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Ramananda Y, Naren AP, Arora K. Functional Consequences of CFTR Interactions in Cystic Fibrosis. Int J Mol Sci 2024; 25:3384. [PMID: 38542363 PMCID: PMC10970640 DOI: 10.3390/ijms25063384] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/09/2024] [Accepted: 03/12/2024] [Indexed: 09/01/2024] Open
Abstract
Cystic fibrosis (CF) is a fatal autosomal recessive disorder caused by the loss of function mutations within a single gene for the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). CFTR is a chloride channel that regulates ion and fluid transport across various epithelia. The discovery of CFTR as the CF gene and its cloning in 1989, coupled with extensive research that went into the understanding of the underlying biological mechanisms of CF, have led to the development of revolutionary therapies in CF that we see today. The highly effective modulator therapies have increased the survival rates of CF patients and shifted the epidemiological landscape and disease prognosis. However, the differential effect of modulators among CF patients and the presence of non-responders and ineligible patients underscore the need to develop specialized and customized therapies for a significant number of patients. Recent advances in the understanding of the CFTR structure, its expression, and defined cellular compositions will aid in developing more precise therapies. As the lifespan of CF patients continues to increase, it is becoming critical to clinically address the extra-pulmonary manifestations of CF disease to improve the quality of life of the patients. In-depth analysis of the molecular signature of different CF organs at the transcriptional and post-transcriptional levels is rapidly advancing and will help address the etiological causes and variability of CF among patients and develop precision medicine in CF. In this review, we will provide an overview of CF disease, leading to the discovery and characterization of CFTR and the development of CFTR modulators. The later sections of the review will delve into the key findings derived from single-molecule and single-cell-level analyses of CFTR, followed by an exploration of disease-relevant protein complexes of CFTR that may ultimately define the etiological course of CF disease.
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Affiliation(s)
- Yashaswini Ramananda
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Anjaparavanda P. Naren
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Kavisha Arora
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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2
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Bolger GB. Therapeutic Targets and Precision Medicine in COPD: Inflammation, Ion Channels, Both, or Neither? Int J Mol Sci 2023; 24:17363. [PMID: 38139192 PMCID: PMC10744217 DOI: 10.3390/ijms242417363] [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: 11/13/2023] [Revised: 12/04/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
The development of a wider range of therapeutic options is a key objective in drug discovery for chronic obstructive pulmonary disease (COPD). Fundamental advances in lung biology have the potential to greatly expand the number of therapeutic targets in COPD. The recently reported successful Phase 3 clinical trial of the first biologic agent for COPD, the monoclonal antibody dupilumab, adds additional support to the importance of targeting inflammatory pathways in COPD. However, numerous other cellular mechanisms are important targets in COPD therapeutics, including airway remodeling, the CFTR ion channel, and mucociliary function. Some of these emerging targets can be exploited by the expanded use of existing COPD drugs, such as roflumilast, while targeting others will require the development of novel molecular entities. The identification of additional therapeutic targets and agents has the potential to greatly expand the value of using clinical and biomarker data to classify COPD into specific subsets, each of which can be predictive of an enhanced response to specific subset(s) of targeted therapies. The author reviews established and emerging drug targets in COPD and uses this as a framework to define a novel classification of COPD based on therapeutic targets. This novel classification has the potential to enhance precision medicine in COPD patient care and to accelerate clinical trials and pre-clinical drug discovery efforts.
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Affiliation(s)
- Graeme B Bolger
- BZI Pharma LLC, 1500 1st Ave N., Unit 36, Birmingham, AL 35203-1872, USA
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3
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Dobi D, Loberto N, Bassi R, Pistocchi A, Lunghi G, Tamanini A, Aureli M. Cross-talk between CFTR and sphingolipids in cystic fibrosis. FEBS Open Bio 2023; 13:1601-1614. [PMID: 37315117 PMCID: PMC10476574 DOI: 10.1002/2211-5463.13660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 06/16/2023] Open
Abstract
Cystic fibrosis (CF) is the most common inherited, life-limiting disorder in Caucasian populations. It is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), which lead to an impairment of protein expression and/or function. CFTR is a chloride/bicarbonate channel expressed at the apical surface of epithelial cells of different organs. Nowadays, more than 2100 CFTR genetic variants have been described, but not all of them cause CF. However, around 80-85% of the patients worldwide are characterized by the presence, at least in one allele, of the mutation F508del. CFTR mutations cause aberrant hydration and secretion of mucus in hollow organs. In the lungs, this condition favors bacterial colonization, allowing the development of chronic infections that lead to the onset of the CF lung disease, which is the main cause of death in patients. In recent years, evidence has reported that CFTR loss of function is responsible for alterations in a particular class of bioactive lipids, called sphingolipids (SL). SL are ubiquitously present in eukaryotic cells and are mainly asymmetrically located within the external leaflet of the plasma membrane, where they organize specific platforms capable of segregating a selected number of proteins. CFTR is associated with these platforms that are fundamental for its functioning. Considering the importance of SL in CFTR homeostasis, we attempt here to provide a critical overview of the literature to determine the role of these lipids in channel stability and activity, and whether their modulation in CF could be a target for new therapeutic approaches.
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Affiliation(s)
- Dorina Dobi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Nicoletta Loberto
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Rosaria Bassi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Anna Pistocchi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Giulia Lunghi
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
| | - Anna Tamanini
- Section of Clinical Biochemistry, Department of Neurosciences, Biomedicine and MovementUniversity of VeronaItaly
| | - Massimo Aureli
- Department of Medical Biotechnology and Translational MedicineUniversity of MilanItaly
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Murabito A, Bhatt J, Ghigo A. It Takes Two to Tango! Protein-Protein Interactions behind cAMP-Mediated CFTR Regulation. Int J Mol Sci 2023; 24:10538. [PMID: 37445715 DOI: 10.3390/ijms241310538] [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: 05/17/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Over the last fifteen years, with the approval of the first molecular treatments, a breakthrough era has begun for patients with cystic fibrosis (CF), the rare genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR). These molecules, known as CFTR modulators, have led to unprecedented improvements in the lung function and quality of life of most CF patients. However, the efficacy of these drugs is still suboptimal, and the clinical response is highly variable even among individuals bearing the same mutation. Furthermore, not all patients carrying rare CFTR mutations are eligible for CFTR modulator therapies, indicating the need for alternative and/or add-on therapeutic approaches. Because the second messenger 3',5'-cyclic adenosine monophosphate (cAMP) represents the primary trigger for CFTR activation and a major regulator of different steps of the life cycle of the channel, there is growing interest in devising ways to fine-tune the cAMP signaling pathway for therapeutic purposes. This review article summarizes current knowledge regarding the role of cAMP signalosomes, i.e., multiprotein complexes bringing together key enzymes of the cAMP pathway, in the regulation of CFTR function, and discusses how modulating this signaling cascade could be leveraged for therapeutic intervention in CF.
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Affiliation(s)
- Alessandra Murabito
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center "Guido Tarone", University of Torino, 10126 Torino, Italy
| | - Janki Bhatt
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center "Guido Tarone", University of Torino, 10126 Torino, Italy
- Kither Biotech S.r.l., 10126 Torino, Italy
| | - Alessandra Ghigo
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center "Guido Tarone", University of Torino, 10126 Torino, Italy
- Kither Biotech S.r.l., 10126 Torino, Italy
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Cartwright IM, Colgan SP. The hypoxic tissue microenvironment as a driver of mucosal inflammatory resolution. Front Immunol 2023; 14:1124774. [PMID: 36742292 PMCID: PMC9890178 DOI: 10.3389/fimmu.2023.1124774] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 01/06/2023] [Indexed: 01/19/2023] Open
Abstract
On the backdrop of all acute inflammatory processes lies the activation of the resolution response. Recent years have witnessed an emerging interest in defining molecular factors that influence the resolution of inflammation. A keystone feature of the mucosal inflammatory microenvironment is hypoxia. The gastrointestinal tract, particularly the colon, exists in a state of physiological hypoxia and during active inflammation, this hypoxic state is enhanced as a result of infiltrating leukocyte oxygen consumption and the activation of oxygen consuming enzymes. Most evidence suggests that mucosal hypoxia promotes the active resolution of inflammation through a variety of mechanisms, including extracellular acidification, purine biosynthesis/salvage, the generation of specialized pro-resolving lipid mediators (ie. resolvins) and altered chemokine/cytokine expression. It is now appreciated that infiltrating innate immune cells (neutrophils, eosinophils, macrophages) have an important role in molding the tissue microenvironment to program an active resolution response. Structural or functional dysregulation of this inflammatory microenvironment can result in the loss of tissue homeostasis and ultimately progression toward chronicity. In this review, we will discuss how inflammatory hypoxia drives mucosal inflammatory resolution and its impact on other microenvironmental factors that influence resolution.
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Affiliation(s)
- Ian M. Cartwright
- Division of Gastroenterology and Hepatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, CO, United States
- Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States
| | - Sean P. Colgan
- Division of Gastroenterology and Hepatology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, United States
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, CO, United States
- Rocky Mountain Regional Veterans Affairs Medical Center, Aurora, CO, United States
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Thiopurines impair the apical plasma membrane expression of CFTR in pancreatic ductal cells via RAC1 inhibition. Cell Mol Life Sci 2023; 80:31. [PMID: 36609875 PMCID: PMC9825359 DOI: 10.1007/s00018-022-04662-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/15/2022] [Accepted: 12/02/2022] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND AIMS Thiopurine-induced acute pancreatitis (TIP) is one of the most common adverse events among inflammatory bowel disease patients treated with azathioprine (AZA), representing a significant clinical burden. Previous studies focused on immune-mediated processes, however, the exact pathomechanism of TIP is essentially unclear. METHODS To model TIP in vivo, we triggered cerulein-induced experimental pancreatitis in mice receiving a daily oral dose of 1.5 mg/kg AZA. Also, freshly isolated mouse pancreatic cells were exposed to AZA ex vivo, and acinar cell viability, ductal and acinar Ca2+ signaling, ductal Cl- and HCO3- secretion, as well as cystic fibrosis transmembrane conductance regulator (CFTR) expression were assessed using microscopy techniques. Ras-related C3 botulinum toxin substrate (RAC1) activity was measured with a G-LISA assay. Super-resolution microscopy was used to determine protein colocalization. RESULTS We demonstrated that AZA treatment increases tissue damage in the early phase of cerulein-induced pancreatitis in vivo. Also, both per os and ex vivo AZA exposure impaired pancreatic fluid and ductal HCO3- and Cl- secretion, but did not affect acinar cells. Furthermore, ex vivo AZA exposure also inhibited RAC1 activity in ductal cells leading to decreased co-localization of CFTR and the anchor protein ezrin, resulting in impaired plasma membrane localization of CFTR. CONCLUSIONS AZA impaired the ductal HCO3- and Cl- secretion through the inhibition of RAC1 activity leading to diminished ezrin-CFTR interaction and disturbed apical plasma membrane expression of CFTR. We report a novel direct toxic effect of AZA on pancreatic ductal cells and suggest that the restoration of ductal function might help to prevent TIP in the future.
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Zhao S, Luo J, Hu J, Wang H, Zhao N, Cao M, Zhang C, Hu R, Liu L. Role of Ezrin in Asthma-Related Airway Inflammation and Remodeling. Mediators Inflamm 2022; 2022:6255012. [PMID: 36530558 PMCID: PMC9750775 DOI: 10.1155/2022/6255012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 08/13/2023] Open
Abstract
Ezrin is an actin binding protein connecting the cell membrane and the cytoskeleton, which is crucial to maintaining cell morphology, intercellular adhesion, and cytoskeleton remodeling. Asthma involves dysfunction of inflammatory cells, cytokines, and airway structural cells. Recent studies have shown that ezrin, whose function is affected by extensive phosphorylation and protein interactions, is closely associated with asthma, may be a therapeutic target for asthma treatment. In this review, we summarize studies on ezrin and discuss its role in asthma-related airway inflammation and remodeling.
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Affiliation(s)
- Shumei Zhao
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Jiaqi Luo
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Jun Hu
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Hesheng Wang
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Ningwei Zhao
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Shimadzu Biomedical Research Laboratory, Shanghai 200233, China
| | - Meng Cao
- Nanjing University of Chinese Medicine, Nanjing 210029, China
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine Nanjing University of Chinese Medicine, Nanjing 210028, China
| | - Cong Zhang
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Rongkui Hu
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
| | - Lanying Liu
- Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing 210029, China
- Nanjing University of Chinese Medicine, Nanjing 210029, China
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8
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Kim H, Kim H, Nguyen LT, Ha T, Lim S, Kim K, Kim SH, Han K, Hyeon SJ, Ryu H, Park YS, Kim SH, Kim IB, Hong GS, Lee SE, Choi Y, Cohen LB, Oh U. Amplification of olfactory signals by Anoctamin 9 is important for mammalian olfaction. Prog Neurobiol 2022; 219:102369. [PMID: 36330924 DOI: 10.1016/j.pneurobio.2022.102369] [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: 05/21/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Sensing smells of foods, prey, or predators determines animal survival. Olfactory sensory neurons in the olfactory epithelium (OE) detect odorants, where cAMP and Ca2+ play a significant role in transducing odorant inputs to electrical activity. Here we show Anoctamin 9, a cation channel activated by cAMP/PKA pathway, is expressed in the OE and amplifies olfactory signals. Ano9-deficient mice had reduced olfactory behavioral sensitivity, electro-olfactogram signals, and neural activity in the olfactory bulb. In line with the difference in olfaction between birds and other vertebrates, chick ANO9 failed to respond to odorants, whereas chick CNGA2, a major transduction channel, showed greater responses to cAMP. Thus, we concluded that the signal amplification by ANO9 is important for mammalian olfactory transduction.
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Affiliation(s)
- Hyungsup Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyesu Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea
| | - Luan Thien Nguyen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Taewoong Ha
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Sujin Lim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyungmin Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Soon Ho Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Kyungreem Han
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Jae Hyeon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hoon Ryu
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yong Soo Park
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Sang Hyun Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - In-Beom Kim
- Department of Anatomy, Catholic Institute for Applied Anatomy, College of Medicine, Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Gyu-Sang Hong
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Seung Eun Lee
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Yunsook Choi
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Lawrence B Cohen
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
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Kawaguchi K, Asano S. Pathophysiological Roles of Actin-Binding Scaffold Protein, Ezrin. Int J Mol Sci 2022; 23:ijms23063246. [PMID: 35328667 PMCID: PMC8952289 DOI: 10.3390/ijms23063246] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023] Open
Abstract
Ezrin is one of the members of the ezrin/radixin/moesin (ERM) family of proteins. It was originally discovered as an actin-binding protein in the microvilli structure about forty years ago. Since then, it has been revealed as a key protein with functions in a variety of fields including cell migration, survival, and signal transduction, as well as functioning as a structural component. Ezrin acts as a cross-linker of membrane proteins or phospholipids in the plasma membrane and the actin cytoskeleton. It also functions as a platform for signaling molecules at the cell surface. Moreover, ezrin is regarded as an important target protein in cancer diagnosis and therapy because it is a key protein involved in cancer progression and metastasis, and its high expression is linked to poor survival in many cancers. Small molecule inhibitors of ezrin have been developed and investigated as candidate molecules that suppress cancer metastasis. Here, we wish to comprehensively review the roles of ezrin from the pathophysiological points of view.
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Sholokh A, Klussmann E. Local cyclic adenosine monophosphate signalling cascades-Roles and targets in chronic kidney disease. Acta Physiol (Oxf) 2021; 232:e13641. [PMID: 33660401 DOI: 10.1111/apha.13641] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 12/20/2022]
Abstract
The molecular mechanisms underlying chronic kidney disease (CKD) are poorly understood and treatment options are limited, a situation underpinning the need for elucidating the causative molecular mechanisms and for identifying innovative treatment options. It is emerging that cyclic 3',5'-adenosine monophosphate (cAMP) signalling occurs in defined cellular compartments within nanometre dimensions in processes whose dysregulation is associated with CKD. cAMP compartmentalization is tightly controlled by a specific set of proteins, including A-kinase anchoring proteins (AKAPs) and phosphodiesterases (PDEs). AKAPs such as AKAP18, AKAP220, AKAP-Lbc and STUB1, and PDE4 coordinate arginine-vasopressin (AVP)-induced water reabsorption by collecting duct principal cells. However, hyperactivation of the AVP system is associated with kidney damage and CKD. Podocyte injury involves aberrant AKAP signalling. cAMP signalling in immune cells can be local and slow the progression of inflammatory processes typical for CKD. A major risk factor of CKD is hypertension. cAMP directs the release of the blood pressure regulator, renin, from juxtaglomerular cells, and plays a role in Na+ reabsorption through ENaC, NKCC2 and NCC in the kidney. Mutations in the cAMP hydrolysing PDE3A that cause lowering of cAMP lead to hypertension. Another major risk factor of CKD is diabetes mellitus. AKAP18 and AKAP150 and several PDEs are involved in insulin release. Despite the increasing amount of data, an understanding of functions of compartmentalized cAMP signalling with relevance for CKD is fragmentary. Uncovering functions will improve the understanding of physiological processes and identification of disease-relevant aberrations may guide towards new therapeutic concepts for the treatment of CKD.
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Affiliation(s)
- Anastasiia Sholokh
- Max‐Delbrück‐Center for Molecular Medicine (MDC) Helmholtz Association Berlin Germany
| | - Enno Klussmann
- Max‐Delbrück‐Center for Molecular Medicine (MDC) Helmholtz Association Berlin Germany
- DZHK (German Centre for Cardiovascular Research) Berlin Germany
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11
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Pathophysiology of Lung Disease and Wound Repair in Cystic Fibrosis. PATHOPHYSIOLOGY 2021; 28:155-188. [PMID: 35366275 PMCID: PMC8830450 DOI: 10.3390/pathophysiology28010011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/08/2021] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive, life-threatening condition affecting many organs and tissues, the lung disease being the chief cause of morbidity and mortality. Mutations affecting the CF Transmembrane Conductance Regulator (CFTR) gene determine the expression of a dysfunctional protein that, in turn, triggers a pathophysiological cascade, leading to airway epithelium injury and remodeling. In vitro and in vivo studies point to a dysregulated regeneration and wound repair in CF airways, to be traced back to epithelial CFTR lack/dysfunction. Subsequent altered ion/fluid fluxes and/or signaling result in reduced cell migration and proliferation. Furthermore, the epithelial-mesenchymal transition appears to be partially triggered in CF, contributing to wound closure alteration. Finally, we pose our attention to diverse approaches to tackle this defect, discussing the therapeutic role of protease inhibitors, CFTR modulators and mesenchymal stem cells. Although the pathophysiology of wound repair in CF has been disclosed in some mechanisms, further studies are warranted to understand the cellular and molecular events in more details and to better address therapeutic interventions.
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12
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Role of calcineurin biosignaling in cell secretion and the possible regulatory mechanisms. Saudi J Biol Sci 2021; 28:116-124. [PMID: 33424288 PMCID: PMC7783665 DOI: 10.1016/j.sjbs.2020.08.042] [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: 07/05/2020] [Revised: 08/02/2020] [Accepted: 08/30/2020] [Indexed: 11/22/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP) and calcium ions (Ca2+) are two chemical molecules that play a central role in the stimulus-dependent secretion processes within cells. Ca2+ acts as the basal signaling molecule responsible to initiate cell secretion. cAMP primarily acts as an intracellular second messenger in a myriad of cellular processes by activating cAMP-dependent protein kinases through association with such kinases in order to mediate post-translational phosphorylation of those protein targets. Put succinctly, both Ca2+ and cAMP act by associating or activating other proteins to ensure successful secretion. Calcineurin is one such protein regulated by Ca2+; its action depends on the intracellular levels of Ca2+. Being a phosphatase, calcineurin dephosphorylate and other proteins, as is the case with most other phosphatases, such as protein phosphatase 2A (PP2A), PP2C, and protein phosphatase-1 (PP1), will likely be activated by phosphorylation. Via this process, calcineurin is able to affect different intracellular signaling with clinical importance, some of which has been the basis for development of different calcineurin inhibitors. In this review, the cAMP-dependent calcineurin bio-signaling, protein-protein interactions and their physiological implications as well as regulatory signaling within the context of cellular secretion are explored.
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13
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions. SIGNIFICANCE STATEMENT: cAMP mediates the intracellular response to multiple hormones and neurotransmitters. Signal fidelity and accurate coordination of a plethora of different cellular functions is achieved via organization of multiprotein signalosomes and cAMP compartmentalization in subcellular nanodomains. Defining the organization and regulation of subcellular cAMP nanocompartments is necessary if we want to understand the complex functional ramifications of pharmacological treatments that target G protein-coupled receptors and for generating a blueprint that can be used to develop precision medicine interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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14
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Lee H, Yu D, Park JS, Lee H, Kim J, Kim HL, Koo S, Lee J, Lee S, Ko Y. Prominin-1-Radixin axis controls hepatic gluconeogenesis by regulating PKA activity. EMBO Rep 2020; 21:e49416. [PMID: 33030802 PMCID: PMC7645247 DOI: 10.15252/embr.201949416] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 08/31/2020] [Accepted: 09/10/2020] [Indexed: 12/18/2022] Open
Abstract
Prominin-1 (Prom1) is a major cell surface marker of cancer stem cells, but its physiological functions in the liver have not been elucidated. We analyzed the levels of mRNA transcripts in serum-starved primary WT (Prom1+/+ ) and KO (Prom1-/- ) mouse hepatocytes using RNA sequencing (RNA-seq) data, and found that CREB target genes were downregulated. This initial observation led us to determine that Prom1 deficiency inhibited cAMP response element-binding protein (CREB) activation and gluconeogenesis, but not cyclic AMP (cAMP) accumulation, in glucagon-, epinephrine-, or forskolin-treated liver tissues and primary hepatocytes, and mitigated glucagon-induced hyperglycemia. Because Prom1 interacted with radixin, Prom1 deficiency prevented radixin from localizing to the plasma membrane. Moreover, systemic adenoviral knockdown of radixin inhibited CREB activation and gluconeogenesis in glucagon-treated liver tissues and primary hepatocytes, and mitigated glucagon-elicited hyperglycemia. Based on these results, we conclude that Prom1 regulates hepatic PKA signaling via radixin functioning as an A kinase-anchored protein (AKAP).
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Affiliation(s)
- Hyun Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Dong‐Min Yu
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jun Sub Park
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Hwayeon Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jun‐Seok Kim
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Hong Lim Kim
- Laboratory of Electron MicroscopeIntegrative Research Support CenterCollege of MedicineThe Catholic University of KoreaSeoulKorea
| | - Seung‐Hoi Koo
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jae‐Seon Lee
- Department of Molecular MedicineInha University College of MedicineIncheonKorea
- Hypoxia‐related Disease Research CenterInha University College of MedicineIncheonKorea
| | - Sungsoo Lee
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Young‐Gyu Ko
- Tunneling Nanotube Research CenterKorea UniversitySeoulKorea
- Division of Life SciencesKorea UniversitySeoulKorea
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15
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Wang Y, Zhao J, Cai Y, Ballard HJ. Cystic fibrosis transmembrane conductance regulator-dependent bicarbonate entry controls rat cardiomyocyte ATP release via pannexin1 through mitochondrial signalling and caspase activation. Acta Physiol (Oxf) 2020; 230:e13495. [PMID: 32386453 DOI: 10.1111/apha.13495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 04/27/2020] [Accepted: 05/01/2020] [Indexed: 12/20/2022]
Abstract
AIM Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in the heart, but its function there is unclear. CFTR regulates an ATP release pore in many tissues, but the identity and regulatory mechanism of the pore are unknown. We investigated the role of CFTR in ATP release from primary cardiomyocytes and ventricular wall in vivo. METHODS Proteins involved in the signalling pathway for ATP release during simulated ischaemia (lactic acid treatment) were investigated using inhibitors and siRNA; colocalization was identified by coimmunofluorescence and proximity ligation assays; changes in near-membrane pH and calcium were identified with total internal reflection microscopy; in vivo ATP release was investigated using interstitial microdialysis of rat heart. RESULTS Lactic acid-induced CFTR-dependent ATP release from cultured cardiomyocytes and left ventricle in vivo. Lactic acid entry elevated near-membrane calcium, which involved Na/H- and Na/Ca-exchangers colocalized with CFTR. Calcium entry-induced CFTR activation, which involved cAMP, protein kinase A, FAK, Pyk2 and Src. Removal of extracellular bicarbonate abolished cardiomyocyte ATP release induced by lactic acid or CFTR activators. Bicarbonate stimulated cytochrome c expression, cytochrome c release and ATP release from isolated cardiomyocyte mitochondria. Pannexin 1 (Panx1) colocalized with CFTR. Lactic acid increased cardiomyocyte caspase activity: caspase inhibitors or Panx1 siRNA abolished cardiomyocyte ATP release, while pannexin inhibition abolished cardiac ATP release in vivo. CONCLUSION During simulated ischaemia, CFTR-dependent bicarbonate entry stimulated ATP and cytochrome c release from mitochondria; in the cytoplasm, cytochrome c-activated caspase 3, which in turn activated Panx1, and ATP was released through the opened Panx1 channel.
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Affiliation(s)
- Yongshun Wang
- School of Biomedical Sciences The University of Hong Kong Pokfulam Hong Kong
| | - Junjun Zhao
- School of Biomedical Sciences The University of Hong Kong Pokfulam Hong Kong
| | - Yin Cai
- Department of Anaesthesiology The University of Hong Kong Pokfulam Hong Kong
| | - Heather J. Ballard
- School of Biomedical Sciences The University of Hong Kong Pokfulam Hong Kong
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16
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Simple binding of protein kinase A prior to phosphorylation allows CFTR anion channels to be opened by nucleotides. Proc Natl Acad Sci U S A 2020; 117:21740-21746. [PMID: 32817533 PMCID: PMC7474675 DOI: 10.1073/pnas.2007910117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) anion channel is essential for epithelial salt-water balance. CFTR mutations cause cystic fibrosis, a lethal incurable disease. In cells CFTR is activated through the cAMP signaling pathway, overstimulation of which during cholera leads to CFTR-mediated intestinal salt-water loss. Channel activation is achieved by phosphorylation of its regulatory (R) domain by cAMP-dependent protein kinase catalytic subunit (PKA). Here we show using two independent approaches--an ATP analog that can drive CFTR channel gating but is unsuitable for phosphotransfer by PKA, and CFTR mutants lacking phosphorylatable serines--that PKA efficiently opens CFTR channels through simple binding, under conditions that preclude phosphorylation. Unlike when phosphorylation happens, CFTR activation by PKA binding is completely reversible. Thus, PKA binding promotes release of the unphosphorylated R domain from its inhibitory position, causing full channel activation, whereas phosphorylation serves only to maintain channel activity beyond termination of the PKA signal. The results suggest two levels of CFTR regulation in cells: irreversible through phosphorylation, and reversible through R-domain binding to PKA--and possibly also to other members of a large network of proteins known to interact with the channel.
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17
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GM1 as Adjuvant of Innovative Therapies for Cystic Fibrosis Disease. Int J Mol Sci 2020; 21:ijms21124486. [PMID: 32599772 PMCID: PMC7350007 DOI: 10.3390/ijms21124486] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 01/26/2023] Open
Abstract
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is expressed at the apical plasma membrane (PM) of different epithelial cells. The most common mutation responsible for the onset of cystic fibrosis (CF), F508del, inhibits the biosynthesis and transport of the protein at PM, and also presents gating and stability defects of the membrane anion channel upon its rescue by the use of correctors and potentiators. This prompted a multiple drug strategy for F508delCFTR aimed simultaneously at its rescue, functional potentiation and PM stabilization. Since ganglioside GM1 is involved in the functional stabilization of transmembrane proteins, we investigated its role as an adjuvant to increase the effectiveness of CFTR modulators. According to our results, we found that GM1 resides in the same PM microenvironment as CFTR. In CF cells, the expression of the mutated channel is accompanied by a decrease in the PM GM1 content. Interestingly, by the exogenous administration of GM1, it becomes a component of the PM, reducing the destabilizing effect of the potentiator VX-770 on rescued CFTR protein expression/function and improving its stabilization. This evidence could represent a starting point for developing innovative therapeutic strategies based on the co-administration of GM1, correctors and potentiators, with the aim of improving F508del CFTR function.
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18
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Sussman CR, Wang X, Chebib FT, Torres VE. Modulation of polycystic kidney disease by G-protein coupled receptors and cyclic AMP signaling. Cell Signal 2020; 72:109649. [PMID: 32335259 DOI: 10.1016/j.cellsig.2020.109649] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/11/2022]
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a systemic disorder associated with polycystic liver disease (PLD) and other extrarenal manifestations, the most common monogenic cause of end-stage kidney disease, and a major burden for public health. Many studies have shown that alterations in G-protein and cAMP signaling play a central role in its pathogenesis. As for many other diseases (35% of all approved drugs target G-protein coupled receptors (GPCRs) or proteins functioning upstream or downstream from GPCRs), treatments targeting GPCR have shown effectiveness in slowing the rate of progression of ADPKD. Tolvaptan, a vasopressin V2 receptor antagonist is the first drug approved by regulatory agencies to treat rapidly progressive ADPKD. Long-acting somatostatin analogs have also been effective in slowing the rates of growth of polycystic kidneys and liver. Although no treatment has so far been able to prevent the development or stop the progression of the disease, these encouraging advances point to G-protein and cAMP signaling as a promising avenue of investigation that may lead to more effective and safe treatments. This will require a better understanding of the relevant GPCRs, G-proteins, cAMP effectors, and of the enzymes and A-kinase anchoring proteins controlling the compartmentalization of cAMP signaling. The purpose of this review is to provide an overview of general GPCR signaling; the function of polycystin-1 (PC1) as a putative atypical adhesion GPCR (aGPCR); the roles of PC1, polycystin-2 (PC2) and the PC1-PC2 complex in the regulation of calcium and cAMP signaling; the cross-talk of calcium and cAMP signaling in PKD; and GPCRs, adenylyl cyclases, cyclic nucleotide phosphodiesterases, and protein kinase A as therapeutic targets in ADPKD.
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Affiliation(s)
- Caroline R Sussman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Xiaofang Wang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Fouad T Chebib
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America
| | - Vicente E Torres
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States of America.
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19
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Bieth E, Hamdi SM, Mieusset R. Genetics of the congenital absence of the vas deferens. Hum Genet 2020; 140:59-76. [PMID: 32025909 PMCID: PMC7864840 DOI: 10.1007/s00439-020-02122-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/28/2020] [Indexed: 01/19/2023]
Abstract
Congenital absence of the vas deferens (CAVD) may have various clinical presentations depending on whether it is bilateral (CBAVD) or unilateral (CUAVD), complete or partial, and associated or not with other abnormalities of the male urogenital tract. CBAVD is usually discovered in adult men either during the systematic assessment of cystic fibrosis or other CFTR-related conditions, or during the exploration of isolated infertility with obstructive azoospermia. The prevalence of CAVDs in men is reported to be approximately 0.1%. However, this figure is probably underestimated, because unilateral forms of CAVD in asymptomatic fertile men are not usually diagnosed. The diagnosis of CAVDs is based on clinical, ultrasound, and sperm examinations. The majority of subjects with CAVD carry at least one cystic fibrosis-causing mutation that warrants CFTR testing and in case of a positive result, genetic counseling prior to conception. Approximately 2% of the cases of CAVD are hemizygous for a loss-of-function mutation in the ADGRG2 gene that may cause a familial form of X-linked infertility. However, despite this recent finding, 10–20% of CBAVDs and 60–70% of CUAVDs remain without a genetic diagnosis. An important proportion of these unexplained CAVDs coexist with a solitary kidney suggesting an early organogenesis disorder (Wolffian duct), unlike CAVDs related to CFTR or ADGRG2 mutations, which might be the result of progressive degeneration that begins later in fetal life and probably continues after birth. How the dysfunction of CFTR, ADGRG2, or other genes such as SLC29A3 leads to this involution is the subject of various pathophysiological hypotheses that are discussed in this review.
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Affiliation(s)
- Eric Bieth
- Service de Génétique Médicale, Hôpital Purpan, CHU, 31059, Toulouse, France.
| | - Safouane M Hamdi
- Service de Biochimie, Institut Fédératif de Biologie, CHU, 31059, Toulouse, France.,EA3694 (Groupe de Recherche en Fertilité Humaine), Université Toulouse III, 31059, Toulouse, France
| | - Roger Mieusset
- EA3694 (Groupe de Recherche en Fertilité Humaine), Université Toulouse III, 31059, Toulouse, France.,Département d'Andrologie (Groupe Activité Médecine de la Reproduction), CHU, 31059, Toulouse, France
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20
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Martin ER, Barbieri A, Ford RC, Robinson RC. In vivo crystals reveal critical features of the interaction between cystic fibrosis transmembrane conductance regulator (CFTR) and the PDZ2 domain of Na +/H + exchange cofactor NHERF1. J Biol Chem 2020; 295:4464-4476. [PMID: 32014995 DOI: 10.1074/jbc.ra119.012015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/17/2020] [Indexed: 12/23/2022] Open
Abstract
Crystallization of recombinant proteins has been fundamental to our understanding of protein function, dysfunction, and molecular recognition. However, this information has often been gleaned under extremely nonphysiological protein, salt, and H+ concentrations. Here, we describe the development of a robust Inka1-Box (iBox)-PAK4cat system that spontaneously crystallizes in several mammalian cell types. The semi-quantitative assay described here allows the measurement of in vivo protein-protein interactions using a novel GFP-linked reporter system that produces fluorescent readouts from protein crystals. We combined this assay with in vitro X-ray crystallography and molecular dynamics studies to characterize the molecular determinants of the interaction between the PDZ2 domain of Na+/H+ exchange regulatory cofactor NHE-RF1 (NHERF1) and cystic fibrosis transmembrane conductance regulator (CFTR), a protein complex pertinent to the genetic disease cystic fibrosis. These experiments revealed the crystal structure of the extended PDZ domain of NHERF1 and indicated, contrary to what has been previously reported, that residue selection at positions -1 and -3 of the PDZ-binding motif influences the affinity and specificity of the NHERF1 PDZ2-CFTR interaction. Our results suggest that this system could be utilized to screen additional protein-protein interactions, provided they can be accommodated within the spacious iBox-PAK4cat lattice.
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Affiliation(s)
- Eleanor R Martin
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Manchester, M13 9PL, United Kingdom.,Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis 138673, Singapore
| | - Alessandro Barbieri
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Manchester, M13 9PL, United Kingdom.,Bioinformatics Institute (BII), A*STAR (Agency for Science, Technology and Research), Biopolis 138671, Singapore
| | - Robert C Ford
- School of Biological Sciences, Faculty of Biology Medicine and Health, Michael Smith Building, The University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Robert C Robinson
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis 138673, Singapore .,School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand.,Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
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21
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Wu Q, Eickelberg O. Ezrin in Asthma: A First Step to Early Biomarkers of Airway Epithelial Dysfunction. Am J Respir Crit Care Med 2019; 199:408-410. [PMID: 30383410 DOI: 10.1164/rccm.201810-1964ed] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Qun Wu
- 1 Division of Pulmonary Sciences and Critical Care Medicine University of Colorado Anschutz Medical Campus Denver, Colorado
| | - Oliver Eickelberg
- 1 Division of Pulmonary Sciences and Critical Care Medicine University of Colorado Anschutz Medical Campus Denver, Colorado
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22
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Muimo R, Alothaid HM, Mehta A. NM23 proteins: innocent bystanders or local energy boosters for CFTR? J Transl Med 2018; 98:272-282. [PMID: 29251738 DOI: 10.1038/labinvest.2017.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 08/25/2017] [Accepted: 09/12/2017] [Indexed: 12/17/2022] Open
Abstract
NM23 proteins NDPK-A and -B bind to the cystic fibrosis (CF) protein CFTR in different ways from kinases such as PKA, CK2 and AMPK or linkers to cell calcium such as calmodulin and annexins. NDPK-A (not -B) interacts with CFTR through reciprocal AMPK binding/control, whereas NDPK-B (not -A) binds directly to CFTR. NDPK-B can activate G proteins without ligand-receptor coupling, so perhaps NDPK-B's binding influences energy supply local to a nucleotide-binding site (NBD1) needed for CFTR to function. Curiously, CFTR (ABC-C7) is a member of the ATP-binding cassette (ABC) protein family that does not obey 'clan rules'; CFTR channels anions and is not a pump, regulates disparate processes, is itself regulated by multiple means and is so pleiotropic that it acts as a hub that orchestrates calcium signaling through its consorts such as calmodulin/annexins. Furthermore, its multiple partners make CFTR dance to different tunes in different cellular and subcellular locations as it recycles from the plasma membrane to endosomes. CFTR function in airway apical membranes is inhibited by smoking which has been dubbed 'acquired CF'. CFTR alone among family members possesses a trap for other proteins that it unfurls as a 'fish-net' and which bears consensus phosphorylation sites for many protein kinases, with PKA being the most canonical. Recently, the site of CFTR's commonest mutation has been proposed as a knock-in mutant that alters allosteric control of kinase CK2 by log orders of activity towards calmodulin and other substrates after CFTR fragmentation. This link from CK2 to calmodulin that binds the R region invokes molecular paths that control lumen formation, which is incomplete in the tracheas of some CF-affected babies. Thus, we are poised to understand the many roles of NDPK-A and -B in CFTR function and, especially lumen formation, which is defective in the gut and lungs of many CF babies.
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Affiliation(s)
- Richmond Muimo
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, UK
| | - Hani Mm Alothaid
- Department of Infection, Immunity and Cardiovascular Disease, The Medical School, University of Sheffield, Sheffield, UK
| | - Anil Mehta
- Medical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
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23
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Lim SH, Legere EA, Snider J, Stagljar I. Recent Progress in CFTR Interactome Mapping and Its Importance for Cystic Fibrosis. Front Pharmacol 2018; 8:997. [PMID: 29403380 PMCID: PMC5785726 DOI: 10.3389/fphar.2017.00997] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/26/2017] [Indexed: 12/25/2022] Open
Abstract
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a chloride channel found in secretory epithelia with a plethora of known interacting proteins. Mutations in the CFTR gene cause cystic fibrosis (CF), a disease that leads to progressive respiratory illness and other complications of phenotypic variance resulting from perturbations of this protein interaction network. Studying the collection of CFTR interacting proteins and the differences between the interactomes of mutant and wild type CFTR provides insight into the molecular machinery of the disease and highlights possible therapeutic targets. This mini review focuses on functional genomics and proteomics approaches used for systematic, high-throughput identification of CFTR-interacting proteins to provide comprehensive insight into CFTR regulation and function.
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Affiliation(s)
- Sang Hyun Lim
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | | | - Jamie Snider
- Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Igor Stagljar
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
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24
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Therapeutic Approaches to Acquired Cystic Fibrosis Transmembrane Conductance Regulator Dysfunction in Chronic Bronchitis. Ann Am Thorac Soc 2018; 13 Suppl 2:S169-76. [PMID: 27115953 DOI: 10.1513/annalsats.201509-601kv] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Chronic obstructive pulmonary disease is a common cause of morbidity and a rising cause of mortality worldwide. Its rising impact indicates the ongoing unmet need for novel and effective therapies. Previous work has established a pathophysiological link between the chronic bronchitis phenotype of chronic obstructive pulmonary disease and cystic fibrosis as well as phenotypic similarities between these two airways diseases. An extensive body of evidence has established that cigarette smoke and its constituents contribute to acquired dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the airways, pointing to a mechanistic link with smoking-related and chronic bronchitis. Recent interest surrounding new drugs that target both mutant and wild-type CFTR channels has paved the way for a new treatment opportunity addressing the mucus defect in chronic bronchitis. We review the clinical and pathologic evidence for modulating CFTR to address acquired CFTR dysfunction and pragmatic issues surrounding clinical trials as well as a discussion of other ion channels that may represent alternative therapeutic targets.
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25
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Puglia M, Landi C, Gagliardi A, Breslin L, Armini A, Brunetti J, Pini A, Bianchi L, Bini L. The proteome speciation of an immortalized cystic fibrosis cell line: New perspectives on the pathophysiology of the disease. J Proteomics 2018; 170:28-42. [DOI: 10.1016/j.jprot.2017.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/01/2017] [Accepted: 09/25/2017] [Indexed: 01/04/2023]
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26
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Kawaguchi K, Yoshida S, Hatano R, Asano S. Pathophysiological Roles of Ezrin/Radixin/Moesin Proteins. Biol Pharm Bull 2017; 40:381-390. [PMID: 28381792 DOI: 10.1248/bpb.b16-01011] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ezrin/radixin/moesin (ERM) proteins function as general cross-linkers between plasma membrane proteins and the actin cytoskeleton and are involved in the functional expression of membrane proteins on the cell surface. They also integrate Rho guanosine 5'-triphosphatase (GTPase) signaling to regulate cytoskeletal organization by sequestering Rho-related proteins. They act as protein kinase A (PKA)-anchoring proteins and sequester PKA close to its target proteins for their effective phosphorylation and functional regulation. Therefore, ERM proteins seem to play important roles in the membrane transport of electrolytes by ion channels and transporters. In this review, we focus on the pathophysiological roles of ERM proteins in in vivo studies and introduce the phenotypes of their knockout and knockdown mice.
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Affiliation(s)
- Kotoku Kawaguchi
- Department of Molecular Physiology, College of Pharmaceutical Sciences, Ritsumeikan University
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27
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Aureli M, Schiumarini D, Loberto N, Bassi R, Tamanini A, Mancini G, Tironi M, Munari S, Cabrini G, Dechecchi MC, Sonnino S. Unravelling the role of sphingolipids in cystic fibrosis lung disease. Chem Phys Lipids 2016; 200:94-103. [DOI: 10.1016/j.chemphyslip.2016.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 12/13/2022]
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28
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Lasalvia M, Castellani S, D'Antonio P, Perna G, Carbone A, Colia AL, Maffione AB, Capozzi V, Conese M. Human airway epithelial cells investigated by atomic force microscopy: A hint to cystic fibrosis epithelial pathology. Exp Cell Res 2016; 348:46-55. [PMID: 27590528 DOI: 10.1016/j.yexcr.2016.08.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 08/17/2016] [Accepted: 08/29/2016] [Indexed: 01/01/2023]
Abstract
The pathophysiology of cystic fibrosis (CF) airway disease stems from mutations in the CF Transmembrane Conductance Regulator (CFTR) gene, leading to a chronic respiratory disease. Actin cytoskeleton is disorganized in CF airway epithelial cells, likely contributing to the CF-associated basic defects, i.e. defective chloride secretion and sodium/fluid hypersorption. In this work, we aimed to find whether this alteration could be pointed out by means of Atomic Force Microscopy (AFM) investigation, as roughness and Young's elastic module. Moreover, we also sought to determine whether disorganization of actin cytoskeleton is linked to hypersoption of apical fluid. Not only CFBE41o- (CFBE) cells, immortalized airway epithelial cells homozygous for the F508del CFTR allele, showed a different morphology in comparison with 16HBE14o- (16HBE) epithelial cells, wild-type for CFTR, but also they displayed a lack of stress fibers, suggestive of a disorganized actin cytoskeleton. AFM measurements showed that CFBE cells presented a higher membrane roughness and decreased rigidity as compared with 16HBE cells. CFBE overexpressing wtCFTR became more elongated than the parental CFBE cell line and presented actin stress fibers. CFBE cells absorbed more fluid from the apical compartment. Study of fluid absorption with the F-actin-depolymerizing agent Latrunculin B demonstrated that actin cytoskeletal disorganization increased fluid absorption, an effect observed at higher magnitude in 16HBE than in CFBE cells. For the first time, we demonstrate that actin cytoskeleton disorganization is reflected by AFM parameters in CF airway epithelial cells. Our data also strongly suggest that the lack of stress fibers is involved in at least one of the early step in CF pathophysiology at the levels of the airways, i.e. fluid hypersorption.
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Affiliation(s)
- Maria Lasalvia
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy; Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari, Italy
| | - Stefano Castellani
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Palma D'Antonio
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Giuseppe Perna
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy; Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari, Italy
| | - Annalucia Carbone
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Anna Laura Colia
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Angela Bruna Maffione
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy
| | - Vito Capozzi
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia, Italy; Istituto Nazionale di Fisica Nucleare, Sezione di Bari, Bari, Italy
| | - Massimo Conese
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy.
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Lobo MJ, Amaral MD, Zaccolo M, Farinha CM. EPAC1 activation by cAMP stabilizes CFTR at the membrane by promoting its interaction with NHERF1. J Cell Sci 2016; 129:2599-612. [PMID: 27206858 DOI: 10.1242/jcs.185629] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/17/2016] [Indexed: 01/14/2023] Open
Abstract
Cyclic AMP (cAMP) activates protein kinase A (PKA) but also the guanine nucleotide exchange factor 'exchange protein directly activated by cAMP' (EPAC1; also known as RAPGEF3). Although phosphorylation by PKA is known to regulate CFTR channel gating - the protein defective in cystic fibrosis - the contribution of EPAC1 to CFTR regulation remains largely undefined. Here, we demonstrate that in human airway epithelial cells, cAMP signaling through EPAC1 promotes CFTR stabilization at the plasma membrane by attenuating its endocytosis, independently of PKA activation. EPAC1 and CFTR colocalize and interact through protein adaptor NHERF1 (also known as SLC9A3R1). This interaction is promoted by EPAC1 activation, triggering its translocation to the plasma membrane and binding to NHERF1. Our findings identify a new CFTR-interacting protein and demonstrate that cAMP activates CFTR through two different but complementary pathways - the well-known PKA-dependent channel gating pathway and a new mechanism regulating endocytosis that involves EPAC1. The latter might constitute a novel therapeutic target for treatment of cystic fibrosis.
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Affiliation(s)
- Miguel J Lobo
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, Lisboa 1749-016, Portugal Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Margarida D Amaral
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, Lisboa 1749-016, Portugal
| | - Manuela Zaccolo
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Carlos M Farinha
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, Lisboa 1749-016, Portugal
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Abbattiscianni AC, Favia M, Mancini MT, Cardone RA, Guerra L, Monterisi S, Castellani S, Laselva O, Di Sole F, Conese M, Zaccolo M, Casavola V. Correctors of mutant CFTR enhance subcortical cAMP-PKA signaling through modulating ezrin phosphorylation and cytoskeleton organization. J Cell Sci 2016; 129:1128-40. [PMID: 26823603 DOI: 10.1242/jcs.177907] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 01/21/2016] [Indexed: 12/28/2022] Open
Abstract
The most common mutation of the cystic fibrosis transmembrane regulator (CFTR) gene, F508del, produces a misfolded protein resulting in its defective trafficking to the cell surface and an impaired chloride secretion. Pharmacological treatments partially rescue F508del CFTR activity either directly by interacting with the mutant protein and/or indirectly by altering the cellular protein homeostasis. Here, we show that the phosphorylation of ezrin together with its binding to phosphatidylinositol-4,5-bisphosphate (PIP2) tethers the F508del CFTR to the actin cytoskeleton, stabilizing it on the apical membrane and rescuing the sub-membrane compartmentalization of cAMP and activated PKA. Both the small molecules trimethylangelicin (TMA) and VX-809, which act as 'correctors' for F508del CFTR by rescuing F508del-CFTR-dependent chloride secretion, also restore the apical expression of phosphorylated ezrin and actin organization and increase cAMP and activated PKA submembrane compartmentalization in both primary and secondary cystic fibrosis airway cells. Latrunculin B treatment or expression of the inactive ezrin mutant T567A reverse the TMA and VX-809-induced effects highlighting the role of corrector-dependent ezrin activation and actin re-organization in creating the conditions to generate a sub-cortical cAMP pool of adequate amplitude to activate the F508del-CFTR-dependent chloride secretion.
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Affiliation(s)
- Anna C Abbattiscianni
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Maria T Mancini
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Rosa A Cardone
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Stefania Monterisi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Stefano Castellani
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Onofrio Laselva
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
| | - Francesca Di Sole
- Physiology and Pharmacology Department, Des Moines University, Des Moines, IA 50312, USA
| | - Massimo Conese
- Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Valeria Casavola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy
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Fouassier L, Fiorotto R. Ezrin finds its groove in cholangiocytes. Hepatology 2015; 61:1467-70. [PMID: 25545157 PMCID: PMC4406785 DOI: 10.1002/hep.27675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 12/18/2014] [Indexed: 12/07/2022]
Affiliation(s)
- Laura Fouassier
- INSERM, UMR_S 938, Centre de Recherche Saint-Antoine, F-75012, Paris, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 938, Centre de Recherche Saint-Antoine F-75012, Paris, France
| | - Romina Fiorotto
- Section of Digestive Diseases, Liver Center, Yale University School of Medicine, Cedar Street 333, New Haven, CT 06520, USA
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Zinn VZ, Khatri A, Mednieks MI, Hand AR. Localization of cystic fibrosis transmembrane conductance regulator signaling complexes in human salivary gland striated duct cells. Eur J Oral Sci 2015; 123:140-8. [PMID: 25903037 DOI: 10.1111/eos.12184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2015] [Indexed: 02/03/2023]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-dependent protein kinase (PKA)-regulated Cl(-) channel, crucial for epithelial cell regulation of salt and water transport. Previous studies showed that ezrin, an actin binding and A-kinase anchoring protein (AKAP), facilitates association of PKA with CFTR. We used immunohistochemistry and immunogold transmission electron microscopy to localize CFTR, ezrin, and PKA type II regulatory (RII) and catalytic (C) subunits in striated duct cells of human parotid and submandibular glands. Immunohistochemistry localized the four proteins mainly to the apical membrane and the apical cytoplasm of striated duct cells. In acinar cells, ezrin localized to the luminal membrane, and PKA RII subunits were present in secretory granules, as previously described. Immunogold labeling showed that CFTR and PKA RII and C subunits were localized to the luminal membrane and associated with apical granules and vesicles of striated duct cells. Ezrin was present along the luminal membrane, on microvilli and along the junctional complexes between cells. Double labeling showed specific protein associations with apical granules and vesicles and along the luminal membrane. Ezrin, CFTR, and PKA RII and C subunits are co-localized in striated duct cells, suggesting the presence of signaling complexes that serve to regulate CFTR activity.
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Affiliation(s)
- Vina Z Zinn
- University of Connecticut School of Dental Medicine, Farmington, CT, USA
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Deming PB, Campbell SL, Stone JB, Rivard RL, Mercier AL, Howe AK. Anchoring of protein kinase A by ERM (ezrin-radixin-moesin) proteins is required for proper netrin signaling through DCC (deleted in colorectal cancer). J Biol Chem 2015; 290:5783-96. [PMID: 25575591 DOI: 10.1074/jbc.m114.628644] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Netrin-1, acting through its principal receptor DCC (deleted in colorectal cancer), serves as an axon guidance cue during neural development and also contributes to vascular morphogenesis, epithelial migration, and the pathogenesis of some tumors. Several lines of evidence suggest that netrin-DCC signaling can regulate and be regulated by the cAMP-dependent protein kinase, PKA, although the molecular details of this relationship are poorly understood. Specificity in PKA signaling is often achieved through differential subcellular localization of the enzyme by interaction with protein kinase A anchoring proteins (AKAPs). Here, we show that AKAP function is required for DCC-mediated activation of PKA and phosphorylation of cytoskeletal regulatory proteins of the Mena/VASP (vasodilator-stimulated phosphoprotein) family. Moreover, we show that DCC and PKA physically interact and that this association is mediated by the ezrin-radixin-moesin (ERM) family of plasma membrane-actin cytoskeleton cross-linking proteins. Silencing of ERM protein expression inhibits DCC-PKA interaction, DCC-mediated PKA activation, and phosphorylation of Mena/VASP proteins as well as growth cone morphology and neurite outgrowth. Finally, although expression of wild-type radixin partially rescued growth cone morphology and tropism toward netrin in ERM-knockdown cells, expression of an AKAP-deficient mutant of radixin did not fully rescue growth cone morphology and switched netrin tropism from attraction to repulsion. These data support a model in which ERM-mediated anchoring of PKA activity to DCC is required for proper netrin/DCC-mediated signaling.
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Affiliation(s)
- Paula B Deming
- From the Department of Medical Laboratory and Radiation Sciences, the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and
| | - Shirley L Campbell
- the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and Department of Pharmacology, and the Department of Pharmacology, Université de Montréal, Montréal, Quebec H3C3J7 Canada
| | | | | | | | - Alan K Howe
- the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and Department of Pharmacology, and
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Ivonnet P, Salathe M, Conner GE. Hydrogen peroxide stimulation of CFTR reveals an Epac-mediated, soluble AC-dependent cAMP amplification pathway common to GPCR signalling. Br J Pharmacol 2014; 172:173-84. [PMID: 25220136 DOI: 10.1111/bph.12934] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 08/27/2014] [Accepted: 09/03/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE H2 O2 is widely understood to regulate intracellular signalling. In airway epithelia, H2 O2 stimulates anion secretion primarily by activating an autocrine PGE2 signalling pathway via EP4 and EP1 receptors to initiate cytic fibrosis transmembrane regulator (CFTR)-mediated Cl(-) secretion. This study investigated signalling downstream of the receptors activated by H2 O2 . EXPERIMENTAL APPROACH Anion secretion by differentiated bronchial epithelial cells was measured in Ussing chambers during stimulation with H2 O2 , an EP4 receptor agonist or β2 -adrenoceptor agonist in the presence and absence of inhibitors of ACs and downstream effectors. Intracellular calcium ([Ca(2+) ]I ) changes were followed by microscopy using fura-2-loaded cells and PKA activation followed by FRET microscopy. KEY RESULTS Transmembrane adenylyl cyclase (tmAC) and soluble AC (sAC) were both necessary for H2 O2 and EP4 receptor-mediated CFTR activation in bronchial epithelia. H2 O2 and EP4 receptor agonist stimulated tmAC to increase exchange protein activated by cAMP (Epac) activity that drives PLC activation to raise [Ca(2+) ]i via Ca(2+) store release (and not entry). Increased [Ca(2+) ]i led to sAC activation and further increases in CFTR activity. Stimulation of sAC did not depend on changes in [HCO3 (-) ]. Ca(2+) -activated apical KCa 1.1 channels and cAMP-activated basolateral KV 7.1 channels contributed to H2 O2 -stimulated anion currents. A similar Epac-mediated pathway was seen following β2 -adrenoceptor or forskolin stimulation. CONCLUSIONS AND IMPLICATIONS H2 O2 initiated a complex signalling cascade that used direct stimulation of tmACs by Gαs followed by Epac-mediated Ca(2+) crosstalk to activate sAC. The Epac-mediated Ca(2+) signal constituted a positive feedback loop that amplified CFTR anion secretion following stimulation of tmAC by a variety of stimuli.
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Affiliation(s)
- P Ivonnet
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Miami, Miami, Florida, USA
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Vachel L, Norez C, Jayle C, Becq F, Vandebrouck C. The low PLC-δ1 expression in cystic fibrosis bronchial epithelial cells induces upregulation of TRPV6 channel activity. Cell Calcium 2014; 57:38-48. [PMID: 25477137 DOI: 10.1016/j.ceca.2014.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/20/2014] [Accepted: 11/11/2014] [Indexed: 11/28/2022]
Abstract
Increase of Ca(2+) influx in Cystic Fibrosis (CF) cells has been reported to be related to Transient Receptor Potential Canonical (TRPC6) channel, which is implicated in a functional coupling with Cystic Fibrosis Transmembrane conductance Regulator (CFTR). Several members of the Transient Receptor Potential Vanilloid (TRPV) channels family have already been described as emerging target for respiratory diseases. Two specific isoforms, TRPV5 and TRPV6 are of particular interest in the context of CF Ca(2+) homeostasis as they are highly selective toward Ca(2+) and constitutively activated. Thus, we investigated the involvement of these channels in Ca(2+) influx in CF and non-CF human bronchial epithelial cell lines. 16HBE14o-, CFBE41o- cell lines, primary human airway epithelial cells (hAEC) and freshly isolated human airway epithelial cells from CF and non-CF individuals were used. We showed that both channels are expressed in CF and non-CF cells and constitutive Ca(2+) influx was significantly higher (85%) in cells from CF individuals compared to cells from non-CF ones. Using the selective inhibitor of TRPV6 channel SOR-C27 and a siRNA strategy, our results revealed that TRPV6 was mostly involved in the increase of Ca(2+) influx. TRPV6 channel is negatively regulated by the PLC-PIP2 pathway. We measured the Ca(2+) influx in the presence of the non-specific PLC inhibitor, U73122, in non-CF human bronchial epithelial cells. Ca(2+) influx was increased by 33% with U73122 and this increase was largely reduced in the presence of SOR-C27. PLC inhibition in CF cells by U73122 had no effect on Ca(2+) influx. These results showed that PLC-PIP2 pathway is dysregulated in CF cells and leads to the increase of TRPV6 activity. The regulation of TRPV6 by PLC-PIP2 pathway implicates the specific PLC isoform, PLC-δ1. Immunoblot experiments revealed that expression of PLC-δ1 was decreased by 70% in CF cells. TRPV6 activity was normalized but not the level of expression of PLC-δ1 protein after F508del-CFTR rescue by low temperature for 48 h or treated for 24 h by 10 μM VX-809 in CF cells. This study revealed TRPV6 and PLC-δ1 as critical actor of Ca(2+) homeostasis in CF human bronchial epithelial cells.
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Affiliation(s)
- Laura Vachel
- Laboratoire Signalisation et Transports Ioniques Membranaires ERL 7368 CNRS, Université de Poitiers, 86073 Poitiers, France
| | - Caroline Norez
- Laboratoire Signalisation et Transports Ioniques Membranaires ERL 7368 CNRS, Université de Poitiers, 86073 Poitiers, France
| | - Christophe Jayle
- Service de Chirurgie Cardiothoracique, CHU Poitiers, Poitiers, France
| | - Frédéric Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires ERL 7368 CNRS, Université de Poitiers, 86073 Poitiers, France
| | - Clarisse Vandebrouck
- Laboratoire Signalisation et Transports Ioniques Membranaires ERL 7368 CNRS, Université de Poitiers, 86073 Poitiers, France.
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Monterisi S, Casavola V, Zaccolo M. Local modulation of cystic fibrosis conductance regulator: cytoskeleton and compartmentalized cAMP signalling. Br J Pharmacol 2014; 169:1-9. [PMID: 23072488 DOI: 10.1111/bph.12017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/12/2012] [Accepted: 10/05/2012] [Indexed: 11/28/2022] Open
Abstract
The cystic fibrosis conductance regulator (CFTR) is a cAMP-regulated Cl(-) channel expressed predominantly at the apical membrane of secreting epithelial cells. Mutations in the CFTR gene lead to cystic fibrosis, the most frequent genetic disease in the Caucasian population. The most common mutation, a deletion of phenylalanine at position 508 (F508del), impairs CFTR folding and chloride channel function. Although an intense effort is under way to identify compounds that target the F508del CFTR structural defect and promote its expression and stability at the plasma membrane, so far their clinical efficacy has proven to be poor, highlighting the necessity to better understand the molecular mechanism of CFTR regulation and of the pathogenesis of the disease. Accumulating evidence suggests that the inclusion of the CFTR in macromolecular complexes and its interaction with the cortical cytoskeleton may play a key role in fine-tuning the regulation of channel function. Here we review some recent findings that support a critical role for protein-protein interactions involving CFTR and for the cytoskeleton in promoting local control of channel activity. These findings indicate that compounds that rescue and stabilize CFTR at the apical membrane may not be sufficient to restore its function unless the appropriate intracellular milieu is also reconstituted.
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Affiliation(s)
- Stefania Monterisi
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford, UK
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Stimulation of β2-adrenergic receptor increases CFTR function and decreases ATP levels in murine hematopoietic stem/progenitor cells. J Cyst Fibros 2014; 14:26-33. [PMID: 25178873 DOI: 10.1016/j.jcf.2014.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/15/2014] [Accepted: 08/11/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND The chloride channel CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) is expressed by many cell types, including hematopoietic stem/progenitor cells (HSPCs). In this study, we sought to better comprehend the regulation of CFTR activity in HSPCs, namely by beta-adrenergic stimuli. METHODS The expression of β2-adrenergic receptor (β2-AR) in murine Sca-1(+) HSPCs was investigated by immunofluorescence/confocal microscopy and flow-cytometric analysis. Association with CFTR was assessed by immunoprecipitation. HSPCs were evaluated for ATP content and CFTR activity by means of luminometric and spectrofluorometric methods, respectively, upon stimulation with salbutamol. RESULTS HSPCs express β2-AR over the whole plasma membrane and are associated in cellula with both the immature and mature forms of CFTR. β2-AR was predominantly expressed by HSPCs with bigger size. CFTR channel activity was increased by salbutamol treatment and this activation was inhibited by either a specific CFTR inhibitor (CFTRinh172) or a β2-AR receptor inhibitor (ICI 118,551). Intracellular ATP levels were reduced by salbutamol stimulation and this effect was reversed when ICI 118,551 or CFTR inhibitors were present. A trend in the increase of extracellular ATP upon salbutamol stimulation was observed. CONCLUSIONS In HSPCs, CFTR is regulated by β2-adrenergic receptor stimulation determining intracellular ATP depletion.
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Abstract
Macromolecular structures embedded in the cell plasma membrane called ‘porosomes’, are involved in the regulated fractional release of intravesicular contents from cells during secretion. Porosomes range in size from 15 nm in neurons and astrocytes to 100-180 nm in the exocrine pancreas and neuroendocrine cells. Porosomes have been isolated from a number of cells, and their morphology, composition, and functional reconstitution well documented. The 3D contour map of the assembly of proteins within the porosome complex, and its native X-ray solution structure at sub-nm resolution has also advanced. This understanding now provides a platform to address diseases that may result from secretory defects. Water and ion binding to mucin impart hydration, critical for regulating viscosity of the mucus in the airways epithelia. Appropriate viscosity is required for the movement of mucus by the underlying cilia. Hence secretion of more viscous mucus prevents its proper transport, resulting in chronic and fatal airways disease such as cystic fibrosis (CF). CF is caused by the malfunction of CF transmembrane conductance regulator (CFTR), a chloride channel transporter, resulting in viscous mucus in the airways. Studies in mice lacking functional CFTR secrete highly viscous mucous that adhered to the epithelium. Since CFTR is known to interact with the t-SNARE protein syntaxin-1A, and with the chloride channel CLC-3, which are also components of the porosome complex, the interactions between CFTR and the porosome complex in the mucin-secreting human airway epithelial cell line Calu-3 was hypothesized and tested. Results from the study demonstrate the presence of approximately 100 nm in size porosome complex composed of 34 proteins at the cell plasma membrane in Calu-3 cells, and the association of CFTR with the complex. In comparison, the nuclear pore complex measures 120 nm and is comprised of over 500 protein molecules. The involvement of CFTR in porosome-mediated mucin secretion is hypothesized, and is currently being tested.
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Affiliation(s)
- Bhanu P Jena
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
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Hou X, Lewis KT, Wu Q, Wang S, Chen X, Flack A, Mao G, Taatjes DJ, Sun F, Jena BP. Proteome of the porosome complex in human airway epithelia: interaction with the cystic fibrosis transmembrane conductance regulator (CFTR). J Proteomics 2013; 96:82-91. [PMID: 24220302 DOI: 10.1016/j.jprot.2013.10.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/20/2013] [Accepted: 10/31/2013] [Indexed: 01/11/2023]
Abstract
UNLABELLED The surface of the airways is coated with a thin film of mucus composed primarily of mucin, which is under continuous motion via ciliary action. Mucin not only serves to lubricate the airways epithelia, but also functions as a trap for foreign particles and pathogens, thereby assisting in keeping the airways clean and free of particulate matter and infections. Altered mucin secretion especially increased mucin viscosity, results in mucin stagnation due to the inability of the cilia to propel them, leading to infections and diseases such as cystic fibrosis (CF). Since porosomes have been demonstrated to be the secretory portals at the cell plasma membrane in cells, their presence, structure, and composition in the mucin-secreting human airway epithelial cell line Calu-3 expressing CF transmembrane receptor (CFTR), were investigated. Atomic force microscopy (AFM) of Calu-3 cells demonstrates the presence of approximately 100nm in diameter porosome openings at the plasma membrane surface. Electron microscopy confirms the AFM results, and tandem mass spectrometry and immunoanalysis performed on isolated Calu-3 porosomes, reveal the association of CFTR with the porosome complex. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease. BIOLOGICAL SIGNIFICANCE In the present study, the porosome proteome in human airway epithelia has been determined. The interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) and the porosome complex in the human airway epithelia is further demonstrated. The possible regulation by CFTR on the quality of mucus secretion via the porosome complex at the cell plasma membrane is hypothesized. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease.
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Affiliation(s)
- Xia Hou
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Kenneth T Lewis
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Qingtian Wu
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Sunxi Wang
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Amanda Flack
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Guangzhao Mao
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Douglas J Taatjes
- Department of Pathology, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Fei Sun
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Bhanu P Jena
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA.
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Frizzell RA, Hanrahan JW. Physiology of epithelial chloride and fluid secretion. Cold Spring Harb Perspect Med 2013; 2:a009563. [PMID: 22675668 DOI: 10.1101/cshperspect.a009563] [Citation(s) in RCA: 154] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epithelial salt and water secretion serves a variety of functions in different organ systems, such as the airways, intestines, pancreas, and salivary glands. In cystic fibrosis (CF), the volume and/or composition of secreted luminal fluids are compromised owing to mutations in the gene encoding CFTR, the apical membrane anion channel that is responsible for salt secretion in response to cAMP/PKA stimulation. This article examines CFTR and related cellular transport processes that underlie epithelial anion and fluid secretion, their regulation, and how these processes are altered in CF disease to account for organ-specific secretory phenotypes.
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Affiliation(s)
- Raymond A Frizzell
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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Baumann O, Bauer A. Development of apical membrane organization and V-ATPase regulation in blowfly salivary glands. J Exp Biol 2013; 216:1225-34. [DOI: 10.1242/jeb.077420] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
SUMMARY
Secretory cells in blowfly salivary gland are specialized via morphological and physiological attributes in order to serve their main function, i.e. the transport of solutes at a high rate in response to a hormonal stimulus, namely serotonin (5-HT). This study examines the way that 5-HT-insensitive precursor cells differentiate into morphologically complex 5-HT-responsive secretory cells. By means of immunofluorescence microscopy, immunoblotting and measurements of the transepithelial potential changes, we show the following. (1) The apical membrane of the secretory cells becomes organized into an elaborate system of canaliculi and is folded into pleats during the last pupal day and the first day of adulthood. (2) The structural reorganization of the apical membrane is accompanied by an enrichment of actin filaments and phosphorylated ERM protein (phospho-moesin) at this membrane domain and by the deployment of the membrane-integral part of vacuolar-type H+-ATPase (V-ATPase). These findings suggest a role for phospho-moesin, a linker between actin filaments and membrane components, in apical membrane morphogenesis. (3) The assembly and activation of V-ATPase can be induced immediately after eclosion by way of 8-CPT-cAMP, a membrane-permeant cAMP analogue. (4) 5-HT, however, produces the assembly and activation of V-ATPase only in flies aged for at least 2 h after eclosion, indicating that, at eclosion, the 5-HT receptor/adenylyl cyclase/cAMP signalling pathway is inoperative upstream of cAMP. (5) 5-HT activates both the Ca2+ signalling pathway and the cAMP signalling cascade in fully differentiated secretory cells. However, the functionality of these signalling cascades does not seem to be established in a tightly coordinated manner during cell differentation.
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Affiliation(s)
- Otto Baumann
- Institut für Biochemie und Biologie, Zoophysiologie, Universität Potsdam, Karl-Liebknecht-Str. 24–25, 14476 Potsdam, Germany
| | - Alexandra Bauer
- Institut für Biochemie und Biologie, Zoophysiologie, Universität Potsdam, Karl-Liebknecht-Str. 24–25, 14476 Potsdam, Germany
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van Meegen MA, Terheggen-Lagro SWJ, Koymans KJ, van der Ent CK, Beekman JM. Apical CFTR expression in human nasal epithelium correlates with lung disease in cystic fibrosis. PLoS One 2013; 8:e57617. [PMID: 23483918 PMCID: PMC3590182 DOI: 10.1371/journal.pone.0057617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 01/24/2013] [Indexed: 02/06/2023] Open
Abstract
Introduction Although most individuals with cystic fibrosis (CF) develop progressive obstructive lung disease, disease severity is highly variable, even for individuals with similar CFTR mutations. Measurements of chloride transport as expression of CFTR function in nasal epithelial cells correlate with pulmonary function and suggest that F508del-CFTR is expressed at the apical membrane. However, an association between quantitative apical CFTR expression in nasal epithelium and CF disease severity is still missing. Methods and Materials Nasal epithelial cells from healthy individuals and individuals with CF between 12–18 years were obtained by nasal brushing. Apical CFTR expression was measured by confocal microscopy using CFTR mAb 596. Expression was compared between both groups and expression in CF nasal epithelial cells was associated with standardized pulmonary function (FEV1%). Results The proportion of cells expressing apical CFTR in columnar epithelium is lower in CF compared to non-CF. The apical CFTR expression level was significantly correlated with FEV1% in F508del homozygous subjects (r = 0.63, p = 0.012). Conclusion CFTR expression in nasal epithelial cells is lower in subjects with CF compared to healthy subjects. The proportion of cells expressing F508del-CFTR at the apical membrane is variable between subjects and is positively correlated with FEV1% in F508del-CFTR homozygous subjects.
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Affiliation(s)
- Marit Arianne van Meegen
- Department of Pediatric Pulmonology, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Molecular and Cellular Intervention, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Kirsten Judith Koymans
- Department of Pediatric Pulmonology, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Molecular and Cellular Intervention, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Jeffrey Matthijn Beekman
- Department of Pediatric Pulmonology, University Medical Center Utrecht, Utrecht, The Netherlands
- Centre for Molecular and Cellular Intervention, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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Ezrin is required for the functional regulation of the epithelial sodium proton exchanger, NHE3. PLoS One 2013; 8:e55623. [PMID: 23405179 PMCID: PMC3566197 DOI: 10.1371/journal.pone.0055623] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 12/31/2012] [Indexed: 11/19/2022] Open
Abstract
The sodium hydrogen exchanger isoform 3 (NHE3) mediates absorption of sodium, bicarbonate and water from renal and intestinal lumina. This activity is fundamental to the maintenance of a physiological plasma pH and blood pressure. To perform this function NHE3 must be present in the apical membrane of renal tubular and intestinal epithelia. The molecular determinants of this localization have not been conclusively determined, although linkage to the apical actin cytoskeleton through ezrin has been proposed. We set out to evaluate this hypothesis. Functional studies of NHE3 activity were performed on ezrin knockdown mice (Vil2kd/kd) and NHE3 activity similar to wild-type animals detected. Interpretation of this finding was difficult as other ERM (ezrin/radixin/moesin) proteins were present. We therefore generated an epithelial cell culture model where ezrin was the only detectable ERM. After knockdown of ezrin expression with siRNA, radixin and moesin expression remained undetectable. Consistent with the animal ultrastructural data, cells lacking ezrin retained an epithelial phenotype but had shortened and thicker microvilli. NHE3 localization was identical to cells transfected with non-targeting siRNA. The attachment of NHE3 to the apical cytoskeleton was unaltered as assessed by fluorescent recovery after photobleaching (FRAP) and the solubility of NHE3 in Triton X-100. Baseline NHE3 activity was unaltered, however, cAMP-dependent inhibition of NHE3 was largely lost even though NHE3 was phosphorylated at serines 552 and 605. Thus, ezrin is not necessary for the apical localization, attachment to the cytoskeleton, baseline activity or cAMP induced phosphrylation of NHE3, but instead is required for cAMP mediated inhibition.
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Carmosino M, Rizzo F, Procino G, Zolla L, Timperio AM, Basco D, Barbieri C, Torretta S, Svelto M. Identification of moesin as NKCC2-interacting protein and analysis of its functional role in the NKCC2 apical trafficking. Biol Cell 2012; 104:658-76. [PMID: 22708623 DOI: 10.1111/boc.201100074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 06/15/2012] [Indexed: 12/16/2022]
Abstract
BACKGROUND INFORMATION The renal Na(+) -K(+) -2Cl(-) co-transporter (NKCC2) is expressed in kidney thick ascending limb cells, where it mediates NaCl re-absorption regulating body salt levels and blood pressure. RESULTS In this study, we used a well-characterised NKCC2 construct (c-NKCC2) to identify NKCC2-interacting proteins by an antibody shift assay coupled with blue native/SDS-PAGE and mass spectrometry. Among the interacting proteins, we identified moesin, a protein belonging to ezrin, eadixin and moesin family. Co-immunoprecipitation experiments confirmed that c-NKCC2 interacts with the N-terminal domain of moesin in LLC-PK1 cells. Moreover, c-NKCC2 accumulates in intracellular and sub-apical vesicles in cells transfected with a moesin dominant negative green fluorescent protien (GFP)-tagged construct. In addition, moesin knock-down by short interfering RNA decreases by about 50% c-NKCC2 surface expression. Specifically, endocytosis and exocytosis assays showed that moesin knock-down does not affect c-NKCC2 internalisation but strongly reduces exocytosis of the co-transporter. CONCLUSIONS Our data clearly demonstrate that moesin plays a critical role in apical membrane insertion of NKCC2, suggesting a possible involvement of moesin in regulation of Na(+) and Cl(-) absorption in the kidney.
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Affiliation(s)
- Monica Carmosino
- Department of Biosciences, Biotechnologies and Pharmacological Sciences, University of Bari, 70126 Bari, Italy.
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Chen J, Fok KL, Chen H, Zhang XH, Xu WM, Chan HC. Cryptorchidism-induced CFTR down-regulation results in disruption of testicular tight junctions through up-regulation of NF-κB/COX-2/PGE2. Hum Reprod 2012; 27:2585-97. [PMID: 22777528 DOI: 10.1093/humrep/des254] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
STUDY QUESTION Does elevated temperature-induced cystic fibrosis transmembrane conductance regulator (CFTR) down-regulation in Sertoli cells in cryptorchid testis disrupt testicular tight junctions (TJs) through the nuclear factor kappa B (NF-κB)/cyclooxygenase-2 (COX-2)/prostaglandin E(2) (PGE(2)) pathway? SUMMARY ANSWER Our results suggest that CFTR may be involved in regulating testicular TJs and the blood-testis barrier (BTB) through its negative regulation of the NF-κB/COX-2/PGE(2) pathway in Sertoli cells, a defect of which may result in the spermatogenesis defect in cryptorchidism. WHAT IS KNOWN ALREADY Cryptorchidism, or undescended testes, is known to result in defective spermatogenesis. Although an elevated testicular temperature is regarded as an important factor affecting spermatogenesis in cryptorchidism, the exact mechanism remains elusive. It is known that the expression of functional CFTR is temperature sensitive. Our previous study has demonstrated that CFTR negatively regulates NF-κB/COX-2/PGE(2) in bronchial epithelial cells. Disruption of TJs by COX-2/PGE(2) has been found in tumour cells. STUDY DESIGN AND METHODS Expression of CFTR, NF-κB, COX-2 and TJ proteins was examined in the testes of a surgical-induced cryptorchidism mouse model and a testicular hyperthermia mouse model, as well as in control or CFTR-inhibited/knocked down primary rat Sertoli cells. PGE(2) production was measured by ELISA. Sertoli cell barrier function was determined by transepethelial resistance (TER) measurements in rat Sertoli cell primary cultures. BTB integrity in the cryptorchidism model was monitored by examining tracker dye injected into seminiferous tubules. MAIN RESULTS Down-regulation of CFTR accompanied by activation of NF-κB, up-regulation of COX-2 and down-regulation of TJ proteins, including ZO-1 and occludin, was observed in a cryptorchidism mouse model. BTB leakage revealed impaired BTB integrity in cryptorchid testes, confirming the destruction of TJs. The inverse correlation of CFTR and COX-2 was further confirmed in a mouse testis hyperthermia model and CFTR knockout mouse model. Culturing primary Sertoli cells at 37°C, which mimics the pathological condition of cryptorchidism, led to a significant decrease in CFTR and increase in COX-2 expression and PGE(2) production compared with the culture at the physiological 32°C. Inhibition or knockdown of CFTR led to increased COX-2 but decreased ZO-1 and occludin expression in Sertoli cells, which could be mimicked by PGE(2), but reversed by NF-κB or COX-2 inhibitor, suggesting that the regulation of TJs by CFTR is mediated by a NF-κB/COX-2/PGE(2) pathway. Inhibition of CFTR or administration of PGE(2) significantly decreased Sertoli cell TER. LIMITATIONS This study has tested only the CFTR/NF-κB/COX-2/PGE(2) pathway in mouse testes in vivo and in rat Sertoli cells in vitro, and thus, it has some limitations. Further investigations in other species, especially humans, are needed. WIDER IMPLICATIONS OF THE FINDINGS Our study may shed more light on one of the aspects of the complicated underlying mechanisms of defective spermatogenesis induced by cryptorchidism.
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Affiliation(s)
- Jing Chen
- Epithelial Cell Biology Research Center, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, NT, Hong Kong
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Monterisi S, Favia M, Guerra L, Cardone RA, Marzulli D, Reshkin SJ, Casavola V, Zaccolo M. CFTR regulation in human airway epithelial cells requires integrity of the actin cytoskeleton and compartmentalized cAMP and PKA activity. J Cell Sci 2012; 125:1106-17. [PMID: 22302988 DOI: 10.1242/jcs.089086] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) mutation ΔF508CFTR still causes regulatory defects when rescued to the apical membrane, suggesting that the intracellular milieu might affect its ability to respond to cAMP regulation. We recently reported that overexpression of the Na(+)/H(+) exchanger regulatory factor NHERF1 in the cystic fibrosis (CF) airway cell line CFBE41o-rescues the functional expression of ΔF508CFTR by promoting F-actin organization and formation of the NHERF1-ezrin-actin complex. Here, using real-time FRET reporters of both PKA activity and cAMP levels, we find that lack of an organized subcortical cytoskeleton in CFBE41o-cells causes both defective accumulation of cAMP in the subcortical compartment and excessive cytosolic accumulation of cAMP. This results in reduced subcortical levels and increased cytosolic levels of PKA activity. NHERF1 overexpression in CFBE41o-cells restores chloride secretion, subcortical cAMP compartmentalization and local PKA activity, indicating that regulation of ΔF508CFTR function requires not only stable expression of the mutant CFTR at the cell surface but also depends on both generation of local cAMP signals of adequate amplitude and activation of PKA in proximity of its target. Moreover, we found that the knockdown of wild-type CFTR in the non-CF 16HBE14o-cells results in both altered cytoskeletal organization and loss of cAMP compartmentalization, whereas stable overexpression of wt CFTR in CF cells restores cytoskeleton organization and re-establishes the compartmentalization of cAMP at the plasma membrane. This suggests that the presence of CFTR on the plasma membrane influences the cytoskeletal organizational state and, consequently, cAMP distribution. Our data show that a sufficiently high concentration of cAMP in the subcortical compartment is required to achieve PKA-mediated regulation of CFTR activity.
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Affiliation(s)
- Stefania Monterisi
- Department of General and Environmental Physiology, University of Bari, Bari, 70125, Italy
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Averna M, Stifanese R, De Tullio R, Minicucci L, Cresta F, Palena S, Salamino F, Pontremoli S, Melloni E. Evidence for alteration of calpain/calpastatin system in PBMC of cystic fibrosis patients. Biochim Biophys Acta Mol Basis Dis 2011; 1812:1649-57. [PMID: 21983488 DOI: 10.1016/j.bbadis.2011.09.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 09/21/2011] [Accepted: 09/23/2011] [Indexed: 02/04/2023]
Abstract
We are here reporting that in peripheral blood mononuclear cells (PBMC) of patients homozygous for F508del-CFTR the calpain-calpastatin system undergoes a profound alteration. In fact, calpain basal activity, almost undetectable in control PBMC, becomes measurable at a significant extent in cells from cystic fibrosis (CF) patients, also due to a 40-60% decrease in both calpastatin protein and inhibitory activity. Constitutive protease activation in CF patients' cells induces a large accumulation of the mutated cystic fibrosis transmembrane conductance regulator (CFTR) in the 100kD+70kD split forms as well as a degradation of proteins associated to the CFTR complex. Specifically, the scaffolding protein Na(+)/H(+) exchanger 3 regulatory factor-1 (NHERF-1) is converted in two distinct fragments showing masses of 35kD and 20kD, being however the latter form the most represented one, thereby indicating that in CF-PBMC the CFTR complex undergoes a large disorganization. In conclusion, our observations are providing new information on the role of calpain in the regulation of plasma membrane ion conductance and provide additional evidence on the transition of this protease activity from a physiological to a pathological function.
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Affiliation(s)
- Monica Averna
- Department of Experimental Medicine, University of Genoa, Viale Benedetto XV, Genoa, Italy
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Stolarczyk EI, Reiling CJ, Paumi CM. Regulation of ABC transporter function via phosphorylation by protein kinases. Curr Pharm Biotechnol 2011; 12:621-35. [PMID: 21118091 DOI: 10.2174/138920111795164075] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 04/07/2010] [Indexed: 11/22/2022]
Abstract
ATP-binding cassette (ABC) transporters are multispanning membrane proteins that utilize ATP to move a broad range of substrates across cellular membranes. ABC transporters are involved in a number of human disorders and diseases. Overexpression of a subset of the transporters has been closely linked to multidrug resistance in both bacteria and viruses and in cancer. A poorly understood and important aspect of ABC transporter biology is the role of phosphorylation as a mechanism to regulate transporter function. In this review, we summarize the current literature addressing the role of phosphorylation in regulating ABC transporter function. A comprehensive list of all the phosphorylation sites that have been identified for the human ABC transporters is presented, and we discuss the role of individual kinases in regulating transporter function. We address the potential pitfalls and difficulties associated with identifying phosphorylation sites and the corresponding kinase(s), and we discuss novel techniques that may circumvent these problems. We conclude by providing a brief perspective on studying ABC transporter phosphorylation.
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Schneider A, LaRusch J, Sun X, Aloe A, Lamb J, Hawes R, Cotton P, Brand RE, Anderson MA, Money ME, Banks PA, Lewis MD, Baillie J, Sherman S, DiSario J, Burton FR, Gardner TB, Amann ST, Gelrud A, George R, Kassabian S, Martinson J, Slivka A, Yadav D, Oruc N, Barmada MM, Frizzell R, Whitcomb DC, Whitcomb DC. Combined bicarbonate conductance-impairing variants in CFTR and SPINK1 variants are associated with chronic pancreatitis in patients without cystic fibrosis. Gastroenterology 2011; 140:162-71. [PMID: 20977904 PMCID: PMC3171690 DOI: 10.1053/j.gastro.2010.10.045] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/14/2010] [Accepted: 10/15/2010] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Idiopathic chronic pancreatitis (ICP) is a complex inflammatory disorder associated with multiple genetic and environmental factors. In individuals without cystic fibrosis (CF), variants of CFTR that inhibit bicarbonate conductance but maintain chloride conductance might selectively impair secretion of pancreatic juice, leading to trypsin activation and pancreatitis. We investigated whether sequence variants in the gene encoding the pancreatic secretory trypsin inhibitor SPINK1 further increase the risk of pancreatitis in these patients. METHODS We screened patients and controls for variants in SPINK1 associated with risk of chronic pancreatitis and in all 27 exons of CFTR. The final study group included 53 patients with sporadic ICP, 27 probands with familial ICP, 150 unrelated controls, 375 additional controls for limited genotyping. CFTR wild-type and p.R75Q were cloned and expressed in HEK293 cells, and relative conductances of HCO(3)(-) and Cl(-) were measured. RESULTS SPINK1 variants were identified in 36% of subjects and 3% of controls (odds ratio [OR], 18.1). One variant of CFTR not associated with CF, p.R75Q, was found in 16% of subjects and 5.3% of controls (OR, 3.4). Coinheritance of CFTR p.R75Q and SPINK1 variants occurred in 8.75% of patients and 0.38% of controls (OR, 25.1). Patch-clamp recordings of cells that expressed CFTR p.R75Q showed normal chloride currents but significantly reduced bicarbonate currents (P = .0001). CONCLUSIONS The CFTR variant p.R75Q causes a selective defect in bicarbonate conductance and increases risk of pancreatitis. Coinheritance of p.R75Q or CF causing CFTR variants with SPINK1 variants significantly increases the risk of ICP.
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Affiliation(s)
| | - Jessica LaRusch
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | - Xiumei Sun
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh PA
| | - Amy Aloe
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | - Janette Lamb
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | - Robert Hawes
- Digestive Disease Center, Medical University of South Carolina, Charleston, SC
| | - Peter Cotton
- Digestive Disease Center, Medical University of South Carolina, Charleston, SC
| | - Randall E. Brand
- Department of Medicine, Evanston Northwestern Healthcare, Chicago IL
| | | | | | - Peter A. Banks
- Division of Gastroenterology, Brigham and Women’s Hospital, Boston MD
| | - Michele D. Lewis
- Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL
| | - John Baillie
- Department of Medicine, Duke University Medical Center, Durham NC
| | - Stuart Sherman
- Department of Medicine, Indiana University Medical Center, Indianapolis, IN
| | - James DiSario
- Monterey Bay Gastroenterology Consultants, Monterey, CA
| | - Frank R. Burton
- Department of Internal Medicine, St. Louis University School of Medicine, St Louis, MO
| | | | | | - Andres Gelrud
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH
| | - Ryan George
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | | | - Jeremy Martinson
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Pittsburgh PA
| | - Adam Slivka
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | - Dhiraj Yadav
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | - Nevin Oruc
- Department of Medicine, University of Pittsburgh, Pittsburgh PA
| | | | - Raymond Frizzell
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh PA
| | - David C. Whitcomb
- Department of Medicine, University of Pittsburgh, Pittsburgh PA, Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh PA, Department of Human Genetics, University of Pittsburgh, Pittsburgh PA
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Cyclic AMP-mediated immune regulation--overview of mechanisms of action in T cells. Cell Signal 2010; 23:1009-16. [PMID: 21130867 DOI: 10.1016/j.cellsig.2010.11.018] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 11/23/2010] [Accepted: 11/25/2010] [Indexed: 01/21/2023]
Abstract
The canonical second messenger cAMP is well established as a potent negative regulator of T cell immune function. Through protein kinase A (PKA) it regulates T cell function at the level of transcription factors, members of the mitogen-activated protein kinase pathway, phospholipases (PLs), Ras homolog (Rho)A and proteins involved in the control of cell cycle progression. Type I PKA is the predominant PKA isoform in T cells. Furthermore, whereas type II PKA is located at the centrosome, type I PKA is anchored close to the T cell receptor (TCR) in lipid rafts by the Ezrin-ERM-binding phosphoprotein of 50 kDa (EBP50)-phosphoprotein associated with glycosphingolipid-enriched microdomains (PAG) scaffold complex. The most TCR-proximal target for type I PKA is C-terminal Src kinase (Csk), which upon activation by raft recruitment and phosphorylation inhibits the Src family tyrosine kinases Lck and Fyn and thus functions to maintain T cell homeostasis. Recently, induction of cAMP levels in responder T cells has emerged as one of the mechanisms by which regulatory T (T(R)) cells execute their suppressive action. Thus, the cAMP-type I PKA-Csk pathway emerges as a putative target for therapeutic intervention in autoimmune disorders as well as in cancer, where T(R) cell-mediated suppression contributes to suboptimal local immune responses.
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