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D'Amico F, Lugarà C, Luppino G, Giuffrida C, Giorgianni Y, Patanè EM, Manti S, Gambadauro A, La Rocca M, Abbate T. The Influence of Neurotrophins on the Brain-Lung Axis: Conception, Pregnancy, and Neonatal Period. Curr Issues Mol Biol 2024; 46:2528-2543. [PMID: 38534776 DOI: 10.3390/cimb46030160] [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: 02/18/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 03/28/2024] Open
Abstract
Neurotrophins (NTs) are four small proteins produced by both neuronal and non-neuronal cells; they include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4). NTs can exert their action through both genomic and non-genomic mechanisms by interacting with specific receptors. Initial studies on NTs have identified them only as functional molecules of the nervous system. However, recent research have shown that some tissues and organs (such as the lungs, skin, and skeletal and smooth muscle) as well as some structural cells can secrete and respond to NTs. In addition, NTs perform several roles in normal and pathological conditions at different anatomical sites, in both fetal and postnatal life. During pregnancy, NTs are produced by the mother, placenta, and fetus. They play a pivotal role in the pre-implantation process and in placental and embryonic development; they are also involved in the development of the brain and respiratory system. In the postnatal period, it appears that NTs are associated with some diseases, such as sudden infant death syndrome (SIDS), asthma, congenital central hypoventilation syndrome (CCHS), and bronchopulmonary dysplasia (BPD).
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Affiliation(s)
- Federica D'Amico
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Cecilia Lugarà
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Giovanni Luppino
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Carlo Giuffrida
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Ylenia Giorgianni
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Eleonora Maria Patanè
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Sara Manti
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Antonella Gambadauro
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Mariarosaria La Rocca
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
| | - Tiziana Abbate
- Pediatric Unit, Department of Human Pathology in Adult and Developmental Age "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria 1, 98124 Messina, Italy
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Drake LY, Wicher SA, Roos BB, Khalfaoui L, Nesbitt L, Fang YH, Pabelick CM, Prakash YS. Functional role of glial-derived neurotrophic factor in a mixed allergen murine model of asthma. Am J Physiol Lung Cell Mol Physiol 2024; 326:L19-L28. [PMID: 37987758 PMCID: PMC11279745 DOI: 10.1152/ajplung.00099.2023] [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: 03/29/2023] [Revised: 11/01/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023] Open
Abstract
Our previous study showed that glial-derived neurotrophic factor (GDNF) expression is upregulated in asthmatic human lungs, and GDNF regulates calcium responses through its receptor GDNF family receptor α1 (GFRα1) and RET receptor in human airway smooth muscle (ASM) cells. In this study, we tested the hypothesis that airway GDNF contributes to airway hyperreactivity (AHR) and remodeling using a mixed allergen mouse model. Adult C57BL/6J mice were intranasally exposed to mixed allergens (ovalbumin, Aspergillus, Alternaria, house dust mite) over 4 wk with concurrent exposure to recombinant GDNF, or extracellular GDNF chelator GFRα1-Fc. Airway resistance and compliance to methacholine were assessed using FlexiVent. Lung expression of GDNF, GFRα1, RET, collagen, and fibronectin was examined by RT-PCR and histology staining. Allergen exposure increased GDNF expression in bronchial airways including ASM and epithelium. Laser capture microdissection of the ASM layer showed increased mRNA for GDNF, GFRα1, and RET in allergen-treated mice. Allergen exposure increased protein expression of GDNF and RET, but not GFRα1, in ASM. Intranasal administration of GDNF enhanced baseline responses to methacholine but did not consistently potentiate allergen effects. GDNF also induced airway thickening, and collagen deposition in bronchial airways. Chelation of GDNF by GFRα1-Fc attenuated allergen-induced AHR and particularly remodeling. These data suggest that locally produced GDNF, potentially derived from epithelium and/or ASM, contributes to AHR and remodeling relevant to asthma.NEW & NOTEWORTHY Local production of growth factors within the airway with autocrine/paracrine effects can promote features of asthma. Here, we show that glial-derived neurotrophic factor (GDNF) is a procontractile and proremodeling factor that contributes to allergen-induced airway hyperreactivity and tissue remodeling in a mouse model of asthma. Blocking GDNF signaling attenuates allergen-induced airway hyperreactivity and remodeling, suggesting a novel approach to alleviating structural and functional changes in the asthmatic airway.
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Affiliation(s)
- Li Y. Drake
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Sarah A. Wicher
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Benjamin B. Roos
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Latifa Khalfaoui
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Lisa Nesbitt
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Yun Hua Fang
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Christina M. Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Y. S. Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
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Ardizzone A, Bova V, Casili G, Filippone A, Lanza M, Repici A, Esposito E, Paterniti I. bFGF-like Activity Supported Tissue Regeneration, Modulated Neuroinflammation, and Rebalanced Ca 2+ Homeostasis following Spinal Cord Injury. Int J Mol Sci 2023; 24:14654. [PMID: 37834102 PMCID: PMC10572408 DOI: 10.3390/ijms241914654] [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: 08/17/2023] [Revised: 09/23/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
A spinal cord injury (SCI) is a well-defined debilitating traumatic event to the spinal cord that usually triggers permanent changes in motor, sensory, and autonomic functions. Injured tissue becomes susceptible to secondary mechanisms caused by SCIs, which include pro-inflammatory cytokine release, the activation of astrocytes and microglia, and increased neuronal sensibility. As a consequence, the production of factors such as GFAP, IBA-1, TNF-α, IL-1β, IFN-γ, and S100-β slow down or inhibit central nervous system (CNS) regeneration. In this regard, a thorough understanding of the mechanisms regulating the CNS, and specifically SCI, is essential for the development of new therapeutic strategies. It has been demonstrated that basic fibroblast growth factor (bFGF) was successful in the modulation of neurotrophic activity, also promoting neurite survival and tissue repair, thus resulting in the valuable care of CNS disorders. However, bFGF therapeutic use is limited due to the undesirable effects developed following its administration. Therefore, the synthetic compound mimetic of bFGF, SUN11602 (with chemical name 4-[[4-[[2-[(4-Amino-2,3,5,6-tetramethylphenyl)amino]acetyl]methylamino]-1-piperidinyl]methyl]benzamide), has been reported to show neuroprotective activities similar to those of bFGF, also demonstrating a good pharmacokinetic profile. Here, we aimed to investigate the neuroprotective activity of this bFGF-like compound in modulating tissue regeneration, neuroinflammation, and Ca2+ overload by using a subacute mouse model of SCI. SUN11602 (1, 2.5, and 5 mg/kg) was administered orally to mice for 72 h daily following the in vivo model of SCI, which was generated by the extradural compression of the spinal cord. The data obtained demonstrated that SUN11602 treatment considerably decreased motor alteration and diminished the neuroinflammatory state through the regulation of glial activation, the NF-κB pathway, and kinases. Additionally, by controlling Ca2+-binding proteins and restoring neurotrophin expression, we showed that SUN11602 therapy restored the equilibrium of the neuronal circuit. Because of these findings, bFGF-like compounds may be an effective tool for reducing inflammation in SCI patients while enhancing their quality of life.
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Affiliation(s)
| | | | | | | | | | | | - Emanuela Esposito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno D’Alcontres, 31, 98166 Messina, Italy; (A.A.); (V.B.); (G.C.); (A.F.); (M.L.); (A.R.); (I.P.)
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Manti S, Xerra F, Spoto G, Butera A, Gitto E, Di Rosa G, Nicotera AG. Neurotrophins: Expression of Brain-Lung Axis Development. Int J Mol Sci 2023; 24:ijms24087089. [PMID: 37108250 PMCID: PMC10138985 DOI: 10.3390/ijms24087089] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/08/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Neurotrophins (NTs) are a group of soluble growth factors with analogous structures and functions, identified initially as critical mediators of neuronal survival during development. Recently, the relevance of NTs has been confirmed by emerging clinical data showing that impaired NTs levels and functions are involved in the onset of neurological and pulmonary diseases. The alteration in NTs expression at the central and peripheral nervous system has been linked to neurodevelopmental disorders with an early onset and severe clinical manifestations, often named "synaptopathies" because of structural and functional synaptic plasticity abnormalities. NTs appear to be also involved in the physiology and pathophysiology of several airway diseases, neonatal lung diseases, allergic and inflammatory diseases, lung fibrosis, and even lung cancer. Moreover, they have also been detected in other peripheral tissues, including immune cells, epithelium, smooth muscle, fibroblasts, and vascular endothelium. This review aims to provide a comprehensive description of the NTs as important physiological and pathophysiological players in brain and lung development.
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Affiliation(s)
- Sara Manti
- Pediatric Unit, Department of Human and Pediatric Pathology "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria, 1, 98124 Messina, Italy
| | - Federica Xerra
- Pediatric Unit, Department of Human and Pediatric Pathology "Gaetano Barresi", AOUP G. Martino, University of Messina, Via Consolare Valeria, 1, 98124 Messina, Italy
| | - Giulia Spoto
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age, "Gaetano Barresi" University of Messina, 98124 Messina, Italy
| | - Ambra Butera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age, "Gaetano Barresi" University of Messina, 98124 Messina, Italy
| | - Eloisa Gitto
- Intensive Pediatric Unit, Department of Human Pathology of the Adult and Developmental Age, "Gaetano Barresi" University of Messina, 98124 Messina, Italy
| | - Gabriella Di Rosa
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age, "Gaetano Barresi" University of Messina, 98124 Messina, Italy
| | - Antonio Gennaro Nicotera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age, "Gaetano Barresi" University of Messina, 98124 Messina, Italy
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Khalfaoui L, Pabelick CM. Airway smooth muscle in contractility and remodeling of asthma: potential drug target mechanisms. Expert Opin Ther Targets 2023; 27:19-29. [PMID: 36744401 DOI: 10.1080/14728222.2023.2177533] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Asthma is characterized by enhanced airway contractility and remodeling where airway smooth muscle (ASM) plays a key role, modulated by inflammation. Understanding the mechanisms by which ASM contributes to these features of asthma is essential for the development of novel asthma therapies. AREAS COVERED Inflammation in asthma contributes to a multitude of changes within ASM including enhanced airway contractility, proliferation, and fibrosis. Altered intracellular calcium ([Ca2+]i) regulation or Ca2+ sensitization contributes to airway hyperreactivity. Increased airway wall thickness from ASM proliferation and fibrosis contributes to structural changes seen with asthma. EXPERT OPINION ASM plays a significant role in multiple features of asthma. Increased ASM contractility contributes to hyperresponsiveness, while altered ASM proliferation and extracellular matrix production promote airway remodeling both influenced by inflammation of asthma and conversely even influencing the local inflammatory milieu. While standard therapies such as corticosteroids or biologics target inflammation, cytokines, or their receptors to alleviate asthma symptoms, these approaches do not address the underlying contribution of ASM to hyperresponsiveness and particularly remodeling. Therefore, novel therapies for asthma need to target abnormal contractility mechanisms in ASM and/or the contribution of ASM to remodeling, particularly in asthmatics resistant to current therapies.
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Affiliation(s)
- Latifa Khalfaoui
- Departments of Anesthesiology & Perioperative Medicine Mayo Clinic, Rochester, MN, USA
| | - Christina M Pabelick
- Departments of Anesthesiology & Perioperative Medicine Mayo Clinic, Rochester, MN, USA.,Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
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Bhallamudi S, Roos BB, Teske JJ, Wicher SA, McConico A, M Pabelick C, Sathish V, Prakash YS. Glial-derived neurotrophic factor in human airway smooth muscle. J Cell Physiol 2021; 236:8184-8196. [PMID: 34170009 DOI: 10.1002/jcp.30489] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/18/2021] [Accepted: 06/09/2021] [Indexed: 11/09/2022]
Abstract
Airway smooth muscle (ASM) cells modulate the local airway milieu via production of inflammatory mediators and growth factors including classical neurotrophins, such as brain-derived neurotrophic factor (BDNF). The glial cell-derived neurotrophic factor (GDNF) family of ligands (GFLs) are nonclassical neurotrophins and their role in the airway is barely understood. The major GFLs, GDNF and Neurturin (NRTN) bind to GDNF family receptor (GFR) α1 and α2 respectively that pair with Ret receptor to accomplish signaling. In this study, we found GDNF is expressed in human lung and increased in adult asthma, while human ASM expresses GDNF and its receptors. Accordingly, we used human ASM cells to test the hypothesis that ASM expression and autocrine signaling by GFLs regulate [Ca2+ ]i . Serum-deprived ASM cells from non-asthmatics were exposed to 10 ng/ml GDNF or NRTN for 15 min (acute) or 24 h (chronic). In fura-2 loaded cells, acute GDNF or NRTN alone induced [Ca2+ ]i responses, and further enhanced responses to 1 µM ACh or 10 µM histamine. Ret inhibitor (SPP86; 10 µM) or specific GDNF chelator GFRα1-Fc (1 µg/ml) showed roles of these receptors in GDNF effects. In contrast, NRTN did not enhance [Ca2+ ]i response to histamine. Furthermore, conditioned media of nonasthmatic and asthmatic ASM cells showed GDNF secretion. SPP86, Ret inhibitor and GFRα1-Fc chelator markedly decreased [Ca2+ ]i response compared with vehicle, highlighting autocrine effects of secreted GDNF. Chronic GDNF treatment increased histamine-induced myosin light chain phosphorylation. These novel data demonstrate GFLs particularly GDNF/GFRα1 influence ASM [Ca2+ ]i and raise the possibility that GFLs are potential targets of airway hyperresponsiveness.
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Affiliation(s)
- Sangeeta Bhallamudi
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Benjamin B Roos
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Jacob J Teske
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Sarah A Wicher
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Andrea McConico
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Christina M Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Venkatachalem Sathish
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Y S Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Gebski EB, Anaspure O, Panettieri RA, Koziol-White CJ. Airway smooth muscle and airway hyperresponsiveness in asthma - mechanisms of airway smooth muscle dysfunction. Minerva Med 2021; 113:4-16. [PMID: 33496164 DOI: 10.23736/s0026-4806.21.07283-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Eric B Gebski
- Drexel College of Arts and Sciences, Drexel University, Philadelphia, PA, USA
| | - Omkar Anaspure
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, NJ, USA
| | - Reynold A Panettieri
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, NJ, USA
| | - Cynthia J Koziol-White
- Rutgers Institute for Translational Medicine and Science, Rutgers University, New Brunswick, NJ, USA -
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Roos BB, Teske JJ, Bhallamudi S, Pabelick CM, Sathish V, Prakash YS. Neurotrophin Regulation and Signaling in Airway Smooth Muscle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1304:109-121. [PMID: 34019266 PMCID: PMC11042712 DOI: 10.1007/978-3-030-68748-9_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Structural and functional aspects of bronchial airways are key throughout life and play critical roles in diseases such as asthma. Asthma involves functional changes such as airway irritability and hyperreactivity, as well as structural changes such as enhanced cellular proliferation of airway smooth muscle (ASM), epithelium, and fibroblasts, and altered extracellular matrix (ECM) and fibrosis, all modulated by factors such as inflammation. There is now increasing recognition that disease maintenance following initial triggers involves a prominent role for resident nonimmune airway cells that secrete growth factors with pleiotropic autocrine and paracrine effects. The family of neurotrophins may be particularly relevant in this regard. Long recognized in the nervous system, classical neurotrophins such as brain-derived neurotrophic factor (BDNF) and nonclassical ligands such as glial-derived neurotrophic factor (GDNF) are now known to be expressed and functional in non-neuronal systems including lung. However, the sources, targets, regulation, and downstream effects are still under investigation. In this chapter, we discuss current state of knowledge and future directions regarding BDNF and GDNF in airway physiology and on pathophysiological contributions in asthma.
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Affiliation(s)
- Benjamin B Roos
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jacob J Teske
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sangeeta Bhallamudi
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Christina M Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Venkatachalem Sathish
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Y S Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA.
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
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Goldsteen PA, Dolga AM, Gosens R. Advanced Modeling of Peripheral Neuro-Effector Communication and -Plasticity. Physiology (Bethesda) 2020; 35:348-357. [PMID: 32783607 DOI: 10.1152/physiol.00010.2020] [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] [Indexed: 12/28/2022] Open
Abstract
The peripheral nervous system (PNS) plays crucial roles in physiology and disease. Neuro-effector communication and neuroplasticity of the PNS are poorly studied, since suitable models are lacking. The emergence of human pluripotent stem cells (hPSCs) has great promise to resolve this deficit. hPSC-derived PNS neurons, integrated into organ-on-a-chip systems or organoid cultures, allow co-cultures with cells of the local microenvironment to study neuro-effector interactions and to probe mechanisms underlying neuroplasticity.
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Affiliation(s)
- Pien A Goldsteen
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.,GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Amalia M Dolga
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.,GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Reinoud Gosens
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.,GRIAC Research Institute, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Ganguly A, Martin RJ. Vulnerability of the developing airway. Respir Physiol Neurobiol 2019; 270:103263. [PMID: 31386914 DOI: 10.1016/j.resp.2019.103263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/02/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022]
Abstract
Longer term respiratory morbidity is a frequent concern for former preterm infants. Increased airway reactivity and wheezing disorders are extremely common in this population, both in infants who meet diagnostic criteria for bronchopulmonary dysplasia [BPD], and in the absence of this diagnosis. It is, therefore, imperative to gain a better understanding of normal and abnormal postnatal development of the immature airway. Airway hyperreactivity may be secondary to abnormal bronchoalveolar attachments in the face of parenchymal lung injury, or secondary to an imbalance between constrictor and dilator neural pathways. Finally, the airway itself may undergo functional and/or structural changes, including increased airway smooth muscle mass, and changes in airway extracellular matrix which may, in turn, modulate downstream signaling pathways to hyperoxia or pressure exposed vulnerable airways.
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Affiliation(s)
- Abhrajit Ganguly
- Rainbow Babies & Children's Hospital, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Suite RBC 3100, Cleveland, OH 44106-6010, United States.
| | - Richard J Martin
- Rainbow Babies & Children's Hospital, Case Western Reserve University School of Medicine, 11100 Euclid Avenue, Suite RBC 3100, Cleveland, OH 44106-6010, United States.
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Britt RD, Thompson MA, Wicher SA, Manlove LJ, Roesler A, Fang YH, Roos C, Smith L, Miller JD, Pabelick CM, Prakash YS. Smooth muscle brain-derived neurotrophic factor contributes to airway hyperreactivity in a mouse model of allergic asthma. FASEB J 2019; 33:3024-3034. [PMID: 30351991 PMCID: PMC6338659 DOI: 10.1096/fj.201801002r] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 10/01/2018] [Indexed: 01/14/2023]
Abstract
Recent studies have demonstrated an effect of neurotrophins, particularly brain-derived neurotrophic factor (BDNF), on airway contractility [ via increased airway smooth muscle (ASM) intracellular calcium [Ca2+]i] and remodeling (ASM proliferation and extracellular matrix formation) in the context of airway disease. In the present study, we examined the role of BDNF in allergen-induced airway inflammation using 2 transgenic models: 1) tropomyosin-related kinase B (TrkB) conditional knockin (TrkBKI) mice allowing for inducible, reversible disruption of BDNF receptor kinase activity by administration of 1NMPP1, a PP1 derivative, and 2) smooth muscle-specific BDNF knockout (BDNFfl/fl/SMMHC11Cre/0) mice. Adult mice were intranasally challenged with PBS or mixed allergen ( Alternaria alternata, Aspergillus fumigatus, house dust mite, and ovalbumin) for 4 wk. Our data show that administration of 1NMPP1 in TrkBKI mice during the 4-wk allergen challenge blunted airway hyperresponsiveness (AHR) and reduced fibronectin mRNA expression in ASM layers but did not reduce inflammation per se. Smooth muscle-specific deletion of BDNF reduced AHR and blunted airway fibrosis but did not significantly alter airway inflammation. Together, our novel data indicate that TrkB signaling is a key modulator of AHR and that smooth muscle-derived BDNF mediates these effects during allergic airway inflammation.-Britt, R. D., Jr., Thompson, M. A., Wicher, S. A., Manlove, L. J., Roesler, A., Fang, Y.-H., Roos, C., Smith, L., Miller, J. D., Pabelick, C. M., Prakash, Y. S. Smooth muscle brain-derived neurotrophic factor contributes to airway hyperreactivity in a mouse model of allergic asthma.
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Affiliation(s)
- Rodney D. Britt
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Michael A. Thompson
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
| | - Sarah A. Wicher
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
| | - Logan J. Manlove
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
| | - Anne Roesler
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
| | - Yun-Hua Fang
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Carolyn Roos
- Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | - Leslie Smith
- Department of Surgery, Mayo Clinic, Rochester, MN, USA
| | | | - Christina M. Pabelick
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
| | - Y. S. Prakash
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA; and
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Hypoxia and Local Inflammation in Pulmonary Artery Structure and Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 967:325-334. [PMID: 29047096 DOI: 10.1007/978-3-319-63245-2_20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hypoxia is recognized as a contributor to pulmonary vascular diseases such as pulmonary hypertension. Hypoxia-induced inflammatory changes can enhance structural and functional changes in pulmonary artery (PA) in the context of PH. Accordingly, understanding how hypoxia and inflammation are linked in the context of pulmonary artery structure and function could be relevant towards development of novel therapies for PH. In this regard, factors such as thymic stromal lymphopoietin (TSLP), an inflammatory cytokine, and brain-derived neurotrophic factor (BDNF), a neurotrophin, have been found critical for nonvascular systems such as airway and asthma. While TSLP canonically affects the immune system, in nonvascular systems, noncanonical effects such as altered [Ca2+]i and cell proliferation have been noted: aspects also relevant to the PA, where there is currently little to no data. Similarly, better known in the nervous system, there is increasing evidence that BDNF is locally produced by structural cells of the airway and can contribute to asthma pathophysiology. In this chapter, we summarize the potential relevance of factors such as TSLP and BDNF to the PA and in the context of hypoxia influences towards development of PH. We focus on cell sources and targets such as PA endothelial cells (PAECs) and smooth muscle cells (PASMCs), and the effects of TSLP or BDNF on intracellular Ca2+ responses to vasoconstrictor agonist, cell proliferation, and potential signaling cascades involved.
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13
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Abstract
PURPOSE OF REVIEW Asthma is a chronic airway disease that affects more than 300 million people worldwide. Current treatment focuses on symptomatic relief by temporally dampening inflammation and relaxing the airway. Novel combative strategies against asthma and hopefully a cure are yet to be developed. The goal of this review is to summarize recent literature on neurotrophins (NTs) in experimental models and clinical settings of asthma research. RECENT FINDINGS We highlight studies of early phases of asthma that collectively reveal a profound impact of elevated NT levels following initial detrimental insults on long-term airway dysfunction. We hope this review will foster insights into the complex interaction between NTs, nerves, immune cells, and airway structural cells during a critical time window of development and disease susceptibility. Future studies are required to better understand the role of NTs in asthma pathophysiology and to evaluate whether NTs and their receptors may serve as new drug targets.
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Affiliation(s)
- Juliana Barrios
- The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Xingbin Ai
- Division of Pulmonary and Critical Care Medicine, Brigham & Women's Hospital, Boston, MA, 02115, USA.
- Pulmonary and Critical Care Medicine, Brigham & Women's Hospital, Thorn Building, Rm. 905, 75 Francis Street, Boston, MA, 02115, USA.
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14
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AL-QUDAH M, SHAMMALA DA, AL-DWAIRI A, AL-SHBOUL O, MUSTAFA AG. Dextran Sodium Sulphate (DSS)-Induced Colitis Alters the Expression of Neurotrophins in Smooth Muscle Cells of Rat Colon. Physiol Res 2017; 66:1009-1020. [DOI: 10.33549/physiolres.933465] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Neurotrophins are present in the gastrointestinal tract where they participate in the survival and growth of enteric neurons, augmentation of enteric circuits, elevation of colonic myoelectrical activity and also in different aspects of colitis. Previous studies largely focused on the role of neural and mucosal neurotrophins in gut inflammation. The expression of neurotrophins in colonic smooth muscle cells (SMCs) and the interactions of this potential source with colitis has not been studied in the gut. The expression of NGF, BDNF, NT-3 and NT-4 in SMCs from longitudinal and circular muscle layers of rat colon from normal and dextran sodium sulphate (DSS)-induced colitis rats was measured by ELISA. NGF, BDNF, NT-3 and NT-4 are differentially expressed in both longitudinal and circular SMCs, where the expressions of BDNF and NT-4 proteins were greater in SMCs from the longitudinal muscle layer than from the circular muscle layer, while NGF protein expression was greater in circular SMCs and NT-3 expression was equal in cells from both muscle layers. Induction of colitis with DSS significantly alters neurotrophins expression pattern in colonic SMCs. NGF levels upregulated in circular SMCs. BDNF level was increased in DSS-induced colitis in longitudinal SMCs. NGF, NT-3 and NT-4 levels were downregulated in longitudinal SMCs of DSS-induced colitis rats' colon. Disturbances of neurotrophins expression in SMCs resulted from colitis might account for the structural and functional changes in inflammatory bowel disease (IBD) such as loss of innervation and characteristic hypercontractility of longitudinal muscle in IBD.
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Affiliation(s)
- M. AL-QUDAH
- Department of Physiology, Jordan University of Science and Technology, Irbid, Jordan
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15
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Freeman MR, Sathish V, Manlove L, Wang S, Britt RD, Thompson MA, Pabelick CM, Prakash YS. Brain-derived neurotrophic factor and airway fibrosis in asthma. Am J Physiol Lung Cell Mol Physiol 2017; 313:L360-L370. [PMID: 28522569 DOI: 10.1152/ajplung.00580.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/17/2017] [Accepted: 05/11/2017] [Indexed: 12/31/2022] Open
Abstract
Airway remodeling in asthma driven by inflammation involves proliferation of epithelial cells and airway smooth muscle (ASM), as well as enhanced extracellular matrix (ECM) generation and deposition, i.e., fibrosis. Accordingly, understanding profibrotic mechanisms is important for developing novel therapeutic strategies in asthma. Recent studies, including our own, have suggested a role for locally produced growth factors such as brain-derived neurotrophic factor (BDNF) in mediating and modulating inflammation effects. In this study, we explored the profibrotic influence of BDNF in the context of asthma by examining expression, activity, and deposition of ECM proteins in primary ASM cells isolated from asthmatic vs. nonasthmatic patients. Basal BDNF expression and secretion, and levels of the high-affinity BDNF receptor TrkB, were higher in asthmatic ASM. Exogenous BDNF significantly increased ECM production and deposition, especially of collagen-1 and collagen-3 (less so fibronectin) and the activity of matrix metalloproteinases (MMP-2, MMP-9). Exposure to the proinflammatory cytokine TNFα significantly increased BDNF secretion, particularly in asthmatic ASM, whereas no significant changes were observed with IL-13. Chelation of BDNF using TrkB-Fc reversed TNFα-induced increase in ECM deposition. Conditioned media from asthmatic ASM enhanced ECM generation in nonasthmatic ASM, which was blunted by BDNF chelation. Inflammation-induced changes in MMP-2, MMP-9, and tissue inhibitor metalloproteinases (TIMP-1, TIMP-2) were reversed in the presence of TrkB-Fc. These novel data suggest ASM as an inflammation-sensitive source of BDNF within human airways, with autocrine effects on fibrosis relevant to asthma.
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Affiliation(s)
- Michelle R Freeman
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Venkatachalem Sathish
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
| | - Logan Manlove
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Shengyu Wang
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Respiratory Medicine, First Affiliated Hospital of Xi'an Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Rodney D Britt
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Michael A Thompson
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Christina M Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
| | - Y S Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota; .,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota; and
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16
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Yuan Q, Sun L, Yu H, An C. Human microvascular endothelial cell promotes the development of dorsal root ganglion neurons via BDNF pathway in a co-culture system. Biosci Biotechnol Biochem 2017; 81:1335-1342. [PMID: 28394221 DOI: 10.1080/09168451.2017.1313695] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Our previous study found that co-culture with human vascular endothelial cells (HMVECs) is beneficial for dorsal root ganglion cells (DRGCs). The goal of the present study is to investigate whether co-culture with HMVECs could promote the development of DRGCs, and whether this effect is induced by the secretion of BDNF by HMVECs. DRGCs were mono-cultured, co-cultured with HMVECs or co-cultured with HMVECs that pre-transfected with BDNF siRNA, the expression of neurite formation and branching factors were determined. The results showed that transfecting with BDNF siRNA inhibited BDNF expression and reduced BDNF secretion. Co-culture with HMVECs increased the expression of Etv4, Etv5, FN-L, FN-M, and GAP-43 in DRGCs that accompanied by the activation of ERK pathway. However, these changes were all reversed by the inhibition of BDNF in HMVECs. In conclusion, our data demonstrate that HMVECs potentiated DRGCs development at least partly by the secretion of BDNF in the co-culture system.
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Affiliation(s)
- Quan Yuan
- a Department of Orthopedics , Shengjing Hospital of China Medical University , Shenyang , People's Republic of China
| | - Li Sun
- b Department of Nephrology , The First Affiliated Hospital of China Medical University , Shenyang , People's Republic of China
| | - Honghao Yu
- a Department of Orthopedics , Shengjing Hospital of China Medical University , Shenyang , People's Republic of China
| | - Chunhou An
- a Department of Orthopedics , Shengjing Hospital of China Medical University , Shenyang , People's Republic of China
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17
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Aravamudan B, Goorhouse KJ, Unnikrishnan G, Thompson MA, Pabelick CM, Hawse JR, Prakash YS, Sathish V. Differential Expression of Estrogen Receptor Variants in Response to Inflammation Signals in Human Airway Smooth Muscle. J Cell Physiol 2017; 232:1754-1760. [PMID: 27808402 DOI: 10.1002/jcp.25674] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 12/16/2022]
Abstract
The prevalence of asthma is higher in pre-pubescent and aging males, and in post-pubertal females, strongly indicating that sex steroids (especially estrogen) may be an important modulator in lung disease. We recently demonstrated that airway smooth muscle (ASM) expresses both alpha and beta forms of the estrogen receptor (ERα and ERβ) in males and females, and that these receptors regulate intracellular [Ca2+ ] and ASM contractility. Although both ERα and ERβ have multiple splice variants, it is unclear if and how the expression of these variants is modulated under conditions such as chronic inflammation/asthma. In order to test the hypothesis that the differential expression of ERα and ERβ variants contributes to the pathogenesis of asthma, we profiled the expression of various ERα and ERβ genes in asthmatic and inflamed (TNFα- or IL-13-treated) ASM. Gene expression was assessed at both the mRNA and protein levels in asthmatic ASM cells or non-asthmatic cells treated with TNFα (20 ng/ml) or IL-13 (50 ng/ml). We observed marked variation in the expression of ER isoforms in response to inflammatory stimuli, and in non-asthmatic versus asthmatic ASM. Changes in protein levels of ERα and ERβ corresponded with the observed differential mRNA patterns. Pharmacological studies implicate cytosolic (p42/44 MAPK and PI3 K) and nuclear (NFκB, STAT6, and AP-1) signaling pathways as putative mechanisms that mediate and/or regulate effects of inflammation on ER expression. We conclude that variations in ASM ER expression profiles occur with inflammation and that ER variants could contribute to estrogen signaling in airway diseases such as asthma. J. Cell. Physiol. 232: 1754-1760, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bharathi Aravamudan
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | | | | | - Michael A Thompson
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Christina M Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - John R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
| | - Y S Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Venkatachalem Sathish
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota.,Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota
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18
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Aravamudan B, Thompson M, Sieck GC, Vassallo R, Pabelick CM, Prakash YS. Functional Effects of Cigarette Smoke-Induced Changes in Airway Smooth Muscle Mitochondrial Morphology. J Cell Physiol 2016; 232:1053-1068. [PMID: 27474898 DOI: 10.1002/jcp.25508] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 07/29/2016] [Indexed: 12/16/2022]
Abstract
Long-term exposure to cigarette smoke (CS) triggers airway hyperreactivity and remodeling, effects that involve airway smooth muscle (ASM). We previously showed that CS destabilizes the networked morphology of mitochondria in human ASM by regulating the expression of mitochondrial fission and fusion proteins via multiple signaling mechanisms. Emerging data link regulation of mitochondrial morphology to cellular structure and function. We hypothesized that CS-induced changes in ASM mitochondrial morphology detrimentally affect mitochondrial function, leading to CS effects on contractility and remodeling. Here, ASM cells were exposed to 1% cigarette smoke extract (CSE) for 48 h to alter mitochondrial fission/fusion, or by inhibiting the fission protein Drp1 or the fusion protein Mfn2. Mitochondrial function was assessed via changes in bioenergetics or altered rates of proliferation and apoptosis. Our results indicate that both exposure to CS and inhibition of mitochondrial fission/fusion proteins affect mitochondrial function (i.e., energy metabolism, proliferation, and apoptosis) in ASM cells. In vivo, the airways in mice chronically exposed to CS are thickened and fibrotic, and the expression of proteins involved in mitochondrial function is dramatically altered in the ASM of these mice. We conclude that CS-induced changes in mitochondrial morphology (fission/fusion balance) correlate with mitochondrial function, and thus may control ASM proliferation, which plays a central role in airway health. J. Cell. Physiol. 232: 1053-1068, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bharathi Aravamudan
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Michael Thompson
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Gary C Sieck
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Robert Vassallo
- Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Christina M Pabelick
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Y S Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota.,Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
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19
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Aravamudan B, Thompson MA, Pabelick CM, Prakash YS. Mechanisms of BDNF regulation in asthmatic airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2016; 311:L270-9. [PMID: 27317689 DOI: 10.1152/ajplung.00414.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 06/09/2016] [Indexed: 12/17/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a neurotrophin produced by airway smooth muscle (ASM), enhances inflammation effects on airway contractility, supporting the idea that locally produced growth factors influence airway diseases such as asthma. We endeavored to dissect intrinsic mechanisms regulating endogenous, as well as inflammation (TNF-α)-induced BDNF secretion in ASM of nonasthmatic vs. asthmatic humans. We focused on specific Ca(2+) regulation- and inflammation-related signaling cascades and quantified BDNF secretion. We find that TNF-α enhances BDNF release by ASM cells, via several mechanisms relevant to asthma, including transient receptor potential channels TRPC3 and TRPC6 (but not TRPC1), ERK 1/2, PI3K, PLC, and PKC cascades, Rho kinase, and transcription factors cAMP response element binding protein and nuclear factor of activated T cells. Basal BDNF expression and secretion are elevated in asthmatic ASM and increase further with TNF-α exposure, involving many of these regulatory mechanisms. We conclude that airway BDNF secretion is regulated at multiple levels, providing a basis for autocrine effects of BDNF under conditions of inflammation and disease, with potential downstream influences on contractility and remodeling.
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Affiliation(s)
| | | | - Christina M Pabelick
- Departments of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Y S Prakash
- Departments of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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20
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Thompson MA, Britt RD, Kuipers I, Stewart A, Thu J, Pandya HC, MacFarlane P, Pabelick CM, Martin RJ, Prakash YS. cAMP-mediated secretion of brain-derived neurotrophic factor in developing airway smooth muscle. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:2506-14. [PMID: 26112987 PMCID: PMC4558218 DOI: 10.1016/j.bbamcr.2015.06.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 05/28/2015] [Accepted: 06/20/2015] [Indexed: 01/12/2023]
Abstract
Moderate hyperoxic exposure in preterm infants contributes to subsequent airway dysfunction and to risk of developing recurrent wheeze and asthma. The regulatory mechanisms that can contribute to hyperoxia-induced airway dysfunction are still under investigation. Recent studies in mice show that hyperoxia increases brain-derived neurotrophic factor (BDNF), a growth factor that increases airway smooth muscle (ASM) proliferation and contractility. We assessed the mechanisms underlying effects of moderate hyperoxia (50% O2) on BDNF expression and secretion in developing human ASM. Hyperoxia increased BDNF secretion, but did not alter endogenous BDNF mRNA or intracellular protein levels. Exposure to hyperoxia significantly increased [Ca2+]i responses to histamine, an effect blunted by the BDNF chelator TrkB-Fc. Hyperoxia also increased ASM cAMP levels, associated with reduced PDE4 activity, but did not alter protein kinase A (PKA) activity or adenylyl cyclase mRNA levels. However, 50% O2 increased expression of Epac2, which is activated by cAMP and can regulate protein secretion. Silencing RNA studies indicated that Epac2, but not Epac1, is important for hyperoxia-induced BDNF secretion, while PKA inhibition did not influence BDNF secretion. In turn, BDNF had autocrine effects of enhancing ASM cAMP levels, an effect inhibited by TrkB and BDNF siRNAs. Together, these novel studies suggest that hyperoxia can modulate BDNF secretion, via cAMP-mediated Epac2 activation in ASM, resulting in a positive feedback effect of BDNF-mediated elevation in cAMP levels. The potential functional role of this pathway is to sustain BDNF secretion following hyperoxic stimulus, leading to enhanced ASM contractility and proliferation.
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Affiliation(s)
| | - Rodney D Britt
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA
| | - Ine Kuipers
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA
| | - Alecia Stewart
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA
| | - James Thu
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA
| | - Hitesh C Pandya
- Department Pediatrics, University of Leicester, Leicester, UK
| | - Peter MacFarlane
- Department of Pediatrics, Division of Neonatology, Rainbow Babies Children's Hospital, Case Western Reserve University, Cleveland, OH, USA
| | - Christina M Pabelick
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
| | - Richard J Martin
- Department of Pediatrics, Division of Neonatology, Rainbow Babies Children's Hospital, Case Western Reserve University, Cleveland, OH, USA
| | - Y S Prakash
- Department of Anesthesiology Mayo Clinic, Rochester, MN, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
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21
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Hartman W, Helan M, Smelter D, Sathish V, Thompson M, Pabelick CM, Johnson B, Prakash YS. Role of Hypoxia-Induced Brain Derived Neurotrophic Factor in Human Pulmonary Artery Smooth Muscle. PLoS One 2015; 10:e0129489. [PMID: 26192455 PMCID: PMC4507987 DOI: 10.1371/journal.pone.0129489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 05/08/2015] [Indexed: 01/28/2023] Open
Abstract
Background Hypoxia effects on pulmonary artery structure and function are key to diseases such as pulmonary hypertension. Recent studies suggest that growth factors called neurotrophins, particularly brain-derived neurotrophic factor (BDNF), can influence lung structure and function, and their role in the pulmonary artery warrants further investigation. In this study, we examined the effect of hypoxia on BDNF in humans, and the influence of hypoxia-enhanced BDNF expression and signaling in human pulmonary artery smooth muscle cells (PASMCs). Methods and Results 48h of 1% hypoxia enhanced BDNF and TrkB expression, as well as release of BDNF. In arteries of patients with pulmonary hypertension, BDNF expression and release was higher at baseline. In isolated PASMCs, hypoxia-induced BDNF increased intracellular Ca2+ responses to serotonin: an effect altered by HIF1α inhibition or by neutralization of extracellular BDNF via chimeric TrkB-Fc. Enhanced BDNF/TrkB signaling increased PASMC survival and proliferation, and decreased apoptosis following hypoxia. Conclusions Enhanced expression and signaling of the BDNF-TrkB system in PASMCs is a potential mechanism by which hypoxia can promote changes in pulmonary artery structure and function. Accordingly, the BDNF-TrkB system could be a key player in the pathogenesis of hypoxia-induced pulmonary vascular diseases, and thus a potential target for therapy.
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Affiliation(s)
- William Hartman
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
- * E-mail:
| | - Martin Helan
- International Clinical Research Center, Department of Cardiovascular Diseases, St. Anne's University Hospital, Brno, Czech Republic
- Department of Anesthesiology and Intensive Care, St. Anne's University Hospital, Masaryk University, Brno, Czech Republic
| | - Dan Smelter
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
| | - Venkatachalem Sathish
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
| | - Michael Thompson
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
| | - Christina M. Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
| | - Bruce Johnson
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
- Department of Internal Medicine, Division of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
| | - Y. S. Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, 55905, United States of America
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22
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Yarova PL, Stewart AL, Sathish V, Britt RD, Thompson MA, P Lowe AP, Freeman M, Aravamudan B, Kita H, Brennan SC, Schepelmann M, Davies T, Yung S, Cholisoh Z, Kidd EJ, Ford WR, Broadley KJ, Rietdorf K, Chang W, Bin Khayat ME, Ward DT, Corrigan CJ, T Ward JP, Kemp PJ, Pabelick CM, Prakash YS, Riccardi D. Calcium-sensing receptor antagonists abrogate airway hyperresponsiveness and inflammation in allergic asthma. Sci Transl Med 2015; 7:284ra60. [PMID: 25904744 DOI: 10.1126/scitranslmed.aaa0282] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/24/2015] [Indexed: 12/27/2022]
Abstract
Airway hyperresponsiveness and inflammation are fundamental hallmarks of allergic asthma that are accompanied by increases in certain polycations, such as eosinophil cationic protein. Levels of these cations in body fluids correlate with asthma severity. We show that polycations and elevated extracellular calcium activate the human recombinant and native calcium-sensing receptor (CaSR), leading to intracellular calcium mobilization, cyclic adenosine monophosphate breakdown, and p38 mitogen-activated protein kinase phosphorylation in airway smooth muscle (ASM) cells. These effects can be prevented by CaSR antagonists, termed calcilytics. Moreover, asthmatic patients and allergen-sensitized mice expressed more CaSR in ASMs than did their healthy counterparts. Indeed, polycations induced hyperreactivity in mouse bronchi, and this effect was prevented by calcilytics and absent in mice with CaSR ablation from ASM. Calcilytics also reduced airway hyperresponsiveness and inflammation in allergen-sensitized mice in vivo. These data show that a functional CaSR is up-regulated in asthmatic ASM and targeted by locally produced polycations to induce hyperresponsiveness and inflammation. Thus, calcilytics may represent effective asthma therapeutics.
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Affiliation(s)
- Polina L Yarova
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Alecia L Stewart
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Rodney D Britt
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Alexander P P Lowe
- Division of Pharmacology, Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3XF, UK
| | - Michelle Freeman
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Hirohito Kita
- Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Sarah C Brennan
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | | | - Thomas Davies
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Sun Yung
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Zakky Cholisoh
- Division of Pharmacology, Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3XF, UK
| | - Emma J Kidd
- Division of Pharmacology, Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3XF, UK
| | - William R Ford
- Division of Pharmacology, Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3XF, UK
| | - Kenneth J Broadley
- Division of Pharmacology, Cardiff University, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF10 3XF, UK
| | - Katja Rietdorf
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA, UK
| | - Wenhan Chang
- Department of Medicine, UCSF School of Medicine, San Francisco, CA 94143, USA
| | - Mohd E Bin Khayat
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Donald T Ward
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | | | - Jeremy P T Ward
- Division of Asthma, Allergy and Lung Biology, King's College London, London SE1 9RT, UK
| | - Paul J Kemp
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | | | - Y S Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905, USA.
| | - Daniela Riccardi
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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23
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Mantilla CB, Stowe JM, Sieck DC, Ermilov LG, Greising SM, Zhang C, Shokat KM, Sieck GC. TrkB kinase activity maintains synaptic function and structural integrity at adult neuromuscular junctions. J Appl Physiol (1985) 2014; 117:910-20. [PMID: 25170066 DOI: 10.1152/japplphysiol.01386.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of the tropomyosin-related kinase receptor B (TrkB) by brain-derived neurotrophic factor acutely regulates synaptic transmission at adult neuromuscular junctions (NMJs). The role of TrkB kinase activity in the maintenance of NMJ function and structure at diaphragm muscle NMJs was explored using a chemical-genetic approach that permits reversible inactivation of TrkB kinase activity in TrkB(F616A) mice by 1NMPP1. Inhibiting TrkB kinase activity for 7 days resulted in significant, yet reversible, impairments in neuromuscular transmission at diaphragm NMJs. Neuromuscular transmission failure following 2 min of repetitive phrenic nerve stimulation increased from 42% in control to 59% in 1NMPP1-treated TrkB(F616A) mice (P = 0.010). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment improved neuromuscular transmission (P = 0.006). Electrophysiological measurements at individual diaphragm NMJs documented lack of differences in quantal content in control and 1NMPP1-treated mice (P = 0.845). Morphological changes at diaphragm NMJs were modest following inhibition and recovery of TrkB kinase activity. Three-dimensional reconstructions of diaphragm NMJs revealed no differences in volume at motor end plates (labeled by α-bungarotoxin; P = 0.982) or presynaptic terminals (labeled by synaptophysin; P = 0.515). Inhibition of TrkB kinase activity by 1NMPP1 resulted in more compact NMJs, with increased apposition of presynaptic terminals and motor end plates (P = 0.017) and reduced fragmentation of motor end plates (P = 0.005). Recovery of TrkB kinase activity following withdrawal of 1NMPP1 treatment resulted in postsynaptic remodeling likely reflecting increased gutter depth (P = 0.007), without significant presynaptic changes. These results support an essential role for TrkB kinase activity in maintaining synaptic function and structural integrity at NMJs in the adult mouse diaphragm muscle.
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Affiliation(s)
- Carlos B Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota; and
| | - Jessica M Stowe
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Dylan C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Leonid G Ermilov
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Sarah M Greising
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Chao Zhang
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California
| | - Kevan M Shokat
- Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, Minnesota; and
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Aravamudan B, Kiel A, Freeman M, Delmotte P, Thompson M, Vassallo R, Sieck GC, Pabelick CM, Prakash YS. Cigarette smoke-induced mitochondrial fragmentation and dysfunction in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2014; 306:L840-54. [PMID: 24610934 DOI: 10.1152/ajplung.00155.2013] [Citation(s) in RCA: 137] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The balance between mitochondrial fission and fusion is crucial for mitochondria to perform its normal cellular functions. We hypothesized that cigarette smoke (CS) disrupts this balance and enhances mitochondrial dysfunction in the airway. In nonasthmatic human airway smooth muscle (ASM) cells, CS extract (CSE) induced mitochondrial fragmentation and damages their networked morphology in a concentration-dependent fashion, via increased expression of mitochondrial fission protein dynamin-related protein 1 (Drp1) and decreased fusion protein mitofusin (Mfn) 2. CSE effects on Drp1 vs. Mfn2 and mitochondrial network morphology involved reactive oxygen species (ROS), activation of extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt), protein kinase C (PKC) and proteasome pathways, as well as transcriptional regulation via factors such as NF-κB and nuclear erythroid 2-related factor 2. Inhibiting Drp1 prevented CSE effects on mitochondrial networks and ROS generation, whereas blocking Mfn2 had the opposite, detrimental effect. In ASM from asmatic patients, mitochondria exhibited substantial morphological defects at baseline and showed increased Drp1 but decreased Mfn2 expression, with exacerbating effects of CSE. Overall, these results highlight the importance of mitochondrial networks and their regulation in the context of cellular changes induced by insults such as inflammation (as in asthma) or CS. Altered mitochondrial fission/fusion proteins have a further potential to influence parameters such as ROS and cell proliferation and apoptosis relevant to airway diseases.
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Affiliation(s)
- Bharathi Aravamudan
- Division of Anesthesia Research, Dept. of Anesthesiology, 4-184 W. Joseph SMH, Mayo Clinic, Rochester, MN 55905.
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Helan M, Aravamudan B, Hartman WR, Thompson MA, Johnson BD, Pabelick CM, Prakash Y. BDNF secretion by human pulmonary artery endothelial cells in response to hypoxia. J Mol Cell Cardiol 2014; 68:89-97. [PMID: 24462831 PMCID: PMC3977651 DOI: 10.1016/j.yjmcc.2014.01.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/24/2013] [Accepted: 01/14/2014] [Indexed: 12/31/2022]
Abstract
Within human pulmonary artery, neurotrophin growth factors [NTs; e.g. brain-derived neurotrophic factor (BDNF)] and their high-affinity receptors (tropomyosin-related kinase; Trk) and low-affinity receptors p75 neurotrophin receptor (p75NTR) have been reported, but their functional role is incompletely understood. We tested the hypothesis that BDNF is produced by human pulmonary artery endothelial cells (PAECs). In the context of hypoxia as a risk factor for pulmonary hypertension, we examined the effect of hypoxia on BDNF secretion and consequent autocrine effects on pulmonary endothelium. Initial ELISA analysis of circulating BDNF in 30 healthy human volunteers showed that 72 h exposure to high altitude (~11,000 ft, alveolar PO2 = 100 mmHg) results in higher BDNF compared to samples taken at sea level. Separately, in human PAECs exposed for 24h to normoxia vs. hypoxia (1-3% O2), ELISA of extracellular media showed increased BDNF levels. Furthermore, quantitative PCR of PAECs showed 3-fold enhancement of BDNF gene transcription with hypoxia. In PAECs, BDNF induced NO production (measured using an NO-sensitive fluorescent dye DAF2-DA) that was significantly higher under hypoxic conditions, an effect also noted with the TrkB agonist 7,8-DHF. Importantly, hypoxia-induced NO was blunted by neutralization of secreted BDNF using the chimeric TrkB-Fc. Both hypoxia and BDNF increased iNOS (but not eNOS) mRNA expression. In accordance, BDNF enhancement of NO in hypoxia was not blunted by 50 nM L-NAME (eNOS inhibition) but substantially lower with 100 μM L-NAME (eNOS and iNOS inhibition). Hypoxia and BDNF also induced expression of hypoxia inducible factor 1 alpha (HIF-1α), a subunit of the transcription factor HIF-1, and pharmacological inhibition of HIF-1 diminished hypoxia effects on BDNF expression and secretion, and NO production. These results indicate that human PAECs express and secrete BDNF in response to hypoxia via a HIF-1-regulated pathway.
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Affiliation(s)
- Martin Helan
- Department of Anesthesiology, Mayo Clinic, Rochester
- ICRC, International Clinical Research Center, Brno, Czech Republic
- Department of Anesthesiology and Intensive Care, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | | | - William R. Hartman
- Department of Anesthesiology, Mayo Clinic, Rochester
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester
| | | | | | - Christina M. Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester
| | - Y.S. Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester
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Prakash YS, Martin RJ. Brain-derived neurotrophic factor in the airways. Pharmacol Ther 2014; 143:74-86. [PMID: 24560686 DOI: 10.1016/j.pharmthera.2014.02.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/10/2014] [Indexed: 12/13/2022]
Abstract
In addition to their well-known roles in the nervous system, there is increasing recognition that neurotrophins such as brain derived neurotrophic factor (BDNF) as well as their receptors are expressed in peripheral tissues including the lung, and can thus potentially contribute to both normal physiology and pathophysiology of several diseases. The relevance of this family of growth factors lies in emerging clinical data indicating altered neurotrophin levels and function in a range of diseases including neonatal and adult asthma, sinusitis, influenza, and lung cancer. The current review focuses on 1) the importance of BDNF expression and signaling mechanisms in early airway and lung development, critical to both normal neonatal lung function and also its disruption in prematurity and insults such as inflammation and infection; 2) how BDNF, potentially derived from airway nerves modulate neurogenic control of airway tone, a key aspect of airway reflexes as well as dysfunctional responses to allergic inflammation; 3) the emerging idea that local BDNF production by resident airway cells such as epithelium and airway smooth muscle can contribute to normal airway structure and function, and to airway hyperreactivity and remodeling in diseases such as asthma. Furthermore, given its pleiotropic effects in the airway, BDNF may be a novel and appealing therapeutic target.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, United States; Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, United States.
| | - Richard J Martin
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH 44106, United States
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27
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Al-Qudah M, Anderson CD, Mahavadi S, Bradley ZL, Akbarali HI, Murthy KS, Grider JR. Brain-derived neurotrophic factor enhances cholinergic contraction of longitudinal muscle of rabbit intestine via activation of phospholipase C. Am J Physiol Gastrointest Liver Physiol 2014; 306:G328-37. [PMID: 24356881 PMCID: PMC3920121 DOI: 10.1152/ajpgi.00203.2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of proteins best known for its role in neuronal survival, differentiation, migration, and synaptic plasticity in central and peripheral neurons. BDNF is also widely expressed in nonneuronal tissues including the gastrointestinal tract. The role of BDNF in intestinal smooth muscle contractility is not well defined. The aim of this study was to identify the role of BDNF in carbachol (CCh)- and substance P (SP)-induced contraction of intestinal longitudinal smooth muscle. BDNF, selective tropomyosin-related kinase B (TrkB) receptor agonists, and pharmacological inhibitors of signaling pathways were examined for their effects on contraction of rabbit intestinal longitudinal muscle strips induced by CCh and SP. BDNF activation of intracellular signaling pathways was examined by Western blot in homogenates of muscle strips and isolated muscle cells. One-hour preincubation with BDNF enhanced intestinal muscle contraction induced by CCh but not by SP. The selective synthetic TrkB agonists LM 22A4 and 7,8-dihydroxyflavone produced similar effects to BDNF. The Trk antagonist K-252a, a TrkB antibody but not p75NTR antibody, blocked the effect of BDNF. The enhancement of CCh-induced contraction by BDNF was blocked by the phospholipase C (PLC) antagonist U73122, but not by ERK1/2 or Akt antagonists. Direct measurement in muscle strips and isolated muscle cells showed that BDNF caused phosphorylation of TrkB receptors and PLC-γ, but not ERK1/2 or Akt. We conclude that exogenous BDNF augments the CCh-induced contraction of longitudinal muscle from rabbit intestine by activating TrkB receptors and subsequent PLC activation.
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Affiliation(s)
- M. Al-Qudah
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia; ,3Jordan University of Science and Technology, Irbid, Jordan
| | - C. D. Anderson
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - S. Mahavadi
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - Z. L. Bradley
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - H. I. Akbarali
- 2Department of Pharmacology and Toxicology, VCU Program in Enteric Neuromuscular Sciences (VPENS), School of Medicine, Virginia Commonwealth University, Richmond, Virginia; and
| | - K. S. Murthy
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
| | - J. R. Grider
- 1Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia;
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Prakash YS. Airway smooth muscle in airway reactivity and remodeling: what have we learned? Am J Physiol Lung Cell Mol Physiol 2013; 305:L912-33. [PMID: 24142517 PMCID: PMC3882535 DOI: 10.1152/ajplung.00259.2013] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/12/2013] [Indexed: 12/12/2022] Open
Abstract
It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca(2+)]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM "activity" result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis.
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Affiliation(s)
- Y S Prakash
- Dept. of Anesthesiology, Mayo Clinic, 4-184 W Jos SMH, 200 First St. SW, Rochester, MN 55905.
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29
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Vohra PK, Thompson MA, Sathish V, Kiel A, Jerde C, Pabelick CM, Singh BB, Prakash YS. TRPC3 regulates release of brain-derived neurotrophic factor from human airway smooth muscle. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2953-2960. [PMID: 23899746 DOI: 10.1016/j.bbamcr.2013.07.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 07/21/2013] [Accepted: 07/23/2013] [Indexed: 12/31/2022]
Abstract
Exogenous brain-derived neurotrophic factor (BDNF) enhances Ca(2+) signaling and cell proliferation in human airway smooth muscle (ASM), especially with inflammation. Human ASM also expresses BDNF, raising the potential for autocrine/paracrine effects. The mechanisms by which ASM BDNF secretion occurs are not known. Transient receptor potential channels (TRPCs) regulate a variety of intracellular processes including store-operated Ca(2+) entry (SOCE; including in ASM) and secretion of factors such as cytokines. In human ASM, we tested the hypothesis that TRPC3 regulates BDNF secretion. At baseline, intracellular BDNF was present, and BDNF secretion was detectable by enzyme linked immunosorbent assay (ELISA) of cell supernatants or by real-time fluorescence imaging of cells transfected with GFP-BDNF vector. Exposure to the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) (20ng/ml, 48h) or a mixture of allergens (ovalbumin, house dust mite, Alternaria, and Aspergillus extracts) significantly enhanced BDNF secretion and increased TRPC3 expression. TRPC3 knockdown (siRNA or inhibitor Pyr3; 10μM) blunted BDNF secretion, and prevented inflammation effects. Chelation of extracellular Ca(2+) (EGTA; 1mM) or intracellular Ca(2+) (BAPTA; 5μM) significantly reduced secreted BDNF, as did the knockdown of SOCE proteins STIM1 and Orai1 or plasma membrane caveolin-1. Functionally, secreted BDNF had autocrine effects suggested by phosphorylation of high-affinity tropomyosin-related kinase TrkB receptor, prevented by chelating extracellular BDNF with chimeric TrkB-Fc. These data emphasize the role of TRPC3 and Ca(2+) influx in the regulation of BDNF secretion by human ASM and the enhancing effects of inflammation. Given the BDNF effects on Ca(2+) and cell proliferation, BDNF secretion may contribute to altered airway structure and function in diseases such as asthma.
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Affiliation(s)
- Pawan K Vohra
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Michael A Thompson
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Venkatachalem Sathish
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA; Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Alexander Kiel
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Calvin Jerde
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Christina M Pabelick
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA; Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | - Brij B Singh
- Department of Biochemistry and Molecular Biology, University of North Dakota, 264 Centennial Dr, Grand Forks, ND 58202, USA
| | - Y S Prakash
- Department of Anesthesiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA; Department of Physiology & Biomedical Engineering, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
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Sathish V, Vanoosten SK, Miller BS, Aravamudan B, Thompson MA, Pabelick CM, Vassallo R, Prakash YS. Brain-derived neurotrophic factor in cigarette smoke-induced airway hyperreactivity. Am J Respir Cell Mol Biol 2013; 48:431-8. [PMID: 23258230 DOI: 10.1165/rcmb.2012-0129oc] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Enhanced airway smooth muscle (ASM) contractility contributes to increased resistance to airflow in diseases such as bronchitis and asthma that occur in passive smokers exposed to secondhand smoke. Little information exists on the cellular mechanisms underlying such airway hyperreactivity. Sputum samples of patients with chronic sinusitis, bronchitis, and asthma show increased concentrations of growth factors called neurotrophins, including brain-derived growth factor (BDNF), but their physiological significance remains unknown. In human ASM, we tested the hypothesis that BDNF contributes to increased contractility with cigarette smoke exposure. The exposure of ASM to 1% or 2% cigarette smoke extract (CSE) for 24 hours increased intracellular calcium ([Ca(2+)](i)) responses to histamine, and further potentiated the enhancing effects of a range of BDNF concentrations on such histamine responses. CSE exposure increased the expression of the both high-affinity and low-affinity neurotrophin receptors tropomyosin-related kinase (Trk)-B and p75 pan-neurotrophin receptor, respectively. Quantitative ELISA showed that CSE increased BDNF secretion by human ASM cells. BDNF small interfering (si)RNA and/or the chelation of extracellular BDNF, using TrkB-fragment crystallizable, blunted the effects of CSE on [Ca(2+)](i) responses as well as the CSE enhancement of cell proliferation, whereas TrkB siRNA blunted the effects of CSE on ASM contractility. These data suggest that cigarette smoke is a potent inducer of BDNF and TrkB expression and signaling in ASM, which then contribute to cigarette smoke-induced airway hyperresponsiveness.
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Aravamudan B, Thompson M, Pabelick C, Prakash YS. Brain-derived neurotrophic factor induces proliferation of human airway smooth muscle cells. J Cell Mol Med 2012; 16:812-23. [PMID: 21651720 PMCID: PMC3175295 DOI: 10.1111/j.1582-4934.2011.01356.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Airway diseases such as asthma involve increased airway smooth muscle (ASM) contractility and remodelling via enhanced proliferation. Neurotrophins (NTs) such as brain-derived neurotrophic factor (BDNF), well-known in the nervous system, can regulate Ca2+ signalling, and interact with cytokines in contributing to airway hyperreactivity. In this study, we determined whether and how BDNF regulates human ASM cell proliferation in the presence of inflammation, thus testing its potential role in airway remodelling. Cells were treated with 10 nM BDNF, 25 ng/ml tumour necrosis factor (TNF-α) or interleukin-13 (IL-13), or 10 ng/ml platelet-derived growth factor (PDGF). Proliferation was measured using CyQuant dye, with immunoblotting of cell cycle proteins predicted to change with proliferation. Forty-eight hours of BDNF enhanced ASM proliferation to ∼50% of that by PDGF or cytokines. Transfection with small interfering RNAs (siRNAs) targeting high-affinity tropomyosin-related kinase B receptor abolished BDNF effects on proliferation, whereas low-affinity 75 kD neurotrophin receptor (p75NTR) siRNA had no effect. Systematic pharmacologic inhibition of different components of ERK1/2 and PI3K/Akt1 pathways blunted BDNF or TNF-α–induced proliferation. BDNF also induced IκB phosphorylation and nuclear translocation of p50 and p65 NF-κB subunits, with electron mobility shift assay confirmation of NF-κB binding to consensus DNA sequence. These results demonstrate that NTs such as BDNF can enhance human ASM cell proliferation by activating proliferation-specific signalling pathways and a versatile transcription factor such as NF-κB, which are common to cytokines and growth factors involved in asthma.
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Affiliation(s)
- Bharathi Aravamudan
- Department of Anesthesiology, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Abcejo AJ, Sathish V, Smelter DF, Aravamudan B, Thompson MA, Hartman WR, Pabelick CM, Prakash YS. Brain-derived neurotrophic factor enhances calcium regulatory mechanisms in human airway smooth muscle. PLoS One 2012; 7:e44343. [PMID: 22952960 PMCID: PMC3430656 DOI: 10.1371/journal.pone.0044343] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 08/02/2012] [Indexed: 11/22/2022] Open
Abstract
Neurotrophins (NTs), which play an integral role in neuronal development and function, have been found in non-neuronal tissue (including lung), but their role is still under investigation. Recent reports show that NTs such as brain-derived neurotrophic factor (BDNF) as well as NT receptors are expressed in human airway smooth muscle (ASM). However, their function is still under investigation. We hypothesized that NTs regulate ASM intracellular Ca2+ ([Ca2+]i) by altered expression of Ca2+ regulatory proteins. Human ASM cells isolated from lung samples incidental to patient surgery were incubated for 24 h (overnight) in medium (control) or 1 nM BDNF in the presence vs. absence of inhibitors of signaling cascades (MAP kinases; PI3/Akt; NFκB). Measurement of [Ca2+]i responses to acetylcholine (ACh) and histamine using the Ca2+ indicator fluo-4 showed significantly greater responses following BDNF exposure: effects that were blunted by pathway inhibitors. Western analysis of whole cell lysates showed significantly higher expression of CD38, Orai1, STIM1, IP3 and RyR receptors, and SERCA following BDNF exposure, effects inhibited by inhibitors of the above cascades. The functional significance of BDNF effects were verified by siRNA or pharmacological inhibition of proteins that were altered by this NT. Overall, these data demonstrate that NTs activate signaling pathways in human ASM that lead to enhanced [Ca2+]i responses via increased regulatory protein expression, thus enhancing airway contractility.
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Affiliation(s)
- Amard J. Abcejo
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Venkatachalem Sathish
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Dan F. Smelter
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Bharathi Aravamudan
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Michael A. Thompson
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - William R. Hartman
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Christina M. Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Y. S. Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Delmotte P, Yang B, Thompson MA, Pabelick CM, Prakash YS, Sieck GC. Inflammation alters regional mitochondrial Ca²+ in human airway smooth muscle cells. Am J Physiol Cell Physiol 2012; 303:C244-56. [PMID: 22673614 DOI: 10.1152/ajpcell.00414.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Regulation of cytosolic Ca(2+) concentration ([Ca(2+)](cyt)) in airway smooth muscle (ASM) is a key aspect of airway contractility and can be modulated by inflammation. Mitochondria have tremendous potential for buffering [Ca(2+)](cyt), helping prevent Ca(2+) overload, and modulating other intracellular events. Here, compartmentalization of mitochondria to different cellular regions may subserve different roles. In the present study, we examined the role of Ca(2+) buffering by mitochondria and mitochondrial Ca(2+) transport mechanisms in the regulation of [Ca(2+)](cyt) in enzymatically dissociated human ASM cells upon exposure to the proinflammatory cytokines TNF-α and IL-13. Cells were loaded simultaneously with fluo-3 AM and rhod-2 AM, and [Ca(2+)](cyt) and mitochondrial Ca(2+) concentration ([Ca(2+)](mito)) were measured, respectively, using real-time two-color fluorescence microscopy in both the perinuclear and distal, perimembranous regions of cells. Histamine induced a rapid increase in both [Ca(2+)](cyt) and [Ca(2+)](mito), with a significant delay in the mitochondrial response. Inhibition of the mitochondrial Na(+)/Ca(2+) exchanger (1 μM CGP-37157) increased [Ca(2+)](mito) responses in perinuclear mitochondria but not distal mitochondria. Inhibition of the mitochondrial uniporter (1 μM Ru360) decreased [Ca(2+)](mito) responses in perinuclear and distal mitochondria. CGP-37157 and Ru360 significantly enhanced histamine-induced [Ca(2+)](cyt). TNF-α and IL-13 both increased [Ca(2+)](cyt), which was associated with decreased [Ca(2+)](mito) in the case of TNF-α but not IL-13. The effects of TNF-α on both [Ca(2+)](cyt) and [Ca(2+)](mito) were affected by CGP-37157 but not by Ru360. Overall, these data demonstrate that in human ASM cells, mitochondria buffer [Ca(2+)](cyt) after agonist stimulation and its enhancement by inflammation. The differential regulation of [Ca(2+)](mito) in different parts of ASM cells may serve to locally regulate Ca(2+) fluxes from intracellular sources versus the plasma membrane as well as respond to differential energy demands at these sites. We propose that such differential mitochondrial regulation, and its disruption, may play a role in airway hyperreactivity in diseases such as asthma, where [Ca(2+)](cyt) is increased.
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Affiliation(s)
- Philippe Delmotte
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota 55905, USA
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Dorsey SG, Lovering RM, Renn CL, Leitch CC, Liu X, Tallon LJ, Sadzewicz LD, Pratap A, Ott S, Sengamalay N, Jones KM, Barrick C, Fulgenzi G, Becker J, Voelker K, Talmadge R, Harvey BK, Wyatt RM, Vernon-Pitts E, Zhang C, Shokat K, Fraser-Liggett C, Balice-Gordon RJ, Tessarollo L, Ward CW. Genetic deletion of trkB.T1 increases neuromuscular function. Am J Physiol Cell Physiol 2011; 302:C141-53. [PMID: 21865582 DOI: 10.1152/ajpcell.00469.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neurotrophin-dependent activation of the tyrosine kinase receptor trkB.FL modulates neuromuscular synapse maintenance and function; however, it is unclear what role the alternative splice variant, truncated trkB (trkB.T1), may have in the peripheral neuromuscular axis. We examined this question in trkB.T1 null mice and demonstrate that in vivo neuromuscular performance and nerve-evoked muscle tension are significantly increased. In vitro assays indicated that the gain-in-function in trkB.T1(-/-) animals resulted specifically from an increased muscle contractility, and increased electrically evoked calcium release. In the trkB.T1 null muscle, we identified an increase in Akt activation in resting muscle as well as a significant increase in trkB.FL and Akt activation in response to contractile activity. On the basis of these findings, we conclude that the trkB signaling pathway might represent a novel target for intervention across diseases characterized by deficits in neuromuscular function.
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Affiliation(s)
- Susan G Dorsey
- University of Maryland Baltimore School of Nursing, Baltimore, Maryland 21201, USA.
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Sathish V, Abcejo AJ, VanOosten SK, Thompson MA, Prakash YS, Pabelick CM. Caveolin-1 in cytokine-induced enhancement of intracellular Ca(2+) in human airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2011; 301:L607-14. [PMID: 21803870 DOI: 10.1152/ajplung.00019.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Diseases such as asthma are characterized by airway hyperresponsiveness. Enhanced airway smooth muscle (ASM) intracellular Ca(2+) ([Ca(2+)](i)) response to agonist stimulation leading to increased airway constriction has been suggested to contribute to airway hyperresponsiveness. Caveolae are flask-shaped plasma membrane invaginations that express the scaffolding protein caveolin and contain multiple proteins important in [Ca(2+)](i) signaling (e.g., agonist receptors, ion channels). We recently demonstrated that caveolae and caveolin-1 are important in [Ca(2+)](i) regulation in human ASM. Proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-13 modulate [Ca(2+)](i) in ASM. We hypothesized that cytokine upregulation of caveolar signaling in ASM contributes to enhanced agonist-induced [Ca(2+)](i) in inflammation. Enzymatically dissociated human ASM cells were exposed to medium (control), 20 ng/ml TNF-α, or 50 ng/ml IL-13 for 24 h. Caveolae-enriched membrane fractions displayed substantial increase in caveolin-1 and -2 expressions by TNF-α and IL-13. Transfection with caveolin-1-mRed DNA substantially accelerated and increased plasma membrane caveolin-1 expression by TNF-α and to a lesser extent by IL-13. Caveolin-1 enhancement was inhibited by nuclear factor-κB and mitogen-activated protein kinase inhibitors. In fura 2-loaded ASM cells, [Ca(2+)](i) responses to 1 μM ACh, 10 μM histamine, or 10 nM bradykinin were all exaggerated by TNF-α as well as IL-13 exposure. However, disruption of caveolae using caveolin-1 suppression via small-interfering RNA resulted in significant blunting of agonist-induced [Ca(2+)](i) responses of vehicle and TNF-α-exposed cells. These functional data were correlated to the presence of TNFR(1) receptor (but not the IL-4/IL-13 receptor) within caveolae. Overall, these results indicate that caveolin-1 plays an important role in airway inflammation by modulating the effect of specific cytokines on [Ca(2+)](i).
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Meuchel LW, Stewart A, Smelter DF, Abcejo AJ, Thompson MA, Zaidi SIA, Martin RJ, Prakash YS. Neurokinin-neurotrophin interactions in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2011; 301:L91-8. [PMID: 21515660 DOI: 10.1152/ajplung.00320.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Neurally derived tachykinins such as substance P (SP) play a key role in modulating airway contractility (especially with inflammation). Separately, the neurotrophin brain-derived neurotrophic factor (BDNF; potentially derived from nerves as well as airway smooth muscle; ASM) and its tropomyosin-related kinase receptor, TrkB, are involved in enhanced airway contractility. In this study, we hypothesized that neurokinins and neurotrophins are linked in enhancing intracellular Ca(2+) concentration ([Ca(2+)](i)) regulation in ASM. In rat ASM cells, 24 h exposure to 10 nM SP significantly increased BDNF and TrkB expression (P < 0.05). Furthermore, [Ca(2+)](i) responses to 1 μM ACh as well as BDNF (30 min) effects on [Ca(2+)](i) regulation were enhanced by prior SP exposure, largely via increased Ca(2+) influx (P < 0.05). The enhancing effect of SP on BDNF signaling was blunted by the neurokinin-2 receptor antagonist MEN-10376 (1 μM, P < 0.05) to a greater extent than the neurokinin-1 receptor antagonist RP-67580 (5 nM). Chelation of extracellular BDNF (chimeric TrkB-F(c); 1 μg/ml), as well as tyrosine kinase inhibition (100 nM K252a), substantially blunted SP effects (P < 0.05). Overnight (24 h) exposure of ASM cells to 50% oxygen increased BDNF and TrkB expression and potentiated both SP- and BDNF-induced enhancement of [Ca(2+)](i) (P < 0.05). These results suggest a novel interaction between SP and BDNF in regulating agonist-induced [Ca(2+)](i) regulation in ASM. The autocrine mechanism we present here represents a new area in the development of bronchoconstrictive reflex response and airway hyperreactive disorders.
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Affiliation(s)
- Lucas W Meuchel
- Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Meuchel LW, Thompson MA, Cassivi SD, Pabelick CM, Prakash YS. Neurotrophins induce nitric oxide generation in human pulmonary artery endothelial cells. Cardiovasc Res 2011; 91:668-76. [PMID: 21498417 DOI: 10.1093/cvr/cvr107] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIMS Members of the growth factor family of neurotrophins [NTs; e.g. brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3)] and their high-affinity receptors (tropomyosin-related kinase; Trk) and low-affinity receptors p75 neurotrophin receptor (p75NTR) have been localized to pulmonary artery (PA) in humans. However, their role is unclear. Based on previous findings of NTs and their receptors within the pulmonary endothelium, we tested the hypothesis that NTs induce nitric oxide (NO) production in pulmonary endothelial cells (ECs), thus contributing to vasodilation. METHODS AND RESULTS In human pulmonary artery ECs loaded with the NO-sensitive fluorescent dye diaminofluorescein-2, both BDNF and NT3 (100 pM, 1 nM, and 10 nM) acutely (<10 min) and substantially increased fluorescence levels in a concentration-dependent fashion (to levels comparable to that induced by 1 μM acetylcholine). NT-induced elevation of NO levels was blunted by the tyrosine kinase inhibitor K252a, the nitric oxide synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester, the Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, and the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. Suppression of TrkB or TrkC expression via siRNA as well as functional blockade of p75NTR prevented NT-induced NO elevation. Both BDNF and NT3 increased phosphorylation of Akt and endothelial NO synthase (eNOS). In endothelium-intact porcine PA rings, NTs increased cGMP and induced vasodilation in pre-contracted arteries. CONCLUSION These results indicate that NTs acutely modulate pulmonary endothelial NO production and contribute to relaxation of the pulmonary vasculature.
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Affiliation(s)
- Lucas W Meuchel
- Department of Physiology, Mayo Clinic College of Medicine, 4-184 W. Jos SMH, Rochester, MN 55905, USA
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Prakash Y, Thompson MA, Meuchel L, Pabelick CM, Mantilla CB, Zaidi S, Martin RJ. Neurotrophins in lung health and disease. Expert Rev Respir Med 2010; 4:395-411. [PMID: 20524922 DOI: 10.1586/ers.10.29] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Neurotrophins (NTs) are a family of growth factors that are well-known in the nervous system. There is increasing recognition that NTs (nerve growth factor, brain-derived neurotrophic factor and NT3) and their receptors (high-affinity TrkA, TrkB and TrkC, and low-affinity p75NTR) are expressed in lung components including the nasal and bronchial epithelium, smooth muscle, nerves and immune cells. NT signaling may be important in normal lung development, developmental lung disease, allergy and inflammation (e.g., rhinitis, asthma), lung fibrosis and even lung cancer. In this review, we describe the current status of our understanding of NT signaling in the lung, with hopes of using aspects of the NT signaling pathway in the diagnosis and therapy of lung diseases.
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Affiliation(s)
- Ys Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Smelter DF, Sathish V, Thompson MA, Pabelick CM, Vassallo R, Prakash YS. Thymic stromal lymphopoietin in cigarette smoke-exposed human airway smooth muscle. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 185:3035-40. [PMID: 20660708 PMCID: PMC3681514 DOI: 10.4049/jimmunol.1000252] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Thymic stromal lymphopoietin (TSLP) is a newly identified IL-7-like cytokine known to be expressed in airway biopsies of patients with asthma and chronic obstructive pulmonary disease. As both diseases may be induced or exacerbated by cigarette smoking, it is possible that TSLP represents an important link between cigarette smoke exposure and inflammatory signaling in the airways. In this regard, TSLP appears to also be expressed in airway smooth muscle (ASM); however, its role is unknown. In the current study, we examined TSLP and the TSLP receptor (TSLP-R) expression and function in human ASM cells under normal conditions and following exposure to cigarette smoke extract (CSE). Western blot analysis of human ASM cells showed significant expression of TSLP and TSLP-R, with increased expression of both by overnight exposure to 1 or 2% CSE. Furthermore, CSE increased TSLP release by ASM. In parallel experiments using enzymatically dissociated human ASM cells loaded with the Ca(2+) indicator fura 2-AM and imaged using fluorescence microscopy, we evaluated the effects of CSE exposure on intracellular Ca(2+) ([Ca(2+)](i)) responses to agonist stimulation. [Ca(2+)](i) responses to histamine were increased with overnight CSE exposure. Exposure to TSLP also resulted in elevated responses, which were blunted by TSLP and TSLP-R Abs. Importantly, the enhancing effects of CSE on [Ca(2+)](i) responses were also blunted by these Abs. These effects were associated with CSE- and TSLP-induced changes in STAT5 phosphorylation. Overall, these novel data suggest that cigarette smoke, TSLP, and ASM are functionally linked and that cigarette smoke-induced increase in airway contractility may be mediated via ASM-derived increases in TSLP signaling.
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Affiliation(s)
- Dan F. Smelter
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905
| | | | | | - Christina M. Pabelick
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
| | | | - Y. S. Prakash
- Department of Anesthesiology, Mayo Clinic, Rochester, MN 55905
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905
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Sciesielski LK, Paliege A, Martinka P, Scholz H. Enhanced pulmonary expression of the TrkB neurotrophin receptor in hypoxic rats is associated with increased acetylcholine-induced airway contractility. Acta Physiol (Oxf) 2009; 197:253-64. [PMID: 19583705 DOI: 10.1111/j.1748-1716.2009.02016.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AIM We have recently reported that hypoxia stimulates transcription of the TrkB neurotrophin receptor in cultured cells via stabilization of hypoxia-inducible factor-1alpha. Here we investigated whether the expression of TrkB and other neurotrophin receptors is oxygen-sensitive also in vivo, and explored the functional consequences of an oxygen-regulated TrkB expression. METHODS Rats were exposed either to 21% O(2) or 8% O(2) for 6 h and TrkB was analysed by reverse transcription real-time PCR, in situ mRNA hybridization, and immunological techniques. The importance of the brain-derived neurotrophic factor (BDNF)-TrkB pathway in the control of mechanical airway function was assessed on isolated tracheal segments from normoxic and hypoxic rats. RESULTS TrkB transcripts were increased approx. 15-fold in the lungs of hypoxic rats, and the respiratory epithelium was identified as the site of enhanced TrkB expression in hypoxia. The TrkB ligand, BDNF, significantly increased the contractile response to acetylcholine (ACh) of isolated tracheal segments from hypoxic but not from normoxic rats. This effect of BDNF was prevented by pre-incubation of the tissue specimens with the tyrosine kinase inhibitor K252a and by mechanical removal of the TrkB containing airway epithelium. Likewise, the nitric oxide (NO) synthase inhibitor l-NAME abrogated the influence of BDNF on ACh-induced contractions of isolated tracheal segments from hypoxic rats. CONCLUSION These results demonstrate that systemic hypoxia stimulates expression of the TrkB neurotrophin receptor in the airway epithelium. Furthermore, activation of TrkB signalling by BDNF in hypoxia enhances mechanical airway contractility to ACh through a mechanism that requires NO.
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Affiliation(s)
- L K Sciesielski
- Institut für Vegetative Physiologie, Charité- Universitätsmedizin Berlin, Berlin, Germany
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Stickland MK, Smith CA, Soriano BJ, Dempsey JA. Sympathetic restraint of muscle blood flow during hypoxic exercise. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1538-46. [PMID: 19297541 DOI: 10.1152/ajpregu.90918.2008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Control of exercising muscle blood flow is a balance between local vasodilatory factors and the increase in global sympathetic vasoconstrictor outflow. Hypoxia has been shown to potentiate the muscle sympathetic nerve response to exercise, potentially limiting the increase in muscle blood flow. Accordingly, we investigated sympathetic restraint to exercising muscle during whole body exercise in hypoxia. Six dogs chronically instrumented with ascending aortic and hindlimb flow probes and a terminal aortic catheter were studied at rest and mild [2.5 miles/h (mph), 5% grade] and moderate (4.0 mph, 10% grade) exercise while breathing room air or hypoxia (Pa(O(2)) approximately 45 mmHg) in the intact control condition and following systemic alpha-adrenergic blockade (phentolamine). Hypoxia caused an increase in cardiac output (CO), hindlimb flow (Flow(L)), and blood pressure (BP), while total (Cond(T)) and hindlimb conductance (Cond(L)) were unchanged at rest and mild exercise but increased with moderate exercise. During both mild and moderate exercise, alpha-blockade in normoxia resulted in significant vasodilation as evidenced by increases in CO (10%), Flow(L) (17%), Cond(T) (33%), Cond(L) (43%), and a decrease in BP (-18%), with the increase in Cond(L) greater than the increase in Cond(T) during mild exercise. Compared with the normoxic response, alpha-blockade in hypoxia during exercise resulted in a significantly greater increase in Cond(T) (59%) and Cond(L) (74%) and a correspondingly greater decrease in BP (-34%) from baseline. These findings indicate that there is considerable hypoxia-induced sympathetic restraint of muscle blood flow during both mild and moderate exercise, which helps to maintain arterial blood pressure in hypoxia.
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Affiliation(s)
- Michael K Stickland
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
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42
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Gonzalez- Alonso J, Mortensen SP. Comments of point:counterpoint: maximal oxygen uptake is/is not limited by a central nervous system governor. J Appl Physiol (1985) 2009; 106:346. [PMID: 19202591 DOI: 10.1152/japplphysiol.zdg-8326.pcpcomm.2008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Prakash YS, Thompson MA, Pabelick CM. Brain-derived neurotrophic factor in TNF-alpha modulation of Ca2+ in human airway smooth muscle. Am J Respir Cell Mol Biol 2009; 41:603-11. [PMID: 19213875 DOI: 10.1165/rcmb.2008-0151oc] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
There is increasing recognition that neurotrophin (NT) signaling occurs in non-neuronal tissues, including airway smooth muscle (ASM). We recently demonstrated that NTs, such as brain-derived neurotrophic factor (BDNF), enhance intracellular Ca2+ ([Ca2+](i)) and force regulation in human ASM. Increased NT expression has been observed in airway diseases, such as asthma and allergy. In the present study, we tested the hypothesis that NTs contribute to inflammation-induced enhancement of ASM contractility. Using human ASM cells and real-time fluorescence [Ca2+](i) imaging, we examined the contribution of the high-affinity tropomyosin-related kinase and low-affinity, pan-NT p75NTR receptors to [Ca2+](i) regulation under control conditions and after exposure to the proinflammatory cytokine TNF-alpha (20 ng/ml). Exposure to TNF-alpha enhanced [Ca2+](i) responses to agonist (acetylcholine, histamine). Exposure to 10 nM BDNF for even 30 minutes substantially and synergistically enhanced TNF-alpha effects on [Ca2+](i) responses to agonist. Small interfering RNA suppression of tropomyosin-related kinase substantially blunted the effect of BDNF on [Ca2+](i) responses to agonist (with greater effect on Ca2+ influx via store-operated Ca2+ entry compared with sarcoplasmic reticulum Ca2+ release) in both control and TNF-alpha-exposed cells. However, p75NTR suppression by small interfering RNA had no significant effect on [Ca2+](i) responses in either cell group. These novel data demonstrate that NTs influence ASM contractility, and suggest a potential role for NTs in airway diseases.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Noakes TD, Marino FE. Last Word on Point:Counterpoint: Maximal oxygen uptake is/is not limited by a central nervous system governor. J Appl Physiol (1985) 2009; 106:347. [DOI: 10.1152/japplphysiol.zdg-8327-pcpcomm.2008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Szikra T, Cusato K, Thoreson WB, Barabas P, Bartoletti TM, Krizaj D. Depletion of calcium stores regulates calcium influx and signal transmission in rod photoreceptors. J Physiol 2008; 586:4859-75. [PMID: 18755743 DOI: 10.1113/jphysiol.2008.160051] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Tonic synapses are specialized for sustained calcium entry and transmitter release, allowing them to operate in a graded fashion over a wide dynamic range. We identified a novel plasma membrane calcium entry mechanism that extends the range of rod photoreceptor signalling into light-adapted conditions. The mechanism, which shares molecular and physiological characteristics with store-operated calcium entry (SOCE), is required to maintain baseline [Ca(2+)](i) in rod inner segments and synaptic terminals. Sustained Ca(2+) entry into rod cytosol is augmented by store depletion, blocked by La(3+) and Gd(3+) and suppressed by organic antagonists MRS-1845 and SKF-96365. Store depletion and the subsequent Ca(2+) influx directly stimulated exocytosis in terminals of light-adapted rods loaded with the activity-dependent dye FM1-43. Moreover, SOCE blockers suppressed rod-mediated synaptic inputs to horizontal cells without affecting presynaptic voltage-operated Ca(2+) entry. Silencing of TRPC1 expression with small interference RNA disrupted SOCE in rods, but had no effect on cone Ca(2+) signalling. Rods were immunopositive for TRPC1 whereas cone inner segments immunostained with TRPC6 channel antibodies. Thus, SOCE modulates Ca(2+) homeostasis and light-evoked neurotransmission at the rod photoreceptor synapse mediated by TRPC1.
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Affiliation(s)
- Tamas Szikra
- Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA 94143, USA
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Lundby C, Robach P, Boushel R, Thomsen JJ, Rasmussen P, Koskolou M, Calbet JAL. Does recombinant human Epo increase exercise capacity by means other than augmenting oxygen transport? J Appl Physiol (1985) 2008; 105:581-7. [DOI: 10.1152/japplphysiol.90484.2008] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was performed to test the hypothesis that administration of recombinant human erythropoietin (rHuEpo) in humans increases maximal oxygen consumption by augmenting the maximal oxygen carrying capacity of blood. Systemic and leg oxygen delivery and oxygen uptake were studied during exercise in eight subjects before and after 13 wk of rHuEpo treatment and after isovolemic hemodilution to the same hemoglobin concentration observed before the start of rHuEpo administration. At peak exercise, leg oxygen delivery was increased from 1,777.0 ± 102.0 ml/min before rHuEpo treatment to 2,079.8 ± 120.7 ml/min after treatment. After hemodilution, oxygen delivery was decreased to the pretreatment value (1,710.3 ± 138.1 ml/min). Fractional leg arterial oxygen extraction was unaffected at maximal exercise; hence, maximal leg oxygen uptake increased from 1,511.0 ± 130.1 ml/min before treatment to 1,793.0 ± 148.7 ml/min with rHuEpo and decreased after hemodilution to 1,428.0 ± 111.6 ml/min. Pulmonary oxygen uptake at peak exercise increased from 3,950.0 ± 160.7 before administration to 4,254.5 ± 178.4 ml/min with rHuEpo and decreased to 4,059.0 ± 161.1 ml/min with hemodilution ( P = 0.22, compared with values before rHuEpo treatment). Blood buffer capacity remained unaffected by rHuEpo treatment and hemodilution. The augmented hematocrit did not compromise peak cardiac output. In summary, in healthy humans, rHuEpo increases maximal oxygen consumption due to augmented systemic and muscular peak oxygen delivery.
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Bennedich Kahn L, Gustafsson LE, Olgart Höglund C. Brain-derived neurotrophic factor enhances histamine-induced airway responses and changes levels of exhaled nitric oxide in guinea pigs in vivo. Eur J Pharmacol 2008; 595:78-83. [PMID: 18700138 DOI: 10.1016/j.ejphar.2008.07.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Revised: 07/16/2008] [Accepted: 07/23/2008] [Indexed: 12/28/2022]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) occurs in elevated levels during airway inflammation, including asthma and hypoxic lung injury, and has been suggested to be associated with airway hyperresponsiveness in these conditions. The aim of the present study was to examine whether airway responses to histamine challenge and levels of exhaled nitric oxide (NO) in vivo might be altered upon BDNF treatment. Pulmonary resistance, lung compliance, insufflation pressure, and levels of exhaled NO were measured in anaesthetized guinea pigs exposed to BDNF prior to challenge with histamine and with intact or inhibited endogenous NO production. BDNF pretreatment significantly enhanced histamine-evoked increase in pulmonary resistance and insufflation pressure, as well as the decrease in lung compliance. BDNF markedly accentuated the reduction in exhaled NO following histamine challenge. In animals with inhibited endogenous NO production BDNF induced a significantly earlier histamine-evoked increase in airway responses. The present data show that BDNF can induce an augmentation of histamine-evoked airway responses and reduce levels of NO in exhaled air in vivo. Endogenous NO seems to exert a braking action on BDNF-induced enhancement of airway responses and a reduced ability to release NO may be one mechanism for increased airway response during elevated BDNF levels. Taken together this indicates that BDNF may be of importance for airway hyperresponsiveness in vivo. The interaction between BDNF and airway NO formation, and its relation to airway responses, merit further investigation.
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Affiliation(s)
- Lydia Bennedich Kahn
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Groothuis JT, Poelkens F, Wouters CW, Kooijman M, Hopman MTE. Leg intravenous pressure during head-up tilt. J Appl Physiol (1985) 2008; 105:811-5. [PMID: 18635882 DOI: 10.1152/japplphysiol.90304.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Leg vascular resistance is calculated as the arterial-venous pressure gradient divided by blood flow. During orthostatic challenges it is assumed that the hydrostatic pressure contributes equally to leg arterial, as well as to leg venous pressure. Because of venous valves, one may question whether, during orthostatic challenges, a continuous hydrostatic column is formed and if leg venous pressure is equal to the hydrostatic pressure. The purpose of this study was, therefore, to measure intravenous pressure in the great saphenous vein of 12 healthy individuals during 30 degrees and 70 degrees head-up tilt and compare this with the calculated hydrostatic pressure. The height difference between the heart and the right medial malleolus level represented the hydrostatic column. The results demonstrate that there were no differences between the measured intravenous pressure and the calculated hydrostatic pressure during 30 degrees (47.2 +/- 1.0 and 46.9 +/- 1.5 mmHg, respectively) and 70 degrees head-up tilt (83.9 +/- 0.9 and 85.1 +/- 1.2 mmHg, respectively). Steady-state levels of intravenous pressure were reached after 95 +/- 12 s during 30 degrees and 161 +/- 15 s during 70 degrees head-up tilt. In conclusion, the measured leg venous pressure is similar to the calculated hydrostatic pressure during orthostatic challenges. Therefore, the assumption that hydrostatic pressure contributes equally to leg arterial as well as to leg venous pressure during orthostatic challenges can be made.
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Affiliation(s)
- Jan T Groothuis
- Radboud Univ. Nijmegen Medical Centre, Dept. of Physiology, Geert Grooteplein-noord 21, 6525 EZ Nijmegen, The Netherlands
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Sopi RB, Martin RJ, Haxhiu MA, Dreshaj IA, Yao Q, Jafri A, Zaidi SIA. Role of brain-derived neurotrophic factor in hyperoxia-induced enhancement of contractility and impairment of relaxation in lung parenchyma. Am J Physiol Lung Cell Mol Physiol 2008; 295:L348-55. [PMID: 18515408 DOI: 10.1152/ajplung.00067.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Prolonged hyperoxic exposure contributes to neonatal lung injury, and airway hyperreactivity is characterized by enhanced contraction and impaired relaxation of airway smooth muscle. Our previous data demonstrate that hyperoxia in rat pups upregulates expression of brain-derived neurotrophic factor (BDNF) mRNA and protein, disrupts NO-cGMP signaling, and impairs cAMP production in airway smooth muscle. We hypothesized that BDNF-tyrosine kinase B (TrkB) signaling plays a functional role in airway hyperreactivity via upregulation of cholinergic mechanisms in hyperoxia-exposed lungs. Five-day-old rat pups were exposed to >or=95% oxygen or room air for 7 days and administered daily tyrosine kinase inhibitor K-252a (50 microg x kg(-1) x day(-1) i.p.) to block BDNF-TrkB signaling or vehicle. Lungs were removed for HPLC measurement of ACh or for in vitro force measurement of lung parenchymal strips. ACh content doubled in hyperoxic compared with room air-exposed lungs. K-252a treatment of hyperoxic pups restored ACh content to room air levels. Hyperoxia increased contraction and impaired relaxation of lung strips in response to incremental electrical field stimulation. K-252a administration to hyperoxic pups reversed this increase in contraction and decrease in relaxation. K-252a or TrkB-Fc was used to block the effect of exogenous BDNF in vitro. Both K-252a and TrkB-Fc blocked the effects of exogenous BDNF. Hyperoxia decreased cAMP and cGMP levels in lung strips, and blockade of BDNF-TrkB signaling restored cAMP but not cGMP to control levels. Therefore, hyperoxia-induced increase in activity of BDNF-TrkB receptor signaling appears to play a critical role in enhancing cholinergically mediated contractile responses of lung parenchyma.
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Affiliation(s)
- Ramadan B Sopi
- Deptartment of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, 11100 Euclid Ave., Cleveland, OH 44106-6009, USA
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Calbet JAL, Gonzalez-Alonso J, Helge JW, Søndergaard H, Munch-Andersen T, Boushel R, Saltin B. Cardiac output and leg and arm blood flow during incremental exercise to exhaustion on the cycle ergometer. J Appl Physiol (1985) 2007; 103:969-78. [PMID: 17600155 DOI: 10.1152/japplphysiol.01281.2006] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine central and peripheral hemodynamic responses to upright leg cycling exercise, nine physically active men underwent measurements of arterial blood pressure and gases, as well as femoral and subclavian vein blood flows and gases during incremental exercise to exhaustion (Wmax). Cardiac output (CO) and leg blood flow (BF) increased in parallel with exercise intensity. In contrast, arm BF remained at 0.8 l/min during submaximal exercise, increasing to 1.2 +/- 0.2 l/min at maximal exercise (P < 0.05) when arm O(2) extraction reached 73 +/- 3%. The leg received a greater percentage of the CO with exercise intensity, reaching a value close to 70% at 64% of Wmax, which was maintained until exhaustion. The percentage of CO perfusing the trunk decreased with exercise intensity to 21% at Wmax, i.e., to approximately 5.5 l/min. For a given local Vo(2), leg vascular conductance (VC) was five- to sixfold higher than arm VC, despite marked hemoglobin deoxygenation in the subclavian vein. At peak exercise, arm VC was not significantly different than at rest. Leg Vo(2) represented approximately 84% of the whole body Vo(2) at intensities ranging from 38 to 100% of Wmax. Arm Vo(2) contributed between 7 and 10% to the whole body Vo(2). From 20 to 100% of Wmax, the trunk Vo(2) (including the gluteus muscles) represented between 14 and 15% of the whole body Vo(2). In summary, vasoconstrictor signals efficiently oppose the vasodilatory metabolites in the arms, suggesting that during whole body exercise in the upright position blood flow is differentially regulated in the upper and lower extremities.
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Affiliation(s)
- Jose A L Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Spain.
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