqueduct of Sylvius connects the third with the fourth ventricle and is surrounded by the Periaqueductal Grey. Here, we report a novel niche of cells in the dorsal section of the aqueduct, hereby named dorsal aqueduct niche or DAN, by applying a battery of selective markers and transgenic mouse lines. The somata of DAN cells are located toward the lumen of the ventricle forming multiple layers in close association with the cerebrospinal fluid (CSF). A single process emerges from the soma and run with the blood vessels. Cells of the DAN express radial glia/stem cell markers such as GFAP, vimentin and nestin, and the glutamate transporter GLAST or the oligodendrocyte precursor/pericyte marker NG2, thereby suggesting their potential for the generation of new cells. Morphologically, DAN cells resemble tanycytes of the third ventricle, which transfer biochemical signals from the CSF to the central nervous system and display proliferative capacity. The aqueduct ependymal lining can proliferate as observed by the integration of BrdU and expression of Ki67. Thus, the dorsal section of the aqueduct of Sylvius possesses cells that may act a niche of new glial cells in the adult mouse brain.
Collapse
|
6
|
Villalobo A. Regulation of ErbB Receptors by the Ca2+ Sensor Protein Calmodulin in Cancer. Biomedicines 2023; 11:biomedicines11030661. [PMID: 36979639 PMCID: PMC10045772 DOI: 10.3390/biomedicines11030661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 02/24/2023] Open
Abstract
Overexpression and mutations of the epidermal growth factor receptor (EGFR/ErbB1/HER1) and other tyrosine kinase receptors of the ErbB family (ErbB2/HER2, ErbB3/HER3 and ErbB4/HER4) play an essential role in enhancing the proliferation, the migratory capacity and invasiveness of many tumor cells, leading to cancer progression and increased malignancy. To understand these cellular processes in detail is essential to understand at a molecular level the signaling pathways and regulatory mechanisms controlling these receptors. In this regard, calmodulin (CaM) is a Ca2+-sensor protein that directly interacts with and regulates ErbB receptors, as well as some CaM-dependent kinases that also regulate these receptors, particularly EGFR and ErbB2, adding an additional layer of CaM-dependent regulation to this system. In this short review, an update of recent advances in this area is presented, covering the direct action of Ca2+/CaM on the four ErbB family members mostly in tumor cells and the indirect action of Ca2+/CaM on the receptors via CaM-regulated kinases. It is expected that further understanding of the CaM-dependent mechanisms regulating the ErbB receptors in future studies could identify new therapeutic targets in these systems that could help to control or delay cancer progression.
Collapse
Affiliation(s)
- Antonio Villalobo
- Cancer and Human Molecular Genetics Area-Oto-Neurosurgery Research Group, University Hospital La Paz Research Institute (IdiPAZ), Paseo de la Castellana 261, E-28046 Madrid, Spain
| |
Collapse
|
7
|
Sim JR, Shin DH, Park PG, Park SH, Bae JY, Lee Y, Kang DY, Kim YJ, Aum S, Noh SH, Hwang SJ, Cha HR, Kim CB, Ko SH, Park S, Jeon D, Cho S, Lee GE, Kim J, Moon YH, Kim JO, Nam JS, Kim CH, Moon S, Chung YW, Park MS, Ryu JH, Namkung W, Lee JM, Lee MG. Amelioration of SARS-CoV-2 infection by ANO6 phospholipid scramblase inhibition. Cell Rep 2022; 40:111117. [PMID: 35839776 PMCID: PMC9250890 DOI: 10.1016/j.celrep.2022.111117] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 05/27/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022] Open
Abstract
As an enveloped virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delivers its viral genome into host cells via fusion of the viral and cell membranes. Here, we show that ANO6/TMEM16F-mediated cell surface exposure of phosphatidylserine is critical for SARS-CoV-2 entry and that ANO6-selective inhibitors are effective against SARS-CoV-2 infections. Application of the SARS-CoV-2 Spike pseudotyped virus (SARS2-PsV) evokes a cytosolic Ca2+ elevation and ANO6-dependent phosphatidylserine externalization in ACE2/TMPRSS2-positive mammalian cells. A high-throughput screening of drug-like chemical libraries identifies three different structural classes of chemicals showing ANO6 inhibitory effects. Among them, A6-001 displays the highest potency and ANO6 selectivity and it inhibits the single-round infection of SARS2-PsV in ACE2/TMPRSS2-positive HEK 293T cells. More importantly, A6-001 strongly inhibits authentic SARS-CoV-2-induced phosphatidylserine scrambling and SARS-CoV-2 viral replications in Vero, Calu-3, and primarily cultured human nasal epithelial cells. These results provide mechanistic insights into the viral entry process and offer a potential target for pharmacological intervention to protect against coronavirus disease 2019 (COVID-19).
Collapse
Affiliation(s)
- Ju-Ri Sim
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Pil-Gu Park
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - So-Hyeon Park
- College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983, Korea
| | - Joon-Yong Bae
- Department of Microbiology, Institute for Viral Diseases, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Youngchae Lee
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Dha-Yei Kang
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Ye Jin Kim
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Sowon Aum
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Shin Hye Noh
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea; Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Su Jin Hwang
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hye-Ran Cha
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Cheong Bi Kim
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Si Hwan Ko
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Sunghoon Park
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Dongkyu Jeon
- College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983, Korea
| | - Sungwoo Cho
- College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983, Korea
| | - Gee Eun Lee
- Department of Microbiology, Institute for Viral Diseases, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Jeonghun Kim
- Department of Microbiology, Institute for Viral Diseases, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Young-Hye Moon
- Science Unit, International Vaccine Institute, Seoul 08826, Korea
| | - Jae-Ouk Kim
- Science Unit, International Vaccine Institute, Seoul 08826, Korea
| | - Jae-Sung Nam
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Chang-Hoon Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Sungmin Moon
- Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Youn Wook Chung
- Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Man-Seong Park
- Department of Microbiology, Institute for Viral Diseases, Korea University College of Medicine, Seoul 02841, Republic of Korea
| | - Ji-Hwan Ryu
- Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea.
| | - Wan Namkung
- College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983, Korea.
| | - Jae Myun Lee
- Department of Microbiology and Immunology, Institute for Immunology and Immunological Diseases, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea.
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea; Severance Biomedical Science Institute, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 03722, Korea.
| |
Collapse
|
8
|
Al-Hosni R, Ilkan Z, Agostinelli E, Tammaro P. The pharmacology of the TMEM16A channel: therapeutic opportunities. Trends Pharmacol Sci 2022; 43:712-725. [PMID: 35811176 DOI: 10.1016/j.tips.2022.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/15/2022]
Abstract
The TMEM16A Ca2+-gated Cl- channel is involved in a variety of vital physiological functions and may be targeted pharmacologically for therapeutic benefit in diseases such as hypertension, stroke, and cystic fibrosis (CF). The determination of the TMEM16A structure and high-throughput screening efforts, alongside ex vivo and in vivo animal studies and clinical investigations, are hastening our understanding of the physiology and pharmacology of this channel. Here, we offer a critical analysis of recent developments in TMEM16A pharmacology and reflect on the therapeutic opportunities provided by this target.
Collapse
Affiliation(s)
- Rumaitha Al-Hosni
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Zeki Ilkan
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Emilio Agostinelli
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Paolo Tammaro
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| |
Collapse
|
9
|
A Mathematical Model of Salivary Gland Duct Cells. Bull Math Biol 2022; 84:84. [PMID: 35799078 PMCID: PMC9262821 DOI: 10.1007/s11538-022-01041-3] [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: 03/05/2022] [Accepted: 06/14/2022] [Indexed: 11/18/2022]
Abstract
Saliva is produced in two stages in the salivary glands: the secretion of primary saliva by the acinus and the modification of saliva composition to final saliva by the intercalated and striated ducts. In order to understand the saliva modification process, we develop a mathematical model for the salivary gland duct. The model utilises the realistic 3D structure of the duct reconstructed from an image stack of gland tissue. Immunostaining results show that TMEM16A and aquaporin are expressed in the intercalated duct cells and that ENaC is not. Based on this, the model predicts that the intercalated duct does not absorb Na\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$^+$$\end{document}+ and Cl\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$^-$$\end{document}- like the striated duct but secretes a small amount of water instead. The input to the duct model is the time-dependent primary saliva generated by an acinar cell model. Our duct model produces final saliva output that agrees with the experimental measurements at various stimulation levels. It also shows realistic biological features such as duct cell volume, cellular concentrations and membrane potentials. Simplification of the model by omission of all detailed 3D structures of the duct makes a negligible difference to the final saliva output. This shows that saliva production is not sensitive to structural variation of the duct.
Collapse
|
10
|
Galietta LJ. TMEM16A (ANO1) as a therapeutic target in cystic fibrosis. Curr Opin Pharmacol 2022; 64:102206. [DOI: 10.1016/j.coph.2022.102206] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 01/02/2023]
|
11
|
Anoctamin 1 controls bone resorption by coupling Cl - channel activation with RANKL-RANK signaling transduction. Nat Commun 2022; 13:2899. [PMID: 35610255 PMCID: PMC9130328 DOI: 10.1038/s41467-022-30625-9] [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: 07/21/2021] [Accepted: 05/05/2022] [Indexed: 12/18/2022] Open
Abstract
Osteoclast over-activation leads to bone loss and chloride homeostasis is fundamental importance for osteoclast function. The calcium-activated chloride channel Anoctamin 1 (also known as TMEM16A) is an important chloride channel involved in many physiological processes. However, its role in osteoclast remains unresolved. Here, we identified the existence of Anoctamin 1 in osteoclast and show that its expression positively correlates with osteoclast activity. Osteoclast-specific Anoctamin 1 knockout mice exhibit increased bone mass and decreased bone resorption. Mechanistically, Anoctamin 1 deletion increases intracellular Cl- concentration, decreases H+ secretion and reduces bone resorption. Notably, Anoctamin 1 physically interacts with RANK and this interaction is dependent upon Anoctamin 1 channel activity, jointly promoting RANKL-induced downstream signaling pathways. Anoctamin 1 protein levels are substantially increased in osteoporosis patients and this closely correlates with osteoclast activity. Finally, Anoctamin 1 deletion significantly alleviates ovariectomy induced osteoporosis. These results collectively establish Anoctamin 1 as an essential regulator in osteoclast function and suggest a potential therapeutic target for osteoporosis.
Collapse
|
12
|
Li H, Yu Z, Wang H, Wang N, Sun X, Yang S, Hua X, Liu Z. Role of ANO1 in tumors and tumor immunity. J Cancer Res Clin Oncol 2022; 148:2045-2068. [PMID: 35471604 DOI: 10.1007/s00432-022-04004-2] [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: 07/31/2021] [Accepted: 03/29/2022] [Indexed: 12/24/2022]
Abstract
Dysregulation of gene amplification, cell-signaling-pathway transduction, epigenetic and transcriptional regulation, and protein interactions drives tumor-cell proliferation and invasion, while ion channels also play an important role in the generation and development of tumor cells. Overexpression of Ca2+-activated Cl- channel anoctamin 1 (ANO1) is shown in numerous cancer types and correlates with poor prognosis. However, the mechanisms involved in ANO1-mediated malignant cellular transformation and the role of ANO1 in tumor immunity remain unknown. In this review, we discuss recent studies to determine the role of ANO1 in tumorigenesis and provide novel insights into the role of ANO1 in the context of tumor immunity. Furthermore, we analyze the roles and potential mechanisms of ANO1 in different types of cancers, and provide novel notions for the role of ANO1 in the tumor microenvironment and for potential use of ANO1 in clinical applications. Our review shows that ANO1 is involved in tumor immunity and microenvironment, and may, therefore, be an effective biomarker and therapeutic drug target.
Collapse
Affiliation(s)
- Haini Li
- Department of Gastroenterology, Qingdao Sixth People's Hospital, Qingdao, 266001, China
| | - Zongxue Yu
- Department of Endocrinology, Affiliated Qingdao Third People's Hospital, Qingdao University, Qingdao, 266001, China
| | - Haiyan Wang
- Department of Clinical Laboratory, Affiliated Qingdao Third People's Hospital, Qingdao University, Qingdao, 266021, China
| | - Ning Wang
- Department of Clinical Laboratory, Affiliated Qingdao Third People's Hospital, Qingdao University, Qingdao, 266021, China
| | - Xueguo Sun
- Department of Gastroenterology, Qingdao University Affiliated Hospital, Qingdao, 266001, China
| | - Shengmei Yang
- Department of Gynecology, Qingdao University Affiliated Hospital, Qingdao, 266001, China
| | - Xu Hua
- Department of Clinical Laboratory, Affiliated Qingdao Third People's Hospital, Qingdao University, Qingdao, 266021, China
| | - Zongtao Liu
- Department of Clinical Laboratory, Affiliated Qingdao Third People's Hospital, Qingdao University, Qingdao, 266021, China.
| |
Collapse
|
13
|
Nikolovska K, Cao L, Hensel I, Di Stefano G, Seidler A, Zhou K, Qian J, Singh AK, Riederer B, Seidler U. Sodium/hydrogen-exchanger-2 modulates colonocyte lineage differentiation. Acta Physiol (Oxf) 2022; 234:e13774. [PMID: 34985202 DOI: 10.1111/apha.13774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/12/2021] [Accepted: 01/01/2022] [Indexed: 12/11/2022]
Abstract
AIM The sodium/hydrogen exchanger 2 (NHE2) is an intestinal acid extruder with crypt-predominant localization and unresolved physiological significance. Our aim was to decipher its role in colonic epithelial cell proliferation, differentiation and electrolyte transport. METHODS Alterations induced by NHE2-deficiency were addressed in murine nhe2-/- and nhe2+/+ colonic crypts and colonoids, and NHE2-knockdown and control Caco2Bbe cells using pH-fluorometry, gene expression analysis and immunofluorescence. RESULTS pHi -measurements along the colonic cryptal axis revealed significantly decreased intracellular pH (pHi ) in the middle segment of nhe2-/- compared to nhe2+/+ crypts. Increased Nhe2 mRNA expression was detected in murine colonoids in the transiently amplifying/progenitor cell stage (TA/PE). Lack of Nhe2 altered the differentiation programme of colonic epithelial cells with reduced expression of absorptive lineage markers alkaline phosphatase (iAlp), Slc26a3 and transcription factor hairy and enhancer-of-split 1 (Hes1), but increased expression of secretory lineage markers Mucin 2, trefoil factor 3 (Tff3), enteroendocrine marker chromogranin A and murine atonal homolog 1 (Math1). Enterocyte differentiation was found to be pHi dependent with acidic pHi reducing, and alkaline pHi stimulating the expression of enterocyte differentiation markers in Caco2Bbe cells. A thicker mucus layer, longer crypts and an expanded brush border membrane zone of sodium/hydrogen exchanger 3 (NHE3) abundance may explain the lack of inflammation and the normal fluid absorptive rate in nhe2-/- colon. CONCLUSIONS The results suggest that NHE2 expression is activated when colonocytes emerge from the stem cell niche. Its activity increases progenitor cell pHi and thereby supports absorptive enterocyte differentiation.
Collapse
Affiliation(s)
- Katerina Nikolovska
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Li Cao
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
- Department of Gastroenterology Tongji Hospital Huazhong University Wuhan China
| | - Inga Hensel
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Gabriella Di Stefano
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Anna Elisabeth Seidler
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Kunyan Zhou
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Jiajie Qian
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
- Department of Transplantation and Hepatobiliary Surgery First Affiliated Hospital of Zheijang University Hangzhou China
| | - Anurag Kumar Singh
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
- Department of Physiological Chemistry University of Halle Halle (Saale) Germany
| | - Brigitte Riederer
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany
| |
Collapse
|
14
|
Polymodal Control of TMEM16x Channels and Scramblases. Int J Mol Sci 2022; 23:ijms23031580. [PMID: 35163502 PMCID: PMC8835819 DOI: 10.3390/ijms23031580] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/20/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
The TMEM16A/anoctamin-1 calcium-activated chloride channel (CaCC) contributes to a range of vital functions, such as the control of vascular tone and epithelial ion transport. The channel is a founding member of a family of 10 proteins (TMEM16x) with varied functions; some members (i.e., TMEM16A and TMEM16B) serve as CaCCs, while others are lipid scramblases, combine channel and scramblase function, or perform additional cellular roles. TMEM16x proteins are typically activated by agonist-induced Ca2+ release evoked by Gq-protein-coupled receptor (GqPCR) activation; thus, TMEM16x proteins link Ca2+-signalling with cell electrical activity and/or lipid transport. Recent studies demonstrate that a range of other cellular factors—including plasmalemmal lipids, pH, hypoxia, ATP and auxiliary proteins—also control the activity of the TMEM16A channel and its paralogues, suggesting that the TMEM16x proteins are effectively polymodal sensors of cellular homeostasis. Here, we review the molecular pathophysiology, structural biology, and mechanisms of regulation of TMEM16x proteins by multiple cellular factors.
Collapse
|
15
|
Hawn MB, Akin E, Hartzell H, Greenwood IA, Leblanc N. Molecular mechanisms of activation and regulation of ANO1-Encoded Ca 2+-Activated Cl - channels. Channels (Austin) 2021; 15:569-603. [PMID: 34488544 PMCID: PMC8480199 DOI: 10.1080/19336950.2021.1975411] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 08/29/2021] [Indexed: 01/13/2023] Open
Abstract
Ca2+-activated Cl- channels (CaCCs) perform a multitude of functions including the control of cell excitability, regulation of cell volume and ionic homeostasis, exocrine and endocrine secretion, fertilization, amplification of olfactory sensory function, and control of smooth muscle cell contractility. CaCCs are the translated products of two members (ANO1 and ANO2, also known as TMEM16A and TMEM16B) of the Anoctamin family of genes comprising ten paralogs. This review focuses on recent progress in understanding the molecular mechanisms involved in the regulation of ANO1 by cytoplasmic Ca2+, post-translational modifications, and how the channel protein interacts with membrane lipids and protein partners. After first reviewing the basic properties of native CaCCs, we then present a brief historical perspective highlighting controversies about their molecular identity in native cells. This is followed by a summary of the fundamental biophysical and structural properties of ANO1. We specifically address whether the channel is directly activated by internal Ca2+ or indirectly through the intervention of the Ca2+-binding protein Calmodulin (CaM), and the structural domains responsible for Ca2+- and voltage-dependent gating. We then review the regulation of ANO1 by internal ATP, Calmodulin-dependent protein kinase II-(CaMKII)-mediated phosphorylation and phosphatase activity, membrane lipids such as the phospholipid phosphatidyl-(4,5)-bisphosphate (PIP2), free fatty acids and cholesterol, and the cytoskeleton. The article ends with a survey of physical and functional interactions of ANO1 with other membrane proteins such as CLCA1/2, inositol trisphosphate and ryanodine receptors in the endoplasmic reticulum, several members of the TRP channel family, and the ancillary Κ+ channel β subunits KCNE1/5.
Collapse
Affiliation(s)
- M. B. Hawn
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - E. Akin
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - H.C. Hartzell
- Department of Cell Biology, Emory University School of Medicine, USA
| | - I. A. Greenwood
- Department of Vascular Pharmacology, St. George’s University of London, UK
| | - N. Leblanc
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| |
Collapse
|
16
|
TMEM16A/ANO1: Current Strategies and Novel Drug Approaches for Cystic Fibrosis. Cells 2021; 10:cells10112867. [PMID: 34831090 PMCID: PMC8616501 DOI: 10.3390/cells10112867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/19/2022] Open
Abstract
Cystic fibrosis (CF) is the most common of rare hereditary diseases in Caucasians, and it is estimated to affect 75,000 patients globally. CF is a complex disease due to the multiplicity of mutations found in the CF transmembrane conductance regulator (CFTR) gene causing the CFTR protein to become dysfunctional. Correctors and potentiators have demonstrated good clinical outcomes for patients with specific gene mutations; however, there are still patients for whom those treatments are not suitable and require alternative CFTR-independent strategies. Although CFTR is the main chloride channel in the lungs, others could, e.g., anoctamin-1 (ANO1 or TMEM16A), compensate for the deficiency of CFTR. This review summarizes the current knowledge on calcium-activated chloride channel (CaCC) ANO1 and presents ANO1 as an exciting target in CF.
Collapse
|
17
|
Calmodulin-Dependent Regulation of Overexpressed but Not Endogenous TMEM16A Expressed in Airway Epithelial Cells. MEMBRANES 2021; 11:membranes11090723. [PMID: 34564540 PMCID: PMC8471323 DOI: 10.3390/membranes11090723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 11/30/2022]
Abstract
Regulation of the Ca2+-activated Cl− channel TMEM16A by Ca2+/calmodulin (CAM) is discussed controversially. In the present study, we compared regulation of TMEM16A by Ca2+/calmodulin (holo-CAM), CAM-dependent kinase (CAMKII), and CAM-dependent phosphatase calcineurin in TMEM16A-overexpressing HEK293 cells and TMEM16A expressed endogenously in airway and colonic epithelial cells. The activator of the Ca2+/CAM-regulated K+ channel KCNN4, 1-EBIO, activated TMEM16A in overexpressing cells, but not in cells with endogenous expression of TMEM16A. Evidence is provided that CAM-interaction with TMEM16A modulates the Ca2+ sensitivity of the Cl− channel. Enhanced Ca2+ sensitivity of overexpressed TMEM16A explains its activity at basal (non-elevated) intracellular Ca2+ levels. The present results correspond well to a recent report that demonstrates a Ca2+-unbound form of CAM (apo-CAM) that is pre-associated with TMEM16A and mediates a Ca2+-dependent sensitization of activation (and inactivation). However, when using activators or inhibitors for holo-CAM, CAMKII, or calcineurin, we were unable to detect a significant impact of CAM, and limit evidence for regulation by CAM-dependent regulatory proteins on receptor-mediated activation of endogenous TMEM16A in airway or colonic epithelial cells. We propose that regulatory properties of TMEM16A and and other members of the TMEM16 family as detected in overexpression studies, should be validated for endogenous TMEM16A and physiological stimuli such as activation of phospholipase C (PLC)-coupled receptors.
Collapse
|
18
|
Zhao W, Zhang L, Ermilov LG, Colmenares Aguilar MG, Linden DR, Eisenman ST, Romero MF, Farrugia G, Sha L, Gibbons SJ. Bicarbonate ion transport by the electrogenic Na + /HCO 3- cotransporter, NBCe1, is required for normal electrical slow-wave activity in mouse small intestine. Neurogastroenterol Motil 2021; 33:e14149. [PMID: 33837991 PMCID: PMC8485339 DOI: 10.1111/nmo.14149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/26/2021] [Accepted: 03/21/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Normal gastrointestinal motility depends on electrical slow-wave activity generated by interstitial cells of Cajal (ICC) in the tunica muscularis of the gastrointestinal tract. A requirement for HCO3- in extracellular solutions used to record slow waves indicates a role for HCO3- transport in ICC pacemaking. The Slc4a4 gene transcript encoding the electrogenic Na+ /HCO3- cotransporter, NBCe1, is enriched in mouse small intestinal myenteric region ICC (ICC-MY) that generate slow waves. This study aimed to determine how extracellular HCO3- concentrations affect electrical activity in mouse small intestine and to determine the contribution of NBCe1 activity to these effects. METHODS Immunohistochemistry and sharp electrode electrical recordings were used. KEY RESULTS The NBCe1 immunoreactivity was localized to ICC-MY of the tunica muscularis. In sharp electrode electrical recordings, removal of HCO3- from extracellular solutions caused significant, reversible, depolarization of the smooth muscle and a reduction in slow-wave amplitude and frequency. In 100 mM HCO3- , the muscle hyperpolarized and slow wave amplitude and frequency increased. The effects of replacing extracellular Na+ with Li+ , an ion that does not support NBCe1 activity, were similar to, but larger than, the effects of removing HCO3- . There were no additional changes to electrical activity when HCO3- was removed from Li+ containing solutions. The Na+ /HCO3- cotransport inhibitor, S-0859 (30µM) significantly reduced the effect of removing HCO3- on electrical activity. CONCLUSIONS & INFERENCES These studies demonstrate a major role for Na+ /HCO3- cotransport by NBCe1 in electrical activity of mouse small intestine and indicated that regulation of intracellular acid:base homeostasis contributes to generation of normal pacemaker activity in the gastrointestinal tract.
Collapse
Affiliation(s)
- Wenchang Zhao
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Liwen Zhang
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Leonid G. Ermilov
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Maria Gabriela Colmenares Aguilar
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - David R. Linden
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Seth T. Eisenman
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Michael F. Romero
- Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Gianrico Farrugia
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA
| | - Lei Sha
- Neuroendocrine Pharmacology, China Medical University, Shenyang, Liaoning Province, P. R. China.,Corresponding Authors: Simon J Gibbons, Ph.D., Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. . Telephone: +1 507 284 9652, Lei Sha, M.D., China Medical University, 77 Pu He Road, Shenbei New District, Shenyang, Liaoning Province, P. R. China, 110122, , . Telephone: +86 18900911003
| | - Simon J. Gibbons
- Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Rochester, Minnesota, USA.,Physiology and Biomedical Engineering, Rochester, Minnesota, USA.,Corresponding Authors: Simon J Gibbons, Ph.D., Enteric Neuroscience Program, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, 55905, USA. . Telephone: +1 507 284 9652, Lei Sha, M.D., China Medical University, 77 Pu He Road, Shenbei New District, Shenyang, Liaoning Province, P. R. China, 110122, , . Telephone: +86 18900911003
| |
Collapse
|
19
|
Rehman T, Karp PH, Tan P, Goodell BJ, Pezzulo AA, Thurman AL, Thornell IM, Durfey SL, Duffey ME, Stoltz DA, McKone EF, Singh PK, Welsh MJ. Inflammatory cytokines TNF-α and IL-17 enhance the efficacy of cystic fibrosis transmembrane conductance regulator modulators. J Clin Invest 2021; 131:e150398. [PMID: 34166230 DOI: 10.1172/jci150398] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/22/2021] [Indexed: 12/12/2022] Open
Abstract
Without cystic fibrosis transmembrane conductance regulator-mediated (CFTR-mediated) HCO3- secretion, airway epithelia of newborns with cystic fibrosis (CF) produce an abnormally acidic airway surface liquid (ASL), and the decreased pH impairs respiratory host defenses. However, within a few months of birth, ASL pH increases to match that in non-CF airways. Although the physiological basis for the increase is unknown, this time course matches the development of inflammation in CF airways. To learn whether inflammation alters CF ASL pH, we treated CF epithelia with TNF-α and IL-17 (TNF-α+IL-17), 2 inflammatory cytokines that are elevated in CF airways. TNF-α+IL-17 markedly increased ASL pH by upregulating pendrin, an apical Cl-/HCO3- exchanger. Moreover, when CF epithelia were exposed to TNF-α+IL-17, clinically approved CFTR modulators further alkalinized ASL pH. As predicted by these results, in vivo data revealed a positive correlation between airway inflammation and CFTR modulator-induced improvement in lung function. These findings suggest that inflammation is a key regulator of HCO3- secretion in CF airways. Thus, they explain earlier observations that ASL pH increases after birth and indicate that, for similar levels of inflammation, the pH of CF ASL is abnormally acidic. These results also suggest that a non-cell-autonomous mechanism, airway inflammation, is an important determinant of the response to CFTR modulators.
Collapse
Affiliation(s)
- Tayyab Rehman
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Philip H Karp
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and.,Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, USA
| | - Ping Tan
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Brian J Goodell
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Alejandro A Pezzulo
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Andrew L Thurman
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Ian M Thornell
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and
| | - Samantha L Durfey
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | - Michael E Duffey
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - David A Stoltz
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and.,Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Edward F McKone
- National Referral Centre for Adult Cystic Fibrosis, St. Vincent's University Hospital and University College Dublin School of Medicine, Dublin, Ireland
| | - Pradeep K Singh
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | - Michael J Welsh
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine and.,Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, USA.,Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| |
Collapse
|
20
|
Anion and Cation Permeability of the Mouse TMEM16F Calcium-Activated Channel. Int J Mol Sci 2021; 22:ijms22168578. [PMID: 34445284 PMCID: PMC8395294 DOI: 10.3390/ijms22168578] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/31/2021] [Accepted: 08/04/2021] [Indexed: 12/27/2022] Open
Abstract
TMEM16F is involved in several physiological processes, such as blood coagulation, bone development and virus infections. This protein acts both as a Ca2+-dependent phospholipid scramblase and a Ca2+-activated ion channel but several studies have reported conflicting results about the ion selectivity of the TMEM16F-mediated current. Here, we have performed a detailed side-by-side comparison of the ion selectivity of TMEM16F using the whole-cell and inside-out excised patch configurations to directly compare the results. In inside-out configuration, Ca2+-dependent activation was fast and the TMEM16F-mediated current was activated in a few milliseconds, while in whole-cell recordings full activation required several minutes. We determined the relative permeability between Na+ and Cl¯ (PNa/PCl) using the dilution method in both configurations. The TMEM16F-mediated current was highly nonselective, but there were differences depending on the configuration of the recordings. In whole-cell recordings, PNa/PCl was approximately 0.5, indicating a slight preference for Cl¯ permeation. In contrast, in inside-out experiments the TMEM16F channel showed a higher permeability for Na+ with PNa/PCl reaching 3.7. Our results demonstrate that the time dependence of Ca2+ activation and the ion selectivity of TMEM16F depend on the recording configuration.
Collapse
|
21
|
Ion Channels, Transporters, and Sensors Interact with the Acidic Tumor Microenvironment to Modify Cancer Progression. Rev Physiol Biochem Pharmacol 2021; 182:39-84. [PMID: 34291319 DOI: 10.1007/112_2021_63] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Solid tumors, including breast carcinomas, are heterogeneous but typically characterized by elevated cellular turnover and metabolism, diffusion limitations based on the complex tumor architecture, and abnormal intra- and extracellular ion compositions particularly as regards acid-base equivalents. Carcinogenesis-related alterations in expression and function of ion channels and transporters, cellular energy levels, and organellar H+ sequestration further modify the acid-base composition within tumors and influence cancer cell functions, including cell proliferation, migration, and survival. Cancer cells defend their cytosolic pH and HCO3- concentrations better than normal cells when challenged with the marked deviations in extracellular H+, HCO3-, and lactate concentrations typical of the tumor microenvironment. Ionic gradients determine the driving forces for ion transporters and channels and influence the membrane potential. Cancer and stromal cells also sense abnormal ion concentrations via intra- and extracellular receptors that modify cancer progression and prognosis. With emphasis on breast cancer, the current review first addresses the altered ion composition and the changes in expression and functional activity of ion channels and transporters in solid cancer tissue. It then discusses how ion channels, transporters, and cellular sensors under influence of the acidic tumor microenvironment shape cancer development and progression and affect the potential of cancer therapies.
Collapse
|
22
|
Liu Y, Liu Z, Wang K. The Ca 2+-activated chloride channel ANO1/TMEM16A: An emerging therapeutic target for epithelium-originated diseases? Acta Pharm Sin B 2021; 11:1412-1433. [PMID: 34221860 PMCID: PMC8245819 DOI: 10.1016/j.apsb.2020.12.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/19/2020] [Accepted: 09/14/2020] [Indexed: 02/07/2023] Open
Abstract
Anoctamin 1 (ANO1) or TMEM16A gene encodes a member of Ca2+ activated Cl– channels (CaCCs) that are critical for physiological functions, such as epithelial secretion, smooth muscle contraction and sensory signal transduction. The attraction and interest in ANO1/TMEM16A arise from a decade long investigations that abnormal expression or dysfunction of ANO1 is involved in many pathological phenotypes and diseases, including asthma, neuropathic pain, hypertension and cancer. However, the lack of specific modulators of ANO1 has impeded the efforts to validate ANO1 as a therapeutic target. This review focuses on the recent progress made in understanding of the pathophysiological functions of CaCC ANO1 and the current modulators used as pharmacological tools, hopefully illustrating a broad spectrum of ANO1 channelopathy and a path forward for this target validation.
Collapse
Key Words
- ANO1
- ANO1, anoctamin-1
- ASM, airway smooth muscle
- Ang II, angiotensin II
- BBB, blood–brain barrier
- CAMK, Ca2+/calmodulin-dependent protein kinase
- CF, cystic fibrosis
- CFTR, cystic fibrosis transmembrane conductance regulator
- Ca2+-activated Cl– channels (CaCCs)
- CaCCinh-A01
- CaCCs, Ca2+ activated chloride channels
- Cancer
- Cystic fibrosis
- DRG, dorsal root ganglion
- Drug target
- EGFR, epidermal growth factor receptor
- ENaC, epithelial sodium channels
- ER, endoplasmic reticulum
- ESCC, esophageal squamous cell carcinoma
- FRT, fisher rat thyroid
- GI, gastrointestinal
- GIST, gastrointestinal stromal tumor
- GPCR, G-protein coupled receptor
- HNSCC, head and neck squamous cell carcinoma
- HTS, high-throughput screening
- ICC, interstitial cells of Cajal
- IPAH, idiopathic pulmonary arterial hypertension
- MAPK, mitogen-activated protein kinase
- NF-κB, nuclear factor κB
- PAH, pulmonary arterial hypertension
- PAR2, protease activated receptor 2
- PASMC, pulmonary artery smooth muscle cells
- PIP2, phosphatidylinositol 4,5-bisphosphate
- PKD, polycystic kidney disease
- T16Ainh-A01
- TGF-β, transforming growth factor-β
- TMEM16A
- VGCC, voltage gated calcium channel
- VRAC, volume regulated anion channel
- VSMC, vascular smooth muscle cells
- YFP, yellow fluorescent protein
Collapse
Affiliation(s)
- Yani Liu
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China
- Institute of Innovative Drugs, Qingdao University, Qingdao 266021, China
| | - Zongtao Liu
- Department of Clinical Laboratory, Qingdao Third People's Hospital, Qingdao 266041, China
| | - KeWei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao 266073, China
- Institute of Innovative Drugs, Qingdao University, Qingdao 266021, China
- Corresponding authors.
| |
Collapse
|
23
|
Kolesnikov D, Perevoznikova A, Gusev K, Glushankova L, Kaznacheyeva E, Shalygin A. Electrophysiological Properties of Endogenous Single Ca 2+ Activated Cl - Channels Induced by Local Ca 2+ Entry in HEK293. Int J Mol Sci 2021; 22:4767. [PMID: 33946319 PMCID: PMC8124839 DOI: 10.3390/ijms22094767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/19/2022] Open
Abstract
Microdomains formed by proteins of endoplasmic reticulum and plasma membrane play a key role in store-operated Ca2+ entry (SOCE). Ca2+ release through inositol 1,4,5-trisphosphate receptor (IP3R) and subsequent Ca2+ store depletion activate STIM (stromal interaction molecules) proteins, sensors of intraluminal Ca2+, which, in turn, open the Orai channels in plasma membrane. Downstream to this process could be activated TRPC (transient receptor potential-canonical) calcium permeable channels. Using single channel patch-clamp technique we found that a local Ca2+ entry through TRPC1 channels activated endogenous Ca2+-activated chloride channels (CaCCs) with properties similar to Anoctamin6 (TMEM16F). Our data suggest that their outward rectification is based on the dependence from membrane potential of both the channel conductance and the channel activity: (1) The conductance of active CaCCs highly depends on the transmembrane potential (from 3 pS at negative potentials till 60 pS at positive potentials); (2) their activity (NPo) is enhanced with increasing Ca2+ concentration and/or transmembrane potential, conversely lowering of intracellular Ca2+ concentration reduced the open state dwell time; (3) CaCC amplitude is only slightly increased by intracellular Ca2+ concentration. Experiments with Ca2+ buffering by EGTA or BAPTA suggest close local arrangement of functional CaCCs and TRPC1 channels. It is supposed that Ca2+-activated chloride channels are involved in Ca2+ entry microdomains.
Collapse
Affiliation(s)
| | | | | | | | - Elena Kaznacheyeva
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, 194064 St. Petersburg, Russia; (D.K.); (A.P.); (K.G.); (L.G.)
| | - Alexey Shalygin
- Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, 194064 St. Petersburg, Russia; (D.K.); (A.P.); (K.G.); (L.G.)
| |
Collapse
|
24
|
Zajac M, Dreano E, Edwards A, Planelles G, Sermet-Gaudelus I. Airway Surface Liquid pH Regulation in Airway Epithelium Current Understandings and Gaps in Knowledge. Int J Mol Sci 2021; 22:3384. [PMID: 33806154 PMCID: PMC8037888 DOI: 10.3390/ijms22073384] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Knowledge on the mechanisms of acid and base secretion in airways has progressed recently. The aim of this review is to summarize the known mechanisms of airway surface liquid (ASL) pH regulation and their implication in lung diseases. Normal ASL is slightly acidic relative to the interstitium, and defects in ASL pH regulation are associated with various respiratory diseases, such as cystic fibrosis. Basolateral bicarbonate (HCO3-) entry occurs via the electrogenic, coupled transport of sodium (Na+) and HCO3-, and, together with carbonic anhydrase enzymatic activity, provides HCO3- for apical secretion. The latter mainly involves CFTR, the apical chloride/bicarbonate exchanger pendrin and paracellular transport. Proton (H+) secretion into ASL is crucial to maintain its relative acidity compared to the blood. This is enabled by H+ apical secretion, mainly involving H+/K+ ATPase and vacuolar H+-ATPase that carry H+ against the electrochemical potential gradient. Paracellular HCO3- transport, the direction of which depends on the ASL pH value, acts as an ASL protective buffering mechanism. How the transepithelial transport of H+ and HCO3- is coordinated to tightly regulate ASL pH remains poorly understood, and should be the focus of new studies.
Collapse
Affiliation(s)
- Miroslaw Zajac
- Department of Physics and Biophysics, Institute of Biology, Warsaw University of Life Sciences, 02-776 Warsaw, Poland;
| | - Elise Dreano
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
| | - Aurelie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA;
| | - Gabrielle Planelles
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Laboratoire de Physiologie rénale et Tubulopathies, CNRS ERL 8228, 75006 Paris, France
| | - Isabelle Sermet-Gaudelus
- Institut Necker Enfants Malades, INSERM U1151, 75015 Paris, France;
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, 75006 Paris, France;
- Centre de Référence Maladies Rares, Mucoviscidose et Maladies de CFTR, Hôpital Necker Enfants Malades, 75015 Paris, France
- Clinical Trial Network, European Cystic Fibrosis Society, BT2 Belfast, Ireland
- European Respiratory Network Lung, 75006 Paris, France
| |
Collapse
|
25
|
Auer F, Franco Taveras E, Klein U, Kesenheimer C, Fleischhauer D, Möhrlen F, Frings S. Anoctamin 2-chloride channels reduce simple spike activity and mediate inhibition at elevated calcium concentration in cerebellar Purkinje cells. PLoS One 2021; 16:e0247801. [PMID: 33651839 PMCID: PMC7924762 DOI: 10.1371/journal.pone.0247801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/12/2021] [Indexed: 11/19/2022] Open
Abstract
Modulation of neuronal excitability is a prominent way of shaping the activity of neuronal networks. Recent studies highlight the role of calcium-activated chloride currents in this context, as they can both increase or decrease excitability. The calcium-activated chloride channel Anoctamin 2 (ANO2 alias TMEM16B) has been described in several regions of the mouse brain, including the olivo-cerebellar system. In inferior olivary neurons, ANO2 was proposed to increase excitability by facilitating the generation of high-threshold calcium spikes. An expression of ANO2 in cerebellar Purkinje cells was suggested, but its role in these neurons remains unclear. In the present study, we confirmed the expression of Ano2 mRNA in Purkinje cells and performed electrophysiological recordings to examine the influence of ANO2-chloride channels on the excitability of Purkinje cells by comparing wildtype mice to mice lacking ANO2. Recordings were performed in acute cerebellar slices of adult mice, which provided the possibility to study the role of ANO2 within the cerebellar cortex. Purkinje cells were uncoupled from climbing fiber input to assess specifically the effect of ANO2 channels on Purkinje cell activity. We identified an attenuating effect of ANO2-mediated chloride currents on the instantaneous simple spike activity both during strong current injections and during current injections close to the simple spike threshold. Moreover, we report a reduction of inhibitory currents from GABAergic interneurons upon depolarization, lasting for several seconds. Together with the role of ANO2-chloride channels in inferior olivary neurons, our data extend the evidence for a role of chloride-dependent modulation in the olivo-cerebellar system that might be important for proper cerebellum-dependent motor coordination and learning.
Collapse
Affiliation(s)
- Friederike Auer
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Eliana Franco Taveras
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Uli Klein
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Céline Kesenheimer
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Dana Fleischhauer
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Frank Möhrlen
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Stephan Frings
- Department of Animal Physiology, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
- * E-mail:
| |
Collapse
|
26
|
Roh JW, Hwang GE, Kim WK, Nam JH. Ca 2+ Sensitivity of Anoctamin 6/TMEM16F Is Regulated by the Putative Ca 2+-Binding Reservoir at the N-Terminal Domain. Mol Cells 2021; 44:88-100. [PMID: 33658434 PMCID: PMC7941003 DOI: 10.14348/molcells.2021.2203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 01/05/2021] [Accepted: 01/26/2021] [Indexed: 11/27/2022] Open
Abstract
Anoctamin 6/TMEM16F (ANO6) is a dual-function protein with Ca2+-activated ion channel and Ca2+-activated phospholipid scramblase activities, requiring a high intracellular Ca2+ concentration (e.g., half-maximal effective Ca2+ concentration [EC50] of [Ca2+]i > 10 μM), and strong and sustained depolarization above 0 mV. Structural comparison with Anoctamin 1/TMEM16A (ANO1), a canonical Ca2+- activated chloride channel exhibiting higher Ca2+ sensitivity (EC50 of 1 μM) than ANO6, suggested that a homologous Ca2+-transferring site in the N-terminal domain (Nt) might be responsible for the differential Ca2+ sensitivity and kinetics of activation between ANO6 and ANO1. To elucidate the role of the putative Ca2+-transferring reservoir in the Nt (Nt-CaRes), we constructed an ANO6-1-6 chimera in which Nt-CaRes was replaced with the corresponding domain of ANO1. ANO6- 1-6 showed higher sensitivity to Ca2+ than ANO6. However, neither the speed of activation nor the voltage-dependence differed between ANO6 and ANO6-1-6. Molecular dynamics simulation revealed a reduced Ca2+ interaction with Nt- CaRes in ANO6 than ANO6-1-6. Moreover, mutations on potentially Ca2+-interacting acidic amino acids in ANO6 Nt- CaRes resulted in reduced Ca2+ sensitivity, implying direct interactions of Ca2+ with these residues. Based on these results, we cautiously suggest that the net charge of Nt- CaRes is responsible for the difference in Ca2+ sensitivity between ANO1 and ANO6.
Collapse
Affiliation(s)
- Jae Won Roh
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
| | - Ga Eun Hwang
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
| | - Woo Kyung Kim
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Korea
| |
Collapse
|
27
|
Boccaccio A, Menini A, Pifferi S. The cyclic AMP signaling pathway in the rodent main olfactory system. Cell Tissue Res 2021; 383:429-443. [PMID: 33447881 DOI: 10.1007/s00441-020-03391-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/10/2020] [Indexed: 01/15/2023]
Abstract
Odor perception begins with the detection of odorant molecules by the main olfactory epithelium located in the nasal cavity. Odorant molecules bind to and activate a large family of G-protein-coupled odorant receptors and trigger a cAMP-mediated transduction cascade that converts the chemical stimulus into an electrical signal transmitted to the brain. Morever, odorant receptors and cAMP signaling plays a relevant role in olfactory sensory neuron development and axonal targeting to the olfactory bulb. This review will first explore the physiological response of olfactory sensory neurons to odorants and then analyze the different components of cAMP signaling and their different roles in odorant detection and olfactory sensory neuron development.
Collapse
Affiliation(s)
- Anna Boccaccio
- Institute of Biophysics, National Research Council (CNR), Genova, Italy.
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy.,Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
| |
Collapse
|
28
|
Ko W, Jung SR, Kim KW, Yeon JH, Park CG, Nam JH, Hille B, Suh BC. Allosteric modulation of alternatively spliced Ca 2+-activated Cl - channels TMEM16A by PI(4,5)P 2 and CaMKII. Proc Natl Acad Sci U S A 2020; 117:30787-30798. [PMID: 33199590 PMCID: PMC7720229 DOI: 10.1073/pnas.2014520117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Transmembrane 16A (TMEM16A, anoctamin1), 1 of 10 TMEM16 family proteins, is a Cl- channel activated by intracellular Ca2+ and membrane voltage. This channel is also regulated by the membrane phospholipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. We find that two splice variants of TMEM16A show different sensitivity to endogenous PI(4,5)P2 degradation, where TMEM16A(ac) displays higher channel activity and more current inhibition by PI(4,5)P2 depletion than TMEM16A(a). These two channel isoforms differ in the alternative splicing of the c-segment (exon 13). The current amplitude and PI(4,5)P2 sensitivity of both TMEM16A(ac) and (a) are significantly strengthened by decreased free cytosolic ATP and by conditions that decrease phosphorylation by Ca2+/calmodulin-dependent protein kinase II (CaMKII). Noise analysis suggests that the augmentation of currents is due to a rise of single-channel current (i), but not of channel number (N) or open probability (PO). Mutagenesis points to arginine 486 in the first intracellular loop as a putative binding site for PI(4,5)P2, and to serine 673 in the third intracellular loop as a site for regulatory channel phosphorylation that modulates the action of PI(4,5)P2 In silico simulation suggests how phosphorylation of S673 allosterically and differently changes the structure of the distant PI(4,5)P2-binding site between channel splice variants with and without the c-segment exon. In sum, our study reveals the following: differential regulation of alternatively spliced TMEM16A(ac) and (a) by plasma membrane PI(4,5)P2, modification of these effects by channel phosphorylation, identification of the molecular sites, and mechanistic explanation by in silico simulation.
Collapse
Affiliation(s)
- Woori Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
| | - Seung-Ryoung Jung
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Kwon-Woo Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
| | - Jun-Hee Yeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
| | - Cheon-Gyu Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, College of Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
- Ion Channel Disease Research Center, College of Medicine, Dongguk University, Goyang, Gyeonggi-do 10326, Republic of Korea
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Byung-Chang Suh
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea;
| |
Collapse
|
29
|
Lee SP, Chao SC, Chou MF, Huang SF, Dai NT, Wu GJ, Tsai CS, Loh SH, Tsai YT. Characterization of intracellular buffering power in human induced pluripotent stem cells and the loss of pluripotency is delayed by acidic stimulation and increase of NHE1 activity. J Cell Physiol 2020; 236:1515-1528. [PMID: 32841374 DOI: 10.1002/jcp.29959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/18/2020] [Accepted: 07/07/2020] [Indexed: 11/07/2022]
Abstract
The homeostasis of intracellular pH (pHi ) affects many cellular functions. Our previous study has established a functional and molecular model of the active pHi regulators in human induced pluripotent stem cells (hiPSCs). The aims of the present study were to further quantify passive pHi buffering power (β) and to investigate the effects of extracellular pH and Na+ -H+ exchanger 1 (NHE1) activity on pluripotency in hiPSCs. pHi was detected by microspectrofluorimetry with pH-sensitive dye-BCECF. Western blot, immunofluorescence staining, and flow cytometry were used to detect protein expression and pluripotency. Our study in hiPSCs showed that (a) the value of total (βtot ), intrinsic (βi ), and CO2 -dependent ( β C O 2 ) buffering power all increased while pHi increased; (b) during the spontaneous differentiation for 4 days, the β values of βtot and β C O 2 changed in a tendency of decrease, despite the absence of statistical significance; (c) an acidic cultured environment retained pluripotency and further upregulated expression and activity of NHE1 during spontaneous differentiation; (d) inhibition on NHE1 activity promoted the loss of pluripotency. In conclusion, we, for the first time, established a quantitative model of passive β during differentiation and demonstrated that maintenance of NHE1 at a higher level was of critical importance for pluripotency retention in hiPSCs.
Collapse
Affiliation(s)
- Shiao-Pieng Lee
- Department of Dentistry, School of Dentistry, Division of Oral and Maxillofacial Surgery, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan
| | - Shih-Chi Chao
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Mei-Fang Chou
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
| | - Shu-Fu Huang
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
| | - Niann-Tzyy Dai
- Department of Surgery, Division of Plastic and Reconstructive Surgery, Tri-Service General Hospital, Taipei, Taiwan
| | - Gwo-Jang Wu
- Department of Obstetrics and Gynecology, Tri-Service General Hospital, Taipei, Taiwan
| | - Chien-Sung Tsai
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
- Department of Pharmacology, National Defense Medical Center, Taipei, Taiwan
- Institute of Pharmacy, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Shih-Hurng Loh
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Department of Pharmacy Practice, Tri-Service General Hospital, Taipei, Taiwan
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Ting Tsai
- Department of Surgery, Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| |
Collapse
|
30
|
Transport properties in CFTR-/- knockout piglets suggest normal airway surface liquid pH and enhanced amiloride-sensitive Na + absorption. Pflugers Arch 2020; 472:1507-1519. [PMID: 32712714 PMCID: PMC7476968 DOI: 10.1007/s00424-020-02440-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 07/12/2020] [Accepted: 07/17/2020] [Indexed: 02/07/2023]
Abstract
Previous analysis of CFTR-knockout (CFTR-/-) in piglets has provided important insights into the pathology of cystic fibrosis. However, controversies exist as to the true contribution of CFTR to the pH balance in airways and intestine. We therefore compared ion transport properties in newborn wild-type (CFTR+/+) and CFTR-knockout (CFTR-/- piglets). Tracheas of CFTR-/- piglets demonstrated typical cartilage malformations and muscle cell bundles. CFTR-/- airway epithelial cells showed enhanced lipid peroxidation, suggesting inflammation early in life. CFTR was mainly expressed in airway submucosal glands and was absent in lungs of CFTR-/- piglets, while expression of TMEM16A was uncompromised. mRNA levels for TMEM16A, TMEM16F, and αβγENaC were unchanged in CFTR-/- airways, while mRNA for SLC26A9 appeared reduced. CFTR was undetectable in epithelial cells of CFTR-/- airways and intestine. Small intestinal epithelium of CFTR-/- piglets showed mucus accumulation. Secretion of both electrolytes and mucus was activated by stimulation with prostaglandin E2 and ATP in the intestine of CFTR+/+, but not of CFTR-/- animals. pH was measured inside small bronchi using a pH microelectrode and revealed no difference between CFTR+/+ and CFTR-/- piglets. Intracellular pH in porcine airway epithelial cells revealed only a small contribution of CFTR to bicarbonate secretion, which was absent in cells from CFTR-/- piglets. In contrast to earlier reports, our data suggest a minor impact of CFTR on ASL pH. In contrast, enhanced amiloride-sensitive Na+ absorption may contribute to lung pathology in CFTR-/- piglets, along with a compromised CFTR- and TMEM16A-dependent Cl- transport.
Collapse
|
31
|
Mitri C, Xu Z, Bardin P, Corvol H, Touqui L, Tabary O. Novel Anti-Inflammatory Approaches for Cystic Fibrosis Lung Disease: Identification of Molecular Targets and Design of Innovative Therapies. Front Pharmacol 2020; 11:1096. [PMID: 32848733 PMCID: PMC7396676 DOI: 10.3389/fphar.2020.01096] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022] Open
Abstract
Cystic fibrosis (CF) is the most common genetic disorder among Caucasians, estimated to affect more than 70,000 people in the world. Severe and persistent bronchial inflammation and chronic bacterial infection, along with airway mucus obstruction, are hallmarks of CF lung disease and participate in its progression. Anti-inflammatory therapies are, therefore, of particular interest for CF lung disease. Furthermore, a better understanding of the molecular mechanisms involved in airway infection and inflammation in CF has led to the development of new therapeutic approaches that are currently under evaluation by clinical trials. These new strategies dedicated to CF inflammation are designed to treat different dysregulated aspects such as oxidative stress, cytokine secretion, and the targeting of dysregulated pathways. In this review, we summarize the current understanding of the cellular and molecular mechanisms that contribute to abnormal lung inflammation in CF, as well as the new anti-inflammatory strategies proposed to CF patients by exploring novel molecular targets and novel drug approaches.
Collapse
Affiliation(s)
- Christie Mitri
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Zhengzhong Xu
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France.,Yangzhou University, Yangzhou, China
| | - Pauline Bardin
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| | - Harriet Corvol
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France.,Département de Pédiatrie Respiratoire, Hôpital Trousseau, AP-HP, Paris, France
| | - Lhousseine Touqui
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France.,Equipe Mucoviscidose et Bronchopathies Chroniques, Département Santé Globale, Institut Pasteur, Paris, France
| | - Olivier Tabary
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, Paris, France
| |
Collapse
|
32
|
Becskeházi E, Korsós MM, Erőss B, Hegyi P, Venglovecz V. OEsophageal Ion Transport Mechanisms and Significance Under Pathological Conditions. Front Physiol 2020; 11:855. [PMID: 32765303 PMCID: PMC7379034 DOI: 10.3389/fphys.2020.00855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/25/2020] [Indexed: 12/20/2022] Open
Abstract
Ion transporters play an important role in several physiological functions, such as cell volume regulation, pH homeostasis and secretion. In the oesophagus, ion transport proteins are part of the epithelial resistance, a mechanism which protects the oesophagus against reflux-induced damage. A change in the function or expression of ion transporters has significance in the development or neoplastic progression of Barrett’s oesophagus (BO). In this review, we discuss the physiological and pathophysiological roles of ion transporters in the oesophagus, highlighting transport proteins which serve as therapeutic targets or prognostic markers in eosinophilic oesophagitis, BO and esophageal cancer. We believe that this review highlights important relationships which might contribute to a better understanding of the pathomechanisms of esophageal diseases.
Collapse
Affiliation(s)
- Eszter Becskeházi
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | | | - Bálint Erőss
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary
| | - Péter Hegyi
- Institute for Translational Medicine, Szentágothai Research Centre, Medical School, University of Pécs, Pécs, Hungary.,Division of Gastroenterology, First Department of Medicine, Medical School, University of Pécs, Pécs, Hungary.,First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Viktória Venglovecz
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| |
Collapse
|
33
|
Shin DH, Kim M, Kim Y, Jun I, Jung J, Nam JH, Cheng MH, Lee MG. Bicarbonate permeation through anion channels: its role in health and disease. Pflugers Arch 2020; 472:1003-1018. [PMID: 32621085 DOI: 10.1007/s00424-020-02425-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/19/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
Many anion channels, frequently referred as Cl- channels, are permeable to different anions in addition to Cl-. As the second-most abundant anion in the human body, HCO3- permeation via anion channels has many important physiological roles. In addition to its classical role as an intracellular pH regulator, HCO3- also controls the activity and stability of dissolved proteins in bodily fluids such as saliva, pancreatic juice, intestinal fluid, and airway surface liquid. Moreover, HCO3- permeation through these channels affects membrane potentials that are the driving forces for transmembrane transport of solutes and water in epithelia and affect neuronal excitability in nervous tissue. Consequently, aberrant HCO3- transport via anion channels causes a number of human diseases in respiratory, gastrointestinal, genitourinary, and neuronal systems. Notably, recent studies have shown that the HCO3- permeabilities of several anion channels are not fixed and can be altered by cellular stimuli, findings which may have both physiological and pathophysiological significance. In this review, we summarize recent progress in understanding the molecular mechanisms and the physiological roles of HCO3- permeation through anion channels. We hope that the present discussions can stimulate further research into this very important topic, which will provide the basis for human disorders associated with aberrant HCO3- transport.
Collapse
Affiliation(s)
- Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Minjae Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Ikhyun Jun
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jinsei Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Kyungju, 780-714, Republic of Korea
| | - Mary Hongying Cheng
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea.
| |
Collapse
|
34
|
The Role of MicroRNA in the Airway Surface Liquid Homeostasis. Int J Mol Sci 2020; 21:ijms21113848. [PMID: 32481719 PMCID: PMC7312818 DOI: 10.3390/ijms21113848] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/24/2020] [Accepted: 05/25/2020] [Indexed: 02/06/2023] Open
Abstract
Mucociliary clearance, mediated by a coordinated function of cilia bathing in the airway surface liquid (ASL) on the surface of airway epithelium, protects the host from inhaled pathogens and is an essential component of the innate immunity. ASL is composed of the superficial mucus layer and the deeper periciliary liquid. Ion channels, transporters, and pumps coordinate the transcellular and paracellular movement of ions and water to maintain the ASL volume and mucus hydration. microRNA (miRNA) is a class of non-coding, short single-stranded RNA regulating gene expression by post-transcriptional mechanisms. miRNAs have been increasingly recognized as essential regulators of ion channels and transporters responsible for ASL homeostasis. miRNAs also influence the airway host defense. We summarize the most up-to-date information on the role of miRNAs in ASL homeostasis and host-pathogen interactions in the airway and discuss concepts for miRNA-directed therapy.
Collapse
|
35
|
Rehman T, Thornell IM, Pezzulo AA, Thurman AL, Romano Ibarra GS, Karp PH, Tan P, Duffey ME, Welsh MJ. TNFα and IL-17 alkalinize airway surface liquid through CFTR and pendrin. Am J Physiol Cell Physiol 2020; 319:C331-C344. [PMID: 32432926 PMCID: PMC7500220 DOI: 10.1152/ajpcell.00112.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The pH of airway surface liquid (ASL) is a key factor that determines respiratory host defense; ASL acidification impairs and alkalinization enhances key defense mechanisms. Under healthy conditions, airway epithelia secrete base ([Formula: see text]) and acid (H+) to control ASL pH (pHASL). Neutrophil-predominant inflammation is a hallmark of several airway diseases, and TNFα and IL-17 are key drivers. However, how these cytokines perturb pHASL regulation is uncertain. In primary cultures of differentiated human airway epithelia, TNFα decreased and IL-17 did not change pHASL. However, the combination (TNFα+IL-17) markedly increased pHASL by increasing [Formula: see text] secretion. TNFα+IL-17 increased expression and function of two apical [Formula: see text] transporters, CFTR anion channels and pendrin Cl-/[Formula: see text] exchangers. Both were required for maximal alkalinization. TNFα+IL-17 induced pendrin expression primarily in secretory cells where it was coexpressed with CFTR. Interestingly, significant pendrin expression was not detected in CFTR-rich ionocytes. These results indicate that TNFα+IL-17 stimulate [Formula: see text] secretion via CFTR and pendrin to alkalinize ASL, which may represent an important defense mechanism in inflamed airways.
Collapse
Affiliation(s)
- Tayyab Rehman
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Ian M Thornell
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Alejandro A Pezzulo
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Andrew L Thurman
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Guillermo S Romano Ibarra
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Philip H Karp
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Ping Tan
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Michael E Duffey
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Michael J Welsh
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| |
Collapse
|
36
|
Measurement of Multi Ion Transport through Human Bronchial Epithelial Cell Line Provides an Insight into the Mechanism of Defective Water Transport in Cystic Fibrosis. MEMBRANES 2020; 10:membranes10030043. [PMID: 32178452 PMCID: PMC7142439 DOI: 10.3390/membranes10030043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/28/2022]
Abstract
We measured concentration changes of sodium, potassium, chloride ions, pH and the transepithelial potential difference by means of ion-selective electrodes, which were placed on both sides of a human bronchial epithelial 16HBE14σ cell line grown on a porous support in the presence of ion channel blockers. We found that, in the isosmotic transepithelial concentration gradient of either sodium or chloride ions, there is an electroneutral transport of the isosmotic solution of sodium chloride in both directions across the cell monolayer. The transepithelial potential difference is below 3 mV. Potassium and pH change plays a minor role in ion transport. Based on our measurements, we hypothesize that in a healthy bronchial epithelium, there is a dynamic balance between water absorption and secretion. Water absorption is caused by the action of two exchangers, Na/H and Cl/HCO3, secreting weakly dissociated carbonic acid in exchange for well dissociated NaCl and water. The water secretion phase is triggered by an apical low volume-dependent factor opening the Cystic Fibrosis Transmembrane Regulator CFTR channel and secreting anions that are accompanied by paracellular sodium and water transport.
Collapse
|
37
|
Liu CZ, Li FY, Lv XF, Ma MM, Li XY, Lin CX, Wang GL, Guan YY. Endophilin A2 regulates calcium-activated chloride channel activity via selective autophagy-mediated TMEM16A degradation. Acta Pharmacol Sin 2020; 41:208-217. [PMID: 31484993 PMCID: PMC7470808 DOI: 10.1038/s41401-019-0298-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023] Open
Abstract
TMEM16A Ca2+-activated chloride channel (CaCC) plays an essential role in vascular homeostasis. In this study we investigated the molecular mechanisms underlying downregulation of TMEM16A CaCC activity during hypertension. In cultured basilar artery smooth muscle cells (BASMCs) isolated from 2k2c renohypertesive rats, treatment with angiotensin II (0.125-1 μM) dose-dependently increased endophilin A2 levels and decreased TMEM16A expression. Similar phenomenon was observed in basilar artery isolated from 2k2c rats. We then used whole-cell recording to examine whether endophilin A2 could regulate TMEM16A CaCC activity in BASMCs and found that knockdown of endophilin A2 significantly enhanced CaCC activity, whereas overexpression of endophilin A2 produced the opposite effect. Overexpression of endophilin A2 did not affect the TMEM16A mRNA level, but markedly decreased TMEM16A protein level in BASMCs by inducing ubiquitination and autophagy of TMEM16A. Ubiquitin-binding receptor p62 (SQSTM1) could bind to ubiquitinated TMEM16A and resulted in a process of TMEM16A proteolysis in autophagosome/lysosome. These data provide new insights into the regulation of TMEM16A CaCC activity by endophilin A2 in BASMCs, which partly explains the mechanism of angiotensin-II-induced TMEM16A inhibition during hypertension-induced vascular remodeling.
Collapse
Affiliation(s)
- Can-Zhao Liu
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.
| | - Fei-Ya Li
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Xiao-Fei Lv
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Ming-Ming Ma
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Xiang-Yu Li
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Cai-Xia Lin
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Guan-Lei Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Yong-Yuan Guan
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.
| |
Collapse
|
38
|
Simões FB, Quaresma MC, Clarke LA, Silva IA, Pankonien I, Railean V, Kmit A, Amaral MD. TMEM16A chloride channel does not drive mucus production. Life Sci Alliance 2019; 2:2/6/e201900462. [PMID: 31732694 PMCID: PMC6859295 DOI: 10.26508/lsa.201900462] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/29/2019] [Accepted: 11/06/2019] [Indexed: 01/07/2023] Open
Abstract
Despite being essential for airway hydration, TMEM16A is not required for mucus (MUC5AC) production. Cell proliferation is the main driver for TMEM16A up-regulation during inflammation. Airway mucus obstruction is the main cause of morbidity in cystic fibrosis, a disease caused by mutations in the CFTR Cl− channel. Activation of non-CFTR Cl− channels such as TMEM16A can likely compensate for defective CFTR. However, TMEM16A was recently described as a key driver in mucus production/secretion. Here, we have examined whether indeed there is a causal relationship between TMEM16A and MUC5AC production, the main component of respiratory mucus. Our data show that TMEM16A and MUC5AC are inversely correlated during differentiation of human airway cells. Furthermore, we show for the first time that the IL-4–induced TMEM16A up-regulation is proliferation-dependent, which is supported by the correlation found between TMEM16A and Ki-67 proliferation marker during wound healing. Consistently, the notch signaling activator DLL4 increases MUC5AC levels without inducing changes neither in TMEM16A nor in Ki-67 expression. Moreover, TMEM16A inhibition decreased airway surface liquid height. Altogether, our findings demonstrate that up-regulation of TMEM16A and MUC5AC is only circumstantial under cell proliferation, but with no causal relationship between them. Thus, although essential for airway hydration, TMEM16A is not required for MUC5AC production.
Collapse
Affiliation(s)
- Filipa B Simões
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Margarida C Quaresma
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Luka A Clarke
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Iris Al Silva
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Ines Pankonien
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Violeta Railean
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Arthur Kmit
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| | - Margarida D Amaral
- University of Lisboa, Faculty of Sciences, BioISI-Biosystems & Integrative Sciences Institute, Lisboa, Portugal
| |
Collapse
|
39
|
Kim Y, Jun I, Shin DH, Yoon JG, Piao H, Jung J, Park HW, Cheng MH, Bahar I, Whitcomb DC, Lee MG. Regulation of CFTR Bicarbonate Channel Activity by WNK1: Implications for Pancreatitis and CFTR-Related Disorders. Cell Mol Gastroenterol Hepatol 2019; 9:79-103. [PMID: 31561038 PMCID: PMC6889609 DOI: 10.1016/j.jcmgh.2019.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/28/2022]
Abstract
BACKGRAOUD & AIMS Aberrant epithelial bicarbonate (HCO3-) secretion caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is associated with several diseases including cystic fibrosis and pancreatitis. Dynamically regulated ion channel activity and anion selectivity of CFTR by kinases sensitive to intracellular chloride concentration ([Cl-]i) play an important role in epithelial HCO3- secretion. However, the molecular mechanisms of how [Cl-]i-dependent mechanisms regulate CFTR are unknown. METHODS We examined the mechanisms of the CFTR HCO3- channel regulation by [Cl-]i-sensitive kinases using an integrated electrophysiological, molecular, and computational approach including whole-cell, outside-out, and inside-out patch clamp recordings and molecular dissection of WNK1 and CFTR proteins. In addition, we analyzed the effects of pancreatitis-causing CFTR mutations on the WNK1-mediated regulation of CFTR. RESULTS Among the WNK1, SPAK, and OSR1 kinases that constitute a [Cl-]i-sensitive kinase cascade, the expression of WNK1 alone was sufficient to increase the CFTR bicarbonate permeability (PHCO3/PCl) and conductance (GHCO3) in patch clamp recordings. Molecular dissection of the WNK1 domains revealed that the WNK1 kinase domain is responsible for CFTR PHCO3/PCl regulation by direct association with CFTR, while the surrounding N-terminal regions mediate the [Cl-]i-sensitivity of WNK1. Furthermore, the pancreatitis-causing R74Q and R75Q mutations in the elbow helix 1 of CFTR hampered WNK1-CFTR physical associations and reduced WNK1-mediated CFTR PHCO3/PCl regulation. CONCLUSION The CFTR HCO3- channel activity is regulated by [Cl-]i and a WNK1-dependent mechanism. Our results provide new insights into the regulation of the ion selectivity of CFTR and the pathogenesis of CFTR-related disorders.
Collapse
Affiliation(s)
- Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Ikhyun Jun
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea,Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
| | - Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jihoon G. Yoon
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - He Piao
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jinsei Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea,Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
| | - Hyun Woo Park
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Mary Hongying Cheng
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ivet Bahar
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David C. Whitcomb
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea,Correspondence Address correspondence to: Min Goo Lee, Department of Pharmacology, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul 03722, Korea. fax: +82 2 313 1894.
| |
Collapse
|
40
|
Crottès D, Jan LY. The multifaceted role of TMEM16A in cancer. Cell Calcium 2019; 82:102050. [PMID: 31279157 PMCID: PMC6711484 DOI: 10.1016/j.ceca.2019.06.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/13/2019] [Accepted: 06/13/2019] [Indexed: 12/30/2022]
Abstract
The calcium-activated chloride channel TMEM16A is intimately linked to cancers. Over decades, TMEM16A over-expression and contribution to prognosis have been widely studied for multiple cancers strengthening the idea that TMEM16A could be a valuable biomarker and a promising therapeutic target. Surprisingly, from the survey of the literature, it appears that TMEM16A has been involved in multiple cancer-related functions and a large number of molecular targets of TMEM16A have been proposed. Thus, TMEM16A appears to be an ion channel with a multifaceted role in cancers. In this review, we summarize the latest development regarding TMEM16A contribution to cancers. We will survey TMEM16A contribution in cancer prognosis, the origins of its over-expression in cancer cells, the multiple biological functions and molecular pathways regulated by TMEM16A. Then, we will consider the question regarding the molecular mechanism of TMEM16A in cancers and the possible basis for the multifaceted role of TMEM16A in cancers.
Collapse
Affiliation(s)
- David Crottès
- Departments of Physiology, Biochemistry, and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Lily Yeh Jan
- Departments of Physiology, Biochemistry, and Biophysics, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, 94143, USA.
| |
Collapse
|
41
|
Le SC, Jia Z, Chen J, Yang H. Molecular basis of PIP 2-dependent regulation of the Ca 2+-activated chloride channel TMEM16A. Nat Commun 2019; 10:3769. [PMID: 31434906 PMCID: PMC6704070 DOI: 10.1038/s41467-019-11784-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/02/2019] [Indexed: 11/20/2022] Open
Abstract
The calcium-activated chloride channel (CaCC) TMEM16A plays crucial roles in regulating neuronal excitability, smooth muscle contraction, fluid secretion and gut motility. While opening of TMEM16A requires binding of intracellular Ca2+, prolonged Ca2+-dependent activation results in channel desensitization or rundown, the mechanism of which is unclear. Here we show that phosphatidylinositol (4,5)-bisphosphate (PIP2) regulates TMEM16A channel activation and desensitization via binding to a putative binding site at the cytosolic interface of transmembrane segments (TMs) 3-5. We further demonstrate that the ion-conducting pore of TMEM16A is constituted of two functionally distinct modules: a Ca2+-binding module formed by TMs 6-8 and a PIP2-binding regulatory module formed by TMs 3-5, which mediate channel activation and desensitization, respectively. PIP2 dissociation from the regulatory module results in ion-conducting pore collapse and subsequent channel desensitization. Our findings thus provide key insights into the mechanistic understanding of TMEM16 channel gating and lipid-dependent regulation.
Collapse
Affiliation(s)
- Son C Le
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Zhiguang Jia
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA.
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.
| |
Collapse
|
42
|
Cleaved Cochlin Sequesters Pseudomonas aeruginosa and Activates Innate Immunity in the Inner Ear. Cell Host Microbe 2019; 25:513-525.e6. [DOI: 10.1016/j.chom.2019.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/14/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023]
|
43
|
Benedetto R, Cabrita I, Schreiber R, Kunzelmann K. TMEM16A is indispensable for basal mucus secretion in airways and intestine. FASEB J 2018; 33:4502-4512. [PMID: 30586313 DOI: 10.1096/fj.201801333rrr] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Transmembrane member 16A (TMEM16A) is the Ca2+-activated chloride channel in airways and intestine. It has been associated with goblet cell metaplasia, as expression of TMEM16A is strongly up-regulated in cystic fibrosis and asthma during mucus hypersecretion. However, the possible role of TMEM16A for mucus production or mucus secretion remains obscure, and whether TMEM16A controls the function of intestinal goblet cells is entirely unknown. Basal mucus secretion in lungs occurs through low levels of ATP in the airway surface liquid. Here, we report for the first time that TMEM16A is essential for basal secretion of mucus in airways and intestine. Airway-ciliated and intestinal epithelial-specific knockout of TMEM16A ( TMEM16Aflox/floxFoxJ1, TMEM16Aflox/floxVil1) leads to accumulation of mucus in airway club (Clara) cells and intestinal goblet cells, respectively. Acute ATP-induced mucus secretion by airway club cells is inhibited when TMEM16A is knocked out in ciliated cells, possibly as a result of compromised release of prosecretory cytokines. Knockdown or inhibition of TMEM16A in human Calu3 airway epithelial cells indicates compromised IL-8 release. In intestinal goblet cells lacking expression of TMEM16A, mucus accumulates as a result of compromised ATP-induced secretion. In contrast, cholinergic mucus secretion by compound exocytosis is independent of TMEM16A. The data demonstrate a previously unrecognized role of TMEM16A for membrane exocytosis and describe a novel, ATP-driven pathway for intestinal mucus secretion. We conclude that ATP-dependent mucus secretion in both airways and intestine requires TMEM16A. The present results may form the basis for a novel, therapeutic approach for the treatment of mucus hypersecretion in inflammatory airway and intestinal disease.-Benedetto, R., Cabrita, I., Schreiber, R., Kunzelmann, K. TMEM16A is indispensable for basal mucus secretion in airways and intestine.
Collapse
Affiliation(s)
- Roberta Benedetto
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - Inês Cabrita
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| |
Collapse
|
44
|
Madácsy T, Pallagi P, Maleth J. Cystic Fibrosis of the Pancreas: The Role of CFTR Channel in the Regulation of Intracellular Ca 2+ Signaling and Mitochondrial Function in the Exocrine Pancreas. Front Physiol 2018; 9:1585. [PMID: 30618777 PMCID: PMC6306458 DOI: 10.3389/fphys.2018.01585] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/23/2018] [Indexed: 12/26/2022] Open
Abstract
Cystic fibrosis (CF) is the most common genetic disorder that causes a significant damage in secretory epithelial cells due to the defective ion flux across the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel. Pancreas is one of the organs most frequently damaged by the disease leading to pancreatic insufficiency, abdominal pain and an increased risk of acute pancreatitis in CF patients causing a significant decrease in the quality of life. CFTR plays a central role in the pancreatic ductal secretory functions by carrying Cl- and HCO3 - ions across the apical membrane. Therefore pathophysiological studies in CF mostly focused on the effects of impaired ion secretion by pancreatic ductal epithelial cells leading to exocrine pancreatic damage. However, several studies indicated that CFTR has a central role in the regulation of intracellular signaling processes and is now more widely considered as a signaling hub in epithelial cells. In contrast, elevated intracellular Ca2+ level was observed in the lack of functional CFTR in different cell types including airway epithelial cells. In addition, impaired CFTR expression has been correlated with damaged mitochondrial function in epithelial cells. These alterations of intracellular signaling in CF are not well characterized in the exocrine pancreas yet. Therefore in this review we would like to summarize the complex role of CFTR in the exocrine pancreas with a special focus on the intracellular signaling and mitochondrial function.
Collapse
Affiliation(s)
- Tamara Madácsy
- First Department of Medicine, University of Szeged, Szeged, Hungary.,HAS-USZ Momentum Epithel Cell Signalling and Secretion Research Group, Szeged, Hungary
| | - Petra Pallagi
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Jozsef Maleth
- First Department of Medicine, University of Szeged, Szeged, Hungary.,HAS-USZ Momentum Epithel Cell Signalling and Secretion Research Group, Szeged, Hungary.,Department of Public Health, University of Szeged, Szeged, Hungary
| |
Collapse
|
45
|
Choi J, Jang Y, Kim H, Wee J, Cho S, Son WS, Kim SM, Yang YD. Functional roles of glutamic acid E143 and E705 residues in the N-terminus and transmembrane domain 7 of Anoctamin 1 in calcium and noxious heat sensing. BMB Rep 2018; 51:236-241. [PMID: 29335069 PMCID: PMC5988578 DOI: 10.5483/bmbrep.2018.51.5.199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Indexed: 01/12/2023] Open
Abstract
Anoctamin 1 (ANO1) is an anion channel that is activated by changes in cytosolic Ca2+ concentration and noxious heat. Although the critical roles of ANO1 have been elucidated in various cell types, the control of its gating mechanisms by Ca2+ and heat remain more elusive. To investigate critical amino acid residues for modulation of Ca2+ and heat sensing, we constructed a randomized mutant library for ANO1. Among 695 random mutants, reduced Ca2+ sensitivity was observed in two mutants (mutant 84 and 87). Consequently, the E143A mutant showed reduced sensitivity to Ca2+ but not to high temperatures, whereas the E705V mutant exhibited reduced sensitivity to both Ca2+ and noxious heat. These results suggest that the glutamic acids (E) at 143 and 705 residues in ANO1 are critical for modulation of Ca2+ and/or heat responses. Furthermore, these findings help to provide a better understanding of the Ca2+-mediated activation and heat-sensing mechanism of ANO1.
Collapse
Affiliation(s)
- Jonghyun Choi
- College of Pharmacy, CHA University, Sungnam 13488, Korea
| | - Yongwoo Jang
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA 02478, USA
| | - Haedong Kim
- College of Pharmacy, CHA University, Sungnam 13488, Korea
| | - Jungwon Wee
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea
| | - Sinyoung Cho
- College of Pharmacy, CHA University, Sungnam 13488, Korea
| | - Woo Sung Son
- College of Pharmacy, CHA University, Sungnam 13488, Korea
| | - Sung Min Kim
- Department of Physical Education, College of Performing Arts and Sport, Hanyang University, Seoul 04763; Department of Active Aging Industry, Graduate School, Hanyang University, Seoul 04763, Korea
| | - Young Duk Yang
- College of Pharmacy, CHA University, Sungnam 13488, Korea
| |
Collapse
|
46
|
Webster MJ, Tarran R. Slippery When Wet: Airway Surface Liquid Homeostasis and Mucus Hydration. CURRENT TOPICS IN MEMBRANES 2018; 81:293-335. [PMID: 30243435 DOI: 10.1016/bs.ctm.2018.08.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The ability to regulate cell volume is crucial for normal physiology; equally the regulation of extracellular fluid homeostasis is of great importance. Alteration of normal extracellular fluid homeostasis contributes to the development of several diseases including cystic fibrosis. With regard to the airway surface liquid (ASL), which lies apically on top of airway epithelia, ion content, pH, mucin and protein abundance must be tightly regulated. Furthermore, airway epithelia must be able to switch from an absorptive to a secretory state as required. A heterogeneous population of airway epithelial cells regulate ASL solute and solvent composition, and directly secrete large mucin molecules, antimicrobials, proteases and soluble mediators into the airway lumen. This review focuses on how epithelial ion transport influences ASL hydration and ASL pH, with a specific focus on the roles of anion and cation channels and exchangers. The role of ions and pH in mucin expansion is also addressed. With regard to fluid volume regulation, we discuss the roles of nucleotides, adenosine and the short palate lung and nasal epithelial clone 1 (SPLUNC1) as soluble ASL mediators. Together, these mechanisms directly influence ciliary beating and in turn mucociliary clearance to maintain sterility and to detoxify the airways. Whilst all of these components are regulated in normal airways, defective ion transport and/or mucin secretion proves detrimental to lung homeostasis as such we address how defective ion and fluid transport, and a loss of homeostatic mechanisms, contributes to the development of pathophysiologies associated with cystic fibrosis.
Collapse
Affiliation(s)
- Megan J Webster
- Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Robert Tarran
- Marsico Lung Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Cell Biology & Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| |
Collapse
|
47
|
Strug LJ, Stephenson AL, Panjwani N, Harris A. Recent advances in developing therapeutics for cystic fibrosis. Hum Mol Genet 2018; 27:R173-R186. [PMID: 30060192 PMCID: PMC6061831 DOI: 10.1093/hmg/ddy188] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 12/23/2022] Open
Abstract
Despite hope that a cure was imminent when the causative gene was cloned nearly 30 years ago, cystic fibrosis (CF [MIM: 219700]) remains a life-shortening disease affecting more than 70 000 individuals worldwide. However, within the last 6 years the Food and Drug Administration's approval of Ivacaftor, the first drug that corrects the defective cystic fibrosis transmembrane conductance regulator protein [CFTR (MIM: 602421)] in patients with the G551D mutation, marks a watershed in the development of novel therapeutics for this devastating disease. Here we review recent progress in diverse research areas, which all focus on curing CF at the genetic, biochemical or physiological level. In the near future it seems probable that development of mutation-specific therapies will be the focus, since it is unlikely that any one approach will be efficient in correcting the more than 2000 disease-associated variants. We discuss the new drugs and combinations of drugs that either enhance delivery of misfolded CFTR protein to the cell membrane, where it functions as an ion channel, or that activate channel opening. Next we consider approaches to correct the causative genetic lesion at the DNA or RNA level, through repressing stop mutations and nonsense-mediated decay, modulating splice mutations, fixing errors by gene editing or using novel routes to gene replacement. Finally, we explore how modifier genes, loci elsewhere in the genome that modify CF disease severity, may be used to restore a normal phenotype. Progress in all of these areas has been dramatic, generating enthusiasm that CF may soon become a broadly treatable disease.
Collapse
Affiliation(s)
- Lisa J Strug
- Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, ON, Canada
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Anne L Stephenson
- Department of Respirology, Adult Cystic Fibrosis Program, St. Michael’s Hospital, Toronto, ON, Canada
- Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada
| | - Naim Panjwani
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| |
Collapse
|
48
|
Massip-Copiz MM, Santa-Coloma TA. Extracellular pH and lung infections in cystic fibrosis. Eur J Cell Biol 2018; 97:402-410. [PMID: 29933921 DOI: 10.1016/j.ejcb.2018.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/01/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by CFTR mutations. It is characterized by high NaCl concentration in sweat and the production of a thick and sticky mucus, occluding secretory ducts, intestine and airways, accompanied by chronic inflammation and infections of the lungs. This causes a progressive and lethal decline in lung function. Therefore, finding the mechanisms driving the high susceptibility to lung infections has been a key issue. For decades the prevalent hypothesis was that a reduced airway surface liquid (ASL) volume and composition, and the consequent increased mucus concentration (dehydration), create an environment favoring infections. However, a few years ago, in a pig model of CF, the Na+/K+ concentrations and the ASL volume were found intact. Immediately a different hypothesis arose, postulating a reduced ASL pH as the cause for the increased susceptibility to infections, due to a diminished bicarbonate secretion through CFTR. Noteworthy, a recent report found normal ASL pH values in CF children and in cultured primary airway cells, challenging the ASL pH hypothesis. On the other hand, recent evidences revitalized the hypothesis of a reduced ASL secretion. Thus, the role of the ASL pH in the CF is still a controversial matter. In this review we discuss the basis that sustain the role of CFTR in modulating the extracellular pH, and the recent results sustaining the different points of view. Finding the mechanisms of CFTR signaling that determine the susceptibility to infections is crucial to understand the pathophysiology of CF and related lung diseases.
Collapse
Affiliation(s)
- María Macarena Massip-Copiz
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED UCA-CONICET), The National Scientific and Technical Research Council (CONICET), and School of Medical Sciences, The Pontifical Catholic University of Argentina (UCA), Buenos Aires, Argentina
| | - Tomás Antonio Santa-Coloma
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED UCA-CONICET), The National Scientific and Technical Research Council (CONICET), and School of Medical Sciences, The Pontifical Catholic University of Argentina (UCA), Buenos Aires, Argentina.
| |
Collapse
|
49
|
Luo Y, Yu X, Ma C, Luo J, Yang W. Identification of a Novel EF-Loop in the N-terminus of TRPM2 Channel Involved in Calcium Sensitivity. Front Pharmacol 2018; 9:581. [PMID: 29915540 PMCID: PMC5994415 DOI: 10.3389/fphar.2018.00581] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/15/2018] [Indexed: 01/10/2023] Open
Abstract
As an oxidative stress sensor, transient receptor potential melastatin 2 (TRPM2) channel is involved in many physiological and pathological processes including warmth sensing, ischemia injury, inflammatory diseases and diabetes. Intracellular calcium is critical for TRPM2 channel activation and the IQ-like motif in the N-terminus has been shown to be important by mediating calmodulin binding. Sequence analysis predicted two potential EF-loops in the N-terminus of TRPM2. Site-directed mutagenesis combining with functional assay showed that substitution with alanine of several residues, most of which are conserved in the typical EF-loop, including D267, D278, D288, and E298 dramatically reduced TRPM2 channel currents. By further changing the charges or side chain length of these conserved residues, our results indicate that the negative charge of D267 and the side chain length of D278 are critical for calcium-induced TRPM2 channel activation. G272I mutation also dramatically reduced the channel currents, suggesting that this site is critical for calcium-induced TRPM2 channel activation. Furthermore, D267A mutant dramatically reduced the currents induced by calcium alone compared with that by ADPR, indicating that D267 residue in D267–D278 motif is the most important site for calcium sensitivity of TRPM2. In addition, inside-out recordings showed that mutations at D267, G272, D278, and E298 had no effect on single-channel conductance. Taken together, our data indicate that D267–D278 motif in the N-terminus as a novel EF-loop is critical for calcium-induced TRPM2 channel activation.
Collapse
Affiliation(s)
- Yuhuan Luo
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiafei Yu
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Cheng Ma
- Co-facility Center, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhong Luo
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Yang
- Department of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
50
|
Rahmati N, Hoebeek FE, Peter S, De Zeeuw CI. Chloride Homeostasis in Neurons With Special Emphasis on the Olivocerebellar System: Differential Roles for Transporters and Channels. Front Cell Neurosci 2018; 12:101. [PMID: 29765304 PMCID: PMC5938380 DOI: 10.3389/fncel.2018.00101] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 03/28/2018] [Indexed: 12/14/2022] Open
Abstract
The intraneuronal ionic composition is an important determinant of brain functioning. There is growing evidence that aberrant homeostasis of the intracellular concentration of Cl- ([Cl-]i) evokes, in addition to that of Na+ and Ca2+, robust impairments of neuronal excitability and neurotransmission and thereby neurological conditions. More specifically, understanding the mechanisms underlying regulation of [Cl-]i is crucial for deciphering the variability in GABAergic and glycinergic signaling of neurons, in both health and disease. The homeostatic level of [Cl-]i is determined by various regulatory mechanisms, including those mediated by plasma membrane Cl- channels and transporters. This review focuses on the latest advances in identification, regulation and characterization of Cl- channels and transporters that modulate neuronal excitability and cell volume. By putting special emphasis on neurons of the olivocerebellar system, we establish that Cl- channels and transporters play an indispensable role in determining their [Cl-]i and thereby their function in sensorimotor coordination.
Collapse
Affiliation(s)
- Negah Rahmati
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
| | - Freek E. Hoebeek
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- NIDOD Institute, Wilhelmina Children's Hospital, University Medical Center Utrecht and Brain Center Rudolf Magnus, Utrecht, Netherlands
| | - Saša Peter
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
| | - Chris I. De Zeeuw
- Department of Neuroscience, Erasmus Medical Center, Rotterdam, Netherlands
- Netherlands Institute for Neuroscience, Royal Dutch Academy for Arts and Sciences, Amsterdam, Netherlands
| |
Collapse
|