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Cardet JC, Bulkhi AA, Lockey RF. Nonrespiratory Comorbidities in Asthma. J Allergy Clin Immunol Pract 2021; 9:3887-3897. [PMID: 34492402 PMCID: PMC8631133 DOI: 10.1016/j.jaip.2021.08.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/11/2021] [Accepted: 08/15/2021] [Indexed: 12/12/2022]
Abstract
Asthma is a chronic heterogeneous airway disease. Common comorbid conditions are often disproportionately present in severe asthma. Optimal care of patients with asthma requires the recognition and treatment of these comorbid conditions. This review outlines the pathophysiological mechanisms between nonrespiratory comorbid conditions and asthma and their effect on asthma outcomes. They include: type 2 diabetes mellitus, hypertension, atherosclerotic cardiovascular disease, adrenal and thyroid gland diseases, pregnancy, osteoporosis, adverse effects from medications, and mental health disorders. Studies indicate how poor glycemic control of type 2 diabetes mellitus is associated with not only greater health care utilization but poorer asthma outcomes. Also, a large health care claims database indicates that a substantial proportion of pregnant women have uncontrolled asthma and are prescribed suboptimal controller therapy. Additional data about these nonrespiratory comorbidities and medications known to benefit both nonrespiratory comorbidities and asthma are necessary.
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Affiliation(s)
- Juan Carlos Cardet
- Division of Allergy and Immunology, Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Fla
| | - Adeeb A Bulkhi
- Division of Allergy and Immunology, Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Fla; Department of Internal Medicine, College of Medicine, Umm Al Qura University, Makkah, Saudi Arabia
| | - Richard F Lockey
- Division of Allergy and Immunology, Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Fla; Department of Internal Medicine, James A. Haley Veterans' Hospital, Tampa, Fla.
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Aritake H, Tamada T, Murakami K, Gamo S, Nara M, Kazama I, Ichinose M, Sugiura H. Effects of indacaterol on the LPS-evoked changes in fluid secretion rate and pH in swine tracheal membrane. Pflugers Arch 2021; 473:883-896. [PMID: 34031755 PMCID: PMC8164627 DOI: 10.1007/s00424-021-02560-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 11/21/2022]
Abstract
An acquired dysregulation of airway secretion is likely involved in the pathophysiology of chronic bronchitis and chronic obstructive pulmonary disease (COPD). Nowadays, it is widely known that several kinds of long-acting bronchodilators reduce the frequency of COPD exacerbations. However, limited data are available concerning the complementary additive effects on airflow obstruction. Using an optical method and a selective pH indicator, we succeeded in evaluating the gland secretion rate and the pH in swine tracheal membrane. A physiologically relevant concentration of acetylcholine (ACh) 100 nM induced a gradual increase in the amount of gland secretion. Lipopolysaccharides (LPS) accelerated the ACh-induced secretory responses up to around threefold and lowered the pH level significantly. Long-acting β2-agonists (LABAs) including indacaterol (IND), formoterol, and salmeterol restored the LPS-induced changes in both the hypersecretion and acidification. The subsequent addition of the long-acting muscarine antagonist, glycopyrronium, further increased the pH values. Two different inhibitors for cystic fibrosis transmembrane conductance regulator (CFTR), NPPB and CFTRinh172, abolished the IND-mediated pH normalization in the presence of both ACh and ACh + LPS. Both immunofluorescence staining and western blotting analysis revealed that LPS downregulated the abundant expression of CFTR protein. However, IND did not restore the LPS-induced decrease in CFTR expression on Calu-3 cells. These findings suggest that the activation of cAMP-dependent HCO3− secretion through CFTR would be partly involved in the IND-mediated pH normalization in gland secretion and may be suitable for the maintenance of airway defense against exacerbating factors including LPS.
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Affiliation(s)
- Hidemi Aritake
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Tsutomu Tamada
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
| | - Koji Murakami
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Shunichi Gamo
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Masayuki Nara
- National Hospital Organization Akita National Hospital, Yurihonjo, Japan
| | - Itsuro Kazama
- Miyagi University School of Nursing Graduate School of Nursing, Kurokawa-gun, Japan
| | | | - Hisatoshi Sugiura
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
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Gamo S, Tamada T, Murakami K, Muramatsu S, Aritake H, Nara M, Kazama I, Okazaki T, Sugiura H, Ichinose M. TLR7 agonist attenuates acetylcholine-induced, Ca 2+ -dependent ionic currents in swine tracheal submucosal gland cells. Exp Physiol 2018; 103:1543-1559. [PMID: 30194882 DOI: 10.1113/ep087221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/04/2018] [Indexed: 01/17/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does Toll-like receptor 7 (TLR7) have any direct effects on Ca2+ -dependent physiological function of tracheal submucosal gland cells? What is the main finding and its importance? TLR7 is co-localized with SERCA2 in tracheal submucosal gland cells and causes a rapid attenuation of acetylcholine (ACh)-induced, Ca2+ -dependent ionic currents through the activation of SERCA2-dependent Ca2+ clearance. TLR7 is abundantly expressed in the airways of both swine and healthy human subjects, but is significantly downregulated in chronic obstructive pulmonary disease (COPD) airways. These findings suggest that a dysfunction of TLR7 in COPD removes the brake on ACh-induced serous secretion during viral infections, resulting in prolonged airway hypersecretion, and that it is one of the triggers of COPD exacerbations. ABSTRACT Airway surface fluids are mainly secreted from submucosal glands (SMGs) and play important roles in the defence of airways via the activation of mucociliary transport. Toll-like receptor 7 (TLR7) recognizes and eliminates single stranded RNA (ssRNA) viruses through the induction of innate immunity. However, there is no obvious connection between TLR7 and mucus secretion, aside from TLR7 recognizing ssRNA viruses, which are often associated with airway hypersecretion in chronic obstructive pulmonary disease (COPD). Here, we investigated whether TLR7 has any direct effects on the Ca2+ -dependent physiological function of tracheal SMG cells. Patch-clamp analyses revealed that TLR7 ligand inhibited the acetylcholine (ACh)-induced ionic currents in isolated tracheal SMG cells. Intracellular calcium assays and pharmacological analyses revealed that TLR7 attenuated the transient rises in the intracellular calcium concentration evoked by ACh by activating sarco/endoplasmic reticulum Ca2+ -ATPase 2 (SERCA2). Immunofluorescence staining and immunohistochemical staining revealed that TLR7 was co-localized with SERCA2. These findings suggest that the activation of TLR7 during viral infections contributes to the rapid attenuation of ACh-induced ionic currents through an increase in SERCA2-dependent Ca2+ clearance in healthy airway SMG cells. Our study also revealed that TLR7 expression was significantly downregulated in COPD airways. Based on these findings, we speculate that a dysfunction of TLR7 may not only have an adverse effect on the elimination of these viruses but also remove the brake on ACh-induced serous secretion, resulting in prolonged hypersecretion and acting as one of the triggers of COPD exacerbations.
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Affiliation(s)
- Shunichi Gamo
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Tsutomu Tamada
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Koji Murakami
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Soshi Muramatsu
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Hidemi Aritake
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Masayuki Nara
- Clinical Research, Innovation and Education Center, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Itsuro Kazama
- Miyagi University, School of Nursing, 1-1 Gakuen, Taiwa-cho, Kurokawa-gun, Miyagi, 981-3298, Japan
| | - Tatsuma Okazaki
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Hisatoshi Sugiura
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
| | - Masakazu Ichinose
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi 980-8574, Aoba-ku, Sendai, Japan
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Abstract
Submucosal glands contribute to airway surface liquid (ASL), a film that protects all airway surfaces. Glandular mucus comprises electrolytes, water, the gel-forming mucin MUC5B, and hundreds of different proteins with diverse protective functions. Gland volume per unit area of mucosal surface correlates positively with impaction rate of inhaled particles. In human main bronchi, the volume of the glands is ∼ 50 times that of surface goblet cells, but the glands diminish in size and frequency distally. ASL and its trapped particles are removed from the airways by mucociliary transport. Airway glands have a tubuloacinar structure, with a single terminal duct, a nonciliated collecting duct, then branching secretory tubules lined with mucous cells and ending in serous acini. They allow for a massive increase in numbers of mucus-producing cells without replacing surface ciliated cells. Active secretion of Cl(-) and HCO3 (-) by serous cells produces most of the fluid of gland secretions. Glands are densely innervated by tonically active, mutually excitatory airway intrinsic neurons. Most gland mucus is secreted constitutively in vivo, with large, transient increases produced by emergency reflex drive from the vagus. Elevations of [cAMP]i and [Ca(2+)]i coordinate electrolyte and macromolecular secretion and probably occur together for baseline activity in vivo, with cholinergic elevation of [Ca(2+)]i being mainly responsive for transient increases in secretion. Altered submucosal gland function contributes to the pathology of all obstructive diseases, but is an early stage of pathogenesis only in cystic fibrosis.
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Affiliation(s)
- Jonathan H Widdicombe
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
| | - Jeffrey J Wine
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
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Muramatsu S, Tamada T, Nara M, Murakami K, Kikuchi T, Kanehira M, Maruyama Y, Ebina M, Nukiwa T, Ichinose M. Flagellin/TLR5 signaling potentiates airway serous secretion from swine tracheal submucosal glands. Am J Physiol Lung Cell Mol Physiol 2013; 305:L819-30. [PMID: 24097563 DOI: 10.1152/ajplung.00053.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Airway serous secretion is essential for the maintenance of mucociliary transport in airway mucosa, which is responsible for the upregulation of mucosal immunity. Although there are many articles concerning the importance of Toll-like receptors (TLRs) in airway immune systems, the direct relationship between TLRs and airway serous secretion has not been well investigated. Here, we focused on whether TLR5 ligand flagellin, which is one of the components of Pseudomonas aeruginosa, is involved in the upregulation of airway serous secretion. Freshly isolated swine tracheal submucosal gland cells were prepared, and the standard patch-clamp technique was applied for measurements of the whole cell ionic responses of these cells. Flagellin showed potentiating effects on these oscillatory currents induced by physiologically relevant low doses of acetylcholine (ACh) in a dose-dependent manner. These potentiating effects were TLR5 dependent but TLR4 independent. Both nitric oxide (NO) synthase inhibitors and cGMP-dependent protein kinase (cGK) inhibitors abolished these flagellin-induced potentiating effects. Furthermore, TLR5 was abundantly expressed on tracheal submucosal glands. Flagellin/TLR5 signaling further accelerated the intracellular NO synthesis induced by ACh. These findings suggest that TLR5 takes part in the airway mucosal defense systems as a unique endogenous potentiator of airway serous secretions and that NO/cGMP/cGK signaling is involved in this rapid potentiation by TLR5 signaling.
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Affiliation(s)
- Soshi Muramatsu
- Dept. of Respiratory Medicine, Tohoku Univ. Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, JAPAN.
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Murakami K, Tamada T, Nara M, Muramatsu S, Kikuchi T, Kanehira M, Maruyama Y, Ebina M, Nukiwa T. Toll-Like Receptor 4 Potentiates Ca2+-Dependent Secretion of Electrolytes from Swine Tracheal Glands. Am J Respir Cell Mol Biol 2011; 45:1101-10. [DOI: 10.1165/rcmb.2011-0020oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Qu F, Qin XQ, Cui YR, Xiang Y, Tan YR, Liu HJ, Peng LH, Zhou XY, Liu C, Zhu XL. Ozone stress down-regulates the expression of cystic fibrosis transmembrane conductance regulator in human bronchial epithelial cells. Chem Biol Interact 2009; 179:219-26. [DOI: 10.1016/j.cbi.2008.10.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 10/29/2008] [Accepted: 10/31/2008] [Indexed: 10/21/2022]
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Nagaoka M, Nara M, Tamada T, Kume H, Oguma T, Kikuchi T, Zaini J, Moriya T, Ichinose M, Tamura G, Hattori T. Regulation of adenosine 5'-triphosphate (ATP)-gated P2X(4) receptors on tracheal smooth muscle cells. Respir Physiol Neurobiol 2009; 166:61-7. [PMID: 19429520 DOI: 10.1016/j.resp.2009.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 02/01/2009] [Accepted: 02/08/2009] [Indexed: 11/23/2022]
Abstract
We examined the effects of extracellular adenosine 5'-triphosphate (ATP) on single airway smooth muscle (ASM) cells from porcine trachea using a patch-clamp technique. ATP induced a sustained inward current. Phospholipase C inhibitor U-73122 failed to inhibit the current, suggesting the involvement of P2X receptor. A specific effecter of P2X(4), ivermectin, augmented the current indicating the existence of P2X(4) receptors. Immunohistochemistry and reverse transcription/polymerase chain reaction analysis and Western blot analysis also showed the distribution of the P2X(4) receptors. The inward current was reduced by SKF-96365, an inhibitor of both voltage-dependent Ca(2+) channels (VDCCs) and voltage-independent Ca(2+) channels, although a VDCC antagonist, verapamil, did not affect the current. SKF-96365 caused complete suppression of both the increase in the intracellular Ca(2+) concentration and the contraction of ASM cells induced by ATP. Our results demonstrate that P2X(4) receptors exist on ASM and that the receptors are responsible for Ca(2+) influx. These findings suggest that the Ca(2+) influx regulated by P2X(4) receptors plays an important role in ASM contraction by a pathway distinct from VDCC.
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Tamada T, Nara M, Kanatsuka H, Nagaoka M, Koshida R, Tamura G, Hattori T. A potentiating effect of endogenous NO in the physiologic secretion from airway submucosal glands. Am J Respir Cell Mol Biol 2007; 37:357-65. [PMID: 17463393 DOI: 10.1165/rcmb.2006-0389oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
It is known that several second messengers, such as Ca(2+) or cAMP, play important roles in the intracellular pathway of electrolyte secretion in tracheal submucosal gland. However, the participation of cGMP, and therefore nitric oxide (NO), is not well understood. To investigate the physiologic role of NO, we first examined whether tracheal glands can synthesize NO in response to acetylcholine (ACh), and then whether endogenous NO has some effects on the ACh-triggered ionic currents. From the experiments using the NO-specific fluorescent indicator 4,5-diaminofluorescein diacetate salt (DAF-2DA), we found that a physiologically relevant low dose of ACh (100 nM) stimulated the endogenous NO synthesis, and it was almost completely suppressed in the presence of the nonspecific NO synthase (NOS) inhibitor Nomega-Nitro-L-arginine Methyl Ester Hydrochloride (L-NAME) or the neuronal NOS (nNOS)-specific inhibitor 7-Nitroindazole (7-NI). Patch-clamp experiments revealed that both the NOS inhibitors (L-NAME or 7-NI) and cGK inhibitors (KT-5823 or Rp-8-Br-cGMP) partially decreased ionic currents induced by 30 nM of ACh, but not in the case of 300 nM of ACh. Our results indicate that NO can be synthesized through the activation of nNOS endogenously and has potentiating effects on the gland secretion, under a physiologically relevant ACh stimulation. When cells were stimulated by an inadequately potent dose of ACh, which caused an excess elevation in [Ca(2+)](i), the cells were desensitized. Therefore, due to NO, gland cells become more sensitive to calcium signaling and are able to maintain electrolyte secretion without desensitization.
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Affiliation(s)
- Tsutomu Tamada
- Department of Infectious and Respiratory Diseases, Tohoku University School of Medicine, 1-1, Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan.
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Liu H, Mamoon AM, Farley JM. Prostanoids Secreted by Alveolar Macrophages Enhance Ionic Currents in Swine Tracheal Submucosal Gland Cells. J Pharmacol Exp Ther 2005; 315:729-39. [PMID: 16055675 DOI: 10.1124/jpet.105.088542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the effect of substances released by swine alveolar macrophages (AMs) on ionic currents in airway submucosal gland cells (SGCs). AMs obtained by lavage were activated by 24-h zymosan exposure (0.1 mg/ml). Supernatant was collected and used to stimulate short-circuit current changes (DeltaI(SC)) in SGC monolayers in Ussing chambers. Dexamethasone (1 microM) or indomethacin (5 muM) during zymosan exposure of AMs reduced or abolished the supernatant-induced DeltaI(SC). Zymosan exposure induced a 5-fold increase in cyclooxygenase (COX)-2 but not COX-1 protein levels in AMs. Prostaglandin E(2) (PGE(2)) concentration in the supernatant from zymosan-activated AMs was 550 +/- 10 nM (n = 3) compared with 28 +/- 3 nM for unstimulated AMs (n = 3). PGE(2), applied serosally, induced DeltaI(SC) with an EC(50) of 15.5 +/- 1.3 nM (n = 4) and 3.6 +/- 1.8 microM (n = 3) when applied apically. Four types of endoprostanoid receptors (EP(1-4)) were detected in SGCs using Western blot. PGE(2)-induced DeltaI(SC) were inhibited by AH6809 (6-isopropoxy-9-oxoxanthene-2-carboxylic acid) but not by SC19220 (8-chloro-dibenzo[b,f][1,4]oxazepine-10(11H)-carboxylic acid, 2-acetylhydrazide), suggesting that endoprostanoid (EP)(2) but not EP(1) receptors were activated by PGE(2). Pretreatment of SGCs with supernatant from zymosan-activated AMs, PGE(2), or forskolin enhanced the sensitivity to acetylcholine (ACh)-induced DeltaI(SC). PGE(2)-induced DeltaI(SC) were blocked by charybdotoxin (ChTX), chromanol 293B, or glibenclamide. ACh-induced DeltaI(SC) were only blocked by ChTX or glibenclamide. None of these blockers altered PGE(2) pretreatment-induced sensitization of ACh-induced DeltaI(SC). These results demonstrate that prostanoids released from activated AMs directly increase cystic fibrosis transmembrane conductance regulator and K(+) channel activity. ACh-induced DeltaI(SC) are also enhanced due to enhanced activation of Ca(2+)-activated K(+) channels (K(Ca)).
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Affiliation(s)
- Huiling Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, 39216, USA
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Sasamori K, Sasaki T, Takasawa S, Tamada T, Nara M, Irokawa T, Shimura S, Shirato K, Hattori T. Cyclic ADP-ribose, a putative Ca2+-mobilizing second messenger, operates in submucosal gland acinar cells. Am J Physiol Lung Cell Mol Physiol 2004; 287:L69-78. [PMID: 14990397 DOI: 10.1152/ajplung.00454.2003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cyclic ADP-ribose (cADPR), a putative Ca(2+)-mobilizing second messenger, has been reported to operate in several mammalian cells. To investigate whether cADPR is involved in electrolyte secretion from airway glands, we used a patch-clamp technique, the measurement of microsomal Ca(2+) release, quantification of cellular cADPR, and RT-PCR for CD38 mRNA in human and feline tracheal glands. cADPR (>6 microM), infused into the cell via the patch pipette, caused ionic currents dependent on cellular Ca(2+). Infusions of lower concentrations (2-4 microM) of cADPR or inositol 1,4,5-trisphosphate (IP(3)) alone were without effect on the baseline current, but a combined application of cADPR and IP(3) mimicked the cellular response to low concentrations of acetylcholine (ACh). Microsomes derived from the isolated glands released Ca(2+) in response to both IP(3) and cADPR. cADPR released Ca(2+) from microsomes desensitized to IP(3) or those treated with heparin. The mRNA for CD38, an enzyme protein involved in cADPR metabolism, was detected in human tissues, including tracheal glands, and the cellular content of cADPR was increased with physiologically relevant concentrations of ACh. We conclude that cADPR, in concert with IP(3), operates in airway gland acinar cells to mobilize Ca(2+), resulting in Cl(-) secretion.
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Affiliation(s)
- Kan Sasamori
- Division of Respiratory and Infectious Diseases, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Iwase N, Sasaki T, Oshiro T, Tamada T, Nara M, Sasamori K, Hattori T, Shirato K, Maruyama Y. Differential effect of epidermal growth factor on serous and mucous cells in porcine airway submucosal gland. Respir Physiol Neurobiol 2002; 132:307-19. [PMID: 12208089 DOI: 10.1016/s1569-9048(02)00118-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Using a patch-clamp technique, we found that the fresh porcine submucosal gland acinar cells contained two functionally distinct cell populations, i.e. physiologically relevant concentration of acetylcholine (ACh, 30 nM) induced two distinct patterns of electric response in tracheal gland acinar cells. One was characterized by an outstanding oscillatory Cl(-)-current activity, and the other was with poor Cl(-)-current response but with a comparable K(+)-current. We examined the effect of epidermal growth factor (EGF) on the ACh-induced electric responses in these cells. EGF affected only the latter (K(+)-prominent) cell type to potentiate significantly the ACh-induced K(+)-current. An immunohistochemistry revealed that the receptor for EGF was identified preferentially on the mucous, but not serous, cells. Genistein, one of the tyrosine-kinase inhibitors, abolished the augmentation effect of EGF on the ACh-induced current. Thus, we identified the serous cell with a Cl(-)-rich current in response to ACh and the mucous cell with a K(+)-dominant response. Moreover, EGF affected the mucous cells alone to potentiate the ACh-induced electric response. EGF may contribute to the pathophysiological alterations in chronic inflammatory airways both in morphological (mucous cell hypertrophy/hyperplasia) and functional (thick viscous hypersecretion) ways.
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Affiliation(s)
- Nobuhisa Iwase
- The First Department of Internal Medicine, Tohoku University Graduate School of Medicine, 1-1, Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
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